arch/ia64/kernel/perfmon.c

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This source file includes following definitions.
pfm_put_task
pfm_protect_ctx_ctxsw
pfm_unprotect_ctx_ctxsw
pfmfs_init_fs_context
pfm_clear_psr_pp
pfm_set_psr_pp
pfm_clear_psr_up
pfm_set_psr_up
pfm_get_psr
pfm_set_psr_l
pfm_freeze_pmu
pfm_unfreeze_pmu
pfm_restore_ibrs
pfm_restore_dbrs
pfm_read_soft_counter
pfm_write_soft_counter
pfm_get_new_msg
pfm_get_next_msg
pfm_reset_msgq
pfm_context_alloc
pfm_context_free
pfm_mask_monitoring
pfm_restore_monitoring
pfm_save_pmds
pfm_restore_pmds
pfm_copy_pmds
pfm_copy_pmcs
pfm_restore_pmcs
pfm_uuid_cmp
pfm_buf_fmt_exit
pfm_buf_fmt_getsize
pfm_buf_fmt_validate
pfm_buf_fmt_init
pfm_buf_fmt_restart
pfm_buf_fmt_restart_active
__pfm_find_buffer_fmt
pfm_find_buffer_fmt
pfm_register_buffer_fmt
pfm_unregister_buffer_fmt
pfm_reserve_session
pfm_unreserve_session
pfm_remove_smpl_mapping
pfm_free_smpl_buffer
pfm_exit_smpl_buffer
init_pfm_fs
pfm_read
pfm_write
pfm_poll
pfm_ioctl
pfm_do_fasync
pfm_fasync
pfm_syswide_force_stop
pfm_syswide_cleanup_other_cpu
pfm_flush
pfm_close
pfmfs_dname
pfm_alloc_file
pfm_remap_buffer
pfm_smpl_buffer_alloc
pfm_bad_permissions
pfarg_is_sane
pfm_setup_buffer_fmt
pfm_reset_pmu_state
pfm_ctx_getsize
pfm_task_incompatible
pfm_get_task
pfm_context_create
pfm_new_counter_value
pfm_reset_regs_masked
pfm_reset_regs
pfm_write_pmcs
pfm_write_pmds
pfm_read_pmds
pfm_mod_write_pmcs
pfm_mod_read_pmds
pfm_use_debug_registers
pfm_release_debug_registers
pfm_restart
pfm_debug
pfm_write_ibr_dbr
pfm_write_ibrs
pfm_write_dbrs
pfm_mod_write_ibrs
pfm_mod_write_dbrs
pfm_get_features
pfm_stop
pfm_start
pfm_get_pmc_reset
pfm_check_task_exist
pfm_context_load
pfm_context_unload
pfm_exit_thread
pfm_check_task_state
sys_perfmonctl
pfm_resume_after_ovfl
pfm_context_force_terminate
pfm_handle_work
pfm_notify_user
pfm_ovfl_notify_user
pfm_end_notify_user
pfm_overflow_handler
pfm_do_interrupt_handler
pfm_interrupt_handler
pfm_proc_start
pfm_proc_next
pfm_proc_stop
pfm_proc_show_header
pfm_proc_show
pfm_syst_wide_update_task
pfm_force_cleanup
pfm_save_regs
pfm_save_regs
pfm_lazy_save_regs
pfm_load_regs
pfm_load_regs
pfm_flush_pmds
pfm_alt_save_pmu_state
pfm_alt_restore_pmu_state
pfm_install_alt_pmu_interrupt
pfm_remove_alt_pmu_interrupt
pfm_probe_pmu
pfm_init
pfm_init_percpu
dump_pmu_state
pfm_inherit
sys_perfmonctl
   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * This file implements the perfmon-2 subsystem which is used
   4  * to program the IA-64 Performance Monitoring Unit (PMU).
   5  *
   6  * The initial version of perfmon.c was written by
   7  * Ganesh Venkitachalam, IBM Corp.
   8  *
   9  * Then it was modified for perfmon-1.x by Stephane Eranian and
  10  * David Mosberger, Hewlett Packard Co.
  11  *
  12  * Version Perfmon-2.x is a rewrite of perfmon-1.x
  13  * by Stephane Eranian, Hewlett Packard Co.
  14  *
  15  * Copyright (C) 1999-2005  Hewlett Packard Co
  16  *               Stephane Eranian <eranian@hpl.hp.com>
  17  *               David Mosberger-Tang <davidm@hpl.hp.com>
  18  *
  19  * More information about perfmon available at:
  20  *      http://www.hpl.hp.com/research/linux/perfmon
  21  */
  22 
  23 #include <linux/module.h>
  24 #include <linux/kernel.h>
  25 #include <linux/sched.h>
  26 #include <linux/sched/task.h>
  27 #include <linux/sched/task_stack.h>
  28 #include <linux/interrupt.h>
  29 #include <linux/proc_fs.h>
  30 #include <linux/seq_file.h>
  31 #include <linux/init.h>
  32 #include <linux/vmalloc.h>
  33 #include <linux/mm.h>
  34 #include <linux/sysctl.h>
  35 #include <linux/list.h>
  36 #include <linux/file.h>
  37 #include <linux/poll.h>
  38 #include <linux/vfs.h>
  39 #include <linux/smp.h>
  40 #include <linux/pagemap.h>
  41 #include <linux/mount.h>
  42 #include <linux/pseudo_fs.h>
  43 #include <linux/bitops.h>
  44 #include <linux/capability.h>
  45 #include <linux/rcupdate.h>
  46 #include <linux/completion.h>
  47 #include <linux/tracehook.h>
  48 #include <linux/slab.h>
  49 #include <linux/cpu.h>
  50 
  51 #include <asm/errno.h>
  52 #include <asm/intrinsics.h>
  53 #include <asm/page.h>
  54 #include <asm/perfmon.h>
  55 #include <asm/processor.h>
  56 #include <asm/signal.h>
  57 #include <linux/uaccess.h>
  58 #include <asm/delay.h>
  59 
  60 #ifdef CONFIG_PERFMON
  61 /*
  62  * perfmon context state
  63  */
  64 #define PFM_CTX_UNLOADED        1       /* context is not loaded onto any task */
  65 #define PFM_CTX_LOADED          2       /* context is loaded onto a task */
  66 #define PFM_CTX_MASKED          3       /* context is loaded but monitoring is masked due to overflow */
  67 #define PFM_CTX_ZOMBIE          4       /* owner of the context is closing it */
  68 
  69 #define PFM_INVALID_ACTIVATION  (~0UL)
  70 
  71 #define PFM_NUM_PMC_REGS        64      /* PMC save area for ctxsw */
  72 #define PFM_NUM_PMD_REGS        64      /* PMD save area for ctxsw */
  73 
  74 /*
  75  * depth of message queue
  76  */
  77 #define PFM_MAX_MSGS            32
  78 #define PFM_CTXQ_EMPTY(g)       ((g)->ctx_msgq_head == (g)->ctx_msgq_tail)
  79 
  80 /*
  81  * type of a PMU register (bitmask).
  82  * bitmask structure:
  83  *      bit0   : register implemented
  84  *      bit1   : end marker
  85  *      bit2-3 : reserved
  86  *      bit4   : pmc has pmc.pm
  87  *      bit5   : pmc controls a counter (has pmc.oi), pmd is used as counter
  88  *      bit6-7 : register type
  89  *      bit8-31: reserved
  90  */
  91 #define PFM_REG_NOTIMPL         0x0 /* not implemented at all */
  92 #define PFM_REG_IMPL            0x1 /* register implemented */
  93 #define PFM_REG_END             0x2 /* end marker */
  94 #define PFM_REG_MONITOR         (0x1<<4|PFM_REG_IMPL) /* a PMC with a pmc.pm field only */
  95 #define PFM_REG_COUNTING        (0x2<<4|PFM_REG_MONITOR) /* a monitor + pmc.oi+ PMD used as a counter */
  96 #define PFM_REG_CONTROL         (0x4<<4|PFM_REG_IMPL) /* PMU control register */
  97 #define PFM_REG_CONFIG          (0x8<<4|PFM_REG_IMPL) /* configuration register */
  98 #define PFM_REG_BUFFER          (0xc<<4|PFM_REG_IMPL) /* PMD used as buffer */
  99 
 100 #define PMC_IS_LAST(i)  (pmu_conf->pmc_desc[i].type & PFM_REG_END)
 101 #define PMD_IS_LAST(i)  (pmu_conf->pmd_desc[i].type & PFM_REG_END)
 102 
 103 #define PMC_OVFL_NOTIFY(ctx, i) ((ctx)->ctx_pmds[i].flags &  PFM_REGFL_OVFL_NOTIFY)
 104 
 105 /* i assumed unsigned */
 106 #define PMC_IS_IMPL(i)    (i< PMU_MAX_PMCS && (pmu_conf->pmc_desc[i].type & PFM_REG_IMPL))
 107 #define PMD_IS_IMPL(i)    (i< PMU_MAX_PMDS && (pmu_conf->pmd_desc[i].type & PFM_REG_IMPL))
 108 
 109 /* XXX: these assume that register i is implemented */
 110 #define PMD_IS_COUNTING(i) ((pmu_conf->pmd_desc[i].type & PFM_REG_COUNTING) == PFM_REG_COUNTING)
 111 #define PMC_IS_COUNTING(i) ((pmu_conf->pmc_desc[i].type & PFM_REG_COUNTING) == PFM_REG_COUNTING)
 112 #define PMC_IS_MONITOR(i)  ((pmu_conf->pmc_desc[i].type & PFM_REG_MONITOR)  == PFM_REG_MONITOR)
 113 #define PMC_IS_CONTROL(i)  ((pmu_conf->pmc_desc[i].type & PFM_REG_CONTROL)  == PFM_REG_CONTROL)
 114 
 115 #define PMC_DFL_VAL(i)     pmu_conf->pmc_desc[i].default_value
 116 #define PMC_RSVD_MASK(i)   pmu_conf->pmc_desc[i].reserved_mask
 117 #define PMD_PMD_DEP(i)     pmu_conf->pmd_desc[i].dep_pmd[0]
 118 #define PMC_PMD_DEP(i)     pmu_conf->pmc_desc[i].dep_pmd[0]
 119 
 120 #define PFM_NUM_IBRS      IA64_NUM_DBG_REGS
 121 #define PFM_NUM_DBRS      IA64_NUM_DBG_REGS
 122 
 123 #define CTX_OVFL_NOBLOCK(c)     ((c)->ctx_fl_block == 0)
 124 #define CTX_HAS_SMPL(c)         ((c)->ctx_fl_is_sampling)
 125 #define PFM_CTX_TASK(h)         (h)->ctx_task
 126 
 127 #define PMU_PMC_OI              5 /* position of pmc.oi bit */
 128 
 129 /* XXX: does not support more than 64 PMDs */
 130 #define CTX_USED_PMD(ctx, mask) (ctx)->ctx_used_pmds[0] |= (mask)
 131 #define CTX_IS_USED_PMD(ctx, c) (((ctx)->ctx_used_pmds[0] & (1UL << (c))) != 0UL)
 132 
 133 #define CTX_USED_MONITOR(ctx, mask) (ctx)->ctx_used_monitors[0] |= (mask)
 134 
 135 #define CTX_USED_IBR(ctx,n)     (ctx)->ctx_used_ibrs[(n)>>6] |= 1UL<< ((n) % 64)
 136 #define CTX_USED_DBR(ctx,n)     (ctx)->ctx_used_dbrs[(n)>>6] |= 1UL<< ((n) % 64)
 137 #define CTX_USES_DBREGS(ctx)    (((pfm_context_t *)(ctx))->ctx_fl_using_dbreg==1)
 138 #define PFM_CODE_RR     0       /* requesting code range restriction */
 139 #define PFM_DATA_RR     1       /* requestion data range restriction */
 140 
 141 #define PFM_CPUINFO_CLEAR(v)    pfm_get_cpu_var(pfm_syst_info) &= ~(v)
 142 #define PFM_CPUINFO_SET(v)      pfm_get_cpu_var(pfm_syst_info) |= (v)
 143 #define PFM_CPUINFO_GET()       pfm_get_cpu_var(pfm_syst_info)
 144 
 145 #define RDEP(x) (1UL<<(x))
 146 
 147 /*
 148  * context protection macros
 149  * in SMP:
 150  *      - we need to protect against CPU concurrency (spin_lock)
 151  *      - we need to protect against PMU overflow interrupts (local_irq_disable)
 152  * in UP:
 153  *      - we need to protect against PMU overflow interrupts (local_irq_disable)
 154  *
 155  * spin_lock_irqsave()/spin_unlock_irqrestore():
 156  *      in SMP: local_irq_disable + spin_lock
 157  *      in UP : local_irq_disable
 158  *
 159  * spin_lock()/spin_lock():
 160  *      in UP : removed automatically
 161  *      in SMP: protect against context accesses from other CPU. interrupts
 162  *              are not masked. This is useful for the PMU interrupt handler
 163  *              because we know we will not get PMU concurrency in that code.
 164  */
 165 #define PROTECT_CTX(c, f) \
 166         do {  \
 167                 DPRINT(("spinlock_irq_save ctx %p by [%d]\n", c, task_pid_nr(current))); \
 168                 spin_lock_irqsave(&(c)->ctx_lock, f); \
 169                 DPRINT(("spinlocked ctx %p  by [%d]\n", c, task_pid_nr(current))); \
 170         } while(0)
 171 
 172 #define UNPROTECT_CTX(c, f) \
 173         do { \
 174                 DPRINT(("spinlock_irq_restore ctx %p by [%d]\n", c, task_pid_nr(current))); \
 175                 spin_unlock_irqrestore(&(c)->ctx_lock, f); \
 176         } while(0)
 177 
 178 #define PROTECT_CTX_NOPRINT(c, f) \
 179         do {  \
 180                 spin_lock_irqsave(&(c)->ctx_lock, f); \
 181         } while(0)
 182 
 183 
 184 #define UNPROTECT_CTX_NOPRINT(c, f) \
 185         do { \
 186                 spin_unlock_irqrestore(&(c)->ctx_lock, f); \
 187         } while(0)
 188 
 189 
 190 #define PROTECT_CTX_NOIRQ(c) \
 191         do {  \
 192                 spin_lock(&(c)->ctx_lock); \
 193         } while(0)
 194 
 195 #define UNPROTECT_CTX_NOIRQ(c) \
 196         do { \
 197                 spin_unlock(&(c)->ctx_lock); \
 198         } while(0)
 199 
 200 
 201 #ifdef CONFIG_SMP
 202 
 203 #define GET_ACTIVATION()        pfm_get_cpu_var(pmu_activation_number)
 204 #define INC_ACTIVATION()        pfm_get_cpu_var(pmu_activation_number)++
 205 #define SET_ACTIVATION(c)       (c)->ctx_last_activation = GET_ACTIVATION()
 206 
 207 #else /* !CONFIG_SMP */
 208 #define SET_ACTIVATION(t)       do {} while(0)
 209 #define GET_ACTIVATION(t)       do {} while(0)
 210 #define INC_ACTIVATION(t)       do {} while(0)
 211 #endif /* CONFIG_SMP */
 212 
 213 #define SET_PMU_OWNER(t, c)     do { pfm_get_cpu_var(pmu_owner) = (t); pfm_get_cpu_var(pmu_ctx) = (c); } while(0)
 214 #define GET_PMU_OWNER()         pfm_get_cpu_var(pmu_owner)
 215 #define GET_PMU_CTX()           pfm_get_cpu_var(pmu_ctx)
 216 
 217 #define LOCK_PFS(g)             spin_lock_irqsave(&pfm_sessions.pfs_lock, g)
 218 #define UNLOCK_PFS(g)           spin_unlock_irqrestore(&pfm_sessions.pfs_lock, g)
 219 
 220 #define PFM_REG_RETFLAG_SET(flags, val) do { flags &= ~PFM_REG_RETFL_MASK; flags |= (val); } while(0)
 221 
 222 /*
 223  * cmp0 must be the value of pmc0
 224  */
 225 #define PMC0_HAS_OVFL(cmp0)  (cmp0 & ~0x1UL)
 226 
 227 #define PFMFS_MAGIC 0xa0b4d889
 228 
 229 /*
 230  * debugging
 231  */
 232 #define PFM_DEBUGGING 1
 233 #ifdef PFM_DEBUGGING
 234 #define DPRINT(a) \
 235         do { \
 236                 if (unlikely(pfm_sysctl.debug >0)) { printk("%s.%d: CPU%d [%d] ", __func__, __LINE__, smp_processor_id(), task_pid_nr(current)); printk a; } \
 237         } while (0)
 238 
 239 #define DPRINT_ovfl(a) \
 240         do { \
 241                 if (unlikely(pfm_sysctl.debug > 0 && pfm_sysctl.debug_ovfl >0)) { printk("%s.%d: CPU%d [%d] ", __func__, __LINE__, smp_processor_id(), task_pid_nr(current)); printk a; } \
 242         } while (0)
 243 #endif
 244 
 245 /*
 246  * 64-bit software counter structure
 247  *
 248  * the next_reset_type is applied to the next call to pfm_reset_regs()
 249  */
 250 typedef struct {
 251         unsigned long   val;            /* virtual 64bit counter value */
 252         unsigned long   lval;           /* last reset value */
 253         unsigned long   long_reset;     /* reset value on sampling overflow */
 254         unsigned long   short_reset;    /* reset value on overflow */
 255         unsigned long   reset_pmds[4];  /* which other pmds to reset when this counter overflows */
 256         unsigned long   smpl_pmds[4];   /* which pmds are accessed when counter overflow */
 257         unsigned long   seed;           /* seed for random-number generator */
 258         unsigned long   mask;           /* mask for random-number generator */
 259         unsigned int    flags;          /* notify/do not notify */
 260         unsigned long   eventid;        /* overflow event identifier */
 261 } pfm_counter_t;
 262 
 263 /*
 264  * context flags
 265  */
 266 typedef struct {
 267         unsigned int block:1;           /* when 1, task will blocked on user notifications */
 268         unsigned int system:1;          /* do system wide monitoring */
 269         unsigned int using_dbreg:1;     /* using range restrictions (debug registers) */
 270         unsigned int is_sampling:1;     /* true if using a custom format */
 271         unsigned int excl_idle:1;       /* exclude idle task in system wide session */
 272         unsigned int going_zombie:1;    /* context is zombie (MASKED+blocking) */
 273         unsigned int trap_reason:2;     /* reason for going into pfm_handle_work() */
 274         unsigned int no_msg:1;          /* no message sent on overflow */
 275         unsigned int can_restart:1;     /* allowed to issue a PFM_RESTART */
 276         unsigned int reserved:22;
 277 } pfm_context_flags_t;
 278 
 279 #define PFM_TRAP_REASON_NONE            0x0     /* default value */
 280 #define PFM_TRAP_REASON_BLOCK           0x1     /* we need to block on overflow */
 281 #define PFM_TRAP_REASON_RESET           0x2     /* we need to reset PMDs */
 282 
 283 
 284 /*
 285  * perfmon context: encapsulates all the state of a monitoring session
 286  */
 287 
 288 typedef struct pfm_context {
 289         spinlock_t              ctx_lock;               /* context protection */
 290 
 291         pfm_context_flags_t     ctx_flags;              /* bitmask of flags  (block reason incl.) */
 292         unsigned int            ctx_state;              /* state: active/inactive (no bitfield) */
 293 
 294         struct task_struct      *ctx_task;              /* task to which context is attached */
 295 
 296         unsigned long           ctx_ovfl_regs[4];       /* which registers overflowed (notification) */
 297 
 298         struct completion       ctx_restart_done;       /* use for blocking notification mode */
 299 
 300         unsigned long           ctx_used_pmds[4];       /* bitmask of PMD used            */
 301         unsigned long           ctx_all_pmds[4];        /* bitmask of all accessible PMDs */
 302         unsigned long           ctx_reload_pmds[4];     /* bitmask of force reload PMD on ctxsw in */
 303 
 304         unsigned long           ctx_all_pmcs[4];        /* bitmask of all accessible PMCs */
 305         unsigned long           ctx_reload_pmcs[4];     /* bitmask of force reload PMC on ctxsw in */
 306         unsigned long           ctx_used_monitors[4];   /* bitmask of monitor PMC being used */
 307 
 308         unsigned long           ctx_pmcs[PFM_NUM_PMC_REGS];     /*  saved copies of PMC values */
 309 
 310         unsigned int            ctx_used_ibrs[1];               /* bitmask of used IBR (speedup ctxsw in) */
 311         unsigned int            ctx_used_dbrs[1];               /* bitmask of used DBR (speedup ctxsw in) */
 312         unsigned long           ctx_dbrs[IA64_NUM_DBG_REGS];    /* DBR values (cache) when not loaded */
 313         unsigned long           ctx_ibrs[IA64_NUM_DBG_REGS];    /* IBR values (cache) when not loaded */
 314 
 315         pfm_counter_t           ctx_pmds[PFM_NUM_PMD_REGS]; /* software state for PMDS */
 316 
 317         unsigned long           th_pmcs[PFM_NUM_PMC_REGS];      /* PMC thread save state */
 318         unsigned long           th_pmds[PFM_NUM_PMD_REGS];      /* PMD thread save state */
 319 
 320         unsigned long           ctx_saved_psr_up;       /* only contains psr.up value */
 321 
 322         unsigned long           ctx_last_activation;    /* context last activation number for last_cpu */
 323         unsigned int            ctx_last_cpu;           /* CPU id of current or last CPU used (SMP only) */
 324         unsigned int            ctx_cpu;                /* cpu to which perfmon is applied (system wide) */
 325 
 326         int                     ctx_fd;                 /* file descriptor used my this context */
 327         pfm_ovfl_arg_t          ctx_ovfl_arg;           /* argument to custom buffer format handler */
 328 
 329         pfm_buffer_fmt_t        *ctx_buf_fmt;           /* buffer format callbacks */
 330         void                    *ctx_smpl_hdr;          /* points to sampling buffer header kernel vaddr */
 331         unsigned long           ctx_smpl_size;          /* size of sampling buffer */
 332         void                    *ctx_smpl_vaddr;        /* user level virtual address of smpl buffer */
 333 
 334         wait_queue_head_t       ctx_msgq_wait;
 335         pfm_msg_t               ctx_msgq[PFM_MAX_MSGS];
 336         int                     ctx_msgq_head;
 337         int                     ctx_msgq_tail;
 338         struct fasync_struct    *ctx_async_queue;
 339 
 340         wait_queue_head_t       ctx_zombieq;            /* termination cleanup wait queue */
 341 } pfm_context_t;
 342 
 343 /*
 344  * magic number used to verify that structure is really
 345  * a perfmon context
 346  */
 347 #define PFM_IS_FILE(f)          ((f)->f_op == &pfm_file_ops)
 348 
 349 #define PFM_GET_CTX(t)          ((pfm_context_t *)(t)->thread.pfm_context)
 350 
 351 #ifdef CONFIG_SMP
 352 #define SET_LAST_CPU(ctx, v)    (ctx)->ctx_last_cpu = (v)
 353 #define GET_LAST_CPU(ctx)       (ctx)->ctx_last_cpu
 354 #else
 355 #define SET_LAST_CPU(ctx, v)    do {} while(0)
 356 #define GET_LAST_CPU(ctx)       do {} while(0)
 357 #endif
 358 
 359 
 360 #define ctx_fl_block            ctx_flags.block
 361 #define ctx_fl_system           ctx_flags.system
 362 #define ctx_fl_using_dbreg      ctx_flags.using_dbreg
 363 #define ctx_fl_is_sampling      ctx_flags.is_sampling
 364 #define ctx_fl_excl_idle        ctx_flags.excl_idle
 365 #define ctx_fl_going_zombie     ctx_flags.going_zombie
 366 #define ctx_fl_trap_reason      ctx_flags.trap_reason
 367 #define ctx_fl_no_msg           ctx_flags.no_msg
 368 #define ctx_fl_can_restart      ctx_flags.can_restart
 369 
 370 #define PFM_SET_WORK_PENDING(t, v)      do { (t)->thread.pfm_needs_checking = v; } while(0);
 371 #define PFM_GET_WORK_PENDING(t)         (t)->thread.pfm_needs_checking
 372 
 373 /*
 374  * global information about all sessions
 375  * mostly used to synchronize between system wide and per-process
 376  */
 377 typedef struct {
 378         spinlock_t              pfs_lock;                  /* lock the structure */
 379 
 380         unsigned int            pfs_task_sessions;         /* number of per task sessions */
 381         unsigned int            pfs_sys_sessions;          /* number of per system wide sessions */
 382         unsigned int            pfs_sys_use_dbregs;        /* incremented when a system wide session uses debug regs */
 383         unsigned int            pfs_ptrace_use_dbregs;     /* incremented when a process uses debug regs */
 384         struct task_struct      *pfs_sys_session[NR_CPUS]; /* point to task owning a system-wide session */
 385 } pfm_session_t;
 386 
 387 /*
 388  * information about a PMC or PMD.
 389  * dep_pmd[]: a bitmask of dependent PMD registers
 390  * dep_pmc[]: a bitmask of dependent PMC registers
 391  */
 392 typedef int (*pfm_reg_check_t)(struct task_struct *task, pfm_context_t *ctx, unsigned int cnum, unsigned long *val, struct pt_regs *regs);
 393 typedef struct {
 394         unsigned int            type;
 395         int                     pm_pos;
 396         unsigned long           default_value;  /* power-on default value */
 397         unsigned long           reserved_mask;  /* bitmask of reserved bits */
 398         pfm_reg_check_t         read_check;
 399         pfm_reg_check_t         write_check;
 400         unsigned long           dep_pmd[4];
 401         unsigned long           dep_pmc[4];
 402 } pfm_reg_desc_t;
 403 
 404 /* assume cnum is a valid monitor */
 405 #define PMC_PM(cnum, val)       (((val) >> (pmu_conf->pmc_desc[cnum].pm_pos)) & 0x1)
 406 
 407 /*
 408  * This structure is initialized at boot time and contains
 409  * a description of the PMU main characteristics.
 410  *
 411  * If the probe function is defined, detection is based
 412  * on its return value: 
 413  *      - 0 means recognized PMU
 414  *      - anything else means not supported
 415  * When the probe function is not defined, then the pmu_family field
 416  * is used and it must match the host CPU family such that:
 417  *      - cpu->family & config->pmu_family != 0
 418  */
 419 typedef struct {
 420         unsigned long  ovfl_val;        /* overflow value for counters */
 421 
 422         pfm_reg_desc_t *pmc_desc;       /* detailed PMC register dependencies descriptions */
 423         pfm_reg_desc_t *pmd_desc;       /* detailed PMD register dependencies descriptions */
 424 
 425         unsigned int   num_pmcs;        /* number of PMCS: computed at init time */
 426         unsigned int   num_pmds;        /* number of PMDS: computed at init time */
 427         unsigned long  impl_pmcs[4];    /* bitmask of implemented PMCS */
 428         unsigned long  impl_pmds[4];    /* bitmask of implemented PMDS */
 429 
 430         char          *pmu_name;        /* PMU family name */
 431         unsigned int  pmu_family;       /* cpuid family pattern used to identify pmu */
 432         unsigned int  flags;            /* pmu specific flags */
 433         unsigned int  num_ibrs;         /* number of IBRS: computed at init time */
 434         unsigned int  num_dbrs;         /* number of DBRS: computed at init time */
 435         unsigned int  num_counters;     /* PMC/PMD counting pairs : computed at init time */
 436         int           (*probe)(void);   /* customized probe routine */
 437         unsigned int  use_rr_dbregs:1;  /* set if debug registers used for range restriction */
 438 } pmu_config_t;
 439 /*
 440  * PMU specific flags
 441  */
 442 #define PFM_PMU_IRQ_RESEND      1       /* PMU needs explicit IRQ resend */
 443 
 444 /*
 445  * debug register related type definitions
 446  */
 447 typedef struct {
 448         unsigned long ibr_mask:56;
 449         unsigned long ibr_plm:4;
 450         unsigned long ibr_ig:3;
 451         unsigned long ibr_x:1;
 452 } ibr_mask_reg_t;
 453 
 454 typedef struct {
 455         unsigned long dbr_mask:56;
 456         unsigned long dbr_plm:4;
 457         unsigned long dbr_ig:2;
 458         unsigned long dbr_w:1;
 459         unsigned long dbr_r:1;
 460 } dbr_mask_reg_t;
 461 
 462 typedef union {
 463         unsigned long  val;
 464         ibr_mask_reg_t ibr;
 465         dbr_mask_reg_t dbr;
 466 } dbreg_t;
 467 
 468 
 469 /*
 470  * perfmon command descriptions
 471  */
 472 typedef struct {
 473         int             (*cmd_func)(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs);
 474         char            *cmd_name;
 475         int             cmd_flags;
 476         unsigned int    cmd_narg;
 477         size_t          cmd_argsize;
 478         int             (*cmd_getsize)(void *arg, size_t *sz);
 479 } pfm_cmd_desc_t;
 480 
 481 #define PFM_CMD_FD              0x01    /* command requires a file descriptor */
 482 #define PFM_CMD_ARG_READ        0x02    /* command must read argument(s) */
 483 #define PFM_CMD_ARG_RW          0x04    /* command must read/write argument(s) */
 484 #define PFM_CMD_STOP            0x08    /* command does not work on zombie context */
 485 
 486 
 487 #define PFM_CMD_NAME(cmd)       pfm_cmd_tab[(cmd)].cmd_name
 488 #define PFM_CMD_READ_ARG(cmd)   (pfm_cmd_tab[(cmd)].cmd_flags & PFM_CMD_ARG_READ)
 489 #define PFM_CMD_RW_ARG(cmd)     (pfm_cmd_tab[(cmd)].cmd_flags & PFM_CMD_ARG_RW)
 490 #define PFM_CMD_USE_FD(cmd)     (pfm_cmd_tab[(cmd)].cmd_flags & PFM_CMD_FD)
 491 #define PFM_CMD_STOPPED(cmd)    (pfm_cmd_tab[(cmd)].cmd_flags & PFM_CMD_STOP)
 492 
 493 #define PFM_CMD_ARG_MANY        -1 /* cannot be zero */
 494 
 495 typedef struct {
 496         unsigned long pfm_spurious_ovfl_intr_count;     /* keep track of spurious ovfl interrupts */
 497         unsigned long pfm_replay_ovfl_intr_count;       /* keep track of replayed ovfl interrupts */
 498         unsigned long pfm_ovfl_intr_count;              /* keep track of ovfl interrupts */
 499         unsigned long pfm_ovfl_intr_cycles;             /* cycles spent processing ovfl interrupts */
 500         unsigned long pfm_ovfl_intr_cycles_min;         /* min cycles spent processing ovfl interrupts */
 501         unsigned long pfm_ovfl_intr_cycles_max;         /* max cycles spent processing ovfl interrupts */
 502         unsigned long pfm_smpl_handler_calls;
 503         unsigned long pfm_smpl_handler_cycles;
 504         char pad[SMP_CACHE_BYTES] ____cacheline_aligned;
 505 } pfm_stats_t;
 506 
 507 /*
 508  * perfmon internal variables
 509  */
 510 static pfm_stats_t              pfm_stats[NR_CPUS];
 511 static pfm_session_t            pfm_sessions;   /* global sessions information */
 512 
 513 static DEFINE_SPINLOCK(pfm_alt_install_check);
 514 static pfm_intr_handler_desc_t  *pfm_alt_intr_handler;
 515 
 516 static struct proc_dir_entry    *perfmon_dir;
 517 static pfm_uuid_t               pfm_null_uuid = {0,};
 518 
 519 static spinlock_t               pfm_buffer_fmt_lock;
 520 static LIST_HEAD(pfm_buffer_fmt_list);
 521 
 522 static pmu_config_t             *pmu_conf;
 523 
 524 /* sysctl() controls */
 525 pfm_sysctl_t pfm_sysctl;
 526 EXPORT_SYMBOL(pfm_sysctl);
 527 
 528 static struct ctl_table pfm_ctl_table[] = {
 529         {
 530                 .procname       = "debug",
 531                 .data           = &pfm_sysctl.debug,
 532                 .maxlen         = sizeof(int),
 533                 .mode           = 0666,
 534                 .proc_handler   = proc_dointvec,
 535         },
 536         {
 537                 .procname       = "debug_ovfl",
 538                 .data           = &pfm_sysctl.debug_ovfl,
 539                 .maxlen         = sizeof(int),
 540                 .mode           = 0666,
 541                 .proc_handler   = proc_dointvec,
 542         },
 543         {
 544                 .procname       = "fastctxsw",
 545                 .data           = &pfm_sysctl.fastctxsw,
 546                 .maxlen         = sizeof(int),
 547                 .mode           = 0600,
 548                 .proc_handler   = proc_dointvec,
 549         },
 550         {
 551                 .procname       = "expert_mode",
 552                 .data           = &pfm_sysctl.expert_mode,
 553                 .maxlen         = sizeof(int),
 554                 .mode           = 0600,
 555                 .proc_handler   = proc_dointvec,
 556         },
 557         {}
 558 };
 559 static struct ctl_table pfm_sysctl_dir[] = {
 560         {
 561                 .procname       = "perfmon",
 562                 .mode           = 0555,
 563                 .child          = pfm_ctl_table,
 564         },
 565         {}
 566 };
 567 static struct ctl_table pfm_sysctl_root[] = {
 568         {
 569                 .procname       = "kernel",
 570                 .mode           = 0555,
 571                 .child          = pfm_sysctl_dir,
 572         },
 573         {}
 574 };
 575 static struct ctl_table_header *pfm_sysctl_header;
 576 
 577 static int pfm_context_unload(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs);
 578 
 579 #define pfm_get_cpu_var(v)              __ia64_per_cpu_var(v)
 580 #define pfm_get_cpu_data(a,b)           per_cpu(a, b)
 581 
 582 static inline void
 583 pfm_put_task(struct task_struct *task)
 584 {
 585         if (task != current) put_task_struct(task);
 586 }
 587 
 588 static inline unsigned long
 589 pfm_protect_ctx_ctxsw(pfm_context_t *x)
 590 {
 591         spin_lock(&(x)->ctx_lock);
 592         return 0UL;
 593 }
 594 
 595 static inline void
 596 pfm_unprotect_ctx_ctxsw(pfm_context_t *x, unsigned long f)
 597 {
 598         spin_unlock(&(x)->ctx_lock);
 599 }
 600 
 601 /* forward declaration */
 602 static const struct dentry_operations pfmfs_dentry_operations;
 603 
 604 static int pfmfs_init_fs_context(struct fs_context *fc)
 605 {
 606         struct pseudo_fs_context *ctx = init_pseudo(fc, PFMFS_MAGIC);
 607         if (!ctx)
 608                 return -ENOMEM;
 609         ctx->dops = &pfmfs_dentry_operations;
 610         return 0;
 611 }
 612 
 613 static struct file_system_type pfm_fs_type = {
 614         .name                   = "pfmfs",
 615         .init_fs_context        = pfmfs_init_fs_context,
 616         .kill_sb                = kill_anon_super,
 617 };
 618 MODULE_ALIAS_FS("pfmfs");
 619 
 620 DEFINE_PER_CPU(unsigned long, pfm_syst_info);
 621 DEFINE_PER_CPU(struct task_struct *, pmu_owner);
 622 DEFINE_PER_CPU(pfm_context_t  *, pmu_ctx);
 623 DEFINE_PER_CPU(unsigned long, pmu_activation_number);
 624 EXPORT_PER_CPU_SYMBOL_GPL(pfm_syst_info);
 625 
 626 
 627 /* forward declaration */
 628 static const struct file_operations pfm_file_ops;
 629 
 630 /*
 631  * forward declarations
 632  */
 633 #ifndef CONFIG_SMP
 634 static void pfm_lazy_save_regs (struct task_struct *ta);
 635 #endif
 636 
 637 void dump_pmu_state(const char *);
 638 static int pfm_write_ibr_dbr(int mode, pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs);
 639 
 640 #include "perfmon_itanium.h"
 641 #include "perfmon_mckinley.h"
 642 #include "perfmon_montecito.h"
 643 #include "perfmon_generic.h"
 644 
 645 static pmu_config_t *pmu_confs[]={
 646         &pmu_conf_mont,
 647         &pmu_conf_mck,
 648         &pmu_conf_ita,
 649         &pmu_conf_gen, /* must be last */
 650         NULL
 651 };
 652 
 653 
 654 static int pfm_end_notify_user(pfm_context_t *ctx);
 655 
 656 static inline void
 657 pfm_clear_psr_pp(void)
 658 {
 659         ia64_rsm(IA64_PSR_PP);
 660         ia64_srlz_i();
 661 }
 662 
 663 static inline void
 664 pfm_set_psr_pp(void)
 665 {
 666         ia64_ssm(IA64_PSR_PP);
 667         ia64_srlz_i();
 668 }
 669 
 670 static inline void
 671 pfm_clear_psr_up(void)
 672 {
 673         ia64_rsm(IA64_PSR_UP);
 674         ia64_srlz_i();
 675 }
 676 
 677 static inline void
 678 pfm_set_psr_up(void)
 679 {
 680         ia64_ssm(IA64_PSR_UP);
 681         ia64_srlz_i();
 682 }
 683 
 684 static inline unsigned long
 685 pfm_get_psr(void)
 686 {
 687         unsigned long tmp;
 688         tmp = ia64_getreg(_IA64_REG_PSR);
 689         ia64_srlz_i();
 690         return tmp;
 691 }
 692 
 693 static inline void
 694 pfm_set_psr_l(unsigned long val)
 695 {
 696         ia64_setreg(_IA64_REG_PSR_L, val);
 697         ia64_srlz_i();
 698 }
 699 
 700 static inline void
 701 pfm_freeze_pmu(void)
 702 {
 703         ia64_set_pmc(0,1UL);
 704         ia64_srlz_d();
 705 }
 706 
 707 static inline void
 708 pfm_unfreeze_pmu(void)
 709 {
 710         ia64_set_pmc(0,0UL);
 711         ia64_srlz_d();
 712 }
 713 
 714 static inline void
 715 pfm_restore_ibrs(unsigned long *ibrs, unsigned int nibrs)
 716 {
 717         int i;
 718 
 719         for (i=0; i < nibrs; i++) {
 720                 ia64_set_ibr(i, ibrs[i]);
 721                 ia64_dv_serialize_instruction();
 722         }
 723         ia64_srlz_i();
 724 }
 725 
 726 static inline void
 727 pfm_restore_dbrs(unsigned long *dbrs, unsigned int ndbrs)
 728 {
 729         int i;
 730 
 731         for (i=0; i < ndbrs; i++) {
 732                 ia64_set_dbr(i, dbrs[i]);
 733                 ia64_dv_serialize_data();
 734         }
 735         ia64_srlz_d();
 736 }
 737 
 738 /*
 739  * PMD[i] must be a counter. no check is made
 740  */
 741 static inline unsigned long
 742 pfm_read_soft_counter(pfm_context_t *ctx, int i)
 743 {
 744         return ctx->ctx_pmds[i].val + (ia64_get_pmd(i) & pmu_conf->ovfl_val);
 745 }
 746 
 747 /*
 748  * PMD[i] must be a counter. no check is made
 749  */
 750 static inline void
 751 pfm_write_soft_counter(pfm_context_t *ctx, int i, unsigned long val)
 752 {
 753         unsigned long ovfl_val = pmu_conf->ovfl_val;
 754 
 755         ctx->ctx_pmds[i].val = val  & ~ovfl_val;
 756         /*
 757          * writing to unimplemented part is ignore, so we do not need to
 758          * mask off top part
 759          */
 760         ia64_set_pmd(i, val & ovfl_val);
 761 }
 762 
 763 static pfm_msg_t *
 764 pfm_get_new_msg(pfm_context_t *ctx)
 765 {
 766         int idx, next;
 767 
 768         next = (ctx->ctx_msgq_tail+1) % PFM_MAX_MSGS;
 769 
 770         DPRINT(("ctx_fd=%p head=%d tail=%d\n", ctx, ctx->ctx_msgq_head, ctx->ctx_msgq_tail));
 771         if (next == ctx->ctx_msgq_head) return NULL;
 772 
 773         idx =   ctx->ctx_msgq_tail;
 774         ctx->ctx_msgq_tail = next;
 775 
 776         DPRINT(("ctx=%p head=%d tail=%d msg=%d\n", ctx, ctx->ctx_msgq_head, ctx->ctx_msgq_tail, idx));
 777 
 778         return ctx->ctx_msgq+idx;
 779 }
 780 
 781 static pfm_msg_t *
 782 pfm_get_next_msg(pfm_context_t *ctx)
 783 {
 784         pfm_msg_t *msg;
 785 
 786         DPRINT(("ctx=%p head=%d tail=%d\n", ctx, ctx->ctx_msgq_head, ctx->ctx_msgq_tail));
 787 
 788         if (PFM_CTXQ_EMPTY(ctx)) return NULL;
 789 
 790         /*
 791          * get oldest message
 792          */
 793         msg = ctx->ctx_msgq+ctx->ctx_msgq_head;
 794 
 795         /*
 796          * and move forward
 797          */
 798         ctx->ctx_msgq_head = (ctx->ctx_msgq_head+1) % PFM_MAX_MSGS;
 799 
 800         DPRINT(("ctx=%p head=%d tail=%d type=%d\n", ctx, ctx->ctx_msgq_head, ctx->ctx_msgq_tail, msg->pfm_gen_msg.msg_type));
 801 
 802         return msg;
 803 }
 804 
 805 static void
 806 pfm_reset_msgq(pfm_context_t *ctx)
 807 {
 808         ctx->ctx_msgq_head = ctx->ctx_msgq_tail = 0;
 809         DPRINT(("ctx=%p msgq reset\n", ctx));
 810 }
 811 
 812 static pfm_context_t *
 813 pfm_context_alloc(int ctx_flags)
 814 {
 815         pfm_context_t *ctx;
 816 
 817         /* 
 818          * allocate context descriptor 
 819          * must be able to free with interrupts disabled
 820          */
 821         ctx = kzalloc(sizeof(pfm_context_t), GFP_KERNEL);
 822         if (ctx) {
 823                 DPRINT(("alloc ctx @%p\n", ctx));
 824 
 825                 /*
 826                  * init context protection lock
 827                  */
 828                 spin_lock_init(&ctx->ctx_lock);
 829 
 830                 /*
 831                  * context is unloaded
 832                  */
 833                 ctx->ctx_state = PFM_CTX_UNLOADED;
 834 
 835                 /*
 836                  * initialization of context's flags
 837                  */
 838                 ctx->ctx_fl_block       = (ctx_flags & PFM_FL_NOTIFY_BLOCK) ? 1 : 0;
 839                 ctx->ctx_fl_system      = (ctx_flags & PFM_FL_SYSTEM_WIDE) ? 1: 0;
 840                 ctx->ctx_fl_no_msg      = (ctx_flags & PFM_FL_OVFL_NO_MSG) ? 1: 0;
 841                 /*
 842                  * will move to set properties
 843                  * ctx->ctx_fl_excl_idle   = (ctx_flags & PFM_FL_EXCL_IDLE) ? 1: 0;
 844                  */
 845 
 846                 /*
 847                  * init restart semaphore to locked
 848                  */
 849                 init_completion(&ctx->ctx_restart_done);
 850 
 851                 /*
 852                  * activation is used in SMP only
 853                  */
 854                 ctx->ctx_last_activation = PFM_INVALID_ACTIVATION;
 855                 SET_LAST_CPU(ctx, -1);
 856 
 857                 /*
 858                  * initialize notification message queue
 859                  */
 860                 ctx->ctx_msgq_head = ctx->ctx_msgq_tail = 0;
 861                 init_waitqueue_head(&ctx->ctx_msgq_wait);
 862                 init_waitqueue_head(&ctx->ctx_zombieq);
 863 
 864         }
 865         return ctx;
 866 }
 867 
 868 static void
 869 pfm_context_free(pfm_context_t *ctx)
 870 {
 871         if (ctx) {
 872                 DPRINT(("free ctx @%p\n", ctx));
 873                 kfree(ctx);
 874         }
 875 }
 876 
 877 static void
 878 pfm_mask_monitoring(struct task_struct *task)
 879 {
 880         pfm_context_t *ctx = PFM_GET_CTX(task);
 881         unsigned long mask, val, ovfl_mask;
 882         int i;
 883 
 884         DPRINT_ovfl(("masking monitoring for [%d]\n", task_pid_nr(task)));
 885 
 886         ovfl_mask = pmu_conf->ovfl_val;
 887         /*
 888          * monitoring can only be masked as a result of a valid
 889          * counter overflow. In UP, it means that the PMU still
 890          * has an owner. Note that the owner can be different
 891          * from the current task. However the PMU state belongs
 892          * to the owner.
 893          * In SMP, a valid overflow only happens when task is
 894          * current. Therefore if we come here, we know that
 895          * the PMU state belongs to the current task, therefore
 896          * we can access the live registers.
 897          *
 898          * So in both cases, the live register contains the owner's
 899          * state. We can ONLY touch the PMU registers and NOT the PSR.
 900          *
 901          * As a consequence to this call, the ctx->th_pmds[] array
 902          * contains stale information which must be ignored
 903          * when context is reloaded AND monitoring is active (see
 904          * pfm_restart).
 905          */
 906         mask = ctx->ctx_used_pmds[0];
 907         for (i = 0; mask; i++, mask>>=1) {
 908                 /* skip non used pmds */
 909                 if ((mask & 0x1) == 0) continue;
 910                 val = ia64_get_pmd(i);
 911 
 912                 if (PMD_IS_COUNTING(i)) {
 913                         /*
 914                          * we rebuild the full 64 bit value of the counter
 915                          */
 916                         ctx->ctx_pmds[i].val += (val & ovfl_mask);
 917                 } else {
 918                         ctx->ctx_pmds[i].val = val;
 919                 }
 920                 DPRINT_ovfl(("pmd[%d]=0x%lx hw_pmd=0x%lx\n",
 921                         i,
 922                         ctx->ctx_pmds[i].val,
 923                         val & ovfl_mask));
 924         }
 925         /*
 926          * mask monitoring by setting the privilege level to 0
 927          * we cannot use psr.pp/psr.up for this, it is controlled by
 928          * the user
 929          *
 930          * if task is current, modify actual registers, otherwise modify
 931          * thread save state, i.e., what will be restored in pfm_load_regs()
 932          */
 933         mask = ctx->ctx_used_monitors[0] >> PMU_FIRST_COUNTER;
 934         for(i= PMU_FIRST_COUNTER; mask; i++, mask>>=1) {
 935                 if ((mask & 0x1) == 0UL) continue;
 936                 ia64_set_pmc(i, ctx->th_pmcs[i] & ~0xfUL);
 937                 ctx->th_pmcs[i] &= ~0xfUL;
 938                 DPRINT_ovfl(("pmc[%d]=0x%lx\n", i, ctx->th_pmcs[i]));
 939         }
 940         /*
 941          * make all of this visible
 942          */
 943         ia64_srlz_d();
 944 }
 945 
 946 /*
 947  * must always be done with task == current
 948  *
 949  * context must be in MASKED state when calling
 950  */
 951 static void
 952 pfm_restore_monitoring(struct task_struct *task)
 953 {
 954         pfm_context_t *ctx = PFM_GET_CTX(task);
 955         unsigned long mask, ovfl_mask;
 956         unsigned long psr, val;
 957         int i, is_system;
 958 
 959         is_system = ctx->ctx_fl_system;
 960         ovfl_mask = pmu_conf->ovfl_val;
 961 
 962         if (task != current) {
 963                 printk(KERN_ERR "perfmon.%d: invalid task[%d] current[%d]\n", __LINE__, task_pid_nr(task), task_pid_nr(current));
 964                 return;
 965         }
 966         if (ctx->ctx_state != PFM_CTX_MASKED) {
 967                 printk(KERN_ERR "perfmon.%d: task[%d] current[%d] invalid state=%d\n", __LINE__,
 968                         task_pid_nr(task), task_pid_nr(current), ctx->ctx_state);
 969                 return;
 970         }
 971         psr = pfm_get_psr();
 972         /*
 973          * monitoring is masked via the PMC.
 974          * As we restore their value, we do not want each counter to
 975          * restart right away. We stop monitoring using the PSR,
 976          * restore the PMC (and PMD) and then re-establish the psr
 977          * as it was. Note that there can be no pending overflow at
 978          * this point, because monitoring was MASKED.
 979          *
 980          * system-wide session are pinned and self-monitoring
 981          */
 982         if (is_system && (PFM_CPUINFO_GET() & PFM_CPUINFO_DCR_PP)) {
 983                 /* disable dcr pp */
 984                 ia64_setreg(_IA64_REG_CR_DCR, ia64_getreg(_IA64_REG_CR_DCR) & ~IA64_DCR_PP);
 985                 pfm_clear_psr_pp();
 986         } else {
 987                 pfm_clear_psr_up();
 988         }
 989         /*
 990          * first, we restore the PMD
 991          */
 992         mask = ctx->ctx_used_pmds[0];
 993         for (i = 0; mask; i++, mask>>=1) {
 994                 /* skip non used pmds */
 995                 if ((mask & 0x1) == 0) continue;
 996 
 997                 if (PMD_IS_COUNTING(i)) {
 998                         /*
 999                          * we split the 64bit value according to
1000                          * counter width
1001                          */
1002                         val = ctx->ctx_pmds[i].val & ovfl_mask;
1003                         ctx->ctx_pmds[i].val &= ~ovfl_mask;
1004                 } else {
1005                         val = ctx->ctx_pmds[i].val;
1006                 }
1007                 ia64_set_pmd(i, val);
1008 
1009                 DPRINT(("pmd[%d]=0x%lx hw_pmd=0x%lx\n",
1010                         i,
1011                         ctx->ctx_pmds[i].val,
1012                         val));
1013         }
1014         /*
1015          * restore the PMCs
1016          */
1017         mask = ctx->ctx_used_monitors[0] >> PMU_FIRST_COUNTER;
1018         for(i= PMU_FIRST_COUNTER; mask; i++, mask>>=1) {
1019                 if ((mask & 0x1) == 0UL) continue;
1020                 ctx->th_pmcs[i] = ctx->ctx_pmcs[i];
1021                 ia64_set_pmc(i, ctx->th_pmcs[i]);
1022                 DPRINT(("[%d] pmc[%d]=0x%lx\n",
1023                                         task_pid_nr(task), i, ctx->th_pmcs[i]));
1024         }
1025         ia64_srlz_d();
1026 
1027         /*
1028          * must restore DBR/IBR because could be modified while masked
1029          * XXX: need to optimize 
1030          */
1031         if (ctx->ctx_fl_using_dbreg) {
1032                 pfm_restore_ibrs(ctx->ctx_ibrs, pmu_conf->num_ibrs);
1033                 pfm_restore_dbrs(ctx->ctx_dbrs, pmu_conf->num_dbrs);
1034         }
1035 
1036         /*
1037          * now restore PSR
1038          */
1039         if (is_system && (PFM_CPUINFO_GET() & PFM_CPUINFO_DCR_PP)) {
1040                 /* enable dcr pp */
1041                 ia64_setreg(_IA64_REG_CR_DCR, ia64_getreg(_IA64_REG_CR_DCR) | IA64_DCR_PP);
1042                 ia64_srlz_i();
1043         }
1044         pfm_set_psr_l(psr);
1045 }
1046 
1047 static inline void
1048 pfm_save_pmds(unsigned long *pmds, unsigned long mask)
1049 {
1050         int i;
1051 
1052         ia64_srlz_d();
1053 
1054         for (i=0; mask; i++, mask>>=1) {
1055                 if (mask & 0x1) pmds[i] = ia64_get_pmd(i);
1056         }
1057 }
1058 
1059 /*
1060  * reload from thread state (used for ctxw only)
1061  */
1062 static inline void
1063 pfm_restore_pmds(unsigned long *pmds, unsigned long mask)
1064 {
1065         int i;
1066         unsigned long val, ovfl_val = pmu_conf->ovfl_val;
1067 
1068         for (i=0; mask; i++, mask>>=1) {
1069                 if ((mask & 0x1) == 0) continue;
1070                 val = PMD_IS_COUNTING(i) ? pmds[i] & ovfl_val : pmds[i];
1071                 ia64_set_pmd(i, val);
1072         }
1073         ia64_srlz_d();
1074 }
1075 
1076 /*
1077  * propagate PMD from context to thread-state
1078  */
1079 static inline void
1080 pfm_copy_pmds(struct task_struct *task, pfm_context_t *ctx)
1081 {
1082         unsigned long ovfl_val = pmu_conf->ovfl_val;
1083         unsigned long mask = ctx->ctx_all_pmds[0];
1084         unsigned long val;
1085         int i;
1086 
1087         DPRINT(("mask=0x%lx\n", mask));
1088 
1089         for (i=0; mask; i++, mask>>=1) {
1090 
1091                 val = ctx->ctx_pmds[i].val;
1092 
1093                 /*
1094                  * We break up the 64 bit value into 2 pieces
1095                  * the lower bits go to the machine state in the
1096                  * thread (will be reloaded on ctxsw in).
1097                  * The upper part stays in the soft-counter.
1098                  */
1099                 if (PMD_IS_COUNTING(i)) {
1100                         ctx->ctx_pmds[i].val = val & ~ovfl_val;
1101                          val &= ovfl_val;
1102                 }
1103                 ctx->th_pmds[i] = val;
1104 
1105                 DPRINT(("pmd[%d]=0x%lx soft_val=0x%lx\n",
1106                         i,
1107                         ctx->th_pmds[i],
1108                         ctx->ctx_pmds[i].val));
1109         }
1110 }
1111 
1112 /*
1113  * propagate PMC from context to thread-state
1114  */
1115 static inline void
1116 pfm_copy_pmcs(struct task_struct *task, pfm_context_t *ctx)
1117 {
1118         unsigned long mask = ctx->ctx_all_pmcs[0];
1119         int i;
1120 
1121         DPRINT(("mask=0x%lx\n", mask));
1122 
1123         for (i=0; mask; i++, mask>>=1) {
1124                 /* masking 0 with ovfl_val yields 0 */
1125                 ctx->th_pmcs[i] = ctx->ctx_pmcs[i];
1126                 DPRINT(("pmc[%d]=0x%lx\n", i, ctx->th_pmcs[i]));
1127         }
1128 }
1129 
1130 
1131 
1132 static inline void
1133 pfm_restore_pmcs(unsigned long *pmcs, unsigned long mask)
1134 {
1135         int i;
1136 
1137         for (i=0; mask; i++, mask>>=1) {
1138                 if ((mask & 0x1) == 0) continue;
1139                 ia64_set_pmc(i, pmcs[i]);
1140         }
1141         ia64_srlz_d();
1142 }
1143 
1144 static inline int
1145 pfm_uuid_cmp(pfm_uuid_t a, pfm_uuid_t b)
1146 {
1147         return memcmp(a, b, sizeof(pfm_uuid_t));
1148 }
1149 
1150 static inline int
1151 pfm_buf_fmt_exit(pfm_buffer_fmt_t *fmt, struct task_struct *task, void *buf, struct pt_regs *regs)
1152 {
1153         int ret = 0;
1154         if (fmt->fmt_exit) ret = (*fmt->fmt_exit)(task, buf, regs);
1155         return ret;
1156 }
1157 
1158 static inline int
1159 pfm_buf_fmt_getsize(pfm_buffer_fmt_t *fmt, struct task_struct *task, unsigned int flags, int cpu, void *arg, unsigned long *size)
1160 {
1161         int ret = 0;
1162         if (fmt->fmt_getsize) ret = (*fmt->fmt_getsize)(task, flags, cpu, arg, size);
1163         return ret;
1164 }
1165 
1166 
1167 static inline int
1168 pfm_buf_fmt_validate(pfm_buffer_fmt_t *fmt, struct task_struct *task, unsigned int flags,
1169                      int cpu, void *arg)
1170 {
1171         int ret = 0;
1172         if (fmt->fmt_validate) ret = (*fmt->fmt_validate)(task, flags, cpu, arg);
1173         return ret;
1174 }
1175 
1176 static inline int
1177 pfm_buf_fmt_init(pfm_buffer_fmt_t *fmt, struct task_struct *task, void *buf, unsigned int flags,
1178                      int cpu, void *arg)
1179 {
1180         int ret = 0;
1181         if (fmt->fmt_init) ret = (*fmt->fmt_init)(task, buf, flags, cpu, arg);
1182         return ret;
1183 }
1184 
1185 static inline int
1186 pfm_buf_fmt_restart(pfm_buffer_fmt_t *fmt, struct task_struct *task, pfm_ovfl_ctrl_t *ctrl, void *buf, struct pt_regs *regs)
1187 {
1188         int ret = 0;
1189         if (fmt->fmt_restart) ret = (*fmt->fmt_restart)(task, ctrl, buf, regs);
1190         return ret;
1191 }
1192 
1193 static inline int
1194 pfm_buf_fmt_restart_active(pfm_buffer_fmt_t *fmt, struct task_struct *task, pfm_ovfl_ctrl_t *ctrl, void *buf, struct pt_regs *regs)
1195 {
1196         int ret = 0;
1197         if (fmt->fmt_restart_active) ret = (*fmt->fmt_restart_active)(task, ctrl, buf, regs);
1198         return ret;
1199 }
1200 
1201 static pfm_buffer_fmt_t *
1202 __pfm_find_buffer_fmt(pfm_uuid_t uuid)
1203 {
1204         struct list_head * pos;
1205         pfm_buffer_fmt_t * entry;
1206 
1207         list_for_each(pos, &pfm_buffer_fmt_list) {
1208                 entry = list_entry(pos, pfm_buffer_fmt_t, fmt_list);
1209                 if (pfm_uuid_cmp(uuid, entry->fmt_uuid) == 0)
1210                         return entry;
1211         }
1212         return NULL;
1213 }
1214  
1215 /*
1216  * find a buffer format based on its uuid
1217  */
1218 static pfm_buffer_fmt_t *
1219 pfm_find_buffer_fmt(pfm_uuid_t uuid)
1220 {
1221         pfm_buffer_fmt_t * fmt;
1222         spin_lock(&pfm_buffer_fmt_lock);
1223         fmt = __pfm_find_buffer_fmt(uuid);
1224         spin_unlock(&pfm_buffer_fmt_lock);
1225         return fmt;
1226 }
1227  
1228 int
1229 pfm_register_buffer_fmt(pfm_buffer_fmt_t *fmt)
1230 {
1231         int ret = 0;
1232 
1233         /* some sanity checks */
1234         if (fmt == NULL || fmt->fmt_name == NULL) return -EINVAL;
1235 
1236         /* we need at least a handler */
1237         if (fmt->fmt_handler == NULL) return -EINVAL;
1238 
1239         /*
1240          * XXX: need check validity of fmt_arg_size
1241          */
1242 
1243         spin_lock(&pfm_buffer_fmt_lock);
1244 
1245         if (__pfm_find_buffer_fmt(fmt->fmt_uuid)) {
1246                 printk(KERN_ERR "perfmon: duplicate sampling format: %s\n", fmt->fmt_name);
1247                 ret = -EBUSY;
1248                 goto out;
1249         } 
1250         list_add(&fmt->fmt_list, &pfm_buffer_fmt_list);
1251         printk(KERN_INFO "perfmon: added sampling format %s\n", fmt->fmt_name);
1252 
1253 out:
1254         spin_unlock(&pfm_buffer_fmt_lock);
1255         return ret;
1256 }
1257 EXPORT_SYMBOL(pfm_register_buffer_fmt);
1258 
1259 int
1260 pfm_unregister_buffer_fmt(pfm_uuid_t uuid)
1261 {
1262         pfm_buffer_fmt_t *fmt;
1263         int ret = 0;
1264 
1265         spin_lock(&pfm_buffer_fmt_lock);
1266 
1267         fmt = __pfm_find_buffer_fmt(uuid);
1268         if (!fmt) {
1269                 printk(KERN_ERR "perfmon: cannot unregister format, not found\n");
1270                 ret = -EINVAL;
1271                 goto out;
1272         }
1273         list_del_init(&fmt->fmt_list);
1274         printk(KERN_INFO "perfmon: removed sampling format: %s\n", fmt->fmt_name);
1275 
1276 out:
1277         spin_unlock(&pfm_buffer_fmt_lock);
1278         return ret;
1279 
1280 }
1281 EXPORT_SYMBOL(pfm_unregister_buffer_fmt);
1282 
1283 static int
1284 pfm_reserve_session(struct task_struct *task, int is_syswide, unsigned int cpu)
1285 {
1286         unsigned long flags;
1287         /*
1288          * validity checks on cpu_mask have been done upstream
1289          */
1290         LOCK_PFS(flags);
1291 
1292         DPRINT(("in sys_sessions=%u task_sessions=%u dbregs=%u syswide=%d cpu=%u\n",
1293                 pfm_sessions.pfs_sys_sessions,
1294                 pfm_sessions.pfs_task_sessions,
1295                 pfm_sessions.pfs_sys_use_dbregs,
1296                 is_syswide,
1297                 cpu));
1298 
1299         if (is_syswide) {
1300                 /*
1301                  * cannot mix system wide and per-task sessions
1302                  */
1303                 if (pfm_sessions.pfs_task_sessions > 0UL) {
1304                         DPRINT(("system wide not possible, %u conflicting task_sessions\n",
1305                                 pfm_sessions.pfs_task_sessions));
1306                         goto abort;
1307                 }
1308 
1309                 if (pfm_sessions.pfs_sys_session[cpu]) goto error_conflict;
1310 
1311                 DPRINT(("reserving system wide session on CPU%u currently on CPU%u\n", cpu, smp_processor_id()));
1312 
1313                 pfm_sessions.pfs_sys_session[cpu] = task;
1314 
1315                 pfm_sessions.pfs_sys_sessions++ ;
1316 
1317         } else {
1318                 if (pfm_sessions.pfs_sys_sessions) goto abort;
1319                 pfm_sessions.pfs_task_sessions++;
1320         }
1321 
1322         DPRINT(("out sys_sessions=%u task_sessions=%u dbregs=%u syswide=%d cpu=%u\n",
1323                 pfm_sessions.pfs_sys_sessions,
1324                 pfm_sessions.pfs_task_sessions,
1325                 pfm_sessions.pfs_sys_use_dbregs,
1326                 is_syswide,
1327                 cpu));
1328 
1329         /*
1330          * Force idle() into poll mode
1331          */
1332         cpu_idle_poll_ctrl(true);
1333 
1334         UNLOCK_PFS(flags);
1335 
1336         return 0;
1337 
1338 error_conflict:
1339         DPRINT(("system wide not possible, conflicting session [%d] on CPU%d\n",
1340                 task_pid_nr(pfm_sessions.pfs_sys_session[cpu]),
1341                 cpu));
1342 abort:
1343         UNLOCK_PFS(flags);
1344 
1345         return -EBUSY;
1346 
1347 }
1348 
1349 static int
1350 pfm_unreserve_session(pfm_context_t *ctx, int is_syswide, unsigned int cpu)
1351 {
1352         unsigned long flags;
1353         /*
1354          * validity checks on cpu_mask have been done upstream
1355          */
1356         LOCK_PFS(flags);
1357 
1358         DPRINT(("in sys_sessions=%u task_sessions=%u dbregs=%u syswide=%d cpu=%u\n",
1359                 pfm_sessions.pfs_sys_sessions,
1360                 pfm_sessions.pfs_task_sessions,
1361                 pfm_sessions.pfs_sys_use_dbregs,
1362                 is_syswide,
1363                 cpu));
1364 
1365 
1366         if (is_syswide) {
1367                 pfm_sessions.pfs_sys_session[cpu] = NULL;
1368                 /*
1369                  * would not work with perfmon+more than one bit in cpu_mask
1370                  */
1371                 if (ctx && ctx->ctx_fl_using_dbreg) {
1372                         if (pfm_sessions.pfs_sys_use_dbregs == 0) {
1373                                 printk(KERN_ERR "perfmon: invalid release for ctx %p sys_use_dbregs=0\n", ctx);
1374                         } else {
1375                                 pfm_sessions.pfs_sys_use_dbregs--;
1376                         }
1377                 }
1378                 pfm_sessions.pfs_sys_sessions--;
1379         } else {
1380                 pfm_sessions.pfs_task_sessions--;
1381         }
1382         DPRINT(("out sys_sessions=%u task_sessions=%u dbregs=%u syswide=%d cpu=%u\n",
1383                 pfm_sessions.pfs_sys_sessions,
1384                 pfm_sessions.pfs_task_sessions,
1385                 pfm_sessions.pfs_sys_use_dbregs,
1386                 is_syswide,
1387                 cpu));
1388 
1389         /* Undo forced polling. Last session reenables pal_halt */
1390         cpu_idle_poll_ctrl(false);
1391 
1392         UNLOCK_PFS(flags);
1393 
1394         return 0;
1395 }
1396 
1397 /*
1398  * removes virtual mapping of the sampling buffer.
1399  * IMPORTANT: cannot be called with interrupts disable, e.g. inside
1400  * a PROTECT_CTX() section.
1401  */
1402 static int
1403 pfm_remove_smpl_mapping(void *vaddr, unsigned long size)
1404 {
1405         struct task_struct *task = current;
1406         int r;
1407 
1408         /* sanity checks */
1409         if (task->mm == NULL || size == 0UL || vaddr == NULL) {
1410                 printk(KERN_ERR "perfmon: pfm_remove_smpl_mapping [%d] invalid context mm=%p\n", task_pid_nr(task), task->mm);
1411                 return -EINVAL;
1412         }
1413 
1414         DPRINT(("smpl_vaddr=%p size=%lu\n", vaddr, size));
1415 
1416         /*
1417          * does the actual unmapping
1418          */
1419         r = vm_munmap((unsigned long)vaddr, size);
1420 
1421         if (r !=0) {
1422                 printk(KERN_ERR "perfmon: [%d] unable to unmap sampling buffer @%p size=%lu\n", task_pid_nr(task), vaddr, size);
1423         }
1424 
1425         DPRINT(("do_unmap(%p, %lu)=%d\n", vaddr, size, r));
1426 
1427         return 0;
1428 }
1429 
1430 /*
1431  * free actual physical storage used by sampling buffer
1432  */
1433 #if 0
1434 static int
1435 pfm_free_smpl_buffer(pfm_context_t *ctx)
1436 {
1437         pfm_buffer_fmt_t *fmt;
1438 
1439         if (ctx->ctx_smpl_hdr == NULL) goto invalid_free;
1440 
1441         /*
1442          * we won't use the buffer format anymore
1443          */
1444         fmt = ctx->ctx_buf_fmt;
1445 
1446         DPRINT(("sampling buffer @%p size %lu vaddr=%p\n",
1447                 ctx->ctx_smpl_hdr,
1448                 ctx->ctx_smpl_size,
1449                 ctx->ctx_smpl_vaddr));
1450 
1451         pfm_buf_fmt_exit(fmt, current, NULL, NULL);
1452 
1453         /*
1454          * free the buffer
1455          */
1456         vfree(ctx->ctx_smpl_hdr);
1457 
1458         ctx->ctx_smpl_hdr  = NULL;
1459         ctx->ctx_smpl_size = 0UL;
1460 
1461         return 0;
1462 
1463 invalid_free:
1464         printk(KERN_ERR "perfmon: pfm_free_smpl_buffer [%d] no buffer\n", task_pid_nr(current));
1465         return -EINVAL;
1466 }
1467 #endif
1468 
1469 static inline void
1470 pfm_exit_smpl_buffer(pfm_buffer_fmt_t *fmt)
1471 {
1472         if (fmt == NULL) return;
1473 
1474         pfm_buf_fmt_exit(fmt, current, NULL, NULL);
1475 
1476 }
1477 
1478 /*
1479  * pfmfs should _never_ be mounted by userland - too much of security hassle,
1480  * no real gain from having the whole whorehouse mounted. So we don't need
1481  * any operations on the root directory. However, we need a non-trivial
1482  * d_name - pfm: will go nicely and kill the special-casing in procfs.
1483  */
1484 static struct vfsmount *pfmfs_mnt __read_mostly;
1485 
1486 static int __init
1487 init_pfm_fs(void)
1488 {
1489         int err = register_filesystem(&pfm_fs_type);
1490         if (!err) {
1491                 pfmfs_mnt = kern_mount(&pfm_fs_type);
1492                 err = PTR_ERR(pfmfs_mnt);
1493                 if (IS_ERR(pfmfs_mnt))
1494                         unregister_filesystem(&pfm_fs_type);
1495                 else
1496                         err = 0;
1497         }
1498         return err;
1499 }
1500 
1501 static ssize_t
1502 pfm_read(struct file *filp, char __user *buf, size_t size, loff_t *ppos)
1503 {
1504         pfm_context_t *ctx;
1505         pfm_msg_t *msg;
1506         ssize_t ret;
1507         unsigned long flags;
1508         DECLARE_WAITQUEUE(wait, current);
1509         if (PFM_IS_FILE(filp) == 0) {
1510                 printk(KERN_ERR "perfmon: pfm_poll: bad magic [%d]\n", task_pid_nr(current));
1511                 return -EINVAL;
1512         }
1513 
1514         ctx = filp->private_data;
1515         if (ctx == NULL) {
1516                 printk(KERN_ERR "perfmon: pfm_read: NULL ctx [%d]\n", task_pid_nr(current));
1517                 return -EINVAL;
1518         }
1519 
1520         /*
1521          * check even when there is no message
1522          */
1523         if (size < sizeof(pfm_msg_t)) {
1524                 DPRINT(("message is too small ctx=%p (>=%ld)\n", ctx, sizeof(pfm_msg_t)));
1525                 return -EINVAL;
1526         }
1527 
1528         PROTECT_CTX(ctx, flags);
1529 
1530         /*
1531          * put ourselves on the wait queue
1532          */
1533         add_wait_queue(&ctx->ctx_msgq_wait, &wait);
1534 
1535 
1536         for(;;) {
1537                 /*
1538                  * check wait queue
1539                  */
1540 
1541                 set_current_state(TASK_INTERRUPTIBLE);
1542 
1543                 DPRINT(("head=%d tail=%d\n", ctx->ctx_msgq_head, ctx->ctx_msgq_tail));
1544 
1545                 ret = 0;
1546                 if(PFM_CTXQ_EMPTY(ctx) == 0) break;
1547 
1548                 UNPROTECT_CTX(ctx, flags);
1549 
1550                 /*
1551                  * check non-blocking read
1552                  */
1553                 ret = -EAGAIN;
1554                 if(filp->f_flags & O_NONBLOCK) break;
1555 
1556                 /*
1557                  * check pending signals
1558                  */
1559                 if(signal_pending(current)) {
1560                         ret = -EINTR;
1561                         break;
1562                 }
1563                 /*
1564                  * no message, so wait
1565                  */
1566                 schedule();
1567 
1568                 PROTECT_CTX(ctx, flags);
1569         }
1570         DPRINT(("[%d] back to running ret=%ld\n", task_pid_nr(current), ret));
1571         set_current_state(TASK_RUNNING);
1572         remove_wait_queue(&ctx->ctx_msgq_wait, &wait);
1573 
1574         if (ret < 0) goto abort;
1575 
1576         ret = -EINVAL;
1577         msg = pfm_get_next_msg(ctx);
1578         if (msg == NULL) {
1579                 printk(KERN_ERR "perfmon: pfm_read no msg for ctx=%p [%d]\n", ctx, task_pid_nr(current));
1580                 goto abort_locked;
1581         }
1582 
1583         DPRINT(("fd=%d type=%d\n", msg->pfm_gen_msg.msg_ctx_fd, msg->pfm_gen_msg.msg_type));
1584 
1585         ret = -EFAULT;
1586         if(copy_to_user(buf, msg, sizeof(pfm_msg_t)) == 0) ret = sizeof(pfm_msg_t);
1587 
1588 abort_locked:
1589         UNPROTECT_CTX(ctx, flags);
1590 abort:
1591         return ret;
1592 }
1593 
1594 static ssize_t
1595 pfm_write(struct file *file, const char __user *ubuf,
1596                           size_t size, loff_t *ppos)
1597 {
1598         DPRINT(("pfm_write called\n"));
1599         return -EINVAL;
1600 }
1601 
1602 static __poll_t
1603 pfm_poll(struct file *filp, poll_table * wait)
1604 {
1605         pfm_context_t *ctx;
1606         unsigned long flags;
1607         __poll_t mask = 0;
1608 
1609         if (PFM_IS_FILE(filp) == 0) {
1610                 printk(KERN_ERR "perfmon: pfm_poll: bad magic [%d]\n", task_pid_nr(current));
1611                 return 0;
1612         }
1613 
1614         ctx = filp->private_data;
1615         if (ctx == NULL) {
1616                 printk(KERN_ERR "perfmon: pfm_poll: NULL ctx [%d]\n", task_pid_nr(current));
1617                 return 0;
1618         }
1619 
1620 
1621         DPRINT(("pfm_poll ctx_fd=%d before poll_wait\n", ctx->ctx_fd));
1622 
1623         poll_wait(filp, &ctx->ctx_msgq_wait, wait);
1624 
1625         PROTECT_CTX(ctx, flags);
1626 
1627         if (PFM_CTXQ_EMPTY(ctx) == 0)
1628                 mask =  EPOLLIN | EPOLLRDNORM;
1629 
1630         UNPROTECT_CTX(ctx, flags);
1631 
1632         DPRINT(("pfm_poll ctx_fd=%d mask=0x%x\n", ctx->ctx_fd, mask));
1633 
1634         return mask;
1635 }
1636 
1637 static long
1638 pfm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1639 {
1640         DPRINT(("pfm_ioctl called\n"));
1641         return -EINVAL;
1642 }
1643 
1644 /*
1645  * interrupt cannot be masked when coming here
1646  */
1647 static inline int
1648 pfm_do_fasync(int fd, struct file *filp, pfm_context_t *ctx, int on)
1649 {
1650         int ret;
1651 
1652         ret = fasync_helper (fd, filp, on, &ctx->ctx_async_queue);
1653 
1654         DPRINT(("pfm_fasync called by [%d] on ctx_fd=%d on=%d async_queue=%p ret=%d\n",
1655                 task_pid_nr(current),
1656                 fd,
1657                 on,
1658                 ctx->ctx_async_queue, ret));
1659 
1660         return ret;
1661 }
1662 
1663 static int
1664 pfm_fasync(int fd, struct file *filp, int on)
1665 {
1666         pfm_context_t *ctx;
1667         int ret;
1668 
1669         if (PFM_IS_FILE(filp) == 0) {
1670                 printk(KERN_ERR "perfmon: pfm_fasync bad magic [%d]\n", task_pid_nr(current));
1671                 return -EBADF;
1672         }
1673 
1674         ctx = filp->private_data;
1675         if (ctx == NULL) {
1676                 printk(KERN_ERR "perfmon: pfm_fasync NULL ctx [%d]\n", task_pid_nr(current));
1677                 return -EBADF;
1678         }
1679         /*
1680          * we cannot mask interrupts during this call because this may
1681          * may go to sleep if memory is not readily avalaible.
1682          *
1683          * We are protected from the conetxt disappearing by the get_fd()/put_fd()
1684          * done in caller. Serialization of this function is ensured by caller.
1685          */
1686         ret = pfm_do_fasync(fd, filp, ctx, on);
1687 
1688 
1689         DPRINT(("pfm_fasync called on ctx_fd=%d on=%d async_queue=%p ret=%d\n",
1690                 fd,
1691                 on,
1692                 ctx->ctx_async_queue, ret));
1693 
1694         return ret;
1695 }
1696 
1697 #ifdef CONFIG_SMP
1698 /*
1699  * this function is exclusively called from pfm_close().
1700  * The context is not protected at that time, nor are interrupts
1701  * on the remote CPU. That's necessary to avoid deadlocks.
1702  */
1703 static void
1704 pfm_syswide_force_stop(void *info)
1705 {
1706         pfm_context_t   *ctx = (pfm_context_t *)info;
1707         struct pt_regs *regs = task_pt_regs(current);
1708         struct task_struct *owner;
1709         unsigned long flags;
1710         int ret;
1711 
1712         if (ctx->ctx_cpu != smp_processor_id()) {
1713                 printk(KERN_ERR "perfmon: pfm_syswide_force_stop for CPU%d  but on CPU%d\n",
1714                         ctx->ctx_cpu,
1715                         smp_processor_id());
1716                 return;
1717         }
1718         owner = GET_PMU_OWNER();
1719         if (owner != ctx->ctx_task) {
1720                 printk(KERN_ERR "perfmon: pfm_syswide_force_stop CPU%d unexpected owner [%d] instead of [%d]\n",
1721                         smp_processor_id(),
1722                         task_pid_nr(owner), task_pid_nr(ctx->ctx_task));
1723                 return;
1724         }
1725         if (GET_PMU_CTX() != ctx) {
1726                 printk(KERN_ERR "perfmon: pfm_syswide_force_stop CPU%d unexpected ctx %p instead of %p\n",
1727                         smp_processor_id(),
1728                         GET_PMU_CTX(), ctx);
1729                 return;
1730         }
1731 
1732         DPRINT(("on CPU%d forcing system wide stop for [%d]\n", smp_processor_id(), task_pid_nr(ctx->ctx_task)));
1733         /*
1734          * the context is already protected in pfm_close(), we simply
1735          * need to mask interrupts to avoid a PMU interrupt race on
1736          * this CPU
1737          */
1738         local_irq_save(flags);
1739 
1740         ret = pfm_context_unload(ctx, NULL, 0, regs);
1741         if (ret) {
1742                 DPRINT(("context_unload returned %d\n", ret));
1743         }
1744 
1745         /*
1746          * unmask interrupts, PMU interrupts are now spurious here
1747          */
1748         local_irq_restore(flags);
1749 }
1750 
1751 static void
1752 pfm_syswide_cleanup_other_cpu(pfm_context_t *ctx)
1753 {
1754         int ret;
1755 
1756         DPRINT(("calling CPU%d for cleanup\n", ctx->ctx_cpu));
1757         ret = smp_call_function_single(ctx->ctx_cpu, pfm_syswide_force_stop, ctx, 1);
1758         DPRINT(("called CPU%d for cleanup ret=%d\n", ctx->ctx_cpu, ret));
1759 }
1760 #endif /* CONFIG_SMP */
1761 
1762 /*
1763  * called for each close(). Partially free resources.
1764  * When caller is self-monitoring, the context is unloaded.
1765  */
1766 static int
1767 pfm_flush(struct file *filp, fl_owner_t id)
1768 {
1769         pfm_context_t *ctx;
1770         struct task_struct *task;
1771         struct pt_regs *regs;
1772         unsigned long flags;
1773         unsigned long smpl_buf_size = 0UL;
1774         void *smpl_buf_vaddr = NULL;
1775         int state, is_system;
1776 
1777         if (PFM_IS_FILE(filp) == 0) {
1778                 DPRINT(("bad magic for\n"));
1779                 return -EBADF;
1780         }
1781 
1782         ctx = filp->private_data;
1783         if (ctx == NULL) {
1784                 printk(KERN_ERR "perfmon: pfm_flush: NULL ctx [%d]\n", task_pid_nr(current));
1785                 return -EBADF;
1786         }
1787 
1788         /*
1789          * remove our file from the async queue, if we use this mode.
1790          * This can be done without the context being protected. We come
1791          * here when the context has become unreachable by other tasks.
1792          *
1793          * We may still have active monitoring at this point and we may
1794          * end up in pfm_overflow_handler(). However, fasync_helper()
1795          * operates with interrupts disabled and it cleans up the
1796          * queue. If the PMU handler is called prior to entering
1797          * fasync_helper() then it will send a signal. If it is
1798          * invoked after, it will find an empty queue and no
1799          * signal will be sent. In both case, we are safe
1800          */
1801         PROTECT_CTX(ctx, flags);
1802 
1803         state     = ctx->ctx_state;
1804         is_system = ctx->ctx_fl_system;
1805 
1806         task = PFM_CTX_TASK(ctx);
1807         regs = task_pt_regs(task);
1808 
1809         DPRINT(("ctx_state=%d is_current=%d\n",
1810                 state,
1811                 task == current ? 1 : 0));
1812 
1813         /*
1814          * if state == UNLOADED, then task is NULL
1815          */
1816 
1817         /*
1818          * we must stop and unload because we are losing access to the context.
1819          */
1820         if (task == current) {
1821 #ifdef CONFIG_SMP
1822                 /*
1823                  * the task IS the owner but it migrated to another CPU: that's bad
1824                  * but we must handle this cleanly. Unfortunately, the kernel does
1825                  * not provide a mechanism to block migration (while the context is loaded).
1826                  *
1827                  * We need to release the resource on the ORIGINAL cpu.
1828                  */
1829                 if (is_system && ctx->ctx_cpu != smp_processor_id()) {
1830 
1831                         DPRINT(("should be running on CPU%d\n", ctx->ctx_cpu));
1832                         /*
1833                          * keep context protected but unmask interrupt for IPI
1834                          */
1835                         local_irq_restore(flags);
1836 
1837                         pfm_syswide_cleanup_other_cpu(ctx);
1838 
1839                         /*
1840                          * restore interrupt masking
1841                          */
1842                         local_irq_save(flags);
1843 
1844                         /*
1845                          * context is unloaded at this point
1846                          */
1847                 } else
1848 #endif /* CONFIG_SMP */
1849                 {
1850 
1851                         DPRINT(("forcing unload\n"));
1852                         /*
1853                         * stop and unload, returning with state UNLOADED
1854                         * and session unreserved.
1855                         */
1856                         pfm_context_unload(ctx, NULL, 0, regs);
1857 
1858                         DPRINT(("ctx_state=%d\n", ctx->ctx_state));
1859                 }
1860         }
1861 
1862         /*
1863          * remove virtual mapping, if any, for the calling task.
1864          * cannot reset ctx field until last user is calling close().
1865          *
1866          * ctx_smpl_vaddr must never be cleared because it is needed
1867          * by every task with access to the context
1868          *
1869          * When called from do_exit(), the mm context is gone already, therefore
1870          * mm is NULL, i.e., the VMA is already gone  and we do not have to
1871          * do anything here
1872          */
1873         if (ctx->ctx_smpl_vaddr && current->mm) {
1874                 smpl_buf_vaddr = ctx->ctx_smpl_vaddr;
1875                 smpl_buf_size  = ctx->ctx_smpl_size;
1876         }
1877 
1878         UNPROTECT_CTX(ctx, flags);
1879 
1880         /*
1881          * if there was a mapping, then we systematically remove it
1882          * at this point. Cannot be done inside critical section
1883          * because some VM function reenables interrupts.
1884          *
1885          */
1886         if (smpl_buf_vaddr) pfm_remove_smpl_mapping(smpl_buf_vaddr, smpl_buf_size);
1887 
1888         return 0;
1889 }
1890 /*
1891  * called either on explicit close() or from exit_files(). 
1892  * Only the LAST user of the file gets to this point, i.e., it is
1893  * called only ONCE.
1894  *
1895  * IMPORTANT: we get called ONLY when the refcnt on the file gets to zero 
1896  * (fput()),i.e, last task to access the file. Nobody else can access the 
1897  * file at this point.
1898  *
1899  * When called from exit_files(), the VMA has been freed because exit_mm()
1900  * is executed before exit_files().
1901  *
1902  * When called from exit_files(), the current task is not yet ZOMBIE but we
1903  * flush the PMU state to the context. 
1904  */
1905 static int
1906 pfm_close(struct inode *inode, struct file *filp)
1907 {
1908         pfm_context_t *ctx;
1909         struct task_struct *task;
1910         struct pt_regs *regs;
1911         DECLARE_WAITQUEUE(wait, current);
1912         unsigned long flags;
1913         unsigned long smpl_buf_size = 0UL;
1914         void *smpl_buf_addr = NULL;
1915         int free_possible = 1;
1916         int state, is_system;
1917 
1918         DPRINT(("pfm_close called private=%p\n", filp->private_data));
1919 
1920         if (PFM_IS_FILE(filp) == 0) {
1921                 DPRINT(("bad magic\n"));
1922                 return -EBADF;
1923         }
1924         
1925         ctx = filp->private_data;
1926         if (ctx == NULL) {
1927                 printk(KERN_ERR "perfmon: pfm_close: NULL ctx [%d]\n", task_pid_nr(current));
1928                 return -EBADF;
1929         }
1930 
1931         PROTECT_CTX(ctx, flags);
1932 
1933         state     = ctx->ctx_state;
1934         is_system = ctx->ctx_fl_system;
1935 
1936         task = PFM_CTX_TASK(ctx);
1937         regs = task_pt_regs(task);
1938 
1939         DPRINT(("ctx_state=%d is_current=%d\n", 
1940                 state,
1941                 task == current ? 1 : 0));
1942 
1943         /*
1944          * if task == current, then pfm_flush() unloaded the context
1945          */
1946         if (state == PFM_CTX_UNLOADED) goto doit;
1947 
1948         /*
1949          * context is loaded/masked and task != current, we need to
1950          * either force an unload or go zombie
1951          */
1952 
1953         /*
1954          * The task is currently blocked or will block after an overflow.
1955          * we must force it to wakeup to get out of the
1956          * MASKED state and transition to the unloaded state by itself.
1957          *
1958          * This situation is only possible for per-task mode
1959          */
1960         if (state == PFM_CTX_MASKED && CTX_OVFL_NOBLOCK(ctx) == 0) {
1961 
1962                 /*
1963                  * set a "partial" zombie state to be checked
1964                  * upon return from down() in pfm_handle_work().
1965                  *
1966                  * We cannot use the ZOMBIE state, because it is checked
1967                  * by pfm_load_regs() which is called upon wakeup from down().
1968                  * In such case, it would free the context and then we would
1969                  * return to pfm_handle_work() which would access the
1970                  * stale context. Instead, we set a flag invisible to pfm_load_regs()
1971                  * but visible to pfm_handle_work().
1972                  *
1973                  * For some window of time, we have a zombie context with
1974                  * ctx_state = MASKED  and not ZOMBIE
1975                  */
1976                 ctx->ctx_fl_going_zombie = 1;
1977 
1978                 /*
1979                  * force task to wake up from MASKED state
1980                  */
1981                 complete(&ctx->ctx_restart_done);
1982 
1983                 DPRINT(("waking up ctx_state=%d\n", state));
1984 
1985                 /*
1986                  * put ourself to sleep waiting for the other
1987                  * task to report completion
1988                  *
1989                  * the context is protected by mutex, therefore there
1990                  * is no risk of being notified of completion before
1991                  * begin actually on the waitq.
1992                  */
1993                 set_current_state(TASK_INTERRUPTIBLE);
1994                 add_wait_queue(&ctx->ctx_zombieq, &wait);
1995 
1996                 UNPROTECT_CTX(ctx, flags);
1997 
1998                 /*
1999                  * XXX: check for signals :
2000                  *      - ok for explicit close
2001                  *      - not ok when coming from exit_files()
2002                  */
2003                 schedule();
2004 
2005 
2006                 PROTECT_CTX(ctx, flags);
2007 
2008 
2009                 remove_wait_queue(&ctx->ctx_zombieq, &wait);
2010                 set_current_state(TASK_RUNNING);
2011 
2012                 /*
2013                  * context is unloaded at this point
2014                  */
2015                 DPRINT(("after zombie wakeup ctx_state=%d for\n", state));
2016         }
2017         else if (task != current) {
2018 #ifdef CONFIG_SMP
2019                 /*
2020                  * switch context to zombie state
2021                  */
2022                 ctx->ctx_state = PFM_CTX_ZOMBIE;
2023 
2024                 DPRINT(("zombie ctx for [%d]\n", task_pid_nr(task)));
2025                 /*
2026                  * cannot free the context on the spot. deferred until
2027                  * the task notices the ZOMBIE state
2028                  */
2029                 free_possible = 0;
2030 #else
2031                 pfm_context_unload(ctx, NULL, 0, regs);
2032 #endif
2033         }
2034 
2035 doit:
2036         /* reload state, may have changed during  opening of critical section */
2037         state = ctx->ctx_state;
2038 
2039         /*
2040          * the context is still attached to a task (possibly current)
2041          * we cannot destroy it right now
2042          */
2043 
2044         /*
2045          * we must free the sampling buffer right here because
2046          * we cannot rely on it being cleaned up later by the
2047          * monitored task. It is not possible to free vmalloc'ed
2048          * memory in pfm_load_regs(). Instead, we remove the buffer
2049          * now. should there be subsequent PMU overflow originally
2050          * meant for sampling, the will be converted to spurious
2051          * and that's fine because the monitoring tools is gone anyway.
2052          */
2053         if (ctx->ctx_smpl_hdr) {
2054                 smpl_buf_addr = ctx->ctx_smpl_hdr;
2055                 smpl_buf_size = ctx->ctx_smpl_size;
2056                 /* no more sampling */
2057                 ctx->ctx_smpl_hdr = NULL;
2058                 ctx->ctx_fl_is_sampling = 0;
2059         }
2060 
2061         DPRINT(("ctx_state=%d free_possible=%d addr=%p size=%lu\n",
2062                 state,
2063                 free_possible,
2064                 smpl_buf_addr,
2065                 smpl_buf_size));
2066 
2067         if (smpl_buf_addr) pfm_exit_smpl_buffer(ctx->ctx_buf_fmt);
2068 
2069         /*
2070          * UNLOADED that the session has already been unreserved.
2071          */
2072         if (state == PFM_CTX_ZOMBIE) {
2073                 pfm_unreserve_session(ctx, ctx->ctx_fl_system , ctx->ctx_cpu);
2074         }
2075 
2076         /*
2077          * disconnect file descriptor from context must be done
2078          * before we unlock.
2079          */
2080         filp->private_data = NULL;
2081 
2082         /*
2083          * if we free on the spot, the context is now completely unreachable
2084          * from the callers side. The monitored task side is also cut, so we
2085          * can freely cut.
2086          *
2087          * If we have a deferred free, only the caller side is disconnected.
2088          */
2089         UNPROTECT_CTX(ctx, flags);
2090 
2091         /*
2092          * All memory free operations (especially for vmalloc'ed memory)
2093          * MUST be done with interrupts ENABLED.
2094          */
2095         vfree(smpl_buf_addr);
2096 
2097         /*
2098          * return the memory used by the context
2099          */
2100         if (free_possible) pfm_context_free(ctx);
2101 
2102         return 0;
2103 }
2104 
2105 static const struct file_operations pfm_file_ops = {
2106         .llseek         = no_llseek,
2107         .read           = pfm_read,
2108         .write          = pfm_write,
2109         .poll           = pfm_poll,
2110         .unlocked_ioctl = pfm_ioctl,
2111         .fasync         = pfm_fasync,
2112         .release        = pfm_close,
2113         .flush          = pfm_flush
2114 };
2115 
2116 static char *pfmfs_dname(struct dentry *dentry, char *buffer, int buflen)
2117 {
2118         return dynamic_dname(dentry, buffer, buflen, "pfm:[%lu]",
2119                              d_inode(dentry)->i_ino);
2120 }
2121 
2122 static const struct dentry_operations pfmfs_dentry_operations = {
2123         .d_delete = always_delete_dentry,
2124         .d_dname = pfmfs_dname,
2125 };
2126 
2127 
2128 static struct file *
2129 pfm_alloc_file(pfm_context_t *ctx)
2130 {
2131         struct file *file;
2132         struct inode *inode;
2133         struct path path;
2134         struct qstr this = { .name = "" };
2135 
2136         /*
2137          * allocate a new inode
2138          */
2139         inode = new_inode(pfmfs_mnt->mnt_sb);
2140         if (!inode)
2141                 return ERR_PTR(-ENOMEM);
2142 
2143         DPRINT(("new inode ino=%ld @%p\n", inode->i_ino, inode));
2144 
2145         inode->i_mode = S_IFCHR|S_IRUGO;
2146         inode->i_uid  = current_fsuid();
2147         inode->i_gid  = current_fsgid();
2148 
2149         /*
2150          * allocate a new dcache entry
2151          */
2152         path.dentry = d_alloc(pfmfs_mnt->mnt_root, &this);
2153         if (!path.dentry) {
2154                 iput(inode);
2155                 return ERR_PTR(-ENOMEM);
2156         }
2157         path.mnt = mntget(pfmfs_mnt);
2158 
2159         d_add(path.dentry, inode);
2160 
2161         file = alloc_file(&path, FMODE_READ, &pfm_file_ops);
2162         if (IS_ERR(file)) {
2163                 path_put(&path);
2164                 return file;
2165         }
2166 
2167         file->f_flags = O_RDONLY;
2168         file->private_data = ctx;
2169 
2170         return file;
2171 }
2172 
2173 static int
2174 pfm_remap_buffer(struct vm_area_struct *vma, unsigned long buf, unsigned long addr, unsigned long size)
2175 {
2176         DPRINT(("CPU%d buf=0x%lx addr=0x%lx size=%ld\n", smp_processor_id(), buf, addr, size));
2177 
2178         while (size > 0) {
2179                 unsigned long pfn = ia64_tpa(buf) >> PAGE_SHIFT;
2180 
2181 
2182                 if (remap_pfn_range(vma, addr, pfn, PAGE_SIZE, PAGE_READONLY))
2183                         return -ENOMEM;
2184 
2185                 addr  += PAGE_SIZE;
2186                 buf   += PAGE_SIZE;
2187                 size  -= PAGE_SIZE;
2188         }
2189         return 0;
2190 }
2191 
2192 /*
2193  * allocate a sampling buffer and remaps it into the user address space of the task
2194  */
2195 static int
2196 pfm_smpl_buffer_alloc(struct task_struct *task, struct file *filp, pfm_context_t *ctx, unsigned long rsize, void **user_vaddr)
2197 {
2198         struct mm_struct *mm = task->mm;
2199         struct vm_area_struct *vma = NULL;
2200         unsigned long size;
2201         void *smpl_buf;
2202 
2203 
2204         /*
2205          * the fixed header + requested size and align to page boundary
2206          */
2207         size = PAGE_ALIGN(rsize);
2208 
2209         DPRINT(("sampling buffer rsize=%lu size=%lu bytes\n", rsize, size));
2210 
2211         /*
2212          * check requested size to avoid Denial-of-service attacks
2213          * XXX: may have to refine this test
2214          * Check against address space limit.
2215          *
2216          * if ((mm->total_vm << PAGE_SHIFT) + len> task->rlim[RLIMIT_AS].rlim_cur)
2217          *      return -ENOMEM;
2218          */
2219         if (size > task_rlimit(task, RLIMIT_MEMLOCK))
2220                 return -ENOMEM;
2221 
2222         /*
2223          * We do the easy to undo allocations first.
2224          */
2225         smpl_buf = vzalloc(size);
2226         if (smpl_buf == NULL) {
2227                 DPRINT(("Can't allocate sampling buffer\n"));
2228                 return -ENOMEM;
2229         }
2230 
2231         DPRINT(("smpl_buf @%p\n", smpl_buf));
2232 
2233         /* allocate vma */
2234         vma = vm_area_alloc(mm);
2235         if (!vma) {
2236                 DPRINT(("Cannot allocate vma\n"));
2237                 goto error_kmem;
2238         }
2239 
2240         /*
2241          * partially initialize the vma for the sampling buffer
2242          */
2243         vma->vm_file         = get_file(filp);
2244         vma->vm_flags        = VM_READ|VM_MAYREAD|VM_DONTEXPAND|VM_DONTDUMP;
2245         vma->vm_page_prot    = PAGE_READONLY; /* XXX may need to change */
2246 
2247         /*
2248          * Now we have everything we need and we can initialize
2249          * and connect all the data structures
2250          */
2251 
2252         ctx->ctx_smpl_hdr   = smpl_buf;
2253         ctx->ctx_smpl_size  = size; /* aligned size */
2254 
2255         /*
2256          * Let's do the difficult operations next.
2257          *
2258          * now we atomically find some area in the address space and
2259          * remap the buffer in it.
2260          */
2261         down_write(&task->mm->mmap_sem);
2262 
2263         /* find some free area in address space, must have mmap sem held */
2264         vma->vm_start = get_unmapped_area(NULL, 0, size, 0, MAP_PRIVATE|MAP_ANONYMOUS);
2265         if (IS_ERR_VALUE(vma->vm_start)) {
2266                 DPRINT(("Cannot find unmapped area for size %ld\n", size));
2267                 up_write(&task->mm->mmap_sem);
2268                 goto error;
2269         }
2270         vma->vm_end = vma->vm_start + size;
2271         vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
2272 
2273         DPRINT(("aligned size=%ld, hdr=%p mapped @0x%lx\n", size, ctx->ctx_smpl_hdr, vma->vm_start));
2274 
2275         /* can only be applied to current task, need to have the mm semaphore held when called */
2276         if (pfm_remap_buffer(vma, (unsigned long)smpl_buf, vma->vm_start, size)) {
2277                 DPRINT(("Can't remap buffer\n"));
2278                 up_write(&task->mm->mmap_sem);
2279                 goto error;
2280         }
2281 
2282         /*
2283          * now insert the vma in the vm list for the process, must be
2284          * done with mmap lock held
2285          */
2286         insert_vm_struct(mm, vma);
2287 
2288         vm_stat_account(vma->vm_mm, vma->vm_flags, vma_pages(vma));
2289         up_write(&task->mm->mmap_sem);
2290 
2291         /*
2292          * keep track of user level virtual address
2293          */
2294         ctx->ctx_smpl_vaddr = (void *)vma->vm_start;
2295         *(unsigned long *)user_vaddr = vma->vm_start;
2296 
2297         return 0;
2298 
2299 error:
2300         vm_area_free(vma);
2301 error_kmem:
2302         vfree(smpl_buf);
2303 
2304         return -ENOMEM;
2305 }
2306 
2307 /*
2308  * XXX: do something better here
2309  */
2310 static int
2311 pfm_bad_permissions(struct task_struct *task)
2312 {
2313         const struct cred *tcred;
2314         kuid_t uid = current_uid();
2315         kgid_t gid = current_gid();
2316         int ret;
2317 
2318         rcu_read_lock();
2319         tcred = __task_cred(task);
2320 
2321         /* inspired by ptrace_attach() */
2322         DPRINT(("cur: uid=%d gid=%d task: euid=%d suid=%d uid=%d egid=%d sgid=%d\n",
2323                 from_kuid(&init_user_ns, uid),
2324                 from_kgid(&init_user_ns, gid),
2325                 from_kuid(&init_user_ns, tcred->euid),
2326                 from_kuid(&init_user_ns, tcred->suid),
2327                 from_kuid(&init_user_ns, tcred->uid),
2328                 from_kgid(&init_user_ns, tcred->egid),
2329                 from_kgid(&init_user_ns, tcred->sgid)));
2330 
2331         ret = ((!uid_eq(uid, tcred->euid))
2332                || (!uid_eq(uid, tcred->suid))
2333                || (!uid_eq(uid, tcred->uid))
2334                || (!gid_eq(gid, tcred->egid))
2335                || (!gid_eq(gid, tcred->sgid))
2336                || (!gid_eq(gid, tcred->gid))) && !capable(CAP_SYS_PTRACE);
2337 
2338         rcu_read_unlock();
2339         return ret;
2340 }
2341 
2342 static int
2343 pfarg_is_sane(struct task_struct *task, pfarg_context_t *pfx)
2344 {
2345         int ctx_flags;
2346 
2347         /* valid signal */
2348 
2349         ctx_flags = pfx->ctx_flags;
2350 
2351         if (ctx_flags & PFM_FL_SYSTEM_WIDE) {
2352 
2353                 /*
2354                  * cannot block in this mode
2355                  */
2356                 if (ctx_flags & PFM_FL_NOTIFY_BLOCK) {
2357                         DPRINT(("cannot use blocking mode when in system wide monitoring\n"));
2358                         return -EINVAL;
2359                 }
2360         } else {
2361         }
2362         /* probably more to add here */
2363 
2364         return 0;
2365 }
2366 
2367 static int
2368 pfm_setup_buffer_fmt(struct task_struct *task, struct file *filp, pfm_context_t *ctx, unsigned int ctx_flags,
2369                      unsigned int cpu, pfarg_context_t *arg)
2370 {
2371         pfm_buffer_fmt_t *fmt = NULL;
2372         unsigned long size = 0UL;
2373         void *uaddr = NULL;
2374         void *fmt_arg = NULL;
2375         int ret = 0;
2376 #define PFM_CTXARG_BUF_ARG(a)   (pfm_buffer_fmt_t *)(a+1)
2377 
2378         /* invoke and lock buffer format, if found */
2379         fmt = pfm_find_buffer_fmt(arg->ctx_smpl_buf_id);
2380         if (fmt == NULL) {
2381                 DPRINT(("[%d] cannot find buffer format\n", task_pid_nr(task)));
2382                 return -EINVAL;
2383         }
2384 
2385         /*
2386          * buffer argument MUST be contiguous to pfarg_context_t
2387          */
2388         if (fmt->fmt_arg_size) fmt_arg = PFM_CTXARG_BUF_ARG(arg);
2389 
2390         ret = pfm_buf_fmt_validate(fmt, task, ctx_flags, cpu, fmt_arg);
2391 
2392         DPRINT(("[%d] after validate(0x%x,%d,%p)=%d\n", task_pid_nr(task), ctx_flags, cpu, fmt_arg, ret));
2393 
2394         if (ret) goto error;
2395 
2396         /* link buffer format and context */
2397         ctx->ctx_buf_fmt = fmt;
2398         ctx->ctx_fl_is_sampling = 1; /* assume record() is defined */
2399 
2400         /*
2401          * check if buffer format wants to use perfmon buffer allocation/mapping service
2402          */
2403         ret = pfm_buf_fmt_getsize(fmt, task, ctx_flags, cpu, fmt_arg, &size);
2404         if (ret) goto error;
2405 
2406         if (size) {
2407                 /*
2408                  * buffer is always remapped into the caller's address space
2409                  */
2410                 ret = pfm_smpl_buffer_alloc(current, filp, ctx, size, &uaddr);
2411                 if (ret) goto error;
2412 
2413                 /* keep track of user address of buffer */
2414                 arg->ctx_smpl_vaddr = uaddr;
2415         }
2416         ret = pfm_buf_fmt_init(fmt, task, ctx->ctx_smpl_hdr, ctx_flags, cpu, fmt_arg);
2417 
2418 error:
2419         return ret;
2420 }
2421 
2422 static void
2423 pfm_reset_pmu_state(pfm_context_t *ctx)
2424 {
2425         int i;
2426 
2427         /*
2428          * install reset values for PMC.
2429          */
2430         for (i=1; PMC_IS_LAST(i) == 0; i++) {
2431                 if (PMC_IS_IMPL(i) == 0) continue;
2432                 ctx->ctx_pmcs[i] = PMC_DFL_VAL(i);
2433                 DPRINT(("pmc[%d]=0x%lx\n", i, ctx->ctx_pmcs[i]));
2434         }
2435         /*
2436          * PMD registers are set to 0UL when the context in memset()
2437          */
2438 
2439         /*
2440          * On context switched restore, we must restore ALL pmc and ALL pmd even
2441          * when they are not actively used by the task. In UP, the incoming process
2442          * may otherwise pick up left over PMC, PMD state from the previous process.
2443          * As opposed to PMD, stale PMC can cause harm to the incoming
2444          * process because they may change what is being measured.
2445          * Therefore, we must systematically reinstall the entire
2446          * PMC state. In SMP, the same thing is possible on the
2447          * same CPU but also on between 2 CPUs.
2448          *
2449          * The problem with PMD is information leaking especially
2450          * to user level when psr.sp=0
2451          *
2452          * There is unfortunately no easy way to avoid this problem
2453          * on either UP or SMP. This definitively slows down the
2454          * pfm_load_regs() function.
2455          */
2456 
2457          /*
2458           * bitmask of all PMCs accessible to this context
2459           *
2460           * PMC0 is treated differently.
2461           */
2462         ctx->ctx_all_pmcs[0] = pmu_conf->impl_pmcs[0] & ~0x1;
2463 
2464         /*
2465          * bitmask of all PMDs that are accessible to this context
2466          */
2467         ctx->ctx_all_pmds[0] = pmu_conf->impl_pmds[0];
2468 
2469         DPRINT(("<%d> all_pmcs=0x%lx all_pmds=0x%lx\n", ctx->ctx_fd, ctx->ctx_all_pmcs[0],ctx->ctx_all_pmds[0]));
2470 
2471         /*
2472          * useful in case of re-enable after disable
2473          */
2474         ctx->ctx_used_ibrs[0] = 0UL;
2475         ctx->ctx_used_dbrs[0] = 0UL;
2476 }
2477 
2478 static int
2479 pfm_ctx_getsize(void *arg, size_t *sz)
2480 {
2481         pfarg_context_t *req = (pfarg_context_t *)arg;
2482         pfm_buffer_fmt_t *fmt;
2483 
2484         *sz = 0;
2485 
2486         if (!pfm_uuid_cmp(req->ctx_smpl_buf_id, pfm_null_uuid)) return 0;
2487 
2488         fmt = pfm_find_buffer_fmt(req->ctx_smpl_buf_id);
2489         if (fmt == NULL) {
2490                 DPRINT(("cannot find buffer format\n"));
2491                 return -EINVAL;
2492         }
2493         /* get just enough to copy in user parameters */
2494         *sz = fmt->fmt_arg_size;
2495         DPRINT(("arg_size=%lu\n", *sz));
2496 
2497         return 0;
2498 }
2499 
2500 
2501 
2502 /*
2503  * cannot attach if :
2504  *      - kernel task
2505  *      - task not owned by caller
2506  *      - task incompatible with context mode
2507  */
2508 static int
2509 pfm_task_incompatible(pfm_context_t *ctx, struct task_struct *task)
2510 {
2511         /*
2512          * no kernel task or task not owner by caller
2513          */
2514         if (task->mm == NULL) {
2515                 DPRINT(("task [%d] has not memory context (kernel thread)\n", task_pid_nr(task)));
2516                 return -EPERM;
2517         }
2518         if (pfm_bad_permissions(task)) {
2519                 DPRINT(("no permission to attach to  [%d]\n", task_pid_nr(task)));
2520                 return -EPERM;
2521         }
2522         /*
2523          * cannot block in self-monitoring mode
2524          */
2525         if (CTX_OVFL_NOBLOCK(ctx) == 0 && task == current) {
2526                 DPRINT(("cannot load a blocking context on self for [%d]\n", task_pid_nr(task)));
2527                 return -EINVAL;
2528         }
2529 
2530         if (task->exit_state == EXIT_ZOMBIE) {
2531                 DPRINT(("cannot attach to  zombie task [%d]\n", task_pid_nr(task)));
2532                 return -EBUSY;
2533         }
2534 
2535         /*
2536          * always ok for self
2537          */
2538         if (task == current) return 0;
2539 
2540         if (!task_is_stopped_or_traced(task)) {
2541                 DPRINT(("cannot attach to non-stopped task [%d] state=%ld\n", task_pid_nr(task), task->state));
2542                 return -EBUSY;
2543         }
2544         /*
2545          * make sure the task is off any CPU
2546          */
2547         wait_task_inactive(task, 0);
2548 
2549         /* more to come... */
2550 
2551         return 0;
2552 }
2553 
2554 static int
2555 pfm_get_task(pfm_context_t *ctx, pid_t pid, struct task_struct **task)
2556 {
2557         struct task_struct *p = current;
2558         int ret;
2559 
2560         /* XXX: need to add more checks here */
2561         if (pid < 2) return -EPERM;
2562 
2563         if (pid != task_pid_vnr(current)) {
2564                 /* make sure task cannot go away while we operate on it */
2565                 p = find_get_task_by_vpid(pid);
2566                 if (!p)
2567                         return -ESRCH;
2568         }
2569 
2570         ret = pfm_task_incompatible(ctx, p);
2571         if (ret == 0) {
2572                 *task = p;
2573         } else if (p != current) {
2574                 pfm_put_task(p);
2575         }
2576         return ret;
2577 }
2578 
2579 
2580 
2581 static int
2582 pfm_context_create(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
2583 {
2584         pfarg_context_t *req = (pfarg_context_t *)arg;
2585         struct file *filp;
2586         struct path path;
2587         int ctx_flags;
2588         int fd;
2589         int ret;
2590 
2591         /* let's check the arguments first */
2592         ret = pfarg_is_sane(current, req);
2593         if (ret < 0)
2594                 return ret;
2595 
2596         ctx_flags = req->ctx_flags;
2597 
2598         ret = -ENOMEM;
2599 
2600         fd = get_unused_fd_flags(0);
2601         if (fd < 0)
2602                 return fd;
2603 
2604         ctx = pfm_context_alloc(ctx_flags);
2605         if (!ctx)
2606                 goto error;
2607 
2608         filp = pfm_alloc_file(ctx);
2609         if (IS_ERR(filp)) {
2610                 ret = PTR_ERR(filp);
2611                 goto error_file;
2612         }
2613 
2614         req->ctx_fd = ctx->ctx_fd = fd;
2615 
2616         /*
2617          * does the user want to sample?
2618          */
2619         if (pfm_uuid_cmp(req->ctx_smpl_buf_id, pfm_null_uuid)) {
2620                 ret = pfm_setup_buffer_fmt(current, filp, ctx, ctx_flags, 0, req);
2621                 if (ret)
2622                         goto buffer_error;
2623         }
2624 
2625         DPRINT(("ctx=%p flags=0x%x system=%d notify_block=%d excl_idle=%d no_msg=%d ctx_fd=%d\n",
2626                 ctx,
2627                 ctx_flags,
2628                 ctx->ctx_fl_system,
2629                 ctx->ctx_fl_block,
2630                 ctx->ctx_fl_excl_idle,
2631                 ctx->ctx_fl_no_msg,
2632                 ctx->ctx_fd));
2633 
2634         /*
2635          * initialize soft PMU state
2636          */
2637         pfm_reset_pmu_state(ctx);
2638 
2639         fd_install(fd, filp);
2640 
2641         return 0;
2642 
2643 buffer_error:
2644         path = filp->f_path;
2645         put_filp(filp);
2646         path_put(&path);
2647 
2648         if (ctx->ctx_buf_fmt) {
2649                 pfm_buf_fmt_exit(ctx->ctx_buf_fmt, current, NULL, regs);
2650         }
2651 error_file:
2652         pfm_context_free(ctx);
2653 
2654 error:
2655         put_unused_fd(fd);
2656         return ret;
2657 }
2658 
2659 static inline unsigned long
2660 pfm_new_counter_value (pfm_counter_t *reg, int is_long_reset)
2661 {
2662         unsigned long val = is_long_reset ? reg->long_reset : reg->short_reset;
2663         unsigned long new_seed, old_seed = reg->seed, mask = reg->mask;
2664         extern unsigned long carta_random32 (unsigned long seed);
2665 
2666         if (reg->flags & PFM_REGFL_RANDOM) {
2667                 new_seed = carta_random32(old_seed);
2668                 val -= (old_seed & mask);       /* counter values are negative numbers! */
2669                 if ((mask >> 32) != 0)
2670                         /* construct a full 64-bit random value: */
2671                         new_seed |= carta_random32(old_seed >> 32) << 32;
2672                 reg->seed = new_seed;
2673         }
2674         reg->lval = val;
2675         return val;
2676 }
2677 
2678 static void
2679 pfm_reset_regs_masked(pfm_context_t *ctx, unsigned long *ovfl_regs, int is_long_reset)
2680 {
2681         unsigned long mask = ovfl_regs[0];
2682         unsigned long reset_others = 0UL;
2683         unsigned long val;
2684         int i;
2685 
2686         /*
2687          * now restore reset value on sampling overflowed counters
2688          */
2689         mask >>= PMU_FIRST_COUNTER;
2690         for(i = PMU_FIRST_COUNTER; mask; i++, mask >>= 1) {
2691 
2692                 if ((mask & 0x1UL) == 0UL) continue;
2693 
2694                 ctx->ctx_pmds[i].val = val = pfm_new_counter_value(ctx->ctx_pmds+ i, is_long_reset);
2695                 reset_others        |= ctx->ctx_pmds[i].reset_pmds[0];
2696 
2697                 DPRINT_ovfl((" %s reset ctx_pmds[%d]=%lx\n", is_long_reset ? "long" : "short", i, val));
2698         }
2699 
2700         /*
2701          * Now take care of resetting the other registers
2702          */
2703         for(i = 0; reset_others; i++, reset_others >>= 1) {
2704 
2705                 if ((reset_others & 0x1) == 0) continue;
2706 
2707                 ctx->ctx_pmds[i].val = val = pfm_new_counter_value(ctx->ctx_pmds + i, is_long_reset);
2708 
2709                 DPRINT_ovfl(("%s reset_others pmd[%d]=%lx\n",
2710                           is_long_reset ? "long" : "short", i, val));
2711         }
2712 }
2713 
2714 static void
2715 pfm_reset_regs(pfm_context_t *ctx, unsigned long *ovfl_regs, int is_long_reset)
2716 {
2717         unsigned long mask = ovfl_regs[0];
2718         unsigned long reset_others = 0UL;
2719         unsigned long val;
2720         int i;
2721 
2722         DPRINT_ovfl(("ovfl_regs=0x%lx is_long_reset=%d\n", ovfl_regs[0], is_long_reset));
2723 
2724         if (ctx->ctx_state == PFM_CTX_MASKED) {
2725                 pfm_reset_regs_masked(ctx, ovfl_regs, is_long_reset);
2726                 return;
2727         }
2728 
2729         /*
2730          * now restore reset value on sampling overflowed counters
2731          */
2732         mask >>= PMU_FIRST_COUNTER;
2733         for(i = PMU_FIRST_COUNTER; mask; i++, mask >>= 1) {
2734 
2735                 if ((mask & 0x1UL) == 0UL) continue;
2736 
2737                 val           = pfm_new_counter_value(ctx->ctx_pmds+ i, is_long_reset);
2738                 reset_others |= ctx->ctx_pmds[i].reset_pmds[0];
2739 
2740                 DPRINT_ovfl((" %s reset ctx_pmds[%d]=%lx\n", is_long_reset ? "long" : "short", i, val));
2741 
2742                 pfm_write_soft_counter(ctx, i, val);
2743         }
2744 
2745         /*
2746          * Now take care of resetting the other registers
2747          */
2748         for(i = 0; reset_others; i++, reset_others >>= 1) {
2749 
2750                 if ((reset_others & 0x1) == 0) continue;
2751 
2752                 val = pfm_new_counter_value(ctx->ctx_pmds + i, is_long_reset);
2753 
2754                 if (PMD_IS_COUNTING(i)) {
2755                         pfm_write_soft_counter(ctx, i, val);
2756                 } else {
2757                         ia64_set_pmd(i, val);
2758                 }
2759                 DPRINT_ovfl(("%s reset_others pmd[%d]=%lx\n",
2760                           is_long_reset ? "long" : "short", i, val));
2761         }
2762         ia64_srlz_d();
2763 }
2764 
2765 static int
2766 pfm_write_pmcs(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
2767 {
2768         struct task_struct *task;
2769         pfarg_reg_t *req = (pfarg_reg_t *)arg;
2770         unsigned long value, pmc_pm;
2771         unsigned long smpl_pmds, reset_pmds, impl_pmds;
2772         unsigned int cnum, reg_flags, flags, pmc_type;
2773         int i, can_access_pmu = 0, is_loaded, is_system, expert_mode;
2774         int is_monitor, is_counting, state;
2775         int ret = -EINVAL;
2776         pfm_reg_check_t wr_func;
2777 #define PFM_CHECK_PMC_PM(x, y, z) ((x)->ctx_fl_system ^ PMC_PM(y, z))
2778 
2779         state     = ctx->ctx_state;
2780         is_loaded = state == PFM_CTX_LOADED ? 1 : 0;
2781         is_system = ctx->ctx_fl_system;
2782         task      = ctx->ctx_task;
2783         impl_pmds = pmu_conf->impl_pmds[0];
2784 
2785         if (state == PFM_CTX_ZOMBIE) return -EINVAL;
2786 
2787         if (is_loaded) {
2788                 /*
2789                  * In system wide and when the context is loaded, access can only happen
2790                  * when the caller is running on the CPU being monitored by the session.
2791                  * It does not have to be the owner (ctx_task) of the context per se.
2792                  */
2793                 if (is_system && ctx->ctx_cpu != smp_processor_id()) {
2794                         DPRINT(("should be running on CPU%d\n", ctx->ctx_cpu));
2795                         return -EBUSY;
2796                 }
2797                 can_access_pmu = GET_PMU_OWNER() == task || is_system ? 1 : 0;
2798         }
2799         expert_mode = pfm_sysctl.expert_mode; 
2800 
2801         for (i = 0; i < count; i++, req++) {
2802 
2803                 cnum       = req->reg_num;
2804                 reg_flags  = req->reg_flags;
2805                 value      = req->reg_value;
2806                 smpl_pmds  = req->reg_smpl_pmds[0];
2807                 reset_pmds = req->reg_reset_pmds[0];
2808                 flags      = 0;
2809 
2810 
2811                 if (cnum >= PMU_MAX_PMCS) {
2812                         DPRINT(("pmc%u is invalid\n", cnum));
2813                         goto error;
2814                 }
2815 
2816                 pmc_type   = pmu_conf->pmc_desc[cnum].type;
2817                 pmc_pm     = (value >> pmu_conf->pmc_desc[cnum].pm_pos) & 0x1;
2818                 is_counting = (pmc_type & PFM_REG_COUNTING) == PFM_REG_COUNTING ? 1 : 0;
2819                 is_monitor  = (pmc_type & PFM_REG_MONITOR) == PFM_REG_MONITOR ? 1 : 0;
2820 
2821                 /*
2822                  * we reject all non implemented PMC as well
2823                  * as attempts to modify PMC[0-3] which are used
2824                  * as status registers by the PMU
2825                  */
2826                 if ((pmc_type & PFM_REG_IMPL) == 0 || (pmc_type & PFM_REG_CONTROL) == PFM_REG_CONTROL) {
2827                         DPRINT(("pmc%u is unimplemented or no-access pmc_type=%x\n", cnum, pmc_type));
2828                         goto error;
2829                 }
2830                 wr_func = pmu_conf->pmc_desc[cnum].write_check;
2831                 /*
2832                  * If the PMC is a monitor, then if the value is not the default:
2833                  *      - system-wide session: PMCx.pm=1 (privileged monitor)
2834                  *      - per-task           : PMCx.pm=0 (user monitor)
2835                  */
2836                 if (is_monitor && value != PMC_DFL_VAL(cnum) && is_system ^ pmc_pm) {
2837                         DPRINT(("pmc%u pmc_pm=%lu is_system=%d\n",
2838                                 cnum,
2839                                 pmc_pm,
2840                                 is_system));
2841                         goto error;
2842                 }
2843 
2844                 if (is_counting) {
2845                         /*
2846                          * enforce generation of overflow interrupt. Necessary on all
2847                          * CPUs.
2848                          */
2849                         value |= 1 << PMU_PMC_OI;
2850 
2851                         if (reg_flags & PFM_REGFL_OVFL_NOTIFY) {
2852                                 flags |= PFM_REGFL_OVFL_NOTIFY;
2853                         }
2854 
2855                         if (reg_flags & PFM_REGFL_RANDOM) flags |= PFM_REGFL_RANDOM;
2856 
2857                         /* verify validity of smpl_pmds */
2858                         if ((smpl_pmds & impl_pmds) != smpl_pmds) {
2859                                 DPRINT(("invalid smpl_pmds 0x%lx for pmc%u\n", smpl_pmds, cnum));
2860                                 goto error;
2861                         }
2862 
2863                         /* verify validity of reset_pmds */
2864                         if ((reset_pmds & impl_pmds) != reset_pmds) {
2865                                 DPRINT(("invalid reset_pmds 0x%lx for pmc%u\n", reset_pmds, cnum));
2866                                 goto error;
2867                         }
2868                 } else {
2869                         if (reg_flags & (PFM_REGFL_OVFL_NOTIFY|PFM_REGFL_RANDOM)) {
2870                                 DPRINT(("cannot set ovfl_notify or random on pmc%u\n", cnum));
2871                                 goto error;
2872                         }
2873                         /* eventid on non-counting monitors are ignored */
2874                 }
2875 
2876                 /*
2877                  * execute write checker, if any
2878                  */
2879                 if (likely(expert_mode == 0 && wr_func)) {
2880                         ret = (*wr_func)(task, ctx, cnum, &value, regs);
2881                         if (ret) goto error;
2882                         ret = -EINVAL;
2883                 }
2884 
2885                 /*
2886                  * no error on this register
2887                  */
2888                 PFM_REG_RETFLAG_SET(req->reg_flags, 0);
2889 
2890                 /*
2891                  * Now we commit the changes to the software state
2892                  */
2893 
2894                 /*
2895                  * update overflow information
2896                  */
2897                 if (is_counting) {
2898                         /*
2899                          * full flag update each time a register is programmed
2900                          */
2901                         ctx->ctx_pmds[cnum].flags = flags;
2902 
2903                         ctx->ctx_pmds[cnum].reset_pmds[0] = reset_pmds;
2904                         ctx->ctx_pmds[cnum].smpl_pmds[0]  = smpl_pmds;
2905                         ctx->ctx_pmds[cnum].eventid       = req->reg_smpl_eventid;
2906 
2907                         /*
2908                          * Mark all PMDS to be accessed as used.
2909                          *
2910                          * We do not keep track of PMC because we have to
2911                          * systematically restore ALL of them.
2912                          *
2913                          * We do not update the used_monitors mask, because
2914                          * if we have not programmed them, then will be in
2915                          * a quiescent state, therefore we will not need to
2916                          * mask/restore then when context is MASKED.
2917                          */
2918                         CTX_USED_PMD(ctx, reset_pmds);
2919                         CTX_USED_PMD(ctx, smpl_pmds);
2920                         /*
2921                          * make sure we do not try to reset on
2922                          * restart because we have established new values
2923                          */
2924                         if (state == PFM_CTX_MASKED) ctx->ctx_ovfl_regs[0] &= ~1UL << cnum;
2925                 }
2926                 /*
2927                  * Needed in case the user does not initialize the equivalent
2928                  * PMD. Clearing is done indirectly via pfm_reset_pmu_state() so there is no
2929                  * possible leak here.
2930                  */
2931                 CTX_USED_PMD(ctx, pmu_conf->pmc_desc[cnum].dep_pmd[0]);
2932 
2933                 /*
2934                  * keep track of the monitor PMC that we are using.
2935                  * we save the value of the pmc in ctx_pmcs[] and if
2936                  * the monitoring is not stopped for the context we also
2937                  * place it in the saved state area so that it will be
2938                  * picked up later by the context switch code.
2939                  *
2940                  * The value in ctx_pmcs[] can only be changed in pfm_write_pmcs().
2941                  *
2942                  * The value in th_pmcs[] may be modified on overflow, i.e.,  when
2943                  * monitoring needs to be stopped.
2944                  */
2945                 if (is_monitor) CTX_USED_MONITOR(ctx, 1UL << cnum);
2946 
2947                 /*
2948                  * update context state
2949                  */
2950                 ctx->ctx_pmcs[cnum] = value;
2951 
2952                 if (is_loaded) {
2953                         /*
2954                          * write thread state
2955                          */
2956                         if (is_system == 0) ctx->th_pmcs[cnum] = value;
2957 
2958                         /*
2959                          * write hardware register if we can
2960                          */
2961                         if (can_access_pmu) {
2962                                 ia64_set_pmc(cnum, value);
2963                         }
2964 #ifdef CONFIG_SMP
2965                         else {
2966                                 /*
2967                                  * per-task SMP only here
2968                                  *
2969                                  * we are guaranteed that the task is not running on the other CPU,
2970                                  * we indicate that this PMD will need to be reloaded if the task
2971                                  * is rescheduled on the CPU it ran last on.
2972                                  */
2973                                 ctx->ctx_reload_pmcs[0] |= 1UL << cnum;
2974                         }
2975 #endif
2976                 }
2977 
2978                 DPRINT(("pmc[%u]=0x%lx ld=%d apmu=%d flags=0x%x all_pmcs=0x%lx used_pmds=0x%lx eventid=%ld smpl_pmds=0x%lx reset_pmds=0x%lx reloads_pmcs=0x%lx used_monitors=0x%lx ovfl_regs=0x%lx\n",
2979                           cnum,
2980                           value,
2981                           is_loaded,
2982                           can_access_pmu,
2983                           flags,
2984                           ctx->ctx_all_pmcs[0],
2985                           ctx->ctx_used_pmds[0],
2986                           ctx->ctx_pmds[cnum].eventid,
2987                           smpl_pmds,
2988                           reset_pmds,
2989                           ctx->ctx_reload_pmcs[0],
2990                           ctx->ctx_used_monitors[0],
2991                           ctx->ctx_ovfl_regs[0]));
2992         }
2993 
2994         /*
2995          * make sure the changes are visible
2996          */
2997         if (can_access_pmu) ia64_srlz_d();
2998 
2999         return 0;
3000 error:
3001         PFM_REG_RETFLAG_SET(req->reg_flags, PFM_REG_RETFL_EINVAL);
3002         return ret;
3003 }
3004 
3005 static int
3006 pfm_write_pmds(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
3007 {
3008         struct task_struct *task;
3009         pfarg_reg_t *req = (pfarg_reg_t *)arg;
3010         unsigned long value, hw_value, ovfl_mask;
3011         unsigned int cnum;
3012         int i, can_access_pmu = 0, state;
3013         int is_counting, is_loaded, is_system, expert_mode;
3014         int ret = -EINVAL;
3015         pfm_reg_check_t wr_func;
3016 
3017 
3018         state     = ctx->ctx_state;
3019         is_loaded = state == PFM_CTX_LOADED ? 1 : 0;
3020         is_system = ctx->ctx_fl_system;
3021         ovfl_mask = pmu_conf->ovfl_val;
3022         task      = ctx->ctx_task;
3023 
3024         if (unlikely(state == PFM_CTX_ZOMBIE)) return -EINVAL;
3025 
3026         /*
3027          * on both UP and SMP, we can only write to the PMC when the task is
3028          * the owner of the local PMU.
3029          */
3030         if (likely(is_loaded)) {
3031                 /*
3032                  * In system wide and when the context is loaded, access can only happen
3033                  * when the caller is running on the CPU being monitored by the session.
3034                  * It does not have to be the owner (ctx_task) of the context per se.
3035                  */
3036                 if (unlikely(is_system && ctx->ctx_cpu != smp_processor_id())) {
3037                         DPRINT(("should be running on CPU%d\n", ctx->ctx_cpu));
3038                         return -EBUSY;
3039                 }
3040                 can_access_pmu = GET_PMU_OWNER() == task || is_system ? 1 : 0;
3041         }
3042         expert_mode = pfm_sysctl.expert_mode; 
3043 
3044         for (i = 0; i < count; i++, req++) {
3045 
3046                 cnum  = req->reg_num;
3047                 value = req->reg_value;
3048 
3049                 if (!PMD_IS_IMPL(cnum)) {
3050                         DPRINT(("pmd[%u] is unimplemented or invalid\n", cnum));
3051                         goto abort_mission;
3052                 }
3053                 is_counting = PMD_IS_COUNTING(cnum);
3054                 wr_func     = pmu_conf->pmd_desc[cnum].write_check;
3055 
3056                 /*
3057                  * execute write checker, if any
3058                  */
3059                 if (unlikely(expert_mode == 0 && wr_func)) {
3060                         unsigned long v = value;
3061 
3062                         ret = (*wr_func)(task, ctx, cnum, &v, regs);
3063                         if (ret) goto abort_mission;
3064 
3065                         value = v;
3066                         ret   = -EINVAL;
3067                 }
3068 
3069                 /*
3070                  * no error on this register
3071                  */
3072                 PFM_REG_RETFLAG_SET(req->reg_flags, 0);
3073 
3074                 /*
3075                  * now commit changes to software state
3076                  */
3077                 hw_value = value;
3078 
3079                 /*
3080                  * update virtualized (64bits) counter
3081                  */
3082                 if (is_counting) {
3083                         /*
3084                          * write context state
3085                          */
3086                         ctx->ctx_pmds[cnum].lval = value;
3087 
3088                         /*
3089                          * when context is load we use the split value
3090                          */
3091                         if (is_loaded) {
3092                                 hw_value = value &  ovfl_mask;
3093                                 value    = value & ~ovfl_mask;
3094                         }
3095                 }
3096                 /*
3097                  * update reset values (not just for counters)
3098                  */
3099                 ctx->ctx_pmds[cnum].long_reset  = req->reg_long_reset;
3100                 ctx->ctx_pmds[cnum].short_reset = req->reg_short_reset;
3101 
3102                 /*
3103                  * update randomization parameters (not just for counters)
3104                  */
3105                 ctx->ctx_pmds[cnum].seed = req->reg_random_seed;
3106                 ctx->ctx_pmds[cnum].mask = req->reg_random_mask;
3107 
3108                 /*
3109                  * update context value
3110                  */
3111                 ctx->ctx_pmds[cnum].val  = value;
3112 
3113                 /*
3114                  * Keep track of what we use
3115                  *
3116                  * We do not keep track of PMC because we have to
3117                  * systematically restore ALL of them.
3118                  */
3119                 CTX_USED_PMD(ctx, PMD_PMD_DEP(cnum));
3120 
3121                 /*
3122                  * mark this PMD register used as well
3123                  */
3124                 CTX_USED_PMD(ctx, RDEP(cnum));
3125 
3126                 /*
3127                  * make sure we do not try to reset on
3128                  * restart because we have established new values
3129                  */
3130                 if (is_counting && state == PFM_CTX_MASKED) {
3131                         ctx->ctx_ovfl_regs[0] &= ~1UL << cnum;
3132                 }
3133 
3134                 if (is_loaded) {
3135                         /*
3136                          * write thread state
3137                          */
3138                         if (is_system == 0) ctx->th_pmds[cnum] = hw_value;
3139 
3140                         /*
3141                          * write hardware register if we can
3142                          */
3143                         if (can_access_pmu) {
3144                                 ia64_set_pmd(cnum, hw_value);
3145                         } else {
3146 #ifdef CONFIG_SMP
3147                                 /*
3148                                  * we are guaranteed that the task is not running on the other CPU,
3149                                  * we indicate that this PMD will need to be reloaded if the task
3150                                  * is rescheduled on the CPU it ran last on.
3151                                  */
3152                                 ctx->ctx_reload_pmds[0] |= 1UL << cnum;
3153 #endif
3154                         }
3155                 }
3156 
3157                 DPRINT(("pmd[%u]=0x%lx ld=%d apmu=%d, hw_value=0x%lx ctx_pmd=0x%lx  short_reset=0x%lx "
3158                           "long_reset=0x%lx notify=%c seed=0x%lx mask=0x%lx used_pmds=0x%lx reset_pmds=0x%lx reload_pmds=0x%lx all_pmds=0x%lx ovfl_regs=0x%lx\n",
3159                         cnum,
3160                         value,
3161                         is_loaded,
3162                         can_access_pmu,
3163                         hw_value,
3164                         ctx->ctx_pmds[cnum].val,
3165                         ctx->ctx_pmds[cnum].short_reset,
3166                         ctx->ctx_pmds[cnum].long_reset,
3167                         PMC_OVFL_NOTIFY(ctx, cnum) ? 'Y':'N',
3168                         ctx->ctx_pmds[cnum].seed,
3169                         ctx->ctx_pmds[cnum].mask,
3170                         ctx->ctx_used_pmds[0],
3171                         ctx->ctx_pmds[cnum].reset_pmds[0],
3172                         ctx->ctx_reload_pmds[0],
3173                         ctx->ctx_all_pmds[0],
3174                         ctx->ctx_ovfl_regs[0]));
3175         }
3176 
3177         /*
3178          * make changes visible
3179          */
3180         if (can_access_pmu) ia64_srlz_d();
3181 
3182         return 0;
3183 
3184 abort_mission:
3185         /*
3186          * for now, we have only one possibility for error
3187          */
3188         PFM_REG_RETFLAG_SET(req->reg_flags, PFM_REG_RETFL_EINVAL);
3189         return ret;
3190 }
3191 
3192 /*
3193  * By the way of PROTECT_CONTEXT(), interrupts are masked while we are in this function.
3194  * Therefore we know, we do not have to worry about the PMU overflow interrupt. If an
3195  * interrupt is delivered during the call, it will be kept pending until we leave, making
3196  * it appears as if it had been generated at the UNPROTECT_CONTEXT(). At least we are
3197  * guaranteed to return consistent data to the user, it may simply be old. It is not
3198  * trivial to treat the overflow while inside the call because you may end up in
3199  * some module sampling buffer code causing deadlocks.
3200  */
3201 static int
3202 pfm_read_pmds(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
3203 {
3204         struct task_struct *task;
3205         unsigned long val = 0UL, lval, ovfl_mask, sval;
3206         pfarg_reg_t *req = (pfarg_reg_t *)arg;
3207         unsigned int cnum, reg_flags = 0;
3208         int i, can_access_pmu = 0, state;
3209         int is_loaded, is_system, is_counting, expert_mode;
3210         int ret = -EINVAL;
3211         pfm_reg_check_t rd_func;
3212 
3213         /*
3214          * access is possible when loaded only for
3215          * self-monitoring tasks or in UP mode
3216          */
3217 
3218         state     = ctx->ctx_state;
3219         is_loaded = state == PFM_CTX_LOADED ? 1 : 0;
3220         is_system = ctx->ctx_fl_system;
3221         ovfl_mask = pmu_conf->ovfl_val;
3222         task      = ctx->ctx_task;
3223 
3224         if (state == PFM_CTX_ZOMBIE) return -EINVAL;
3225 
3226         if (likely(is_loaded)) {
3227                 /*
3228                  * In system wide and when the context is loaded, access can only happen
3229                  * when the caller is running on the CPU being monitored by the session.
3230                  * It does not have to be the owner (ctx_task) of the context per se.
3231                  */
3232                 if (unlikely(is_system && ctx->ctx_cpu != smp_processor_id())) {
3233                         DPRINT(("should be running on CPU%d\n", ctx->ctx_cpu));
3234                         return -EBUSY;
3235                 }
3236                 /*
3237                  * this can be true when not self-monitoring only in UP
3238                  */
3239                 can_access_pmu = GET_PMU_OWNER() == task || is_system ? 1 : 0;
3240 
3241                 if (can_access_pmu) ia64_srlz_d();
3242         }
3243         expert_mode = pfm_sysctl.expert_mode; 
3244 
3245         DPRINT(("ld=%d apmu=%d ctx_state=%d\n",
3246                 is_loaded,
3247                 can_access_pmu,
3248                 state));
3249 
3250         /*
3251          * on both UP and SMP, we can only read the PMD from the hardware register when
3252          * the task is the owner of the local PMU.
3253          */
3254 
3255         for (i = 0; i < count; i++, req++) {
3256 
3257                 cnum        = req->reg_num;
3258                 reg_flags   = req->reg_flags;
3259 
3260                 if (unlikely(!PMD_IS_IMPL(cnum))) goto error;
3261                 /*
3262                  * we can only read the register that we use. That includes
3263                  * the one we explicitly initialize AND the one we want included
3264                  * in the sampling buffer (smpl_regs).
3265                  *
3266                  * Having this restriction allows optimization in the ctxsw routine
3267                  * without compromising security (leaks)
3268                  */
3269                 if (unlikely(!CTX_IS_USED_PMD(ctx, cnum))) goto error;
3270 
3271                 sval        = ctx->ctx_pmds[cnum].val;
3272                 lval        = ctx->ctx_pmds[cnum].lval;
3273                 is_counting = PMD_IS_COUNTING(cnum);
3274 
3275                 /*
3276                  * If the task is not the current one, then we check if the
3277                  * PMU state is still in the local live register due to lazy ctxsw.
3278                  * If true, then we read directly from the registers.
3279                  */
3280                 if (can_access_pmu){
3281                         val = ia64_get_pmd(cnum);
3282                 } else {
3283                         /*
3284                          * context has been saved
3285                          * if context is zombie, then task does not exist anymore.
3286                          * In this case, we use the full value saved in the context (pfm_flush_regs()).
3287                          */
3288                         val = is_loaded ? ctx->th_pmds[cnum] : 0UL;
3289                 }
3290                 rd_func = pmu_conf->pmd_desc[cnum].read_check;
3291 
3292                 if (is_counting) {
3293                         /*
3294                          * XXX: need to check for overflow when loaded
3295                          */
3296                         val &= ovfl_mask;
3297                         val += sval;
3298                 }
3299 
3300                 /*
3301                  * execute read checker, if any
3302                  */
3303                 if (unlikely(expert_mode == 0 && rd_func)) {
3304                         unsigned long v = val;
3305                         ret = (*rd_func)(ctx->ctx_task, ctx, cnum, &v, regs);
3306                         if (ret) goto error;
3307                         val = v;
3308                         ret = -EINVAL;
3309                 }
3310 
3311                 PFM_REG_RETFLAG_SET(reg_flags, 0);
3312 
3313                 DPRINT(("pmd[%u]=0x%lx\n", cnum, val));
3314 
3315                 /*
3316                  * update register return value, abort all if problem during copy.
3317                  * we only modify the reg_flags field. no check mode is fine because
3318                  * access has been verified upfront in sys_perfmonctl().
3319                  */
3320                 req->reg_value            = val;
3321                 req->reg_flags            = reg_flags;
3322                 req->reg_last_reset_val   = lval;
3323         }
3324 
3325         return 0;
3326 
3327 error:
3328         PFM_REG_RETFLAG_SET(req->reg_flags, PFM_REG_RETFL_EINVAL);
3329         return ret;
3330 }
3331 
3332 int
3333 pfm_mod_write_pmcs(struct task_struct *task, void *req, unsigned int nreq, struct pt_regs *regs)
3334 {
3335         pfm_context_t *ctx;
3336 
3337         if (req == NULL) return -EINVAL;
3338 
3339         ctx = GET_PMU_CTX();
3340 
3341         if (ctx == NULL) return -EINVAL;
3342 
3343         /*
3344          * for now limit to current task, which is enough when calling
3345          * from overflow handler
3346          */
3347         if (task != current && ctx->ctx_fl_system == 0) return -EBUSY;
3348 
3349         return pfm_write_pmcs(ctx, req, nreq, regs);
3350 }
3351 EXPORT_SYMBOL(pfm_mod_write_pmcs);
3352 
3353 int
3354 pfm_mod_read_pmds(struct task_struct *task, void *req, unsigned int nreq, struct pt_regs *regs)
3355 {
3356         pfm_context_t *ctx;
3357 
3358         if (req == NULL) return -EINVAL;
3359 
3360         ctx = GET_PMU_CTX();
3361 
3362         if (ctx == NULL) return -EINVAL;
3363 
3364         /*
3365          * for now limit to current task, which is enough when calling
3366          * from overflow handler
3367          */
3368         if (task != current && ctx->ctx_fl_system == 0) return -EBUSY;
3369 
3370         return pfm_read_pmds(ctx, req, nreq, regs);
3371 }
3372 EXPORT_SYMBOL(pfm_mod_read_pmds);
3373 
3374 /*
3375  * Only call this function when a process it trying to
3376  * write the debug registers (reading is always allowed)
3377  */
3378 int
3379 pfm_use_debug_registers(struct task_struct *task)
3380 {
3381         pfm_context_t *ctx = task->thread.pfm_context;
3382         unsigned long flags;
3383         int ret = 0;
3384 
3385         if (pmu_conf->use_rr_dbregs == 0) return 0;
3386 
3387         DPRINT(("called for [%d]\n", task_pid_nr(task)));
3388 
3389         /*
3390          * do it only once
3391          */
3392         if (task->thread.flags & IA64_THREAD_DBG_VALID) return 0;
3393 
3394         /*
3395          * Even on SMP, we do not need to use an atomic here because
3396          * the only way in is via ptrace() and this is possible only when the
3397          * process is stopped. Even in the case where the ctxsw out is not totally
3398          * completed by the time we come here, there is no way the 'stopped' process
3399          * could be in the middle of fiddling with the pfm_write_ibr_dbr() routine.
3400          * So this is always safe.
3401          */
3402         if (ctx && ctx->ctx_fl_using_dbreg == 1) return -1;
3403 
3404         LOCK_PFS(flags);
3405 
3406         /*
3407          * We cannot allow setting breakpoints when system wide monitoring
3408          * sessions are using the debug registers.
3409          */
3410         if (pfm_sessions.pfs_sys_use_dbregs> 0)
3411                 ret = -1;
3412         else
3413                 pfm_sessions.pfs_ptrace_use_dbregs++;
3414 
3415         DPRINT(("ptrace_use_dbregs=%u  sys_use_dbregs=%u by [%d] ret = %d\n",
3416                   pfm_sessions.pfs_ptrace_use_dbregs,
3417                   pfm_sessions.pfs_sys_use_dbregs,
3418                   task_pid_nr(task), ret));
3419 
3420         UNLOCK_PFS(flags);
3421 
3422         return ret;
3423 }
3424 
3425 /*
3426  * This function is called for every task that exits with the
3427  * IA64_THREAD_DBG_VALID set. This indicates a task which was
3428  * able to use the debug registers for debugging purposes via
3429  * ptrace(). Therefore we know it was not using them for
3430  * performance monitoring, so we only decrement the number
3431  * of "ptraced" debug register users to keep the count up to date
3432  */
3433 int
3434 pfm_release_debug_registers(struct task_struct *task)
3435 {
3436         unsigned long flags;
3437         int ret;
3438 
3439         if (pmu_conf->use_rr_dbregs == 0) return 0;
3440 
3441         LOCK_PFS(flags);
3442         if (pfm_sessions.pfs_ptrace_use_dbregs == 0) {
3443                 printk(KERN_ERR "perfmon: invalid release for [%d] ptrace_use_dbregs=0\n", task_pid_nr(task));
3444                 ret = -1;
3445         }  else {
3446                 pfm_sessions.pfs_ptrace_use_dbregs--;
3447                 ret = 0;
3448         }
3449         UNLOCK_PFS(flags);
3450 
3451         return ret;
3452 }
3453 
3454 static int
3455 pfm_restart(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
3456 {
3457         struct task_struct *task;
3458         pfm_buffer_fmt_t *fmt;
3459         pfm_ovfl_ctrl_t rst_ctrl;
3460         int state, is_system;
3461         int ret = 0;
3462 
3463         state     = ctx->ctx_state;
3464         fmt       = ctx->ctx_buf_fmt;
3465         is_system = ctx->ctx_fl_system;
3466         task      = PFM_CTX_TASK(ctx);
3467 
3468         switch(state) {
3469                 case PFM_CTX_MASKED:
3470                         break;
3471                 case PFM_CTX_LOADED: 
3472                         if (CTX_HAS_SMPL(ctx) && fmt->fmt_restart_active) break;
3473                         /* fall through */
3474                 case PFM_CTX_UNLOADED:
3475                 case PFM_CTX_ZOMBIE:
3476                         DPRINT(("invalid state=%d\n", state));
3477                         return -EBUSY;
3478                 default:
3479                         DPRINT(("state=%d, cannot operate (no active_restart handler)\n", state));
3480                         return -EINVAL;
3481         }
3482 
3483         /*
3484          * In system wide and when the context is loaded, access can only happen
3485          * when the caller is running on the CPU being monitored by the session.
3486          * It does not have to be the owner (ctx_task) of the context per se.
3487          */
3488         if (is_system && ctx->ctx_cpu != smp_processor_id()) {
3489                 DPRINT(("should be running on CPU%d\n", ctx->ctx_cpu));
3490                 return -EBUSY;
3491         }
3492 
3493         /* sanity check */
3494         if (unlikely(task == NULL)) {
3495                 printk(KERN_ERR "perfmon: [%d] pfm_restart no task\n", task_pid_nr(current));
3496                 return -EINVAL;
3497         }
3498 
3499         if (task == current || is_system) {
3500 
3501                 fmt = ctx->ctx_buf_fmt;
3502 
3503                 DPRINT(("restarting self %d ovfl=0x%lx\n",
3504                         task_pid_nr(task),
3505                         ctx->ctx_ovfl_regs[0]));
3506 
3507                 if (CTX_HAS_SMPL(ctx)) {
3508 
3509                         prefetch(ctx->ctx_smpl_hdr);
3510 
3511                         rst_ctrl.bits.mask_monitoring = 0;
3512                         rst_ctrl.bits.reset_ovfl_pmds = 0;
3513 
3514                         if (state == PFM_CTX_LOADED)
3515                                 ret = pfm_buf_fmt_restart_active(fmt, task, &rst_ctrl, ctx->ctx_smpl_hdr, regs);
3516                         else
3517                                 ret = pfm_buf_fmt_restart(fmt, task, &rst_ctrl, ctx->ctx_smpl_hdr, regs);
3518                 } else {
3519                         rst_ctrl.bits.mask_monitoring = 0;
3520                         rst_ctrl.bits.reset_ovfl_pmds = 1;
3521                 }
3522 
3523                 if (ret == 0) {
3524                         if (rst_ctrl.bits.reset_ovfl_pmds)
3525                                 pfm_reset_regs(ctx, ctx->ctx_ovfl_regs, PFM_PMD_LONG_RESET);
3526 
3527                         if (rst_ctrl.bits.mask_monitoring == 0) {
3528                                 DPRINT(("resuming monitoring for [%d]\n", task_pid_nr(task)));
3529 
3530                                 if (state == PFM_CTX_MASKED) pfm_restore_monitoring(task);
3531                         } else {
3532                                 DPRINT(("keeping monitoring stopped for [%d]\n", task_pid_nr(task)));
3533 
3534                                 // cannot use pfm_stop_monitoring(task, regs);
3535                         }
3536                 }
3537                 /*
3538                  * clear overflowed PMD mask to remove any stale information
3539                  */
3540                 ctx->ctx_ovfl_regs[0] = 0UL;
3541 
3542                 /*
3543                  * back to LOADED state
3544                  */
3545                 ctx->ctx_state = PFM_CTX_LOADED;
3546 
3547                 /*
3548                  * XXX: not really useful for self monitoring
3549                  */
3550                 ctx->ctx_fl_can_restart = 0;
3551 
3552                 return 0;
3553         }
3554 
3555         /* 
3556          * restart another task
3557          */
3558 
3559         /*
3560          * When PFM_CTX_MASKED, we cannot issue a restart before the previous 
3561          * one is seen by the task.
3562          */
3563         if (state == PFM_CTX_MASKED) {
3564                 if (ctx->ctx_fl_can_restart == 0) return -EINVAL;
3565                 /*
3566                  * will prevent subsequent restart before this one is
3567                  * seen by other task
3568                  */
3569                 ctx->ctx_fl_can_restart = 0;
3570         }
3571 
3572         /*
3573          * if blocking, then post the semaphore is PFM_CTX_MASKED, i.e.
3574          * the task is blocked or on its way to block. That's the normal
3575          * restart path. If the monitoring is not masked, then the task
3576          * can be actively monitoring and we cannot directly intervene.
3577          * Therefore we use the trap mechanism to catch the task and
3578          * force it to reset the buffer/reset PMDs.
3579          *
3580          * if non-blocking, then we ensure that the task will go into
3581          * pfm_handle_work() before returning to user mode.
3582          *
3583          * We cannot explicitly reset another task, it MUST always
3584          * be done by the task itself. This works for system wide because
3585          * the tool that is controlling the session is logically doing 
3586          * "self-monitoring".
3587          */
3588         if (CTX_OVFL_NOBLOCK(ctx) == 0 && state == PFM_CTX_MASKED) {
3589                 DPRINT(("unblocking [%d]\n", task_pid_nr(task)));
3590                 complete(&ctx->ctx_restart_done);
3591         } else {
3592                 DPRINT(("[%d] armed exit trap\n", task_pid_nr(task)));
3593 
3594                 ctx->ctx_fl_trap_reason = PFM_TRAP_REASON_RESET;
3595 
3596                 PFM_SET_WORK_PENDING(task, 1);
3597 
3598                 set_notify_resume(task);
3599 
3600                 /*
3601                  * XXX: send reschedule if task runs on another CPU
3602                  */
3603         }
3604         return 0;
3605 }
3606 
3607 static int
3608 pfm_debug(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
3609 {
3610         unsigned int m = *(unsigned int *)arg;
3611 
3612         pfm_sysctl.debug = m == 0 ? 0 : 1;
3613 
3614         printk(KERN_INFO "perfmon debugging %s (timing reset)\n", pfm_sysctl.debug ? "on" : "off");
3615 
3616         if (m == 0) {
3617                 memset(pfm_stats, 0, sizeof(pfm_stats));
3618                 for(m=0; m < NR_CPUS; m++) pfm_stats[m].pfm_ovfl_intr_cycles_min = ~0UL;
3619         }
3620         return 0;
3621 }
3622 
3623 /*
3624  * arg can be NULL and count can be zero for this function
3625  */
3626 static int
3627 pfm_write_ibr_dbr(int mode, pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
3628 {
3629         struct thread_struct *thread = NULL;
3630         struct task_struct *task;
3631         pfarg_dbreg_t *req = (pfarg_dbreg_t *)arg;
3632         unsigned long flags;
3633         dbreg_t dbreg;
3634         unsigned int rnum;
3635         int first_time;
3636         int ret = 0, state;
3637         int i, can_access_pmu = 0;
3638         int is_system, is_loaded;
3639 
3640         if (pmu_conf->use_rr_dbregs == 0) return -EINVAL;
3641 
3642         state     = ctx->ctx_state;
3643         is_loaded = state == PFM_CTX_LOADED ? 1 : 0;
3644         is_system = ctx->ctx_fl_system;
3645         task      = ctx->ctx_task;
3646 
3647         if (state == PFM_CTX_ZOMBIE) return -EINVAL;
3648 
3649         /*
3650          * on both UP and SMP, we can only write to the PMC when the task is
3651          * the owner of the local PMU.
3652          */
3653         if (is_loaded) {
3654                 thread = &task->thread;
3655                 /*
3656                  * In system wide and when the context is loaded, access can only happen
3657                  * when the caller is running on the CPU being monitored by the session.
3658                  * It does not have to be the owner (ctx_task) of the context per se.
3659                  */
3660                 if (unlikely(is_system && ctx->ctx_cpu != smp_processor_id())) {
3661                         DPRINT(("should be running on CPU%d\n", ctx->ctx_cpu));
3662                         return -EBUSY;
3663                 }
3664                 can_access_pmu = GET_PMU_OWNER() == task || is_system ? 1 : 0;
3665         }
3666 
3667         /*
3668          * we do not need to check for ipsr.db because we do clear ibr.x, dbr.r, and dbr.w
3669          * ensuring that no real breakpoint can be installed via this call.
3670          *
3671          * IMPORTANT: regs can be NULL in this function
3672          */
3673 
3674         first_time = ctx->ctx_fl_using_dbreg == 0;
3675 
3676         /*
3677          * don't bother if we are loaded and task is being debugged
3678          */
3679         if (is_loaded && (thread->flags & IA64_THREAD_DBG_VALID) != 0) {
3680                 DPRINT(("debug registers already in use for [%d]\n", task_pid_nr(task)));
3681                 return -EBUSY;
3682         }
3683 
3684         /*
3685          * check for debug registers in system wide mode
3686          *
3687          * If though a check is done in pfm_context_load(),
3688          * we must repeat it here, in case the registers are
3689          * written after the context is loaded
3690          */
3691         if (is_loaded) {
3692                 LOCK_PFS(flags);
3693 
3694                 if (first_time && is_system) {
3695                         if (pfm_sessions.pfs_ptrace_use_dbregs)
3696                                 ret = -EBUSY;
3697                         else
3698                                 pfm_sessions.pfs_sys_use_dbregs++;
3699                 }
3700                 UNLOCK_PFS(flags);
3701         }
3702 
3703         if (ret != 0) return ret;
3704 
3705         /*
3706          * mark ourself as user of the debug registers for
3707          * perfmon purposes.
3708          */
3709         ctx->ctx_fl_using_dbreg = 1;
3710 
3711         /*
3712          * clear hardware registers to make sure we don't
3713          * pick up stale state.
3714          *
3715          * for a system wide session, we do not use
3716          * thread.dbr, thread.ibr because this process
3717          * never leaves the current CPU and the state
3718          * is shared by all processes running on it
3719          */
3720         if (first_time && can_access_pmu) {
3721                 DPRINT(("[%d] clearing ibrs, dbrs\n", task_pid_nr(task)));
3722                 for (i=0; i < pmu_conf->num_ibrs; i++) {
3723                         ia64_set_ibr(i, 0UL);
3724                         ia64_dv_serialize_instruction();
3725                 }
3726                 ia64_srlz_i();
3727                 for (i=0; i < pmu_conf->num_dbrs; i++) {
3728                         ia64_set_dbr(i, 0UL);
3729                         ia64_dv_serialize_data();
3730                 }
3731                 ia64_srlz_d();
3732         }
3733 
3734         /*
3735          * Now install the values into the registers
3736          */
3737         for (i = 0; i < count; i++, req++) {
3738 
3739                 rnum      = req->dbreg_num;
3740                 dbreg.val = req->dbreg_value;
3741 
3742                 ret = -EINVAL;
3743 
3744                 if ((mode == PFM_CODE_RR && rnum >= PFM_NUM_IBRS) || ((mode == PFM_DATA_RR) && rnum >= PFM_NUM_DBRS)) {
3745                         DPRINT(("invalid register %u val=0x%lx mode=%d i=%d count=%d\n",
3746                                   rnum, dbreg.val, mode, i, count));
3747 
3748                         goto abort_mission;
3749                 }
3750 
3751                 /*
3752                  * make sure we do not install enabled breakpoint
3753                  */
3754                 if (rnum & 0x1) {
3755                         if (mode == PFM_CODE_RR)
3756                                 dbreg.ibr.ibr_x = 0;
3757                         else
3758                                 dbreg.dbr.dbr_r = dbreg.dbr.dbr_w = 0;
3759                 }
3760 
3761                 PFM_REG_RETFLAG_SET(req->dbreg_flags, 0);
3762 
3763                 /*
3764                  * Debug registers, just like PMC, can only be modified
3765                  * by a kernel call. Moreover, perfmon() access to those
3766                  * registers are centralized in this routine. The hardware
3767                  * does not modify the value of these registers, therefore,
3768                  * if we save them as they are written, we can avoid having
3769                  * to save them on context switch out. This is made possible
3770                  * by the fact that when perfmon uses debug registers, ptrace()
3771                  * won't be able to modify them concurrently.
3772                  */
3773                 if (mode == PFM_CODE_RR) {
3774                         CTX_USED_IBR(ctx, rnum);
3775 
3776                         if (can_access_pmu) {
3777                                 ia64_set_ibr(rnum, dbreg.val);
3778                                 ia64_dv_serialize_instruction();
3779                         }
3780 
3781                         ctx->ctx_ibrs[rnum] = dbreg.val;
3782 
3783                         DPRINT(("write ibr%u=0x%lx used_ibrs=0x%x ld=%d apmu=%d\n",
3784                                 rnum, dbreg.val, ctx->ctx_used_ibrs[0], is_loaded, can_access_pmu));
3785                 } else {
3786                         CTX_USED_DBR(ctx, rnum);
3787 
3788                         if (can_access_pmu) {
3789                                 ia64_set_dbr(rnum, dbreg.val);
3790                                 ia64_dv_serialize_data();
3791                         }
3792                         ctx->ctx_dbrs[rnum] = dbreg.val;
3793 
3794                         DPRINT(("write dbr%u=0x%lx used_dbrs=0x%x ld=%d apmu=%d\n",
3795                                 rnum, dbreg.val, ctx->ctx_used_dbrs[0], is_loaded, can_access_pmu));
3796                 }
3797         }
3798 
3799         return 0;
3800 
3801 abort_mission:
3802         /*
3803          * in case it was our first attempt, we undo the global modifications
3804          */
3805         if (first_time) {
3806                 LOCK_PFS(flags);
3807                 if (ctx->ctx_fl_system) {
3808                         pfm_sessions.pfs_sys_use_dbregs--;
3809                 }
3810                 UNLOCK_PFS(flags);
3811                 ctx->ctx_fl_using_dbreg = 0;
3812         }
3813         /*
3814          * install error return flag
3815          */
3816         PFM_REG_RETFLAG_SET(req->dbreg_flags, PFM_REG_RETFL_EINVAL);
3817 
3818         return ret;
3819 }
3820 
3821 static int
3822 pfm_write_ibrs(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
3823 {
3824         return pfm_write_ibr_dbr(PFM_CODE_RR, ctx, arg, count, regs);
3825 }
3826 
3827 static int
3828 pfm_write_dbrs(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
3829 {
3830         return pfm_write_ibr_dbr(PFM_DATA_RR, ctx, arg, count, regs);
3831 }
3832 
3833 int
3834 pfm_mod_write_ibrs(struct task_struct *task, void *req, unsigned int nreq, struct pt_regs *regs)
3835 {
3836         pfm_context_t *ctx;
3837 
3838         if (req == NULL) return -EINVAL;
3839 
3840         ctx = GET_PMU_CTX();
3841 
3842         if (ctx == NULL) return -EINVAL;
3843 
3844         /*
3845          * for now limit to current task, which is enough when calling
3846          * from overflow handler
3847          */
3848         if (task != current && ctx->ctx_fl_system == 0) return -EBUSY;
3849 
3850         return pfm_write_ibrs(ctx, req, nreq, regs);
3851 }
3852 EXPORT_SYMBOL(pfm_mod_write_ibrs);
3853 
3854 int
3855 pfm_mod_write_dbrs(struct task_struct *task, void *req, unsigned int nreq, struct pt_regs *regs)
3856 {
3857         pfm_context_t *ctx;
3858 
3859         if (req == NULL) return -EINVAL;
3860 
3861         ctx = GET_PMU_CTX();
3862 
3863         if (ctx == NULL) return -EINVAL;
3864 
3865         /*
3866          * for now limit to current task, which is enough when calling
3867          * from overflow handler
3868          */
3869         if (task != current && ctx->ctx_fl_system == 0) return -EBUSY;
3870 
3871         return pfm_write_dbrs(ctx, req, nreq, regs);
3872 }
3873 EXPORT_SYMBOL(pfm_mod_write_dbrs);
3874 
3875 
3876 static int
3877 pfm_get_features(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
3878 {
3879         pfarg_features_t *req = (pfarg_features_t *)arg;
3880 
3881         req->ft_version = PFM_VERSION;
3882         return 0;
3883 }
3884 
3885 static int
3886 pfm_stop(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
3887 {
3888         struct pt_regs *tregs;
3889         struct task_struct *task = PFM_CTX_TASK(ctx);
3890         int state, is_system;
3891 
3892         state     = ctx->ctx_state;
3893         is_system = ctx->ctx_fl_system;
3894 
3895         /*
3896          * context must be attached to issue the stop command (includes LOADED,MASKED,ZOMBIE)
3897          */
3898         if (state == PFM_CTX_UNLOADED) return -EINVAL;
3899 
3900         /*
3901          * In system wide and when the context is loaded, access can only happen
3902          * when the caller is running on the CPU being monitored by the session.
3903          * It does not have to be the owner (ctx_task) of the context per se.
3904          */
3905         if (is_system && ctx->ctx_cpu != smp_processor_id()) {
3906                 DPRINT(("should be running on CPU%d\n", ctx->ctx_cpu));
3907                 return -EBUSY;
3908         }
3909         DPRINT(("task [%d] ctx_state=%d is_system=%d\n",
3910                 task_pid_nr(PFM_CTX_TASK(ctx)),
3911                 state,
3912                 is_system));
3913         /*
3914          * in system mode, we need to update the PMU directly
3915          * and the user level state of the caller, which may not
3916          * necessarily be the creator of the context.
3917          */
3918         if (is_system) {
3919                 /*
3920                  * Update local PMU first
3921                  *
3922                  * disable dcr pp
3923                  */
3924                 ia64_setreg(_IA64_REG_CR_DCR, ia64_getreg(_IA64_REG_CR_DCR) & ~IA64_DCR_PP);
3925                 ia64_srlz_i();
3926 
3927                 /*
3928                  * update local cpuinfo
3929                  */
3930                 PFM_CPUINFO_CLEAR(PFM_CPUINFO_DCR_PP);
3931 
3932                 /*
3933                  * stop monitoring, does srlz.i
3934                  */
3935                 pfm_clear_psr_pp();
3936 
3937                 /*
3938                  * stop monitoring in the caller
3939                  */
3940                 ia64_psr(regs)->pp = 0;
3941 
3942                 return 0;
3943         }
3944         /*
3945          * per-task mode
3946          */
3947 
3948         if (task == current) {
3949                 /* stop monitoring  at kernel level */
3950                 pfm_clear_psr_up();
3951 
3952                 /*
3953                  * stop monitoring at the user level
3954                  */
3955                 ia64_psr(regs)->up = 0;
3956         } else {
3957                 tregs = task_pt_regs(task);
3958 
3959                 /*
3960                  * stop monitoring at the user level
3961                  */
3962                 ia64_psr(tregs)->up = 0;
3963 
3964                 /*
3965                  * monitoring disabled in kernel at next reschedule
3966                  */
3967                 ctx->ctx_saved_psr_up = 0;
3968                 DPRINT(("task=[%d]\n", task_pid_nr(task)));
3969         }
3970         return 0;
3971 }
3972 
3973 
3974 static int
3975 pfm_start(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
3976 {
3977         struct pt_regs *tregs;
3978         int state, is_system;
3979 
3980         state     = ctx->ctx_state;
3981         is_system = ctx->ctx_fl_system;
3982 
3983         if (state != PFM_CTX_LOADED) return -EINVAL;
3984 
3985         /*
3986          * In system wide and when the context is loaded, access can only happen
3987          * when the caller is running on the CPU being monitored by the session.
3988          * It does not have to be the owner (ctx_task) of the context per se.
3989          */
3990         if (is_system && ctx->ctx_cpu != smp_processor_id()) {
3991                 DPRINT(("should be running on CPU%d\n", ctx->ctx_cpu));
3992                 return -EBUSY;
3993         }
3994 
3995         /*
3996          * in system mode, we need to update the PMU directly
3997          * and the user level state of the caller, which may not
3998          * necessarily be the creator of the context.
3999          */
4000         if (is_system) {
4001 
4002                 /*
4003                  * set user level psr.pp for the caller
4004                  */
4005                 ia64_psr(regs)->pp = 1;
4006 
4007                 /*
4008                  * now update the local PMU and cpuinfo
4009                  */
4010                 PFM_CPUINFO_SET(PFM_CPUINFO_DCR_PP);
4011 
4012                 /*
4013                  * start monitoring at kernel level
4014                  */
4015                 pfm_set_psr_pp();
4016 
4017                 /* enable dcr pp */
4018                 ia64_setreg(_IA64_REG_CR_DCR, ia64_getreg(_IA64_REG_CR_DCR) | IA64_DCR_PP);
4019                 ia64_srlz_i();
4020 
4021                 return 0;
4022         }
4023 
4024         /*
4025          * per-process mode
4026          */
4027 
4028         if (ctx->ctx_task == current) {
4029 
4030                 /* start monitoring at kernel level */
4031                 pfm_set_psr_up();
4032 
4033                 /*
4034                  * activate monitoring at user level
4035                  */
4036                 ia64_psr(regs)->up = 1;
4037 
4038         } else {
4039                 tregs = task_pt_regs(ctx->ctx_task);
4040 
4041                 /*
4042                  * start monitoring at the kernel level the next
4043                  * time the task is scheduled
4044                  */
4045                 ctx->ctx_saved_psr_up = IA64_PSR_UP;
4046 
4047                 /*
4048                  * activate monitoring at user level
4049                  */
4050                 ia64_psr(tregs)->up = 1;
4051         }
4052         return 0;
4053 }
4054 
4055 static int
4056 pfm_get_pmc_reset(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
4057 {
4058         pfarg_reg_t *req = (pfarg_reg_t *)arg;
4059         unsigned int cnum;
4060         int i;
4061         int ret = -EINVAL;
4062 
4063         for (i = 0; i < count; i++, req++) {
4064 
4065                 cnum = req->reg_num;
4066 
4067                 if (!PMC_IS_IMPL(cnum)) goto abort_mission;
4068 
4069                 req->reg_value = PMC_DFL_VAL(cnum);
4070 
4071                 PFM_REG_RETFLAG_SET(req->reg_flags, 0);
4072 
4073                 DPRINT(("pmc_reset_val pmc[%u]=0x%lx\n", cnum, req->reg_value));
4074         }
4075         return 0;
4076 
4077 abort_mission:
4078         PFM_REG_RETFLAG_SET(req->reg_flags, PFM_REG_RETFL_EINVAL);
4079         return ret;
4080 }
4081 
4082 static int
4083 pfm_check_task_exist(pfm_context_t *ctx)
4084 {
4085         struct task_struct *g, *t;
4086         int ret = -ESRCH;
4087 
4088         read_lock(&tasklist_lock);
4089 
4090         do_each_thread (g, t) {
4091                 if (t->thread.pfm_context == ctx) {
4092                         ret = 0;
4093                         goto out;
4094                 }
4095         } while_each_thread (g, t);
4096 out:
4097         read_unlock(&tasklist_lock);
4098 
4099         DPRINT(("pfm_check_task_exist: ret=%d ctx=%p\n", ret, ctx));
4100 
4101         return ret;
4102 }
4103 
4104 static int
4105 pfm_context_load(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
4106 {
4107         struct task_struct *task;
4108         struct thread_struct *thread;
4109         struct pfm_context_t *old;
4110         unsigned long flags;
4111 #ifndef CONFIG_SMP
4112         struct task_struct *owner_task = NULL;
4113 #endif
4114         pfarg_load_t *req = (pfarg_load_t *)arg;
4115         unsigned long *pmcs_source, *pmds_source;
4116         int the_cpu;
4117         int ret = 0;
4118         int state, is_system, set_dbregs = 0;
4119 
4120         state     = ctx->ctx_state;
4121         is_system = ctx->ctx_fl_system;
4122         /*
4123          * can only load from unloaded or terminated state
4124          */
4125         if (state != PFM_CTX_UNLOADED) {
4126                 DPRINT(("cannot load to [%d], invalid ctx_state=%d\n",
4127                         req->load_pid,
4128                         ctx->ctx_state));
4129                 return -EBUSY;
4130         }
4131 
4132         DPRINT(("load_pid [%d] using_dbreg=%d\n", req->load_pid, ctx->ctx_fl_using_dbreg));
4133 
4134         if (CTX_OVFL_NOBLOCK(ctx) == 0 && req->load_pid == current->pid) {
4135                 DPRINT(("cannot use blocking mode on self\n"));
4136                 return -EINVAL;
4137         }
4138 
4139         ret = pfm_get_task(ctx, req->load_pid, &task);
4140         if (ret) {
4141                 DPRINT(("load_pid [%d] get_task=%d\n", req->load_pid, ret));
4142                 return ret;
4143         }
4144 
4145         ret = -EINVAL;
4146 
4147         /*
4148          * system wide is self monitoring only
4149          */
4150         if (is_system && task != current) {
4151                 DPRINT(("system wide is self monitoring only load_pid=%d\n",
4152                         req->load_pid));
4153                 goto error;
4154         }
4155 
4156         thread = &task->thread;
4157 
4158         ret = 0;
4159         /*
4160          * cannot load a context which is using range restrictions,
4161          * into a task that is being debugged.
4162          */
4163         if (ctx->ctx_fl_using_dbreg) {
4164                 if (thread->flags & IA64_THREAD_DBG_VALID) {
4165                         ret = -EBUSY;
4166                         DPRINT(("load_pid [%d] task is debugged, cannot load range restrictions\n", req->load_pid));
4167                         goto error;
4168                 }
4169                 LOCK_PFS(flags);
4170 
4171                 if (is_system) {
4172                         if (pfm_sessions.pfs_ptrace_use_dbregs) {
4173                                 DPRINT(("cannot load [%d] dbregs in use\n",
4174                                                         task_pid_nr(task)));
4175                                 ret = -EBUSY;
4176                         } else {
4177                                 pfm_sessions.pfs_sys_use_dbregs++;
4178                                 DPRINT(("load [%d] increased sys_use_dbreg=%u\n", task_pid_nr(task), pfm_sessions.pfs_sys_use_dbregs));
4179                                 set_dbregs = 1;
4180                         }
4181                 }
4182 
4183                 UNLOCK_PFS(flags);
4184 
4185                 if (ret) goto error;
4186         }
4187 
4188         /*
4189          * SMP system-wide monitoring implies self-monitoring.
4190          *
4191          * The programming model expects the task to
4192          * be pinned on a CPU throughout the session.
4193          * Here we take note of the current CPU at the
4194          * time the context is loaded. No call from
4195          * another CPU will be allowed.
4196          *
4197          * The pinning via shed_setaffinity()
4198          * must be done by the calling task prior
4199          * to this call.
4200          *
4201          * systemwide: keep track of CPU this session is supposed to run on
4202          */
4203         the_cpu = ctx->ctx_cpu = smp_processor_id();
4204 
4205         ret = -EBUSY;
4206         /*
4207          * now reserve the session
4208          */
4209         ret = pfm_reserve_session(current, is_system, the_cpu);
4210         if (ret) goto error;
4211 
4212         /*
4213          * task is necessarily stopped at this point.
4214          *
4215          * If the previous context was zombie, then it got removed in
4216          * pfm_save_regs(). Therefore we should not see it here.
4217          * If we see a context, then this is an active context
4218          *
4219          * XXX: needs to be atomic
4220          */
4221         DPRINT(("before cmpxchg() old_ctx=%p new_ctx=%p\n",
4222                 thread->pfm_context, ctx));
4223 
4224         ret = -EBUSY;
4225         old = ia64_cmpxchg(acq, &thread->pfm_context, NULL, ctx, sizeof(pfm_context_t *));
4226         if (old != NULL) {
4227                 DPRINT(("load_pid [%d] already has a context\n", req->load_pid));
4228                 goto error_unres;
4229         }
4230 
4231         pfm_reset_msgq(ctx);
4232 
4233         ctx->ctx_state = PFM_CTX_LOADED;
4234 
4235         /*
4236          * link context to task
4237          */
4238         ctx->ctx_task = task;
4239 
4240         if (is_system) {
4241                 /*
4242                  * we load as stopped
4243                  */
4244                 PFM_CPUINFO_SET(PFM_CPUINFO_SYST_WIDE);
4245                 PFM_CPUINFO_CLEAR(PFM_CPUINFO_DCR_PP);
4246 
4247                 if (ctx->ctx_fl_excl_idle) PFM_CPUINFO_SET(PFM_CPUINFO_EXCL_IDLE);
4248         } else {
4249                 thread->flags |= IA64_THREAD_PM_VALID;
4250         }
4251 
4252         /*
4253          * propagate into thread-state
4254          */
4255         pfm_copy_pmds(task, ctx);
4256         pfm_copy_pmcs(task, ctx);
4257 
4258         pmcs_source = ctx->th_pmcs;
4259         pmds_source = ctx->th_pmds;
4260 
4261         /*
4262          * always the case for system-wide
4263          */
4264         if (task == current) {
4265 
4266                 if (is_system == 0) {
4267 
4268                         /* allow user level control */
4269                         ia64_psr(regs)->sp = 0;
4270                         DPRINT(("clearing psr.sp for [%d]\n", task_pid_nr(task)));
4271 
4272                         SET_LAST_CPU(ctx, smp_processor_id());
4273                         INC_ACTIVATION();
4274                         SET_ACTIVATION(ctx);
4275 #ifndef CONFIG_SMP
4276                         /*
4277                          * push the other task out, if any
4278                          */
4279                         owner_task = GET_PMU_OWNER();
4280                         if (owner_task) pfm_lazy_save_regs(owner_task);
4281 #endif
4282                 }
4283                 /*
4284                  * load all PMD from ctx to PMU (as opposed to thread state)
4285                  * restore all PMC from ctx to PMU
4286                  */
4287                 pfm_restore_pmds(pmds_source, ctx->ctx_all_pmds[0]);
4288                 pfm_restore_pmcs(pmcs_source, ctx->ctx_all_pmcs[0]);
4289 
4290                 ctx->ctx_reload_pmcs[0] = 0UL;
4291                 ctx->ctx_reload_pmds[0] = 0UL;
4292 
4293                 /*
4294                  * guaranteed safe by earlier check against DBG_VALID
4295                  */
4296                 if (ctx->ctx_fl_using_dbreg) {
4297                         pfm_restore_ibrs(ctx->ctx_ibrs, pmu_conf->num_ibrs);
4298                         pfm_restore_dbrs(ctx->ctx_dbrs, pmu_conf->num_dbrs);
4299                 }
4300                 /*
4301                  * set new ownership
4302                  */
4303                 SET_PMU_OWNER(task, ctx);
4304 
4305                 DPRINT(("context loaded on PMU for [%d]\n", task_pid_nr(task)));
4306         } else {
4307                 /*
4308                  * when not current, task MUST be stopped, so this is safe
4309                  */
4310                 regs = task_pt_regs(task);
4311 
4312                 /* force a full reload */
4313                 ctx->ctx_last_activation = PFM_INVALID_ACTIVATION;
4314                 SET_LAST_CPU(ctx, -1);
4315 
4316                 /* initial saved psr (stopped) */
4317                 ctx->ctx_saved_psr_up = 0UL;
4318                 ia64_psr(regs)->up = ia64_psr(regs)->pp = 0;
4319         }
4320 
4321         ret = 0;
4322 
4323 error_unres:
4324         if (ret) pfm_unreserve_session(ctx, ctx->ctx_fl_system, the_cpu);
4325 error:
4326         /*
4327          * we must undo the dbregs setting (for system-wide)
4328          */
4329         if (ret && set_dbregs) {
4330                 LOCK_PFS(flags);
4331                 pfm_sessions.pfs_sys_use_dbregs--;
4332                 UNLOCK_PFS(flags);
4333         }
4334         /*
4335          * release task, there is now a link with the context
4336          */
4337         if (is_system == 0 && task != current) {
4338                 pfm_put_task(task);
4339 
4340                 if (ret == 0) {
4341                         ret = pfm_check_task_exist(ctx);
4342                         if (ret) {
4343                                 ctx->ctx_state = PFM_CTX_UNLOADED;
4344                                 ctx->ctx_task  = NULL;
4345                         }
4346                 }
4347         }
4348         return ret;
4349 }
4350 
4351 /*
4352  * in this function, we do not need to increase the use count
4353  * for the task via get_task_struct(), because we hold the
4354  * context lock. If the task were to disappear while having
4355  * a context attached, it would go through pfm_exit_thread()
4356  * which also grabs the context lock  and would therefore be blocked
4357  * until we are here.
4358  */
4359 static void pfm_flush_pmds(struct task_struct *, pfm_context_t *ctx);
4360 
4361 static int
4362 pfm_context_unload(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
4363 {
4364         struct task_struct *task = PFM_CTX_TASK(ctx);
4365         struct pt_regs *tregs;
4366         int prev_state, is_system;
4367         int ret;
4368 
4369         DPRINT(("ctx_state=%d task [%d]\n", ctx->ctx_state, task ? task_pid_nr(task) : -1));
4370 
4371         prev_state = ctx->ctx_state;
4372         is_system  = ctx->ctx_fl_system;
4373 
4374         /*
4375          * unload only when necessary
4376          */
4377         if (prev_state == PFM_CTX_UNLOADED) {
4378                 DPRINT(("ctx_state=%d, nothing to do\n", prev_state));
4379                 return 0;
4380         }
4381 
4382         /*
4383          * clear psr and dcr bits
4384          */
4385         ret = pfm_stop(ctx, NULL, 0, regs);
4386         if (ret) return ret;
4387 
4388         ctx->ctx_state = PFM_CTX_UNLOADED;
4389 
4390         /*
4391          * in system mode, we need to update the PMU directly
4392          * and the user level state of the caller, which may not
4393          * necessarily be the creator of the context.
4394          */
4395         if (is_system) {
4396 
4397                 /*
4398                  * Update cpuinfo
4399                  *
4400                  * local PMU is taken care of in pfm_stop()
4401                  */
4402                 PFM_CPUINFO_CLEAR(PFM_CPUINFO_SYST_WIDE);
4403                 PFM_CPUINFO_CLEAR(PFM_CPUINFO_EXCL_IDLE);
4404 
4405                 /*
4406                  * save PMDs in context
4407                  * release ownership
4408                  */
4409                 pfm_flush_pmds(current, ctx);
4410 
4411                 /*
4412                  * at this point we are done with the PMU
4413                  * so we can unreserve the resource.
4414                  */
4415                 if (prev_state != PFM_CTX_ZOMBIE) 
4416                         pfm_unreserve_session(ctx, 1 , ctx->ctx_cpu);
4417 
4418                 /*
4419                  * disconnect context from task
4420                  */
4421                 task->thread.pfm_context = NULL;
4422                 /*
4423                  * disconnect task from context
4424                  */
4425                 ctx->ctx_task = NULL;
4426 
4427                 /*
4428                  * There is nothing more to cleanup here.
4429                  */
4430                 return 0;
4431         }
4432 
4433         /*
4434          * per-task mode
4435          */
4436         tregs = task == current ? regs : task_pt_regs(task);
4437 
4438         if (task == current) {
4439                 /*
4440                  * cancel user level control
4441                  */
4442                 ia64_psr(regs)->sp = 1;
4443 
4444                 DPRINT(("setting psr.sp for [%d]\n", task_pid_nr(task)));
4445         }
4446         /*
4447          * save PMDs to context
4448          * release ownership
4449          */
4450         pfm_flush_pmds(task, ctx);
4451 
4452         /*
4453          * at this point we are done with the PMU
4454          * so we can unreserve the resource.
4455          *
4456          * when state was ZOMBIE, we have already unreserved.
4457          */
4458         if (prev_state != PFM_CTX_ZOMBIE) 
4459                 pfm_unreserve_session(ctx, 0 , ctx->ctx_cpu);
4460 
4461         /*
4462          * reset activation counter and psr
4463          */
4464         ctx->ctx_last_activation = PFM_INVALID_ACTIVATION;
4465         SET_LAST_CPU(ctx, -1);
4466 
4467         /*
4468          * PMU state will not be restored
4469          */
4470         task->thread.flags &= ~IA64_THREAD_PM_VALID;
4471 
4472         /*
4473          * break links between context and task
4474          */
4475         task->thread.pfm_context  = NULL;
4476         ctx->ctx_task             = NULL;
4477 
4478         PFM_SET_WORK_PENDING(task, 0);
4479 
4480         ctx->ctx_fl_trap_reason  = PFM_TRAP_REASON_NONE;
4481         ctx->ctx_fl_can_restart  = 0;
4482         ctx->ctx_fl_going_zombie = 0;
4483 
4484         DPRINT(("disconnected [%d] from context\n", task_pid_nr(task)));
4485 
4486         return 0;
4487 }
4488 
4489 
4490 /*
4491  * called only from exit_thread()
4492  * we come here only if the task has a context attached (loaded or masked)
4493  */
4494 void
4495 pfm_exit_thread(struct task_struct *task)
4496 {
4497         pfm_context_t *ctx;
4498         unsigned long flags;
4499         struct pt_regs *regs = task_pt_regs(task);
4500         int ret, state;
4501         int free_ok = 0;
4502 
4503         ctx = PFM_GET_CTX(task);
4504 
4505         PROTECT_CTX(ctx, flags);
4506 
4507         DPRINT(("state=%d task [%d]\n", ctx->ctx_state, task_pid_nr(task)));
4508 
4509         state = ctx->ctx_state;
4510         switch(state) {
4511                 case PFM_CTX_UNLOADED:
4512                         /*
4513                          * only comes to this function if pfm_context is not NULL, i.e., cannot
4514                          * be in unloaded state
4515                          */
4516                         printk(KERN_ERR "perfmon: pfm_exit_thread [%d] ctx unloaded\n", task_pid_nr(task));
4517                         break;
4518                 case PFM_CTX_LOADED:
4519                 case PFM_CTX_MASKED:
4520                         ret = pfm_context_unload(ctx, NULL, 0, regs);
4521                         if (ret) {
4522                                 printk(KERN_ERR "perfmon: pfm_exit_thread [%d] state=%d unload failed %d\n", task_pid_nr(task), state, ret);
4523                         }
4524                         DPRINT(("ctx unloaded for current state was %d\n", state));
4525 
4526                         pfm_end_notify_user(ctx);
4527                         break;
4528                 case PFM_CTX_ZOMBIE:
4529                         ret = pfm_context_unload(ctx, NULL, 0, regs);
4530                         if (ret) {
4531                                 printk(KERN_ERR "perfmon: pfm_exit_thread [%d] state=%d unload failed %d\n", task_pid_nr(task), state, ret);
4532                         }
4533                         free_ok = 1;
4534                         break;
4535                 default:
4536                         printk(KERN_ERR "perfmon: pfm_exit_thread [%d] unexpected state=%d\n", task_pid_nr(task), state);
4537                         break;
4538         }
4539         UNPROTECT_CTX(ctx, flags);
4540 
4541         { u64 psr = pfm_get_psr();
4542           BUG_ON(psr & (IA64_PSR_UP|IA64_PSR_PP));
4543           BUG_ON(GET_PMU_OWNER());
4544           BUG_ON(ia64_psr(regs)->up);
4545           BUG_ON(ia64_psr(regs)->pp);
4546         }
4547 
4548         /*
4549          * All memory free operations (especially for vmalloc'ed memory)
4550          * MUST be done with interrupts ENABLED.
4551          */
4552         if (free_ok) pfm_context_free(ctx);
4553 }
4554 
4555 /*
4556  * functions MUST be listed in the increasing order of their index (see permfon.h)
4557  */
4558 #define PFM_CMD(name, flags, arg_count, arg_type, getsz) { name, #name, flags, arg_count, sizeof(arg_type), getsz }
4559 #define PFM_CMD_S(name, flags) { name, #name, flags, 0, 0, NULL }
4560 #define PFM_CMD_PCLRWS  (PFM_CMD_FD|PFM_CMD_ARG_RW|PFM_CMD_STOP)
4561 #define PFM_CMD_PCLRW   (PFM_CMD_FD|PFM_CMD_ARG_RW)
4562 #define PFM_CMD_NONE    { NULL, "no-cmd", 0, 0, 0, NULL}
4563 
4564 static pfm_cmd_desc_t pfm_cmd_tab[]={
4565 /* 0  */PFM_CMD_NONE,
4566 /* 1  */PFM_CMD(pfm_write_pmcs, PFM_CMD_PCLRWS, PFM_CMD_ARG_MANY, pfarg_reg_t, NULL),
4567 /* 2  */PFM_CMD(pfm_write_pmds, PFM_CMD_PCLRWS, PFM_CMD_ARG_MANY, pfarg_reg_t, NULL),
4568 /* 3  */PFM_CMD(pfm_read_pmds, PFM_CMD_PCLRWS, PFM_CMD_ARG_MANY, pfarg_reg_t, NULL),
4569 /* 4  */PFM_CMD_S(pfm_stop, PFM_CMD_PCLRWS),
4570 /* 5  */PFM_CMD_S(pfm_start, PFM_CMD_PCLRWS),
4571 /* 6  */PFM_CMD_NONE,
4572 /* 7  */PFM_CMD_NONE,
4573 /* 8  */PFM_CMD(pfm_context_create, PFM_CMD_ARG_RW, 1, pfarg_context_t, pfm_ctx_getsize),
4574 /* 9  */PFM_CMD_NONE,
4575 /* 10 */PFM_CMD_S(pfm_restart, PFM_CMD_PCLRW),
4576 /* 11 */PFM_CMD_NONE,
4577 /* 12 */PFM_CMD(pfm_get_features, PFM_CMD_ARG_RW, 1, pfarg_features_t, NULL),
4578 /* 13 */PFM_CMD(pfm_debug, 0, 1, unsigned int, NULL),
4579 /* 14 */PFM_CMD_NONE,
4580 /* 15 */PFM_CMD(pfm_get_pmc_reset, PFM_CMD_ARG_RW, PFM_CMD_ARG_MANY, pfarg_reg_t, NULL),
4581 /* 16 */PFM_CMD(pfm_context_load, PFM_CMD_PCLRWS, 1, pfarg_load_t, NULL),
4582 /* 17 */PFM_CMD_S(pfm_context_unload, PFM_CMD_PCLRWS),
4583 /* 18 */PFM_CMD_NONE,
4584 /* 19 */PFM_CMD_NONE,
4585 /* 20 */PFM_CMD_NONE,
4586 /* 21 */PFM_CMD_NONE,
4587 /* 22 */PFM_CMD_NONE,
4588 /* 23 */PFM_CMD_NONE,
4589 /* 24 */PFM_CMD_NONE,
4590 /* 25 */PFM_CMD_NONE,
4591 /* 26 */PFM_CMD_NONE,
4592 /* 27 */PFM_CMD_NONE,
4593 /* 28 */PFM_CMD_NONE,
4594 /* 29 */PFM_CMD_NONE,
4595 /* 30 */PFM_CMD_NONE,
4596 /* 31 */PFM_CMD_NONE,
4597 /* 32 */PFM_CMD(pfm_write_ibrs, PFM_CMD_PCLRWS, PFM_CMD_ARG_MANY, pfarg_dbreg_t, NULL),
4598 /* 33 */PFM_CMD(pfm_write_dbrs, PFM_CMD_PCLRWS, PFM_CMD_ARG_MANY, pfarg_dbreg_t, NULL)
4599 };
4600 #define PFM_CMD_COUNT   (sizeof(pfm_cmd_tab)/sizeof(pfm_cmd_desc_t))
4601 
4602 static int
4603 pfm_check_task_state(pfm_context_t *ctx, int cmd, unsigned long flags)
4604 {
4605         struct task_struct *task;
4606         int state, old_state;
4607 
4608 recheck:
4609         state = ctx->ctx_state;
4610         task  = ctx->ctx_task;
4611 
4612         if (task == NULL) {
4613                 DPRINT(("context %d no task, state=%d\n", ctx->ctx_fd, state));
4614                 return 0;
4615         }
4616 
4617         DPRINT(("context %d state=%d [%d] task_state=%ld must_stop=%d\n",
4618                 ctx->ctx_fd,
4619                 state,
4620                 task_pid_nr(task),
4621                 task->state, PFM_CMD_STOPPED(cmd)));
4622 
4623         /*
4624          * self-monitoring always ok.
4625          *
4626          * for system-wide the caller can either be the creator of the
4627          * context (to one to which the context is attached to) OR
4628          * a task running on the same CPU as the session.
4629          */
4630         if (task == current || ctx->ctx_fl_system) return 0;
4631 
4632         /*
4633          * we are monitoring another thread
4634          */
4635         switch(state) {
4636                 case PFM_CTX_UNLOADED:
4637                         /*
4638                          * if context is UNLOADED we are safe to go
4639                          */
4640                         return 0;
4641                 case PFM_CTX_ZOMBIE:
4642                         /*
4643                          * no command can operate on a zombie context
4644                          */
4645                         DPRINT(("cmd %d state zombie cannot operate on context\n", cmd));
4646                         return -EINVAL;
4647                 case PFM_CTX_MASKED:
4648                         /*
4649                          * PMU state has been saved to software even though
4650                          * the thread may still be running.
4651                          */
4652                         if (cmd != PFM_UNLOAD_CONTEXT) return 0;
4653         }
4654 
4655         /*
4656          * context is LOADED or MASKED. Some commands may need to have 
4657          * the task stopped.
4658          *
4659          * We could lift this restriction for UP but it would mean that
4660          * the user has no guarantee the task would not run between
4661          * two successive calls to perfmonctl(). That's probably OK.
4662          * If this user wants to ensure the task does not run, then
4663          * the task must be stopped.
4664          */
4665         if (PFM_CMD_STOPPED(cmd)) {
4666                 if (!task_is_stopped_or_traced(task)) {
4667                         DPRINT(("[%d] task not in stopped state\n", task_pid_nr(task)));
4668                         return -EBUSY;
4669                 }
4670                 /*
4671                  * task is now stopped, wait for ctxsw out
4672                  *
4673                  * This is an interesting point in the code.
4674                  * We need to unprotect the context because
4675                  * the pfm_save_regs() routines needs to grab
4676                  * the same lock. There are danger in doing
4677                  * this because it leaves a window open for
4678                  * another task to get access to the context
4679                  * and possibly change its state. The one thing
4680                  * that is not possible is for the context to disappear
4681                  * because we are protected by the VFS layer, i.e.,
4682                  * get_fd()/put_fd().
4683                  */
4684                 old_state = state;
4685 
4686                 UNPROTECT_CTX(ctx, flags);
4687 
4688                 wait_task_inactive(task, 0);
4689 
4690                 PROTECT_CTX(ctx, flags);
4691 
4692                 /*
4693                  * we must recheck to verify if state has changed
4694                  */
4695                 if (ctx->ctx_state != old_state) {
4696                         DPRINT(("old_state=%d new_state=%d\n", old_state, ctx->ctx_state));
4697                         goto recheck;
4698                 }
4699         }
4700         return 0;
4701 }
4702 
4703 /*
4704  * system-call entry point (must return long)
4705  */
4706 asmlinkage long
4707 sys_perfmonctl (int fd, int cmd, void __user *arg, int count)
4708 {
4709         struct fd f = {NULL, 0};
4710         pfm_context_t *ctx = NULL;
4711         unsigned long flags = 0UL;
4712         void *args_k = NULL;
4713         long ret; /* will expand int return types */
4714         size_t base_sz, sz, xtra_sz = 0;
4715         int narg, completed_args = 0, call_made = 0, cmd_flags;
4716         int (*func)(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs);
4717         int (*getsize)(void *arg, size_t *sz);
4718 #define PFM_MAX_ARGSIZE 4096
4719 
4720         /*
4721          * reject any call if perfmon was disabled at initialization
4722          */
4723         if (unlikely(pmu_conf == NULL)) return -ENOSYS;
4724 
4725         if (unlikely(cmd < 0 || cmd >= PFM_CMD_COUNT)) {
4726                 DPRINT(("invalid cmd=%d\n", cmd));
4727                 return -EINVAL;
4728         }
4729 
4730         func      = pfm_cmd_tab[cmd].cmd_func;
4731         narg      = pfm_cmd_tab[cmd].cmd_narg;
4732         base_sz   = pfm_cmd_tab[cmd].cmd_argsize;
4733         getsize   = pfm_cmd_tab[cmd].cmd_getsize;
4734         cmd_flags = pfm_cmd_tab[cmd].cmd_flags;
4735 
4736         if (unlikely(func == NULL)) {
4737                 DPRINT(("invalid cmd=%d\n", cmd));
4738                 return -EINVAL;
4739         }
4740 
4741         DPRINT(("cmd=%s idx=%d narg=0x%x argsz=%lu count=%d\n",
4742                 PFM_CMD_NAME(cmd),
4743                 cmd,
4744                 narg,
4745                 base_sz,
4746                 count));
4747 
4748         /*
4749          * check if number of arguments matches what the command expects
4750          */
4751         if (unlikely((narg == PFM_CMD_ARG_MANY && count <= 0) || (narg > 0 && narg != count)))
4752                 return -EINVAL;
4753 
4754 restart_args:
4755         sz = xtra_sz + base_sz*count;
4756         /*
4757          * limit abuse to min page size
4758          */
4759         if (unlikely(sz > PFM_MAX_ARGSIZE)) {
4760                 printk(KERN_ERR "perfmon: [%d] argument too big %lu\n", task_pid_nr(current), sz);
4761                 return -E2BIG;
4762         }
4763 
4764         /*
4765          * allocate default-sized argument buffer
4766          */
4767         if (likely(count && args_k == NULL)) {
4768                 args_k = kmalloc(PFM_MAX_ARGSIZE, GFP_KERNEL);
4769                 if (args_k == NULL) return -ENOMEM;
4770         }
4771 
4772         ret = -EFAULT;
4773 
4774         /*
4775          * copy arguments
4776          *
4777          * assume sz = 0 for command without parameters
4778          */
4779         if (sz && copy_from_user(args_k, arg, sz)) {
4780                 DPRINT(("cannot copy_from_user %lu bytes @%p\n", sz, arg));
4781                 goto error_args;
4782         }
4783 
4784         /*
4785          * check if command supports extra parameters
4786          */
4787         if (completed_args == 0 && getsize) {
4788                 /*
4789                  * get extra parameters size (based on main argument)
4790                  */
4791                 ret = (*getsize)(args_k, &xtra_sz);
4792                 if (ret) goto error_args;
4793 
4794                 completed_args = 1;
4795 
4796                 DPRINT(("restart_args sz=%lu xtra_sz=%lu\n", sz, xtra_sz));
4797 
4798                 /* retry if necessary */
4799                 if (likely(xtra_sz)) goto restart_args;
4800         }
4801 
4802         if (unlikely((cmd_flags & PFM_CMD_FD) == 0)) goto skip_fd;
4803 
4804         ret = -EBADF;
4805 
4806         f = fdget(fd);
4807         if (unlikely(f.file == NULL)) {
4808                 DPRINT(("invalid fd %d\n", fd));
4809                 goto error_args;
4810         }
4811         if (unlikely(PFM_IS_FILE(f.file) == 0)) {
4812                 DPRINT(("fd %d not related to perfmon\n", fd));
4813                 goto error_args;
4814         }
4815 
4816         ctx = f.file->private_data;
4817         if (unlikely(ctx == NULL)) {
4818                 DPRINT(("no context for fd %d\n", fd));
4819                 goto error_args;
4820         }
4821         prefetch(&ctx->ctx_state);
4822 
4823         PROTECT_CTX(ctx, flags);
4824 
4825         /*
4826          * check task is stopped
4827          */
4828         ret = pfm_check_task_state(ctx, cmd, flags);
4829         if (unlikely(ret)) goto abort_locked;
4830 
4831 skip_fd:
4832         ret = (*func)(ctx, args_k, count, task_pt_regs(current));
4833 
4834         call_made = 1;
4835 
4836 abort_locked:
4837         if (likely(ctx)) {
4838                 DPRINT(("context unlocked\n"));
4839                 UNPROTECT_CTX(ctx, flags);
4840         }
4841 
4842         /* copy argument back to user, if needed */
4843         if (call_made && PFM_CMD_RW_ARG(cmd) && copy_to_user(arg, args_k, base_sz*count)) ret = -EFAULT;
4844 
4845 error_args:
4846         if (f.file)
4847                 fdput(f);
4848 
4849         kfree(args_k);
4850 
4851         DPRINT(("cmd=%s ret=%ld\n", PFM_CMD_NAME(cmd), ret));
4852 
4853         return ret;
4854 }
4855 
4856 static void
4857 pfm_resume_after_ovfl(pfm_context_t *ctx, unsigned long ovfl_regs, struct pt_regs *regs)
4858 {
4859         pfm_buffer_fmt_t *fmt = ctx->ctx_buf_fmt;
4860         pfm_ovfl_ctrl_t rst_ctrl;
4861         int state;
4862         int ret = 0;
4863 
4864         state = ctx->ctx_state;
4865         /*
4866          * Unlock sampling buffer and reset index atomically
4867          * XXX: not really needed when blocking
4868          */
4869         if (CTX_HAS_SMPL(ctx)) {
4870 
4871                 rst_ctrl.bits.mask_monitoring = 0;
4872                 rst_ctrl.bits.reset_ovfl_pmds = 0;
4873 
4874                 if (state == PFM_CTX_LOADED)
4875                         ret = pfm_buf_fmt_restart_active(fmt, current, &rst_ctrl, ctx->ctx_smpl_hdr, regs);
4876                 else
4877                         ret = pfm_buf_fmt_restart(fmt, current, &rst_ctrl, ctx->ctx_smpl_hdr, regs);
4878         } else {
4879                 rst_ctrl.bits.mask_monitoring = 0;
4880                 rst_ctrl.bits.reset_ovfl_pmds = 1;
4881         }
4882 
4883         if (ret == 0) {
4884                 if (rst_ctrl.bits.reset_ovfl_pmds) {
4885                         pfm_reset_regs(ctx, &ovfl_regs, PFM_PMD_LONG_RESET);
4886                 }
4887                 if (rst_ctrl.bits.mask_monitoring == 0) {
4888                         DPRINT(("resuming monitoring\n"));
4889                         if (ctx->ctx_state == PFM_CTX_MASKED) pfm_restore_monitoring(current);
4890                 } else {
4891                         DPRINT(("stopping monitoring\n"));
4892                         //pfm_stop_monitoring(current, regs);
4893                 }
4894                 ctx->ctx_state = PFM_CTX_LOADED;
4895         }
4896 }
4897 
4898 /*
4899  * context MUST BE LOCKED when calling
4900  * can only be called for current
4901  */
4902 static void
4903 pfm_context_force_terminate(pfm_context_t *ctx, struct pt_regs *regs)
4904 {
4905         int ret;
4906 
4907         DPRINT(("entering for [%d]\n", task_pid_nr(current)));
4908 
4909         ret = pfm_context_unload(ctx, NULL, 0, regs);
4910         if (ret) {
4911                 printk(KERN_ERR "pfm_context_force_terminate: [%d] unloaded failed with %d\n", task_pid_nr(current), ret);
4912         }
4913 
4914         /*
4915          * and wakeup controlling task, indicating we are now disconnected
4916          */
4917         wake_up_interruptible(&ctx->ctx_zombieq);
4918 
4919         /*
4920          * given that context is still locked, the controlling
4921          * task will only get access when we return from
4922          * pfm_handle_work().
4923          */
4924 }
4925 
4926 static int pfm_ovfl_notify_user(pfm_context_t *ctx, unsigned long ovfl_pmds);
4927 
4928  /*
4929   * pfm_handle_work() can be called with interrupts enabled
4930   * (TIF_NEED_RESCHED) or disabled. The down_interruptible
4931   * call may sleep, therefore we must re-enable interrupts
4932   * to avoid deadlocks. It is safe to do so because this function
4933   * is called ONLY when returning to user level (pUStk=1), in which case
4934   * there is no risk of kernel stack overflow due to deep
4935   * interrupt nesting.
4936   */
4937 void
4938 pfm_handle_work(void)
4939 {
4940         pfm_context_t *ctx;
4941         struct pt_regs *regs;
4942         unsigned long flags, dummy_flags;
4943         unsigned long ovfl_regs;
4944         unsigned int reason;
4945         int ret;
4946 
4947         ctx = PFM_GET_CTX(current);
4948         if (ctx == NULL) {
4949                 printk(KERN_ERR "perfmon: [%d] has no PFM context\n",
4950                         task_pid_nr(current));
4951                 return;
4952         }
4953 
4954         PROTECT_CTX(ctx, flags);
4955 
4956         PFM_SET_WORK_PENDING(current, 0);
4957 
4958         regs = task_pt_regs(current);
4959 
4960         /*
4961          * extract reason for being here and clear
4962          */
4963         reason = ctx->ctx_fl_trap_reason;
4964         ctx->ctx_fl_trap_reason = PFM_TRAP_REASON_NONE;
4965         ovfl_regs = ctx->ctx_ovfl_regs[0];
4966 
4967         DPRINT(("reason=%d state=%d\n", reason, ctx->ctx_state));
4968 
4969         /*
4970          * must be done before we check for simple-reset mode
4971          */
4972         if (ctx->ctx_fl_going_zombie || ctx->ctx_state == PFM_CTX_ZOMBIE)
4973                 goto do_zombie;
4974 
4975         //if (CTX_OVFL_NOBLOCK(ctx)) goto skip_blocking;
4976         if (reason == PFM_TRAP_REASON_RESET)
4977                 goto skip_blocking;
4978 
4979         /*
4980          * restore interrupt mask to what it was on entry.
4981          * Could be enabled/diasbled.
4982          */
4983         UNPROTECT_CTX(ctx, flags);
4984 
4985         /*
4986          * force interrupt enable because of down_interruptible()
4987          */
4988         local_irq_enable();
4989 
4990         DPRINT(("before block sleeping\n"));
4991 
4992         /*
4993          * may go through without blocking on SMP systems
4994          * if restart has been received already by the time we call down()
4995          */
4996         ret = wait_for_completion_interruptible(&ctx->ctx_restart_done);
4997 
4998         DPRINT(("after block sleeping ret=%d\n", ret));
4999 
5000         /*
5001          * lock context and mask interrupts again
5002          * We save flags into a dummy because we may have
5003          * altered interrupts mask compared to entry in this
5004          * function.
5005          */
5006         PROTECT_CTX(ctx, dummy_flags);
5007 
5008         /*
5009          * we need to read the ovfl_regs only after wake-up
5010          * because we may have had pfm_write_pmds() in between
5011          * and that can changed PMD values and therefore 
5012          * ovfl_regs is reset for these new PMD values.
5013          */
5014         ovfl_regs = ctx->ctx_ovfl_regs[0];
5015 
5016         if (ctx->ctx_fl_going_zombie) {
5017 do_zombie:
5018                 DPRINT(("context is zombie, bailing out\n"));
5019                 pfm_context_force_terminate(ctx, regs);
5020                 goto nothing_to_do;
5021         }
5022         /*
5023          * in case of interruption of down() we don't restart anything
5024          */
5025         if (ret < 0)
5026                 goto nothing_to_do;
5027 
5028 skip_blocking:
5029         pfm_resume_after_ovfl(ctx, ovfl_regs, regs);
5030         ctx->ctx_ovfl_regs[0] = 0UL;
5031 
5032 nothing_to_do:
5033         /*
5034          * restore flags as they were upon entry
5035          */
5036         UNPROTECT_CTX(ctx, flags);
5037 }
5038 
5039 static int
5040 pfm_notify_user(pfm_context_t *ctx, pfm_msg_t *msg)
5041 {
5042         if (ctx->ctx_state == PFM_CTX_ZOMBIE) {
5043                 DPRINT(("ignoring overflow notification, owner is zombie\n"));
5044                 return 0;
5045         }
5046 
5047         DPRINT(("waking up somebody\n"));
5048 
5049         if (msg) wake_up_interruptible(&ctx->ctx_msgq_wait);
5050 
5051         /*
5052          * safe, we are not in intr handler, nor in ctxsw when
5053          * we come here
5054          */
5055         kill_fasync (&ctx->ctx_async_queue, SIGIO, POLL_IN);
5056 
5057         return 0;
5058 }
5059 
5060 static int
5061 pfm_ovfl_notify_user(pfm_context_t *ctx, unsigned long ovfl_pmds)
5062 {
5063         pfm_msg_t *msg = NULL;
5064 
5065         if (ctx->ctx_fl_no_msg == 0) {
5066                 msg = pfm_get_new_msg(ctx);
5067                 if (msg == NULL) {
5068                         printk(KERN_ERR "perfmon: pfm_ovfl_notify_user no more notification msgs\n");
5069                         return -1;
5070                 }
5071 
5072                 msg->pfm_ovfl_msg.msg_type         = PFM_MSG_OVFL;
5073                 msg->pfm_ovfl_msg.msg_ctx_fd       = ctx->ctx_fd;
5074                 msg->pfm_ovfl_msg.msg_active_set   = 0;
5075                 msg->pfm_ovfl_msg.msg_ovfl_pmds[0] = ovfl_pmds;
5076                 msg->pfm_ovfl_msg.msg_ovfl_pmds[1] = 0UL;
5077                 msg->pfm_ovfl_msg.msg_ovfl_pmds[2] = 0UL;
5078                 msg->pfm_ovfl_msg.msg_ovfl_pmds[3] = 0UL;
5079                 msg->pfm_ovfl_msg.msg_tstamp       = 0UL;
5080         }
5081 
5082         DPRINT(("ovfl msg: msg=%p no_msg=%d fd=%d ovfl_pmds=0x%lx\n",
5083                 msg,
5084                 ctx->ctx_fl_no_msg,
5085                 ctx->ctx_fd,
5086                 ovfl_pmds));
5087 
5088         return pfm_notify_user(ctx, msg);
5089 }
5090 
5091 static int
5092 pfm_end_notify_user(pfm_context_t *ctx)
5093 {
5094         pfm_msg_t *msg;
5095 
5096         msg = pfm_get_new_msg(ctx);
5097         if (msg == NULL) {
5098                 printk(KERN_ERR "perfmon: pfm_end_notify_user no more notification msgs\n");
5099                 return -1;
5100         }
5101         /* no leak */
5102         memset(msg, 0, sizeof(*msg));
5103 
5104         msg->pfm_end_msg.msg_type    = PFM_MSG_END;
5105         msg->pfm_end_msg.msg_ctx_fd  = ctx->ctx_fd;
5106         msg->pfm_ovfl_msg.msg_tstamp = 0UL;
5107 
5108         DPRINT(("end msg: msg=%p no_msg=%d ctx_fd=%d\n",
5109                 msg,
5110                 ctx->ctx_fl_no_msg,
5111                 ctx->ctx_fd));
5112 
5113         return pfm_notify_user(ctx, msg);
5114 }
5115 
5116 /*
5117  * main overflow processing routine.
5118  * it can be called from the interrupt path or explicitly during the context switch code
5119  */
5120 static void pfm_overflow_handler(struct task_struct *task, pfm_context_t *ctx,
5121                                 unsigned long pmc0, struct pt_regs *regs)
5122 {
5123         pfm_ovfl_arg_t *ovfl_arg;
5124         unsigned long mask;
5125         unsigned long old_val, ovfl_val, new_val;
5126         unsigned long ovfl_notify = 0UL, ovfl_pmds = 0UL, smpl_pmds = 0UL, reset_pmds;
5127         unsigned long tstamp;
5128         pfm_ovfl_ctrl_t ovfl_ctrl;
5129         unsigned int i, has_smpl;
5130         int must_notify = 0;
5131 
5132         if (unlikely(ctx->ctx_state == PFM_CTX_ZOMBIE)) goto stop_monitoring;
5133 
5134         /*
5135          * sanity test. Should never happen
5136          */
5137         if (unlikely((pmc0 & 0x1) == 0)) goto sanity_check;
5138 
5139         tstamp   = ia64_get_itc();
5140         mask     = pmc0 >> PMU_FIRST_COUNTER;
5141         ovfl_val = pmu_conf->ovfl_val;
5142         has_smpl = CTX_HAS_SMPL(ctx);
5143 
5144         DPRINT_ovfl(("pmc0=0x%lx pid=%d iip=0x%lx, %s "
5145                      "used_pmds=0x%lx\n",
5146                         pmc0,
5147                         task ? task_pid_nr(task): -1,
5148                         (regs ? regs->cr_iip : 0),
5149                         CTX_OVFL_NOBLOCK(ctx) ? "nonblocking" : "blocking",
5150                         ctx->ctx_used_pmds[0]));
5151 
5152 
5153         /*
5154          * first we update the virtual counters
5155          * assume there was a prior ia64_srlz_d() issued
5156          */
5157         for (i = PMU_FIRST_COUNTER; mask ; i++, mask >>= 1) {
5158 
5159                 /* skip pmd which did not overflow */
5160                 if ((mask & 0x1) == 0) continue;
5161 
5162                 /*
5163                  * Note that the pmd is not necessarily 0 at this point as qualified events
5164                  * may have happened before the PMU was frozen. The residual count is not
5165                  * taken into consideration here but will be with any read of the pmd via
5166                  * pfm_read_pmds().
5167                  */
5168                 old_val              = new_val = ctx->ctx_pmds[i].val;
5169                 new_val             += 1 + ovfl_val;
5170                 ctx->ctx_pmds[i].val = new_val;
5171 
5172                 /*
5173                  * check for overflow condition
5174                  */
5175                 if (likely(old_val > new_val)) {
5176                         ovfl_pmds |= 1UL << i;
5177                         if (PMC_OVFL_NOTIFY(ctx, i)) ovfl_notify |= 1UL << i;
5178                 }
5179 
5180                 DPRINT_ovfl(("ctx_pmd[%d].val=0x%lx old_val=0x%lx pmd=0x%lx ovfl_pmds=0x%lx ovfl_notify=0x%lx\n",
5181                         i,
5182                         new_val,
5183                         old_val,
5184                         ia64_get_pmd(i) & ovfl_val,
5185                         ovfl_pmds,
5186                         ovfl_notify));
5187         }
5188 
5189         /*
5190          * there was no 64-bit overflow, nothing else to do
5191          */
5192         if (ovfl_pmds == 0UL) return;
5193 
5194         /* 
5195          * reset all control bits
5196          */
5197         ovfl_ctrl.val = 0;
5198         reset_pmds    = 0UL;
5199 
5200         /*
5201          * if a sampling format module exists, then we "cache" the overflow by 
5202          * calling the module's handler() routine.
5203          */
5204         if (has_smpl) {
5205                 unsigned long start_cycles, end_cycles;
5206                 unsigned long pmd_mask;
5207                 int j, k, ret = 0;
5208                 int this_cpu = smp_processor_id();
5209 
5210                 pmd_mask = ovfl_pmds >> PMU_FIRST_COUNTER;
5211                 ovfl_arg = &ctx->ctx_ovfl_arg;
5212 
5213                 prefetch(ctx->ctx_smpl_hdr);
5214 
5215                 for(i=PMU_FIRST_COUNTER; pmd_mask && ret == 0; i++, pmd_mask >>=1) {
5216 
5217                         mask = 1UL << i;
5218 
5219                         if ((pmd_mask & 0x1) == 0) continue;
5220 
5221                         ovfl_arg->ovfl_pmd      = (unsigned char )i;
5222                         ovfl_arg->ovfl_notify   = ovfl_notify & mask ? 1 : 0;
5223                         ovfl_arg->active_set    = 0;
5224                         ovfl_arg->ovfl_ctrl.val = 0; /* module must fill in all fields */
5225                         ovfl_arg->smpl_pmds[0]  = smpl_pmds = ctx->ctx_pmds[i].smpl_pmds[0];
5226 
5227                         ovfl_arg->pmd_value      = ctx->ctx_pmds[i].val;
5228                         ovfl_arg->pmd_last_reset = ctx->ctx_pmds[i].lval;
5229                         ovfl_arg->pmd_eventid    = ctx->ctx_pmds[i].eventid;
5230 
5231                         /*
5232                          * copy values of pmds of interest. Sampling format may copy them
5233                          * into sampling buffer.
5234                          */
5235                         if (smpl_pmds) {
5236                                 for(j=0, k=0; smpl_pmds; j++, smpl_pmds >>=1) {
5237                                         if ((smpl_pmds & 0x1) == 0) continue;
5238                                         ovfl_arg->smpl_pmds_values[k++] = PMD_IS_COUNTING(j) ?  pfm_read_soft_counter(ctx, j) : ia64_get_pmd(j);
5239                                         DPRINT_ovfl(("smpl_pmd[%d]=pmd%u=0x%lx\n", k-1, j, ovfl_arg->smpl_pmds_values[k-1]));
5240                                 }
5241                         }
5242 
5243                         pfm_stats[this_cpu].pfm_smpl_handler_calls++;
5244 
5245                         start_cycles = ia64_get_itc();
5246 
5247                         /*
5248                          * call custom buffer format record (handler) routine
5249                          */
5250                         ret = (*ctx->ctx_buf_fmt->fmt_handler)(task, ctx->ctx_smpl_hdr, ovfl_arg, regs, tstamp);
5251 
5252                         end_cycles = ia64_get_itc();
5253 
5254                         /*
5255                          * For those controls, we take the union because they have
5256                          * an all or nothing behavior.
5257                          */
5258                         ovfl_ctrl.bits.notify_user     |= ovfl_arg->ovfl_ctrl.bits.notify_user;
5259                         ovfl_ctrl.bits.block_task      |= ovfl_arg->ovfl_ctrl.bits.block_task;
5260                         ovfl_ctrl.bits.mask_monitoring |= ovfl_arg->ovfl_ctrl.bits.mask_monitoring;
5261                         /*
5262                          * build the bitmask of pmds to reset now
5263                          */
5264                         if (ovfl_arg->ovfl_ctrl.bits.reset_ovfl_pmds) reset_pmds |= mask;
5265 
5266                         pfm_stats[this_cpu].pfm_smpl_handler_cycles += end_cycles - start_cycles;
5267                 }
5268                 /*
5269                  * when the module cannot handle the rest of the overflows, we abort right here
5270                  */
5271                 if (ret && pmd_mask) {
5272                         DPRINT(("handler aborts leftover ovfl_pmds=0x%lx\n",
5273                                 pmd_mask<<PMU_FIRST_COUNTER));
5274                 }
5275                 /*
5276                  * remove the pmds we reset now from the set of pmds to reset in pfm_restart()
5277                  */
5278                 ovfl_pmds &= ~reset_pmds;
5279         } else {
5280                 /*
5281                  * when no sampling module is used, then the default
5282                  * is to notify on overflow if requested by user
5283                  */
5284                 ovfl_ctrl.bits.notify_user     = ovfl_notify ? 1 : 0;
5285                 ovfl_ctrl.bits.block_task      = ovfl_notify ? 1 : 0;
5286                 ovfl_ctrl.bits.mask_monitoring = ovfl_notify ? 1 : 0; /* XXX: change for saturation */
5287                 ovfl_ctrl.bits.reset_ovfl_pmds = ovfl_notify ? 0 : 1;
5288                 /*
5289                  * if needed, we reset all overflowed pmds
5290                  */
5291                 if (ovfl_notify == 0) reset_pmds = ovfl_pmds;
5292         }
5293 
5294         DPRINT_ovfl(("ovfl_pmds=0x%lx reset_pmds=0x%lx\n", ovfl_pmds, reset_pmds));
5295 
5296         /*
5297          * reset the requested PMD registers using the short reset values
5298          */
5299         if (reset_pmds) {
5300                 unsigned long bm = reset_pmds;
5301                 pfm_reset_regs(ctx, &bm, PFM_PMD_SHORT_RESET);
5302         }
5303 
5304         if (ovfl_notify && ovfl_ctrl.bits.notify_user) {
5305                 /*
5306                  * keep track of what to reset when unblocking
5307                  */
5308                 ctx->ctx_ovfl_regs[0] = ovfl_pmds;
5309 
5310                 /*
5311                  * check for blocking context 
5312                  */
5313                 if (CTX_OVFL_NOBLOCK(ctx) == 0 && ovfl_ctrl.bits.block_task) {
5314 
5315                         ctx->ctx_fl_trap_reason = PFM_TRAP_REASON_BLOCK;
5316 
5317                         /*
5318                          * set the perfmon specific checking pending work for the task
5319                          */
5320                         PFM_SET_WORK_PENDING(task, 1);
5321 
5322                         /*
5323                          * when coming from ctxsw, current still points to the
5324                          * previous task, therefore we must work with task and not current.
5325                          */
5326                         set_notify_resume(task);
5327                 }
5328                 /*
5329                  * defer until state is changed (shorten spin window). the context is locked
5330                  * anyway, so the signal receiver would come spin for nothing.
5331                  */
5332                 must_notify = 1;
5333         }
5334 
5335         DPRINT_ovfl(("owner [%d] pending=%ld reason=%u ovfl_pmds=0x%lx ovfl_notify=0x%lx masked=%d\n",
5336                         GET_PMU_OWNER() ? task_pid_nr(GET_PMU_OWNER()) : -1,
5337                         PFM_GET_WORK_PENDING(task),
5338                         ctx->ctx_fl_trap_reason,
5339                         ovfl_pmds,
5340                         ovfl_notify,
5341                         ovfl_ctrl.bits.mask_monitoring ? 1 : 0));
5342         /*
5343          * in case monitoring must be stopped, we toggle the psr bits
5344          */
5345         if (ovfl_ctrl.bits.mask_monitoring) {
5346                 pfm_mask_monitoring(task);
5347                 ctx->ctx_state = PFM_CTX_MASKED;
5348                 ctx->ctx_fl_can_restart = 1;
5349         }
5350 
5351         /*
5352          * send notification now
5353          */
5354         if (must_notify) pfm_ovfl_notify_user(ctx, ovfl_notify);
5355 
5356         return;
5357 
5358 sanity_check:
5359         printk(KERN_ERR "perfmon: CPU%d overflow handler [%d] pmc0=0x%lx\n",
5360                         smp_processor_id(),
5361                         task ? task_pid_nr(task) : -1,
5362                         pmc0);
5363         return;
5364 
5365 stop_monitoring:
5366         /*
5367          * in SMP, zombie context is never restored but reclaimed in pfm_load_regs().
5368          * Moreover, zombies are also reclaimed in pfm_save_regs(). Therefore we can
5369          * come here as zombie only if the task is the current task. In which case, we
5370          * can access the PMU  hardware directly.
5371          *
5372          * Note that zombies do have PM_VALID set. So here we do the minimal.
5373          *
5374          * In case the context was zombified it could not be reclaimed at the time
5375          * the monitoring program exited. At this point, the PMU reservation has been
5376          * returned, the sampiing buffer has been freed. We must convert this call
5377          * into a spurious interrupt. However, we must also avoid infinite overflows
5378          * by stopping monitoring for this task. We can only come here for a per-task
5379          * context. All we need to do is to stop monitoring using the psr bits which
5380          * are always task private. By re-enabling secure montioring, we ensure that
5381          * the monitored task will not be able to re-activate monitoring.
5382          * The task will eventually be context switched out, at which point the context
5383          * will be reclaimed (that includes releasing ownership of the PMU).
5384          *
5385          * So there might be a window of time where the number of per-task session is zero
5386          * yet one PMU might have a owner and get at most one overflow interrupt for a zombie
5387          * context. This is safe because if a per-task session comes in, it will push this one
5388          * out and by the virtue on pfm_save_regs(), this one will disappear. If a system wide
5389          * session is force on that CPU, given that we use task pinning, pfm_save_regs() will
5390          * also push our zombie context out.
5391          *
5392          * Overall pretty hairy stuff....
5393          */
5394         DPRINT(("ctx is zombie for [%d], converted to spurious\n", task ? task_pid_nr(task): -1));
5395         pfm_clear_psr_up();
5396         ia64_psr(regs)->up = 0;
5397         ia64_psr(regs)->sp = 1;
5398         return;
5399 }
5400 
5401 static int
5402 pfm_do_interrupt_handler(void *arg, struct pt_regs *regs)
5403 {
5404         struct task_struct *task;
5405         pfm_context_t *ctx;
5406         unsigned long flags;
5407         u64 pmc0;
5408         int this_cpu = smp_processor_id();
5409         int retval = 0;
5410 
5411         pfm_stats[this_cpu].pfm_ovfl_intr_count++;
5412 
5413         /*
5414          * srlz.d done before arriving here
5415          */
5416         pmc0 = ia64_get_pmc(0);
5417 
5418         task = GET_PMU_OWNER();
5419         ctx  = GET_PMU_CTX();
5420 
5421         /*
5422          * if we have some pending bits set
5423          * assumes : if any PMC0.bit[63-1] is set, then PMC0.fr = 1
5424          */
5425         if (PMC0_HAS_OVFL(pmc0) && task) {
5426                 /*
5427                  * we assume that pmc0.fr is always set here
5428                  */
5429 
5430                 /* sanity check */
5431                 if (!ctx) goto report_spurious1;
5432 
5433                 if (ctx->ctx_fl_system == 0 && (task->thread.flags & IA64_THREAD_PM_VALID) == 0) 
5434                         goto report_spurious2;
5435 
5436                 PROTECT_CTX_NOPRINT(ctx, flags);
5437 
5438                 pfm_overflow_handler(task, ctx, pmc0, regs);
5439 
5440                 UNPROTECT_CTX_NOPRINT(ctx, flags);
5441 
5442         } else {
5443                 pfm_stats[this_cpu].pfm_spurious_ovfl_intr_count++;
5444                 retval = -1;
5445         }
5446         /*
5447          * keep it unfrozen at all times
5448          */
5449         pfm_unfreeze_pmu();
5450 
5451         return retval;
5452 
5453 report_spurious1:
5454         printk(KERN_INFO "perfmon: spurious overflow interrupt on CPU%d: process %d has no PFM context\n",
5455                 this_cpu, task_pid_nr(task));
5456         pfm_unfreeze_pmu();
5457         return -1;
5458 report_spurious2:
5459         printk(KERN_INFO "perfmon: spurious overflow interrupt on CPU%d: process %d, invalid flag\n", 
5460                 this_cpu, 
5461                 task_pid_nr(task));
5462         pfm_unfreeze_pmu();
5463         return -1;
5464 }
5465 
5466 static irqreturn_t
5467 pfm_interrupt_handler(int irq, void *arg)
5468 {
5469         unsigned long start_cycles, total_cycles;
5470         unsigned long min, max;
5471         int this_cpu;
5472         int ret;
5473         struct pt_regs *regs = get_irq_regs();
5474 
5475         this_cpu = get_cpu();
5476         if (likely(!pfm_alt_intr_handler)) {
5477                 min = pfm_stats[this_cpu].pfm_ovfl_intr_cycles_min;
5478                 max = pfm_stats[this_cpu].pfm_ovfl_intr_cycles_max;
5479 
5480                 start_cycles = ia64_get_itc();
5481 
5482                 ret = pfm_do_interrupt_handler(arg, regs);
5483 
5484                 total_cycles = ia64_get_itc();
5485 
5486                 /*
5487                  * don't measure spurious interrupts
5488                  */
5489                 if (likely(ret == 0)) {
5490                         total_cycles -= start_cycles;
5491 
5492                         if (total_cycles < min) pfm_stats[this_cpu].pfm_ovfl_intr_cycles_min = total_cycles;
5493                         if (total_cycles > max) pfm_stats[this_cpu].pfm_ovfl_intr_cycles_max = total_cycles;
5494 
5495                         pfm_stats[this_cpu].pfm_ovfl_intr_cycles += total_cycles;
5496                 }
5497         }
5498         else {
5499                 (*pfm_alt_intr_handler->handler)(irq, arg, regs);
5500         }
5501 
5502         put_cpu();
5503         return IRQ_HANDLED;
5504 }
5505 
5506 /*
5507  * /proc/perfmon interface, for debug only
5508  */
5509 
5510 #define PFM_PROC_SHOW_HEADER    ((void *)(long)nr_cpu_ids+1)
5511 
5512 static void *
5513 pfm_proc_start(struct seq_file *m, loff_t *pos)
5514 {
5515         if (*pos == 0) {
5516                 return PFM_PROC_SHOW_HEADER;
5517         }
5518 
5519         while (*pos <= nr_cpu_ids) {
5520                 if (cpu_online(*pos - 1)) {
5521                         return (void *)*pos;
5522                 }
5523                 ++*pos;
5524         }
5525         return NULL;
5526 }
5527 
5528 static void *
5529 pfm_proc_next(struct seq_file *m, void *v, loff_t *pos)
5530 {
5531         ++*pos;
5532         return pfm_proc_start(m, pos);
5533 }
5534 
5535 static void
5536 pfm_proc_stop(struct seq_file *m, void *v)
5537 {
5538 }
5539 
5540 static void
5541 pfm_proc_show_header(struct seq_file *m)
5542 {
5543         struct list_head * pos;
5544         pfm_buffer_fmt_t * entry;
5545         unsigned long flags;
5546 
5547         seq_printf(m,
5548                 "perfmon version           : %u.%u\n"
5549                 "model                     : %s\n"
5550                 "fastctxsw                 : %s\n"
5551                 "expert mode               : %s\n"
5552                 "ovfl_mask                 : 0x%lx\n"
5553                 "PMU flags                 : 0x%x\n",
5554                 PFM_VERSION_MAJ, PFM_VERSION_MIN,
5555                 pmu_conf->pmu_name,
5556                 pfm_sysctl.fastctxsw > 0 ? "Yes": "No",
5557                 pfm_sysctl.expert_mode > 0 ? "Yes": "No",
5558                 pmu_conf->ovfl_val,
5559                 pmu_conf->flags);
5560 
5561         LOCK_PFS(flags);
5562 
5563         seq_printf(m,
5564                 "proc_sessions             : %u\n"
5565                 "sys_sessions              : %u\n"
5566                 "sys_use_dbregs            : %u\n"
5567                 "ptrace_use_dbregs         : %u\n",
5568                 pfm_sessions.pfs_task_sessions,
5569                 pfm_sessions.pfs_sys_sessions,
5570                 pfm_sessions.pfs_sys_use_dbregs,
5571                 pfm_sessions.pfs_ptrace_use_dbregs);
5572 
5573         UNLOCK_PFS(flags);
5574 
5575         spin_lock(&pfm_buffer_fmt_lock);
5576 
5577         list_for_each(pos, &pfm_buffer_fmt_list) {
5578                 entry = list_entry(pos, pfm_buffer_fmt_t, fmt_list);
5579                 seq_printf(m, "format                    : %16phD %s\n",
5580                            entry->fmt_uuid, entry->fmt_name);
5581         }
5582         spin_unlock(&pfm_buffer_fmt_lock);
5583 
5584 }
5585 
5586 static int
5587 pfm_proc_show(struct seq_file *m, void *v)
5588 {
5589         unsigned long psr;
5590         unsigned int i;
5591         int cpu;
5592 
5593         if (v == PFM_PROC_SHOW_HEADER) {
5594                 pfm_proc_show_header(m);
5595                 return 0;
5596         }
5597 
5598         /* show info for CPU (v - 1) */
5599 
5600         cpu = (long)v - 1;
5601         seq_printf(m,
5602                 "CPU%-2d overflow intrs      : %lu\n"
5603                 "CPU%-2d overflow cycles     : %lu\n"
5604                 "CPU%-2d overflow min        : %lu\n"
5605                 "CPU%-2d overflow max        : %lu\n"
5606                 "CPU%-2d smpl handler calls  : %lu\n"
5607                 "CPU%-2d smpl handler cycles : %lu\n"
5608                 "CPU%-2d spurious intrs      : %lu\n"
5609                 "CPU%-2d replay   intrs      : %lu\n"
5610                 "CPU%-2d syst_wide           : %d\n"
5611                 "CPU%-2d dcr_pp              : %d\n"
5612                 "CPU%-2d exclude idle        : %d\n"
5613                 "CPU%-2d owner               : %d\n"
5614                 "CPU%-2d context             : %p\n"
5615                 "CPU%-2d activations         : %lu\n",
5616                 cpu, pfm_stats[cpu].pfm_ovfl_intr_count,
5617                 cpu, pfm_stats[cpu].pfm_ovfl_intr_cycles,
5618                 cpu, pfm_stats[cpu].pfm_ovfl_intr_cycles_min,
5619                 cpu, pfm_stats[cpu].pfm_ovfl_intr_cycles_max,
5620                 cpu, pfm_stats[cpu].pfm_smpl_handler_calls,
5621                 cpu, pfm_stats[cpu].pfm_smpl_handler_cycles,
5622                 cpu, pfm_stats[cpu].pfm_spurious_ovfl_intr_count,
5623                 cpu, pfm_stats[cpu].pfm_replay_ovfl_intr_count,
5624                 cpu, pfm_get_cpu_data(pfm_syst_info, cpu) & PFM_CPUINFO_SYST_WIDE ? 1 : 0,
5625                 cpu, pfm_get_cpu_data(pfm_syst_info, cpu) & PFM_CPUINFO_DCR_PP ? 1 : 0,
5626                 cpu, pfm_get_cpu_data(pfm_syst_info, cpu) & PFM_CPUINFO_EXCL_IDLE ? 1 : 0,
5627                 cpu, pfm_get_cpu_data(pmu_owner, cpu) ? pfm_get_cpu_data(pmu_owner, cpu)->pid: -1,
5628                 cpu, pfm_get_cpu_data(pmu_ctx, cpu),
5629                 cpu, pfm_get_cpu_data(pmu_activation_number, cpu));
5630 
5631         if (num_online_cpus() == 1 && pfm_sysctl.debug > 0) {
5632 
5633                 psr = pfm_get_psr();
5634 
5635                 ia64_srlz_d();
5636 
5637                 seq_printf(m, 
5638                         "CPU%-2d psr                 : 0x%lx\n"
5639                         "CPU%-2d pmc0                : 0x%lx\n", 
5640                         cpu, psr,
5641                         cpu, ia64_get_pmc(0));
5642 
5643                 for (i=0; PMC_IS_LAST(i) == 0;  i++) {
5644                         if (PMC_IS_COUNTING(i) == 0) continue;
5645                         seq_printf(m, 
5646                                 "CPU%-2d pmc%u                : 0x%lx\n"
5647                                 "CPU%-2d pmd%u                : 0x%lx\n", 
5648                                 cpu, i, ia64_get_pmc(i),
5649                                 cpu, i, ia64_get_pmd(i));
5650                 }
5651         }
5652         return 0;
5653 }
5654 
5655 const struct seq_operations pfm_seq_ops = {
5656         .start =        pfm_proc_start,
5657         .next =         pfm_proc_next,
5658         .stop =         pfm_proc_stop,
5659         .show =         pfm_proc_show
5660 };
5661 
5662 /*
5663  * we come here as soon as local_cpu_data->pfm_syst_wide is set. this happens
5664  * during pfm_enable() hence before pfm_start(). We cannot assume monitoring
5665  * is active or inactive based on mode. We must rely on the value in
5666  * local_cpu_data->pfm_syst_info
5667  */
5668 void
5669 pfm_syst_wide_update_task(struct task_struct *task, unsigned long info, int is_ctxswin)
5670 {
5671         struct pt_regs *regs;
5672         unsigned long dcr;
5673         unsigned long dcr_pp;
5674 
5675         dcr_pp = info & PFM_CPUINFO_DCR_PP ? 1 : 0;
5676 
5677         /*
5678          * pid 0 is guaranteed to be the idle task. There is one such task with pid 0
5679          * on every CPU, so we can rely on the pid to identify the idle task.
5680          */
5681         if ((info & PFM_CPUINFO_EXCL_IDLE) == 0 || task->pid) {
5682                 regs = task_pt_regs(task);
5683                 ia64_psr(regs)->pp = is_ctxswin ? dcr_pp : 0;
5684                 return;
5685         }
5686         /*
5687          * if monitoring has started
5688          */
5689         if (dcr_pp) {
5690                 dcr = ia64_getreg(_IA64_REG_CR_DCR);
5691                 /*
5692                  * context switching in?
5693                  */
5694                 if (is_ctxswin) {
5695                         /* mask monitoring for the idle task */
5696                         ia64_setreg(_IA64_REG_CR_DCR, dcr & ~IA64_DCR_PP);
5697                         pfm_clear_psr_pp();
5698                         ia64_srlz_i();
5699                         return;
5700                 }
5701                 /*
5702                  * context switching out
5703                  * restore monitoring for next task
5704                  *
5705                  * Due to inlining this odd if-then-else construction generates
5706                  * better code.
5707                  */
5708                 ia64_setreg(_IA64_REG_CR_DCR, dcr |IA64_DCR_PP);
5709                 pfm_set_psr_pp();
5710                 ia64_srlz_i();
5711         }
5712 }
5713 
5714 #ifdef CONFIG_SMP
5715 
5716 static void
5717 pfm_force_cleanup(pfm_context_t *ctx, struct pt_regs *regs)
5718 {
5719         struct task_struct *task = ctx->ctx_task;
5720 
5721         ia64_psr(regs)->up = 0;
5722         ia64_psr(regs)->sp = 1;
5723 
5724         if (GET_PMU_OWNER() == task) {
5725                 DPRINT(("cleared ownership for [%d]\n",
5726                                         task_pid_nr(ctx->ctx_task)));
5727                 SET_PMU_OWNER(NULL, NULL);
5728         }
5729 
5730         /*
5731          * disconnect the task from the context and vice-versa
5732          */
5733         PFM_SET_WORK_PENDING(task, 0);
5734 
5735         task->thread.pfm_context  = NULL;
5736         task->thread.flags       &= ~IA64_THREAD_PM_VALID;
5737 
5738         DPRINT(("force cleanup for [%d]\n",  task_pid_nr(task)));
5739 }
5740 
5741 
5742 /*
5743  * in 2.6, interrupts are masked when we come here and the runqueue lock is held
5744  */
5745 void
5746 pfm_save_regs(struct task_struct *task)
5747 {
5748         pfm_context_t *ctx;
5749         unsigned long flags;
5750         u64 psr;
5751 
5752 
5753         ctx = PFM_GET_CTX(task);
5754         if (ctx == NULL) return;
5755 
5756         /*
5757          * we always come here with interrupts ALREADY disabled by
5758          * the scheduler. So we simply need to protect against concurrent
5759          * access, not CPU concurrency.
5760          */
5761         flags = pfm_protect_ctx_ctxsw(ctx);
5762 
5763         if (ctx->ctx_state == PFM_CTX_ZOMBIE) {
5764                 struct pt_regs *regs = task_pt_regs(task);
5765 
5766                 pfm_clear_psr_up();
5767 
5768                 pfm_force_cleanup(ctx, regs);
5769 
5770                 BUG_ON(ctx->ctx_smpl_hdr);
5771 
5772                 pfm_unprotect_ctx_ctxsw(ctx, flags);
5773 
5774                 pfm_context_free(ctx);
5775                 return;
5776         }
5777 
5778         /*
5779          * save current PSR: needed because we modify it
5780          */
5781         ia64_srlz_d();
5782         psr = pfm_get_psr();
5783 
5784         BUG_ON(psr & (IA64_PSR_I));
5785 
5786         /*
5787          * stop monitoring:
5788          * This is the last instruction which may generate an overflow
5789          *
5790          * We do not need to set psr.sp because, it is irrelevant in kernel.
5791          * It will be restored from ipsr when going back to user level
5792          */
5793         pfm_clear_psr_up();
5794 
5795         /*
5796          * keep a copy of psr.up (for reload)
5797          */
5798         ctx->ctx_saved_psr_up = psr & IA64_PSR_UP;
5799 
5800         /*
5801          * release ownership of this PMU.
5802          * PM interrupts are masked, so nothing
5803          * can happen.
5804          */
5805         SET_PMU_OWNER(NULL, NULL);
5806 
5807         /*
5808          * we systematically save the PMD as we have no
5809          * guarantee we will be schedule at that same
5810          * CPU again.
5811          */
5812         pfm_save_pmds(ctx->th_pmds, ctx->ctx_used_pmds[0]);
5813 
5814         /*
5815          * save pmc0 ia64_srlz_d() done in pfm_save_pmds()
5816          * we will need it on the restore path to check
5817          * for pending overflow.
5818          */
5819         ctx->th_pmcs[0] = ia64_get_pmc(0);
5820 
5821         /*
5822          * unfreeze PMU if had pending overflows
5823          */
5824         if (ctx->th_pmcs[0] & ~0x1UL) pfm_unfreeze_pmu();
5825 
5826         /*
5827          * finally, allow context access.
5828          * interrupts will still be masked after this call.
5829          */
5830         pfm_unprotect_ctx_ctxsw(ctx, flags);
5831 }
5832 
5833 #else /* !CONFIG_SMP */
5834 void
5835 pfm_save_regs(struct task_struct *task)
5836 {
5837         pfm_context_t *ctx;
5838         u64 psr;
5839 
5840         ctx = PFM_GET_CTX(task);
5841         if (ctx == NULL) return;
5842 
5843         /*
5844          * save current PSR: needed because we modify it
5845          */
5846         psr = pfm_get_psr();
5847 
5848         BUG_ON(psr & (IA64_PSR_I));
5849 
5850         /*
5851          * stop monitoring:
5852          * This is the last instruction which may generate an overflow
5853          *
5854          * We do not need to set psr.sp because, it is irrelevant in kernel.
5855          * It will be restored from ipsr when going back to user level
5856          */
5857         pfm_clear_psr_up();
5858 
5859         /*
5860          * keep a copy of psr.up (for reload)
5861          */
5862         ctx->ctx_saved_psr_up = psr & IA64_PSR_UP;
5863 }
5864 
5865 static void
5866 pfm_lazy_save_regs (struct task_struct *task)
5867 {
5868         pfm_context_t *ctx;
5869         unsigned long flags;
5870 
5871         { u64 psr  = pfm_get_psr();
5872           BUG_ON(psr & IA64_PSR_UP);
5873         }
5874 
5875         ctx = PFM_GET_CTX(task);
5876 
5877         /*
5878          * we need to mask PMU overflow here to
5879          * make sure that we maintain pmc0 until
5880          * we save it. overflow interrupts are
5881          * treated as spurious if there is no
5882          * owner.
5883          *
5884          * XXX: I don't think this is necessary
5885          */
5886         PROTECT_CTX(ctx,flags);
5887 
5888         /*
5889          * release ownership of this PMU.
5890          * must be done before we save the registers.
5891          *
5892          * after this call any PMU interrupt is treated
5893          * as spurious.
5894          */
5895         SET_PMU_OWNER(NULL, NULL);
5896 
5897         /*
5898          * save all the pmds we use
5899          */
5900         pfm_save_pmds(ctx->th_pmds, ctx->ctx_used_pmds[0]);
5901 
5902         /*
5903          * save pmc0 ia64_srlz_d() done in pfm_save_pmds()
5904          * it is needed to check for pended overflow
5905          * on the restore path
5906          */
5907         ctx->th_pmcs[0] = ia64_get_pmc(0);
5908 
5909         /*
5910          * unfreeze PMU if had pending overflows
5911          */
5912         if (ctx->th_pmcs[0] & ~0x1UL) pfm_unfreeze_pmu();
5913 
5914         /*
5915          * now get can unmask PMU interrupts, they will
5916          * be treated as purely spurious and we will not
5917          * lose any information
5918          */
5919         UNPROTECT_CTX(ctx,flags);
5920 }
5921 #endif /* CONFIG_SMP */
5922 
5923 #ifdef CONFIG_SMP
5924 /*
5925  * in 2.6, interrupts are masked when we come here and the runqueue lock is held
5926  */
5927 void
5928 pfm_load_regs (struct task_struct *task)
5929 {
5930         pfm_context_t *ctx;
5931         unsigned long pmc_mask = 0UL, pmd_mask = 0UL;
5932         unsigned long flags;
5933         u64 psr, psr_up;
5934         int need_irq_resend;
5935 
5936         ctx = PFM_GET_CTX(task);
5937         if (unlikely(ctx == NULL)) return;
5938 
5939         BUG_ON(GET_PMU_OWNER());
5940 
5941         /*
5942          * possible on unload
5943          */
5944         if (unlikely((task->thread.flags & IA64_THREAD_PM_VALID) == 0)) return;
5945 
5946         /*
5947          * we always come here with interrupts ALREADY disabled by
5948          * the scheduler. So we simply need to protect against concurrent
5949          * access, not CPU concurrency.
5950          */
5951         flags = pfm_protect_ctx_ctxsw(ctx);
5952         psr   = pfm_get_psr();
5953 
5954         need_irq_resend = pmu_conf->flags & PFM_PMU_IRQ_RESEND;
5955 
5956         BUG_ON(psr & (IA64_PSR_UP|IA64_PSR_PP));
5957         BUG_ON(psr & IA64_PSR_I);
5958 
5959         if (unlikely(ctx->ctx_state == PFM_CTX_ZOMBIE)) {
5960                 struct pt_regs *regs = task_pt_regs(task);
5961 
5962                 BUG_ON(ctx->ctx_smpl_hdr);
5963 
5964                 pfm_force_cleanup(ctx, regs);
5965 
5966                 pfm_unprotect_ctx_ctxsw(ctx, flags);
5967 
5968                 /*
5969                  * this one (kmalloc'ed) is fine with interrupts disabled
5970                  */
5971                 pfm_context_free(ctx);
5972 
5973                 return;
5974         }
5975 
5976         /*
5977          * we restore ALL the debug registers to avoid picking up
5978          * stale state.
5979          */
5980         if (ctx->ctx_fl_using_dbreg) {
5981                 pfm_restore_ibrs(ctx->ctx_ibrs, pmu_conf->num_ibrs);
5982                 pfm_restore_dbrs(ctx->ctx_dbrs, pmu_conf->num_dbrs);
5983         }
5984         /*
5985          * retrieve saved psr.up
5986          */
5987         psr_up = ctx->ctx_saved_psr_up;
5988 
5989         /*
5990          * if we were the last user of the PMU on that CPU,
5991          * then nothing to do except restore psr
5992          */
5993         if (GET_LAST_CPU(ctx) == smp_processor_id() && ctx->ctx_last_activation == GET_ACTIVATION()) {
5994 
5995                 /*
5996                  * retrieve partial reload masks (due to user modifications)
5997                  */
5998                 pmc_mask = ctx->ctx_reload_pmcs[0];
5999                 pmd_mask = ctx->ctx_reload_pmds[0];
6000 
6001         } else {
6002                 /*
6003                  * To avoid leaking information to the user level when psr.sp=0,
6004                  * we must reload ALL implemented pmds (even the ones we don't use).
6005                  * In the kernel we only allow PFM_READ_PMDS on registers which
6006                  * we initialized or requested (sampling) so there is no risk there.
6007                  */
6008                 pmd_mask = pfm_sysctl.fastctxsw ?  ctx->ctx_used_pmds[0] : ctx->ctx_all_pmds[0];
6009 
6010                 /*
6011                  * ALL accessible PMCs are systematically reloaded, unused registers
6012                  * get their default (from pfm_reset_pmu_state()) values to avoid picking
6013                  * up stale configuration.
6014                  *
6015                  * PMC0 is never in the mask. It is always restored separately.
6016                  */
6017                 pmc_mask = ctx->ctx_all_pmcs[0];
6018         }
6019         /*
6020          * when context is MASKED, we will restore PMC with plm=0
6021          * and PMD with stale information, but that's ok, nothing
6022          * will be captured.
6023          *
6024          * XXX: optimize here
6025          */
6026         if (pmd_mask) pfm_restore_pmds(ctx->th_pmds, pmd_mask);
6027         if (pmc_mask) pfm_restore_pmcs(ctx->th_pmcs, pmc_mask);
6028 
6029         /*
6030          * check for pending overflow at the time the state
6031          * was saved.
6032          */
6033         if (unlikely(PMC0_HAS_OVFL(ctx->th_pmcs[0]))) {
6034                 /*
6035                  * reload pmc0 with the overflow information
6036                  * On McKinley PMU, this will trigger a PMU interrupt
6037                  */
6038                 ia64_set_pmc(0, ctx->th_pmcs[0]);
6039                 ia64_srlz_d();
6040                 ctx->th_pmcs[0] = 0UL;
6041 
6042                 /*
6043                  * will replay the PMU interrupt
6044                  */
6045                 if (need_irq_resend) ia64_resend_irq(IA64_PERFMON_VECTOR);
6046 
6047                 pfm_stats[smp_processor_id()].pfm_replay_ovfl_intr_count++;
6048         }
6049 
6050         /*
6051          * we just did a reload, so we reset the partial reload fields
6052          */
6053         ctx->ctx_reload_pmcs[0] = 0UL;
6054         ctx->ctx_reload_pmds[0] = 0UL;
6055 
6056         SET_LAST_CPU(ctx, smp_processor_id());
6057 
6058         /*
6059          * dump activation value for this PMU
6060          */
6061         INC_ACTIVATION();
6062         /*
6063          * record current activation for this context
6064          */
6065         SET_ACTIVATION(ctx);
6066 
6067         /*
6068          * establish new ownership. 
6069          */
6070         SET_PMU_OWNER(task, ctx);
6071 
6072         /*
6073          * restore the psr.up bit. measurement
6074          * is active again.
6075          * no PMU interrupt can happen at this point
6076          * because we still have interrupts disabled.
6077          */
6078         if (likely(psr_up)) pfm_set_psr_up();
6079 
6080         /*
6081          * allow concurrent access to context
6082          */
6083         pfm_unprotect_ctx_ctxsw(ctx, flags);
6084 }
6085 #else /*  !CONFIG_SMP */
6086 /*
6087  * reload PMU state for UP kernels
6088  * in 2.5 we come here with interrupts disabled
6089  */
6090 void
6091 pfm_load_regs (struct task_struct *task)
6092 {
6093         pfm_context_t *ctx;
6094         struct task_struct *owner;
6095         unsigned long pmd_mask, pmc_mask;
6096         u64 psr, psr_up;
6097         int need_irq_resend;
6098 
6099         owner = GET_PMU_OWNER();
6100         ctx   = PFM_GET_CTX(task);
6101         psr   = pfm_get_psr();
6102 
6103         BUG_ON(psr & (IA64_PSR_UP|IA64_PSR_PP));
6104         BUG_ON(psr & IA64_PSR_I);
6105 
6106         /*
6107          * we restore ALL the debug registers to avoid picking up
6108          * stale state.
6109          *
6110          * This must be done even when the task is still the owner
6111          * as the registers may have been modified via ptrace()
6112          * (not perfmon) by the previous task.
6113          */
6114         if (ctx->ctx_fl_using_dbreg) {
6115                 pfm_restore_ibrs(ctx->ctx_ibrs, pmu_conf->num_ibrs);
6116                 pfm_restore_dbrs(ctx->ctx_dbrs, pmu_conf->num_dbrs);
6117         }
6118 
6119         /*
6120          * retrieved saved psr.up
6121          */
6122         psr_up = ctx->ctx_saved_psr_up;
6123         need_irq_resend = pmu_conf->flags & PFM_PMU_IRQ_RESEND;
6124 
6125         /*
6126          * short path, our state is still there, just
6127          * need to restore psr and we go
6128          *
6129          * we do not touch either PMC nor PMD. the psr is not touched
6130          * by the overflow_handler. So we are safe w.r.t. to interrupt
6131          * concurrency even without interrupt masking.
6132          */
6133         if (likely(owner == task)) {
6134                 if (likely(psr_up)) pfm_set_psr_up();
6135                 return;
6136         }
6137 
6138         /*
6139          * someone else is still using the PMU, first push it out and
6140          * then we'll be able to install our stuff !
6141          *
6142          * Upon return, there will be no owner for the current PMU
6143          */
6144         if (owner) pfm_lazy_save_regs(owner);
6145 
6146         /*
6147          * To avoid leaking information to the user level when psr.sp=0,
6148          * we must reload ALL implemented pmds (even the ones we don't use).
6149          * In the kernel we only allow PFM_READ_PMDS on registers which
6150          * we initialized or requested (sampling) so there is no risk there.
6151          */
6152         pmd_mask = pfm_sysctl.fastctxsw ?  ctx->ctx_used_pmds[0] : ctx->ctx_all_pmds[0];
6153 
6154         /*
6155          * ALL accessible PMCs are systematically reloaded, unused registers
6156          * get their default (from pfm_reset_pmu_state()) values to avoid picking
6157          * up stale configuration.
6158          *
6159          * PMC0 is never in the mask. It is always restored separately
6160          */
6161         pmc_mask = ctx->ctx_all_pmcs[0];
6162 
6163         pfm_restore_pmds(ctx->th_pmds, pmd_mask);
6164         pfm_restore_pmcs(ctx->th_pmcs, pmc_mask);
6165 
6166         /*
6167          * check for pending overflow at the time the state
6168          * was saved.
6169          */
6170         if (unlikely(PMC0_HAS_OVFL(ctx->th_pmcs[0]))) {
6171                 /*
6172                  * reload pmc0 with the overflow information
6173                  * On McKinley PMU, this will trigger a PMU interrupt
6174                  */
6175                 ia64_set_pmc(0, ctx->th_pmcs[0]);
6176                 ia64_srlz_d();
6177 
6178                 ctx->th_pmcs[0] = 0UL;
6179 
6180                 /*
6181                  * will replay the PMU interrupt
6182                  */
6183                 if (need_irq_resend) ia64_resend_irq(IA64_PERFMON_VECTOR);
6184 
6185                 pfm_stats[smp_processor_id()].pfm_replay_ovfl_intr_count++;
6186         }
6187 
6188         /*
6189          * establish new ownership. 
6190          */
6191         SET_PMU_OWNER(task, ctx);
6192 
6193         /*
6194          * restore the psr.up bit. measurement
6195          * is active again.
6196          * no PMU interrupt can happen at this point
6197          * because we still have interrupts disabled.
6198          */
6199         if (likely(psr_up)) pfm_set_psr_up();
6200 }
6201 #endif /* CONFIG_SMP */
6202 
6203 /*
6204  * this function assumes monitoring is stopped
6205  */
6206 static void
6207 pfm_flush_pmds(struct task_struct *task, pfm_context_t *ctx)
6208 {
6209         u64 pmc0;
6210         unsigned long mask2, val, pmd_val, ovfl_val;
6211         int i, can_access_pmu = 0;
6212         int is_self;
6213 
6214         /*
6215          * is the caller the task being monitored (or which initiated the
6216          * session for system wide measurements)
6217          */
6218         is_self = ctx->ctx_task == task ? 1 : 0;
6219 
6220         /*
6221          * can access PMU is task is the owner of the PMU state on the current CPU
6222          * or if we are running on the CPU bound to the context in system-wide mode
6223          * (that is not necessarily the task the context is attached to in this mode).
6224          * In system-wide we always have can_access_pmu true because a task running on an
6225          * invalid processor is flagged earlier in the call stack (see pfm_stop).
6226          */
6227         can_access_pmu = (GET_PMU_OWNER() == task) || (ctx->ctx_fl_system && ctx->ctx_cpu == smp_processor_id());
6228         if (can_access_pmu) {
6229                 /*
6230                  * Mark the PMU as not owned
6231                  * This will cause the interrupt handler to do nothing in case an overflow
6232                  * interrupt was in-flight
6233                  * This also guarantees that pmc0 will contain the final state
6234                  * It virtually gives us full control on overflow processing from that point
6235                  * on.
6236                  */
6237                 SET_PMU_OWNER(NULL, NULL);
6238                 DPRINT(("releasing ownership\n"));
6239 
6240                 /*
6241                  * read current overflow status:
6242                  *
6243                  * we are guaranteed to read the final stable state
6244                  */
6245                 ia64_srlz_d();
6246                 pmc0 = ia64_get_pmc(0); /* slow */
6247 
6248                 /*
6249                  * reset freeze bit, overflow status information destroyed
6250                  */
6251                 pfm_unfreeze_pmu();
6252         } else {
6253                 pmc0 = ctx->th_pmcs[0];
6254                 /*
6255                  * clear whatever overflow status bits there were
6256                  */
6257                 ctx->th_pmcs[0] = 0;
6258         }
6259         ovfl_val = pmu_conf->ovfl_val;
6260         /*
6261          * we save all the used pmds
6262          * we take care of overflows for counting PMDs
6263          *
6264          * XXX: sampling situation is not taken into account here
6265          */
6266         mask2 = ctx->ctx_used_pmds[0];
6267 
6268         DPRINT(("is_self=%d ovfl_val=0x%lx mask2=0x%lx\n", is_self, ovfl_val, mask2));
6269 
6270         for (i = 0; mask2; i++, mask2>>=1) {
6271 
6272                 /* skip non used pmds */
6273                 if ((mask2 & 0x1) == 0) continue;
6274 
6275                 /*
6276                  * can access PMU always true in system wide mode
6277                  */
6278                 val = pmd_val = can_access_pmu ? ia64_get_pmd(i) : ctx->th_pmds[i];
6279 
6280                 if (PMD_IS_COUNTING(i)) {
6281                         DPRINT(("[%d] pmd[%d] ctx_pmd=0x%lx hw_pmd=0x%lx\n",
6282                                 task_pid_nr(task),
6283                                 i,
6284                                 ctx->ctx_pmds[i].val,
6285                                 val & ovfl_val));
6286 
6287                         /*
6288                          * we rebuild the full 64 bit value of the counter
6289                          */
6290                         val = ctx->ctx_pmds[i].val + (val & ovfl_val);
6291 
6292                         /*
6293                          * now everything is in ctx_pmds[] and we need
6294                          * to clear the saved context from save_regs() such that
6295                          * pfm_read_pmds() gets the correct value
6296                          */
6297                         pmd_val = 0UL;
6298 
6299                         /*
6300                          * take care of overflow inline
6301                          */
6302                         if (pmc0 & (1UL << i)) {
6303                                 val += 1 + ovfl_val;
6304                                 DPRINT(("[%d] pmd[%d] overflowed\n", task_pid_nr(task), i));
6305                         }
6306                 }
6307 
6308                 DPRINT(("[%d] ctx_pmd[%d]=0x%lx  pmd_val=0x%lx\n", task_pid_nr(task), i, val, pmd_val));
6309 
6310                 if (is_self) ctx->th_pmds[i] = pmd_val;
6311 
6312                 ctx->ctx_pmds[i].val = val;
6313         }
6314 }
6315 
6316 static struct irqaction perfmon_irqaction = {
6317         .handler = pfm_interrupt_handler,
6318         .name    = "perfmon"
6319 };
6320 
6321 static void
6322 pfm_alt_save_pmu_state(void *data)
6323 {
6324         struct pt_regs *regs;
6325 
6326         regs = task_pt_regs(current);
6327 
6328         DPRINT(("called\n"));
6329 
6330         /*
6331          * should not be necessary but
6332          * let's take not risk
6333          */
6334         pfm_clear_psr_up();
6335         pfm_clear_psr_pp();
6336         ia64_psr(regs)->pp = 0;
6337 
6338         /*
6339          * This call is required
6340          * May cause a spurious interrupt on some processors
6341          */
6342         pfm_freeze_pmu();
6343 
6344         ia64_srlz_d();
6345 }
6346 
6347 void
6348 pfm_alt_restore_pmu_state(void *data)
6349 {
6350         struct pt_regs *regs;
6351 
6352         regs = task_pt_regs(current);
6353 
6354         DPRINT(("called\n"));
6355 
6356         /*
6357          * put PMU back in state expected
6358          * by perfmon
6359          */
6360         pfm_clear_psr_up();
6361         pfm_clear_psr_pp();
6362         ia64_psr(regs)->pp = 0;
6363 
6364         /*
6365          * perfmon runs with PMU unfrozen at all times
6366          */
6367         pfm_unfreeze_pmu();
6368 
6369         ia64_srlz_d();
6370 }
6371 
6372 int
6373 pfm_install_alt_pmu_interrupt(pfm_intr_handler_desc_t *hdl)
6374 {
6375         int ret, i;
6376         int reserve_cpu;
6377 
6378         /* some sanity checks */
6379         if (hdl == NULL || hdl->handler == NULL) return -EINVAL;
6380 
6381         /* do the easy test first */
6382         if (pfm_alt_intr_handler) return -EBUSY;
6383 
6384         /* one at a time in the install or remove, just fail the others */
6385         if (!spin_trylock(&pfm_alt_install_check)) {
6386                 return -EBUSY;
6387         }
6388 
6389         /* reserve our session */
6390         for_each_online_cpu(reserve_cpu) {
6391                 ret = pfm_reserve_session(NULL, 1, reserve_cpu);
6392                 if (ret) goto cleanup_reserve;
6393         }
6394 
6395         /* save the current system wide pmu states */
6396         on_each_cpu(pfm_alt_save_pmu_state, NULL, 1);
6397 
6398         /* officially change to the alternate interrupt handler */
6399         pfm_alt_intr_handler = hdl;
6400 
6401         spin_unlock(&pfm_alt_install_check);
6402 
6403         return 0;
6404 
6405 cleanup_reserve:
6406         for_each_online_cpu(i) {
6407                 /* don't unreserve more than we reserved */
6408                 if (i >= reserve_cpu) break;
6409 
6410                 pfm_unreserve_session(NULL, 1, i);
6411         }
6412 
6413         spin_unlock(&pfm_alt_install_check);
6414 
6415         return ret;
6416 }
6417 EXPORT_SYMBOL_GPL(pfm_install_alt_pmu_interrupt);
6418 
6419 int
6420 pfm_remove_alt_pmu_interrupt(pfm_intr_handler_desc_t *hdl)
6421 {
6422         int i;
6423 
6424         if (hdl == NULL) return -EINVAL;
6425 
6426         /* cannot remove someone else's handler! */
6427         if (pfm_alt_intr_handler != hdl) return -EINVAL;
6428 
6429         /* one at a time in the install or remove, just fail the others */
6430         if (!spin_trylock(&pfm_alt_install_check)) {
6431                 return -EBUSY;
6432         }
6433 
6434         pfm_alt_intr_handler = NULL;
6435 
6436         on_each_cpu(pfm_alt_restore_pmu_state, NULL, 1);
6437 
6438         for_each_online_cpu(i) {
6439                 pfm_unreserve_session(NULL, 1, i);
6440         }
6441 
6442         spin_unlock(&pfm_alt_install_check);
6443 
6444         return 0;
6445 }
6446 EXPORT_SYMBOL_GPL(pfm_remove_alt_pmu_interrupt);
6447 
6448 /*
6449  * perfmon initialization routine, called from the initcall() table
6450  */
6451 static int init_pfm_fs(void);
6452 
6453 static int __init
6454 pfm_probe_pmu(void)
6455 {
6456         pmu_config_t **p;
6457         int family;
6458 
6459         family = local_cpu_data->family;
6460         p      = pmu_confs;
6461 
6462         while(*p) {
6463                 if ((*p)->probe) {
6464                         if ((*p)->probe() == 0) goto found;
6465                 } else if ((*p)->pmu_family == family || (*p)->pmu_family == 0xff) {
6466                         goto found;
6467                 }
6468                 p++;
6469         }
6470         return -1;
6471 found:
6472         pmu_conf = *p;
6473         return 0;
6474 }
6475 
6476 int __init
6477 pfm_init(void)
6478 {
6479         unsigned int n, n_counters, i;
6480 
6481         printk("perfmon: version %u.%u IRQ %u\n",
6482                 PFM_VERSION_MAJ,
6483                 PFM_VERSION_MIN,
6484                 IA64_PERFMON_VECTOR);
6485 
6486         if (pfm_probe_pmu()) {
6487                 printk(KERN_INFO "perfmon: disabled, there is no support for processor family %d\n", 
6488                                 local_cpu_data->family);
6489                 return -ENODEV;
6490         }
6491 
6492         /*
6493          * compute the number of implemented PMD/PMC from the
6494          * description tables
6495          */
6496         n = 0;
6497         for (i=0; PMC_IS_LAST(i) == 0;  i++) {
6498                 if (PMC_IS_IMPL(i) == 0) continue;
6499                 pmu_conf->impl_pmcs[i>>6] |= 1UL << (i&63);
6500                 n++;
6501         }
6502         pmu_conf->num_pmcs = n;
6503 
6504         n = 0; n_counters = 0;
6505         for (i=0; PMD_IS_LAST(i) == 0;  i++) {
6506                 if (PMD_IS_IMPL(i) == 0) continue;
6507                 pmu_conf->impl_pmds[i>>6] |= 1UL << (i&63);
6508                 n++;
6509                 if (PMD_IS_COUNTING(i)) n_counters++;
6510         }
6511         pmu_conf->num_pmds      = n;
6512         pmu_conf->num_counters  = n_counters;
6513 
6514         /*
6515          * sanity checks on the number of debug registers
6516          */
6517         if (pmu_conf->use_rr_dbregs) {
6518                 if (pmu_conf->num_ibrs > IA64_NUM_DBG_REGS) {
6519                         printk(KERN_INFO "perfmon: unsupported number of code debug registers (%u)\n", pmu_conf->num_ibrs);
6520                         pmu_conf = NULL;
6521                         return -1;
6522                 }
6523                 if (pmu_conf->num_dbrs > IA64_NUM_DBG_REGS) {
6524                         printk(KERN_INFO "perfmon: unsupported number of data debug registers (%u)\n", pmu_conf->num_ibrs);
6525                         pmu_conf = NULL;
6526                         return -1;
6527                 }
6528         }
6529 
6530         printk("perfmon: %s PMU detected, %u PMCs, %u PMDs, %u counters (%lu bits)\n",
6531                pmu_conf->pmu_name,
6532                pmu_conf->num_pmcs,
6533                pmu_conf->num_pmds,
6534                pmu_conf->num_counters,
6535                ffz(pmu_conf->ovfl_val));
6536 
6537         /* sanity check */
6538         if (pmu_conf->num_pmds >= PFM_NUM_PMD_REGS || pmu_conf->num_pmcs >= PFM_NUM_PMC_REGS) {
6539                 printk(KERN_ERR "perfmon: not enough pmc/pmd, perfmon disabled\n");
6540                 pmu_conf = NULL;
6541                 return -1;
6542         }
6543 
6544         /*
6545          * create /proc/perfmon (mostly for debugging purposes)
6546          */
6547         perfmon_dir = proc_create_seq("perfmon", S_IRUGO, NULL, &pfm_seq_ops);
6548         if (perfmon_dir == NULL) {
6549                 printk(KERN_ERR "perfmon: cannot create /proc entry, perfmon disabled\n");
6550                 pmu_conf = NULL;
6551                 return -1;
6552         }
6553 
6554         /*
6555          * create /proc/sys/kernel/perfmon (for debugging purposes)
6556          */
6557         pfm_sysctl_header = register_sysctl_table(pfm_sysctl_root);
6558 
6559         /*
6560          * initialize all our spinlocks
6561          */
6562         spin_lock_init(&pfm_sessions.pfs_lock);
6563         spin_lock_init(&pfm_buffer_fmt_lock);
6564 
6565         init_pfm_fs();
6566 
6567         for(i=0; i < NR_CPUS; i++) pfm_stats[i].pfm_ovfl_intr_cycles_min = ~0UL;
6568 
6569         return 0;
6570 }
6571 
6572 __initcall(pfm_init);
6573 
6574 /*
6575  * this function is called before pfm_init()
6576  */
6577 void
6578 pfm_init_percpu (void)
6579 {
6580         static int first_time=1;
6581         /*
6582          * make sure no measurement is active
6583          * (may inherit programmed PMCs from EFI).
6584          */
6585         pfm_clear_psr_pp();
6586         pfm_clear_psr_up();
6587 
6588         /*
6589          * we run with the PMU not frozen at all times
6590          */
6591         pfm_unfreeze_pmu();
6592 
6593         if (first_time) {
6594                 register_percpu_irq(IA64_PERFMON_VECTOR, &perfmon_irqaction);
6595                 first_time=0;
6596         }
6597 
6598         ia64_setreg(_IA64_REG_CR_PMV, IA64_PERFMON_VECTOR);
6599         ia64_srlz_d();
6600 }
6601 
6602 /*
6603  * used for debug purposes only
6604  */
6605 void
6606 dump_pmu_state(const char *from)
6607 {
6608         struct task_struct *task;
6609         struct pt_regs *regs;
6610         pfm_context_t *ctx;
6611         unsigned long psr, dcr, info, flags;
6612         int i, this_cpu;
6613 
6614         local_irq_save(flags);
6615 
6616         this_cpu = smp_processor_id();
6617         regs     = task_pt_regs(current);
6618         info     = PFM_CPUINFO_GET();
6619         dcr      = ia64_getreg(_IA64_REG_CR_DCR);
6620 
6621         if (info == 0 && ia64_psr(regs)->pp == 0 && (dcr & IA64_DCR_PP) == 0) {
6622                 local_irq_restore(flags);
6623                 return;
6624         }
6625 
6626         printk("CPU%d from %s() current [%d] iip=0x%lx %s\n", 
6627                 this_cpu, 
6628                 from, 
6629                 task_pid_nr(current),
6630                 regs->cr_iip,
6631                 current->comm);
6632 
6633         task = GET_PMU_OWNER();
6634         ctx  = GET_PMU_CTX();
6635 
6636         printk("->CPU%d owner [%d] ctx=%p\n", this_cpu, task ? task_pid_nr(task) : -1, ctx);
6637 
6638         psr = pfm_get_psr();
6639 
6640         printk("->CPU%d pmc0=0x%lx psr.pp=%d psr.up=%d dcr.pp=%d syst_info=0x%lx user_psr.up=%d user_psr.pp=%d\n", 
6641                 this_cpu,
6642                 ia64_get_pmc(0),
6643                 psr & IA64_PSR_PP ? 1 : 0,
6644                 psr & IA64_PSR_UP ? 1 : 0,
6645                 dcr & IA64_DCR_PP ? 1 : 0,
6646                 info,
6647                 ia64_psr(regs)->up,
6648                 ia64_psr(regs)->pp);
6649 
6650         ia64_psr(regs)->up = 0;
6651         ia64_psr(regs)->pp = 0;
6652 
6653         for (i=1; PMC_IS_LAST(i) == 0; i++) {
6654                 if (PMC_IS_IMPL(i) == 0) continue;
6655                 printk("->CPU%d pmc[%d]=0x%lx thread_pmc[%d]=0x%lx\n", this_cpu, i, ia64_get_pmc(i), i, ctx->th_pmcs[i]);
6656         }
6657 
6658         for (i=1; PMD_IS_LAST(i) == 0; i++) {
6659                 if (PMD_IS_IMPL(i) == 0) continue;
6660                 printk("->CPU%d pmd[%d]=0x%lx thread_pmd[%d]=0x%lx\n", this_cpu, i, ia64_get_pmd(i), i, ctx->th_pmds[i]);
6661         }
6662 
6663         if (ctx) {
6664                 printk("->CPU%d ctx_state=%d vaddr=%p addr=%p fd=%d ctx_task=[%d] saved_psr_up=0x%lx\n",
6665                                 this_cpu,
6666                                 ctx->ctx_state,
6667                                 ctx->ctx_smpl_vaddr,
6668                                 ctx->ctx_smpl_hdr,
6669                                 ctx->ctx_msgq_head,
6670                                 ctx->ctx_msgq_tail,
6671                                 ctx->ctx_saved_psr_up);
6672         }
6673         local_irq_restore(flags);
6674 }
6675 
6676 /*
6677  * called from process.c:copy_thread(). task is new child.
6678  */
6679 void
6680 pfm_inherit(struct task_struct *task, struct pt_regs *regs)
6681 {
6682         struct thread_struct *thread;
6683 
6684         DPRINT(("perfmon: pfm_inherit clearing state for [%d]\n", task_pid_nr(task)));
6685 
6686         thread = &task->thread;
6687 
6688         /*
6689          * cut links inherited from parent (current)
6690          */
6691         thread->pfm_context = NULL;
6692 
6693         PFM_SET_WORK_PENDING(task, 0);
6694 
6695         /*
6696          * the psr bits are already set properly in copy_threads()
6697          */
6698 }
6699 #else  /* !CONFIG_PERFMON */
6700 asmlinkage long
6701 sys_perfmonctl (int fd, int cmd, void *arg, int count)
6702 {
6703         return -ENOSYS;
6704 }
6705 #endif /* CONFIG_PERFMON */
/* [<][>][^][v][top][bottom][index][help] */
root/arch/ia64/kernel/perfmon.c

DEFINITIONS
