2 * Kernel Probes (KProbes)
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.
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.
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.
19 * Copyright (C) IBM Corporation, 2002, 2004
21 * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
22 * Probes initial implementation (includes suggestions from
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.
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/module.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)
62 * Some oddball architectures like 64bit powerpc have function descriptors
63 * so this must be overridable.
65 #ifndef kprobe_lookup_name
66 #define kprobe_lookup_name(name, addr) \
67 addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name)))
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;
81 spinlock_t lock ____cacheline_aligned_in_smp;
82 } kretprobe_table_locks[KPROBE_TABLE_SIZE];
84 static spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
86 return &(kretprobe_table_locks[hash].lock);
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)
94 * For such cases, we now have a blacklist
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 */
105 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
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
112 struct kprobe_insn_page {
113 struct list_head list;
114 kprobe_opcode_t *insns; /* Page of instruction slots */
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 */
130 static int slots_per_page(struct kprobe_insn_cache *c)
132 return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t));
135 enum kprobe_slot_state {
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,
147 static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c);
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.
153 static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c)
155 struct kprobe_insn_page *kip;
158 list_for_each_entry(kip, &c->pages, list) {
159 if (kip->nused < slots_per_page(c)) {
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;
165 return kip->insns + (i * c->insn_size);
168 /* kip->nused is broken. Fix it. */
169 kip->nused = slots_per_page(c);
174 /* If there are any garbage slots, collect it and try again. */
175 if (c->nr_garbage && collect_garbage_slots(c) == 0)
178 /* All out of space. Need to allocate a new page. */
179 kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL);
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.
188 kip->insns = module_alloc(PAGE_SIZE);
193 INIT_LIST_HEAD(&kip->list);
194 memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c));
195 kip->slot_used[0] = SLOT_USED;
198 list_add(&kip->list, &c->pages);
203 kprobe_opcode_t __kprobes *get_insn_slot(void)
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);
214 /* Return 1 if all garbages are collected, otherwise 0. */
215 static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
217 kip->slot_used[idx] = SLOT_CLEAN;
219 if (kip->nused == 0) {
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.
226 if (!list_is_singular(&kip->list)) {
227 list_del(&kip->list);
228 module_free(NULL, kip->insns);
236 static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c)
238 struct kprobe_insn_page *kip, *next;
240 /* Ensure no-one is interrupted on the garbages */
243 list_for_each_entry_safe(kip, next, &c->pages, list) {
245 if (kip->ngarbage == 0)
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))
258 static void __kprobes __free_insn_slot(struct kprobe_insn_cache *c,
259 kprobe_opcode_t *slot, int dirty)
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);
269 kip->slot_used[idx] = SLOT_DIRTY;
271 if (++c->nr_garbage > slots_per_page(c))
272 collect_garbage_slots(c);
274 collect_one_slot(kip, idx);
278 /* Could not free this slot. */
282 void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
284 mutex_lock(&kprobe_insn_mutex);
285 __free_insn_slot(&kprobe_insn_slots, slot, dirty);
286 mutex_unlock(&kprobe_insn_mutex);
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 */
296 /* Get a slot for optimized_kprobe buffer */
297 kprobe_opcode_t __kprobes *get_optinsn_slot(void)
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);
308 void __kprobes free_optinsn_slot(kprobe_opcode_t * slot, int dirty)
310 mutex_lock(&kprobe_optinsn_mutex);
311 __free_insn_slot(&kprobe_optinsn_slots, slot, dirty);
312 mutex_unlock(&kprobe_optinsn_mutex);
317 /* We have preemption disabled.. so it is safe to use __ versions */
318 static inline void set_kprobe_instance(struct kprobe *kp)
320 __get_cpu_var(kprobe_instance) = kp;
323 static inline void reset_kprobe_instance(void)
325 __get_cpu_var(kprobe_instance) = NULL;
329 * This routine is called either:
330 * - under the kprobe_mutex - during kprobe_[un]register()
332 * - with preemption disabled - from arch/xxx/kernel/kprobes.c
334 struct kprobe __kprobes *get_kprobe(void *addr)
336 struct hlist_head *head;
337 struct hlist_node *node;
340 head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
341 hlist_for_each_entry_rcu(p, node, head, hlist) {
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)
354 return p->pre_handler == aggr_pre_handler;
358 * Keep all fields in the kprobe consistent
360 static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p)
362 memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t));
363 memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn));
366 #ifdef CONFIG_OPTPROBES
367 /* NOTE: change this value only with kprobe_mutex held */
368 static bool kprobes_allow_optimization;
371 * Call all pre_handler on the list, but ignores its return value.
372 * This must be called from arch-dep optimized caller.
374 void __kprobes opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
378 list_for_each_entry_rcu(kp, &p->list, list) {
379 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
380 set_kprobe_instance(kp);
381 kp->pre_handler(kp, regs);
383 reset_kprobe_instance();
387 /* Return true(!0) if the kprobe is ready for optimization. */
388 static inline int kprobe_optready(struct kprobe *p)
390 struct optimized_kprobe *op;
392 if (kprobe_aggrprobe(p)) {
393 op = container_of(p, struct optimized_kprobe, kp);
394 return arch_prepared_optinsn(&op->optinsn);
401 * Return an optimized kprobe whose optimizing code replaces
402 * instructions including addr (exclude breakpoint).
404 static struct kprobe *__kprobes get_optimized_kprobe(unsigned long addr)
407 struct kprobe *p = NULL;
408 struct optimized_kprobe *op;
410 /* Don't check i == 0, since that is a breakpoint case. */
411 for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++)
412 p = get_kprobe((void *)(addr - i));
414 if (p && kprobe_optready(p)) {
415 op = container_of(p, struct optimized_kprobe, kp);
416 if (arch_within_optimized_kprobe(op, addr))
423 /* Optimization staging list, protected by kprobe_mutex */
424 static LIST_HEAD(optimizing_list);
426 static void kprobe_optimizer(struct work_struct *work);
427 static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
428 #define OPTIMIZE_DELAY 5
431 * Optimize (replace a breakpoint with a jump) kprobes listed on
434 static __kprobes void do_optimize_kprobes(void)
436 struct optimized_kprobe *op, *tmp;
439 * The optimization/unoptimization refers online_cpus via
440 * stop_machine() and cpu-hotplug modifies online_cpus.
441 * And same time, text_mutex will be held in cpu-hotplug and here.
442 * This combination can cause a deadlock (cpu-hotplug try to lock
443 * text_mutex but stop_machine can not be done because online_cpus
445 * To avoid this deadlock, we need to call get_online_cpus()
446 * for preventing cpu-hotplug outside of text_mutex locking.
449 mutex_lock(&text_mutex);
450 list_for_each_entry_safe(op, tmp, &optimizing_list, list) {
451 WARN_ON(kprobe_disabled(&op->kp));
452 if (arch_optimize_kprobe(op) < 0)
453 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
454 list_del_init(&op->list);
456 mutex_unlock(&text_mutex);
460 /* Kprobe jump optimizer */
461 static __kprobes void kprobe_optimizer(struct work_struct *work)
463 /* Lock modules while optimizing kprobes */
464 mutex_lock(&module_mutex);
465 mutex_lock(&kprobe_mutex);
466 if (kprobes_all_disarmed || !kprobes_allow_optimization)
470 * Wait for quiesence period to ensure all running interrupts
471 * are done. Because optprobe may modify multiple instructions
472 * there is a chance that Nth instruction is interrupted. In that
473 * case, running interrupt can return to 2nd-Nth byte of jump
474 * instruction. This wait is for avoiding it.
478 do_optimize_kprobes();
480 mutex_unlock(&kprobe_mutex);
481 mutex_unlock(&module_mutex);
484 /* Optimize kprobe if p is ready to be optimized */
485 static __kprobes void optimize_kprobe(struct kprobe *p)
487 struct optimized_kprobe *op;
489 /* Check if the kprobe is disabled or not ready for optimization. */
490 if (!kprobe_optready(p) || !kprobes_allow_optimization ||
491 (kprobe_disabled(p) || kprobes_all_disarmed))
494 /* Both of break_handler and post_handler are not supported. */
495 if (p->break_handler || p->post_handler)
498 op = container_of(p, struct optimized_kprobe, kp);
500 /* Check there is no other kprobes at the optimized instructions */
501 if (arch_check_optimized_kprobe(op) < 0)
504 /* Check if it is already optimized. */
505 if (op->kp.flags & KPROBE_FLAG_OPTIMIZED)
508 op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
509 list_add(&op->list, &optimizing_list);
510 if (!delayed_work_pending(&optimizing_work))
511 schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
514 /* Unoptimize a kprobe if p is optimized */
515 static __kprobes void unoptimize_kprobe(struct kprobe *p)
517 struct optimized_kprobe *op;
519 if ((p->flags & KPROBE_FLAG_OPTIMIZED) && kprobe_aggrprobe(p)) {
520 op = container_of(p, struct optimized_kprobe, kp);
521 if (!list_empty(&op->list))
522 /* Dequeue from the optimization queue */
523 list_del_init(&op->list);
525 /* Replace jump with break */
526 arch_unoptimize_kprobe(op);
527 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
531 /* Remove optimized instructions */
532 static void __kprobes kill_optimized_kprobe(struct kprobe *p)
534 struct optimized_kprobe *op;
536 op = container_of(p, struct optimized_kprobe, kp);
537 if (!list_empty(&op->list)) {
538 /* Dequeue from the optimization queue */
539 list_del_init(&op->list);
540 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
542 /* Don't unoptimize, because the target code will be freed. */
543 arch_remove_optimized_kprobe(op);
546 /* Try to prepare optimized instructions */
547 static __kprobes void prepare_optimized_kprobe(struct kprobe *p)
549 struct optimized_kprobe *op;
551 op = container_of(p, struct optimized_kprobe, kp);
552 arch_prepare_optimized_kprobe(op);
555 /* Free optimized instructions and optimized_kprobe */
556 static __kprobes void free_aggr_kprobe(struct kprobe *p)
558 struct optimized_kprobe *op;
560 op = container_of(p, struct optimized_kprobe, kp);
561 arch_remove_optimized_kprobe(op);
565 /* Allocate new optimized_kprobe and try to prepare optimized instructions */
566 static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
568 struct optimized_kprobe *op;
570 op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL);
574 INIT_LIST_HEAD(&op->list);
575 op->kp.addr = p->addr;
576 arch_prepare_optimized_kprobe(op);
581 static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p);
584 * Prepare an optimized_kprobe and optimize it
585 * NOTE: p must be a normal registered kprobe
587 static __kprobes void try_to_optimize_kprobe(struct kprobe *p)
590 struct optimized_kprobe *op;
592 ap = alloc_aggr_kprobe(p);
596 op = container_of(ap, struct optimized_kprobe, kp);
597 if (!arch_prepared_optinsn(&op->optinsn)) {
598 /* If failed to setup optimizing, fallback to kprobe */
599 free_aggr_kprobe(ap);
603 init_aggr_kprobe(ap, p);
608 /* This should be called with kprobe_mutex locked */
609 static void __kprobes optimize_all_kprobes(void)
611 struct hlist_head *head;
612 struct hlist_node *node;
616 /* If optimization is already allowed, just return */
617 if (kprobes_allow_optimization)
620 kprobes_allow_optimization = true;
621 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
622 head = &kprobe_table[i];
623 hlist_for_each_entry_rcu(p, node, head, hlist)
624 if (!kprobe_disabled(p))
627 printk(KERN_INFO "Kprobes globally optimized\n");
630 /* This should be called with kprobe_mutex locked */
631 static void __kprobes unoptimize_all_kprobes(void)
633 struct hlist_head *head;
634 struct hlist_node *node;
638 /* If optimization is already prohibited, just return */
639 if (!kprobes_allow_optimization)
642 kprobes_allow_optimization = false;
643 printk(KERN_INFO "Kprobes globally unoptimized\n");
644 get_online_cpus(); /* For avoiding text_mutex deadlock */
645 mutex_lock(&text_mutex);
646 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
647 head = &kprobe_table[i];
648 hlist_for_each_entry_rcu(p, node, head, hlist) {
649 if (!kprobe_disabled(p))
650 unoptimize_kprobe(p);
654 mutex_unlock(&text_mutex);
656 /* Allow all currently running kprobes to complete */
660 int sysctl_kprobes_optimization;
661 int proc_kprobes_optimization_handler(struct ctl_table *table, int write,
662 void __user *buffer, size_t *length,
667 mutex_lock(&kprobe_mutex);
668 sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0;
669 ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
671 if (sysctl_kprobes_optimization)
672 optimize_all_kprobes();
674 unoptimize_all_kprobes();
675 mutex_unlock(&kprobe_mutex);
679 #endif /* CONFIG_SYSCTL */
681 static void __kprobes __arm_kprobe(struct kprobe *p)
685 /* Check collision with other optimized kprobes */
686 _p = get_optimized_kprobe((unsigned long)p->addr);
688 unoptimize_kprobe(_p); /* Fallback to unoptimized kprobe */
691 optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */
694 static void __kprobes __disarm_kprobe(struct kprobe *p)
698 unoptimize_kprobe(p); /* Try to unoptimize */
699 arch_disarm_kprobe(p);
701 /* If another kprobe was blocked, optimize it. */
702 _p = get_optimized_kprobe((unsigned long)p->addr);
707 #else /* !CONFIG_OPTPROBES */
709 #define optimize_kprobe(p) do {} while (0)
710 #define unoptimize_kprobe(p) do {} while (0)
711 #define kill_optimized_kprobe(p) do {} while (0)
712 #define prepare_optimized_kprobe(p) do {} while (0)
713 #define try_to_optimize_kprobe(p) do {} while (0)
714 #define __arm_kprobe(p) arch_arm_kprobe(p)
715 #define __disarm_kprobe(p) arch_disarm_kprobe(p)
717 static __kprobes void free_aggr_kprobe(struct kprobe *p)
722 static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
724 return kzalloc(sizeof(struct kprobe), GFP_KERNEL);
726 #endif /* CONFIG_OPTPROBES */
728 /* Arm a kprobe with text_mutex */
729 static void __kprobes arm_kprobe(struct kprobe *kp)
732 * Here, since __arm_kprobe() doesn't use stop_machine(),
733 * this doesn't cause deadlock on text_mutex. So, we don't
734 * need get_online_cpus().
736 mutex_lock(&text_mutex);
738 mutex_unlock(&text_mutex);
741 /* Disarm a kprobe with text_mutex */
742 static void __kprobes disarm_kprobe(struct kprobe *kp)
744 get_online_cpus(); /* For avoiding text_mutex deadlock */
745 mutex_lock(&text_mutex);
747 mutex_unlock(&text_mutex);
752 * Aggregate handlers for multiple kprobes support - these handlers
753 * take care of invoking the individual kprobe handlers on p->list
755 static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
759 list_for_each_entry_rcu(kp, &p->list, list) {
760 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
761 set_kprobe_instance(kp);
762 if (kp->pre_handler(kp, regs))
765 reset_kprobe_instance();
770 static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
775 list_for_each_entry_rcu(kp, &p->list, list) {
776 if (kp->post_handler && likely(!kprobe_disabled(kp))) {
777 set_kprobe_instance(kp);
778 kp->post_handler(kp, regs, flags);
779 reset_kprobe_instance();
784 static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
787 struct kprobe *cur = __get_cpu_var(kprobe_instance);
790 * if we faulted "during" the execution of a user specified
791 * probe handler, invoke just that probe's fault handler
793 if (cur && cur->fault_handler) {
794 if (cur->fault_handler(cur, regs, trapnr))
800 static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
802 struct kprobe *cur = __get_cpu_var(kprobe_instance);
805 if (cur && cur->break_handler) {
806 if (cur->break_handler(cur, regs))
809 reset_kprobe_instance();
813 /* Walks the list and increments nmissed count for multiprobe case */
814 void __kprobes kprobes_inc_nmissed_count(struct kprobe *p)
817 if (!kprobe_aggrprobe(p)) {
820 list_for_each_entry_rcu(kp, &p->list, list)
826 void __kprobes recycle_rp_inst(struct kretprobe_instance *ri,
827 struct hlist_head *head)
829 struct kretprobe *rp = ri->rp;
831 /* remove rp inst off the rprobe_inst_table */
832 hlist_del(&ri->hlist);
833 INIT_HLIST_NODE(&ri->hlist);
835 spin_lock(&rp->lock);
836 hlist_add_head(&ri->hlist, &rp->free_instances);
837 spin_unlock(&rp->lock);
840 hlist_add_head(&ri->hlist, head);
843 void __kprobes kretprobe_hash_lock(struct task_struct *tsk,
844 struct hlist_head **head, unsigned long *flags)
845 __acquires(hlist_lock)
847 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
848 spinlock_t *hlist_lock;
850 *head = &kretprobe_inst_table[hash];
851 hlist_lock = kretprobe_table_lock_ptr(hash);
852 spin_lock_irqsave(hlist_lock, *flags);
855 static void __kprobes kretprobe_table_lock(unsigned long hash,
856 unsigned long *flags)
857 __acquires(hlist_lock)
859 spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
860 spin_lock_irqsave(hlist_lock, *flags);
863 void __kprobes kretprobe_hash_unlock(struct task_struct *tsk,
864 unsigned long *flags)
865 __releases(hlist_lock)
867 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
868 spinlock_t *hlist_lock;
870 hlist_lock = kretprobe_table_lock_ptr(hash);
871 spin_unlock_irqrestore(hlist_lock, *flags);
874 static void __kprobes kretprobe_table_unlock(unsigned long hash,
875 unsigned long *flags)
876 __releases(hlist_lock)
878 spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
879 spin_unlock_irqrestore(hlist_lock, *flags);
883 * This function is called from finish_task_switch when task tk becomes dead,
884 * so that we can recycle any function-return probe instances associated
885 * with this task. These left over instances represent probed functions
886 * that have been called but will never return.
888 void __kprobes kprobe_flush_task(struct task_struct *tk)
890 struct kretprobe_instance *ri;
891 struct hlist_head *head, empty_rp;
892 struct hlist_node *node, *tmp;
893 unsigned long hash, flags = 0;
895 if (unlikely(!kprobes_initialized))
896 /* Early boot. kretprobe_table_locks not yet initialized. */
899 hash = hash_ptr(tk, KPROBE_HASH_BITS);
900 head = &kretprobe_inst_table[hash];
901 kretprobe_table_lock(hash, &flags);
902 hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
904 recycle_rp_inst(ri, &empty_rp);
906 kretprobe_table_unlock(hash, &flags);
907 INIT_HLIST_HEAD(&empty_rp);
908 hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
909 hlist_del(&ri->hlist);
914 static inline void free_rp_inst(struct kretprobe *rp)
916 struct kretprobe_instance *ri;
917 struct hlist_node *pos, *next;
919 hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) {
920 hlist_del(&ri->hlist);
925 static void __kprobes cleanup_rp_inst(struct kretprobe *rp)
927 unsigned long flags, hash;
928 struct kretprobe_instance *ri;
929 struct hlist_node *pos, *next;
930 struct hlist_head *head;
933 for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) {
934 kretprobe_table_lock(hash, &flags);
935 head = &kretprobe_inst_table[hash];
936 hlist_for_each_entry_safe(ri, pos, next, head, hlist) {
940 kretprobe_table_unlock(hash, &flags);
946 * Add the new probe to ap->list. Fail if this is the
947 * second jprobe at the address - two jprobes can't coexist
949 static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p)
951 BUG_ON(kprobe_gone(ap) || kprobe_gone(p));
953 if (p->break_handler || p->post_handler)
954 unoptimize_kprobe(ap); /* Fall back to normal kprobe */
956 if (p->break_handler) {
957 if (ap->break_handler)
959 list_add_tail_rcu(&p->list, &ap->list);
960 ap->break_handler = aggr_break_handler;
962 list_add_rcu(&p->list, &ap->list);
963 if (p->post_handler && !ap->post_handler)
964 ap->post_handler = aggr_post_handler;
966 if (kprobe_disabled(ap) && !kprobe_disabled(p)) {
967 ap->flags &= ~KPROBE_FLAG_DISABLED;
968 if (!kprobes_all_disarmed)
969 /* Arm the breakpoint again. */
976 * Fill in the required fields of the "manager kprobe". Replace the
977 * earlier kprobe in the hlist with the manager kprobe
979 static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
981 /* Copy p's insn slot to ap */
985 ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED;
986 ap->pre_handler = aggr_pre_handler;
987 ap->fault_handler = aggr_fault_handler;
988 /* We don't care the kprobe which has gone. */
989 if (p->post_handler && !kprobe_gone(p))
990 ap->post_handler = aggr_post_handler;
991 if (p->break_handler && !kprobe_gone(p))
992 ap->break_handler = aggr_break_handler;
994 INIT_LIST_HEAD(&ap->list);
995 INIT_HLIST_NODE(&ap->hlist);
997 list_add_rcu(&p->list, &ap->list);
998 hlist_replace_rcu(&p->hlist, &ap->hlist);
1002 * This is the second or subsequent kprobe at the address - handle
1005 static int __kprobes register_aggr_kprobe(struct kprobe *orig_p,
1009 struct kprobe *ap = orig_p;
1011 if (!kprobe_aggrprobe(orig_p)) {
1012 /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */
1013 ap = alloc_aggr_kprobe(orig_p);
1016 init_aggr_kprobe(ap, orig_p);
1019 if (kprobe_gone(ap)) {
1021 * Attempting to insert new probe at the same location that
1022 * had a probe in the module vaddr area which already
1023 * freed. So, the instruction slot has already been
1024 * released. We need a new slot for the new probe.
1026 ret = arch_prepare_kprobe(ap);
1029 * Even if fail to allocate new slot, don't need to
1030 * free aggr_probe. It will be used next time, or
1031 * freed by unregister_kprobe.
1035 /* Prepare optimized instructions if possible. */
1036 prepare_optimized_kprobe(ap);
1039 * Clear gone flag to prevent allocating new slot again, and
1040 * set disabled flag because it is not armed yet.
1042 ap->flags = (ap->flags & ~KPROBE_FLAG_GONE)
1043 | KPROBE_FLAG_DISABLED;
1046 /* Copy ap's insn slot to p */
1048 return add_new_kprobe(ap, p);
1051 static int __kprobes in_kprobes_functions(unsigned long addr)
1053 struct kprobe_blackpoint *kb;
1055 if (addr >= (unsigned long)__kprobes_text_start &&
1056 addr < (unsigned long)__kprobes_text_end)
1059 * If there exists a kprobe_blacklist, verify and
1060 * fail any probe registration in the prohibited area
1062 for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
1063 if (kb->start_addr) {
1064 if (addr >= kb->start_addr &&
1065 addr < (kb->start_addr + kb->range))
1073 * If we have a symbol_name argument, look it up and add the offset field
1074 * to it. This way, we can specify a relative address to a symbol.
1076 static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p)
1078 kprobe_opcode_t *addr = p->addr;
1079 if (p->symbol_name) {
1082 kprobe_lookup_name(p->symbol_name, addr);
1087 return (kprobe_opcode_t *)(((char *)addr) + p->offset);
1090 /* Check passed kprobe is valid and return kprobe in kprobe_table. */
1091 static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p)
1093 struct kprobe *ap, *list_p;
1095 ap = get_kprobe(p->addr);
1100 list_for_each_entry_rcu(list_p, &ap->list, list)
1102 /* kprobe p is a valid probe */
1110 /* Return error if the kprobe is being re-registered */
1111 static inline int check_kprobe_rereg(struct kprobe *p)
1115 mutex_lock(&kprobe_mutex);
1116 if (__get_valid_kprobe(p))
1118 mutex_unlock(&kprobe_mutex);
1123 int __kprobes register_kprobe(struct kprobe *p)
1126 struct kprobe *old_p;
1127 struct module *probed_mod;
1128 kprobe_opcode_t *addr;
1130 addr = kprobe_addr(p);
1135 ret = check_kprobe_rereg(p);
1141 if (!kernel_text_address((unsigned long) p->addr) ||
1142 in_kprobes_functions((unsigned long) p->addr) ||
1143 ftrace_text_reserved(p->addr, p->addr) ||
1144 jump_label_text_reserved(p->addr, p->addr))
1145 goto fail_with_jump_label;
1147 /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
1148 p->flags &= KPROBE_FLAG_DISABLED;
1151 * Check if are we probing a module.
1153 probed_mod = __module_text_address((unsigned long) p->addr);
1156 * We must hold a refcount of the probed module while updating
1157 * its code to prohibit unexpected unloading.
1159 if (unlikely(!try_module_get(probed_mod)))
1160 goto fail_with_jump_label;
1163 * If the module freed .init.text, we couldn't insert
1166 if (within_module_init((unsigned long)p->addr, probed_mod) &&
1167 probed_mod->state != MODULE_STATE_COMING) {
1168 module_put(probed_mod);
1169 goto fail_with_jump_label;
1173 jump_label_unlock();
1176 INIT_LIST_HEAD(&p->list);
1177 mutex_lock(&kprobe_mutex);
1179 jump_label_lock(); /* needed to call jump_label_text_reserved() */
1181 get_online_cpus(); /* For avoiding text_mutex deadlock. */
1182 mutex_lock(&text_mutex);
1184 old_p = get_kprobe(p->addr);
1186 /* Since this may unoptimize old_p, locking text_mutex. */
1187 ret = register_aggr_kprobe(old_p, p);
1191 ret = arch_prepare_kprobe(p);
1195 INIT_HLIST_NODE(&p->hlist);
1196 hlist_add_head_rcu(&p->hlist,
1197 &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
1199 if (!kprobes_all_disarmed && !kprobe_disabled(p))
1202 /* Try to optimize kprobe */
1203 try_to_optimize_kprobe(p);
1206 mutex_unlock(&text_mutex);
1208 jump_label_unlock();
1209 mutex_unlock(&kprobe_mutex);
1212 module_put(probed_mod);
1216 fail_with_jump_label:
1218 jump_label_unlock();
1221 EXPORT_SYMBOL_GPL(register_kprobe);
1223 /* Check if all probes on the aggrprobe are disabled */
1224 static int __kprobes aggr_kprobe_disabled(struct kprobe *ap)
1228 list_for_each_entry_rcu(kp, &ap->list, list)
1229 if (!kprobe_disabled(kp))
1231 * There is an active probe on the list.
1232 * We can't disable this ap.
1239 /* Disable one kprobe: Make sure called under kprobe_mutex is locked */
1240 static struct kprobe *__kprobes __disable_kprobe(struct kprobe *p)
1242 struct kprobe *orig_p;
1244 /* Get an original kprobe for return */
1245 orig_p = __get_valid_kprobe(p);
1246 if (unlikely(orig_p == NULL))
1249 if (!kprobe_disabled(p)) {
1250 /* Disable probe if it is a child probe */
1252 p->flags |= KPROBE_FLAG_DISABLED;
1254 /* Try to disarm and disable this/parent probe */
1255 if (p == orig_p || aggr_kprobe_disabled(orig_p)) {
1256 disarm_kprobe(orig_p);
1257 orig_p->flags |= KPROBE_FLAG_DISABLED;
1265 * Unregister a kprobe without a scheduler synchronization.
1267 static int __kprobes __unregister_kprobe_top(struct kprobe *p)
1269 struct kprobe *ap, *list_p;
1271 /* Disable kprobe. This will disarm it if needed. */
1272 ap = __disable_kprobe(p);
1278 * This probe is an independent(and non-optimized) kprobe
1279 * (not an aggrprobe). Remove from the hash list.
1283 /* Following process expects this probe is an aggrprobe */
1284 WARN_ON(!kprobe_aggrprobe(ap));
1286 if (list_is_singular(&ap->list))
1287 /* This probe is the last child of aggrprobe */
1290 /* If disabling probe has special handlers, update aggrprobe */
1291 if (p->break_handler && !kprobe_gone(p))
1292 ap->break_handler = NULL;
1293 if (p->post_handler && !kprobe_gone(p)) {
1294 list_for_each_entry_rcu(list_p, &ap->list, list) {
1295 if ((list_p != p) && (list_p->post_handler))
1298 ap->post_handler = NULL;
1302 * Remove from the aggrprobe: this path will do nothing in
1303 * __unregister_kprobe_bottom().
1305 list_del_rcu(&p->list);
1306 if (!kprobe_disabled(ap) && !kprobes_all_disarmed)
1308 * Try to optimize this probe again, because post
1309 * handler may have been changed.
1311 optimize_kprobe(ap);
1316 hlist_del_rcu(&ap->hlist);
1320 static void __kprobes __unregister_kprobe_bottom(struct kprobe *p)
1324 if (list_empty(&p->list))
1325 arch_remove_kprobe(p);
1326 else if (list_is_singular(&p->list)) {
1327 /* "p" is the last child of an aggr_kprobe */
1328 ap = list_entry(p->list.next, struct kprobe, list);
1330 arch_remove_kprobe(ap);
1331 free_aggr_kprobe(ap);
1335 int __kprobes register_kprobes(struct kprobe **kps, int num)
1341 for (i = 0; i < num; i++) {
1342 ret = register_kprobe(kps[i]);
1345 unregister_kprobes(kps, i);
1351 EXPORT_SYMBOL_GPL(register_kprobes);
1353 void __kprobes unregister_kprobe(struct kprobe *p)
1355 unregister_kprobes(&p, 1);
1357 EXPORT_SYMBOL_GPL(unregister_kprobe);
1359 void __kprobes unregister_kprobes(struct kprobe **kps, int num)
1365 mutex_lock(&kprobe_mutex);
1366 for (i = 0; i < num; i++)
1367 if (__unregister_kprobe_top(kps[i]) < 0)
1368 kps[i]->addr = NULL;
1369 mutex_unlock(&kprobe_mutex);
1371 synchronize_sched();
1372 for (i = 0; i < num; i++)
1374 __unregister_kprobe_bottom(kps[i]);
1376 EXPORT_SYMBOL_GPL(unregister_kprobes);
1378 static struct notifier_block kprobe_exceptions_nb = {
1379 .notifier_call = kprobe_exceptions_notify,
1380 .priority = 0x7fffffff /* we need to be notified first */
1383 unsigned long __weak arch_deref_entry_point(void *entry)
1385 return (unsigned long)entry;
1388 int __kprobes register_jprobes(struct jprobe **jps, int num)
1395 for (i = 0; i < num; i++) {
1396 unsigned long addr, offset;
1398 addr = arch_deref_entry_point(jp->entry);
1400 /* Verify probepoint is a function entry point */
1401 if (kallsyms_lookup_size_offset(addr, NULL, &offset) &&
1403 jp->kp.pre_handler = setjmp_pre_handler;
1404 jp->kp.break_handler = longjmp_break_handler;
1405 ret = register_kprobe(&jp->kp);
1411 unregister_jprobes(jps, i);
1417 EXPORT_SYMBOL_GPL(register_jprobes);
1419 int __kprobes register_jprobe(struct jprobe *jp)
1421 return register_jprobes(&jp, 1);
1423 EXPORT_SYMBOL_GPL(register_jprobe);
1425 void __kprobes unregister_jprobe(struct jprobe *jp)
1427 unregister_jprobes(&jp, 1);
1429 EXPORT_SYMBOL_GPL(unregister_jprobe);
1431 void __kprobes unregister_jprobes(struct jprobe **jps, int num)
1437 mutex_lock(&kprobe_mutex);
1438 for (i = 0; i < num; i++)
1439 if (__unregister_kprobe_top(&jps[i]->kp) < 0)
1440 jps[i]->kp.addr = NULL;
1441 mutex_unlock(&kprobe_mutex);
1443 synchronize_sched();
1444 for (i = 0; i < num; i++) {
1445 if (jps[i]->kp.addr)
1446 __unregister_kprobe_bottom(&jps[i]->kp);
1449 EXPORT_SYMBOL_GPL(unregister_jprobes);
1451 #ifdef CONFIG_KRETPROBES
1453 * This kprobe pre_handler is registered with every kretprobe. When probe
1454 * hits it will set up the return probe.
1456 static int __kprobes pre_handler_kretprobe(struct kprobe *p,
1457 struct pt_regs *regs)
1459 struct kretprobe *rp = container_of(p, struct kretprobe, kp);
1460 unsigned long hash, flags = 0;
1461 struct kretprobe_instance *ri;
1463 /*TODO: consider to only swap the RA after the last pre_handler fired */
1464 hash = hash_ptr(current, KPROBE_HASH_BITS);
1465 spin_lock_irqsave(&rp->lock, flags);
1466 if (!hlist_empty(&rp->free_instances)) {
1467 ri = hlist_entry(rp->free_instances.first,
1468 struct kretprobe_instance, hlist);
1469 hlist_del(&ri->hlist);
1470 spin_unlock_irqrestore(&rp->lock, flags);
1475 if (rp->entry_handler && rp->entry_handler(ri, regs))
1478 arch_prepare_kretprobe(ri, regs);
1480 /* XXX(hch): why is there no hlist_move_head? */
1481 INIT_HLIST_NODE(&ri->hlist);
1482 kretprobe_table_lock(hash, &flags);
1483 hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]);
1484 kretprobe_table_unlock(hash, &flags);
1487 spin_unlock_irqrestore(&rp->lock, flags);
1492 int __kprobes register_kretprobe(struct kretprobe *rp)
1495 struct kretprobe_instance *inst;
1499 if (kretprobe_blacklist_size) {
1500 addr = kprobe_addr(&rp->kp);
1504 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
1505 if (kretprobe_blacklist[i].addr == addr)
1510 rp->kp.pre_handler = pre_handler_kretprobe;
1511 rp->kp.post_handler = NULL;
1512 rp->kp.fault_handler = NULL;
1513 rp->kp.break_handler = NULL;
1515 /* Pre-allocate memory for max kretprobe instances */
1516 if (rp->maxactive <= 0) {
1517 #ifdef CONFIG_PREEMPT
1518 rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());
1520 rp->maxactive = num_possible_cpus();
1523 spin_lock_init(&rp->lock);
1524 INIT_HLIST_HEAD(&rp->free_instances);
1525 for (i = 0; i < rp->maxactive; i++) {
1526 inst = kmalloc(sizeof(struct kretprobe_instance) +
1527 rp->data_size, GFP_KERNEL);
1532 INIT_HLIST_NODE(&inst->hlist);
1533 hlist_add_head(&inst->hlist, &rp->free_instances);
1537 /* Establish function entry probe point */
1538 ret = register_kprobe(&rp->kp);
1543 EXPORT_SYMBOL_GPL(register_kretprobe);
1545 int __kprobes register_kretprobes(struct kretprobe **rps, int num)
1551 for (i = 0; i < num; i++) {
1552 ret = register_kretprobe(rps[i]);
1555 unregister_kretprobes(rps, i);
1561 EXPORT_SYMBOL_GPL(register_kretprobes);
1563 void __kprobes unregister_kretprobe(struct kretprobe *rp)
1565 unregister_kretprobes(&rp, 1);
1567 EXPORT_SYMBOL_GPL(unregister_kretprobe);
1569 void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
1575 mutex_lock(&kprobe_mutex);
1576 for (i = 0; i < num; i++)
1577 if (__unregister_kprobe_top(&rps[i]->kp) < 0)
1578 rps[i]->kp.addr = NULL;
1579 mutex_unlock(&kprobe_mutex);
1581 synchronize_sched();
1582 for (i = 0; i < num; i++) {
1583 if (rps[i]->kp.addr) {
1584 __unregister_kprobe_bottom(&rps[i]->kp);
1585 cleanup_rp_inst(rps[i]);
1589 EXPORT_SYMBOL_GPL(unregister_kretprobes);
1591 #else /* CONFIG_KRETPROBES */
1592 int __kprobes register_kretprobe(struct kretprobe *rp)
1596 EXPORT_SYMBOL_GPL(register_kretprobe);
1598 int __kprobes register_kretprobes(struct kretprobe **rps, int num)
1602 EXPORT_SYMBOL_GPL(register_kretprobes);
1604 void __kprobes unregister_kretprobe(struct kretprobe *rp)
1607 EXPORT_SYMBOL_GPL(unregister_kretprobe);
1609 void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
1612 EXPORT_SYMBOL_GPL(unregister_kretprobes);
1614 static int __kprobes pre_handler_kretprobe(struct kprobe *p,
1615 struct pt_regs *regs)
1620 #endif /* CONFIG_KRETPROBES */
1622 /* Set the kprobe gone and remove its instruction buffer. */
1623 static void __kprobes kill_kprobe(struct kprobe *p)
1627 p->flags |= KPROBE_FLAG_GONE;
1628 if (kprobe_aggrprobe(p)) {
1630 * If this is an aggr_kprobe, we have to list all the
1631 * chained probes and mark them GONE.
1633 list_for_each_entry_rcu(kp, &p->list, list)
1634 kp->flags |= KPROBE_FLAG_GONE;
1635 p->post_handler = NULL;
1636 p->break_handler = NULL;
1637 kill_optimized_kprobe(p);
1640 * Here, we can remove insn_slot safely, because no thread calls
1641 * the original probed function (which will be freed soon) any more.
1643 arch_remove_kprobe(p);
1646 /* Disable one kprobe */
1647 int __kprobes disable_kprobe(struct kprobe *kp)
1651 mutex_lock(&kprobe_mutex);
1653 /* Disable this kprobe */
1654 if (__disable_kprobe(kp) == NULL)
1657 mutex_unlock(&kprobe_mutex);
1660 EXPORT_SYMBOL_GPL(disable_kprobe);
1662 /* Enable one kprobe */
1663 int __kprobes enable_kprobe(struct kprobe *kp)
1668 mutex_lock(&kprobe_mutex);
1670 /* Check whether specified probe is valid. */
1671 p = __get_valid_kprobe(kp);
1672 if (unlikely(p == NULL)) {
1677 if (kprobe_gone(kp)) {
1678 /* This kprobe has gone, we couldn't enable it. */
1684 kp->flags &= ~KPROBE_FLAG_DISABLED;
1686 if (!kprobes_all_disarmed && kprobe_disabled(p)) {
1687 p->flags &= ~KPROBE_FLAG_DISABLED;
1691 mutex_unlock(&kprobe_mutex);
1694 EXPORT_SYMBOL_GPL(enable_kprobe);
1696 void __kprobes dump_kprobe(struct kprobe *kp)
1698 printk(KERN_WARNING "Dumping kprobe:\n");
1699 printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n",
1700 kp->symbol_name, kp->addr, kp->offset);
1703 /* Module notifier call back, checking kprobes on the module */
1704 static int __kprobes kprobes_module_callback(struct notifier_block *nb,
1705 unsigned long val, void *data)
1707 struct module *mod = data;
1708 struct hlist_head *head;
1709 struct hlist_node *node;
1712 int checkcore = (val == MODULE_STATE_GOING);
1714 if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
1718 * When MODULE_STATE_GOING was notified, both of module .text and
1719 * .init.text sections would be freed. When MODULE_STATE_LIVE was
1720 * notified, only .init.text section would be freed. We need to
1721 * disable kprobes which have been inserted in the sections.
1723 mutex_lock(&kprobe_mutex);
1724 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1725 head = &kprobe_table[i];
1726 hlist_for_each_entry_rcu(p, node, head, hlist)
1727 if (within_module_init((unsigned long)p->addr, mod) ||
1729 within_module_core((unsigned long)p->addr, mod))) {
1731 * The vaddr this probe is installed will soon
1732 * be vfreed buy not synced to disk. Hence,
1733 * disarming the breakpoint isn't needed.
1738 mutex_unlock(&kprobe_mutex);
1742 static struct notifier_block kprobe_module_nb = {
1743 .notifier_call = kprobes_module_callback,
1747 static int __init init_kprobes(void)
1750 unsigned long offset = 0, size = 0;
1751 char *modname, namebuf[128];
1752 const char *symbol_name;
1754 struct kprobe_blackpoint *kb;
1756 /* FIXME allocate the probe table, currently defined statically */
1757 /* initialize all list heads */
1758 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1759 INIT_HLIST_HEAD(&kprobe_table[i]);
1760 INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
1761 spin_lock_init(&(kretprobe_table_locks[i].lock));
1765 * Lookup and populate the kprobe_blacklist.
1767 * Unlike the kretprobe blacklist, we'll need to determine
1768 * the range of addresses that belong to the said functions,
1769 * since a kprobe need not necessarily be at the beginning
1772 for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
1773 kprobe_lookup_name(kb->name, addr);
1777 kb->start_addr = (unsigned long)addr;
1778 symbol_name = kallsyms_lookup(kb->start_addr,
1779 &size, &offset, &modname, namebuf);
1786 if (kretprobe_blacklist_size) {
1787 /* lookup the function address from its name */
1788 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
1789 kprobe_lookup_name(kretprobe_blacklist[i].name,
1790 kretprobe_blacklist[i].addr);
1791 if (!kretprobe_blacklist[i].addr)
1792 printk("kretprobe: lookup failed: %s\n",
1793 kretprobe_blacklist[i].name);
1797 #if defined(CONFIG_OPTPROBES)
1798 #if defined(__ARCH_WANT_KPROBES_INSN_SLOT)
1799 /* Init kprobe_optinsn_slots */
1800 kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
1802 /* By default, kprobes can be optimized */
1803 kprobes_allow_optimization = true;
1806 /* By default, kprobes are armed */
1807 kprobes_all_disarmed = false;
1809 err = arch_init_kprobes();
1811 err = register_die_notifier(&kprobe_exceptions_nb);
1813 err = register_module_notifier(&kprobe_module_nb);
1815 kprobes_initialized = (err == 0);
1822 #ifdef CONFIG_DEBUG_FS
1823 static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p,
1824 const char *sym, int offset, char *modname, struct kprobe *pp)
1828 if (p->pre_handler == pre_handler_kretprobe)
1830 else if (p->pre_handler == setjmp_pre_handler)
1836 seq_printf(pi, "%p %s %s+0x%x %s ",
1837 p->addr, kprobe_type, sym, offset,
1838 (modname ? modname : " "));
1840 seq_printf(pi, "%p %s %p ",
1841 p->addr, kprobe_type, p->addr);
1845 seq_printf(pi, "%s%s%s\n",
1846 (kprobe_gone(p) ? "[GONE]" : ""),
1847 ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""),
1848 (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""));
1851 static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos)
1853 return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
1856 static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
1859 if (*pos >= KPROBE_TABLE_SIZE)
1864 static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v)
1869 static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v)
1871 struct hlist_head *head;
1872 struct hlist_node *node;
1873 struct kprobe *p, *kp;
1874 const char *sym = NULL;
1875 unsigned int i = *(loff_t *) v;
1876 unsigned long offset = 0;
1877 char *modname, namebuf[128];
1879 head = &kprobe_table[i];
1881 hlist_for_each_entry_rcu(p, node, head, hlist) {
1882 sym = kallsyms_lookup((unsigned long)p->addr, NULL,
1883 &offset, &modname, namebuf);
1884 if (kprobe_aggrprobe(p)) {
1885 list_for_each_entry_rcu(kp, &p->list, list)
1886 report_probe(pi, kp, sym, offset, modname, p);
1888 report_probe(pi, p, sym, offset, modname, NULL);
1894 static const struct seq_operations kprobes_seq_ops = {
1895 .start = kprobe_seq_start,
1896 .next = kprobe_seq_next,
1897 .stop = kprobe_seq_stop,
1898 .show = show_kprobe_addr
1901 static int __kprobes kprobes_open(struct inode *inode, struct file *filp)
1903 return seq_open(filp, &kprobes_seq_ops);
1906 static const struct file_operations debugfs_kprobes_operations = {
1907 .open = kprobes_open,
1909 .llseek = seq_lseek,
1910 .release = seq_release,
1913 static void __kprobes arm_all_kprobes(void)
1915 struct hlist_head *head;
1916 struct hlist_node *node;
1920 mutex_lock(&kprobe_mutex);
1922 /* If kprobes are armed, just return */
1923 if (!kprobes_all_disarmed)
1924 goto already_enabled;
1926 /* Arming kprobes doesn't optimize kprobe itself */
1927 mutex_lock(&text_mutex);
1928 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1929 head = &kprobe_table[i];
1930 hlist_for_each_entry_rcu(p, node, head, hlist)
1931 if (!kprobe_disabled(p))
1934 mutex_unlock(&text_mutex);
1936 kprobes_all_disarmed = false;
1937 printk(KERN_INFO "Kprobes globally enabled\n");
1940 mutex_unlock(&kprobe_mutex);
1944 static void __kprobes disarm_all_kprobes(void)
1946 struct hlist_head *head;
1947 struct hlist_node *node;
1951 mutex_lock(&kprobe_mutex);
1953 /* If kprobes are already disarmed, just return */
1954 if (kprobes_all_disarmed)
1955 goto already_disabled;
1957 kprobes_all_disarmed = true;
1958 printk(KERN_INFO "Kprobes globally disabled\n");
1961 * Here we call get_online_cpus() for avoiding text_mutex deadlock,
1962 * because disarming may also unoptimize kprobes.
1965 mutex_lock(&text_mutex);
1966 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1967 head = &kprobe_table[i];
1968 hlist_for_each_entry_rcu(p, node, head, hlist) {
1969 if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p))
1974 mutex_unlock(&text_mutex);
1976 mutex_unlock(&kprobe_mutex);
1977 /* Allow all currently running kprobes to complete */
1978 synchronize_sched();
1982 mutex_unlock(&kprobe_mutex);
1987 * XXX: The debugfs bool file interface doesn't allow for callbacks
1988 * when the bool state is switched. We can reuse that facility when
1991 static ssize_t read_enabled_file_bool(struct file *file,
1992 char __user *user_buf, size_t count, loff_t *ppos)
1996 if (!kprobes_all_disarmed)
2002 return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
2005 static ssize_t write_enabled_file_bool(struct file *file,
2006 const char __user *user_buf, size_t count, loff_t *ppos)
2011 buf_size = min(count, (sizeof(buf)-1));
2012 if (copy_from_user(buf, user_buf, buf_size))
2024 disarm_all_kprobes();
2031 static const struct file_operations fops_kp = {
2032 .read = read_enabled_file_bool,
2033 .write = write_enabled_file_bool,
2034 .llseek = default_llseek,
2037 static int __kprobes debugfs_kprobe_init(void)
2039 struct dentry *dir, *file;
2040 unsigned int value = 1;
2042 dir = debugfs_create_dir("kprobes", NULL);
2046 file = debugfs_create_file("list", 0444, dir, NULL,
2047 &debugfs_kprobes_operations);
2049 debugfs_remove(dir);
2053 file = debugfs_create_file("enabled", 0600, dir,
2056 debugfs_remove(dir);
2063 late_initcall(debugfs_kprobe_init);
2064 #endif /* CONFIG_DEBUG_FS */
2066 module_init(init_kprobes);
2068 /* defined in arch/.../kernel/kprobes.c */
2069 EXPORT_SYMBOL_GPL(jprobe_return);