kernel/trace/trace.h

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
top_trace_array
trace_get_context_bit
trace_test_and_set_recursion
trace_clear_recursion
trace_buffer_iter
__trace_stack
ftrace_init_trace_array
ftrace_hash_empty
ftrace_graph_graph_time_control
ftrace_graph_addr
ftrace_graph_addr_finish
ftrace_graph_notrace_addr
ftrace_graph_addr
ftrace_graph_notrace_addr
ftrace_graph_addr_finish
ftrace_graph_ignore_func
print_graph_function_flags
ftrace_trace_task
ftrace_trace_task
ftrace_is_dead
ftrace_create_function_files
ftrace_destroy_function_files
ftrace_init_global_array_ops
ftrace_reset_array_ops
ftrace_init_tracefs
ftrace_init_tracefs_toplevel
ftrace_clear_pids
init_function_trace
ftrace_pid_follow_fork
register_ftrace_command
unregister_ftrace_command
clear_ftrace_function_probes
trace_parser_loaded
trace_parser_cont
trace_parser_clear
trace_branch_enable
trace_branch_disable
trace_branch_enable
trace_branch_disable
trace_buffer_unlock_commit
__trace_event_discard_commit
__event_trigger_test_discard
event_trigger_unlock_commit
event_trigger_unlock_commit_regs
is_string_field
is_function_field
event_file_data
register_trigger_hist_cmd
register_trigger_hist_enable_disable_cmds
event_command_post_trigger
event_command_needs_rec
init_ftrace_syscalls
get_syscall_name
trace_event_init
trace_event_eval_update
tracing_snapshot_instance
tracing_alloc_snapshot_instance
tracer_preempt_on
tracer_preempt_off
tracer_hardirqs_on
tracer_hardirqs_off
trace_iterator_reset
   1 // SPDX-License-Identifier: GPL-2.0
   2 
   3 #ifndef _LINUX_KERNEL_TRACE_H
   4 #define _LINUX_KERNEL_TRACE_H
   5 
   6 #include <linux/fs.h>
   7 #include <linux/atomic.h>
   8 #include <linux/sched.h>
   9 #include <linux/clocksource.h>
  10 #include <linux/ring_buffer.h>
  11 #include <linux/mmiotrace.h>
  12 #include <linux/tracepoint.h>
  13 #include <linux/ftrace.h>
  14 #include <linux/hw_breakpoint.h>
  15 #include <linux/trace_seq.h>
  16 #include <linux/trace_events.h>
  17 #include <linux/compiler.h>
  18 #include <linux/glob.h>
  19 
  20 #ifdef CONFIG_FTRACE_SYSCALLS
  21 #include <asm/unistd.h>         /* For NR_SYSCALLS           */
  22 #include <asm/syscall.h>        /* some archs define it here */
  23 #endif
  24 
  25 enum trace_type {
  26         __TRACE_FIRST_TYPE = 0,
  27 
  28         TRACE_FN,
  29         TRACE_CTX,
  30         TRACE_WAKE,
  31         TRACE_STACK,
  32         TRACE_PRINT,
  33         TRACE_BPRINT,
  34         TRACE_MMIO_RW,
  35         TRACE_MMIO_MAP,
  36         TRACE_BRANCH,
  37         TRACE_GRAPH_RET,
  38         TRACE_GRAPH_ENT,
  39         TRACE_USER_STACK,
  40         TRACE_BLK,
  41         TRACE_BPUTS,
  42         TRACE_HWLAT,
  43         TRACE_RAW_DATA,
  44 
  45         __TRACE_LAST_TYPE,
  46 };
  47 
  48 
  49 #undef __field
  50 #define __field(type, item)             type    item;
  51 
  52 #undef __field_struct
  53 #define __field_struct(type, item)      __field(type, item)
  54 
  55 #undef __field_desc
  56 #define __field_desc(type, container, item)
  57 
  58 #undef __array
  59 #define __array(type, item, size)       type    item[size];
  60 
  61 #undef __array_desc
  62 #define __array_desc(type, container, item, size)
  63 
  64 #undef __dynamic_array
  65 #define __dynamic_array(type, item)     type    item[];
  66 
  67 #undef F_STRUCT
  68 #define F_STRUCT(args...)               args
  69 
  70 #undef FTRACE_ENTRY
  71 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print, filter)     \
  72         struct struct_name {                                            \
  73                 struct trace_entry      ent;                            \
  74                 tstruct                                                 \
  75         }
  76 
  77 #undef FTRACE_ENTRY_DUP
  78 #define FTRACE_ENTRY_DUP(name, name_struct, id, tstruct, printk, filter)
  79 
  80 #undef FTRACE_ENTRY_REG
  81 #define FTRACE_ENTRY_REG(name, struct_name, id, tstruct, print, \
  82                          filter, regfn) \
  83         FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print), \
  84                      filter)
  85 
  86 #undef FTRACE_ENTRY_PACKED
  87 #define FTRACE_ENTRY_PACKED(name, struct_name, id, tstruct, print,      \
  88                             filter)                                     \
  89         FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print), \
  90                      filter) __packed
  91 
  92 #include "trace_entries.h"
  93 
  94 /*
  95  * syscalls are special, and need special handling, this is why
  96  * they are not included in trace_entries.h
  97  */
  98 struct syscall_trace_enter {
  99         struct trace_entry      ent;
 100         int                     nr;
 101         unsigned long           args[];
 102 };
 103 
 104 struct syscall_trace_exit {
 105         struct trace_entry      ent;
 106         int                     nr;
 107         long                    ret;
 108 };
 109 
 110 struct kprobe_trace_entry_head {
 111         struct trace_entry      ent;
 112         unsigned long           ip;
 113 };
 114 
 115 struct kretprobe_trace_entry_head {
 116         struct trace_entry      ent;
 117         unsigned long           func;
 118         unsigned long           ret_ip;
 119 };
 120 
 121 /*
 122  * trace_flag_type is an enumeration that holds different
 123  * states when a trace occurs. These are:
 124  *  IRQS_OFF            - interrupts were disabled
 125  *  IRQS_NOSUPPORT      - arch does not support irqs_disabled_flags
 126  *  NEED_RESCHED        - reschedule is requested
 127  *  HARDIRQ             - inside an interrupt handler
 128  *  SOFTIRQ             - inside a softirq handler
 129  */
 130 enum trace_flag_type {
 131         TRACE_FLAG_IRQS_OFF             = 0x01,
 132         TRACE_FLAG_IRQS_NOSUPPORT       = 0x02,
 133         TRACE_FLAG_NEED_RESCHED         = 0x04,
 134         TRACE_FLAG_HARDIRQ              = 0x08,
 135         TRACE_FLAG_SOFTIRQ              = 0x10,
 136         TRACE_FLAG_PREEMPT_RESCHED      = 0x20,
 137         TRACE_FLAG_NMI                  = 0x40,
 138 };
 139 
 140 #define TRACE_BUF_SIZE          1024
 141 
 142 struct trace_array;
 143 
 144 /*
 145  * The CPU trace array - it consists of thousands of trace entries
 146  * plus some other descriptor data: (for example which task started
 147  * the trace, etc.)
 148  */
 149 struct trace_array_cpu {
 150         atomic_t                disabled;
 151         void                    *buffer_page;   /* ring buffer spare */
 152 
 153         unsigned long           entries;
 154         unsigned long           saved_latency;
 155         unsigned long           critical_start;
 156         unsigned long           critical_end;
 157         unsigned long           critical_sequence;
 158         unsigned long           nice;
 159         unsigned long           policy;
 160         unsigned long           rt_priority;
 161         unsigned long           skipped_entries;
 162         u64                     preempt_timestamp;
 163         pid_t                   pid;
 164         kuid_t                  uid;
 165         char                    comm[TASK_COMM_LEN];
 166 
 167         bool                    ignore_pid;
 168 #ifdef CONFIG_FUNCTION_TRACER
 169         bool                    ftrace_ignore_pid;
 170 #endif
 171 };
 172 
 173 struct tracer;
 174 struct trace_option_dentry;
 175 
 176 struct trace_buffer {
 177         struct trace_array              *tr;
 178         struct ring_buffer              *buffer;
 179         struct trace_array_cpu __percpu *data;
 180         u64                             time_start;
 181         int                             cpu;
 182 };
 183 
 184 #define TRACE_FLAGS_MAX_SIZE            32
 185 
 186 struct trace_options {
 187         struct tracer                   *tracer;
 188         struct trace_option_dentry      *topts;
 189 };
 190 
 191 struct trace_pid_list {
 192         int                             pid_max;
 193         unsigned long                   *pids;
 194 };
 195 
 196 typedef bool (*cond_update_fn_t)(struct trace_array *tr, void *cond_data);
 197 
 198 /**
 199  * struct cond_snapshot - conditional snapshot data and callback
 200  *
 201  * The cond_snapshot structure encapsulates a callback function and
 202  * data associated with the snapshot for a given tracing instance.
 203  *
 204  * When a snapshot is taken conditionally, by invoking
 205  * tracing_snapshot_cond(tr, cond_data), the cond_data passed in is
 206  * passed in turn to the cond_snapshot.update() function.  That data
 207  * can be compared by the update() implementation with the cond_data
 208  * contained wihin the struct cond_snapshot instance associated with
 209  * the trace_array.  Because the tr->max_lock is held throughout the
 210  * update() call, the update() function can directly retrieve the
 211  * cond_snapshot and cond_data associated with the per-instance
 212  * snapshot associated with the trace_array.
 213  *
 214  * The cond_snapshot.update() implementation can save data to be
 215  * associated with the snapshot if it decides to, and returns 'true'
 216  * in that case, or it returns 'false' if the conditional snapshot
 217  * shouldn't be taken.
 218  *
 219  * The cond_snapshot instance is created and associated with the
 220  * user-defined cond_data by tracing_cond_snapshot_enable().
 221  * Likewise, the cond_snapshot instance is destroyed and is no longer
 222  * associated with the trace instance by
 223  * tracing_cond_snapshot_disable().
 224  *
 225  * The method below is required.
 226  *
 227  * @update: When a conditional snapshot is invoked, the update()
 228  *      callback function is invoked with the tr->max_lock held.  The
 229  *      update() implementation signals whether or not to actually
 230  *      take the snapshot, by returning 'true' if so, 'false' if no
 231  *      snapshot should be taken.  Because the max_lock is held for
 232  *      the duration of update(), the implementation is safe to
 233  *      directly retrieven and save any implementation data it needs
 234  *      to in association with the snapshot.
 235  */
 236 struct cond_snapshot {
 237         void                            *cond_data;
 238         cond_update_fn_t                update;
 239 };
 240 
 241 /*
 242  * The trace array - an array of per-CPU trace arrays. This is the
 243  * highest level data structure that individual tracers deal with.
 244  * They have on/off state as well:
 245  */
 246 struct trace_array {
 247         struct list_head        list;
 248         char                    *name;
 249         struct trace_buffer     trace_buffer;
 250 #ifdef CONFIG_TRACER_MAX_TRACE
 251         /*
 252          * The max_buffer is used to snapshot the trace when a maximum
 253          * latency is reached, or when the user initiates a snapshot.
 254          * Some tracers will use this to store a maximum trace while
 255          * it continues examining live traces.
 256          *
 257          * The buffers for the max_buffer are set up the same as the trace_buffer
 258          * When a snapshot is taken, the buffer of the max_buffer is swapped
 259          * with the buffer of the trace_buffer and the buffers are reset for
 260          * the trace_buffer so the tracing can continue.
 261          */
 262         struct trace_buffer     max_buffer;
 263         bool                    allocated_snapshot;
 264 #endif
 265 #if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
 266         unsigned long           max_latency;
 267 #endif
 268         struct trace_pid_list   __rcu *filtered_pids;
 269         /*
 270          * max_lock is used to protect the swapping of buffers
 271          * when taking a max snapshot. The buffers themselves are
 272          * protected by per_cpu spinlocks. But the action of the swap
 273          * needs its own lock.
 274          *
 275          * This is defined as a arch_spinlock_t in order to help
 276          * with performance when lockdep debugging is enabled.
 277          *
 278          * It is also used in other places outside the update_max_tr
 279          * so it needs to be defined outside of the
 280          * CONFIG_TRACER_MAX_TRACE.
 281          */
 282         arch_spinlock_t         max_lock;
 283         int                     buffer_disabled;
 284 #ifdef CONFIG_FTRACE_SYSCALLS
 285         int                     sys_refcount_enter;
 286         int                     sys_refcount_exit;
 287         struct trace_event_file __rcu *enter_syscall_files[NR_syscalls];
 288         struct trace_event_file __rcu *exit_syscall_files[NR_syscalls];
 289 #endif
 290         int                     stop_count;
 291         int                     clock_id;
 292         int                     nr_topts;
 293         bool                    clear_trace;
 294         int                     buffer_percent;
 295         unsigned int            n_err_log_entries;
 296         struct tracer           *current_trace;
 297         unsigned int            trace_flags;
 298         unsigned char           trace_flags_index[TRACE_FLAGS_MAX_SIZE];
 299         unsigned int            flags;
 300         raw_spinlock_t          start_lock;
 301         struct list_head        err_log;
 302         struct dentry           *dir;
 303         struct dentry           *options;
 304         struct dentry           *percpu_dir;
 305         struct dentry           *event_dir;
 306         struct trace_options    *topts;
 307         struct list_head        systems;
 308         struct list_head        events;
 309         struct trace_event_file *trace_marker_file;
 310         cpumask_var_t           tracing_cpumask; /* only trace on set CPUs */
 311         int                     ref;
 312 #ifdef CONFIG_FUNCTION_TRACER
 313         struct ftrace_ops       *ops;
 314         struct trace_pid_list   __rcu *function_pids;
 315 #ifdef CONFIG_DYNAMIC_FTRACE
 316         /* All of these are protected by the ftrace_lock */
 317         struct list_head        func_probes;
 318         struct list_head        mod_trace;
 319         struct list_head        mod_notrace;
 320 #endif
 321         /* function tracing enabled */
 322         int                     function_enabled;
 323 #endif
 324         int                     time_stamp_abs_ref;
 325         struct list_head        hist_vars;
 326 #ifdef CONFIG_TRACER_SNAPSHOT
 327         struct cond_snapshot    *cond_snapshot;
 328 #endif
 329 };
 330 
 331 enum {
 332         TRACE_ARRAY_FL_GLOBAL   = (1 << 0)
 333 };
 334 
 335 extern struct list_head ftrace_trace_arrays;
 336 
 337 extern struct mutex trace_types_lock;
 338 
 339 extern int trace_array_get(struct trace_array *tr);
 340 extern void trace_array_put(struct trace_array *tr);
 341 extern int tracing_check_open_get_tr(struct trace_array *tr);
 342 
 343 extern int tracing_set_time_stamp_abs(struct trace_array *tr, bool abs);
 344 extern int tracing_set_clock(struct trace_array *tr, const char *clockstr);
 345 
 346 extern bool trace_clock_in_ns(struct trace_array *tr);
 347 
 348 /*
 349  * The global tracer (top) should be the first trace array added,
 350  * but we check the flag anyway.
 351  */
 352 static inline struct trace_array *top_trace_array(void)
 353 {
 354         struct trace_array *tr;
 355 
 356         if (list_empty(&ftrace_trace_arrays))
 357                 return NULL;
 358 
 359         tr = list_entry(ftrace_trace_arrays.prev,
 360                         typeof(*tr), list);
 361         WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
 362         return tr;
 363 }
 364 
 365 #define FTRACE_CMP_TYPE(var, type) \
 366         __builtin_types_compatible_p(typeof(var), type *)
 367 
 368 #undef IF_ASSIGN
 369 #define IF_ASSIGN(var, entry, etype, id)                        \
 370         if (FTRACE_CMP_TYPE(var, etype)) {                      \
 371                 var = (typeof(var))(entry);                     \
 372                 WARN_ON(id != 0 && (entry)->type != id);        \
 373                 break;                                          \
 374         }
 375 
 376 /* Will cause compile errors if type is not found. */
 377 extern void __ftrace_bad_type(void);
 378 
 379 /*
 380  * The trace_assign_type is a verifier that the entry type is
 381  * the same as the type being assigned. To add new types simply
 382  * add a line with the following format:
 383  *
 384  * IF_ASSIGN(var, ent, type, id);
 385  *
 386  *  Where "type" is the trace type that includes the trace_entry
 387  *  as the "ent" item. And "id" is the trace identifier that is
 388  *  used in the trace_type enum.
 389  *
 390  *  If the type can have more than one id, then use zero.
 391  */
 392 #define trace_assign_type(var, ent)                                     \
 393         do {                                                            \
 394                 IF_ASSIGN(var, ent, struct ftrace_entry, TRACE_FN);     \
 395                 IF_ASSIGN(var, ent, struct ctx_switch_entry, 0);        \
 396                 IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK);   \
 397                 IF_ASSIGN(var, ent, struct userstack_entry, TRACE_USER_STACK);\
 398                 IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT);   \
 399                 IF_ASSIGN(var, ent, struct bprint_entry, TRACE_BPRINT); \
 400                 IF_ASSIGN(var, ent, struct bputs_entry, TRACE_BPUTS);   \
 401                 IF_ASSIGN(var, ent, struct hwlat_entry, TRACE_HWLAT);   \
 402                 IF_ASSIGN(var, ent, struct raw_data_entry, TRACE_RAW_DATA);\
 403                 IF_ASSIGN(var, ent, struct trace_mmiotrace_rw,          \
 404                           TRACE_MMIO_RW);                               \
 405                 IF_ASSIGN(var, ent, struct trace_mmiotrace_map,         \
 406                           TRACE_MMIO_MAP);                              \
 407                 IF_ASSIGN(var, ent, struct trace_branch, TRACE_BRANCH); \
 408                 IF_ASSIGN(var, ent, struct ftrace_graph_ent_entry,      \
 409                           TRACE_GRAPH_ENT);             \
 410                 IF_ASSIGN(var, ent, struct ftrace_graph_ret_entry,      \
 411                           TRACE_GRAPH_RET);             \
 412                 __ftrace_bad_type();                                    \
 413         } while (0)
 414 
 415 /*
 416  * An option specific to a tracer. This is a boolean value.
 417  * The bit is the bit index that sets its value on the
 418  * flags value in struct tracer_flags.
 419  */
 420 struct tracer_opt {
 421         const char      *name; /* Will appear on the trace_options file */
 422         u32             bit; /* Mask assigned in val field in tracer_flags */
 423 };
 424 
 425 /*
 426  * The set of specific options for a tracer. Your tracer
 427  * have to set the initial value of the flags val.
 428  */
 429 struct tracer_flags {
 430         u32                     val;
 431         struct tracer_opt       *opts;
 432         struct tracer           *trace;
 433 };
 434 
 435 /* Makes more easy to define a tracer opt */
 436 #define TRACER_OPT(s, b)        .name = #s, .bit = b
 437 
 438 
 439 struct trace_option_dentry {
 440         struct tracer_opt               *opt;
 441         struct tracer_flags             *flags;
 442         struct trace_array              *tr;
 443         struct dentry                   *entry;
 444 };
 445 
 446 /**
 447  * struct tracer - a specific tracer and its callbacks to interact with tracefs
 448  * @name: the name chosen to select it on the available_tracers file
 449  * @init: called when one switches to this tracer (echo name > current_tracer)
 450  * @reset: called when one switches to another tracer
 451  * @start: called when tracing is unpaused (echo 1 > tracing_on)
 452  * @stop: called when tracing is paused (echo 0 > tracing_on)
 453  * @update_thresh: called when tracing_thresh is updated
 454  * @open: called when the trace file is opened
 455  * @pipe_open: called when the trace_pipe file is opened
 456  * @close: called when the trace file is released
 457  * @pipe_close: called when the trace_pipe file is released
 458  * @read: override the default read callback on trace_pipe
 459  * @splice_read: override the default splice_read callback on trace_pipe
 460  * @selftest: selftest to run on boot (see trace_selftest.c)
 461  * @print_headers: override the first lines that describe your columns
 462  * @print_line: callback that prints a trace
 463  * @set_flag: signals one of your private flags changed (trace_options file)
 464  * @flags: your private flags
 465  */
 466 struct tracer {
 467         const char              *name;
 468         int                     (*init)(struct trace_array *tr);
 469         void                    (*reset)(struct trace_array *tr);
 470         void                    (*start)(struct trace_array *tr);
 471         void                    (*stop)(struct trace_array *tr);
 472         int                     (*update_thresh)(struct trace_array *tr);
 473         void                    (*open)(struct trace_iterator *iter);
 474         void                    (*pipe_open)(struct trace_iterator *iter);
 475         void                    (*close)(struct trace_iterator *iter);
 476         void                    (*pipe_close)(struct trace_iterator *iter);
 477         ssize_t                 (*read)(struct trace_iterator *iter,
 478                                         struct file *filp, char __user *ubuf,
 479                                         size_t cnt, loff_t *ppos);
 480         ssize_t                 (*splice_read)(struct trace_iterator *iter,
 481                                                struct file *filp,
 482                                                loff_t *ppos,
 483                                                struct pipe_inode_info *pipe,
 484                                                size_t len,
 485                                                unsigned int flags);
 486 #ifdef CONFIG_FTRACE_STARTUP_TEST
 487         int                     (*selftest)(struct tracer *trace,
 488                                             struct trace_array *tr);
 489 #endif
 490         void                    (*print_header)(struct seq_file *m);
 491         enum print_line_t       (*print_line)(struct trace_iterator *iter);
 492         /* If you handled the flag setting, return 0 */
 493         int                     (*set_flag)(struct trace_array *tr,
 494                                             u32 old_flags, u32 bit, int set);
 495         /* Return 0 if OK with change, else return non-zero */
 496         int                     (*flag_changed)(struct trace_array *tr,
 497                                                 u32 mask, int set);
 498         struct tracer           *next;
 499         struct tracer_flags     *flags;
 500         int                     enabled;
 501         int                     ref;
 502         bool                    print_max;
 503         bool                    allow_instances;
 504 #ifdef CONFIG_TRACER_MAX_TRACE
 505         bool                    use_max_tr;
 506 #endif
 507         /* True if tracer cannot be enabled in kernel param */
 508         bool                    noboot;
 509 };
 510 
 511 
 512 /* Only current can touch trace_recursion */
 513 
 514 /*
 515  * For function tracing recursion:
 516  *  The order of these bits are important.
 517  *
 518  *  When function tracing occurs, the following steps are made:
 519  *   If arch does not support a ftrace feature:
 520  *    call internal function (uses INTERNAL bits) which calls...
 521  *   If callback is registered to the "global" list, the list
 522  *    function is called and recursion checks the GLOBAL bits.
 523  *    then this function calls...
 524  *   The function callback, which can use the FTRACE bits to
 525  *    check for recursion.
 526  *
 527  * Now if the arch does not suppport a feature, and it calls
 528  * the global list function which calls the ftrace callback
 529  * all three of these steps will do a recursion protection.
 530  * There's no reason to do one if the previous caller already
 531  * did. The recursion that we are protecting against will
 532  * go through the same steps again.
 533  *
 534  * To prevent the multiple recursion checks, if a recursion
 535  * bit is set that is higher than the MAX bit of the current
 536  * check, then we know that the check was made by the previous
 537  * caller, and we can skip the current check.
 538  */
 539 enum {
 540         TRACE_BUFFER_BIT,
 541         TRACE_BUFFER_NMI_BIT,
 542         TRACE_BUFFER_IRQ_BIT,
 543         TRACE_BUFFER_SIRQ_BIT,
 544 
 545         /* Start of function recursion bits */
 546         TRACE_FTRACE_BIT,
 547         TRACE_FTRACE_NMI_BIT,
 548         TRACE_FTRACE_IRQ_BIT,
 549         TRACE_FTRACE_SIRQ_BIT,
 550 
 551         /* INTERNAL_BITs must be greater than FTRACE_BITs */
 552         TRACE_INTERNAL_BIT,
 553         TRACE_INTERNAL_NMI_BIT,
 554         TRACE_INTERNAL_IRQ_BIT,
 555         TRACE_INTERNAL_SIRQ_BIT,
 556 
 557         TRACE_BRANCH_BIT,
 558 /*
 559  * Abuse of the trace_recursion.
 560  * As we need a way to maintain state if we are tracing the function
 561  * graph in irq because we want to trace a particular function that
 562  * was called in irq context but we have irq tracing off. Since this
 563  * can only be modified by current, we can reuse trace_recursion.
 564  */
 565         TRACE_IRQ_BIT,
 566 
 567         /* Set if the function is in the set_graph_function file */
 568         TRACE_GRAPH_BIT,
 569 
 570         /*
 571          * In the very unlikely case that an interrupt came in
 572          * at a start of graph tracing, and we want to trace
 573          * the function in that interrupt, the depth can be greater
 574          * than zero, because of the preempted start of a previous
 575          * trace. In an even more unlikely case, depth could be 2
 576          * if a softirq interrupted the start of graph tracing,
 577          * followed by an interrupt preempting a start of graph
 578          * tracing in the softirq, and depth can even be 3
 579          * if an NMI came in at the start of an interrupt function
 580          * that preempted a softirq start of a function that
 581          * preempted normal context!!!! Luckily, it can't be
 582          * greater than 3, so the next two bits are a mask
 583          * of what the depth is when we set TRACE_GRAPH_BIT
 584          */
 585 
 586         TRACE_GRAPH_DEPTH_START_BIT,
 587         TRACE_GRAPH_DEPTH_END_BIT,
 588 
 589         /*
 590          * To implement set_graph_notrace, if this bit is set, we ignore
 591          * function graph tracing of called functions, until the return
 592          * function is called to clear it.
 593          */
 594         TRACE_GRAPH_NOTRACE_BIT,
 595 };
 596 
 597 #define trace_recursion_set(bit)        do { (current)->trace_recursion |= (1<<(bit)); } while (0)
 598 #define trace_recursion_clear(bit)      do { (current)->trace_recursion &= ~(1<<(bit)); } while (0)
 599 #define trace_recursion_test(bit)       ((current)->trace_recursion & (1<<(bit)))
 600 
 601 #define trace_recursion_depth() \
 602         (((current)->trace_recursion >> TRACE_GRAPH_DEPTH_START_BIT) & 3)
 603 #define trace_recursion_set_depth(depth) \
 604         do {                                                            \
 605                 current->trace_recursion &=                             \
 606                         ~(3 << TRACE_GRAPH_DEPTH_START_BIT);            \
 607                 current->trace_recursion |=                             \
 608                         ((depth) & 3) << TRACE_GRAPH_DEPTH_START_BIT;   \
 609         } while (0)
 610 
 611 #define TRACE_CONTEXT_BITS      4
 612 
 613 #define TRACE_FTRACE_START      TRACE_FTRACE_BIT
 614 #define TRACE_FTRACE_MAX        ((1 << (TRACE_FTRACE_START + TRACE_CONTEXT_BITS)) - 1)
 615 
 616 #define TRACE_LIST_START        TRACE_INTERNAL_BIT
 617 #define TRACE_LIST_MAX          ((1 << (TRACE_LIST_START + TRACE_CONTEXT_BITS)) - 1)
 618 
 619 #define TRACE_CONTEXT_MASK      TRACE_LIST_MAX
 620 
 621 static __always_inline int trace_get_context_bit(void)
 622 {
 623         int bit;
 624 
 625         if (in_interrupt()) {
 626                 if (in_nmi())
 627                         bit = 0;
 628 
 629                 else if (in_irq())
 630                         bit = 1;
 631                 else
 632                         bit = 2;
 633         } else
 634                 bit = 3;
 635 
 636         return bit;
 637 }
 638 
 639 static __always_inline int trace_test_and_set_recursion(int start, int max)
 640 {
 641         unsigned int val = current->trace_recursion;
 642         int bit;
 643 
 644         /* A previous recursion check was made */
 645         if ((val & TRACE_CONTEXT_MASK) > max)
 646                 return 0;
 647 
 648         bit = trace_get_context_bit() + start;
 649         if (unlikely(val & (1 << bit)))
 650                 return -1;
 651 
 652         val |= 1 << bit;
 653         current->trace_recursion = val;
 654         barrier();
 655 
 656         return bit;
 657 }
 658 
 659 static __always_inline void trace_clear_recursion(int bit)
 660 {
 661         unsigned int val = current->trace_recursion;
 662 
 663         if (!bit)
 664                 return;
 665 
 666         bit = 1 << bit;
 667         val &= ~bit;
 668 
 669         barrier();
 670         current->trace_recursion = val;
 671 }
 672 
 673 static inline struct ring_buffer_iter *
 674 trace_buffer_iter(struct trace_iterator *iter, int cpu)
 675 {
 676         return iter->buffer_iter ? iter->buffer_iter[cpu] : NULL;
 677 }
 678 
 679 int tracer_init(struct tracer *t, struct trace_array *tr);
 680 int tracing_is_enabled(void);
 681 void tracing_reset_online_cpus(struct trace_buffer *buf);
 682 void tracing_reset_current(int cpu);
 683 void tracing_reset_all_online_cpus(void);
 684 int tracing_open_generic(struct inode *inode, struct file *filp);
 685 int tracing_open_generic_tr(struct inode *inode, struct file *filp);
 686 bool tracing_is_disabled(void);
 687 bool tracer_tracing_is_on(struct trace_array *tr);
 688 void tracer_tracing_on(struct trace_array *tr);
 689 void tracer_tracing_off(struct trace_array *tr);
 690 struct dentry *trace_create_file(const char *name,
 691                                  umode_t mode,
 692                                  struct dentry *parent,
 693                                  void *data,
 694                                  const struct file_operations *fops);
 695 
 696 struct dentry *tracing_init_dentry(void);
 697 
 698 struct ring_buffer_event;
 699 
 700 struct ring_buffer_event *
 701 trace_buffer_lock_reserve(struct ring_buffer *buffer,
 702                           int type,
 703                           unsigned long len,
 704                           unsigned long flags,
 705                           int pc);
 706 
 707 struct trace_entry *tracing_get_trace_entry(struct trace_array *tr,
 708                                                 struct trace_array_cpu *data);
 709 
 710 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
 711                                           int *ent_cpu, u64 *ent_ts);
 712 
 713 void trace_buffer_unlock_commit_nostack(struct ring_buffer *buffer,
 714                                         struct ring_buffer_event *event);
 715 
 716 int trace_empty(struct trace_iterator *iter);
 717 
 718 void *trace_find_next_entry_inc(struct trace_iterator *iter);
 719 
 720 void trace_init_global_iter(struct trace_iterator *iter);
 721 
 722 void tracing_iter_reset(struct trace_iterator *iter, int cpu);
 723 
 724 unsigned long trace_total_entries_cpu(struct trace_array *tr, int cpu);
 725 unsigned long trace_total_entries(struct trace_array *tr);
 726 
 727 void trace_function(struct trace_array *tr,
 728                     unsigned long ip,
 729                     unsigned long parent_ip,
 730                     unsigned long flags, int pc);
 731 void trace_graph_function(struct trace_array *tr,
 732                     unsigned long ip,
 733                     unsigned long parent_ip,
 734                     unsigned long flags, int pc);
 735 void trace_latency_header(struct seq_file *m);
 736 void trace_default_header(struct seq_file *m);
 737 void print_trace_header(struct seq_file *m, struct trace_iterator *iter);
 738 int trace_empty(struct trace_iterator *iter);
 739 
 740 void trace_graph_return(struct ftrace_graph_ret *trace);
 741 int trace_graph_entry(struct ftrace_graph_ent *trace);
 742 void set_graph_array(struct trace_array *tr);
 743 
 744 void tracing_start_cmdline_record(void);
 745 void tracing_stop_cmdline_record(void);
 746 void tracing_start_tgid_record(void);
 747 void tracing_stop_tgid_record(void);
 748 
 749 int register_tracer(struct tracer *type);
 750 int is_tracing_stopped(void);
 751 
 752 loff_t tracing_lseek(struct file *file, loff_t offset, int whence);
 753 
 754 extern cpumask_var_t __read_mostly tracing_buffer_mask;
 755 
 756 #define for_each_tracing_cpu(cpu)       \
 757         for_each_cpu(cpu, tracing_buffer_mask)
 758 
 759 extern unsigned long nsecs_to_usecs(unsigned long nsecs);
 760 
 761 extern unsigned long tracing_thresh;
 762 
 763 /* PID filtering */
 764 
 765 extern int pid_max;
 766 
 767 bool trace_find_filtered_pid(struct trace_pid_list *filtered_pids,
 768                              pid_t search_pid);
 769 bool trace_ignore_this_task(struct trace_pid_list *filtered_pids,
 770                             struct task_struct *task);
 771 void trace_filter_add_remove_task(struct trace_pid_list *pid_list,
 772                                   struct task_struct *self,
 773                                   struct task_struct *task);
 774 void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos);
 775 void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos);
 776 int trace_pid_show(struct seq_file *m, void *v);
 777 void trace_free_pid_list(struct trace_pid_list *pid_list);
 778 int trace_pid_write(struct trace_pid_list *filtered_pids,
 779                     struct trace_pid_list **new_pid_list,
 780                     const char __user *ubuf, size_t cnt);
 781 
 782 #ifdef CONFIG_TRACER_MAX_TRACE
 783 void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu,
 784                    void *cond_data);
 785 void update_max_tr_single(struct trace_array *tr,
 786                           struct task_struct *tsk, int cpu);
 787 #endif /* CONFIG_TRACER_MAX_TRACE */
 788 
 789 #ifdef CONFIG_STACKTRACE
 790 void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
 791                    int pc);
 792 #else
 793 static inline void __trace_stack(struct trace_array *tr, unsigned long flags,
 794                                  int skip, int pc)
 795 {
 796 }
 797 #endif /* CONFIG_STACKTRACE */
 798 
 799 extern u64 ftrace_now(int cpu);
 800 
 801 extern void trace_find_cmdline(int pid, char comm[]);
 802 extern int trace_find_tgid(int pid);
 803 extern void trace_event_follow_fork(struct trace_array *tr, bool enable);
 804 
 805 #ifdef CONFIG_DYNAMIC_FTRACE
 806 extern unsigned long ftrace_update_tot_cnt;
 807 void ftrace_init_trace_array(struct trace_array *tr);
 808 #else
 809 static inline void ftrace_init_trace_array(struct trace_array *tr) { }
 810 #endif
 811 #define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func
 812 extern int DYN_FTRACE_TEST_NAME(void);
 813 #define DYN_FTRACE_TEST_NAME2 trace_selftest_dynamic_test_func2
 814 extern int DYN_FTRACE_TEST_NAME2(void);
 815 
 816 extern bool ring_buffer_expanded;
 817 extern bool tracing_selftest_disabled;
 818 
 819 #ifdef CONFIG_FTRACE_STARTUP_TEST
 820 extern int trace_selftest_startup_function(struct tracer *trace,
 821                                            struct trace_array *tr);
 822 extern int trace_selftest_startup_function_graph(struct tracer *trace,
 823                                                  struct trace_array *tr);
 824 extern int trace_selftest_startup_irqsoff(struct tracer *trace,
 825                                           struct trace_array *tr);
 826 extern int trace_selftest_startup_preemptoff(struct tracer *trace,
 827                                              struct trace_array *tr);
 828 extern int trace_selftest_startup_preemptirqsoff(struct tracer *trace,
 829                                                  struct trace_array *tr);
 830 extern int trace_selftest_startup_wakeup(struct tracer *trace,
 831                                          struct trace_array *tr);
 832 extern int trace_selftest_startup_nop(struct tracer *trace,
 833                                          struct trace_array *tr);
 834 extern int trace_selftest_startup_branch(struct tracer *trace,
 835                                          struct trace_array *tr);
 836 /*
 837  * Tracer data references selftest functions that only occur
 838  * on boot up. These can be __init functions. Thus, when selftests
 839  * are enabled, then the tracers need to reference __init functions.
 840  */
 841 #define __tracer_data           __refdata
 842 #else
 843 /* Tracers are seldom changed. Optimize when selftests are disabled. */
 844 #define __tracer_data           __read_mostly
 845 #endif /* CONFIG_FTRACE_STARTUP_TEST */
 846 
 847 extern void *head_page(struct trace_array_cpu *data);
 848 extern unsigned long long ns2usecs(u64 nsec);
 849 extern int
 850 trace_vbprintk(unsigned long ip, const char *fmt, va_list args);
 851 extern int
 852 trace_vprintk(unsigned long ip, const char *fmt, va_list args);
 853 extern int
 854 trace_array_vprintk(struct trace_array *tr,
 855                     unsigned long ip, const char *fmt, va_list args);
 856 int trace_array_printk(struct trace_array *tr,
 857                        unsigned long ip, const char *fmt, ...);
 858 int trace_array_printk_buf(struct ring_buffer *buffer,
 859                            unsigned long ip, const char *fmt, ...);
 860 void trace_printk_seq(struct trace_seq *s);
 861 enum print_line_t print_trace_line(struct trace_iterator *iter);
 862 
 863 extern char trace_find_mark(unsigned long long duration);
 864 
 865 struct ftrace_hash;
 866 
 867 struct ftrace_mod_load {
 868         struct list_head        list;
 869         char                    *func;
 870         char                    *module;
 871         int                      enable;
 872 };
 873 
 874 enum {
 875         FTRACE_HASH_FL_MOD      = (1 << 0),
 876 };
 877 
 878 struct ftrace_hash {
 879         unsigned long           size_bits;
 880         struct hlist_head       *buckets;
 881         unsigned long           count;
 882         unsigned long           flags;
 883         struct rcu_head         rcu;
 884 };
 885 
 886 struct ftrace_func_entry *
 887 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip);
 888 
 889 static __always_inline bool ftrace_hash_empty(struct ftrace_hash *hash)
 890 {
 891         return !hash || !(hash->count || (hash->flags & FTRACE_HASH_FL_MOD));
 892 }
 893 
 894 /* Standard output formatting function used for function return traces */
 895 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 896 
 897 /* Flag options */
 898 #define TRACE_GRAPH_PRINT_OVERRUN       0x1
 899 #define TRACE_GRAPH_PRINT_CPU           0x2
 900 #define TRACE_GRAPH_PRINT_OVERHEAD      0x4
 901 #define TRACE_GRAPH_PRINT_PROC          0x8
 902 #define TRACE_GRAPH_PRINT_DURATION      0x10
 903 #define TRACE_GRAPH_PRINT_ABS_TIME      0x20
 904 #define TRACE_GRAPH_PRINT_REL_TIME      0x40
 905 #define TRACE_GRAPH_PRINT_IRQS          0x80
 906 #define TRACE_GRAPH_PRINT_TAIL          0x100
 907 #define TRACE_GRAPH_SLEEP_TIME          0x200
 908 #define TRACE_GRAPH_GRAPH_TIME          0x400
 909 #define TRACE_GRAPH_PRINT_FILL_SHIFT    28
 910 #define TRACE_GRAPH_PRINT_FILL_MASK     (0x3 << TRACE_GRAPH_PRINT_FILL_SHIFT)
 911 
 912 extern void ftrace_graph_sleep_time_control(bool enable);
 913 
 914 #ifdef CONFIG_FUNCTION_PROFILER
 915 extern void ftrace_graph_graph_time_control(bool enable);
 916 #else
 917 static inline void ftrace_graph_graph_time_control(bool enable) { }
 918 #endif
 919 
 920 extern enum print_line_t
 921 print_graph_function_flags(struct trace_iterator *iter, u32 flags);
 922 extern void print_graph_headers_flags(struct seq_file *s, u32 flags);
 923 extern void
 924 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s);
 925 extern void graph_trace_open(struct trace_iterator *iter);
 926 extern void graph_trace_close(struct trace_iterator *iter);
 927 extern int __trace_graph_entry(struct trace_array *tr,
 928                                struct ftrace_graph_ent *trace,
 929                                unsigned long flags, int pc);
 930 extern void __trace_graph_return(struct trace_array *tr,
 931                                  struct ftrace_graph_ret *trace,
 932                                  unsigned long flags, int pc);
 933 
 934 #ifdef CONFIG_DYNAMIC_FTRACE
 935 extern struct ftrace_hash __rcu *ftrace_graph_hash;
 936 extern struct ftrace_hash __rcu *ftrace_graph_notrace_hash;
 937 
 938 static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
 939 {
 940         unsigned long addr = trace->func;
 941         int ret = 0;
 942         struct ftrace_hash *hash;
 943 
 944         preempt_disable_notrace();
 945 
 946         /*
 947          * Have to open code "rcu_dereference_sched()" because the
 948          * function graph tracer can be called when RCU is not
 949          * "watching".
 950          * Protected with schedule_on_each_cpu(ftrace_sync)
 951          */
 952         hash = rcu_dereference_protected(ftrace_graph_hash, !preemptible());
 953 
 954         if (ftrace_hash_empty(hash)) {
 955                 ret = 1;
 956                 goto out;
 957         }
 958 
 959         if (ftrace_lookup_ip(hash, addr)) {
 960 
 961                 /*
 962                  * This needs to be cleared on the return functions
 963                  * when the depth is zero.
 964                  */
 965                 trace_recursion_set(TRACE_GRAPH_BIT);
 966                 trace_recursion_set_depth(trace->depth);
 967 
 968                 /*
 969                  * If no irqs are to be traced, but a set_graph_function
 970                  * is set, and called by an interrupt handler, we still
 971                  * want to trace it.
 972                  */
 973                 if (in_irq())
 974                         trace_recursion_set(TRACE_IRQ_BIT);
 975                 else
 976                         trace_recursion_clear(TRACE_IRQ_BIT);
 977                 ret = 1;
 978         }
 979 
 980 out:
 981         preempt_enable_notrace();
 982         return ret;
 983 }
 984 
 985 static inline void ftrace_graph_addr_finish(struct ftrace_graph_ret *trace)
 986 {
 987         if (trace_recursion_test(TRACE_GRAPH_BIT) &&
 988             trace->depth == trace_recursion_depth())
 989                 trace_recursion_clear(TRACE_GRAPH_BIT);
 990 }
 991 
 992 static inline int ftrace_graph_notrace_addr(unsigned long addr)
 993 {
 994         int ret = 0;
 995         struct ftrace_hash *notrace_hash;
 996 
 997         preempt_disable_notrace();
 998 
 999         /*
1000          * Have to open code "rcu_dereference_sched()" because the
1001          * function graph tracer can be called when RCU is not
1002          * "watching".
1003          * Protected with schedule_on_each_cpu(ftrace_sync)
1004          */
1005         notrace_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
1006                                                  !preemptible());
1007 
1008         if (ftrace_lookup_ip(notrace_hash, addr))
1009                 ret = 1;
1010 
1011         preempt_enable_notrace();
1012         return ret;
1013 }
1014 #else
1015 static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
1016 {
1017         return 1;
1018 }
1019 
1020 static inline int ftrace_graph_notrace_addr(unsigned long addr)
1021 {
1022         return 0;
1023 }
1024 static inline void ftrace_graph_addr_finish(struct ftrace_graph_ret *trace)
1025 { }
1026 #endif /* CONFIG_DYNAMIC_FTRACE */
1027 
1028 extern unsigned int fgraph_max_depth;
1029 
1030 static inline bool ftrace_graph_ignore_func(struct ftrace_graph_ent *trace)
1031 {
1032         /* trace it when it is-nested-in or is a function enabled. */
1033         return !(trace_recursion_test(TRACE_GRAPH_BIT) ||
1034                  ftrace_graph_addr(trace)) ||
1035                 (trace->depth < 0) ||
1036                 (fgraph_max_depth && trace->depth >= fgraph_max_depth);
1037 }
1038 
1039 #else /* CONFIG_FUNCTION_GRAPH_TRACER */
1040 static inline enum print_line_t
1041 print_graph_function_flags(struct trace_iterator *iter, u32 flags)
1042 {
1043         return TRACE_TYPE_UNHANDLED;
1044 }
1045 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1046 
1047 extern struct list_head ftrace_pids;
1048 
1049 #ifdef CONFIG_FUNCTION_TRACER
1050 struct ftrace_func_command {
1051         struct list_head        list;
1052         char                    *name;
1053         int                     (*func)(struct trace_array *tr,
1054                                         struct ftrace_hash *hash,
1055                                         char *func, char *cmd,
1056                                         char *params, int enable);
1057 };
1058 extern bool ftrace_filter_param __initdata;
1059 static inline int ftrace_trace_task(struct trace_array *tr)
1060 {
1061         return !this_cpu_read(tr->trace_buffer.data->ftrace_ignore_pid);
1062 }
1063 extern int ftrace_is_dead(void);
1064 int ftrace_create_function_files(struct trace_array *tr,
1065                                  struct dentry *parent);
1066 void ftrace_destroy_function_files(struct trace_array *tr);
1067 void ftrace_init_global_array_ops(struct trace_array *tr);
1068 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func);
1069 void ftrace_reset_array_ops(struct trace_array *tr);
1070 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer);
1071 void ftrace_init_tracefs_toplevel(struct trace_array *tr,
1072                                   struct dentry *d_tracer);
1073 void ftrace_clear_pids(struct trace_array *tr);
1074 int init_function_trace(void);
1075 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable);
1076 #else
1077 static inline int ftrace_trace_task(struct trace_array *tr)
1078 {
1079         return 1;
1080 }
1081 static inline int ftrace_is_dead(void) { return 0; }
1082 static inline int
1083 ftrace_create_function_files(struct trace_array *tr,
1084                              struct dentry *parent)
1085 {
1086         return 0;
1087 }
1088 static inline void ftrace_destroy_function_files(struct trace_array *tr) { }
1089 static inline __init void
1090 ftrace_init_global_array_ops(struct trace_array *tr) { }
1091 static inline void ftrace_reset_array_ops(struct trace_array *tr) { }
1092 static inline void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d) { }
1093 static inline void ftrace_init_tracefs_toplevel(struct trace_array *tr, struct dentry *d) { }
1094 static inline void ftrace_clear_pids(struct trace_array *tr) { }
1095 static inline int init_function_trace(void) { return 0; }
1096 static inline void ftrace_pid_follow_fork(struct trace_array *tr, bool enable) { }
1097 /* ftace_func_t type is not defined, use macro instead of static inline */
1098 #define ftrace_init_array_ops(tr, func) do { } while (0)
1099 #endif /* CONFIG_FUNCTION_TRACER */
1100 
1101 #if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_DYNAMIC_FTRACE)
1102 
1103 struct ftrace_probe_ops {
1104         void                    (*func)(unsigned long ip,
1105                                         unsigned long parent_ip,
1106                                         struct trace_array *tr,
1107                                         struct ftrace_probe_ops *ops,
1108                                         void *data);
1109         int                     (*init)(struct ftrace_probe_ops *ops,
1110                                         struct trace_array *tr,
1111                                         unsigned long ip, void *init_data,
1112                                         void **data);
1113         void                    (*free)(struct ftrace_probe_ops *ops,
1114                                         struct trace_array *tr,
1115                                         unsigned long ip, void *data);
1116         int                     (*print)(struct seq_file *m,
1117                                          unsigned long ip,
1118                                          struct ftrace_probe_ops *ops,
1119                                          void *data);
1120 };
1121 
1122 struct ftrace_func_mapper;
1123 typedef int (*ftrace_mapper_func)(void *data);
1124 
1125 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void);
1126 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
1127                                            unsigned long ip);
1128 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
1129                                unsigned long ip, void *data);
1130 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
1131                                    unsigned long ip);
1132 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
1133                              ftrace_mapper_func free_func);
1134 
1135 extern int
1136 register_ftrace_function_probe(char *glob, struct trace_array *tr,
1137                                struct ftrace_probe_ops *ops, void *data);
1138 extern int
1139 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
1140                                       struct ftrace_probe_ops *ops);
1141 extern void clear_ftrace_function_probes(struct trace_array *tr);
1142 
1143 int register_ftrace_command(struct ftrace_func_command *cmd);
1144 int unregister_ftrace_command(struct ftrace_func_command *cmd);
1145 
1146 void ftrace_create_filter_files(struct ftrace_ops *ops,
1147                                 struct dentry *parent);
1148 void ftrace_destroy_filter_files(struct ftrace_ops *ops);
1149 #else
1150 struct ftrace_func_command;
1151 
1152 static inline __init int register_ftrace_command(struct ftrace_func_command *cmd)
1153 {
1154         return -EINVAL;
1155 }
1156 static inline __init int unregister_ftrace_command(char *cmd_name)
1157 {
1158         return -EINVAL;
1159 }
1160 static inline void clear_ftrace_function_probes(struct trace_array *tr)
1161 {
1162 }
1163 
1164 /*
1165  * The ops parameter passed in is usually undefined.
1166  * This must be a macro.
1167  */
1168 #define ftrace_create_filter_files(ops, parent) do { } while (0)
1169 #define ftrace_destroy_filter_files(ops) do { } while (0)
1170 #endif /* CONFIG_FUNCTION_TRACER && CONFIG_DYNAMIC_FTRACE */
1171 
1172 bool ftrace_event_is_function(struct trace_event_call *call);
1173 
1174 /*
1175  * struct trace_parser - servers for reading the user input separated by spaces
1176  * @cont: set if the input is not complete - no final space char was found
1177  * @buffer: holds the parsed user input
1178  * @idx: user input length
1179  * @size: buffer size
1180  */
1181 struct trace_parser {
1182         bool            cont;
1183         char            *buffer;
1184         unsigned        idx;
1185         unsigned        size;
1186 };
1187 
1188 static inline bool trace_parser_loaded(struct trace_parser *parser)
1189 {
1190         return (parser->idx != 0);
1191 }
1192 
1193 static inline bool trace_parser_cont(struct trace_parser *parser)
1194 {
1195         return parser->cont;
1196 }
1197 
1198 static inline void trace_parser_clear(struct trace_parser *parser)
1199 {
1200         parser->cont = false;
1201         parser->idx = 0;
1202 }
1203 
1204 extern int trace_parser_get_init(struct trace_parser *parser, int size);
1205 extern void trace_parser_put(struct trace_parser *parser);
1206 extern int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
1207         size_t cnt, loff_t *ppos);
1208 
1209 /*
1210  * Only create function graph options if function graph is configured.
1211  */
1212 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1213 # define FGRAPH_FLAGS                                           \
1214                 C(DISPLAY_GRAPH,        "display-graph"),
1215 #else
1216 # define FGRAPH_FLAGS
1217 #endif
1218 
1219 #ifdef CONFIG_BRANCH_TRACER
1220 # define BRANCH_FLAGS                                   \
1221                 C(BRANCH,               "branch"),
1222 #else
1223 # define BRANCH_FLAGS
1224 #endif
1225 
1226 #ifdef CONFIG_FUNCTION_TRACER
1227 # define FUNCTION_FLAGS                                         \
1228                 C(FUNCTION,             "function-trace"),      \
1229                 C(FUNC_FORK,            "function-fork"),
1230 # define FUNCTION_DEFAULT_FLAGS         TRACE_ITER_FUNCTION
1231 #else
1232 # define FUNCTION_FLAGS
1233 # define FUNCTION_DEFAULT_FLAGS         0UL
1234 # define TRACE_ITER_FUNC_FORK           0UL
1235 #endif
1236 
1237 #ifdef CONFIG_STACKTRACE
1238 # define STACK_FLAGS                            \
1239                 C(STACKTRACE,           "stacktrace"),
1240 #else
1241 # define STACK_FLAGS
1242 #endif
1243 
1244 /*
1245  * trace_iterator_flags is an enumeration that defines bit
1246  * positions into trace_flags that controls the output.
1247  *
1248  * NOTE: These bits must match the trace_options array in
1249  *       trace.c (this macro guarantees it).
1250  */
1251 #define TRACE_FLAGS                                             \
1252                 C(PRINT_PARENT,         "print-parent"),        \
1253                 C(SYM_OFFSET,           "sym-offset"),          \
1254                 C(SYM_ADDR,             "sym-addr"),            \
1255                 C(VERBOSE,              "verbose"),             \
1256                 C(RAW,                  "raw"),                 \
1257                 C(HEX,                  "hex"),                 \
1258                 C(BIN,                  "bin"),                 \
1259                 C(BLOCK,                "block"),               \
1260                 C(PRINTK,               "trace_printk"),        \
1261                 C(ANNOTATE,             "annotate"),            \
1262                 C(USERSTACKTRACE,       "userstacktrace"),      \
1263                 C(SYM_USEROBJ,          "sym-userobj"),         \
1264                 C(PRINTK_MSGONLY,       "printk-msg-only"),     \
1265                 C(CONTEXT_INFO,         "context-info"),   /* Print pid/cpu/time */ \
1266                 C(LATENCY_FMT,          "latency-format"),      \
1267                 C(RECORD_CMD,           "record-cmd"),          \
1268                 C(RECORD_TGID,          "record-tgid"),         \
1269                 C(OVERWRITE,            "overwrite"),           \
1270                 C(STOP_ON_FREE,         "disable_on_free"),     \
1271                 C(IRQ_INFO,             "irq-info"),            \
1272                 C(MARKERS,              "markers"),             \
1273                 C(EVENT_FORK,           "event-fork"),          \
1274                 FUNCTION_FLAGS                                  \
1275                 FGRAPH_FLAGS                                    \
1276                 STACK_FLAGS                                     \
1277                 BRANCH_FLAGS
1278 
1279 /*
1280  * By defining C, we can make TRACE_FLAGS a list of bit names
1281  * that will define the bits for the flag masks.
1282  */
1283 #undef C
1284 #define C(a, b) TRACE_ITER_##a##_BIT
1285 
1286 enum trace_iterator_bits {
1287         TRACE_FLAGS
1288         /* Make sure we don't go more than we have bits for */
1289         TRACE_ITER_LAST_BIT
1290 };
1291 
1292 /*
1293  * By redefining C, we can make TRACE_FLAGS a list of masks that
1294  * use the bits as defined above.
1295  */
1296 #undef C
1297 #define C(a, b) TRACE_ITER_##a = (1 << TRACE_ITER_##a##_BIT)
1298 
1299 enum trace_iterator_flags { TRACE_FLAGS };
1300 
1301 /*
1302  * TRACE_ITER_SYM_MASK masks the options in trace_flags that
1303  * control the output of kernel symbols.
1304  */
1305 #define TRACE_ITER_SYM_MASK \
1306         (TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)
1307 
1308 extern struct tracer nop_trace;
1309 
1310 #ifdef CONFIG_BRANCH_TRACER
1311 extern int enable_branch_tracing(struct trace_array *tr);
1312 extern void disable_branch_tracing(void);
1313 static inline int trace_branch_enable(struct trace_array *tr)
1314 {
1315         if (tr->trace_flags & TRACE_ITER_BRANCH)
1316                 return enable_branch_tracing(tr);
1317         return 0;
1318 }
1319 static inline void trace_branch_disable(void)
1320 {
1321         /* due to races, always disable */
1322         disable_branch_tracing();
1323 }
1324 #else
1325 static inline int trace_branch_enable(struct trace_array *tr)
1326 {
1327         return 0;
1328 }
1329 static inline void trace_branch_disable(void)
1330 {
1331 }
1332 #endif /* CONFIG_BRANCH_TRACER */
1333 
1334 /* set ring buffers to default size if not already done so */
1335 int tracing_update_buffers(void);
1336 
1337 struct ftrace_event_field {
1338         struct list_head        link;
1339         const char              *name;
1340         const char              *type;
1341         int                     filter_type;
1342         int                     offset;
1343         int                     size;
1344         int                     is_signed;
1345 };
1346 
1347 struct prog_entry;
1348 
1349 struct event_filter {
1350         struct prog_entry __rcu *prog;
1351         char                    *filter_string;
1352 };
1353 
1354 struct event_subsystem {
1355         struct list_head        list;
1356         const char              *name;
1357         struct event_filter     *filter;
1358         int                     ref_count;
1359 };
1360 
1361 struct trace_subsystem_dir {
1362         struct list_head                list;
1363         struct event_subsystem          *subsystem;
1364         struct trace_array              *tr;
1365         struct dentry                   *entry;
1366         int                             ref_count;
1367         int                             nr_events;
1368 };
1369 
1370 extern int call_filter_check_discard(struct trace_event_call *call, void *rec,
1371                                      struct ring_buffer *buffer,
1372                                      struct ring_buffer_event *event);
1373 
1374 void trace_buffer_unlock_commit_regs(struct trace_array *tr,
1375                                      struct ring_buffer *buffer,
1376                                      struct ring_buffer_event *event,
1377                                      unsigned long flags, int pc,
1378                                      struct pt_regs *regs);
1379 
1380 static inline void trace_buffer_unlock_commit(struct trace_array *tr,
1381                                               struct ring_buffer *buffer,
1382                                               struct ring_buffer_event *event,
1383                                               unsigned long flags, int pc)
1384 {
1385         trace_buffer_unlock_commit_regs(tr, buffer, event, flags, pc, NULL);
1386 }
1387 
1388 DECLARE_PER_CPU(struct ring_buffer_event *, trace_buffered_event);
1389 DECLARE_PER_CPU(int, trace_buffered_event_cnt);
1390 void trace_buffered_event_disable(void);
1391 void trace_buffered_event_enable(void);
1392 
1393 static inline void
1394 __trace_event_discard_commit(struct ring_buffer *buffer,
1395                              struct ring_buffer_event *event)
1396 {
1397         if (this_cpu_read(trace_buffered_event) == event) {
1398                 /* Simply release the temp buffer */
1399                 this_cpu_dec(trace_buffered_event_cnt);
1400                 return;
1401         }
1402         ring_buffer_discard_commit(buffer, event);
1403 }
1404 
1405 /*
1406  * Helper function for event_trigger_unlock_commit{_regs}().
1407  * If there are event triggers attached to this event that requires
1408  * filtering against its fields, then they wil be called as the
1409  * entry already holds the field information of the current event.
1410  *
1411  * It also checks if the event should be discarded or not.
1412  * It is to be discarded if the event is soft disabled and the
1413  * event was only recorded to process triggers, or if the event
1414  * filter is active and this event did not match the filters.
1415  *
1416  * Returns true if the event is discarded, false otherwise.
1417  */
1418 static inline bool
1419 __event_trigger_test_discard(struct trace_event_file *file,
1420                              struct ring_buffer *buffer,
1421                              struct ring_buffer_event *event,
1422                              void *entry,
1423                              enum event_trigger_type *tt)
1424 {
1425         unsigned long eflags = file->flags;
1426 
1427         if (eflags & EVENT_FILE_FL_TRIGGER_COND)
1428                 *tt = event_triggers_call(file, entry, event);
1429 
1430         if (test_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags) ||
1431             (unlikely(file->flags & EVENT_FILE_FL_FILTERED) &&
1432              !filter_match_preds(file->filter, entry))) {
1433                 __trace_event_discard_commit(buffer, event);
1434                 return true;
1435         }
1436 
1437         return false;
1438 }
1439 
1440 /**
1441  * event_trigger_unlock_commit - handle triggers and finish event commit
1442  * @file: The file pointer assoctiated to the event
1443  * @buffer: The ring buffer that the event is being written to
1444  * @event: The event meta data in the ring buffer
1445  * @entry: The event itself
1446  * @irq_flags: The state of the interrupts at the start of the event
1447  * @pc: The state of the preempt count at the start of the event.
1448  *
1449  * This is a helper function to handle triggers that require data
1450  * from the event itself. It also tests the event against filters and
1451  * if the event is soft disabled and should be discarded.
1452  */
1453 static inline void
1454 event_trigger_unlock_commit(struct trace_event_file *file,
1455                             struct ring_buffer *buffer,
1456                             struct ring_buffer_event *event,
1457                             void *entry, unsigned long irq_flags, int pc)
1458 {
1459         enum event_trigger_type tt = ETT_NONE;
1460 
1461         if (!__event_trigger_test_discard(file, buffer, event, entry, &tt))
1462                 trace_buffer_unlock_commit(file->tr, buffer, event, irq_flags, pc);
1463 
1464         if (tt)
1465                 event_triggers_post_call(file, tt);
1466 }
1467 
1468 /**
1469  * event_trigger_unlock_commit_regs - handle triggers and finish event commit
1470  * @file: The file pointer assoctiated to the event
1471  * @buffer: The ring buffer that the event is being written to
1472  * @event: The event meta data in the ring buffer
1473  * @entry: The event itself
1474  * @irq_flags: The state of the interrupts at the start of the event
1475  * @pc: The state of the preempt count at the start of the event.
1476  *
1477  * This is a helper function to handle triggers that require data
1478  * from the event itself. It also tests the event against filters and
1479  * if the event is soft disabled and should be discarded.
1480  *
1481  * Same as event_trigger_unlock_commit() but calls
1482  * trace_buffer_unlock_commit_regs() instead of trace_buffer_unlock_commit().
1483  */
1484 static inline void
1485 event_trigger_unlock_commit_regs(struct trace_event_file *file,
1486                                  struct ring_buffer *buffer,
1487                                  struct ring_buffer_event *event,
1488                                  void *entry, unsigned long irq_flags, int pc,
1489                                  struct pt_regs *regs)
1490 {
1491         enum event_trigger_type tt = ETT_NONE;
1492 
1493         if (!__event_trigger_test_discard(file, buffer, event, entry, &tt))
1494                 trace_buffer_unlock_commit_regs(file->tr, buffer, event,
1495                                                 irq_flags, pc, regs);
1496 
1497         if (tt)
1498                 event_triggers_post_call(file, tt);
1499 }
1500 
1501 #define FILTER_PRED_INVALID     ((unsigned short)-1)
1502 #define FILTER_PRED_IS_RIGHT    (1 << 15)
1503 #define FILTER_PRED_FOLD        (1 << 15)
1504 
1505 /*
1506  * The max preds is the size of unsigned short with
1507  * two flags at the MSBs. One bit is used for both the IS_RIGHT
1508  * and FOLD flags. The other is reserved.
1509  *
1510  * 2^14 preds is way more than enough.
1511  */
1512 #define MAX_FILTER_PRED         16384
1513 
1514 struct filter_pred;
1515 struct regex;
1516 
1517 typedef int (*filter_pred_fn_t) (struct filter_pred *pred, void *event);
1518 
1519 typedef int (*regex_match_func)(char *str, struct regex *r, int len);
1520 
1521 enum regex_type {
1522         MATCH_FULL = 0,
1523         MATCH_FRONT_ONLY,
1524         MATCH_MIDDLE_ONLY,
1525         MATCH_END_ONLY,
1526         MATCH_GLOB,
1527         MATCH_INDEX,
1528 };
1529 
1530 struct regex {
1531         char                    pattern[MAX_FILTER_STR_VAL];
1532         int                     len;
1533         int                     field_len;
1534         regex_match_func        match;
1535 };
1536 
1537 struct filter_pred {
1538         filter_pred_fn_t        fn;
1539         u64                     val;
1540         struct regex            regex;
1541         unsigned short          *ops;
1542         struct ftrace_event_field *field;
1543         int                     offset;
1544         int                     not;
1545         int                     op;
1546 };
1547 
1548 static inline bool is_string_field(struct ftrace_event_field *field)
1549 {
1550         return field->filter_type == FILTER_DYN_STRING ||
1551                field->filter_type == FILTER_STATIC_STRING ||
1552                field->filter_type == FILTER_PTR_STRING ||
1553                field->filter_type == FILTER_COMM;
1554 }
1555 
1556 static inline bool is_function_field(struct ftrace_event_field *field)
1557 {
1558         return field->filter_type == FILTER_TRACE_FN;
1559 }
1560 
1561 extern enum regex_type
1562 filter_parse_regex(char *buff, int len, char **search, int *not);
1563 extern void print_event_filter(struct trace_event_file *file,
1564                                struct trace_seq *s);
1565 extern int apply_event_filter(struct trace_event_file *file,
1566                               char *filter_string);
1567 extern int apply_subsystem_event_filter(struct trace_subsystem_dir *dir,
1568                                         char *filter_string);
1569 extern void print_subsystem_event_filter(struct event_subsystem *system,
1570                                          struct trace_seq *s);
1571 extern int filter_assign_type(const char *type);
1572 extern int create_event_filter(struct trace_array *tr,
1573                                struct trace_event_call *call,
1574                                char *filter_str, bool set_str,
1575                                struct event_filter **filterp);
1576 extern void free_event_filter(struct event_filter *filter);
1577 
1578 struct ftrace_event_field *
1579 trace_find_event_field(struct trace_event_call *call, char *name);
1580 
1581 extern void trace_event_enable_cmd_record(bool enable);
1582 extern void trace_event_enable_tgid_record(bool enable);
1583 
1584 extern int event_trace_init(void);
1585 extern int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr);
1586 extern int event_trace_del_tracer(struct trace_array *tr);
1587 
1588 extern struct trace_event_file *__find_event_file(struct trace_array *tr,
1589                                                   const char *system,
1590                                                   const char *event);
1591 extern struct trace_event_file *find_event_file(struct trace_array *tr,
1592                                                 const char *system,
1593                                                 const char *event);
1594 
1595 static inline void *event_file_data(struct file *filp)
1596 {
1597         return READ_ONCE(file_inode(filp)->i_private);
1598 }
1599 
1600 extern struct mutex event_mutex;
1601 extern struct list_head ftrace_events;
1602 
1603 extern const struct file_operations event_trigger_fops;
1604 extern const struct file_operations event_hist_fops;
1605 
1606 #ifdef CONFIG_HIST_TRIGGERS
1607 extern int register_trigger_hist_cmd(void);
1608 extern int register_trigger_hist_enable_disable_cmds(void);
1609 #else
1610 static inline int register_trigger_hist_cmd(void) { return 0; }
1611 static inline int register_trigger_hist_enable_disable_cmds(void) { return 0; }
1612 #endif
1613 
1614 extern int register_trigger_cmds(void);
1615 extern void clear_event_triggers(struct trace_array *tr);
1616 
1617 struct event_trigger_data {
1618         unsigned long                   count;
1619         int                             ref;
1620         struct event_trigger_ops        *ops;
1621         struct event_command            *cmd_ops;
1622         struct event_filter __rcu       *filter;
1623         char                            *filter_str;
1624         void                            *private_data;
1625         bool                            paused;
1626         bool                            paused_tmp;
1627         struct list_head                list;
1628         char                            *name;
1629         struct list_head                named_list;
1630         struct event_trigger_data       *named_data;
1631 };
1632 
1633 /* Avoid typos */
1634 #define ENABLE_EVENT_STR        "enable_event"
1635 #define DISABLE_EVENT_STR       "disable_event"
1636 #define ENABLE_HIST_STR         "enable_hist"
1637 #define DISABLE_HIST_STR        "disable_hist"
1638 
1639 struct enable_trigger_data {
1640         struct trace_event_file         *file;
1641         bool                            enable;
1642         bool                            hist;
1643 };
1644 
1645 extern int event_enable_trigger_print(struct seq_file *m,
1646                                       struct event_trigger_ops *ops,
1647                                       struct event_trigger_data *data);
1648 extern void event_enable_trigger_free(struct event_trigger_ops *ops,
1649                                       struct event_trigger_data *data);
1650 extern int event_enable_trigger_func(struct event_command *cmd_ops,
1651                                      struct trace_event_file *file,
1652                                      char *glob, char *cmd, char *param);
1653 extern int event_enable_register_trigger(char *glob,
1654                                          struct event_trigger_ops *ops,
1655                                          struct event_trigger_data *data,
1656                                          struct trace_event_file *file);
1657 extern void event_enable_unregister_trigger(char *glob,
1658                                             struct event_trigger_ops *ops,
1659                                             struct event_trigger_data *test,
1660                                             struct trace_event_file *file);
1661 extern void trigger_data_free(struct event_trigger_data *data);
1662 extern int event_trigger_init(struct event_trigger_ops *ops,
1663                               struct event_trigger_data *data);
1664 extern int trace_event_trigger_enable_disable(struct trace_event_file *file,
1665                                               int trigger_enable);
1666 extern void update_cond_flag(struct trace_event_file *file);
1667 extern int set_trigger_filter(char *filter_str,
1668                               struct event_trigger_data *trigger_data,
1669                               struct trace_event_file *file);
1670 extern struct event_trigger_data *find_named_trigger(const char *name);
1671 extern bool is_named_trigger(struct event_trigger_data *test);
1672 extern int save_named_trigger(const char *name,
1673                               struct event_trigger_data *data);
1674 extern void del_named_trigger(struct event_trigger_data *data);
1675 extern void pause_named_trigger(struct event_trigger_data *data);
1676 extern void unpause_named_trigger(struct event_trigger_data *data);
1677 extern void set_named_trigger_data(struct event_trigger_data *data,
1678                                    struct event_trigger_data *named_data);
1679 extern struct event_trigger_data *
1680 get_named_trigger_data(struct event_trigger_data *data);
1681 extern int register_event_command(struct event_command *cmd);
1682 extern int unregister_event_command(struct event_command *cmd);
1683 extern int register_trigger_hist_enable_disable_cmds(void);
1684 
1685 /**
1686  * struct event_trigger_ops - callbacks for trace event triggers
1687  *
1688  * The methods in this structure provide per-event trigger hooks for
1689  * various trigger operations.
1690  *
1691  * All the methods below, except for @init() and @free(), must be
1692  * implemented.
1693  *
1694  * @func: The trigger 'probe' function called when the triggering
1695  *      event occurs.  The data passed into this callback is the data
1696  *      that was supplied to the event_command @reg() function that
1697  *      registered the trigger (see struct event_command) along with
1698  *      the trace record, rec.
1699  *
1700  * @init: An optional initialization function called for the trigger
1701  *      when the trigger is registered (via the event_command reg()
1702  *      function).  This can be used to perform per-trigger
1703  *      initialization such as incrementing a per-trigger reference
1704  *      count, for instance.  This is usually implemented by the
1705  *      generic utility function @event_trigger_init() (see
1706  *      trace_event_triggers.c).
1707  *
1708  * @free: An optional de-initialization function called for the
1709  *      trigger when the trigger is unregistered (via the
1710  *      event_command @reg() function).  This can be used to perform
1711  *      per-trigger de-initialization such as decrementing a
1712  *      per-trigger reference count and freeing corresponding trigger
1713  *      data, for instance.  This is usually implemented by the
1714  *      generic utility function @event_trigger_free() (see
1715  *      trace_event_triggers.c).
1716  *
1717  * @print: The callback function invoked to have the trigger print
1718  *      itself.  This is usually implemented by a wrapper function
1719  *      that calls the generic utility function @event_trigger_print()
1720  *      (see trace_event_triggers.c).
1721  */
1722 struct event_trigger_ops {
1723         void                    (*func)(struct event_trigger_data *data,
1724                                         void *rec,
1725                                         struct ring_buffer_event *rbe);
1726         int                     (*init)(struct event_trigger_ops *ops,
1727                                         struct event_trigger_data *data);
1728         void                    (*free)(struct event_trigger_ops *ops,
1729                                         struct event_trigger_data *data);
1730         int                     (*print)(struct seq_file *m,
1731                                          struct event_trigger_ops *ops,
1732                                          struct event_trigger_data *data);
1733 };
1734 
1735 /**
1736  * struct event_command - callbacks and data members for event commands
1737  *
1738  * Event commands are invoked by users by writing the command name
1739  * into the 'trigger' file associated with a trace event.  The
1740  * parameters associated with a specific invocation of an event
1741  * command are used to create an event trigger instance, which is
1742  * added to the list of trigger instances associated with that trace
1743  * event.  When the event is hit, the set of triggers associated with
1744  * that event is invoked.
1745  *
1746  * The data members in this structure provide per-event command data
1747  * for various event commands.
1748  *
1749  * All the data members below, except for @post_trigger, must be set
1750  * for each event command.
1751  *
1752  * @name: The unique name that identifies the event command.  This is
1753  *      the name used when setting triggers via trigger files.
1754  *
1755  * @trigger_type: A unique id that identifies the event command
1756  *      'type'.  This value has two purposes, the first to ensure that
1757  *      only one trigger of the same type can be set at a given time
1758  *      for a particular event e.g. it doesn't make sense to have both
1759  *      a traceon and traceoff trigger attached to a single event at
1760  *      the same time, so traceon and traceoff have the same type
1761  *      though they have different names.  The @trigger_type value is
1762  *      also used as a bit value for deferring the actual trigger
1763  *      action until after the current event is finished.  Some
1764  *      commands need to do this if they themselves log to the trace
1765  *      buffer (see the @post_trigger() member below).  @trigger_type
1766  *      values are defined by adding new values to the trigger_type
1767  *      enum in include/linux/trace_events.h.
1768  *
1769  * @flags: See the enum event_command_flags below.
1770  *
1771  * All the methods below, except for @set_filter() and @unreg_all(),
1772  * must be implemented.
1773  *
1774  * @func: The callback function responsible for parsing and
1775  *      registering the trigger written to the 'trigger' file by the
1776  *      user.  It allocates the trigger instance and registers it with
1777  *      the appropriate trace event.  It makes use of the other
1778  *      event_command callback functions to orchestrate this, and is
1779  *      usually implemented by the generic utility function
1780  *      @event_trigger_callback() (see trace_event_triggers.c).
1781  *
1782  * @reg: Adds the trigger to the list of triggers associated with the
1783  *      event, and enables the event trigger itself, after
1784  *      initializing it (via the event_trigger_ops @init() function).
1785  *      This is also where commands can use the @trigger_type value to
1786  *      make the decision as to whether or not multiple instances of
1787  *      the trigger should be allowed.  This is usually implemented by
1788  *      the generic utility function @register_trigger() (see
1789  *      trace_event_triggers.c).
1790  *
1791  * @unreg: Removes the trigger from the list of triggers associated
1792  *      with the event, and disables the event trigger itself, after
1793  *      initializing it (via the event_trigger_ops @free() function).
1794  *      This is usually implemented by the generic utility function
1795  *      @unregister_trigger() (see trace_event_triggers.c).
1796  *
1797  * @unreg_all: An optional function called to remove all the triggers
1798  *      from the list of triggers associated with the event.  Called
1799  *      when a trigger file is opened in truncate mode.
1800  *
1801  * @set_filter: An optional function called to parse and set a filter
1802  *      for the trigger.  If no @set_filter() method is set for the
1803  *      event command, filters set by the user for the command will be
1804  *      ignored.  This is usually implemented by the generic utility
1805  *      function @set_trigger_filter() (see trace_event_triggers.c).
1806  *
1807  * @get_trigger_ops: The callback function invoked to retrieve the
1808  *      event_trigger_ops implementation associated with the command.
1809  */
1810 struct event_command {
1811         struct list_head        list;
1812         char                    *name;
1813         enum event_trigger_type trigger_type;
1814         int                     flags;
1815         int                     (*func)(struct event_command *cmd_ops,
1816                                         struct trace_event_file *file,
1817                                         char *glob, char *cmd, char *params);
1818         int                     (*reg)(char *glob,
1819                                        struct event_trigger_ops *ops,
1820                                        struct event_trigger_data *data,
1821                                        struct trace_event_file *file);
1822         void                    (*unreg)(char *glob,
1823                                          struct event_trigger_ops *ops,
1824                                          struct event_trigger_data *data,
1825                                          struct trace_event_file *file);
1826         void                    (*unreg_all)(struct trace_event_file *file);
1827         int                     (*set_filter)(char *filter_str,
1828                                               struct event_trigger_data *data,
1829                                               struct trace_event_file *file);
1830         struct event_trigger_ops *(*get_trigger_ops)(char *cmd, char *param);
1831 };
1832 
1833 /**
1834  * enum event_command_flags - flags for struct event_command
1835  *
1836  * @POST_TRIGGER: A flag that says whether or not this command needs
1837  *      to have its action delayed until after the current event has
1838  *      been closed.  Some triggers need to avoid being invoked while
1839  *      an event is currently in the process of being logged, since
1840  *      the trigger may itself log data into the trace buffer.  Thus
1841  *      we make sure the current event is committed before invoking
1842  *      those triggers.  To do that, the trigger invocation is split
1843  *      in two - the first part checks the filter using the current
1844  *      trace record; if a command has the @post_trigger flag set, it
1845  *      sets a bit for itself in the return value, otherwise it
1846  *      directly invokes the trigger.  Once all commands have been
1847  *      either invoked or set their return flag, the current record is
1848  *      either committed or discarded.  At that point, if any commands
1849  *      have deferred their triggers, those commands are finally
1850  *      invoked following the close of the current event.  In other
1851  *      words, if the event_trigger_ops @func() probe implementation
1852  *      itself logs to the trace buffer, this flag should be set,
1853  *      otherwise it can be left unspecified.
1854  *
1855  * @NEEDS_REC: A flag that says whether or not this command needs
1856  *      access to the trace record in order to perform its function,
1857  *      regardless of whether or not it has a filter associated with
1858  *      it (filters make a trigger require access to the trace record
1859  *      but are not always present).
1860  */
1861 enum event_command_flags {
1862         EVENT_CMD_FL_POST_TRIGGER       = 1,
1863         EVENT_CMD_FL_NEEDS_REC          = 2,
1864 };
1865 
1866 static inline bool event_command_post_trigger(struct event_command *cmd_ops)
1867 {
1868         return cmd_ops->flags & EVENT_CMD_FL_POST_TRIGGER;
1869 }
1870 
1871 static inline bool event_command_needs_rec(struct event_command *cmd_ops)
1872 {
1873         return cmd_ops->flags & EVENT_CMD_FL_NEEDS_REC;
1874 }
1875 
1876 extern int trace_event_enable_disable(struct trace_event_file *file,
1877                                       int enable, int soft_disable);
1878 extern int tracing_alloc_snapshot(void);
1879 extern void tracing_snapshot_cond(struct trace_array *tr, void *cond_data);
1880 extern int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, cond_update_fn_t update);
1881 
1882 extern int tracing_snapshot_cond_disable(struct trace_array *tr);
1883 extern void *tracing_cond_snapshot_data(struct trace_array *tr);
1884 
1885 extern const char *__start___trace_bprintk_fmt[];
1886 extern const char *__stop___trace_bprintk_fmt[];
1887 
1888 extern const char *__start___tracepoint_str[];
1889 extern const char *__stop___tracepoint_str[];
1890 
1891 void trace_printk_control(bool enabled);
1892 void trace_printk_init_buffers(void);
1893 void trace_printk_start_comm(void);
1894 int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set);
1895 int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled);
1896 
1897 #define MAX_EVENT_NAME_LEN      64
1898 
1899 extern int trace_run_command(const char *buf, int (*createfn)(int, char**));
1900 extern ssize_t trace_parse_run_command(struct file *file,
1901                 const char __user *buffer, size_t count, loff_t *ppos,
1902                 int (*createfn)(int, char**));
1903 
1904 extern unsigned int err_pos(char *cmd, const char *str);
1905 extern void tracing_log_err(struct trace_array *tr,
1906                             const char *loc, const char *cmd,
1907                             const char **errs, u8 type, u8 pos);
1908 
1909 /*
1910  * Normal trace_printk() and friends allocates special buffers
1911  * to do the manipulation, as well as saves the print formats
1912  * into sections to display. But the trace infrastructure wants
1913  * to use these without the added overhead at the price of being
1914  * a bit slower (used mainly for warnings, where we don't care
1915  * about performance). The internal_trace_puts() is for such
1916  * a purpose.
1917  */
1918 #define internal_trace_puts(str) __trace_puts(_THIS_IP_, str, strlen(str))
1919 
1920 #undef FTRACE_ENTRY
1921 #define FTRACE_ENTRY(call, struct_name, id, tstruct, print, filter)     \
1922         extern struct trace_event_call                                  \
1923         __aligned(4) event_##call;
1924 #undef FTRACE_ENTRY_DUP
1925 #define FTRACE_ENTRY_DUP(call, struct_name, id, tstruct, print, filter) \
1926         FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print), \
1927                      filter)
1928 #undef FTRACE_ENTRY_PACKED
1929 #define FTRACE_ENTRY_PACKED(call, struct_name, id, tstruct, print, filter) \
1930         FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print), \
1931                      filter)
1932 
1933 #include "trace_entries.h"
1934 
1935 #if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_FUNCTION_TRACER)
1936 int perf_ftrace_event_register(struct trace_event_call *call,
1937                                enum trace_reg type, void *data);
1938 #else
1939 #define perf_ftrace_event_register NULL
1940 #endif
1941 
1942 #ifdef CONFIG_FTRACE_SYSCALLS
1943 void init_ftrace_syscalls(void);
1944 const char *get_syscall_name(int syscall);
1945 #else
1946 static inline void init_ftrace_syscalls(void) { }
1947 static inline const char *get_syscall_name(int syscall)
1948 {
1949         return NULL;
1950 }
1951 #endif
1952 
1953 #ifdef CONFIG_EVENT_TRACING
1954 void trace_event_init(void);
1955 void trace_event_eval_update(struct trace_eval_map **map, int len);
1956 #else
1957 static inline void __init trace_event_init(void) { }
1958 static inline void trace_event_eval_update(struct trace_eval_map **map, int len) { }
1959 #endif
1960 
1961 #ifdef CONFIG_TRACER_SNAPSHOT
1962 void tracing_snapshot_instance(struct trace_array *tr);
1963 int tracing_alloc_snapshot_instance(struct trace_array *tr);
1964 #else
1965 static inline void tracing_snapshot_instance(struct trace_array *tr) { }
1966 static inline int tracing_alloc_snapshot_instance(struct trace_array *tr)
1967 {
1968         return 0;
1969 }
1970 #endif
1971 
1972 #ifdef CONFIG_PREEMPT_TRACER
1973 void tracer_preempt_on(unsigned long a0, unsigned long a1);
1974 void tracer_preempt_off(unsigned long a0, unsigned long a1);
1975 #else
1976 static inline void tracer_preempt_on(unsigned long a0, unsigned long a1) { }
1977 static inline void tracer_preempt_off(unsigned long a0, unsigned long a1) { }
1978 #endif
1979 #ifdef CONFIG_IRQSOFF_TRACER
1980 void tracer_hardirqs_on(unsigned long a0, unsigned long a1);
1981 void tracer_hardirqs_off(unsigned long a0, unsigned long a1);
1982 #else
1983 static inline void tracer_hardirqs_on(unsigned long a0, unsigned long a1) { }
1984 static inline void tracer_hardirqs_off(unsigned long a0, unsigned long a1) { }
1985 #endif
1986 
1987 extern struct trace_iterator *tracepoint_print_iter;
1988 
1989 /*
1990  * Reset the state of the trace_iterator so that it can read consumed data.
1991  * Normally, the trace_iterator is used for reading the data when it is not
1992  * consumed, and must retain state.
1993  */
1994 static __always_inline void trace_iterator_reset(struct trace_iterator *iter)
1995 {
1996         const size_t offset = offsetof(struct trace_iterator, seq);
1997 
1998         /*
1999          * Keep gcc from complaining about overwriting more than just one
2000          * member in the structure.
2001          */
2002         memset((char *)iter + offset, 0, sizeof(struct trace_iterator) - offset);
2003 
2004         iter->pos = -1;
2005 }
2006 
2007 #endif /* _LINUX_KERNEL_TRACE_H */
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root/kernel/trace/trace.h

INCLUDED FROM

DEFINITIONS
