include/linux/kprobes.h

   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>
  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 #include <asm/kprobes.h>
  44
  45 #ifdef CONFIG_KPROBES
  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 */
  54 #include <asm-generic/kprobes.h>
  55 typedef int kprobe_opcode_t;
  56 struct arch_specific_insn {
  57         int dummy;
  58 };
  59 #endif /* CONFIG_KPROBES */
  60
  61 struct kprobe;
  62 struct pt_regs;
  63 struct kretprobe;
  64 struct kretprobe_instance;
  65 typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
  66 typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *);
  67 typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
  68                                        unsigned long flags);
  69 typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
  70                                        int trapnr);
  71 typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
  72                                     struct pt_regs *);
  73
  74 struct kprobe {
  75         struct hlist_node hlist;
  76
  77         /* list of kprobes for multi-handler support */
  78         struct list_head list;
  79
  80         /*count the number of times this probe was temporarily disarmed */
  81         unsigned long nmissed;
  82
  83         /* location of the probe point */
  84         kprobe_opcode_t *addr;
  85
  86         /* Allow user to indicate symbol name of the probe point */
  87         const char *symbol_name;
  88
  89         /* Offset into the symbol */
  90         unsigned int offset;
  91
  92         /* Called before addr is executed. */
  93         kprobe_pre_handler_t pre_handler;
  94
  95         /* Called after addr is executed, unless... */
  96         kprobe_post_handler_t post_handler;
  97
  98         /*
  99          * ... called if executing addr causes a fault (eg. page fault).
 100          * Return 1 if it handled fault, otherwise kernel will see it.
 101          */
 102         kprobe_fault_handler_t fault_handler;
 103
 104         /*
 105          * ... called if breakpoint trap occurs in probe handler.
 106          * Return 1 if it handled break, otherwise kernel will see it.
 107          */
 108         kprobe_break_handler_t break_handler;
 109
 110         /* Saved opcode (which has been replaced with breakpoint) */
 111         kprobe_opcode_t opcode;
 112
 113         /* copy of the original instruction */
 114         struct arch_specific_insn ainsn;
 115
 116         /*
 117          * Indicates various status flags.
 118          * Protected by kprobe_mutex after this kprobe is registered.
 119          */
 120         u32 flags;
 121 };
 122
 123 /* Kprobe status flags */
 124 #define KPROBE_FLAG_GONE        1 /* breakpoint has already gone */
 125 #define KPROBE_FLAG_DISABLED    2 /* probe is temporarily disabled */
 126 #define KPROBE_FLAG_OPTIMIZED   4 /*
 127                                    * probe is really optimized.
 128                                    * NOTE:
 129                                    * this flag is only for optimized_kprobe.
 130                                    */
 131 #define KPROBE_FLAG_FTRACE      8 /* probe is using ftrace */
 132
 133 /* Has this kprobe gone ? */
 134 static inline int kprobe_gone(struct kprobe *p)
 135 {
 136         return p->flags & KPROBE_FLAG_GONE;
 137 }
 138
 139 /* Is this kprobe disabled ? */
 140 static inline int kprobe_disabled(struct kprobe *p)
 141 {
 142         return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
 143 }
 144
 145 /* Is this kprobe really running optimized path ? */
 146 static inline int kprobe_optimized(struct kprobe *p)
 147 {
 148         return p->flags & KPROBE_FLAG_OPTIMIZED;
 149 }
 150
 151 /* Is this kprobe uses ftrace ? */
 152 static inline int kprobe_ftrace(struct kprobe *p)
 153 {
 154         return p->flags & KPROBE_FLAG_FTRACE;
 155 }
 156
 157 /*
 158  * Special probe type that uses setjmp-longjmp type tricks to resume
 159  * execution at a specified entry with a matching prototype corresponding
 160  * to the probed function - a trick to enable arguments to become
 161  * accessible seamlessly by probe handling logic.
 162  * Note:
 163  * Because of the way compilers allocate stack space for local variables
 164  * etc upfront, regardless of sub-scopes within a function, this mirroring
 165  * principle currently works only for probes placed on function entry points.
 166  */
 167 struct jprobe {
 168         struct kprobe kp;
 169         void *entry;    /* probe handling code to jump to */
 170 };
 171
 172 /* For backward compatibility with old code using JPROBE_ENTRY() */
 173 #define JPROBE_ENTRY(handler)   (handler)
 174
 175 /*
 176  * Function-return probe -
 177  * Note:
 178  * User needs to provide a handler function, and initialize maxactive.
 179  * maxactive - The maximum number of instances of the probed function that
 180  * can be active concurrently.
 181  * nmissed - tracks the number of times the probed function's return was
 182  * ignored, due to maxactive being too low.
 183  *
 184  */
 185 struct kretprobe {
 186         struct kprobe kp;
 187         kretprobe_handler_t handler;
 188         kretprobe_handler_t entry_handler;
 189         int maxactive;
 190         int nmissed;
 191         size_t data_size;
 192         struct hlist_head free_instances;
 193         raw_spinlock_t lock;
 194 };
 195
 196 struct kretprobe_instance {
 197         struct hlist_node hlist;
 198         struct kretprobe *rp;
 199         kprobe_opcode_t *ret_addr;
 200         struct task_struct *task;
 201         char data[0];
 202 };
 203
 204 struct kretprobe_blackpoint {
 205         const char *name;
 206         void *addr;
 207 };
 208
 209 struct kprobe_blacklist_entry {
 210         struct list_head list;
 211         unsigned long start_addr;
 212         unsigned long end_addr;
 213 };
 214
 215 #ifdef CONFIG_KPROBES
 216 DECLARE_PER_CPU(struct kprobe *, current_kprobe);
 217 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 218
 219 /*
 220  * For #ifdef avoidance:
 221  */
 222 static inline int kprobes_built_in(void)
 223 {
 224         return 1;
 225 }
 226
 227 #ifdef CONFIG_KRETPROBES
 228 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
 229                                    struct pt_regs *regs);
 230 extern int arch_trampoline_kprobe(struct kprobe *p);
 231 #else /* CONFIG_KRETPROBES */
 232 static inline void arch_prepare_kretprobe(struct kretprobe *rp,
 233                                         struct pt_regs *regs)
 234 {
 235 }
 236 static inline int arch_trampoline_kprobe(struct kprobe *p)
 237 {
 238         return 0;
 239 }
 240 #endif /* CONFIG_KRETPROBES */
 241
 242 extern struct kretprobe_blackpoint kretprobe_blacklist[];
 243
 244 static inline void kretprobe_assert(struct kretprobe_instance *ri,
 245         unsigned long orig_ret_address, unsigned long trampoline_address)
 246 {
 247         if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
 248                 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
 249                                 ri->rp, ri->rp->kp.addr);
 250                 BUG();
 251         }
 252 }
 253
 254 #ifdef CONFIG_KPROBES_SANITY_TEST
 255 extern int init_test_probes(void);
 256 #else
 257 static inline int init_test_probes(void)
 258 {
 259         return 0;
 260 }
 261 #endif /* CONFIG_KPROBES_SANITY_TEST */
 262
 263 extern int arch_prepare_kprobe(struct kprobe *p);
 264 extern void arch_arm_kprobe(struct kprobe *p);
 265 extern void arch_disarm_kprobe(struct kprobe *p);
 266 extern int arch_init_kprobes(void);
 267 extern void show_registers(struct pt_regs *regs);
 268 extern void kprobes_inc_nmissed_count(struct kprobe *p);
 269 extern bool arch_within_kprobe_blacklist(unsigned long addr);
 270
 271 extern bool within_kprobe_blacklist(unsigned long addr);
 272
 273 struct kprobe_insn_cache {
 274         struct mutex mutex;
 275         void *(*alloc)(void);   /* allocate insn page */
 276         void (*free)(void *);   /* free insn page */
 277         struct list_head pages; /* list of kprobe_insn_page */
 278         size_t insn_size;       /* size of instruction slot */
 279         int nr_garbage;
 280 };
 281
 282 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
 283 extern kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c);
 284 extern void __free_insn_slot(struct kprobe_insn_cache *c,
 285                              kprobe_opcode_t *slot, int dirty);
 286 /* sleep-less address checking routine  */
 287 extern bool __is_insn_slot_addr(struct kprobe_insn_cache *c,
 288                                 unsigned long addr);
 289
 290 #define DEFINE_INSN_CACHE_OPS(__name)                                   \
 291 extern struct kprobe_insn_cache kprobe_##__name##_slots;                \
 292                                                                         \
 293 static inline kprobe_opcode_t *get_##__name##_slot(void)                \
 294 {                                                                       \
 295         return __get_insn_slot(&kprobe_##__name##_slots);               \
 296 }                                                                       \
 297                                                                         \
 298 static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\
 299 {                                                                       \
 300         __free_insn_slot(&kprobe_##__name##_slots, slot, dirty);        \
 301 }                                                                       \
 302                                                                         \
 303 static inline bool is_kprobe_##__name##_slot(unsigned long addr)        \
 304 {                                                                       \
 305         return __is_insn_slot_addr(&kprobe_##__name##_slots, addr);     \
 306 }
 307 #else /* __ARCH_WANT_KPROBES_INSN_SLOT */
 308 #define DEFINE_INSN_CACHE_OPS(__name)                                   \
 309 static inline bool is_kprobe_##__name##_slot(unsigned long addr)        \
 310 {                                                                       \
 311         return 0;                                                       \
 312 }
 313 #endif
 314
 315 DEFINE_INSN_CACHE_OPS(insn);
 316
 317 #ifdef CONFIG_OPTPROBES
 318 /*
 319  * Internal structure for direct jump optimized probe
 320  */
 321 struct optimized_kprobe {
 322         struct kprobe kp;
 323         struct list_head list;  /* list for optimizing queue */
 324         struct arch_optimized_insn optinsn;
 325 };
 326
 327 /* Architecture dependent functions for direct jump optimization */
 328 extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
 329 extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
 330 extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op,
 331                                          struct kprobe *orig);
 332 extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
 333 extern void arch_optimize_kprobes(struct list_head *oplist);
 334 extern void arch_unoptimize_kprobes(struct list_head *oplist,
 335                                     struct list_head *done_list);
 336 extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
 337 extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
 338                                         unsigned long addr);
 339
 340 extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
 341
 342 DEFINE_INSN_CACHE_OPS(optinsn);
 343
 344 #ifdef CONFIG_SYSCTL
 345 extern int sysctl_kprobes_optimization;
 346 extern int proc_kprobes_optimization_handler(struct ctl_table *table,
 347                                              int write, void __user *buffer,
 348                                              size_t *length, loff_t *ppos);
 349 #endif
 350 #endif /* CONFIG_OPTPROBES */
 351 #ifdef CONFIG_KPROBES_ON_FTRACE
 352 extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
 353                                   struct ftrace_ops *ops, struct pt_regs *regs);
 354 extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
 355 #endif
 356
 357 int arch_check_ftrace_location(struct kprobe *p);
 358
 359 /* Get the kprobe at this addr (if any) - called with preemption disabled */
 360 struct kprobe *get_kprobe(void *addr);
 361 void kretprobe_hash_lock(struct task_struct *tsk,
 362                          struct hlist_head **head, unsigned long *flags);
 363 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
 364 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
 365
 366 /* kprobe_running() will just return the current_kprobe on this CPU */
 367 static inline struct kprobe *kprobe_running(void)
 368 {
 369         return (__this_cpu_read(current_kprobe));
 370 }
 371
 372 static inline void reset_current_kprobe(void)
 373 {
 374         __this_cpu_write(current_kprobe, NULL);
 375 }
 376
 377 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
 378 {
 379         return this_cpu_ptr(&kprobe_ctlblk);
 380 }
 381
 382 int register_kprobe(struct kprobe *p);
 383 void unregister_kprobe(struct kprobe *p);
 384 int register_kprobes(struct kprobe **kps, int num);
 385 void unregister_kprobes(struct kprobe **kps, int num);
 386 int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
 387 int longjmp_break_handler(struct kprobe *, struct pt_regs *);
 388 int register_jprobe(struct jprobe *p);
 389 void unregister_jprobe(struct jprobe *p);
 390 int register_jprobes(struct jprobe **jps, int num);
 391 void unregister_jprobes(struct jprobe **jps, int num);
 392 void jprobe_return(void);
 393 unsigned long arch_deref_entry_point(void *);
 394
 395 int register_kretprobe(struct kretprobe *rp);
 396 void unregister_kretprobe(struct kretprobe *rp);
 397 int register_kretprobes(struct kretprobe **rps, int num);
 398 void unregister_kretprobes(struct kretprobe **rps, int num);
 399
 400 void kprobe_flush_task(struct task_struct *tk);
 401 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
 402
 403 int disable_kprobe(struct kprobe *kp);
 404 int enable_kprobe(struct kprobe *kp);
 405
 406 void dump_kprobe(struct kprobe *kp);
 407
 408 #else /* !CONFIG_KPROBES: */
 409
 410 static inline int kprobes_built_in(void)
 411 {
 412         return 0;
 413 }
 414 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 415 {
 416         return 0;
 417 }
 418 static inline struct kprobe *get_kprobe(void *addr)
 419 {
 420         return NULL;
 421 }
 422 static inline struct kprobe *kprobe_running(void)
 423 {
 424         return NULL;
 425 }
 426 static inline int register_kprobe(struct kprobe *p)
 427 {
 428         return -ENOSYS;
 429 }
 430 static inline int register_kprobes(struct kprobe **kps, int num)
 431 {
 432         return -ENOSYS;
 433 }
 434 static inline void unregister_kprobe(struct kprobe *p)
 435 {
 436 }
 437 static inline void unregister_kprobes(struct kprobe **kps, int num)
 438 {
 439 }
 440 static inline int register_jprobe(struct jprobe *p)
 441 {
 442         return -ENOSYS;
 443 }
 444 static inline int register_jprobes(struct jprobe **jps, int num)
 445 {
 446         return -ENOSYS;
 447 }
 448 static inline void unregister_jprobe(struct jprobe *p)
 449 {
 450 }
 451 static inline void unregister_jprobes(struct jprobe **jps, int num)
 452 {
 453 }
 454 static inline void jprobe_return(void)
 455 {
 456 }
 457 static inline int register_kretprobe(struct kretprobe *rp)
 458 {
 459         return -ENOSYS;
 460 }
 461 static inline int register_kretprobes(struct kretprobe **rps, int num)
 462 {
 463         return -ENOSYS;
 464 }
 465 static inline void unregister_kretprobe(struct kretprobe *rp)
 466 {
 467 }
 468 static inline void unregister_kretprobes(struct kretprobe **rps, int num)
 469 {
 470 }
 471 static inline void kprobe_flush_task(struct task_struct *tk)
 472 {
 473 }
 474 static inline int disable_kprobe(struct kprobe *kp)
 475 {
 476         return -ENOSYS;
 477 }
 478 static inline int enable_kprobe(struct kprobe *kp)
 479 {
 480         return -ENOSYS;
 481 }
 482 #endif /* CONFIG_KPROBES */
 483 static inline int disable_kretprobe(struct kretprobe *rp)
 484 {
 485         return disable_kprobe(&rp->kp);
 486 }
 487 static inline int enable_kretprobe(struct kretprobe *rp)
 488 {
 489         return enable_kprobe(&rp->kp);
 490 }
 491 static inline int disable_jprobe(struct jprobe *jp)
 492 {
 493         return disable_kprobe(&jp->kp);
 494 }
 495 static inline int enable_jprobe(struct jprobe *jp)
 496 {
 497         return enable_kprobe(&jp->kp);
 498 }
 499
 500 #ifndef CONFIG_KPROBES
 501 static inline bool is_kprobe_insn_slot(unsigned long addr)
 502 {
 503         return false;
 504 }
 505 #endif
 506 #ifndef CONFIG_OPTPROBES
 507 static inline bool is_kprobe_optinsn_slot(unsigned long addr)
 508 {
 509         return false;
 510 }
 511 #endif
 512
 513 #endif /* _LINUX_KPROBES_H */