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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Kernel Probes (KProbes)
3 * kernel/kprobes.c
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 *
19 * Copyright (C) IBM Corporation, 2002, 2004
20 *
21 * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
22 * Probes initial implementation (includes suggestions from
23 * Rusty Russell).
24 * 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with
25 * hlists and exceptions notifier as suggested by Andi Kleen.
26 * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
27 * interface to access function arguments.
28 * 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes
29 * exceptions notifier to be first on the priority list.
Hien Nguyenb94cce92005-06-23 00:09:19 -070030 * 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.
Linus Torvalds1da177e2005-04-16 15:20:36 -070033 */
34#include <linux/kprobes.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070035#include <linux/hash.h>
36#include <linux/init.h>
Tim Schmielau4e57b682005-10-30 15:03:48 -080037#include <linux/slab.h>
Randy Dunlape3869792007-05-08 00:27:01 -070038#include <linux/stddef.h>
Paul Gortmaker9984de12011-05-23 14:51:41 -040039#include <linux/export.h>
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -070040#include <linux/moduleloader.h>
Ananth N Mavinakayanahalli3a872d82006-10-02 02:17:30 -070041#include <linux/kallsyms.h>
Masami Hiramatsub4c6c342006-12-06 20:38:11 -080042#include <linux/freezer.h>
Srinivasa Ds346fd592007-02-20 13:57:54 -080043#include <linux/seq_file.h>
44#include <linux/debugfs.h>
Masami Hiramatsub2be84d2010-02-25 08:34:15 -050045#include <linux/sysctl.h>
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -070046#include <linux/kdebug.h>
Mathieu Desnoyers4460fda2009-03-06 10:36:38 -050047#include <linux/memory.h>
Masami Hiramatsu4554dbc2010-02-02 16:49:18 -050048#include <linux/ftrace.h>
Masami Hiramatsuafd66252010-02-25 08:34:07 -050049#include <linux/cpu.h>
Jason Baronbf5438fc2010-09-17 11:09:00 -040050#include <linux/jump_label.h>
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -070051
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -070052#include <asm-generic/sections.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070053#include <asm/cacheflush.h>
54#include <asm/errno.h>
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -070055#include <asm/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
57#define KPROBE_HASH_BITS 6
58#define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
59
Ananth N Mavinakayanahalli3a872d82006-10-02 02:17:30 -070060
61/*
62 * Some oddball architectures like 64bit powerpc have function descriptors
63 * so this must be overridable.
64 */
65#ifndef kprobe_lookup_name
66#define kprobe_lookup_name(name, addr) \
67 addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name)))
68#endif
69
Srinivasa D Sef53d9c2008-07-25 01:46:04 -070070static int kprobes_initialized;
Linus Torvalds1da177e2005-04-16 15:20:36 -070071static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
Hien Nguyenb94cce92005-06-23 00:09:19 -070072static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
Linus Torvalds1da177e2005-04-16 15:20:36 -070073
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -070074/* NOTE: change this value only with kprobe_mutex held */
Masami Hiramatsue579abe2009-04-06 19:01:01 -070075static bool kprobes_all_disarmed;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -070076
Masami Hiramatsu43948f52010-10-25 22:18:01 +090077/* This protects kprobe_table and optimizing_list */
78static DEFINE_MUTEX(kprobe_mutex);
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -080079static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
Srinivasa D Sef53d9c2008-07-25 01:46:04 -070080static struct {
Thomas Gleixnerec4846082009-07-25 16:09:17 +020081 raw_spinlock_t lock ____cacheline_aligned_in_smp;
Srinivasa D Sef53d9c2008-07-25 01:46:04 -070082} kretprobe_table_locks[KPROBE_TABLE_SIZE];
83
Thomas Gleixnerec4846082009-07-25 16:09:17 +020084static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
Srinivasa D Sef53d9c2008-07-25 01:46:04 -070085{
86 return &(kretprobe_table_locks[hash].lock);
87}
Linus Torvalds1da177e2005-04-16 15:20:36 -070088
Masami Hiramatsu376e2422014-04-17 17:17:05 +090089/* Blacklist -- list of struct kprobe_blacklist_entry */
90static LIST_HEAD(kprobe_blacklist);
Srinivasa Ds3d8d9962008-04-28 02:14:26 -070091
Anil S Keshavamurthy2d14e392006-01-09 20:52:41 -080092#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -070093/*
94 * kprobe->ainsn.insn points to the copy of the instruction to be
95 * single-stepped. x86_64, POWER4 and above have no-exec support and
96 * stepping on the instruction on a vmalloced/kmalloced/data page
97 * is a recipe for disaster
98 */
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -070099struct kprobe_insn_page {
Masami Hiramatsuc5cb5a22009-06-30 17:08:14 -0400100 struct list_head list;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700101 kprobe_opcode_t *insns; /* Page of instruction slots */
Heiko Carstensaf963972013-09-11 14:24:13 -0700102 struct kprobe_insn_cache *cache;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700103 int nused;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800104 int ngarbage;
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500105 char slot_used[];
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700106};
107
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500108#define KPROBE_INSN_PAGE_SIZE(slots) \
109 (offsetof(struct kprobe_insn_page, slot_used) + \
110 (sizeof(char) * (slots)))
111
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500112static int slots_per_page(struct kprobe_insn_cache *c)
113{
114 return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t));
115}
116
Masami Hiramatsuab40c5c2007-01-30 14:36:06 -0800117enum kprobe_slot_state {
118 SLOT_CLEAN = 0,
119 SLOT_DIRTY = 1,
120 SLOT_USED = 2,
121};
122
Heiko Carstensaf963972013-09-11 14:24:13 -0700123static void *alloc_insn_page(void)
124{
125 return module_alloc(PAGE_SIZE);
126}
127
128static void free_insn_page(void *page)
129{
130 module_free(NULL, page);
131}
132
Heiko Carstensc802d642013-09-11 14:24:11 -0700133struct kprobe_insn_cache kprobe_insn_slots = {
134 .mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex),
Heiko Carstensaf963972013-09-11 14:24:13 -0700135 .alloc = alloc_insn_page,
136 .free = free_insn_page,
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500137 .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages),
138 .insn_size = MAX_INSN_SIZE,
139 .nr_garbage = 0,
140};
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900141static int collect_garbage_slots(struct kprobe_insn_cache *c);
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800142
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700143/**
Masami Hiramatsu12941562009-01-06 14:41:50 -0800144 * __get_insn_slot() - Find a slot on an executable page for an instruction.
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700145 * We allocate an executable page if there's no room on existing ones.
146 */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900147kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c)
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700148{
149 struct kprobe_insn_page *kip;
Heiko Carstensc802d642013-09-11 14:24:11 -0700150 kprobe_opcode_t *slot = NULL;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700151
Heiko Carstensc802d642013-09-11 14:24:11 -0700152 mutex_lock(&c->mutex);
Christoph Hellwig6f716ac2007-05-08 00:34:13 -0700153 retry:
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500154 list_for_each_entry(kip, &c->pages, list) {
155 if (kip->nused < slots_per_page(c)) {
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700156 int i;
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500157 for (i = 0; i < slots_per_page(c); i++) {
Masami Hiramatsuab40c5c2007-01-30 14:36:06 -0800158 if (kip->slot_used[i] == SLOT_CLEAN) {
159 kip->slot_used[i] = SLOT_USED;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700160 kip->nused++;
Heiko Carstensc802d642013-09-11 14:24:11 -0700161 slot = kip->insns + (i * c->insn_size);
162 goto out;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700163 }
164 }
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500165 /* kip->nused is broken. Fix it. */
166 kip->nused = slots_per_page(c);
167 WARN_ON(1);
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700168 }
169 }
170
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800171 /* If there are any garbage slots, collect it and try again. */
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500172 if (c->nr_garbage && collect_garbage_slots(c) == 0)
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800173 goto retry;
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500174
175 /* All out of space. Need to allocate a new page. */
176 kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL);
Christoph Hellwig6f716ac2007-05-08 00:34:13 -0700177 if (!kip)
Heiko Carstensc802d642013-09-11 14:24:11 -0700178 goto out;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700179
180 /*
181 * Use module_alloc so this page is within +/- 2GB of where the
182 * kernel image and loaded module images reside. This is required
183 * so x86_64 can correctly handle the %rip-relative fixups.
184 */
Heiko Carstensaf963972013-09-11 14:24:13 -0700185 kip->insns = c->alloc();
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700186 if (!kip->insns) {
187 kfree(kip);
Heiko Carstensc802d642013-09-11 14:24:11 -0700188 goto out;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700189 }
Masami Hiramatsuc5cb5a22009-06-30 17:08:14 -0400190 INIT_LIST_HEAD(&kip->list);
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500191 memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c));
Masami Hiramatsuab40c5c2007-01-30 14:36:06 -0800192 kip->slot_used[0] = SLOT_USED;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700193 kip->nused = 1;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800194 kip->ngarbage = 0;
Heiko Carstensaf963972013-09-11 14:24:13 -0700195 kip->cache = c;
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500196 list_add(&kip->list, &c->pages);
Heiko Carstensc802d642013-09-11 14:24:11 -0700197 slot = kip->insns;
198out:
199 mutex_unlock(&c->mutex);
200 return slot;
Masami Hiramatsu12941562009-01-06 14:41:50 -0800201}
202
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800203/* Return 1 if all garbages are collected, otherwise 0. */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900204static int collect_one_slot(struct kprobe_insn_page *kip, int idx)
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800205{
Masami Hiramatsuab40c5c2007-01-30 14:36:06 -0800206 kip->slot_used[idx] = SLOT_CLEAN;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800207 kip->nused--;
208 if (kip->nused == 0) {
209 /*
210 * Page is no longer in use. Free it unless
211 * it's the last one. We keep the last one
212 * so as not to have to set it up again the
213 * next time somebody inserts a probe.
214 */
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500215 if (!list_is_singular(&kip->list)) {
Masami Hiramatsuc5cb5a22009-06-30 17:08:14 -0400216 list_del(&kip->list);
Heiko Carstensaf963972013-09-11 14:24:13 -0700217 kip->cache->free(kip->insns);
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800218 kfree(kip);
219 }
220 return 1;
221 }
222 return 0;
223}
224
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900225static int collect_garbage_slots(struct kprobe_insn_cache *c)
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800226{
Masami Hiramatsuc5cb5a22009-06-30 17:08:14 -0400227 struct kprobe_insn_page *kip, *next;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800228
Masami Hiramatsu615d0eb2010-02-02 16:49:04 -0500229 /* Ensure no-one is interrupted on the garbages */
230 synchronize_sched();
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800231
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500232 list_for_each_entry_safe(kip, next, &c->pages, list) {
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800233 int i;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800234 if (kip->ngarbage == 0)
235 continue;
236 kip->ngarbage = 0; /* we will collect all garbages */
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500237 for (i = 0; i < slots_per_page(c); i++) {
Masami Hiramatsuab40c5c2007-01-30 14:36:06 -0800238 if (kip->slot_used[i] == SLOT_DIRTY &&
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800239 collect_one_slot(kip, i))
240 break;
241 }
242 }
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500243 c->nr_garbage = 0;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800244 return 0;
245}
246
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900247void __free_insn_slot(struct kprobe_insn_cache *c,
248 kprobe_opcode_t *slot, int dirty)
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500249{
250 struct kprobe_insn_page *kip;
251
Heiko Carstensc802d642013-09-11 14:24:11 -0700252 mutex_lock(&c->mutex);
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500253 list_for_each_entry(kip, &c->pages, list) {
Masami Hiramatsu83ff56f2010-03-09 10:22:19 -0500254 long idx = ((long)slot - (long)kip->insns) /
255 (c->insn_size * sizeof(kprobe_opcode_t));
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500256 if (idx >= 0 && idx < slots_per_page(c)) {
257 WARN_ON(kip->slot_used[idx] != SLOT_USED);
258 if (dirty) {
259 kip->slot_used[idx] = SLOT_DIRTY;
260 kip->ngarbage++;
261 if (++c->nr_garbage > slots_per_page(c))
262 collect_garbage_slots(c);
263 } else
264 collect_one_slot(kip, idx);
Heiko Carstensc802d642013-09-11 14:24:11 -0700265 goto out;
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500266 }
267 }
268 /* Could not free this slot. */
269 WARN_ON(1);
Heiko Carstensc802d642013-09-11 14:24:11 -0700270out:
271 mutex_unlock(&c->mutex);
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500272}
273
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500274#ifdef CONFIG_OPTPROBES
275/* For optimized_kprobe buffer */
Heiko Carstensc802d642013-09-11 14:24:11 -0700276struct kprobe_insn_cache kprobe_optinsn_slots = {
277 .mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex),
Heiko Carstensaf963972013-09-11 14:24:13 -0700278 .alloc = alloc_insn_page,
279 .free = free_insn_page,
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500280 .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
281 /* .insn_size is initialized later */
282 .nr_garbage = 0,
283};
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500284#endif
Anil S Keshavamurthy2d14e392006-01-09 20:52:41 -0800285#endif
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700286
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800287/* We have preemption disabled.. so it is safe to use __ versions */
288static inline void set_kprobe_instance(struct kprobe *kp)
289{
Christoph Lameterb76834b2010-12-06 11:16:25 -0600290 __this_cpu_write(kprobe_instance, kp);
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800291}
292
293static inline void reset_kprobe_instance(void)
294{
Christoph Lameterb76834b2010-12-06 11:16:25 -0600295 __this_cpu_write(kprobe_instance, NULL);
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800296}
297
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800298/*
299 * This routine is called either:
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -0800300 * - under the kprobe_mutex - during kprobe_[un]register()
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800301 * OR
Ananth N Mavinakayanahallid217d542005-11-07 01:00:14 -0800302 * - with preemption disabled - from arch/xxx/kernel/kprobes.c
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800303 */
Masami Hiramatsu820aede2014-04-17 17:18:21 +0900304struct kprobe *get_kprobe(void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305{
306 struct hlist_head *head;
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800307 struct kprobe *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308
309 head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
Sasha Levinb67bfe02013-02-27 17:06:00 -0800310 hlist_for_each_entry_rcu(p, head, hlist) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 if (p->addr == addr)
312 return p;
313 }
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500314
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 return NULL;
316}
Masami Hiramatsu820aede2014-04-17 17:18:21 +0900317NOKPROBE_SYMBOL(get_kprobe);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318
Masami Hiramatsu820aede2014-04-17 17:18:21 +0900319static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs);
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500320
321/* Return true if the kprobe is an aggregator */
322static inline int kprobe_aggrprobe(struct kprobe *p)
323{
324 return p->pre_handler == aggr_pre_handler;
325}
326
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900327/* Return true(!0) if the kprobe is unused */
328static inline int kprobe_unused(struct kprobe *p)
329{
330 return kprobe_aggrprobe(p) && kprobe_disabled(p) &&
331 list_empty(&p->list);
332}
333
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500334/*
335 * Keep all fields in the kprobe consistent
336 */
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +0900337static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500338{
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +0900339 memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t));
340 memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn));
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500341}
342
343#ifdef CONFIG_OPTPROBES
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500344/* NOTE: change this value only with kprobe_mutex held */
345static bool kprobes_allow_optimization;
346
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500347/*
348 * Call all pre_handler on the list, but ignores its return value.
349 * This must be called from arch-dep optimized caller.
350 */
Masami Hiramatsu820aede2014-04-17 17:18:21 +0900351void opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500352{
353 struct kprobe *kp;
354
355 list_for_each_entry_rcu(kp, &p->list, list) {
356 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
357 set_kprobe_instance(kp);
358 kp->pre_handler(kp, regs);
359 }
360 reset_kprobe_instance();
361 }
362}
Masami Hiramatsu820aede2014-04-17 17:18:21 +0900363NOKPROBE_SYMBOL(opt_pre_handler);
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500364
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900365/* Free optimized instructions and optimized_kprobe */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900366static void free_aggr_kprobe(struct kprobe *p)
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900367{
368 struct optimized_kprobe *op;
369
370 op = container_of(p, struct optimized_kprobe, kp);
371 arch_remove_optimized_kprobe(op);
372 arch_remove_kprobe(p);
373 kfree(op);
374}
375
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500376/* Return true(!0) if the kprobe is ready for optimization. */
377static inline int kprobe_optready(struct kprobe *p)
378{
379 struct optimized_kprobe *op;
380
381 if (kprobe_aggrprobe(p)) {
382 op = container_of(p, struct optimized_kprobe, kp);
383 return arch_prepared_optinsn(&op->optinsn);
384 }
385
386 return 0;
387}
388
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900389/* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */
390static inline int kprobe_disarmed(struct kprobe *p)
391{
392 struct optimized_kprobe *op;
393
394 /* If kprobe is not aggr/opt probe, just return kprobe is disabled */
395 if (!kprobe_aggrprobe(p))
396 return kprobe_disabled(p);
397
398 op = container_of(p, struct optimized_kprobe, kp);
399
400 return kprobe_disabled(p) && list_empty(&op->list);
401}
402
403/* Return true(!0) if the probe is queued on (un)optimizing lists */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900404static int kprobe_queued(struct kprobe *p)
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900405{
406 struct optimized_kprobe *op;
407
408 if (kprobe_aggrprobe(p)) {
409 op = container_of(p, struct optimized_kprobe, kp);
410 if (!list_empty(&op->list))
411 return 1;
412 }
413 return 0;
414}
415
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500416/*
417 * Return an optimized kprobe whose optimizing code replaces
418 * instructions including addr (exclude breakpoint).
419 */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900420static struct kprobe *get_optimized_kprobe(unsigned long addr)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500421{
422 int i;
423 struct kprobe *p = NULL;
424 struct optimized_kprobe *op;
425
426 /* Don't check i == 0, since that is a breakpoint case. */
427 for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++)
428 p = get_kprobe((void *)(addr - i));
429
430 if (p && kprobe_optready(p)) {
431 op = container_of(p, struct optimized_kprobe, kp);
432 if (arch_within_optimized_kprobe(op, addr))
433 return p;
434 }
435
436 return NULL;
437}
438
439/* Optimization staging list, protected by kprobe_mutex */
440static LIST_HEAD(optimizing_list);
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900441static LIST_HEAD(unoptimizing_list);
Masami Hiramatsu7b959fc2013-05-22 18:34:09 +0900442static LIST_HEAD(freeing_list);
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500443
444static void kprobe_optimizer(struct work_struct *work);
445static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
446#define OPTIMIZE_DELAY 5
447
Masami Hiramatsu61f4e132010-12-03 18:54:03 +0900448/*
449 * Optimize (replace a breakpoint with a jump) kprobes listed on
450 * optimizing_list.
451 */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900452static void do_optimize_kprobes(void)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500453{
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900454 /* Optimization never be done when disarmed */
455 if (kprobes_all_disarmed || !kprobes_allow_optimization ||
456 list_empty(&optimizing_list))
457 return;
458
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500459 /*
460 * The optimization/unoptimization refers online_cpus via
461 * stop_machine() and cpu-hotplug modifies online_cpus.
462 * And same time, text_mutex will be held in cpu-hotplug and here.
463 * This combination can cause a deadlock (cpu-hotplug try to lock
464 * text_mutex but stop_machine can not be done because online_cpus
465 * has been changed)
466 * To avoid this deadlock, we need to call get_online_cpus()
467 * for preventing cpu-hotplug outside of text_mutex locking.
468 */
469 get_online_cpus();
470 mutex_lock(&text_mutex);
Masami Hiramatsucd7ebe22010-12-03 18:54:28 +0900471 arch_optimize_kprobes(&optimizing_list);
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500472 mutex_unlock(&text_mutex);
473 put_online_cpus();
Masami Hiramatsu61f4e132010-12-03 18:54:03 +0900474}
475
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900476/*
477 * Unoptimize (replace a jump with a breakpoint and remove the breakpoint
478 * if need) kprobes listed on unoptimizing_list.
479 */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900480static void do_unoptimize_kprobes(void)
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900481{
482 struct optimized_kprobe *op, *tmp;
483
484 /* Unoptimization must be done anytime */
485 if (list_empty(&unoptimizing_list))
486 return;
487
488 /* Ditto to do_optimize_kprobes */
489 get_online_cpus();
490 mutex_lock(&text_mutex);
Masami Hiramatsu7b959fc2013-05-22 18:34:09 +0900491 arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list);
Masami Hiramatsuf984ba42010-12-03 18:54:34 +0900492 /* Loop free_list for disarming */
Masami Hiramatsu7b959fc2013-05-22 18:34:09 +0900493 list_for_each_entry_safe(op, tmp, &freeing_list, list) {
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900494 /* Disarm probes if marked disabled */
495 if (kprobe_disabled(&op->kp))
496 arch_disarm_kprobe(&op->kp);
497 if (kprobe_unused(&op->kp)) {
498 /*
499 * Remove unused probes from hash list. After waiting
500 * for synchronization, these probes are reclaimed.
501 * (reclaiming is done by do_free_cleaned_kprobes.)
502 */
503 hlist_del_rcu(&op->kp.hlist);
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900504 } else
505 list_del_init(&op->list);
506 }
507 mutex_unlock(&text_mutex);
508 put_online_cpus();
509}
510
511/* Reclaim all kprobes on the free_list */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900512static void do_free_cleaned_kprobes(void)
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900513{
514 struct optimized_kprobe *op, *tmp;
515
Masami Hiramatsu7b959fc2013-05-22 18:34:09 +0900516 list_for_each_entry_safe(op, tmp, &freeing_list, list) {
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900517 BUG_ON(!kprobe_unused(&op->kp));
518 list_del_init(&op->list);
519 free_aggr_kprobe(&op->kp);
520 }
521}
522
523/* Start optimizer after OPTIMIZE_DELAY passed */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900524static void kick_kprobe_optimizer(void)
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900525{
Tejun Heoad72b3b2012-12-21 17:57:00 -0800526 schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900527}
528
Masami Hiramatsu61f4e132010-12-03 18:54:03 +0900529/* Kprobe jump optimizer */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900530static void kprobe_optimizer(struct work_struct *work)
Masami Hiramatsu61f4e132010-12-03 18:54:03 +0900531{
Steven Rostedt72ef3792012-06-05 19:28:14 +0900532 mutex_lock(&kprobe_mutex);
Masami Hiramatsu61f4e132010-12-03 18:54:03 +0900533 /* Lock modules while optimizing kprobes */
534 mutex_lock(&module_mutex);
Masami Hiramatsu61f4e132010-12-03 18:54:03 +0900535
536 /*
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900537 * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
538 * kprobes before waiting for quiesence period.
539 */
Masami Hiramatsu7b959fc2013-05-22 18:34:09 +0900540 do_unoptimize_kprobes();
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900541
542 /*
543 * Step 2: Wait for quiesence period to ensure all running interrupts
Masami Hiramatsu61f4e132010-12-03 18:54:03 +0900544 * are done. Because optprobe may modify multiple instructions
545 * there is a chance that Nth instruction is interrupted. In that
546 * case, running interrupt can return to 2nd-Nth byte of jump
547 * instruction. This wait is for avoiding it.
548 */
549 synchronize_sched();
550
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900551 /* Step 3: Optimize kprobes after quiesence period */
Masami Hiramatsu61f4e132010-12-03 18:54:03 +0900552 do_optimize_kprobes();
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900553
554 /* Step 4: Free cleaned kprobes after quiesence period */
Masami Hiramatsu7b959fc2013-05-22 18:34:09 +0900555 do_free_cleaned_kprobes();
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900556
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500557 mutex_unlock(&module_mutex);
Steven Rostedt72ef3792012-06-05 19:28:14 +0900558 mutex_unlock(&kprobe_mutex);
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900559
Masami Hiramatsucd7ebe22010-12-03 18:54:28 +0900560 /* Step 5: Kick optimizer again if needed */
Masami Hiramatsuf984ba42010-12-03 18:54:34 +0900561 if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
Masami Hiramatsucd7ebe22010-12-03 18:54:28 +0900562 kick_kprobe_optimizer();
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900563}
564
565/* Wait for completing optimization and unoptimization */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900566static void wait_for_kprobe_optimizer(void)
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900567{
Tejun Heoad72b3b2012-12-21 17:57:00 -0800568 mutex_lock(&kprobe_mutex);
569
570 while (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) {
571 mutex_unlock(&kprobe_mutex);
572
573 /* this will also make optimizing_work execute immmediately */
574 flush_delayed_work(&optimizing_work);
575 /* @optimizing_work might not have been queued yet, relax */
576 cpu_relax();
577
578 mutex_lock(&kprobe_mutex);
579 }
580
581 mutex_unlock(&kprobe_mutex);
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500582}
583
584/* Optimize kprobe if p is ready to be optimized */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900585static void optimize_kprobe(struct kprobe *p)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500586{
587 struct optimized_kprobe *op;
588
589 /* Check if the kprobe is disabled or not ready for optimization. */
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500590 if (!kprobe_optready(p) || !kprobes_allow_optimization ||
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500591 (kprobe_disabled(p) || kprobes_all_disarmed))
592 return;
593
594 /* Both of break_handler and post_handler are not supported. */
595 if (p->break_handler || p->post_handler)
596 return;
597
598 op = container_of(p, struct optimized_kprobe, kp);
599
600 /* Check there is no other kprobes at the optimized instructions */
601 if (arch_check_optimized_kprobe(op) < 0)
602 return;
603
604 /* Check if it is already optimized. */
605 if (op->kp.flags & KPROBE_FLAG_OPTIMIZED)
606 return;
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500607 op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900608
609 if (!list_empty(&op->list))
610 /* This is under unoptimizing. Just dequeue the probe */
611 list_del_init(&op->list);
612 else {
613 list_add(&op->list, &optimizing_list);
614 kick_kprobe_optimizer();
615 }
616}
617
618/* Short cut to direct unoptimizing */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900619static void force_unoptimize_kprobe(struct optimized_kprobe *op)
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900620{
621 get_online_cpus();
622 arch_unoptimize_kprobe(op);
623 put_online_cpus();
624 if (kprobe_disabled(&op->kp))
625 arch_disarm_kprobe(&op->kp);
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500626}
627
628/* Unoptimize a kprobe if p is optimized */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900629static void unoptimize_kprobe(struct kprobe *p, bool force)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500630{
631 struct optimized_kprobe *op;
632
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900633 if (!kprobe_aggrprobe(p) || kprobe_disarmed(p))
634 return; /* This is not an optprobe nor optimized */
635
636 op = container_of(p, struct optimized_kprobe, kp);
637 if (!kprobe_optimized(p)) {
638 /* Unoptimized or unoptimizing case */
639 if (force && !list_empty(&op->list)) {
640 /*
641 * Only if this is unoptimizing kprobe and forced,
642 * forcibly unoptimize it. (No need to unoptimize
643 * unoptimized kprobe again :)
644 */
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500645 list_del_init(&op->list);
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900646 force_unoptimize_kprobe(op);
647 }
648 return;
649 }
650
651 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
652 if (!list_empty(&op->list)) {
653 /* Dequeue from the optimization queue */
654 list_del_init(&op->list);
655 return;
656 }
657 /* Optimized kprobe case */
658 if (force)
659 /* Forcibly update the code: this is a special case */
660 force_unoptimize_kprobe(op);
661 else {
662 list_add(&op->list, &unoptimizing_list);
663 kick_kprobe_optimizer();
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500664 }
665}
666
Masami Hiramatsu0490cd12010-12-03 18:54:16 +0900667/* Cancel unoptimizing for reusing */
668static void reuse_unused_kprobe(struct kprobe *ap)
669{
670 struct optimized_kprobe *op;
671
672 BUG_ON(!kprobe_unused(ap));
673 /*
674 * Unused kprobe MUST be on the way of delayed unoptimizing (means
675 * there is still a relative jump) and disabled.
676 */
677 op = container_of(ap, struct optimized_kprobe, kp);
678 if (unlikely(list_empty(&op->list)))
679 printk(KERN_WARNING "Warning: found a stray unused "
680 "aggrprobe@%p\n", ap->addr);
681 /* Enable the probe again */
682 ap->flags &= ~KPROBE_FLAG_DISABLED;
683 /* Optimize it again (remove from op->list) */
684 BUG_ON(!kprobe_optready(ap));
685 optimize_kprobe(ap);
686}
687
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500688/* Remove optimized instructions */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900689static void kill_optimized_kprobe(struct kprobe *p)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500690{
691 struct optimized_kprobe *op;
692
693 op = container_of(p, struct optimized_kprobe, kp);
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900694 if (!list_empty(&op->list))
695 /* Dequeue from the (un)optimization queue */
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500696 list_del_init(&op->list);
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900697 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
Masami Hiramatsu7b959fc2013-05-22 18:34:09 +0900698
699 if (kprobe_unused(p)) {
700 /* Enqueue if it is unused */
701 list_add(&op->list, &freeing_list);
702 /*
703 * Remove unused probes from the hash list. After waiting
704 * for synchronization, this probe is reclaimed.
705 * (reclaiming is done by do_free_cleaned_kprobes().)
706 */
707 hlist_del_rcu(&op->kp.hlist);
708 }
709
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900710 /* Don't touch the code, because it is already freed. */
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500711 arch_remove_optimized_kprobe(op);
712}
713
714/* Try to prepare optimized instructions */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900715static void prepare_optimized_kprobe(struct kprobe *p)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500716{
717 struct optimized_kprobe *op;
718
719 op = container_of(p, struct optimized_kprobe, kp);
720 arch_prepare_optimized_kprobe(op);
721}
722
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500723/* Allocate new optimized_kprobe and try to prepare optimized instructions */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900724static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500725{
726 struct optimized_kprobe *op;
727
728 op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL);
729 if (!op)
730 return NULL;
731
732 INIT_LIST_HEAD(&op->list);
733 op->kp.addr = p->addr;
734 arch_prepare_optimized_kprobe(op);
735
736 return &op->kp;
737}
738
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900739static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p);
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500740
741/*
742 * Prepare an optimized_kprobe and optimize it
743 * NOTE: p must be a normal registered kprobe
744 */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900745static void try_to_optimize_kprobe(struct kprobe *p)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500746{
747 struct kprobe *ap;
748 struct optimized_kprobe *op;
749
Masami Hiramatsuae6aa162012-06-05 19:28:32 +0900750 /* Impossible to optimize ftrace-based kprobe */
751 if (kprobe_ftrace(p))
752 return;
753
Masami Hiramatsu25764282012-06-05 19:28:26 +0900754 /* For preparing optimization, jump_label_text_reserved() is called */
755 jump_label_lock();
756 mutex_lock(&text_mutex);
757
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500758 ap = alloc_aggr_kprobe(p);
759 if (!ap)
Masami Hiramatsu25764282012-06-05 19:28:26 +0900760 goto out;
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500761
762 op = container_of(ap, struct optimized_kprobe, kp);
763 if (!arch_prepared_optinsn(&op->optinsn)) {
764 /* If failed to setup optimizing, fallback to kprobe */
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900765 arch_remove_optimized_kprobe(op);
766 kfree(op);
Masami Hiramatsu25764282012-06-05 19:28:26 +0900767 goto out;
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500768 }
769
770 init_aggr_kprobe(ap, p);
Masami Hiramatsu25764282012-06-05 19:28:26 +0900771 optimize_kprobe(ap); /* This just kicks optimizer thread */
772
773out:
774 mutex_unlock(&text_mutex);
775 jump_label_unlock();
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500776}
777
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500778#ifdef CONFIG_SYSCTL
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900779static void optimize_all_kprobes(void)
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500780{
781 struct hlist_head *head;
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500782 struct kprobe *p;
783 unsigned int i;
784
Masami Hiramatsu5c515432013-04-18 18:33:18 +0900785 mutex_lock(&kprobe_mutex);
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500786 /* If optimization is already allowed, just return */
787 if (kprobes_allow_optimization)
Masami Hiramatsu5c515432013-04-18 18:33:18 +0900788 goto out;
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500789
790 kprobes_allow_optimization = true;
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500791 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
792 head = &kprobe_table[i];
Sasha Levinb67bfe02013-02-27 17:06:00 -0800793 hlist_for_each_entry_rcu(p, head, hlist)
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500794 if (!kprobe_disabled(p))
795 optimize_kprobe(p);
796 }
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500797 printk(KERN_INFO "Kprobes globally optimized\n");
Masami Hiramatsu5c515432013-04-18 18:33:18 +0900798out:
799 mutex_unlock(&kprobe_mutex);
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500800}
801
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900802static void unoptimize_all_kprobes(void)
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500803{
804 struct hlist_head *head;
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500805 struct kprobe *p;
806 unsigned int i;
807
Masami Hiramatsu5c515432013-04-18 18:33:18 +0900808 mutex_lock(&kprobe_mutex);
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500809 /* If optimization is already prohibited, just return */
Masami Hiramatsu5c515432013-04-18 18:33:18 +0900810 if (!kprobes_allow_optimization) {
811 mutex_unlock(&kprobe_mutex);
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500812 return;
Masami Hiramatsu5c515432013-04-18 18:33:18 +0900813 }
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500814
815 kprobes_allow_optimization = false;
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500816 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
817 head = &kprobe_table[i];
Sasha Levinb67bfe02013-02-27 17:06:00 -0800818 hlist_for_each_entry_rcu(p, head, hlist) {
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500819 if (!kprobe_disabled(p))
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900820 unoptimize_kprobe(p, false);
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500821 }
822 }
Masami Hiramatsu5c515432013-04-18 18:33:18 +0900823 mutex_unlock(&kprobe_mutex);
824
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900825 /* Wait for unoptimizing completion */
826 wait_for_kprobe_optimizer();
827 printk(KERN_INFO "Kprobes globally unoptimized\n");
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500828}
829
Masami Hiramatsu5c515432013-04-18 18:33:18 +0900830static DEFINE_MUTEX(kprobe_sysctl_mutex);
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500831int sysctl_kprobes_optimization;
832int proc_kprobes_optimization_handler(struct ctl_table *table, int write,
833 void __user *buffer, size_t *length,
834 loff_t *ppos)
835{
836 int ret;
837
Masami Hiramatsu5c515432013-04-18 18:33:18 +0900838 mutex_lock(&kprobe_sysctl_mutex);
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500839 sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0;
840 ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
841
842 if (sysctl_kprobes_optimization)
843 optimize_all_kprobes();
844 else
845 unoptimize_all_kprobes();
Masami Hiramatsu5c515432013-04-18 18:33:18 +0900846 mutex_unlock(&kprobe_sysctl_mutex);
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500847
848 return ret;
849}
850#endif /* CONFIG_SYSCTL */
851
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900852/* Put a breakpoint for a probe. Must be called with text_mutex locked */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900853static void __arm_kprobe(struct kprobe *p)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500854{
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +0900855 struct kprobe *_p;
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500856
857 /* Check collision with other optimized kprobes */
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +0900858 _p = get_optimized_kprobe((unsigned long)p->addr);
859 if (unlikely(_p))
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900860 /* Fallback to unoptimized kprobe */
861 unoptimize_kprobe(_p, true);
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500862
863 arch_arm_kprobe(p);
864 optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */
865}
866
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900867/* Remove the breakpoint of a probe. Must be called with text_mutex locked */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900868static void __disarm_kprobe(struct kprobe *p, bool reopt)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500869{
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +0900870 struct kprobe *_p;
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500871
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900872 unoptimize_kprobe(p, false); /* Try to unoptimize */
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500873
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900874 if (!kprobe_queued(p)) {
875 arch_disarm_kprobe(p);
876 /* If another kprobe was blocked, optimize it. */
877 _p = get_optimized_kprobe((unsigned long)p->addr);
878 if (unlikely(_p) && reopt)
879 optimize_kprobe(_p);
880 }
881 /* TODO: reoptimize others after unoptimized this probe */
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500882}
883
884#else /* !CONFIG_OPTPROBES */
885
886#define optimize_kprobe(p) do {} while (0)
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900887#define unoptimize_kprobe(p, f) do {} while (0)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500888#define kill_optimized_kprobe(p) do {} while (0)
889#define prepare_optimized_kprobe(p) do {} while (0)
890#define try_to_optimize_kprobe(p) do {} while (0)
891#define __arm_kprobe(p) arch_arm_kprobe(p)
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900892#define __disarm_kprobe(p, o) arch_disarm_kprobe(p)
893#define kprobe_disarmed(p) kprobe_disabled(p)
894#define wait_for_kprobe_optimizer() do {} while (0)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500895
Masami Hiramatsu0490cd12010-12-03 18:54:16 +0900896/* There should be no unused kprobes can be reused without optimization */
897static void reuse_unused_kprobe(struct kprobe *ap)
898{
899 printk(KERN_ERR "Error: There should be no unused kprobe here.\n");
900 BUG_ON(kprobe_unused(ap));
901}
902
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900903static void free_aggr_kprobe(struct kprobe *p)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500904{
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900905 arch_remove_kprobe(p);
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500906 kfree(p);
907}
908
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900909static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500910{
911 return kzalloc(sizeof(struct kprobe), GFP_KERNEL);
912}
913#endif /* CONFIG_OPTPROBES */
914
Masami Hiramatsue7dbfe32012-09-28 17:15:20 +0900915#ifdef CONFIG_KPROBES_ON_FTRACE
Masami Hiramatsuae6aa162012-06-05 19:28:32 +0900916static struct ftrace_ops kprobe_ftrace_ops __read_mostly = {
Masami Hiramatsue5253892012-06-05 19:28:38 +0900917 .func = kprobe_ftrace_handler,
Masami Hiramatsuae6aa162012-06-05 19:28:32 +0900918 .flags = FTRACE_OPS_FL_SAVE_REGS,
919};
920static int kprobe_ftrace_enabled;
921
922/* Must ensure p->addr is really on ftrace */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900923static int prepare_kprobe(struct kprobe *p)
Masami Hiramatsuae6aa162012-06-05 19:28:32 +0900924{
925 if (!kprobe_ftrace(p))
926 return arch_prepare_kprobe(p);
927
928 return arch_prepare_kprobe_ftrace(p);
929}
930
931/* Caller must lock kprobe_mutex */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900932static void arm_kprobe_ftrace(struct kprobe *p)
Masami Hiramatsuae6aa162012-06-05 19:28:32 +0900933{
934 int ret;
935
936 ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
937 (unsigned long)p->addr, 0, 0);
938 WARN(ret < 0, "Failed to arm kprobe-ftrace at %p (%d)\n", p->addr, ret);
939 kprobe_ftrace_enabled++;
940 if (kprobe_ftrace_enabled == 1) {
941 ret = register_ftrace_function(&kprobe_ftrace_ops);
942 WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret);
943 }
944}
945
946/* Caller must lock kprobe_mutex */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900947static void disarm_kprobe_ftrace(struct kprobe *p)
Masami Hiramatsuae6aa162012-06-05 19:28:32 +0900948{
949 int ret;
950
951 kprobe_ftrace_enabled--;
952 if (kprobe_ftrace_enabled == 0) {
953 ret = unregister_ftrace_function(&kprobe_ftrace_ops);
954 WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret);
955 }
956 ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
957 (unsigned long)p->addr, 1, 0);
958 WARN(ret < 0, "Failed to disarm kprobe-ftrace at %p (%d)\n", p->addr, ret);
959}
Masami Hiramatsue7dbfe32012-09-28 17:15:20 +0900960#else /* !CONFIG_KPROBES_ON_FTRACE */
Masami Hiramatsuae6aa162012-06-05 19:28:32 +0900961#define prepare_kprobe(p) arch_prepare_kprobe(p)
962#define arm_kprobe_ftrace(p) do {} while (0)
963#define disarm_kprobe_ftrace(p) do {} while (0)
964#endif
965
Masami Hiramatsu201517a2009-05-07 16:31:26 -0400966/* Arm a kprobe with text_mutex */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900967static void arm_kprobe(struct kprobe *kp)
Masami Hiramatsu201517a2009-05-07 16:31:26 -0400968{
Masami Hiramatsuae6aa162012-06-05 19:28:32 +0900969 if (unlikely(kprobe_ftrace(kp))) {
970 arm_kprobe_ftrace(kp);
971 return;
972 }
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500973 /*
974 * Here, since __arm_kprobe() doesn't use stop_machine(),
975 * this doesn't cause deadlock on text_mutex. So, we don't
976 * need get_online_cpus().
977 */
Masami Hiramatsu201517a2009-05-07 16:31:26 -0400978 mutex_lock(&text_mutex);
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500979 __arm_kprobe(kp);
Masami Hiramatsu201517a2009-05-07 16:31:26 -0400980 mutex_unlock(&text_mutex);
981}
982
983/* Disarm a kprobe with text_mutex */
Masami Hiramatsu55479f62014-04-17 17:17:54 +0900984static void disarm_kprobe(struct kprobe *kp, bool reopt)
Masami Hiramatsu201517a2009-05-07 16:31:26 -0400985{
Masami Hiramatsuae6aa162012-06-05 19:28:32 +0900986 if (unlikely(kprobe_ftrace(kp))) {
987 disarm_kprobe_ftrace(kp);
988 return;
989 }
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900990 /* Ditto */
Masami Hiramatsu201517a2009-05-07 16:31:26 -0400991 mutex_lock(&text_mutex);
Masami Hiramatsuae6aa162012-06-05 19:28:32 +0900992 __disarm_kprobe(kp, reopt);
Masami Hiramatsu201517a2009-05-07 16:31:26 -0400993 mutex_unlock(&text_mutex);
994}
995
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700996/*
997 * Aggregate handlers for multiple kprobes support - these handlers
998 * take care of invoking the individual kprobe handlers on p->list
999 */
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001000static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001001{
1002 struct kprobe *kp;
1003
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -08001004 list_for_each_entry_rcu(kp, &p->list, list) {
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001005 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -08001006 set_kprobe_instance(kp);
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -07001007 if (kp->pre_handler(kp, regs))
1008 return 1;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001009 }
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -08001010 reset_kprobe_instance();
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001011 }
1012 return 0;
1013}
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001014NOKPROBE_SYMBOL(aggr_pre_handler);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001015
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001016static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
1017 unsigned long flags)
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001018{
1019 struct kprobe *kp;
1020
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -08001021 list_for_each_entry_rcu(kp, &p->list, list) {
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001022 if (kp->post_handler && likely(!kprobe_disabled(kp))) {
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -08001023 set_kprobe_instance(kp);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001024 kp->post_handler(kp, regs, flags);
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -08001025 reset_kprobe_instance();
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001026 }
1027 }
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001028}
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001029NOKPROBE_SYMBOL(aggr_post_handler);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001030
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001031static int aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
1032 int trapnr)
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001033{
Christoph Lameterb76834b2010-12-06 11:16:25 -06001034 struct kprobe *cur = __this_cpu_read(kprobe_instance);
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -08001035
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001036 /*
1037 * if we faulted "during" the execution of a user specified
1038 * probe handler, invoke just that probe's fault handler
1039 */
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -08001040 if (cur && cur->fault_handler) {
1041 if (cur->fault_handler(cur, regs, trapnr))
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001042 return 1;
1043 }
1044 return 0;
1045}
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001046NOKPROBE_SYMBOL(aggr_fault_handler);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001047
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001048static int aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -07001049{
Christoph Lameterb76834b2010-12-06 11:16:25 -06001050 struct kprobe *cur = __this_cpu_read(kprobe_instance);
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -08001051 int ret = 0;
1052
1053 if (cur && cur->break_handler) {
1054 if (cur->break_handler(cur, regs))
1055 ret = 1;
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -07001056 }
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -08001057 reset_kprobe_instance();
1058 return ret;
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -07001059}
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001060NOKPROBE_SYMBOL(aggr_break_handler);
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -07001061
Keshavamurthy Anil Sbf8d5c52005-12-12 00:37:34 -08001062/* Walks the list and increments nmissed count for multiprobe case */
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001063void kprobes_inc_nmissed_count(struct kprobe *p)
Keshavamurthy Anil Sbf8d5c52005-12-12 00:37:34 -08001064{
1065 struct kprobe *kp;
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001066 if (!kprobe_aggrprobe(p)) {
Keshavamurthy Anil Sbf8d5c52005-12-12 00:37:34 -08001067 p->nmissed++;
1068 } else {
1069 list_for_each_entry_rcu(kp, &p->list, list)
1070 kp->nmissed++;
1071 }
1072 return;
1073}
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001074NOKPROBE_SYMBOL(kprobes_inc_nmissed_count);
Keshavamurthy Anil Sbf8d5c52005-12-12 00:37:34 -08001075
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001076void recycle_rp_inst(struct kretprobe_instance *ri,
1077 struct hlist_head *head)
Hien Nguyenb94cce92005-06-23 00:09:19 -07001078{
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001079 struct kretprobe *rp = ri->rp;
1080
Hien Nguyenb94cce92005-06-23 00:09:19 -07001081 /* remove rp inst off the rprobe_inst_table */
1082 hlist_del(&ri->hlist);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001083 INIT_HLIST_NODE(&ri->hlist);
1084 if (likely(rp)) {
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001085 raw_spin_lock(&rp->lock);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001086 hlist_add_head(&ri->hlist, &rp->free_instances);
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001087 raw_spin_unlock(&rp->lock);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001088 } else
1089 /* Unregistering */
bibo,mao99219a32006-10-02 02:17:35 -07001090 hlist_add_head(&ri->hlist, head);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001091}
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001092NOKPROBE_SYMBOL(recycle_rp_inst);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001093
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001094void kretprobe_hash_lock(struct task_struct *tsk,
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001095 struct hlist_head **head, unsigned long *flags)
Namhyung Kim635c17c2010-09-15 10:04:30 +09001096__acquires(hlist_lock)
Hien Nguyenb94cce92005-06-23 00:09:19 -07001097{
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001098 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001099 raw_spinlock_t *hlist_lock;
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001100
1101 *head = &kretprobe_inst_table[hash];
1102 hlist_lock = kretprobe_table_lock_ptr(hash);
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001103 raw_spin_lock_irqsave(hlist_lock, *flags);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001104}
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001105NOKPROBE_SYMBOL(kretprobe_hash_lock);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001106
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001107static void kretprobe_table_lock(unsigned long hash,
1108 unsigned long *flags)
Namhyung Kim635c17c2010-09-15 10:04:30 +09001109__acquires(hlist_lock)
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001110{
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001111 raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
1112 raw_spin_lock_irqsave(hlist_lock, *flags);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001113}
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001114NOKPROBE_SYMBOL(kretprobe_table_lock);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001115
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001116void kretprobe_hash_unlock(struct task_struct *tsk,
1117 unsigned long *flags)
Namhyung Kim635c17c2010-09-15 10:04:30 +09001118__releases(hlist_lock)
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001119{
1120 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001121 raw_spinlock_t *hlist_lock;
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001122
1123 hlist_lock = kretprobe_table_lock_ptr(hash);
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001124 raw_spin_unlock_irqrestore(hlist_lock, *flags);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001125}
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001126NOKPROBE_SYMBOL(kretprobe_hash_unlock);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001127
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001128static void kretprobe_table_unlock(unsigned long hash,
1129 unsigned long *flags)
Namhyung Kim635c17c2010-09-15 10:04:30 +09001130__releases(hlist_lock)
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001131{
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001132 raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
1133 raw_spin_unlock_irqrestore(hlist_lock, *flags);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001134}
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001135NOKPROBE_SYMBOL(kretprobe_table_unlock);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001136
Hien Nguyenb94cce92005-06-23 00:09:19 -07001137/*
bibo maoc6fd91f2006-03-26 01:38:20 -08001138 * This function is called from finish_task_switch when task tk becomes dead,
1139 * so that we can recycle any function-return probe instances associated
1140 * with this task. These left over instances represent probed functions
1141 * that have been called but will never return.
Hien Nguyenb94cce92005-06-23 00:09:19 -07001142 */
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001143void kprobe_flush_task(struct task_struct *tk)
Hien Nguyenb94cce92005-06-23 00:09:19 -07001144{
bibo,mao62c27be2006-10-02 02:17:33 -07001145 struct kretprobe_instance *ri;
bibo,mao99219a32006-10-02 02:17:35 -07001146 struct hlist_head *head, empty_rp;
Sasha Levinb67bfe02013-02-27 17:06:00 -08001147 struct hlist_node *tmp;
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001148 unsigned long hash, flags = 0;
Rusty Lynch802eae72005-06-27 15:17:08 -07001149
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001150 if (unlikely(!kprobes_initialized))
1151 /* Early boot. kretprobe_table_locks not yet initialized. */
1152 return;
1153
Ananth N Mavinakayanahallid496aab2012-01-20 14:34:04 -08001154 INIT_HLIST_HEAD(&empty_rp);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001155 hash = hash_ptr(tk, KPROBE_HASH_BITS);
1156 head = &kretprobe_inst_table[hash];
1157 kretprobe_table_lock(hash, &flags);
Sasha Levinb67bfe02013-02-27 17:06:00 -08001158 hlist_for_each_entry_safe(ri, tmp, head, hlist) {
bibo,mao62c27be2006-10-02 02:17:33 -07001159 if (ri->task == tk)
bibo,mao99219a32006-10-02 02:17:35 -07001160 recycle_rp_inst(ri, &empty_rp);
bibo,mao62c27be2006-10-02 02:17:33 -07001161 }
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001162 kretprobe_table_unlock(hash, &flags);
Sasha Levinb67bfe02013-02-27 17:06:00 -08001163 hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
bibo,mao99219a32006-10-02 02:17:35 -07001164 hlist_del(&ri->hlist);
1165 kfree(ri);
1166 }
Hien Nguyenb94cce92005-06-23 00:09:19 -07001167}
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001168NOKPROBE_SYMBOL(kprobe_flush_task);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001169
Hien Nguyenb94cce92005-06-23 00:09:19 -07001170static inline void free_rp_inst(struct kretprobe *rp)
1171{
1172 struct kretprobe_instance *ri;
Sasha Levinb67bfe02013-02-27 17:06:00 -08001173 struct hlist_node *next;
Christoph Hellwig4c4308c2007-05-08 00:34:14 -07001174
Sasha Levinb67bfe02013-02-27 17:06:00 -08001175 hlist_for_each_entry_safe(ri, next, &rp->free_instances, hlist) {
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001176 hlist_del(&ri->hlist);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001177 kfree(ri);
1178 }
1179}
1180
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001181static void cleanup_rp_inst(struct kretprobe *rp)
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001182{
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001183 unsigned long flags, hash;
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001184 struct kretprobe_instance *ri;
Sasha Levinb67bfe02013-02-27 17:06:00 -08001185 struct hlist_node *next;
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001186 struct hlist_head *head;
1187
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001188 /* No race here */
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001189 for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) {
1190 kretprobe_table_lock(hash, &flags);
1191 head = &kretprobe_inst_table[hash];
Sasha Levinb67bfe02013-02-27 17:06:00 -08001192 hlist_for_each_entry_safe(ri, next, head, hlist) {
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001193 if (ri->rp == rp)
1194 ri->rp = NULL;
1195 }
1196 kretprobe_table_unlock(hash, &flags);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001197 }
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001198 free_rp_inst(rp);
1199}
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001200NOKPROBE_SYMBOL(cleanup_rp_inst);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001201
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001202/*
Masami Hiramatsub918e5e2009-04-06 19:00:58 -07001203* Add the new probe to ap->list. Fail if this is the
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -07001204* second jprobe at the address - two jprobes can't coexist
1205*/
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001206static int add_new_kprobe(struct kprobe *ap, struct kprobe *p)
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -07001207{
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001208 BUG_ON(kprobe_gone(ap) || kprobe_gone(p));
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001209
1210 if (p->break_handler || p->post_handler)
Masami Hiramatsu6274de42010-12-03 18:54:09 +09001211 unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001212
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -07001213 if (p->break_handler) {
Masami Hiramatsub918e5e2009-04-06 19:00:58 -07001214 if (ap->break_handler)
mao, bibo36721652006-06-26 00:25:22 -07001215 return -EEXIST;
Masami Hiramatsub918e5e2009-04-06 19:00:58 -07001216 list_add_tail_rcu(&p->list, &ap->list);
1217 ap->break_handler = aggr_break_handler;
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -07001218 } else
Masami Hiramatsub918e5e2009-04-06 19:00:58 -07001219 list_add_rcu(&p->list, &ap->list);
1220 if (p->post_handler && !ap->post_handler)
1221 ap->post_handler = aggr_post_handler;
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001222
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -07001223 return 0;
1224}
1225
1226/*
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001227 * Fill in the required fields of the "manager kprobe". Replace the
1228 * earlier kprobe in the hlist with the manager kprobe
1229 */
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001230static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001231{
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001232 /* Copy p's insn slot to ap */
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -07001233 copy_kprobe(p, ap);
bibo, maoa9ad9652006-07-30 03:03:26 -07001234 flush_insn_slot(ap);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001235 ap->addr = p->addr;
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001236 ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001237 ap->pre_handler = aggr_pre_handler;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001238 ap->fault_handler = aggr_fault_handler;
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001239 /* We don't care the kprobe which has gone. */
1240 if (p->post_handler && !kprobe_gone(p))
mao, bibo36721652006-06-26 00:25:22 -07001241 ap->post_handler = aggr_post_handler;
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001242 if (p->break_handler && !kprobe_gone(p))
mao, bibo36721652006-06-26 00:25:22 -07001243 ap->break_handler = aggr_break_handler;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001244
1245 INIT_LIST_HEAD(&ap->list);
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001246 INIT_HLIST_NODE(&ap->hlist);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001247
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001248 list_add_rcu(&p->list, &ap->list);
Keshavamurthy Anil Sadad0f32005-12-12 00:37:12 -08001249 hlist_replace_rcu(&p->hlist, &ap->hlist);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001250}
1251
1252/*
1253 * This is the second or subsequent kprobe at the address - handle
1254 * the intricacies
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001255 */
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001256static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p)
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001257{
1258 int ret = 0;
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001259 struct kprobe *ap = orig_p;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001260
Masami Hiramatsu25764282012-06-05 19:28:26 +09001261 /* For preparing optimization, jump_label_text_reserved() is called */
1262 jump_label_lock();
1263 /*
1264 * Get online CPUs to avoid text_mutex deadlock.with stop machine,
1265 * which is invoked by unoptimize_kprobe() in add_new_kprobe()
1266 */
1267 get_online_cpus();
1268 mutex_lock(&text_mutex);
1269
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001270 if (!kprobe_aggrprobe(orig_p)) {
1271 /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */
1272 ap = alloc_aggr_kprobe(orig_p);
Masami Hiramatsu25764282012-06-05 19:28:26 +09001273 if (!ap) {
1274 ret = -ENOMEM;
1275 goto out;
1276 }
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001277 init_aggr_kprobe(ap, orig_p);
Masami Hiramatsu6274de42010-12-03 18:54:09 +09001278 } else if (kprobe_unused(ap))
Masami Hiramatsu0490cd12010-12-03 18:54:16 +09001279 /* This probe is going to die. Rescue it */
1280 reuse_unused_kprobe(ap);
Masami Hiramatsub918e5e2009-04-06 19:00:58 -07001281
1282 if (kprobe_gone(ap)) {
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001283 /*
1284 * Attempting to insert new probe at the same location that
1285 * had a probe in the module vaddr area which already
1286 * freed. So, the instruction slot has already been
1287 * released. We need a new slot for the new probe.
1288 */
Masami Hiramatsub918e5e2009-04-06 19:00:58 -07001289 ret = arch_prepare_kprobe(ap);
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001290 if (ret)
Masami Hiramatsub918e5e2009-04-06 19:00:58 -07001291 /*
1292 * Even if fail to allocate new slot, don't need to
1293 * free aggr_probe. It will be used next time, or
1294 * freed by unregister_kprobe.
1295 */
Masami Hiramatsu25764282012-06-05 19:28:26 +09001296 goto out;
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001297
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001298 /* Prepare optimized instructions if possible. */
1299 prepare_optimized_kprobe(ap);
1300
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001301 /*
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001302 * Clear gone flag to prevent allocating new slot again, and
1303 * set disabled flag because it is not armed yet.
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001304 */
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001305 ap->flags = (ap->flags & ~KPROBE_FLAG_GONE)
1306 | KPROBE_FLAG_DISABLED;
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001307 }
Masami Hiramatsub918e5e2009-04-06 19:00:58 -07001308
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001309 /* Copy ap's insn slot to p */
Masami Hiramatsub918e5e2009-04-06 19:00:58 -07001310 copy_kprobe(ap, p);
Masami Hiramatsu25764282012-06-05 19:28:26 +09001311 ret = add_new_kprobe(ap, p);
1312
1313out:
1314 mutex_unlock(&text_mutex);
1315 put_online_cpus();
1316 jump_label_unlock();
1317
1318 if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) {
1319 ap->flags &= ~KPROBE_FLAG_DISABLED;
1320 if (!kprobes_all_disarmed)
1321 /* Arm the breakpoint again. */
1322 arm_kprobe(ap);
1323 }
1324 return ret;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001325}
1326
Masami Hiramatsube8f2742014-04-17 17:16:58 +09001327bool __weak arch_within_kprobe_blacklist(unsigned long addr)
1328{
1329 /* The __kprobes marked functions and entry code must not be probed */
1330 return addr >= (unsigned long)__kprobes_text_start &&
1331 addr < (unsigned long)__kprobes_text_end;
1332}
1333
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001334static bool within_kprobe_blacklist(unsigned long addr)
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -07001335{
Masami Hiramatsu376e2422014-04-17 17:17:05 +09001336 struct kprobe_blacklist_entry *ent;
Srinivasa Ds3d8d9962008-04-28 02:14:26 -07001337
Masami Hiramatsube8f2742014-04-17 17:16:58 +09001338 if (arch_within_kprobe_blacklist(addr))
Masami Hiramatsu376e2422014-04-17 17:17:05 +09001339 return true;
Srinivasa Ds3d8d9962008-04-28 02:14:26 -07001340 /*
1341 * If there exists a kprobe_blacklist, verify and
1342 * fail any probe registration in the prohibited area
1343 */
Masami Hiramatsu376e2422014-04-17 17:17:05 +09001344 list_for_each_entry(ent, &kprobe_blacklist, list) {
1345 if (addr >= ent->start_addr && addr < ent->end_addr)
1346 return true;
Srinivasa Ds3d8d9962008-04-28 02:14:26 -07001347 }
Masami Hiramatsu376e2422014-04-17 17:17:05 +09001348
1349 return false;
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -07001350}
1351
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001352/*
1353 * If we have a symbol_name argument, look it up and add the offset field
1354 * to it. This way, we can specify a relative address to a symbol.
Masami Hiramatsubc81d482011-06-27 16:26:50 +09001355 * This returns encoded errors if it fails to look up symbol or invalid
1356 * combination of parameters.
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001357 */
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001358static kprobe_opcode_t *kprobe_addr(struct kprobe *p)
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001359{
1360 kprobe_opcode_t *addr = p->addr;
Masami Hiramatsubc81d482011-06-27 16:26:50 +09001361
1362 if ((p->symbol_name && p->addr) ||
1363 (!p->symbol_name && !p->addr))
1364 goto invalid;
1365
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001366 if (p->symbol_name) {
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001367 kprobe_lookup_name(p->symbol_name, addr);
Masami Hiramatsubc81d482011-06-27 16:26:50 +09001368 if (!addr)
1369 return ERR_PTR(-ENOENT);
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001370 }
1371
Masami Hiramatsubc81d482011-06-27 16:26:50 +09001372 addr = (kprobe_opcode_t *)(((char *)addr) + p->offset);
1373 if (addr)
1374 return addr;
1375
1376invalid:
1377 return ERR_PTR(-EINVAL);
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001378}
1379
Ananth N Mavinakayanahalli1f0ab402009-09-15 10:43:07 +05301380/* Check passed kprobe is valid and return kprobe in kprobe_table. */
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001381static struct kprobe *__get_valid_kprobe(struct kprobe *p)
Ananth N Mavinakayanahalli1f0ab402009-09-15 10:43:07 +05301382{
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001383 struct kprobe *ap, *list_p;
Ananth N Mavinakayanahalli1f0ab402009-09-15 10:43:07 +05301384
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001385 ap = get_kprobe(p->addr);
1386 if (unlikely(!ap))
Ananth N Mavinakayanahalli1f0ab402009-09-15 10:43:07 +05301387 return NULL;
1388
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001389 if (p != ap) {
1390 list_for_each_entry_rcu(list_p, &ap->list, list)
Ananth N Mavinakayanahalli1f0ab402009-09-15 10:43:07 +05301391 if (list_p == p)
1392 /* kprobe p is a valid probe */
1393 goto valid;
1394 return NULL;
1395 }
1396valid:
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001397 return ap;
Ananth N Mavinakayanahalli1f0ab402009-09-15 10:43:07 +05301398}
1399
1400/* Return error if the kprobe is being re-registered */
1401static inline int check_kprobe_rereg(struct kprobe *p)
1402{
1403 int ret = 0;
Ananth N Mavinakayanahalli1f0ab402009-09-15 10:43:07 +05301404
1405 mutex_lock(&kprobe_mutex);
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001406 if (__get_valid_kprobe(p))
Ananth N Mavinakayanahalli1f0ab402009-09-15 10:43:07 +05301407 ret = -EINVAL;
1408 mutex_unlock(&kprobe_mutex);
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001409
Ananth N Mavinakayanahalli1f0ab402009-09-15 10:43:07 +05301410 return ret;
1411}
1412
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001413static int check_kprobe_address_safe(struct kprobe *p,
1414 struct module **probed_mod)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001415{
1416 int ret = 0;
Masami Hiramatsuae6aa162012-06-05 19:28:32 +09001417 unsigned long ftrace_addr;
1418
1419 /*
1420 * If the address is located on a ftrace nop, set the
1421 * breakpoint to the following instruction.
1422 */
1423 ftrace_addr = ftrace_location((unsigned long)p->addr);
1424 if (ftrace_addr) {
Masami Hiramatsue7dbfe32012-09-28 17:15:20 +09001425#ifdef CONFIG_KPROBES_ON_FTRACE
Masami Hiramatsuae6aa162012-06-05 19:28:32 +09001426 /* Given address is not on the instruction boundary */
1427 if ((unsigned long)p->addr != ftrace_addr)
1428 return -EILSEQ;
Masami Hiramatsuae6aa162012-06-05 19:28:32 +09001429 p->flags |= KPROBE_FLAG_FTRACE;
Masami Hiramatsue7dbfe32012-09-28 17:15:20 +09001430#else /* !CONFIG_KPROBES_ON_FTRACE */
Masami Hiramatsuae6aa162012-06-05 19:28:32 +09001431 return -EINVAL;
1432#endif
1433 }
Masami Hiramatsuf7fa6ef02012-06-05 19:28:20 +09001434
1435 jump_label_lock();
1436 preempt_disable();
1437
1438 /* Ensure it is not in reserved area nor out of text */
1439 if (!kernel_text_address((unsigned long) p->addr) ||
Masami Hiramatsu376e2422014-04-17 17:17:05 +09001440 within_kprobe_blacklist((unsigned long) p->addr) ||
Masami Hiramatsuf7fa6ef02012-06-05 19:28:20 +09001441 jump_label_text_reserved(p->addr, p->addr)) {
1442 ret = -EINVAL;
1443 goto out;
1444 }
1445
1446 /* Check if are we probing a module */
1447 *probed_mod = __module_text_address((unsigned long) p->addr);
1448 if (*probed_mod) {
1449 /*
1450 * We must hold a refcount of the probed module while updating
1451 * its code to prohibit unexpected unloading.
1452 */
1453 if (unlikely(!try_module_get(*probed_mod))) {
1454 ret = -ENOENT;
1455 goto out;
1456 }
1457
1458 /*
1459 * If the module freed .init.text, we couldn't insert
1460 * kprobes in there.
1461 */
1462 if (within_module_init((unsigned long)p->addr, *probed_mod) &&
1463 (*probed_mod)->state != MODULE_STATE_COMING) {
1464 module_put(*probed_mod);
1465 *probed_mod = NULL;
1466 ret = -ENOENT;
1467 }
1468 }
1469out:
1470 preempt_enable();
1471 jump_label_unlock();
1472
1473 return ret;
1474}
1475
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001476int register_kprobe(struct kprobe *p)
Masami Hiramatsuf7fa6ef02012-06-05 19:28:20 +09001477{
1478 int ret;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001479 struct kprobe *old_p;
Keshavamurthy Anil Sdf019b12006-01-11 12:17:41 -08001480 struct module *probed_mod;
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001481 kprobe_opcode_t *addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001482
Masami Hiramatsuf7fa6ef02012-06-05 19:28:20 +09001483 /* Adjust probe address from symbol */
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001484 addr = kprobe_addr(p);
Masami Hiramatsubc81d482011-06-27 16:26:50 +09001485 if (IS_ERR(addr))
1486 return PTR_ERR(addr);
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001487 p->addr = addr;
Ananth N Mavinakayanahalli3a872d82006-10-02 02:17:30 -07001488
Ananth N Mavinakayanahalli1f0ab402009-09-15 10:43:07 +05301489 ret = check_kprobe_rereg(p);
1490 if (ret)
1491 return ret;
1492
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001493 /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
1494 p->flags &= KPROBE_FLAG_DISABLED;
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -08001495 p->nmissed = 0;
Masami Hiramatsu98616682008-04-28 02:14:28 -07001496 INIT_LIST_HEAD(&p->list);
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001497
Masami Hiramatsuf7fa6ef02012-06-05 19:28:20 +09001498 ret = check_kprobe_address_safe(p, &probed_mod);
1499 if (ret)
1500 return ret;
1501
1502 mutex_lock(&kprobe_mutex);
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001503
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001504 old_p = get_kprobe(p->addr);
1505 if (old_p) {
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001506 /* Since this may unoptimize old_p, locking text_mutex. */
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001507 ret = register_aggr_kprobe(old_p, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001508 goto out;
1509 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001510
Masami Hiramatsu25764282012-06-05 19:28:26 +09001511 mutex_lock(&text_mutex); /* Avoiding text modification */
Masami Hiramatsuae6aa162012-06-05 19:28:32 +09001512 ret = prepare_kprobe(p);
Masami Hiramatsu25764282012-06-05 19:28:26 +09001513 mutex_unlock(&text_mutex);
Christoph Hellwig6f716ac2007-05-08 00:34:13 -07001514 if (ret)
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001515 goto out;
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -08001516
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001517 INIT_HLIST_NODE(&p->hlist);
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -08001518 hlist_add_head_rcu(&p->hlist,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001519 &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
1520
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001521 if (!kprobes_all_disarmed && !kprobe_disabled(p))
Masami Hiramatsu25764282012-06-05 19:28:26 +09001522 arm_kprobe(p);
Christoph Hellwig74a0b572007-10-16 01:24:07 -07001523
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001524 /* Try to optimize kprobe */
1525 try_to_optimize_kprobe(p);
1526
Linus Torvalds1da177e2005-04-16 15:20:36 -07001527out:
Ingo Molnar7a7d1cf2006-03-23 03:00:35 -08001528 mutex_unlock(&kprobe_mutex);
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -08001529
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001530 if (probed_mod)
Keshavamurthy Anil Sdf019b12006-01-11 12:17:41 -08001531 module_put(probed_mod);
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001532
Linus Torvalds1da177e2005-04-16 15:20:36 -07001533 return ret;
1534}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001535EXPORT_SYMBOL_GPL(register_kprobe);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001536
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001537/* Check if all probes on the aggrprobe are disabled */
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001538static int aggr_kprobe_disabled(struct kprobe *ap)
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001539{
1540 struct kprobe *kp;
1541
1542 list_for_each_entry_rcu(kp, &ap->list, list)
1543 if (!kprobe_disabled(kp))
1544 /*
1545 * There is an active probe on the list.
1546 * We can't disable this ap.
1547 */
1548 return 0;
1549
1550 return 1;
1551}
1552
1553/* Disable one kprobe: Make sure called under kprobe_mutex is locked */
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001554static struct kprobe *__disable_kprobe(struct kprobe *p)
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001555{
1556 struct kprobe *orig_p;
1557
1558 /* Get an original kprobe for return */
1559 orig_p = __get_valid_kprobe(p);
1560 if (unlikely(orig_p == NULL))
1561 return NULL;
1562
1563 if (!kprobe_disabled(p)) {
1564 /* Disable probe if it is a child probe */
1565 if (p != orig_p)
1566 p->flags |= KPROBE_FLAG_DISABLED;
1567
1568 /* Try to disarm and disable this/parent probe */
1569 if (p == orig_p || aggr_kprobe_disabled(orig_p)) {
Masami Hiramatsuae6aa162012-06-05 19:28:32 +09001570 disarm_kprobe(orig_p, true);
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001571 orig_p->flags |= KPROBE_FLAG_DISABLED;
1572 }
1573 }
1574
1575 return orig_p;
1576}
1577
Masami Hiramatsu98616682008-04-28 02:14:28 -07001578/*
1579 * Unregister a kprobe without a scheduler synchronization.
1580 */
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001581static int __unregister_kprobe_top(struct kprobe *p)
Keshavamurthy Anil Sdf019b12006-01-11 12:17:41 -08001582{
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001583 struct kprobe *ap, *list_p;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001584
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001585 /* Disable kprobe. This will disarm it if needed. */
1586 ap = __disable_kprobe(p);
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001587 if (ap == NULL)
Masami Hiramatsu98616682008-04-28 02:14:28 -07001588 return -EINVAL;
1589
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001590 if (ap == p)
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001591 /*
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001592 * This probe is an independent(and non-optimized) kprobe
1593 * (not an aggrprobe). Remove from the hash list.
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001594 */
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001595 goto disarmed;
1596
1597 /* Following process expects this probe is an aggrprobe */
1598 WARN_ON(!kprobe_aggrprobe(ap));
1599
Masami Hiramatsu6274de42010-12-03 18:54:09 +09001600 if (list_is_singular(&ap->list) && kprobe_disarmed(ap))
1601 /*
1602 * !disarmed could be happen if the probe is under delayed
1603 * unoptimizing.
1604 */
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001605 goto disarmed;
1606 else {
1607 /* If disabling probe has special handlers, update aggrprobe */
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001608 if (p->break_handler && !kprobe_gone(p))
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001609 ap->break_handler = NULL;
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001610 if (p->post_handler && !kprobe_gone(p)) {
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001611 list_for_each_entry_rcu(list_p, &ap->list, list) {
Masami Hiramatsu98616682008-04-28 02:14:28 -07001612 if ((list_p != p) && (list_p->post_handler))
1613 goto noclean;
1614 }
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001615 ap->post_handler = NULL;
Masami Hiramatsu98616682008-04-28 02:14:28 -07001616 }
1617noclean:
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001618 /*
1619 * Remove from the aggrprobe: this path will do nothing in
1620 * __unregister_kprobe_bottom().
1621 */
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -08001622 list_del_rcu(&p->list);
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001623 if (!kprobe_disabled(ap) && !kprobes_all_disarmed)
1624 /*
1625 * Try to optimize this probe again, because post
1626 * handler may have been changed.
1627 */
1628 optimize_kprobe(ap);
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -08001629 }
Masami Hiramatsu98616682008-04-28 02:14:28 -07001630 return 0;
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001631
1632disarmed:
Masami Hiramatsu6274de42010-12-03 18:54:09 +09001633 BUG_ON(!kprobe_disarmed(ap));
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001634 hlist_del_rcu(&ap->hlist);
1635 return 0;
Masami Hiramatsu98616682008-04-28 02:14:28 -07001636}
Mao, Bibob3e55c72005-12-12 00:37:00 -08001637
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001638static void __unregister_kprobe_bottom(struct kprobe *p)
Masami Hiramatsu98616682008-04-28 02:14:28 -07001639{
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001640 struct kprobe *ap;
Mao, Bibob3e55c72005-12-12 00:37:00 -08001641
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001642 if (list_empty(&p->list))
Masami Hiramatsu6274de42010-12-03 18:54:09 +09001643 /* This is an independent kprobe */
Ananth N Mavinakayanahalli0498b632006-01-09 20:52:46 -08001644 arch_remove_kprobe(p);
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001645 else if (list_is_singular(&p->list)) {
Masami Hiramatsu6274de42010-12-03 18:54:09 +09001646 /* This is the last child of an aggrprobe */
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001647 ap = list_entry(p->list.next, struct kprobe, list);
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001648 list_del(&p->list);
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001649 free_aggr_kprobe(ap);
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -08001650 }
Masami Hiramatsu6274de42010-12-03 18:54:09 +09001651 /* Otherwise, do nothing. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001652}
1653
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001654int register_kprobes(struct kprobe **kps, int num)
Masami Hiramatsu98616682008-04-28 02:14:28 -07001655{
1656 int i, ret = 0;
1657
1658 if (num <= 0)
1659 return -EINVAL;
1660 for (i = 0; i < num; i++) {
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -08001661 ret = register_kprobe(kps[i]);
Masami Hiramatsu67dddaa2008-06-12 15:21:35 -07001662 if (ret < 0) {
1663 if (i > 0)
1664 unregister_kprobes(kps, i);
Masami Hiramatsu98616682008-04-28 02:14:28 -07001665 break;
1666 }
1667 }
1668 return ret;
1669}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001670EXPORT_SYMBOL_GPL(register_kprobes);
Masami Hiramatsu98616682008-04-28 02:14:28 -07001671
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001672void unregister_kprobe(struct kprobe *p)
Masami Hiramatsu98616682008-04-28 02:14:28 -07001673{
1674 unregister_kprobes(&p, 1);
1675}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001676EXPORT_SYMBOL_GPL(unregister_kprobe);
Masami Hiramatsu98616682008-04-28 02:14:28 -07001677
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001678void unregister_kprobes(struct kprobe **kps, int num)
Masami Hiramatsu98616682008-04-28 02:14:28 -07001679{
1680 int i;
1681
1682 if (num <= 0)
1683 return;
1684 mutex_lock(&kprobe_mutex);
1685 for (i = 0; i < num; i++)
1686 if (__unregister_kprobe_top(kps[i]) < 0)
1687 kps[i]->addr = NULL;
1688 mutex_unlock(&kprobe_mutex);
1689
1690 synchronize_sched();
1691 for (i = 0; i < num; i++)
1692 if (kps[i]->addr)
1693 __unregister_kprobe_bottom(kps[i]);
1694}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001695EXPORT_SYMBOL_GPL(unregister_kprobes);
Masami Hiramatsu98616682008-04-28 02:14:28 -07001696
Linus Torvalds1da177e2005-04-16 15:20:36 -07001697static struct notifier_block kprobe_exceptions_nb = {
1698 .notifier_call = kprobe_exceptions_notify,
Anil S Keshavamurthy3d5631e2006-06-26 00:25:28 -07001699 .priority = 0x7fffffff /* we need to be notified first */
1700};
1701
Michael Ellerman3d7e3382007-07-19 01:48:11 -07001702unsigned long __weak arch_deref_entry_point(void *entry)
1703{
1704 return (unsigned long)entry;
1705}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001706
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001707int register_jprobes(struct jprobe **jps, int num)
Masami Hiramatsu26b31c12008-04-28 02:14:29 -07001708{
1709 struct jprobe *jp;
1710 int ret = 0, i;
1711
1712 if (num <= 0)
1713 return -EINVAL;
1714 for (i = 0; i < num; i++) {
Namhyung Kim05662bd2010-09-15 10:04:27 +09001715 unsigned long addr, offset;
Masami Hiramatsu26b31c12008-04-28 02:14:29 -07001716 jp = jps[i];
1717 addr = arch_deref_entry_point(jp->entry);
1718
Namhyung Kim05662bd2010-09-15 10:04:27 +09001719 /* Verify probepoint is a function entry point */
1720 if (kallsyms_lookup_size_offset(addr, NULL, &offset) &&
1721 offset == 0) {
1722 jp->kp.pre_handler = setjmp_pre_handler;
1723 jp->kp.break_handler = longjmp_break_handler;
1724 ret = register_kprobe(&jp->kp);
1725 } else
1726 ret = -EINVAL;
Namhyung Kimedbaadb2010-09-15 10:04:26 +09001727
Masami Hiramatsu67dddaa2008-06-12 15:21:35 -07001728 if (ret < 0) {
1729 if (i > 0)
1730 unregister_jprobes(jps, i);
Masami Hiramatsu26b31c12008-04-28 02:14:29 -07001731 break;
1732 }
1733 }
1734 return ret;
1735}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001736EXPORT_SYMBOL_GPL(register_jprobes);
Masami Hiramatsu26b31c12008-04-28 02:14:29 -07001737
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001738int register_jprobe(struct jprobe *jp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001739{
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -08001740 return register_jprobes(&jp, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001741}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001742EXPORT_SYMBOL_GPL(register_jprobe);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001743
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001744void unregister_jprobe(struct jprobe *jp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001745{
Masami Hiramatsu26b31c12008-04-28 02:14:29 -07001746 unregister_jprobes(&jp, 1);
1747}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001748EXPORT_SYMBOL_GPL(unregister_jprobe);
Masami Hiramatsu26b31c12008-04-28 02:14:29 -07001749
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001750void unregister_jprobes(struct jprobe **jps, int num)
Masami Hiramatsu26b31c12008-04-28 02:14:29 -07001751{
1752 int i;
1753
1754 if (num <= 0)
1755 return;
1756 mutex_lock(&kprobe_mutex);
1757 for (i = 0; i < num; i++)
1758 if (__unregister_kprobe_top(&jps[i]->kp) < 0)
1759 jps[i]->kp.addr = NULL;
1760 mutex_unlock(&kprobe_mutex);
1761
1762 synchronize_sched();
1763 for (i = 0; i < num; i++) {
1764 if (jps[i]->kp.addr)
1765 __unregister_kprobe_bottom(&jps[i]->kp);
1766 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001767}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001768EXPORT_SYMBOL_GPL(unregister_jprobes);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001769
Ananth N Mavinakayanahalli9edddaa2008-03-04 14:28:37 -08001770#ifdef CONFIG_KRETPROBES
Adrian Bunke65cefe2006-02-03 03:03:42 -08001771/*
1772 * This kprobe pre_handler is registered with every kretprobe. When probe
1773 * hits it will set up the return probe.
1774 */
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001775static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
Adrian Bunke65cefe2006-02-03 03:03:42 -08001776{
1777 struct kretprobe *rp = container_of(p, struct kretprobe, kp);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001778 unsigned long hash, flags = 0;
1779 struct kretprobe_instance *ri;
Adrian Bunke65cefe2006-02-03 03:03:42 -08001780
1781 /*TODO: consider to only swap the RA after the last pre_handler fired */
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001782 hash = hash_ptr(current, KPROBE_HASH_BITS);
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001783 raw_spin_lock_irqsave(&rp->lock, flags);
Christoph Hellwig4c4308c2007-05-08 00:34:14 -07001784 if (!hlist_empty(&rp->free_instances)) {
Christoph Hellwig4c4308c2007-05-08 00:34:14 -07001785 ri = hlist_entry(rp->free_instances.first,
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001786 struct kretprobe_instance, hlist);
1787 hlist_del(&ri->hlist);
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001788 raw_spin_unlock_irqrestore(&rp->lock, flags);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001789
Christoph Hellwig4c4308c2007-05-08 00:34:14 -07001790 ri->rp = rp;
1791 ri->task = current;
Abhishek Sagarf47cd9b2008-02-06 01:38:22 -08001792
Jiang Liu55ca6142012-02-03 15:37:16 -08001793 if (rp->entry_handler && rp->entry_handler(ri, regs)) {
1794 raw_spin_lock_irqsave(&rp->lock, flags);
1795 hlist_add_head(&ri->hlist, &rp->free_instances);
1796 raw_spin_unlock_irqrestore(&rp->lock, flags);
Abhishek Sagarf47cd9b2008-02-06 01:38:22 -08001797 return 0;
Jiang Liu55ca6142012-02-03 15:37:16 -08001798 }
Abhishek Sagarf47cd9b2008-02-06 01:38:22 -08001799
Christoph Hellwig4c4308c2007-05-08 00:34:14 -07001800 arch_prepare_kretprobe(ri, regs);
1801
1802 /* XXX(hch): why is there no hlist_move_head? */
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001803 INIT_HLIST_NODE(&ri->hlist);
1804 kretprobe_table_lock(hash, &flags);
1805 hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]);
1806 kretprobe_table_unlock(hash, &flags);
1807 } else {
Christoph Hellwig4c4308c2007-05-08 00:34:14 -07001808 rp->nmissed++;
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001809 raw_spin_unlock_irqrestore(&rp->lock, flags);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001810 }
Adrian Bunke65cefe2006-02-03 03:03:42 -08001811 return 0;
1812}
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001813NOKPROBE_SYMBOL(pre_handler_kretprobe);
Adrian Bunke65cefe2006-02-03 03:03:42 -08001814
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001815int register_kretprobe(struct kretprobe *rp)
Hien Nguyenb94cce92005-06-23 00:09:19 -07001816{
1817 int ret = 0;
1818 struct kretprobe_instance *inst;
1819 int i;
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001820 void *addr;
Masami Hiramatsuf438d912007-10-16 01:27:49 -07001821
1822 if (kretprobe_blacklist_size) {
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001823 addr = kprobe_addr(&rp->kp);
Masami Hiramatsubc81d482011-06-27 16:26:50 +09001824 if (IS_ERR(addr))
1825 return PTR_ERR(addr);
Masami Hiramatsuf438d912007-10-16 01:27:49 -07001826
1827 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
1828 if (kretprobe_blacklist[i].addr == addr)
1829 return -EINVAL;
1830 }
1831 }
Hien Nguyenb94cce92005-06-23 00:09:19 -07001832
1833 rp->kp.pre_handler = pre_handler_kretprobe;
Ananth N Mavinakayanahalli7522a842006-04-20 02:43:11 -07001834 rp->kp.post_handler = NULL;
1835 rp->kp.fault_handler = NULL;
1836 rp->kp.break_handler = NULL;
Hien Nguyenb94cce92005-06-23 00:09:19 -07001837
1838 /* Pre-allocate memory for max kretprobe instances */
1839 if (rp->maxactive <= 0) {
1840#ifdef CONFIG_PREEMPT
Heiko Carstensc2ef6662009-12-21 13:02:24 +01001841 rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());
Hien Nguyenb94cce92005-06-23 00:09:19 -07001842#else
Ananth N Mavinakayanahalli4dae5602009-10-30 19:23:10 +05301843 rp->maxactive = num_possible_cpus();
Hien Nguyenb94cce92005-06-23 00:09:19 -07001844#endif
1845 }
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001846 raw_spin_lock_init(&rp->lock);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001847 INIT_HLIST_HEAD(&rp->free_instances);
1848 for (i = 0; i < rp->maxactive; i++) {
Abhishek Sagarf47cd9b2008-02-06 01:38:22 -08001849 inst = kmalloc(sizeof(struct kretprobe_instance) +
1850 rp->data_size, GFP_KERNEL);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001851 if (inst == NULL) {
1852 free_rp_inst(rp);
1853 return -ENOMEM;
1854 }
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001855 INIT_HLIST_NODE(&inst->hlist);
1856 hlist_add_head(&inst->hlist, &rp->free_instances);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001857 }
1858
1859 rp->nmissed = 0;
1860 /* Establish function entry probe point */
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -08001861 ret = register_kprobe(&rp->kp);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001862 if (ret != 0)
Hien Nguyenb94cce92005-06-23 00:09:19 -07001863 free_rp_inst(rp);
1864 return ret;
1865}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001866EXPORT_SYMBOL_GPL(register_kretprobe);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001867
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001868int register_kretprobes(struct kretprobe **rps, int num)
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001869{
1870 int ret = 0, i;
1871
1872 if (num <= 0)
1873 return -EINVAL;
1874 for (i = 0; i < num; i++) {
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -08001875 ret = register_kretprobe(rps[i]);
Masami Hiramatsu67dddaa2008-06-12 15:21:35 -07001876 if (ret < 0) {
1877 if (i > 0)
1878 unregister_kretprobes(rps, i);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001879 break;
1880 }
1881 }
1882 return ret;
1883}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001884EXPORT_SYMBOL_GPL(register_kretprobes);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001885
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001886void unregister_kretprobe(struct kretprobe *rp)
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001887{
1888 unregister_kretprobes(&rp, 1);
1889}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001890EXPORT_SYMBOL_GPL(unregister_kretprobe);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001891
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001892void unregister_kretprobes(struct kretprobe **rps, int num)
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001893{
1894 int i;
1895
1896 if (num <= 0)
1897 return;
1898 mutex_lock(&kprobe_mutex);
1899 for (i = 0; i < num; i++)
1900 if (__unregister_kprobe_top(&rps[i]->kp) < 0)
1901 rps[i]->kp.addr = NULL;
1902 mutex_unlock(&kprobe_mutex);
1903
1904 synchronize_sched();
1905 for (i = 0; i < num; i++) {
1906 if (rps[i]->kp.addr) {
1907 __unregister_kprobe_bottom(&rps[i]->kp);
1908 cleanup_rp_inst(rps[i]);
1909 }
1910 }
1911}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001912EXPORT_SYMBOL_GPL(unregister_kretprobes);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001913
Ananth N Mavinakayanahalli9edddaa2008-03-04 14:28:37 -08001914#else /* CONFIG_KRETPROBES */
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001915int register_kretprobe(struct kretprobe *rp)
Hien Nguyenb94cce92005-06-23 00:09:19 -07001916{
1917 return -ENOSYS;
1918}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001919EXPORT_SYMBOL_GPL(register_kretprobe);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001920
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001921int register_kretprobes(struct kretprobe **rps, int num)
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001922{
1923 return -ENOSYS;
1924}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001925EXPORT_SYMBOL_GPL(register_kretprobes);
1926
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001927void unregister_kretprobe(struct kretprobe *rp)
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001928{
1929}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001930EXPORT_SYMBOL_GPL(unregister_kretprobe);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001931
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001932void unregister_kretprobes(struct kretprobe **rps, int num)
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001933{
1934}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001935EXPORT_SYMBOL_GPL(unregister_kretprobes);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001936
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001937static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
Srinivasa Ds346fd592007-02-20 13:57:54 -08001938{
1939 return 0;
1940}
Masami Hiramatsu820aede2014-04-17 17:18:21 +09001941NOKPROBE_SYMBOL(pre_handler_kretprobe);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001942
Ananth N Mavinakayanahalli9edddaa2008-03-04 14:28:37 -08001943#endif /* CONFIG_KRETPROBES */
Hien Nguyenb94cce92005-06-23 00:09:19 -07001944
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001945/* Set the kprobe gone and remove its instruction buffer. */
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001946static void kill_kprobe(struct kprobe *p)
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001947{
1948 struct kprobe *kp;
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001949
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001950 p->flags |= KPROBE_FLAG_GONE;
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001951 if (kprobe_aggrprobe(p)) {
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001952 /*
1953 * If this is an aggr_kprobe, we have to list all the
1954 * chained probes and mark them GONE.
1955 */
1956 list_for_each_entry_rcu(kp, &p->list, list)
1957 kp->flags |= KPROBE_FLAG_GONE;
1958 p->post_handler = NULL;
1959 p->break_handler = NULL;
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001960 kill_optimized_kprobe(p);
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001961 }
1962 /*
1963 * Here, we can remove insn_slot safely, because no thread calls
1964 * the original probed function (which will be freed soon) any more.
1965 */
1966 arch_remove_kprobe(p);
1967}
1968
Masami Hiramatsuc0614822010-04-27 18:33:12 -04001969/* Disable one kprobe */
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001970int disable_kprobe(struct kprobe *kp)
Masami Hiramatsuc0614822010-04-27 18:33:12 -04001971{
1972 int ret = 0;
Masami Hiramatsuc0614822010-04-27 18:33:12 -04001973
1974 mutex_lock(&kprobe_mutex);
1975
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001976 /* Disable this kprobe */
1977 if (__disable_kprobe(kp) == NULL)
Masami Hiramatsuc0614822010-04-27 18:33:12 -04001978 ret = -EINVAL;
Masami Hiramatsuc0614822010-04-27 18:33:12 -04001979
Masami Hiramatsuc0614822010-04-27 18:33:12 -04001980 mutex_unlock(&kprobe_mutex);
1981 return ret;
1982}
1983EXPORT_SYMBOL_GPL(disable_kprobe);
1984
1985/* Enable one kprobe */
Masami Hiramatsu55479f62014-04-17 17:17:54 +09001986int enable_kprobe(struct kprobe *kp)
Masami Hiramatsuc0614822010-04-27 18:33:12 -04001987{
1988 int ret = 0;
1989 struct kprobe *p;
1990
1991 mutex_lock(&kprobe_mutex);
1992
1993 /* Check whether specified probe is valid. */
1994 p = __get_valid_kprobe(kp);
1995 if (unlikely(p == NULL)) {
1996 ret = -EINVAL;
1997 goto out;
1998 }
1999
2000 if (kprobe_gone(kp)) {
2001 /* This kprobe has gone, we couldn't enable it. */
2002 ret = -EINVAL;
2003 goto out;
2004 }
2005
2006 if (p != kp)
2007 kp->flags &= ~KPROBE_FLAG_DISABLED;
2008
2009 if (!kprobes_all_disarmed && kprobe_disabled(p)) {
2010 p->flags &= ~KPROBE_FLAG_DISABLED;
2011 arm_kprobe(p);
2012 }
2013out:
2014 mutex_unlock(&kprobe_mutex);
2015 return ret;
2016}
2017EXPORT_SYMBOL_GPL(enable_kprobe);
2018
Masami Hiramatsu820aede2014-04-17 17:18:21 +09002019void dump_kprobe(struct kprobe *kp)
Frederic Weisbecker24851d22009-08-26 23:38:30 +02002020{
2021 printk(KERN_WARNING "Dumping kprobe:\n");
2022 printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n",
2023 kp->symbol_name, kp->addr, kp->offset);
2024}
Masami Hiramatsu820aede2014-04-17 17:18:21 +09002025NOKPROBE_SYMBOL(dump_kprobe);
Frederic Weisbecker24851d22009-08-26 23:38:30 +02002026
Masami Hiramatsu376e2422014-04-17 17:17:05 +09002027/*
2028 * Lookup and populate the kprobe_blacklist.
2029 *
2030 * Unlike the kretprobe blacklist, we'll need to determine
2031 * the range of addresses that belong to the said functions,
2032 * since a kprobe need not necessarily be at the beginning
2033 * of a function.
2034 */
2035static int __init populate_kprobe_blacklist(unsigned long *start,
2036 unsigned long *end)
2037{
2038 unsigned long *iter;
2039 struct kprobe_blacklist_entry *ent;
Masami Hiramatsud81b4252014-07-17 11:44:11 +00002040 unsigned long entry, offset = 0, size = 0;
Masami Hiramatsu376e2422014-04-17 17:17:05 +09002041
2042 for (iter = start; iter < end; iter++) {
Masami Hiramatsud81b4252014-07-17 11:44:11 +00002043 entry = arch_deref_entry_point((void *)*iter);
2044
2045 if (!kernel_text_address(entry) ||
2046 !kallsyms_lookup_size_offset(entry, &size, &offset)) {
2047 pr_err("Failed to find blacklist at %p\n",
2048 (void *)entry);
Masami Hiramatsu376e2422014-04-17 17:17:05 +09002049 continue;
2050 }
2051
2052 ent = kmalloc(sizeof(*ent), GFP_KERNEL);
2053 if (!ent)
2054 return -ENOMEM;
Masami Hiramatsud81b4252014-07-17 11:44:11 +00002055 ent->start_addr = entry;
2056 ent->end_addr = entry + size;
Masami Hiramatsu376e2422014-04-17 17:17:05 +09002057 INIT_LIST_HEAD(&ent->list);
2058 list_add_tail(&ent->list, &kprobe_blacklist);
2059 }
2060 return 0;
2061}
2062
Masami Hiramatsue8386a02009-01-06 14:41:52 -08002063/* Module notifier call back, checking kprobes on the module */
Masami Hiramatsu55479f62014-04-17 17:17:54 +09002064static int kprobes_module_callback(struct notifier_block *nb,
2065 unsigned long val, void *data)
Masami Hiramatsue8386a02009-01-06 14:41:52 -08002066{
2067 struct module *mod = data;
2068 struct hlist_head *head;
Masami Hiramatsue8386a02009-01-06 14:41:52 -08002069 struct kprobe *p;
2070 unsigned int i;
Masami Hiramatsuf24659d2009-01-06 14:41:55 -08002071 int checkcore = (val == MODULE_STATE_GOING);
Masami Hiramatsue8386a02009-01-06 14:41:52 -08002072
Masami Hiramatsuf24659d2009-01-06 14:41:55 -08002073 if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
Masami Hiramatsue8386a02009-01-06 14:41:52 -08002074 return NOTIFY_DONE;
2075
2076 /*
Masami Hiramatsuf24659d2009-01-06 14:41:55 -08002077 * When MODULE_STATE_GOING was notified, both of module .text and
2078 * .init.text sections would be freed. When MODULE_STATE_LIVE was
2079 * notified, only .init.text section would be freed. We need to
2080 * disable kprobes which have been inserted in the sections.
Masami Hiramatsue8386a02009-01-06 14:41:52 -08002081 */
2082 mutex_lock(&kprobe_mutex);
2083 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2084 head = &kprobe_table[i];
Sasha Levinb67bfe02013-02-27 17:06:00 -08002085 hlist_for_each_entry_rcu(p, head, hlist)
Masami Hiramatsuf24659d2009-01-06 14:41:55 -08002086 if (within_module_init((unsigned long)p->addr, mod) ||
2087 (checkcore &&
2088 within_module_core((unsigned long)p->addr, mod))) {
Masami Hiramatsue8386a02009-01-06 14:41:52 -08002089 /*
2090 * The vaddr this probe is installed will soon
2091 * be vfreed buy not synced to disk. Hence,
2092 * disarming the breakpoint isn't needed.
2093 */
2094 kill_kprobe(p);
2095 }
2096 }
2097 mutex_unlock(&kprobe_mutex);
2098 return NOTIFY_DONE;
2099}
2100
2101static struct notifier_block kprobe_module_nb = {
2102 .notifier_call = kprobes_module_callback,
2103 .priority = 0
2104};
2105
Masami Hiramatsu376e2422014-04-17 17:17:05 +09002106/* Markers of _kprobe_blacklist section */
2107extern unsigned long __start_kprobe_blacklist[];
2108extern unsigned long __stop_kprobe_blacklist[];
2109
Linus Torvalds1da177e2005-04-16 15:20:36 -07002110static int __init init_kprobes(void)
2111{
2112 int i, err = 0;
2113
2114 /* FIXME allocate the probe table, currently defined statically */
2115 /* initialize all list heads */
Hien Nguyenb94cce92005-06-23 00:09:19 -07002116 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002117 INIT_HLIST_HEAD(&kprobe_table[i]);
Hien Nguyenb94cce92005-06-23 00:09:19 -07002118 INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
Thomas Gleixnerec4846082009-07-25 16:09:17 +02002119 raw_spin_lock_init(&(kretprobe_table_locks[i].lock));
Hien Nguyenb94cce92005-06-23 00:09:19 -07002120 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002121
Masami Hiramatsu376e2422014-04-17 17:17:05 +09002122 err = populate_kprobe_blacklist(__start_kprobe_blacklist,
2123 __stop_kprobe_blacklist);
2124 if (err) {
2125 pr_err("kprobes: failed to populate blacklist: %d\n", err);
2126 pr_err("Please take care of using kprobes.\n");
Srinivasa Ds3d8d9962008-04-28 02:14:26 -07002127 }
2128
Masami Hiramatsuf438d912007-10-16 01:27:49 -07002129 if (kretprobe_blacklist_size) {
2130 /* lookup the function address from its name */
2131 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
2132 kprobe_lookup_name(kretprobe_blacklist[i].name,
2133 kretprobe_blacklist[i].addr);
2134 if (!kretprobe_blacklist[i].addr)
2135 printk("kretprobe: lookup failed: %s\n",
2136 kretprobe_blacklist[i].name);
2137 }
2138 }
2139
Masami Hiramatsub2be84d2010-02-25 08:34:15 -05002140#if defined(CONFIG_OPTPROBES)
2141#if defined(__ARCH_WANT_KPROBES_INSN_SLOT)
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002142 /* Init kprobe_optinsn_slots */
2143 kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
2144#endif
Masami Hiramatsub2be84d2010-02-25 08:34:15 -05002145 /* By default, kprobes can be optimized */
2146 kprobes_allow_optimization = true;
2147#endif
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002148
Masami Hiramatsue579abe2009-04-06 19:01:01 -07002149 /* By default, kprobes are armed */
2150 kprobes_all_disarmed = false;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002151
Rusty Lynch67729262005-07-05 18:54:50 -07002152 err = arch_init_kprobes();
Rusty Lynch802eae72005-06-27 15:17:08 -07002153 if (!err)
2154 err = register_die_notifier(&kprobe_exceptions_nb);
Masami Hiramatsue8386a02009-01-06 14:41:52 -08002155 if (!err)
2156 err = register_module_notifier(&kprobe_module_nb);
2157
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07002158 kprobes_initialized = (err == 0);
Rusty Lynch802eae72005-06-27 15:17:08 -07002159
Ananth N Mavinakayanahalli8c1c9352008-01-30 13:32:53 +01002160 if (!err)
2161 init_test_probes();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002162 return err;
2163}
2164
Srinivasa Ds346fd592007-02-20 13:57:54 -08002165#ifdef CONFIG_DEBUG_FS
Masami Hiramatsu55479f62014-04-17 17:17:54 +09002166static void report_probe(struct seq_file *pi, struct kprobe *p,
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002167 const char *sym, int offset, char *modname, struct kprobe *pp)
Srinivasa Ds346fd592007-02-20 13:57:54 -08002168{
2169 char *kprobe_type;
2170
2171 if (p->pre_handler == pre_handler_kretprobe)
2172 kprobe_type = "r";
2173 else if (p->pre_handler == setjmp_pre_handler)
2174 kprobe_type = "j";
2175 else
2176 kprobe_type = "k";
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002177
Srinivasa Ds346fd592007-02-20 13:57:54 -08002178 if (sym)
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002179 seq_printf(pi, "%p %s %s+0x%x %s ",
Masami Hiramatsude5bd882009-04-06 19:01:02 -07002180 p->addr, kprobe_type, sym, offset,
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002181 (modname ? modname : " "));
Srinivasa Ds346fd592007-02-20 13:57:54 -08002182 else
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002183 seq_printf(pi, "%p %s %p ",
2184 p->addr, kprobe_type, p->addr);
2185
2186 if (!pp)
2187 pp = p;
Masami Hiramatsuae6aa162012-06-05 19:28:32 +09002188 seq_printf(pi, "%s%s%s%s\n",
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002189 (kprobe_gone(p) ? "[GONE]" : ""),
2190 ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""),
Masami Hiramatsuae6aa162012-06-05 19:28:32 +09002191 (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""),
2192 (kprobe_ftrace(pp) ? "[FTRACE]" : ""));
Srinivasa Ds346fd592007-02-20 13:57:54 -08002193}
2194
Masami Hiramatsu55479f62014-04-17 17:17:54 +09002195static void *kprobe_seq_start(struct seq_file *f, loff_t *pos)
Srinivasa Ds346fd592007-02-20 13:57:54 -08002196{
2197 return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
2198}
2199
Masami Hiramatsu55479f62014-04-17 17:17:54 +09002200static void *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
Srinivasa Ds346fd592007-02-20 13:57:54 -08002201{
2202 (*pos)++;
2203 if (*pos >= KPROBE_TABLE_SIZE)
2204 return NULL;
2205 return pos;
2206}
2207
Masami Hiramatsu55479f62014-04-17 17:17:54 +09002208static void kprobe_seq_stop(struct seq_file *f, void *v)
Srinivasa Ds346fd592007-02-20 13:57:54 -08002209{
2210 /* Nothing to do */
2211}
2212
Masami Hiramatsu55479f62014-04-17 17:17:54 +09002213static int show_kprobe_addr(struct seq_file *pi, void *v)
Srinivasa Ds346fd592007-02-20 13:57:54 -08002214{
2215 struct hlist_head *head;
Srinivasa Ds346fd592007-02-20 13:57:54 -08002216 struct kprobe *p, *kp;
2217 const char *sym = NULL;
2218 unsigned int i = *(loff_t *) v;
Alexey Dobriyanffb45122007-05-08 00:28:41 -07002219 unsigned long offset = 0;
Joe Marioab767862013-11-12 15:10:23 -08002220 char *modname, namebuf[KSYM_NAME_LEN];
Srinivasa Ds346fd592007-02-20 13:57:54 -08002221
2222 head = &kprobe_table[i];
2223 preempt_disable();
Sasha Levinb67bfe02013-02-27 17:06:00 -08002224 hlist_for_each_entry_rcu(p, head, hlist) {
Alexey Dobriyanffb45122007-05-08 00:28:41 -07002225 sym = kallsyms_lookup((unsigned long)p->addr, NULL,
Srinivasa Ds346fd592007-02-20 13:57:54 -08002226 &offset, &modname, namebuf);
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002227 if (kprobe_aggrprobe(p)) {
Srinivasa Ds346fd592007-02-20 13:57:54 -08002228 list_for_each_entry_rcu(kp, &p->list, list)
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002229 report_probe(pi, kp, sym, offset, modname, p);
Srinivasa Ds346fd592007-02-20 13:57:54 -08002230 } else
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002231 report_probe(pi, p, sym, offset, modname, NULL);
Srinivasa Ds346fd592007-02-20 13:57:54 -08002232 }
2233 preempt_enable();
2234 return 0;
2235}
2236
James Morris88e9d342009-09-22 16:43:43 -07002237static const struct seq_operations kprobes_seq_ops = {
Srinivasa Ds346fd592007-02-20 13:57:54 -08002238 .start = kprobe_seq_start,
2239 .next = kprobe_seq_next,
2240 .stop = kprobe_seq_stop,
2241 .show = show_kprobe_addr
2242};
2243
Masami Hiramatsu55479f62014-04-17 17:17:54 +09002244static int kprobes_open(struct inode *inode, struct file *filp)
Srinivasa Ds346fd592007-02-20 13:57:54 -08002245{
2246 return seq_open(filp, &kprobes_seq_ops);
2247}
2248
Alexey Dobriyan828c0952009-10-01 15:43:56 -07002249static const struct file_operations debugfs_kprobes_operations = {
Srinivasa Ds346fd592007-02-20 13:57:54 -08002250 .open = kprobes_open,
2251 .read = seq_read,
2252 .llseek = seq_lseek,
2253 .release = seq_release,
2254};
2255
Masami Hiramatsu63724742014-04-17 17:18:49 +09002256/* kprobes/blacklist -- shows which functions can not be probed */
2257static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos)
2258{
2259 return seq_list_start(&kprobe_blacklist, *pos);
2260}
2261
2262static void *kprobe_blacklist_seq_next(struct seq_file *m, void *v, loff_t *pos)
2263{
2264 return seq_list_next(v, &kprobe_blacklist, pos);
2265}
2266
2267static int kprobe_blacklist_seq_show(struct seq_file *m, void *v)
2268{
2269 struct kprobe_blacklist_entry *ent =
2270 list_entry(v, struct kprobe_blacklist_entry, list);
2271
2272 seq_printf(m, "0x%p-0x%p\t%ps\n", (void *)ent->start_addr,
2273 (void *)ent->end_addr, (void *)ent->start_addr);
2274 return 0;
2275}
2276
2277static const struct seq_operations kprobe_blacklist_seq_ops = {
2278 .start = kprobe_blacklist_seq_start,
2279 .next = kprobe_blacklist_seq_next,
2280 .stop = kprobe_seq_stop, /* Reuse void function */
2281 .show = kprobe_blacklist_seq_show,
2282};
2283
2284static int kprobe_blacklist_open(struct inode *inode, struct file *filp)
2285{
2286 return seq_open(filp, &kprobe_blacklist_seq_ops);
2287}
2288
2289static const struct file_operations debugfs_kprobe_blacklist_ops = {
2290 .open = kprobe_blacklist_open,
2291 .read = seq_read,
2292 .llseek = seq_lseek,
2293 .release = seq_release,
2294};
2295
Masami Hiramatsu55479f62014-04-17 17:17:54 +09002296static void arm_all_kprobes(void)
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002297{
2298 struct hlist_head *head;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002299 struct kprobe *p;
2300 unsigned int i;
2301
2302 mutex_lock(&kprobe_mutex);
2303
Masami Hiramatsue579abe2009-04-06 19:01:01 -07002304 /* If kprobes are armed, just return */
2305 if (!kprobes_all_disarmed)
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002306 goto already_enabled;
2307
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002308 /* Arming kprobes doesn't optimize kprobe itself */
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002309 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2310 head = &kprobe_table[i];
Sasha Levinb67bfe02013-02-27 17:06:00 -08002311 hlist_for_each_entry_rcu(p, head, hlist)
Masami Hiramatsude5bd882009-04-06 19:01:02 -07002312 if (!kprobe_disabled(p))
Masami Hiramatsuae6aa162012-06-05 19:28:32 +09002313 arm_kprobe(p);
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002314 }
2315
Masami Hiramatsue579abe2009-04-06 19:01:01 -07002316 kprobes_all_disarmed = false;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002317 printk(KERN_INFO "Kprobes globally enabled\n");
2318
2319already_enabled:
2320 mutex_unlock(&kprobe_mutex);
2321 return;
2322}
2323
Masami Hiramatsu55479f62014-04-17 17:17:54 +09002324static void disarm_all_kprobes(void)
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002325{
2326 struct hlist_head *head;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002327 struct kprobe *p;
2328 unsigned int i;
2329
2330 mutex_lock(&kprobe_mutex);
2331
Masami Hiramatsue579abe2009-04-06 19:01:01 -07002332 /* If kprobes are already disarmed, just return */
Masami Hiramatsu6274de42010-12-03 18:54:09 +09002333 if (kprobes_all_disarmed) {
2334 mutex_unlock(&kprobe_mutex);
2335 return;
2336 }
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002337
Masami Hiramatsue579abe2009-04-06 19:01:01 -07002338 kprobes_all_disarmed = true;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002339 printk(KERN_INFO "Kprobes globally disabled\n");
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002340
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002341 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2342 head = &kprobe_table[i];
Sasha Levinb67bfe02013-02-27 17:06:00 -08002343 hlist_for_each_entry_rcu(p, head, hlist) {
Masami Hiramatsude5bd882009-04-06 19:01:02 -07002344 if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p))
Masami Hiramatsuae6aa162012-06-05 19:28:32 +09002345 disarm_kprobe(p, false);
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002346 }
2347 }
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002348 mutex_unlock(&kprobe_mutex);
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002349
Masami Hiramatsu6274de42010-12-03 18:54:09 +09002350 /* Wait for disarming all kprobes by optimizer */
2351 wait_for_kprobe_optimizer();
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002352}
2353
2354/*
2355 * XXX: The debugfs bool file interface doesn't allow for callbacks
2356 * when the bool state is switched. We can reuse that facility when
2357 * available
2358 */
2359static ssize_t read_enabled_file_bool(struct file *file,
2360 char __user *user_buf, size_t count, loff_t *ppos)
2361{
2362 char buf[3];
2363
Masami Hiramatsue579abe2009-04-06 19:01:01 -07002364 if (!kprobes_all_disarmed)
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002365 buf[0] = '1';
2366 else
2367 buf[0] = '0';
2368 buf[1] = '\n';
2369 buf[2] = 0x00;
2370 return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
2371}
2372
2373static ssize_t write_enabled_file_bool(struct file *file,
2374 const char __user *user_buf, size_t count, loff_t *ppos)
2375{
2376 char buf[32];
Stephen Boydefeb1562012-01-12 17:17:11 -08002377 size_t buf_size;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002378
2379 buf_size = min(count, (sizeof(buf)-1));
2380 if (copy_from_user(buf, user_buf, buf_size))
2381 return -EFAULT;
2382
Mathias Krause10fb46d2013-07-03 15:05:39 -07002383 buf[buf_size] = '\0';
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002384 switch (buf[0]) {
2385 case 'y':
2386 case 'Y':
2387 case '1':
Masami Hiramatsue579abe2009-04-06 19:01:01 -07002388 arm_all_kprobes();
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002389 break;
2390 case 'n':
2391 case 'N':
2392 case '0':
Masami Hiramatsue579abe2009-04-06 19:01:01 -07002393 disarm_all_kprobes();
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002394 break;
Mathias Krause10fb46d2013-07-03 15:05:39 -07002395 default:
2396 return -EINVAL;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002397 }
2398
2399 return count;
2400}
2401
Alexey Dobriyan828c0952009-10-01 15:43:56 -07002402static const struct file_operations fops_kp = {
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002403 .read = read_enabled_file_bool,
2404 .write = write_enabled_file_bool,
Arnd Bergmann6038f372010-08-15 18:52:59 +02002405 .llseek = default_llseek,
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002406};
2407
Masami Hiramatsu55479f62014-04-17 17:17:54 +09002408static int __init debugfs_kprobe_init(void)
Srinivasa Ds346fd592007-02-20 13:57:54 -08002409{
2410 struct dentry *dir, *file;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002411 unsigned int value = 1;
Srinivasa Ds346fd592007-02-20 13:57:54 -08002412
2413 dir = debugfs_create_dir("kprobes", NULL);
2414 if (!dir)
2415 return -ENOMEM;
2416
Randy Dunlape3869792007-05-08 00:27:01 -07002417 file = debugfs_create_file("list", 0444, dir, NULL,
Srinivasa Ds346fd592007-02-20 13:57:54 -08002418 &debugfs_kprobes_operations);
Masami Hiramatsu63724742014-04-17 17:18:49 +09002419 if (!file)
2420 goto error;
Srinivasa Ds346fd592007-02-20 13:57:54 -08002421
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002422 file = debugfs_create_file("enabled", 0600, dir,
2423 &value, &fops_kp);
Masami Hiramatsu63724742014-04-17 17:18:49 +09002424 if (!file)
2425 goto error;
2426
2427 file = debugfs_create_file("blacklist", 0444, dir, NULL,
2428 &debugfs_kprobe_blacklist_ops);
2429 if (!file)
2430 goto error;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002431
Srinivasa Ds346fd592007-02-20 13:57:54 -08002432 return 0;
Masami Hiramatsu63724742014-04-17 17:18:49 +09002433
2434error:
2435 debugfs_remove(dir);
2436 return -ENOMEM;
Srinivasa Ds346fd592007-02-20 13:57:54 -08002437}
2438
2439late_initcall(debugfs_kprobe_init);
2440#endif /* CONFIG_DEBUG_FS */
2441
2442module_init(init_kprobes);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002443
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07002444/* defined in arch/.../kernel/kprobes.c */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002445EXPORT_SYMBOL_GPL(jprobe_return);