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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Kernel Probes (KProbes)
3 * kernel/kprobes.c
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 *
19 * Copyright (C) IBM Corporation, 2002, 2004
20 *
21 * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
22 * Probes initial implementation (includes suggestions from
23 * Rusty Russell).
24 * 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with
25 * hlists and exceptions notifier as suggested by Andi Kleen.
26 * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
27 * interface to access function arguments.
28 * 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes
29 * exceptions notifier to be first on the priority list.
Hien Nguyenb94cce92005-06-23 00:09:19 -070030 * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston
31 * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
32 * <prasanna@in.ibm.com> added function-return probes.
Linus Torvalds1da177e2005-04-16 15:20:36 -070033 */
34#include <linux/kprobes.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070035#include <linux/hash.h>
36#include <linux/init.h>
Tim Schmielau4e57b682005-10-30 15:03:48 -080037#include <linux/slab.h>
Randy Dunlape3869792007-05-08 00:27:01 -070038#include <linux/stddef.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070039#include <linux/module.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>
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -070045#include <linux/kdebug.h>
Mathieu Desnoyers4460fda2009-03-06 10:36:38 -050046#include <linux/memory.h>
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -070047
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -070048#include <asm-generic/sections.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070049#include <asm/cacheflush.h>
50#include <asm/errno.h>
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -070051#include <asm/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070052
53#define KPROBE_HASH_BITS 6
54#define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
55
Ananth N Mavinakayanahalli3a872d82006-10-02 02:17:30 -070056
57/*
58 * Some oddball architectures like 64bit powerpc have function descriptors
59 * so this must be overridable.
60 */
61#ifndef kprobe_lookup_name
62#define kprobe_lookup_name(name, addr) \
63 addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name)))
64#endif
65
Srinivasa D Sef53d9c2008-07-25 01:46:04 -070066static int kprobes_initialized;
Linus Torvalds1da177e2005-04-16 15:20:36 -070067static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
Hien Nguyenb94cce92005-06-23 00:09:19 -070068static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
Linus Torvalds1da177e2005-04-16 15:20:36 -070069
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -070070/* NOTE: change this value only with kprobe_mutex held */
Masami Hiramatsue579abe2009-04-06 19:01:01 -070071static bool kprobes_all_disarmed;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -070072
Masami Hiramatsu12941562009-01-06 14:41:50 -080073static DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -080074static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
Srinivasa D Sef53d9c2008-07-25 01:46:04 -070075static struct {
Andrew Morton7e036d02008-11-12 13:26:57 -080076 spinlock_t lock ____cacheline_aligned_in_smp;
Srinivasa D Sef53d9c2008-07-25 01:46:04 -070077} kretprobe_table_locks[KPROBE_TABLE_SIZE];
78
79static spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
80{
81 return &(kretprobe_table_locks[hash].lock);
82}
Linus Torvalds1da177e2005-04-16 15:20:36 -070083
Srinivasa Ds3d8d9962008-04-28 02:14:26 -070084/*
85 * Normally, functions that we'd want to prohibit kprobes in, are marked
86 * __kprobes. But, there are cases where such functions already belong to
87 * a different section (__sched for preempt_schedule)
88 *
89 * For such cases, we now have a blacklist
90 */
Daniel Guilak544304b2008-07-10 09:38:19 -070091static struct kprobe_blackpoint kprobe_blacklist[] = {
Srinivasa Ds3d8d9962008-04-28 02:14:26 -070092 {"preempt_schedule",},
93 {NULL} /* Terminator */
94};
95
Anil S Keshavamurthy2d14e392006-01-09 20:52:41 -080096#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -070097/*
98 * kprobe->ainsn.insn points to the copy of the instruction to be
99 * single-stepped. x86_64, POWER4 and above have no-exec support and
100 * stepping on the instruction on a vmalloced/kmalloced/data page
101 * is a recipe for disaster
102 */
103#define INSNS_PER_PAGE (PAGE_SIZE/(MAX_INSN_SIZE * sizeof(kprobe_opcode_t)))
104
105struct kprobe_insn_page {
Masami Hiramatsuc5cb5a22009-06-30 17:08:14 -0400106 struct list_head list;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700107 kprobe_opcode_t *insns; /* Page of instruction slots */
108 char slot_used[INSNS_PER_PAGE];
109 int nused;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800110 int ngarbage;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700111};
112
Masami Hiramatsuab40c5c2007-01-30 14:36:06 -0800113enum kprobe_slot_state {
114 SLOT_CLEAN = 0,
115 SLOT_DIRTY = 1,
116 SLOT_USED = 2,
117};
118
Masami Hiramatsu12941562009-01-06 14:41:50 -0800119static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_pages */
Masami Hiramatsuc5cb5a22009-06-30 17:08:14 -0400120static LIST_HEAD(kprobe_insn_pages);
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800121static int kprobe_garbage_slots;
122static int collect_garbage_slots(void);
123
124static int __kprobes check_safety(void)
125{
126 int ret = 0;
Masami Hiramatsu5a4ccaf2009-01-06 21:15:32 +0100127#if defined(CONFIG_PREEMPT) && defined(CONFIG_FREEZER)
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800128 ret = freeze_processes();
129 if (ret == 0) {
130 struct task_struct *p, *q;
131 do_each_thread(p, q) {
132 if (p != current && p->state == TASK_RUNNING &&
133 p->pid != 0) {
134 printk("Check failed: %s is running\n",p->comm);
135 ret = -1;
136 goto loop_end;
137 }
138 } while_each_thread(p, q);
139 }
140loop_end:
141 thaw_processes();
142#else
143 synchronize_sched();
144#endif
145 return ret;
146}
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700147
148/**
Masami Hiramatsu12941562009-01-06 14:41:50 -0800149 * __get_insn_slot() - Find a slot on an executable page for an instruction.
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700150 * We allocate an executable page if there's no room on existing ones.
151 */
Masami Hiramatsu12941562009-01-06 14:41:50 -0800152static kprobe_opcode_t __kprobes *__get_insn_slot(void)
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700153{
154 struct kprobe_insn_page *kip;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700155
Christoph Hellwig6f716ac2007-05-08 00:34:13 -0700156 retry:
Masami Hiramatsuc5cb5a22009-06-30 17:08:14 -0400157 list_for_each_entry(kip, &kprobe_insn_pages, list) {
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700158 if (kip->nused < INSNS_PER_PAGE) {
159 int i;
160 for (i = 0; i < INSNS_PER_PAGE; i++) {
Masami Hiramatsuab40c5c2007-01-30 14:36:06 -0800161 if (kip->slot_used[i] == SLOT_CLEAN) {
162 kip->slot_used[i] = SLOT_USED;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700163 kip->nused++;
164 return kip->insns + (i * MAX_INSN_SIZE);
165 }
166 }
167 /* Surprise! No unused slots. Fix kip->nused. */
168 kip->nused = INSNS_PER_PAGE;
169 }
170 }
171
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800172 /* If there are any garbage slots, collect it and try again. */
173 if (kprobe_garbage_slots && collect_garbage_slots() == 0) {
174 goto retry;
175 }
176 /* All out of space. Need to allocate a new page. Use slot 0. */
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700177 kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL);
Christoph Hellwig6f716ac2007-05-08 00:34:13 -0700178 if (!kip)
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700179 return NULL;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700180
181 /*
182 * Use module_alloc so this page is within +/- 2GB of where the
183 * kernel image and loaded module images reside. This is required
184 * so x86_64 can correctly handle the %rip-relative fixups.
185 */
186 kip->insns = module_alloc(PAGE_SIZE);
187 if (!kip->insns) {
188 kfree(kip);
189 return NULL;
190 }
Masami Hiramatsuc5cb5a22009-06-30 17:08:14 -0400191 INIT_LIST_HEAD(&kip->list);
192 list_add(&kip->list, &kprobe_insn_pages);
Masami Hiramatsuab40c5c2007-01-30 14:36:06 -0800193 memset(kip->slot_used, SLOT_CLEAN, INSNS_PER_PAGE);
194 kip->slot_used[0] = SLOT_USED;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700195 kip->nused = 1;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800196 kip->ngarbage = 0;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700197 return kip->insns;
198}
199
Masami Hiramatsu12941562009-01-06 14:41:50 -0800200kprobe_opcode_t __kprobes *get_insn_slot(void)
201{
202 kprobe_opcode_t *ret;
203 mutex_lock(&kprobe_insn_mutex);
204 ret = __get_insn_slot();
205 mutex_unlock(&kprobe_insn_mutex);
206 return ret;
207}
208
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800209/* Return 1 if all garbages are collected, otherwise 0. */
210static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
211{
Masami Hiramatsuab40c5c2007-01-30 14:36:06 -0800212 kip->slot_used[idx] = SLOT_CLEAN;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800213 kip->nused--;
214 if (kip->nused == 0) {
215 /*
216 * Page is no longer in use. Free it unless
217 * it's the last one. We keep the last one
218 * so as not to have to set it up again the
219 * next time somebody inserts a probe.
220 */
Masami Hiramatsuc5cb5a22009-06-30 17:08:14 -0400221 if (!list_is_singular(&kprobe_insn_pages)) {
222 list_del(&kip->list);
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800223 module_free(NULL, kip->insns);
224 kfree(kip);
225 }
226 return 1;
227 }
228 return 0;
229}
230
231static int __kprobes collect_garbage_slots(void)
232{
Masami Hiramatsuc5cb5a22009-06-30 17:08:14 -0400233 struct kprobe_insn_page *kip, *next;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800234
235 /* Ensure no-one is preepmted on the garbages */
Masami Hiramatsu4a2bb6f2009-06-30 17:08:09 -0400236 if (check_safety())
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800237 return -EAGAIN;
238
Masami Hiramatsuc5cb5a22009-06-30 17:08:14 -0400239 list_for_each_entry_safe(kip, next, &kprobe_insn_pages, list) {
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800240 int i;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800241 if (kip->ngarbage == 0)
242 continue;
243 kip->ngarbage = 0; /* we will collect all garbages */
244 for (i = 0; i < INSNS_PER_PAGE; i++) {
Masami Hiramatsuab40c5c2007-01-30 14:36:06 -0800245 if (kip->slot_used[i] == SLOT_DIRTY &&
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800246 collect_one_slot(kip, i))
247 break;
248 }
249 }
250 kprobe_garbage_slots = 0;
251 return 0;
252}
253
254void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700255{
256 struct kprobe_insn_page *kip;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700257
Masami Hiramatsu12941562009-01-06 14:41:50 -0800258 mutex_lock(&kprobe_insn_mutex);
Masami Hiramatsuc5cb5a22009-06-30 17:08:14 -0400259 list_for_each_entry(kip, &kprobe_insn_pages, list) {
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700260 if (kip->insns <= slot &&
261 slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) {
262 int i = (slot - kip->insns) / MAX_INSN_SIZE;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800263 if (dirty) {
Masami Hiramatsuab40c5c2007-01-30 14:36:06 -0800264 kip->slot_used[i] = SLOT_DIRTY;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800265 kip->ngarbage++;
Masami Hiramatsuc5cb5a22009-06-30 17:08:14 -0400266 } else
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800267 collect_one_slot(kip, i);
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800268 break;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700269 }
270 }
Christoph Hellwig6f716ac2007-05-08 00:34:13 -0700271
272 if (dirty && ++kprobe_garbage_slots > INSNS_PER_PAGE)
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800273 collect_garbage_slots();
Masami Hiramatsu12941562009-01-06 14:41:50 -0800274
275 mutex_unlock(&kprobe_insn_mutex);
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700276}
Anil S Keshavamurthy2d14e392006-01-09 20:52:41 -0800277#endif
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700278
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800279/* We have preemption disabled.. so it is safe to use __ versions */
280static inline void set_kprobe_instance(struct kprobe *kp)
281{
282 __get_cpu_var(kprobe_instance) = kp;
283}
284
285static inline void reset_kprobe_instance(void)
286{
287 __get_cpu_var(kprobe_instance) = NULL;
288}
289
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800290/*
291 * This routine is called either:
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -0800292 * - under the kprobe_mutex - during kprobe_[un]register()
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800293 * OR
Ananth N Mavinakayanahallid217d542005-11-07 01:00:14 -0800294 * - with preemption disabled - from arch/xxx/kernel/kprobes.c
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800295 */
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700296struct kprobe __kprobes *get_kprobe(void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297{
298 struct hlist_head *head;
299 struct hlist_node *node;
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800300 struct kprobe *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301
302 head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800303 hlist_for_each_entry_rcu(p, node, head, hlist) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 if (p->addr == addr)
305 return p;
306 }
307 return NULL;
308}
309
Masami Hiramatsu201517a2009-05-07 16:31:26 -0400310/* Arm a kprobe with text_mutex */
311static void __kprobes arm_kprobe(struct kprobe *kp)
312{
313 mutex_lock(&text_mutex);
314 arch_arm_kprobe(kp);
315 mutex_unlock(&text_mutex);
316}
317
318/* Disarm a kprobe with text_mutex */
319static void __kprobes disarm_kprobe(struct kprobe *kp)
320{
321 mutex_lock(&text_mutex);
322 arch_disarm_kprobe(kp);
323 mutex_unlock(&text_mutex);
324}
325
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700326/*
327 * Aggregate handlers for multiple kprobes support - these handlers
328 * take care of invoking the individual kprobe handlers on p->list
329 */
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700330static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700331{
332 struct kprobe *kp;
333
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800334 list_for_each_entry_rcu(kp, &p->list, list) {
Masami Hiramatsude5bd882009-04-06 19:01:02 -0700335 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800336 set_kprobe_instance(kp);
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700337 if (kp->pre_handler(kp, regs))
338 return 1;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700339 }
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800340 reset_kprobe_instance();
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700341 }
342 return 0;
343}
344
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700345static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
346 unsigned long flags)
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700347{
348 struct kprobe *kp;
349
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800350 list_for_each_entry_rcu(kp, &p->list, list) {
Masami Hiramatsude5bd882009-04-06 19:01:02 -0700351 if (kp->post_handler && likely(!kprobe_disabled(kp))) {
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800352 set_kprobe_instance(kp);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700353 kp->post_handler(kp, regs, flags);
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800354 reset_kprobe_instance();
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700355 }
356 }
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700357}
358
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700359static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
360 int trapnr)
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700361{
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800362 struct kprobe *cur = __get_cpu_var(kprobe_instance);
363
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700364 /*
365 * if we faulted "during" the execution of a user specified
366 * probe handler, invoke just that probe's fault handler
367 */
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800368 if (cur && cur->fault_handler) {
369 if (cur->fault_handler(cur, regs, trapnr))
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700370 return 1;
371 }
372 return 0;
373}
374
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700375static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700376{
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800377 struct kprobe *cur = __get_cpu_var(kprobe_instance);
378 int ret = 0;
379
380 if (cur && cur->break_handler) {
381 if (cur->break_handler(cur, regs))
382 ret = 1;
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700383 }
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800384 reset_kprobe_instance();
385 return ret;
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700386}
387
Keshavamurthy Anil Sbf8d5c52005-12-12 00:37:34 -0800388/* Walks the list and increments nmissed count for multiprobe case */
389void __kprobes kprobes_inc_nmissed_count(struct kprobe *p)
390{
391 struct kprobe *kp;
392 if (p->pre_handler != aggr_pre_handler) {
393 p->nmissed++;
394 } else {
395 list_for_each_entry_rcu(kp, &p->list, list)
396 kp->nmissed++;
397 }
398 return;
399}
400
bibo,mao99219a32006-10-02 02:17:35 -0700401void __kprobes recycle_rp_inst(struct kretprobe_instance *ri,
402 struct hlist_head *head)
Hien Nguyenb94cce92005-06-23 00:09:19 -0700403{
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700404 struct kretprobe *rp = ri->rp;
405
Hien Nguyenb94cce92005-06-23 00:09:19 -0700406 /* remove rp inst off the rprobe_inst_table */
407 hlist_del(&ri->hlist);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700408 INIT_HLIST_NODE(&ri->hlist);
409 if (likely(rp)) {
410 spin_lock(&rp->lock);
411 hlist_add_head(&ri->hlist, &rp->free_instances);
412 spin_unlock(&rp->lock);
Hien Nguyenb94cce92005-06-23 00:09:19 -0700413 } else
414 /* Unregistering */
bibo,mao99219a32006-10-02 02:17:35 -0700415 hlist_add_head(&ri->hlist, head);
Hien Nguyenb94cce92005-06-23 00:09:19 -0700416}
417
Masami Hiramatsu017c39b2009-01-06 14:41:51 -0800418void __kprobes kretprobe_hash_lock(struct task_struct *tsk,
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700419 struct hlist_head **head, unsigned long *flags)
Hien Nguyenb94cce92005-06-23 00:09:19 -0700420{
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700421 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
422 spinlock_t *hlist_lock;
423
424 *head = &kretprobe_inst_table[hash];
425 hlist_lock = kretprobe_table_lock_ptr(hash);
426 spin_lock_irqsave(hlist_lock, *flags);
427}
428
Masami Hiramatsu017c39b2009-01-06 14:41:51 -0800429static void __kprobes kretprobe_table_lock(unsigned long hash,
430 unsigned long *flags)
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700431{
432 spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
433 spin_lock_irqsave(hlist_lock, *flags);
434}
435
Masami Hiramatsu017c39b2009-01-06 14:41:51 -0800436void __kprobes kretprobe_hash_unlock(struct task_struct *tsk,
437 unsigned long *flags)
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700438{
439 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
440 spinlock_t *hlist_lock;
441
442 hlist_lock = kretprobe_table_lock_ptr(hash);
443 spin_unlock_irqrestore(hlist_lock, *flags);
444}
445
Masami Hiramatsu017c39b2009-01-06 14:41:51 -0800446void __kprobes kretprobe_table_unlock(unsigned long hash, unsigned long *flags)
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700447{
448 spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
449 spin_unlock_irqrestore(hlist_lock, *flags);
Hien Nguyenb94cce92005-06-23 00:09:19 -0700450}
451
Hien Nguyenb94cce92005-06-23 00:09:19 -0700452/*
bibo maoc6fd91f2006-03-26 01:38:20 -0800453 * This function is called from finish_task_switch when task tk becomes dead,
454 * so that we can recycle any function-return probe instances associated
455 * with this task. These left over instances represent probed functions
456 * that have been called but will never return.
Hien Nguyenb94cce92005-06-23 00:09:19 -0700457 */
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700458void __kprobes kprobe_flush_task(struct task_struct *tk)
Hien Nguyenb94cce92005-06-23 00:09:19 -0700459{
bibo,mao62c27be2006-10-02 02:17:33 -0700460 struct kretprobe_instance *ri;
bibo,mao99219a32006-10-02 02:17:35 -0700461 struct hlist_head *head, empty_rp;
Rusty Lynch802eae72005-06-27 15:17:08 -0700462 struct hlist_node *node, *tmp;
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700463 unsigned long hash, flags = 0;
Rusty Lynch802eae72005-06-27 15:17:08 -0700464
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700465 if (unlikely(!kprobes_initialized))
466 /* Early boot. kretprobe_table_locks not yet initialized. */
467 return;
468
469 hash = hash_ptr(tk, KPROBE_HASH_BITS);
470 head = &kretprobe_inst_table[hash];
471 kretprobe_table_lock(hash, &flags);
bibo,mao62c27be2006-10-02 02:17:33 -0700472 hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
473 if (ri->task == tk)
bibo,mao99219a32006-10-02 02:17:35 -0700474 recycle_rp_inst(ri, &empty_rp);
bibo,mao62c27be2006-10-02 02:17:33 -0700475 }
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700476 kretprobe_table_unlock(hash, &flags);
477 INIT_HLIST_HEAD(&empty_rp);
bibo,mao99219a32006-10-02 02:17:35 -0700478 hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
479 hlist_del(&ri->hlist);
480 kfree(ri);
481 }
Hien Nguyenb94cce92005-06-23 00:09:19 -0700482}
483
Hien Nguyenb94cce92005-06-23 00:09:19 -0700484static inline void free_rp_inst(struct kretprobe *rp)
485{
486 struct kretprobe_instance *ri;
Christoph Hellwig4c4308c2007-05-08 00:34:14 -0700487 struct hlist_node *pos, *next;
488
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700489 hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) {
490 hlist_del(&ri->hlist);
Hien Nguyenb94cce92005-06-23 00:09:19 -0700491 kfree(ri);
492 }
493}
494
Masami Hiramatsu4a296e02008-04-28 02:14:29 -0700495static void __kprobes cleanup_rp_inst(struct kretprobe *rp)
496{
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700497 unsigned long flags, hash;
Masami Hiramatsu4a296e02008-04-28 02:14:29 -0700498 struct kretprobe_instance *ri;
499 struct hlist_node *pos, *next;
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700500 struct hlist_head *head;
501
Masami Hiramatsu4a296e02008-04-28 02:14:29 -0700502 /* No race here */
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700503 for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) {
504 kretprobe_table_lock(hash, &flags);
505 head = &kretprobe_inst_table[hash];
506 hlist_for_each_entry_safe(ri, pos, next, head, hlist) {
507 if (ri->rp == rp)
508 ri->rp = NULL;
509 }
510 kretprobe_table_unlock(hash, &flags);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -0700511 }
Masami Hiramatsu4a296e02008-04-28 02:14:29 -0700512 free_rp_inst(rp);
513}
514
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700515/*
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700516 * Keep all fields in the kprobe consistent
517 */
518static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p)
519{
520 memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t));
521 memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn));
522}
523
524/*
Masami Hiramatsub918e5e2009-04-06 19:00:58 -0700525* Add the new probe to ap->list. Fail if this is the
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700526* second jprobe at the address - two jprobes can't coexist
527*/
Masami Hiramatsub918e5e2009-04-06 19:00:58 -0700528static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p)
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700529{
Masami Hiramatsude5bd882009-04-06 19:01:02 -0700530 BUG_ON(kprobe_gone(ap) || kprobe_gone(p));
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700531 if (p->break_handler) {
Masami Hiramatsub918e5e2009-04-06 19:00:58 -0700532 if (ap->break_handler)
mao, bibo36721652006-06-26 00:25:22 -0700533 return -EEXIST;
Masami Hiramatsub918e5e2009-04-06 19:00:58 -0700534 list_add_tail_rcu(&p->list, &ap->list);
535 ap->break_handler = aggr_break_handler;
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700536 } else
Masami Hiramatsub918e5e2009-04-06 19:00:58 -0700537 list_add_rcu(&p->list, &ap->list);
538 if (p->post_handler && !ap->post_handler)
539 ap->post_handler = aggr_post_handler;
Masami Hiramatsude5bd882009-04-06 19:01:02 -0700540
541 if (kprobe_disabled(ap) && !kprobe_disabled(p)) {
542 ap->flags &= ~KPROBE_FLAG_DISABLED;
543 if (!kprobes_all_disarmed)
544 /* Arm the breakpoint again. */
Masami Hiramatsu201517a2009-05-07 16:31:26 -0400545 arm_kprobe(ap);
Masami Hiramatsude5bd882009-04-06 19:01:02 -0700546 }
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700547 return 0;
548}
549
550/*
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700551 * Fill in the required fields of the "manager kprobe". Replace the
552 * earlier kprobe in the hlist with the manager kprobe
553 */
554static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
555{
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700556 copy_kprobe(p, ap);
bibo, maoa9ad9652006-07-30 03:03:26 -0700557 flush_insn_slot(ap);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700558 ap->addr = p->addr;
Masami Hiramatsub918e5e2009-04-06 19:00:58 -0700559 ap->flags = p->flags;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700560 ap->pre_handler = aggr_pre_handler;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700561 ap->fault_handler = aggr_fault_handler;
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800562 /* We don't care the kprobe which has gone. */
563 if (p->post_handler && !kprobe_gone(p))
mao, bibo36721652006-06-26 00:25:22 -0700564 ap->post_handler = aggr_post_handler;
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800565 if (p->break_handler && !kprobe_gone(p))
mao, bibo36721652006-06-26 00:25:22 -0700566 ap->break_handler = aggr_break_handler;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700567
568 INIT_LIST_HEAD(&ap->list);
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800569 list_add_rcu(&p->list, &ap->list);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700570
Keshavamurthy Anil Sadad0f32005-12-12 00:37:12 -0800571 hlist_replace_rcu(&p->hlist, &ap->hlist);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700572}
573
574/*
575 * This is the second or subsequent kprobe at the address - handle
576 * the intricacies
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700577 */
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700578static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
579 struct kprobe *p)
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700580{
581 int ret = 0;
Masami Hiramatsub918e5e2009-04-06 19:00:58 -0700582 struct kprobe *ap = old_p;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700583
Masami Hiramatsub918e5e2009-04-06 19:00:58 -0700584 if (old_p->pre_handler != aggr_pre_handler) {
585 /* If old_p is not an aggr_probe, create new aggr_kprobe. */
586 ap = kzalloc(sizeof(struct kprobe), GFP_KERNEL);
587 if (!ap)
588 return -ENOMEM;
589 add_aggr_kprobe(ap, old_p);
590 }
591
592 if (kprobe_gone(ap)) {
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800593 /*
594 * Attempting to insert new probe at the same location that
595 * had a probe in the module vaddr area which already
596 * freed. So, the instruction slot has already been
597 * released. We need a new slot for the new probe.
598 */
Masami Hiramatsub918e5e2009-04-06 19:00:58 -0700599 ret = arch_prepare_kprobe(ap);
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800600 if (ret)
Masami Hiramatsub918e5e2009-04-06 19:00:58 -0700601 /*
602 * Even if fail to allocate new slot, don't need to
603 * free aggr_probe. It will be used next time, or
604 * freed by unregister_kprobe.
605 */
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800606 return ret;
Masami Hiramatsude5bd882009-04-06 19:01:02 -0700607
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800608 /*
Masami Hiramatsude5bd882009-04-06 19:01:02 -0700609 * Clear gone flag to prevent allocating new slot again, and
610 * set disabled flag because it is not armed yet.
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800611 */
Masami Hiramatsude5bd882009-04-06 19:01:02 -0700612 ap->flags = (ap->flags & ~KPROBE_FLAG_GONE)
613 | KPROBE_FLAG_DISABLED;
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800614 }
Masami Hiramatsub918e5e2009-04-06 19:00:58 -0700615
616 copy_kprobe(ap, p);
617 return add_new_kprobe(ap, p);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700618}
619
Masami Hiramatsude5bd882009-04-06 19:01:02 -0700620/* Try to disable aggr_kprobe, and return 1 if succeeded.*/
621static int __kprobes try_to_disable_aggr_kprobe(struct kprobe *p)
622{
623 struct kprobe *kp;
624
625 list_for_each_entry_rcu(kp, &p->list, list) {
626 if (!kprobe_disabled(kp))
627 /*
628 * There is an active probe on the list.
629 * We can't disable aggr_kprobe.
630 */
631 return 0;
632 }
633 p->flags |= KPROBE_FLAG_DISABLED;
634 return 1;
635}
636
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700637static int __kprobes in_kprobes_functions(unsigned long addr)
638{
Srinivasa Ds3d8d9962008-04-28 02:14:26 -0700639 struct kprobe_blackpoint *kb;
640
Christoph Hellwig6f716ac2007-05-08 00:34:13 -0700641 if (addr >= (unsigned long)__kprobes_text_start &&
642 addr < (unsigned long)__kprobes_text_end)
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700643 return -EINVAL;
Srinivasa Ds3d8d9962008-04-28 02:14:26 -0700644 /*
645 * If there exists a kprobe_blacklist, verify and
646 * fail any probe registration in the prohibited area
647 */
648 for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
649 if (kb->start_addr) {
650 if (addr >= kb->start_addr &&
651 addr < (kb->start_addr + kb->range))
652 return -EINVAL;
653 }
654 }
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700655 return 0;
656}
657
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -0800658/*
659 * If we have a symbol_name argument, look it up and add the offset field
660 * to it. This way, we can specify a relative address to a symbol.
661 */
662static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p)
663{
664 kprobe_opcode_t *addr = p->addr;
665 if (p->symbol_name) {
666 if (addr)
667 return NULL;
668 kprobe_lookup_name(p->symbol_name, addr);
669 }
670
671 if (!addr)
672 return NULL;
673 return (kprobe_opcode_t *)(((char *)addr) + p->offset);
674}
675
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -0800676int __kprobes register_kprobe(struct kprobe *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677{
678 int ret = 0;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700679 struct kprobe *old_p;
Keshavamurthy Anil Sdf019b12006-01-11 12:17:41 -0800680 struct module *probed_mod;
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -0800681 kprobe_opcode_t *addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -0800683 addr = kprobe_addr(p);
684 if (!addr)
Ananth N Mavinakayanahalli3a872d82006-10-02 02:17:30 -0700685 return -EINVAL;
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -0800686 p->addr = addr;
Ananth N Mavinakayanahalli3a872d82006-10-02 02:17:30 -0700687
Masami Hiramatsua189d032008-11-12 13:26:51 -0800688 preempt_disable();
Masami Hiramatsuec30c5f2009-07-28 19:47:23 -0400689 if (!kernel_text_address((unsigned long) p->addr) ||
Masami Hiramatsua189d032008-11-12 13:26:51 -0800690 in_kprobes_functions((unsigned long) p->addr)) {
691 preempt_enable();
Mao, Bibob3e55c72005-12-12 00:37:00 -0800692 return -EINVAL;
Masami Hiramatsua189d032008-11-12 13:26:51 -0800693 }
Mao, Bibob3e55c72005-12-12 00:37:00 -0800694
Masami Hiramatsude5bd882009-04-06 19:01:02 -0700695 /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
696 p->flags &= KPROBE_FLAG_DISABLED;
697
Christoph Hellwig6f716ac2007-05-08 00:34:13 -0700698 /*
699 * Check if are we probing a module.
700 */
Masami Hiramatsua189d032008-11-12 13:26:51 -0800701 probed_mod = __module_text_address((unsigned long) p->addr);
Christoph Hellwig6f716ac2007-05-08 00:34:13 -0700702 if (probed_mod) {
Christoph Hellwig6f716ac2007-05-08 00:34:13 -0700703 /*
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800704 * We must hold a refcount of the probed module while updating
705 * its code to prohibit unexpected unloading.
Keshavamurthy Anil Sdf019b12006-01-11 12:17:41 -0800706 */
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -0800707 if (unlikely(!try_module_get(probed_mod))) {
708 preempt_enable();
709 return -EINVAL;
710 }
Masami Hiramatsuf24659d2009-01-06 14:41:55 -0800711 /*
712 * If the module freed .init.text, we couldn't insert
713 * kprobes in there.
714 */
715 if (within_module_init((unsigned long)p->addr, probed_mod) &&
716 probed_mod->state != MODULE_STATE_COMING) {
717 module_put(probed_mod);
718 preempt_enable();
719 return -EINVAL;
720 }
Keshavamurthy Anil Sdf019b12006-01-11 12:17:41 -0800721 }
Masami Hiramatsua189d032008-11-12 13:26:51 -0800722 preempt_enable();
Mao, Bibob3e55c72005-12-12 00:37:00 -0800723
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800724 p->nmissed = 0;
Masami Hiramatsu98616682008-04-28 02:14:28 -0700725 INIT_LIST_HEAD(&p->list);
Ingo Molnar7a7d1cf2006-03-23 03:00:35 -0800726 mutex_lock(&kprobe_mutex);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700727 old_p = get_kprobe(p->addr);
728 if (old_p) {
729 ret = register_aggr_kprobe(old_p, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 goto out;
731 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732
Mathieu Desnoyers4460fda2009-03-06 10:36:38 -0500733 mutex_lock(&text_mutex);
Christoph Hellwig6f716ac2007-05-08 00:34:13 -0700734 ret = arch_prepare_kprobe(p);
735 if (ret)
Mathieu Desnoyers4460fda2009-03-06 10:36:38 -0500736 goto out_unlock_text;
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -0800737
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700738 INIT_HLIST_NODE(&p->hlist);
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800739 hlist_add_head_rcu(&p->hlist,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740 &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
741
Masami Hiramatsude5bd882009-04-06 19:01:02 -0700742 if (!kprobes_all_disarmed && !kprobe_disabled(p))
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -0700743 arch_arm_kprobe(p);
Christoph Hellwig74a0b572007-10-16 01:24:07 -0700744
Mathieu Desnoyers4460fda2009-03-06 10:36:38 -0500745out_unlock_text:
746 mutex_unlock(&text_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747out:
Ingo Molnar7a7d1cf2006-03-23 03:00:35 -0800748 mutex_unlock(&kprobe_mutex);
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -0800749
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800750 if (probed_mod)
Keshavamurthy Anil Sdf019b12006-01-11 12:17:41 -0800751 module_put(probed_mod);
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800752
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753 return ret;
754}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -0700755EXPORT_SYMBOL_GPL(register_kprobe);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700756
Masami Hiramatsude5bd882009-04-06 19:01:02 -0700757/* Check passed kprobe is valid and return kprobe in kprobe_table. */
758static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p)
759{
760 struct kprobe *old_p, *list_p;
761
762 old_p = get_kprobe(p->addr);
763 if (unlikely(!old_p))
764 return NULL;
765
766 if (p != old_p) {
767 list_for_each_entry_rcu(list_p, &old_p->list, list)
768 if (list_p == p)
769 /* kprobe p is a valid probe */
770 goto valid;
771 return NULL;
772 }
773valid:
774 return old_p;
775}
776
Masami Hiramatsu98616682008-04-28 02:14:28 -0700777/*
778 * Unregister a kprobe without a scheduler synchronization.
779 */
780static int __kprobes __unregister_kprobe_top(struct kprobe *p)
Keshavamurthy Anil Sdf019b12006-01-11 12:17:41 -0800781{
Keshavamurthy Anil Sf709b122006-01-09 20:52:44 -0800782 struct kprobe *old_p, *list_p;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700783
Masami Hiramatsude5bd882009-04-06 19:01:02 -0700784 old_p = __get_valid_kprobe(p);
785 if (old_p == NULL)
Masami Hiramatsu98616682008-04-28 02:14:28 -0700786 return -EINVAL;
787
Christoph Hellwig6f716ac2007-05-08 00:34:13 -0700788 if (old_p == p ||
789 (old_p->pre_handler == aggr_pre_handler &&
Masami Hiramatsu98616682008-04-28 02:14:28 -0700790 list_is_singular(&old_p->list))) {
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -0700791 /*
792 * Only probe on the hash list. Disarm only if kprobes are
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800793 * enabled and not gone - otherwise, the breakpoint would
794 * already have been removed. We save on flushing icache.
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -0700795 */
Masami Hiramatsu201517a2009-05-07 16:31:26 -0400796 if (!kprobes_all_disarmed && !kprobe_disabled(old_p))
797 disarm_kprobe(p);
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -0800798 hlist_del_rcu(&old_p->hlist);
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -0800799 } else {
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800800 if (p->break_handler && !kprobe_gone(p))
Masami Hiramatsu98616682008-04-28 02:14:28 -0700801 old_p->break_handler = NULL;
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800802 if (p->post_handler && !kprobe_gone(p)) {
Masami Hiramatsu98616682008-04-28 02:14:28 -0700803 list_for_each_entry_rcu(list_p, &old_p->list, list) {
804 if ((list_p != p) && (list_p->post_handler))
805 goto noclean;
806 }
807 old_p->post_handler = NULL;
808 }
809noclean:
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -0800810 list_del_rcu(&p->list);
Masami Hiramatsude5bd882009-04-06 19:01:02 -0700811 if (!kprobe_disabled(old_p)) {
812 try_to_disable_aggr_kprobe(old_p);
813 if (!kprobes_all_disarmed && kprobe_disabled(old_p))
Masami Hiramatsu201517a2009-05-07 16:31:26 -0400814 disarm_kprobe(old_p);
Masami Hiramatsude5bd882009-04-06 19:01:02 -0700815 }
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -0800816 }
Masami Hiramatsu98616682008-04-28 02:14:28 -0700817 return 0;
818}
Mao, Bibob3e55c72005-12-12 00:37:00 -0800819
Masami Hiramatsu98616682008-04-28 02:14:28 -0700820static void __kprobes __unregister_kprobe_bottom(struct kprobe *p)
821{
Masami Hiramatsu98616682008-04-28 02:14:28 -0700822 struct kprobe *old_p;
Mao, Bibob3e55c72005-12-12 00:37:00 -0800823
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800824 if (list_empty(&p->list))
Ananth N Mavinakayanahalli0498b632006-01-09 20:52:46 -0800825 arch_remove_kprobe(p);
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800826 else if (list_is_singular(&p->list)) {
827 /* "p" is the last child of an aggr_kprobe */
828 old_p = list_entry(p->list.next, struct kprobe, list);
829 list_del(&p->list);
830 arch_remove_kprobe(old_p);
831 kfree(old_p);
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -0800832 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833}
834
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -0800835int __kprobes register_kprobes(struct kprobe **kps, int num)
Masami Hiramatsu98616682008-04-28 02:14:28 -0700836{
837 int i, ret = 0;
838
839 if (num <= 0)
840 return -EINVAL;
841 for (i = 0; i < num; i++) {
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -0800842 ret = register_kprobe(kps[i]);
Masami Hiramatsu67dddaa2008-06-12 15:21:35 -0700843 if (ret < 0) {
844 if (i > 0)
845 unregister_kprobes(kps, i);
Masami Hiramatsu98616682008-04-28 02:14:28 -0700846 break;
847 }
848 }
849 return ret;
850}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -0700851EXPORT_SYMBOL_GPL(register_kprobes);
Masami Hiramatsu98616682008-04-28 02:14:28 -0700852
Masami Hiramatsu98616682008-04-28 02:14:28 -0700853void __kprobes unregister_kprobe(struct kprobe *p)
854{
855 unregister_kprobes(&p, 1);
856}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -0700857EXPORT_SYMBOL_GPL(unregister_kprobe);
Masami Hiramatsu98616682008-04-28 02:14:28 -0700858
Masami Hiramatsu98616682008-04-28 02:14:28 -0700859void __kprobes unregister_kprobes(struct kprobe **kps, int num)
860{
861 int i;
862
863 if (num <= 0)
864 return;
865 mutex_lock(&kprobe_mutex);
866 for (i = 0; i < num; i++)
867 if (__unregister_kprobe_top(kps[i]) < 0)
868 kps[i]->addr = NULL;
869 mutex_unlock(&kprobe_mutex);
870
871 synchronize_sched();
872 for (i = 0; i < num; i++)
873 if (kps[i]->addr)
874 __unregister_kprobe_bottom(kps[i]);
875}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -0700876EXPORT_SYMBOL_GPL(unregister_kprobes);
Masami Hiramatsu98616682008-04-28 02:14:28 -0700877
Linus Torvalds1da177e2005-04-16 15:20:36 -0700878static struct notifier_block kprobe_exceptions_nb = {
879 .notifier_call = kprobe_exceptions_notify,
Anil S Keshavamurthy3d5631e2006-06-26 00:25:28 -0700880 .priority = 0x7fffffff /* we need to be notified first */
881};
882
Michael Ellerman3d7e3382007-07-19 01:48:11 -0700883unsigned long __weak arch_deref_entry_point(void *entry)
884{
885 return (unsigned long)entry;
886}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -0800888int __kprobes register_jprobes(struct jprobe **jps, int num)
Masami Hiramatsu26b31c12008-04-28 02:14:29 -0700889{
890 struct jprobe *jp;
891 int ret = 0, i;
892
893 if (num <= 0)
894 return -EINVAL;
895 for (i = 0; i < num; i++) {
896 unsigned long addr;
897 jp = jps[i];
898 addr = arch_deref_entry_point(jp->entry);
899
900 if (!kernel_text_address(addr))
901 ret = -EINVAL;
902 else {
903 /* Todo: Verify probepoint is a function entry point */
904 jp->kp.pre_handler = setjmp_pre_handler;
905 jp->kp.break_handler = longjmp_break_handler;
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -0800906 ret = register_kprobe(&jp->kp);
Masami Hiramatsu26b31c12008-04-28 02:14:29 -0700907 }
Masami Hiramatsu67dddaa2008-06-12 15:21:35 -0700908 if (ret < 0) {
909 if (i > 0)
910 unregister_jprobes(jps, i);
Masami Hiramatsu26b31c12008-04-28 02:14:29 -0700911 break;
912 }
913 }
914 return ret;
915}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -0700916EXPORT_SYMBOL_GPL(register_jprobes);
Masami Hiramatsu26b31c12008-04-28 02:14:29 -0700917
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700918int __kprobes register_jprobe(struct jprobe *jp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919{
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -0800920 return register_jprobes(&jp, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700921}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -0700922EXPORT_SYMBOL_GPL(register_jprobe);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700924void __kprobes unregister_jprobe(struct jprobe *jp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700925{
Masami Hiramatsu26b31c12008-04-28 02:14:29 -0700926 unregister_jprobes(&jp, 1);
927}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -0700928EXPORT_SYMBOL_GPL(unregister_jprobe);
Masami Hiramatsu26b31c12008-04-28 02:14:29 -0700929
Masami Hiramatsu26b31c12008-04-28 02:14:29 -0700930void __kprobes unregister_jprobes(struct jprobe **jps, int num)
931{
932 int i;
933
934 if (num <= 0)
935 return;
936 mutex_lock(&kprobe_mutex);
937 for (i = 0; i < num; i++)
938 if (__unregister_kprobe_top(&jps[i]->kp) < 0)
939 jps[i]->kp.addr = NULL;
940 mutex_unlock(&kprobe_mutex);
941
942 synchronize_sched();
943 for (i = 0; i < num; i++) {
944 if (jps[i]->kp.addr)
945 __unregister_kprobe_bottom(&jps[i]->kp);
946 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700947}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -0700948EXPORT_SYMBOL_GPL(unregister_jprobes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700949
Ananth N Mavinakayanahalli9edddaa2008-03-04 14:28:37 -0800950#ifdef CONFIG_KRETPROBES
Adrian Bunke65cefe2006-02-03 03:03:42 -0800951/*
952 * This kprobe pre_handler is registered with every kretprobe. When probe
953 * hits it will set up the return probe.
954 */
955static int __kprobes pre_handler_kretprobe(struct kprobe *p,
956 struct pt_regs *regs)
957{
958 struct kretprobe *rp = container_of(p, struct kretprobe, kp);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700959 unsigned long hash, flags = 0;
960 struct kretprobe_instance *ri;
Adrian Bunke65cefe2006-02-03 03:03:42 -0800961
962 /*TODO: consider to only swap the RA after the last pre_handler fired */
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700963 hash = hash_ptr(current, KPROBE_HASH_BITS);
964 spin_lock_irqsave(&rp->lock, flags);
Christoph Hellwig4c4308c2007-05-08 00:34:14 -0700965 if (!hlist_empty(&rp->free_instances)) {
Christoph Hellwig4c4308c2007-05-08 00:34:14 -0700966 ri = hlist_entry(rp->free_instances.first,
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700967 struct kretprobe_instance, hlist);
968 hlist_del(&ri->hlist);
969 spin_unlock_irqrestore(&rp->lock, flags);
970
Christoph Hellwig4c4308c2007-05-08 00:34:14 -0700971 ri->rp = rp;
972 ri->task = current;
Abhishek Sagarf47cd9b2008-02-06 01:38:22 -0800973
Ananth N Mavinakayanahallif02b8622009-03-18 17:06:21 +0530974 if (rp->entry_handler && rp->entry_handler(ri, regs))
Abhishek Sagarf47cd9b2008-02-06 01:38:22 -0800975 return 0;
Abhishek Sagarf47cd9b2008-02-06 01:38:22 -0800976
Christoph Hellwig4c4308c2007-05-08 00:34:14 -0700977 arch_prepare_kretprobe(ri, regs);
978
979 /* XXX(hch): why is there no hlist_move_head? */
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700980 INIT_HLIST_NODE(&ri->hlist);
981 kretprobe_table_lock(hash, &flags);
982 hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]);
983 kretprobe_table_unlock(hash, &flags);
984 } else {
Christoph Hellwig4c4308c2007-05-08 00:34:14 -0700985 rp->nmissed++;
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700986 spin_unlock_irqrestore(&rp->lock, flags);
987 }
Adrian Bunke65cefe2006-02-03 03:03:42 -0800988 return 0;
989}
990
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -0800991int __kprobes register_kretprobe(struct kretprobe *rp)
Hien Nguyenb94cce92005-06-23 00:09:19 -0700992{
993 int ret = 0;
994 struct kretprobe_instance *inst;
995 int i;
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -0800996 void *addr;
Masami Hiramatsuf438d912007-10-16 01:27:49 -0700997
998 if (kretprobe_blacklist_size) {
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -0800999 addr = kprobe_addr(&rp->kp);
1000 if (!addr)
1001 return -EINVAL;
Masami Hiramatsuf438d912007-10-16 01:27:49 -07001002
1003 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
1004 if (kretprobe_blacklist[i].addr == addr)
1005 return -EINVAL;
1006 }
1007 }
Hien Nguyenb94cce92005-06-23 00:09:19 -07001008
1009 rp->kp.pre_handler = pre_handler_kretprobe;
Ananth N Mavinakayanahalli7522a842006-04-20 02:43:11 -07001010 rp->kp.post_handler = NULL;
1011 rp->kp.fault_handler = NULL;
1012 rp->kp.break_handler = NULL;
Hien Nguyenb94cce92005-06-23 00:09:19 -07001013
1014 /* Pre-allocate memory for max kretprobe instances */
1015 if (rp->maxactive <= 0) {
1016#ifdef CONFIG_PREEMPT
1017 rp->maxactive = max(10, 2 * NR_CPUS);
1018#else
1019 rp->maxactive = NR_CPUS;
1020#endif
1021 }
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001022 spin_lock_init(&rp->lock);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001023 INIT_HLIST_HEAD(&rp->free_instances);
1024 for (i = 0; i < rp->maxactive; i++) {
Abhishek Sagarf47cd9b2008-02-06 01:38:22 -08001025 inst = kmalloc(sizeof(struct kretprobe_instance) +
1026 rp->data_size, GFP_KERNEL);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001027 if (inst == NULL) {
1028 free_rp_inst(rp);
1029 return -ENOMEM;
1030 }
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001031 INIT_HLIST_NODE(&inst->hlist);
1032 hlist_add_head(&inst->hlist, &rp->free_instances);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001033 }
1034
1035 rp->nmissed = 0;
1036 /* Establish function entry probe point */
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -08001037 ret = register_kprobe(&rp->kp);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001038 if (ret != 0)
Hien Nguyenb94cce92005-06-23 00:09:19 -07001039 free_rp_inst(rp);
1040 return ret;
1041}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001042EXPORT_SYMBOL_GPL(register_kretprobe);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001043
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -08001044int __kprobes register_kretprobes(struct kretprobe **rps, int num)
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001045{
1046 int ret = 0, i;
1047
1048 if (num <= 0)
1049 return -EINVAL;
1050 for (i = 0; i < num; i++) {
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -08001051 ret = register_kretprobe(rps[i]);
Masami Hiramatsu67dddaa2008-06-12 15:21:35 -07001052 if (ret < 0) {
1053 if (i > 0)
1054 unregister_kretprobes(rps, i);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001055 break;
1056 }
1057 }
1058 return ret;
1059}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001060EXPORT_SYMBOL_GPL(register_kretprobes);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001061
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001062void __kprobes unregister_kretprobe(struct kretprobe *rp)
1063{
1064 unregister_kretprobes(&rp, 1);
1065}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001066EXPORT_SYMBOL_GPL(unregister_kretprobe);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001067
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001068void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
1069{
1070 int i;
1071
1072 if (num <= 0)
1073 return;
1074 mutex_lock(&kprobe_mutex);
1075 for (i = 0; i < num; i++)
1076 if (__unregister_kprobe_top(&rps[i]->kp) < 0)
1077 rps[i]->kp.addr = NULL;
1078 mutex_unlock(&kprobe_mutex);
1079
1080 synchronize_sched();
1081 for (i = 0; i < num; i++) {
1082 if (rps[i]->kp.addr) {
1083 __unregister_kprobe_bottom(&rps[i]->kp);
1084 cleanup_rp_inst(rps[i]);
1085 }
1086 }
1087}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001088EXPORT_SYMBOL_GPL(unregister_kretprobes);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001089
Ananth N Mavinakayanahalli9edddaa2008-03-04 14:28:37 -08001090#else /* CONFIG_KRETPROBES */
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -07001091int __kprobes register_kretprobe(struct kretprobe *rp)
Hien Nguyenb94cce92005-06-23 00:09:19 -07001092{
1093 return -ENOSYS;
1094}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001095EXPORT_SYMBOL_GPL(register_kretprobe);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001096
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001097int __kprobes register_kretprobes(struct kretprobe **rps, int num)
1098{
1099 return -ENOSYS;
1100}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001101EXPORT_SYMBOL_GPL(register_kretprobes);
1102
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001103void __kprobes unregister_kretprobe(struct kretprobe *rp)
1104{
1105}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001106EXPORT_SYMBOL_GPL(unregister_kretprobe);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001107
1108void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
1109{
1110}
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001111EXPORT_SYMBOL_GPL(unregister_kretprobes);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001112
Srinivasa Ds346fd592007-02-20 13:57:54 -08001113static int __kprobes pre_handler_kretprobe(struct kprobe *p,
1114 struct pt_regs *regs)
1115{
1116 return 0;
1117}
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001118
Ananth N Mavinakayanahalli9edddaa2008-03-04 14:28:37 -08001119#endif /* CONFIG_KRETPROBES */
Hien Nguyenb94cce92005-06-23 00:09:19 -07001120
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001121/* Set the kprobe gone and remove its instruction buffer. */
1122static void __kprobes kill_kprobe(struct kprobe *p)
1123{
1124 struct kprobe *kp;
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001125
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001126 p->flags |= KPROBE_FLAG_GONE;
1127 if (p->pre_handler == aggr_pre_handler) {
1128 /*
1129 * If this is an aggr_kprobe, we have to list all the
1130 * chained probes and mark them GONE.
1131 */
1132 list_for_each_entry_rcu(kp, &p->list, list)
1133 kp->flags |= KPROBE_FLAG_GONE;
1134 p->post_handler = NULL;
1135 p->break_handler = NULL;
1136 }
1137 /*
1138 * Here, we can remove insn_slot safely, because no thread calls
1139 * the original probed function (which will be freed soon) any more.
1140 */
1141 arch_remove_kprobe(p);
1142}
1143
1144/* Module notifier call back, checking kprobes on the module */
1145static int __kprobes kprobes_module_callback(struct notifier_block *nb,
1146 unsigned long val, void *data)
1147{
1148 struct module *mod = data;
1149 struct hlist_head *head;
1150 struct hlist_node *node;
1151 struct kprobe *p;
1152 unsigned int i;
Masami Hiramatsuf24659d2009-01-06 14:41:55 -08001153 int checkcore = (val == MODULE_STATE_GOING);
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001154
Masami Hiramatsuf24659d2009-01-06 14:41:55 -08001155 if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001156 return NOTIFY_DONE;
1157
1158 /*
Masami Hiramatsuf24659d2009-01-06 14:41:55 -08001159 * When MODULE_STATE_GOING was notified, both of module .text and
1160 * .init.text sections would be freed. When MODULE_STATE_LIVE was
1161 * notified, only .init.text section would be freed. We need to
1162 * disable kprobes which have been inserted in the sections.
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001163 */
1164 mutex_lock(&kprobe_mutex);
1165 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1166 head = &kprobe_table[i];
1167 hlist_for_each_entry_rcu(p, node, head, hlist)
Masami Hiramatsuf24659d2009-01-06 14:41:55 -08001168 if (within_module_init((unsigned long)p->addr, mod) ||
1169 (checkcore &&
1170 within_module_core((unsigned long)p->addr, mod))) {
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001171 /*
1172 * The vaddr this probe is installed will soon
1173 * be vfreed buy not synced to disk. Hence,
1174 * disarming the breakpoint isn't needed.
1175 */
1176 kill_kprobe(p);
1177 }
1178 }
1179 mutex_unlock(&kprobe_mutex);
1180 return NOTIFY_DONE;
1181}
1182
1183static struct notifier_block kprobe_module_nb = {
1184 .notifier_call = kprobes_module_callback,
1185 .priority = 0
1186};
1187
Linus Torvalds1da177e2005-04-16 15:20:36 -07001188static int __init init_kprobes(void)
1189{
1190 int i, err = 0;
Srinivasa Ds3d8d9962008-04-28 02:14:26 -07001191 unsigned long offset = 0, size = 0;
1192 char *modname, namebuf[128];
1193 const char *symbol_name;
1194 void *addr;
1195 struct kprobe_blackpoint *kb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001196
1197 /* FIXME allocate the probe table, currently defined statically */
1198 /* initialize all list heads */
Hien Nguyenb94cce92005-06-23 00:09:19 -07001199 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001200 INIT_HLIST_HEAD(&kprobe_table[i]);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001201 INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001202 spin_lock_init(&(kretprobe_table_locks[i].lock));
Hien Nguyenb94cce92005-06-23 00:09:19 -07001203 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204
Srinivasa Ds3d8d9962008-04-28 02:14:26 -07001205 /*
1206 * Lookup and populate the kprobe_blacklist.
1207 *
1208 * Unlike the kretprobe blacklist, we'll need to determine
1209 * the range of addresses that belong to the said functions,
1210 * since a kprobe need not necessarily be at the beginning
1211 * of a function.
1212 */
1213 for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
1214 kprobe_lookup_name(kb->name, addr);
1215 if (!addr)
1216 continue;
1217
1218 kb->start_addr = (unsigned long)addr;
1219 symbol_name = kallsyms_lookup(kb->start_addr,
1220 &size, &offset, &modname, namebuf);
1221 if (!symbol_name)
1222 kb->range = 0;
1223 else
1224 kb->range = size;
1225 }
1226
Masami Hiramatsuf438d912007-10-16 01:27:49 -07001227 if (kretprobe_blacklist_size) {
1228 /* lookup the function address from its name */
1229 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
1230 kprobe_lookup_name(kretprobe_blacklist[i].name,
1231 kretprobe_blacklist[i].addr);
1232 if (!kretprobe_blacklist[i].addr)
1233 printk("kretprobe: lookup failed: %s\n",
1234 kretprobe_blacklist[i].name);
1235 }
1236 }
1237
Masami Hiramatsue579abe2009-04-06 19:01:01 -07001238 /* By default, kprobes are armed */
1239 kprobes_all_disarmed = false;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001240
Rusty Lynch67729262005-07-05 18:54:50 -07001241 err = arch_init_kprobes();
Rusty Lynch802eae72005-06-27 15:17:08 -07001242 if (!err)
1243 err = register_die_notifier(&kprobe_exceptions_nb);
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001244 if (!err)
1245 err = register_module_notifier(&kprobe_module_nb);
1246
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001247 kprobes_initialized = (err == 0);
Rusty Lynch802eae72005-06-27 15:17:08 -07001248
Ananth N Mavinakayanahalli8c1c9352008-01-30 13:32:53 +01001249 if (!err)
1250 init_test_probes();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001251 return err;
1252}
1253
Srinivasa Ds346fd592007-02-20 13:57:54 -08001254#ifdef CONFIG_DEBUG_FS
1255static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p,
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001256 const char *sym, int offset,char *modname)
Srinivasa Ds346fd592007-02-20 13:57:54 -08001257{
1258 char *kprobe_type;
1259
1260 if (p->pre_handler == pre_handler_kretprobe)
1261 kprobe_type = "r";
1262 else if (p->pre_handler == setjmp_pre_handler)
1263 kprobe_type = "j";
1264 else
1265 kprobe_type = "k";
1266 if (sym)
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001267 seq_printf(pi, "%p %s %s+0x%x %s %s%s\n",
1268 p->addr, kprobe_type, sym, offset,
1269 (modname ? modname : " "),
1270 (kprobe_gone(p) ? "[GONE]" : ""),
1271 ((kprobe_disabled(p) && !kprobe_gone(p)) ?
1272 "[DISABLED]" : ""));
Srinivasa Ds346fd592007-02-20 13:57:54 -08001273 else
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001274 seq_printf(pi, "%p %s %p %s%s\n",
1275 p->addr, kprobe_type, p->addr,
1276 (kprobe_gone(p) ? "[GONE]" : ""),
1277 ((kprobe_disabled(p) && !kprobe_gone(p)) ?
1278 "[DISABLED]" : ""));
Srinivasa Ds346fd592007-02-20 13:57:54 -08001279}
1280
1281static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos)
1282{
1283 return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
1284}
1285
1286static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
1287{
1288 (*pos)++;
1289 if (*pos >= KPROBE_TABLE_SIZE)
1290 return NULL;
1291 return pos;
1292}
1293
1294static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v)
1295{
1296 /* Nothing to do */
1297}
1298
1299static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v)
1300{
1301 struct hlist_head *head;
1302 struct hlist_node *node;
1303 struct kprobe *p, *kp;
1304 const char *sym = NULL;
1305 unsigned int i = *(loff_t *) v;
Alexey Dobriyanffb45122007-05-08 00:28:41 -07001306 unsigned long offset = 0;
Srinivasa Ds346fd592007-02-20 13:57:54 -08001307 char *modname, namebuf[128];
1308
1309 head = &kprobe_table[i];
1310 preempt_disable();
1311 hlist_for_each_entry_rcu(p, node, head, hlist) {
Alexey Dobriyanffb45122007-05-08 00:28:41 -07001312 sym = kallsyms_lookup((unsigned long)p->addr, NULL,
Srinivasa Ds346fd592007-02-20 13:57:54 -08001313 &offset, &modname, namebuf);
1314 if (p->pre_handler == aggr_pre_handler) {
1315 list_for_each_entry_rcu(kp, &p->list, list)
1316 report_probe(pi, kp, sym, offset, modname);
1317 } else
1318 report_probe(pi, p, sym, offset, modname);
1319 }
1320 preempt_enable();
1321 return 0;
1322}
1323
James Morris88e9d342009-09-22 16:43:43 -07001324static const struct seq_operations kprobes_seq_ops = {
Srinivasa Ds346fd592007-02-20 13:57:54 -08001325 .start = kprobe_seq_start,
1326 .next = kprobe_seq_next,
1327 .stop = kprobe_seq_stop,
1328 .show = show_kprobe_addr
1329};
1330
1331static int __kprobes kprobes_open(struct inode *inode, struct file *filp)
1332{
1333 return seq_open(filp, &kprobes_seq_ops);
1334}
1335
1336static struct file_operations debugfs_kprobes_operations = {
1337 .open = kprobes_open,
1338 .read = seq_read,
1339 .llseek = seq_lseek,
1340 .release = seq_release,
1341};
1342
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001343/* Disable one kprobe */
1344int __kprobes disable_kprobe(struct kprobe *kp)
1345{
1346 int ret = 0;
1347 struct kprobe *p;
1348
1349 mutex_lock(&kprobe_mutex);
1350
1351 /* Check whether specified probe is valid. */
1352 p = __get_valid_kprobe(kp);
1353 if (unlikely(p == NULL)) {
1354 ret = -EINVAL;
1355 goto out;
1356 }
1357
1358 /* If the probe is already disabled (or gone), just return */
1359 if (kprobe_disabled(kp))
1360 goto out;
1361
1362 kp->flags |= KPROBE_FLAG_DISABLED;
1363 if (p != kp)
1364 /* When kp != p, p is always enabled. */
1365 try_to_disable_aggr_kprobe(p);
1366
1367 if (!kprobes_all_disarmed && kprobe_disabled(p))
Masami Hiramatsu201517a2009-05-07 16:31:26 -04001368 disarm_kprobe(p);
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001369out:
1370 mutex_unlock(&kprobe_mutex);
1371 return ret;
1372}
1373EXPORT_SYMBOL_GPL(disable_kprobe);
1374
1375/* Enable one kprobe */
1376int __kprobes enable_kprobe(struct kprobe *kp)
1377{
1378 int ret = 0;
1379 struct kprobe *p;
1380
1381 mutex_lock(&kprobe_mutex);
1382
1383 /* Check whether specified probe is valid. */
1384 p = __get_valid_kprobe(kp);
1385 if (unlikely(p == NULL)) {
1386 ret = -EINVAL;
1387 goto out;
1388 }
1389
1390 if (kprobe_gone(kp)) {
1391 /* This kprobe has gone, we couldn't enable it. */
1392 ret = -EINVAL;
1393 goto out;
1394 }
1395
1396 if (!kprobes_all_disarmed && kprobe_disabled(p))
Masami Hiramatsu201517a2009-05-07 16:31:26 -04001397 arm_kprobe(p);
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001398
1399 p->flags &= ~KPROBE_FLAG_DISABLED;
1400 if (p != kp)
1401 kp->flags &= ~KPROBE_FLAG_DISABLED;
1402out:
1403 mutex_unlock(&kprobe_mutex);
1404 return ret;
1405}
1406EXPORT_SYMBOL_GPL(enable_kprobe);
1407
Masami Hiramatsue579abe2009-04-06 19:01:01 -07001408static void __kprobes arm_all_kprobes(void)
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001409{
1410 struct hlist_head *head;
1411 struct hlist_node *node;
1412 struct kprobe *p;
1413 unsigned int i;
1414
1415 mutex_lock(&kprobe_mutex);
1416
Masami Hiramatsue579abe2009-04-06 19:01:01 -07001417 /* If kprobes are armed, just return */
1418 if (!kprobes_all_disarmed)
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001419 goto already_enabled;
1420
Mathieu Desnoyers4460fda2009-03-06 10:36:38 -05001421 mutex_lock(&text_mutex);
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001422 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1423 head = &kprobe_table[i];
1424 hlist_for_each_entry_rcu(p, node, head, hlist)
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001425 if (!kprobe_disabled(p))
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001426 arch_arm_kprobe(p);
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001427 }
Mathieu Desnoyers4460fda2009-03-06 10:36:38 -05001428 mutex_unlock(&text_mutex);
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001429
Masami Hiramatsue579abe2009-04-06 19:01:01 -07001430 kprobes_all_disarmed = false;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001431 printk(KERN_INFO "Kprobes globally enabled\n");
1432
1433already_enabled:
1434 mutex_unlock(&kprobe_mutex);
1435 return;
1436}
1437
Masami Hiramatsue579abe2009-04-06 19:01:01 -07001438static void __kprobes disarm_all_kprobes(void)
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001439{
1440 struct hlist_head *head;
1441 struct hlist_node *node;
1442 struct kprobe *p;
1443 unsigned int i;
1444
1445 mutex_lock(&kprobe_mutex);
1446
Masami Hiramatsue579abe2009-04-06 19:01:01 -07001447 /* If kprobes are already disarmed, just return */
1448 if (kprobes_all_disarmed)
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001449 goto already_disabled;
1450
Masami Hiramatsue579abe2009-04-06 19:01:01 -07001451 kprobes_all_disarmed = true;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001452 printk(KERN_INFO "Kprobes globally disabled\n");
Mathieu Desnoyers4460fda2009-03-06 10:36:38 -05001453 mutex_lock(&text_mutex);
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001454 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1455 head = &kprobe_table[i];
1456 hlist_for_each_entry_rcu(p, node, head, hlist) {
Masami Hiramatsude5bd882009-04-06 19:01:02 -07001457 if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p))
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001458 arch_disarm_kprobe(p);
1459 }
1460 }
1461
Mathieu Desnoyers4460fda2009-03-06 10:36:38 -05001462 mutex_unlock(&text_mutex);
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001463 mutex_unlock(&kprobe_mutex);
1464 /* Allow all currently running kprobes to complete */
1465 synchronize_sched();
Christoph Hellwig74a0b572007-10-16 01:24:07 -07001466 return;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001467
1468already_disabled:
1469 mutex_unlock(&kprobe_mutex);
1470 return;
1471}
1472
1473/*
1474 * XXX: The debugfs bool file interface doesn't allow for callbacks
1475 * when the bool state is switched. We can reuse that facility when
1476 * available
1477 */
1478static ssize_t read_enabled_file_bool(struct file *file,
1479 char __user *user_buf, size_t count, loff_t *ppos)
1480{
1481 char buf[3];
1482
Masami Hiramatsue579abe2009-04-06 19:01:01 -07001483 if (!kprobes_all_disarmed)
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001484 buf[0] = '1';
1485 else
1486 buf[0] = '0';
1487 buf[1] = '\n';
1488 buf[2] = 0x00;
1489 return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
1490}
1491
1492static ssize_t write_enabled_file_bool(struct file *file,
1493 const char __user *user_buf, size_t count, loff_t *ppos)
1494{
1495 char buf[32];
1496 int buf_size;
1497
1498 buf_size = min(count, (sizeof(buf)-1));
1499 if (copy_from_user(buf, user_buf, buf_size))
1500 return -EFAULT;
1501
1502 switch (buf[0]) {
1503 case 'y':
1504 case 'Y':
1505 case '1':
Masami Hiramatsue579abe2009-04-06 19:01:01 -07001506 arm_all_kprobes();
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001507 break;
1508 case 'n':
1509 case 'N':
1510 case '0':
Masami Hiramatsue579abe2009-04-06 19:01:01 -07001511 disarm_all_kprobes();
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001512 break;
1513 }
1514
1515 return count;
1516}
1517
1518static struct file_operations fops_kp = {
1519 .read = read_enabled_file_bool,
1520 .write = write_enabled_file_bool,
1521};
1522
Srinivasa Ds346fd592007-02-20 13:57:54 -08001523static int __kprobes debugfs_kprobe_init(void)
1524{
1525 struct dentry *dir, *file;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001526 unsigned int value = 1;
Srinivasa Ds346fd592007-02-20 13:57:54 -08001527
1528 dir = debugfs_create_dir("kprobes", NULL);
1529 if (!dir)
1530 return -ENOMEM;
1531
Randy Dunlape3869792007-05-08 00:27:01 -07001532 file = debugfs_create_file("list", 0444, dir, NULL,
Srinivasa Ds346fd592007-02-20 13:57:54 -08001533 &debugfs_kprobes_operations);
1534 if (!file) {
1535 debugfs_remove(dir);
1536 return -ENOMEM;
1537 }
1538
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001539 file = debugfs_create_file("enabled", 0600, dir,
1540 &value, &fops_kp);
1541 if (!file) {
1542 debugfs_remove(dir);
1543 return -ENOMEM;
1544 }
1545
Srinivasa Ds346fd592007-02-20 13:57:54 -08001546 return 0;
1547}
1548
1549late_initcall(debugfs_kprobe_init);
1550#endif /* CONFIG_DEBUG_FS */
1551
1552module_init(init_kprobes);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001553
Masami Hiramatsu99081ab2009-04-06 19:00:59 -07001554/* defined in arch/.../kernel/kprobes.c */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001555EXPORT_SYMBOL_GPL(jprobe_return);