Commit | Line | Data |
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1da177e4 LT |
1 | /* |
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. | |
b94cce92 HN |
30 | * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston |
31 | * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi | |
32 | * <prasanna@in.ibm.com> added function-return probes. | |
1da177e4 LT |
33 | */ |
34 | #include <linux/kprobes.h> | |
1da177e4 LT |
35 | #include <linux/hash.h> |
36 | #include <linux/init.h> | |
4e57b681 | 37 | #include <linux/slab.h> |
e3869792 | 38 | #include <linux/stddef.h> |
1da177e4 | 39 | #include <linux/module.h> |
9ec4b1f3 | 40 | #include <linux/moduleloader.h> |
3a872d89 | 41 | #include <linux/kallsyms.h> |
b4c6c34a | 42 | #include <linux/freezer.h> |
346fd59b SD |
43 | #include <linux/seq_file.h> |
44 | #include <linux/debugfs.h> | |
1eeb66a1 | 45 | #include <linux/kdebug.h> |
4460fdad | 46 | #include <linux/memory.h> |
4554dbcb | 47 | #include <linux/ftrace.h> |
bf8f6e5b | 48 | |
d0aaff97 | 49 | #include <asm-generic/sections.h> |
1da177e4 LT |
50 | #include <asm/cacheflush.h> |
51 | #include <asm/errno.h> | |
bf8f6e5b | 52 | #include <asm/uaccess.h> |
1da177e4 LT |
53 | |
54 | #define KPROBE_HASH_BITS 6 | |
55 | #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS) | |
56 | ||
3a872d89 AM |
57 | |
58 | /* | |
59 | * Some oddball architectures like 64bit powerpc have function descriptors | |
60 | * so this must be overridable. | |
61 | */ | |
62 | #ifndef kprobe_lookup_name | |
63 | #define kprobe_lookup_name(name, addr) \ | |
64 | addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name))) | |
65 | #endif | |
66 | ||
ef53d9c5 | 67 | static int kprobes_initialized; |
1da177e4 | 68 | static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; |
b94cce92 | 69 | static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; |
1da177e4 | 70 | |
bf8f6e5b | 71 | /* NOTE: change this value only with kprobe_mutex held */ |
e579abeb | 72 | static bool kprobes_all_disarmed; |
bf8f6e5b | 73 | |
12941560 | 74 | static DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */ |
e6584523 | 75 | static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; |
ef53d9c5 | 76 | static struct { |
7e036d04 | 77 | spinlock_t lock ____cacheline_aligned_in_smp; |
ef53d9c5 S |
78 | } kretprobe_table_locks[KPROBE_TABLE_SIZE]; |
79 | ||
80 | static spinlock_t *kretprobe_table_lock_ptr(unsigned long hash) | |
81 | { | |
82 | return &(kretprobe_table_locks[hash].lock); | |
83 | } | |
1da177e4 | 84 | |
3d8d996e SD |
85 | /* |
86 | * Normally, functions that we'd want to prohibit kprobes in, are marked | |
87 | * __kprobes. But, there are cases where such functions already belong to | |
88 | * a different section (__sched for preempt_schedule) | |
89 | * | |
90 | * For such cases, we now have a blacklist | |
91 | */ | |
544304b2 | 92 | static struct kprobe_blackpoint kprobe_blacklist[] = { |
3d8d996e | 93 | {"preempt_schedule",}, |
65e234ec | 94 | {"native_get_debugreg",}, |
a00e817f MH |
95 | {"irq_entries_start",}, |
96 | {"common_interrupt",}, | |
5ecaafdb | 97 | {"mcount",}, /* mcount can be called from everywhere */ |
3d8d996e SD |
98 | {NULL} /* Terminator */ |
99 | }; | |
100 | ||
2d14e39d | 101 | #ifdef __ARCH_WANT_KPROBES_INSN_SLOT |
9ec4b1f3 AM |
102 | /* |
103 | * kprobe->ainsn.insn points to the copy of the instruction to be | |
104 | * single-stepped. x86_64, POWER4 and above have no-exec support and | |
105 | * stepping on the instruction on a vmalloced/kmalloced/data page | |
106 | * is a recipe for disaster | |
107 | */ | |
108 | #define INSNS_PER_PAGE (PAGE_SIZE/(MAX_INSN_SIZE * sizeof(kprobe_opcode_t))) | |
109 | ||
110 | struct kprobe_insn_page { | |
c5cb5a2d | 111 | struct list_head list; |
9ec4b1f3 AM |
112 | kprobe_opcode_t *insns; /* Page of instruction slots */ |
113 | char slot_used[INSNS_PER_PAGE]; | |
114 | int nused; | |
b4c6c34a | 115 | int ngarbage; |
9ec4b1f3 AM |
116 | }; |
117 | ||
ab40c5c6 MH |
118 | enum kprobe_slot_state { |
119 | SLOT_CLEAN = 0, | |
120 | SLOT_DIRTY = 1, | |
121 | SLOT_USED = 2, | |
122 | }; | |
123 | ||
12941560 | 124 | static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_pages */ |
c5cb5a2d | 125 | static LIST_HEAD(kprobe_insn_pages); |
b4c6c34a MH |
126 | static int kprobe_garbage_slots; |
127 | static int collect_garbage_slots(void); | |
128 | ||
9ec4b1f3 | 129 | /** |
12941560 | 130 | * __get_insn_slot() - Find a slot on an executable page for an instruction. |
9ec4b1f3 AM |
131 | * We allocate an executable page if there's no room on existing ones. |
132 | */ | |
12941560 | 133 | static kprobe_opcode_t __kprobes *__get_insn_slot(void) |
9ec4b1f3 AM |
134 | { |
135 | struct kprobe_insn_page *kip; | |
9ec4b1f3 | 136 | |
6f716acd | 137 | retry: |
c5cb5a2d | 138 | list_for_each_entry(kip, &kprobe_insn_pages, list) { |
9ec4b1f3 AM |
139 | if (kip->nused < INSNS_PER_PAGE) { |
140 | int i; | |
141 | for (i = 0; i < INSNS_PER_PAGE; i++) { | |
ab40c5c6 MH |
142 | if (kip->slot_used[i] == SLOT_CLEAN) { |
143 | kip->slot_used[i] = SLOT_USED; | |
9ec4b1f3 AM |
144 | kip->nused++; |
145 | return kip->insns + (i * MAX_INSN_SIZE); | |
146 | } | |
147 | } | |
148 | /* Surprise! No unused slots. Fix kip->nused. */ | |
149 | kip->nused = INSNS_PER_PAGE; | |
150 | } | |
151 | } | |
152 | ||
b4c6c34a MH |
153 | /* If there are any garbage slots, collect it and try again. */ |
154 | if (kprobe_garbage_slots && collect_garbage_slots() == 0) { | |
155 | goto retry; | |
156 | } | |
157 | /* All out of space. Need to allocate a new page. Use slot 0. */ | |
9ec4b1f3 | 158 | kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL); |
6f716acd | 159 | if (!kip) |
9ec4b1f3 | 160 | return NULL; |
9ec4b1f3 AM |
161 | |
162 | /* | |
163 | * Use module_alloc so this page is within +/- 2GB of where the | |
164 | * kernel image and loaded module images reside. This is required | |
165 | * so x86_64 can correctly handle the %rip-relative fixups. | |
166 | */ | |
167 | kip->insns = module_alloc(PAGE_SIZE); | |
168 | if (!kip->insns) { | |
169 | kfree(kip); | |
170 | return NULL; | |
171 | } | |
c5cb5a2d MH |
172 | INIT_LIST_HEAD(&kip->list); |
173 | list_add(&kip->list, &kprobe_insn_pages); | |
ab40c5c6 MH |
174 | memset(kip->slot_used, SLOT_CLEAN, INSNS_PER_PAGE); |
175 | kip->slot_used[0] = SLOT_USED; | |
9ec4b1f3 | 176 | kip->nused = 1; |
b4c6c34a | 177 | kip->ngarbage = 0; |
9ec4b1f3 AM |
178 | return kip->insns; |
179 | } | |
180 | ||
12941560 MH |
181 | kprobe_opcode_t __kprobes *get_insn_slot(void) |
182 | { | |
183 | kprobe_opcode_t *ret; | |
184 | mutex_lock(&kprobe_insn_mutex); | |
185 | ret = __get_insn_slot(); | |
186 | mutex_unlock(&kprobe_insn_mutex); | |
187 | return ret; | |
188 | } | |
189 | ||
b4c6c34a MH |
190 | /* Return 1 if all garbages are collected, otherwise 0. */ |
191 | static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx) | |
192 | { | |
ab40c5c6 | 193 | kip->slot_used[idx] = SLOT_CLEAN; |
b4c6c34a MH |
194 | kip->nused--; |
195 | if (kip->nused == 0) { | |
196 | /* | |
197 | * Page is no longer in use. Free it unless | |
198 | * it's the last one. We keep the last one | |
199 | * so as not to have to set it up again the | |
200 | * next time somebody inserts a probe. | |
201 | */ | |
c5cb5a2d MH |
202 | if (!list_is_singular(&kprobe_insn_pages)) { |
203 | list_del(&kip->list); | |
b4c6c34a MH |
204 | module_free(NULL, kip->insns); |
205 | kfree(kip); | |
206 | } | |
207 | return 1; | |
208 | } | |
209 | return 0; | |
210 | } | |
211 | ||
212 | static int __kprobes collect_garbage_slots(void) | |
213 | { | |
c5cb5a2d | 214 | struct kprobe_insn_page *kip, *next; |
b4c6c34a | 215 | |
615d0ebb MH |
216 | /* Ensure no-one is interrupted on the garbages */ |
217 | synchronize_sched(); | |
b4c6c34a | 218 | |
c5cb5a2d | 219 | list_for_each_entry_safe(kip, next, &kprobe_insn_pages, list) { |
b4c6c34a | 220 | int i; |
b4c6c34a MH |
221 | if (kip->ngarbage == 0) |
222 | continue; | |
223 | kip->ngarbage = 0; /* we will collect all garbages */ | |
224 | for (i = 0; i < INSNS_PER_PAGE; i++) { | |
ab40c5c6 | 225 | if (kip->slot_used[i] == SLOT_DIRTY && |
b4c6c34a MH |
226 | collect_one_slot(kip, i)) |
227 | break; | |
228 | } | |
229 | } | |
230 | kprobe_garbage_slots = 0; | |
231 | return 0; | |
232 | } | |
233 | ||
234 | void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty) | |
9ec4b1f3 AM |
235 | { |
236 | struct kprobe_insn_page *kip; | |
9ec4b1f3 | 237 | |
12941560 | 238 | mutex_lock(&kprobe_insn_mutex); |
c5cb5a2d | 239 | list_for_each_entry(kip, &kprobe_insn_pages, list) { |
9ec4b1f3 AM |
240 | if (kip->insns <= slot && |
241 | slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) { | |
242 | int i = (slot - kip->insns) / MAX_INSN_SIZE; | |
b4c6c34a | 243 | if (dirty) { |
ab40c5c6 | 244 | kip->slot_used[i] = SLOT_DIRTY; |
b4c6c34a | 245 | kip->ngarbage++; |
c5cb5a2d | 246 | } else |
b4c6c34a | 247 | collect_one_slot(kip, i); |
b4c6c34a | 248 | break; |
9ec4b1f3 AM |
249 | } |
250 | } | |
6f716acd CH |
251 | |
252 | if (dirty && ++kprobe_garbage_slots > INSNS_PER_PAGE) | |
b4c6c34a | 253 | collect_garbage_slots(); |
12941560 MH |
254 | |
255 | mutex_unlock(&kprobe_insn_mutex); | |
9ec4b1f3 | 256 | } |
2d14e39d | 257 | #endif |
9ec4b1f3 | 258 | |
e6584523 AM |
259 | /* We have preemption disabled.. so it is safe to use __ versions */ |
260 | static inline void set_kprobe_instance(struct kprobe *kp) | |
261 | { | |
262 | __get_cpu_var(kprobe_instance) = kp; | |
263 | } | |
264 | ||
265 | static inline void reset_kprobe_instance(void) | |
266 | { | |
267 | __get_cpu_var(kprobe_instance) = NULL; | |
268 | } | |
269 | ||
3516a460 AM |
270 | /* |
271 | * This routine is called either: | |
49a2a1b8 | 272 | * - under the kprobe_mutex - during kprobe_[un]register() |
3516a460 | 273 | * OR |
d217d545 | 274 | * - with preemption disabled - from arch/xxx/kernel/kprobes.c |
3516a460 | 275 | */ |
d0aaff97 | 276 | struct kprobe __kprobes *get_kprobe(void *addr) |
1da177e4 LT |
277 | { |
278 | struct hlist_head *head; | |
279 | struct hlist_node *node; | |
3516a460 | 280 | struct kprobe *p; |
1da177e4 LT |
281 | |
282 | head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; | |
3516a460 | 283 | hlist_for_each_entry_rcu(p, node, head, hlist) { |
1da177e4 LT |
284 | if (p->addr == addr) |
285 | return p; | |
286 | } | |
287 | return NULL; | |
288 | } | |
289 | ||
201517a7 MH |
290 | /* Arm a kprobe with text_mutex */ |
291 | static void __kprobes arm_kprobe(struct kprobe *kp) | |
292 | { | |
293 | mutex_lock(&text_mutex); | |
294 | arch_arm_kprobe(kp); | |
295 | mutex_unlock(&text_mutex); | |
296 | } | |
297 | ||
298 | /* Disarm a kprobe with text_mutex */ | |
299 | static void __kprobes disarm_kprobe(struct kprobe *kp) | |
300 | { | |
301 | mutex_lock(&text_mutex); | |
302 | arch_disarm_kprobe(kp); | |
303 | mutex_unlock(&text_mutex); | |
304 | } | |
305 | ||
64f562c6 AM |
306 | /* |
307 | * Aggregate handlers for multiple kprobes support - these handlers | |
308 | * take care of invoking the individual kprobe handlers on p->list | |
309 | */ | |
d0aaff97 | 310 | static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
64f562c6 AM |
311 | { |
312 | struct kprobe *kp; | |
313 | ||
3516a460 | 314 | list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d | 315 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
e6584523 | 316 | set_kprobe_instance(kp); |
8b0914ea PP |
317 | if (kp->pre_handler(kp, regs)) |
318 | return 1; | |
64f562c6 | 319 | } |
e6584523 | 320 | reset_kprobe_instance(); |
64f562c6 AM |
321 | } |
322 | return 0; | |
323 | } | |
324 | ||
d0aaff97 PP |
325 | static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
326 | unsigned long flags) | |
64f562c6 AM |
327 | { |
328 | struct kprobe *kp; | |
329 | ||
3516a460 | 330 | list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d | 331 | if (kp->post_handler && likely(!kprobe_disabled(kp))) { |
e6584523 | 332 | set_kprobe_instance(kp); |
64f562c6 | 333 | kp->post_handler(kp, regs, flags); |
e6584523 | 334 | reset_kprobe_instance(); |
64f562c6 AM |
335 | } |
336 | } | |
64f562c6 AM |
337 | } |
338 | ||
d0aaff97 PP |
339 | static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, |
340 | int trapnr) | |
64f562c6 | 341 | { |
e6584523 AM |
342 | struct kprobe *cur = __get_cpu_var(kprobe_instance); |
343 | ||
64f562c6 AM |
344 | /* |
345 | * if we faulted "during" the execution of a user specified | |
346 | * probe handler, invoke just that probe's fault handler | |
347 | */ | |
e6584523 AM |
348 | if (cur && cur->fault_handler) { |
349 | if (cur->fault_handler(cur, regs, trapnr)) | |
64f562c6 AM |
350 | return 1; |
351 | } | |
352 | return 0; | |
353 | } | |
354 | ||
d0aaff97 | 355 | static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs) |
8b0914ea | 356 | { |
e6584523 AM |
357 | struct kprobe *cur = __get_cpu_var(kprobe_instance); |
358 | int ret = 0; | |
359 | ||
360 | if (cur && cur->break_handler) { | |
361 | if (cur->break_handler(cur, regs)) | |
362 | ret = 1; | |
8b0914ea | 363 | } |
e6584523 AM |
364 | reset_kprobe_instance(); |
365 | return ret; | |
8b0914ea PP |
366 | } |
367 | ||
bf8d5c52 KA |
368 | /* Walks the list and increments nmissed count for multiprobe case */ |
369 | void __kprobes kprobes_inc_nmissed_count(struct kprobe *p) | |
370 | { | |
371 | struct kprobe *kp; | |
372 | if (p->pre_handler != aggr_pre_handler) { | |
373 | p->nmissed++; | |
374 | } else { | |
375 | list_for_each_entry_rcu(kp, &p->list, list) | |
376 | kp->nmissed++; | |
377 | } | |
378 | return; | |
379 | } | |
380 | ||
99219a3f | 381 | void __kprobes recycle_rp_inst(struct kretprobe_instance *ri, |
382 | struct hlist_head *head) | |
b94cce92 | 383 | { |
ef53d9c5 S |
384 | struct kretprobe *rp = ri->rp; |
385 | ||
b94cce92 HN |
386 | /* remove rp inst off the rprobe_inst_table */ |
387 | hlist_del(&ri->hlist); | |
ef53d9c5 S |
388 | INIT_HLIST_NODE(&ri->hlist); |
389 | if (likely(rp)) { | |
390 | spin_lock(&rp->lock); | |
391 | hlist_add_head(&ri->hlist, &rp->free_instances); | |
392 | spin_unlock(&rp->lock); | |
b94cce92 HN |
393 | } else |
394 | /* Unregistering */ | |
99219a3f | 395 | hlist_add_head(&ri->hlist, head); |
b94cce92 HN |
396 | } |
397 | ||
017c39bd | 398 | void __kprobes kretprobe_hash_lock(struct task_struct *tsk, |
ef53d9c5 S |
399 | struct hlist_head **head, unsigned long *flags) |
400 | { | |
401 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); | |
402 | spinlock_t *hlist_lock; | |
403 | ||
404 | *head = &kretprobe_inst_table[hash]; | |
405 | hlist_lock = kretprobe_table_lock_ptr(hash); | |
406 | spin_lock_irqsave(hlist_lock, *flags); | |
407 | } | |
408 | ||
017c39bd MH |
409 | static void __kprobes kretprobe_table_lock(unsigned long hash, |
410 | unsigned long *flags) | |
b94cce92 | 411 | { |
ef53d9c5 S |
412 | spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
413 | spin_lock_irqsave(hlist_lock, *flags); | |
414 | } | |
415 | ||
017c39bd MH |
416 | void __kprobes kretprobe_hash_unlock(struct task_struct *tsk, |
417 | unsigned long *flags) | |
ef53d9c5 S |
418 | { |
419 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); | |
420 | spinlock_t *hlist_lock; | |
421 | ||
422 | hlist_lock = kretprobe_table_lock_ptr(hash); | |
423 | spin_unlock_irqrestore(hlist_lock, *flags); | |
424 | } | |
425 | ||
017c39bd | 426 | void __kprobes kretprobe_table_unlock(unsigned long hash, unsigned long *flags) |
ef53d9c5 S |
427 | { |
428 | spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); | |
429 | spin_unlock_irqrestore(hlist_lock, *flags); | |
b94cce92 HN |
430 | } |
431 | ||
b94cce92 | 432 | /* |
c6fd91f0 | 433 | * This function is called from finish_task_switch when task tk becomes dead, |
434 | * so that we can recycle any function-return probe instances associated | |
435 | * with this task. These left over instances represent probed functions | |
436 | * that have been called but will never return. | |
b94cce92 | 437 | */ |
d0aaff97 | 438 | void __kprobes kprobe_flush_task(struct task_struct *tk) |
b94cce92 | 439 | { |
62c27be0 | 440 | struct kretprobe_instance *ri; |
99219a3f | 441 | struct hlist_head *head, empty_rp; |
802eae7c | 442 | struct hlist_node *node, *tmp; |
ef53d9c5 | 443 | unsigned long hash, flags = 0; |
802eae7c | 444 | |
ef53d9c5 S |
445 | if (unlikely(!kprobes_initialized)) |
446 | /* Early boot. kretprobe_table_locks not yet initialized. */ | |
447 | return; | |
448 | ||
449 | hash = hash_ptr(tk, KPROBE_HASH_BITS); | |
450 | head = &kretprobe_inst_table[hash]; | |
451 | kretprobe_table_lock(hash, &flags); | |
62c27be0 | 452 | hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { |
453 | if (ri->task == tk) | |
99219a3f | 454 | recycle_rp_inst(ri, &empty_rp); |
62c27be0 | 455 | } |
ef53d9c5 S |
456 | kretprobe_table_unlock(hash, &flags); |
457 | INIT_HLIST_HEAD(&empty_rp); | |
99219a3f | 458 | hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { |
459 | hlist_del(&ri->hlist); | |
460 | kfree(ri); | |
461 | } | |
b94cce92 HN |
462 | } |
463 | ||
b94cce92 HN |
464 | static inline void free_rp_inst(struct kretprobe *rp) |
465 | { | |
466 | struct kretprobe_instance *ri; | |
4c4308cb CH |
467 | struct hlist_node *pos, *next; |
468 | ||
ef53d9c5 S |
469 | hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) { |
470 | hlist_del(&ri->hlist); | |
b94cce92 HN |
471 | kfree(ri); |
472 | } | |
473 | } | |
474 | ||
4a296e07 MH |
475 | static void __kprobes cleanup_rp_inst(struct kretprobe *rp) |
476 | { | |
ef53d9c5 | 477 | unsigned long flags, hash; |
4a296e07 MH |
478 | struct kretprobe_instance *ri; |
479 | struct hlist_node *pos, *next; | |
ef53d9c5 S |
480 | struct hlist_head *head; |
481 | ||
4a296e07 | 482 | /* No race here */ |
ef53d9c5 S |
483 | for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) { |
484 | kretprobe_table_lock(hash, &flags); | |
485 | head = &kretprobe_inst_table[hash]; | |
486 | hlist_for_each_entry_safe(ri, pos, next, head, hlist) { | |
487 | if (ri->rp == rp) | |
488 | ri->rp = NULL; | |
489 | } | |
490 | kretprobe_table_unlock(hash, &flags); | |
4a296e07 | 491 | } |
4a296e07 MH |
492 | free_rp_inst(rp); |
493 | } | |
494 | ||
8b0914ea PP |
495 | /* |
496 | * Keep all fields in the kprobe consistent | |
497 | */ | |
498 | static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p) | |
499 | { | |
500 | memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t)); | |
501 | memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn)); | |
502 | } | |
503 | ||
504 | /* | |
b918e5e6 | 505 | * Add the new probe to ap->list. Fail if this is the |
8b0914ea PP |
506 | * second jprobe at the address - two jprobes can't coexist |
507 | */ | |
b918e5e6 | 508 | static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p) |
8b0914ea | 509 | { |
de5bd88d | 510 | BUG_ON(kprobe_gone(ap) || kprobe_gone(p)); |
8b0914ea | 511 | if (p->break_handler) { |
b918e5e6 | 512 | if (ap->break_handler) |
36721656 | 513 | return -EEXIST; |
b918e5e6 MH |
514 | list_add_tail_rcu(&p->list, &ap->list); |
515 | ap->break_handler = aggr_break_handler; | |
8b0914ea | 516 | } else |
b918e5e6 MH |
517 | list_add_rcu(&p->list, &ap->list); |
518 | if (p->post_handler && !ap->post_handler) | |
519 | ap->post_handler = aggr_post_handler; | |
de5bd88d MH |
520 | |
521 | if (kprobe_disabled(ap) && !kprobe_disabled(p)) { | |
522 | ap->flags &= ~KPROBE_FLAG_DISABLED; | |
523 | if (!kprobes_all_disarmed) | |
524 | /* Arm the breakpoint again. */ | |
201517a7 | 525 | arm_kprobe(ap); |
de5bd88d | 526 | } |
8b0914ea PP |
527 | return 0; |
528 | } | |
529 | ||
64f562c6 AM |
530 | /* |
531 | * Fill in the required fields of the "manager kprobe". Replace the | |
532 | * earlier kprobe in the hlist with the manager kprobe | |
533 | */ | |
534 | static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p) | |
535 | { | |
8b0914ea | 536 | copy_kprobe(p, ap); |
a9ad965e | 537 | flush_insn_slot(ap); |
64f562c6 | 538 | ap->addr = p->addr; |
b918e5e6 | 539 | ap->flags = p->flags; |
64f562c6 | 540 | ap->pre_handler = aggr_pre_handler; |
64f562c6 | 541 | ap->fault_handler = aggr_fault_handler; |
e8386a0c MH |
542 | /* We don't care the kprobe which has gone. */ |
543 | if (p->post_handler && !kprobe_gone(p)) | |
36721656 | 544 | ap->post_handler = aggr_post_handler; |
e8386a0c | 545 | if (p->break_handler && !kprobe_gone(p)) |
36721656 | 546 | ap->break_handler = aggr_break_handler; |
64f562c6 AM |
547 | |
548 | INIT_LIST_HEAD(&ap->list); | |
3516a460 | 549 | list_add_rcu(&p->list, &ap->list); |
64f562c6 | 550 | |
adad0f33 | 551 | hlist_replace_rcu(&p->hlist, &ap->hlist); |
64f562c6 AM |
552 | } |
553 | ||
554 | /* | |
555 | * This is the second or subsequent kprobe at the address - handle | |
556 | * the intricacies | |
64f562c6 | 557 | */ |
d0aaff97 PP |
558 | static int __kprobes register_aggr_kprobe(struct kprobe *old_p, |
559 | struct kprobe *p) | |
64f562c6 AM |
560 | { |
561 | int ret = 0; | |
b918e5e6 | 562 | struct kprobe *ap = old_p; |
64f562c6 | 563 | |
b918e5e6 MH |
564 | if (old_p->pre_handler != aggr_pre_handler) { |
565 | /* If old_p is not an aggr_probe, create new aggr_kprobe. */ | |
566 | ap = kzalloc(sizeof(struct kprobe), GFP_KERNEL); | |
567 | if (!ap) | |
568 | return -ENOMEM; | |
569 | add_aggr_kprobe(ap, old_p); | |
570 | } | |
571 | ||
572 | if (kprobe_gone(ap)) { | |
e8386a0c MH |
573 | /* |
574 | * Attempting to insert new probe at the same location that | |
575 | * had a probe in the module vaddr area which already | |
576 | * freed. So, the instruction slot has already been | |
577 | * released. We need a new slot for the new probe. | |
578 | */ | |
b918e5e6 | 579 | ret = arch_prepare_kprobe(ap); |
e8386a0c | 580 | if (ret) |
b918e5e6 MH |
581 | /* |
582 | * Even if fail to allocate new slot, don't need to | |
583 | * free aggr_probe. It will be used next time, or | |
584 | * freed by unregister_kprobe. | |
585 | */ | |
e8386a0c | 586 | return ret; |
de5bd88d | 587 | |
e8386a0c | 588 | /* |
de5bd88d MH |
589 | * Clear gone flag to prevent allocating new slot again, and |
590 | * set disabled flag because it is not armed yet. | |
e8386a0c | 591 | */ |
de5bd88d MH |
592 | ap->flags = (ap->flags & ~KPROBE_FLAG_GONE) |
593 | | KPROBE_FLAG_DISABLED; | |
e8386a0c | 594 | } |
b918e5e6 MH |
595 | |
596 | copy_kprobe(ap, p); | |
597 | return add_new_kprobe(ap, p); | |
64f562c6 AM |
598 | } |
599 | ||
de5bd88d MH |
600 | /* Try to disable aggr_kprobe, and return 1 if succeeded.*/ |
601 | static int __kprobes try_to_disable_aggr_kprobe(struct kprobe *p) | |
602 | { | |
603 | struct kprobe *kp; | |
604 | ||
605 | list_for_each_entry_rcu(kp, &p->list, list) { | |
606 | if (!kprobe_disabled(kp)) | |
607 | /* | |
608 | * There is an active probe on the list. | |
609 | * We can't disable aggr_kprobe. | |
610 | */ | |
611 | return 0; | |
612 | } | |
613 | p->flags |= KPROBE_FLAG_DISABLED; | |
614 | return 1; | |
615 | } | |
616 | ||
d0aaff97 PP |
617 | static int __kprobes in_kprobes_functions(unsigned long addr) |
618 | { | |
3d8d996e SD |
619 | struct kprobe_blackpoint *kb; |
620 | ||
6f716acd CH |
621 | if (addr >= (unsigned long)__kprobes_text_start && |
622 | addr < (unsigned long)__kprobes_text_end) | |
d0aaff97 | 623 | return -EINVAL; |
3d8d996e SD |
624 | /* |
625 | * If there exists a kprobe_blacklist, verify and | |
626 | * fail any probe registration in the prohibited area | |
627 | */ | |
628 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { | |
629 | if (kb->start_addr) { | |
630 | if (addr >= kb->start_addr && | |
631 | addr < (kb->start_addr + kb->range)) | |
632 | return -EINVAL; | |
633 | } | |
634 | } | |
d0aaff97 PP |
635 | return 0; |
636 | } | |
637 | ||
b2a5cd69 MH |
638 | /* |
639 | * If we have a symbol_name argument, look it up and add the offset field | |
640 | * to it. This way, we can specify a relative address to a symbol. | |
641 | */ | |
642 | static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p) | |
643 | { | |
644 | kprobe_opcode_t *addr = p->addr; | |
645 | if (p->symbol_name) { | |
646 | if (addr) | |
647 | return NULL; | |
648 | kprobe_lookup_name(p->symbol_name, addr); | |
649 | } | |
650 | ||
651 | if (!addr) | |
652 | return NULL; | |
653 | return (kprobe_opcode_t *)(((char *)addr) + p->offset); | |
654 | } | |
655 | ||
1f0ab409 AM |
656 | /* Check passed kprobe is valid and return kprobe in kprobe_table. */ |
657 | static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p) | |
658 | { | |
659 | struct kprobe *old_p, *list_p; | |
660 | ||
661 | old_p = get_kprobe(p->addr); | |
662 | if (unlikely(!old_p)) | |
663 | return NULL; | |
664 | ||
665 | if (p != old_p) { | |
666 | list_for_each_entry_rcu(list_p, &old_p->list, list) | |
667 | if (list_p == p) | |
668 | /* kprobe p is a valid probe */ | |
669 | goto valid; | |
670 | return NULL; | |
671 | } | |
672 | valid: | |
673 | return old_p; | |
674 | } | |
675 | ||
676 | /* Return error if the kprobe is being re-registered */ | |
677 | static inline int check_kprobe_rereg(struct kprobe *p) | |
678 | { | |
679 | int ret = 0; | |
680 | struct kprobe *old_p; | |
681 | ||
682 | mutex_lock(&kprobe_mutex); | |
683 | old_p = __get_valid_kprobe(p); | |
684 | if (old_p) | |
685 | ret = -EINVAL; | |
686 | mutex_unlock(&kprobe_mutex); | |
687 | return ret; | |
688 | } | |
689 | ||
49ad2fd7 | 690 | int __kprobes register_kprobe(struct kprobe *p) |
1da177e4 LT |
691 | { |
692 | int ret = 0; | |
64f562c6 | 693 | struct kprobe *old_p; |
df019b1d | 694 | struct module *probed_mod; |
b2a5cd69 | 695 | kprobe_opcode_t *addr; |
b3e55c72 | 696 | |
b2a5cd69 MH |
697 | addr = kprobe_addr(p); |
698 | if (!addr) | |
3a872d89 | 699 | return -EINVAL; |
b2a5cd69 | 700 | p->addr = addr; |
3a872d89 | 701 | |
1f0ab409 AM |
702 | ret = check_kprobe_rereg(p); |
703 | if (ret) | |
704 | return ret; | |
705 | ||
a189d035 | 706 | preempt_disable(); |
ec30c5f3 | 707 | if (!kernel_text_address((unsigned long) p->addr) || |
4554dbcb MH |
708 | in_kprobes_functions((unsigned long) p->addr) || |
709 | ftrace_text_reserved(p->addr, p->addr)) { | |
a189d035 | 710 | preempt_enable(); |
b3e55c72 | 711 | return -EINVAL; |
a189d035 | 712 | } |
b3e55c72 | 713 | |
de5bd88d MH |
714 | /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */ |
715 | p->flags &= KPROBE_FLAG_DISABLED; | |
716 | ||
6f716acd CH |
717 | /* |
718 | * Check if are we probing a module. | |
719 | */ | |
a189d035 | 720 | probed_mod = __module_text_address((unsigned long) p->addr); |
6f716acd | 721 | if (probed_mod) { |
6f716acd | 722 | /* |
e8386a0c MH |
723 | * We must hold a refcount of the probed module while updating |
724 | * its code to prohibit unexpected unloading. | |
df019b1d | 725 | */ |
49ad2fd7 MH |
726 | if (unlikely(!try_module_get(probed_mod))) { |
727 | preempt_enable(); | |
728 | return -EINVAL; | |
729 | } | |
f24659d9 MH |
730 | /* |
731 | * If the module freed .init.text, we couldn't insert | |
732 | * kprobes in there. | |
733 | */ | |
734 | if (within_module_init((unsigned long)p->addr, probed_mod) && | |
735 | probed_mod->state != MODULE_STATE_COMING) { | |
736 | module_put(probed_mod); | |
737 | preempt_enable(); | |
738 | return -EINVAL; | |
739 | } | |
df019b1d | 740 | } |
a189d035 | 741 | preempt_enable(); |
1da177e4 | 742 | |
3516a460 | 743 | p->nmissed = 0; |
9861668f | 744 | INIT_LIST_HEAD(&p->list); |
7a7d1cf9 | 745 | mutex_lock(&kprobe_mutex); |
64f562c6 AM |
746 | old_p = get_kprobe(p->addr); |
747 | if (old_p) { | |
748 | ret = register_aggr_kprobe(old_p, p); | |
1da177e4 LT |
749 | goto out; |
750 | } | |
1da177e4 | 751 | |
4460fdad | 752 | mutex_lock(&text_mutex); |
6f716acd CH |
753 | ret = arch_prepare_kprobe(p); |
754 | if (ret) | |
4460fdad | 755 | goto out_unlock_text; |
49a2a1b8 | 756 | |
64f562c6 | 757 | INIT_HLIST_NODE(&p->hlist); |
3516a460 | 758 | hlist_add_head_rcu(&p->hlist, |
1da177e4 LT |
759 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); |
760 | ||
de5bd88d | 761 | if (!kprobes_all_disarmed && !kprobe_disabled(p)) |
bf8f6e5b | 762 | arch_arm_kprobe(p); |
74a0b576 | 763 | |
4460fdad MD |
764 | out_unlock_text: |
765 | mutex_unlock(&text_mutex); | |
1da177e4 | 766 | out: |
7a7d1cf9 | 767 | mutex_unlock(&kprobe_mutex); |
49a2a1b8 | 768 | |
e8386a0c | 769 | if (probed_mod) |
df019b1d | 770 | module_put(probed_mod); |
e8386a0c | 771 | |
1da177e4 LT |
772 | return ret; |
773 | } | |
99081ab5 | 774 | EXPORT_SYMBOL_GPL(register_kprobe); |
1da177e4 | 775 | |
de5bd88d MH |
776 | /* |
777 | * Unregister a kprobe without a scheduler synchronization. | |
778 | */ | |
779 | static int __kprobes __unregister_kprobe_top(struct kprobe *p) | |
780 | { | |
781 | struct kprobe *old_p, *list_p; | |
782 | ||
783 | old_p = __get_valid_kprobe(p); | |
784 | if (old_p == NULL) | |
785 | return -EINVAL; | |
786 | ||
6f716acd CH |
787 | if (old_p == p || |
788 | (old_p->pre_handler == aggr_pre_handler && | |
9861668f | 789 | list_is_singular(&old_p->list))) { |
bf8f6e5b AM |
790 | /* |
791 | * Only probe on the hash list. Disarm only if kprobes are | |
e8386a0c MH |
792 | * enabled and not gone - otherwise, the breakpoint would |
793 | * already have been removed. We save on flushing icache. | |
bf8f6e5b | 794 | */ |
201517a7 MH |
795 | if (!kprobes_all_disarmed && !kprobe_disabled(old_p)) |
796 | disarm_kprobe(p); | |
49a2a1b8 | 797 | hlist_del_rcu(&old_p->hlist); |
49a2a1b8 | 798 | } else { |
e8386a0c | 799 | if (p->break_handler && !kprobe_gone(p)) |
9861668f | 800 | old_p->break_handler = NULL; |
e8386a0c | 801 | if (p->post_handler && !kprobe_gone(p)) { |
9861668f MH |
802 | list_for_each_entry_rcu(list_p, &old_p->list, list) { |
803 | if ((list_p != p) && (list_p->post_handler)) | |
804 | goto noclean; | |
805 | } | |
806 | old_p->post_handler = NULL; | |
807 | } | |
808 | noclean: | |
49a2a1b8 | 809 | list_del_rcu(&p->list); |
de5bd88d MH |
810 | if (!kprobe_disabled(old_p)) { |
811 | try_to_disable_aggr_kprobe(old_p); | |
812 | if (!kprobes_all_disarmed && kprobe_disabled(old_p)) | |
201517a7 | 813 | disarm_kprobe(old_p); |
de5bd88d | 814 | } |
49a2a1b8 | 815 | } |
9861668f MH |
816 | return 0; |
817 | } | |
3516a460 | 818 | |
9861668f MH |
819 | static void __kprobes __unregister_kprobe_bottom(struct kprobe *p) |
820 | { | |
9861668f | 821 | struct kprobe *old_p; |
b3e55c72 | 822 | |
e8386a0c | 823 | if (list_empty(&p->list)) |
0498b635 | 824 | arch_remove_kprobe(p); |
e8386a0c MH |
825 | else if (list_is_singular(&p->list)) { |
826 | /* "p" is the last child of an aggr_kprobe */ | |
827 | old_p = list_entry(p->list.next, struct kprobe, list); | |
828 | list_del(&p->list); | |
829 | arch_remove_kprobe(old_p); | |
830 | kfree(old_p); | |
9861668f MH |
831 | } |
832 | } | |
833 | ||
49ad2fd7 | 834 | int __kprobes register_kprobes(struct kprobe **kps, int num) |
9861668f MH |
835 | { |
836 | int i, ret = 0; | |
837 | ||
838 | if (num <= 0) | |
839 | return -EINVAL; | |
840 | for (i = 0; i < num; i++) { | |
49ad2fd7 | 841 | ret = register_kprobe(kps[i]); |
67dddaad MH |
842 | if (ret < 0) { |
843 | if (i > 0) | |
844 | unregister_kprobes(kps, i); | |
9861668f | 845 | break; |
36721656 | 846 | } |
49a2a1b8 | 847 | } |
9861668f MH |
848 | return ret; |
849 | } | |
99081ab5 | 850 | EXPORT_SYMBOL_GPL(register_kprobes); |
9861668f | 851 | |
9861668f MH |
852 | void __kprobes unregister_kprobe(struct kprobe *p) |
853 | { | |
854 | unregister_kprobes(&p, 1); | |
855 | } | |
99081ab5 | 856 | EXPORT_SYMBOL_GPL(unregister_kprobe); |
9861668f | 857 | |
9861668f MH |
858 | void __kprobes unregister_kprobes(struct kprobe **kps, int num) |
859 | { | |
860 | int i; | |
861 | ||
862 | if (num <= 0) | |
863 | return; | |
864 | mutex_lock(&kprobe_mutex); | |
865 | for (i = 0; i < num; i++) | |
866 | if (__unregister_kprobe_top(kps[i]) < 0) | |
867 | kps[i]->addr = NULL; | |
868 | mutex_unlock(&kprobe_mutex); | |
869 | ||
870 | synchronize_sched(); | |
871 | for (i = 0; i < num; i++) | |
872 | if (kps[i]->addr) | |
873 | __unregister_kprobe_bottom(kps[i]); | |
1da177e4 | 874 | } |
99081ab5 | 875 | EXPORT_SYMBOL_GPL(unregister_kprobes); |
1da177e4 LT |
876 | |
877 | static struct notifier_block kprobe_exceptions_nb = { | |
3d5631e0 AK |
878 | .notifier_call = kprobe_exceptions_notify, |
879 | .priority = 0x7fffffff /* we need to be notified first */ | |
880 | }; | |
881 | ||
3d7e3382 ME |
882 | unsigned long __weak arch_deref_entry_point(void *entry) |
883 | { | |
884 | return (unsigned long)entry; | |
885 | } | |
1da177e4 | 886 | |
49ad2fd7 | 887 | int __kprobes register_jprobes(struct jprobe **jps, int num) |
1da177e4 | 888 | { |
26b31c19 MH |
889 | struct jprobe *jp; |
890 | int ret = 0, i; | |
3d7e3382 | 891 | |
26b31c19 | 892 | if (num <= 0) |
3d7e3382 | 893 | return -EINVAL; |
26b31c19 MH |
894 | for (i = 0; i < num; i++) { |
895 | unsigned long addr; | |
896 | jp = jps[i]; | |
897 | addr = arch_deref_entry_point(jp->entry); | |
898 | ||
899 | if (!kernel_text_address(addr)) | |
900 | ret = -EINVAL; | |
901 | else { | |
902 | /* Todo: Verify probepoint is a function entry point */ | |
903 | jp->kp.pre_handler = setjmp_pre_handler; | |
904 | jp->kp.break_handler = longjmp_break_handler; | |
49ad2fd7 | 905 | ret = register_kprobe(&jp->kp); |
26b31c19 | 906 | } |
67dddaad MH |
907 | if (ret < 0) { |
908 | if (i > 0) | |
909 | unregister_jprobes(jps, i); | |
26b31c19 MH |
910 | break; |
911 | } | |
912 | } | |
913 | return ret; | |
914 | } | |
99081ab5 | 915 | EXPORT_SYMBOL_GPL(register_jprobes); |
3d7e3382 | 916 | |
26b31c19 MH |
917 | int __kprobes register_jprobe(struct jprobe *jp) |
918 | { | |
49ad2fd7 | 919 | return register_jprobes(&jp, 1); |
1da177e4 | 920 | } |
99081ab5 | 921 | EXPORT_SYMBOL_GPL(register_jprobe); |
1da177e4 | 922 | |
d0aaff97 | 923 | void __kprobes unregister_jprobe(struct jprobe *jp) |
1da177e4 | 924 | { |
26b31c19 MH |
925 | unregister_jprobes(&jp, 1); |
926 | } | |
99081ab5 | 927 | EXPORT_SYMBOL_GPL(unregister_jprobe); |
26b31c19 | 928 | |
26b31c19 MH |
929 | void __kprobes unregister_jprobes(struct jprobe **jps, int num) |
930 | { | |
931 | int i; | |
932 | ||
933 | if (num <= 0) | |
934 | return; | |
935 | mutex_lock(&kprobe_mutex); | |
936 | for (i = 0; i < num; i++) | |
937 | if (__unregister_kprobe_top(&jps[i]->kp) < 0) | |
938 | jps[i]->kp.addr = NULL; | |
939 | mutex_unlock(&kprobe_mutex); | |
940 | ||
941 | synchronize_sched(); | |
942 | for (i = 0; i < num; i++) { | |
943 | if (jps[i]->kp.addr) | |
944 | __unregister_kprobe_bottom(&jps[i]->kp); | |
945 | } | |
1da177e4 | 946 | } |
99081ab5 | 947 | EXPORT_SYMBOL_GPL(unregister_jprobes); |
1da177e4 | 948 | |
9edddaa2 | 949 | #ifdef CONFIG_KRETPROBES |
e65cefe8 AB |
950 | /* |
951 | * This kprobe pre_handler is registered with every kretprobe. When probe | |
952 | * hits it will set up the return probe. | |
953 | */ | |
954 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, | |
955 | struct pt_regs *regs) | |
956 | { | |
957 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); | |
ef53d9c5 S |
958 | unsigned long hash, flags = 0; |
959 | struct kretprobe_instance *ri; | |
e65cefe8 AB |
960 | |
961 | /*TODO: consider to only swap the RA after the last pre_handler fired */ | |
ef53d9c5 S |
962 | hash = hash_ptr(current, KPROBE_HASH_BITS); |
963 | spin_lock_irqsave(&rp->lock, flags); | |
4c4308cb | 964 | if (!hlist_empty(&rp->free_instances)) { |
4c4308cb | 965 | ri = hlist_entry(rp->free_instances.first, |
ef53d9c5 S |
966 | struct kretprobe_instance, hlist); |
967 | hlist_del(&ri->hlist); | |
968 | spin_unlock_irqrestore(&rp->lock, flags); | |
969 | ||
4c4308cb CH |
970 | ri->rp = rp; |
971 | ri->task = current; | |
f47cd9b5 | 972 | |
f02b8624 | 973 | if (rp->entry_handler && rp->entry_handler(ri, regs)) |
f47cd9b5 | 974 | return 0; |
f47cd9b5 | 975 | |
4c4308cb CH |
976 | arch_prepare_kretprobe(ri, regs); |
977 | ||
978 | /* XXX(hch): why is there no hlist_move_head? */ | |
ef53d9c5 S |
979 | INIT_HLIST_NODE(&ri->hlist); |
980 | kretprobe_table_lock(hash, &flags); | |
981 | hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]); | |
982 | kretprobe_table_unlock(hash, &flags); | |
983 | } else { | |
4c4308cb | 984 | rp->nmissed++; |
ef53d9c5 S |
985 | spin_unlock_irqrestore(&rp->lock, flags); |
986 | } | |
e65cefe8 AB |
987 | return 0; |
988 | } | |
989 | ||
49ad2fd7 | 990 | int __kprobes register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
991 | { |
992 | int ret = 0; | |
993 | struct kretprobe_instance *inst; | |
994 | int i; | |
b2a5cd69 | 995 | void *addr; |
f438d914 MH |
996 | |
997 | if (kretprobe_blacklist_size) { | |
b2a5cd69 MH |
998 | addr = kprobe_addr(&rp->kp); |
999 | if (!addr) | |
1000 | return -EINVAL; | |
f438d914 MH |
1001 | |
1002 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
1003 | if (kretprobe_blacklist[i].addr == addr) | |
1004 | return -EINVAL; | |
1005 | } | |
1006 | } | |
b94cce92 HN |
1007 | |
1008 | rp->kp.pre_handler = pre_handler_kretprobe; | |
7522a842 AM |
1009 | rp->kp.post_handler = NULL; |
1010 | rp->kp.fault_handler = NULL; | |
1011 | rp->kp.break_handler = NULL; | |
b94cce92 HN |
1012 | |
1013 | /* Pre-allocate memory for max kretprobe instances */ | |
1014 | if (rp->maxactive <= 0) { | |
1015 | #ifdef CONFIG_PREEMPT | |
c2ef6661 | 1016 | rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus()); |
b94cce92 | 1017 | #else |
4dae560f | 1018 | rp->maxactive = num_possible_cpus(); |
b94cce92 HN |
1019 | #endif |
1020 | } | |
ef53d9c5 | 1021 | spin_lock_init(&rp->lock); |
b94cce92 HN |
1022 | INIT_HLIST_HEAD(&rp->free_instances); |
1023 | for (i = 0; i < rp->maxactive; i++) { | |
f47cd9b5 AS |
1024 | inst = kmalloc(sizeof(struct kretprobe_instance) + |
1025 | rp->data_size, GFP_KERNEL); | |
b94cce92 HN |
1026 | if (inst == NULL) { |
1027 | free_rp_inst(rp); | |
1028 | return -ENOMEM; | |
1029 | } | |
ef53d9c5 S |
1030 | INIT_HLIST_NODE(&inst->hlist); |
1031 | hlist_add_head(&inst->hlist, &rp->free_instances); | |
b94cce92 HN |
1032 | } |
1033 | ||
1034 | rp->nmissed = 0; | |
1035 | /* Establish function entry probe point */ | |
49ad2fd7 | 1036 | ret = register_kprobe(&rp->kp); |
4a296e07 | 1037 | if (ret != 0) |
b94cce92 HN |
1038 | free_rp_inst(rp); |
1039 | return ret; | |
1040 | } | |
99081ab5 | 1041 | EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce92 | 1042 | |
49ad2fd7 | 1043 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) |
4a296e07 MH |
1044 | { |
1045 | int ret = 0, i; | |
1046 | ||
1047 | if (num <= 0) | |
1048 | return -EINVAL; | |
1049 | for (i = 0; i < num; i++) { | |
49ad2fd7 | 1050 | ret = register_kretprobe(rps[i]); |
67dddaad MH |
1051 | if (ret < 0) { |
1052 | if (i > 0) | |
1053 | unregister_kretprobes(rps, i); | |
4a296e07 MH |
1054 | break; |
1055 | } | |
1056 | } | |
1057 | return ret; | |
1058 | } | |
99081ab5 | 1059 | EXPORT_SYMBOL_GPL(register_kretprobes); |
4a296e07 | 1060 | |
4a296e07 MH |
1061 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
1062 | { | |
1063 | unregister_kretprobes(&rp, 1); | |
1064 | } | |
99081ab5 | 1065 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
4a296e07 | 1066 | |
4a296e07 MH |
1067 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) |
1068 | { | |
1069 | int i; | |
1070 | ||
1071 | if (num <= 0) | |
1072 | return; | |
1073 | mutex_lock(&kprobe_mutex); | |
1074 | for (i = 0; i < num; i++) | |
1075 | if (__unregister_kprobe_top(&rps[i]->kp) < 0) | |
1076 | rps[i]->kp.addr = NULL; | |
1077 | mutex_unlock(&kprobe_mutex); | |
1078 | ||
1079 | synchronize_sched(); | |
1080 | for (i = 0; i < num; i++) { | |
1081 | if (rps[i]->kp.addr) { | |
1082 | __unregister_kprobe_bottom(&rps[i]->kp); | |
1083 | cleanup_rp_inst(rps[i]); | |
1084 | } | |
1085 | } | |
1086 | } | |
99081ab5 | 1087 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4a296e07 | 1088 | |
9edddaa2 | 1089 | #else /* CONFIG_KRETPROBES */ |
d0aaff97 | 1090 | int __kprobes register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
1091 | { |
1092 | return -ENOSYS; | |
1093 | } | |
99081ab5 | 1094 | EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce92 | 1095 | |
4a296e07 | 1096 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) |
346fd59b | 1097 | { |
4a296e07 | 1098 | return -ENOSYS; |
346fd59b | 1099 | } |
99081ab5 MH |
1100 | EXPORT_SYMBOL_GPL(register_kretprobes); |
1101 | ||
d0aaff97 | 1102 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
b94cce92 | 1103 | { |
4a296e07 | 1104 | } |
99081ab5 | 1105 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
b94cce92 | 1106 | |
4a296e07 MH |
1107 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) |
1108 | { | |
1109 | } | |
99081ab5 | 1110 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4c4308cb | 1111 | |
4a296e07 MH |
1112 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, |
1113 | struct pt_regs *regs) | |
1114 | { | |
1115 | return 0; | |
b94cce92 HN |
1116 | } |
1117 | ||
4a296e07 MH |
1118 | #endif /* CONFIG_KRETPROBES */ |
1119 | ||
e8386a0c MH |
1120 | /* Set the kprobe gone and remove its instruction buffer. */ |
1121 | static void __kprobes kill_kprobe(struct kprobe *p) | |
1122 | { | |
1123 | struct kprobe *kp; | |
de5bd88d | 1124 | |
e8386a0c MH |
1125 | p->flags |= KPROBE_FLAG_GONE; |
1126 | if (p->pre_handler == aggr_pre_handler) { | |
1127 | /* | |
1128 | * If this is an aggr_kprobe, we have to list all the | |
1129 | * chained probes and mark them GONE. | |
1130 | */ | |
1131 | list_for_each_entry_rcu(kp, &p->list, list) | |
1132 | kp->flags |= KPROBE_FLAG_GONE; | |
1133 | p->post_handler = NULL; | |
1134 | p->break_handler = NULL; | |
1135 | } | |
1136 | /* | |
1137 | * Here, we can remove insn_slot safely, because no thread calls | |
1138 | * the original probed function (which will be freed soon) any more. | |
1139 | */ | |
1140 | arch_remove_kprobe(p); | |
1141 | } | |
1142 | ||
24851d24 FW |
1143 | void __kprobes dump_kprobe(struct kprobe *kp) |
1144 | { | |
1145 | printk(KERN_WARNING "Dumping kprobe:\n"); | |
1146 | printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n", | |
1147 | kp->symbol_name, kp->addr, kp->offset); | |
1148 | } | |
1149 | ||
e8386a0c MH |
1150 | /* Module notifier call back, checking kprobes on the module */ |
1151 | static int __kprobes kprobes_module_callback(struct notifier_block *nb, | |
1152 | unsigned long val, void *data) | |
1153 | { | |
1154 | struct module *mod = data; | |
1155 | struct hlist_head *head; | |
1156 | struct hlist_node *node; | |
1157 | struct kprobe *p; | |
1158 | unsigned int i; | |
f24659d9 | 1159 | int checkcore = (val == MODULE_STATE_GOING); |
e8386a0c | 1160 | |
f24659d9 | 1161 | if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE) |
e8386a0c MH |
1162 | return NOTIFY_DONE; |
1163 | ||
1164 | /* | |
f24659d9 MH |
1165 | * When MODULE_STATE_GOING was notified, both of module .text and |
1166 | * .init.text sections would be freed. When MODULE_STATE_LIVE was | |
1167 | * notified, only .init.text section would be freed. We need to | |
1168 | * disable kprobes which have been inserted in the sections. | |
e8386a0c MH |
1169 | */ |
1170 | mutex_lock(&kprobe_mutex); | |
1171 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { | |
1172 | head = &kprobe_table[i]; | |
1173 | hlist_for_each_entry_rcu(p, node, head, hlist) | |
f24659d9 MH |
1174 | if (within_module_init((unsigned long)p->addr, mod) || |
1175 | (checkcore && | |
1176 | within_module_core((unsigned long)p->addr, mod))) { | |
e8386a0c MH |
1177 | /* |
1178 | * The vaddr this probe is installed will soon | |
1179 | * be vfreed buy not synced to disk. Hence, | |
1180 | * disarming the breakpoint isn't needed. | |
1181 | */ | |
1182 | kill_kprobe(p); | |
1183 | } | |
1184 | } | |
1185 | mutex_unlock(&kprobe_mutex); | |
1186 | return NOTIFY_DONE; | |
1187 | } | |
1188 | ||
1189 | static struct notifier_block kprobe_module_nb = { | |
1190 | .notifier_call = kprobes_module_callback, | |
1191 | .priority = 0 | |
1192 | }; | |
1193 | ||
1da177e4 LT |
1194 | static int __init init_kprobes(void) |
1195 | { | |
1196 | int i, err = 0; | |
3d8d996e SD |
1197 | unsigned long offset = 0, size = 0; |
1198 | char *modname, namebuf[128]; | |
1199 | const char *symbol_name; | |
1200 | void *addr; | |
1201 | struct kprobe_blackpoint *kb; | |
1da177e4 LT |
1202 | |
1203 | /* FIXME allocate the probe table, currently defined statically */ | |
1204 | /* initialize all list heads */ | |
b94cce92 | 1205 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1da177e4 | 1206 | INIT_HLIST_HEAD(&kprobe_table[i]); |
b94cce92 | 1207 | INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
ef53d9c5 | 1208 | spin_lock_init(&(kretprobe_table_locks[i].lock)); |
b94cce92 | 1209 | } |
1da177e4 | 1210 | |
3d8d996e SD |
1211 | /* |
1212 | * Lookup and populate the kprobe_blacklist. | |
1213 | * | |
1214 | * Unlike the kretprobe blacklist, we'll need to determine | |
1215 | * the range of addresses that belong to the said functions, | |
1216 | * since a kprobe need not necessarily be at the beginning | |
1217 | * of a function. | |
1218 | */ | |
1219 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { | |
1220 | kprobe_lookup_name(kb->name, addr); | |
1221 | if (!addr) | |
1222 | continue; | |
1223 | ||
1224 | kb->start_addr = (unsigned long)addr; | |
1225 | symbol_name = kallsyms_lookup(kb->start_addr, | |
1226 | &size, &offset, &modname, namebuf); | |
1227 | if (!symbol_name) | |
1228 | kb->range = 0; | |
1229 | else | |
1230 | kb->range = size; | |
1231 | } | |
1232 | ||
f438d914 MH |
1233 | if (kretprobe_blacklist_size) { |
1234 | /* lookup the function address from its name */ | |
1235 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
1236 | kprobe_lookup_name(kretprobe_blacklist[i].name, | |
1237 | kretprobe_blacklist[i].addr); | |
1238 | if (!kretprobe_blacklist[i].addr) | |
1239 | printk("kretprobe: lookup failed: %s\n", | |
1240 | kretprobe_blacklist[i].name); | |
1241 | } | |
1242 | } | |
1243 | ||
e579abeb MH |
1244 | /* By default, kprobes are armed */ |
1245 | kprobes_all_disarmed = false; | |
bf8f6e5b | 1246 | |
6772926b | 1247 | err = arch_init_kprobes(); |
802eae7c RL |
1248 | if (!err) |
1249 | err = register_die_notifier(&kprobe_exceptions_nb); | |
e8386a0c MH |
1250 | if (!err) |
1251 | err = register_module_notifier(&kprobe_module_nb); | |
1252 | ||
ef53d9c5 | 1253 | kprobes_initialized = (err == 0); |
802eae7c | 1254 | |
8c1c9356 AM |
1255 | if (!err) |
1256 | init_test_probes(); | |
1da177e4 LT |
1257 | return err; |
1258 | } | |
1259 | ||
346fd59b SD |
1260 | #ifdef CONFIG_DEBUG_FS |
1261 | static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p, | |
bf8f6e5b | 1262 | const char *sym, int offset,char *modname) |
346fd59b SD |
1263 | { |
1264 | char *kprobe_type; | |
1265 | ||
1266 | if (p->pre_handler == pre_handler_kretprobe) | |
1267 | kprobe_type = "r"; | |
1268 | else if (p->pre_handler == setjmp_pre_handler) | |
1269 | kprobe_type = "j"; | |
1270 | else | |
1271 | kprobe_type = "k"; | |
1272 | if (sym) | |
de5bd88d MH |
1273 | seq_printf(pi, "%p %s %s+0x%x %s %s%s\n", |
1274 | p->addr, kprobe_type, sym, offset, | |
1275 | (modname ? modname : " "), | |
1276 | (kprobe_gone(p) ? "[GONE]" : ""), | |
1277 | ((kprobe_disabled(p) && !kprobe_gone(p)) ? | |
1278 | "[DISABLED]" : "")); | |
346fd59b | 1279 | else |
de5bd88d MH |
1280 | seq_printf(pi, "%p %s %p %s%s\n", |
1281 | p->addr, kprobe_type, p->addr, | |
1282 | (kprobe_gone(p) ? "[GONE]" : ""), | |
1283 | ((kprobe_disabled(p) && !kprobe_gone(p)) ? | |
1284 | "[DISABLED]" : "")); | |
346fd59b SD |
1285 | } |
1286 | ||
1287 | static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos) | |
1288 | { | |
1289 | return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; | |
1290 | } | |
1291 | ||
1292 | static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) | |
1293 | { | |
1294 | (*pos)++; | |
1295 | if (*pos >= KPROBE_TABLE_SIZE) | |
1296 | return NULL; | |
1297 | return pos; | |
1298 | } | |
1299 | ||
1300 | static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v) | |
1301 | { | |
1302 | /* Nothing to do */ | |
1303 | } | |
1304 | ||
1305 | static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v) | |
1306 | { | |
1307 | struct hlist_head *head; | |
1308 | struct hlist_node *node; | |
1309 | struct kprobe *p, *kp; | |
1310 | const char *sym = NULL; | |
1311 | unsigned int i = *(loff_t *) v; | |
ffb45122 | 1312 | unsigned long offset = 0; |
346fd59b SD |
1313 | char *modname, namebuf[128]; |
1314 | ||
1315 | head = &kprobe_table[i]; | |
1316 | preempt_disable(); | |
1317 | hlist_for_each_entry_rcu(p, node, head, hlist) { | |
ffb45122 | 1318 | sym = kallsyms_lookup((unsigned long)p->addr, NULL, |
346fd59b SD |
1319 | &offset, &modname, namebuf); |
1320 | if (p->pre_handler == aggr_pre_handler) { | |
1321 | list_for_each_entry_rcu(kp, &p->list, list) | |
1322 | report_probe(pi, kp, sym, offset, modname); | |
1323 | } else | |
1324 | report_probe(pi, p, sym, offset, modname); | |
1325 | } | |
1326 | preempt_enable(); | |
1327 | return 0; | |
1328 | } | |
1329 | ||
88e9d34c | 1330 | static const struct seq_operations kprobes_seq_ops = { |
346fd59b SD |
1331 | .start = kprobe_seq_start, |
1332 | .next = kprobe_seq_next, | |
1333 | .stop = kprobe_seq_stop, | |
1334 | .show = show_kprobe_addr | |
1335 | }; | |
1336 | ||
1337 | static int __kprobes kprobes_open(struct inode *inode, struct file *filp) | |
1338 | { | |
1339 | return seq_open(filp, &kprobes_seq_ops); | |
1340 | } | |
1341 | ||
828c0950 | 1342 | static const struct file_operations debugfs_kprobes_operations = { |
346fd59b SD |
1343 | .open = kprobes_open, |
1344 | .read = seq_read, | |
1345 | .llseek = seq_lseek, | |
1346 | .release = seq_release, | |
1347 | }; | |
1348 | ||
de5bd88d MH |
1349 | /* Disable one kprobe */ |
1350 | int __kprobes disable_kprobe(struct kprobe *kp) | |
1351 | { | |
1352 | int ret = 0; | |
1353 | struct kprobe *p; | |
1354 | ||
1355 | mutex_lock(&kprobe_mutex); | |
1356 | ||
1357 | /* Check whether specified probe is valid. */ | |
1358 | p = __get_valid_kprobe(kp); | |
1359 | if (unlikely(p == NULL)) { | |
1360 | ret = -EINVAL; | |
1361 | goto out; | |
1362 | } | |
1363 | ||
1364 | /* If the probe is already disabled (or gone), just return */ | |
1365 | if (kprobe_disabled(kp)) | |
1366 | goto out; | |
1367 | ||
1368 | kp->flags |= KPROBE_FLAG_DISABLED; | |
1369 | if (p != kp) | |
1370 | /* When kp != p, p is always enabled. */ | |
1371 | try_to_disable_aggr_kprobe(p); | |
1372 | ||
1373 | if (!kprobes_all_disarmed && kprobe_disabled(p)) | |
201517a7 | 1374 | disarm_kprobe(p); |
de5bd88d MH |
1375 | out: |
1376 | mutex_unlock(&kprobe_mutex); | |
1377 | return ret; | |
1378 | } | |
1379 | EXPORT_SYMBOL_GPL(disable_kprobe); | |
1380 | ||
1381 | /* Enable one kprobe */ | |
1382 | int __kprobes enable_kprobe(struct kprobe *kp) | |
1383 | { | |
1384 | int ret = 0; | |
1385 | struct kprobe *p; | |
1386 | ||
1387 | mutex_lock(&kprobe_mutex); | |
1388 | ||
1389 | /* Check whether specified probe is valid. */ | |
1390 | p = __get_valid_kprobe(kp); | |
1391 | if (unlikely(p == NULL)) { | |
1392 | ret = -EINVAL; | |
1393 | goto out; | |
1394 | } | |
1395 | ||
1396 | if (kprobe_gone(kp)) { | |
1397 | /* This kprobe has gone, we couldn't enable it. */ | |
1398 | ret = -EINVAL; | |
1399 | goto out; | |
1400 | } | |
1401 | ||
1402 | if (!kprobes_all_disarmed && kprobe_disabled(p)) | |
201517a7 | 1403 | arm_kprobe(p); |
de5bd88d MH |
1404 | |
1405 | p->flags &= ~KPROBE_FLAG_DISABLED; | |
1406 | if (p != kp) | |
1407 | kp->flags &= ~KPROBE_FLAG_DISABLED; | |
1408 | out: | |
1409 | mutex_unlock(&kprobe_mutex); | |
1410 | return ret; | |
1411 | } | |
1412 | EXPORT_SYMBOL_GPL(enable_kprobe); | |
1413 | ||
e579abeb | 1414 | static void __kprobes arm_all_kprobes(void) |
bf8f6e5b AM |
1415 | { |
1416 | struct hlist_head *head; | |
1417 | struct hlist_node *node; | |
1418 | struct kprobe *p; | |
1419 | unsigned int i; | |
1420 | ||
1421 | mutex_lock(&kprobe_mutex); | |
1422 | ||
e579abeb MH |
1423 | /* If kprobes are armed, just return */ |
1424 | if (!kprobes_all_disarmed) | |
bf8f6e5b AM |
1425 | goto already_enabled; |
1426 | ||
4460fdad | 1427 | mutex_lock(&text_mutex); |
bf8f6e5b AM |
1428 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1429 | head = &kprobe_table[i]; | |
1430 | hlist_for_each_entry_rcu(p, node, head, hlist) | |
de5bd88d | 1431 | if (!kprobe_disabled(p)) |
e8386a0c | 1432 | arch_arm_kprobe(p); |
bf8f6e5b | 1433 | } |
4460fdad | 1434 | mutex_unlock(&text_mutex); |
bf8f6e5b | 1435 | |
e579abeb | 1436 | kprobes_all_disarmed = false; |
bf8f6e5b AM |
1437 | printk(KERN_INFO "Kprobes globally enabled\n"); |
1438 | ||
1439 | already_enabled: | |
1440 | mutex_unlock(&kprobe_mutex); | |
1441 | return; | |
1442 | } | |
1443 | ||
e579abeb | 1444 | static void __kprobes disarm_all_kprobes(void) |
bf8f6e5b AM |
1445 | { |
1446 | struct hlist_head *head; | |
1447 | struct hlist_node *node; | |
1448 | struct kprobe *p; | |
1449 | unsigned int i; | |
1450 | ||
1451 | mutex_lock(&kprobe_mutex); | |
1452 | ||
e579abeb MH |
1453 | /* If kprobes are already disarmed, just return */ |
1454 | if (kprobes_all_disarmed) | |
bf8f6e5b AM |
1455 | goto already_disabled; |
1456 | ||
e579abeb | 1457 | kprobes_all_disarmed = true; |
bf8f6e5b | 1458 | printk(KERN_INFO "Kprobes globally disabled\n"); |
4460fdad | 1459 | mutex_lock(&text_mutex); |
bf8f6e5b AM |
1460 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1461 | head = &kprobe_table[i]; | |
1462 | hlist_for_each_entry_rcu(p, node, head, hlist) { | |
de5bd88d | 1463 | if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) |
bf8f6e5b AM |
1464 | arch_disarm_kprobe(p); |
1465 | } | |
1466 | } | |
1467 | ||
4460fdad | 1468 | mutex_unlock(&text_mutex); |
bf8f6e5b AM |
1469 | mutex_unlock(&kprobe_mutex); |
1470 | /* Allow all currently running kprobes to complete */ | |
1471 | synchronize_sched(); | |
74a0b576 | 1472 | return; |
bf8f6e5b AM |
1473 | |
1474 | already_disabled: | |
1475 | mutex_unlock(&kprobe_mutex); | |
1476 | return; | |
1477 | } | |
1478 | ||
1479 | /* | |
1480 | * XXX: The debugfs bool file interface doesn't allow for callbacks | |
1481 | * when the bool state is switched. We can reuse that facility when | |
1482 | * available | |
1483 | */ | |
1484 | static ssize_t read_enabled_file_bool(struct file *file, | |
1485 | char __user *user_buf, size_t count, loff_t *ppos) | |
1486 | { | |
1487 | char buf[3]; | |
1488 | ||
e579abeb | 1489 | if (!kprobes_all_disarmed) |
bf8f6e5b AM |
1490 | buf[0] = '1'; |
1491 | else | |
1492 | buf[0] = '0'; | |
1493 | buf[1] = '\n'; | |
1494 | buf[2] = 0x00; | |
1495 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); | |
1496 | } | |
1497 | ||
1498 | static ssize_t write_enabled_file_bool(struct file *file, | |
1499 | const char __user *user_buf, size_t count, loff_t *ppos) | |
1500 | { | |
1501 | char buf[32]; | |
1502 | int buf_size; | |
1503 | ||
1504 | buf_size = min(count, (sizeof(buf)-1)); | |
1505 | if (copy_from_user(buf, user_buf, buf_size)) | |
1506 | return -EFAULT; | |
1507 | ||
1508 | switch (buf[0]) { | |
1509 | case 'y': | |
1510 | case 'Y': | |
1511 | case '1': | |
e579abeb | 1512 | arm_all_kprobes(); |
bf8f6e5b AM |
1513 | break; |
1514 | case 'n': | |
1515 | case 'N': | |
1516 | case '0': | |
e579abeb | 1517 | disarm_all_kprobes(); |
bf8f6e5b AM |
1518 | break; |
1519 | } | |
1520 | ||
1521 | return count; | |
1522 | } | |
1523 | ||
828c0950 | 1524 | static const struct file_operations fops_kp = { |
bf8f6e5b AM |
1525 | .read = read_enabled_file_bool, |
1526 | .write = write_enabled_file_bool, | |
1527 | }; | |
1528 | ||
346fd59b SD |
1529 | static int __kprobes debugfs_kprobe_init(void) |
1530 | { | |
1531 | struct dentry *dir, *file; | |
bf8f6e5b | 1532 | unsigned int value = 1; |
346fd59b SD |
1533 | |
1534 | dir = debugfs_create_dir("kprobes", NULL); | |
1535 | if (!dir) | |
1536 | return -ENOMEM; | |
1537 | ||
e3869792 | 1538 | file = debugfs_create_file("list", 0444, dir, NULL, |
346fd59b SD |
1539 | &debugfs_kprobes_operations); |
1540 | if (!file) { | |
1541 | debugfs_remove(dir); | |
1542 | return -ENOMEM; | |
1543 | } | |
1544 | ||
bf8f6e5b AM |
1545 | file = debugfs_create_file("enabled", 0600, dir, |
1546 | &value, &fops_kp); | |
1547 | if (!file) { | |
1548 | debugfs_remove(dir); | |
1549 | return -ENOMEM; | |
1550 | } | |
1551 | ||
346fd59b SD |
1552 | return 0; |
1553 | } | |
1554 | ||
1555 | late_initcall(debugfs_kprobe_init); | |
1556 | #endif /* CONFIG_DEBUG_FS */ | |
1557 | ||
1558 | module_init(init_kprobes); | |
1da177e4 | 1559 | |
99081ab5 | 1560 | /* defined in arch/.../kernel/kprobes.c */ |
1da177e4 | 1561 | EXPORT_SYMBOL_GPL(jprobe_return); |