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 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         /* Saved opcode (which has been replaced with breakpoint) */
 104         kprobe_opcode_t opcode;
 105
 106         /* copy of the original instruction */
 107         struct arch_specific_insn ainsn;
 108
 109         /*
 110          * Indicates various status flags.
 111          * Protected by kprobe_mutex after this kprobe is registered.
 112          */
 113         u32 flags;
 114 };
 115
 116 /* Kprobe status flags */
 117 #define KPROBE_FLAG_GONE        1 /* breakpoint has already gone */
 118 #define KPROBE_FLAG_DISABLED    2 /* probe is temporarily disabled */
 119 #define KPROBE_FLAG_OPTIMIZED   4 /*
 120                                    * probe is really optimized.
 121                                    * NOTE:
 122                                    * this flag is only for optimized_kprobe.
 123                                    */
 124 #define KPROBE_FLAG_FTRACE      8 /* probe is using ftrace */
 125
 126 /* Has this kprobe gone ? */
 127 static inline int kprobe_gone(struct kprobe *p)
 128 {
 129         return p->flags & KPROBE_FLAG_GONE;
 130 }
 131
 132 /* Is this kprobe disabled ? */
 133 static inline int kprobe_disabled(struct kprobe *p)
 134 {
 135         return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
 136 }
 137
 138 /* Is this kprobe really running optimized path ? */
 139 static inline int kprobe_optimized(struct kprobe *p)
 140 {
 141         return p->flags & KPROBE_FLAG_OPTIMIZED;
 142 }
 143
 144 /* Is this kprobe uses ftrace ? */
 145 static inline int kprobe_ftrace(struct kprobe *p)
 146 {
 147         return p->flags & KPROBE_FLAG_FTRACE;
 148 }
 149
 150 /*
 151  * Function-return probe -
 152  * Note:
 153  * User needs to provide a handler function, and initialize maxactive.
 154  * maxactive - The maximum number of instances of the probed function that
 155  * can be active concurrently.
 156  * nmissed - tracks the number of times the probed function's return was
 157  * ignored, due to maxactive being too low.
 158  *
 159  */
 160 struct kretprobe {
 161         struct kprobe kp;
 162         kretprobe_handler_t handler;
 163         kretprobe_handler_t entry_handler;
 164         int maxactive;
 165         int nmissed;
 166         size_t data_size;
 167         struct hlist_head free_instances;
 168         raw_spinlock_t lock;
 169 };
 170
 171 struct kretprobe_instance {
 172         struct hlist_node hlist;
 173         struct kretprobe *rp;
 174         kprobe_opcode_t *ret_addr;
 175         struct task_struct *task;
 176         char data[0];
 177 };
 178
 179 struct kretprobe_blackpoint {
 180         const char *name;
 181         void *addr;
 182 };
 183
 184 struct kprobe_blacklist_entry {
 185         struct list_head list;
 186         unsigned long start_addr;
 187         unsigned long end_addr;
 188 };
 189
 190 #ifdef CONFIG_KPROBES
 191 DECLARE_PER_CPU(struct kprobe *, current_kprobe);
 192 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 193
 194 /*
 195  * For #ifdef avoidance:
 196  */
 197 static inline int kprobes_built_in(void)
 198 {
 199         return 1;
 200 }
 201
 202 #ifdef CONFIG_KRETPROBES
 203 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
 204                                    struct pt_regs *regs);
 205 extern int arch_trampoline_kprobe(struct kprobe *p);
 206 #else /* CONFIG_KRETPROBES */
 207 static inline void arch_prepare_kretprobe(struct kretprobe *rp,
 208                                         struct pt_regs *regs)
 209 {
 210 }
 211 static inline int arch_trampoline_kprobe(struct kprobe *p)
 212 {
 213         return 0;
 214 }
 215 #endif /* CONFIG_KRETPROBES */
 216
 217 extern struct kretprobe_blackpoint kretprobe_blacklist[];
 218
 219 static inline void kretprobe_assert(struct kretprobe_instance *ri,
 220         unsigned long orig_ret_address, unsigned long trampoline_address)
 221 {
 222         if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
 223                 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
 224                                 ri->rp, ri->rp->kp.addr);
 225                 BUG();
 226         }
 227 }
 228
 229 #ifdef CONFIG_KPROBES_SANITY_TEST
 230 extern int init_test_probes(void);
 231 #else
 232 static inline int init_test_probes(void)
 233 {
 234         return 0;
 235 }
 236 #endif /* CONFIG_KPROBES_SANITY_TEST */
 237
 238 extern int arch_prepare_kprobe(struct kprobe *p);
 239 extern void arch_arm_kprobe(struct kprobe *p);
 240 extern void arch_disarm_kprobe(struct kprobe *p);
 241 extern int arch_init_kprobes(void);
 242 extern void show_registers(struct pt_regs *regs);
 243 extern void kprobes_inc_nmissed_count(struct kprobe *p);
 244 extern bool arch_within_kprobe_blacklist(unsigned long addr);
 245 extern bool arch_kprobe_on_func_entry(unsigned long offset);
 246 extern bool kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset);
 247
 248 extern bool within_kprobe_blacklist(unsigned long addr);
 249
 250 struct kprobe_insn_cache {
 251         struct mutex mutex;
 252         void *(*alloc)(void);   /* allocate insn page */
 253         void (*free)(void *);   /* free insn page */
 254         struct list_head pages; /* list of kprobe_insn_page */
 255         size_t insn_size;       /* size of instruction slot */
 256         int nr_garbage;
 257 };
 258
 259 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
 260 extern kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c);
 261 extern void __free_insn_slot(struct kprobe_insn_cache *c,
 262                              kprobe_opcode_t *slot, int dirty);
 263 /* sleep-less address checking routine  */
 264 extern bool __is_insn_slot_addr(struct kprobe_insn_cache *c,
 265                                 unsigned long addr);
 266
 267 #define DEFINE_INSN_CACHE_OPS(__name)                                   \
 268 extern struct kprobe_insn_cache kprobe_##__name##_slots;                \
 269                                                                         \
 270 static inline kprobe_opcode_t *get_##__name##_slot(void)                \
 271 {                                                                       \
 272         return __get_insn_slot(&kprobe_##__name##_slots);               \
 273 }                                                                       \
 274                                                                         \
 275 static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\
 276 {                                                                       \
 277         __free_insn_slot(&kprobe_##__name##_slots, slot, dirty);        \
 278 }                                                                       \
 279                                                                         \
 280 static inline bool is_kprobe_##__name##_slot(unsigned long addr)        \
 281 {                                                                       \
 282         return __is_insn_slot_addr(&kprobe_##__name##_slots, addr);     \
 283 }
 284 #else /* __ARCH_WANT_KPROBES_INSN_SLOT */
 285 #define DEFINE_INSN_CACHE_OPS(__name)                                   \
 286 static inline bool is_kprobe_##__name##_slot(unsigned long addr)        \
 287 {                                                                       \
 288         return 0;                                                       \
 289 }
 290 #endif
 291
 292 DEFINE_INSN_CACHE_OPS(insn);
 293
 294 #ifdef CONFIG_OPTPROBES
 295 /*
 296  * Internal structure for direct jump optimized probe
 297  */
 298 struct optimized_kprobe {
 299         struct kprobe kp;
 300         struct list_head list;  /* list for optimizing queue */
 301         struct arch_optimized_insn optinsn;
 302 };
 303
 304 /* Architecture dependent functions for direct jump optimization */
 305 extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
 306 extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
 307 extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op,
 308                                          struct kprobe *orig);
 309 extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
 310 extern void arch_optimize_kprobes(struct list_head *oplist);
 311 extern void arch_unoptimize_kprobes(struct list_head *oplist,
 312                                     struct list_head *done_list);
 313 extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
 314 extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
 315                                         unsigned long addr);
 316
 317 extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
 318
 319 DEFINE_INSN_CACHE_OPS(optinsn);
 320
 321 #ifdef CONFIG_SYSCTL
 322 extern int sysctl_kprobes_optimization;
 323 extern int proc_kprobes_optimization_handler(struct ctl_table *table,
 324                                              int write, void __user *buffer,
 325                                              size_t *length, loff_t *ppos);
 326 #endif
 327 extern void wait_for_kprobe_optimizer(void);
 328 #else
 329 static inline void wait_for_kprobe_optimizer(void) { }
 330 #endif /* CONFIG_OPTPROBES */
 331 #ifdef CONFIG_KPROBES_ON_FTRACE
 332 extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
 333                                   struct ftrace_ops *ops, struct pt_regs *regs);
 334 extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
 335 #endif
 336
 337 int arch_check_ftrace_location(struct kprobe *p);
 338
 339 /* Get the kprobe at this addr (if any) - called with preemption disabled */
 340 struct kprobe *get_kprobe(void *addr);
 341 void kretprobe_hash_lock(struct task_struct *tsk,
 342                          struct hlist_head **head, unsigned long *flags);
 343 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
 344 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
 345
 346 /* kprobe_running() will just return the current_kprobe on this CPU */
 347 static inline struct kprobe *kprobe_running(void)
 348 {
 349         return (__this_cpu_read(current_kprobe));
 350 }
 351
 352 static inline void reset_current_kprobe(void)
 353 {
 354         __this_cpu_write(current_kprobe, NULL);
 355 }
 356
 357 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
 358 {
 359         return this_cpu_ptr(&kprobe_ctlblk);
 360 }
 361
 362 kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset);
 363 int register_kprobe(struct kprobe *p);
 364 void unregister_kprobe(struct kprobe *p);
 365 int register_kprobes(struct kprobe **kps, int num);
 366 void unregister_kprobes(struct kprobe **kps, int num);
 367 unsigned long arch_deref_entry_point(void *);
 368
 369 int register_kretprobe(struct kretprobe *rp);
 370 void unregister_kretprobe(struct kretprobe *rp);
 371 int register_kretprobes(struct kretprobe **rps, int num);
 372 void unregister_kretprobes(struct kretprobe **rps, int num);
 373
 374 void kprobe_flush_task(struct task_struct *tk);
 375 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
 376
 377 int disable_kprobe(struct kprobe *kp);
 378 int enable_kprobe(struct kprobe *kp);
 379
 380 void dump_kprobe(struct kprobe *kp);
 381
 382 #else /* !CONFIG_KPROBES: */
 383
 384 static inline int kprobes_built_in(void)
 385 {
 386         return 0;
 387 }
 388 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 389 {
 390         return 0;
 391 }
 392 static inline struct kprobe *get_kprobe(void *addr)
 393 {
 394         return NULL;
 395 }
 396 static inline struct kprobe *kprobe_running(void)
 397 {
 398         return NULL;
 399 }
 400 static inline int register_kprobe(struct kprobe *p)
 401 {
 402         return -ENOSYS;
 403 }
 404 static inline int register_kprobes(struct kprobe **kps, int num)
 405 {
 406         return -ENOSYS;
 407 }
 408 static inline void unregister_kprobe(struct kprobe *p)
 409 {
 410 }
 411 static inline void unregister_kprobes(struct kprobe **kps, int num)
 412 {
 413 }
 414 static inline int register_kretprobe(struct kretprobe *rp)
 415 {
 416         return -ENOSYS;
 417 }
 418 static inline int register_kretprobes(struct kretprobe **rps, int num)
 419 {
 420         return -ENOSYS;
 421 }
 422 static inline void unregister_kretprobe(struct kretprobe *rp)
 423 {
 424 }
 425 static inline void unregister_kretprobes(struct kretprobe **rps, int num)
 426 {
 427 }
 428 static inline void kprobe_flush_task(struct task_struct *tk)
 429 {
 430 }
 431 static inline int disable_kprobe(struct kprobe *kp)
 432 {
 433         return -ENOSYS;
 434 }
 435 static inline int enable_kprobe(struct kprobe *kp)
 436 {
 437         return -ENOSYS;
 438 }
 439 #endif /* CONFIG_KPROBES */
 440 static inline int disable_kretprobe(struct kretprobe *rp)
 441 {
 442         return disable_kprobe(&rp->kp);
 443 }
 444 static inline int enable_kretprobe(struct kretprobe *rp)
 445 {
 446         return enable_kprobe(&rp->kp);
 447 }
 448
 449 #ifndef CONFIG_KPROBES
 450 static inline bool is_kprobe_insn_slot(unsigned long addr)
 451 {
 452         return false;
 453 }
 454 #endif
 455 #ifndef CONFIG_OPTPROBES
 456 static inline bool is_kprobe_optinsn_slot(unsigned long addr)
 457 {
 458         return false;
 459 }
 460 #endif
 461
 462 #endif /* _LINUX_KPROBES_H */