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