Commit | Line | Data |
---|---|---|
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 | ||
1da177e4 | 65 | static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; |
b94cce92 | 66 | static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; |
1da177e4 | 67 | |
bf8f6e5b AM |
68 | /* NOTE: change this value only with kprobe_mutex held */ |
69 | static bool kprobe_enabled; | |
70 | ||
7a7d1cf9 | 71 | DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */ |
3516a460 | 72 | DEFINE_SPINLOCK(kretprobe_lock); /* Protects kretprobe_inst_table */ |
e6584523 | 73 | static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; |
1da177e4 | 74 | |
3d8d996e SD |
75 | /* |
76 | * Normally, functions that we'd want to prohibit kprobes in, are marked | |
77 | * __kprobes. But, there are cases where such functions already belong to | |
78 | * a different section (__sched for preempt_schedule) | |
79 | * | |
80 | * For such cases, we now have a blacklist | |
81 | */ | |
544304b2 | 82 | static struct kprobe_blackpoint kprobe_blacklist[] = { |
3d8d996e SD |
83 | {"preempt_schedule",}, |
84 | {NULL} /* Terminator */ | |
85 | }; | |
86 | ||
2d14e39d | 87 | #ifdef __ARCH_WANT_KPROBES_INSN_SLOT |
9ec4b1f3 AM |
88 | /* |
89 | * kprobe->ainsn.insn points to the copy of the instruction to be | |
90 | * single-stepped. x86_64, POWER4 and above have no-exec support and | |
91 | * stepping on the instruction on a vmalloced/kmalloced/data page | |
92 | * is a recipe for disaster | |
93 | */ | |
94 | #define INSNS_PER_PAGE (PAGE_SIZE/(MAX_INSN_SIZE * sizeof(kprobe_opcode_t))) | |
95 | ||
96 | struct kprobe_insn_page { | |
97 | struct hlist_node hlist; | |
98 | kprobe_opcode_t *insns; /* Page of instruction slots */ | |
99 | char slot_used[INSNS_PER_PAGE]; | |
100 | int nused; | |
b4c6c34a | 101 | int ngarbage; |
9ec4b1f3 AM |
102 | }; |
103 | ||
ab40c5c6 MH |
104 | enum kprobe_slot_state { |
105 | SLOT_CLEAN = 0, | |
106 | SLOT_DIRTY = 1, | |
107 | SLOT_USED = 2, | |
108 | }; | |
109 | ||
9ec4b1f3 | 110 | static struct hlist_head kprobe_insn_pages; |
b4c6c34a MH |
111 | static int kprobe_garbage_slots; |
112 | static int collect_garbage_slots(void); | |
113 | ||
114 | static int __kprobes check_safety(void) | |
115 | { | |
116 | int ret = 0; | |
117 | #if defined(CONFIG_PREEMPT) && defined(CONFIG_PM) | |
118 | ret = freeze_processes(); | |
119 | if (ret == 0) { | |
120 | struct task_struct *p, *q; | |
121 | do_each_thread(p, q) { | |
122 | if (p != current && p->state == TASK_RUNNING && | |
123 | p->pid != 0) { | |
124 | printk("Check failed: %s is running\n",p->comm); | |
125 | ret = -1; | |
126 | goto loop_end; | |
127 | } | |
128 | } while_each_thread(p, q); | |
129 | } | |
130 | loop_end: | |
131 | thaw_processes(); | |
132 | #else | |
133 | synchronize_sched(); | |
134 | #endif | |
135 | return ret; | |
136 | } | |
9ec4b1f3 AM |
137 | |
138 | /** | |
139 | * get_insn_slot() - Find a slot on an executable page for an instruction. | |
140 | * We allocate an executable page if there's no room on existing ones. | |
141 | */ | |
d0aaff97 | 142 | kprobe_opcode_t __kprobes *get_insn_slot(void) |
9ec4b1f3 AM |
143 | { |
144 | struct kprobe_insn_page *kip; | |
145 | struct hlist_node *pos; | |
146 | ||
6f716acd | 147 | retry: |
b0bb5016 | 148 | hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) { |
9ec4b1f3 AM |
149 | if (kip->nused < INSNS_PER_PAGE) { |
150 | int i; | |
151 | for (i = 0; i < INSNS_PER_PAGE; i++) { | |
ab40c5c6 MH |
152 | if (kip->slot_used[i] == SLOT_CLEAN) { |
153 | kip->slot_used[i] = SLOT_USED; | |
9ec4b1f3 AM |
154 | kip->nused++; |
155 | return kip->insns + (i * MAX_INSN_SIZE); | |
156 | } | |
157 | } | |
158 | /* Surprise! No unused slots. Fix kip->nused. */ | |
159 | kip->nused = INSNS_PER_PAGE; | |
160 | } | |
161 | } | |
162 | ||
b4c6c34a MH |
163 | /* If there are any garbage slots, collect it and try again. */ |
164 | if (kprobe_garbage_slots && collect_garbage_slots() == 0) { | |
165 | goto retry; | |
166 | } | |
167 | /* All out of space. Need to allocate a new page. Use slot 0. */ | |
9ec4b1f3 | 168 | kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL); |
6f716acd | 169 | if (!kip) |
9ec4b1f3 | 170 | return NULL; |
9ec4b1f3 AM |
171 | |
172 | /* | |
173 | * Use module_alloc so this page is within +/- 2GB of where the | |
174 | * kernel image and loaded module images reside. This is required | |
175 | * so x86_64 can correctly handle the %rip-relative fixups. | |
176 | */ | |
177 | kip->insns = module_alloc(PAGE_SIZE); | |
178 | if (!kip->insns) { | |
179 | kfree(kip); | |
180 | return NULL; | |
181 | } | |
182 | INIT_HLIST_NODE(&kip->hlist); | |
183 | hlist_add_head(&kip->hlist, &kprobe_insn_pages); | |
ab40c5c6 MH |
184 | memset(kip->slot_used, SLOT_CLEAN, INSNS_PER_PAGE); |
185 | kip->slot_used[0] = SLOT_USED; | |
9ec4b1f3 | 186 | kip->nused = 1; |
b4c6c34a | 187 | kip->ngarbage = 0; |
9ec4b1f3 AM |
188 | return kip->insns; |
189 | } | |
190 | ||
b4c6c34a MH |
191 | /* Return 1 if all garbages are collected, otherwise 0. */ |
192 | static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx) | |
193 | { | |
ab40c5c6 | 194 | kip->slot_used[idx] = SLOT_CLEAN; |
b4c6c34a MH |
195 | kip->nused--; |
196 | if (kip->nused == 0) { | |
197 | /* | |
198 | * Page is no longer in use. Free it unless | |
199 | * it's the last one. We keep the last one | |
200 | * so as not to have to set it up again the | |
201 | * next time somebody inserts a probe. | |
202 | */ | |
203 | hlist_del(&kip->hlist); | |
204 | if (hlist_empty(&kprobe_insn_pages)) { | |
205 | INIT_HLIST_NODE(&kip->hlist); | |
206 | hlist_add_head(&kip->hlist, | |
207 | &kprobe_insn_pages); | |
208 | } else { | |
209 | module_free(NULL, kip->insns); | |
210 | kfree(kip); | |
211 | } | |
212 | return 1; | |
213 | } | |
214 | return 0; | |
215 | } | |
216 | ||
217 | static int __kprobes collect_garbage_slots(void) | |
218 | { | |
219 | struct kprobe_insn_page *kip; | |
220 | struct hlist_node *pos, *next; | |
221 | ||
222 | /* Ensure no-one is preepmted on the garbages */ | |
223 | if (check_safety() != 0) | |
224 | return -EAGAIN; | |
225 | ||
b0bb5016 | 226 | hlist_for_each_entry_safe(kip, pos, next, &kprobe_insn_pages, hlist) { |
b4c6c34a | 227 | int i; |
b4c6c34a MH |
228 | if (kip->ngarbage == 0) |
229 | continue; | |
230 | kip->ngarbage = 0; /* we will collect all garbages */ | |
231 | for (i = 0; i < INSNS_PER_PAGE; i++) { | |
ab40c5c6 | 232 | if (kip->slot_used[i] == SLOT_DIRTY && |
b4c6c34a MH |
233 | collect_one_slot(kip, i)) |
234 | break; | |
235 | } | |
236 | } | |
237 | kprobe_garbage_slots = 0; | |
238 | return 0; | |
239 | } | |
240 | ||
241 | void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty) | |
9ec4b1f3 AM |
242 | { |
243 | struct kprobe_insn_page *kip; | |
244 | struct hlist_node *pos; | |
245 | ||
b0bb5016 | 246 | hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) { |
9ec4b1f3 AM |
247 | if (kip->insns <= slot && |
248 | slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) { | |
249 | int i = (slot - kip->insns) / MAX_INSN_SIZE; | |
b4c6c34a | 250 | if (dirty) { |
ab40c5c6 | 251 | kip->slot_used[i] = SLOT_DIRTY; |
b4c6c34a MH |
252 | kip->ngarbage++; |
253 | } else { | |
254 | collect_one_slot(kip, i); | |
9ec4b1f3 | 255 | } |
b4c6c34a | 256 | break; |
9ec4b1f3 AM |
257 | } |
258 | } | |
6f716acd CH |
259 | |
260 | if (dirty && ++kprobe_garbage_slots > INSNS_PER_PAGE) | |
b4c6c34a | 261 | collect_garbage_slots(); |
9ec4b1f3 | 262 | } |
2d14e39d | 263 | #endif |
9ec4b1f3 | 264 | |
e6584523 AM |
265 | /* We have preemption disabled.. so it is safe to use __ versions */ |
266 | static inline void set_kprobe_instance(struct kprobe *kp) | |
267 | { | |
268 | __get_cpu_var(kprobe_instance) = kp; | |
269 | } | |
270 | ||
271 | static inline void reset_kprobe_instance(void) | |
272 | { | |
273 | __get_cpu_var(kprobe_instance) = NULL; | |
274 | } | |
275 | ||
3516a460 AM |
276 | /* |
277 | * This routine is called either: | |
49a2a1b8 | 278 | * - under the kprobe_mutex - during kprobe_[un]register() |
3516a460 | 279 | * OR |
d217d545 | 280 | * - with preemption disabled - from arch/xxx/kernel/kprobes.c |
3516a460 | 281 | */ |
d0aaff97 | 282 | struct kprobe __kprobes *get_kprobe(void *addr) |
1da177e4 LT |
283 | { |
284 | struct hlist_head *head; | |
285 | struct hlist_node *node; | |
3516a460 | 286 | struct kprobe *p; |
1da177e4 LT |
287 | |
288 | head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; | |
3516a460 | 289 | hlist_for_each_entry_rcu(p, node, head, hlist) { |
1da177e4 LT |
290 | if (p->addr == addr) |
291 | return p; | |
292 | } | |
293 | return NULL; | |
294 | } | |
295 | ||
64f562c6 AM |
296 | /* |
297 | * Aggregate handlers for multiple kprobes support - these handlers | |
298 | * take care of invoking the individual kprobe handlers on p->list | |
299 | */ | |
d0aaff97 | 300 | static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
64f562c6 AM |
301 | { |
302 | struct kprobe *kp; | |
303 | ||
3516a460 | 304 | list_for_each_entry_rcu(kp, &p->list, list) { |
64f562c6 | 305 | if (kp->pre_handler) { |
e6584523 | 306 | set_kprobe_instance(kp); |
8b0914ea PP |
307 | if (kp->pre_handler(kp, regs)) |
308 | return 1; | |
64f562c6 | 309 | } |
e6584523 | 310 | reset_kprobe_instance(); |
64f562c6 AM |
311 | } |
312 | return 0; | |
313 | } | |
314 | ||
d0aaff97 PP |
315 | static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
316 | unsigned long flags) | |
64f562c6 AM |
317 | { |
318 | struct kprobe *kp; | |
319 | ||
3516a460 | 320 | list_for_each_entry_rcu(kp, &p->list, list) { |
64f562c6 | 321 | if (kp->post_handler) { |
e6584523 | 322 | set_kprobe_instance(kp); |
64f562c6 | 323 | kp->post_handler(kp, regs, flags); |
e6584523 | 324 | reset_kprobe_instance(); |
64f562c6 AM |
325 | } |
326 | } | |
64f562c6 AM |
327 | } |
328 | ||
d0aaff97 PP |
329 | static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, |
330 | int trapnr) | |
64f562c6 | 331 | { |
e6584523 AM |
332 | struct kprobe *cur = __get_cpu_var(kprobe_instance); |
333 | ||
64f562c6 AM |
334 | /* |
335 | * if we faulted "during" the execution of a user specified | |
336 | * probe handler, invoke just that probe's fault handler | |
337 | */ | |
e6584523 AM |
338 | if (cur && cur->fault_handler) { |
339 | if (cur->fault_handler(cur, regs, trapnr)) | |
64f562c6 AM |
340 | return 1; |
341 | } | |
342 | return 0; | |
343 | } | |
344 | ||
d0aaff97 | 345 | static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs) |
8b0914ea | 346 | { |
e6584523 AM |
347 | struct kprobe *cur = __get_cpu_var(kprobe_instance); |
348 | int ret = 0; | |
349 | ||
350 | if (cur && cur->break_handler) { | |
351 | if (cur->break_handler(cur, regs)) | |
352 | ret = 1; | |
8b0914ea | 353 | } |
e6584523 AM |
354 | reset_kprobe_instance(); |
355 | return ret; | |
8b0914ea PP |
356 | } |
357 | ||
bf8d5c52 KA |
358 | /* Walks the list and increments nmissed count for multiprobe case */ |
359 | void __kprobes kprobes_inc_nmissed_count(struct kprobe *p) | |
360 | { | |
361 | struct kprobe *kp; | |
362 | if (p->pre_handler != aggr_pre_handler) { | |
363 | p->nmissed++; | |
364 | } else { | |
365 | list_for_each_entry_rcu(kp, &p->list, list) | |
366 | kp->nmissed++; | |
367 | } | |
368 | return; | |
369 | } | |
370 | ||
3516a460 | 371 | /* Called with kretprobe_lock held */ |
99219a3f | 372 | void __kprobes recycle_rp_inst(struct kretprobe_instance *ri, |
373 | struct hlist_head *head) | |
b94cce92 HN |
374 | { |
375 | /* remove rp inst off the rprobe_inst_table */ | |
376 | hlist_del(&ri->hlist); | |
377 | if (ri->rp) { | |
378 | /* remove rp inst off the used list */ | |
379 | hlist_del(&ri->uflist); | |
380 | /* put rp inst back onto the free list */ | |
381 | INIT_HLIST_NODE(&ri->uflist); | |
382 | hlist_add_head(&ri->uflist, &ri->rp->free_instances); | |
383 | } else | |
384 | /* Unregistering */ | |
99219a3f | 385 | hlist_add_head(&ri->hlist, head); |
b94cce92 HN |
386 | } |
387 | ||
d0aaff97 | 388 | struct hlist_head __kprobes *kretprobe_inst_table_head(struct task_struct *tsk) |
b94cce92 HN |
389 | { |
390 | return &kretprobe_inst_table[hash_ptr(tsk, KPROBE_HASH_BITS)]; | |
391 | } | |
392 | ||
b94cce92 | 393 | /* |
c6fd91f0 | 394 | * This function is called from finish_task_switch when task tk becomes dead, |
395 | * so that we can recycle any function-return probe instances associated | |
396 | * with this task. These left over instances represent probed functions | |
397 | * that have been called but will never return. | |
b94cce92 | 398 | */ |
d0aaff97 | 399 | void __kprobes kprobe_flush_task(struct task_struct *tk) |
b94cce92 | 400 | { |
62c27be0 | 401 | struct kretprobe_instance *ri; |
99219a3f | 402 | struct hlist_head *head, empty_rp; |
802eae7c | 403 | struct hlist_node *node, *tmp; |
0aa55e4d | 404 | unsigned long flags = 0; |
802eae7c | 405 | |
99219a3f | 406 | INIT_HLIST_HEAD(&empty_rp); |
3516a460 | 407 | spin_lock_irqsave(&kretprobe_lock, flags); |
62c27be0 | 408 | head = kretprobe_inst_table_head(tk); |
409 | hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { | |
410 | if (ri->task == tk) | |
99219a3f | 411 | recycle_rp_inst(ri, &empty_rp); |
62c27be0 | 412 | } |
3516a460 | 413 | spin_unlock_irqrestore(&kretprobe_lock, flags); |
99219a3f | 414 | |
415 | hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { | |
416 | hlist_del(&ri->hlist); | |
417 | kfree(ri); | |
418 | } | |
b94cce92 HN |
419 | } |
420 | ||
b94cce92 HN |
421 | static inline void free_rp_inst(struct kretprobe *rp) |
422 | { | |
423 | struct kretprobe_instance *ri; | |
4c4308cb CH |
424 | struct hlist_node *pos, *next; |
425 | ||
426 | hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, uflist) { | |
b94cce92 HN |
427 | hlist_del(&ri->uflist); |
428 | kfree(ri); | |
429 | } | |
430 | } | |
431 | ||
4a296e07 MH |
432 | static void __kprobes cleanup_rp_inst(struct kretprobe *rp) |
433 | { | |
434 | unsigned long flags; | |
435 | struct kretprobe_instance *ri; | |
436 | struct hlist_node *pos, *next; | |
437 | /* No race here */ | |
438 | spin_lock_irqsave(&kretprobe_lock, flags); | |
439 | hlist_for_each_entry_safe(ri, pos, next, &rp->used_instances, uflist) { | |
440 | ri->rp = NULL; | |
441 | hlist_del(&ri->uflist); | |
442 | } | |
443 | spin_unlock_irqrestore(&kretprobe_lock, flags); | |
444 | free_rp_inst(rp); | |
445 | } | |
446 | ||
8b0914ea PP |
447 | /* |
448 | * Keep all fields in the kprobe consistent | |
449 | */ | |
450 | static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p) | |
451 | { | |
452 | memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t)); | |
453 | memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn)); | |
454 | } | |
455 | ||
456 | /* | |
457 | * Add the new probe to old_p->list. Fail if this is the | |
458 | * second jprobe at the address - two jprobes can't coexist | |
459 | */ | |
d0aaff97 | 460 | static int __kprobes add_new_kprobe(struct kprobe *old_p, struct kprobe *p) |
8b0914ea | 461 | { |
8b0914ea | 462 | if (p->break_handler) { |
36721656 | 463 | if (old_p->break_handler) |
464 | return -EEXIST; | |
3516a460 | 465 | list_add_tail_rcu(&p->list, &old_p->list); |
36721656 | 466 | old_p->break_handler = aggr_break_handler; |
8b0914ea | 467 | } else |
3516a460 | 468 | list_add_rcu(&p->list, &old_p->list); |
36721656 | 469 | if (p->post_handler && !old_p->post_handler) |
470 | old_p->post_handler = aggr_post_handler; | |
8b0914ea PP |
471 | return 0; |
472 | } | |
473 | ||
64f562c6 AM |
474 | /* |
475 | * Fill in the required fields of the "manager kprobe". Replace the | |
476 | * earlier kprobe in the hlist with the manager kprobe | |
477 | */ | |
478 | static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p) | |
479 | { | |
8b0914ea | 480 | copy_kprobe(p, ap); |
a9ad965e | 481 | flush_insn_slot(ap); |
64f562c6 | 482 | ap->addr = p->addr; |
64f562c6 | 483 | ap->pre_handler = aggr_pre_handler; |
64f562c6 | 484 | ap->fault_handler = aggr_fault_handler; |
36721656 | 485 | if (p->post_handler) |
486 | ap->post_handler = aggr_post_handler; | |
487 | if (p->break_handler) | |
488 | ap->break_handler = aggr_break_handler; | |
64f562c6 AM |
489 | |
490 | INIT_LIST_HEAD(&ap->list); | |
3516a460 | 491 | list_add_rcu(&p->list, &ap->list); |
64f562c6 | 492 | |
adad0f33 | 493 | hlist_replace_rcu(&p->hlist, &ap->hlist); |
64f562c6 AM |
494 | } |
495 | ||
496 | /* | |
497 | * This is the second or subsequent kprobe at the address - handle | |
498 | * the intricacies | |
64f562c6 | 499 | */ |
d0aaff97 PP |
500 | static int __kprobes register_aggr_kprobe(struct kprobe *old_p, |
501 | struct kprobe *p) | |
64f562c6 AM |
502 | { |
503 | int ret = 0; | |
504 | struct kprobe *ap; | |
505 | ||
8b0914ea PP |
506 | if (old_p->pre_handler == aggr_pre_handler) { |
507 | copy_kprobe(old_p, p); | |
508 | ret = add_new_kprobe(old_p, p); | |
64f562c6 | 509 | } else { |
a0d50069 | 510 | ap = kzalloc(sizeof(struct kprobe), GFP_KERNEL); |
64f562c6 AM |
511 | if (!ap) |
512 | return -ENOMEM; | |
513 | add_aggr_kprobe(ap, old_p); | |
8b0914ea PP |
514 | copy_kprobe(ap, p); |
515 | ret = add_new_kprobe(ap, p); | |
64f562c6 AM |
516 | } |
517 | return ret; | |
518 | } | |
519 | ||
d0aaff97 PP |
520 | static int __kprobes in_kprobes_functions(unsigned long addr) |
521 | { | |
3d8d996e SD |
522 | struct kprobe_blackpoint *kb; |
523 | ||
6f716acd CH |
524 | if (addr >= (unsigned long)__kprobes_text_start && |
525 | addr < (unsigned long)__kprobes_text_end) | |
d0aaff97 | 526 | return -EINVAL; |
3d8d996e SD |
527 | /* |
528 | * If there exists a kprobe_blacklist, verify and | |
529 | * fail any probe registration in the prohibited area | |
530 | */ | |
531 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { | |
532 | if (kb->start_addr) { | |
533 | if (addr >= kb->start_addr && | |
534 | addr < (kb->start_addr + kb->range)) | |
535 | return -EINVAL; | |
536 | } | |
537 | } | |
d0aaff97 PP |
538 | return 0; |
539 | } | |
540 | ||
b2a5cd69 MH |
541 | /* |
542 | * If we have a symbol_name argument, look it up and add the offset field | |
543 | * to it. This way, we can specify a relative address to a symbol. | |
544 | */ | |
545 | static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p) | |
546 | { | |
547 | kprobe_opcode_t *addr = p->addr; | |
548 | if (p->symbol_name) { | |
549 | if (addr) | |
550 | return NULL; | |
551 | kprobe_lookup_name(p->symbol_name, addr); | |
552 | } | |
553 | ||
554 | if (!addr) | |
555 | return NULL; | |
556 | return (kprobe_opcode_t *)(((char *)addr) + p->offset); | |
557 | } | |
558 | ||
df019b1d KA |
559 | static int __kprobes __register_kprobe(struct kprobe *p, |
560 | unsigned long called_from) | |
1da177e4 LT |
561 | { |
562 | int ret = 0; | |
64f562c6 | 563 | struct kprobe *old_p; |
df019b1d | 564 | struct module *probed_mod; |
b2a5cd69 | 565 | kprobe_opcode_t *addr; |
b3e55c72 | 566 | |
b2a5cd69 MH |
567 | addr = kprobe_addr(p); |
568 | if (!addr) | |
3a872d89 | 569 | return -EINVAL; |
b2a5cd69 | 570 | p->addr = addr; |
3a872d89 | 571 | |
6f716acd CH |
572 | if (!kernel_text_address((unsigned long) p->addr) || |
573 | in_kprobes_functions((unsigned long) p->addr)) | |
b3e55c72 MB |
574 | return -EINVAL; |
575 | ||
df019b1d | 576 | p->mod_refcounted = 0; |
6f716acd CH |
577 | |
578 | /* | |
579 | * Check if are we probing a module. | |
580 | */ | |
581 | probed_mod = module_text_address((unsigned long) p->addr); | |
582 | if (probed_mod) { | |
df019b1d | 583 | struct module *calling_mod = module_text_address(called_from); |
6f716acd CH |
584 | /* |
585 | * We must allow modules to probe themself and in this case | |
586 | * avoid incrementing the module refcount, so as to allow | |
587 | * unloading of self probing modules. | |
df019b1d | 588 | */ |
6f716acd | 589 | if (calling_mod && calling_mod != probed_mod) { |
df019b1d KA |
590 | if (unlikely(!try_module_get(probed_mod))) |
591 | return -EINVAL; | |
592 | p->mod_refcounted = 1; | |
593 | } else | |
594 | probed_mod = NULL; | |
595 | } | |
1da177e4 | 596 | |
3516a460 | 597 | p->nmissed = 0; |
9861668f | 598 | INIT_LIST_HEAD(&p->list); |
7a7d1cf9 | 599 | mutex_lock(&kprobe_mutex); |
64f562c6 AM |
600 | old_p = get_kprobe(p->addr); |
601 | if (old_p) { | |
602 | ret = register_aggr_kprobe(old_p, p); | |
1da177e4 LT |
603 | goto out; |
604 | } | |
1da177e4 | 605 | |
6f716acd CH |
606 | ret = arch_prepare_kprobe(p); |
607 | if (ret) | |
49a2a1b8 AK |
608 | goto out; |
609 | ||
64f562c6 | 610 | INIT_HLIST_NODE(&p->hlist); |
3516a460 | 611 | hlist_add_head_rcu(&p->hlist, |
1da177e4 LT |
612 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); |
613 | ||
74a0b576 | 614 | if (kprobe_enabled) |
bf8f6e5b | 615 | arch_arm_kprobe(p); |
74a0b576 | 616 | |
1da177e4 | 617 | out: |
7a7d1cf9 | 618 | mutex_unlock(&kprobe_mutex); |
49a2a1b8 | 619 | |
df019b1d KA |
620 | if (ret && probed_mod) |
621 | module_put(probed_mod); | |
1da177e4 LT |
622 | return ret; |
623 | } | |
624 | ||
9861668f MH |
625 | /* |
626 | * Unregister a kprobe without a scheduler synchronization. | |
627 | */ | |
628 | static int __kprobes __unregister_kprobe_top(struct kprobe *p) | |
1da177e4 | 629 | { |
f709b122 | 630 | struct kprobe *old_p, *list_p; |
64f562c6 | 631 | |
64f562c6 | 632 | old_p = get_kprobe(p->addr); |
9861668f MH |
633 | if (unlikely(!old_p)) |
634 | return -EINVAL; | |
635 | ||
f709b122 KA |
636 | if (p != old_p) { |
637 | list_for_each_entry_rcu(list_p, &old_p->list, list) | |
638 | if (list_p == p) | |
639 | /* kprobe p is a valid probe */ | |
640 | goto valid_p; | |
9861668f | 641 | return -EINVAL; |
f709b122 KA |
642 | } |
643 | valid_p: | |
6f716acd CH |
644 | if (old_p == p || |
645 | (old_p->pre_handler == aggr_pre_handler && | |
9861668f | 646 | list_is_singular(&old_p->list))) { |
bf8f6e5b AM |
647 | /* |
648 | * Only probe on the hash list. Disarm only if kprobes are | |
649 | * enabled - otherwise, the breakpoint would already have | |
650 | * been removed. We save on flushing icache. | |
651 | */ | |
652 | if (kprobe_enabled) | |
653 | arch_disarm_kprobe(p); | |
49a2a1b8 | 654 | hlist_del_rcu(&old_p->hlist); |
49a2a1b8 | 655 | } else { |
9861668f MH |
656 | if (p->break_handler) |
657 | old_p->break_handler = NULL; | |
658 | if (p->post_handler) { | |
659 | list_for_each_entry_rcu(list_p, &old_p->list, list) { | |
660 | if ((list_p != p) && (list_p->post_handler)) | |
661 | goto noclean; | |
662 | } | |
663 | old_p->post_handler = NULL; | |
664 | } | |
665 | noclean: | |
49a2a1b8 | 666 | list_del_rcu(&p->list); |
49a2a1b8 | 667 | } |
9861668f MH |
668 | return 0; |
669 | } | |
3516a460 | 670 | |
9861668f MH |
671 | static void __kprobes __unregister_kprobe_bottom(struct kprobe *p) |
672 | { | |
673 | struct module *mod; | |
674 | struct kprobe *old_p; | |
b3e55c72 | 675 | |
6f716acd CH |
676 | if (p->mod_refcounted) { |
677 | mod = module_text_address((unsigned long)p->addr); | |
678 | if (mod) | |
679 | module_put(mod); | |
680 | } | |
b3e55c72 | 681 | |
9861668f MH |
682 | if (list_empty(&p->list) || list_is_singular(&p->list)) { |
683 | if (!list_empty(&p->list)) { | |
684 | /* "p" is the last child of an aggr_kprobe */ | |
685 | old_p = list_entry(p->list.next, struct kprobe, list); | |
686 | list_del(&p->list); | |
3516a460 | 687 | kfree(old_p); |
49a2a1b8 | 688 | } |
0498b635 | 689 | arch_remove_kprobe(p); |
9861668f MH |
690 | } |
691 | } | |
692 | ||
693 | static int __register_kprobes(struct kprobe **kps, int num, | |
694 | unsigned long called_from) | |
695 | { | |
696 | int i, ret = 0; | |
697 | ||
698 | if (num <= 0) | |
699 | return -EINVAL; | |
700 | for (i = 0; i < num; i++) { | |
701 | ret = __register_kprobe(kps[i], called_from); | |
67dddaad MH |
702 | if (ret < 0) { |
703 | if (i > 0) | |
704 | unregister_kprobes(kps, i); | |
9861668f | 705 | break; |
36721656 | 706 | } |
49a2a1b8 | 707 | } |
9861668f MH |
708 | return ret; |
709 | } | |
710 | ||
711 | /* | |
712 | * Registration and unregistration functions for kprobe. | |
713 | */ | |
714 | int __kprobes register_kprobe(struct kprobe *p) | |
715 | { | |
716 | return __register_kprobes(&p, 1, | |
717 | (unsigned long)__builtin_return_address(0)); | |
718 | } | |
719 | ||
720 | void __kprobes unregister_kprobe(struct kprobe *p) | |
721 | { | |
722 | unregister_kprobes(&p, 1); | |
723 | } | |
724 | ||
725 | int __kprobes register_kprobes(struct kprobe **kps, int num) | |
726 | { | |
727 | return __register_kprobes(kps, num, | |
728 | (unsigned long)__builtin_return_address(0)); | |
729 | } | |
730 | ||
731 | void __kprobes unregister_kprobes(struct kprobe **kps, int num) | |
732 | { | |
733 | int i; | |
734 | ||
735 | if (num <= 0) | |
736 | return; | |
737 | mutex_lock(&kprobe_mutex); | |
738 | for (i = 0; i < num; i++) | |
739 | if (__unregister_kprobe_top(kps[i]) < 0) | |
740 | kps[i]->addr = NULL; | |
741 | mutex_unlock(&kprobe_mutex); | |
742 | ||
743 | synchronize_sched(); | |
744 | for (i = 0; i < num; i++) | |
745 | if (kps[i]->addr) | |
746 | __unregister_kprobe_bottom(kps[i]); | |
1da177e4 LT |
747 | } |
748 | ||
749 | static struct notifier_block kprobe_exceptions_nb = { | |
3d5631e0 AK |
750 | .notifier_call = kprobe_exceptions_notify, |
751 | .priority = 0x7fffffff /* we need to be notified first */ | |
752 | }; | |
753 | ||
3d7e3382 ME |
754 | unsigned long __weak arch_deref_entry_point(void *entry) |
755 | { | |
756 | return (unsigned long)entry; | |
757 | } | |
1da177e4 | 758 | |
26b31c19 MH |
759 | static int __register_jprobes(struct jprobe **jps, int num, |
760 | unsigned long called_from) | |
1da177e4 | 761 | { |
26b31c19 MH |
762 | struct jprobe *jp; |
763 | int ret = 0, i; | |
3d7e3382 | 764 | |
26b31c19 | 765 | if (num <= 0) |
3d7e3382 | 766 | return -EINVAL; |
26b31c19 MH |
767 | for (i = 0; i < num; i++) { |
768 | unsigned long addr; | |
769 | jp = jps[i]; | |
770 | addr = arch_deref_entry_point(jp->entry); | |
771 | ||
772 | if (!kernel_text_address(addr)) | |
773 | ret = -EINVAL; | |
774 | else { | |
775 | /* Todo: Verify probepoint is a function entry point */ | |
776 | jp->kp.pre_handler = setjmp_pre_handler; | |
777 | jp->kp.break_handler = longjmp_break_handler; | |
778 | ret = __register_kprobe(&jp->kp, called_from); | |
779 | } | |
67dddaad MH |
780 | if (ret < 0) { |
781 | if (i > 0) | |
782 | unregister_jprobes(jps, i); | |
26b31c19 MH |
783 | break; |
784 | } | |
785 | } | |
786 | return ret; | |
787 | } | |
3d7e3382 | 788 | |
26b31c19 MH |
789 | int __kprobes register_jprobe(struct jprobe *jp) |
790 | { | |
791 | return __register_jprobes(&jp, 1, | |
df019b1d | 792 | (unsigned long)__builtin_return_address(0)); |
1da177e4 LT |
793 | } |
794 | ||
d0aaff97 | 795 | void __kprobes unregister_jprobe(struct jprobe *jp) |
1da177e4 | 796 | { |
26b31c19 MH |
797 | unregister_jprobes(&jp, 1); |
798 | } | |
799 | ||
800 | int __kprobes register_jprobes(struct jprobe **jps, int num) | |
801 | { | |
802 | return __register_jprobes(jps, num, | |
803 | (unsigned long)__builtin_return_address(0)); | |
804 | } | |
805 | ||
806 | void __kprobes unregister_jprobes(struct jprobe **jps, int num) | |
807 | { | |
808 | int i; | |
809 | ||
810 | if (num <= 0) | |
811 | return; | |
812 | mutex_lock(&kprobe_mutex); | |
813 | for (i = 0; i < num; i++) | |
814 | if (__unregister_kprobe_top(&jps[i]->kp) < 0) | |
815 | jps[i]->kp.addr = NULL; | |
816 | mutex_unlock(&kprobe_mutex); | |
817 | ||
818 | synchronize_sched(); | |
819 | for (i = 0; i < num; i++) { | |
820 | if (jps[i]->kp.addr) | |
821 | __unregister_kprobe_bottom(&jps[i]->kp); | |
822 | } | |
1da177e4 LT |
823 | } |
824 | ||
9edddaa2 | 825 | #ifdef CONFIG_KRETPROBES |
e65cefe8 AB |
826 | /* |
827 | * This kprobe pre_handler is registered with every kretprobe. When probe | |
828 | * hits it will set up the return probe. | |
829 | */ | |
830 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, | |
831 | struct pt_regs *regs) | |
832 | { | |
833 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); | |
834 | unsigned long flags = 0; | |
835 | ||
836 | /*TODO: consider to only swap the RA after the last pre_handler fired */ | |
837 | spin_lock_irqsave(&kretprobe_lock, flags); | |
4c4308cb CH |
838 | if (!hlist_empty(&rp->free_instances)) { |
839 | struct kretprobe_instance *ri; | |
840 | ||
841 | ri = hlist_entry(rp->free_instances.first, | |
842 | struct kretprobe_instance, uflist); | |
843 | ri->rp = rp; | |
844 | ri->task = current; | |
f47cd9b5 AS |
845 | |
846 | if (rp->entry_handler && rp->entry_handler(ri, regs)) { | |
847 | spin_unlock_irqrestore(&kretprobe_lock, flags); | |
848 | return 0; | |
849 | } | |
850 | ||
4c4308cb CH |
851 | arch_prepare_kretprobe(ri, regs); |
852 | ||
853 | /* XXX(hch): why is there no hlist_move_head? */ | |
854 | hlist_del(&ri->uflist); | |
855 | hlist_add_head(&ri->uflist, &ri->rp->used_instances); | |
856 | hlist_add_head(&ri->hlist, kretprobe_inst_table_head(ri->task)); | |
857 | } else | |
858 | rp->nmissed++; | |
e65cefe8 AB |
859 | spin_unlock_irqrestore(&kretprobe_lock, flags); |
860 | return 0; | |
861 | } | |
862 | ||
4a296e07 MH |
863 | static int __kprobes __register_kretprobe(struct kretprobe *rp, |
864 | unsigned long called_from) | |
b94cce92 HN |
865 | { |
866 | int ret = 0; | |
867 | struct kretprobe_instance *inst; | |
868 | int i; | |
b2a5cd69 | 869 | void *addr; |
f438d914 MH |
870 | |
871 | if (kretprobe_blacklist_size) { | |
b2a5cd69 MH |
872 | addr = kprobe_addr(&rp->kp); |
873 | if (!addr) | |
874 | return -EINVAL; | |
f438d914 MH |
875 | |
876 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
877 | if (kretprobe_blacklist[i].addr == addr) | |
878 | return -EINVAL; | |
879 | } | |
880 | } | |
b94cce92 HN |
881 | |
882 | rp->kp.pre_handler = pre_handler_kretprobe; | |
7522a842 AM |
883 | rp->kp.post_handler = NULL; |
884 | rp->kp.fault_handler = NULL; | |
885 | rp->kp.break_handler = NULL; | |
b94cce92 HN |
886 | |
887 | /* Pre-allocate memory for max kretprobe instances */ | |
888 | if (rp->maxactive <= 0) { | |
889 | #ifdef CONFIG_PREEMPT | |
890 | rp->maxactive = max(10, 2 * NR_CPUS); | |
891 | #else | |
892 | rp->maxactive = NR_CPUS; | |
893 | #endif | |
894 | } | |
895 | INIT_HLIST_HEAD(&rp->used_instances); | |
896 | INIT_HLIST_HEAD(&rp->free_instances); | |
897 | for (i = 0; i < rp->maxactive; i++) { | |
f47cd9b5 AS |
898 | inst = kmalloc(sizeof(struct kretprobe_instance) + |
899 | rp->data_size, GFP_KERNEL); | |
b94cce92 HN |
900 | if (inst == NULL) { |
901 | free_rp_inst(rp); | |
902 | return -ENOMEM; | |
903 | } | |
904 | INIT_HLIST_NODE(&inst->uflist); | |
905 | hlist_add_head(&inst->uflist, &rp->free_instances); | |
906 | } | |
907 | ||
908 | rp->nmissed = 0; | |
909 | /* Establish function entry probe point */ | |
4a296e07 MH |
910 | ret = __register_kprobe(&rp->kp, called_from); |
911 | if (ret != 0) | |
b94cce92 HN |
912 | free_rp_inst(rp); |
913 | return ret; | |
914 | } | |
915 | ||
4a296e07 MH |
916 | static int __register_kretprobes(struct kretprobe **rps, int num, |
917 | unsigned long called_from) | |
918 | { | |
919 | int ret = 0, i; | |
920 | ||
921 | if (num <= 0) | |
922 | return -EINVAL; | |
923 | for (i = 0; i < num; i++) { | |
924 | ret = __register_kretprobe(rps[i], called_from); | |
67dddaad MH |
925 | if (ret < 0) { |
926 | if (i > 0) | |
927 | unregister_kretprobes(rps, i); | |
4a296e07 MH |
928 | break; |
929 | } | |
930 | } | |
931 | return ret; | |
932 | } | |
933 | ||
934 | int __kprobes register_kretprobe(struct kretprobe *rp) | |
935 | { | |
936 | return __register_kretprobes(&rp, 1, | |
937 | (unsigned long)__builtin_return_address(0)); | |
938 | } | |
939 | ||
940 | void __kprobes unregister_kretprobe(struct kretprobe *rp) | |
941 | { | |
942 | unregister_kretprobes(&rp, 1); | |
943 | } | |
944 | ||
945 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) | |
946 | { | |
947 | return __register_kretprobes(rps, num, | |
948 | (unsigned long)__builtin_return_address(0)); | |
949 | } | |
950 | ||
951 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) | |
952 | { | |
953 | int i; | |
954 | ||
955 | if (num <= 0) | |
956 | return; | |
957 | mutex_lock(&kprobe_mutex); | |
958 | for (i = 0; i < num; i++) | |
959 | if (__unregister_kprobe_top(&rps[i]->kp) < 0) | |
960 | rps[i]->kp.addr = NULL; | |
961 | mutex_unlock(&kprobe_mutex); | |
962 | ||
963 | synchronize_sched(); | |
964 | for (i = 0; i < num; i++) { | |
965 | if (rps[i]->kp.addr) { | |
966 | __unregister_kprobe_bottom(&rps[i]->kp); | |
967 | cleanup_rp_inst(rps[i]); | |
968 | } | |
969 | } | |
970 | } | |
971 | ||
9edddaa2 | 972 | #else /* CONFIG_KRETPROBES */ |
d0aaff97 | 973 | int __kprobes register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
974 | { |
975 | return -ENOSYS; | |
976 | } | |
977 | ||
4a296e07 | 978 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) |
346fd59b | 979 | { |
4a296e07 | 980 | return -ENOSYS; |
346fd59b | 981 | } |
d0aaff97 | 982 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
b94cce92 | 983 | { |
4a296e07 | 984 | } |
b94cce92 | 985 | |
4a296e07 MH |
986 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) |
987 | { | |
988 | } | |
4c4308cb | 989 | |
4a296e07 MH |
990 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, |
991 | struct pt_regs *regs) | |
992 | { | |
993 | return 0; | |
b94cce92 HN |
994 | } |
995 | ||
4a296e07 MH |
996 | #endif /* CONFIG_KRETPROBES */ |
997 | ||
1da177e4 LT |
998 | static int __init init_kprobes(void) |
999 | { | |
1000 | int i, err = 0; | |
3d8d996e SD |
1001 | unsigned long offset = 0, size = 0; |
1002 | char *modname, namebuf[128]; | |
1003 | const char *symbol_name; | |
1004 | void *addr; | |
1005 | struct kprobe_blackpoint *kb; | |
1da177e4 LT |
1006 | |
1007 | /* FIXME allocate the probe table, currently defined statically */ | |
1008 | /* initialize all list heads */ | |
b94cce92 | 1009 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1da177e4 | 1010 | INIT_HLIST_HEAD(&kprobe_table[i]); |
b94cce92 HN |
1011 | INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
1012 | } | |
1da177e4 | 1013 | |
3d8d996e SD |
1014 | /* |
1015 | * Lookup and populate the kprobe_blacklist. | |
1016 | * | |
1017 | * Unlike the kretprobe blacklist, we'll need to determine | |
1018 | * the range of addresses that belong to the said functions, | |
1019 | * since a kprobe need not necessarily be at the beginning | |
1020 | * of a function. | |
1021 | */ | |
1022 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { | |
1023 | kprobe_lookup_name(kb->name, addr); | |
1024 | if (!addr) | |
1025 | continue; | |
1026 | ||
1027 | kb->start_addr = (unsigned long)addr; | |
1028 | symbol_name = kallsyms_lookup(kb->start_addr, | |
1029 | &size, &offset, &modname, namebuf); | |
1030 | if (!symbol_name) | |
1031 | kb->range = 0; | |
1032 | else | |
1033 | kb->range = size; | |
1034 | } | |
1035 | ||
f438d914 MH |
1036 | if (kretprobe_blacklist_size) { |
1037 | /* lookup the function address from its name */ | |
1038 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
1039 | kprobe_lookup_name(kretprobe_blacklist[i].name, | |
1040 | kretprobe_blacklist[i].addr); | |
1041 | if (!kretprobe_blacklist[i].addr) | |
1042 | printk("kretprobe: lookup failed: %s\n", | |
1043 | kretprobe_blacklist[i].name); | |
1044 | } | |
1045 | } | |
1046 | ||
bf8f6e5b AM |
1047 | /* By default, kprobes are enabled */ |
1048 | kprobe_enabled = true; | |
1049 | ||
6772926b | 1050 | err = arch_init_kprobes(); |
802eae7c RL |
1051 | if (!err) |
1052 | err = register_die_notifier(&kprobe_exceptions_nb); | |
1053 | ||
8c1c9356 AM |
1054 | if (!err) |
1055 | init_test_probes(); | |
1da177e4 LT |
1056 | return err; |
1057 | } | |
1058 | ||
346fd59b SD |
1059 | #ifdef CONFIG_DEBUG_FS |
1060 | static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p, | |
bf8f6e5b | 1061 | const char *sym, int offset,char *modname) |
346fd59b SD |
1062 | { |
1063 | char *kprobe_type; | |
1064 | ||
1065 | if (p->pre_handler == pre_handler_kretprobe) | |
1066 | kprobe_type = "r"; | |
1067 | else if (p->pre_handler == setjmp_pre_handler) | |
1068 | kprobe_type = "j"; | |
1069 | else | |
1070 | kprobe_type = "k"; | |
1071 | if (sym) | |
1072 | seq_printf(pi, "%p %s %s+0x%x %s\n", p->addr, kprobe_type, | |
1073 | sym, offset, (modname ? modname : " ")); | |
1074 | else | |
1075 | seq_printf(pi, "%p %s %p\n", p->addr, kprobe_type, p->addr); | |
1076 | } | |
1077 | ||
1078 | static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos) | |
1079 | { | |
1080 | return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; | |
1081 | } | |
1082 | ||
1083 | static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) | |
1084 | { | |
1085 | (*pos)++; | |
1086 | if (*pos >= KPROBE_TABLE_SIZE) | |
1087 | return NULL; | |
1088 | return pos; | |
1089 | } | |
1090 | ||
1091 | static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v) | |
1092 | { | |
1093 | /* Nothing to do */ | |
1094 | } | |
1095 | ||
1096 | static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v) | |
1097 | { | |
1098 | struct hlist_head *head; | |
1099 | struct hlist_node *node; | |
1100 | struct kprobe *p, *kp; | |
1101 | const char *sym = NULL; | |
1102 | unsigned int i = *(loff_t *) v; | |
ffb45122 | 1103 | unsigned long offset = 0; |
346fd59b SD |
1104 | char *modname, namebuf[128]; |
1105 | ||
1106 | head = &kprobe_table[i]; | |
1107 | preempt_disable(); | |
1108 | hlist_for_each_entry_rcu(p, node, head, hlist) { | |
ffb45122 | 1109 | sym = kallsyms_lookup((unsigned long)p->addr, NULL, |
346fd59b SD |
1110 | &offset, &modname, namebuf); |
1111 | if (p->pre_handler == aggr_pre_handler) { | |
1112 | list_for_each_entry_rcu(kp, &p->list, list) | |
1113 | report_probe(pi, kp, sym, offset, modname); | |
1114 | } else | |
1115 | report_probe(pi, p, sym, offset, modname); | |
1116 | } | |
1117 | preempt_enable(); | |
1118 | return 0; | |
1119 | } | |
1120 | ||
1121 | static struct seq_operations kprobes_seq_ops = { | |
1122 | .start = kprobe_seq_start, | |
1123 | .next = kprobe_seq_next, | |
1124 | .stop = kprobe_seq_stop, | |
1125 | .show = show_kprobe_addr | |
1126 | }; | |
1127 | ||
1128 | static int __kprobes kprobes_open(struct inode *inode, struct file *filp) | |
1129 | { | |
1130 | return seq_open(filp, &kprobes_seq_ops); | |
1131 | } | |
1132 | ||
1133 | static struct file_operations debugfs_kprobes_operations = { | |
1134 | .open = kprobes_open, | |
1135 | .read = seq_read, | |
1136 | .llseek = seq_lseek, | |
1137 | .release = seq_release, | |
1138 | }; | |
1139 | ||
bf8f6e5b AM |
1140 | static void __kprobes enable_all_kprobes(void) |
1141 | { | |
1142 | struct hlist_head *head; | |
1143 | struct hlist_node *node; | |
1144 | struct kprobe *p; | |
1145 | unsigned int i; | |
1146 | ||
1147 | mutex_lock(&kprobe_mutex); | |
1148 | ||
1149 | /* If kprobes are already enabled, just return */ | |
1150 | if (kprobe_enabled) | |
1151 | goto already_enabled; | |
1152 | ||
bf8f6e5b AM |
1153 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1154 | head = &kprobe_table[i]; | |
1155 | hlist_for_each_entry_rcu(p, node, head, hlist) | |
1156 | arch_arm_kprobe(p); | |
1157 | } | |
1158 | ||
1159 | kprobe_enabled = true; | |
1160 | printk(KERN_INFO "Kprobes globally enabled\n"); | |
1161 | ||
1162 | already_enabled: | |
1163 | mutex_unlock(&kprobe_mutex); | |
1164 | return; | |
1165 | } | |
1166 | ||
1167 | static void __kprobes disable_all_kprobes(void) | |
1168 | { | |
1169 | struct hlist_head *head; | |
1170 | struct hlist_node *node; | |
1171 | struct kprobe *p; | |
1172 | unsigned int i; | |
1173 | ||
1174 | mutex_lock(&kprobe_mutex); | |
1175 | ||
1176 | /* If kprobes are already disabled, just return */ | |
1177 | if (!kprobe_enabled) | |
1178 | goto already_disabled; | |
1179 | ||
1180 | kprobe_enabled = false; | |
1181 | printk(KERN_INFO "Kprobes globally disabled\n"); | |
1182 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { | |
1183 | head = &kprobe_table[i]; | |
1184 | hlist_for_each_entry_rcu(p, node, head, hlist) { | |
1185 | if (!arch_trampoline_kprobe(p)) | |
1186 | arch_disarm_kprobe(p); | |
1187 | } | |
1188 | } | |
1189 | ||
1190 | mutex_unlock(&kprobe_mutex); | |
1191 | /* Allow all currently running kprobes to complete */ | |
1192 | synchronize_sched(); | |
74a0b576 | 1193 | return; |
bf8f6e5b AM |
1194 | |
1195 | already_disabled: | |
1196 | mutex_unlock(&kprobe_mutex); | |
1197 | return; | |
1198 | } | |
1199 | ||
1200 | /* | |
1201 | * XXX: The debugfs bool file interface doesn't allow for callbacks | |
1202 | * when the bool state is switched. We can reuse that facility when | |
1203 | * available | |
1204 | */ | |
1205 | static ssize_t read_enabled_file_bool(struct file *file, | |
1206 | char __user *user_buf, size_t count, loff_t *ppos) | |
1207 | { | |
1208 | char buf[3]; | |
1209 | ||
1210 | if (kprobe_enabled) | |
1211 | buf[0] = '1'; | |
1212 | else | |
1213 | buf[0] = '0'; | |
1214 | buf[1] = '\n'; | |
1215 | buf[2] = 0x00; | |
1216 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); | |
1217 | } | |
1218 | ||
1219 | static ssize_t write_enabled_file_bool(struct file *file, | |
1220 | const char __user *user_buf, size_t count, loff_t *ppos) | |
1221 | { | |
1222 | char buf[32]; | |
1223 | int buf_size; | |
1224 | ||
1225 | buf_size = min(count, (sizeof(buf)-1)); | |
1226 | if (copy_from_user(buf, user_buf, buf_size)) | |
1227 | return -EFAULT; | |
1228 | ||
1229 | switch (buf[0]) { | |
1230 | case 'y': | |
1231 | case 'Y': | |
1232 | case '1': | |
1233 | enable_all_kprobes(); | |
1234 | break; | |
1235 | case 'n': | |
1236 | case 'N': | |
1237 | case '0': | |
1238 | disable_all_kprobes(); | |
1239 | break; | |
1240 | } | |
1241 | ||
1242 | return count; | |
1243 | } | |
1244 | ||
1245 | static struct file_operations fops_kp = { | |
1246 | .read = read_enabled_file_bool, | |
1247 | .write = write_enabled_file_bool, | |
1248 | }; | |
1249 | ||
346fd59b SD |
1250 | static int __kprobes debugfs_kprobe_init(void) |
1251 | { | |
1252 | struct dentry *dir, *file; | |
bf8f6e5b | 1253 | unsigned int value = 1; |
346fd59b SD |
1254 | |
1255 | dir = debugfs_create_dir("kprobes", NULL); | |
1256 | if (!dir) | |
1257 | return -ENOMEM; | |
1258 | ||
e3869792 | 1259 | file = debugfs_create_file("list", 0444, dir, NULL, |
346fd59b SD |
1260 | &debugfs_kprobes_operations); |
1261 | if (!file) { | |
1262 | debugfs_remove(dir); | |
1263 | return -ENOMEM; | |
1264 | } | |
1265 | ||
bf8f6e5b AM |
1266 | file = debugfs_create_file("enabled", 0600, dir, |
1267 | &value, &fops_kp); | |
1268 | if (!file) { | |
1269 | debugfs_remove(dir); | |
1270 | return -ENOMEM; | |
1271 | } | |
1272 | ||
346fd59b SD |
1273 | return 0; |
1274 | } | |
1275 | ||
1276 | late_initcall(debugfs_kprobe_init); | |
1277 | #endif /* CONFIG_DEBUG_FS */ | |
1278 | ||
1279 | module_init(init_kprobes); | |
1da177e4 LT |
1280 | |
1281 | EXPORT_SYMBOL_GPL(register_kprobe); | |
1282 | EXPORT_SYMBOL_GPL(unregister_kprobe); | |
9861668f MH |
1283 | EXPORT_SYMBOL_GPL(register_kprobes); |
1284 | EXPORT_SYMBOL_GPL(unregister_kprobes); | |
1da177e4 LT |
1285 | EXPORT_SYMBOL_GPL(register_jprobe); |
1286 | EXPORT_SYMBOL_GPL(unregister_jprobe); | |
26b31c19 MH |
1287 | EXPORT_SYMBOL_GPL(register_jprobes); |
1288 | EXPORT_SYMBOL_GPL(unregister_jprobes); | |
cd5bfea2 | 1289 | #ifdef CONFIG_KPROBES |
1da177e4 | 1290 | EXPORT_SYMBOL_GPL(jprobe_return); |
cd5bfea2 PC |
1291 | #endif |
1292 | ||
1293 | #ifdef CONFIG_KPROBES | |
b94cce92 HN |
1294 | EXPORT_SYMBOL_GPL(register_kretprobe); |
1295 | EXPORT_SYMBOL_GPL(unregister_kretprobe); | |
4a296e07 MH |
1296 | EXPORT_SYMBOL_GPL(register_kretprobes); |
1297 | EXPORT_SYMBOL_GPL(unregister_kretprobes); | |
cd5bfea2 | 1298 | #endif |