1 /*
2 * Kernel Probes (KProbes)
3 * kernel/kprobes.c
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 *
19 * Copyright (C) IBM Corporation, 2002, 2004
20 *
21 * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
22 * Probes initial implementation (includes suggestions from
23 * Rusty Russell).
24 * 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with
25 * hlists and exceptions notifier as suggested by Andi Kleen.
26 * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
27 * interface to access function arguments.
28 * 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes
29 * exceptions notifier to be first on the priority list.
30 * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston
31 * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
32 * <prasanna@in.ibm.com> added function-return probes.
33 */
34 #include <linux/kprobes.h>
35 #include <linux/hash.h>
36 #include <linux/init.h>
37 #include <linux/slab.h>
38 #include <linux/stddef.h>
39 #include <linux/export.h>
40 #include <linux/moduleloader.h>
41 #include <linux/kallsyms.h>
42 #include <linux/freezer.h>
43 #include <linux/seq_file.h>
44 #include <linux/debugfs.h>
45 #include <linux/sysctl.h>
46 #include <linux/kdebug.h>
47 #include <linux/memory.h>
48 #include <linux/ftrace.h>
49 #include <linux/cpu.h>
50 #include <linux/jump_label.h>
52 #include <asm-generic/sections.h>
53 #include <asm/cacheflush.h>
54 #include <asm/errno.h>
55 #include <asm/uaccess.h>
57 #define KPROBE_HASH_BITS 6
58 #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
61 /*
62 * Some oddball architectures like 64bit powerpc have function descriptors
63 * so this must be overridable.
64 */
65 #ifndef kprobe_lookup_name
66 #define kprobe_lookup_name(name, addr) \
67 addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name)))
68 #endif
70 static int kprobes_initialized;
71 static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
72 static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
74 /* NOTE: change this value only with kprobe_mutex held */
75 static bool kprobes_all_disarmed;
77 /* This protects kprobe_table and optimizing_list */
78 static DEFINE_MUTEX(kprobe_mutex);
79 static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
80 static struct {
81 raw_spinlock_t lock ____cacheline_aligned_in_smp;
82 } kretprobe_table_locks[KPROBE_TABLE_SIZE];
84 static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
85 {
86 return &(kretprobe_table_locks[hash].lock);
87 }
89 /*
90 * Normally, functions that we'd want to prohibit kprobes in, are marked
91 * __kprobes. But, there are cases where such functions already belong to
92 * a different section (__sched for preempt_schedule)
93 *
94 * For such cases, we now have a blacklist
95 */
96 static struct kprobe_blackpoint kprobe_blacklist[] = {
97 {"preempt_schedule",},
98 {"native_get_debugreg",},
99 {"irq_entries_start",},
100 {"common_interrupt",},
101 {"mcount",}, /* mcount can be called from everywhere */
102 {NULL} /* Terminator */
103 };
105 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
106 /*
107 * kprobe->ainsn.insn points to the copy of the instruction to be
108 * single-stepped. x86_64, POWER4 and above have no-exec support and
109 * stepping on the instruction on a vmalloced/kmalloced/data page
110 * is a recipe for disaster
111 */
112 struct kprobe_insn_page {
113 struct list_head list;
114 kprobe_opcode_t *insns; /* Page of instruction slots */
115 int nused;
116 int ngarbage;
117 char slot_used[];
118 };
120 #define KPROBE_INSN_PAGE_SIZE(slots) \
121 (offsetof(struct kprobe_insn_page, slot_used) + \
122 (sizeof(char) * (slots)))
124 struct kprobe_insn_cache {
125 struct list_head pages; /* list of kprobe_insn_page */
126 size_t insn_size; /* size of instruction slot */
127 int nr_garbage;
128 };
130 static int slots_per_page(struct kprobe_insn_cache *c)
131 {
132 return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t));
133 }
135 enum kprobe_slot_state {
136 SLOT_CLEAN = 0,
137 SLOT_DIRTY = 1,
138 SLOT_USED = 2,
139 };
141 static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_slots */
142 static struct kprobe_insn_cache kprobe_insn_slots = {
143 .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages),
144 .insn_size = MAX_INSN_SIZE,
145 .nr_garbage = 0,
146 };
147 static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c);
149 /**
150 * __get_insn_slot() - Find a slot on an executable page for an instruction.
151 * We allocate an executable page if there's no room on existing ones.
152 */
153 static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c)
154 {
155 struct kprobe_insn_page *kip;
157 retry:
158 list_for_each_entry(kip, &c->pages, list) {
159 if (kip->nused < slots_per_page(c)) {
160 int i;
161 for (i = 0; i < slots_per_page(c); i++) {
162 if (kip->slot_used[i] == SLOT_CLEAN) {
163 kip->slot_used[i] = SLOT_USED;
164 kip->nused++;
165 return kip->insns + (i * c->insn_size);
166 }
167 }
168 /* kip->nused is broken. Fix it. */
169 kip->nused = slots_per_page(c);
170 WARN_ON(1);
171 }
172 }
174 /* If there are any garbage slots, collect it and try again. */
175 if (c->nr_garbage && collect_garbage_slots(c) == 0)
176 goto retry;
178 /* All out of space. Need to allocate a new page. */
179 kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL);
180 if (!kip)
181 return NULL;
183 /*
184 * Use module_alloc so this page is within +/- 2GB of where the
185 * kernel image and loaded module images reside. This is required
186 * so x86_64 can correctly handle the %rip-relative fixups.
187 */
188 kip->insns = module_alloc(PAGE_SIZE);
189 if (!kip->insns) {
190 kfree(kip);
191 return NULL;
192 }
193 INIT_LIST_HEAD(&kip->list);
194 memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c));
195 kip->slot_used[0] = SLOT_USED;
196 kip->nused = 1;
197 kip->ngarbage = 0;
198 list_add(&kip->list, &c->pages);
199 return kip->insns;
200 }
203 kprobe_opcode_t __kprobes *get_insn_slot(void)
204 {
205 kprobe_opcode_t *ret = NULL;
207 mutex_lock(&kprobe_insn_mutex);
208 ret = __get_insn_slot(&kprobe_insn_slots);
209 mutex_unlock(&kprobe_insn_mutex);
211 return ret;
212 }
214 /* Return 1 if all garbages are collected, otherwise 0. */
215 static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
216 {
217 kip->slot_used[idx] = SLOT_CLEAN;
218 kip->nused--;
219 if (kip->nused == 0) {
220 /*
221 * Page is no longer in use. Free it unless
222 * it's the last one. We keep the last one
223 * so as not to have to set it up again the
224 * next time somebody inserts a probe.
225 */
226 if (!list_is_singular(&kip->list)) {
227 list_del(&kip->list);
228 module_free(NULL, kip->insns);
229 kfree(kip);
230 }
231 return 1;
232 }
233 return 0;
234 }
236 static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c)
237 {
238 struct kprobe_insn_page *kip, *next;
240 /* Ensure no-one is interrupted on the garbages */
241 synchronize_sched();
243 list_for_each_entry_safe(kip, next, &c->pages, list) {
244 int i;
245 if (kip->ngarbage == 0)
246 continue;
247 kip->ngarbage = 0; /* we will collect all garbages */
248 for (i = 0; i < slots_per_page(c); i++) {
249 if (kip->slot_used[i] == SLOT_DIRTY &&
250 collect_one_slot(kip, i))
251 break;
252 }
253 }
254 c->nr_garbage = 0;
255 return 0;
256 }
258 static void __kprobes __free_insn_slot(struct kprobe_insn_cache *c,
259 kprobe_opcode_t *slot, int dirty)
260 {
261 struct kprobe_insn_page *kip;
263 list_for_each_entry(kip, &c->pages, list) {
264 long idx = ((long)slot - (long)kip->insns) /
265 (c->insn_size * sizeof(kprobe_opcode_t));
266 if (idx >= 0 && idx < slots_per_page(c)) {
267 WARN_ON(kip->slot_used[idx] != SLOT_USED);
268 if (dirty) {
269 kip->slot_used[idx] = SLOT_DIRTY;
270 kip->ngarbage++;
271 if (++c->nr_garbage > slots_per_page(c))
272 collect_garbage_slots(c);
273 } else
274 collect_one_slot(kip, idx);
275 return;
276 }
277 }
278 /* Could not free this slot. */
279 WARN_ON(1);
280 }
282 void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
283 {
284 mutex_lock(&kprobe_insn_mutex);
285 __free_insn_slot(&kprobe_insn_slots, slot, dirty);
286 mutex_unlock(&kprobe_insn_mutex);
287 }
288 #ifdef CONFIG_OPTPROBES
289 /* For optimized_kprobe buffer */
290 static DEFINE_MUTEX(kprobe_optinsn_mutex); /* Protects kprobe_optinsn_slots */
291 static struct kprobe_insn_cache kprobe_optinsn_slots = {
292 .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
293 /* .insn_size is initialized later */
294 .nr_garbage = 0,
295 };
296 /* Get a slot for optimized_kprobe buffer */
297 kprobe_opcode_t __kprobes *get_optinsn_slot(void)
298 {
299 kprobe_opcode_t *ret = NULL;
301 mutex_lock(&kprobe_optinsn_mutex);
302 ret = __get_insn_slot(&kprobe_optinsn_slots);
303 mutex_unlock(&kprobe_optinsn_mutex);
305 return ret;
306 }
308 void __kprobes free_optinsn_slot(kprobe_opcode_t * slot, int dirty)
309 {
310 mutex_lock(&kprobe_optinsn_mutex);
311 __free_insn_slot(&kprobe_optinsn_slots, slot, dirty);
312 mutex_unlock(&kprobe_optinsn_mutex);
313 }
314 #endif
315 #endif
317 /* We have preemption disabled.. so it is safe to use __ versions */
318 static inline void set_kprobe_instance(struct kprobe *kp)
319 {
320 __this_cpu_write(kprobe_instance, kp);
321 }
323 static inline void reset_kprobe_instance(void)
324 {
325 __this_cpu_write(kprobe_instance, NULL);
326 }
328 /*
329 * This routine is called either:
330 * - under the kprobe_mutex - during kprobe_[un]register()
331 * OR
332 * - with preemption disabled - from arch/xxx/kernel/kprobes.c
333 */
334 struct kprobe __kprobes *get_kprobe(void *addr)
335 {
336 struct hlist_head *head;
337 struct hlist_node *node;
338 struct kprobe *p;
340 head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
341 hlist_for_each_entry_rcu(p, node, head, hlist) {
342 if (p->addr == addr)
343 return p;
344 }
346 return NULL;
347 }
349 static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs);
351 /* Return true if the kprobe is an aggregator */
352 static inline int kprobe_aggrprobe(struct kprobe *p)
353 {
354 return p->pre_handler == aggr_pre_handler;
355 }
357 /* Return true(!0) if the kprobe is unused */
358 static inline int kprobe_unused(struct kprobe *p)
359 {
360 return kprobe_aggrprobe(p) && kprobe_disabled(p) &&
361 list_empty(&p->list);
362 }
364 /*
365 * Keep all fields in the kprobe consistent
366 */
367 static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p)
368 {
369 memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t));
370 memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn));
371 }
373 #ifdef CONFIG_OPTPROBES
374 /* NOTE: change this value only with kprobe_mutex held */
375 static bool kprobes_allow_optimization;
377 /*
378 * Call all pre_handler on the list, but ignores its return value.
379 * This must be called from arch-dep optimized caller.
380 */
381 void __kprobes opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
382 {
383 struct kprobe *kp;
385 list_for_each_entry_rcu(kp, &p->list, list) {
386 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
387 set_kprobe_instance(kp);
388 kp->pre_handler(kp, regs);
389 }
390 reset_kprobe_instance();
391 }
392 }
394 /* Free optimized instructions and optimized_kprobe */
395 static __kprobes void free_aggr_kprobe(struct kprobe *p)
396 {
397 struct optimized_kprobe *op;
399 op = container_of(p, struct optimized_kprobe, kp);
400 arch_remove_optimized_kprobe(op);
401 arch_remove_kprobe(p);
402 kfree(op);
403 }
405 /* Return true(!0) if the kprobe is ready for optimization. */
406 static inline int kprobe_optready(struct kprobe *p)
407 {
408 struct optimized_kprobe *op;
410 if (kprobe_aggrprobe(p)) {
411 op = container_of(p, struct optimized_kprobe, kp);
412 return arch_prepared_optinsn(&op->optinsn);
413 }
415 return 0;
416 }
418 /* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */
419 static inline int kprobe_disarmed(struct kprobe *p)
420 {
421 struct optimized_kprobe *op;
423 /* If kprobe is not aggr/opt probe, just return kprobe is disabled */
424 if (!kprobe_aggrprobe(p))
425 return kprobe_disabled(p);
427 op = container_of(p, struct optimized_kprobe, kp);
429 return kprobe_disabled(p) && list_empty(&op->list);
430 }
432 /* Return true(!0) if the probe is queued on (un)optimizing lists */
433 static int __kprobes kprobe_queued(struct kprobe *p)
434 {
435 struct optimized_kprobe *op;
437 if (kprobe_aggrprobe(p)) {
438 op = container_of(p, struct optimized_kprobe, kp);
439 if (!list_empty(&op->list))
440 return 1;
441 }
442 return 0;
443 }
445 /*
446 * Return an optimized kprobe whose optimizing code replaces
447 * instructions including addr (exclude breakpoint).
448 */
449 static struct kprobe *__kprobes get_optimized_kprobe(unsigned long addr)
450 {
451 int i;
452 struct kprobe *p = NULL;
453 struct optimized_kprobe *op;
455 /* Don't check i == 0, since that is a breakpoint case. */
456 for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++)
457 p = get_kprobe((void *)(addr - i));
459 if (p && kprobe_optready(p)) {
460 op = container_of(p, struct optimized_kprobe, kp);
461 if (arch_within_optimized_kprobe(op, addr))
462 return p;
463 }
465 return NULL;
466 }
468 /* Optimization staging list, protected by kprobe_mutex */
469 static LIST_HEAD(optimizing_list);
470 static LIST_HEAD(unoptimizing_list);
472 static void kprobe_optimizer(struct work_struct *work);
473 static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
474 static DECLARE_COMPLETION(optimizer_comp);
475 #define OPTIMIZE_DELAY 5
477 /*
478 * Optimize (replace a breakpoint with a jump) kprobes listed on
479 * optimizing_list.
480 */
481 static __kprobes void do_optimize_kprobes(void)
482 {
483 /* Optimization never be done when disarmed */
484 if (kprobes_all_disarmed || !kprobes_allow_optimization ||
485 list_empty(&optimizing_list))
486 return;
488 /*
489 * The optimization/unoptimization refers online_cpus via
490 * stop_machine() and cpu-hotplug modifies online_cpus.
491 * And same time, text_mutex will be held in cpu-hotplug and here.
492 * This combination can cause a deadlock (cpu-hotplug try to lock
493 * text_mutex but stop_machine can not be done because online_cpus
494 * has been changed)
495 * To avoid this deadlock, we need to call get_online_cpus()
496 * for preventing cpu-hotplug outside of text_mutex locking.
497 */
498 get_online_cpus();
499 mutex_lock(&text_mutex);
500 arch_optimize_kprobes(&optimizing_list);
501 mutex_unlock(&text_mutex);
502 put_online_cpus();
503 }
505 /*
506 * Unoptimize (replace a jump with a breakpoint and remove the breakpoint
507 * if need) kprobes listed on unoptimizing_list.
508 */
509 static __kprobes void do_unoptimize_kprobes(struct list_head *free_list)
510 {
511 struct optimized_kprobe *op, *tmp;
513 /* Unoptimization must be done anytime */
514 if (list_empty(&unoptimizing_list))
515 return;
517 /* Ditto to do_optimize_kprobes */
518 get_online_cpus();
519 mutex_lock(&text_mutex);
520 arch_unoptimize_kprobes(&unoptimizing_list, free_list);
521 /* Loop free_list for disarming */
522 list_for_each_entry_safe(op, tmp, free_list, list) {
523 /* Disarm probes if marked disabled */
524 if (kprobe_disabled(&op->kp))
525 arch_disarm_kprobe(&op->kp);
526 if (kprobe_unused(&op->kp)) {
527 /*
528 * Remove unused probes from hash list. After waiting
529 * for synchronization, these probes are reclaimed.
530 * (reclaiming is done by do_free_cleaned_kprobes.)
531 */
532 hlist_del_rcu(&op->kp.hlist);
533 } else
534 list_del_init(&op->list);
535 }
536 mutex_unlock(&text_mutex);
537 put_online_cpus();
538 }
540 /* Reclaim all kprobes on the free_list */
541 static __kprobes void do_free_cleaned_kprobes(struct list_head *free_list)
542 {
543 struct optimized_kprobe *op, *tmp;
545 list_for_each_entry_safe(op, tmp, free_list, list) {
546 BUG_ON(!kprobe_unused(&op->kp));
547 list_del_init(&op->list);
548 free_aggr_kprobe(&op->kp);
549 }
550 }
552 /* Start optimizer after OPTIMIZE_DELAY passed */
553 static __kprobes void kick_kprobe_optimizer(void)
554 {
555 if (!delayed_work_pending(&optimizing_work))
556 schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
557 }
559 /* Kprobe jump optimizer */
560 static __kprobes void kprobe_optimizer(struct work_struct *work)
561 {
562 LIST_HEAD(free_list);
564 /* Lock modules while optimizing kprobes */
565 mutex_lock(&module_mutex);
566 mutex_lock(&kprobe_mutex);
568 /*
569 * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
570 * kprobes before waiting for quiesence period.
571 */
572 do_unoptimize_kprobes(&free_list);
574 /*
575 * Step 2: Wait for quiesence period to ensure all running interrupts
576 * are done. Because optprobe may modify multiple instructions
577 * there is a chance that Nth instruction is interrupted. In that
578 * case, running interrupt can return to 2nd-Nth byte of jump
579 * instruction. This wait is for avoiding it.
580 */
581 synchronize_sched();
583 /* Step 3: Optimize kprobes after quiesence period */
584 do_optimize_kprobes();
586 /* Step 4: Free cleaned kprobes after quiesence period */
587 do_free_cleaned_kprobes(&free_list);
589 mutex_unlock(&kprobe_mutex);
590 mutex_unlock(&module_mutex);
592 /* Step 5: Kick optimizer again if needed */
593 if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
594 kick_kprobe_optimizer();
595 else
596 /* Wake up all waiters */
597 complete_all(&optimizer_comp);
598 }
600 /* Wait for completing optimization and unoptimization */
601 static __kprobes void wait_for_kprobe_optimizer(void)
602 {
603 if (delayed_work_pending(&optimizing_work))
604 wait_for_completion(&optimizer_comp);
605 }
607 /* Optimize kprobe if p is ready to be optimized */
608 static __kprobes void optimize_kprobe(struct kprobe *p)
609 {
610 struct optimized_kprobe *op;
612 /* Check if the kprobe is disabled or not ready for optimization. */
613 if (!kprobe_optready(p) || !kprobes_allow_optimization ||
614 (kprobe_disabled(p) || kprobes_all_disarmed))
615 return;
617 /* Both of break_handler and post_handler are not supported. */
618 if (p->break_handler || p->post_handler)
619 return;
621 op = container_of(p, struct optimized_kprobe, kp);
623 /* Check there is no other kprobes at the optimized instructions */
624 if (arch_check_optimized_kprobe(op) < 0)
625 return;
627 /* Check if it is already optimized. */
628 if (op->kp.flags & KPROBE_FLAG_OPTIMIZED)
629 return;
630 op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
632 if (!list_empty(&op->list))
633 /* This is under unoptimizing. Just dequeue the probe */
634 list_del_init(&op->list);
635 else {
636 list_add(&op->list, &optimizing_list);
637 kick_kprobe_optimizer();
638 }
639 }
641 /* Short cut to direct unoptimizing */
642 static __kprobes void force_unoptimize_kprobe(struct optimized_kprobe *op)
643 {
644 get_online_cpus();
645 arch_unoptimize_kprobe(op);
646 put_online_cpus();
647 if (kprobe_disabled(&op->kp))
648 arch_disarm_kprobe(&op->kp);
649 }
651 /* Unoptimize a kprobe if p is optimized */
652 static __kprobes void unoptimize_kprobe(struct kprobe *p, bool force)
653 {
654 struct optimized_kprobe *op;
656 if (!kprobe_aggrprobe(p) || kprobe_disarmed(p))
657 return; /* This is not an optprobe nor optimized */
659 op = container_of(p, struct optimized_kprobe, kp);
660 if (!kprobe_optimized(p)) {
661 /* Unoptimized or unoptimizing case */
662 if (force && !list_empty(&op->list)) {
663 /*
664 * Only if this is unoptimizing kprobe and forced,
665 * forcibly unoptimize it. (No need to unoptimize
666 * unoptimized kprobe again :)
667 */
668 list_del_init(&op->list);
669 force_unoptimize_kprobe(op);
670 }
671 return;
672 }
674 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
675 if (!list_empty(&op->list)) {
676 /* Dequeue from the optimization queue */
677 list_del_init(&op->list);
678 return;
679 }
680 /* Optimized kprobe case */
681 if (force)
682 /* Forcibly update the code: this is a special case */
683 force_unoptimize_kprobe(op);
684 else {
685 list_add(&op->list, &unoptimizing_list);
686 kick_kprobe_optimizer();
687 }
688 }
690 /* Cancel unoptimizing for reusing */
691 static void reuse_unused_kprobe(struct kprobe *ap)
692 {
693 struct optimized_kprobe *op;
695 BUG_ON(!kprobe_unused(ap));
696 /*
697 * Unused kprobe MUST be on the way of delayed unoptimizing (means
698 * there is still a relative jump) and disabled.
699 */
700 op = container_of(ap, struct optimized_kprobe, kp);
701 if (unlikely(list_empty(&op->list)))
702 printk(KERN_WARNING "Warning: found a stray unused "
703 "aggrprobe@%p\n", ap->addr);
704 /* Enable the probe again */
705 ap->flags &= ~KPROBE_FLAG_DISABLED;
706 /* Optimize it again (remove from op->list) */
707 BUG_ON(!kprobe_optready(ap));
708 optimize_kprobe(ap);
709 }
711 /* Remove optimized instructions */
712 static void __kprobes kill_optimized_kprobe(struct kprobe *p)
713 {
714 struct optimized_kprobe *op;
716 op = container_of(p, struct optimized_kprobe, kp);
717 if (!list_empty(&op->list))
718 /* Dequeue from the (un)optimization queue */
719 list_del_init(&op->list);
721 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
722 /* Don't touch the code, because it is already freed. */
723 arch_remove_optimized_kprobe(op);
724 }
726 /* Try to prepare optimized instructions */
727 static __kprobes void prepare_optimized_kprobe(struct kprobe *p)
728 {
729 struct optimized_kprobe *op;
731 op = container_of(p, struct optimized_kprobe, kp);
732 arch_prepare_optimized_kprobe(op);
733 }
735 /* Allocate new optimized_kprobe and try to prepare optimized instructions */
736 static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
737 {
738 struct optimized_kprobe *op;
740 op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL);
741 if (!op)
742 return NULL;
744 INIT_LIST_HEAD(&op->list);
745 op->kp.addr = p->addr;
746 arch_prepare_optimized_kprobe(op);
748 return &op->kp;
749 }
751 static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p);
753 /*
754 * Prepare an optimized_kprobe and optimize it
755 * NOTE: p must be a normal registered kprobe
756 */
757 static __kprobes void try_to_optimize_kprobe(struct kprobe *p)
758 {
759 struct kprobe *ap;
760 struct optimized_kprobe *op;
762 ap = alloc_aggr_kprobe(p);
763 if (!ap)
764 return;
766 op = container_of(ap, struct optimized_kprobe, kp);
767 if (!arch_prepared_optinsn(&op->optinsn)) {
768 /* If failed to setup optimizing, fallback to kprobe */
769 arch_remove_optimized_kprobe(op);
770 kfree(op);
771 return;
772 }
774 init_aggr_kprobe(ap, p);
775 optimize_kprobe(ap);
776 }
778 #ifdef CONFIG_SYSCTL
779 /* This should be called with kprobe_mutex locked */
780 static void __kprobes optimize_all_kprobes(void)
781 {
782 struct hlist_head *head;
783 struct hlist_node *node;
784 struct kprobe *p;
785 unsigned int i;
787 /* If optimization is already allowed, just return */
788 if (kprobes_allow_optimization)
789 return;
791 kprobes_allow_optimization = true;
792 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
793 head = &kprobe_table[i];
794 hlist_for_each_entry_rcu(p, node, head, hlist)
795 if (!kprobe_disabled(p))
796 optimize_kprobe(p);
797 }
798 printk(KERN_INFO "Kprobes globally optimized\n");
799 }
801 /* This should be called with kprobe_mutex locked */
802 static void __kprobes unoptimize_all_kprobes(void)
803 {
804 struct hlist_head *head;
805 struct hlist_node *node;
806 struct kprobe *p;
807 unsigned int i;
809 /* If optimization is already prohibited, just return */
810 if (!kprobes_allow_optimization)
811 return;
813 kprobes_allow_optimization = false;
814 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
815 head = &kprobe_table[i];
816 hlist_for_each_entry_rcu(p, node, head, hlist) {
817 if (!kprobe_disabled(p))
818 unoptimize_kprobe(p, false);
819 }
820 }
821 /* Wait for unoptimizing completion */
822 wait_for_kprobe_optimizer();
823 printk(KERN_INFO "Kprobes globally unoptimized\n");
824 }
826 int sysctl_kprobes_optimization;
827 int proc_kprobes_optimization_handler(struct ctl_table *table, int write,
828 void __user *buffer, size_t *length,
829 loff_t *ppos)
830 {
831 int ret;
833 mutex_lock(&kprobe_mutex);
834 sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0;
835 ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
837 if (sysctl_kprobes_optimization)
838 optimize_all_kprobes();
839 else
840 unoptimize_all_kprobes();
841 mutex_unlock(&kprobe_mutex);
843 return ret;
844 }
845 #endif /* CONFIG_SYSCTL */
847 /* Put a breakpoint for a probe. Must be called with text_mutex locked */
848 static void __kprobes __arm_kprobe(struct kprobe *p)
849 {
850 struct kprobe *_p;
852 /* Check collision with other optimized kprobes */
853 _p = get_optimized_kprobe((unsigned long)p->addr);
854 if (unlikely(_p))
855 /* Fallback to unoptimized kprobe */
856 unoptimize_kprobe(_p, true);
858 arch_arm_kprobe(p);
859 optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */
860 }
862 /* Remove the breakpoint of a probe. Must be called with text_mutex locked */
863 static void __kprobes __disarm_kprobe(struct kprobe *p, bool reopt)
864 {
865 struct kprobe *_p;
867 unoptimize_kprobe(p, false); /* Try to unoptimize */
869 if (!kprobe_queued(p)) {
870 arch_disarm_kprobe(p);
871 /* If another kprobe was blocked, optimize it. */
872 _p = get_optimized_kprobe((unsigned long)p->addr);
873 if (unlikely(_p) && reopt)
874 optimize_kprobe(_p);
875 }
876 /* TODO: reoptimize others after unoptimized this probe */
877 }
879 #else /* !CONFIG_OPTPROBES */
881 #define optimize_kprobe(p) do {} while (0)
882 #define unoptimize_kprobe(p, f) do {} while (0)
883 #define kill_optimized_kprobe(p) do {} while (0)
884 #define prepare_optimized_kprobe(p) do {} while (0)
885 #define try_to_optimize_kprobe(p) do {} while (0)
886 #define __arm_kprobe(p) arch_arm_kprobe(p)
887 #define __disarm_kprobe(p, o) arch_disarm_kprobe(p)
888 #define kprobe_disarmed(p) kprobe_disabled(p)
889 #define wait_for_kprobe_optimizer() do {} while (0)
891 /* There should be no unused kprobes can be reused without optimization */
892 static void reuse_unused_kprobe(struct kprobe *ap)
893 {
894 printk(KERN_ERR "Error: There should be no unused kprobe here.\n");
895 BUG_ON(kprobe_unused(ap));
896 }
898 static __kprobes void free_aggr_kprobe(struct kprobe *p)
899 {
900 arch_remove_kprobe(p);
901 kfree(p);
902 }
904 static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
905 {
906 return kzalloc(sizeof(struct kprobe), GFP_KERNEL);
907 }
908 #endif /* CONFIG_OPTPROBES */
910 /* Arm a kprobe with text_mutex */
911 static void __kprobes arm_kprobe(struct kprobe *kp)
912 {
913 /*
914 * Here, since __arm_kprobe() doesn't use stop_machine(),
915 * this doesn't cause deadlock on text_mutex. So, we don't
916 * need get_online_cpus().
917 */
918 mutex_lock(&text_mutex);
919 __arm_kprobe(kp);
920 mutex_unlock(&text_mutex);
921 }
923 /* Disarm a kprobe with text_mutex */
924 static void __kprobes disarm_kprobe(struct kprobe *kp)
925 {
926 /* Ditto */
927 mutex_lock(&text_mutex);
928 __disarm_kprobe(kp, true);
929 mutex_unlock(&text_mutex);
930 }
932 /*
933 * Aggregate handlers for multiple kprobes support - these handlers
934 * take care of invoking the individual kprobe handlers on p->list
935 */
936 static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
937 {
938 struct kprobe *kp;
940 list_for_each_entry_rcu(kp, &p->list, list) {
941 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
942 set_kprobe_instance(kp);
943 if (kp->pre_handler(kp, regs))
944 return 1;
945 }
946 reset_kprobe_instance();
947 }
948 return 0;
949 }
951 static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
952 unsigned long flags)
953 {
954 struct kprobe *kp;
956 list_for_each_entry_rcu(kp, &p->list, list) {
957 if (kp->post_handler && likely(!kprobe_disabled(kp))) {
958 set_kprobe_instance(kp);
959 kp->post_handler(kp, regs, flags);
960 reset_kprobe_instance();
961 }
962 }
963 }
965 static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
966 int trapnr)
967 {
968 struct kprobe *cur = __this_cpu_read(kprobe_instance);
970 /*
971 * if we faulted "during" the execution of a user specified
972 * probe handler, invoke just that probe's fault handler
973 */
974 if (cur && cur->fault_handler) {
975 if (cur->fault_handler(cur, regs, trapnr))
976 return 1;
977 }
978 return 0;
979 }
981 static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
982 {
983 struct kprobe *cur = __this_cpu_read(kprobe_instance);
984 int ret = 0;
986 if (cur && cur->break_handler) {
987 if (cur->break_handler(cur, regs))
988 ret = 1;
989 }
990 reset_kprobe_instance();
991 return ret;
992 }
994 /* Walks the list and increments nmissed count for multiprobe case */
995 void __kprobes kprobes_inc_nmissed_count(struct kprobe *p)
996 {
997 struct kprobe *kp;
998 if (!kprobe_aggrprobe(p)) {
999 p->nmissed++;
1000 } else {
1001 list_for_each_entry_rcu(kp, &p->list, list)
1002 kp->nmissed++;
1003 }
1004 return;
1005 }
1007 void __kprobes recycle_rp_inst(struct kretprobe_instance *ri,
1008 struct hlist_head *head)
1009 {
1010 struct kretprobe *rp = ri->rp;
1012 /* remove rp inst off the rprobe_inst_table */
1013 hlist_del(&ri->hlist);
1014 INIT_HLIST_NODE(&ri->hlist);
1015 if (likely(rp)) {
1016 raw_spin_lock(&rp->lock);
1017 hlist_add_head(&ri->hlist, &rp->free_instances);
1018 raw_spin_unlock(&rp->lock);
1019 } else
1020 /* Unregistering */
1021 hlist_add_head(&ri->hlist, head);
1022 }
1024 void __kprobes kretprobe_hash_lock(struct task_struct *tsk,
1025 struct hlist_head **head, unsigned long *flags)
1026 __acquires(hlist_lock)
1027 {
1028 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
1029 raw_spinlock_t *hlist_lock;
1031 *head = &kretprobe_inst_table[hash];
1032 hlist_lock = kretprobe_table_lock_ptr(hash);
1033 raw_spin_lock_irqsave(hlist_lock, *flags);
1034 }
1036 static void __kprobes kretprobe_table_lock(unsigned long hash,
1037 unsigned long *flags)
1038 __acquires(hlist_lock)
1039 {
1040 raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
1041 raw_spin_lock_irqsave(hlist_lock, *flags);
1042 }
1044 void __kprobes kretprobe_hash_unlock(struct task_struct *tsk,
1045 unsigned long *flags)
1046 __releases(hlist_lock)
1047 {
1048 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
1049 raw_spinlock_t *hlist_lock;
1051 hlist_lock = kretprobe_table_lock_ptr(hash);
1052 raw_spin_unlock_irqrestore(hlist_lock, *flags);
1053 }
1055 static void __kprobes kretprobe_table_unlock(unsigned long hash,
1056 unsigned long *flags)
1057 __releases(hlist_lock)
1058 {
1059 raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
1060 raw_spin_unlock_irqrestore(hlist_lock, *flags);
1061 }
1063 /*
1064 * This function is called from finish_task_switch when task tk becomes dead,
1065 * so that we can recycle any function-return probe instances associated
1066 * with this task. These left over instances represent probed functions
1067 * that have been called but will never return.
1068 */
1069 void __kprobes kprobe_flush_task(struct task_struct *tk)
1070 {
1071 struct kretprobe_instance *ri;
1072 struct hlist_head *head, empty_rp;
1073 struct hlist_node *node, *tmp;
1074 unsigned long hash, flags = 0;
1076 if (unlikely(!kprobes_initialized))
1077 /* Early boot. kretprobe_table_locks not yet initialized. */
1078 return;
1080 hash = hash_ptr(tk, KPROBE_HASH_BITS);
1081 head = &kretprobe_inst_table[hash];
1082 kretprobe_table_lock(hash, &flags);
1083 hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
1084 if (ri->task == tk)
1085 recycle_rp_inst(ri, &empty_rp);
1086 }
1087 kretprobe_table_unlock(hash, &flags);
1088 INIT_HLIST_HEAD(&empty_rp);
1089 hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
1090 hlist_del(&ri->hlist);
1091 kfree(ri);
1092 }
1093 }
1095 static inline void free_rp_inst(struct kretprobe *rp)
1096 {
1097 struct kretprobe_instance *ri;
1098 struct hlist_node *pos, *next;
1100 hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) {
1101 hlist_del(&ri->hlist);
1102 kfree(ri);
1103 }
1104 }
1106 static void __kprobes cleanup_rp_inst(struct kretprobe *rp)
1107 {
1108 unsigned long flags, hash;
1109 struct kretprobe_instance *ri;
1110 struct hlist_node *pos, *next;
1111 struct hlist_head *head;
1113 /* No race here */
1114 for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) {
1115 kretprobe_table_lock(hash, &flags);
1116 head = &kretprobe_inst_table[hash];
1117 hlist_for_each_entry_safe(ri, pos, next, head, hlist) {
1118 if (ri->rp == rp)
1119 ri->rp = NULL;
1120 }
1121 kretprobe_table_unlock(hash, &flags);
1122 }
1123 free_rp_inst(rp);
1124 }
1126 /*
1127 * Add the new probe to ap->list. Fail if this is the
1128 * second jprobe at the address - two jprobes can't coexist
1129 */
1130 static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p)
1131 {
1132 BUG_ON(kprobe_gone(ap) || kprobe_gone(p));
1134 if (p->break_handler || p->post_handler)
1135 unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */
1137 if (p->break_handler) {
1138 if (ap->break_handler)
1139 return -EEXIST;
1140 list_add_tail_rcu(&p->list, &ap->list);
1141 ap->break_handler = aggr_break_handler;
1142 } else
1143 list_add_rcu(&p->list, &ap->list);
1144 if (p->post_handler && !ap->post_handler)
1145 ap->post_handler = aggr_post_handler;
1147 if (kprobe_disabled(ap) && !kprobe_disabled(p)) {
1148 ap->flags &= ~KPROBE_FLAG_DISABLED;
1149 if (!kprobes_all_disarmed)
1150 /* Arm the breakpoint again. */
1151 __arm_kprobe(ap);
1152 }
1153 return 0;
1154 }
1156 /*
1157 * Fill in the required fields of the "manager kprobe". Replace the
1158 * earlier kprobe in the hlist with the manager kprobe
1159 */
1160 static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
1161 {
1162 /* Copy p's insn slot to ap */
1163 copy_kprobe(p, ap);
1164 flush_insn_slot(ap);
1165 ap->addr = p->addr;
1166 ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED;
1167 ap->pre_handler = aggr_pre_handler;
1168 ap->fault_handler = aggr_fault_handler;
1169 /* We don't care the kprobe which has gone. */
1170 if (p->post_handler && !kprobe_gone(p))
1171 ap->post_handler = aggr_post_handler;
1172 if (p->break_handler && !kprobe_gone(p))
1173 ap->break_handler = aggr_break_handler;
1175 INIT_LIST_HEAD(&ap->list);
1176 INIT_HLIST_NODE(&ap->hlist);
1178 list_add_rcu(&p->list, &ap->list);
1179 hlist_replace_rcu(&p->hlist, &ap->hlist);
1180 }
1182 /*
1183 * This is the second or subsequent kprobe at the address - handle
1184 * the intricacies
1185 */
1186 static int __kprobes register_aggr_kprobe(struct kprobe *orig_p,
1187 struct kprobe *p)
1188 {
1189 int ret = 0;
1190 struct kprobe *ap = orig_p;
1192 if (!kprobe_aggrprobe(orig_p)) {
1193 /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */
1194 ap = alloc_aggr_kprobe(orig_p);
1195 if (!ap)
1196 return -ENOMEM;
1197 init_aggr_kprobe(ap, orig_p);
1198 } else if (kprobe_unused(ap))
1199 /* This probe is going to die. Rescue it */
1200 reuse_unused_kprobe(ap);
1202 if (kprobe_gone(ap)) {
1203 /*
1204 * Attempting to insert new probe at the same location that
1205 * had a probe in the module vaddr area which already
1206 * freed. So, the instruction slot has already been
1207 * released. We need a new slot for the new probe.
1208 */
1209 ret = arch_prepare_kprobe(ap);
1210 if (ret)
1211 /*
1212 * Even if fail to allocate new slot, don't need to
1213 * free aggr_probe. It will be used next time, or
1214 * freed by unregister_kprobe.
1215 */
1216 return ret;
1218 /* Prepare optimized instructions if possible. */
1219 prepare_optimized_kprobe(ap);
1221 /*
1222 * Clear gone flag to prevent allocating new slot again, and
1223 * set disabled flag because it is not armed yet.
1224 */
1225 ap->flags = (ap->flags & ~KPROBE_FLAG_GONE)
1226 | KPROBE_FLAG_DISABLED;
1227 }
1229 /* Copy ap's insn slot to p */
1230 copy_kprobe(ap, p);
1231 return add_new_kprobe(ap, p);
1232 }
1234 static int __kprobes in_kprobes_functions(unsigned long addr)
1235 {
1236 struct kprobe_blackpoint *kb;
1238 if (addr >= (unsigned long)__kprobes_text_start &&
1239 addr < (unsigned long)__kprobes_text_end)
1240 return -EINVAL;
1241 /*
1242 * If there exists a kprobe_blacklist, verify and
1243 * fail any probe registration in the prohibited area
1244 */
1245 for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
1246 if (kb->start_addr) {
1247 if (addr >= kb->start_addr &&
1248 addr < (kb->start_addr + kb->range))
1249 return -EINVAL;
1250 }
1251 }
1252 return 0;
1253 }
1255 /*
1256 * If we have a symbol_name argument, look it up and add the offset field
1257 * to it. This way, we can specify a relative address to a symbol.
1258 * This returns encoded errors if it fails to look up symbol or invalid
1259 * combination of parameters.
1260 */
1261 static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p)
1262 {
1263 kprobe_opcode_t *addr = p->addr;
1265 if ((p->symbol_name && p->addr) ||
1266 (!p->symbol_name && !p->addr))
1267 goto invalid;
1269 if (p->symbol_name) {
1270 kprobe_lookup_name(p->symbol_name, addr);
1271 if (!addr)
1272 return ERR_PTR(-ENOENT);
1273 }
1275 addr = (kprobe_opcode_t *)(((char *)addr) + p->offset);
1276 if (addr)
1277 return addr;
1279 invalid:
1280 return ERR_PTR(-EINVAL);
1281 }
1283 /* Check passed kprobe is valid and return kprobe in kprobe_table. */
1284 static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p)
1285 {
1286 struct kprobe *ap, *list_p;
1288 ap = get_kprobe(p->addr);
1289 if (unlikely(!ap))
1290 return NULL;
1292 if (p != ap) {
1293 list_for_each_entry_rcu(list_p, &ap->list, list)
1294 if (list_p == p)
1295 /* kprobe p is a valid probe */
1296 goto valid;
1297 return NULL;
1298 }
1299 valid:
1300 return ap;
1301 }
1303 /* Return error if the kprobe is being re-registered */
1304 static inline int check_kprobe_rereg(struct kprobe *p)
1305 {
1306 int ret = 0;
1308 mutex_lock(&kprobe_mutex);
1309 if (__get_valid_kprobe(p))
1310 ret = -EINVAL;
1311 mutex_unlock(&kprobe_mutex);
1313 return ret;
1314 }
1316 int __kprobes register_kprobe(struct kprobe *p)
1317 {
1318 int ret = 0;
1319 struct kprobe *old_p;
1320 struct module *probed_mod;
1321 kprobe_opcode_t *addr;
1323 addr = kprobe_addr(p);
1324 if (IS_ERR(addr))
1325 return PTR_ERR(addr);
1326 p->addr = addr;
1328 ret = check_kprobe_rereg(p);
1329 if (ret)
1330 return ret;
1332 jump_label_lock();
1333 preempt_disable();
1334 if (!kernel_text_address((unsigned long) p->addr) ||
1335 in_kprobes_functions((unsigned long) p->addr) ||
1336 ftrace_text_reserved(p->addr, p->addr) ||
1337 jump_label_text_reserved(p->addr, p->addr))
1338 goto fail_with_jump_label;
1340 /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
1341 p->flags &= KPROBE_FLAG_DISABLED;
1343 /*
1344 * Check if are we probing a module.
1345 */
1346 probed_mod = __module_text_address((unsigned long) p->addr);
1347 if (probed_mod) {
1348 /* Return -ENOENT if fail. */
1349 ret = -ENOENT;
1350 /*
1351 * We must hold a refcount of the probed module while updating
1352 * its code to prohibit unexpected unloading.
1353 */
1354 if (unlikely(!try_module_get(probed_mod)))
1355 goto fail_with_jump_label;
1357 /*
1358 * If the module freed .init.text, we couldn't insert
1359 * kprobes in there.
1360 */
1361 if (within_module_init((unsigned long)p->addr, probed_mod) &&
1362 probed_mod->state != MODULE_STATE_COMING) {
1363 module_put(probed_mod);
1364 goto fail_with_jump_label;
1365 }
1366 /* ret will be updated by following code */
1367 }
1368 preempt_enable();
1369 jump_label_unlock();
1371 p->nmissed = 0;
1372 INIT_LIST_HEAD(&p->list);
1373 mutex_lock(&kprobe_mutex);
1375 jump_label_lock(); /* needed to call jump_label_text_reserved() */
1377 get_online_cpus(); /* For avoiding text_mutex deadlock. */
1378 mutex_lock(&text_mutex);
1380 old_p = get_kprobe(p->addr);
1381 if (old_p) {
1382 /* Since this may unoptimize old_p, locking text_mutex. */
1383 ret = register_aggr_kprobe(old_p, p);
1384 goto out;
1385 }
1387 ret = arch_prepare_kprobe(p);
1388 if (ret)
1389 goto out;
1391 INIT_HLIST_NODE(&p->hlist);
1392 hlist_add_head_rcu(&p->hlist,
1393 &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
1395 if (!kprobes_all_disarmed && !kprobe_disabled(p))
1396 __arm_kprobe(p);
1398 /* Try to optimize kprobe */
1399 try_to_optimize_kprobe(p);
1401 out:
1402 mutex_unlock(&text_mutex);
1403 put_online_cpus();
1404 jump_label_unlock();
1405 mutex_unlock(&kprobe_mutex);
1407 if (probed_mod)
1408 module_put(probed_mod);
1410 return ret;
1412 fail_with_jump_label:
1413 preempt_enable();
1414 jump_label_unlock();
1415 return ret;
1416 }
1417 EXPORT_SYMBOL_GPL(register_kprobe);
1419 /* Check if all probes on the aggrprobe are disabled */
1420 static int __kprobes aggr_kprobe_disabled(struct kprobe *ap)
1421 {
1422 struct kprobe *kp;
1424 list_for_each_entry_rcu(kp, &ap->list, list)
1425 if (!kprobe_disabled(kp))
1426 /*
1427 * There is an active probe on the list.
1428 * We can't disable this ap.
1429 */
1430 return 0;
1432 return 1;
1433 }
1435 /* Disable one kprobe: Make sure called under kprobe_mutex is locked */
1436 static struct kprobe *__kprobes __disable_kprobe(struct kprobe *p)
1437 {
1438 struct kprobe *orig_p;
1440 /* Get an original kprobe for return */
1441 orig_p = __get_valid_kprobe(p);
1442 if (unlikely(orig_p == NULL))
1443 return NULL;
1445 if (!kprobe_disabled(p)) {
1446 /* Disable probe if it is a child probe */
1447 if (p != orig_p)
1448 p->flags |= KPROBE_FLAG_DISABLED;
1450 /* Try to disarm and disable this/parent probe */
1451 if (p == orig_p || aggr_kprobe_disabled(orig_p)) {
1452 disarm_kprobe(orig_p);
1453 orig_p->flags |= KPROBE_FLAG_DISABLED;
1454 }
1455 }
1457 return orig_p;
1458 }
1460 /*
1461 * Unregister a kprobe without a scheduler synchronization.
1462 */
1463 static int __kprobes __unregister_kprobe_top(struct kprobe *p)
1464 {
1465 struct kprobe *ap, *list_p;
1467 /* Disable kprobe. This will disarm it if needed. */
1468 ap = __disable_kprobe(p);
1469 if (ap == NULL)
1470 return -EINVAL;
1472 if (ap == p)
1473 /*
1474 * This probe is an independent(and non-optimized) kprobe
1475 * (not an aggrprobe). Remove from the hash list.
1476 */
1477 goto disarmed;
1479 /* Following process expects this probe is an aggrprobe */
1480 WARN_ON(!kprobe_aggrprobe(ap));
1482 if (list_is_singular(&ap->list) && kprobe_disarmed(ap))
1483 /*
1484 * !disarmed could be happen if the probe is under delayed
1485 * unoptimizing.
1486 */
1487 goto disarmed;
1488 else {
1489 /* If disabling probe has special handlers, update aggrprobe */
1490 if (p->break_handler && !kprobe_gone(p))
1491 ap->break_handler = NULL;
1492 if (p->post_handler && !kprobe_gone(p)) {
1493 list_for_each_entry_rcu(list_p, &ap->list, list) {
1494 if ((list_p != p) && (list_p->post_handler))
1495 goto noclean;
1496 }
1497 ap->post_handler = NULL;
1498 }
1499 noclean:
1500 /*
1501 * Remove from the aggrprobe: this path will do nothing in
1502 * __unregister_kprobe_bottom().
1503 */
1504 list_del_rcu(&p->list);
1505 if (!kprobe_disabled(ap) && !kprobes_all_disarmed)
1506 /*
1507 * Try to optimize this probe again, because post
1508 * handler may have been changed.
1509 */
1510 optimize_kprobe(ap);
1511 }
1512 return 0;
1514 disarmed:
1515 BUG_ON(!kprobe_disarmed(ap));
1516 hlist_del_rcu(&ap->hlist);
1517 return 0;
1518 }
1520 static void __kprobes __unregister_kprobe_bottom(struct kprobe *p)
1521 {
1522 struct kprobe *ap;
1524 if (list_empty(&p->list))
1525 /* This is an independent kprobe */
1526 arch_remove_kprobe(p);
1527 else if (list_is_singular(&p->list)) {
1528 /* This is the last child of an aggrprobe */
1529 ap = list_entry(p->list.next, struct kprobe, list);
1530 list_del(&p->list);
1531 free_aggr_kprobe(ap);
1532 }
1533 /* Otherwise, do nothing. */
1534 }
1536 int __kprobes register_kprobes(struct kprobe **kps, int num)
1537 {
1538 int i, ret = 0;
1540 if (num <= 0)
1541 return -EINVAL;
1542 for (i = 0; i < num; i++) {
1543 ret = register_kprobe(kps[i]);
1544 if (ret < 0) {
1545 if (i > 0)
1546 unregister_kprobes(kps, i);
1547 break;
1548 }
1549 }
1550 return ret;
1551 }
1552 EXPORT_SYMBOL_GPL(register_kprobes);
1554 void __kprobes unregister_kprobe(struct kprobe *p)
1555 {
1556 unregister_kprobes(&p, 1);
1557 }
1558 EXPORT_SYMBOL_GPL(unregister_kprobe);
1560 void __kprobes unregister_kprobes(struct kprobe **kps, int num)
1561 {
1562 int i;
1564 if (num <= 0)
1565 return;
1566 mutex_lock(&kprobe_mutex);
1567 for (i = 0; i < num; i++)
1568 if (__unregister_kprobe_top(kps[i]) < 0)
1569 kps[i]->addr = NULL;
1570 mutex_unlock(&kprobe_mutex);
1572 synchronize_sched();
1573 for (i = 0; i < num; i++)
1574 if (kps[i]->addr)
1575 __unregister_kprobe_bottom(kps[i]);
1576 }
1577 EXPORT_SYMBOL_GPL(unregister_kprobes);
1579 static struct notifier_block kprobe_exceptions_nb = {
1580 .notifier_call = kprobe_exceptions_notify,
1581 .priority = 0x7fffffff /* we need to be notified first */
1582 };
1584 unsigned long __weak arch_deref_entry_point(void *entry)
1585 {
1586 return (unsigned long)entry;
1587 }
1589 int __kprobes register_jprobes(struct jprobe **jps, int num)
1590 {
1591 struct jprobe *jp;
1592 int ret = 0, i;
1594 if (num <= 0)
1595 return -EINVAL;
1596 for (i = 0; i < num; i++) {
1597 unsigned long addr, offset;
1598 jp = jps[i];
1599 addr = arch_deref_entry_point(jp->entry);
1601 /* Verify probepoint is a function entry point */
1602 if (kallsyms_lookup_size_offset(addr, NULL, &offset) &&
1603 offset == 0) {
1604 jp->kp.pre_handler = setjmp_pre_handler;
1605 jp->kp.break_handler = longjmp_break_handler;
1606 ret = register_kprobe(&jp->kp);
1607 } else
1608 ret = -EINVAL;
1610 if (ret < 0) {
1611 if (i > 0)
1612 unregister_jprobes(jps, i);
1613 break;
1614 }
1615 }
1616 return ret;
1617 }
1618 EXPORT_SYMBOL_GPL(register_jprobes);
1620 int __kprobes register_jprobe(struct jprobe *jp)
1621 {
1622 return register_jprobes(&jp, 1);
1623 }
1624 EXPORT_SYMBOL_GPL(register_jprobe);
1626 void __kprobes unregister_jprobe(struct jprobe *jp)
1627 {
1628 unregister_jprobes(&jp, 1);
1629 }
1630 EXPORT_SYMBOL_GPL(unregister_jprobe);
1632 void __kprobes unregister_jprobes(struct jprobe **jps, int num)
1633 {
1634 int i;
1636 if (num <= 0)
1637 return;
1638 mutex_lock(&kprobe_mutex);
1639 for (i = 0; i < num; i++)
1640 if (__unregister_kprobe_top(&jps[i]->kp) < 0)
1641 jps[i]->kp.addr = NULL;
1642 mutex_unlock(&kprobe_mutex);
1644 synchronize_sched();
1645 for (i = 0; i < num; i++) {
1646 if (jps[i]->kp.addr)
1647 __unregister_kprobe_bottom(&jps[i]->kp);
1648 }
1649 }
1650 EXPORT_SYMBOL_GPL(unregister_jprobes);
1652 #ifdef CONFIG_KRETPROBES
1653 /*
1654 * This kprobe pre_handler is registered with every kretprobe. When probe
1655 * hits it will set up the return probe.
1656 */
1657 static int __kprobes pre_handler_kretprobe(struct kprobe *p,
1658 struct pt_regs *regs)
1659 {
1660 struct kretprobe *rp = container_of(p, struct kretprobe, kp);
1661 unsigned long hash, flags = 0;
1662 struct kretprobe_instance *ri;
1664 /*TODO: consider to only swap the RA after the last pre_handler fired */
1665 hash = hash_ptr(current, KPROBE_HASH_BITS);
1666 raw_spin_lock_irqsave(&rp->lock, flags);
1667 if (!hlist_empty(&rp->free_instances)) {
1668 ri = hlist_entry(rp->free_instances.first,
1669 struct kretprobe_instance, hlist);
1670 hlist_del(&ri->hlist);
1671 raw_spin_unlock_irqrestore(&rp->lock, flags);
1673 ri->rp = rp;
1674 ri->task = current;
1676 if (rp->entry_handler && rp->entry_handler(ri, regs))
1677 return 0;
1679 arch_prepare_kretprobe(ri, regs);
1681 /* XXX(hch): why is there no hlist_move_head? */
1682 INIT_HLIST_NODE(&ri->hlist);
1683 kretprobe_table_lock(hash, &flags);
1684 hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]);
1685 kretprobe_table_unlock(hash, &flags);
1686 } else {
1687 rp->nmissed++;
1688 raw_spin_unlock_irqrestore(&rp->lock, flags);
1689 }
1690 return 0;
1691 }
1693 int __kprobes register_kretprobe(struct kretprobe *rp)
1694 {
1695 int ret = 0;
1696 struct kretprobe_instance *inst;
1697 int i;
1698 void *addr;
1700 if (kretprobe_blacklist_size) {
1701 addr = kprobe_addr(&rp->kp);
1702 if (IS_ERR(addr))
1703 return PTR_ERR(addr);
1705 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
1706 if (kretprobe_blacklist[i].addr == addr)
1707 return -EINVAL;
1708 }
1709 }
1711 rp->kp.pre_handler = pre_handler_kretprobe;
1712 rp->kp.post_handler = NULL;
1713 rp->kp.fault_handler = NULL;
1714 rp->kp.break_handler = NULL;
1716 /* Pre-allocate memory for max kretprobe instances */
1717 if (rp->maxactive <= 0) {
1718 #ifdef CONFIG_PREEMPT
1719 rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());
1720 #else
1721 rp->maxactive = num_possible_cpus();
1722 #endif
1723 }
1724 raw_spin_lock_init(&rp->lock);
1725 INIT_HLIST_HEAD(&rp->free_instances);
1726 for (i = 0; i < rp->maxactive; i++) {
1727 inst = kmalloc(sizeof(struct kretprobe_instance) +
1728 rp->data_size, GFP_KERNEL);
1729 if (inst == NULL) {
1730 free_rp_inst(rp);
1731 return -ENOMEM;
1732 }
1733 INIT_HLIST_NODE(&inst->hlist);
1734 hlist_add_head(&inst->hlist, &rp->free_instances);
1735 }
1737 rp->nmissed = 0;
1738 /* Establish function entry probe point */
1739 ret = register_kprobe(&rp->kp);
1740 if (ret != 0)
1741 free_rp_inst(rp);
1742 return ret;
1743 }
1744 EXPORT_SYMBOL_GPL(register_kretprobe);
1746 int __kprobes register_kretprobes(struct kretprobe **rps, int num)
1747 {
1748 int ret = 0, i;
1750 if (num <= 0)
1751 return -EINVAL;
1752 for (i = 0; i < num; i++) {
1753 ret = register_kretprobe(rps[i]);
1754 if (ret < 0) {
1755 if (i > 0)
1756 unregister_kretprobes(rps, i);
1757 break;
1758 }
1759 }
1760 return ret;
1761 }
1762 EXPORT_SYMBOL_GPL(register_kretprobes);
1764 void __kprobes unregister_kretprobe(struct kretprobe *rp)
1765 {
1766 unregister_kretprobes(&rp, 1);
1767 }
1768 EXPORT_SYMBOL_GPL(unregister_kretprobe);
1770 void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
1771 {
1772 int i;
1774 if (num <= 0)
1775 return;
1776 mutex_lock(&kprobe_mutex);
1777 for (i = 0; i < num; i++)
1778 if (__unregister_kprobe_top(&rps[i]->kp) < 0)
1779 rps[i]->kp.addr = NULL;
1780 mutex_unlock(&kprobe_mutex);
1782 synchronize_sched();
1783 for (i = 0; i < num; i++) {
1784 if (rps[i]->kp.addr) {
1785 __unregister_kprobe_bottom(&rps[i]->kp);
1786 cleanup_rp_inst(rps[i]);
1787 }
1788 }
1789 }
1790 EXPORT_SYMBOL_GPL(unregister_kretprobes);
1792 #else /* CONFIG_KRETPROBES */
1793 int __kprobes register_kretprobe(struct kretprobe *rp)
1794 {
1795 return -ENOSYS;
1796 }
1797 EXPORT_SYMBOL_GPL(register_kretprobe);
1799 int __kprobes register_kretprobes(struct kretprobe **rps, int num)
1800 {
1801 return -ENOSYS;
1802 }
1803 EXPORT_SYMBOL_GPL(register_kretprobes);
1805 void __kprobes unregister_kretprobe(struct kretprobe *rp)
1806 {
1807 }
1808 EXPORT_SYMBOL_GPL(unregister_kretprobe);
1810 void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
1811 {
1812 }
1813 EXPORT_SYMBOL_GPL(unregister_kretprobes);
1815 static int __kprobes pre_handler_kretprobe(struct kprobe *p,
1816 struct pt_regs *regs)
1817 {
1818 return 0;
1819 }
1821 #endif /* CONFIG_KRETPROBES */
1823 /* Set the kprobe gone and remove its instruction buffer. */
1824 static void __kprobes kill_kprobe(struct kprobe *p)
1825 {
1826 struct kprobe *kp;
1828 p->flags |= KPROBE_FLAG_GONE;
1829 if (kprobe_aggrprobe(p)) {
1830 /*
1831 * If this is an aggr_kprobe, we have to list all the
1832 * chained probes and mark them GONE.
1833 */
1834 list_for_each_entry_rcu(kp, &p->list, list)
1835 kp->flags |= KPROBE_FLAG_GONE;
1836 p->post_handler = NULL;
1837 p->break_handler = NULL;
1838 kill_optimized_kprobe(p);
1839 }
1840 /*
1841 * Here, we can remove insn_slot safely, because no thread calls
1842 * the original probed function (which will be freed soon) any more.
1843 */
1844 arch_remove_kprobe(p);
1845 }
1847 /* Disable one kprobe */
1848 int __kprobes disable_kprobe(struct kprobe *kp)
1849 {
1850 int ret = 0;
1852 mutex_lock(&kprobe_mutex);
1854 /* Disable this kprobe */
1855 if (__disable_kprobe(kp) == NULL)
1856 ret = -EINVAL;
1858 mutex_unlock(&kprobe_mutex);
1859 return ret;
1860 }
1861 EXPORT_SYMBOL_GPL(disable_kprobe);
1863 /* Enable one kprobe */
1864 int __kprobes enable_kprobe(struct kprobe *kp)
1865 {
1866 int ret = 0;
1867 struct kprobe *p;
1869 mutex_lock(&kprobe_mutex);
1871 /* Check whether specified probe is valid. */
1872 p = __get_valid_kprobe(kp);
1873 if (unlikely(p == NULL)) {
1874 ret = -EINVAL;
1875 goto out;
1876 }
1878 if (kprobe_gone(kp)) {
1879 /* This kprobe has gone, we couldn't enable it. */
1880 ret = -EINVAL;
1881 goto out;
1882 }
1884 if (p != kp)
1885 kp->flags &= ~KPROBE_FLAG_DISABLED;
1887 if (!kprobes_all_disarmed && kprobe_disabled(p)) {
1888 p->flags &= ~KPROBE_FLAG_DISABLED;
1889 arm_kprobe(p);
1890 }
1891 out:
1892 mutex_unlock(&kprobe_mutex);
1893 return ret;
1894 }
1895 EXPORT_SYMBOL_GPL(enable_kprobe);
1897 void __kprobes dump_kprobe(struct kprobe *kp)
1898 {
1899 printk(KERN_WARNING "Dumping kprobe:\n");
1900 printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n",
1901 kp->symbol_name, kp->addr, kp->offset);
1902 }
1904 /* Module notifier call back, checking kprobes on the module */
1905 static int __kprobes kprobes_module_callback(struct notifier_block *nb,
1906 unsigned long val, void *data)
1907 {
1908 struct module *mod = data;
1909 struct hlist_head *head;
1910 struct hlist_node *node;
1911 struct kprobe *p;
1912 unsigned int i;
1913 int checkcore = (val == MODULE_STATE_GOING);
1915 if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
1916 return NOTIFY_DONE;
1918 /*
1919 * When MODULE_STATE_GOING was notified, both of module .text and
1920 * .init.text sections would be freed. When MODULE_STATE_LIVE was
1921 * notified, only .init.text section would be freed. We need to
1922 * disable kprobes which have been inserted in the sections.
1923 */
1924 mutex_lock(&kprobe_mutex);
1925 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1926 head = &kprobe_table[i];
1927 hlist_for_each_entry_rcu(p, node, head, hlist)
1928 if (within_module_init((unsigned long)p->addr, mod) ||
1929 (checkcore &&
1930 within_module_core((unsigned long)p->addr, mod))) {
1931 /*
1932 * The vaddr this probe is installed will soon
1933 * be vfreed buy not synced to disk. Hence,
1934 * disarming the breakpoint isn't needed.
1935 */
1936 kill_kprobe(p);
1937 }
1938 }
1939 mutex_unlock(&kprobe_mutex);
1940 return NOTIFY_DONE;
1941 }
1943 static struct notifier_block kprobe_module_nb = {
1944 .notifier_call = kprobes_module_callback,
1945 .priority = 0
1946 };
1948 static int __init init_kprobes(void)
1949 {
1950 int i, err = 0;
1951 unsigned long offset = 0, size = 0;
1952 char *modname, namebuf[128];
1953 const char *symbol_name;
1954 void *addr;
1955 struct kprobe_blackpoint *kb;
1957 /* FIXME allocate the probe table, currently defined statically */
1958 /* initialize all list heads */
1959 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1960 INIT_HLIST_HEAD(&kprobe_table[i]);
1961 INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
1962 raw_spin_lock_init(&(kretprobe_table_locks[i].lock));
1963 }
1965 /*
1966 * Lookup and populate the kprobe_blacklist.
1967 *
1968 * Unlike the kretprobe blacklist, we'll need to determine
1969 * the range of addresses that belong to the said functions,
1970 * since a kprobe need not necessarily be at the beginning
1971 * of a function.
1972 */
1973 for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
1974 kprobe_lookup_name(kb->name, addr);
1975 if (!addr)
1976 continue;
1978 kb->start_addr = (unsigned long)addr;
1979 symbol_name = kallsyms_lookup(kb->start_addr,
1980 &size, &offset, &modname, namebuf);
1981 if (!symbol_name)
1982 kb->range = 0;
1983 else
1984 kb->range = size;
1985 }
1987 if (kretprobe_blacklist_size) {
1988 /* lookup the function address from its name */
1989 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
1990 kprobe_lookup_name(kretprobe_blacklist[i].name,
1991 kretprobe_blacklist[i].addr);
1992 if (!kretprobe_blacklist[i].addr)
1993 printk("kretprobe: lookup failed: %s\n",
1994 kretprobe_blacklist[i].name);
1995 }
1996 }
1998 #if defined(CONFIG_OPTPROBES)
1999 #if defined(__ARCH_WANT_KPROBES_INSN_SLOT)
2000 /* Init kprobe_optinsn_slots */
2001 kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
2002 #endif
2003 /* By default, kprobes can be optimized */
2004 kprobes_allow_optimization = true;
2005 #endif
2007 /* By default, kprobes are armed */
2008 kprobes_all_disarmed = false;
2010 err = arch_init_kprobes();
2011 if (!err)
2012 err = register_die_notifier(&kprobe_exceptions_nb);
2013 if (!err)
2014 err = register_module_notifier(&kprobe_module_nb);
2016 kprobes_initialized = (err == 0);
2018 if (!err)
2019 init_test_probes();
2020 return err;
2021 }
2023 #ifdef CONFIG_DEBUG_FS
2024 static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p,
2025 const char *sym, int offset, char *modname, struct kprobe *pp)
2026 {
2027 char *kprobe_type;
2029 if (p->pre_handler == pre_handler_kretprobe)
2030 kprobe_type = "r";
2031 else if (p->pre_handler == setjmp_pre_handler)
2032 kprobe_type = "j";
2033 else
2034 kprobe_type = "k";
2036 if (sym)
2037 seq_printf(pi, "%p %s %s+0x%x %s ",
2038 p->addr, kprobe_type, sym, offset,
2039 (modname ? modname : " "));
2040 else
2041 seq_printf(pi, "%p %s %p ",
2042 p->addr, kprobe_type, p->addr);
2044 if (!pp)
2045 pp = p;
2046 seq_printf(pi, "%s%s%s\n",
2047 (kprobe_gone(p) ? "[GONE]" : ""),
2048 ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""),
2049 (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""));
2050 }
2052 static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos)
2053 {
2054 return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
2055 }
2057 static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
2058 {
2059 (*pos)++;
2060 if (*pos >= KPROBE_TABLE_SIZE)
2061 return NULL;
2062 return pos;
2063 }
2065 static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v)
2066 {
2067 /* Nothing to do */
2068 }
2070 static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v)
2071 {
2072 struct hlist_head *head;
2073 struct hlist_node *node;
2074 struct kprobe *p, *kp;
2075 const char *sym = NULL;
2076 unsigned int i = *(loff_t *) v;
2077 unsigned long offset = 0;
2078 char *modname, namebuf[128];
2080 head = &kprobe_table[i];
2081 preempt_disable();
2082 hlist_for_each_entry_rcu(p, node, head, hlist) {
2083 sym = kallsyms_lookup((unsigned long)p->addr, NULL,
2084 &offset, &modname, namebuf);
2085 if (kprobe_aggrprobe(p)) {
2086 list_for_each_entry_rcu(kp, &p->list, list)
2087 report_probe(pi, kp, sym, offset, modname, p);
2088 } else
2089 report_probe(pi, p, sym, offset, modname, NULL);
2090 }
2091 preempt_enable();
2092 return 0;
2093 }
2095 static const struct seq_operations kprobes_seq_ops = {
2096 .start = kprobe_seq_start,
2097 .next = kprobe_seq_next,
2098 .stop = kprobe_seq_stop,
2099 .show = show_kprobe_addr
2100 };
2102 static int __kprobes kprobes_open(struct inode *inode, struct file *filp)
2103 {
2104 return seq_open(filp, &kprobes_seq_ops);
2105 }
2107 static const struct file_operations debugfs_kprobes_operations = {
2108 .open = kprobes_open,
2109 .read = seq_read,
2110 .llseek = seq_lseek,
2111 .release = seq_release,
2112 };
2114 static void __kprobes arm_all_kprobes(void)
2115 {
2116 struct hlist_head *head;
2117 struct hlist_node *node;
2118 struct kprobe *p;
2119 unsigned int i;
2121 mutex_lock(&kprobe_mutex);
2123 /* If kprobes are armed, just return */
2124 if (!kprobes_all_disarmed)
2125 goto already_enabled;
2127 /* Arming kprobes doesn't optimize kprobe itself */
2128 mutex_lock(&text_mutex);
2129 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2130 head = &kprobe_table[i];
2131 hlist_for_each_entry_rcu(p, node, head, hlist)
2132 if (!kprobe_disabled(p))
2133 __arm_kprobe(p);
2134 }
2135 mutex_unlock(&text_mutex);
2137 kprobes_all_disarmed = false;
2138 printk(KERN_INFO "Kprobes globally enabled\n");
2140 already_enabled:
2141 mutex_unlock(&kprobe_mutex);
2142 return;
2143 }
2145 static void __kprobes disarm_all_kprobes(void)
2146 {
2147 struct hlist_head *head;
2148 struct hlist_node *node;
2149 struct kprobe *p;
2150 unsigned int i;
2152 mutex_lock(&kprobe_mutex);
2154 /* If kprobes are already disarmed, just return */
2155 if (kprobes_all_disarmed) {
2156 mutex_unlock(&kprobe_mutex);
2157 return;
2158 }
2160 kprobes_all_disarmed = true;
2161 printk(KERN_INFO "Kprobes globally disabled\n");
2163 mutex_lock(&text_mutex);
2164 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2165 head = &kprobe_table[i];
2166 hlist_for_each_entry_rcu(p, node, head, hlist) {
2167 if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p))
2168 __disarm_kprobe(p, false);
2169 }
2170 }
2171 mutex_unlock(&text_mutex);
2172 mutex_unlock(&kprobe_mutex);
2174 /* Wait for disarming all kprobes by optimizer */
2175 wait_for_kprobe_optimizer();
2176 }
2178 /*
2179 * XXX: The debugfs bool file interface doesn't allow for callbacks
2180 * when the bool state is switched. We can reuse that facility when
2181 * available
2182 */
2183 static ssize_t read_enabled_file_bool(struct file *file,
2184 char __user *user_buf, size_t count, loff_t *ppos)
2185 {
2186 char buf[3];
2188 if (!kprobes_all_disarmed)
2189 buf[0] = '1';
2190 else
2191 buf[0] = '0';
2192 buf[1] = '\n';
2193 buf[2] = 0x00;
2194 return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
2195 }
2197 static ssize_t write_enabled_file_bool(struct file *file,
2198 const char __user *user_buf, size_t count, loff_t *ppos)
2199 {
2200 char buf[32];
2201 int buf_size;
2203 buf_size = min(count, (sizeof(buf)-1));
2204 if (copy_from_user(buf, user_buf, buf_size))
2205 return -EFAULT;
2207 switch (buf[0]) {
2208 case 'y':
2209 case 'Y':
2210 case '1':
2211 arm_all_kprobes();
2212 break;
2213 case 'n':
2214 case 'N':
2215 case '0':
2216 disarm_all_kprobes();
2217 break;
2218 }
2220 return count;
2221 }
2223 static const struct file_operations fops_kp = {
2224 .read = read_enabled_file_bool,
2225 .write = write_enabled_file_bool,
2226 .llseek = default_llseek,
2227 };
2229 static int __kprobes debugfs_kprobe_init(void)
2230 {
2231 struct dentry *dir, *file;
2232 unsigned int value = 1;
2234 dir = debugfs_create_dir("kprobes", NULL);
2235 if (!dir)
2236 return -ENOMEM;
2238 file = debugfs_create_file("list", 0444, dir, NULL,
2239 &debugfs_kprobes_operations);
2240 if (!file) {
2241 debugfs_remove(dir);
2242 return -ENOMEM;
2243 }
2245 file = debugfs_create_file("enabled", 0600, dir,
2246 &value, &fops_kp);
2247 if (!file) {
2248 debugfs_remove(dir);
2249 return -ENOMEM;
2250 }
2252 return 0;
2253 }
2255 late_initcall(debugfs_kprobe_init);
2256 #endif /* CONFIG_DEBUG_FS */
2258 module_init(init_kprobes);
2260 /* defined in arch/.../kernel/kprobes.c */
2261 EXPORT_SYMBOL_GPL(jprobe_return);