1#ifndef _LINUX_KPROBES_H 2#define _LINUX_KPROBES_H 3/* 4 * Kernel Probes (KProbes) 5 * include/linux/kprobes.h 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 20 * 21 * Copyright (C) IBM Corporation, 2002, 2004 22 * 23 * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel 24 * Probes initial implementation ( includes suggestions from 25 * Rusty Russell). 26 * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes 27 * interface to access function arguments. 28 * 2005-May Hien Nguyen <hien@us.ibm.com> and Jim Keniston 29 * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi 30 * <prasanna@in.ibm.com> added function-return probes. 31 */ 32#include <linux/compiler.h> /* for __kprobes */ 33#include <linux/linkage.h> 34#include <linux/list.h> 35#include <linux/notifier.h> 36#include <linux/smp.h> 37#include <linux/bug.h> 38#include <linux/percpu.h> 39#include <linux/spinlock.h> 40#include <linux/rcupdate.h> 41#include <linux/mutex.h> 42#include <linux/ftrace.h> 43 44#ifdef CONFIG_KPROBES 45#include <asm/kprobes.h> 46 47/* kprobe_status settings */ 48#define KPROBE_HIT_ACTIVE 0x00000001 49#define KPROBE_HIT_SS 0x00000002 50#define KPROBE_REENTER 0x00000004 51#define KPROBE_HIT_SSDONE 0x00000008 52 53#else /* CONFIG_KPROBES */ 54typedef int kprobe_opcode_t; 55struct arch_specific_insn { 56 int dummy; 57}; 58#endif /* CONFIG_KPROBES */ 59 60struct kprobe; 61struct pt_regs; 62struct kretprobe; 63struct kretprobe_instance; 64typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *); 65typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *); 66typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *, 67 unsigned long flags); 68typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *, 69 int trapnr); 70typedef int (*kretprobe_handler_t) (struct kretprobe_instance *, 71 struct pt_regs *); 72 73struct kprobe { 74 struct hlist_node hlist; 75 76 /* list of kprobes for multi-handler support */ 77 struct list_head list; 78 79 /*count the number of times this probe was temporarily disarmed */ 80 unsigned long nmissed; 81 82 /* location of the probe point */ 83 kprobe_opcode_t *addr; 84 85 /* Allow user to indicate symbol name of the probe point */ 86 const char *symbol_name; 87 88 /* Offset into the symbol */ 89 unsigned int offset; 90 91 /* Called before addr is executed. */ 92 kprobe_pre_handler_t pre_handler; 93 94 /* Called after addr is executed, unless... */ 95 kprobe_post_handler_t post_handler; 96 97 /* 98 * ... called if executing addr causes a fault (eg. page fault). 99 * Return 1 if it handled fault, otherwise kernel will see it. 100 */ 101 kprobe_fault_handler_t fault_handler; 102 103 /* 104 * ... called if breakpoint trap occurs in probe handler. 105 * Return 1 if it handled break, otherwise kernel will see it. 106 */ 107 kprobe_break_handler_t break_handler; 108 109 /* Saved opcode (which has been replaced with breakpoint) */ 110 kprobe_opcode_t opcode; 111 112 /* copy of the original instruction */ 113 struct arch_specific_insn ainsn; 114 115 /* 116 * Indicates various status flags. 117 * Protected by kprobe_mutex after this kprobe is registered. 118 */ 119 u32 flags; 120}; 121 122/* Kprobe status flags */ 123#define KPROBE_FLAG_GONE 1 /* breakpoint has already gone */ 124#define KPROBE_FLAG_DISABLED 2 /* probe is temporarily disabled */ 125#define KPROBE_FLAG_OPTIMIZED 4 /* 126 * probe is really optimized. 127 * NOTE: 128 * this flag is only for optimized_kprobe. 129 */ 130#define KPROBE_FLAG_FTRACE 8 /* probe is using ftrace */ 131 132/* Has this kprobe gone ? */ 133static inline int kprobe_gone(struct kprobe *p) 134{ 135 return p->flags & KPROBE_FLAG_GONE; 136} 137 138/* Is this kprobe disabled ? */ 139static inline int kprobe_disabled(struct kprobe *p) 140{ 141 return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE); 142} 143 144/* Is this kprobe really running optimized path ? */ 145static inline int kprobe_optimized(struct kprobe *p) 146{ 147 return p->flags & KPROBE_FLAG_OPTIMIZED; 148} 149 150/* Is this kprobe uses ftrace ? */ 151static inline int kprobe_ftrace(struct kprobe *p) 152{ 153 return p->flags & KPROBE_FLAG_FTRACE; 154} 155 156/* 157 * Special probe type that uses setjmp-longjmp type tricks to resume 158 * execution at a specified entry with a matching prototype corresponding 159 * to the probed function - a trick to enable arguments to become 160 * accessible seamlessly by probe handling logic. 161 * Note: 162 * Because of the way compilers allocate stack space for local variables 163 * etc upfront, regardless of sub-scopes within a function, this mirroring 164 * principle currently works only for probes placed on function entry points. 165 */ 166struct jprobe { 167 struct kprobe kp; 168 void *entry; /* probe handling code to jump to */ 169}; 170 171/* For backward compatibility with old code using JPROBE_ENTRY() */ 172#define JPROBE_ENTRY(handler) (handler) 173 174/* 175 * Function-return probe - 176 * Note: 177 * User needs to provide a handler function, and initialize maxactive. 178 * maxactive - The maximum number of instances of the probed function that 179 * can be active concurrently. 180 * nmissed - tracks the number of times the probed function's return was 181 * ignored, due to maxactive being too low. 182 * 183 */ 184struct kretprobe { 185 struct kprobe kp; 186 kretprobe_handler_t handler; 187 kretprobe_handler_t entry_handler; 188 int maxactive; 189 int nmissed; 190 size_t data_size; 191 struct hlist_head free_instances; 192 raw_spinlock_t lock; 193}; 194 195struct kretprobe_instance { 196 struct hlist_node hlist; 197 struct kretprobe *rp; 198 kprobe_opcode_t *ret_addr; 199 struct task_struct *task; 200 char data[0]; 201}; 202 203struct kretprobe_blackpoint { 204 const char *name; 205 void *addr; 206}; 207 208struct kprobe_blacklist_entry { 209 struct list_head list; 210 unsigned long start_addr; 211 unsigned long end_addr; 212}; 213 214#ifdef CONFIG_KPROBES 215DECLARE_PER_CPU(struct kprobe *, current_kprobe); 216DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); 217 218/* 219 * For #ifdef avoidance: 220 */ 221static inline int kprobes_built_in(void) 222{ 223 return 1; 224} 225 226#ifdef CONFIG_KRETPROBES 227extern void arch_prepare_kretprobe(struct kretprobe_instance *ri, 228 struct pt_regs *regs); 229extern int arch_trampoline_kprobe(struct kprobe *p); 230#else /* CONFIG_KRETPROBES */ 231static inline void arch_prepare_kretprobe(struct kretprobe *rp, 232 struct pt_regs *regs) 233{ 234} 235static inline int arch_trampoline_kprobe(struct kprobe *p) 236{ 237 return 0; 238} 239#endif /* CONFIG_KRETPROBES */ 240 241extern struct kretprobe_blackpoint kretprobe_blacklist[]; 242 243static inline void kretprobe_assert(struct kretprobe_instance *ri, 244 unsigned long orig_ret_address, unsigned long trampoline_address) 245{ 246 if (!orig_ret_address || (orig_ret_address == trampoline_address)) { 247 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n", 248 ri->rp, ri->rp->kp.addr); 249 BUG(); 250 } 251} 252 253#ifdef CONFIG_KPROBES_SANITY_TEST 254extern int init_test_probes(void); 255#else 256static inline int init_test_probes(void) 257{ 258 return 0; 259} 260#endif /* CONFIG_KPROBES_SANITY_TEST */ 261 262extern int arch_prepare_kprobe(struct kprobe *p); 263extern void arch_arm_kprobe(struct kprobe *p); 264extern void arch_disarm_kprobe(struct kprobe *p); 265extern int arch_init_kprobes(void); 266extern void show_registers(struct pt_regs *regs); 267extern void kprobes_inc_nmissed_count(struct kprobe *p); 268extern bool arch_within_kprobe_blacklist(unsigned long addr); 269 270struct kprobe_insn_cache { 271 struct mutex mutex; 272 void *(*alloc)(void); /* allocate insn page */ 273 void (*free)(void *); /* free insn page */ 274 struct list_head pages; /* list of kprobe_insn_page */ 275 size_t insn_size; /* size of instruction slot */ 276 int nr_garbage; 277}; 278 279extern kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c); 280extern void __free_insn_slot(struct kprobe_insn_cache *c, 281 kprobe_opcode_t *slot, int dirty); 282 283#define DEFINE_INSN_CACHE_OPS(__name) \ 284extern struct kprobe_insn_cache kprobe_##__name##_slots; \ 285 \ 286static inline kprobe_opcode_t *get_##__name##_slot(void) \ 287{ \ 288 return __get_insn_slot(&kprobe_##__name##_slots); \ 289} \ 290 \ 291static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\ 292{ \ 293 __free_insn_slot(&kprobe_##__name##_slots, slot, dirty); \ 294} \ 295 296DEFINE_INSN_CACHE_OPS(insn); 297 298#ifdef CONFIG_OPTPROBES 299/* 300 * Internal structure for direct jump optimized probe 301 */ 302struct optimized_kprobe { 303 struct kprobe kp; 304 struct list_head list; /* list for optimizing queue */ 305 struct arch_optimized_insn optinsn; 306}; 307 308/* Architecture dependent functions for direct jump optimization */ 309extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn); 310extern int arch_check_optimized_kprobe(struct optimized_kprobe *op); 311extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, 312 struct kprobe *orig); 313extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op); 314extern void arch_optimize_kprobes(struct list_head *oplist); 315extern void arch_unoptimize_kprobes(struct list_head *oplist, 316 struct list_head *done_list); 317extern void arch_unoptimize_kprobe(struct optimized_kprobe *op); 318extern int arch_within_optimized_kprobe(struct optimized_kprobe *op, 319 unsigned long addr); 320 321extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs); 322 323DEFINE_INSN_CACHE_OPS(optinsn); 324 325#ifdef CONFIG_SYSCTL 326extern int sysctl_kprobes_optimization; 327extern int proc_kprobes_optimization_handler(struct ctl_table *table, 328 int write, void __user *buffer, 329 size_t *length, loff_t *ppos); 330#endif 331 332#endif /* CONFIG_OPTPROBES */ 333#ifdef CONFIG_KPROBES_ON_FTRACE 334extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, 335 struct ftrace_ops *ops, struct pt_regs *regs); 336extern int arch_prepare_kprobe_ftrace(struct kprobe *p); 337#endif 338 339int arch_check_ftrace_location(struct kprobe *p); 340 341/* Get the kprobe at this addr (if any) - called with preemption disabled */ 342struct kprobe *get_kprobe(void *addr); 343void kretprobe_hash_lock(struct task_struct *tsk, 344 struct hlist_head **head, unsigned long *flags); 345void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags); 346struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk); 347 348/* kprobe_running() will just return the current_kprobe on this CPU */ 349static inline struct kprobe *kprobe_running(void) 350{ 351 return (__this_cpu_read(current_kprobe)); 352} 353 354static inline void reset_current_kprobe(void) 355{ 356 __this_cpu_write(current_kprobe, NULL); 357} 358 359static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void) 360{ 361 return this_cpu_ptr(&kprobe_ctlblk); 362} 363 364int register_kprobe(struct kprobe *p); 365void unregister_kprobe(struct kprobe *p); 366int register_kprobes(struct kprobe **kps, int num); 367void unregister_kprobes(struct kprobe **kps, int num); 368int setjmp_pre_handler(struct kprobe *, struct pt_regs *); 369int longjmp_break_handler(struct kprobe *, struct pt_regs *); 370int register_jprobe(struct jprobe *p); 371void unregister_jprobe(struct jprobe *p); 372int register_jprobes(struct jprobe **jps, int num); 373void unregister_jprobes(struct jprobe **jps, int num); 374void jprobe_return(void); 375unsigned long arch_deref_entry_point(void *); 376 377int register_kretprobe(struct kretprobe *rp); 378void unregister_kretprobe(struct kretprobe *rp); 379int register_kretprobes(struct kretprobe **rps, int num); 380void unregister_kretprobes(struct kretprobe **rps, int num); 381 382void kprobe_flush_task(struct task_struct *tk); 383void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head); 384 385int disable_kprobe(struct kprobe *kp); 386int enable_kprobe(struct kprobe *kp); 387 388void dump_kprobe(struct kprobe *kp); 389 390#else /* !CONFIG_KPROBES: */ 391 392static inline int kprobes_built_in(void) 393{ 394 return 0; 395} 396static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr) 397{ 398 return 0; 399} 400static inline struct kprobe *get_kprobe(void *addr) 401{ 402 return NULL; 403} 404static inline struct kprobe *kprobe_running(void) 405{ 406 return NULL; 407} 408static inline int register_kprobe(struct kprobe *p) 409{ 410 return -ENOSYS; 411} 412static inline int register_kprobes(struct kprobe **kps, int num) 413{ 414 return -ENOSYS; 415} 416static inline void unregister_kprobe(struct kprobe *p) 417{ 418} 419static inline void unregister_kprobes(struct kprobe **kps, int num) 420{ 421} 422static inline int register_jprobe(struct jprobe *p) 423{ 424 return -ENOSYS; 425} 426static inline int register_jprobes(struct jprobe **jps, int num) 427{ 428 return -ENOSYS; 429} 430static inline void unregister_jprobe(struct jprobe *p) 431{ 432} 433static inline void unregister_jprobes(struct jprobe **jps, int num) 434{ 435} 436static inline void jprobe_return(void) 437{ 438} 439static inline int register_kretprobe(struct kretprobe *rp) 440{ 441 return -ENOSYS; 442} 443static inline int register_kretprobes(struct kretprobe **rps, int num) 444{ 445 return -ENOSYS; 446} 447static inline void unregister_kretprobe(struct kretprobe *rp) 448{ 449} 450static inline void unregister_kretprobes(struct kretprobe **rps, int num) 451{ 452} 453static inline void kprobe_flush_task(struct task_struct *tk) 454{ 455} 456static inline int disable_kprobe(struct kprobe *kp) 457{ 458 return -ENOSYS; 459} 460static inline int enable_kprobe(struct kprobe *kp) 461{ 462 return -ENOSYS; 463} 464#endif /* CONFIG_KPROBES */ 465static inline int disable_kretprobe(struct kretprobe *rp) 466{ 467 return disable_kprobe(&rp->kp); 468} 469static inline int enable_kretprobe(struct kretprobe *rp) 470{ 471 return enable_kprobe(&rp->kp); 472} 473static inline int disable_jprobe(struct jprobe *jp) 474{ 475 return disable_kprobe(&jp->kp); 476} 477static inline int enable_jprobe(struct jprobe *jp) 478{ 479 return enable_kprobe(&jp->kp); 480} 481 482#ifdef CONFIG_KPROBES 483/* 484 * Blacklist ganerating macro. Specify functions which is not probed 485 * by using this macro. 486 */ 487#define __NOKPROBE_SYMBOL(fname) \ 488static unsigned long __used \ 489 __attribute__((section("_kprobe_blacklist"))) \ 490 _kbl_addr_##fname = (unsigned long)fname; 491#define NOKPROBE_SYMBOL(fname) __NOKPROBE_SYMBOL(fname) 492#else 493#define NOKPROBE_SYMBOL(fname) 494#endif 495 496#endif /* _LINUX_KPROBES_H */ 497