kprobes.h 7.5 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/list.h>
  33. #include <linux/notifier.h>
  34. #include <linux/smp.h>
  35. #include <linux/percpu.h>
  36. #include <linux/spinlock.h>
  37. #include <linux/rcupdate.h>
  38. #include <linux/mutex.h>
  39. #ifdef CONFIG_KPROBES
  40. #include <asm/kprobes.h>
  41. /* kprobe_status settings */
  42. #define KPROBE_HIT_ACTIVE 0x00000001
  43. #define KPROBE_HIT_SS 0x00000002
  44. #define KPROBE_REENTER 0x00000004
  45. #define KPROBE_HIT_SSDONE 0x00000008
  46. /* Attach to insert probes on any functions which should be ignored*/
  47. #define __kprobes __attribute__((__section__(".kprobes.text")))
  48. struct kprobe;
  49. struct pt_regs;
  50. struct kretprobe;
  51. struct kretprobe_instance;
  52. typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
  53. typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *);
  54. typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
  55. unsigned long flags);
  56. typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
  57. int trapnr);
  58. typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
  59. struct pt_regs *);
  60. struct kprobe {
  61. struct hlist_node hlist;
  62. /* list of kprobes for multi-handler support */
  63. struct list_head list;
  64. /* Indicates that the corresponding module has been ref counted */
  65. unsigned int mod_refcounted;
  66. /*count the number of times this probe was temporarily disarmed */
  67. unsigned long nmissed;
  68. /* location of the probe point */
  69. kprobe_opcode_t *addr;
  70. /* Allow user to indicate symbol name of the probe point */
  71. char *symbol_name;
  72. /* Offset into the symbol */
  73. unsigned int offset;
  74. /* Called before addr is executed. */
  75. kprobe_pre_handler_t pre_handler;
  76. /* Called after addr is executed, unless... */
  77. kprobe_post_handler_t post_handler;
  78. /* ... called if executing addr causes a fault (eg. page fault).
  79. * Return 1 if it handled fault, otherwise kernel will see it. */
  80. kprobe_fault_handler_t fault_handler;
  81. /* ... called if breakpoint trap occurs in probe handler.
  82. * Return 1 if it handled break, otherwise kernel will see it. */
  83. kprobe_break_handler_t break_handler;
  84. /* Saved opcode (which has been replaced with breakpoint) */
  85. kprobe_opcode_t opcode;
  86. /* copy of the original instruction */
  87. struct arch_specific_insn ainsn;
  88. };
  89. /*
  90. * Special probe type that uses setjmp-longjmp type tricks to resume
  91. * execution at a specified entry with a matching prototype corresponding
  92. * to the probed function - a trick to enable arguments to become
  93. * accessible seamlessly by probe handling logic.
  94. * Note:
  95. * Because of the way compilers allocate stack space for local variables
  96. * etc upfront, regardless of sub-scopes within a function, this mirroring
  97. * principle currently works only for probes placed on function entry points.
  98. */
  99. struct jprobe {
  100. struct kprobe kp;
  101. kprobe_opcode_t *entry; /* probe handling code to jump to */
  102. };
  103. DECLARE_PER_CPU(struct kprobe *, current_kprobe);
  104. DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
  105. #ifdef ARCH_SUPPORTS_KRETPROBES
  106. extern void arch_prepare_kretprobe(struct kretprobe *rp, struct pt_regs *regs);
  107. #else /* ARCH_SUPPORTS_KRETPROBES */
  108. static inline void arch_prepare_kretprobe(struct kretprobe *rp,
  109. struct pt_regs *regs)
  110. {
  111. }
  112. #endif /* ARCH_SUPPORTS_KRETPROBES */
  113. /*
  114. * Function-return probe -
  115. * Note:
  116. * User needs to provide a handler function, and initialize maxactive.
  117. * maxactive - The maximum number of instances of the probed function that
  118. * can be active concurrently.
  119. * nmissed - tracks the number of times the probed function's return was
  120. * ignored, due to maxactive being too low.
  121. *
  122. */
  123. struct kretprobe {
  124. struct kprobe kp;
  125. kretprobe_handler_t handler;
  126. int maxactive;
  127. int nmissed;
  128. struct hlist_head free_instances;
  129. struct hlist_head used_instances;
  130. };
  131. struct kretprobe_instance {
  132. struct hlist_node uflist; /* either on free list or used list */
  133. struct hlist_node hlist;
  134. struct kretprobe *rp;
  135. kprobe_opcode_t *ret_addr;
  136. struct task_struct *task;
  137. };
  138. extern spinlock_t kretprobe_lock;
  139. extern struct mutex kprobe_mutex;
  140. extern int arch_prepare_kprobe(struct kprobe *p);
  141. extern void arch_arm_kprobe(struct kprobe *p);
  142. extern void arch_disarm_kprobe(struct kprobe *p);
  143. extern int arch_init_kprobes(void);
  144. extern void show_registers(struct pt_regs *regs);
  145. extern kprobe_opcode_t *get_insn_slot(void);
  146. extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
  147. extern void kprobes_inc_nmissed_count(struct kprobe *p);
  148. /* Get the kprobe at this addr (if any) - called with preemption disabled */
  149. struct kprobe *get_kprobe(void *addr);
  150. struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
  151. /* kprobe_running() will just return the current_kprobe on this CPU */
  152. static inline struct kprobe *kprobe_running(void)
  153. {
  154. return (__get_cpu_var(current_kprobe));
  155. }
  156. static inline void reset_current_kprobe(void)
  157. {
  158. __get_cpu_var(current_kprobe) = NULL;
  159. }
  160. static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
  161. {
  162. return (&__get_cpu_var(kprobe_ctlblk));
  163. }
  164. int register_kprobe(struct kprobe *p);
  165. void unregister_kprobe(struct kprobe *p);
  166. int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
  167. int longjmp_break_handler(struct kprobe *, struct pt_regs *);
  168. int register_jprobe(struct jprobe *p);
  169. void unregister_jprobe(struct jprobe *p);
  170. void jprobe_return(void);
  171. int register_kretprobe(struct kretprobe *rp);
  172. void unregister_kretprobe(struct kretprobe *rp);
  173. struct kretprobe_instance *get_free_rp_inst(struct kretprobe *rp);
  174. void add_rp_inst(struct kretprobe_instance *ri);
  175. void kprobe_flush_task(struct task_struct *tk);
  176. void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
  177. #else /* CONFIG_KPROBES */
  178. #define __kprobes /**/
  179. struct jprobe;
  180. struct kretprobe;
  181. static inline struct kprobe *kprobe_running(void)
  182. {
  183. return NULL;
  184. }
  185. static inline int register_kprobe(struct kprobe *p)
  186. {
  187. return -ENOSYS;
  188. }
  189. static inline void unregister_kprobe(struct kprobe *p)
  190. {
  191. }
  192. static inline int register_jprobe(struct jprobe *p)
  193. {
  194. return -ENOSYS;
  195. }
  196. static inline void unregister_jprobe(struct jprobe *p)
  197. {
  198. }
  199. static inline void jprobe_return(void)
  200. {
  201. }
  202. static inline int register_kretprobe(struct kretprobe *rp)
  203. {
  204. return -ENOSYS;
  205. }
  206. static inline void unregister_kretprobe(struct kretprobe *rp)
  207. {
  208. }
  209. static inline void kprobe_flush_task(struct task_struct *tk)
  210. {
  211. }
  212. #endif /* CONFIG_KPROBES */
  213. #endif /* _LINUX_KPROBES_H */