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/kdebug.h>
47 #include <asm-generic/sections.h>
48 #include <asm/cacheflush.h>
49 #include <asm/errno.h>
50 #include <asm/uaccess.h>
52 #define KPROBE_HASH_BITS 6
53 #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
57 * Some oddball architectures like 64bit powerpc have function descriptors
58 * so this must be overridable.
60 #ifndef kprobe_lookup_name
61 #define kprobe_lookup_name(name, addr) \
62 addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name)))
65 static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
66 static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
68 /* NOTE: change this value only with kprobe_mutex held */
69 static bool kprobe_enabled;
71 DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */
72 DEFINE_SPINLOCK(kretprobe_lock); /* Protects kretprobe_inst_table */
73 static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
76 * Normally, functions that we'd want to prohibit kprobes in, are marked
77 * __kprobes. But, there are cases where such functions already belong to
78 * a different section (__sched for preempt_schedule)
80 * For such cases, we now have a blacklist
82 struct kprobe_blackpoint kprobe_blacklist[] = {
83 {"preempt_schedule",},
84 {NULL} /* Terminator */
87 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
89 * kprobe->ainsn.insn points to the copy of the instruction to be
90 * single-stepped. x86_64, POWER4 and above have no-exec support and
91 * stepping on the instruction on a vmalloced/kmalloced/data page
92 * is a recipe for disaster
94 #define INSNS_PER_PAGE (PAGE_SIZE/(MAX_INSN_SIZE * sizeof(kprobe_opcode_t)))
96 struct kprobe_insn_page {
97 struct hlist_node hlist;
98 kprobe_opcode_t *insns; /* Page of instruction slots */
99 char slot_used[INSNS_PER_PAGE];
104 enum kprobe_slot_state {
110 static struct hlist_head kprobe_insn_pages;
111 static int kprobe_garbage_slots;
112 static int collect_garbage_slots(void);
114 static int __kprobes check_safety(void)
117 #if defined(CONFIG_PREEMPT) && defined(CONFIG_PM)
118 ret = freeze_processes();
120 struct task_struct *p, *q;
121 do_each_thread(p, q) {
122 if (p != current && p->state == TASK_RUNNING &&
124 printk("Check failed: %s is running\n",p->comm);
128 } while_each_thread(p, q);
139 * get_insn_slot() - Find a slot on an executable page for an instruction.
140 * We allocate an executable page if there's no room on existing ones.
142 kprobe_opcode_t __kprobes *get_insn_slot(void)
144 struct kprobe_insn_page *kip;
145 struct hlist_node *pos;
148 hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) {
149 if (kip->nused < INSNS_PER_PAGE) {
151 for (i = 0; i < INSNS_PER_PAGE; i++) {
152 if (kip->slot_used[i] == SLOT_CLEAN) {
153 kip->slot_used[i] = SLOT_USED;
155 return kip->insns + (i * MAX_INSN_SIZE);
158 /* Surprise! No unused slots. Fix kip->nused. */
159 kip->nused = INSNS_PER_PAGE;
163 /* If there are any garbage slots, collect it and try again. */
164 if (kprobe_garbage_slots && collect_garbage_slots() == 0) {
167 /* All out of space. Need to allocate a new page. Use slot 0. */
168 kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL);
173 * Use module_alloc so this page is within +/- 2GB of where the
174 * kernel image and loaded module images reside. This is required
175 * so x86_64 can correctly handle the %rip-relative fixups.
177 kip->insns = module_alloc(PAGE_SIZE);
182 INIT_HLIST_NODE(&kip->hlist);
183 hlist_add_head(&kip->hlist, &kprobe_insn_pages);
184 memset(kip->slot_used, SLOT_CLEAN, INSNS_PER_PAGE);
185 kip->slot_used[0] = SLOT_USED;
191 /* Return 1 if all garbages are collected, otherwise 0. */
192 static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
194 kip->slot_used[idx] = SLOT_CLEAN;
196 if (kip->nused == 0) {
198 * Page is no longer in use. Free it unless
199 * it's the last one. We keep the last one
200 * so as not to have to set it up again the
201 * next time somebody inserts a probe.
203 hlist_del(&kip->hlist);
204 if (hlist_empty(&kprobe_insn_pages)) {
205 INIT_HLIST_NODE(&kip->hlist);
206 hlist_add_head(&kip->hlist,
209 module_free(NULL, kip->insns);
217 static int __kprobes collect_garbage_slots(void)
219 struct kprobe_insn_page *kip;
220 struct hlist_node *pos, *next;
222 /* Ensure no-one is preepmted on the garbages */
223 if (check_safety() != 0)
226 hlist_for_each_entry_safe(kip, pos, next, &kprobe_insn_pages, hlist) {
228 if (kip->ngarbage == 0)
230 kip->ngarbage = 0; /* we will collect all garbages */
231 for (i = 0; i < INSNS_PER_PAGE; i++) {
232 if (kip->slot_used[i] == SLOT_DIRTY &&
233 collect_one_slot(kip, i))
237 kprobe_garbage_slots = 0;
241 void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
243 struct kprobe_insn_page *kip;
244 struct hlist_node *pos;
246 hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) {
247 if (kip->insns <= slot &&
248 slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) {
249 int i = (slot - kip->insns) / MAX_INSN_SIZE;
251 kip->slot_used[i] = SLOT_DIRTY;
254 collect_one_slot(kip, i);
260 if (dirty && ++kprobe_garbage_slots > INSNS_PER_PAGE)
261 collect_garbage_slots();
265 /* We have preemption disabled.. so it is safe to use __ versions */
266 static inline void set_kprobe_instance(struct kprobe *kp)
268 __get_cpu_var(kprobe_instance) = kp;
271 static inline void reset_kprobe_instance(void)
273 __get_cpu_var(kprobe_instance) = NULL;
277 * This routine is called either:
278 * - under the kprobe_mutex - during kprobe_[un]register()
280 * - with preemption disabled - from arch/xxx/kernel/kprobes.c
282 struct kprobe __kprobes *get_kprobe(void *addr)
284 struct hlist_head *head;
285 struct hlist_node *node;
288 head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
289 hlist_for_each_entry_rcu(p, node, head, hlist) {
297 * Aggregate handlers for multiple kprobes support - these handlers
298 * take care of invoking the individual kprobe handlers on p->list
300 static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
304 list_for_each_entry_rcu(kp, &p->list, list) {
305 if (kp->pre_handler) {
306 set_kprobe_instance(kp);
307 if (kp->pre_handler(kp, regs))
310 reset_kprobe_instance();
315 static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
320 list_for_each_entry_rcu(kp, &p->list, list) {
321 if (kp->post_handler) {
322 set_kprobe_instance(kp);
323 kp->post_handler(kp, regs, flags);
324 reset_kprobe_instance();
329 static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
332 struct kprobe *cur = __get_cpu_var(kprobe_instance);
335 * if we faulted "during" the execution of a user specified
336 * probe handler, invoke just that probe's fault handler
338 if (cur && cur->fault_handler) {
339 if (cur->fault_handler(cur, regs, trapnr))
345 static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
347 struct kprobe *cur = __get_cpu_var(kprobe_instance);
350 if (cur && cur->break_handler) {
351 if (cur->break_handler(cur, regs))
354 reset_kprobe_instance();
358 /* Walks the list and increments nmissed count for multiprobe case */
359 void __kprobes kprobes_inc_nmissed_count(struct kprobe *p)
362 if (p->pre_handler != aggr_pre_handler) {
365 list_for_each_entry_rcu(kp, &p->list, list)
371 /* Called with kretprobe_lock held */
372 void __kprobes recycle_rp_inst(struct kretprobe_instance *ri,
373 struct hlist_head *head)
375 /* remove rp inst off the rprobe_inst_table */
376 hlist_del(&ri->hlist);
378 /* remove rp inst off the used list */
379 hlist_del(&ri->uflist);
380 /* put rp inst back onto the free list */
381 INIT_HLIST_NODE(&ri->uflist);
382 hlist_add_head(&ri->uflist, &ri->rp->free_instances);
385 hlist_add_head(&ri->hlist, head);
388 struct hlist_head __kprobes *kretprobe_inst_table_head(struct task_struct *tsk)
390 return &kretprobe_inst_table[hash_ptr(tsk, KPROBE_HASH_BITS)];
394 * This function is called from finish_task_switch when task tk becomes dead,
395 * so that we can recycle any function-return probe instances associated
396 * with this task. These left over instances represent probed functions
397 * that have been called but will never return.
399 void __kprobes kprobe_flush_task(struct task_struct *tk)
401 struct kretprobe_instance *ri;
402 struct hlist_head *head, empty_rp;
403 struct hlist_node *node, *tmp;
404 unsigned long flags = 0;
406 INIT_HLIST_HEAD(&empty_rp);
407 spin_lock_irqsave(&kretprobe_lock, flags);
408 head = kretprobe_inst_table_head(tk);
409 hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
411 recycle_rp_inst(ri, &empty_rp);
413 spin_unlock_irqrestore(&kretprobe_lock, flags);
415 hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
416 hlist_del(&ri->hlist);
421 static inline void free_rp_inst(struct kretprobe *rp)
423 struct kretprobe_instance *ri;
424 struct hlist_node *pos, *next;
426 hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, uflist) {
427 hlist_del(&ri->uflist);
433 * Keep all fields in the kprobe consistent
435 static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p)
437 memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t));
438 memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn));
442 * Add the new probe to old_p->list. Fail if this is the
443 * second jprobe at the address - two jprobes can't coexist
445 static int __kprobes add_new_kprobe(struct kprobe *old_p, struct kprobe *p)
447 if (p->break_handler) {
448 if (old_p->break_handler)
450 list_add_tail_rcu(&p->list, &old_p->list);
451 old_p->break_handler = aggr_break_handler;
453 list_add_rcu(&p->list, &old_p->list);
454 if (p->post_handler && !old_p->post_handler)
455 old_p->post_handler = aggr_post_handler;
460 * Fill in the required fields of the "manager kprobe". Replace the
461 * earlier kprobe in the hlist with the manager kprobe
463 static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
468 ap->pre_handler = aggr_pre_handler;
469 ap->fault_handler = aggr_fault_handler;
471 ap->post_handler = aggr_post_handler;
472 if (p->break_handler)
473 ap->break_handler = aggr_break_handler;
475 INIT_LIST_HEAD(&ap->list);
476 list_add_rcu(&p->list, &ap->list);
478 hlist_replace_rcu(&p->hlist, &ap->hlist);
482 * This is the second or subsequent kprobe at the address - handle
485 static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
491 if (old_p->pre_handler == aggr_pre_handler) {
492 copy_kprobe(old_p, p);
493 ret = add_new_kprobe(old_p, p);
495 ap = kzalloc(sizeof(struct kprobe), GFP_KERNEL);
498 add_aggr_kprobe(ap, old_p);
500 ret = add_new_kprobe(ap, p);
505 static int __kprobes in_kprobes_functions(unsigned long addr)
507 struct kprobe_blackpoint *kb;
509 if (addr >= (unsigned long)__kprobes_text_start &&
510 addr < (unsigned long)__kprobes_text_end)
513 * If there exists a kprobe_blacklist, verify and
514 * fail any probe registration in the prohibited area
516 for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
517 if (kb->start_addr) {
518 if (addr >= kb->start_addr &&
519 addr < (kb->start_addr + kb->range))
527 * If we have a symbol_name argument, look it up and add the offset field
528 * to it. This way, we can specify a relative address to a symbol.
530 static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p)
532 kprobe_opcode_t *addr = p->addr;
533 if (p->symbol_name) {
536 kprobe_lookup_name(p->symbol_name, addr);
541 return (kprobe_opcode_t *)(((char *)addr) + p->offset);
544 static int __kprobes __register_kprobe(struct kprobe *p,
545 unsigned long called_from)
548 struct kprobe *old_p;
549 struct module *probed_mod;
550 kprobe_opcode_t *addr;
552 addr = kprobe_addr(p);
557 if (!kernel_text_address((unsigned long) p->addr) ||
558 in_kprobes_functions((unsigned long) p->addr))
561 p->mod_refcounted = 0;
564 * Check if are we probing a module.
566 probed_mod = module_text_address((unsigned long) p->addr);
568 struct module *calling_mod = module_text_address(called_from);
570 * We must allow modules to probe themself and in this case
571 * avoid incrementing the module refcount, so as to allow
572 * unloading of self probing modules.
574 if (calling_mod && calling_mod != probed_mod) {
575 if (unlikely(!try_module_get(probed_mod)))
577 p->mod_refcounted = 1;
583 mutex_lock(&kprobe_mutex);
584 old_p = get_kprobe(p->addr);
586 ret = register_aggr_kprobe(old_p, p);
590 ret = arch_prepare_kprobe(p);
594 INIT_HLIST_NODE(&p->hlist);
595 hlist_add_head_rcu(&p->hlist,
596 &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
602 mutex_unlock(&kprobe_mutex);
604 if (ret && probed_mod)
605 module_put(probed_mod);
609 int __kprobes register_kprobe(struct kprobe *p)
611 return __register_kprobe(p, (unsigned long)__builtin_return_address(0));
614 void __kprobes unregister_kprobe(struct kprobe *p)
617 struct kprobe *old_p, *list_p;
620 mutex_lock(&kprobe_mutex);
621 old_p = get_kprobe(p->addr);
622 if (unlikely(!old_p)) {
623 mutex_unlock(&kprobe_mutex);
627 list_for_each_entry_rcu(list_p, &old_p->list, list)
629 /* kprobe p is a valid probe */
631 mutex_unlock(&kprobe_mutex);
636 (old_p->pre_handler == aggr_pre_handler &&
637 p->list.next == &old_p->list && p->list.prev == &old_p->list)) {
639 * Only probe on the hash list. Disarm only if kprobes are
640 * enabled - otherwise, the breakpoint would already have
641 * been removed. We save on flushing icache.
644 arch_disarm_kprobe(p);
645 hlist_del_rcu(&old_p->hlist);
648 list_del_rcu(&p->list);
652 mutex_unlock(&kprobe_mutex);
655 if (p->mod_refcounted) {
656 mod = module_text_address((unsigned long)p->addr);
663 list_del_rcu(&p->list);
666 arch_remove_kprobe(p);
668 mutex_lock(&kprobe_mutex);
669 if (p->break_handler)
670 old_p->break_handler = NULL;
671 if (p->post_handler){
672 list_for_each_entry_rcu(list_p, &old_p->list, list){
673 if (list_p->post_handler){
679 old_p->post_handler = NULL;
681 mutex_unlock(&kprobe_mutex);
685 static struct notifier_block kprobe_exceptions_nb = {
686 .notifier_call = kprobe_exceptions_notify,
687 .priority = 0x7fffffff /* we need to be notified first */
690 unsigned long __weak arch_deref_entry_point(void *entry)
692 return (unsigned long)entry;
695 int __kprobes register_jprobe(struct jprobe *jp)
697 unsigned long addr = arch_deref_entry_point(jp->entry);
699 if (!kernel_text_address(addr))
702 /* Todo: Verify probepoint is a function entry point */
703 jp->kp.pre_handler = setjmp_pre_handler;
704 jp->kp.break_handler = longjmp_break_handler;
706 return __register_kprobe(&jp->kp,
707 (unsigned long)__builtin_return_address(0));
710 void __kprobes unregister_jprobe(struct jprobe *jp)
712 unregister_kprobe(&jp->kp);
715 #ifdef CONFIG_KRETPROBES
717 * This kprobe pre_handler is registered with every kretprobe. When probe
718 * hits it will set up the return probe.
720 static int __kprobes pre_handler_kretprobe(struct kprobe *p,
721 struct pt_regs *regs)
723 struct kretprobe *rp = container_of(p, struct kretprobe, kp);
724 unsigned long flags = 0;
726 /*TODO: consider to only swap the RA after the last pre_handler fired */
727 spin_lock_irqsave(&kretprobe_lock, flags);
728 if (!hlist_empty(&rp->free_instances)) {
729 struct kretprobe_instance *ri;
731 ri = hlist_entry(rp->free_instances.first,
732 struct kretprobe_instance, uflist);
736 if (rp->entry_handler && rp->entry_handler(ri, regs)) {
737 spin_unlock_irqrestore(&kretprobe_lock, flags);
741 arch_prepare_kretprobe(ri, regs);
743 /* XXX(hch): why is there no hlist_move_head? */
744 hlist_del(&ri->uflist);
745 hlist_add_head(&ri->uflist, &ri->rp->used_instances);
746 hlist_add_head(&ri->hlist, kretprobe_inst_table_head(ri->task));
749 spin_unlock_irqrestore(&kretprobe_lock, flags);
753 int __kprobes register_kretprobe(struct kretprobe *rp)
756 struct kretprobe_instance *inst;
760 if (kretprobe_blacklist_size) {
761 addr = kprobe_addr(&rp->kp);
765 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
766 if (kretprobe_blacklist[i].addr == addr)
771 rp->kp.pre_handler = pre_handler_kretprobe;
772 rp->kp.post_handler = NULL;
773 rp->kp.fault_handler = NULL;
774 rp->kp.break_handler = NULL;
776 /* Pre-allocate memory for max kretprobe instances */
777 if (rp->maxactive <= 0) {
778 #ifdef CONFIG_PREEMPT
779 rp->maxactive = max(10, 2 * NR_CPUS);
781 rp->maxactive = NR_CPUS;
784 INIT_HLIST_HEAD(&rp->used_instances);
785 INIT_HLIST_HEAD(&rp->free_instances);
786 for (i = 0; i < rp->maxactive; i++) {
787 inst = kmalloc(sizeof(struct kretprobe_instance) +
788 rp->data_size, GFP_KERNEL);
793 INIT_HLIST_NODE(&inst->uflist);
794 hlist_add_head(&inst->uflist, &rp->free_instances);
798 /* Establish function entry probe point */
799 if ((ret = __register_kprobe(&rp->kp,
800 (unsigned long)__builtin_return_address(0))) != 0)
805 #else /* CONFIG_KRETPROBES */
806 int __kprobes register_kretprobe(struct kretprobe *rp)
811 static int __kprobes pre_handler_kretprobe(struct kprobe *p,
812 struct pt_regs *regs)
816 #endif /* CONFIG_KRETPROBES */
818 void __kprobes unregister_kretprobe(struct kretprobe *rp)
821 struct kretprobe_instance *ri;
822 struct hlist_node *pos, *next;
824 unregister_kprobe(&rp->kp);
827 spin_lock_irqsave(&kretprobe_lock, flags);
828 hlist_for_each_entry_safe(ri, pos, next, &rp->used_instances, uflist) {
830 hlist_del(&ri->uflist);
832 spin_unlock_irqrestore(&kretprobe_lock, flags);
836 static int __init init_kprobes(void)
839 unsigned long offset = 0, size = 0;
840 char *modname, namebuf[128];
841 const char *symbol_name;
843 struct kprobe_blackpoint *kb;
845 /* FIXME allocate the probe table, currently defined statically */
846 /* initialize all list heads */
847 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
848 INIT_HLIST_HEAD(&kprobe_table[i]);
849 INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
853 * Lookup and populate the kprobe_blacklist.
855 * Unlike the kretprobe blacklist, we'll need to determine
856 * the range of addresses that belong to the said functions,
857 * since a kprobe need not necessarily be at the beginning
860 for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
861 kprobe_lookup_name(kb->name, addr);
865 kb->start_addr = (unsigned long)addr;
866 symbol_name = kallsyms_lookup(kb->start_addr,
867 &size, &offset, &modname, namebuf);
874 if (kretprobe_blacklist_size) {
875 /* lookup the function address from its name */
876 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
877 kprobe_lookup_name(kretprobe_blacklist[i].name,
878 kretprobe_blacklist[i].addr);
879 if (!kretprobe_blacklist[i].addr)
880 printk("kretprobe: lookup failed: %s\n",
881 kretprobe_blacklist[i].name);
885 /* By default, kprobes are enabled */
886 kprobe_enabled = true;
888 err = arch_init_kprobes();
890 err = register_die_notifier(&kprobe_exceptions_nb);
897 #ifdef CONFIG_DEBUG_FS
898 static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p,
899 const char *sym, int offset,char *modname)
903 if (p->pre_handler == pre_handler_kretprobe)
905 else if (p->pre_handler == setjmp_pre_handler)
910 seq_printf(pi, "%p %s %s+0x%x %s\n", p->addr, kprobe_type,
911 sym, offset, (modname ? modname : " "));
913 seq_printf(pi, "%p %s %p\n", p->addr, kprobe_type, p->addr);
916 static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos)
918 return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
921 static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
924 if (*pos >= KPROBE_TABLE_SIZE)
929 static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v)
934 static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v)
936 struct hlist_head *head;
937 struct hlist_node *node;
938 struct kprobe *p, *kp;
939 const char *sym = NULL;
940 unsigned int i = *(loff_t *) v;
941 unsigned long offset = 0;
942 char *modname, namebuf[128];
944 head = &kprobe_table[i];
946 hlist_for_each_entry_rcu(p, node, head, hlist) {
947 sym = kallsyms_lookup((unsigned long)p->addr, NULL,
948 &offset, &modname, namebuf);
949 if (p->pre_handler == aggr_pre_handler) {
950 list_for_each_entry_rcu(kp, &p->list, list)
951 report_probe(pi, kp, sym, offset, modname);
953 report_probe(pi, p, sym, offset, modname);
959 static struct seq_operations kprobes_seq_ops = {
960 .start = kprobe_seq_start,
961 .next = kprobe_seq_next,
962 .stop = kprobe_seq_stop,
963 .show = show_kprobe_addr
966 static int __kprobes kprobes_open(struct inode *inode, struct file *filp)
968 return seq_open(filp, &kprobes_seq_ops);
971 static struct file_operations debugfs_kprobes_operations = {
972 .open = kprobes_open,
975 .release = seq_release,
978 static void __kprobes enable_all_kprobes(void)
980 struct hlist_head *head;
981 struct hlist_node *node;
985 mutex_lock(&kprobe_mutex);
987 /* If kprobes are already enabled, just return */
989 goto already_enabled;
991 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
992 head = &kprobe_table[i];
993 hlist_for_each_entry_rcu(p, node, head, hlist)
997 kprobe_enabled = true;
998 printk(KERN_INFO "Kprobes globally enabled\n");
1001 mutex_unlock(&kprobe_mutex);
1005 static void __kprobes disable_all_kprobes(void)
1007 struct hlist_head *head;
1008 struct hlist_node *node;
1012 mutex_lock(&kprobe_mutex);
1014 /* If kprobes are already disabled, just return */
1015 if (!kprobe_enabled)
1016 goto already_disabled;
1018 kprobe_enabled = false;
1019 printk(KERN_INFO "Kprobes globally disabled\n");
1020 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1021 head = &kprobe_table[i];
1022 hlist_for_each_entry_rcu(p, node, head, hlist) {
1023 if (!arch_trampoline_kprobe(p))
1024 arch_disarm_kprobe(p);
1028 mutex_unlock(&kprobe_mutex);
1029 /* Allow all currently running kprobes to complete */
1030 synchronize_sched();
1034 mutex_unlock(&kprobe_mutex);
1039 * XXX: The debugfs bool file interface doesn't allow for callbacks
1040 * when the bool state is switched. We can reuse that facility when
1043 static ssize_t read_enabled_file_bool(struct file *file,
1044 char __user *user_buf, size_t count, loff_t *ppos)
1054 return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
1057 static ssize_t write_enabled_file_bool(struct file *file,
1058 const char __user *user_buf, size_t count, loff_t *ppos)
1063 buf_size = min(count, (sizeof(buf)-1));
1064 if (copy_from_user(buf, user_buf, buf_size))
1071 enable_all_kprobes();
1076 disable_all_kprobes();
1083 static struct file_operations fops_kp = {
1084 .read = read_enabled_file_bool,
1085 .write = write_enabled_file_bool,
1088 static int __kprobes debugfs_kprobe_init(void)
1090 struct dentry *dir, *file;
1091 unsigned int value = 1;
1093 dir = debugfs_create_dir("kprobes", NULL);
1097 file = debugfs_create_file("list", 0444, dir, NULL,
1098 &debugfs_kprobes_operations);
1100 debugfs_remove(dir);
1104 file = debugfs_create_file("enabled", 0600, dir,
1107 debugfs_remove(dir);
1114 late_initcall(debugfs_kprobe_init);
1115 #endif /* CONFIG_DEBUG_FS */
1117 module_init(init_kprobes);
1119 EXPORT_SYMBOL_GPL(register_kprobe);
1120 EXPORT_SYMBOL_GPL(unregister_kprobe);
1121 EXPORT_SYMBOL_GPL(register_jprobe);
1122 EXPORT_SYMBOL_GPL(unregister_jprobe);
1123 #ifdef CONFIG_KPROBES
1124 EXPORT_SYMBOL_GPL(jprobe_return);
1127 #ifdef CONFIG_KPROBES
1128 EXPORT_SYMBOL_GPL(register_kretprobe);
1129 EXPORT_SYMBOL_GPL(unregister_kretprobe);