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 INIT_LIST_HEAD(&p
->list
);
584 mutex_lock(&kprobe_mutex
);
585 old_p
= get_kprobe(p
->addr
);
587 ret
= register_aggr_kprobe(old_p
, p
);
591 ret
= arch_prepare_kprobe(p
);
595 INIT_HLIST_NODE(&p
->hlist
);
596 hlist_add_head_rcu(&p
->hlist
,
597 &kprobe_table
[hash_ptr(p
->addr
, KPROBE_HASH_BITS
)]);
603 mutex_unlock(&kprobe_mutex
);
605 if (ret
&& probed_mod
)
606 module_put(probed_mod
);
611 * Unregister a kprobe without a scheduler synchronization.
613 static int __kprobes
__unregister_kprobe_top(struct kprobe
*p
)
615 struct kprobe
*old_p
, *list_p
;
617 old_p
= get_kprobe(p
->addr
);
618 if (unlikely(!old_p
))
622 list_for_each_entry_rcu(list_p
, &old_p
->list
, list
)
624 /* kprobe p is a valid probe */
630 (old_p
->pre_handler
== aggr_pre_handler
&&
631 list_is_singular(&old_p
->list
))) {
633 * Only probe on the hash list. Disarm only if kprobes are
634 * enabled - otherwise, the breakpoint would already have
635 * been removed. We save on flushing icache.
638 arch_disarm_kprobe(p
);
639 hlist_del_rcu(&old_p
->hlist
);
641 if (p
->break_handler
)
642 old_p
->break_handler
= NULL
;
643 if (p
->post_handler
) {
644 list_for_each_entry_rcu(list_p
, &old_p
->list
, list
) {
645 if ((list_p
!= p
) && (list_p
->post_handler
))
648 old_p
->post_handler
= NULL
;
651 list_del_rcu(&p
->list
);
656 static void __kprobes
__unregister_kprobe_bottom(struct kprobe
*p
)
659 struct kprobe
*old_p
;
661 if (p
->mod_refcounted
) {
662 mod
= module_text_address((unsigned long)p
->addr
);
667 if (list_empty(&p
->list
) || list_is_singular(&p
->list
)) {
668 if (!list_empty(&p
->list
)) {
669 /* "p" is the last child of an aggr_kprobe */
670 old_p
= list_entry(p
->list
.next
, struct kprobe
, list
);
674 arch_remove_kprobe(p
);
678 static int __register_kprobes(struct kprobe
**kps
, int num
,
679 unsigned long called_from
)
685 for (i
= 0; i
< num
; i
++) {
686 ret
= __register_kprobe(kps
[i
], called_from
);
687 if (ret
< 0 && i
> 0) {
688 unregister_kprobes(kps
, i
);
696 * Registration and unregistration functions for kprobe.
698 int __kprobes
register_kprobe(struct kprobe
*p
)
700 return __register_kprobes(&p
, 1,
701 (unsigned long)__builtin_return_address(0));
704 void __kprobes
unregister_kprobe(struct kprobe
*p
)
706 unregister_kprobes(&p
, 1);
709 int __kprobes
register_kprobes(struct kprobe
**kps
, int num
)
711 return __register_kprobes(kps
, num
,
712 (unsigned long)__builtin_return_address(0));
715 void __kprobes
unregister_kprobes(struct kprobe
**kps
, int num
)
721 mutex_lock(&kprobe_mutex
);
722 for (i
= 0; i
< num
; i
++)
723 if (__unregister_kprobe_top(kps
[i
]) < 0)
725 mutex_unlock(&kprobe_mutex
);
728 for (i
= 0; i
< num
; i
++)
730 __unregister_kprobe_bottom(kps
[i
]);
733 static struct notifier_block kprobe_exceptions_nb
= {
734 .notifier_call
= kprobe_exceptions_notify
,
735 .priority
= 0x7fffffff /* we need to be notified first */
738 unsigned long __weak
arch_deref_entry_point(void *entry
)
740 return (unsigned long)entry
;
743 int __kprobes
register_jprobe(struct jprobe
*jp
)
745 unsigned long addr
= arch_deref_entry_point(jp
->entry
);
747 if (!kernel_text_address(addr
))
750 /* Todo: Verify probepoint is a function entry point */
751 jp
->kp
.pre_handler
= setjmp_pre_handler
;
752 jp
->kp
.break_handler
= longjmp_break_handler
;
754 return __register_kprobe(&jp
->kp
,
755 (unsigned long)__builtin_return_address(0));
758 void __kprobes
unregister_jprobe(struct jprobe
*jp
)
760 unregister_kprobe(&jp
->kp
);
763 #ifdef CONFIG_KRETPROBES
765 * This kprobe pre_handler is registered with every kretprobe. When probe
766 * hits it will set up the return probe.
768 static int __kprobes
pre_handler_kretprobe(struct kprobe
*p
,
769 struct pt_regs
*regs
)
771 struct kretprobe
*rp
= container_of(p
, struct kretprobe
, kp
);
772 unsigned long flags
= 0;
774 /*TODO: consider to only swap the RA after the last pre_handler fired */
775 spin_lock_irqsave(&kretprobe_lock
, flags
);
776 if (!hlist_empty(&rp
->free_instances
)) {
777 struct kretprobe_instance
*ri
;
779 ri
= hlist_entry(rp
->free_instances
.first
,
780 struct kretprobe_instance
, uflist
);
784 if (rp
->entry_handler
&& rp
->entry_handler(ri
, regs
)) {
785 spin_unlock_irqrestore(&kretprobe_lock
, flags
);
789 arch_prepare_kretprobe(ri
, regs
);
791 /* XXX(hch): why is there no hlist_move_head? */
792 hlist_del(&ri
->uflist
);
793 hlist_add_head(&ri
->uflist
, &ri
->rp
->used_instances
);
794 hlist_add_head(&ri
->hlist
, kretprobe_inst_table_head(ri
->task
));
797 spin_unlock_irqrestore(&kretprobe_lock
, flags
);
801 int __kprobes
register_kretprobe(struct kretprobe
*rp
)
804 struct kretprobe_instance
*inst
;
808 if (kretprobe_blacklist_size
) {
809 addr
= kprobe_addr(&rp
->kp
);
813 for (i
= 0; kretprobe_blacklist
[i
].name
!= NULL
; i
++) {
814 if (kretprobe_blacklist
[i
].addr
== addr
)
819 rp
->kp
.pre_handler
= pre_handler_kretprobe
;
820 rp
->kp
.post_handler
= NULL
;
821 rp
->kp
.fault_handler
= NULL
;
822 rp
->kp
.break_handler
= NULL
;
824 /* Pre-allocate memory for max kretprobe instances */
825 if (rp
->maxactive
<= 0) {
826 #ifdef CONFIG_PREEMPT
827 rp
->maxactive
= max(10, 2 * NR_CPUS
);
829 rp
->maxactive
= NR_CPUS
;
832 INIT_HLIST_HEAD(&rp
->used_instances
);
833 INIT_HLIST_HEAD(&rp
->free_instances
);
834 for (i
= 0; i
< rp
->maxactive
; i
++) {
835 inst
= kmalloc(sizeof(struct kretprobe_instance
) +
836 rp
->data_size
, GFP_KERNEL
);
841 INIT_HLIST_NODE(&inst
->uflist
);
842 hlist_add_head(&inst
->uflist
, &rp
->free_instances
);
846 /* Establish function entry probe point */
847 if ((ret
= __register_kprobe(&rp
->kp
,
848 (unsigned long)__builtin_return_address(0))) != 0)
853 #else /* CONFIG_KRETPROBES */
854 int __kprobes
register_kretprobe(struct kretprobe
*rp
)
859 static int __kprobes
pre_handler_kretprobe(struct kprobe
*p
,
860 struct pt_regs
*regs
)
864 #endif /* CONFIG_KRETPROBES */
866 void __kprobes
unregister_kretprobe(struct kretprobe
*rp
)
869 struct kretprobe_instance
*ri
;
870 struct hlist_node
*pos
, *next
;
872 unregister_kprobe(&rp
->kp
);
875 spin_lock_irqsave(&kretprobe_lock
, flags
);
876 hlist_for_each_entry_safe(ri
, pos
, next
, &rp
->used_instances
, uflist
) {
878 hlist_del(&ri
->uflist
);
880 spin_unlock_irqrestore(&kretprobe_lock
, flags
);
884 static int __init
init_kprobes(void)
887 unsigned long offset
= 0, size
= 0;
888 char *modname
, namebuf
[128];
889 const char *symbol_name
;
891 struct kprobe_blackpoint
*kb
;
893 /* FIXME allocate the probe table, currently defined statically */
894 /* initialize all list heads */
895 for (i
= 0; i
< KPROBE_TABLE_SIZE
; i
++) {
896 INIT_HLIST_HEAD(&kprobe_table
[i
]);
897 INIT_HLIST_HEAD(&kretprobe_inst_table
[i
]);
901 * Lookup and populate the kprobe_blacklist.
903 * Unlike the kretprobe blacklist, we'll need to determine
904 * the range of addresses that belong to the said functions,
905 * since a kprobe need not necessarily be at the beginning
908 for (kb
= kprobe_blacklist
; kb
->name
!= NULL
; kb
++) {
909 kprobe_lookup_name(kb
->name
, addr
);
913 kb
->start_addr
= (unsigned long)addr
;
914 symbol_name
= kallsyms_lookup(kb
->start_addr
,
915 &size
, &offset
, &modname
, namebuf
);
922 if (kretprobe_blacklist_size
) {
923 /* lookup the function address from its name */
924 for (i
= 0; kretprobe_blacklist
[i
].name
!= NULL
; i
++) {
925 kprobe_lookup_name(kretprobe_blacklist
[i
].name
,
926 kretprobe_blacklist
[i
].addr
);
927 if (!kretprobe_blacklist
[i
].addr
)
928 printk("kretprobe: lookup failed: %s\n",
929 kretprobe_blacklist
[i
].name
);
933 /* By default, kprobes are enabled */
934 kprobe_enabled
= true;
936 err
= arch_init_kprobes();
938 err
= register_die_notifier(&kprobe_exceptions_nb
);
945 #ifdef CONFIG_DEBUG_FS
946 static void __kprobes
report_probe(struct seq_file
*pi
, struct kprobe
*p
,
947 const char *sym
, int offset
,char *modname
)
951 if (p
->pre_handler
== pre_handler_kretprobe
)
953 else if (p
->pre_handler
== setjmp_pre_handler
)
958 seq_printf(pi
, "%p %s %s+0x%x %s\n", p
->addr
, kprobe_type
,
959 sym
, offset
, (modname
? modname
: " "));
961 seq_printf(pi
, "%p %s %p\n", p
->addr
, kprobe_type
, p
->addr
);
964 static void __kprobes
*kprobe_seq_start(struct seq_file
*f
, loff_t
*pos
)
966 return (*pos
< KPROBE_TABLE_SIZE
) ? pos
: NULL
;
969 static void __kprobes
*kprobe_seq_next(struct seq_file
*f
, void *v
, loff_t
*pos
)
972 if (*pos
>= KPROBE_TABLE_SIZE
)
977 static void __kprobes
kprobe_seq_stop(struct seq_file
*f
, void *v
)
982 static int __kprobes
show_kprobe_addr(struct seq_file
*pi
, void *v
)
984 struct hlist_head
*head
;
985 struct hlist_node
*node
;
986 struct kprobe
*p
, *kp
;
987 const char *sym
= NULL
;
988 unsigned int i
= *(loff_t
*) v
;
989 unsigned long offset
= 0;
990 char *modname
, namebuf
[128];
992 head
= &kprobe_table
[i
];
994 hlist_for_each_entry_rcu(p
, node
, head
, hlist
) {
995 sym
= kallsyms_lookup((unsigned long)p
->addr
, NULL
,
996 &offset
, &modname
, namebuf
);
997 if (p
->pre_handler
== aggr_pre_handler
) {
998 list_for_each_entry_rcu(kp
, &p
->list
, list
)
999 report_probe(pi
, kp
, sym
, offset
, modname
);
1001 report_probe(pi
, p
, sym
, offset
, modname
);
1007 static struct seq_operations kprobes_seq_ops
= {
1008 .start
= kprobe_seq_start
,
1009 .next
= kprobe_seq_next
,
1010 .stop
= kprobe_seq_stop
,
1011 .show
= show_kprobe_addr
1014 static int __kprobes
kprobes_open(struct inode
*inode
, struct file
*filp
)
1016 return seq_open(filp
, &kprobes_seq_ops
);
1019 static struct file_operations debugfs_kprobes_operations
= {
1020 .open
= kprobes_open
,
1022 .llseek
= seq_lseek
,
1023 .release
= seq_release
,
1026 static void __kprobes
enable_all_kprobes(void)
1028 struct hlist_head
*head
;
1029 struct hlist_node
*node
;
1033 mutex_lock(&kprobe_mutex
);
1035 /* If kprobes are already enabled, just return */
1037 goto already_enabled
;
1039 for (i
= 0; i
< KPROBE_TABLE_SIZE
; i
++) {
1040 head
= &kprobe_table
[i
];
1041 hlist_for_each_entry_rcu(p
, node
, head
, hlist
)
1045 kprobe_enabled
= true;
1046 printk(KERN_INFO
"Kprobes globally enabled\n");
1049 mutex_unlock(&kprobe_mutex
);
1053 static void __kprobes
disable_all_kprobes(void)
1055 struct hlist_head
*head
;
1056 struct hlist_node
*node
;
1060 mutex_lock(&kprobe_mutex
);
1062 /* If kprobes are already disabled, just return */
1063 if (!kprobe_enabled
)
1064 goto already_disabled
;
1066 kprobe_enabled
= false;
1067 printk(KERN_INFO
"Kprobes globally disabled\n");
1068 for (i
= 0; i
< KPROBE_TABLE_SIZE
; i
++) {
1069 head
= &kprobe_table
[i
];
1070 hlist_for_each_entry_rcu(p
, node
, head
, hlist
) {
1071 if (!arch_trampoline_kprobe(p
))
1072 arch_disarm_kprobe(p
);
1076 mutex_unlock(&kprobe_mutex
);
1077 /* Allow all currently running kprobes to complete */
1078 synchronize_sched();
1082 mutex_unlock(&kprobe_mutex
);
1087 * XXX: The debugfs bool file interface doesn't allow for callbacks
1088 * when the bool state is switched. We can reuse that facility when
1091 static ssize_t
read_enabled_file_bool(struct file
*file
,
1092 char __user
*user_buf
, size_t count
, loff_t
*ppos
)
1102 return simple_read_from_buffer(user_buf
, count
, ppos
, buf
, 2);
1105 static ssize_t
write_enabled_file_bool(struct file
*file
,
1106 const char __user
*user_buf
, size_t count
, loff_t
*ppos
)
1111 buf_size
= min(count
, (sizeof(buf
)-1));
1112 if (copy_from_user(buf
, user_buf
, buf_size
))
1119 enable_all_kprobes();
1124 disable_all_kprobes();
1131 static struct file_operations fops_kp
= {
1132 .read
= read_enabled_file_bool
,
1133 .write
= write_enabled_file_bool
,
1136 static int __kprobes
debugfs_kprobe_init(void)
1138 struct dentry
*dir
, *file
;
1139 unsigned int value
= 1;
1141 dir
= debugfs_create_dir("kprobes", NULL
);
1145 file
= debugfs_create_file("list", 0444, dir
, NULL
,
1146 &debugfs_kprobes_operations
);
1148 debugfs_remove(dir
);
1152 file
= debugfs_create_file("enabled", 0600, dir
,
1155 debugfs_remove(dir
);
1162 late_initcall(debugfs_kprobe_init
);
1163 #endif /* CONFIG_DEBUG_FS */
1165 module_init(init_kprobes
);
1167 EXPORT_SYMBOL_GPL(register_kprobe
);
1168 EXPORT_SYMBOL_GPL(unregister_kprobe
);
1169 EXPORT_SYMBOL_GPL(register_kprobes
);
1170 EXPORT_SYMBOL_GPL(unregister_kprobes
);
1171 EXPORT_SYMBOL_GPL(register_jprobe
);
1172 EXPORT_SYMBOL_GPL(unregister_jprobe
);
1173 #ifdef CONFIG_KPROBES
1174 EXPORT_SYMBOL_GPL(jprobe_return
);
1177 #ifdef CONFIG_KPROBES
1178 EXPORT_SYMBOL_GPL(register_kretprobe
);
1179 EXPORT_SYMBOL_GPL(unregister_kretprobe
);