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 ? */
kprobe_gone(struct kprobe * p)127 static inline int kprobe_gone(struct kprobe *p)
128 {
129 return p->flags & KPROBE_FLAG_GONE;
130 }
131
132 /* Is this kprobe disabled ? */
kprobe_disabled(struct kprobe * p)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 ? */
kprobe_optimized(struct kprobe * p)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 ? */
kprobe_ftrace(struct kprobe * p)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 #define KRETPROBE_MAX_DATA_SIZE 4096
172
173 struct kretprobe_instance {
174 struct hlist_node hlist;
175 struct kretprobe *rp;
176 kprobe_opcode_t *ret_addr;
177 struct task_struct *task;
178 void *fp;
179 char data[0];
180 };
181
182 struct kretprobe_blackpoint {
183 const char *name;
184 void *addr;
185 };
186
187 struct kprobe_blacklist_entry {
188 struct list_head list;
189 unsigned long start_addr;
190 unsigned long end_addr;
191 };
192
193 #ifdef CONFIG_KPROBES
194 DECLARE_PER_CPU(struct kprobe *, current_kprobe);
195 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
196
197 /*
198 * For #ifdef avoidance:
199 */
kprobes_built_in(void)200 static inline int kprobes_built_in(void)
201 {
202 return 1;
203 }
204
205 #ifdef CONFIG_KRETPROBES
206 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
207 struct pt_regs *regs);
208 extern int arch_trampoline_kprobe(struct kprobe *p);
209 #else /* CONFIG_KRETPROBES */
arch_prepare_kretprobe(struct kretprobe * rp,struct pt_regs * regs)210 static inline void arch_prepare_kretprobe(struct kretprobe *rp,
211 struct pt_regs *regs)
212 {
213 }
arch_trampoline_kprobe(struct kprobe * p)214 static inline int arch_trampoline_kprobe(struct kprobe *p)
215 {
216 return 0;
217 }
218 #endif /* CONFIG_KRETPROBES */
219
220 extern struct kretprobe_blackpoint kretprobe_blacklist[];
221
kretprobe_assert(struct kretprobe_instance * ri,unsigned long orig_ret_address,unsigned long trampoline_address)222 static inline void kretprobe_assert(struct kretprobe_instance *ri,
223 unsigned long orig_ret_address, unsigned long trampoline_address)
224 {
225 if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
226 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
227 ri->rp, ri->rp->kp.addr);
228 BUG();
229 }
230 }
231
232 #ifdef CONFIG_KPROBES_SANITY_TEST
233 extern int init_test_probes(void);
234 #else
init_test_probes(void)235 static inline int init_test_probes(void)
236 {
237 return 0;
238 }
239 #endif /* CONFIG_KPROBES_SANITY_TEST */
240
241 extern int arch_prepare_kprobe(struct kprobe *p);
242 extern void arch_arm_kprobe(struct kprobe *p);
243 extern void arch_disarm_kprobe(struct kprobe *p);
244 extern int arch_init_kprobes(void);
245 extern void show_registers(struct pt_regs *regs);
246 extern void kprobes_inc_nmissed_count(struct kprobe *p);
247 extern bool arch_within_kprobe_blacklist(unsigned long addr);
248 extern int arch_populate_kprobe_blacklist(void);
249 extern bool arch_kprobe_on_func_entry(unsigned long offset);
250 extern int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset);
251
252 extern bool within_kprobe_blacklist(unsigned long addr);
253 extern int kprobe_add_ksym_blacklist(unsigned long entry);
254 extern int kprobe_add_area_blacklist(unsigned long start, unsigned long end);
255
256 struct kprobe_insn_cache {
257 struct mutex mutex;
258 void *(*alloc)(void); /* allocate insn page */
259 void (*free)(void *); /* free insn page */
260 struct list_head pages; /* list of kprobe_insn_page */
261 size_t insn_size; /* size of instruction slot */
262 int nr_garbage;
263 };
264
265 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
266 extern kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c);
267 extern void __free_insn_slot(struct kprobe_insn_cache *c,
268 kprobe_opcode_t *slot, int dirty);
269 /* sleep-less address checking routine */
270 extern bool __is_insn_slot_addr(struct kprobe_insn_cache *c,
271 unsigned long addr);
272
273 #define DEFINE_INSN_CACHE_OPS(__name) \
274 extern struct kprobe_insn_cache kprobe_##__name##_slots; \
275 \
276 static inline kprobe_opcode_t *get_##__name##_slot(void) \
277 { \
278 return __get_insn_slot(&kprobe_##__name##_slots); \
279 } \
280 \
281 static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\
282 { \
283 __free_insn_slot(&kprobe_##__name##_slots, slot, dirty); \
284 } \
285 \
286 static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
287 { \
288 return __is_insn_slot_addr(&kprobe_##__name##_slots, addr); \
289 }
290 #else /* __ARCH_WANT_KPROBES_INSN_SLOT */
291 #define DEFINE_INSN_CACHE_OPS(__name) \
292 static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
293 { \
294 return 0; \
295 }
296 #endif
297
298 DEFINE_INSN_CACHE_OPS(insn);
299
300 #ifdef CONFIG_OPTPROBES
301 /*
302 * Internal structure for direct jump optimized probe
303 */
304 struct optimized_kprobe {
305 struct kprobe kp;
306 struct list_head list; /* list for optimizing queue */
307 struct arch_optimized_insn optinsn;
308 };
309
310 /* Architecture dependent functions for direct jump optimization */
311 extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
312 extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
313 extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op,
314 struct kprobe *orig);
315 extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
316 extern void arch_optimize_kprobes(struct list_head *oplist);
317 extern void arch_unoptimize_kprobes(struct list_head *oplist,
318 struct list_head *done_list);
319 extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
320 extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
321 unsigned long addr);
322
323 extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
324
325 DEFINE_INSN_CACHE_OPS(optinsn);
326
327 #ifdef CONFIG_SYSCTL
328 extern int sysctl_kprobes_optimization;
329 extern int proc_kprobes_optimization_handler(struct ctl_table *table,
330 int write, void __user *buffer,
331 size_t *length, loff_t *ppos);
332 #endif
333 extern void wait_for_kprobe_optimizer(void);
334 bool optprobe_queued_unopt(struct optimized_kprobe *op);
335 bool kprobe_disarmed(struct kprobe *p);
336 #else
wait_for_kprobe_optimizer(void)337 static inline void wait_for_kprobe_optimizer(void) { }
338 #endif /* CONFIG_OPTPROBES */
339 #ifdef CONFIG_KPROBES_ON_FTRACE
340 extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
341 struct ftrace_ops *ops, struct pt_regs *regs);
342 extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
343 #endif
344
345 int arch_check_ftrace_location(struct kprobe *p);
346
347 /* Get the kprobe at this addr (if any) - called with preemption disabled */
348 struct kprobe *get_kprobe(void *addr);
349 void kretprobe_hash_lock(struct task_struct *tsk,
350 struct hlist_head **head, unsigned long *flags);
351 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
352 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
353
354 /* kprobe_running() will just return the current_kprobe on this CPU */
kprobe_running(void)355 static inline struct kprobe *kprobe_running(void)
356 {
357 return (__this_cpu_read(current_kprobe));
358 }
359
reset_current_kprobe(void)360 static inline void reset_current_kprobe(void)
361 {
362 __this_cpu_write(current_kprobe, NULL);
363 }
364
get_kprobe_ctlblk(void)365 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
366 {
367 return this_cpu_ptr(&kprobe_ctlblk);
368 }
369
370 extern struct kprobe kprobe_busy;
371 void kprobe_busy_begin(void);
372 void kprobe_busy_end(void);
373
374 kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset);
375 int register_kprobe(struct kprobe *p);
376 void unregister_kprobe(struct kprobe *p);
377 int register_kprobes(struct kprobe **kps, int num);
378 void unregister_kprobes(struct kprobe **kps, int num);
379 unsigned long arch_deref_entry_point(void *);
380
381 int register_kretprobe(struct kretprobe *rp);
382 void unregister_kretprobe(struct kretprobe *rp);
383 int register_kretprobes(struct kretprobe **rps, int num);
384 void unregister_kretprobes(struct kretprobe **rps, int num);
385
386 void kprobe_flush_task(struct task_struct *tk);
387 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
388
389 int disable_kprobe(struct kprobe *kp);
390 int enable_kprobe(struct kprobe *kp);
391
392 void dump_kprobe(struct kprobe *kp);
393
394 #else /* !CONFIG_KPROBES: */
395
kprobes_built_in(void)396 static inline int kprobes_built_in(void)
397 {
398 return 0;
399 }
kprobe_fault_handler(struct pt_regs * regs,int trapnr)400 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
401 {
402 return 0;
403 }
get_kprobe(void * addr)404 static inline struct kprobe *get_kprobe(void *addr)
405 {
406 return NULL;
407 }
kprobe_running(void)408 static inline struct kprobe *kprobe_running(void)
409 {
410 return NULL;
411 }
register_kprobe(struct kprobe * p)412 static inline int register_kprobe(struct kprobe *p)
413 {
414 return -ENOSYS;
415 }
register_kprobes(struct kprobe ** kps,int num)416 static inline int register_kprobes(struct kprobe **kps, int num)
417 {
418 return -ENOSYS;
419 }
unregister_kprobe(struct kprobe * p)420 static inline void unregister_kprobe(struct kprobe *p)
421 {
422 }
unregister_kprobes(struct kprobe ** kps,int num)423 static inline void unregister_kprobes(struct kprobe **kps, int num)
424 {
425 }
register_kretprobe(struct kretprobe * rp)426 static inline int register_kretprobe(struct kretprobe *rp)
427 {
428 return -ENOSYS;
429 }
register_kretprobes(struct kretprobe ** rps,int num)430 static inline int register_kretprobes(struct kretprobe **rps, int num)
431 {
432 return -ENOSYS;
433 }
unregister_kretprobe(struct kretprobe * rp)434 static inline void unregister_kretprobe(struct kretprobe *rp)
435 {
436 }
unregister_kretprobes(struct kretprobe ** rps,int num)437 static inline void unregister_kretprobes(struct kretprobe **rps, int num)
438 {
439 }
kprobe_flush_task(struct task_struct * tk)440 static inline void kprobe_flush_task(struct task_struct *tk)
441 {
442 }
disable_kprobe(struct kprobe * kp)443 static inline int disable_kprobe(struct kprobe *kp)
444 {
445 return -ENOSYS;
446 }
enable_kprobe(struct kprobe * kp)447 static inline int enable_kprobe(struct kprobe *kp)
448 {
449 return -ENOSYS;
450 }
451 #endif /* CONFIG_KPROBES */
disable_kretprobe(struct kretprobe * rp)452 static inline int disable_kretprobe(struct kretprobe *rp)
453 {
454 return disable_kprobe(&rp->kp);
455 }
enable_kretprobe(struct kretprobe * rp)456 static inline int enable_kretprobe(struct kretprobe *rp)
457 {
458 return enable_kprobe(&rp->kp);
459 }
460
461 #ifndef CONFIG_KPROBES
is_kprobe_insn_slot(unsigned long addr)462 static inline bool is_kprobe_insn_slot(unsigned long addr)
463 {
464 return false;
465 }
466 #endif
467 #ifndef CONFIG_OPTPROBES
is_kprobe_optinsn_slot(unsigned long addr)468 static inline bool is_kprobe_optinsn_slot(unsigned long addr)
469 {
470 return false;
471 }
472 #endif
473
474 #endif /* _LINUX_KPROBES_H */
475