kprobes.h 13 KB

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  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. #ifdef CONFIG_KPROBES
  44. #include <asm/kprobes.h>
  45. /* kprobe_status settings */
  46. #define KPROBE_HIT_ACTIVE 0x00000001
  47. #define KPROBE_HIT_SS 0x00000002
  48. #define KPROBE_REENTER 0x00000004
  49. #define KPROBE_HIT_SSDONE 0x00000008
  50. #else /* CONFIG_KPROBES */
  51. typedef int kprobe_opcode_t;
  52. struct arch_specific_insn {
  53. int dummy;
  54. };
  55. #endif /* CONFIG_KPROBES */
  56. struct kprobe;
  57. struct pt_regs;
  58. struct kretprobe;
  59. struct kretprobe_instance;
  60. typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
  61. typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *);
  62. typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
  63. unsigned long flags);
  64. typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
  65. int trapnr);
  66. typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
  67. struct pt_regs *);
  68. struct kprobe {
  69. struct hlist_node hlist;
  70. /* list of kprobes for multi-handler support */
  71. struct list_head list;
  72. /*count the number of times this probe was temporarily disarmed */
  73. unsigned long nmissed;
  74. /* location of the probe point */
  75. kprobe_opcode_t *addr;
  76. /* Allow user to indicate symbol name of the probe point */
  77. const char *symbol_name;
  78. /* Offset into the symbol */
  79. unsigned int offset;
  80. /* Called before addr is executed. */
  81. kprobe_pre_handler_t pre_handler;
  82. /* Called after addr is executed, unless... */
  83. kprobe_post_handler_t post_handler;
  84. /*
  85. * ... called if executing addr causes a fault (eg. page fault).
  86. * Return 1 if it handled fault, otherwise kernel will see it.
  87. */
  88. kprobe_fault_handler_t fault_handler;
  89. /*
  90. * ... called if breakpoint trap occurs in probe handler.
  91. * Return 1 if it handled break, otherwise kernel will see it.
  92. */
  93. kprobe_break_handler_t break_handler;
  94. /* Saved opcode (which has been replaced with breakpoint) */
  95. kprobe_opcode_t opcode;
  96. /* copy of the original instruction */
  97. struct arch_specific_insn ainsn;
  98. /*
  99. * Indicates various status flags.
  100. * Protected by kprobe_mutex after this kprobe is registered.
  101. */
  102. u32 flags;
  103. };
  104. /* Kprobe status flags */
  105. #define KPROBE_FLAG_GONE 1 /* breakpoint has already gone */
  106. #define KPROBE_FLAG_DISABLED 2 /* probe is temporarily disabled */
  107. #define KPROBE_FLAG_OPTIMIZED 4 /*
  108. * probe is really optimized.
  109. * NOTE:
  110. * this flag is only for optimized_kprobe.
  111. */
  112. #define KPROBE_FLAG_FTRACE 8 /* probe is using ftrace */
  113. /* Has this kprobe gone ? */
  114. static inline int kprobe_gone(struct kprobe *p)
  115. {
  116. return p->flags & KPROBE_FLAG_GONE;
  117. }
  118. /* Is this kprobe disabled ? */
  119. static inline int kprobe_disabled(struct kprobe *p)
  120. {
  121. return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
  122. }
  123. /* Is this kprobe really running optimized path ? */
  124. static inline int kprobe_optimized(struct kprobe *p)
  125. {
  126. return p->flags & KPROBE_FLAG_OPTIMIZED;
  127. }
  128. /* Is this kprobe uses ftrace ? */
  129. static inline int kprobe_ftrace(struct kprobe *p)
  130. {
  131. return p->flags & KPROBE_FLAG_FTRACE;
  132. }
  133. /*
  134. * Special probe type that uses setjmp-longjmp type tricks to resume
  135. * execution at a specified entry with a matching prototype corresponding
  136. * to the probed function - a trick to enable arguments to become
  137. * accessible seamlessly by probe handling logic.
  138. * Note:
  139. * Because of the way compilers allocate stack space for local variables
  140. * etc upfront, regardless of sub-scopes within a function, this mirroring
  141. * principle currently works only for probes placed on function entry points.
  142. */
  143. struct jprobe {
  144. struct kprobe kp;
  145. void *entry; /* probe handling code to jump to */
  146. };
  147. /* For backward compatibility with old code using JPROBE_ENTRY() */
  148. #define JPROBE_ENTRY(handler) (handler)
  149. /*
  150. * Function-return probe -
  151. * Note:
  152. * User needs to provide a handler function, and initialize maxactive.
  153. * maxactive - The maximum number of instances of the probed function that
  154. * can be active concurrently.
  155. * nmissed - tracks the number of times the probed function's return was
  156. * ignored, due to maxactive being too low.
  157. *
  158. */
  159. struct kretprobe {
  160. struct kprobe kp;
  161. kretprobe_handler_t handler;
  162. kretprobe_handler_t entry_handler;
  163. int maxactive;
  164. int nmissed;
  165. size_t data_size;
  166. struct hlist_head free_instances;
  167. raw_spinlock_t lock;
  168. };
  169. struct kretprobe_instance {
  170. struct hlist_node hlist;
  171. struct kretprobe *rp;
  172. kprobe_opcode_t *ret_addr;
  173. struct task_struct *task;
  174. char data[0];
  175. };
  176. struct kretprobe_blackpoint {
  177. const char *name;
  178. void *addr;
  179. };
  180. struct kprobe_blackpoint {
  181. const char *name;
  182. unsigned long start_addr;
  183. unsigned long range;
  184. };
  185. #ifdef CONFIG_KPROBES
  186. DECLARE_PER_CPU(struct kprobe *, current_kprobe);
  187. DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
  188. /*
  189. * For #ifdef avoidance:
  190. */
  191. static inline int kprobes_built_in(void)
  192. {
  193. return 1;
  194. }
  195. #ifdef CONFIG_KRETPROBES
  196. extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
  197. struct pt_regs *regs);
  198. extern int arch_trampoline_kprobe(struct kprobe *p);
  199. #else /* CONFIG_KRETPROBES */
  200. static inline void arch_prepare_kretprobe(struct kretprobe *rp,
  201. struct pt_regs *regs)
  202. {
  203. }
  204. static inline int arch_trampoline_kprobe(struct kprobe *p)
  205. {
  206. return 0;
  207. }
  208. #endif /* CONFIG_KRETPROBES */
  209. extern struct kretprobe_blackpoint kretprobe_blacklist[];
  210. static inline void kretprobe_assert(struct kretprobe_instance *ri,
  211. unsigned long orig_ret_address, unsigned long trampoline_address)
  212. {
  213. if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
  214. printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
  215. ri->rp, ri->rp->kp.addr);
  216. BUG();
  217. }
  218. }
  219. #ifdef CONFIG_KPROBES_SANITY_TEST
  220. extern int init_test_probes(void);
  221. #else
  222. static inline int init_test_probes(void)
  223. {
  224. return 0;
  225. }
  226. #endif /* CONFIG_KPROBES_SANITY_TEST */
  227. extern int arch_prepare_kprobe(struct kprobe *p);
  228. extern void arch_arm_kprobe(struct kprobe *p);
  229. extern void arch_disarm_kprobe(struct kprobe *p);
  230. extern int arch_init_kprobes(void);
  231. extern void show_registers(struct pt_regs *regs);
  232. extern kprobe_opcode_t *get_insn_slot(void);
  233. extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
  234. extern void kprobes_inc_nmissed_count(struct kprobe *p);
  235. #ifdef CONFIG_OPTPROBES
  236. /*
  237. * Internal structure for direct jump optimized probe
  238. */
  239. struct optimized_kprobe {
  240. struct kprobe kp;
  241. struct list_head list; /* list for optimizing queue */
  242. struct arch_optimized_insn optinsn;
  243. };
  244. /* Architecture dependent functions for direct jump optimization */
  245. extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
  246. extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
  247. extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op);
  248. extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
  249. extern void arch_optimize_kprobes(struct list_head *oplist);
  250. extern void arch_unoptimize_kprobes(struct list_head *oplist,
  251. struct list_head *done_list);
  252. extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
  253. extern kprobe_opcode_t *get_optinsn_slot(void);
  254. extern void free_optinsn_slot(kprobe_opcode_t *slot, int dirty);
  255. extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
  256. unsigned long addr);
  257. extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
  258. #ifdef CONFIG_SYSCTL
  259. extern int sysctl_kprobes_optimization;
  260. extern int proc_kprobes_optimization_handler(struct ctl_table *table,
  261. int write, void __user *buffer,
  262. size_t *length, loff_t *ppos);
  263. #endif
  264. #endif /* CONFIG_OPTPROBES */
  265. #ifdef CONFIG_KPROBES_ON_FTRACE
  266. extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
  267. struct ftrace_ops *ops, struct pt_regs *regs);
  268. extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
  269. #endif
  270. /* Get the kprobe at this addr (if any) - called with preemption disabled */
  271. struct kprobe *get_kprobe(void *addr);
  272. void kretprobe_hash_lock(struct task_struct *tsk,
  273. struct hlist_head **head, unsigned long *flags);
  274. void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
  275. struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
  276. /* kprobe_running() will just return the current_kprobe on this CPU */
  277. static inline struct kprobe *kprobe_running(void)
  278. {
  279. return (__this_cpu_read(current_kprobe));
  280. }
  281. static inline void reset_current_kprobe(void)
  282. {
  283. __this_cpu_write(current_kprobe, NULL);
  284. }
  285. static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
  286. {
  287. return (&__get_cpu_var(kprobe_ctlblk));
  288. }
  289. int register_kprobe(struct kprobe *p);
  290. void unregister_kprobe(struct kprobe *p);
  291. int register_kprobes(struct kprobe **kps, int num);
  292. void unregister_kprobes(struct kprobe **kps, int num);
  293. int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
  294. int longjmp_break_handler(struct kprobe *, struct pt_regs *);
  295. int register_jprobe(struct jprobe *p);
  296. void unregister_jprobe(struct jprobe *p);
  297. int register_jprobes(struct jprobe **jps, int num);
  298. void unregister_jprobes(struct jprobe **jps, int num);
  299. void jprobe_return(void);
  300. unsigned long arch_deref_entry_point(void *);
  301. int register_kretprobe(struct kretprobe *rp);
  302. void unregister_kretprobe(struct kretprobe *rp);
  303. int register_kretprobes(struct kretprobe **rps, int num);
  304. void unregister_kretprobes(struct kretprobe **rps, int num);
  305. void kprobe_flush_task(struct task_struct *tk);
  306. void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
  307. int disable_kprobe(struct kprobe *kp);
  308. int enable_kprobe(struct kprobe *kp);
  309. void dump_kprobe(struct kprobe *kp);
  310. #else /* !CONFIG_KPROBES: */
  311. static inline int kprobes_built_in(void)
  312. {
  313. return 0;
  314. }
  315. static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
  316. {
  317. return 0;
  318. }
  319. static inline struct kprobe *get_kprobe(void *addr)
  320. {
  321. return NULL;
  322. }
  323. static inline struct kprobe *kprobe_running(void)
  324. {
  325. return NULL;
  326. }
  327. static inline int register_kprobe(struct kprobe *p)
  328. {
  329. return -ENOSYS;
  330. }
  331. static inline int register_kprobes(struct kprobe **kps, int num)
  332. {
  333. return -ENOSYS;
  334. }
  335. static inline void unregister_kprobe(struct kprobe *p)
  336. {
  337. }
  338. static inline void unregister_kprobes(struct kprobe **kps, int num)
  339. {
  340. }
  341. static inline int register_jprobe(struct jprobe *p)
  342. {
  343. return -ENOSYS;
  344. }
  345. static inline int register_jprobes(struct jprobe **jps, int num)
  346. {
  347. return -ENOSYS;
  348. }
  349. static inline void unregister_jprobe(struct jprobe *p)
  350. {
  351. }
  352. static inline void unregister_jprobes(struct jprobe **jps, int num)
  353. {
  354. }
  355. static inline void jprobe_return(void)
  356. {
  357. }
  358. static inline int register_kretprobe(struct kretprobe *rp)
  359. {
  360. return -ENOSYS;
  361. }
  362. static inline int register_kretprobes(struct kretprobe **rps, int num)
  363. {
  364. return -ENOSYS;
  365. }
  366. static inline void unregister_kretprobe(struct kretprobe *rp)
  367. {
  368. }
  369. static inline void unregister_kretprobes(struct kretprobe **rps, int num)
  370. {
  371. }
  372. static inline void kprobe_flush_task(struct task_struct *tk)
  373. {
  374. }
  375. static inline int disable_kprobe(struct kprobe *kp)
  376. {
  377. return -ENOSYS;
  378. }
  379. static inline int enable_kprobe(struct kprobe *kp)
  380. {
  381. return -ENOSYS;
  382. }
  383. #endif /* CONFIG_KPROBES */
  384. static inline int disable_kretprobe(struct kretprobe *rp)
  385. {
  386. return disable_kprobe(&rp->kp);
  387. }
  388. static inline int enable_kretprobe(struct kretprobe *rp)
  389. {
  390. return enable_kprobe(&rp->kp);
  391. }
  392. static inline int disable_jprobe(struct jprobe *jp)
  393. {
  394. return disable_kprobe(&jp->kp);
  395. }
  396. static inline int enable_jprobe(struct jprobe *jp)
  397. {
  398. return enable_kprobe(&jp->kp);
  399. }
  400. #endif /* _LINUX_KPROBES_H */