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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>
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -070046
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -070047#include <asm-generic/sections.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070048#include <asm/cacheflush.h>
49#include <asm/errno.h>
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -070050#include <asm/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070051
52#define KPROBE_HASH_BITS 6
53#define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
54
Ananth N Mavinakayanahalli3a872d82006-10-02 02:17:30 -070055
56/*
57 * Some oddball architectures like 64bit powerpc have function descriptors
58 * so this must be overridable.
59 */
60#ifndef kprobe_lookup_name
61#define kprobe_lookup_name(name, addr) \
62 addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name)))
63#endif
64
Srinivasa D Sef53d9c2008-07-25 01:46:04 -070065static int kprobes_initialized;
Linus Torvalds1da177e2005-04-16 15:20:36 -070066static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
Hien Nguyenb94cce92005-06-23 00:09:19 -070067static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
Linus Torvalds1da177e2005-04-16 15:20:36 -070068
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -070069/* NOTE: change this value only with kprobe_mutex held */
70static bool kprobe_enabled;
71
Masami Hiramatsu12941562009-01-06 14:41:50 -080072static DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -080073static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
Srinivasa D Sef53d9c2008-07-25 01:46:04 -070074static struct {
Andrew Morton7e036d02008-11-12 13:26:57 -080075 spinlock_t lock ____cacheline_aligned_in_smp;
Srinivasa D Sef53d9c2008-07-25 01:46:04 -070076} kretprobe_table_locks[KPROBE_TABLE_SIZE];
77
78static spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
79{
80 return &(kretprobe_table_locks[hash].lock);
81}
Linus Torvalds1da177e2005-04-16 15:20:36 -070082
Srinivasa Ds3d8d9962008-04-28 02:14:26 -070083/*
84 * Normally, functions that we'd want to prohibit kprobes in, are marked
85 * __kprobes. But, there are cases where such functions already belong to
86 * a different section (__sched for preempt_schedule)
87 *
88 * For such cases, we now have a blacklist
89 */
Daniel Guilak544304b2008-07-10 09:38:19 -070090static struct kprobe_blackpoint kprobe_blacklist[] = {
Srinivasa Ds3d8d9962008-04-28 02:14:26 -070091 {"preempt_schedule",},
92 {NULL} /* Terminator */
93};
94
Anil S Keshavamurthy2d14e392006-01-09 20:52:41 -080095#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -070096/*
97 * kprobe->ainsn.insn points to the copy of the instruction to be
98 * single-stepped. x86_64, POWER4 and above have no-exec support and
99 * stepping on the instruction on a vmalloced/kmalloced/data page
100 * is a recipe for disaster
101 */
102#define INSNS_PER_PAGE (PAGE_SIZE/(MAX_INSN_SIZE * sizeof(kprobe_opcode_t)))
103
104struct kprobe_insn_page {
105 struct hlist_node hlist;
106 kprobe_opcode_t *insns; /* Page of instruction slots */
107 char slot_used[INSNS_PER_PAGE];
108 int nused;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800109 int ngarbage;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700110};
111
Masami Hiramatsuab40c5c2007-01-30 14:36:06 -0800112enum kprobe_slot_state {
113 SLOT_CLEAN = 0,
114 SLOT_DIRTY = 1,
115 SLOT_USED = 2,
116};
117
Masami Hiramatsu12941562009-01-06 14:41:50 -0800118static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_pages */
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700119static struct hlist_head kprobe_insn_pages;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800120static int kprobe_garbage_slots;
121static int collect_garbage_slots(void);
122
123static int __kprobes check_safety(void)
124{
125 int ret = 0;
126#if defined(CONFIG_PREEMPT) && defined(CONFIG_PM)
127 ret = freeze_processes();
128 if (ret == 0) {
129 struct task_struct *p, *q;
130 do_each_thread(p, q) {
131 if (p != current && p->state == TASK_RUNNING &&
132 p->pid != 0) {
133 printk("Check failed: %s is running\n",p->comm);
134 ret = -1;
135 goto loop_end;
136 }
137 } while_each_thread(p, q);
138 }
139loop_end:
140 thaw_processes();
141#else
142 synchronize_sched();
143#endif
144 return ret;
145}
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700146
147/**
Masami Hiramatsu12941562009-01-06 14:41:50 -0800148 * __get_insn_slot() - Find a slot on an executable page for an instruction.
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700149 * We allocate an executable page if there's no room on existing ones.
150 */
Masami Hiramatsu12941562009-01-06 14:41:50 -0800151static kprobe_opcode_t __kprobes *__get_insn_slot(void)
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700152{
153 struct kprobe_insn_page *kip;
154 struct hlist_node *pos;
155
Christoph Hellwig6f716ac2007-05-08 00:34:13 -0700156 retry:
Christoph Hellwigb0bb5012007-05-08 00:34:11 -0700157 hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) {
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 }
191 INIT_HLIST_NODE(&kip->hlist);
192 hlist_add_head(&kip->hlist, &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 */
221 hlist_del(&kip->hlist);
222 if (hlist_empty(&kprobe_insn_pages)) {
223 INIT_HLIST_NODE(&kip->hlist);
224 hlist_add_head(&kip->hlist,
225 &kprobe_insn_pages);
226 } else {
227 module_free(NULL, kip->insns);
228 kfree(kip);
229 }
230 return 1;
231 }
232 return 0;
233}
234
235static int __kprobes collect_garbage_slots(void)
236{
237 struct kprobe_insn_page *kip;
238 struct hlist_node *pos, *next;
Masami Hiramatsu12941562009-01-06 14:41:50 -0800239 int safety;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800240
241 /* Ensure no-one is preepmted on the garbages */
Masami Hiramatsu12941562009-01-06 14:41:50 -0800242 mutex_unlock(&kprobe_insn_mutex);
243 safety = check_safety();
244 mutex_lock(&kprobe_insn_mutex);
245 if (safety != 0)
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800246 return -EAGAIN;
247
Christoph Hellwigb0bb5012007-05-08 00:34:11 -0700248 hlist_for_each_entry_safe(kip, pos, next, &kprobe_insn_pages, hlist) {
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800249 int i;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800250 if (kip->ngarbage == 0)
251 continue;
252 kip->ngarbage = 0; /* we will collect all garbages */
253 for (i = 0; i < INSNS_PER_PAGE; i++) {
Masami Hiramatsuab40c5c2007-01-30 14:36:06 -0800254 if (kip->slot_used[i] == SLOT_DIRTY &&
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800255 collect_one_slot(kip, i))
256 break;
257 }
258 }
259 kprobe_garbage_slots = 0;
260 return 0;
261}
262
263void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700264{
265 struct kprobe_insn_page *kip;
266 struct hlist_node *pos;
267
Masami Hiramatsu12941562009-01-06 14:41:50 -0800268 mutex_lock(&kprobe_insn_mutex);
Christoph Hellwigb0bb5012007-05-08 00:34:11 -0700269 hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) {
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700270 if (kip->insns <= slot &&
271 slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) {
272 int i = (slot - kip->insns) / MAX_INSN_SIZE;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800273 if (dirty) {
Masami Hiramatsuab40c5c2007-01-30 14:36:06 -0800274 kip->slot_used[i] = SLOT_DIRTY;
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800275 kip->ngarbage++;
276 } else {
277 collect_one_slot(kip, i);
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700278 }
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800279 break;
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700280 }
281 }
Christoph Hellwig6f716ac2007-05-08 00:34:13 -0700282
283 if (dirty && ++kprobe_garbage_slots > INSNS_PER_PAGE)
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800284 collect_garbage_slots();
Masami Hiramatsu12941562009-01-06 14:41:50 -0800285
286 mutex_unlock(&kprobe_insn_mutex);
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700287}
Anil S Keshavamurthy2d14e392006-01-09 20:52:41 -0800288#endif
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700289
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800290/* We have preemption disabled.. so it is safe to use __ versions */
291static inline void set_kprobe_instance(struct kprobe *kp)
292{
293 __get_cpu_var(kprobe_instance) = kp;
294}
295
296static inline void reset_kprobe_instance(void)
297{
298 __get_cpu_var(kprobe_instance) = NULL;
299}
300
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800301/*
302 * This routine is called either:
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -0800303 * - under the kprobe_mutex - during kprobe_[un]register()
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800304 * OR
Ananth N Mavinakayanahallid217d542005-11-07 01:00:14 -0800305 * - with preemption disabled - from arch/xxx/kernel/kprobes.c
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800306 */
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700307struct kprobe __kprobes *get_kprobe(void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308{
309 struct hlist_head *head;
310 struct hlist_node *node;
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800311 struct kprobe *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312
313 head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800314 hlist_for_each_entry_rcu(p, node, head, hlist) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 if (p->addr == addr)
316 return p;
317 }
318 return NULL;
319}
320
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700321/*
322 * Aggregate handlers for multiple kprobes support - these handlers
323 * take care of invoking the individual kprobe handlers on p->list
324 */
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700325static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700326{
327 struct kprobe *kp;
328
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800329 list_for_each_entry_rcu(kp, &p->list, list) {
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800330 if (kp->pre_handler && !kprobe_gone(kp)) {
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800331 set_kprobe_instance(kp);
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700332 if (kp->pre_handler(kp, regs))
333 return 1;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700334 }
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800335 reset_kprobe_instance();
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700336 }
337 return 0;
338}
339
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700340static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
341 unsigned long flags)
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700342{
343 struct kprobe *kp;
344
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800345 list_for_each_entry_rcu(kp, &p->list, list) {
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800346 if (kp->post_handler && !kprobe_gone(kp)) {
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800347 set_kprobe_instance(kp);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700348 kp->post_handler(kp, regs, flags);
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800349 reset_kprobe_instance();
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700350 }
351 }
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700352}
353
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700354static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
355 int trapnr)
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700356{
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800357 struct kprobe *cur = __get_cpu_var(kprobe_instance);
358
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700359 /*
360 * if we faulted "during" the execution of a user specified
361 * probe handler, invoke just that probe's fault handler
362 */
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800363 if (cur && cur->fault_handler) {
364 if (cur->fault_handler(cur, regs, trapnr))
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700365 return 1;
366 }
367 return 0;
368}
369
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700370static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700371{
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800372 struct kprobe *cur = __get_cpu_var(kprobe_instance);
373 int ret = 0;
374
375 if (cur && cur->break_handler) {
376 if (cur->break_handler(cur, regs))
377 ret = 1;
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700378 }
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800379 reset_kprobe_instance();
380 return ret;
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700381}
382
Keshavamurthy Anil Sbf8d5c52005-12-12 00:37:34 -0800383/* Walks the list and increments nmissed count for multiprobe case */
384void __kprobes kprobes_inc_nmissed_count(struct kprobe *p)
385{
386 struct kprobe *kp;
387 if (p->pre_handler != aggr_pre_handler) {
388 p->nmissed++;
389 } else {
390 list_for_each_entry_rcu(kp, &p->list, list)
391 kp->nmissed++;
392 }
393 return;
394}
395
bibo,mao99219a32006-10-02 02:17:35 -0700396void __kprobes recycle_rp_inst(struct kretprobe_instance *ri,
397 struct hlist_head *head)
Hien Nguyenb94cce92005-06-23 00:09:19 -0700398{
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700399 struct kretprobe *rp = ri->rp;
400
Hien Nguyenb94cce92005-06-23 00:09:19 -0700401 /* remove rp inst off the rprobe_inst_table */
402 hlist_del(&ri->hlist);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700403 INIT_HLIST_NODE(&ri->hlist);
404 if (likely(rp)) {
405 spin_lock(&rp->lock);
406 hlist_add_head(&ri->hlist, &rp->free_instances);
407 spin_unlock(&rp->lock);
Hien Nguyenb94cce92005-06-23 00:09:19 -0700408 } else
409 /* Unregistering */
bibo,mao99219a32006-10-02 02:17:35 -0700410 hlist_add_head(&ri->hlist, head);
Hien Nguyenb94cce92005-06-23 00:09:19 -0700411}
412
Masami Hiramatsu017c39b2009-01-06 14:41:51 -0800413void __kprobes kretprobe_hash_lock(struct task_struct *tsk,
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700414 struct hlist_head **head, unsigned long *flags)
Hien Nguyenb94cce92005-06-23 00:09:19 -0700415{
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700416 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
417 spinlock_t *hlist_lock;
418
419 *head = &kretprobe_inst_table[hash];
420 hlist_lock = kretprobe_table_lock_ptr(hash);
421 spin_lock_irqsave(hlist_lock, *flags);
422}
423
Masami Hiramatsu017c39b2009-01-06 14:41:51 -0800424static void __kprobes kretprobe_table_lock(unsigned long hash,
425 unsigned long *flags)
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700426{
427 spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
428 spin_lock_irqsave(hlist_lock, *flags);
429}
430
Masami Hiramatsu017c39b2009-01-06 14:41:51 -0800431void __kprobes kretprobe_hash_unlock(struct task_struct *tsk,
432 unsigned long *flags)
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700433{
434 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
435 spinlock_t *hlist_lock;
436
437 hlist_lock = kretprobe_table_lock_ptr(hash);
438 spin_unlock_irqrestore(hlist_lock, *flags);
439}
440
Masami Hiramatsu017c39b2009-01-06 14:41:51 -0800441void __kprobes kretprobe_table_unlock(unsigned long hash, unsigned long *flags)
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700442{
443 spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
444 spin_unlock_irqrestore(hlist_lock, *flags);
Hien Nguyenb94cce92005-06-23 00:09:19 -0700445}
446
Hien Nguyenb94cce92005-06-23 00:09:19 -0700447/*
bibo maoc6fd91f2006-03-26 01:38:20 -0800448 * This function is called from finish_task_switch when task tk becomes dead,
449 * so that we can recycle any function-return probe instances associated
450 * with this task. These left over instances represent probed functions
451 * that have been called but will never return.
Hien Nguyenb94cce92005-06-23 00:09:19 -0700452 */
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700453void __kprobes kprobe_flush_task(struct task_struct *tk)
Hien Nguyenb94cce92005-06-23 00:09:19 -0700454{
bibo,mao62c27be2006-10-02 02:17:33 -0700455 struct kretprobe_instance *ri;
bibo,mao99219a32006-10-02 02:17:35 -0700456 struct hlist_head *head, empty_rp;
Rusty Lynch802eae72005-06-27 15:17:08 -0700457 struct hlist_node *node, *tmp;
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700458 unsigned long hash, flags = 0;
Rusty Lynch802eae72005-06-27 15:17:08 -0700459
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700460 if (unlikely(!kprobes_initialized))
461 /* Early boot. kretprobe_table_locks not yet initialized. */
462 return;
463
464 hash = hash_ptr(tk, KPROBE_HASH_BITS);
465 head = &kretprobe_inst_table[hash];
466 kretprobe_table_lock(hash, &flags);
bibo,mao62c27be2006-10-02 02:17:33 -0700467 hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
468 if (ri->task == tk)
bibo,mao99219a32006-10-02 02:17:35 -0700469 recycle_rp_inst(ri, &empty_rp);
bibo,mao62c27be2006-10-02 02:17:33 -0700470 }
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700471 kretprobe_table_unlock(hash, &flags);
472 INIT_HLIST_HEAD(&empty_rp);
bibo,mao99219a32006-10-02 02:17:35 -0700473 hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
474 hlist_del(&ri->hlist);
475 kfree(ri);
476 }
Hien Nguyenb94cce92005-06-23 00:09:19 -0700477}
478
Hien Nguyenb94cce92005-06-23 00:09:19 -0700479static inline void free_rp_inst(struct kretprobe *rp)
480{
481 struct kretprobe_instance *ri;
Christoph Hellwig4c4308c2007-05-08 00:34:14 -0700482 struct hlist_node *pos, *next;
483
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700484 hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) {
485 hlist_del(&ri->hlist);
Hien Nguyenb94cce92005-06-23 00:09:19 -0700486 kfree(ri);
487 }
488}
489
Masami Hiramatsu4a296e02008-04-28 02:14:29 -0700490static void __kprobes cleanup_rp_inst(struct kretprobe *rp)
491{
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700492 unsigned long flags, hash;
Masami Hiramatsu4a296e02008-04-28 02:14:29 -0700493 struct kretprobe_instance *ri;
494 struct hlist_node *pos, *next;
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700495 struct hlist_head *head;
496
Masami Hiramatsu4a296e02008-04-28 02:14:29 -0700497 /* No race here */
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700498 for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) {
499 kretprobe_table_lock(hash, &flags);
500 head = &kretprobe_inst_table[hash];
501 hlist_for_each_entry_safe(ri, pos, next, head, hlist) {
502 if (ri->rp == rp)
503 ri->rp = NULL;
504 }
505 kretprobe_table_unlock(hash, &flags);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -0700506 }
Masami Hiramatsu4a296e02008-04-28 02:14:29 -0700507 free_rp_inst(rp);
508}
509
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700510/*
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700511 * Keep all fields in the kprobe consistent
512 */
513static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p)
514{
515 memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t));
516 memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn));
517}
518
519/*
520* Add the new probe to old_p->list. Fail if this is the
521* second jprobe at the address - two jprobes can't coexist
522*/
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700523static int __kprobes add_new_kprobe(struct kprobe *old_p, struct kprobe *p)
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700524{
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700525 if (p->break_handler) {
mao, bibo36721652006-06-26 00:25:22 -0700526 if (old_p->break_handler)
527 return -EEXIST;
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800528 list_add_tail_rcu(&p->list, &old_p->list);
mao, bibo36721652006-06-26 00:25:22 -0700529 old_p->break_handler = aggr_break_handler;
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700530 } else
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800531 list_add_rcu(&p->list, &old_p->list);
mao, bibo36721652006-06-26 00:25:22 -0700532 if (p->post_handler && !old_p->post_handler)
533 old_p->post_handler = aggr_post_handler;
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700534 return 0;
535}
536
537/*
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700538 * Fill in the required fields of the "manager kprobe". Replace the
539 * earlier kprobe in the hlist with the manager kprobe
540 */
541static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
542{
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700543 copy_kprobe(p, ap);
bibo, maoa9ad9652006-07-30 03:03:26 -0700544 flush_insn_slot(ap);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700545 ap->addr = p->addr;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700546 ap->pre_handler = aggr_pre_handler;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700547 ap->fault_handler = aggr_fault_handler;
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800548 /* We don't care the kprobe which has gone. */
549 if (p->post_handler && !kprobe_gone(p))
mao, bibo36721652006-06-26 00:25:22 -0700550 ap->post_handler = aggr_post_handler;
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800551 if (p->break_handler && !kprobe_gone(p))
mao, bibo36721652006-06-26 00:25:22 -0700552 ap->break_handler = aggr_break_handler;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700553
554 INIT_LIST_HEAD(&ap->list);
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800555 list_add_rcu(&p->list, &ap->list);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700556
Keshavamurthy Anil Sadad0f32005-12-12 00:37:12 -0800557 hlist_replace_rcu(&p->hlist, &ap->hlist);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700558}
559
560/*
561 * This is the second or subsequent kprobe at the address - handle
562 * the intricacies
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700563 */
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700564static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
565 struct kprobe *p)
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700566{
567 int ret = 0;
568 struct kprobe *ap;
569
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800570 if (kprobe_gone(old_p)) {
571 /*
572 * Attempting to insert new probe at the same location that
573 * had a probe in the module vaddr area which already
574 * freed. So, the instruction slot has already been
575 * released. We need a new slot for the new probe.
576 */
577 ret = arch_prepare_kprobe(old_p);
578 if (ret)
579 return ret;
580 }
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700581 if (old_p->pre_handler == aggr_pre_handler) {
582 copy_kprobe(old_p, p);
583 ret = add_new_kprobe(old_p, p);
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800584 ap = old_p;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700585 } else {
Keshavamurthy Anil Sa0d50062006-01-09 20:52:46 -0800586 ap = kzalloc(sizeof(struct kprobe), GFP_KERNEL);
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800587 if (!ap) {
588 if (kprobe_gone(old_p))
589 arch_remove_kprobe(old_p);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700590 return -ENOMEM;
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800591 }
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700592 add_aggr_kprobe(ap, old_p);
Prasanna S Panchamukhi8b0914e2005-06-23 00:09:41 -0700593 copy_kprobe(ap, p);
594 ret = add_new_kprobe(ap, p);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700595 }
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800596 if (kprobe_gone(old_p)) {
597 /*
598 * If the old_p has gone, its breakpoint has been disarmed.
599 * We have to arm it again after preparing real kprobes.
600 */
601 ap->flags &= ~KPROBE_FLAG_GONE;
602 if (kprobe_enabled)
603 arch_arm_kprobe(ap);
604 }
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700605 return ret;
606}
607
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700608static int __kprobes in_kprobes_functions(unsigned long addr)
609{
Srinivasa Ds3d8d9962008-04-28 02:14:26 -0700610 struct kprobe_blackpoint *kb;
611
Christoph Hellwig6f716ac2007-05-08 00:34:13 -0700612 if (addr >= (unsigned long)__kprobes_text_start &&
613 addr < (unsigned long)__kprobes_text_end)
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700614 return -EINVAL;
Srinivasa Ds3d8d9962008-04-28 02:14:26 -0700615 /*
616 * If there exists a kprobe_blacklist, verify and
617 * fail any probe registration in the prohibited area
618 */
619 for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
620 if (kb->start_addr) {
621 if (addr >= kb->start_addr &&
622 addr < (kb->start_addr + kb->range))
623 return -EINVAL;
624 }
625 }
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700626 return 0;
627}
628
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -0800629/*
630 * If we have a symbol_name argument, look it up and add the offset field
631 * to it. This way, we can specify a relative address to a symbol.
632 */
633static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p)
634{
635 kprobe_opcode_t *addr = p->addr;
636 if (p->symbol_name) {
637 if (addr)
638 return NULL;
639 kprobe_lookup_name(p->symbol_name, addr);
640 }
641
642 if (!addr)
643 return NULL;
644 return (kprobe_opcode_t *)(((char *)addr) + p->offset);
645}
646
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -0800647int __kprobes register_kprobe(struct kprobe *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648{
649 int ret = 0;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700650 struct kprobe *old_p;
Keshavamurthy Anil Sdf019b12006-01-11 12:17:41 -0800651 struct module *probed_mod;
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -0800652 kprobe_opcode_t *addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -0800654 addr = kprobe_addr(p);
655 if (!addr)
Ananth N Mavinakayanahalli3a872d82006-10-02 02:17:30 -0700656 return -EINVAL;
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -0800657 p->addr = addr;
Ananth N Mavinakayanahalli3a872d82006-10-02 02:17:30 -0700658
Masami Hiramatsua189d032008-11-12 13:26:51 -0800659 preempt_disable();
660 if (!__kernel_text_address((unsigned long) p->addr) ||
661 in_kprobes_functions((unsigned long) p->addr)) {
662 preempt_enable();
Mao, Bibob3e55c72005-12-12 00:37:00 -0800663 return -EINVAL;
Masami Hiramatsua189d032008-11-12 13:26:51 -0800664 }
Mao, Bibob3e55c72005-12-12 00:37:00 -0800665
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800666 p->flags = 0;
Christoph Hellwig6f716ac2007-05-08 00:34:13 -0700667 /*
668 * Check if are we probing a module.
669 */
Masami Hiramatsua189d032008-11-12 13:26:51 -0800670 probed_mod = __module_text_address((unsigned long) p->addr);
Christoph Hellwig6f716ac2007-05-08 00:34:13 -0700671 if (probed_mod) {
Christoph Hellwig6f716ac2007-05-08 00:34:13 -0700672 /*
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800673 * We must hold a refcount of the probed module while updating
674 * its code to prohibit unexpected unloading.
Keshavamurthy Anil Sdf019b12006-01-11 12:17:41 -0800675 */
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -0800676 if (unlikely(!try_module_get(probed_mod))) {
677 preempt_enable();
678 return -EINVAL;
679 }
Keshavamurthy Anil Sdf019b12006-01-11 12:17:41 -0800680 }
Masami Hiramatsua189d032008-11-12 13:26:51 -0800681 preempt_enable();
Mao, Bibob3e55c72005-12-12 00:37:00 -0800682
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800683 p->nmissed = 0;
Masami Hiramatsu98616682008-04-28 02:14:28 -0700684 INIT_LIST_HEAD(&p->list);
Ingo Molnar7a7d1cf2006-03-23 03:00:35 -0800685 mutex_lock(&kprobe_mutex);
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700686 old_p = get_kprobe(p->addr);
687 if (old_p) {
688 ret = register_aggr_kprobe(old_p, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689 goto out;
690 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691
Christoph Hellwig6f716ac2007-05-08 00:34:13 -0700692 ret = arch_prepare_kprobe(p);
693 if (ret)
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -0800694 goto out;
695
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700696 INIT_HLIST_NODE(&p->hlist);
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800697 hlist_add_head_rcu(&p->hlist,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698 &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
699
Christoph Hellwig74a0b572007-10-16 01:24:07 -0700700 if (kprobe_enabled)
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -0700701 arch_arm_kprobe(p);
Christoph Hellwig74a0b572007-10-16 01:24:07 -0700702
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703out:
Ingo Molnar7a7d1cf2006-03-23 03:00:35 -0800704 mutex_unlock(&kprobe_mutex);
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -0800705
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800706 if (probed_mod)
Keshavamurthy Anil Sdf019b12006-01-11 12:17:41 -0800707 module_put(probed_mod);
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800708
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 return ret;
710}
711
Masami Hiramatsu98616682008-04-28 02:14:28 -0700712/*
713 * Unregister a kprobe without a scheduler synchronization.
714 */
715static int __kprobes __unregister_kprobe_top(struct kprobe *p)
Keshavamurthy Anil Sdf019b12006-01-11 12:17:41 -0800716{
Keshavamurthy Anil Sf709b122006-01-09 20:52:44 -0800717 struct kprobe *old_p, *list_p;
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700718
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -0700719 old_p = get_kprobe(p->addr);
Masami Hiramatsu98616682008-04-28 02:14:28 -0700720 if (unlikely(!old_p))
721 return -EINVAL;
722
Keshavamurthy Anil Sf709b122006-01-09 20:52:44 -0800723 if (p != old_p) {
724 list_for_each_entry_rcu(list_p, &old_p->list, list)
725 if (list_p == p)
726 /* kprobe p is a valid probe */
727 goto valid_p;
Masami Hiramatsu98616682008-04-28 02:14:28 -0700728 return -EINVAL;
Keshavamurthy Anil Sf709b122006-01-09 20:52:44 -0800729 }
730valid_p:
Christoph Hellwig6f716ac2007-05-08 00:34:13 -0700731 if (old_p == p ||
732 (old_p->pre_handler == aggr_pre_handler &&
Masami Hiramatsu98616682008-04-28 02:14:28 -0700733 list_is_singular(&old_p->list))) {
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -0700734 /*
735 * Only probe on the hash list. Disarm only if kprobes are
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800736 * enabled and not gone - otherwise, the breakpoint would
737 * already have been removed. We save on flushing icache.
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -0700738 */
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800739 if (kprobe_enabled && !kprobe_gone(old_p))
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -0700740 arch_disarm_kprobe(p);
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -0800741 hlist_del_rcu(&old_p->hlist);
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -0800742 } else {
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800743 if (p->break_handler && !kprobe_gone(p))
Masami Hiramatsu98616682008-04-28 02:14:28 -0700744 old_p->break_handler = NULL;
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800745 if (p->post_handler && !kprobe_gone(p)) {
Masami Hiramatsu98616682008-04-28 02:14:28 -0700746 list_for_each_entry_rcu(list_p, &old_p->list, list) {
747 if ((list_p != p) && (list_p->post_handler))
748 goto noclean;
749 }
750 old_p->post_handler = NULL;
751 }
752noclean:
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -0800753 list_del_rcu(&p->list);
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -0800754 }
Masami Hiramatsu98616682008-04-28 02:14:28 -0700755 return 0;
756}
Mao, Bibob3e55c72005-12-12 00:37:00 -0800757
Masami Hiramatsu98616682008-04-28 02:14:28 -0700758static void __kprobes __unregister_kprobe_bottom(struct kprobe *p)
759{
Masami Hiramatsu98616682008-04-28 02:14:28 -0700760 struct kprobe *old_p;
Mao, Bibob3e55c72005-12-12 00:37:00 -0800761
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800762 if (list_empty(&p->list))
Ananth N Mavinakayanahalli0498b632006-01-09 20:52:46 -0800763 arch_remove_kprobe(p);
Masami Hiramatsue8386a02009-01-06 14:41:52 -0800764 else if (list_is_singular(&p->list)) {
765 /* "p" is the last child of an aggr_kprobe */
766 old_p = list_entry(p->list.next, struct kprobe, list);
767 list_del(&p->list);
768 arch_remove_kprobe(old_p);
769 kfree(old_p);
Anil S Keshavamurthy49a2a1b2006-01-09 20:52:43 -0800770 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771}
772
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -0800773int __kprobes register_kprobes(struct kprobe **kps, int num)
Masami Hiramatsu98616682008-04-28 02:14:28 -0700774{
775 int i, ret = 0;
776
777 if (num <= 0)
778 return -EINVAL;
779 for (i = 0; i < num; i++) {
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -0800780 ret = register_kprobe(kps[i]);
Masami Hiramatsu67dddaa2008-06-12 15:21:35 -0700781 if (ret < 0) {
782 if (i > 0)
783 unregister_kprobes(kps, i);
Masami Hiramatsu98616682008-04-28 02:14:28 -0700784 break;
785 }
786 }
787 return ret;
788}
789
Masami Hiramatsu98616682008-04-28 02:14:28 -0700790void __kprobes unregister_kprobe(struct kprobe *p)
791{
792 unregister_kprobes(&p, 1);
793}
794
Masami Hiramatsu98616682008-04-28 02:14:28 -0700795void __kprobes unregister_kprobes(struct kprobe **kps, int num)
796{
797 int i;
798
799 if (num <= 0)
800 return;
801 mutex_lock(&kprobe_mutex);
802 for (i = 0; i < num; i++)
803 if (__unregister_kprobe_top(kps[i]) < 0)
804 kps[i]->addr = NULL;
805 mutex_unlock(&kprobe_mutex);
806
807 synchronize_sched();
808 for (i = 0; i < num; i++)
809 if (kps[i]->addr)
810 __unregister_kprobe_bottom(kps[i]);
811}
812
Linus Torvalds1da177e2005-04-16 15:20:36 -0700813static struct notifier_block kprobe_exceptions_nb = {
814 .notifier_call = kprobe_exceptions_notify,
Anil S Keshavamurthy3d5631e2006-06-26 00:25:28 -0700815 .priority = 0x7fffffff /* we need to be notified first */
816};
817
Michael Ellerman3d7e3382007-07-19 01:48:11 -0700818unsigned long __weak arch_deref_entry_point(void *entry)
819{
820 return (unsigned long)entry;
821}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -0800823int __kprobes register_jprobes(struct jprobe **jps, int num)
Masami Hiramatsu26b31c12008-04-28 02:14:29 -0700824{
825 struct jprobe *jp;
826 int ret = 0, i;
827
828 if (num <= 0)
829 return -EINVAL;
830 for (i = 0; i < num; i++) {
831 unsigned long addr;
832 jp = jps[i];
833 addr = arch_deref_entry_point(jp->entry);
834
835 if (!kernel_text_address(addr))
836 ret = -EINVAL;
837 else {
838 /* Todo: Verify probepoint is a function entry point */
839 jp->kp.pre_handler = setjmp_pre_handler;
840 jp->kp.break_handler = longjmp_break_handler;
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -0800841 ret = register_kprobe(&jp->kp);
Masami Hiramatsu26b31c12008-04-28 02:14:29 -0700842 }
Masami Hiramatsu67dddaa2008-06-12 15:21:35 -0700843 if (ret < 0) {
844 if (i > 0)
845 unregister_jprobes(jps, i);
Masami Hiramatsu26b31c12008-04-28 02:14:29 -0700846 break;
847 }
848 }
849 return ret;
850}
851
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700852int __kprobes register_jprobe(struct jprobe *jp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700853{
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -0800854 return register_jprobes(&jp, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700855}
856
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -0700857void __kprobes unregister_jprobe(struct jprobe *jp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858{
Masami Hiramatsu26b31c12008-04-28 02:14:29 -0700859 unregister_jprobes(&jp, 1);
860}
861
Masami Hiramatsu26b31c12008-04-28 02:14:29 -0700862void __kprobes unregister_jprobes(struct jprobe **jps, int num)
863{
864 int i;
865
866 if (num <= 0)
867 return;
868 mutex_lock(&kprobe_mutex);
869 for (i = 0; i < num; i++)
870 if (__unregister_kprobe_top(&jps[i]->kp) < 0)
871 jps[i]->kp.addr = NULL;
872 mutex_unlock(&kprobe_mutex);
873
874 synchronize_sched();
875 for (i = 0; i < num; i++) {
876 if (jps[i]->kp.addr)
877 __unregister_kprobe_bottom(&jps[i]->kp);
878 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879}
880
Ananth N Mavinakayanahalli9edddaa2008-03-04 14:28:37 -0800881#ifdef CONFIG_KRETPROBES
Adrian Bunke65cefe2006-02-03 03:03:42 -0800882/*
883 * This kprobe pre_handler is registered with every kretprobe. When probe
884 * hits it will set up the return probe.
885 */
886static int __kprobes pre_handler_kretprobe(struct kprobe *p,
887 struct pt_regs *regs)
888{
889 struct kretprobe *rp = container_of(p, struct kretprobe, kp);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700890 unsigned long hash, flags = 0;
891 struct kretprobe_instance *ri;
Adrian Bunke65cefe2006-02-03 03:03:42 -0800892
893 /*TODO: consider to only swap the RA after the last pre_handler fired */
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700894 hash = hash_ptr(current, KPROBE_HASH_BITS);
895 spin_lock_irqsave(&rp->lock, flags);
Christoph Hellwig4c4308c2007-05-08 00:34:14 -0700896 if (!hlist_empty(&rp->free_instances)) {
Christoph Hellwig4c4308c2007-05-08 00:34:14 -0700897 ri = hlist_entry(rp->free_instances.first,
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700898 struct kretprobe_instance, hlist);
899 hlist_del(&ri->hlist);
900 spin_unlock_irqrestore(&rp->lock, flags);
901
Christoph Hellwig4c4308c2007-05-08 00:34:14 -0700902 ri->rp = rp;
903 ri->task = current;
Abhishek Sagarf47cd9b2008-02-06 01:38:22 -0800904
905 if (rp->entry_handler && rp->entry_handler(ri, regs)) {
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700906 spin_unlock_irqrestore(&rp->lock, flags);
Abhishek Sagarf47cd9b2008-02-06 01:38:22 -0800907 return 0;
908 }
909
Christoph Hellwig4c4308c2007-05-08 00:34:14 -0700910 arch_prepare_kretprobe(ri, regs);
911
912 /* XXX(hch): why is there no hlist_move_head? */
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700913 INIT_HLIST_NODE(&ri->hlist);
914 kretprobe_table_lock(hash, &flags);
915 hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]);
916 kretprobe_table_unlock(hash, &flags);
917 } else {
Christoph Hellwig4c4308c2007-05-08 00:34:14 -0700918 rp->nmissed++;
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700919 spin_unlock_irqrestore(&rp->lock, flags);
920 }
Adrian Bunke65cefe2006-02-03 03:03:42 -0800921 return 0;
922}
923
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -0800924int __kprobes register_kretprobe(struct kretprobe *rp)
Hien Nguyenb94cce92005-06-23 00:09:19 -0700925{
926 int ret = 0;
927 struct kretprobe_instance *inst;
928 int i;
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -0800929 void *addr;
Masami Hiramatsuf438d912007-10-16 01:27:49 -0700930
931 if (kretprobe_blacklist_size) {
Masami Hiramatsub2a5cd62008-03-04 14:29:44 -0800932 addr = kprobe_addr(&rp->kp);
933 if (!addr)
934 return -EINVAL;
Masami Hiramatsuf438d912007-10-16 01:27:49 -0700935
936 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
937 if (kretprobe_blacklist[i].addr == addr)
938 return -EINVAL;
939 }
940 }
Hien Nguyenb94cce92005-06-23 00:09:19 -0700941
942 rp->kp.pre_handler = pre_handler_kretprobe;
Ananth N Mavinakayanahalli7522a842006-04-20 02:43:11 -0700943 rp->kp.post_handler = NULL;
944 rp->kp.fault_handler = NULL;
945 rp->kp.break_handler = NULL;
Hien Nguyenb94cce92005-06-23 00:09:19 -0700946
947 /* Pre-allocate memory for max kretprobe instances */
948 if (rp->maxactive <= 0) {
949#ifdef CONFIG_PREEMPT
950 rp->maxactive = max(10, 2 * NR_CPUS);
951#else
952 rp->maxactive = NR_CPUS;
953#endif
954 }
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700955 spin_lock_init(&rp->lock);
Hien Nguyenb94cce92005-06-23 00:09:19 -0700956 INIT_HLIST_HEAD(&rp->free_instances);
957 for (i = 0; i < rp->maxactive; i++) {
Abhishek Sagarf47cd9b2008-02-06 01:38:22 -0800958 inst = kmalloc(sizeof(struct kretprobe_instance) +
959 rp->data_size, GFP_KERNEL);
Hien Nguyenb94cce92005-06-23 00:09:19 -0700960 if (inst == NULL) {
961 free_rp_inst(rp);
962 return -ENOMEM;
963 }
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700964 INIT_HLIST_NODE(&inst->hlist);
965 hlist_add_head(&inst->hlist, &rp->free_instances);
Hien Nguyenb94cce92005-06-23 00:09:19 -0700966 }
967
968 rp->nmissed = 0;
969 /* Establish function entry probe point */
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -0800970 ret = register_kprobe(&rp->kp);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -0700971 if (ret != 0)
Hien Nguyenb94cce92005-06-23 00:09:19 -0700972 free_rp_inst(rp);
973 return ret;
974}
975
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -0800976int __kprobes register_kretprobes(struct kretprobe **rps, int num)
Masami Hiramatsu4a296e02008-04-28 02:14:29 -0700977{
978 int ret = 0, i;
979
980 if (num <= 0)
981 return -EINVAL;
982 for (i = 0; i < num; i++) {
Masami Hiramatsu49ad2fd2009-01-06 14:41:53 -0800983 ret = register_kretprobe(rps[i]);
Masami Hiramatsu67dddaa2008-06-12 15:21:35 -0700984 if (ret < 0) {
985 if (i > 0)
986 unregister_kretprobes(rps, i);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -0700987 break;
988 }
989 }
990 return ret;
991}
992
Masami Hiramatsu4a296e02008-04-28 02:14:29 -0700993void __kprobes unregister_kretprobe(struct kretprobe *rp)
994{
995 unregister_kretprobes(&rp, 1);
996}
997
Masami Hiramatsu4a296e02008-04-28 02:14:29 -0700998void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
999{
1000 int i;
1001
1002 if (num <= 0)
1003 return;
1004 mutex_lock(&kprobe_mutex);
1005 for (i = 0; i < num; i++)
1006 if (__unregister_kprobe_top(&rps[i]->kp) < 0)
1007 rps[i]->kp.addr = NULL;
1008 mutex_unlock(&kprobe_mutex);
1009
1010 synchronize_sched();
1011 for (i = 0; i < num; i++) {
1012 if (rps[i]->kp.addr) {
1013 __unregister_kprobe_bottom(&rps[i]->kp);
1014 cleanup_rp_inst(rps[i]);
1015 }
1016 }
1017}
1018
Ananth N Mavinakayanahalli9edddaa2008-03-04 14:28:37 -08001019#else /* CONFIG_KRETPROBES */
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -07001020int __kprobes register_kretprobe(struct kretprobe *rp)
Hien Nguyenb94cce92005-06-23 00:09:19 -07001021{
1022 return -ENOSYS;
1023}
1024
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001025int __kprobes register_kretprobes(struct kretprobe **rps, int num)
1026{
1027 return -ENOSYS;
1028}
1029void __kprobes unregister_kretprobe(struct kretprobe *rp)
1030{
1031}
1032
1033void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
1034{
1035}
1036
Srinivasa Ds346fd592007-02-20 13:57:54 -08001037static int __kprobes pre_handler_kretprobe(struct kprobe *p,
1038 struct pt_regs *regs)
1039{
1040 return 0;
1041}
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001042
Ananth N Mavinakayanahalli9edddaa2008-03-04 14:28:37 -08001043#endif /* CONFIG_KRETPROBES */
Hien Nguyenb94cce92005-06-23 00:09:19 -07001044
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001045/* Set the kprobe gone and remove its instruction buffer. */
1046static void __kprobes kill_kprobe(struct kprobe *p)
1047{
1048 struct kprobe *kp;
1049 p->flags |= KPROBE_FLAG_GONE;
1050 if (p->pre_handler == aggr_pre_handler) {
1051 /*
1052 * If this is an aggr_kprobe, we have to list all the
1053 * chained probes and mark them GONE.
1054 */
1055 list_for_each_entry_rcu(kp, &p->list, list)
1056 kp->flags |= KPROBE_FLAG_GONE;
1057 p->post_handler = NULL;
1058 p->break_handler = NULL;
1059 }
1060 /*
1061 * Here, we can remove insn_slot safely, because no thread calls
1062 * the original probed function (which will be freed soon) any more.
1063 */
1064 arch_remove_kprobe(p);
1065}
1066
1067/* Module notifier call back, checking kprobes on the module */
1068static int __kprobes kprobes_module_callback(struct notifier_block *nb,
1069 unsigned long val, void *data)
1070{
1071 struct module *mod = data;
1072 struct hlist_head *head;
1073 struct hlist_node *node;
1074 struct kprobe *p;
1075 unsigned int i;
1076
1077 if (val != MODULE_STATE_GOING)
1078 return NOTIFY_DONE;
1079
1080 /*
1081 * module .text section will be freed. We need to
1082 * disable kprobes which have been inserted in the section.
1083 */
1084 mutex_lock(&kprobe_mutex);
1085 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1086 head = &kprobe_table[i];
1087 hlist_for_each_entry_rcu(p, node, head, hlist)
1088 if (within_module_core((unsigned long)p->addr, mod)) {
1089 /*
1090 * The vaddr this probe is installed will soon
1091 * be vfreed buy not synced to disk. Hence,
1092 * disarming the breakpoint isn't needed.
1093 */
1094 kill_kprobe(p);
1095 }
1096 }
1097 mutex_unlock(&kprobe_mutex);
1098 return NOTIFY_DONE;
1099}
1100
1101static struct notifier_block kprobe_module_nb = {
1102 .notifier_call = kprobes_module_callback,
1103 .priority = 0
1104};
1105
Linus Torvalds1da177e2005-04-16 15:20:36 -07001106static int __init init_kprobes(void)
1107{
1108 int i, err = 0;
Srinivasa Ds3d8d9962008-04-28 02:14:26 -07001109 unsigned long offset = 0, size = 0;
1110 char *modname, namebuf[128];
1111 const char *symbol_name;
1112 void *addr;
1113 struct kprobe_blackpoint *kb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001114
1115 /* FIXME allocate the probe table, currently defined statically */
1116 /* initialize all list heads */
Hien Nguyenb94cce92005-06-23 00:09:19 -07001117 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001118 INIT_HLIST_HEAD(&kprobe_table[i]);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001119 INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001120 spin_lock_init(&(kretprobe_table_locks[i].lock));
Hien Nguyenb94cce92005-06-23 00:09:19 -07001121 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001122
Srinivasa Ds3d8d9962008-04-28 02:14:26 -07001123 /*
1124 * Lookup and populate the kprobe_blacklist.
1125 *
1126 * Unlike the kretprobe blacklist, we'll need to determine
1127 * the range of addresses that belong to the said functions,
1128 * since a kprobe need not necessarily be at the beginning
1129 * of a function.
1130 */
1131 for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
1132 kprobe_lookup_name(kb->name, addr);
1133 if (!addr)
1134 continue;
1135
1136 kb->start_addr = (unsigned long)addr;
1137 symbol_name = kallsyms_lookup(kb->start_addr,
1138 &size, &offset, &modname, namebuf);
1139 if (!symbol_name)
1140 kb->range = 0;
1141 else
1142 kb->range = size;
1143 }
1144
Masami Hiramatsuf438d912007-10-16 01:27:49 -07001145 if (kretprobe_blacklist_size) {
1146 /* lookup the function address from its name */
1147 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
1148 kprobe_lookup_name(kretprobe_blacklist[i].name,
1149 kretprobe_blacklist[i].addr);
1150 if (!kretprobe_blacklist[i].addr)
1151 printk("kretprobe: lookup failed: %s\n",
1152 kretprobe_blacklist[i].name);
1153 }
1154 }
1155
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001156 /* By default, kprobes are enabled */
1157 kprobe_enabled = true;
1158
Rusty Lynch67729262005-07-05 18:54:50 -07001159 err = arch_init_kprobes();
Rusty Lynch802eae72005-06-27 15:17:08 -07001160 if (!err)
1161 err = register_die_notifier(&kprobe_exceptions_nb);
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001162 if (!err)
1163 err = register_module_notifier(&kprobe_module_nb);
1164
Srinivasa D Sef53d9c2008-07-25 01:46:04 -07001165 kprobes_initialized = (err == 0);
Rusty Lynch802eae72005-06-27 15:17:08 -07001166
Ananth N Mavinakayanahalli8c1c9352008-01-30 13:32:53 +01001167 if (!err)
1168 init_test_probes();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001169 return err;
1170}
1171
Srinivasa Ds346fd592007-02-20 13:57:54 -08001172#ifdef CONFIG_DEBUG_FS
1173static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p,
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001174 const char *sym, int offset,char *modname)
Srinivasa Ds346fd592007-02-20 13:57:54 -08001175{
1176 char *kprobe_type;
1177
1178 if (p->pre_handler == pre_handler_kretprobe)
1179 kprobe_type = "r";
1180 else if (p->pre_handler == setjmp_pre_handler)
1181 kprobe_type = "j";
1182 else
1183 kprobe_type = "k";
1184 if (sym)
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001185 seq_printf(pi, "%p %s %s+0x%x %s %s\n", p->addr, kprobe_type,
1186 sym, offset, (modname ? modname : " "),
1187 (kprobe_gone(p) ? "[GONE]" : ""));
Srinivasa Ds346fd592007-02-20 13:57:54 -08001188 else
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001189 seq_printf(pi, "%p %s %p %s\n", p->addr, kprobe_type, p->addr,
1190 (kprobe_gone(p) ? "[GONE]" : ""));
Srinivasa Ds346fd592007-02-20 13:57:54 -08001191}
1192
1193static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos)
1194{
1195 return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
1196}
1197
1198static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
1199{
1200 (*pos)++;
1201 if (*pos >= KPROBE_TABLE_SIZE)
1202 return NULL;
1203 return pos;
1204}
1205
1206static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v)
1207{
1208 /* Nothing to do */
1209}
1210
1211static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v)
1212{
1213 struct hlist_head *head;
1214 struct hlist_node *node;
1215 struct kprobe *p, *kp;
1216 const char *sym = NULL;
1217 unsigned int i = *(loff_t *) v;
Alexey Dobriyanffb45122007-05-08 00:28:41 -07001218 unsigned long offset = 0;
Srinivasa Ds346fd592007-02-20 13:57:54 -08001219 char *modname, namebuf[128];
1220
1221 head = &kprobe_table[i];
1222 preempt_disable();
1223 hlist_for_each_entry_rcu(p, node, head, hlist) {
Alexey Dobriyanffb45122007-05-08 00:28:41 -07001224 sym = kallsyms_lookup((unsigned long)p->addr, NULL,
Srinivasa Ds346fd592007-02-20 13:57:54 -08001225 &offset, &modname, namebuf);
1226 if (p->pre_handler == aggr_pre_handler) {
1227 list_for_each_entry_rcu(kp, &p->list, list)
1228 report_probe(pi, kp, sym, offset, modname);
1229 } else
1230 report_probe(pi, p, sym, offset, modname);
1231 }
1232 preempt_enable();
1233 return 0;
1234}
1235
1236static struct seq_operations kprobes_seq_ops = {
1237 .start = kprobe_seq_start,
1238 .next = kprobe_seq_next,
1239 .stop = kprobe_seq_stop,
1240 .show = show_kprobe_addr
1241};
1242
1243static int __kprobes kprobes_open(struct inode *inode, struct file *filp)
1244{
1245 return seq_open(filp, &kprobes_seq_ops);
1246}
1247
1248static struct file_operations debugfs_kprobes_operations = {
1249 .open = kprobes_open,
1250 .read = seq_read,
1251 .llseek = seq_lseek,
1252 .release = seq_release,
1253};
1254
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001255static void __kprobes enable_all_kprobes(void)
1256{
1257 struct hlist_head *head;
1258 struct hlist_node *node;
1259 struct kprobe *p;
1260 unsigned int i;
1261
1262 mutex_lock(&kprobe_mutex);
1263
1264 /* If kprobes are already enabled, just return */
1265 if (kprobe_enabled)
1266 goto already_enabled;
1267
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001268 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1269 head = &kprobe_table[i];
1270 hlist_for_each_entry_rcu(p, node, head, hlist)
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001271 if (!kprobe_gone(p))
1272 arch_arm_kprobe(p);
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001273 }
1274
1275 kprobe_enabled = true;
1276 printk(KERN_INFO "Kprobes globally enabled\n");
1277
1278already_enabled:
1279 mutex_unlock(&kprobe_mutex);
1280 return;
1281}
1282
1283static void __kprobes disable_all_kprobes(void)
1284{
1285 struct hlist_head *head;
1286 struct hlist_node *node;
1287 struct kprobe *p;
1288 unsigned int i;
1289
1290 mutex_lock(&kprobe_mutex);
1291
1292 /* If kprobes are already disabled, just return */
1293 if (!kprobe_enabled)
1294 goto already_disabled;
1295
1296 kprobe_enabled = false;
1297 printk(KERN_INFO "Kprobes globally disabled\n");
1298 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1299 head = &kprobe_table[i];
1300 hlist_for_each_entry_rcu(p, node, head, hlist) {
Masami Hiramatsue8386a02009-01-06 14:41:52 -08001301 if (!arch_trampoline_kprobe(p) && !kprobe_gone(p))
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001302 arch_disarm_kprobe(p);
1303 }
1304 }
1305
1306 mutex_unlock(&kprobe_mutex);
1307 /* Allow all currently running kprobes to complete */
1308 synchronize_sched();
Christoph Hellwig74a0b572007-10-16 01:24:07 -07001309 return;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001310
1311already_disabled:
1312 mutex_unlock(&kprobe_mutex);
1313 return;
1314}
1315
1316/*
1317 * XXX: The debugfs bool file interface doesn't allow for callbacks
1318 * when the bool state is switched. We can reuse that facility when
1319 * available
1320 */
1321static ssize_t read_enabled_file_bool(struct file *file,
1322 char __user *user_buf, size_t count, loff_t *ppos)
1323{
1324 char buf[3];
1325
1326 if (kprobe_enabled)
1327 buf[0] = '1';
1328 else
1329 buf[0] = '0';
1330 buf[1] = '\n';
1331 buf[2] = 0x00;
1332 return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
1333}
1334
1335static ssize_t write_enabled_file_bool(struct file *file,
1336 const char __user *user_buf, size_t count, loff_t *ppos)
1337{
1338 char buf[32];
1339 int buf_size;
1340
1341 buf_size = min(count, (sizeof(buf)-1));
1342 if (copy_from_user(buf, user_buf, buf_size))
1343 return -EFAULT;
1344
1345 switch (buf[0]) {
1346 case 'y':
1347 case 'Y':
1348 case '1':
1349 enable_all_kprobes();
1350 break;
1351 case 'n':
1352 case 'N':
1353 case '0':
1354 disable_all_kprobes();
1355 break;
1356 }
1357
1358 return count;
1359}
1360
1361static struct file_operations fops_kp = {
1362 .read = read_enabled_file_bool,
1363 .write = write_enabled_file_bool,
1364};
1365
Srinivasa Ds346fd592007-02-20 13:57:54 -08001366static int __kprobes debugfs_kprobe_init(void)
1367{
1368 struct dentry *dir, *file;
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001369 unsigned int value = 1;
Srinivasa Ds346fd592007-02-20 13:57:54 -08001370
1371 dir = debugfs_create_dir("kprobes", NULL);
1372 if (!dir)
1373 return -ENOMEM;
1374
Randy Dunlape3869792007-05-08 00:27:01 -07001375 file = debugfs_create_file("list", 0444, dir, NULL,
Srinivasa Ds346fd592007-02-20 13:57:54 -08001376 &debugfs_kprobes_operations);
1377 if (!file) {
1378 debugfs_remove(dir);
1379 return -ENOMEM;
1380 }
1381
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001382 file = debugfs_create_file("enabled", 0600, dir,
1383 &value, &fops_kp);
1384 if (!file) {
1385 debugfs_remove(dir);
1386 return -ENOMEM;
1387 }
1388
Srinivasa Ds346fd592007-02-20 13:57:54 -08001389 return 0;
1390}
1391
1392late_initcall(debugfs_kprobe_init);
1393#endif /* CONFIG_DEBUG_FS */
1394
1395module_init(init_kprobes);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001396
1397EXPORT_SYMBOL_GPL(register_kprobe);
1398EXPORT_SYMBOL_GPL(unregister_kprobe);
Masami Hiramatsu98616682008-04-28 02:14:28 -07001399EXPORT_SYMBOL_GPL(register_kprobes);
1400EXPORT_SYMBOL_GPL(unregister_kprobes);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001401EXPORT_SYMBOL_GPL(register_jprobe);
1402EXPORT_SYMBOL_GPL(unregister_jprobe);
Masami Hiramatsu26b31c12008-04-28 02:14:29 -07001403EXPORT_SYMBOL_GPL(register_jprobes);
1404EXPORT_SYMBOL_GPL(unregister_jprobes);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001405EXPORT_SYMBOL_GPL(jprobe_return);
Hien Nguyenb94cce92005-06-23 00:09:19 -07001406EXPORT_SYMBOL_GPL(register_kretprobe);
1407EXPORT_SYMBOL_GPL(unregister_kretprobe);
Masami Hiramatsu4a296e02008-04-28 02:14:29 -07001408EXPORT_SYMBOL_GPL(register_kretprobes);
1409EXPORT_SYMBOL_GPL(unregister_kretprobes);