blob: 098f396aa40984d0b49f246b45dd059b88e9acdf [file] [log] [blame]
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
Srinivasa Ds3d8d9962008-04-28 02:14:26 -070089/*
90 * Normally, functions that we'd want to prohibit kprobes in, are marked
91 * __kprobes. But, there are cases where such functions already belong to
92 * a different section (__sched for preempt_schedule)
93 *
94 * For such cases, we now have a blacklist
95 */
Daniel Guilak544304b2008-07-10 09:38:19 -070096static struct kprobe_blackpoint kprobe_blacklist[] = {
Srinivasa Ds3d8d9962008-04-28 02:14:26 -070097 {"preempt_schedule",},
Masami Hiramatsu65e234e2009-08-27 13:23:32 -040098 {"native_get_debugreg",},
Masami Hiramatsua00e8172009-09-08 12:47:55 -040099 {"irq_entries_start",},
100 {"common_interrupt",},
Masami Hiramatsu5ecaafd2010-02-05 01:24:34 -0500101 {"mcount",}, /* mcount can be called from everywhere */
Srinivasa Ds3d8d9962008-04-28 02:14:26 -0700102 {NULL} /* Terminator */
103};
104
Anil S Keshavamurthy2d14e392006-01-09 20:52:41 -0800105#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700106/*
107 * kprobe->ainsn.insn points to the copy of the instruction to be
108 * single-stepped. x86_64, POWER4 and above have no-exec support and
109 * stepping on the instruction on a vmalloced/kmalloced/data page
110 * is a recipe for disaster
111 */
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700112struct kprobe_insn_page {
Masami Hiramatsuc5cb5a22009-06-30 17:08:14 -0400113 struct list_head list;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700114 kprobe_opcode_t *insns; /* Page of instruction slots */
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700115 int nused;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800116 int ngarbage;
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500117 char slot_used[];
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700118};
119
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500120#define KPROBE_INSN_PAGE_SIZE(slots) \
121 (offsetof(struct kprobe_insn_page, slot_used) + \
122 (sizeof(char) * (slots)))
123
124struct kprobe_insn_cache {
125 struct list_head pages; /* list of kprobe_insn_page */
126 size_t insn_size; /* size of instruction slot */
127 int nr_garbage;
128};
129
130static int slots_per_page(struct kprobe_insn_cache *c)
131{
132 return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t));
133}
134
Masami Hiramatsuab40c5c2007-01-30 14:36:06 -0800135enum kprobe_slot_state {
136 SLOT_CLEAN = 0,
137 SLOT_DIRTY = 1,
138 SLOT_USED = 2,
139};
140
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500141static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_slots */
142static struct kprobe_insn_cache kprobe_insn_slots = {
143 .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages),
144 .insn_size = MAX_INSN_SIZE,
145 .nr_garbage = 0,
146};
147static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c);
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800148
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700149/**
Masami Hiramatsu12941562009-01-06 14:41:50 -0800150 * __get_insn_slot() - Find a slot on an executable page for an instruction.
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700151 * We allocate an executable page if there's no room on existing ones.
152 */
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500153static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c)
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700154{
155 struct kprobe_insn_page *kip;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700156
Christoph Hellwig6f716ac2007-05-08 00:34:13 -0700157 retry:
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500158 list_for_each_entry(kip, &c->pages, list) {
159 if (kip->nused < slots_per_page(c)) {
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700160 int i;
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500161 for (i = 0; i < slots_per_page(c); i++) {
Masami Hiramatsuab40c5c2007-01-30 14:36:06 -0800162 if (kip->slot_used[i] == SLOT_CLEAN) {
163 kip->slot_used[i] = SLOT_USED;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700164 kip->nused++;
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500165 return kip->insns + (i * c->insn_size);
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700166 }
167 }
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500168 /* kip->nused is broken. Fix it. */
169 kip->nused = slots_per_page(c);
170 WARN_ON(1);
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700171 }
172 }
173
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800174 /* If there are any garbage slots, collect it and try again. */
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500175 if (c->nr_garbage && collect_garbage_slots(c) == 0)
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800176 goto retry;
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500177
178 /* All out of space. Need to allocate a new page. */
179 kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL);
Christoph Hellwig6f716ac2007-05-08 00:34:13 -0700180 if (!kip)
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700181 return NULL;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700182
183 /*
184 * Use module_alloc so this page is within +/- 2GB of where the
185 * kernel image and loaded module images reside. This is required
186 * so x86_64 can correctly handle the %rip-relative fixups.
187 */
188 kip->insns = module_alloc(PAGE_SIZE);
189 if (!kip->insns) {
190 kfree(kip);
191 return NULL;
192 }
Masami Hiramatsuc5cb5a22009-06-30 17:08:14 -0400193 INIT_LIST_HEAD(&kip->list);
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500194 memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c));
Masami Hiramatsuab40c5c2007-01-30 14:36:06 -0800195 kip->slot_used[0] = SLOT_USED;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700196 kip->nused = 1;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800197 kip->ngarbage = 0;
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500198 list_add(&kip->list, &c->pages);
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700199 return kip->insns;
200}
201
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500202
Masami Hiramatsu12941562009-01-06 14:41:50 -0800203kprobe_opcode_t __kprobes *get_insn_slot(void)
204{
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500205 kprobe_opcode_t *ret = NULL;
206
Masami Hiramatsu12941562009-01-06 14:41:50 -0800207 mutex_lock(&kprobe_insn_mutex);
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500208 ret = __get_insn_slot(&kprobe_insn_slots);
Masami Hiramatsu12941562009-01-06 14:41:50 -0800209 mutex_unlock(&kprobe_insn_mutex);
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500210
Masami Hiramatsu12941562009-01-06 14:41:50 -0800211 return ret;
212}
213
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800214/* Return 1 if all garbages are collected, otherwise 0. */
215static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
216{
Masami Hiramatsuab40c5c2007-01-30 14:36:06 -0800217 kip->slot_used[idx] = SLOT_CLEAN;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800218 kip->nused--;
219 if (kip->nused == 0) {
220 /*
221 * Page is no longer in use. Free it unless
222 * it's the last one. We keep the last one
223 * so as not to have to set it up again the
224 * next time somebody inserts a probe.
225 */
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500226 if (!list_is_singular(&kip->list)) {
Masami Hiramatsuc5cb5a22009-06-30 17:08:14 -0400227 list_del(&kip->list);
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800228 module_free(NULL, kip->insns);
229 kfree(kip);
230 }
231 return 1;
232 }
233 return 0;
234}
235
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500236static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c)
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800237{
Masami Hiramatsuc5cb5a22009-06-30 17:08:14 -0400238 struct kprobe_insn_page *kip, *next;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800239
Masami Hiramatsu615d0eb2010-02-02 16:49:04 -0500240 /* Ensure no-one is interrupted on the garbages */
241 synchronize_sched();
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800242
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500243 list_for_each_entry_safe(kip, next, &c->pages, list) {
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800244 int i;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800245 if (kip->ngarbage == 0)
246 continue;
247 kip->ngarbage = 0; /* we will collect all garbages */
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500248 for (i = 0; i < slots_per_page(c); i++) {
Masami Hiramatsuab40c5c2007-01-30 14:36:06 -0800249 if (kip->slot_used[i] == SLOT_DIRTY &&
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800250 collect_one_slot(kip, i))
251 break;
252 }
253 }
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500254 c->nr_garbage = 0;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800255 return 0;
256}
257
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500258static void __kprobes __free_insn_slot(struct kprobe_insn_cache *c,
259 kprobe_opcode_t *slot, int dirty)
260{
261 struct kprobe_insn_page *kip;
262
263 list_for_each_entry(kip, &c->pages, list) {
Masami Hiramatsu83ff56f2010-03-09 10:22:19 -0500264 long idx = ((long)slot - (long)kip->insns) /
265 (c->insn_size * sizeof(kprobe_opcode_t));
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500266 if (idx >= 0 && idx < slots_per_page(c)) {
267 WARN_ON(kip->slot_used[idx] != SLOT_USED);
268 if (dirty) {
269 kip->slot_used[idx] = SLOT_DIRTY;
270 kip->ngarbage++;
271 if (++c->nr_garbage > slots_per_page(c))
272 collect_garbage_slots(c);
273 } else
274 collect_one_slot(kip, idx);
275 return;
276 }
277 }
278 /* Could not free this slot. */
279 WARN_ON(1);
280}
281
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800282void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700283{
Masami Hiramatsu12941562009-01-06 14:41:50 -0800284 mutex_lock(&kprobe_insn_mutex);
Masami Hiramatsu4610ee12010-02-25 08:33:59 -0500285 __free_insn_slot(&kprobe_insn_slots, slot, dirty);
Masami Hiramatsu12941562009-01-06 14:41:50 -0800286 mutex_unlock(&kprobe_insn_mutex);
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700287}
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500288#ifdef CONFIG_OPTPROBES
289/* For optimized_kprobe buffer */
290static DEFINE_MUTEX(kprobe_optinsn_mutex); /* Protects kprobe_optinsn_slots */
291static struct kprobe_insn_cache kprobe_optinsn_slots = {
292 .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
293 /* .insn_size is initialized later */
294 .nr_garbage = 0,
295};
296/* Get a slot for optimized_kprobe buffer */
297kprobe_opcode_t __kprobes *get_optinsn_slot(void)
298{
299 kprobe_opcode_t *ret = NULL;
300
301 mutex_lock(&kprobe_optinsn_mutex);
302 ret = __get_insn_slot(&kprobe_optinsn_slots);
303 mutex_unlock(&kprobe_optinsn_mutex);
304
305 return ret;
306}
307
308void __kprobes free_optinsn_slot(kprobe_opcode_t * slot, int dirty)
309{
310 mutex_lock(&kprobe_optinsn_mutex);
311 __free_insn_slot(&kprobe_optinsn_slots, slot, dirty);
312 mutex_unlock(&kprobe_optinsn_mutex);
313}
314#endif
Anil S Keshavamurthy2d14e392006-01-09 20:52:41 -0800315#endif
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700316
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800317/* We have preemption disabled.. so it is safe to use __ versions */
318static inline void set_kprobe_instance(struct kprobe *kp)
319{
Christoph Lameterb76834b2010-12-06 11:16:25 -0600320 __this_cpu_write(kprobe_instance, kp);
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800321}
322
323static inline void reset_kprobe_instance(void)
324{
Christoph Lameterb76834b2010-12-06 11:16:25 -0600325 __this_cpu_write(kprobe_instance, NULL);
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800326}
327
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800328/*
329 * This routine is called either:
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -0800330 * - under the kprobe_mutex - during kprobe_[un]register()
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800331 * OR
Ananth N Mavinakayanahallid217d542005-11-07 01:00:14 -0800332 * - with preemption disabled - from arch/xxx/kernel/kprobes.c
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800333 */
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700334struct kprobe __kprobes *get_kprobe(void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335{
336 struct hlist_head *head;
337 struct hlist_node *node;
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800338 struct kprobe *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339
340 head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800341 hlist_for_each_entry_rcu(p, node, head, hlist) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 if (p->addr == addr)
343 return p;
344 }
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500345
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 return NULL;
347}
348
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500349static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs);
350
351/* Return true if the kprobe is an aggregator */
352static inline int kprobe_aggrprobe(struct kprobe *p)
353{
354 return p->pre_handler == aggr_pre_handler;
355}
356
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900357/* Return true(!0) if the kprobe is unused */
358static inline int kprobe_unused(struct kprobe *p)
359{
360 return kprobe_aggrprobe(p) && kprobe_disabled(p) &&
361 list_empty(&p->list);
362}
363
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500364/*
365 * Keep all fields in the kprobe consistent
366 */
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +0900367static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500368{
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +0900369 memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t));
370 memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn));
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500371}
372
373#ifdef CONFIG_OPTPROBES
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500374/* NOTE: change this value only with kprobe_mutex held */
375static bool kprobes_allow_optimization;
376
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500377/*
378 * Call all pre_handler on the list, but ignores its return value.
379 * This must be called from arch-dep optimized caller.
380 */
381void __kprobes opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
382{
383 struct kprobe *kp;
384
385 list_for_each_entry_rcu(kp, &p->list, list) {
386 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
387 set_kprobe_instance(kp);
388 kp->pre_handler(kp, regs);
389 }
390 reset_kprobe_instance();
391 }
392}
393
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900394/* Free optimized instructions and optimized_kprobe */
395static __kprobes void free_aggr_kprobe(struct kprobe *p)
396{
397 struct optimized_kprobe *op;
398
399 op = container_of(p, struct optimized_kprobe, kp);
400 arch_remove_optimized_kprobe(op);
401 arch_remove_kprobe(p);
402 kfree(op);
403}
404
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500405/* Return true(!0) if the kprobe is ready for optimization. */
406static inline int kprobe_optready(struct kprobe *p)
407{
408 struct optimized_kprobe *op;
409
410 if (kprobe_aggrprobe(p)) {
411 op = container_of(p, struct optimized_kprobe, kp);
412 return arch_prepared_optinsn(&op->optinsn);
413 }
414
415 return 0;
416}
417
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900418/* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */
419static inline int kprobe_disarmed(struct kprobe *p)
420{
421 struct optimized_kprobe *op;
422
423 /* If kprobe is not aggr/opt probe, just return kprobe is disabled */
424 if (!kprobe_aggrprobe(p))
425 return kprobe_disabled(p);
426
427 op = container_of(p, struct optimized_kprobe, kp);
428
429 return kprobe_disabled(p) && list_empty(&op->list);
430}
431
432/* Return true(!0) if the probe is queued on (un)optimizing lists */
433static int __kprobes kprobe_queued(struct kprobe *p)
434{
435 struct optimized_kprobe *op;
436
437 if (kprobe_aggrprobe(p)) {
438 op = container_of(p, struct optimized_kprobe, kp);
439 if (!list_empty(&op->list))
440 return 1;
441 }
442 return 0;
443}
444
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500445/*
446 * Return an optimized kprobe whose optimizing code replaces
447 * instructions including addr (exclude breakpoint).
448 */
Namhyung Kim6376b222010-09-15 10:04:28 +0900449static struct kprobe *__kprobes get_optimized_kprobe(unsigned long addr)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500450{
451 int i;
452 struct kprobe *p = NULL;
453 struct optimized_kprobe *op;
454
455 /* Don't check i == 0, since that is a breakpoint case. */
456 for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++)
457 p = get_kprobe((void *)(addr - i));
458
459 if (p && kprobe_optready(p)) {
460 op = container_of(p, struct optimized_kprobe, kp);
461 if (arch_within_optimized_kprobe(op, addr))
462 return p;
463 }
464
465 return NULL;
466}
467
468/* Optimization staging list, protected by kprobe_mutex */
469static LIST_HEAD(optimizing_list);
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900470static LIST_HEAD(unoptimizing_list);
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500471
472static void kprobe_optimizer(struct work_struct *work);
473static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900474static DECLARE_COMPLETION(optimizer_comp);
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500475#define OPTIMIZE_DELAY 5
476
Masami Hiramatsu61f4e132010-12-03 18:54:03 +0900477/*
478 * Optimize (replace a breakpoint with a jump) kprobes listed on
479 * optimizing_list.
480 */
481static __kprobes void do_optimize_kprobes(void)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500482{
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900483 /* Optimization never be done when disarmed */
484 if (kprobes_all_disarmed || !kprobes_allow_optimization ||
485 list_empty(&optimizing_list))
486 return;
487
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500488 /*
489 * The optimization/unoptimization refers online_cpus via
490 * stop_machine() and cpu-hotplug modifies online_cpus.
491 * And same time, text_mutex will be held in cpu-hotplug and here.
492 * This combination can cause a deadlock (cpu-hotplug try to lock
493 * text_mutex but stop_machine can not be done because online_cpus
494 * has been changed)
495 * To avoid this deadlock, we need to call get_online_cpus()
496 * for preventing cpu-hotplug outside of text_mutex locking.
497 */
498 get_online_cpus();
499 mutex_lock(&text_mutex);
Masami Hiramatsucd7ebe22010-12-03 18:54:28 +0900500 arch_optimize_kprobes(&optimizing_list);
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500501 mutex_unlock(&text_mutex);
502 put_online_cpus();
Masami Hiramatsu61f4e132010-12-03 18:54:03 +0900503}
504
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900505/*
506 * Unoptimize (replace a jump with a breakpoint and remove the breakpoint
507 * if need) kprobes listed on unoptimizing_list.
508 */
509static __kprobes void do_unoptimize_kprobes(struct list_head *free_list)
510{
511 struct optimized_kprobe *op, *tmp;
512
513 /* Unoptimization must be done anytime */
514 if (list_empty(&unoptimizing_list))
515 return;
516
517 /* Ditto to do_optimize_kprobes */
518 get_online_cpus();
519 mutex_lock(&text_mutex);
Masami Hiramatsuf984ba42010-12-03 18:54:34 +0900520 arch_unoptimize_kprobes(&unoptimizing_list, free_list);
521 /* Loop free_list for disarming */
522 list_for_each_entry_safe(op, tmp, free_list, list) {
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900523 /* Disarm probes if marked disabled */
524 if (kprobe_disabled(&op->kp))
525 arch_disarm_kprobe(&op->kp);
526 if (kprobe_unused(&op->kp)) {
527 /*
528 * Remove unused probes from hash list. After waiting
529 * for synchronization, these probes are reclaimed.
530 * (reclaiming is done by do_free_cleaned_kprobes.)
531 */
532 hlist_del_rcu(&op->kp.hlist);
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900533 } else
534 list_del_init(&op->list);
535 }
536 mutex_unlock(&text_mutex);
537 put_online_cpus();
538}
539
540/* Reclaim all kprobes on the free_list */
541static __kprobes void do_free_cleaned_kprobes(struct list_head *free_list)
542{
543 struct optimized_kprobe *op, *tmp;
544
545 list_for_each_entry_safe(op, tmp, free_list, list) {
546 BUG_ON(!kprobe_unused(&op->kp));
547 list_del_init(&op->list);
548 free_aggr_kprobe(&op->kp);
549 }
550}
551
552/* Start optimizer after OPTIMIZE_DELAY passed */
553static __kprobes void kick_kprobe_optimizer(void)
554{
555 if (!delayed_work_pending(&optimizing_work))
556 schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
557}
558
Masami Hiramatsu61f4e132010-12-03 18:54:03 +0900559/* Kprobe jump optimizer */
560static __kprobes void kprobe_optimizer(struct work_struct *work)
561{
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900562 LIST_HEAD(free_list);
563
Steven Rostedt72ef3792012-06-05 19:28:14 +0900564 mutex_lock(&kprobe_mutex);
Masami Hiramatsu61f4e132010-12-03 18:54:03 +0900565 /* Lock modules while optimizing kprobes */
566 mutex_lock(&module_mutex);
Masami Hiramatsu61f4e132010-12-03 18:54:03 +0900567
568 /*
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900569 * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
570 * kprobes before waiting for quiesence period.
571 */
572 do_unoptimize_kprobes(&free_list);
573
574 /*
575 * Step 2: Wait for quiesence period to ensure all running interrupts
Masami Hiramatsu61f4e132010-12-03 18:54:03 +0900576 * are done. Because optprobe may modify multiple instructions
577 * there is a chance that Nth instruction is interrupted. In that
578 * case, running interrupt can return to 2nd-Nth byte of jump
579 * instruction. This wait is for avoiding it.
580 */
581 synchronize_sched();
582
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900583 /* Step 3: Optimize kprobes after quiesence period */
Masami Hiramatsu61f4e132010-12-03 18:54:03 +0900584 do_optimize_kprobes();
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900585
586 /* Step 4: Free cleaned kprobes after quiesence period */
587 do_free_cleaned_kprobes(&free_list);
588
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500589 mutex_unlock(&module_mutex);
Steven Rostedt72ef3792012-06-05 19:28:14 +0900590 mutex_unlock(&kprobe_mutex);
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900591
Masami Hiramatsucd7ebe22010-12-03 18:54:28 +0900592 /* Step 5: Kick optimizer again if needed */
Masami Hiramatsuf984ba42010-12-03 18:54:34 +0900593 if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
Masami Hiramatsucd7ebe22010-12-03 18:54:28 +0900594 kick_kprobe_optimizer();
595 else
596 /* Wake up all waiters */
597 complete_all(&optimizer_comp);
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900598}
599
600/* Wait for completing optimization and unoptimization */
601static __kprobes void wait_for_kprobe_optimizer(void)
602{
603 if (delayed_work_pending(&optimizing_work))
604 wait_for_completion(&optimizer_comp);
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500605}
606
607/* Optimize kprobe if p is ready to be optimized */
608static __kprobes void optimize_kprobe(struct kprobe *p)
609{
610 struct optimized_kprobe *op;
611
612 /* Check if the kprobe is disabled or not ready for optimization. */
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500613 if (!kprobe_optready(p) || !kprobes_allow_optimization ||
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500614 (kprobe_disabled(p) || kprobes_all_disarmed))
615 return;
616
617 /* Both of break_handler and post_handler are not supported. */
618 if (p->break_handler || p->post_handler)
619 return;
620
621 op = container_of(p, struct optimized_kprobe, kp);
622
623 /* Check there is no other kprobes at the optimized instructions */
624 if (arch_check_optimized_kprobe(op) < 0)
625 return;
626
627 /* Check if it is already optimized. */
628 if (op->kp.flags & KPROBE_FLAG_OPTIMIZED)
629 return;
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500630 op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900631
632 if (!list_empty(&op->list))
633 /* This is under unoptimizing. Just dequeue the probe */
634 list_del_init(&op->list);
635 else {
636 list_add(&op->list, &optimizing_list);
637 kick_kprobe_optimizer();
638 }
639}
640
641/* Short cut to direct unoptimizing */
642static __kprobes void force_unoptimize_kprobe(struct optimized_kprobe *op)
643{
644 get_online_cpus();
645 arch_unoptimize_kprobe(op);
646 put_online_cpus();
647 if (kprobe_disabled(&op->kp))
648 arch_disarm_kprobe(&op->kp);
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500649}
650
651/* Unoptimize a kprobe if p is optimized */
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900652static __kprobes void unoptimize_kprobe(struct kprobe *p, bool force)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500653{
654 struct optimized_kprobe *op;
655
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900656 if (!kprobe_aggrprobe(p) || kprobe_disarmed(p))
657 return; /* This is not an optprobe nor optimized */
658
659 op = container_of(p, struct optimized_kprobe, kp);
660 if (!kprobe_optimized(p)) {
661 /* Unoptimized or unoptimizing case */
662 if (force && !list_empty(&op->list)) {
663 /*
664 * Only if this is unoptimizing kprobe and forced,
665 * forcibly unoptimize it. (No need to unoptimize
666 * unoptimized kprobe again :)
667 */
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500668 list_del_init(&op->list);
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900669 force_unoptimize_kprobe(op);
670 }
671 return;
672 }
673
674 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
675 if (!list_empty(&op->list)) {
676 /* Dequeue from the optimization queue */
677 list_del_init(&op->list);
678 return;
679 }
680 /* Optimized kprobe case */
681 if (force)
682 /* Forcibly update the code: this is a special case */
683 force_unoptimize_kprobe(op);
684 else {
685 list_add(&op->list, &unoptimizing_list);
686 kick_kprobe_optimizer();
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500687 }
688}
689
Masami Hiramatsu0490cd12010-12-03 18:54:16 +0900690/* Cancel unoptimizing for reusing */
691static void reuse_unused_kprobe(struct kprobe *ap)
692{
693 struct optimized_kprobe *op;
694
695 BUG_ON(!kprobe_unused(ap));
696 /*
697 * Unused kprobe MUST be on the way of delayed unoptimizing (means
698 * there is still a relative jump) and disabled.
699 */
700 op = container_of(ap, struct optimized_kprobe, kp);
701 if (unlikely(list_empty(&op->list)))
702 printk(KERN_WARNING "Warning: found a stray unused "
703 "aggrprobe@%p\n", ap->addr);
704 /* Enable the probe again */
705 ap->flags &= ~KPROBE_FLAG_DISABLED;
706 /* Optimize it again (remove from op->list) */
707 BUG_ON(!kprobe_optready(ap));
708 optimize_kprobe(ap);
709}
710
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500711/* Remove optimized instructions */
712static void __kprobes kill_optimized_kprobe(struct kprobe *p)
713{
714 struct optimized_kprobe *op;
715
716 op = container_of(p, struct optimized_kprobe, kp);
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900717 if (!list_empty(&op->list))
718 /* Dequeue from the (un)optimization queue */
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500719 list_del_init(&op->list);
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900720
721 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
722 /* Don't touch the code, because it is already freed. */
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500723 arch_remove_optimized_kprobe(op);
724}
725
726/* Try to prepare optimized instructions */
727static __kprobes void prepare_optimized_kprobe(struct kprobe *p)
728{
729 struct optimized_kprobe *op;
730
731 op = container_of(p, struct optimized_kprobe, kp);
732 arch_prepare_optimized_kprobe(op);
733}
734
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500735/* Allocate new optimized_kprobe and try to prepare optimized instructions */
736static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
737{
738 struct optimized_kprobe *op;
739
740 op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL);
741 if (!op)
742 return NULL;
743
744 INIT_LIST_HEAD(&op->list);
745 op->kp.addr = p->addr;
746 arch_prepare_optimized_kprobe(op);
747
748 return &op->kp;
749}
750
751static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p);
752
753/*
754 * Prepare an optimized_kprobe and optimize it
755 * NOTE: p must be a normal registered kprobe
756 */
757static __kprobes void try_to_optimize_kprobe(struct kprobe *p)
758{
759 struct kprobe *ap;
760 struct optimized_kprobe *op;
761
Masami Hiramatsuae6aa162012-06-05 19:28:32 +0900762 /* Impossible to optimize ftrace-based kprobe */
763 if (kprobe_ftrace(p))
764 return;
765
Masami Hiramatsu25764282012-06-05 19:28:26 +0900766 /* For preparing optimization, jump_label_text_reserved() is called */
767 jump_label_lock();
768 mutex_lock(&text_mutex);
769
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500770 ap = alloc_aggr_kprobe(p);
771 if (!ap)
Masami Hiramatsu25764282012-06-05 19:28:26 +0900772 goto out;
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500773
774 op = container_of(ap, struct optimized_kprobe, kp);
775 if (!arch_prepared_optinsn(&op->optinsn)) {
776 /* If failed to setup optimizing, fallback to kprobe */
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900777 arch_remove_optimized_kprobe(op);
778 kfree(op);
Masami Hiramatsu25764282012-06-05 19:28:26 +0900779 goto out;
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500780 }
781
782 init_aggr_kprobe(ap, p);
Masami Hiramatsu25764282012-06-05 19:28:26 +0900783 optimize_kprobe(ap); /* This just kicks optimizer thread */
784
785out:
786 mutex_unlock(&text_mutex);
787 jump_label_unlock();
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500788}
789
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500790#ifdef CONFIG_SYSCTL
Masami Hiramatsu43948f52010-10-25 22:18:01 +0900791/* This should be called with kprobe_mutex locked */
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500792static void __kprobes optimize_all_kprobes(void)
793{
794 struct hlist_head *head;
795 struct hlist_node *node;
796 struct kprobe *p;
797 unsigned int i;
798
799 /* If optimization is already allowed, just return */
800 if (kprobes_allow_optimization)
801 return;
802
803 kprobes_allow_optimization = true;
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500804 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
805 head = &kprobe_table[i];
806 hlist_for_each_entry_rcu(p, node, head, hlist)
807 if (!kprobe_disabled(p))
808 optimize_kprobe(p);
809 }
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500810 printk(KERN_INFO "Kprobes globally optimized\n");
811}
812
Masami Hiramatsu43948f52010-10-25 22:18:01 +0900813/* This should be called with kprobe_mutex locked */
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500814static void __kprobes unoptimize_all_kprobes(void)
815{
816 struct hlist_head *head;
817 struct hlist_node *node;
818 struct kprobe *p;
819 unsigned int i;
820
821 /* If optimization is already prohibited, just return */
822 if (!kprobes_allow_optimization)
823 return;
824
825 kprobes_allow_optimization = false;
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500826 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
827 head = &kprobe_table[i];
828 hlist_for_each_entry_rcu(p, node, head, hlist) {
829 if (!kprobe_disabled(p))
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900830 unoptimize_kprobe(p, false);
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500831 }
832 }
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900833 /* Wait for unoptimizing completion */
834 wait_for_kprobe_optimizer();
835 printk(KERN_INFO "Kprobes globally unoptimized\n");
Masami Hiramatsub2be84d2010-02-25 08:34:15 -0500836}
837
838int sysctl_kprobes_optimization;
839int proc_kprobes_optimization_handler(struct ctl_table *table, int write,
840 void __user *buffer, size_t *length,
841 loff_t *ppos)
842{
843 int ret;
844
845 mutex_lock(&kprobe_mutex);
846 sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0;
847 ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
848
849 if (sysctl_kprobes_optimization)
850 optimize_all_kprobes();
851 else
852 unoptimize_all_kprobes();
853 mutex_unlock(&kprobe_mutex);
854
855 return ret;
856}
857#endif /* CONFIG_SYSCTL */
858
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900859/* Put a breakpoint for a probe. Must be called with text_mutex locked */
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500860static void __kprobes __arm_kprobe(struct kprobe *p)
861{
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +0900862 struct kprobe *_p;
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500863
864 /* Check collision with other optimized kprobes */
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +0900865 _p = get_optimized_kprobe((unsigned long)p->addr);
866 if (unlikely(_p))
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900867 /* Fallback to unoptimized kprobe */
868 unoptimize_kprobe(_p, true);
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500869
870 arch_arm_kprobe(p);
871 optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */
872}
873
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900874/* Remove the breakpoint of a probe. Must be called with text_mutex locked */
875static void __kprobes __disarm_kprobe(struct kprobe *p, bool reopt)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500876{
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +0900877 struct kprobe *_p;
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500878
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900879 unoptimize_kprobe(p, false); /* Try to unoptimize */
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500880
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900881 if (!kprobe_queued(p)) {
882 arch_disarm_kprobe(p);
883 /* If another kprobe was blocked, optimize it. */
884 _p = get_optimized_kprobe((unsigned long)p->addr);
885 if (unlikely(_p) && reopt)
886 optimize_kprobe(_p);
887 }
888 /* TODO: reoptimize others after unoptimized this probe */
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500889}
890
891#else /* !CONFIG_OPTPROBES */
892
893#define optimize_kprobe(p) do {} while (0)
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900894#define unoptimize_kprobe(p, f) do {} while (0)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500895#define kill_optimized_kprobe(p) do {} while (0)
896#define prepare_optimized_kprobe(p) do {} while (0)
897#define try_to_optimize_kprobe(p) do {} while (0)
898#define __arm_kprobe(p) arch_arm_kprobe(p)
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900899#define __disarm_kprobe(p, o) arch_disarm_kprobe(p)
900#define kprobe_disarmed(p) kprobe_disabled(p)
901#define wait_for_kprobe_optimizer() do {} while (0)
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500902
Masami Hiramatsu0490cd12010-12-03 18:54:16 +0900903/* There should be no unused kprobes can be reused without optimization */
904static void reuse_unused_kprobe(struct kprobe *ap)
905{
906 printk(KERN_ERR "Error: There should be no unused kprobe here.\n");
907 BUG_ON(kprobe_unused(ap));
908}
909
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500910static __kprobes void free_aggr_kprobe(struct kprobe *p)
911{
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900912 arch_remove_kprobe(p);
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500913 kfree(p);
914}
915
916static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
917{
918 return kzalloc(sizeof(struct kprobe), GFP_KERNEL);
919}
920#endif /* CONFIG_OPTPROBES */
921
Masami Hiramatsuae6aa162012-06-05 19:28:32 +0900922#ifdef KPROBES_CAN_USE_FTRACE
923static struct ftrace_ops kprobe_ftrace_ops __read_mostly = {
Masami Hiramatsue5253892012-06-05 19:28:38 +0900924 .func = kprobe_ftrace_handler,
Masami Hiramatsuae6aa162012-06-05 19:28:32 +0900925 .flags = FTRACE_OPS_FL_SAVE_REGS,
926};
927static int kprobe_ftrace_enabled;
928
929/* Must ensure p->addr is really on ftrace */
930static int __kprobes prepare_kprobe(struct kprobe *p)
931{
932 if (!kprobe_ftrace(p))
933 return arch_prepare_kprobe(p);
934
935 return arch_prepare_kprobe_ftrace(p);
936}
937
938/* Caller must lock kprobe_mutex */
939static void __kprobes arm_kprobe_ftrace(struct kprobe *p)
940{
941 int ret;
942
943 ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
944 (unsigned long)p->addr, 0, 0);
945 WARN(ret < 0, "Failed to arm kprobe-ftrace at %p (%d)\n", p->addr, ret);
946 kprobe_ftrace_enabled++;
947 if (kprobe_ftrace_enabled == 1) {
948 ret = register_ftrace_function(&kprobe_ftrace_ops);
949 WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret);
950 }
951}
952
953/* Caller must lock kprobe_mutex */
954static void __kprobes disarm_kprobe_ftrace(struct kprobe *p)
955{
956 int ret;
957
958 kprobe_ftrace_enabled--;
959 if (kprobe_ftrace_enabled == 0) {
960 ret = unregister_ftrace_function(&kprobe_ftrace_ops);
961 WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret);
962 }
963 ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
964 (unsigned long)p->addr, 1, 0);
965 WARN(ret < 0, "Failed to disarm kprobe-ftrace at %p (%d)\n", p->addr, ret);
966}
967#else /* !KPROBES_CAN_USE_FTRACE */
968#define prepare_kprobe(p) arch_prepare_kprobe(p)
969#define arm_kprobe_ftrace(p) do {} while (0)
970#define disarm_kprobe_ftrace(p) do {} while (0)
971#endif
972
Masami Hiramatsu201517a2009-05-07 16:31:26 -0400973/* Arm a kprobe with text_mutex */
974static void __kprobes arm_kprobe(struct kprobe *kp)
975{
Masami Hiramatsuae6aa162012-06-05 19:28:32 +0900976 if (unlikely(kprobe_ftrace(kp))) {
977 arm_kprobe_ftrace(kp);
978 return;
979 }
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500980 /*
981 * Here, since __arm_kprobe() doesn't use stop_machine(),
982 * this doesn't cause deadlock on text_mutex. So, we don't
983 * need get_online_cpus().
984 */
Masami Hiramatsu201517a2009-05-07 16:31:26 -0400985 mutex_lock(&text_mutex);
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500986 __arm_kprobe(kp);
Masami Hiramatsu201517a2009-05-07 16:31:26 -0400987 mutex_unlock(&text_mutex);
988}
989
990/* Disarm a kprobe with text_mutex */
Masami Hiramatsuae6aa162012-06-05 19:28:32 +0900991static void __kprobes disarm_kprobe(struct kprobe *kp, bool reopt)
Masami Hiramatsu201517a2009-05-07 16:31:26 -0400992{
Masami Hiramatsuae6aa162012-06-05 19:28:32 +0900993 if (unlikely(kprobe_ftrace(kp))) {
994 disarm_kprobe_ftrace(kp);
995 return;
996 }
Masami Hiramatsu6274de42010-12-03 18:54:09 +0900997 /* Ditto */
Masami Hiramatsu201517a2009-05-07 16:31:26 -0400998 mutex_lock(&text_mutex);
Masami Hiramatsuae6aa162012-06-05 19:28:32 +0900999 __disarm_kprobe(kp, reopt);
Masami Hiramatsu201517a2009-05-07 16:31:26 -04001000 mutex_unlock(&text_mutex);
1001}
1002
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001003/*
1004 * Aggregate handlers for multiple kprobes support - these handlers
1005 * take care of invoking the individual kprobe handlers on p->list
1006 */
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -07001007static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001008{
1009 struct kprobe *kp;
1010
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -08001011 list_for_each_entry_rcu(kp, &p->list, list) {
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001012 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -08001013 set_kprobe_instance(kp);
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -07001014 if (kp->pre_handler(kp, regs))
1015 return 1;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001016 }
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -08001017 reset_kprobe_instance();
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001018 }
1019 return 0;
1020}
1021
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -07001022static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
1023 unsigned long flags)
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001024{
1025 struct kprobe *kp;
1026
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -08001027 list_for_each_entry_rcu(kp, &p->list, list) {
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001028 if (kp->post_handler && likely(!kprobe_disabled(kp))) {
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -08001029 set_kprobe_instance(kp);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001030 kp->post_handler(kp, regs, flags);
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -08001031 reset_kprobe_instance();
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001032 }
1033 }
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001034}
1035
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -07001036static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
1037 int trapnr)
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001038{
Christoph Lameterb76834b2010-12-06 11:16:25 -06001039 struct kprobe *cur = __this_cpu_read(kprobe_instance);
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -08001040
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001041 /*
1042 * if we faulted "during" the execution of a user specified
1043 * probe handler, invoke just that probe's fault handler
1044 */
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -08001045 if (cur && cur->fault_handler) {
1046 if (cur->fault_handler(cur, regs, trapnr))
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001047 return 1;
1048 }
1049 return 0;
1050}
1051
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -07001052static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -07001053{
Christoph Lameterb76834b2010-12-06 11:16:25 -06001054 struct kprobe *cur = __this_cpu_read(kprobe_instance);
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -08001055 int ret = 0;
1056
1057 if (cur && cur->break_handler) {
1058 if (cur->break_handler(cur, regs))
1059 ret = 1;
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -07001060 }
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -08001061 reset_kprobe_instance();
1062 return ret;
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -07001063}
1064
Keshavamurthy Anil Sbf8d5c52005-12-12 00:37:34 -08001065/* Walks the list and increments nmissed count for multiprobe case */
1066void __kprobes kprobes_inc_nmissed_count(struct kprobe *p)
1067{
1068 struct kprobe *kp;
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001069 if (!kprobe_aggrprobe(p)) {
Keshavamurthy Anil Sbf8d5c52005-12-12 00:37:34 -08001070 p->nmissed++;
1071 } else {
1072 list_for_each_entry_rcu(kp, &p->list, list)
1073 kp->nmissed++;
1074 }
1075 return;
1076}
1077
bibo,mao99219a32006-10-02 02:17:35 -07001078void __kprobes recycle_rp_inst(struct kretprobe_instance *ri,
1079 struct hlist_head *head)
Hien Nguyenb94cce92005-06-23 00:09:19 -07001080{
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001081 struct kretprobe *rp = ri->rp;
1082
Hien Nguyenb94cce92005-06-23 00:09:19 -07001083 /* remove rp inst off the rprobe_inst_table */
1084 hlist_del(&ri->hlist);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001085 INIT_HLIST_NODE(&ri->hlist);
1086 if (likely(rp)) {
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001087 raw_spin_lock(&rp->lock);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001088 hlist_add_head(&ri->hlist, &rp->free_instances);
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001089 raw_spin_unlock(&rp->lock);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001090 } else
1091 /* Unregistering */
bibo,mao99219a32006-10-02 02:17:35 -07001092 hlist_add_head(&ri->hlist, head);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001093}
1094
Masami Hiramatsu017c39b2009-01-06 14:41:51 -08001095void __kprobes kretprobe_hash_lock(struct task_struct *tsk,
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001096 struct hlist_head **head, unsigned long *flags)
Namhyung Kim635c17c2010-09-15 10:04:30 +09001097__acquires(hlist_lock)
Hien Nguyenb94cce92005-06-23 00:09:19 -07001098{
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001099 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001100 raw_spinlock_t *hlist_lock;
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001101
1102 *head = &kretprobe_inst_table[hash];
1103 hlist_lock = kretprobe_table_lock_ptr(hash);
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001104 raw_spin_lock_irqsave(hlist_lock, *flags);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001105}
1106
Masami Hiramatsu017c39b2009-01-06 14:41:51 -08001107static void __kprobes 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}
1114
Masami Hiramatsu017c39b2009-01-06 14:41:51 -08001115void __kprobes kretprobe_hash_unlock(struct task_struct *tsk,
1116 unsigned long *flags)
Namhyung Kim635c17c2010-09-15 10:04:30 +09001117__releases(hlist_lock)
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001118{
1119 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001120 raw_spinlock_t *hlist_lock;
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001121
1122 hlist_lock = kretprobe_table_lock_ptr(hash);
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001123 raw_spin_unlock_irqrestore(hlist_lock, *flags);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001124}
1125
Namhyung Kim6376b222010-09-15 10:04:28 +09001126static void __kprobes kretprobe_table_unlock(unsigned long hash,
1127 unsigned long *flags)
Namhyung Kim635c17c2010-09-15 10:04:30 +09001128__releases(hlist_lock)
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001129{
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001130 raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
1131 raw_spin_unlock_irqrestore(hlist_lock, *flags);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001132}
1133
Hien Nguyenb94cce92005-06-23 00:09:19 -07001134/*
bibo maoc6fd91f2006-03-26 01:38:20 -08001135 * This function is called from finish_task_switch when task tk becomes dead,
1136 * so that we can recycle any function-return probe instances associated
1137 * with this task. These left over instances represent probed functions
1138 * that have been called but will never return.
Hien Nguyenb94cce92005-06-23 00:09:19 -07001139 */
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -07001140void __kprobes kprobe_flush_task(struct task_struct *tk)
Hien Nguyenb94cce92005-06-23 00:09:19 -07001141{
bibo,mao62c27be2006-10-02 02:17:33 -07001142 struct kretprobe_instance *ri;
bibo,mao99219a32006-10-02 02:17:35 -07001143 struct hlist_head *head, empty_rp;
Rusty Lynch802eae72005-06-27 15:17:08 -07001144 struct hlist_node *node, *tmp;
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001145 unsigned long hash, flags = 0;
Rusty Lynch802eae72005-06-27 15:17:08 -07001146
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001147 if (unlikely(!kprobes_initialized))
1148 /* Early boot. kretprobe_table_locks not yet initialized. */
1149 return;
1150
Ananth N Mavinakayanahallid496aab2012-01-20 14:34:04 -08001151 INIT_HLIST_HEAD(&empty_rp);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001152 hash = hash_ptr(tk, KPROBE_HASH_BITS);
1153 head = &kretprobe_inst_table[hash];
1154 kretprobe_table_lock(hash, &flags);
bibo,mao62c27be2006-10-02 02:17:33 -07001155 hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
1156 if (ri->task == tk)
bibo,mao99219a32006-10-02 02:17:35 -07001157 recycle_rp_inst(ri, &empty_rp);
bibo,mao62c27be2006-10-02 02:17:33 -07001158 }
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001159 kretprobe_table_unlock(hash, &flags);
bibo,mao99219a32006-10-02 02:17:35 -07001160 hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
1161 hlist_del(&ri->hlist);
1162 kfree(ri);
1163 }
Hien Nguyenb94cce92005-06-23 00:09:19 -07001164}
1165
Hien Nguyenb94cce92005-06-23 00:09:19 -07001166static inline void free_rp_inst(struct kretprobe *rp)
1167{
1168 struct kretprobe_instance *ri;
Christoph Hellwig4c4308c2007-05-08 00:34:14 -07001169 struct hlist_node *pos, *next;
1170
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001171 hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) {
1172 hlist_del(&ri->hlist);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001173 kfree(ri);
1174 }
1175}
1176
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001177static void __kprobes cleanup_rp_inst(struct kretprobe *rp)
1178{
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001179 unsigned long flags, hash;
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001180 struct kretprobe_instance *ri;
1181 struct hlist_node *pos, *next;
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001182 struct hlist_head *head;
1183
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001184 /* No race here */
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001185 for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) {
1186 kretprobe_table_lock(hash, &flags);
1187 head = &kretprobe_inst_table[hash];
1188 hlist_for_each_entry_safe(ri, pos, next, head, hlist) {
1189 if (ri->rp == rp)
1190 ri->rp = NULL;
1191 }
1192 kretprobe_table_unlock(hash, &flags);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001193 }
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001194 free_rp_inst(rp);
1195}
1196
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001197/*
Masami Hiramatsub918e5e2009-04-06 19:00:58 -07001198* Add the new probe to ap->list. Fail if this is the
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -07001199* second jprobe at the address - two jprobes can't coexist
1200*/
Masami Hiramatsub918e5e2009-04-06 19:00:58 -07001201static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p)
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -07001202{
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001203 BUG_ON(kprobe_gone(ap) || kprobe_gone(p));
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001204
1205 if (p->break_handler || p->post_handler)
Masami Hiramatsu6274de42010-12-03 18:54:09 +09001206 unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001207
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -07001208 if (p->break_handler) {
Masami Hiramatsub918e5e2009-04-06 19:00:58 -07001209 if (ap->break_handler)
mao, bibo36721652006-06-26 00:25:22 -07001210 return -EEXIST;
Masami Hiramatsub918e5e2009-04-06 19:00:58 -07001211 list_add_tail_rcu(&p->list, &ap->list);
1212 ap->break_handler = aggr_break_handler;
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -07001213 } else
Masami Hiramatsub918e5e2009-04-06 19:00:58 -07001214 list_add_rcu(&p->list, &ap->list);
1215 if (p->post_handler && !ap->post_handler)
1216 ap->post_handler = aggr_post_handler;
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001217
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -07001218 return 0;
1219}
1220
1221/*
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001222 * Fill in the required fields of the "manager kprobe". Replace the
1223 * earlier kprobe in the hlist with the manager kprobe
1224 */
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001225static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001226{
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001227 /* Copy p's insn slot to ap */
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -07001228 copy_kprobe(p, ap);
bibo, maoa9ad9652006-07-30 03:03:26 -07001229 flush_insn_slot(ap);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001230 ap->addr = p->addr;
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001231 ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001232 ap->pre_handler = aggr_pre_handler;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001233 ap->fault_handler = aggr_fault_handler;
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001234 /* We don't care the kprobe which has gone. */
1235 if (p->post_handler && !kprobe_gone(p))
mao, bibo36721652006-06-26 00:25:22 -07001236 ap->post_handler = aggr_post_handler;
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001237 if (p->break_handler && !kprobe_gone(p))
mao, bibo36721652006-06-26 00:25:22 -07001238 ap->break_handler = aggr_break_handler;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001239
1240 INIT_LIST_HEAD(&ap->list);
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001241 INIT_HLIST_NODE(&ap->hlist);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001242
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001243 list_add_rcu(&p->list, &ap->list);
Keshavamurthy Anil Sadad0f32005-12-12 00:37:12 -08001244 hlist_replace_rcu(&p->hlist, &ap->hlist);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001245}
1246
1247/*
1248 * This is the second or subsequent kprobe at the address - handle
1249 * the intricacies
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001250 */
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001251static int __kprobes register_aggr_kprobe(struct kprobe *orig_p,
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -07001252 struct kprobe *p)
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001253{
1254 int ret = 0;
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001255 struct kprobe *ap = orig_p;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001256
Masami Hiramatsu25764282012-06-05 19:28:26 +09001257 /* For preparing optimization, jump_label_text_reserved() is called */
1258 jump_label_lock();
1259 /*
1260 * Get online CPUs to avoid text_mutex deadlock.with stop machine,
1261 * which is invoked by unoptimize_kprobe() in add_new_kprobe()
1262 */
1263 get_online_cpus();
1264 mutex_lock(&text_mutex);
1265
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001266 if (!kprobe_aggrprobe(orig_p)) {
1267 /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */
1268 ap = alloc_aggr_kprobe(orig_p);
Masami Hiramatsu25764282012-06-05 19:28:26 +09001269 if (!ap) {
1270 ret = -ENOMEM;
1271 goto out;
1272 }
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001273 init_aggr_kprobe(ap, orig_p);
Masami Hiramatsu6274de42010-12-03 18:54:09 +09001274 } else if (kprobe_unused(ap))
Masami Hiramatsu0490cd12010-12-03 18:54:16 +09001275 /* This probe is going to die. Rescue it */
1276 reuse_unused_kprobe(ap);
Masami Hiramatsub918e5e2009-04-06 19:00:58 -07001277
1278 if (kprobe_gone(ap)) {
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001279 /*
1280 * Attempting to insert new probe at the same location that
1281 * had a probe in the module vaddr area which already
1282 * freed. So, the instruction slot has already been
1283 * released. We need a new slot for the new probe.
1284 */
Masami Hiramatsub918e5e2009-04-06 19:00:58 -07001285 ret = arch_prepare_kprobe(ap);
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001286 if (ret)
Masami Hiramatsub918e5e2009-04-06 19:00:58 -07001287 /*
1288 * Even if fail to allocate new slot, don't need to
1289 * free aggr_probe. It will be used next time, or
1290 * freed by unregister_kprobe.
1291 */
Masami Hiramatsu25764282012-06-05 19:28:26 +09001292 goto out;
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001293
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001294 /* Prepare optimized instructions if possible. */
1295 prepare_optimized_kprobe(ap);
1296
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001297 /*
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001298 * Clear gone flag to prevent allocating new slot again, and
1299 * set disabled flag because it is not armed yet.
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001300 */
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001301 ap->flags = (ap->flags & ~KPROBE_FLAG_GONE)
1302 | KPROBE_FLAG_DISABLED;
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001303 }
Masami Hiramatsub918e5e2009-04-06 19:00:58 -07001304
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001305 /* Copy ap's insn slot to p */
Masami Hiramatsub918e5e2009-04-06 19:00:58 -07001306 copy_kprobe(ap, p);
Masami Hiramatsu25764282012-06-05 19:28:26 +09001307 ret = add_new_kprobe(ap, p);
1308
1309out:
1310 mutex_unlock(&text_mutex);
1311 put_online_cpus();
1312 jump_label_unlock();
1313
1314 if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) {
1315 ap->flags &= ~KPROBE_FLAG_DISABLED;
1316 if (!kprobes_all_disarmed)
1317 /* Arm the breakpoint again. */
1318 arm_kprobe(ap);
1319 }
1320 return ret;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001321}
1322
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -07001323static int __kprobes in_kprobes_functions(unsigned long addr)
1324{
Srinivasa Ds3d8d9962008-04-28 02:14:26 -07001325 struct kprobe_blackpoint *kb;
1326
Christoph Hellwig6f716ac2007-05-08 00:34:13 -07001327 if (addr >= (unsigned long)__kprobes_text_start &&
1328 addr < (unsigned long)__kprobes_text_end)
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -07001329 return -EINVAL;
Srinivasa Ds3d8d9962008-04-28 02:14:26 -07001330 /*
1331 * If there exists a kprobe_blacklist, verify and
1332 * fail any probe registration in the prohibited area
1333 */
1334 for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
1335 if (kb->start_addr) {
1336 if (addr >= kb->start_addr &&
1337 addr < (kb->start_addr + kb->range))
1338 return -EINVAL;
1339 }
1340 }
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -07001341 return 0;
1342}
1343
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001344/*
1345 * If we have a symbol_name argument, look it up and add the offset field
1346 * to it. This way, we can specify a relative address to a symbol.
Masami Hiramatsubc81d482011-06-27 16:26:50 +09001347 * This returns encoded errors if it fails to look up symbol or invalid
1348 * combination of parameters.
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001349 */
1350static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p)
1351{
1352 kprobe_opcode_t *addr = p->addr;
Masami Hiramatsubc81d482011-06-27 16:26:50 +09001353
1354 if ((p->symbol_name && p->addr) ||
1355 (!p->symbol_name && !p->addr))
1356 goto invalid;
1357
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001358 if (p->symbol_name) {
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001359 kprobe_lookup_name(p->symbol_name, addr);
Masami Hiramatsubc81d482011-06-27 16:26:50 +09001360 if (!addr)
1361 return ERR_PTR(-ENOENT);
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001362 }
1363
Masami Hiramatsubc81d482011-06-27 16:26:50 +09001364 addr = (kprobe_opcode_t *)(((char *)addr) + p->offset);
1365 if (addr)
1366 return addr;
1367
1368invalid:
1369 return ERR_PTR(-EINVAL);
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001370}
1371
Ananth N Mavinakayanahalli1f0ab402009-09-15 10:43:07 +05301372/* Check passed kprobe is valid and return kprobe in kprobe_table. */
1373static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p)
1374{
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001375 struct kprobe *ap, *list_p;
Ananth N Mavinakayanahalli1f0ab402009-09-15 10:43:07 +05301376
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001377 ap = get_kprobe(p->addr);
1378 if (unlikely(!ap))
Ananth N Mavinakayanahalli1f0ab402009-09-15 10:43:07 +05301379 return NULL;
1380
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001381 if (p != ap) {
1382 list_for_each_entry_rcu(list_p, &ap->list, list)
Ananth N Mavinakayanahalli1f0ab402009-09-15 10:43:07 +05301383 if (list_p == p)
1384 /* kprobe p is a valid probe */
1385 goto valid;
1386 return NULL;
1387 }
1388valid:
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001389 return ap;
Ananth N Mavinakayanahalli1f0ab402009-09-15 10:43:07 +05301390}
1391
1392/* Return error if the kprobe is being re-registered */
1393static inline int check_kprobe_rereg(struct kprobe *p)
1394{
1395 int ret = 0;
Ananth N Mavinakayanahalli1f0ab402009-09-15 10:43:07 +05301396
1397 mutex_lock(&kprobe_mutex);
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001398 if (__get_valid_kprobe(p))
Ananth N Mavinakayanahalli1f0ab402009-09-15 10:43:07 +05301399 ret = -EINVAL;
1400 mutex_unlock(&kprobe_mutex);
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001401
Ananth N Mavinakayanahalli1f0ab402009-09-15 10:43:07 +05301402 return ret;
1403}
1404
Masami Hiramatsuf7fa6ef02012-06-05 19:28:20 +09001405static __kprobes int check_kprobe_address_safe(struct kprobe *p,
1406 struct module **probed_mod)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001407{
1408 int ret = 0;
Masami Hiramatsuae6aa162012-06-05 19:28:32 +09001409 unsigned long ftrace_addr;
1410
1411 /*
1412 * If the address is located on a ftrace nop, set the
1413 * breakpoint to the following instruction.
1414 */
1415 ftrace_addr = ftrace_location((unsigned long)p->addr);
1416 if (ftrace_addr) {
1417#ifdef KPROBES_CAN_USE_FTRACE
1418 /* Given address is not on the instruction boundary */
1419 if ((unsigned long)p->addr != ftrace_addr)
1420 return -EILSEQ;
Masami Hiramatsuae6aa162012-06-05 19:28:32 +09001421 p->flags |= KPROBE_FLAG_FTRACE;
1422#else /* !KPROBES_CAN_USE_FTRACE */
1423 return -EINVAL;
1424#endif
1425 }
Masami Hiramatsuf7fa6ef02012-06-05 19:28:20 +09001426
1427 jump_label_lock();
1428 preempt_disable();
1429
1430 /* Ensure it is not in reserved area nor out of text */
1431 if (!kernel_text_address((unsigned long) p->addr) ||
1432 in_kprobes_functions((unsigned long) p->addr) ||
Masami Hiramatsuf7fa6ef02012-06-05 19:28:20 +09001433 jump_label_text_reserved(p->addr, p->addr)) {
1434 ret = -EINVAL;
1435 goto out;
1436 }
1437
1438 /* Check if are we probing a module */
1439 *probed_mod = __module_text_address((unsigned long) p->addr);
1440 if (*probed_mod) {
1441 /*
1442 * We must hold a refcount of the probed module while updating
1443 * its code to prohibit unexpected unloading.
1444 */
1445 if (unlikely(!try_module_get(*probed_mod))) {
1446 ret = -ENOENT;
1447 goto out;
1448 }
1449
1450 /*
1451 * If the module freed .init.text, we couldn't insert
1452 * kprobes in there.
1453 */
1454 if (within_module_init((unsigned long)p->addr, *probed_mod) &&
1455 (*probed_mod)->state != MODULE_STATE_COMING) {
1456 module_put(*probed_mod);
1457 *probed_mod = NULL;
1458 ret = -ENOENT;
1459 }
1460 }
1461out:
1462 preempt_enable();
1463 jump_label_unlock();
1464
1465 return ret;
1466}
1467
1468int __kprobes register_kprobe(struct kprobe *p)
1469{
1470 int ret;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001471 struct kprobe *old_p;
Keshavamurthy Anil Sdf019b12006-01-11 12:17:41 -08001472 struct module *probed_mod;
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001473 kprobe_opcode_t *addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001474
Masami Hiramatsuf7fa6ef02012-06-05 19:28:20 +09001475 /* Adjust probe address from symbol */
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001476 addr = kprobe_addr(p);
Masami Hiramatsubc81d482011-06-27 16:26:50 +09001477 if (IS_ERR(addr))
1478 return PTR_ERR(addr);
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001479 p->addr = addr;
Ananth N Mavinakayanahalli3a872d82006-10-02 02:17:30 -07001480
Ananth N Mavinakayanahalli1f0ab402009-09-15 10:43:07 +05301481 ret = check_kprobe_rereg(p);
1482 if (ret)
1483 return ret;
1484
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001485 /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
1486 p->flags &= KPROBE_FLAG_DISABLED;
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -08001487 p->nmissed = 0;
Masami Hiramatsu98616682008-04-28 02:14:28 -07001488 INIT_LIST_HEAD(&p->list);
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001489
Masami Hiramatsuf7fa6ef02012-06-05 19:28:20 +09001490 ret = check_kprobe_address_safe(p, &probed_mod);
1491 if (ret)
1492 return ret;
1493
1494 mutex_lock(&kprobe_mutex);
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001495
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001496 old_p = get_kprobe(p->addr);
1497 if (old_p) {
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001498 /* Since this may unoptimize old_p, locking text_mutex. */
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001499 ret = register_aggr_kprobe(old_p, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001500 goto out;
1501 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001502
Masami Hiramatsu25764282012-06-05 19:28:26 +09001503 mutex_lock(&text_mutex); /* Avoiding text modification */
Masami Hiramatsuae6aa162012-06-05 19:28:32 +09001504 ret = prepare_kprobe(p);
Masami Hiramatsu25764282012-06-05 19:28:26 +09001505 mutex_unlock(&text_mutex);
Christoph Hellwig6f716ac2007-05-08 00:34:13 -07001506 if (ret)
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001507 goto out;
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -08001508
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001509 INIT_HLIST_NODE(&p->hlist);
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -08001510 hlist_add_head_rcu(&p->hlist,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001511 &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
1512
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001513 if (!kprobes_all_disarmed && !kprobe_disabled(p))
Masami Hiramatsu25764282012-06-05 19:28:26 +09001514 arm_kprobe(p);
Christoph Hellwig74a0b572007-10-16 01:24:07 -07001515
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001516 /* Try to optimize kprobe */
1517 try_to_optimize_kprobe(p);
1518
Linus Torvalds1da177e2005-04-16 15:20:36 -07001519out:
Ingo Molnar7a7d1cf2006-03-23 03:00:35 -08001520 mutex_unlock(&kprobe_mutex);
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -08001521
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001522 if (probed_mod)
Keshavamurthy Anil Sdf019b12006-01-11 12:17:41 -08001523 module_put(probed_mod);
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001524
Linus Torvalds1da177e2005-04-16 15:20:36 -07001525 return ret;
1526}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001527EXPORT_SYMBOL_GPL(register_kprobe);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001528
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001529/* Check if all probes on the aggrprobe are disabled */
1530static int __kprobes aggr_kprobe_disabled(struct kprobe *ap)
1531{
1532 struct kprobe *kp;
1533
1534 list_for_each_entry_rcu(kp, &ap->list, list)
1535 if (!kprobe_disabled(kp))
1536 /*
1537 * There is an active probe on the list.
1538 * We can't disable this ap.
1539 */
1540 return 0;
1541
1542 return 1;
1543}
1544
1545/* Disable one kprobe: Make sure called under kprobe_mutex is locked */
1546static struct kprobe *__kprobes __disable_kprobe(struct kprobe *p)
1547{
1548 struct kprobe *orig_p;
1549
1550 /* Get an original kprobe for return */
1551 orig_p = __get_valid_kprobe(p);
1552 if (unlikely(orig_p == NULL))
1553 return NULL;
1554
1555 if (!kprobe_disabled(p)) {
1556 /* Disable probe if it is a child probe */
1557 if (p != orig_p)
1558 p->flags |= KPROBE_FLAG_DISABLED;
1559
1560 /* Try to disarm and disable this/parent probe */
1561 if (p == orig_p || aggr_kprobe_disabled(orig_p)) {
Masami Hiramatsuae6aa162012-06-05 19:28:32 +09001562 disarm_kprobe(orig_p, true);
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001563 orig_p->flags |= KPROBE_FLAG_DISABLED;
1564 }
1565 }
1566
1567 return orig_p;
1568}
1569
Masami Hiramatsu98616682008-04-28 02:14:28 -07001570/*
1571 * Unregister a kprobe without a scheduler synchronization.
1572 */
1573static int __kprobes __unregister_kprobe_top(struct kprobe *p)
Keshavamurthy Anil Sdf019b12006-01-11 12:17:41 -08001574{
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001575 struct kprobe *ap, *list_p;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -07001576
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001577 /* Disable kprobe. This will disarm it if needed. */
1578 ap = __disable_kprobe(p);
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001579 if (ap == NULL)
Masami Hiramatsu98616682008-04-28 02:14:28 -07001580 return -EINVAL;
1581
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001582 if (ap == p)
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001583 /*
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001584 * This probe is an independent(and non-optimized) kprobe
1585 * (not an aggrprobe). Remove from the hash list.
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001586 */
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001587 goto disarmed;
1588
1589 /* Following process expects this probe is an aggrprobe */
1590 WARN_ON(!kprobe_aggrprobe(ap));
1591
Masami Hiramatsu6274de42010-12-03 18:54:09 +09001592 if (list_is_singular(&ap->list) && kprobe_disarmed(ap))
1593 /*
1594 * !disarmed could be happen if the probe is under delayed
1595 * unoptimizing.
1596 */
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001597 goto disarmed;
1598 else {
1599 /* If disabling probe has special handlers, update aggrprobe */
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001600 if (p->break_handler && !kprobe_gone(p))
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001601 ap->break_handler = NULL;
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001602 if (p->post_handler && !kprobe_gone(p)) {
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001603 list_for_each_entry_rcu(list_p, &ap->list, list) {
Masami Hiramatsu98616682008-04-28 02:14:28 -07001604 if ((list_p != p) && (list_p->post_handler))
1605 goto noclean;
1606 }
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001607 ap->post_handler = NULL;
Masami Hiramatsu98616682008-04-28 02:14:28 -07001608 }
1609noclean:
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001610 /*
1611 * Remove from the aggrprobe: this path will do nothing in
1612 * __unregister_kprobe_bottom().
1613 */
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -08001614 list_del_rcu(&p->list);
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001615 if (!kprobe_disabled(ap) && !kprobes_all_disarmed)
1616 /*
1617 * Try to optimize this probe again, because post
1618 * handler may have been changed.
1619 */
1620 optimize_kprobe(ap);
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -08001621 }
Masami Hiramatsu98616682008-04-28 02:14:28 -07001622 return 0;
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001623
1624disarmed:
Masami Hiramatsu6274de42010-12-03 18:54:09 +09001625 BUG_ON(!kprobe_disarmed(ap));
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001626 hlist_del_rcu(&ap->hlist);
1627 return 0;
Masami Hiramatsu98616682008-04-28 02:14:28 -07001628}
Mao, Bibob3e55c72005-12-12 00:37:00 -08001629
Masami Hiramatsu98616682008-04-28 02:14:28 -07001630static void __kprobes __unregister_kprobe_bottom(struct kprobe *p)
1631{
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001632 struct kprobe *ap;
Mao, Bibob3e55c72005-12-12 00:37:00 -08001633
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001634 if (list_empty(&p->list))
Masami Hiramatsu6274de42010-12-03 18:54:09 +09001635 /* This is an independent kprobe */
Ananth N Mavinakayanahalli0498b632006-01-09 20:52:46 -08001636 arch_remove_kprobe(p);
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001637 else if (list_is_singular(&p->list)) {
Masami Hiramatsu6274de42010-12-03 18:54:09 +09001638 /* This is the last child of an aggrprobe */
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001639 ap = list_entry(p->list.next, struct kprobe, list);
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001640 list_del(&p->list);
Masami Hiramatsu6d8e40a2010-12-03 18:53:50 +09001641 free_aggr_kprobe(ap);
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -08001642 }
Masami Hiramatsu6274de42010-12-03 18:54:09 +09001643 /* Otherwise, do nothing. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001644}
1645
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -08001646int __kprobes register_kprobes(struct kprobe **kps, int num)
Masami Hiramatsu98616682008-04-28 02:14:28 -07001647{
1648 int i, ret = 0;
1649
1650 if (num <= 0)
1651 return -EINVAL;
1652 for (i = 0; i < num; i++) {
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -08001653 ret = register_kprobe(kps[i]);
Masami Hiramatsu67dddaa2008-06-12 15:21:35 -07001654 if (ret < 0) {
1655 if (i > 0)
1656 unregister_kprobes(kps, i);
Masami Hiramatsu98616682008-04-28 02:14:28 -07001657 break;
1658 }
1659 }
1660 return ret;
1661}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001662EXPORT_SYMBOL_GPL(register_kprobes);
Masami Hiramatsu98616682008-04-28 02:14:28 -07001663
Masami Hiramatsu98616682008-04-28 02:14:28 -07001664void __kprobes unregister_kprobe(struct kprobe *p)
1665{
1666 unregister_kprobes(&p, 1);
1667}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001668EXPORT_SYMBOL_GPL(unregister_kprobe);
Masami Hiramatsu98616682008-04-28 02:14:28 -07001669
Masami Hiramatsu98616682008-04-28 02:14:28 -07001670void __kprobes unregister_kprobes(struct kprobe **kps, int num)
1671{
1672 int i;
1673
1674 if (num <= 0)
1675 return;
1676 mutex_lock(&kprobe_mutex);
1677 for (i = 0; i < num; i++)
1678 if (__unregister_kprobe_top(kps[i]) < 0)
1679 kps[i]->addr = NULL;
1680 mutex_unlock(&kprobe_mutex);
1681
1682 synchronize_sched();
1683 for (i = 0; i < num; i++)
1684 if (kps[i]->addr)
1685 __unregister_kprobe_bottom(kps[i]);
1686}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001687EXPORT_SYMBOL_GPL(unregister_kprobes);
Masami Hiramatsu98616682008-04-28 02:14:28 -07001688
Linus Torvalds1da177e2005-04-16 15:20:36 -07001689static struct notifier_block kprobe_exceptions_nb = {
1690 .notifier_call = kprobe_exceptions_notify,
Anil S Keshavamurthy3d5631e2006-06-26 00:25:28 -07001691 .priority = 0x7fffffff /* we need to be notified first */
1692};
1693
Michael Ellerman3d7e3382007-07-19 01:48:11 -07001694unsigned long __weak arch_deref_entry_point(void *entry)
1695{
1696 return (unsigned long)entry;
1697}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001698
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -08001699int __kprobes register_jprobes(struct jprobe **jps, int num)
Masami Hiramatsu26b31c12008-04-28 02:14:29 -07001700{
1701 struct jprobe *jp;
1702 int ret = 0, i;
1703
1704 if (num <= 0)
1705 return -EINVAL;
1706 for (i = 0; i < num; i++) {
Namhyung Kim05662bd2010-09-15 10:04:27 +09001707 unsigned long addr, offset;
Masami Hiramatsu26b31c12008-04-28 02:14:29 -07001708 jp = jps[i];
1709 addr = arch_deref_entry_point(jp->entry);
1710
Namhyung Kim05662bd2010-09-15 10:04:27 +09001711 /* Verify probepoint is a function entry point */
1712 if (kallsyms_lookup_size_offset(addr, NULL, &offset) &&
1713 offset == 0) {
1714 jp->kp.pre_handler = setjmp_pre_handler;
1715 jp->kp.break_handler = longjmp_break_handler;
1716 ret = register_kprobe(&jp->kp);
1717 } else
1718 ret = -EINVAL;
Namhyung Kimedbaadb2010-09-15 10:04:26 +09001719
Masami Hiramatsu67dddaa2008-06-12 15:21:35 -07001720 if (ret < 0) {
1721 if (i > 0)
1722 unregister_jprobes(jps, i);
Masami Hiramatsu26b31c12008-04-28 02:14:29 -07001723 break;
1724 }
1725 }
1726 return ret;
1727}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001728EXPORT_SYMBOL_GPL(register_jprobes);
Masami Hiramatsu26b31c12008-04-28 02:14:29 -07001729
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -07001730int __kprobes register_jprobe(struct jprobe *jp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001731{
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -08001732 return register_jprobes(&jp, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001733}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001734EXPORT_SYMBOL_GPL(register_jprobe);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001735
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -07001736void __kprobes unregister_jprobe(struct jprobe *jp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001737{
Masami Hiramatsu26b31c12008-04-28 02:14:29 -07001738 unregister_jprobes(&jp, 1);
1739}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001740EXPORT_SYMBOL_GPL(unregister_jprobe);
Masami Hiramatsu26b31c12008-04-28 02:14:29 -07001741
Masami Hiramatsu26b31c12008-04-28 02:14:29 -07001742void __kprobes unregister_jprobes(struct jprobe **jps, int num)
1743{
1744 int i;
1745
1746 if (num <= 0)
1747 return;
1748 mutex_lock(&kprobe_mutex);
1749 for (i = 0; i < num; i++)
1750 if (__unregister_kprobe_top(&jps[i]->kp) < 0)
1751 jps[i]->kp.addr = NULL;
1752 mutex_unlock(&kprobe_mutex);
1753
1754 synchronize_sched();
1755 for (i = 0; i < num; i++) {
1756 if (jps[i]->kp.addr)
1757 __unregister_kprobe_bottom(&jps[i]->kp);
1758 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001759}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001760EXPORT_SYMBOL_GPL(unregister_jprobes);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001761
Ananth N Mavinakayanahalli9edddaa2008-03-04 14:28:37 -08001762#ifdef CONFIG_KRETPROBES
Adrian Bunke65cefe2006-02-03 03:03:42 -08001763/*
1764 * This kprobe pre_handler is registered with every kretprobe. When probe
1765 * hits it will set up the return probe.
1766 */
1767static int __kprobes pre_handler_kretprobe(struct kprobe *p,
1768 struct pt_regs *regs)
1769{
1770 struct kretprobe *rp = container_of(p, struct kretprobe, kp);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001771 unsigned long hash, flags = 0;
1772 struct kretprobe_instance *ri;
Adrian Bunke65cefe2006-02-03 03:03:42 -08001773
1774 /*TODO: consider to only swap the RA after the last pre_handler fired */
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001775 hash = hash_ptr(current, KPROBE_HASH_BITS);
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001776 raw_spin_lock_irqsave(&rp->lock, flags);
Christoph Hellwig4c4308c2007-05-08 00:34:14 -07001777 if (!hlist_empty(&rp->free_instances)) {
Christoph Hellwig4c4308c2007-05-08 00:34:14 -07001778 ri = hlist_entry(rp->free_instances.first,
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001779 struct kretprobe_instance, hlist);
1780 hlist_del(&ri->hlist);
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001781 raw_spin_unlock_irqrestore(&rp->lock, flags);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001782
Christoph Hellwig4c4308c2007-05-08 00:34:14 -07001783 ri->rp = rp;
1784 ri->task = current;
Abhishek Sagarf47cd9b2008-02-06 01:38:22 -08001785
Jiang Liu55ca6142012-02-03 15:37:16 -08001786 if (rp->entry_handler && rp->entry_handler(ri, regs)) {
1787 raw_spin_lock_irqsave(&rp->lock, flags);
1788 hlist_add_head(&ri->hlist, &rp->free_instances);
1789 raw_spin_unlock_irqrestore(&rp->lock, flags);
Abhishek Sagarf47cd9b2008-02-06 01:38:22 -08001790 return 0;
Jiang Liu55ca6142012-02-03 15:37:16 -08001791 }
Abhishek Sagarf47cd9b2008-02-06 01:38:22 -08001792
Christoph Hellwig4c4308c2007-05-08 00:34:14 -07001793 arch_prepare_kretprobe(ri, regs);
1794
1795 /* XXX(hch): why is there no hlist_move_head? */
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001796 INIT_HLIST_NODE(&ri->hlist);
1797 kretprobe_table_lock(hash, &flags);
1798 hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]);
1799 kretprobe_table_unlock(hash, &flags);
1800 } else {
Christoph Hellwig4c4308c2007-05-08 00:34:14 -07001801 rp->nmissed++;
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001802 raw_spin_unlock_irqrestore(&rp->lock, flags);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001803 }
Adrian Bunke65cefe2006-02-03 03:03:42 -08001804 return 0;
1805}
1806
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -08001807int __kprobes register_kretprobe(struct kretprobe *rp)
Hien Nguyenb94cce92005-06-23 00:09:19 -07001808{
1809 int ret = 0;
1810 struct kretprobe_instance *inst;
1811 int i;
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001812 void *addr;
Masami Hiramatsuf438d912007-10-16 01:27:49 -07001813
1814 if (kretprobe_blacklist_size) {
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -08001815 addr = kprobe_addr(&rp->kp);
Masami Hiramatsubc81d482011-06-27 16:26:50 +09001816 if (IS_ERR(addr))
1817 return PTR_ERR(addr);
Masami Hiramatsuf438d912007-10-16 01:27:49 -07001818
1819 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
1820 if (kretprobe_blacklist[i].addr == addr)
1821 return -EINVAL;
1822 }
1823 }
Hien Nguyenb94cce92005-06-23 00:09:19 -07001824
1825 rp->kp.pre_handler = pre_handler_kretprobe;
Ananth N Mavinakayanahalli7522a842006-04-20 02:43:11 -07001826 rp->kp.post_handler = NULL;
1827 rp->kp.fault_handler = NULL;
1828 rp->kp.break_handler = NULL;
Hien Nguyenb94cce92005-06-23 00:09:19 -07001829
1830 /* Pre-allocate memory for max kretprobe instances */
1831 if (rp->maxactive <= 0) {
1832#ifdef CONFIG_PREEMPT
Heiko Carstensc2ef6662009-12-21 13:02:24 +01001833 rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());
Hien Nguyenb94cce92005-06-23 00:09:19 -07001834#else
Ananth N Mavinakayanahalli4dae5602009-10-30 19:23:10 +05301835 rp->maxactive = num_possible_cpus();
Hien Nguyenb94cce92005-06-23 00:09:19 -07001836#endif
1837 }
Thomas Gleixnerec4846082009-07-25 16:09:17 +02001838 raw_spin_lock_init(&rp->lock);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001839 INIT_HLIST_HEAD(&rp->free_instances);
1840 for (i = 0; i < rp->maxactive; i++) {
Abhishek Sagarf47cd9b2008-02-06 01:38:22 -08001841 inst = kmalloc(sizeof(struct kretprobe_instance) +
1842 rp->data_size, GFP_KERNEL);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001843 if (inst == NULL) {
1844 free_rp_inst(rp);
1845 return -ENOMEM;
1846 }
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001847 INIT_HLIST_NODE(&inst->hlist);
1848 hlist_add_head(&inst->hlist, &rp->free_instances);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001849 }
1850
1851 rp->nmissed = 0;
1852 /* Establish function entry probe point */
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -08001853 ret = register_kprobe(&rp->kp);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001854 if (ret != 0)
Hien Nguyenb94cce92005-06-23 00:09:19 -07001855 free_rp_inst(rp);
1856 return ret;
1857}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001858EXPORT_SYMBOL_GPL(register_kretprobe);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001859
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -08001860int __kprobes register_kretprobes(struct kretprobe **rps, int num)
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001861{
1862 int ret = 0, i;
1863
1864 if (num <= 0)
1865 return -EINVAL;
1866 for (i = 0; i < num; i++) {
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -08001867 ret = register_kretprobe(rps[i]);
Masami Hiramatsu67dddaa2008-06-12 15:21:35 -07001868 if (ret < 0) {
1869 if (i > 0)
1870 unregister_kretprobes(rps, i);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001871 break;
1872 }
1873 }
1874 return ret;
1875}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001876EXPORT_SYMBOL_GPL(register_kretprobes);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001877
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001878void __kprobes unregister_kretprobe(struct kretprobe *rp)
1879{
1880 unregister_kretprobes(&rp, 1);
1881}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001882EXPORT_SYMBOL_GPL(unregister_kretprobe);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001883
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001884void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
1885{
1886 int i;
1887
1888 if (num <= 0)
1889 return;
1890 mutex_lock(&kprobe_mutex);
1891 for (i = 0; i < num; i++)
1892 if (__unregister_kprobe_top(&rps[i]->kp) < 0)
1893 rps[i]->kp.addr = NULL;
1894 mutex_unlock(&kprobe_mutex);
1895
1896 synchronize_sched();
1897 for (i = 0; i < num; i++) {
1898 if (rps[i]->kp.addr) {
1899 __unregister_kprobe_bottom(&rps[i]->kp);
1900 cleanup_rp_inst(rps[i]);
1901 }
1902 }
1903}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001904EXPORT_SYMBOL_GPL(unregister_kretprobes);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001905
Ananth N Mavinakayanahalli9edddaa2008-03-04 14:28:37 -08001906#else /* CONFIG_KRETPROBES */
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -07001907int __kprobes register_kretprobe(struct kretprobe *rp)
Hien Nguyenb94cce92005-06-23 00:09:19 -07001908{
1909 return -ENOSYS;
1910}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001911EXPORT_SYMBOL_GPL(register_kretprobe);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001912
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001913int __kprobes register_kretprobes(struct kretprobe **rps, int num)
1914{
1915 return -ENOSYS;
1916}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001917EXPORT_SYMBOL_GPL(register_kretprobes);
1918
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001919void __kprobes unregister_kretprobe(struct kretprobe *rp)
1920{
1921}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001922EXPORT_SYMBOL_GPL(unregister_kretprobe);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001923
1924void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
1925{
1926}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001927EXPORT_SYMBOL_GPL(unregister_kretprobes);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001928
Srinivasa Ds346fd592007-02-20 13:57:54 -08001929static int __kprobes pre_handler_kretprobe(struct kprobe *p,
1930 struct pt_regs *regs)
1931{
1932 return 0;
1933}
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001934
Ananth N Mavinakayanahalli9edddaa2008-03-04 14:28:37 -08001935#endif /* CONFIG_KRETPROBES */
Hien Nguyenb94cce92005-06-23 00:09:19 -07001936
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001937/* Set the kprobe gone and remove its instruction buffer. */
1938static void __kprobes kill_kprobe(struct kprobe *p)
1939{
1940 struct kprobe *kp;
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001941
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001942 p->flags |= KPROBE_FLAG_GONE;
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001943 if (kprobe_aggrprobe(p)) {
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001944 /*
1945 * If this is an aggr_kprobe, we have to list all the
1946 * chained probes and mark them GONE.
1947 */
1948 list_for_each_entry_rcu(kp, &p->list, list)
1949 kp->flags |= KPROBE_FLAG_GONE;
1950 p->post_handler = NULL;
1951 p->break_handler = NULL;
Masami Hiramatsuafd66252010-02-25 08:34:07 -05001952 kill_optimized_kprobe(p);
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001953 }
1954 /*
1955 * Here, we can remove insn_slot safely, because no thread calls
1956 * the original probed function (which will be freed soon) any more.
1957 */
1958 arch_remove_kprobe(p);
1959}
1960
Masami Hiramatsuc0614822010-04-27 18:33:12 -04001961/* Disable one kprobe */
1962int __kprobes disable_kprobe(struct kprobe *kp)
1963{
1964 int ret = 0;
Masami Hiramatsuc0614822010-04-27 18:33:12 -04001965
1966 mutex_lock(&kprobe_mutex);
1967
Masami Hiramatsu6f0f1dd2010-12-03 18:53:57 +09001968 /* Disable this kprobe */
1969 if (__disable_kprobe(kp) == NULL)
Masami Hiramatsuc0614822010-04-27 18:33:12 -04001970 ret = -EINVAL;
Masami Hiramatsuc0614822010-04-27 18:33:12 -04001971
Masami Hiramatsuc0614822010-04-27 18:33:12 -04001972 mutex_unlock(&kprobe_mutex);
1973 return ret;
1974}
1975EXPORT_SYMBOL_GPL(disable_kprobe);
1976
1977/* Enable one kprobe */
1978int __kprobes enable_kprobe(struct kprobe *kp)
1979{
1980 int ret = 0;
1981 struct kprobe *p;
1982
1983 mutex_lock(&kprobe_mutex);
1984
1985 /* Check whether specified probe is valid. */
1986 p = __get_valid_kprobe(kp);
1987 if (unlikely(p == NULL)) {
1988 ret = -EINVAL;
1989 goto out;
1990 }
1991
1992 if (kprobe_gone(kp)) {
1993 /* This kprobe has gone, we couldn't enable it. */
1994 ret = -EINVAL;
1995 goto out;
1996 }
1997
1998 if (p != kp)
1999 kp->flags &= ~KPROBE_FLAG_DISABLED;
2000
2001 if (!kprobes_all_disarmed && kprobe_disabled(p)) {
2002 p->flags &= ~KPROBE_FLAG_DISABLED;
2003 arm_kprobe(p);
2004 }
2005out:
2006 mutex_unlock(&kprobe_mutex);
2007 return ret;
2008}
2009EXPORT_SYMBOL_GPL(enable_kprobe);
2010
Frederic Weisbecker24851d22009-08-26 23:38:30 +02002011void __kprobes dump_kprobe(struct kprobe *kp)
2012{
2013 printk(KERN_WARNING "Dumping kprobe:\n");
2014 printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n",
2015 kp->symbol_name, kp->addr, kp->offset);
2016}
2017
Masami Hiramatsue8386a02009-01-06 14:41:52 -08002018/* Module notifier call back, checking kprobes on the module */
2019static int __kprobes kprobes_module_callback(struct notifier_block *nb,
2020 unsigned long val, void *data)
2021{
2022 struct module *mod = data;
2023 struct hlist_head *head;
2024 struct hlist_node *node;
2025 struct kprobe *p;
2026 unsigned int i;
Masami Hiramatsuf24659d2009-01-06 14:41:55 -08002027 int checkcore = (val == MODULE_STATE_GOING);
Masami Hiramatsue8386a02009-01-06 14:41:52 -08002028
Masami Hiramatsuf24659d2009-01-06 14:41:55 -08002029 if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
Masami Hiramatsue8386a02009-01-06 14:41:52 -08002030 return NOTIFY_DONE;
2031
2032 /*
Masami Hiramatsuf24659d2009-01-06 14:41:55 -08002033 * When MODULE_STATE_GOING was notified, both of module .text and
2034 * .init.text sections would be freed. When MODULE_STATE_LIVE was
2035 * notified, only .init.text section would be freed. We need to
2036 * disable kprobes which have been inserted in the sections.
Masami Hiramatsue8386a02009-01-06 14:41:52 -08002037 */
2038 mutex_lock(&kprobe_mutex);
2039 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2040 head = &kprobe_table[i];
2041 hlist_for_each_entry_rcu(p, node, head, hlist)
Masami Hiramatsuf24659d2009-01-06 14:41:55 -08002042 if (within_module_init((unsigned long)p->addr, mod) ||
2043 (checkcore &&
2044 within_module_core((unsigned long)p->addr, mod))) {
Masami Hiramatsue8386a02009-01-06 14:41:52 -08002045 /*
2046 * The vaddr this probe is installed will soon
2047 * be vfreed buy not synced to disk. Hence,
2048 * disarming the breakpoint isn't needed.
2049 */
2050 kill_kprobe(p);
2051 }
2052 }
2053 mutex_unlock(&kprobe_mutex);
2054 return NOTIFY_DONE;
2055}
2056
2057static struct notifier_block kprobe_module_nb = {
2058 .notifier_call = kprobes_module_callback,
2059 .priority = 0
2060};
2061
Linus Torvalds1da177e2005-04-16 15:20:36 -07002062static int __init init_kprobes(void)
2063{
2064 int i, err = 0;
Srinivasa Ds3d8d9962008-04-28 02:14:26 -07002065 unsigned long offset = 0, size = 0;
2066 char *modname, namebuf[128];
2067 const char *symbol_name;
2068 void *addr;
2069 struct kprobe_blackpoint *kb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002070
2071 /* FIXME allocate the probe table, currently defined statically */
2072 /* initialize all list heads */
Hien Nguyenb94cce92005-06-23 00:09:19 -07002073 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002074 INIT_HLIST_HEAD(&kprobe_table[i]);
Hien Nguyenb94cce92005-06-23 00:09:19 -07002075 INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
Thomas Gleixnerec4846082009-07-25 16:09:17 +02002076 raw_spin_lock_init(&(kretprobe_table_locks[i].lock));
Hien Nguyenb94cce92005-06-23 00:09:19 -07002077 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002078
Srinivasa Ds3d8d9962008-04-28 02:14:26 -07002079 /*
2080 * Lookup and populate the kprobe_blacklist.
2081 *
2082 * Unlike the kretprobe blacklist, we'll need to determine
2083 * the range of addresses that belong to the said functions,
2084 * since a kprobe need not necessarily be at the beginning
2085 * of a function.
2086 */
2087 for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
2088 kprobe_lookup_name(kb->name, addr);
2089 if (!addr)
2090 continue;
2091
2092 kb->start_addr = (unsigned long)addr;
2093 symbol_name = kallsyms_lookup(kb->start_addr,
2094 &size, &offset, &modname, namebuf);
2095 if (!symbol_name)
2096 kb->range = 0;
2097 else
2098 kb->range = size;
2099 }
2100
Masami Hiramatsuf438d912007-10-16 01:27:49 -07002101 if (kretprobe_blacklist_size) {
2102 /* lookup the function address from its name */
2103 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
2104 kprobe_lookup_name(kretprobe_blacklist[i].name,
2105 kretprobe_blacklist[i].addr);
2106 if (!kretprobe_blacklist[i].addr)
2107 printk("kretprobe: lookup failed: %s\n",
2108 kretprobe_blacklist[i].name);
2109 }
2110 }
2111
Masami Hiramatsub2be84d2010-02-25 08:34:15 -05002112#if defined(CONFIG_OPTPROBES)
2113#if defined(__ARCH_WANT_KPROBES_INSN_SLOT)
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002114 /* Init kprobe_optinsn_slots */
2115 kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
2116#endif
Masami Hiramatsub2be84d2010-02-25 08:34:15 -05002117 /* By default, kprobes can be optimized */
2118 kprobes_allow_optimization = true;
2119#endif
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002120
Masami Hiramatsue579abe2009-04-06 19:01:01 -07002121 /* By default, kprobes are armed */
2122 kprobes_all_disarmed = false;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002123
Rusty Lynch67729262005-07-05 18:54:50 -07002124 err = arch_init_kprobes();
Rusty Lynch802eae72005-06-27 15:17:08 -07002125 if (!err)
2126 err = register_die_notifier(&kprobe_exceptions_nb);
Masami Hiramatsue8386a02009-01-06 14:41:52 -08002127 if (!err)
2128 err = register_module_notifier(&kprobe_module_nb);
2129
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07002130 kprobes_initialized = (err == 0);
Rusty Lynch802eae72005-06-27 15:17:08 -07002131
Ananth N Mavinakayanahalli8c1c9352008-01-30 13:32:53 +01002132 if (!err)
2133 init_test_probes();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002134 return err;
2135}
2136
Srinivasa Ds346fd592007-02-20 13:57:54 -08002137#ifdef CONFIG_DEBUG_FS
2138static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p,
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002139 const char *sym, int offset, char *modname, struct kprobe *pp)
Srinivasa Ds346fd592007-02-20 13:57:54 -08002140{
2141 char *kprobe_type;
2142
2143 if (p->pre_handler == pre_handler_kretprobe)
2144 kprobe_type = "r";
2145 else if (p->pre_handler == setjmp_pre_handler)
2146 kprobe_type = "j";
2147 else
2148 kprobe_type = "k";
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002149
Srinivasa Ds346fd592007-02-20 13:57:54 -08002150 if (sym)
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002151 seq_printf(pi, "%p %s %s+0x%x %s ",
Masami Hiramatsude5bd882009-04-06 19:01:02 -07002152 p->addr, kprobe_type, sym, offset,
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002153 (modname ? modname : " "));
Srinivasa Ds346fd592007-02-20 13:57:54 -08002154 else
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002155 seq_printf(pi, "%p %s %p ",
2156 p->addr, kprobe_type, p->addr);
2157
2158 if (!pp)
2159 pp = p;
Masami Hiramatsuae6aa162012-06-05 19:28:32 +09002160 seq_printf(pi, "%s%s%s%s\n",
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002161 (kprobe_gone(p) ? "[GONE]" : ""),
2162 ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""),
Masami Hiramatsuae6aa162012-06-05 19:28:32 +09002163 (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""),
2164 (kprobe_ftrace(pp) ? "[FTRACE]" : ""));
Srinivasa Ds346fd592007-02-20 13:57:54 -08002165}
2166
2167static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos)
2168{
2169 return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
2170}
2171
2172static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
2173{
2174 (*pos)++;
2175 if (*pos >= KPROBE_TABLE_SIZE)
2176 return NULL;
2177 return pos;
2178}
2179
2180static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v)
2181{
2182 /* Nothing to do */
2183}
2184
2185static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v)
2186{
2187 struct hlist_head *head;
2188 struct hlist_node *node;
2189 struct kprobe *p, *kp;
2190 const char *sym = NULL;
2191 unsigned int i = *(loff_t *) v;
Alexey Dobriyanffb45122007-05-08 00:28:41 -07002192 unsigned long offset = 0;
Srinivasa Ds346fd592007-02-20 13:57:54 -08002193 char *modname, namebuf[128];
2194
2195 head = &kprobe_table[i];
2196 preempt_disable();
2197 hlist_for_each_entry_rcu(p, node, head, hlist) {
Alexey Dobriyanffb45122007-05-08 00:28:41 -07002198 sym = kallsyms_lookup((unsigned long)p->addr, NULL,
Srinivasa Ds346fd592007-02-20 13:57:54 -08002199 &offset, &modname, namebuf);
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002200 if (kprobe_aggrprobe(p)) {
Srinivasa Ds346fd592007-02-20 13:57:54 -08002201 list_for_each_entry_rcu(kp, &p->list, list)
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002202 report_probe(pi, kp, sym, offset, modname, p);
Srinivasa Ds346fd592007-02-20 13:57:54 -08002203 } else
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002204 report_probe(pi, p, sym, offset, modname, NULL);
Srinivasa Ds346fd592007-02-20 13:57:54 -08002205 }
2206 preempt_enable();
2207 return 0;
2208}
2209
James Morris88e9d342009-09-22 16:43:43 -07002210static const struct seq_operations kprobes_seq_ops = {
Srinivasa Ds346fd592007-02-20 13:57:54 -08002211 .start = kprobe_seq_start,
2212 .next = kprobe_seq_next,
2213 .stop = kprobe_seq_stop,
2214 .show = show_kprobe_addr
2215};
2216
2217static int __kprobes kprobes_open(struct inode *inode, struct file *filp)
2218{
2219 return seq_open(filp, &kprobes_seq_ops);
2220}
2221
Alexey Dobriyan828c0952009-10-01 15:43:56 -07002222static const struct file_operations debugfs_kprobes_operations = {
Srinivasa Ds346fd592007-02-20 13:57:54 -08002223 .open = kprobes_open,
2224 .read = seq_read,
2225 .llseek = seq_lseek,
2226 .release = seq_release,
2227};
2228
Masami Hiramatsue579abe2009-04-06 19:01:01 -07002229static void __kprobes arm_all_kprobes(void)
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002230{
2231 struct hlist_head *head;
2232 struct hlist_node *node;
2233 struct kprobe *p;
2234 unsigned int i;
2235
2236 mutex_lock(&kprobe_mutex);
2237
Masami Hiramatsue579abe2009-04-06 19:01:01 -07002238 /* If kprobes are armed, just return */
2239 if (!kprobes_all_disarmed)
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002240 goto already_enabled;
2241
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002242 /* Arming kprobes doesn't optimize kprobe itself */
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002243 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2244 head = &kprobe_table[i];
2245 hlist_for_each_entry_rcu(p, node, head, hlist)
Masami Hiramatsude5bd882009-04-06 19:01:02 -07002246 if (!kprobe_disabled(p))
Masami Hiramatsuae6aa162012-06-05 19:28:32 +09002247 arm_kprobe(p);
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002248 }
2249
Masami Hiramatsue579abe2009-04-06 19:01:01 -07002250 kprobes_all_disarmed = false;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002251 printk(KERN_INFO "Kprobes globally enabled\n");
2252
2253already_enabled:
2254 mutex_unlock(&kprobe_mutex);
2255 return;
2256}
2257
Masami Hiramatsue579abe2009-04-06 19:01:01 -07002258static void __kprobes disarm_all_kprobes(void)
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002259{
2260 struct hlist_head *head;
2261 struct hlist_node *node;
2262 struct kprobe *p;
2263 unsigned int i;
2264
2265 mutex_lock(&kprobe_mutex);
2266
Masami Hiramatsue579abe2009-04-06 19:01:01 -07002267 /* If kprobes are already disarmed, just return */
Masami Hiramatsu6274de42010-12-03 18:54:09 +09002268 if (kprobes_all_disarmed) {
2269 mutex_unlock(&kprobe_mutex);
2270 return;
2271 }
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002272
Masami Hiramatsue579abe2009-04-06 19:01:01 -07002273 kprobes_all_disarmed = true;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002274 printk(KERN_INFO "Kprobes globally disabled\n");
Masami Hiramatsuafd66252010-02-25 08:34:07 -05002275
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002276 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2277 head = &kprobe_table[i];
2278 hlist_for_each_entry_rcu(p, node, head, hlist) {
Masami Hiramatsude5bd882009-04-06 19:01:02 -07002279 if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p))
Masami Hiramatsuae6aa162012-06-05 19:28:32 +09002280 disarm_kprobe(p, false);
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002281 }
2282 }
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002283 mutex_unlock(&kprobe_mutex);
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002284
Masami Hiramatsu6274de42010-12-03 18:54:09 +09002285 /* Wait for disarming all kprobes by optimizer */
2286 wait_for_kprobe_optimizer();
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002287}
2288
2289/*
2290 * XXX: The debugfs bool file interface doesn't allow for callbacks
2291 * when the bool state is switched. We can reuse that facility when
2292 * available
2293 */
2294static ssize_t read_enabled_file_bool(struct file *file,
2295 char __user *user_buf, size_t count, loff_t *ppos)
2296{
2297 char buf[3];
2298
Masami Hiramatsue579abe2009-04-06 19:01:01 -07002299 if (!kprobes_all_disarmed)
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002300 buf[0] = '1';
2301 else
2302 buf[0] = '0';
2303 buf[1] = '\n';
2304 buf[2] = 0x00;
2305 return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
2306}
2307
2308static ssize_t write_enabled_file_bool(struct file *file,
2309 const char __user *user_buf, size_t count, loff_t *ppos)
2310{
2311 char buf[32];
Stephen Boydefeb1562012-01-12 17:17:11 -08002312 size_t buf_size;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002313
2314 buf_size = min(count, (sizeof(buf)-1));
2315 if (copy_from_user(buf, user_buf, buf_size))
2316 return -EFAULT;
2317
2318 switch (buf[0]) {
2319 case 'y':
2320 case 'Y':
2321 case '1':
Masami Hiramatsue579abe2009-04-06 19:01:01 -07002322 arm_all_kprobes();
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002323 break;
2324 case 'n':
2325 case 'N':
2326 case '0':
Masami Hiramatsue579abe2009-04-06 19:01:01 -07002327 disarm_all_kprobes();
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002328 break;
2329 }
2330
2331 return count;
2332}
2333
Alexey Dobriyan828c0952009-10-01 15:43:56 -07002334static const struct file_operations fops_kp = {
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002335 .read = read_enabled_file_bool,
2336 .write = write_enabled_file_bool,
Arnd Bergmann6038f372010-08-15 18:52:59 +02002337 .llseek = default_llseek,
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002338};
2339
Srinivasa Ds346fd592007-02-20 13:57:54 -08002340static int __kprobes debugfs_kprobe_init(void)
2341{
2342 struct dentry *dir, *file;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002343 unsigned int value = 1;
Srinivasa Ds346fd592007-02-20 13:57:54 -08002344
2345 dir = debugfs_create_dir("kprobes", NULL);
2346 if (!dir)
2347 return -ENOMEM;
2348
Randy Dunlape3869792007-05-08 00:27:01 -07002349 file = debugfs_create_file("list", 0444, dir, NULL,
Srinivasa Ds346fd592007-02-20 13:57:54 -08002350 &debugfs_kprobes_operations);
2351 if (!file) {
2352 debugfs_remove(dir);
2353 return -ENOMEM;
2354 }
2355
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07002356 file = debugfs_create_file("enabled", 0600, dir,
2357 &value, &fops_kp);
2358 if (!file) {
2359 debugfs_remove(dir);
2360 return -ENOMEM;
2361 }
2362
Srinivasa Ds346fd592007-02-20 13:57:54 -08002363 return 0;
2364}
2365
2366late_initcall(debugfs_kprobe_init);
2367#endif /* CONFIG_DEBUG_FS */
2368
2369module_init(init_kprobes);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002370
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07002371/* defined in arch/.../kernel/kprobes.c */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002372EXPORT_SYMBOL_GPL(jprobe_return);