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 | ||
7a7d1cf9 | 72 | DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */ |
e6584523 | 73 | static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; |
ef53d9c5 S |
74 | static struct { |
75 | spinlock_t lock ____cacheline_aligned; | |
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 | ||
9ec4b1f3 | 118 | static struct hlist_head kprobe_insn_pages; |
b4c6c34a MH |
119 | static int kprobe_garbage_slots; |
120 | static int collect_garbage_slots(void); | |
121 | ||
122 | static int __kprobes check_safety(void) | |
123 | { | |
124 | int ret = 0; | |
125 | #if defined(CONFIG_PREEMPT) && defined(CONFIG_PM) | |
126 | ret = freeze_processes(); | |
127 | if (ret == 0) { | |
128 | struct task_struct *p, *q; | |
129 | do_each_thread(p, q) { | |
130 | if (p != current && p->state == TASK_RUNNING && | |
131 | p->pid != 0) { | |
132 | printk("Check failed: %s is running\n",p->comm); | |
133 | ret = -1; | |
134 | goto loop_end; | |
135 | } | |
136 | } while_each_thread(p, q); | |
137 | } | |
138 | loop_end: | |
139 | thaw_processes(); | |
140 | #else | |
141 | synchronize_sched(); | |
142 | #endif | |
143 | return ret; | |
144 | } | |
9ec4b1f3 AM |
145 | |
146 | /** | |
147 | * get_insn_slot() - Find a slot on an executable page for an instruction. | |
148 | * We allocate an executable page if there's no room on existing ones. | |
149 | */ | |
d0aaff97 | 150 | kprobe_opcode_t __kprobes *get_insn_slot(void) |
9ec4b1f3 AM |
151 | { |
152 | struct kprobe_insn_page *kip; | |
153 | struct hlist_node *pos; | |
154 | ||
6f716acd | 155 | retry: |
b0bb5016 | 156 | hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) { |
9ec4b1f3 AM |
157 | if (kip->nused < INSNS_PER_PAGE) { |
158 | int i; | |
159 | for (i = 0; i < INSNS_PER_PAGE; i++) { | |
ab40c5c6 MH |
160 | if (kip->slot_used[i] == SLOT_CLEAN) { |
161 | kip->slot_used[i] = SLOT_USED; | |
9ec4b1f3 AM |
162 | kip->nused++; |
163 | return kip->insns + (i * MAX_INSN_SIZE); | |
164 | } | |
165 | } | |
166 | /* Surprise! No unused slots. Fix kip->nused. */ | |
167 | kip->nused = INSNS_PER_PAGE; | |
168 | } | |
169 | } | |
170 | ||
b4c6c34a MH |
171 | /* If there are any garbage slots, collect it and try again. */ |
172 | if (kprobe_garbage_slots && collect_garbage_slots() == 0) { | |
173 | goto retry; | |
174 | } | |
175 | /* All out of space. Need to allocate a new page. Use slot 0. */ | |
9ec4b1f3 | 176 | kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL); |
6f716acd | 177 | if (!kip) |
9ec4b1f3 | 178 | return NULL; |
9ec4b1f3 AM |
179 | |
180 | /* | |
181 | * Use module_alloc so this page is within +/- 2GB of where the | |
182 | * kernel image and loaded module images reside. This is required | |
183 | * so x86_64 can correctly handle the %rip-relative fixups. | |
184 | */ | |
185 | kip->insns = module_alloc(PAGE_SIZE); | |
186 | if (!kip->insns) { | |
187 | kfree(kip); | |
188 | return NULL; | |
189 | } | |
190 | INIT_HLIST_NODE(&kip->hlist); | |
191 | hlist_add_head(&kip->hlist, &kprobe_insn_pages); | |
ab40c5c6 MH |
192 | memset(kip->slot_used, SLOT_CLEAN, INSNS_PER_PAGE); |
193 | kip->slot_used[0] = SLOT_USED; | |
9ec4b1f3 | 194 | kip->nused = 1; |
b4c6c34a | 195 | kip->ngarbage = 0; |
9ec4b1f3 AM |
196 | return kip->insns; |
197 | } | |
198 | ||
b4c6c34a MH |
199 | /* Return 1 if all garbages are collected, otherwise 0. */ |
200 | static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx) | |
201 | { | |
ab40c5c6 | 202 | kip->slot_used[idx] = SLOT_CLEAN; |
b4c6c34a MH |
203 | kip->nused--; |
204 | if (kip->nused == 0) { | |
205 | /* | |
206 | * Page is no longer in use. Free it unless | |
207 | * it's the last one. We keep the last one | |
208 | * so as not to have to set it up again the | |
209 | * next time somebody inserts a probe. | |
210 | */ | |
211 | hlist_del(&kip->hlist); | |
212 | if (hlist_empty(&kprobe_insn_pages)) { | |
213 | INIT_HLIST_NODE(&kip->hlist); | |
214 | hlist_add_head(&kip->hlist, | |
215 | &kprobe_insn_pages); | |
216 | } else { | |
217 | module_free(NULL, kip->insns); | |
218 | kfree(kip); | |
219 | } | |
220 | return 1; | |
221 | } | |
222 | return 0; | |
223 | } | |
224 | ||
225 | static int __kprobes collect_garbage_slots(void) | |
226 | { | |
227 | struct kprobe_insn_page *kip; | |
228 | struct hlist_node *pos, *next; | |
229 | ||
230 | /* Ensure no-one is preepmted on the garbages */ | |
231 | if (check_safety() != 0) | |
232 | return -EAGAIN; | |
233 | ||
b0bb5016 | 234 | hlist_for_each_entry_safe(kip, pos, next, &kprobe_insn_pages, hlist) { |
b4c6c34a | 235 | int i; |
b4c6c34a MH |
236 | if (kip->ngarbage == 0) |
237 | continue; | |
238 | kip->ngarbage = 0; /* we will collect all garbages */ | |
239 | for (i = 0; i < INSNS_PER_PAGE; i++) { | |
ab40c5c6 | 240 | if (kip->slot_used[i] == SLOT_DIRTY && |
b4c6c34a MH |
241 | collect_one_slot(kip, i)) |
242 | break; | |
243 | } | |
244 | } | |
245 | kprobe_garbage_slots = 0; | |
246 | return 0; | |
247 | } | |
248 | ||
249 | void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty) | |
9ec4b1f3 AM |
250 | { |
251 | struct kprobe_insn_page *kip; | |
252 | struct hlist_node *pos; | |
253 | ||
b0bb5016 | 254 | hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) { |
9ec4b1f3 AM |
255 | if (kip->insns <= slot && |
256 | slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) { | |
257 | int i = (slot - kip->insns) / MAX_INSN_SIZE; | |
b4c6c34a | 258 | if (dirty) { |
ab40c5c6 | 259 | kip->slot_used[i] = SLOT_DIRTY; |
b4c6c34a MH |
260 | kip->ngarbage++; |
261 | } else { | |
262 | collect_one_slot(kip, i); | |
9ec4b1f3 | 263 | } |
b4c6c34a | 264 | break; |
9ec4b1f3 AM |
265 | } |
266 | } | |
6f716acd CH |
267 | |
268 | if (dirty && ++kprobe_garbage_slots > INSNS_PER_PAGE) | |
b4c6c34a | 269 | collect_garbage_slots(); |
9ec4b1f3 | 270 | } |
2d14e39d | 271 | #endif |
9ec4b1f3 | 272 | |
e6584523 AM |
273 | /* We have preemption disabled.. so it is safe to use __ versions */ |
274 | static inline void set_kprobe_instance(struct kprobe *kp) | |
275 | { | |
276 | __get_cpu_var(kprobe_instance) = kp; | |
277 | } | |
278 | ||
279 | static inline void reset_kprobe_instance(void) | |
280 | { | |
281 | __get_cpu_var(kprobe_instance) = NULL; | |
282 | } | |
283 | ||
3516a460 AM |
284 | /* |
285 | * This routine is called either: | |
49a2a1b8 | 286 | * - under the kprobe_mutex - during kprobe_[un]register() |
3516a460 | 287 | * OR |
d217d545 | 288 | * - with preemption disabled - from arch/xxx/kernel/kprobes.c |
3516a460 | 289 | */ |
d0aaff97 | 290 | struct kprobe __kprobes *get_kprobe(void *addr) |
1da177e4 LT |
291 | { |
292 | struct hlist_head *head; | |
293 | struct hlist_node *node; | |
3516a460 | 294 | struct kprobe *p; |
1da177e4 LT |
295 | |
296 | head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; | |
3516a460 | 297 | hlist_for_each_entry_rcu(p, node, head, hlist) { |
1da177e4 LT |
298 | if (p->addr == addr) |
299 | return p; | |
300 | } | |
301 | return NULL; | |
302 | } | |
303 | ||
64f562c6 AM |
304 | /* |
305 | * Aggregate handlers for multiple kprobes support - these handlers | |
306 | * take care of invoking the individual kprobe handlers on p->list | |
307 | */ | |
d0aaff97 | 308 | static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
64f562c6 AM |
309 | { |
310 | struct kprobe *kp; | |
311 | ||
3516a460 | 312 | list_for_each_entry_rcu(kp, &p->list, list) { |
64f562c6 | 313 | if (kp->pre_handler) { |
e6584523 | 314 | set_kprobe_instance(kp); |
8b0914ea PP |
315 | if (kp->pre_handler(kp, regs)) |
316 | return 1; | |
64f562c6 | 317 | } |
e6584523 | 318 | reset_kprobe_instance(); |
64f562c6 AM |
319 | } |
320 | return 0; | |
321 | } | |
322 | ||
d0aaff97 PP |
323 | static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
324 | unsigned long flags) | |
64f562c6 AM |
325 | { |
326 | struct kprobe *kp; | |
327 | ||
3516a460 | 328 | list_for_each_entry_rcu(kp, &p->list, list) { |
64f562c6 | 329 | if (kp->post_handler) { |
e6584523 | 330 | set_kprobe_instance(kp); |
64f562c6 | 331 | kp->post_handler(kp, regs, flags); |
e6584523 | 332 | reset_kprobe_instance(); |
64f562c6 AM |
333 | } |
334 | } | |
64f562c6 AM |
335 | } |
336 | ||
d0aaff97 PP |
337 | static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, |
338 | int trapnr) | |
64f562c6 | 339 | { |
e6584523 AM |
340 | struct kprobe *cur = __get_cpu_var(kprobe_instance); |
341 | ||
64f562c6 AM |
342 | /* |
343 | * if we faulted "during" the execution of a user specified | |
344 | * probe handler, invoke just that probe's fault handler | |
345 | */ | |
e6584523 AM |
346 | if (cur && cur->fault_handler) { |
347 | if (cur->fault_handler(cur, regs, trapnr)) | |
64f562c6 AM |
348 | return 1; |
349 | } | |
350 | return 0; | |
351 | } | |
352 | ||
d0aaff97 | 353 | static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs) |
8b0914ea | 354 | { |
e6584523 AM |
355 | struct kprobe *cur = __get_cpu_var(kprobe_instance); |
356 | int ret = 0; | |
357 | ||
358 | if (cur && cur->break_handler) { | |
359 | if (cur->break_handler(cur, regs)) | |
360 | ret = 1; | |
8b0914ea | 361 | } |
e6584523 AM |
362 | reset_kprobe_instance(); |
363 | return ret; | |
8b0914ea PP |
364 | } |
365 | ||
bf8d5c52 KA |
366 | /* Walks the list and increments nmissed count for multiprobe case */ |
367 | void __kprobes kprobes_inc_nmissed_count(struct kprobe *p) | |
368 | { | |
369 | struct kprobe *kp; | |
370 | if (p->pre_handler != aggr_pre_handler) { | |
371 | p->nmissed++; | |
372 | } else { | |
373 | list_for_each_entry_rcu(kp, &p->list, list) | |
374 | kp->nmissed++; | |
375 | } | |
376 | return; | |
377 | } | |
378 | ||
99219a3f | 379 | void __kprobes recycle_rp_inst(struct kretprobe_instance *ri, |
380 | struct hlist_head *head) | |
b94cce92 | 381 | { |
ef53d9c5 S |
382 | struct kretprobe *rp = ri->rp; |
383 | ||
b94cce92 HN |
384 | /* remove rp inst off the rprobe_inst_table */ |
385 | hlist_del(&ri->hlist); | |
ef53d9c5 S |
386 | INIT_HLIST_NODE(&ri->hlist); |
387 | if (likely(rp)) { | |
388 | spin_lock(&rp->lock); | |
389 | hlist_add_head(&ri->hlist, &rp->free_instances); | |
390 | spin_unlock(&rp->lock); | |
b94cce92 HN |
391 | } else |
392 | /* Unregistering */ | |
99219a3f | 393 | hlist_add_head(&ri->hlist, head); |
b94cce92 HN |
394 | } |
395 | ||
ef53d9c5 S |
396 | void kretprobe_hash_lock(struct task_struct *tsk, |
397 | struct hlist_head **head, unsigned long *flags) | |
398 | { | |
399 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); | |
400 | spinlock_t *hlist_lock; | |
401 | ||
402 | *head = &kretprobe_inst_table[hash]; | |
403 | hlist_lock = kretprobe_table_lock_ptr(hash); | |
404 | spin_lock_irqsave(hlist_lock, *flags); | |
405 | } | |
406 | ||
407 | void kretprobe_table_lock(unsigned long hash, unsigned long *flags) | |
b94cce92 | 408 | { |
ef53d9c5 S |
409 | spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
410 | spin_lock_irqsave(hlist_lock, *flags); | |
411 | } | |
412 | ||
413 | void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags) | |
414 | { | |
415 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); | |
416 | spinlock_t *hlist_lock; | |
417 | ||
418 | hlist_lock = kretprobe_table_lock_ptr(hash); | |
419 | spin_unlock_irqrestore(hlist_lock, *flags); | |
420 | } | |
421 | ||
422 | void kretprobe_table_unlock(unsigned long hash, unsigned long *flags) | |
423 | { | |
424 | spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); | |
425 | spin_unlock_irqrestore(hlist_lock, *flags); | |
b94cce92 HN |
426 | } |
427 | ||
b94cce92 | 428 | /* |
c6fd91f0 | 429 | * This function is called from finish_task_switch when task tk becomes dead, |
430 | * so that we can recycle any function-return probe instances associated | |
431 | * with this task. These left over instances represent probed functions | |
432 | * that have been called but will never return. | |
b94cce92 | 433 | */ |
d0aaff97 | 434 | void __kprobes kprobe_flush_task(struct task_struct *tk) |
b94cce92 | 435 | { |
62c27be0 | 436 | struct kretprobe_instance *ri; |
99219a3f | 437 | struct hlist_head *head, empty_rp; |
802eae7c | 438 | struct hlist_node *node, *tmp; |
ef53d9c5 | 439 | unsigned long hash, flags = 0; |
802eae7c | 440 | |
ef53d9c5 S |
441 | if (unlikely(!kprobes_initialized)) |
442 | /* Early boot. kretprobe_table_locks not yet initialized. */ | |
443 | return; | |
444 | ||
445 | hash = hash_ptr(tk, KPROBE_HASH_BITS); | |
446 | head = &kretprobe_inst_table[hash]; | |
447 | kretprobe_table_lock(hash, &flags); | |
62c27be0 | 448 | hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { |
449 | if (ri->task == tk) | |
99219a3f | 450 | recycle_rp_inst(ri, &empty_rp); |
62c27be0 | 451 | } |
ef53d9c5 S |
452 | kretprobe_table_unlock(hash, &flags); |
453 | INIT_HLIST_HEAD(&empty_rp); | |
99219a3f | 454 | hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { |
455 | hlist_del(&ri->hlist); | |
456 | kfree(ri); | |
457 | } | |
b94cce92 HN |
458 | } |
459 | ||
b94cce92 HN |
460 | static inline void free_rp_inst(struct kretprobe *rp) |
461 | { | |
462 | struct kretprobe_instance *ri; | |
4c4308cb CH |
463 | struct hlist_node *pos, *next; |
464 | ||
ef53d9c5 S |
465 | hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) { |
466 | hlist_del(&ri->hlist); | |
b94cce92 HN |
467 | kfree(ri); |
468 | } | |
469 | } | |
470 | ||
4a296e07 MH |
471 | static void __kprobes cleanup_rp_inst(struct kretprobe *rp) |
472 | { | |
ef53d9c5 | 473 | unsigned long flags, hash; |
4a296e07 MH |
474 | struct kretprobe_instance *ri; |
475 | struct hlist_node *pos, *next; | |
ef53d9c5 S |
476 | struct hlist_head *head; |
477 | ||
4a296e07 | 478 | /* No race here */ |
ef53d9c5 S |
479 | for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) { |
480 | kretprobe_table_lock(hash, &flags); | |
481 | head = &kretprobe_inst_table[hash]; | |
482 | hlist_for_each_entry_safe(ri, pos, next, head, hlist) { | |
483 | if (ri->rp == rp) | |
484 | ri->rp = NULL; | |
485 | } | |
486 | kretprobe_table_unlock(hash, &flags); | |
4a296e07 | 487 | } |
4a296e07 MH |
488 | free_rp_inst(rp); |
489 | } | |
490 | ||
8b0914ea PP |
491 | /* |
492 | * Keep all fields in the kprobe consistent | |
493 | */ | |
494 | static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p) | |
495 | { | |
496 | memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t)); | |
497 | memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn)); | |
498 | } | |
499 | ||
500 | /* | |
501 | * Add the new probe to old_p->list. Fail if this is the | |
502 | * second jprobe at the address - two jprobes can't coexist | |
503 | */ | |
d0aaff97 | 504 | static int __kprobes add_new_kprobe(struct kprobe *old_p, struct kprobe *p) |
8b0914ea | 505 | { |
8b0914ea | 506 | if (p->break_handler) { |
36721656 | 507 | if (old_p->break_handler) |
508 | return -EEXIST; | |
3516a460 | 509 | list_add_tail_rcu(&p->list, &old_p->list); |
36721656 | 510 | old_p->break_handler = aggr_break_handler; |
8b0914ea | 511 | } else |
3516a460 | 512 | list_add_rcu(&p->list, &old_p->list); |
36721656 | 513 | if (p->post_handler && !old_p->post_handler) |
514 | old_p->post_handler = aggr_post_handler; | |
8b0914ea PP |
515 | return 0; |
516 | } | |
517 | ||
64f562c6 AM |
518 | /* |
519 | * Fill in the required fields of the "manager kprobe". Replace the | |
520 | * earlier kprobe in the hlist with the manager kprobe | |
521 | */ | |
522 | static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p) | |
523 | { | |
8b0914ea | 524 | copy_kprobe(p, ap); |
a9ad965e | 525 | flush_insn_slot(ap); |
64f562c6 | 526 | ap->addr = p->addr; |
64f562c6 | 527 | ap->pre_handler = aggr_pre_handler; |
64f562c6 | 528 | ap->fault_handler = aggr_fault_handler; |
36721656 | 529 | if (p->post_handler) |
530 | ap->post_handler = aggr_post_handler; | |
531 | if (p->break_handler) | |
532 | ap->break_handler = aggr_break_handler; | |
64f562c6 AM |
533 | |
534 | INIT_LIST_HEAD(&ap->list); | |
3516a460 | 535 | list_add_rcu(&p->list, &ap->list); |
64f562c6 | 536 | |
adad0f33 | 537 | hlist_replace_rcu(&p->hlist, &ap->hlist); |
64f562c6 AM |
538 | } |
539 | ||
540 | /* | |
541 | * This is the second or subsequent kprobe at the address - handle | |
542 | * the intricacies | |
64f562c6 | 543 | */ |
d0aaff97 PP |
544 | static int __kprobes register_aggr_kprobe(struct kprobe *old_p, |
545 | struct kprobe *p) | |
64f562c6 AM |
546 | { |
547 | int ret = 0; | |
548 | struct kprobe *ap; | |
549 | ||
8b0914ea PP |
550 | if (old_p->pre_handler == aggr_pre_handler) { |
551 | copy_kprobe(old_p, p); | |
552 | ret = add_new_kprobe(old_p, p); | |
64f562c6 | 553 | } else { |
a0d50069 | 554 | ap = kzalloc(sizeof(struct kprobe), GFP_KERNEL); |
64f562c6 AM |
555 | if (!ap) |
556 | return -ENOMEM; | |
557 | add_aggr_kprobe(ap, old_p); | |
8b0914ea PP |
558 | copy_kprobe(ap, p); |
559 | ret = add_new_kprobe(ap, p); | |
64f562c6 AM |
560 | } |
561 | return ret; | |
562 | } | |
563 | ||
d0aaff97 PP |
564 | static int __kprobes in_kprobes_functions(unsigned long addr) |
565 | { | |
3d8d996e SD |
566 | struct kprobe_blackpoint *kb; |
567 | ||
6f716acd CH |
568 | if (addr >= (unsigned long)__kprobes_text_start && |
569 | addr < (unsigned long)__kprobes_text_end) | |
d0aaff97 | 570 | return -EINVAL; |
3d8d996e SD |
571 | /* |
572 | * If there exists a kprobe_blacklist, verify and | |
573 | * fail any probe registration in the prohibited area | |
574 | */ | |
575 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { | |
576 | if (kb->start_addr) { | |
577 | if (addr >= kb->start_addr && | |
578 | addr < (kb->start_addr + kb->range)) | |
579 | return -EINVAL; | |
580 | } | |
581 | } | |
d0aaff97 PP |
582 | return 0; |
583 | } | |
584 | ||
b2a5cd69 MH |
585 | /* |
586 | * If we have a symbol_name argument, look it up and add the offset field | |
587 | * to it. This way, we can specify a relative address to a symbol. | |
588 | */ | |
589 | static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p) | |
590 | { | |
591 | kprobe_opcode_t *addr = p->addr; | |
592 | if (p->symbol_name) { | |
593 | if (addr) | |
594 | return NULL; | |
595 | kprobe_lookup_name(p->symbol_name, addr); | |
596 | } | |
597 | ||
598 | if (!addr) | |
599 | return NULL; | |
600 | return (kprobe_opcode_t *)(((char *)addr) + p->offset); | |
601 | } | |
602 | ||
df019b1d KA |
603 | static int __kprobes __register_kprobe(struct kprobe *p, |
604 | unsigned long called_from) | |
1da177e4 LT |
605 | { |
606 | int ret = 0; | |
64f562c6 | 607 | struct kprobe *old_p; |
df019b1d | 608 | struct module *probed_mod; |
b2a5cd69 | 609 | kprobe_opcode_t *addr; |
b3e55c72 | 610 | |
b2a5cd69 MH |
611 | addr = kprobe_addr(p); |
612 | if (!addr) | |
3a872d89 | 613 | return -EINVAL; |
b2a5cd69 | 614 | p->addr = addr; |
3a872d89 | 615 | |
6f716acd CH |
616 | if (!kernel_text_address((unsigned long) p->addr) || |
617 | in_kprobes_functions((unsigned long) p->addr)) | |
b3e55c72 MB |
618 | return -EINVAL; |
619 | ||
df019b1d | 620 | p->mod_refcounted = 0; |
6f716acd CH |
621 | |
622 | /* | |
623 | * Check if are we probing a module. | |
624 | */ | |
625 | probed_mod = module_text_address((unsigned long) p->addr); | |
626 | if (probed_mod) { | |
df019b1d | 627 | struct module *calling_mod = module_text_address(called_from); |
6f716acd CH |
628 | /* |
629 | * We must allow modules to probe themself and in this case | |
630 | * avoid incrementing the module refcount, so as to allow | |
631 | * unloading of self probing modules. | |
df019b1d | 632 | */ |
6f716acd | 633 | if (calling_mod && calling_mod != probed_mod) { |
df019b1d KA |
634 | if (unlikely(!try_module_get(probed_mod))) |
635 | return -EINVAL; | |
636 | p->mod_refcounted = 1; | |
637 | } else | |
638 | probed_mod = NULL; | |
639 | } | |
1da177e4 | 640 | |
3516a460 | 641 | p->nmissed = 0; |
9861668f | 642 | INIT_LIST_HEAD(&p->list); |
7a7d1cf9 | 643 | mutex_lock(&kprobe_mutex); |
64f562c6 AM |
644 | old_p = get_kprobe(p->addr); |
645 | if (old_p) { | |
646 | ret = register_aggr_kprobe(old_p, p); | |
1da177e4 LT |
647 | goto out; |
648 | } | |
1da177e4 | 649 | |
6f716acd CH |
650 | ret = arch_prepare_kprobe(p); |
651 | if (ret) | |
49a2a1b8 AK |
652 | goto out; |
653 | ||
64f562c6 | 654 | INIT_HLIST_NODE(&p->hlist); |
3516a460 | 655 | hlist_add_head_rcu(&p->hlist, |
1da177e4 LT |
656 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); |
657 | ||
74a0b576 | 658 | if (kprobe_enabled) |
bf8f6e5b | 659 | arch_arm_kprobe(p); |
74a0b576 | 660 | |
1da177e4 | 661 | out: |
7a7d1cf9 | 662 | mutex_unlock(&kprobe_mutex); |
49a2a1b8 | 663 | |
df019b1d KA |
664 | if (ret && probed_mod) |
665 | module_put(probed_mod); | |
1da177e4 LT |
666 | return ret; |
667 | } | |
668 | ||
9861668f MH |
669 | /* |
670 | * Unregister a kprobe without a scheduler synchronization. | |
671 | */ | |
672 | static int __kprobes __unregister_kprobe_top(struct kprobe *p) | |
1da177e4 | 673 | { |
f709b122 | 674 | struct kprobe *old_p, *list_p; |
64f562c6 | 675 | |
64f562c6 | 676 | old_p = get_kprobe(p->addr); |
9861668f MH |
677 | if (unlikely(!old_p)) |
678 | return -EINVAL; | |
679 | ||
f709b122 KA |
680 | if (p != old_p) { |
681 | list_for_each_entry_rcu(list_p, &old_p->list, list) | |
682 | if (list_p == p) | |
683 | /* kprobe p is a valid probe */ | |
684 | goto valid_p; | |
9861668f | 685 | return -EINVAL; |
f709b122 KA |
686 | } |
687 | valid_p: | |
6f716acd CH |
688 | if (old_p == p || |
689 | (old_p->pre_handler == aggr_pre_handler && | |
9861668f | 690 | list_is_singular(&old_p->list))) { |
bf8f6e5b AM |
691 | /* |
692 | * Only probe on the hash list. Disarm only if kprobes are | |
693 | * enabled - otherwise, the breakpoint would already have | |
694 | * been removed. We save on flushing icache. | |
695 | */ | |
696 | if (kprobe_enabled) | |
697 | arch_disarm_kprobe(p); | |
49a2a1b8 | 698 | hlist_del_rcu(&old_p->hlist); |
49a2a1b8 | 699 | } else { |
9861668f MH |
700 | if (p->break_handler) |
701 | old_p->break_handler = NULL; | |
702 | if (p->post_handler) { | |
703 | list_for_each_entry_rcu(list_p, &old_p->list, list) { | |
704 | if ((list_p != p) && (list_p->post_handler)) | |
705 | goto noclean; | |
706 | } | |
707 | old_p->post_handler = NULL; | |
708 | } | |
709 | noclean: | |
49a2a1b8 | 710 | list_del_rcu(&p->list); |
49a2a1b8 | 711 | } |
9861668f MH |
712 | return 0; |
713 | } | |
3516a460 | 714 | |
9861668f MH |
715 | static void __kprobes __unregister_kprobe_bottom(struct kprobe *p) |
716 | { | |
717 | struct module *mod; | |
718 | struct kprobe *old_p; | |
b3e55c72 | 719 | |
6f716acd CH |
720 | if (p->mod_refcounted) { |
721 | mod = module_text_address((unsigned long)p->addr); | |
722 | if (mod) | |
723 | module_put(mod); | |
724 | } | |
b3e55c72 | 725 | |
9861668f MH |
726 | if (list_empty(&p->list) || list_is_singular(&p->list)) { |
727 | if (!list_empty(&p->list)) { | |
728 | /* "p" is the last child of an aggr_kprobe */ | |
729 | old_p = list_entry(p->list.next, struct kprobe, list); | |
730 | list_del(&p->list); | |
3516a460 | 731 | kfree(old_p); |
49a2a1b8 | 732 | } |
0498b635 | 733 | arch_remove_kprobe(p); |
9861668f MH |
734 | } |
735 | } | |
736 | ||
737 | static int __register_kprobes(struct kprobe **kps, int num, | |
738 | unsigned long called_from) | |
739 | { | |
740 | int i, ret = 0; | |
741 | ||
742 | if (num <= 0) | |
743 | return -EINVAL; | |
744 | for (i = 0; i < num; i++) { | |
745 | ret = __register_kprobe(kps[i], called_from); | |
67dddaad MH |
746 | if (ret < 0) { |
747 | if (i > 0) | |
748 | unregister_kprobes(kps, i); | |
9861668f | 749 | break; |
36721656 | 750 | } |
49a2a1b8 | 751 | } |
9861668f MH |
752 | return ret; |
753 | } | |
754 | ||
755 | /* | |
756 | * Registration and unregistration functions for kprobe. | |
757 | */ | |
758 | int __kprobes register_kprobe(struct kprobe *p) | |
759 | { | |
760 | return __register_kprobes(&p, 1, | |
761 | (unsigned long)__builtin_return_address(0)); | |
762 | } | |
763 | ||
764 | void __kprobes unregister_kprobe(struct kprobe *p) | |
765 | { | |
766 | unregister_kprobes(&p, 1); | |
767 | } | |
768 | ||
769 | int __kprobes register_kprobes(struct kprobe **kps, int num) | |
770 | { | |
771 | return __register_kprobes(kps, num, | |
772 | (unsigned long)__builtin_return_address(0)); | |
773 | } | |
774 | ||
775 | void __kprobes unregister_kprobes(struct kprobe **kps, int num) | |
776 | { | |
777 | int i; | |
778 | ||
779 | if (num <= 0) | |
780 | return; | |
781 | mutex_lock(&kprobe_mutex); | |
782 | for (i = 0; i < num; i++) | |
783 | if (__unregister_kprobe_top(kps[i]) < 0) | |
784 | kps[i]->addr = NULL; | |
785 | mutex_unlock(&kprobe_mutex); | |
786 | ||
787 | synchronize_sched(); | |
788 | for (i = 0; i < num; i++) | |
789 | if (kps[i]->addr) | |
790 | __unregister_kprobe_bottom(kps[i]); | |
1da177e4 LT |
791 | } |
792 | ||
793 | static struct notifier_block kprobe_exceptions_nb = { | |
3d5631e0 AK |
794 | .notifier_call = kprobe_exceptions_notify, |
795 | .priority = 0x7fffffff /* we need to be notified first */ | |
796 | }; | |
797 | ||
3d7e3382 ME |
798 | unsigned long __weak arch_deref_entry_point(void *entry) |
799 | { | |
800 | return (unsigned long)entry; | |
801 | } | |
1da177e4 | 802 | |
26b31c19 MH |
803 | static int __register_jprobes(struct jprobe **jps, int num, |
804 | unsigned long called_from) | |
1da177e4 | 805 | { |
26b31c19 MH |
806 | struct jprobe *jp; |
807 | int ret = 0, i; | |
3d7e3382 | 808 | |
26b31c19 | 809 | if (num <= 0) |
3d7e3382 | 810 | return -EINVAL; |
26b31c19 MH |
811 | for (i = 0; i < num; i++) { |
812 | unsigned long addr; | |
813 | jp = jps[i]; | |
814 | addr = arch_deref_entry_point(jp->entry); | |
815 | ||
816 | if (!kernel_text_address(addr)) | |
817 | ret = -EINVAL; | |
818 | else { | |
819 | /* Todo: Verify probepoint is a function entry point */ | |
820 | jp->kp.pre_handler = setjmp_pre_handler; | |
821 | jp->kp.break_handler = longjmp_break_handler; | |
822 | ret = __register_kprobe(&jp->kp, called_from); | |
823 | } | |
67dddaad MH |
824 | if (ret < 0) { |
825 | if (i > 0) | |
826 | unregister_jprobes(jps, i); | |
26b31c19 MH |
827 | break; |
828 | } | |
829 | } | |
830 | return ret; | |
831 | } | |
3d7e3382 | 832 | |
26b31c19 MH |
833 | int __kprobes register_jprobe(struct jprobe *jp) |
834 | { | |
835 | return __register_jprobes(&jp, 1, | |
df019b1d | 836 | (unsigned long)__builtin_return_address(0)); |
1da177e4 LT |
837 | } |
838 | ||
d0aaff97 | 839 | void __kprobes unregister_jprobe(struct jprobe *jp) |
1da177e4 | 840 | { |
26b31c19 MH |
841 | unregister_jprobes(&jp, 1); |
842 | } | |
843 | ||
844 | int __kprobes register_jprobes(struct jprobe **jps, int num) | |
845 | { | |
846 | return __register_jprobes(jps, num, | |
847 | (unsigned long)__builtin_return_address(0)); | |
848 | } | |
849 | ||
850 | void __kprobes unregister_jprobes(struct jprobe **jps, int num) | |
851 | { | |
852 | int i; | |
853 | ||
854 | if (num <= 0) | |
855 | return; | |
856 | mutex_lock(&kprobe_mutex); | |
857 | for (i = 0; i < num; i++) | |
858 | if (__unregister_kprobe_top(&jps[i]->kp) < 0) | |
859 | jps[i]->kp.addr = NULL; | |
860 | mutex_unlock(&kprobe_mutex); | |
861 | ||
862 | synchronize_sched(); | |
863 | for (i = 0; i < num; i++) { | |
864 | if (jps[i]->kp.addr) | |
865 | __unregister_kprobe_bottom(&jps[i]->kp); | |
866 | } | |
1da177e4 LT |
867 | } |
868 | ||
9edddaa2 | 869 | #ifdef CONFIG_KRETPROBES |
e65cefe8 AB |
870 | /* |
871 | * This kprobe pre_handler is registered with every kretprobe. When probe | |
872 | * hits it will set up the return probe. | |
873 | */ | |
874 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, | |
875 | struct pt_regs *regs) | |
876 | { | |
877 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); | |
ef53d9c5 S |
878 | unsigned long hash, flags = 0; |
879 | struct kretprobe_instance *ri; | |
e65cefe8 AB |
880 | |
881 | /*TODO: consider to only swap the RA after the last pre_handler fired */ | |
ef53d9c5 S |
882 | hash = hash_ptr(current, KPROBE_HASH_BITS); |
883 | spin_lock_irqsave(&rp->lock, flags); | |
4c4308cb | 884 | if (!hlist_empty(&rp->free_instances)) { |
4c4308cb | 885 | ri = hlist_entry(rp->free_instances.first, |
ef53d9c5 S |
886 | struct kretprobe_instance, hlist); |
887 | hlist_del(&ri->hlist); | |
888 | spin_unlock_irqrestore(&rp->lock, flags); | |
889 | ||
4c4308cb CH |
890 | ri->rp = rp; |
891 | ri->task = current; | |
f47cd9b5 AS |
892 | |
893 | if (rp->entry_handler && rp->entry_handler(ri, regs)) { | |
ef53d9c5 | 894 | spin_unlock_irqrestore(&rp->lock, flags); |
f47cd9b5 AS |
895 | return 0; |
896 | } | |
897 | ||
4c4308cb CH |
898 | arch_prepare_kretprobe(ri, regs); |
899 | ||
900 | /* XXX(hch): why is there no hlist_move_head? */ | |
ef53d9c5 S |
901 | INIT_HLIST_NODE(&ri->hlist); |
902 | kretprobe_table_lock(hash, &flags); | |
903 | hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]); | |
904 | kretprobe_table_unlock(hash, &flags); | |
905 | } else { | |
4c4308cb | 906 | rp->nmissed++; |
ef53d9c5 S |
907 | spin_unlock_irqrestore(&rp->lock, flags); |
908 | } | |
e65cefe8 AB |
909 | return 0; |
910 | } | |
911 | ||
4a296e07 MH |
912 | static int __kprobes __register_kretprobe(struct kretprobe *rp, |
913 | unsigned long called_from) | |
b94cce92 HN |
914 | { |
915 | int ret = 0; | |
916 | struct kretprobe_instance *inst; | |
917 | int i; | |
b2a5cd69 | 918 | void *addr; |
f438d914 MH |
919 | |
920 | if (kretprobe_blacklist_size) { | |
b2a5cd69 MH |
921 | addr = kprobe_addr(&rp->kp); |
922 | if (!addr) | |
923 | return -EINVAL; | |
f438d914 MH |
924 | |
925 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
926 | if (kretprobe_blacklist[i].addr == addr) | |
927 | return -EINVAL; | |
928 | } | |
929 | } | |
b94cce92 HN |
930 | |
931 | rp->kp.pre_handler = pre_handler_kretprobe; | |
7522a842 AM |
932 | rp->kp.post_handler = NULL; |
933 | rp->kp.fault_handler = NULL; | |
934 | rp->kp.break_handler = NULL; | |
b94cce92 HN |
935 | |
936 | /* Pre-allocate memory for max kretprobe instances */ | |
937 | if (rp->maxactive <= 0) { | |
938 | #ifdef CONFIG_PREEMPT | |
939 | rp->maxactive = max(10, 2 * NR_CPUS); | |
940 | #else | |
941 | rp->maxactive = NR_CPUS; | |
942 | #endif | |
943 | } | |
ef53d9c5 | 944 | spin_lock_init(&rp->lock); |
b94cce92 HN |
945 | INIT_HLIST_HEAD(&rp->free_instances); |
946 | for (i = 0; i < rp->maxactive; i++) { | |
f47cd9b5 AS |
947 | inst = kmalloc(sizeof(struct kretprobe_instance) + |
948 | rp->data_size, GFP_KERNEL); | |
b94cce92 HN |
949 | if (inst == NULL) { |
950 | free_rp_inst(rp); | |
951 | return -ENOMEM; | |
952 | } | |
ef53d9c5 S |
953 | INIT_HLIST_NODE(&inst->hlist); |
954 | hlist_add_head(&inst->hlist, &rp->free_instances); | |
b94cce92 HN |
955 | } |
956 | ||
957 | rp->nmissed = 0; | |
958 | /* Establish function entry probe point */ | |
4a296e07 MH |
959 | ret = __register_kprobe(&rp->kp, called_from); |
960 | if (ret != 0) | |
b94cce92 HN |
961 | free_rp_inst(rp); |
962 | return ret; | |
963 | } | |
964 | ||
4a296e07 MH |
965 | static int __register_kretprobes(struct kretprobe **rps, int num, |
966 | unsigned long called_from) | |
967 | { | |
968 | int ret = 0, i; | |
969 | ||
970 | if (num <= 0) | |
971 | return -EINVAL; | |
972 | for (i = 0; i < num; i++) { | |
973 | ret = __register_kretprobe(rps[i], called_from); | |
67dddaad MH |
974 | if (ret < 0) { |
975 | if (i > 0) | |
976 | unregister_kretprobes(rps, i); | |
4a296e07 MH |
977 | break; |
978 | } | |
979 | } | |
980 | return ret; | |
981 | } | |
982 | ||
983 | int __kprobes register_kretprobe(struct kretprobe *rp) | |
984 | { | |
985 | return __register_kretprobes(&rp, 1, | |
986 | (unsigned long)__builtin_return_address(0)); | |
987 | } | |
988 | ||
989 | void __kprobes unregister_kretprobe(struct kretprobe *rp) | |
990 | { | |
991 | unregister_kretprobes(&rp, 1); | |
992 | } | |
993 | ||
994 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) | |
995 | { | |
996 | return __register_kretprobes(rps, num, | |
997 | (unsigned long)__builtin_return_address(0)); | |
998 | } | |
999 | ||
1000 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) | |
1001 | { | |
1002 | int i; | |
1003 | ||
1004 | if (num <= 0) | |
1005 | return; | |
1006 | mutex_lock(&kprobe_mutex); | |
1007 | for (i = 0; i < num; i++) | |
1008 | if (__unregister_kprobe_top(&rps[i]->kp) < 0) | |
1009 | rps[i]->kp.addr = NULL; | |
1010 | mutex_unlock(&kprobe_mutex); | |
1011 | ||
1012 | synchronize_sched(); | |
1013 | for (i = 0; i < num; i++) { | |
1014 | if (rps[i]->kp.addr) { | |
1015 | __unregister_kprobe_bottom(&rps[i]->kp); | |
1016 | cleanup_rp_inst(rps[i]); | |
1017 | } | |
1018 | } | |
1019 | } | |
1020 | ||
9edddaa2 | 1021 | #else /* CONFIG_KRETPROBES */ |
d0aaff97 | 1022 | int __kprobes register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
1023 | { |
1024 | return -ENOSYS; | |
1025 | } | |
1026 | ||
4a296e07 | 1027 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) |
346fd59b | 1028 | { |
4a296e07 | 1029 | return -ENOSYS; |
346fd59b | 1030 | } |
d0aaff97 | 1031 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
b94cce92 | 1032 | { |
4a296e07 | 1033 | } |
b94cce92 | 1034 | |
4a296e07 MH |
1035 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) |
1036 | { | |
1037 | } | |
4c4308cb | 1038 | |
4a296e07 MH |
1039 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, |
1040 | struct pt_regs *regs) | |
1041 | { | |
1042 | return 0; | |
b94cce92 HN |
1043 | } |
1044 | ||
4a296e07 MH |
1045 | #endif /* CONFIG_KRETPROBES */ |
1046 | ||
1da177e4 LT |
1047 | static int __init init_kprobes(void) |
1048 | { | |
1049 | int i, err = 0; | |
3d8d996e SD |
1050 | unsigned long offset = 0, size = 0; |
1051 | char *modname, namebuf[128]; | |
1052 | const char *symbol_name; | |
1053 | void *addr; | |
1054 | struct kprobe_blackpoint *kb; | |
1da177e4 LT |
1055 | |
1056 | /* FIXME allocate the probe table, currently defined statically */ | |
1057 | /* initialize all list heads */ | |
b94cce92 | 1058 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1da177e4 | 1059 | INIT_HLIST_HEAD(&kprobe_table[i]); |
b94cce92 | 1060 | INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
ef53d9c5 | 1061 | spin_lock_init(&(kretprobe_table_locks[i].lock)); |
b94cce92 | 1062 | } |
1da177e4 | 1063 | |
3d8d996e SD |
1064 | /* |
1065 | * Lookup and populate the kprobe_blacklist. | |
1066 | * | |
1067 | * Unlike the kretprobe blacklist, we'll need to determine | |
1068 | * the range of addresses that belong to the said functions, | |
1069 | * since a kprobe need not necessarily be at the beginning | |
1070 | * of a function. | |
1071 | */ | |
1072 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { | |
1073 | kprobe_lookup_name(kb->name, addr); | |
1074 | if (!addr) | |
1075 | continue; | |
1076 | ||
1077 | kb->start_addr = (unsigned long)addr; | |
1078 | symbol_name = kallsyms_lookup(kb->start_addr, | |
1079 | &size, &offset, &modname, namebuf); | |
1080 | if (!symbol_name) | |
1081 | kb->range = 0; | |
1082 | else | |
1083 | kb->range = size; | |
1084 | } | |
1085 | ||
f438d914 MH |
1086 | if (kretprobe_blacklist_size) { |
1087 | /* lookup the function address from its name */ | |
1088 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
1089 | kprobe_lookup_name(kretprobe_blacklist[i].name, | |
1090 | kretprobe_blacklist[i].addr); | |
1091 | if (!kretprobe_blacklist[i].addr) | |
1092 | printk("kretprobe: lookup failed: %s\n", | |
1093 | kretprobe_blacklist[i].name); | |
1094 | } | |
1095 | } | |
1096 | ||
bf8f6e5b AM |
1097 | /* By default, kprobes are enabled */ |
1098 | kprobe_enabled = true; | |
1099 | ||
6772926b | 1100 | err = arch_init_kprobes(); |
802eae7c RL |
1101 | if (!err) |
1102 | err = register_die_notifier(&kprobe_exceptions_nb); | |
ef53d9c5 | 1103 | kprobes_initialized = (err == 0); |
802eae7c | 1104 | |
8c1c9356 AM |
1105 | if (!err) |
1106 | init_test_probes(); | |
1da177e4 LT |
1107 | return err; |
1108 | } | |
1109 | ||
346fd59b SD |
1110 | #ifdef CONFIG_DEBUG_FS |
1111 | static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p, | |
bf8f6e5b | 1112 | const char *sym, int offset,char *modname) |
346fd59b SD |
1113 | { |
1114 | char *kprobe_type; | |
1115 | ||
1116 | if (p->pre_handler == pre_handler_kretprobe) | |
1117 | kprobe_type = "r"; | |
1118 | else if (p->pre_handler == setjmp_pre_handler) | |
1119 | kprobe_type = "j"; | |
1120 | else | |
1121 | kprobe_type = "k"; | |
1122 | if (sym) | |
1123 | seq_printf(pi, "%p %s %s+0x%x %s\n", p->addr, kprobe_type, | |
1124 | sym, offset, (modname ? modname : " ")); | |
1125 | else | |
1126 | seq_printf(pi, "%p %s %p\n", p->addr, kprobe_type, p->addr); | |
1127 | } | |
1128 | ||
1129 | static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos) | |
1130 | { | |
1131 | return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; | |
1132 | } | |
1133 | ||
1134 | static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) | |
1135 | { | |
1136 | (*pos)++; | |
1137 | if (*pos >= KPROBE_TABLE_SIZE) | |
1138 | return NULL; | |
1139 | return pos; | |
1140 | } | |
1141 | ||
1142 | static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v) | |
1143 | { | |
1144 | /* Nothing to do */ | |
1145 | } | |
1146 | ||
1147 | static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v) | |
1148 | { | |
1149 | struct hlist_head *head; | |
1150 | struct hlist_node *node; | |
1151 | struct kprobe *p, *kp; | |
1152 | const char *sym = NULL; | |
1153 | unsigned int i = *(loff_t *) v; | |
ffb45122 | 1154 | unsigned long offset = 0; |
346fd59b SD |
1155 | char *modname, namebuf[128]; |
1156 | ||
1157 | head = &kprobe_table[i]; | |
1158 | preempt_disable(); | |
1159 | hlist_for_each_entry_rcu(p, node, head, hlist) { | |
ffb45122 | 1160 | sym = kallsyms_lookup((unsigned long)p->addr, NULL, |
346fd59b SD |
1161 | &offset, &modname, namebuf); |
1162 | if (p->pre_handler == aggr_pre_handler) { | |
1163 | list_for_each_entry_rcu(kp, &p->list, list) | |
1164 | report_probe(pi, kp, sym, offset, modname); | |
1165 | } else | |
1166 | report_probe(pi, p, sym, offset, modname); | |
1167 | } | |
1168 | preempt_enable(); | |
1169 | return 0; | |
1170 | } | |
1171 | ||
1172 | static struct seq_operations kprobes_seq_ops = { | |
1173 | .start = kprobe_seq_start, | |
1174 | .next = kprobe_seq_next, | |
1175 | .stop = kprobe_seq_stop, | |
1176 | .show = show_kprobe_addr | |
1177 | }; | |
1178 | ||
1179 | static int __kprobes kprobes_open(struct inode *inode, struct file *filp) | |
1180 | { | |
1181 | return seq_open(filp, &kprobes_seq_ops); | |
1182 | } | |
1183 | ||
1184 | static struct file_operations debugfs_kprobes_operations = { | |
1185 | .open = kprobes_open, | |
1186 | .read = seq_read, | |
1187 | .llseek = seq_lseek, | |
1188 | .release = seq_release, | |
1189 | }; | |
1190 | ||
bf8f6e5b AM |
1191 | static void __kprobes enable_all_kprobes(void) |
1192 | { | |
1193 | struct hlist_head *head; | |
1194 | struct hlist_node *node; | |
1195 | struct kprobe *p; | |
1196 | unsigned int i; | |
1197 | ||
1198 | mutex_lock(&kprobe_mutex); | |
1199 | ||
1200 | /* If kprobes are already enabled, just return */ | |
1201 | if (kprobe_enabled) | |
1202 | goto already_enabled; | |
1203 | ||
bf8f6e5b AM |
1204 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1205 | head = &kprobe_table[i]; | |
1206 | hlist_for_each_entry_rcu(p, node, head, hlist) | |
1207 | arch_arm_kprobe(p); | |
1208 | } | |
1209 | ||
1210 | kprobe_enabled = true; | |
1211 | printk(KERN_INFO "Kprobes globally enabled\n"); | |
1212 | ||
1213 | already_enabled: | |
1214 | mutex_unlock(&kprobe_mutex); | |
1215 | return; | |
1216 | } | |
1217 | ||
1218 | static void __kprobes disable_all_kprobes(void) | |
1219 | { | |
1220 | struct hlist_head *head; | |
1221 | struct hlist_node *node; | |
1222 | struct kprobe *p; | |
1223 | unsigned int i; | |
1224 | ||
1225 | mutex_lock(&kprobe_mutex); | |
1226 | ||
1227 | /* If kprobes are already disabled, just return */ | |
1228 | if (!kprobe_enabled) | |
1229 | goto already_disabled; | |
1230 | ||
1231 | kprobe_enabled = false; | |
1232 | printk(KERN_INFO "Kprobes globally disabled\n"); | |
1233 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { | |
1234 | head = &kprobe_table[i]; | |
1235 | hlist_for_each_entry_rcu(p, node, head, hlist) { | |
1236 | if (!arch_trampoline_kprobe(p)) | |
1237 | arch_disarm_kprobe(p); | |
1238 | } | |
1239 | } | |
1240 | ||
1241 | mutex_unlock(&kprobe_mutex); | |
1242 | /* Allow all currently running kprobes to complete */ | |
1243 | synchronize_sched(); | |
74a0b576 | 1244 | return; |
bf8f6e5b AM |
1245 | |
1246 | already_disabled: | |
1247 | mutex_unlock(&kprobe_mutex); | |
1248 | return; | |
1249 | } | |
1250 | ||
1251 | /* | |
1252 | * XXX: The debugfs bool file interface doesn't allow for callbacks | |
1253 | * when the bool state is switched. We can reuse that facility when | |
1254 | * available | |
1255 | */ | |
1256 | static ssize_t read_enabled_file_bool(struct file *file, | |
1257 | char __user *user_buf, size_t count, loff_t *ppos) | |
1258 | { | |
1259 | char buf[3]; | |
1260 | ||
1261 | if (kprobe_enabled) | |
1262 | buf[0] = '1'; | |
1263 | else | |
1264 | buf[0] = '0'; | |
1265 | buf[1] = '\n'; | |
1266 | buf[2] = 0x00; | |
1267 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); | |
1268 | } | |
1269 | ||
1270 | static ssize_t write_enabled_file_bool(struct file *file, | |
1271 | const char __user *user_buf, size_t count, loff_t *ppos) | |
1272 | { | |
1273 | char buf[32]; | |
1274 | int buf_size; | |
1275 | ||
1276 | buf_size = min(count, (sizeof(buf)-1)); | |
1277 | if (copy_from_user(buf, user_buf, buf_size)) | |
1278 | return -EFAULT; | |
1279 | ||
1280 | switch (buf[0]) { | |
1281 | case 'y': | |
1282 | case 'Y': | |
1283 | case '1': | |
1284 | enable_all_kprobes(); | |
1285 | break; | |
1286 | case 'n': | |
1287 | case 'N': | |
1288 | case '0': | |
1289 | disable_all_kprobes(); | |
1290 | break; | |
1291 | } | |
1292 | ||
1293 | return count; | |
1294 | } | |
1295 | ||
1296 | static struct file_operations fops_kp = { | |
1297 | .read = read_enabled_file_bool, | |
1298 | .write = write_enabled_file_bool, | |
1299 | }; | |
1300 | ||
346fd59b SD |
1301 | static int __kprobes debugfs_kprobe_init(void) |
1302 | { | |
1303 | struct dentry *dir, *file; | |
bf8f6e5b | 1304 | unsigned int value = 1; |
346fd59b SD |
1305 | |
1306 | dir = debugfs_create_dir("kprobes", NULL); | |
1307 | if (!dir) | |
1308 | return -ENOMEM; | |
1309 | ||
e3869792 | 1310 | file = debugfs_create_file("list", 0444, dir, NULL, |
346fd59b SD |
1311 | &debugfs_kprobes_operations); |
1312 | if (!file) { | |
1313 | debugfs_remove(dir); | |
1314 | return -ENOMEM; | |
1315 | } | |
1316 | ||
bf8f6e5b AM |
1317 | file = debugfs_create_file("enabled", 0600, dir, |
1318 | &value, &fops_kp); | |
1319 | if (!file) { | |
1320 | debugfs_remove(dir); | |
1321 | return -ENOMEM; | |
1322 | } | |
1323 | ||
346fd59b SD |
1324 | return 0; |
1325 | } | |
1326 | ||
1327 | late_initcall(debugfs_kprobe_init); | |
1328 | #endif /* CONFIG_DEBUG_FS */ | |
1329 | ||
1330 | module_init(init_kprobes); | |
1da177e4 LT |
1331 | |
1332 | EXPORT_SYMBOL_GPL(register_kprobe); | |
1333 | EXPORT_SYMBOL_GPL(unregister_kprobe); | |
9861668f MH |
1334 | EXPORT_SYMBOL_GPL(register_kprobes); |
1335 | EXPORT_SYMBOL_GPL(unregister_kprobes); | |
1da177e4 LT |
1336 | EXPORT_SYMBOL_GPL(register_jprobe); |
1337 | EXPORT_SYMBOL_GPL(unregister_jprobe); | |
26b31c19 MH |
1338 | EXPORT_SYMBOL_GPL(register_jprobes); |
1339 | EXPORT_SYMBOL_GPL(unregister_jprobes); | |
1da177e4 | 1340 | EXPORT_SYMBOL_GPL(jprobe_return); |
b94cce92 HN |
1341 | EXPORT_SYMBOL_GPL(register_kretprobe); |
1342 | EXPORT_SYMBOL_GPL(unregister_kretprobe); | |
4a296e07 MH |
1343 | EXPORT_SYMBOL_GPL(register_kretprobes); |
1344 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |