gpiolib: Actually set output state in wm831x_gpio_direction_output()
[firewire-audio.git] / kernel / kprobes.c
blobfa034d29cf73d5730f531b7bfd98682278d077b4
1 /*
2 * Kernel Probes (KProbes)
3 * kernel/kprobes.c
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
23 * Rusty Russell).
24 * 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with
25 * hlists and exceptions notifier as suggested by Andi Kleen.
26 * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
27 * interface to access function arguments.
28 * 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes
29 * exceptions notifier to be first on the priority list.
30 * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston
31 * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
32 * <prasanna@in.ibm.com> added function-return probes.
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>
51 #include <asm-generic/sections.h>
52 #include <asm/cacheflush.h>
53 #include <asm/errno.h>
54 #include <asm/uaccess.h>
56 #define KPROBE_HASH_BITS 6
57 #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
61 * Some oddball architectures like 64bit powerpc have function descriptors
62 * so this must be overridable.
64 #ifndef kprobe_lookup_name
65 #define kprobe_lookup_name(name, addr) \
66 addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name)))
67 #endif
69 static int kprobes_initialized;
70 static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
71 static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
73 /* NOTE: change this value only with kprobe_mutex held */
74 static bool kprobes_all_disarmed;
76 static DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */
77 static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
78 static struct {
79 spinlock_t lock ____cacheline_aligned_in_smp;
80 } kretprobe_table_locks[KPROBE_TABLE_SIZE];
82 static spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
84 return &(kretprobe_table_locks[hash].lock);
88 * Normally, functions that we'd want to prohibit kprobes in, are marked
89 * __kprobes. But, there are cases where such functions already belong to
90 * a different section (__sched for preempt_schedule)
92 * For such cases, we now have a blacklist
94 static struct kprobe_blackpoint kprobe_blacklist[] = {
95 {"preempt_schedule",},
96 {"native_get_debugreg",},
97 {"irq_entries_start",},
98 {"common_interrupt",},
99 {"mcount",}, /* mcount can be called from everywhere */
100 {NULL} /* Terminator */
103 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
105 * kprobe->ainsn.insn points to the copy of the instruction to be
106 * single-stepped. x86_64, POWER4 and above have no-exec support and
107 * stepping on the instruction on a vmalloced/kmalloced/data page
108 * is a recipe for disaster
110 struct kprobe_insn_page {
111 struct list_head list;
112 kprobe_opcode_t *insns; /* Page of instruction slots */
113 int nused;
114 int ngarbage;
115 char slot_used[];
118 #define KPROBE_INSN_PAGE_SIZE(slots) \
119 (offsetof(struct kprobe_insn_page, slot_used) + \
120 (sizeof(char) * (slots)))
122 struct kprobe_insn_cache {
123 struct list_head pages; /* list of kprobe_insn_page */
124 size_t insn_size; /* size of instruction slot */
125 int nr_garbage;
128 static int slots_per_page(struct kprobe_insn_cache *c)
130 return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t));
133 enum kprobe_slot_state {
134 SLOT_CLEAN = 0,
135 SLOT_DIRTY = 1,
136 SLOT_USED = 2,
139 static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_slots */
140 static struct kprobe_insn_cache kprobe_insn_slots = {
141 .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages),
142 .insn_size = MAX_INSN_SIZE,
143 .nr_garbage = 0,
145 static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c);
148 * __get_insn_slot() - Find a slot on an executable page for an instruction.
149 * We allocate an executable page if there's no room on existing ones.
151 static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c)
153 struct kprobe_insn_page *kip;
155 retry:
156 list_for_each_entry(kip, &c->pages, list) {
157 if (kip->nused < slots_per_page(c)) {
158 int i;
159 for (i = 0; i < slots_per_page(c); i++) {
160 if (kip->slot_used[i] == SLOT_CLEAN) {
161 kip->slot_used[i] = SLOT_USED;
162 kip->nused++;
163 return kip->insns + (i * c->insn_size);
166 /* kip->nused is broken. Fix it. */
167 kip->nused = slots_per_page(c);
168 WARN_ON(1);
172 /* If there are any garbage slots, collect it and try again. */
173 if (c->nr_garbage && collect_garbage_slots(c) == 0)
174 goto retry;
176 /* All out of space. Need to allocate a new page. */
177 kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL);
178 if (!kip)
179 return NULL;
182 * Use module_alloc so this page is within +/- 2GB of where the
183 * kernel image and loaded module images reside. This is required
184 * so x86_64 can correctly handle the %rip-relative fixups.
186 kip->insns = module_alloc(PAGE_SIZE);
187 if (!kip->insns) {
188 kfree(kip);
189 return NULL;
191 INIT_LIST_HEAD(&kip->list);
192 memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c));
193 kip->slot_used[0] = SLOT_USED;
194 kip->nused = 1;
195 kip->ngarbage = 0;
196 list_add(&kip->list, &c->pages);
197 return kip->insns;
201 kprobe_opcode_t __kprobes *get_insn_slot(void)
203 kprobe_opcode_t *ret = NULL;
205 mutex_lock(&kprobe_insn_mutex);
206 ret = __get_insn_slot(&kprobe_insn_slots);
207 mutex_unlock(&kprobe_insn_mutex);
209 return ret;
212 /* Return 1 if all garbages are collected, otherwise 0. */
213 static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
215 kip->slot_used[idx] = SLOT_CLEAN;
216 kip->nused--;
217 if (kip->nused == 0) {
219 * Page is no longer in use. Free it unless
220 * it's the last one. We keep the last one
221 * so as not to have to set it up again the
222 * next time somebody inserts a probe.
224 if (!list_is_singular(&kip->list)) {
225 list_del(&kip->list);
226 module_free(NULL, kip->insns);
227 kfree(kip);
229 return 1;
231 return 0;
234 static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c)
236 struct kprobe_insn_page *kip, *next;
238 /* Ensure no-one is interrupted on the garbages */
239 synchronize_sched();
241 list_for_each_entry_safe(kip, next, &c->pages, list) {
242 int i;
243 if (kip->ngarbage == 0)
244 continue;
245 kip->ngarbage = 0; /* we will collect all garbages */
246 for (i = 0; i < slots_per_page(c); i++) {
247 if (kip->slot_used[i] == SLOT_DIRTY &&
248 collect_one_slot(kip, i))
249 break;
252 c->nr_garbage = 0;
253 return 0;
256 static void __kprobes __free_insn_slot(struct kprobe_insn_cache *c,
257 kprobe_opcode_t *slot, int dirty)
259 struct kprobe_insn_page *kip;
261 list_for_each_entry(kip, &c->pages, list) {
262 long idx = ((long)slot - (long)kip->insns) / c->insn_size;
263 if (idx >= 0 && idx < slots_per_page(c)) {
264 WARN_ON(kip->slot_used[idx] != SLOT_USED);
265 if (dirty) {
266 kip->slot_used[idx] = SLOT_DIRTY;
267 kip->ngarbage++;
268 if (++c->nr_garbage > slots_per_page(c))
269 collect_garbage_slots(c);
270 } else
271 collect_one_slot(kip, idx);
272 return;
275 /* Could not free this slot. */
276 WARN_ON(1);
279 void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
281 mutex_lock(&kprobe_insn_mutex);
282 __free_insn_slot(&kprobe_insn_slots, slot, dirty);
283 mutex_unlock(&kprobe_insn_mutex);
285 #ifdef CONFIG_OPTPROBES
286 /* For optimized_kprobe buffer */
287 static DEFINE_MUTEX(kprobe_optinsn_mutex); /* Protects kprobe_optinsn_slots */
288 static struct kprobe_insn_cache kprobe_optinsn_slots = {
289 .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
290 /* .insn_size is initialized later */
291 .nr_garbage = 0,
293 /* Get a slot for optimized_kprobe buffer */
294 kprobe_opcode_t __kprobes *get_optinsn_slot(void)
296 kprobe_opcode_t *ret = NULL;
298 mutex_lock(&kprobe_optinsn_mutex);
299 ret = __get_insn_slot(&kprobe_optinsn_slots);
300 mutex_unlock(&kprobe_optinsn_mutex);
302 return ret;
305 void __kprobes free_optinsn_slot(kprobe_opcode_t * slot, int dirty)
307 mutex_lock(&kprobe_optinsn_mutex);
308 __free_insn_slot(&kprobe_optinsn_slots, slot, dirty);
309 mutex_unlock(&kprobe_optinsn_mutex);
311 #endif
312 #endif
314 /* We have preemption disabled.. so it is safe to use __ versions */
315 static inline void set_kprobe_instance(struct kprobe *kp)
317 __get_cpu_var(kprobe_instance) = kp;
320 static inline void reset_kprobe_instance(void)
322 __get_cpu_var(kprobe_instance) = NULL;
326 * This routine is called either:
327 * - under the kprobe_mutex - during kprobe_[un]register()
328 * OR
329 * - with preemption disabled - from arch/xxx/kernel/kprobes.c
331 struct kprobe __kprobes *get_kprobe(void *addr)
333 struct hlist_head *head;
334 struct hlist_node *node;
335 struct kprobe *p;
337 head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
338 hlist_for_each_entry_rcu(p, node, head, hlist) {
339 if (p->addr == addr)
340 return p;
343 return NULL;
346 static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs);
348 /* Return true if the kprobe is an aggregator */
349 static inline int kprobe_aggrprobe(struct kprobe *p)
351 return p->pre_handler == aggr_pre_handler;
355 * Keep all fields in the kprobe consistent
357 static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p)
359 memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t));
360 memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn));
363 #ifdef CONFIG_OPTPROBES
364 /* NOTE: change this value only with kprobe_mutex held */
365 static bool kprobes_allow_optimization;
368 * Call all pre_handler on the list, but ignores its return value.
369 * This must be called from arch-dep optimized caller.
371 void __kprobes opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
373 struct kprobe *kp;
375 list_for_each_entry_rcu(kp, &p->list, list) {
376 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
377 set_kprobe_instance(kp);
378 kp->pre_handler(kp, regs);
380 reset_kprobe_instance();
384 /* Return true(!0) if the kprobe is ready for optimization. */
385 static inline int kprobe_optready(struct kprobe *p)
387 struct optimized_kprobe *op;
389 if (kprobe_aggrprobe(p)) {
390 op = container_of(p, struct optimized_kprobe, kp);
391 return arch_prepared_optinsn(&op->optinsn);
394 return 0;
398 * Return an optimized kprobe whose optimizing code replaces
399 * instructions including addr (exclude breakpoint).
401 struct kprobe *__kprobes get_optimized_kprobe(unsigned long addr)
403 int i;
404 struct kprobe *p = NULL;
405 struct optimized_kprobe *op;
407 /* Don't check i == 0, since that is a breakpoint case. */
408 for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++)
409 p = get_kprobe((void *)(addr - i));
411 if (p && kprobe_optready(p)) {
412 op = container_of(p, struct optimized_kprobe, kp);
413 if (arch_within_optimized_kprobe(op, addr))
414 return p;
417 return NULL;
420 /* Optimization staging list, protected by kprobe_mutex */
421 static LIST_HEAD(optimizing_list);
423 static void kprobe_optimizer(struct work_struct *work);
424 static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
425 #define OPTIMIZE_DELAY 5
427 /* Kprobe jump optimizer */
428 static __kprobes void kprobe_optimizer(struct work_struct *work)
430 struct optimized_kprobe *op, *tmp;
432 /* Lock modules while optimizing kprobes */
433 mutex_lock(&module_mutex);
434 mutex_lock(&kprobe_mutex);
435 if (kprobes_all_disarmed || !kprobes_allow_optimization)
436 goto end;
439 * Wait for quiesence period to ensure all running interrupts
440 * are done. Because optprobe may modify multiple instructions
441 * there is a chance that Nth instruction is interrupted. In that
442 * case, running interrupt can return to 2nd-Nth byte of jump
443 * instruction. This wait is for avoiding it.
445 synchronize_sched();
448 * The optimization/unoptimization refers online_cpus via
449 * stop_machine() and cpu-hotplug modifies online_cpus.
450 * And same time, text_mutex will be held in cpu-hotplug and here.
451 * This combination can cause a deadlock (cpu-hotplug try to lock
452 * text_mutex but stop_machine can not be done because online_cpus
453 * has been changed)
454 * To avoid this deadlock, we need to call get_online_cpus()
455 * for preventing cpu-hotplug outside of text_mutex locking.
457 get_online_cpus();
458 mutex_lock(&text_mutex);
459 list_for_each_entry_safe(op, tmp, &optimizing_list, list) {
460 WARN_ON(kprobe_disabled(&op->kp));
461 if (arch_optimize_kprobe(op) < 0)
462 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
463 list_del_init(&op->list);
465 mutex_unlock(&text_mutex);
466 put_online_cpus();
467 end:
468 mutex_unlock(&kprobe_mutex);
469 mutex_unlock(&module_mutex);
472 /* Optimize kprobe if p is ready to be optimized */
473 static __kprobes void optimize_kprobe(struct kprobe *p)
475 struct optimized_kprobe *op;
477 /* Check if the kprobe is disabled or not ready for optimization. */
478 if (!kprobe_optready(p) || !kprobes_allow_optimization ||
479 (kprobe_disabled(p) || kprobes_all_disarmed))
480 return;
482 /* Both of break_handler and post_handler are not supported. */
483 if (p->break_handler || p->post_handler)
484 return;
486 op = container_of(p, struct optimized_kprobe, kp);
488 /* Check there is no other kprobes at the optimized instructions */
489 if (arch_check_optimized_kprobe(op) < 0)
490 return;
492 /* Check if it is already optimized. */
493 if (op->kp.flags & KPROBE_FLAG_OPTIMIZED)
494 return;
496 op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
497 list_add(&op->list, &optimizing_list);
498 if (!delayed_work_pending(&optimizing_work))
499 schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
502 /* Unoptimize a kprobe if p is optimized */
503 static __kprobes void unoptimize_kprobe(struct kprobe *p)
505 struct optimized_kprobe *op;
507 if ((p->flags & KPROBE_FLAG_OPTIMIZED) && kprobe_aggrprobe(p)) {
508 op = container_of(p, struct optimized_kprobe, kp);
509 if (!list_empty(&op->list))
510 /* Dequeue from the optimization queue */
511 list_del_init(&op->list);
512 else
513 /* Replace jump with break */
514 arch_unoptimize_kprobe(op);
515 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
519 /* Remove optimized instructions */
520 static void __kprobes kill_optimized_kprobe(struct kprobe *p)
522 struct optimized_kprobe *op;
524 op = container_of(p, struct optimized_kprobe, kp);
525 if (!list_empty(&op->list)) {
526 /* Dequeue from the optimization queue */
527 list_del_init(&op->list);
528 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
530 /* Don't unoptimize, because the target code will be freed. */
531 arch_remove_optimized_kprobe(op);
534 /* Try to prepare optimized instructions */
535 static __kprobes void prepare_optimized_kprobe(struct kprobe *p)
537 struct optimized_kprobe *op;
539 op = container_of(p, struct optimized_kprobe, kp);
540 arch_prepare_optimized_kprobe(op);
543 /* Free optimized instructions and optimized_kprobe */
544 static __kprobes void free_aggr_kprobe(struct kprobe *p)
546 struct optimized_kprobe *op;
548 op = container_of(p, struct optimized_kprobe, kp);
549 arch_remove_optimized_kprobe(op);
550 kfree(op);
553 /* Allocate new optimized_kprobe and try to prepare optimized instructions */
554 static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
556 struct optimized_kprobe *op;
558 op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL);
559 if (!op)
560 return NULL;
562 INIT_LIST_HEAD(&op->list);
563 op->kp.addr = p->addr;
564 arch_prepare_optimized_kprobe(op);
566 return &op->kp;
569 static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p);
572 * Prepare an optimized_kprobe and optimize it
573 * NOTE: p must be a normal registered kprobe
575 static __kprobes void try_to_optimize_kprobe(struct kprobe *p)
577 struct kprobe *ap;
578 struct optimized_kprobe *op;
580 ap = alloc_aggr_kprobe(p);
581 if (!ap)
582 return;
584 op = container_of(ap, struct optimized_kprobe, kp);
585 if (!arch_prepared_optinsn(&op->optinsn)) {
586 /* If failed to setup optimizing, fallback to kprobe */
587 free_aggr_kprobe(ap);
588 return;
591 init_aggr_kprobe(ap, p);
592 optimize_kprobe(ap);
595 #ifdef CONFIG_SYSCTL
596 static void __kprobes optimize_all_kprobes(void)
598 struct hlist_head *head;
599 struct hlist_node *node;
600 struct kprobe *p;
601 unsigned int i;
603 /* If optimization is already allowed, just return */
604 if (kprobes_allow_optimization)
605 return;
607 kprobes_allow_optimization = true;
608 mutex_lock(&text_mutex);
609 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
610 head = &kprobe_table[i];
611 hlist_for_each_entry_rcu(p, node, head, hlist)
612 if (!kprobe_disabled(p))
613 optimize_kprobe(p);
615 mutex_unlock(&text_mutex);
616 printk(KERN_INFO "Kprobes globally optimized\n");
619 static void __kprobes unoptimize_all_kprobes(void)
621 struct hlist_head *head;
622 struct hlist_node *node;
623 struct kprobe *p;
624 unsigned int i;
626 /* If optimization is already prohibited, just return */
627 if (!kprobes_allow_optimization)
628 return;
630 kprobes_allow_optimization = false;
631 printk(KERN_INFO "Kprobes globally unoptimized\n");
632 get_online_cpus(); /* For avoiding text_mutex deadlock */
633 mutex_lock(&text_mutex);
634 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
635 head = &kprobe_table[i];
636 hlist_for_each_entry_rcu(p, node, head, hlist) {
637 if (!kprobe_disabled(p))
638 unoptimize_kprobe(p);
642 mutex_unlock(&text_mutex);
643 put_online_cpus();
644 /* Allow all currently running kprobes to complete */
645 synchronize_sched();
648 int sysctl_kprobes_optimization;
649 int proc_kprobes_optimization_handler(struct ctl_table *table, int write,
650 void __user *buffer, size_t *length,
651 loff_t *ppos)
653 int ret;
655 mutex_lock(&kprobe_mutex);
656 sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0;
657 ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
659 if (sysctl_kprobes_optimization)
660 optimize_all_kprobes();
661 else
662 unoptimize_all_kprobes();
663 mutex_unlock(&kprobe_mutex);
665 return ret;
667 #endif /* CONFIG_SYSCTL */
669 static void __kprobes __arm_kprobe(struct kprobe *p)
671 struct kprobe *old_p;
673 /* Check collision with other optimized kprobes */
674 old_p = get_optimized_kprobe((unsigned long)p->addr);
675 if (unlikely(old_p))
676 unoptimize_kprobe(old_p); /* Fallback to unoptimized kprobe */
678 arch_arm_kprobe(p);
679 optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */
682 static void __kprobes __disarm_kprobe(struct kprobe *p)
684 struct kprobe *old_p;
686 unoptimize_kprobe(p); /* Try to unoptimize */
687 arch_disarm_kprobe(p);
689 /* If another kprobe was blocked, optimize it. */
690 old_p = get_optimized_kprobe((unsigned long)p->addr);
691 if (unlikely(old_p))
692 optimize_kprobe(old_p);
695 #else /* !CONFIG_OPTPROBES */
697 #define optimize_kprobe(p) do {} while (0)
698 #define unoptimize_kprobe(p) do {} while (0)
699 #define kill_optimized_kprobe(p) do {} while (0)
700 #define prepare_optimized_kprobe(p) do {} while (0)
701 #define try_to_optimize_kprobe(p) do {} while (0)
702 #define __arm_kprobe(p) arch_arm_kprobe(p)
703 #define __disarm_kprobe(p) arch_disarm_kprobe(p)
705 static __kprobes void free_aggr_kprobe(struct kprobe *p)
707 kfree(p);
710 static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
712 return kzalloc(sizeof(struct kprobe), GFP_KERNEL);
714 #endif /* CONFIG_OPTPROBES */
716 /* Arm a kprobe with text_mutex */
717 static void __kprobes arm_kprobe(struct kprobe *kp)
720 * Here, since __arm_kprobe() doesn't use stop_machine(),
721 * this doesn't cause deadlock on text_mutex. So, we don't
722 * need get_online_cpus().
724 mutex_lock(&text_mutex);
725 __arm_kprobe(kp);
726 mutex_unlock(&text_mutex);
729 /* Disarm a kprobe with text_mutex */
730 static void __kprobes disarm_kprobe(struct kprobe *kp)
732 get_online_cpus(); /* For avoiding text_mutex deadlock */
733 mutex_lock(&text_mutex);
734 __disarm_kprobe(kp);
735 mutex_unlock(&text_mutex);
736 put_online_cpus();
740 * Aggregate handlers for multiple kprobes support - these handlers
741 * take care of invoking the individual kprobe handlers on p->list
743 static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
745 struct kprobe *kp;
747 list_for_each_entry_rcu(kp, &p->list, list) {
748 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
749 set_kprobe_instance(kp);
750 if (kp->pre_handler(kp, regs))
751 return 1;
753 reset_kprobe_instance();
755 return 0;
758 static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
759 unsigned long flags)
761 struct kprobe *kp;
763 list_for_each_entry_rcu(kp, &p->list, list) {
764 if (kp->post_handler && likely(!kprobe_disabled(kp))) {
765 set_kprobe_instance(kp);
766 kp->post_handler(kp, regs, flags);
767 reset_kprobe_instance();
772 static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
773 int trapnr)
775 struct kprobe *cur = __get_cpu_var(kprobe_instance);
778 * if we faulted "during" the execution of a user specified
779 * probe handler, invoke just that probe's fault handler
781 if (cur && cur->fault_handler) {
782 if (cur->fault_handler(cur, regs, trapnr))
783 return 1;
785 return 0;
788 static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
790 struct kprobe *cur = __get_cpu_var(kprobe_instance);
791 int ret = 0;
793 if (cur && cur->break_handler) {
794 if (cur->break_handler(cur, regs))
795 ret = 1;
797 reset_kprobe_instance();
798 return ret;
801 /* Walks the list and increments nmissed count for multiprobe case */
802 void __kprobes kprobes_inc_nmissed_count(struct kprobe *p)
804 struct kprobe *kp;
805 if (!kprobe_aggrprobe(p)) {
806 p->nmissed++;
807 } else {
808 list_for_each_entry_rcu(kp, &p->list, list)
809 kp->nmissed++;
811 return;
814 void __kprobes recycle_rp_inst(struct kretprobe_instance *ri,
815 struct hlist_head *head)
817 struct kretprobe *rp = ri->rp;
819 /* remove rp inst off the rprobe_inst_table */
820 hlist_del(&ri->hlist);
821 INIT_HLIST_NODE(&ri->hlist);
822 if (likely(rp)) {
823 spin_lock(&rp->lock);
824 hlist_add_head(&ri->hlist, &rp->free_instances);
825 spin_unlock(&rp->lock);
826 } else
827 /* Unregistering */
828 hlist_add_head(&ri->hlist, head);
831 void __kprobes kretprobe_hash_lock(struct task_struct *tsk,
832 struct hlist_head **head, unsigned long *flags)
834 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
835 spinlock_t *hlist_lock;
837 *head = &kretprobe_inst_table[hash];
838 hlist_lock = kretprobe_table_lock_ptr(hash);
839 spin_lock_irqsave(hlist_lock, *flags);
842 static void __kprobes kretprobe_table_lock(unsigned long hash,
843 unsigned long *flags)
845 spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
846 spin_lock_irqsave(hlist_lock, *flags);
849 void __kprobes kretprobe_hash_unlock(struct task_struct *tsk,
850 unsigned long *flags)
852 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
853 spinlock_t *hlist_lock;
855 hlist_lock = kretprobe_table_lock_ptr(hash);
856 spin_unlock_irqrestore(hlist_lock, *flags);
859 void __kprobes kretprobe_table_unlock(unsigned long hash, unsigned long *flags)
861 spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
862 spin_unlock_irqrestore(hlist_lock, *flags);
866 * This function is called from finish_task_switch when task tk becomes dead,
867 * so that we can recycle any function-return probe instances associated
868 * with this task. These left over instances represent probed functions
869 * that have been called but will never return.
871 void __kprobes kprobe_flush_task(struct task_struct *tk)
873 struct kretprobe_instance *ri;
874 struct hlist_head *head, empty_rp;
875 struct hlist_node *node, *tmp;
876 unsigned long hash, flags = 0;
878 if (unlikely(!kprobes_initialized))
879 /* Early boot. kretprobe_table_locks not yet initialized. */
880 return;
882 hash = hash_ptr(tk, KPROBE_HASH_BITS);
883 head = &kretprobe_inst_table[hash];
884 kretprobe_table_lock(hash, &flags);
885 hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
886 if (ri->task == tk)
887 recycle_rp_inst(ri, &empty_rp);
889 kretprobe_table_unlock(hash, &flags);
890 INIT_HLIST_HEAD(&empty_rp);
891 hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
892 hlist_del(&ri->hlist);
893 kfree(ri);
897 static inline void free_rp_inst(struct kretprobe *rp)
899 struct kretprobe_instance *ri;
900 struct hlist_node *pos, *next;
902 hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) {
903 hlist_del(&ri->hlist);
904 kfree(ri);
908 static void __kprobes cleanup_rp_inst(struct kretprobe *rp)
910 unsigned long flags, hash;
911 struct kretprobe_instance *ri;
912 struct hlist_node *pos, *next;
913 struct hlist_head *head;
915 /* No race here */
916 for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) {
917 kretprobe_table_lock(hash, &flags);
918 head = &kretprobe_inst_table[hash];
919 hlist_for_each_entry_safe(ri, pos, next, head, hlist) {
920 if (ri->rp == rp)
921 ri->rp = NULL;
923 kretprobe_table_unlock(hash, &flags);
925 free_rp_inst(rp);
929 * Add the new probe to ap->list. Fail if this is the
930 * second jprobe at the address - two jprobes can't coexist
932 static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p)
934 BUG_ON(kprobe_gone(ap) || kprobe_gone(p));
936 if (p->break_handler || p->post_handler)
937 unoptimize_kprobe(ap); /* Fall back to normal kprobe */
939 if (p->break_handler) {
940 if (ap->break_handler)
941 return -EEXIST;
942 list_add_tail_rcu(&p->list, &ap->list);
943 ap->break_handler = aggr_break_handler;
944 } else
945 list_add_rcu(&p->list, &ap->list);
946 if (p->post_handler && !ap->post_handler)
947 ap->post_handler = aggr_post_handler;
949 if (kprobe_disabled(ap) && !kprobe_disabled(p)) {
950 ap->flags &= ~KPROBE_FLAG_DISABLED;
951 if (!kprobes_all_disarmed)
952 /* Arm the breakpoint again. */
953 __arm_kprobe(ap);
955 return 0;
959 * Fill in the required fields of the "manager kprobe". Replace the
960 * earlier kprobe in the hlist with the manager kprobe
962 static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
964 /* Copy p's insn slot to ap */
965 copy_kprobe(p, ap);
966 flush_insn_slot(ap);
967 ap->addr = p->addr;
968 ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED;
969 ap->pre_handler = aggr_pre_handler;
970 ap->fault_handler = aggr_fault_handler;
971 /* We don't care the kprobe which has gone. */
972 if (p->post_handler && !kprobe_gone(p))
973 ap->post_handler = aggr_post_handler;
974 if (p->break_handler && !kprobe_gone(p))
975 ap->break_handler = aggr_break_handler;
977 INIT_LIST_HEAD(&ap->list);
978 INIT_HLIST_NODE(&ap->hlist);
980 list_add_rcu(&p->list, &ap->list);
981 hlist_replace_rcu(&p->hlist, &ap->hlist);
985 * This is the second or subsequent kprobe at the address - handle
986 * the intricacies
988 static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
989 struct kprobe *p)
991 int ret = 0;
992 struct kprobe *ap = old_p;
994 if (!kprobe_aggrprobe(old_p)) {
995 /* If old_p is not an aggr_kprobe, create new aggr_kprobe. */
996 ap = alloc_aggr_kprobe(old_p);
997 if (!ap)
998 return -ENOMEM;
999 init_aggr_kprobe(ap, old_p);
1002 if (kprobe_gone(ap)) {
1004 * Attempting to insert new probe at the same location that
1005 * had a probe in the module vaddr area which already
1006 * freed. So, the instruction slot has already been
1007 * released. We need a new slot for the new probe.
1009 ret = arch_prepare_kprobe(ap);
1010 if (ret)
1012 * Even if fail to allocate new slot, don't need to
1013 * free aggr_probe. It will be used next time, or
1014 * freed by unregister_kprobe.
1016 return ret;
1018 /* Prepare optimized instructions if possible. */
1019 prepare_optimized_kprobe(ap);
1022 * Clear gone flag to prevent allocating new slot again, and
1023 * set disabled flag because it is not armed yet.
1025 ap->flags = (ap->flags & ~KPROBE_FLAG_GONE)
1026 | KPROBE_FLAG_DISABLED;
1029 /* Copy ap's insn slot to p */
1030 copy_kprobe(ap, p);
1031 return add_new_kprobe(ap, p);
1034 /* Try to disable aggr_kprobe, and return 1 if succeeded.*/
1035 static int __kprobes try_to_disable_aggr_kprobe(struct kprobe *p)
1037 struct kprobe *kp;
1039 list_for_each_entry_rcu(kp, &p->list, list) {
1040 if (!kprobe_disabled(kp))
1042 * There is an active probe on the list.
1043 * We can't disable aggr_kprobe.
1045 return 0;
1047 p->flags |= KPROBE_FLAG_DISABLED;
1048 return 1;
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)
1057 return -EINVAL;
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))
1066 return -EINVAL;
1069 return 0;
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) {
1080 if (addr)
1081 return NULL;
1082 kprobe_lookup_name(p->symbol_name, addr);
1085 if (!addr)
1086 return NULL;
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 *old_p, *list_p;
1095 old_p = get_kprobe(p->addr);
1096 if (unlikely(!old_p))
1097 return NULL;
1099 if (p != old_p) {
1100 list_for_each_entry_rcu(list_p, &old_p->list, list)
1101 if (list_p == p)
1102 /* kprobe p is a valid probe */
1103 goto valid;
1104 return NULL;
1106 valid:
1107 return old_p;
1110 /* Return error if the kprobe is being re-registered */
1111 static inline int check_kprobe_rereg(struct kprobe *p)
1113 int ret = 0;
1114 struct kprobe *old_p;
1116 mutex_lock(&kprobe_mutex);
1117 old_p = __get_valid_kprobe(p);
1118 if (old_p)
1119 ret = -EINVAL;
1120 mutex_unlock(&kprobe_mutex);
1121 return ret;
1124 int __kprobes register_kprobe(struct kprobe *p)
1126 int ret = 0;
1127 struct kprobe *old_p;
1128 struct module *probed_mod;
1129 kprobe_opcode_t *addr;
1131 addr = kprobe_addr(p);
1132 if (!addr)
1133 return -EINVAL;
1134 p->addr = addr;
1136 ret = check_kprobe_rereg(p);
1137 if (ret)
1138 return ret;
1140 preempt_disable();
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 preempt_enable();
1145 return -EINVAL;
1148 /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
1149 p->flags &= KPROBE_FLAG_DISABLED;
1152 * Check if are we probing a module.
1154 probed_mod = __module_text_address((unsigned long) p->addr);
1155 if (probed_mod) {
1157 * We must hold a refcount of the probed module while updating
1158 * its code to prohibit unexpected unloading.
1160 if (unlikely(!try_module_get(probed_mod))) {
1161 preempt_enable();
1162 return -EINVAL;
1165 * If the module freed .init.text, we couldn't insert
1166 * kprobes in there.
1168 if (within_module_init((unsigned long)p->addr, probed_mod) &&
1169 probed_mod->state != MODULE_STATE_COMING) {
1170 module_put(probed_mod);
1171 preempt_enable();
1172 return -EINVAL;
1175 preempt_enable();
1177 p->nmissed = 0;
1178 INIT_LIST_HEAD(&p->list);
1179 mutex_lock(&kprobe_mutex);
1181 get_online_cpus(); /* For avoiding text_mutex deadlock. */
1182 mutex_lock(&text_mutex);
1184 old_p = get_kprobe(p->addr);
1185 if (old_p) {
1186 /* Since this may unoptimize old_p, locking text_mutex. */
1187 ret = register_aggr_kprobe(old_p, p);
1188 goto out;
1191 ret = arch_prepare_kprobe(p);
1192 if (ret)
1193 goto out;
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))
1200 __arm_kprobe(p);
1202 /* Try to optimize kprobe */
1203 try_to_optimize_kprobe(p);
1205 out:
1206 mutex_unlock(&text_mutex);
1207 put_online_cpus();
1208 mutex_unlock(&kprobe_mutex);
1210 if (probed_mod)
1211 module_put(probed_mod);
1213 return ret;
1215 EXPORT_SYMBOL_GPL(register_kprobe);
1218 * Unregister a kprobe without a scheduler synchronization.
1220 static int __kprobes __unregister_kprobe_top(struct kprobe *p)
1222 struct kprobe *old_p, *list_p;
1224 old_p = __get_valid_kprobe(p);
1225 if (old_p == NULL)
1226 return -EINVAL;
1228 if (old_p == p ||
1229 (kprobe_aggrprobe(old_p) &&
1230 list_is_singular(&old_p->list))) {
1232 * Only probe on the hash list. Disarm only if kprobes are
1233 * enabled and not gone - otherwise, the breakpoint would
1234 * already have been removed. We save on flushing icache.
1236 if (!kprobes_all_disarmed && !kprobe_disabled(old_p))
1237 disarm_kprobe(old_p);
1238 hlist_del_rcu(&old_p->hlist);
1239 } else {
1240 if (p->break_handler && !kprobe_gone(p))
1241 old_p->break_handler = NULL;
1242 if (p->post_handler && !kprobe_gone(p)) {
1243 list_for_each_entry_rcu(list_p, &old_p->list, list) {
1244 if ((list_p != p) && (list_p->post_handler))
1245 goto noclean;
1247 old_p->post_handler = NULL;
1249 noclean:
1250 list_del_rcu(&p->list);
1251 if (!kprobe_disabled(old_p)) {
1252 try_to_disable_aggr_kprobe(old_p);
1253 if (!kprobes_all_disarmed) {
1254 if (kprobe_disabled(old_p))
1255 disarm_kprobe(old_p);
1256 else
1257 /* Try to optimize this probe again */
1258 optimize_kprobe(old_p);
1262 return 0;
1265 static void __kprobes __unregister_kprobe_bottom(struct kprobe *p)
1267 struct kprobe *old_p;
1269 if (list_empty(&p->list))
1270 arch_remove_kprobe(p);
1271 else if (list_is_singular(&p->list)) {
1272 /* "p" is the last child of an aggr_kprobe */
1273 old_p = list_entry(p->list.next, struct kprobe, list);
1274 list_del(&p->list);
1275 arch_remove_kprobe(old_p);
1276 free_aggr_kprobe(old_p);
1280 int __kprobes register_kprobes(struct kprobe **kps, int num)
1282 int i, ret = 0;
1284 if (num <= 0)
1285 return -EINVAL;
1286 for (i = 0; i < num; i++) {
1287 ret = register_kprobe(kps[i]);
1288 if (ret < 0) {
1289 if (i > 0)
1290 unregister_kprobes(kps, i);
1291 break;
1294 return ret;
1296 EXPORT_SYMBOL_GPL(register_kprobes);
1298 void __kprobes unregister_kprobe(struct kprobe *p)
1300 unregister_kprobes(&p, 1);
1302 EXPORT_SYMBOL_GPL(unregister_kprobe);
1304 void __kprobes unregister_kprobes(struct kprobe **kps, int num)
1306 int i;
1308 if (num <= 0)
1309 return;
1310 mutex_lock(&kprobe_mutex);
1311 for (i = 0; i < num; i++)
1312 if (__unregister_kprobe_top(kps[i]) < 0)
1313 kps[i]->addr = NULL;
1314 mutex_unlock(&kprobe_mutex);
1316 synchronize_sched();
1317 for (i = 0; i < num; i++)
1318 if (kps[i]->addr)
1319 __unregister_kprobe_bottom(kps[i]);
1321 EXPORT_SYMBOL_GPL(unregister_kprobes);
1323 static struct notifier_block kprobe_exceptions_nb = {
1324 .notifier_call = kprobe_exceptions_notify,
1325 .priority = 0x7fffffff /* we need to be notified first */
1328 unsigned long __weak arch_deref_entry_point(void *entry)
1330 return (unsigned long)entry;
1333 int __kprobes register_jprobes(struct jprobe **jps, int num)
1335 struct jprobe *jp;
1336 int ret = 0, i;
1338 if (num <= 0)
1339 return -EINVAL;
1340 for (i = 0; i < num; i++) {
1341 unsigned long addr;
1342 jp = jps[i];
1343 addr = arch_deref_entry_point(jp->entry);
1345 if (!kernel_text_address(addr))
1346 ret = -EINVAL;
1347 else {
1348 /* Todo: Verify probepoint is a function entry point */
1349 jp->kp.pre_handler = setjmp_pre_handler;
1350 jp->kp.break_handler = longjmp_break_handler;
1351 ret = register_kprobe(&jp->kp);
1353 if (ret < 0) {
1354 if (i > 0)
1355 unregister_jprobes(jps, i);
1356 break;
1359 return ret;
1361 EXPORT_SYMBOL_GPL(register_jprobes);
1363 int __kprobes register_jprobe(struct jprobe *jp)
1365 return register_jprobes(&jp, 1);
1367 EXPORT_SYMBOL_GPL(register_jprobe);
1369 void __kprobes unregister_jprobe(struct jprobe *jp)
1371 unregister_jprobes(&jp, 1);
1373 EXPORT_SYMBOL_GPL(unregister_jprobe);
1375 void __kprobes unregister_jprobes(struct jprobe **jps, int num)
1377 int i;
1379 if (num <= 0)
1380 return;
1381 mutex_lock(&kprobe_mutex);
1382 for (i = 0; i < num; i++)
1383 if (__unregister_kprobe_top(&jps[i]->kp) < 0)
1384 jps[i]->kp.addr = NULL;
1385 mutex_unlock(&kprobe_mutex);
1387 synchronize_sched();
1388 for (i = 0; i < num; i++) {
1389 if (jps[i]->kp.addr)
1390 __unregister_kprobe_bottom(&jps[i]->kp);
1393 EXPORT_SYMBOL_GPL(unregister_jprobes);
1395 #ifdef CONFIG_KRETPROBES
1397 * This kprobe pre_handler is registered with every kretprobe. When probe
1398 * hits it will set up the return probe.
1400 static int __kprobes pre_handler_kretprobe(struct kprobe *p,
1401 struct pt_regs *regs)
1403 struct kretprobe *rp = container_of(p, struct kretprobe, kp);
1404 unsigned long hash, flags = 0;
1405 struct kretprobe_instance *ri;
1407 /*TODO: consider to only swap the RA after the last pre_handler fired */
1408 hash = hash_ptr(current, KPROBE_HASH_BITS);
1409 spin_lock_irqsave(&rp->lock, flags);
1410 if (!hlist_empty(&rp->free_instances)) {
1411 ri = hlist_entry(rp->free_instances.first,
1412 struct kretprobe_instance, hlist);
1413 hlist_del(&ri->hlist);
1414 spin_unlock_irqrestore(&rp->lock, flags);
1416 ri->rp = rp;
1417 ri->task = current;
1419 if (rp->entry_handler && rp->entry_handler(ri, regs))
1420 return 0;
1422 arch_prepare_kretprobe(ri, regs);
1424 /* XXX(hch): why is there no hlist_move_head? */
1425 INIT_HLIST_NODE(&ri->hlist);
1426 kretprobe_table_lock(hash, &flags);
1427 hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]);
1428 kretprobe_table_unlock(hash, &flags);
1429 } else {
1430 rp->nmissed++;
1431 spin_unlock_irqrestore(&rp->lock, flags);
1433 return 0;
1436 int __kprobes register_kretprobe(struct kretprobe *rp)
1438 int ret = 0;
1439 struct kretprobe_instance *inst;
1440 int i;
1441 void *addr;
1443 if (kretprobe_blacklist_size) {
1444 addr = kprobe_addr(&rp->kp);
1445 if (!addr)
1446 return -EINVAL;
1448 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
1449 if (kretprobe_blacklist[i].addr == addr)
1450 return -EINVAL;
1454 rp->kp.pre_handler = pre_handler_kretprobe;
1455 rp->kp.post_handler = NULL;
1456 rp->kp.fault_handler = NULL;
1457 rp->kp.break_handler = NULL;
1459 /* Pre-allocate memory for max kretprobe instances */
1460 if (rp->maxactive <= 0) {
1461 #ifdef CONFIG_PREEMPT
1462 rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());
1463 #else
1464 rp->maxactive = num_possible_cpus();
1465 #endif
1467 spin_lock_init(&rp->lock);
1468 INIT_HLIST_HEAD(&rp->free_instances);
1469 for (i = 0; i < rp->maxactive; i++) {
1470 inst = kmalloc(sizeof(struct kretprobe_instance) +
1471 rp->data_size, GFP_KERNEL);
1472 if (inst == NULL) {
1473 free_rp_inst(rp);
1474 return -ENOMEM;
1476 INIT_HLIST_NODE(&inst->hlist);
1477 hlist_add_head(&inst->hlist, &rp->free_instances);
1480 rp->nmissed = 0;
1481 /* Establish function entry probe point */
1482 ret = register_kprobe(&rp->kp);
1483 if (ret != 0)
1484 free_rp_inst(rp);
1485 return ret;
1487 EXPORT_SYMBOL_GPL(register_kretprobe);
1489 int __kprobes register_kretprobes(struct kretprobe **rps, int num)
1491 int ret = 0, i;
1493 if (num <= 0)
1494 return -EINVAL;
1495 for (i = 0; i < num; i++) {
1496 ret = register_kretprobe(rps[i]);
1497 if (ret < 0) {
1498 if (i > 0)
1499 unregister_kretprobes(rps, i);
1500 break;
1503 return ret;
1505 EXPORT_SYMBOL_GPL(register_kretprobes);
1507 void __kprobes unregister_kretprobe(struct kretprobe *rp)
1509 unregister_kretprobes(&rp, 1);
1511 EXPORT_SYMBOL_GPL(unregister_kretprobe);
1513 void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
1515 int i;
1517 if (num <= 0)
1518 return;
1519 mutex_lock(&kprobe_mutex);
1520 for (i = 0; i < num; i++)
1521 if (__unregister_kprobe_top(&rps[i]->kp) < 0)
1522 rps[i]->kp.addr = NULL;
1523 mutex_unlock(&kprobe_mutex);
1525 synchronize_sched();
1526 for (i = 0; i < num; i++) {
1527 if (rps[i]->kp.addr) {
1528 __unregister_kprobe_bottom(&rps[i]->kp);
1529 cleanup_rp_inst(rps[i]);
1533 EXPORT_SYMBOL_GPL(unregister_kretprobes);
1535 #else /* CONFIG_KRETPROBES */
1536 int __kprobes register_kretprobe(struct kretprobe *rp)
1538 return -ENOSYS;
1540 EXPORT_SYMBOL_GPL(register_kretprobe);
1542 int __kprobes register_kretprobes(struct kretprobe **rps, int num)
1544 return -ENOSYS;
1546 EXPORT_SYMBOL_GPL(register_kretprobes);
1548 void __kprobes unregister_kretprobe(struct kretprobe *rp)
1551 EXPORT_SYMBOL_GPL(unregister_kretprobe);
1553 void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
1556 EXPORT_SYMBOL_GPL(unregister_kretprobes);
1558 static int __kprobes pre_handler_kretprobe(struct kprobe *p,
1559 struct pt_regs *regs)
1561 return 0;
1564 #endif /* CONFIG_KRETPROBES */
1566 /* Set the kprobe gone and remove its instruction buffer. */
1567 static void __kprobes kill_kprobe(struct kprobe *p)
1569 struct kprobe *kp;
1571 p->flags |= KPROBE_FLAG_GONE;
1572 if (kprobe_aggrprobe(p)) {
1574 * If this is an aggr_kprobe, we have to list all the
1575 * chained probes and mark them GONE.
1577 list_for_each_entry_rcu(kp, &p->list, list)
1578 kp->flags |= KPROBE_FLAG_GONE;
1579 p->post_handler = NULL;
1580 p->break_handler = NULL;
1581 kill_optimized_kprobe(p);
1584 * Here, we can remove insn_slot safely, because no thread calls
1585 * the original probed function (which will be freed soon) any more.
1587 arch_remove_kprobe(p);
1590 void __kprobes dump_kprobe(struct kprobe *kp)
1592 printk(KERN_WARNING "Dumping kprobe:\n");
1593 printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n",
1594 kp->symbol_name, kp->addr, kp->offset);
1597 /* Module notifier call back, checking kprobes on the module */
1598 static int __kprobes kprobes_module_callback(struct notifier_block *nb,
1599 unsigned long val, void *data)
1601 struct module *mod = data;
1602 struct hlist_head *head;
1603 struct hlist_node *node;
1604 struct kprobe *p;
1605 unsigned int i;
1606 int checkcore = (val == MODULE_STATE_GOING);
1608 if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
1609 return NOTIFY_DONE;
1612 * When MODULE_STATE_GOING was notified, both of module .text and
1613 * .init.text sections would be freed. When MODULE_STATE_LIVE was
1614 * notified, only .init.text section would be freed. We need to
1615 * disable kprobes which have been inserted in the sections.
1617 mutex_lock(&kprobe_mutex);
1618 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1619 head = &kprobe_table[i];
1620 hlist_for_each_entry_rcu(p, node, head, hlist)
1621 if (within_module_init((unsigned long)p->addr, mod) ||
1622 (checkcore &&
1623 within_module_core((unsigned long)p->addr, mod))) {
1625 * The vaddr this probe is installed will soon
1626 * be vfreed buy not synced to disk. Hence,
1627 * disarming the breakpoint isn't needed.
1629 kill_kprobe(p);
1632 mutex_unlock(&kprobe_mutex);
1633 return NOTIFY_DONE;
1636 static struct notifier_block kprobe_module_nb = {
1637 .notifier_call = kprobes_module_callback,
1638 .priority = 0
1641 static int __init init_kprobes(void)
1643 int i, err = 0;
1644 unsigned long offset = 0, size = 0;
1645 char *modname, namebuf[128];
1646 const char *symbol_name;
1647 void *addr;
1648 struct kprobe_blackpoint *kb;
1650 /* FIXME allocate the probe table, currently defined statically */
1651 /* initialize all list heads */
1652 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1653 INIT_HLIST_HEAD(&kprobe_table[i]);
1654 INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
1655 spin_lock_init(&(kretprobe_table_locks[i].lock));
1659 * Lookup and populate the kprobe_blacklist.
1661 * Unlike the kretprobe blacklist, we'll need to determine
1662 * the range of addresses that belong to the said functions,
1663 * since a kprobe need not necessarily be at the beginning
1664 * of a function.
1666 for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
1667 kprobe_lookup_name(kb->name, addr);
1668 if (!addr)
1669 continue;
1671 kb->start_addr = (unsigned long)addr;
1672 symbol_name = kallsyms_lookup(kb->start_addr,
1673 &size, &offset, &modname, namebuf);
1674 if (!symbol_name)
1675 kb->range = 0;
1676 else
1677 kb->range = size;
1680 if (kretprobe_blacklist_size) {
1681 /* lookup the function address from its name */
1682 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
1683 kprobe_lookup_name(kretprobe_blacklist[i].name,
1684 kretprobe_blacklist[i].addr);
1685 if (!kretprobe_blacklist[i].addr)
1686 printk("kretprobe: lookup failed: %s\n",
1687 kretprobe_blacklist[i].name);
1691 #if defined(CONFIG_OPTPROBES)
1692 #if defined(__ARCH_WANT_KPROBES_INSN_SLOT)
1693 /* Init kprobe_optinsn_slots */
1694 kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
1695 #endif
1696 /* By default, kprobes can be optimized */
1697 kprobes_allow_optimization = true;
1698 #endif
1700 /* By default, kprobes are armed */
1701 kprobes_all_disarmed = false;
1703 err = arch_init_kprobes();
1704 if (!err)
1705 err = register_die_notifier(&kprobe_exceptions_nb);
1706 if (!err)
1707 err = register_module_notifier(&kprobe_module_nb);
1709 kprobes_initialized = (err == 0);
1711 if (!err)
1712 init_test_probes();
1713 return err;
1716 #ifdef CONFIG_DEBUG_FS
1717 static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p,
1718 const char *sym, int offset, char *modname, struct kprobe *pp)
1720 char *kprobe_type;
1722 if (p->pre_handler == pre_handler_kretprobe)
1723 kprobe_type = "r";
1724 else if (p->pre_handler == setjmp_pre_handler)
1725 kprobe_type = "j";
1726 else
1727 kprobe_type = "k";
1729 if (sym)
1730 seq_printf(pi, "%p %s %s+0x%x %s ",
1731 p->addr, kprobe_type, sym, offset,
1732 (modname ? modname : " "));
1733 else
1734 seq_printf(pi, "%p %s %p ",
1735 p->addr, kprobe_type, p->addr);
1737 if (!pp)
1738 pp = p;
1739 seq_printf(pi, "%s%s%s\n",
1740 (kprobe_gone(p) ? "[GONE]" : ""),
1741 ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""),
1742 (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""));
1745 static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos)
1747 return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
1750 static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
1752 (*pos)++;
1753 if (*pos >= KPROBE_TABLE_SIZE)
1754 return NULL;
1755 return pos;
1758 static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v)
1760 /* Nothing to do */
1763 static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v)
1765 struct hlist_head *head;
1766 struct hlist_node *node;
1767 struct kprobe *p, *kp;
1768 const char *sym = NULL;
1769 unsigned int i = *(loff_t *) v;
1770 unsigned long offset = 0;
1771 char *modname, namebuf[128];
1773 head = &kprobe_table[i];
1774 preempt_disable();
1775 hlist_for_each_entry_rcu(p, node, head, hlist) {
1776 sym = kallsyms_lookup((unsigned long)p->addr, NULL,
1777 &offset, &modname, namebuf);
1778 if (kprobe_aggrprobe(p)) {
1779 list_for_each_entry_rcu(kp, &p->list, list)
1780 report_probe(pi, kp, sym, offset, modname, p);
1781 } else
1782 report_probe(pi, p, sym, offset, modname, NULL);
1784 preempt_enable();
1785 return 0;
1788 static const struct seq_operations kprobes_seq_ops = {
1789 .start = kprobe_seq_start,
1790 .next = kprobe_seq_next,
1791 .stop = kprobe_seq_stop,
1792 .show = show_kprobe_addr
1795 static int __kprobes kprobes_open(struct inode *inode, struct file *filp)
1797 return seq_open(filp, &kprobes_seq_ops);
1800 static const struct file_operations debugfs_kprobes_operations = {
1801 .open = kprobes_open,
1802 .read = seq_read,
1803 .llseek = seq_lseek,
1804 .release = seq_release,
1807 /* Disable one kprobe */
1808 int __kprobes disable_kprobe(struct kprobe *kp)
1810 int ret = 0;
1811 struct kprobe *p;
1813 mutex_lock(&kprobe_mutex);
1815 /* Check whether specified probe is valid. */
1816 p = __get_valid_kprobe(kp);
1817 if (unlikely(p == NULL)) {
1818 ret = -EINVAL;
1819 goto out;
1822 /* If the probe is already disabled (or gone), just return */
1823 if (kprobe_disabled(kp))
1824 goto out;
1826 kp->flags |= KPROBE_FLAG_DISABLED;
1827 if (p != kp)
1828 /* When kp != p, p is always enabled. */
1829 try_to_disable_aggr_kprobe(p);
1831 if (!kprobes_all_disarmed && kprobe_disabled(p))
1832 disarm_kprobe(p);
1833 out:
1834 mutex_unlock(&kprobe_mutex);
1835 return ret;
1837 EXPORT_SYMBOL_GPL(disable_kprobe);
1839 /* Enable one kprobe */
1840 int __kprobes enable_kprobe(struct kprobe *kp)
1842 int ret = 0;
1843 struct kprobe *p;
1845 mutex_lock(&kprobe_mutex);
1847 /* Check whether specified probe is valid. */
1848 p = __get_valid_kprobe(kp);
1849 if (unlikely(p == NULL)) {
1850 ret = -EINVAL;
1851 goto out;
1854 if (kprobe_gone(kp)) {
1855 /* This kprobe has gone, we couldn't enable it. */
1856 ret = -EINVAL;
1857 goto out;
1860 if (p != kp)
1861 kp->flags &= ~KPROBE_FLAG_DISABLED;
1863 if (!kprobes_all_disarmed && kprobe_disabled(p)) {
1864 p->flags &= ~KPROBE_FLAG_DISABLED;
1865 arm_kprobe(p);
1867 out:
1868 mutex_unlock(&kprobe_mutex);
1869 return ret;
1871 EXPORT_SYMBOL_GPL(enable_kprobe);
1873 static void __kprobes arm_all_kprobes(void)
1875 struct hlist_head *head;
1876 struct hlist_node *node;
1877 struct kprobe *p;
1878 unsigned int i;
1880 mutex_lock(&kprobe_mutex);
1882 /* If kprobes are armed, just return */
1883 if (!kprobes_all_disarmed)
1884 goto already_enabled;
1886 /* Arming kprobes doesn't optimize kprobe itself */
1887 mutex_lock(&text_mutex);
1888 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1889 head = &kprobe_table[i];
1890 hlist_for_each_entry_rcu(p, node, head, hlist)
1891 if (!kprobe_disabled(p))
1892 __arm_kprobe(p);
1894 mutex_unlock(&text_mutex);
1896 kprobes_all_disarmed = false;
1897 printk(KERN_INFO "Kprobes globally enabled\n");
1899 already_enabled:
1900 mutex_unlock(&kprobe_mutex);
1901 return;
1904 static void __kprobes disarm_all_kprobes(void)
1906 struct hlist_head *head;
1907 struct hlist_node *node;
1908 struct kprobe *p;
1909 unsigned int i;
1911 mutex_lock(&kprobe_mutex);
1913 /* If kprobes are already disarmed, just return */
1914 if (kprobes_all_disarmed)
1915 goto already_disabled;
1917 kprobes_all_disarmed = true;
1918 printk(KERN_INFO "Kprobes globally disabled\n");
1921 * Here we call get_online_cpus() for avoiding text_mutex deadlock,
1922 * because disarming may also unoptimize kprobes.
1924 get_online_cpus();
1925 mutex_lock(&text_mutex);
1926 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1927 head = &kprobe_table[i];
1928 hlist_for_each_entry_rcu(p, node, head, hlist) {
1929 if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p))
1930 __disarm_kprobe(p);
1934 mutex_unlock(&text_mutex);
1935 put_online_cpus();
1936 mutex_unlock(&kprobe_mutex);
1937 /* Allow all currently running kprobes to complete */
1938 synchronize_sched();
1939 return;
1941 already_disabled:
1942 mutex_unlock(&kprobe_mutex);
1943 return;
1947 * XXX: The debugfs bool file interface doesn't allow for callbacks
1948 * when the bool state is switched. We can reuse that facility when
1949 * available
1951 static ssize_t read_enabled_file_bool(struct file *file,
1952 char __user *user_buf, size_t count, loff_t *ppos)
1954 char buf[3];
1956 if (!kprobes_all_disarmed)
1957 buf[0] = '1';
1958 else
1959 buf[0] = '0';
1960 buf[1] = '\n';
1961 buf[2] = 0x00;
1962 return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
1965 static ssize_t write_enabled_file_bool(struct file *file,
1966 const char __user *user_buf, size_t count, loff_t *ppos)
1968 char buf[32];
1969 int buf_size;
1971 buf_size = min(count, (sizeof(buf)-1));
1972 if (copy_from_user(buf, user_buf, buf_size))
1973 return -EFAULT;
1975 switch (buf[0]) {
1976 case 'y':
1977 case 'Y':
1978 case '1':
1979 arm_all_kprobes();
1980 break;
1981 case 'n':
1982 case 'N':
1983 case '0':
1984 disarm_all_kprobes();
1985 break;
1988 return count;
1991 static const struct file_operations fops_kp = {
1992 .read = read_enabled_file_bool,
1993 .write = write_enabled_file_bool,
1996 static int __kprobes debugfs_kprobe_init(void)
1998 struct dentry *dir, *file;
1999 unsigned int value = 1;
2001 dir = debugfs_create_dir("kprobes", NULL);
2002 if (!dir)
2003 return -ENOMEM;
2005 file = debugfs_create_file("list", 0444, dir, NULL,
2006 &debugfs_kprobes_operations);
2007 if (!file) {
2008 debugfs_remove(dir);
2009 return -ENOMEM;
2012 file = debugfs_create_file("enabled", 0600, dir,
2013 &value, &fops_kp);
2014 if (!file) {
2015 debugfs_remove(dir);
2016 return -ENOMEM;
2019 return 0;
2022 late_initcall(debugfs_kprobe_init);
2023 #endif /* CONFIG_DEBUG_FS */
2025 module_init(init_kprobes);
2027 /* defined in arch/.../kernel/kprobes.c */
2028 EXPORT_SYMBOL_GPL(jprobe_return);