Merge branch 'docs-next' of git://git.lwn.net/linux-2.6
[linux-2.6/next.git] / include / linux / kprobes.h
blob3a46b7b7abb219c40bf39ce4d5f4e448da131212
1 #ifndef _LINUX_KPROBES_H
2 #define _LINUX_KPROBES_H
3 /*
4 * Kernel Probes (KProbes)
5 * include/linux/kprobes.h
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.
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.
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.
21 * Copyright (C) IBM Corporation, 2002, 2004
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.
32 #include <linux/linkage.h>
33 #include <linux/list.h>
34 #include <linux/notifier.h>
35 #include <linux/smp.h>
36 #include <linux/percpu.h>
37 #include <linux/spinlock.h>
38 #include <linux/rcupdate.h>
39 #include <linux/mutex.h>
41 #ifdef CONFIG_KPROBES
42 #include <asm/kprobes.h>
44 /* kprobe_status settings */
45 #define KPROBE_HIT_ACTIVE 0x00000001
46 #define KPROBE_HIT_SS 0x00000002
47 #define KPROBE_REENTER 0x00000004
48 #define KPROBE_HIT_SSDONE 0x00000008
50 /* Attach to insert probes on any functions which should be ignored*/
51 #define __kprobes __attribute__((__section__(".kprobes.text")))
52 #else /* CONFIG_KPROBES */
53 typedef int kprobe_opcode_t;
54 struct arch_specific_insn {
55 int dummy;
57 #define __kprobes
58 #endif /* CONFIG_KPROBES */
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 *);
73 struct kprobe {
74 struct hlist_node hlist;
76 /* list of kprobes for multi-handler support */
77 struct list_head list;
79 /*count the number of times this probe was temporarily disarmed */
80 unsigned long nmissed;
82 /* location of the probe point */
83 kprobe_opcode_t *addr;
85 /* Allow user to indicate symbol name of the probe point */
86 const char *symbol_name;
88 /* Offset into the symbol */
89 unsigned int offset;
91 /* Called before addr is executed. */
92 kprobe_pre_handler_t pre_handler;
94 /* Called after addr is executed, unless... */
95 kprobe_post_handler_t post_handler;
98 * ... called if executing addr causes a fault (eg. page fault).
99 * Return 1 if it handled fault, otherwise kernel will see it.
101 kprobe_fault_handler_t fault_handler;
104 * ... called if breakpoint trap occurs in probe handler.
105 * Return 1 if it handled break, otherwise kernel will see it.
107 kprobe_break_handler_t break_handler;
109 /* Saved opcode (which has been replaced with breakpoint) */
110 kprobe_opcode_t opcode;
112 /* copy of the original instruction */
113 struct arch_specific_insn ainsn;
116 * Indicates various status flags.
117 * Protected by kprobe_mutex after this kprobe is registered.
119 u32 flags;
122 /* Kprobe status flags */
123 #define KPROBE_FLAG_GONE 1 /* breakpoint has already gone */
124 #define KPROBE_FLAG_DISABLED 2 /* probe is temporarily disabled */
126 /* Has this kprobe gone ? */
127 static inline int kprobe_gone(struct kprobe *p)
129 return p->flags & KPROBE_FLAG_GONE;
132 /* Is this kprobe disabled ? */
133 static inline int kprobe_disabled(struct kprobe *p)
135 return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
138 * Special probe type that uses setjmp-longjmp type tricks to resume
139 * execution at a specified entry with a matching prototype corresponding
140 * to the probed function - a trick to enable arguments to become
141 * accessible seamlessly by probe handling logic.
142 * Note:
143 * Because of the way compilers allocate stack space for local variables
144 * etc upfront, regardless of sub-scopes within a function, this mirroring
145 * principle currently works only for probes placed on function entry points.
147 struct jprobe {
148 struct kprobe kp;
149 void *entry; /* probe handling code to jump to */
152 /* For backward compatibility with old code using JPROBE_ENTRY() */
153 #define JPROBE_ENTRY(handler) (handler)
156 * Function-return probe -
157 * Note:
158 * User needs to provide a handler function, and initialize maxactive.
159 * maxactive - The maximum number of instances of the probed function that
160 * can be active concurrently.
161 * nmissed - tracks the number of times the probed function's return was
162 * ignored, due to maxactive being too low.
165 struct kretprobe {
166 struct kprobe kp;
167 kretprobe_handler_t handler;
168 kretprobe_handler_t entry_handler;
169 int maxactive;
170 int nmissed;
171 size_t data_size;
172 struct hlist_head free_instances;
173 spinlock_t lock;
176 struct kretprobe_instance {
177 struct hlist_node hlist;
178 struct kretprobe *rp;
179 kprobe_opcode_t *ret_addr;
180 struct task_struct *task;
181 char data[0];
184 struct kretprobe_blackpoint {
185 const char *name;
186 void *addr;
189 struct kprobe_blackpoint {
190 const char *name;
191 unsigned long start_addr;
192 unsigned long range;
195 #ifdef CONFIG_KPROBES
196 DECLARE_PER_CPU(struct kprobe *, current_kprobe);
197 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
200 * For #ifdef avoidance:
202 static inline int kprobes_built_in(void)
204 return 1;
207 #ifdef CONFIG_KRETPROBES
208 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
209 struct pt_regs *regs);
210 extern int arch_trampoline_kprobe(struct kprobe *p);
211 #else /* CONFIG_KRETPROBES */
212 static inline void arch_prepare_kretprobe(struct kretprobe *rp,
213 struct pt_regs *regs)
216 static inline int arch_trampoline_kprobe(struct kprobe *p)
218 return 0;
220 #endif /* CONFIG_KRETPROBES */
222 extern struct kretprobe_blackpoint kretprobe_blacklist[];
224 static inline void kretprobe_assert(struct kretprobe_instance *ri,
225 unsigned long orig_ret_address, unsigned long trampoline_address)
227 if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
228 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
229 ri->rp, ri->rp->kp.addr);
230 BUG();
234 #ifdef CONFIG_KPROBES_SANITY_TEST
235 extern int init_test_probes(void);
236 #else
237 static inline int init_test_probes(void)
239 return 0;
241 #endif /* CONFIG_KPROBES_SANITY_TEST */
243 extern int arch_prepare_kprobe(struct kprobe *p);
244 extern void arch_arm_kprobe(struct kprobe *p);
245 extern void arch_disarm_kprobe(struct kprobe *p);
246 extern int arch_init_kprobes(void);
247 extern void show_registers(struct pt_regs *regs);
248 extern kprobe_opcode_t *get_insn_slot(void);
249 extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
250 extern void kprobes_inc_nmissed_count(struct kprobe *p);
252 /* Get the kprobe at this addr (if any) - called with preemption disabled */
253 struct kprobe *get_kprobe(void *addr);
254 void kretprobe_hash_lock(struct task_struct *tsk,
255 struct hlist_head **head, unsigned long *flags);
256 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
257 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
259 /* kprobe_running() will just return the current_kprobe on this CPU */
260 static inline struct kprobe *kprobe_running(void)
262 return (__get_cpu_var(current_kprobe));
265 static inline void reset_current_kprobe(void)
267 __get_cpu_var(current_kprobe) = NULL;
270 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
272 return (&__get_cpu_var(kprobe_ctlblk));
275 int register_kprobe(struct kprobe *p);
276 void unregister_kprobe(struct kprobe *p);
277 int register_kprobes(struct kprobe **kps, int num);
278 void unregister_kprobes(struct kprobe **kps, int num);
279 int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
280 int longjmp_break_handler(struct kprobe *, struct pt_regs *);
281 int register_jprobe(struct jprobe *p);
282 void unregister_jprobe(struct jprobe *p);
283 int register_jprobes(struct jprobe **jps, int num);
284 void unregister_jprobes(struct jprobe **jps, int num);
285 void jprobe_return(void);
286 unsigned long arch_deref_entry_point(void *);
288 int register_kretprobe(struct kretprobe *rp);
289 void unregister_kretprobe(struct kretprobe *rp);
290 int register_kretprobes(struct kretprobe **rps, int num);
291 void unregister_kretprobes(struct kretprobe **rps, int num);
293 void kprobe_flush_task(struct task_struct *tk);
294 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
296 int disable_kprobe(struct kprobe *kp);
297 int enable_kprobe(struct kprobe *kp);
299 #else /* !CONFIG_KPROBES: */
301 static inline int kprobes_built_in(void)
303 return 0;
305 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
307 return 0;
309 static inline struct kprobe *get_kprobe(void *addr)
311 return NULL;
313 static inline struct kprobe *kprobe_running(void)
315 return NULL;
317 static inline int register_kprobe(struct kprobe *p)
319 return -ENOSYS;
321 static inline int register_kprobes(struct kprobe **kps, int num)
323 return -ENOSYS;
325 static inline void unregister_kprobe(struct kprobe *p)
328 static inline void unregister_kprobes(struct kprobe **kps, int num)
331 static inline int register_jprobe(struct jprobe *p)
333 return -ENOSYS;
335 static inline int register_jprobes(struct jprobe **jps, int num)
337 return -ENOSYS;
339 static inline void unregister_jprobe(struct jprobe *p)
342 static inline void unregister_jprobes(struct jprobe **jps, int num)
345 static inline void jprobe_return(void)
348 static inline int register_kretprobe(struct kretprobe *rp)
350 return -ENOSYS;
352 static inline int register_kretprobes(struct kretprobe **rps, int num)
354 return -ENOSYS;
356 static inline void unregister_kretprobe(struct kretprobe *rp)
359 static inline void unregister_kretprobes(struct kretprobe **rps, int num)
362 static inline void kprobe_flush_task(struct task_struct *tk)
365 static inline int disable_kprobe(struct kprobe *kp)
367 return -ENOSYS;
369 static inline int enable_kprobe(struct kprobe *kp)
371 return -ENOSYS;
373 #endif /* CONFIG_KPROBES */
374 static inline int disable_kretprobe(struct kretprobe *rp)
376 return disable_kprobe(&rp->kp);
378 static inline int enable_kretprobe(struct kretprobe *rp)
380 return enable_kprobe(&rp->kp);
382 static inline int disable_jprobe(struct jprobe *jp)
384 return disable_kprobe(&jp->kp);
386 static inline int enable_jprobe(struct jprobe *jp)
388 return enable_kprobe(&jp->kp);
391 #endif /* _LINUX_KPROBES_H */