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 | ||
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 | */ | |
82 | struct kprobe_blackpoint kprobe_blacklist[] = { | |
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 | ||
8b0914ea PP |
432 | /* |
433 | * Keep all fields in the kprobe consistent | |
434 | */ | |
435 | static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p) | |
436 | { | |
437 | memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t)); | |
438 | memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn)); | |
439 | } | |
440 | ||
441 | /* | |
442 | * Add the new probe to old_p->list. Fail if this is the | |
443 | * second jprobe at the address - two jprobes can't coexist | |
444 | */ | |
d0aaff97 | 445 | static int __kprobes add_new_kprobe(struct kprobe *old_p, struct kprobe *p) |
8b0914ea | 446 | { |
8b0914ea | 447 | if (p->break_handler) { |
36721656 | 448 | if (old_p->break_handler) |
449 | return -EEXIST; | |
3516a460 | 450 | list_add_tail_rcu(&p->list, &old_p->list); |
36721656 | 451 | old_p->break_handler = aggr_break_handler; |
8b0914ea | 452 | } else |
3516a460 | 453 | list_add_rcu(&p->list, &old_p->list); |
36721656 | 454 | if (p->post_handler && !old_p->post_handler) |
455 | old_p->post_handler = aggr_post_handler; | |
8b0914ea PP |
456 | return 0; |
457 | } | |
458 | ||
64f562c6 AM |
459 | /* |
460 | * Fill in the required fields of the "manager kprobe". Replace the | |
461 | * earlier kprobe in the hlist with the manager kprobe | |
462 | */ | |
463 | static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p) | |
464 | { | |
8b0914ea | 465 | copy_kprobe(p, ap); |
a9ad965e | 466 | flush_insn_slot(ap); |
64f562c6 | 467 | ap->addr = p->addr; |
64f562c6 | 468 | ap->pre_handler = aggr_pre_handler; |
64f562c6 | 469 | ap->fault_handler = aggr_fault_handler; |
36721656 | 470 | if (p->post_handler) |
471 | ap->post_handler = aggr_post_handler; | |
472 | if (p->break_handler) | |
473 | ap->break_handler = aggr_break_handler; | |
64f562c6 AM |
474 | |
475 | INIT_LIST_HEAD(&ap->list); | |
3516a460 | 476 | list_add_rcu(&p->list, &ap->list); |
64f562c6 | 477 | |
adad0f33 | 478 | hlist_replace_rcu(&p->hlist, &ap->hlist); |
64f562c6 AM |
479 | } |
480 | ||
481 | /* | |
482 | * This is the second or subsequent kprobe at the address - handle | |
483 | * the intricacies | |
64f562c6 | 484 | */ |
d0aaff97 PP |
485 | static int __kprobes register_aggr_kprobe(struct kprobe *old_p, |
486 | struct kprobe *p) | |
64f562c6 AM |
487 | { |
488 | int ret = 0; | |
489 | struct kprobe *ap; | |
490 | ||
8b0914ea PP |
491 | if (old_p->pre_handler == aggr_pre_handler) { |
492 | copy_kprobe(old_p, p); | |
493 | ret = add_new_kprobe(old_p, p); | |
64f562c6 | 494 | } else { |
a0d50069 | 495 | ap = kzalloc(sizeof(struct kprobe), GFP_KERNEL); |
64f562c6 AM |
496 | if (!ap) |
497 | return -ENOMEM; | |
498 | add_aggr_kprobe(ap, old_p); | |
8b0914ea PP |
499 | copy_kprobe(ap, p); |
500 | ret = add_new_kprobe(ap, p); | |
64f562c6 AM |
501 | } |
502 | return ret; | |
503 | } | |
504 | ||
d0aaff97 PP |
505 | static int __kprobes in_kprobes_functions(unsigned long addr) |
506 | { | |
3d8d996e SD |
507 | struct kprobe_blackpoint *kb; |
508 | ||
6f716acd CH |
509 | if (addr >= (unsigned long)__kprobes_text_start && |
510 | addr < (unsigned long)__kprobes_text_end) | |
d0aaff97 | 511 | return -EINVAL; |
3d8d996e SD |
512 | /* |
513 | * If there exists a kprobe_blacklist, verify and | |
514 | * fail any probe registration in the prohibited area | |
515 | */ | |
516 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { | |
517 | if (kb->start_addr) { | |
518 | if (addr >= kb->start_addr && | |
519 | addr < (kb->start_addr + kb->range)) | |
520 | return -EINVAL; | |
521 | } | |
522 | } | |
d0aaff97 PP |
523 | return 0; |
524 | } | |
525 | ||
b2a5cd69 MH |
526 | /* |
527 | * If we have a symbol_name argument, look it up and add the offset field | |
528 | * to it. This way, we can specify a relative address to a symbol. | |
529 | */ | |
530 | static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p) | |
531 | { | |
532 | kprobe_opcode_t *addr = p->addr; | |
533 | if (p->symbol_name) { | |
534 | if (addr) | |
535 | return NULL; | |
536 | kprobe_lookup_name(p->symbol_name, addr); | |
537 | } | |
538 | ||
539 | if (!addr) | |
540 | return NULL; | |
541 | return (kprobe_opcode_t *)(((char *)addr) + p->offset); | |
542 | } | |
543 | ||
df019b1d KA |
544 | static int __kprobes __register_kprobe(struct kprobe *p, |
545 | unsigned long called_from) | |
1da177e4 LT |
546 | { |
547 | int ret = 0; | |
64f562c6 | 548 | struct kprobe *old_p; |
df019b1d | 549 | struct module *probed_mod; |
b2a5cd69 | 550 | kprobe_opcode_t *addr; |
b3e55c72 | 551 | |
b2a5cd69 MH |
552 | addr = kprobe_addr(p); |
553 | if (!addr) | |
3a872d89 | 554 | return -EINVAL; |
b2a5cd69 | 555 | p->addr = addr; |
3a872d89 | 556 | |
6f716acd CH |
557 | if (!kernel_text_address((unsigned long) p->addr) || |
558 | in_kprobes_functions((unsigned long) p->addr)) | |
b3e55c72 MB |
559 | return -EINVAL; |
560 | ||
df019b1d | 561 | p->mod_refcounted = 0; |
6f716acd CH |
562 | |
563 | /* | |
564 | * Check if are we probing a module. | |
565 | */ | |
566 | probed_mod = module_text_address((unsigned long) p->addr); | |
567 | if (probed_mod) { | |
df019b1d | 568 | struct module *calling_mod = module_text_address(called_from); |
6f716acd CH |
569 | /* |
570 | * We must allow modules to probe themself and in this case | |
571 | * avoid incrementing the module refcount, so as to allow | |
572 | * unloading of self probing modules. | |
df019b1d | 573 | */ |
6f716acd | 574 | if (calling_mod && calling_mod != probed_mod) { |
df019b1d KA |
575 | if (unlikely(!try_module_get(probed_mod))) |
576 | return -EINVAL; | |
577 | p->mod_refcounted = 1; | |
578 | } else | |
579 | probed_mod = NULL; | |
580 | } | |
1da177e4 | 581 | |
3516a460 | 582 | p->nmissed = 0; |
9861668f | 583 | INIT_LIST_HEAD(&p->list); |
7a7d1cf9 | 584 | mutex_lock(&kprobe_mutex); |
64f562c6 AM |
585 | old_p = get_kprobe(p->addr); |
586 | if (old_p) { | |
587 | ret = register_aggr_kprobe(old_p, p); | |
1da177e4 LT |
588 | goto out; |
589 | } | |
1da177e4 | 590 | |
6f716acd CH |
591 | ret = arch_prepare_kprobe(p); |
592 | if (ret) | |
49a2a1b8 AK |
593 | goto out; |
594 | ||
64f562c6 | 595 | INIT_HLIST_NODE(&p->hlist); |
3516a460 | 596 | hlist_add_head_rcu(&p->hlist, |
1da177e4 LT |
597 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); |
598 | ||
74a0b576 | 599 | if (kprobe_enabled) |
bf8f6e5b | 600 | arch_arm_kprobe(p); |
74a0b576 | 601 | |
1da177e4 | 602 | out: |
7a7d1cf9 | 603 | mutex_unlock(&kprobe_mutex); |
49a2a1b8 | 604 | |
df019b1d KA |
605 | if (ret && probed_mod) |
606 | module_put(probed_mod); | |
1da177e4 LT |
607 | return ret; |
608 | } | |
609 | ||
9861668f MH |
610 | /* |
611 | * Unregister a kprobe without a scheduler synchronization. | |
612 | */ | |
613 | static int __kprobes __unregister_kprobe_top(struct kprobe *p) | |
1da177e4 | 614 | { |
f709b122 | 615 | struct kprobe *old_p, *list_p; |
64f562c6 | 616 | |
64f562c6 | 617 | old_p = get_kprobe(p->addr); |
9861668f MH |
618 | if (unlikely(!old_p)) |
619 | return -EINVAL; | |
620 | ||
f709b122 KA |
621 | if (p != old_p) { |
622 | list_for_each_entry_rcu(list_p, &old_p->list, list) | |
623 | if (list_p == p) | |
624 | /* kprobe p is a valid probe */ | |
625 | goto valid_p; | |
9861668f | 626 | return -EINVAL; |
f709b122 KA |
627 | } |
628 | valid_p: | |
6f716acd CH |
629 | if (old_p == p || |
630 | (old_p->pre_handler == aggr_pre_handler && | |
9861668f | 631 | list_is_singular(&old_p->list))) { |
bf8f6e5b AM |
632 | /* |
633 | * Only probe on the hash list. Disarm only if kprobes are | |
634 | * enabled - otherwise, the breakpoint would already have | |
635 | * been removed. We save on flushing icache. | |
636 | */ | |
637 | if (kprobe_enabled) | |
638 | arch_disarm_kprobe(p); | |
49a2a1b8 | 639 | hlist_del_rcu(&old_p->hlist); |
49a2a1b8 | 640 | } else { |
9861668f MH |
641 | if (p->break_handler) |
642 | old_p->break_handler = NULL; | |
643 | if (p->post_handler) { | |
644 | list_for_each_entry_rcu(list_p, &old_p->list, list) { | |
645 | if ((list_p != p) && (list_p->post_handler)) | |
646 | goto noclean; | |
647 | } | |
648 | old_p->post_handler = NULL; | |
649 | } | |
650 | noclean: | |
49a2a1b8 | 651 | list_del_rcu(&p->list); |
49a2a1b8 | 652 | } |
9861668f MH |
653 | return 0; |
654 | } | |
3516a460 | 655 | |
9861668f MH |
656 | static void __kprobes __unregister_kprobe_bottom(struct kprobe *p) |
657 | { | |
658 | struct module *mod; | |
659 | struct kprobe *old_p; | |
b3e55c72 | 660 | |
6f716acd CH |
661 | if (p->mod_refcounted) { |
662 | mod = module_text_address((unsigned long)p->addr); | |
663 | if (mod) | |
664 | module_put(mod); | |
665 | } | |
b3e55c72 | 666 | |
9861668f MH |
667 | if (list_empty(&p->list) || list_is_singular(&p->list)) { |
668 | if (!list_empty(&p->list)) { | |
669 | /* "p" is the last child of an aggr_kprobe */ | |
670 | old_p = list_entry(p->list.next, struct kprobe, list); | |
671 | list_del(&p->list); | |
3516a460 | 672 | kfree(old_p); |
49a2a1b8 | 673 | } |
0498b635 | 674 | arch_remove_kprobe(p); |
9861668f MH |
675 | } |
676 | } | |
677 | ||
678 | static int __register_kprobes(struct kprobe **kps, int num, | |
679 | unsigned long called_from) | |
680 | { | |
681 | int i, ret = 0; | |
682 | ||
683 | if (num <= 0) | |
684 | return -EINVAL; | |
685 | for (i = 0; i < num; i++) { | |
686 | ret = __register_kprobe(kps[i], called_from); | |
687 | if (ret < 0 && i > 0) { | |
688 | unregister_kprobes(kps, i); | |
689 | break; | |
36721656 | 690 | } |
49a2a1b8 | 691 | } |
9861668f MH |
692 | return ret; |
693 | } | |
694 | ||
695 | /* | |
696 | * Registration and unregistration functions for kprobe. | |
697 | */ | |
698 | int __kprobes register_kprobe(struct kprobe *p) | |
699 | { | |
700 | return __register_kprobes(&p, 1, | |
701 | (unsigned long)__builtin_return_address(0)); | |
702 | } | |
703 | ||
704 | void __kprobes unregister_kprobe(struct kprobe *p) | |
705 | { | |
706 | unregister_kprobes(&p, 1); | |
707 | } | |
708 | ||
709 | int __kprobes register_kprobes(struct kprobe **kps, int num) | |
710 | { | |
711 | return __register_kprobes(kps, num, | |
712 | (unsigned long)__builtin_return_address(0)); | |
713 | } | |
714 | ||
715 | void __kprobes unregister_kprobes(struct kprobe **kps, int num) | |
716 | { | |
717 | int i; | |
718 | ||
719 | if (num <= 0) | |
720 | return; | |
721 | mutex_lock(&kprobe_mutex); | |
722 | for (i = 0; i < num; i++) | |
723 | if (__unregister_kprobe_top(kps[i]) < 0) | |
724 | kps[i]->addr = NULL; | |
725 | mutex_unlock(&kprobe_mutex); | |
726 | ||
727 | synchronize_sched(); | |
728 | for (i = 0; i < num; i++) | |
729 | if (kps[i]->addr) | |
730 | __unregister_kprobe_bottom(kps[i]); | |
1da177e4 LT |
731 | } |
732 | ||
733 | static struct notifier_block kprobe_exceptions_nb = { | |
3d5631e0 AK |
734 | .notifier_call = kprobe_exceptions_notify, |
735 | .priority = 0x7fffffff /* we need to be notified first */ | |
736 | }; | |
737 | ||
3d7e3382 ME |
738 | unsigned long __weak arch_deref_entry_point(void *entry) |
739 | { | |
740 | return (unsigned long)entry; | |
741 | } | |
1da177e4 | 742 | |
d0aaff97 | 743 | int __kprobes register_jprobe(struct jprobe *jp) |
1da177e4 | 744 | { |
3d7e3382 ME |
745 | unsigned long addr = arch_deref_entry_point(jp->entry); |
746 | ||
747 | if (!kernel_text_address(addr)) | |
748 | return -EINVAL; | |
749 | ||
1da177e4 LT |
750 | /* Todo: Verify probepoint is a function entry point */ |
751 | jp->kp.pre_handler = setjmp_pre_handler; | |
752 | jp->kp.break_handler = longjmp_break_handler; | |
753 | ||
df019b1d KA |
754 | return __register_kprobe(&jp->kp, |
755 | (unsigned long)__builtin_return_address(0)); | |
1da177e4 LT |
756 | } |
757 | ||
d0aaff97 | 758 | void __kprobes unregister_jprobe(struct jprobe *jp) |
1da177e4 LT |
759 | { |
760 | unregister_kprobe(&jp->kp); | |
761 | } | |
762 | ||
9edddaa2 | 763 | #ifdef CONFIG_KRETPROBES |
e65cefe8 AB |
764 | /* |
765 | * This kprobe pre_handler is registered with every kretprobe. When probe | |
766 | * hits it will set up the return probe. | |
767 | */ | |
768 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, | |
769 | struct pt_regs *regs) | |
770 | { | |
771 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); | |
772 | unsigned long flags = 0; | |
773 | ||
774 | /*TODO: consider to only swap the RA after the last pre_handler fired */ | |
775 | spin_lock_irqsave(&kretprobe_lock, flags); | |
4c4308cb CH |
776 | if (!hlist_empty(&rp->free_instances)) { |
777 | struct kretprobe_instance *ri; | |
778 | ||
779 | ri = hlist_entry(rp->free_instances.first, | |
780 | struct kretprobe_instance, uflist); | |
781 | ri->rp = rp; | |
782 | ri->task = current; | |
f47cd9b5 AS |
783 | |
784 | if (rp->entry_handler && rp->entry_handler(ri, regs)) { | |
785 | spin_unlock_irqrestore(&kretprobe_lock, flags); | |
786 | return 0; | |
787 | } | |
788 | ||
4c4308cb CH |
789 | arch_prepare_kretprobe(ri, regs); |
790 | ||
791 | /* XXX(hch): why is there no hlist_move_head? */ | |
792 | hlist_del(&ri->uflist); | |
793 | hlist_add_head(&ri->uflist, &ri->rp->used_instances); | |
794 | hlist_add_head(&ri->hlist, kretprobe_inst_table_head(ri->task)); | |
795 | } else | |
796 | rp->nmissed++; | |
e65cefe8 AB |
797 | spin_unlock_irqrestore(&kretprobe_lock, flags); |
798 | return 0; | |
799 | } | |
800 | ||
d0aaff97 | 801 | int __kprobes register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
802 | { |
803 | int ret = 0; | |
804 | struct kretprobe_instance *inst; | |
805 | int i; | |
b2a5cd69 | 806 | void *addr; |
f438d914 MH |
807 | |
808 | if (kretprobe_blacklist_size) { | |
b2a5cd69 MH |
809 | addr = kprobe_addr(&rp->kp); |
810 | if (!addr) | |
811 | return -EINVAL; | |
f438d914 MH |
812 | |
813 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
814 | if (kretprobe_blacklist[i].addr == addr) | |
815 | return -EINVAL; | |
816 | } | |
817 | } | |
b94cce92 HN |
818 | |
819 | rp->kp.pre_handler = pre_handler_kretprobe; | |
7522a842 AM |
820 | rp->kp.post_handler = NULL; |
821 | rp->kp.fault_handler = NULL; | |
822 | rp->kp.break_handler = NULL; | |
b94cce92 HN |
823 | |
824 | /* Pre-allocate memory for max kretprobe instances */ | |
825 | if (rp->maxactive <= 0) { | |
826 | #ifdef CONFIG_PREEMPT | |
827 | rp->maxactive = max(10, 2 * NR_CPUS); | |
828 | #else | |
829 | rp->maxactive = NR_CPUS; | |
830 | #endif | |
831 | } | |
832 | INIT_HLIST_HEAD(&rp->used_instances); | |
833 | INIT_HLIST_HEAD(&rp->free_instances); | |
834 | for (i = 0; i < rp->maxactive; i++) { | |
f47cd9b5 AS |
835 | inst = kmalloc(sizeof(struct kretprobe_instance) + |
836 | rp->data_size, GFP_KERNEL); | |
b94cce92 HN |
837 | if (inst == NULL) { |
838 | free_rp_inst(rp); | |
839 | return -ENOMEM; | |
840 | } | |
841 | INIT_HLIST_NODE(&inst->uflist); | |
842 | hlist_add_head(&inst->uflist, &rp->free_instances); | |
843 | } | |
844 | ||
845 | rp->nmissed = 0; | |
846 | /* Establish function entry probe point */ | |
df019b1d KA |
847 | if ((ret = __register_kprobe(&rp->kp, |
848 | (unsigned long)__builtin_return_address(0))) != 0) | |
b94cce92 HN |
849 | free_rp_inst(rp); |
850 | return ret; | |
851 | } | |
852 | ||
9edddaa2 | 853 | #else /* CONFIG_KRETPROBES */ |
d0aaff97 | 854 | int __kprobes register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
855 | { |
856 | return -ENOSYS; | |
857 | } | |
858 | ||
346fd59b SD |
859 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, |
860 | struct pt_regs *regs) | |
861 | { | |
862 | return 0; | |
863 | } | |
9edddaa2 | 864 | #endif /* CONFIG_KRETPROBES */ |
b94cce92 | 865 | |
d0aaff97 | 866 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
867 | { |
868 | unsigned long flags; | |
869 | struct kretprobe_instance *ri; | |
4c4308cb | 870 | struct hlist_node *pos, *next; |
b94cce92 HN |
871 | |
872 | unregister_kprobe(&rp->kp); | |
4c4308cb | 873 | |
b94cce92 | 874 | /* No race here */ |
3516a460 | 875 | spin_lock_irqsave(&kretprobe_lock, flags); |
4c4308cb | 876 | hlist_for_each_entry_safe(ri, pos, next, &rp->used_instances, uflist) { |
b94cce92 HN |
877 | ri->rp = NULL; |
878 | hlist_del(&ri->uflist); | |
879 | } | |
3516a460 | 880 | spin_unlock_irqrestore(&kretprobe_lock, flags); |
278ff953 | 881 | free_rp_inst(rp); |
b94cce92 HN |
882 | } |
883 | ||
1da177e4 LT |
884 | static int __init init_kprobes(void) |
885 | { | |
886 | int i, err = 0; | |
3d8d996e SD |
887 | unsigned long offset = 0, size = 0; |
888 | char *modname, namebuf[128]; | |
889 | const char *symbol_name; | |
890 | void *addr; | |
891 | struct kprobe_blackpoint *kb; | |
1da177e4 LT |
892 | |
893 | /* FIXME allocate the probe table, currently defined statically */ | |
894 | /* initialize all list heads */ | |
b94cce92 | 895 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1da177e4 | 896 | INIT_HLIST_HEAD(&kprobe_table[i]); |
b94cce92 HN |
897 | INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
898 | } | |
1da177e4 | 899 | |
3d8d996e SD |
900 | /* |
901 | * Lookup and populate the kprobe_blacklist. | |
902 | * | |
903 | * Unlike the kretprobe blacklist, we'll need to determine | |
904 | * the range of addresses that belong to the said functions, | |
905 | * since a kprobe need not necessarily be at the beginning | |
906 | * of a function. | |
907 | */ | |
908 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { | |
909 | kprobe_lookup_name(kb->name, addr); | |
910 | if (!addr) | |
911 | continue; | |
912 | ||
913 | kb->start_addr = (unsigned long)addr; | |
914 | symbol_name = kallsyms_lookup(kb->start_addr, | |
915 | &size, &offset, &modname, namebuf); | |
916 | if (!symbol_name) | |
917 | kb->range = 0; | |
918 | else | |
919 | kb->range = size; | |
920 | } | |
921 | ||
f438d914 MH |
922 | if (kretprobe_blacklist_size) { |
923 | /* lookup the function address from its name */ | |
924 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
925 | kprobe_lookup_name(kretprobe_blacklist[i].name, | |
926 | kretprobe_blacklist[i].addr); | |
927 | if (!kretprobe_blacklist[i].addr) | |
928 | printk("kretprobe: lookup failed: %s\n", | |
929 | kretprobe_blacklist[i].name); | |
930 | } | |
931 | } | |
932 | ||
bf8f6e5b AM |
933 | /* By default, kprobes are enabled */ |
934 | kprobe_enabled = true; | |
935 | ||
6772926b | 936 | err = arch_init_kprobes(); |
802eae7c RL |
937 | if (!err) |
938 | err = register_die_notifier(&kprobe_exceptions_nb); | |
939 | ||
8c1c9356 AM |
940 | if (!err) |
941 | init_test_probes(); | |
1da177e4 LT |
942 | return err; |
943 | } | |
944 | ||
346fd59b SD |
945 | #ifdef CONFIG_DEBUG_FS |
946 | static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p, | |
bf8f6e5b | 947 | const char *sym, int offset,char *modname) |
346fd59b SD |
948 | { |
949 | char *kprobe_type; | |
950 | ||
951 | if (p->pre_handler == pre_handler_kretprobe) | |
952 | kprobe_type = "r"; | |
953 | else if (p->pre_handler == setjmp_pre_handler) | |
954 | kprobe_type = "j"; | |
955 | else | |
956 | kprobe_type = "k"; | |
957 | if (sym) | |
958 | seq_printf(pi, "%p %s %s+0x%x %s\n", p->addr, kprobe_type, | |
959 | sym, offset, (modname ? modname : " ")); | |
960 | else | |
961 | seq_printf(pi, "%p %s %p\n", p->addr, kprobe_type, p->addr); | |
962 | } | |
963 | ||
964 | static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos) | |
965 | { | |
966 | return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; | |
967 | } | |
968 | ||
969 | static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) | |
970 | { | |
971 | (*pos)++; | |
972 | if (*pos >= KPROBE_TABLE_SIZE) | |
973 | return NULL; | |
974 | return pos; | |
975 | } | |
976 | ||
977 | static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v) | |
978 | { | |
979 | /* Nothing to do */ | |
980 | } | |
981 | ||
982 | static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v) | |
983 | { | |
984 | struct hlist_head *head; | |
985 | struct hlist_node *node; | |
986 | struct kprobe *p, *kp; | |
987 | const char *sym = NULL; | |
988 | unsigned int i = *(loff_t *) v; | |
ffb45122 | 989 | unsigned long offset = 0; |
346fd59b SD |
990 | char *modname, namebuf[128]; |
991 | ||
992 | head = &kprobe_table[i]; | |
993 | preempt_disable(); | |
994 | hlist_for_each_entry_rcu(p, node, head, hlist) { | |
ffb45122 | 995 | sym = kallsyms_lookup((unsigned long)p->addr, NULL, |
346fd59b SD |
996 | &offset, &modname, namebuf); |
997 | if (p->pre_handler == aggr_pre_handler) { | |
998 | list_for_each_entry_rcu(kp, &p->list, list) | |
999 | report_probe(pi, kp, sym, offset, modname); | |
1000 | } else | |
1001 | report_probe(pi, p, sym, offset, modname); | |
1002 | } | |
1003 | preempt_enable(); | |
1004 | return 0; | |
1005 | } | |
1006 | ||
1007 | static struct seq_operations kprobes_seq_ops = { | |
1008 | .start = kprobe_seq_start, | |
1009 | .next = kprobe_seq_next, | |
1010 | .stop = kprobe_seq_stop, | |
1011 | .show = show_kprobe_addr | |
1012 | }; | |
1013 | ||
1014 | static int __kprobes kprobes_open(struct inode *inode, struct file *filp) | |
1015 | { | |
1016 | return seq_open(filp, &kprobes_seq_ops); | |
1017 | } | |
1018 | ||
1019 | static struct file_operations debugfs_kprobes_operations = { | |
1020 | .open = kprobes_open, | |
1021 | .read = seq_read, | |
1022 | .llseek = seq_lseek, | |
1023 | .release = seq_release, | |
1024 | }; | |
1025 | ||
bf8f6e5b AM |
1026 | static void __kprobes enable_all_kprobes(void) |
1027 | { | |
1028 | struct hlist_head *head; | |
1029 | struct hlist_node *node; | |
1030 | struct kprobe *p; | |
1031 | unsigned int i; | |
1032 | ||
1033 | mutex_lock(&kprobe_mutex); | |
1034 | ||
1035 | /* If kprobes are already enabled, just return */ | |
1036 | if (kprobe_enabled) | |
1037 | goto already_enabled; | |
1038 | ||
bf8f6e5b AM |
1039 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1040 | head = &kprobe_table[i]; | |
1041 | hlist_for_each_entry_rcu(p, node, head, hlist) | |
1042 | arch_arm_kprobe(p); | |
1043 | } | |
1044 | ||
1045 | kprobe_enabled = true; | |
1046 | printk(KERN_INFO "Kprobes globally enabled\n"); | |
1047 | ||
1048 | already_enabled: | |
1049 | mutex_unlock(&kprobe_mutex); | |
1050 | return; | |
1051 | } | |
1052 | ||
1053 | static void __kprobes disable_all_kprobes(void) | |
1054 | { | |
1055 | struct hlist_head *head; | |
1056 | struct hlist_node *node; | |
1057 | struct kprobe *p; | |
1058 | unsigned int i; | |
1059 | ||
1060 | mutex_lock(&kprobe_mutex); | |
1061 | ||
1062 | /* If kprobes are already disabled, just return */ | |
1063 | if (!kprobe_enabled) | |
1064 | goto already_disabled; | |
1065 | ||
1066 | kprobe_enabled = false; | |
1067 | printk(KERN_INFO "Kprobes globally disabled\n"); | |
1068 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { | |
1069 | head = &kprobe_table[i]; | |
1070 | hlist_for_each_entry_rcu(p, node, head, hlist) { | |
1071 | if (!arch_trampoline_kprobe(p)) | |
1072 | arch_disarm_kprobe(p); | |
1073 | } | |
1074 | } | |
1075 | ||
1076 | mutex_unlock(&kprobe_mutex); | |
1077 | /* Allow all currently running kprobes to complete */ | |
1078 | synchronize_sched(); | |
74a0b576 | 1079 | return; |
bf8f6e5b AM |
1080 | |
1081 | already_disabled: | |
1082 | mutex_unlock(&kprobe_mutex); | |
1083 | return; | |
1084 | } | |
1085 | ||
1086 | /* | |
1087 | * XXX: The debugfs bool file interface doesn't allow for callbacks | |
1088 | * when the bool state is switched. We can reuse that facility when | |
1089 | * available | |
1090 | */ | |
1091 | static ssize_t read_enabled_file_bool(struct file *file, | |
1092 | char __user *user_buf, size_t count, loff_t *ppos) | |
1093 | { | |
1094 | char buf[3]; | |
1095 | ||
1096 | if (kprobe_enabled) | |
1097 | buf[0] = '1'; | |
1098 | else | |
1099 | buf[0] = '0'; | |
1100 | buf[1] = '\n'; | |
1101 | buf[2] = 0x00; | |
1102 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); | |
1103 | } | |
1104 | ||
1105 | static ssize_t write_enabled_file_bool(struct file *file, | |
1106 | const char __user *user_buf, size_t count, loff_t *ppos) | |
1107 | { | |
1108 | char buf[32]; | |
1109 | int buf_size; | |
1110 | ||
1111 | buf_size = min(count, (sizeof(buf)-1)); | |
1112 | if (copy_from_user(buf, user_buf, buf_size)) | |
1113 | return -EFAULT; | |
1114 | ||
1115 | switch (buf[0]) { | |
1116 | case 'y': | |
1117 | case 'Y': | |
1118 | case '1': | |
1119 | enable_all_kprobes(); | |
1120 | break; | |
1121 | case 'n': | |
1122 | case 'N': | |
1123 | case '0': | |
1124 | disable_all_kprobes(); | |
1125 | break; | |
1126 | } | |
1127 | ||
1128 | return count; | |
1129 | } | |
1130 | ||
1131 | static struct file_operations fops_kp = { | |
1132 | .read = read_enabled_file_bool, | |
1133 | .write = write_enabled_file_bool, | |
1134 | }; | |
1135 | ||
346fd59b SD |
1136 | static int __kprobes debugfs_kprobe_init(void) |
1137 | { | |
1138 | struct dentry *dir, *file; | |
bf8f6e5b | 1139 | unsigned int value = 1; |
346fd59b SD |
1140 | |
1141 | dir = debugfs_create_dir("kprobes", NULL); | |
1142 | if (!dir) | |
1143 | return -ENOMEM; | |
1144 | ||
e3869792 | 1145 | file = debugfs_create_file("list", 0444, dir, NULL, |
346fd59b SD |
1146 | &debugfs_kprobes_operations); |
1147 | if (!file) { | |
1148 | debugfs_remove(dir); | |
1149 | return -ENOMEM; | |
1150 | } | |
1151 | ||
bf8f6e5b AM |
1152 | file = debugfs_create_file("enabled", 0600, dir, |
1153 | &value, &fops_kp); | |
1154 | if (!file) { | |
1155 | debugfs_remove(dir); | |
1156 | return -ENOMEM; | |
1157 | } | |
1158 | ||
346fd59b SD |
1159 | return 0; |
1160 | } | |
1161 | ||
1162 | late_initcall(debugfs_kprobe_init); | |
1163 | #endif /* CONFIG_DEBUG_FS */ | |
1164 | ||
1165 | module_init(init_kprobes); | |
1da177e4 LT |
1166 | |
1167 | EXPORT_SYMBOL_GPL(register_kprobe); | |
1168 | EXPORT_SYMBOL_GPL(unregister_kprobe); | |
9861668f MH |
1169 | EXPORT_SYMBOL_GPL(register_kprobes); |
1170 | EXPORT_SYMBOL_GPL(unregister_kprobes); | |
1da177e4 LT |
1171 | EXPORT_SYMBOL_GPL(register_jprobe); |
1172 | EXPORT_SYMBOL_GPL(unregister_jprobe); | |
cd5bfea2 | 1173 | #ifdef CONFIG_KPROBES |
1da177e4 | 1174 | EXPORT_SYMBOL_GPL(jprobe_return); |
cd5bfea2 PC |
1175 | #endif |
1176 | ||
1177 | #ifdef CONFIG_KPROBES | |
b94cce92 HN |
1178 | EXPORT_SYMBOL_GPL(register_kretprobe); |
1179 | EXPORT_SYMBOL_GPL(unregister_kretprobe); | |
cd5bfea2 | 1180 | #endif |