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> |
bf8f6e5b | 46 | |
d0aaff97 | 47 | #include <asm-generic/sections.h> |
1da177e4 LT |
48 | #include <asm/cacheflush.h> |
49 | #include <asm/errno.h> | |
bf8f6e5b | 50 | #include <asm/uaccess.h> |
1da177e4 LT |
51 | |
52 | #define KPROBE_HASH_BITS 6 | |
53 | #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS) | |
54 | ||
3a872d89 AM |
55 | |
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 | ||
ef53d9c5 | 65 | static int kprobes_initialized; |
1da177e4 | 66 | static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; |
b94cce92 | 67 | static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; |
1da177e4 | 68 | |
bf8f6e5b AM |
69 | /* NOTE: change this value only with kprobe_mutex held */ |
70 | static bool kprobe_enabled; | |
71 | ||
12941560 | 72 | static DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */ |
e6584523 | 73 | static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; |
ef53d9c5 | 74 | static struct { |
7e036d04 | 75 | spinlock_t lock ____cacheline_aligned_in_smp; |
ef53d9c5 S |
76 | } kretprobe_table_locks[KPROBE_TABLE_SIZE]; |
77 | ||
78 | static spinlock_t *kretprobe_table_lock_ptr(unsigned long hash) | |
79 | { | |
80 | return &(kretprobe_table_locks[hash].lock); | |
81 | } | |
1da177e4 | 82 | |
3d8d996e SD |
83 | /* |
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 | */ | |
544304b2 | 90 | static struct kprobe_blackpoint kprobe_blacklist[] = { |
3d8d996e SD |
91 | {"preempt_schedule",}, |
92 | {NULL} /* Terminator */ | |
93 | }; | |
94 | ||
2d14e39d | 95 | #ifdef __ARCH_WANT_KPROBES_INSN_SLOT |
9ec4b1f3 AM |
96 | /* |
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 | ||
104 | struct 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; | |
b4c6c34a | 109 | int ngarbage; |
9ec4b1f3 AM |
110 | }; |
111 | ||
ab40c5c6 MH |
112 | enum kprobe_slot_state { |
113 | SLOT_CLEAN = 0, | |
114 | SLOT_DIRTY = 1, | |
115 | SLOT_USED = 2, | |
116 | }; | |
117 | ||
12941560 | 118 | static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_pages */ |
9ec4b1f3 | 119 | static struct hlist_head kprobe_insn_pages; |
b4c6c34a MH |
120 | static int kprobe_garbage_slots; |
121 | static int collect_garbage_slots(void); | |
122 | ||
123 | static 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 | } | |
139 | loop_end: | |
140 | thaw_processes(); | |
141 | #else | |
142 | synchronize_sched(); | |
143 | #endif | |
144 | return ret; | |
145 | } | |
9ec4b1f3 AM |
146 | |
147 | /** | |
12941560 | 148 | * __get_insn_slot() - Find a slot on an executable page for an instruction. |
9ec4b1f3 AM |
149 | * We allocate an executable page if there's no room on existing ones. |
150 | */ | |
12941560 | 151 | static kprobe_opcode_t __kprobes *__get_insn_slot(void) |
9ec4b1f3 AM |
152 | { |
153 | struct kprobe_insn_page *kip; | |
154 | struct hlist_node *pos; | |
155 | ||
6f716acd | 156 | retry: |
b0bb5016 | 157 | hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) { |
9ec4b1f3 AM |
158 | if (kip->nused < INSNS_PER_PAGE) { |
159 | int i; | |
160 | for (i = 0; i < INSNS_PER_PAGE; i++) { | |
ab40c5c6 MH |
161 | if (kip->slot_used[i] == SLOT_CLEAN) { |
162 | kip->slot_used[i] = SLOT_USED; | |
9ec4b1f3 AM |
163 | 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 | ||
b4c6c34a MH |
172 | /* 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. */ | |
9ec4b1f3 | 177 | kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL); |
6f716acd | 178 | if (!kip) |
9ec4b1f3 | 179 | return NULL; |
9ec4b1f3 AM |
180 | |
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); | |
ab40c5c6 MH |
193 | memset(kip->slot_used, SLOT_CLEAN, INSNS_PER_PAGE); |
194 | kip->slot_used[0] = SLOT_USED; | |
9ec4b1f3 | 195 | kip->nused = 1; |
b4c6c34a | 196 | kip->ngarbage = 0; |
9ec4b1f3 AM |
197 | return kip->insns; |
198 | } | |
199 | ||
12941560 MH |
200 | kprobe_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 | ||
b4c6c34a MH |
209 | /* Return 1 if all garbages are collected, otherwise 0. */ |
210 | static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx) | |
211 | { | |
ab40c5c6 | 212 | kip->slot_used[idx] = SLOT_CLEAN; |
b4c6c34a MH |
213 | 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 | ||
235 | static int __kprobes collect_garbage_slots(void) | |
236 | { | |
237 | struct kprobe_insn_page *kip; | |
238 | struct hlist_node *pos, *next; | |
12941560 | 239 | int safety; |
b4c6c34a MH |
240 | |
241 | /* Ensure no-one is preepmted on the garbages */ | |
12941560 MH |
242 | mutex_unlock(&kprobe_insn_mutex); |
243 | safety = check_safety(); | |
244 | mutex_lock(&kprobe_insn_mutex); | |
245 | if (safety != 0) | |
b4c6c34a MH |
246 | return -EAGAIN; |
247 | ||
b0bb5016 | 248 | hlist_for_each_entry_safe(kip, pos, next, &kprobe_insn_pages, hlist) { |
b4c6c34a | 249 | int i; |
b4c6c34a MH |
250 | if (kip->ngarbage == 0) |
251 | continue; | |
252 | kip->ngarbage = 0; /* we will collect all garbages */ | |
253 | for (i = 0; i < INSNS_PER_PAGE; i++) { | |
ab40c5c6 | 254 | if (kip->slot_used[i] == SLOT_DIRTY && |
b4c6c34a MH |
255 | collect_one_slot(kip, i)) |
256 | break; | |
257 | } | |
258 | } | |
259 | kprobe_garbage_slots = 0; | |
260 | return 0; | |
261 | } | |
262 | ||
263 | void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty) | |
9ec4b1f3 AM |
264 | { |
265 | struct kprobe_insn_page *kip; | |
266 | struct hlist_node *pos; | |
267 | ||
12941560 | 268 | mutex_lock(&kprobe_insn_mutex); |
b0bb5016 | 269 | hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) { |
9ec4b1f3 AM |
270 | if (kip->insns <= slot && |
271 | slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) { | |
272 | int i = (slot - kip->insns) / MAX_INSN_SIZE; | |
b4c6c34a | 273 | if (dirty) { |
ab40c5c6 | 274 | kip->slot_used[i] = SLOT_DIRTY; |
b4c6c34a MH |
275 | kip->ngarbage++; |
276 | } else { | |
277 | collect_one_slot(kip, i); | |
9ec4b1f3 | 278 | } |
b4c6c34a | 279 | break; |
9ec4b1f3 AM |
280 | } |
281 | } | |
6f716acd CH |
282 | |
283 | if (dirty && ++kprobe_garbage_slots > INSNS_PER_PAGE) | |
b4c6c34a | 284 | collect_garbage_slots(); |
12941560 MH |
285 | |
286 | mutex_unlock(&kprobe_insn_mutex); | |
9ec4b1f3 | 287 | } |
2d14e39d | 288 | #endif |
9ec4b1f3 | 289 | |
e6584523 AM |
290 | /* We have preemption disabled.. so it is safe to use __ versions */ |
291 | static inline void set_kprobe_instance(struct kprobe *kp) | |
292 | { | |
293 | __get_cpu_var(kprobe_instance) = kp; | |
294 | } | |
295 | ||
296 | static inline void reset_kprobe_instance(void) | |
297 | { | |
298 | __get_cpu_var(kprobe_instance) = NULL; | |
299 | } | |
300 | ||
3516a460 AM |
301 | /* |
302 | * This routine is called either: | |
49a2a1b8 | 303 | * - under the kprobe_mutex - during kprobe_[un]register() |
3516a460 | 304 | * OR |
d217d545 | 305 | * - with preemption disabled - from arch/xxx/kernel/kprobes.c |
3516a460 | 306 | */ |
d0aaff97 | 307 | struct kprobe __kprobes *get_kprobe(void *addr) |
1da177e4 LT |
308 | { |
309 | struct hlist_head *head; | |
310 | struct hlist_node *node; | |
3516a460 | 311 | struct kprobe *p; |
1da177e4 LT |
312 | |
313 | head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; | |
3516a460 | 314 | hlist_for_each_entry_rcu(p, node, head, hlist) { |
1da177e4 LT |
315 | if (p->addr == addr) |
316 | return p; | |
317 | } | |
318 | return NULL; | |
319 | } | |
320 | ||
64f562c6 AM |
321 | /* |
322 | * Aggregate handlers for multiple kprobes support - these handlers | |
323 | * take care of invoking the individual kprobe handlers on p->list | |
324 | */ | |
d0aaff97 | 325 | static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
64f562c6 AM |
326 | { |
327 | struct kprobe *kp; | |
328 | ||
3516a460 | 329 | list_for_each_entry_rcu(kp, &p->list, list) { |
64f562c6 | 330 | if (kp->pre_handler) { |
e6584523 | 331 | set_kprobe_instance(kp); |
8b0914ea PP |
332 | if (kp->pre_handler(kp, regs)) |
333 | return 1; | |
64f562c6 | 334 | } |
e6584523 | 335 | reset_kprobe_instance(); |
64f562c6 AM |
336 | } |
337 | return 0; | |
338 | } | |
339 | ||
d0aaff97 PP |
340 | static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
341 | unsigned long flags) | |
64f562c6 AM |
342 | { |
343 | struct kprobe *kp; | |
344 | ||
3516a460 | 345 | list_for_each_entry_rcu(kp, &p->list, list) { |
64f562c6 | 346 | if (kp->post_handler) { |
e6584523 | 347 | set_kprobe_instance(kp); |
64f562c6 | 348 | kp->post_handler(kp, regs, flags); |
e6584523 | 349 | reset_kprobe_instance(); |
64f562c6 AM |
350 | } |
351 | } | |
64f562c6 AM |
352 | } |
353 | ||
d0aaff97 PP |
354 | static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, |
355 | int trapnr) | |
64f562c6 | 356 | { |
e6584523 AM |
357 | struct kprobe *cur = __get_cpu_var(kprobe_instance); |
358 | ||
64f562c6 AM |
359 | /* |
360 | * if we faulted "during" the execution of a user specified | |
361 | * probe handler, invoke just that probe's fault handler | |
362 | */ | |
e6584523 AM |
363 | if (cur && cur->fault_handler) { |
364 | if (cur->fault_handler(cur, regs, trapnr)) | |
64f562c6 AM |
365 | return 1; |
366 | } | |
367 | return 0; | |
368 | } | |
369 | ||
d0aaff97 | 370 | static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs) |
8b0914ea | 371 | { |
e6584523 AM |
372 | 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; | |
8b0914ea | 378 | } |
e6584523 AM |
379 | reset_kprobe_instance(); |
380 | return ret; | |
8b0914ea PP |
381 | } |
382 | ||
bf8d5c52 KA |
383 | /* Walks the list and increments nmissed count for multiprobe case */ |
384 | void __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 | ||
99219a3f | 396 | void __kprobes recycle_rp_inst(struct kretprobe_instance *ri, |
397 | struct hlist_head *head) | |
b94cce92 | 398 | { |
ef53d9c5 S |
399 | struct kretprobe *rp = ri->rp; |
400 | ||
b94cce92 HN |
401 | /* remove rp inst off the rprobe_inst_table */ |
402 | hlist_del(&ri->hlist); | |
ef53d9c5 S |
403 | 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); | |
b94cce92 HN |
408 | } else |
409 | /* Unregistering */ | |
99219a3f | 410 | hlist_add_head(&ri->hlist, head); |
b94cce92 HN |
411 | } |
412 | ||
ef53d9c5 S |
413 | void kretprobe_hash_lock(struct task_struct *tsk, |
414 | struct hlist_head **head, unsigned long *flags) | |
415 | { | |
416 | 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 | ||
2b252c54 | 424 | static void kretprobe_table_lock(unsigned long hash, unsigned long *flags) |
b94cce92 | 425 | { |
ef53d9c5 S |
426 | spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
427 | spin_lock_irqsave(hlist_lock, *flags); | |
428 | } | |
429 | ||
430 | void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags) | |
431 | { | |
432 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); | |
433 | spinlock_t *hlist_lock; | |
434 | ||
435 | hlist_lock = kretprobe_table_lock_ptr(hash); | |
436 | spin_unlock_irqrestore(hlist_lock, *flags); | |
437 | } | |
438 | ||
439 | void kretprobe_table_unlock(unsigned long hash, unsigned long *flags) | |
440 | { | |
441 | spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); | |
442 | spin_unlock_irqrestore(hlist_lock, *flags); | |
b94cce92 HN |
443 | } |
444 | ||
b94cce92 | 445 | /* |
c6fd91f0 | 446 | * This function is called from finish_task_switch when task tk becomes dead, |
447 | * so that we can recycle any function-return probe instances associated | |
448 | * with this task. These left over instances represent probed functions | |
449 | * that have been called but will never return. | |
b94cce92 | 450 | */ |
d0aaff97 | 451 | void __kprobes kprobe_flush_task(struct task_struct *tk) |
b94cce92 | 452 | { |
62c27be0 | 453 | struct kretprobe_instance *ri; |
99219a3f | 454 | struct hlist_head *head, empty_rp; |
802eae7c | 455 | struct hlist_node *node, *tmp; |
ef53d9c5 | 456 | unsigned long hash, flags = 0; |
802eae7c | 457 | |
ef53d9c5 S |
458 | if (unlikely(!kprobes_initialized)) |
459 | /* Early boot. kretprobe_table_locks not yet initialized. */ | |
460 | return; | |
461 | ||
462 | hash = hash_ptr(tk, KPROBE_HASH_BITS); | |
463 | head = &kretprobe_inst_table[hash]; | |
464 | kretprobe_table_lock(hash, &flags); | |
62c27be0 | 465 | hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { |
466 | if (ri->task == tk) | |
99219a3f | 467 | recycle_rp_inst(ri, &empty_rp); |
62c27be0 | 468 | } |
ef53d9c5 S |
469 | kretprobe_table_unlock(hash, &flags); |
470 | INIT_HLIST_HEAD(&empty_rp); | |
99219a3f | 471 | hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { |
472 | hlist_del(&ri->hlist); | |
473 | kfree(ri); | |
474 | } | |
b94cce92 HN |
475 | } |
476 | ||
b94cce92 HN |
477 | static inline void free_rp_inst(struct kretprobe *rp) |
478 | { | |
479 | struct kretprobe_instance *ri; | |
4c4308cb CH |
480 | struct hlist_node *pos, *next; |
481 | ||
ef53d9c5 S |
482 | hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) { |
483 | hlist_del(&ri->hlist); | |
b94cce92 HN |
484 | kfree(ri); |
485 | } | |
486 | } | |
487 | ||
4a296e07 MH |
488 | static void __kprobes cleanup_rp_inst(struct kretprobe *rp) |
489 | { | |
ef53d9c5 | 490 | unsigned long flags, hash; |
4a296e07 MH |
491 | struct kretprobe_instance *ri; |
492 | struct hlist_node *pos, *next; | |
ef53d9c5 S |
493 | struct hlist_head *head; |
494 | ||
4a296e07 | 495 | /* No race here */ |
ef53d9c5 S |
496 | for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) { |
497 | kretprobe_table_lock(hash, &flags); | |
498 | head = &kretprobe_inst_table[hash]; | |
499 | hlist_for_each_entry_safe(ri, pos, next, head, hlist) { | |
500 | if (ri->rp == rp) | |
501 | ri->rp = NULL; | |
502 | } | |
503 | kretprobe_table_unlock(hash, &flags); | |
4a296e07 | 504 | } |
4a296e07 MH |
505 | free_rp_inst(rp); |
506 | } | |
507 | ||
8b0914ea PP |
508 | /* |
509 | * Keep all fields in the kprobe consistent | |
510 | */ | |
511 | static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p) | |
512 | { | |
513 | memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t)); | |
514 | memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn)); | |
515 | } | |
516 | ||
517 | /* | |
518 | * Add the new probe to old_p->list. Fail if this is the | |
519 | * second jprobe at the address - two jprobes can't coexist | |
520 | */ | |
d0aaff97 | 521 | static int __kprobes add_new_kprobe(struct kprobe *old_p, struct kprobe *p) |
8b0914ea | 522 | { |
8b0914ea | 523 | if (p->break_handler) { |
36721656 | 524 | if (old_p->break_handler) |
525 | return -EEXIST; | |
3516a460 | 526 | list_add_tail_rcu(&p->list, &old_p->list); |
36721656 | 527 | old_p->break_handler = aggr_break_handler; |
8b0914ea | 528 | } else |
3516a460 | 529 | list_add_rcu(&p->list, &old_p->list); |
36721656 | 530 | if (p->post_handler && !old_p->post_handler) |
531 | old_p->post_handler = aggr_post_handler; | |
8b0914ea PP |
532 | return 0; |
533 | } | |
534 | ||
64f562c6 AM |
535 | /* |
536 | * Fill in the required fields of the "manager kprobe". Replace the | |
537 | * earlier kprobe in the hlist with the manager kprobe | |
538 | */ | |
539 | static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p) | |
540 | { | |
8b0914ea | 541 | copy_kprobe(p, ap); |
a9ad965e | 542 | flush_insn_slot(ap); |
64f562c6 | 543 | ap->addr = p->addr; |
64f562c6 | 544 | ap->pre_handler = aggr_pre_handler; |
64f562c6 | 545 | ap->fault_handler = aggr_fault_handler; |
36721656 | 546 | if (p->post_handler) |
547 | ap->post_handler = aggr_post_handler; | |
548 | if (p->break_handler) | |
549 | ap->break_handler = aggr_break_handler; | |
64f562c6 AM |
550 | |
551 | INIT_LIST_HEAD(&ap->list); | |
3516a460 | 552 | list_add_rcu(&p->list, &ap->list); |
64f562c6 | 553 | |
adad0f33 | 554 | hlist_replace_rcu(&p->hlist, &ap->hlist); |
64f562c6 AM |
555 | } |
556 | ||
557 | /* | |
558 | * This is the second or subsequent kprobe at the address - handle | |
559 | * the intricacies | |
64f562c6 | 560 | */ |
d0aaff97 PP |
561 | static int __kprobes register_aggr_kprobe(struct kprobe *old_p, |
562 | struct kprobe *p) | |
64f562c6 AM |
563 | { |
564 | int ret = 0; | |
565 | struct kprobe *ap; | |
566 | ||
8b0914ea PP |
567 | if (old_p->pre_handler == aggr_pre_handler) { |
568 | copy_kprobe(old_p, p); | |
569 | ret = add_new_kprobe(old_p, p); | |
64f562c6 | 570 | } else { |
a0d50069 | 571 | ap = kzalloc(sizeof(struct kprobe), GFP_KERNEL); |
64f562c6 AM |
572 | if (!ap) |
573 | return -ENOMEM; | |
574 | add_aggr_kprobe(ap, old_p); | |
8b0914ea PP |
575 | copy_kprobe(ap, p); |
576 | ret = add_new_kprobe(ap, p); | |
64f562c6 AM |
577 | } |
578 | return ret; | |
579 | } | |
580 | ||
d0aaff97 PP |
581 | static int __kprobes in_kprobes_functions(unsigned long addr) |
582 | { | |
3d8d996e SD |
583 | struct kprobe_blackpoint *kb; |
584 | ||
6f716acd CH |
585 | if (addr >= (unsigned long)__kprobes_text_start && |
586 | addr < (unsigned long)__kprobes_text_end) | |
d0aaff97 | 587 | return -EINVAL; |
3d8d996e SD |
588 | /* |
589 | * If there exists a kprobe_blacklist, verify and | |
590 | * fail any probe registration in the prohibited area | |
591 | */ | |
592 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { | |
593 | if (kb->start_addr) { | |
594 | if (addr >= kb->start_addr && | |
595 | addr < (kb->start_addr + kb->range)) | |
596 | return -EINVAL; | |
597 | } | |
598 | } | |
d0aaff97 PP |
599 | return 0; |
600 | } | |
601 | ||
b2a5cd69 MH |
602 | /* |
603 | * If we have a symbol_name argument, look it up and add the offset field | |
604 | * to it. This way, we can specify a relative address to a symbol. | |
605 | */ | |
606 | static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p) | |
607 | { | |
608 | kprobe_opcode_t *addr = p->addr; | |
609 | if (p->symbol_name) { | |
610 | if (addr) | |
611 | return NULL; | |
612 | kprobe_lookup_name(p->symbol_name, addr); | |
613 | } | |
614 | ||
615 | if (!addr) | |
616 | return NULL; | |
617 | return (kprobe_opcode_t *)(((char *)addr) + p->offset); | |
618 | } | |
619 | ||
df019b1d KA |
620 | static int __kprobes __register_kprobe(struct kprobe *p, |
621 | unsigned long called_from) | |
1da177e4 LT |
622 | { |
623 | int ret = 0; | |
64f562c6 | 624 | struct kprobe *old_p; |
df019b1d | 625 | struct module *probed_mod; |
b2a5cd69 | 626 | kprobe_opcode_t *addr; |
b3e55c72 | 627 | |
b2a5cd69 MH |
628 | addr = kprobe_addr(p); |
629 | if (!addr) | |
3a872d89 | 630 | return -EINVAL; |
b2a5cd69 | 631 | p->addr = addr; |
3a872d89 | 632 | |
a189d035 MH |
633 | preempt_disable(); |
634 | if (!__kernel_text_address((unsigned long) p->addr) || | |
635 | in_kprobes_functions((unsigned long) p->addr)) { | |
636 | preempt_enable(); | |
b3e55c72 | 637 | return -EINVAL; |
a189d035 | 638 | } |
b3e55c72 | 639 | |
df019b1d | 640 | p->mod_refcounted = 0; |
6f716acd CH |
641 | |
642 | /* | |
643 | * Check if are we probing a module. | |
644 | */ | |
a189d035 | 645 | probed_mod = __module_text_address((unsigned long) p->addr); |
6f716acd | 646 | if (probed_mod) { |
a189d035 MH |
647 | struct module *calling_mod; |
648 | calling_mod = __module_text_address(called_from); | |
6f716acd CH |
649 | /* |
650 | * We must allow modules to probe themself and in this case | |
651 | * avoid incrementing the module refcount, so as to allow | |
652 | * unloading of self probing modules. | |
df019b1d | 653 | */ |
bc2f7015 | 654 | if (calling_mod != probed_mod) { |
a189d035 MH |
655 | if (unlikely(!try_module_get(probed_mod))) { |
656 | preempt_enable(); | |
df019b1d | 657 | return -EINVAL; |
a189d035 | 658 | } |
df019b1d KA |
659 | p->mod_refcounted = 1; |
660 | } else | |
661 | probed_mod = NULL; | |
662 | } | |
a189d035 | 663 | preempt_enable(); |
1da177e4 | 664 | |
3516a460 | 665 | p->nmissed = 0; |
9861668f | 666 | INIT_LIST_HEAD(&p->list); |
7a7d1cf9 | 667 | mutex_lock(&kprobe_mutex); |
64f562c6 AM |
668 | old_p = get_kprobe(p->addr); |
669 | if (old_p) { | |
670 | ret = register_aggr_kprobe(old_p, p); | |
1da177e4 LT |
671 | goto out; |
672 | } | |
1da177e4 | 673 | |
6f716acd CH |
674 | ret = arch_prepare_kprobe(p); |
675 | if (ret) | |
49a2a1b8 AK |
676 | goto out; |
677 | ||
64f562c6 | 678 | INIT_HLIST_NODE(&p->hlist); |
3516a460 | 679 | hlist_add_head_rcu(&p->hlist, |
1da177e4 LT |
680 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); |
681 | ||
74a0b576 | 682 | if (kprobe_enabled) |
bf8f6e5b | 683 | arch_arm_kprobe(p); |
74a0b576 | 684 | |
1da177e4 | 685 | out: |
7a7d1cf9 | 686 | mutex_unlock(&kprobe_mutex); |
49a2a1b8 | 687 | |
df019b1d KA |
688 | if (ret && probed_mod) |
689 | module_put(probed_mod); | |
1da177e4 LT |
690 | return ret; |
691 | } | |
692 | ||
9861668f MH |
693 | /* |
694 | * Unregister a kprobe without a scheduler synchronization. | |
695 | */ | |
696 | static int __kprobes __unregister_kprobe_top(struct kprobe *p) | |
1da177e4 | 697 | { |
f709b122 | 698 | struct kprobe *old_p, *list_p; |
64f562c6 | 699 | |
64f562c6 | 700 | old_p = get_kprobe(p->addr); |
9861668f MH |
701 | if (unlikely(!old_p)) |
702 | return -EINVAL; | |
703 | ||
f709b122 KA |
704 | if (p != old_p) { |
705 | list_for_each_entry_rcu(list_p, &old_p->list, list) | |
706 | if (list_p == p) | |
707 | /* kprobe p is a valid probe */ | |
708 | goto valid_p; | |
9861668f | 709 | return -EINVAL; |
f709b122 KA |
710 | } |
711 | valid_p: | |
6f716acd CH |
712 | if (old_p == p || |
713 | (old_p->pre_handler == aggr_pre_handler && | |
9861668f | 714 | list_is_singular(&old_p->list))) { |
bf8f6e5b AM |
715 | /* |
716 | * Only probe on the hash list. Disarm only if kprobes are | |
717 | * enabled - otherwise, the breakpoint would already have | |
718 | * been removed. We save on flushing icache. | |
719 | */ | |
720 | if (kprobe_enabled) | |
721 | arch_disarm_kprobe(p); | |
49a2a1b8 | 722 | hlist_del_rcu(&old_p->hlist); |
49a2a1b8 | 723 | } else { |
9861668f MH |
724 | if (p->break_handler) |
725 | old_p->break_handler = NULL; | |
726 | if (p->post_handler) { | |
727 | list_for_each_entry_rcu(list_p, &old_p->list, list) { | |
728 | if ((list_p != p) && (list_p->post_handler)) | |
729 | goto noclean; | |
730 | } | |
731 | old_p->post_handler = NULL; | |
732 | } | |
733 | noclean: | |
49a2a1b8 | 734 | list_del_rcu(&p->list); |
49a2a1b8 | 735 | } |
9861668f MH |
736 | return 0; |
737 | } | |
3516a460 | 738 | |
9861668f MH |
739 | static void __kprobes __unregister_kprobe_bottom(struct kprobe *p) |
740 | { | |
741 | struct module *mod; | |
742 | struct kprobe *old_p; | |
b3e55c72 | 743 | |
6f716acd | 744 | if (p->mod_refcounted) { |
a189d035 MH |
745 | /* |
746 | * Since we've already incremented refcount, | |
747 | * we don't need to disable preemption. | |
748 | */ | |
6f716acd CH |
749 | mod = module_text_address((unsigned long)p->addr); |
750 | if (mod) | |
751 | module_put(mod); | |
752 | } | |
b3e55c72 | 753 | |
9861668f MH |
754 | if (list_empty(&p->list) || list_is_singular(&p->list)) { |
755 | if (!list_empty(&p->list)) { | |
756 | /* "p" is the last child of an aggr_kprobe */ | |
757 | old_p = list_entry(p->list.next, struct kprobe, list); | |
758 | list_del(&p->list); | |
3516a460 | 759 | kfree(old_p); |
49a2a1b8 | 760 | } |
0498b635 | 761 | arch_remove_kprobe(p); |
9861668f MH |
762 | } |
763 | } | |
764 | ||
765 | static int __register_kprobes(struct kprobe **kps, int num, | |
766 | unsigned long called_from) | |
767 | { | |
768 | int i, ret = 0; | |
769 | ||
770 | if (num <= 0) | |
771 | return -EINVAL; | |
772 | for (i = 0; i < num; i++) { | |
773 | ret = __register_kprobe(kps[i], called_from); | |
67dddaad MH |
774 | if (ret < 0) { |
775 | if (i > 0) | |
776 | unregister_kprobes(kps, i); | |
9861668f | 777 | break; |
36721656 | 778 | } |
49a2a1b8 | 779 | } |
9861668f MH |
780 | return ret; |
781 | } | |
782 | ||
783 | /* | |
784 | * Registration and unregistration functions for kprobe. | |
785 | */ | |
786 | int __kprobes register_kprobe(struct kprobe *p) | |
787 | { | |
788 | return __register_kprobes(&p, 1, | |
789 | (unsigned long)__builtin_return_address(0)); | |
790 | } | |
791 | ||
792 | void __kprobes unregister_kprobe(struct kprobe *p) | |
793 | { | |
794 | unregister_kprobes(&p, 1); | |
795 | } | |
796 | ||
797 | int __kprobes register_kprobes(struct kprobe **kps, int num) | |
798 | { | |
799 | return __register_kprobes(kps, num, | |
800 | (unsigned long)__builtin_return_address(0)); | |
801 | } | |
802 | ||
803 | void __kprobes unregister_kprobes(struct kprobe **kps, int num) | |
804 | { | |
805 | int i; | |
806 | ||
807 | if (num <= 0) | |
808 | return; | |
809 | mutex_lock(&kprobe_mutex); | |
810 | for (i = 0; i < num; i++) | |
811 | if (__unregister_kprobe_top(kps[i]) < 0) | |
812 | kps[i]->addr = NULL; | |
813 | mutex_unlock(&kprobe_mutex); | |
814 | ||
815 | synchronize_sched(); | |
816 | for (i = 0; i < num; i++) | |
817 | if (kps[i]->addr) | |
818 | __unregister_kprobe_bottom(kps[i]); | |
1da177e4 LT |
819 | } |
820 | ||
821 | static struct notifier_block kprobe_exceptions_nb = { | |
3d5631e0 AK |
822 | .notifier_call = kprobe_exceptions_notify, |
823 | .priority = 0x7fffffff /* we need to be notified first */ | |
824 | }; | |
825 | ||
3d7e3382 ME |
826 | unsigned long __weak arch_deref_entry_point(void *entry) |
827 | { | |
828 | return (unsigned long)entry; | |
829 | } | |
1da177e4 | 830 | |
26b31c19 MH |
831 | static int __register_jprobes(struct jprobe **jps, int num, |
832 | unsigned long called_from) | |
1da177e4 | 833 | { |
26b31c19 MH |
834 | struct jprobe *jp; |
835 | int ret = 0, i; | |
3d7e3382 | 836 | |
26b31c19 | 837 | if (num <= 0) |
3d7e3382 | 838 | return -EINVAL; |
26b31c19 MH |
839 | for (i = 0; i < num; i++) { |
840 | unsigned long addr; | |
841 | jp = jps[i]; | |
842 | addr = arch_deref_entry_point(jp->entry); | |
843 | ||
844 | if (!kernel_text_address(addr)) | |
845 | ret = -EINVAL; | |
846 | else { | |
847 | /* Todo: Verify probepoint is a function entry point */ | |
848 | jp->kp.pre_handler = setjmp_pre_handler; | |
849 | jp->kp.break_handler = longjmp_break_handler; | |
850 | ret = __register_kprobe(&jp->kp, called_from); | |
851 | } | |
67dddaad MH |
852 | if (ret < 0) { |
853 | if (i > 0) | |
854 | unregister_jprobes(jps, i); | |
26b31c19 MH |
855 | break; |
856 | } | |
857 | } | |
858 | return ret; | |
859 | } | |
3d7e3382 | 860 | |
26b31c19 MH |
861 | int __kprobes register_jprobe(struct jprobe *jp) |
862 | { | |
863 | return __register_jprobes(&jp, 1, | |
df019b1d | 864 | (unsigned long)__builtin_return_address(0)); |
1da177e4 LT |
865 | } |
866 | ||
d0aaff97 | 867 | void __kprobes unregister_jprobe(struct jprobe *jp) |
1da177e4 | 868 | { |
26b31c19 MH |
869 | unregister_jprobes(&jp, 1); |
870 | } | |
871 | ||
872 | int __kprobes register_jprobes(struct jprobe **jps, int num) | |
873 | { | |
874 | return __register_jprobes(jps, num, | |
875 | (unsigned long)__builtin_return_address(0)); | |
876 | } | |
877 | ||
878 | void __kprobes unregister_jprobes(struct jprobe **jps, int num) | |
879 | { | |
880 | int i; | |
881 | ||
882 | if (num <= 0) | |
883 | return; | |
884 | mutex_lock(&kprobe_mutex); | |
885 | for (i = 0; i < num; i++) | |
886 | if (__unregister_kprobe_top(&jps[i]->kp) < 0) | |
887 | jps[i]->kp.addr = NULL; | |
888 | mutex_unlock(&kprobe_mutex); | |
889 | ||
890 | synchronize_sched(); | |
891 | for (i = 0; i < num; i++) { | |
892 | if (jps[i]->kp.addr) | |
893 | __unregister_kprobe_bottom(&jps[i]->kp); | |
894 | } | |
1da177e4 LT |
895 | } |
896 | ||
9edddaa2 | 897 | #ifdef CONFIG_KRETPROBES |
e65cefe8 AB |
898 | /* |
899 | * This kprobe pre_handler is registered with every kretprobe. When probe | |
900 | * hits it will set up the return probe. | |
901 | */ | |
902 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, | |
903 | struct pt_regs *regs) | |
904 | { | |
905 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); | |
ef53d9c5 S |
906 | unsigned long hash, flags = 0; |
907 | struct kretprobe_instance *ri; | |
e65cefe8 AB |
908 | |
909 | /*TODO: consider to only swap the RA after the last pre_handler fired */ | |
ef53d9c5 S |
910 | hash = hash_ptr(current, KPROBE_HASH_BITS); |
911 | spin_lock_irqsave(&rp->lock, flags); | |
4c4308cb | 912 | if (!hlist_empty(&rp->free_instances)) { |
4c4308cb | 913 | ri = hlist_entry(rp->free_instances.first, |
ef53d9c5 S |
914 | struct kretprobe_instance, hlist); |
915 | hlist_del(&ri->hlist); | |
916 | spin_unlock_irqrestore(&rp->lock, flags); | |
917 | ||
4c4308cb CH |
918 | ri->rp = rp; |
919 | ri->task = current; | |
f47cd9b5 AS |
920 | |
921 | if (rp->entry_handler && rp->entry_handler(ri, regs)) { | |
ef53d9c5 | 922 | spin_unlock_irqrestore(&rp->lock, flags); |
f47cd9b5 AS |
923 | return 0; |
924 | } | |
925 | ||
4c4308cb CH |
926 | arch_prepare_kretprobe(ri, regs); |
927 | ||
928 | /* XXX(hch): why is there no hlist_move_head? */ | |
ef53d9c5 S |
929 | INIT_HLIST_NODE(&ri->hlist); |
930 | kretprobe_table_lock(hash, &flags); | |
931 | hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]); | |
932 | kretprobe_table_unlock(hash, &flags); | |
933 | } else { | |
4c4308cb | 934 | rp->nmissed++; |
ef53d9c5 S |
935 | spin_unlock_irqrestore(&rp->lock, flags); |
936 | } | |
e65cefe8 AB |
937 | return 0; |
938 | } | |
939 | ||
4a296e07 MH |
940 | static int __kprobes __register_kretprobe(struct kretprobe *rp, |
941 | unsigned long called_from) | |
b94cce92 HN |
942 | { |
943 | int ret = 0; | |
944 | struct kretprobe_instance *inst; | |
945 | int i; | |
b2a5cd69 | 946 | void *addr; |
f438d914 MH |
947 | |
948 | if (kretprobe_blacklist_size) { | |
b2a5cd69 MH |
949 | addr = kprobe_addr(&rp->kp); |
950 | if (!addr) | |
951 | return -EINVAL; | |
f438d914 MH |
952 | |
953 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
954 | if (kretprobe_blacklist[i].addr == addr) | |
955 | return -EINVAL; | |
956 | } | |
957 | } | |
b94cce92 HN |
958 | |
959 | rp->kp.pre_handler = pre_handler_kretprobe; | |
7522a842 AM |
960 | rp->kp.post_handler = NULL; |
961 | rp->kp.fault_handler = NULL; | |
962 | rp->kp.break_handler = NULL; | |
b94cce92 HN |
963 | |
964 | /* Pre-allocate memory for max kretprobe instances */ | |
965 | if (rp->maxactive <= 0) { | |
966 | #ifdef CONFIG_PREEMPT | |
967 | rp->maxactive = max(10, 2 * NR_CPUS); | |
968 | #else | |
969 | rp->maxactive = NR_CPUS; | |
970 | #endif | |
971 | } | |
ef53d9c5 | 972 | spin_lock_init(&rp->lock); |
b94cce92 HN |
973 | INIT_HLIST_HEAD(&rp->free_instances); |
974 | for (i = 0; i < rp->maxactive; i++) { | |
f47cd9b5 AS |
975 | inst = kmalloc(sizeof(struct kretprobe_instance) + |
976 | rp->data_size, GFP_KERNEL); | |
b94cce92 HN |
977 | if (inst == NULL) { |
978 | free_rp_inst(rp); | |
979 | return -ENOMEM; | |
980 | } | |
ef53d9c5 S |
981 | INIT_HLIST_NODE(&inst->hlist); |
982 | hlist_add_head(&inst->hlist, &rp->free_instances); | |
b94cce92 HN |
983 | } |
984 | ||
985 | rp->nmissed = 0; | |
986 | /* Establish function entry probe point */ | |
4a296e07 MH |
987 | ret = __register_kprobe(&rp->kp, called_from); |
988 | if (ret != 0) | |
b94cce92 HN |
989 | free_rp_inst(rp); |
990 | return ret; | |
991 | } | |
992 | ||
4a296e07 MH |
993 | static int __register_kretprobes(struct kretprobe **rps, int num, |
994 | unsigned long called_from) | |
995 | { | |
996 | int ret = 0, i; | |
997 | ||
998 | if (num <= 0) | |
999 | return -EINVAL; | |
1000 | for (i = 0; i < num; i++) { | |
1001 | ret = __register_kretprobe(rps[i], called_from); | |
67dddaad MH |
1002 | if (ret < 0) { |
1003 | if (i > 0) | |
1004 | unregister_kretprobes(rps, i); | |
4a296e07 MH |
1005 | break; |
1006 | } | |
1007 | } | |
1008 | return ret; | |
1009 | } | |
1010 | ||
1011 | int __kprobes register_kretprobe(struct kretprobe *rp) | |
1012 | { | |
1013 | return __register_kretprobes(&rp, 1, | |
1014 | (unsigned long)__builtin_return_address(0)); | |
1015 | } | |
1016 | ||
1017 | void __kprobes unregister_kretprobe(struct kretprobe *rp) | |
1018 | { | |
1019 | unregister_kretprobes(&rp, 1); | |
1020 | } | |
1021 | ||
1022 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) | |
1023 | { | |
1024 | return __register_kretprobes(rps, num, | |
1025 | (unsigned long)__builtin_return_address(0)); | |
1026 | } | |
1027 | ||
1028 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) | |
1029 | { | |
1030 | int i; | |
1031 | ||
1032 | if (num <= 0) | |
1033 | return; | |
1034 | mutex_lock(&kprobe_mutex); | |
1035 | for (i = 0; i < num; i++) | |
1036 | if (__unregister_kprobe_top(&rps[i]->kp) < 0) | |
1037 | rps[i]->kp.addr = NULL; | |
1038 | mutex_unlock(&kprobe_mutex); | |
1039 | ||
1040 | synchronize_sched(); | |
1041 | for (i = 0; i < num; i++) { | |
1042 | if (rps[i]->kp.addr) { | |
1043 | __unregister_kprobe_bottom(&rps[i]->kp); | |
1044 | cleanup_rp_inst(rps[i]); | |
1045 | } | |
1046 | } | |
1047 | } | |
1048 | ||
9edddaa2 | 1049 | #else /* CONFIG_KRETPROBES */ |
d0aaff97 | 1050 | int __kprobes register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
1051 | { |
1052 | return -ENOSYS; | |
1053 | } | |
1054 | ||
4a296e07 | 1055 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) |
346fd59b | 1056 | { |
4a296e07 | 1057 | return -ENOSYS; |
346fd59b | 1058 | } |
d0aaff97 | 1059 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
b94cce92 | 1060 | { |
4a296e07 | 1061 | } |
b94cce92 | 1062 | |
4a296e07 MH |
1063 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) |
1064 | { | |
1065 | } | |
4c4308cb | 1066 | |
4a296e07 MH |
1067 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, |
1068 | struct pt_regs *regs) | |
1069 | { | |
1070 | return 0; | |
b94cce92 HN |
1071 | } |
1072 | ||
4a296e07 MH |
1073 | #endif /* CONFIG_KRETPROBES */ |
1074 | ||
1da177e4 LT |
1075 | static int __init init_kprobes(void) |
1076 | { | |
1077 | int i, err = 0; | |
3d8d996e SD |
1078 | unsigned long offset = 0, size = 0; |
1079 | char *modname, namebuf[128]; | |
1080 | const char *symbol_name; | |
1081 | void *addr; | |
1082 | struct kprobe_blackpoint *kb; | |
1da177e4 LT |
1083 | |
1084 | /* FIXME allocate the probe table, currently defined statically */ | |
1085 | /* initialize all list heads */ | |
b94cce92 | 1086 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1da177e4 | 1087 | INIT_HLIST_HEAD(&kprobe_table[i]); |
b94cce92 | 1088 | INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
ef53d9c5 | 1089 | spin_lock_init(&(kretprobe_table_locks[i].lock)); |
b94cce92 | 1090 | } |
1da177e4 | 1091 | |
3d8d996e SD |
1092 | /* |
1093 | * Lookup and populate the kprobe_blacklist. | |
1094 | * | |
1095 | * Unlike the kretprobe blacklist, we'll need to determine | |
1096 | * the range of addresses that belong to the said functions, | |
1097 | * since a kprobe need not necessarily be at the beginning | |
1098 | * of a function. | |
1099 | */ | |
1100 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { | |
1101 | kprobe_lookup_name(kb->name, addr); | |
1102 | if (!addr) | |
1103 | continue; | |
1104 | ||
1105 | kb->start_addr = (unsigned long)addr; | |
1106 | symbol_name = kallsyms_lookup(kb->start_addr, | |
1107 | &size, &offset, &modname, namebuf); | |
1108 | if (!symbol_name) | |
1109 | kb->range = 0; | |
1110 | else | |
1111 | kb->range = size; | |
1112 | } | |
1113 | ||
f438d914 MH |
1114 | if (kretprobe_blacklist_size) { |
1115 | /* lookup the function address from its name */ | |
1116 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
1117 | kprobe_lookup_name(kretprobe_blacklist[i].name, | |
1118 | kretprobe_blacklist[i].addr); | |
1119 | if (!kretprobe_blacklist[i].addr) | |
1120 | printk("kretprobe: lookup failed: %s\n", | |
1121 | kretprobe_blacklist[i].name); | |
1122 | } | |
1123 | } | |
1124 | ||
bf8f6e5b AM |
1125 | /* By default, kprobes are enabled */ |
1126 | kprobe_enabled = true; | |
1127 | ||
6772926b | 1128 | err = arch_init_kprobes(); |
802eae7c RL |
1129 | if (!err) |
1130 | err = register_die_notifier(&kprobe_exceptions_nb); | |
ef53d9c5 | 1131 | kprobes_initialized = (err == 0); |
802eae7c | 1132 | |
8c1c9356 AM |
1133 | if (!err) |
1134 | init_test_probes(); | |
1da177e4 LT |
1135 | return err; |
1136 | } | |
1137 | ||
346fd59b SD |
1138 | #ifdef CONFIG_DEBUG_FS |
1139 | static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p, | |
bf8f6e5b | 1140 | const char *sym, int offset,char *modname) |
346fd59b SD |
1141 | { |
1142 | char *kprobe_type; | |
1143 | ||
1144 | if (p->pre_handler == pre_handler_kretprobe) | |
1145 | kprobe_type = "r"; | |
1146 | else if (p->pre_handler == setjmp_pre_handler) | |
1147 | kprobe_type = "j"; | |
1148 | else | |
1149 | kprobe_type = "k"; | |
1150 | if (sym) | |
1151 | seq_printf(pi, "%p %s %s+0x%x %s\n", p->addr, kprobe_type, | |
1152 | sym, offset, (modname ? modname : " ")); | |
1153 | else | |
1154 | seq_printf(pi, "%p %s %p\n", p->addr, kprobe_type, p->addr); | |
1155 | } | |
1156 | ||
1157 | static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos) | |
1158 | { | |
1159 | return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; | |
1160 | } | |
1161 | ||
1162 | static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) | |
1163 | { | |
1164 | (*pos)++; | |
1165 | if (*pos >= KPROBE_TABLE_SIZE) | |
1166 | return NULL; | |
1167 | return pos; | |
1168 | } | |
1169 | ||
1170 | static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v) | |
1171 | { | |
1172 | /* Nothing to do */ | |
1173 | } | |
1174 | ||
1175 | static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v) | |
1176 | { | |
1177 | struct hlist_head *head; | |
1178 | struct hlist_node *node; | |
1179 | struct kprobe *p, *kp; | |
1180 | const char *sym = NULL; | |
1181 | unsigned int i = *(loff_t *) v; | |
ffb45122 | 1182 | unsigned long offset = 0; |
346fd59b SD |
1183 | char *modname, namebuf[128]; |
1184 | ||
1185 | head = &kprobe_table[i]; | |
1186 | preempt_disable(); | |
1187 | hlist_for_each_entry_rcu(p, node, head, hlist) { | |
ffb45122 | 1188 | sym = kallsyms_lookup((unsigned long)p->addr, NULL, |
346fd59b SD |
1189 | &offset, &modname, namebuf); |
1190 | if (p->pre_handler == aggr_pre_handler) { | |
1191 | list_for_each_entry_rcu(kp, &p->list, list) | |
1192 | report_probe(pi, kp, sym, offset, modname); | |
1193 | } else | |
1194 | report_probe(pi, p, sym, offset, modname); | |
1195 | } | |
1196 | preempt_enable(); | |
1197 | return 0; | |
1198 | } | |
1199 | ||
1200 | static struct seq_operations kprobes_seq_ops = { | |
1201 | .start = kprobe_seq_start, | |
1202 | .next = kprobe_seq_next, | |
1203 | .stop = kprobe_seq_stop, | |
1204 | .show = show_kprobe_addr | |
1205 | }; | |
1206 | ||
1207 | static int __kprobes kprobes_open(struct inode *inode, struct file *filp) | |
1208 | { | |
1209 | return seq_open(filp, &kprobes_seq_ops); | |
1210 | } | |
1211 | ||
1212 | static struct file_operations debugfs_kprobes_operations = { | |
1213 | .open = kprobes_open, | |
1214 | .read = seq_read, | |
1215 | .llseek = seq_lseek, | |
1216 | .release = seq_release, | |
1217 | }; | |
1218 | ||
bf8f6e5b AM |
1219 | static void __kprobes enable_all_kprobes(void) |
1220 | { | |
1221 | struct hlist_head *head; | |
1222 | struct hlist_node *node; | |
1223 | struct kprobe *p; | |
1224 | unsigned int i; | |
1225 | ||
1226 | mutex_lock(&kprobe_mutex); | |
1227 | ||
1228 | /* If kprobes are already enabled, just return */ | |
1229 | if (kprobe_enabled) | |
1230 | goto already_enabled; | |
1231 | ||
bf8f6e5b AM |
1232 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1233 | head = &kprobe_table[i]; | |
1234 | hlist_for_each_entry_rcu(p, node, head, hlist) | |
1235 | arch_arm_kprobe(p); | |
1236 | } | |
1237 | ||
1238 | kprobe_enabled = true; | |
1239 | printk(KERN_INFO "Kprobes globally enabled\n"); | |
1240 | ||
1241 | already_enabled: | |
1242 | mutex_unlock(&kprobe_mutex); | |
1243 | return; | |
1244 | } | |
1245 | ||
1246 | static void __kprobes disable_all_kprobes(void) | |
1247 | { | |
1248 | struct hlist_head *head; | |
1249 | struct hlist_node *node; | |
1250 | struct kprobe *p; | |
1251 | unsigned int i; | |
1252 | ||
1253 | mutex_lock(&kprobe_mutex); | |
1254 | ||
1255 | /* If kprobes are already disabled, just return */ | |
1256 | if (!kprobe_enabled) | |
1257 | goto already_disabled; | |
1258 | ||
1259 | kprobe_enabled = false; | |
1260 | printk(KERN_INFO "Kprobes globally disabled\n"); | |
1261 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { | |
1262 | head = &kprobe_table[i]; | |
1263 | hlist_for_each_entry_rcu(p, node, head, hlist) { | |
1264 | if (!arch_trampoline_kprobe(p)) | |
1265 | arch_disarm_kprobe(p); | |
1266 | } | |
1267 | } | |
1268 | ||
1269 | mutex_unlock(&kprobe_mutex); | |
1270 | /* Allow all currently running kprobes to complete */ | |
1271 | synchronize_sched(); | |
74a0b576 | 1272 | return; |
bf8f6e5b AM |
1273 | |
1274 | already_disabled: | |
1275 | mutex_unlock(&kprobe_mutex); | |
1276 | return; | |
1277 | } | |
1278 | ||
1279 | /* | |
1280 | * XXX: The debugfs bool file interface doesn't allow for callbacks | |
1281 | * when the bool state is switched. We can reuse that facility when | |
1282 | * available | |
1283 | */ | |
1284 | static ssize_t read_enabled_file_bool(struct file *file, | |
1285 | char __user *user_buf, size_t count, loff_t *ppos) | |
1286 | { | |
1287 | char buf[3]; | |
1288 | ||
1289 | if (kprobe_enabled) | |
1290 | buf[0] = '1'; | |
1291 | else | |
1292 | buf[0] = '0'; | |
1293 | buf[1] = '\n'; | |
1294 | buf[2] = 0x00; | |
1295 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); | |
1296 | } | |
1297 | ||
1298 | static ssize_t write_enabled_file_bool(struct file *file, | |
1299 | const char __user *user_buf, size_t count, loff_t *ppos) | |
1300 | { | |
1301 | char buf[32]; | |
1302 | int buf_size; | |
1303 | ||
1304 | buf_size = min(count, (sizeof(buf)-1)); | |
1305 | if (copy_from_user(buf, user_buf, buf_size)) | |
1306 | return -EFAULT; | |
1307 | ||
1308 | switch (buf[0]) { | |
1309 | case 'y': | |
1310 | case 'Y': | |
1311 | case '1': | |
1312 | enable_all_kprobes(); | |
1313 | break; | |
1314 | case 'n': | |
1315 | case 'N': | |
1316 | case '0': | |
1317 | disable_all_kprobes(); | |
1318 | break; | |
1319 | } | |
1320 | ||
1321 | return count; | |
1322 | } | |
1323 | ||
1324 | static struct file_operations fops_kp = { | |
1325 | .read = read_enabled_file_bool, | |
1326 | .write = write_enabled_file_bool, | |
1327 | }; | |
1328 | ||
346fd59b SD |
1329 | static int __kprobes debugfs_kprobe_init(void) |
1330 | { | |
1331 | struct dentry *dir, *file; | |
bf8f6e5b | 1332 | unsigned int value = 1; |
346fd59b SD |
1333 | |
1334 | dir = debugfs_create_dir("kprobes", NULL); | |
1335 | if (!dir) | |
1336 | return -ENOMEM; | |
1337 | ||
e3869792 | 1338 | file = debugfs_create_file("list", 0444, dir, NULL, |
346fd59b SD |
1339 | &debugfs_kprobes_operations); |
1340 | if (!file) { | |
1341 | debugfs_remove(dir); | |
1342 | return -ENOMEM; | |
1343 | } | |
1344 | ||
bf8f6e5b AM |
1345 | file = debugfs_create_file("enabled", 0600, dir, |
1346 | &value, &fops_kp); | |
1347 | if (!file) { | |
1348 | debugfs_remove(dir); | |
1349 | return -ENOMEM; | |
1350 | } | |
1351 | ||
346fd59b SD |
1352 | return 0; |
1353 | } | |
1354 | ||
1355 | late_initcall(debugfs_kprobe_init); | |
1356 | #endif /* CONFIG_DEBUG_FS */ | |
1357 | ||
1358 | module_init(init_kprobes); | |
1da177e4 LT |
1359 | |
1360 | EXPORT_SYMBOL_GPL(register_kprobe); | |
1361 | EXPORT_SYMBOL_GPL(unregister_kprobe); | |
9861668f MH |
1362 | EXPORT_SYMBOL_GPL(register_kprobes); |
1363 | EXPORT_SYMBOL_GPL(unregister_kprobes); | |
1da177e4 LT |
1364 | EXPORT_SYMBOL_GPL(register_jprobe); |
1365 | EXPORT_SYMBOL_GPL(unregister_jprobe); | |
26b31c19 MH |
1366 | EXPORT_SYMBOL_GPL(register_jprobes); |
1367 | EXPORT_SYMBOL_GPL(unregister_jprobes); | |
1da177e4 | 1368 | EXPORT_SYMBOL_GPL(jprobe_return); |
b94cce92 HN |
1369 | EXPORT_SYMBOL_GPL(register_kretprobe); |
1370 | EXPORT_SYMBOL_GPL(unregister_kretprobe); | |
4a296e07 MH |
1371 | EXPORT_SYMBOL_GPL(register_kretprobes); |
1372 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |