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>     /* 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 */
  54 typedef int kprobe_opcode_t;
  55 struct arch_specific_insn {
  56         int dummy;
  57 };
  58 #endif /* CONFIG_KPROBES */
  59
  60 struct kprobe;
  61 struct pt_regs;
  62 struct kretprobe;
  63 struct kretprobe_instance;
  64 typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
  65 typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *);
  66 typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
  67                                        unsigned long flags);
  68 typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
  69                                        int trapnr);
  70 typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
  71                                     struct pt_regs *);
  72
  73 struct 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 ? */
 133 static inline int kprobe_gone(struct kprobe *p)
 134 {
 135         return p->flags & KPROBE_FLAG_GONE;
 136 }
 137
 138 /* Is this kprobe disabled ? */
 139 static 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 ? */
 145 static inline int kprobe_optimized(struct kprobe *p)
 146 {
 147         return p->flags & KPROBE_FLAG_OPTIMIZED;
 148 }
 149
 150 /* Is this kprobe uses ftrace ? */
 151 static 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  */
 166 struct 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  */
 184 struct 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
 195 struct 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
 203 struct kretprobe_blackpoint {
 204         const char *name;
 205         void *addr;
 206 };
 207
 208 struct kprobe_blacklist_entry {
 209         struct list_head list;
 210         unsigned long start_addr;
 211         unsigned long end_addr;
 212 };
 213
 214 #ifdef CONFIG_KPROBES
 215 DECLARE_PER_CPU(struct kprobe *, current_kprobe);
 216 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 217
 218 /*
 219  * For #ifdef avoidance:
 220  */
 221 static inline int kprobes_built_in(void)
 222 {
 223         return 1;
 224 }
 225
 226 #ifdef CONFIG_KRETPROBES
 227 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
 228                                    struct pt_regs *regs);
 229 extern int arch_trampoline_kprobe(struct kprobe *p);
 230 #else /* CONFIG_KRETPROBES */
 231 static inline void arch_prepare_kretprobe(struct kretprobe *rp,
 232                                         struct pt_regs *regs)
 233 {
 234 }
 235 static inline int arch_trampoline_kprobe(struct kprobe *p)
 236 {
 237         return 0;
 238 }
 239 #endif /* CONFIG_KRETPROBES */
 240
 241 extern struct kretprobe_blackpoint kretprobe_blacklist[];
 242
 243 static 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
 254 extern int init_test_probes(void);
 255 #else
 256 static inline int init_test_probes(void)
 257 {
 258         return 0;
 259 }
 260 #endif /* CONFIG_KPROBES_SANITY_TEST */
 261
 262 extern int arch_prepare_kprobe(struct kprobe *p);
 263 extern void arch_arm_kprobe(struct kprobe *p);
 264 extern void arch_disarm_kprobe(struct kprobe *p);
 265 extern int arch_init_kprobes(void);
 266 extern void show_registers(struct pt_regs *regs);
 267 extern void kprobes_inc_nmissed_count(struct kprobe *p);
 268 extern bool arch_within_kprobe_blacklist(unsigned long addr);
 269
 270 struct 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
 279 extern kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c);
 280 extern void __free_insn_slot(struct kprobe_insn_cache *c,
 281                              kprobe_opcode_t *slot, int dirty);
 282
 283 #define DEFINE_INSN_CACHE_OPS(__name)                                   \
 284 extern struct kprobe_insn_cache kprobe_##__name##_slots;                \
 285                                                                         \
 286 static inline kprobe_opcode_t *get_##__name##_slot(void)                \
 287 {                                                                       \
 288         return __get_insn_slot(&kprobe_##__name##_slots);               \
 289 }                                                                       \
 290                                                                         \
 291 static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\
 292 {                                                                       \
 293         __free_insn_slot(&kprobe_##__name##_slots, slot, dirty);        \
 294 }                                                                       \
 295
 296 DEFINE_INSN_CACHE_OPS(insn);
 297
 298 #ifdef CONFIG_OPTPROBES
 299 /*
 300  * Internal structure for direct jump optimized probe
 301  */
 302 struct 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 */
 309 extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
 310 extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
 311 extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op,
 312                                          struct kprobe *orig);
 313 extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
 314 extern void arch_optimize_kprobes(struct list_head *oplist);
 315 extern void arch_unoptimize_kprobes(struct list_head *oplist,
 316                                     struct list_head *done_list);
 317 extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
 318 extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
 319                                         unsigned long addr);
 320
 321 extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
 322
 323 DEFINE_INSN_CACHE_OPS(optinsn);
 324
 325 #ifdef CONFIG_SYSCTL
 326 extern int sysctl_kprobes_optimization;
 327 extern 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
 334 extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
 335                                   struct ftrace_ops *ops, struct pt_regs *regs);
 336 extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
 337 #endif
 338
 339 int arch_check_ftrace_location(struct kprobe *p);
 340
 341 /* Get the kprobe at this addr (if any) - called with preemption disabled */
 342 struct kprobe *get_kprobe(void *addr);
 343 void kretprobe_hash_lock(struct task_struct *tsk,
 344                          struct hlist_head **head, unsigned long *flags);
 345 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
 346 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
 347
 348 /* kprobe_running() will just return the current_kprobe on this CPU */
 349 static inline struct kprobe *kprobe_running(void)
 350 {
 351         return (__this_cpu_read(current_kprobe));
 352 }
 353
 354 static inline void reset_current_kprobe(void)
 355 {
 356         __this_cpu_write(current_kprobe, NULL);
 357 }
 358
 359 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
 360 {
 361         return this_cpu_ptr(&kprobe_ctlblk);
 362 }
 363
 364 int register_kprobe(struct kprobe *p);
 365 void unregister_kprobe(struct kprobe *p);
 366 int register_kprobes(struct kprobe **kps, int num);
 367 void unregister_kprobes(struct kprobe **kps, int num);
 368 int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
 369 int longjmp_break_handler(struct kprobe *, struct pt_regs *);
 370 int register_jprobe(struct jprobe *p);
 371 void unregister_jprobe(struct jprobe *p);
 372 int register_jprobes(struct jprobe **jps, int num);
 373 void unregister_jprobes(struct jprobe **jps, int num);
 374 void jprobe_return(void);
 375 unsigned long arch_deref_entry_point(void *);
 376
 377 int register_kretprobe(struct kretprobe *rp);
 378 void unregister_kretprobe(struct kretprobe *rp);
 379 int register_kretprobes(struct kretprobe **rps, int num);
 380 void unregister_kretprobes(struct kretprobe **rps, int num);
 381
 382 void kprobe_flush_task(struct task_struct *tk);
 383 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
 384
 385 int disable_kprobe(struct kprobe *kp);
 386 int enable_kprobe(struct kprobe *kp);
 387
 388 void dump_kprobe(struct kprobe *kp);
 389
 390 #else /* !CONFIG_KPROBES: */
 391
 392 static inline int kprobes_built_in(void)
 393 {
 394         return 0;
 395 }
 396 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 397 {
 398         return 0;
 399 }
 400 static inline struct kprobe *get_kprobe(void *addr)
 401 {
 402         return NULL;
 403 }
 404 static inline struct kprobe *kprobe_running(void)
 405 {
 406         return NULL;
 407 }
 408 static inline int register_kprobe(struct kprobe *p)
 409 {
 410         return -ENOSYS;
 411 }
 412 static inline int register_kprobes(struct kprobe **kps, int num)
 413 {
 414         return -ENOSYS;
 415 }
 416 static inline void unregister_kprobe(struct kprobe *p)
 417 {
 418 }
 419 static inline void unregister_kprobes(struct kprobe **kps, int num)
 420 {
 421 }
 422 static inline int register_jprobe(struct jprobe *p)
 423 {
 424         return -ENOSYS;
 425 }
 426 static inline int register_jprobes(struct jprobe **jps, int num)
 427 {
 428         return -ENOSYS;
 429 }
 430 static inline void unregister_jprobe(struct jprobe *p)
 431 {
 432 }
 433 static inline void unregister_jprobes(struct jprobe **jps, int num)
 434 {
 435 }
 436 static inline void jprobe_return(void)
 437 {
 438 }
 439 static inline int register_kretprobe(struct kretprobe *rp)
 440 {
 441         return -ENOSYS;
 442 }
 443 static inline int register_kretprobes(struct kretprobe **rps, int num)
 444 {
 445         return -ENOSYS;
 446 }
 447 static inline void unregister_kretprobe(struct kretprobe *rp)
 448 {
 449 }
 450 static inline void unregister_kretprobes(struct kretprobe **rps, int num)
 451 {
 452 }
 453 static inline void kprobe_flush_task(struct task_struct *tk)
 454 {
 455 }
 456 static inline int disable_kprobe(struct kprobe *kp)
 457 {
 458         return -ENOSYS;
 459 }
 460 static inline int enable_kprobe(struct kprobe *kp)
 461 {
 462         return -ENOSYS;
 463 }
 464 #endif /* CONFIG_KPROBES */
 465 static inline int disable_kretprobe(struct kretprobe *rp)
 466 {
 467         return disable_kprobe(&rp->kp);
 468 }
 469 static inline int enable_kretprobe(struct kretprobe *rp)
 470 {
 471         return enable_kprobe(&rp->kp);
 472 }
 473 static inline int disable_jprobe(struct jprobe *jp)
 474 {
 475         return disable_kprobe(&jp->kp);
 476 }
 477 static 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)                        \
 488 static 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 */