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> | |
b2be84df | 45 | #include <linux/sysctl.h> |
1eeb66a1 | 46 | #include <linux/kdebug.h> |
4460fdad | 47 | #include <linux/memory.h> |
4554dbcb | 48 | #include <linux/ftrace.h> |
afd66255 | 49 | #include <linux/cpu.h> |
bf5438fc | 50 | #include <linux/jump_label.h> |
bf8f6e5b | 51 | |
d0aaff97 | 52 | #include <asm-generic/sections.h> |
1da177e4 LT |
53 | #include <asm/cacheflush.h> |
54 | #include <asm/errno.h> | |
bf8f6e5b | 55 | #include <asm/uaccess.h> |
1da177e4 LT |
56 | |
57 | #define KPROBE_HASH_BITS 6 | |
58 | #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS) | |
59 | ||
3a872d89 AM |
60 | |
61 | /* | |
62 | * Some oddball architectures like 64bit powerpc have function descriptors | |
63 | * so this must be overridable. | |
64 | */ | |
65 | #ifndef kprobe_lookup_name | |
66 | #define kprobe_lookup_name(name, addr) \ | |
67 | addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name))) | |
68 | #endif | |
69 | ||
ef53d9c5 | 70 | static int kprobes_initialized; |
1da177e4 | 71 | static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; |
b94cce92 | 72 | static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; |
1da177e4 | 73 | |
bf8f6e5b | 74 | /* NOTE: change this value only with kprobe_mutex held */ |
e579abeb | 75 | static bool kprobes_all_disarmed; |
bf8f6e5b | 76 | |
43948f50 MH |
77 | /* This protects kprobe_table and optimizing_list */ |
78 | static DEFINE_MUTEX(kprobe_mutex); | |
e6584523 | 79 | static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; |
ef53d9c5 | 80 | static struct { |
7e036d04 | 81 | spinlock_t lock ____cacheline_aligned_in_smp; |
ef53d9c5 S |
82 | } kretprobe_table_locks[KPROBE_TABLE_SIZE]; |
83 | ||
84 | static spinlock_t *kretprobe_table_lock_ptr(unsigned long hash) | |
85 | { | |
86 | return &(kretprobe_table_locks[hash].lock); | |
87 | } | |
1da177e4 | 88 | |
3d8d996e SD |
89 | /* |
90 | * Normally, functions that we'd want to prohibit kprobes in, are marked | |
91 | * __kprobes. But, there are cases where such functions already belong to | |
92 | * a different section (__sched for preempt_schedule) | |
93 | * | |
94 | * For such cases, we now have a blacklist | |
95 | */ | |
544304b2 | 96 | static struct kprobe_blackpoint kprobe_blacklist[] = { |
3d8d996e | 97 | {"preempt_schedule",}, |
65e234ec | 98 | {"native_get_debugreg",}, |
a00e817f MH |
99 | {"irq_entries_start",}, |
100 | {"common_interrupt",}, | |
5ecaafdb | 101 | {"mcount",}, /* mcount can be called from everywhere */ |
3d8d996e SD |
102 | {NULL} /* Terminator */ |
103 | }; | |
104 | ||
2d14e39d | 105 | #ifdef __ARCH_WANT_KPROBES_INSN_SLOT |
9ec4b1f3 AM |
106 | /* |
107 | * kprobe->ainsn.insn points to the copy of the instruction to be | |
108 | * single-stepped. x86_64, POWER4 and above have no-exec support and | |
109 | * stepping on the instruction on a vmalloced/kmalloced/data page | |
110 | * is a recipe for disaster | |
111 | */ | |
9ec4b1f3 | 112 | struct kprobe_insn_page { |
c5cb5a2d | 113 | struct list_head list; |
9ec4b1f3 | 114 | kprobe_opcode_t *insns; /* Page of instruction slots */ |
9ec4b1f3 | 115 | int nused; |
b4c6c34a | 116 | int ngarbage; |
4610ee1d | 117 | char slot_used[]; |
9ec4b1f3 AM |
118 | }; |
119 | ||
4610ee1d MH |
120 | #define KPROBE_INSN_PAGE_SIZE(slots) \ |
121 | (offsetof(struct kprobe_insn_page, slot_used) + \ | |
122 | (sizeof(char) * (slots))) | |
123 | ||
124 | struct kprobe_insn_cache { | |
125 | struct list_head pages; /* list of kprobe_insn_page */ | |
126 | size_t insn_size; /* size of instruction slot */ | |
127 | int nr_garbage; | |
128 | }; | |
129 | ||
130 | static int slots_per_page(struct kprobe_insn_cache *c) | |
131 | { | |
132 | return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t)); | |
133 | } | |
134 | ||
ab40c5c6 MH |
135 | enum kprobe_slot_state { |
136 | SLOT_CLEAN = 0, | |
137 | SLOT_DIRTY = 1, | |
138 | SLOT_USED = 2, | |
139 | }; | |
140 | ||
4610ee1d MH |
141 | static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_slots */ |
142 | static struct kprobe_insn_cache kprobe_insn_slots = { | |
143 | .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages), | |
144 | .insn_size = MAX_INSN_SIZE, | |
145 | .nr_garbage = 0, | |
146 | }; | |
147 | static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c); | |
b4c6c34a | 148 | |
9ec4b1f3 | 149 | /** |
12941560 | 150 | * __get_insn_slot() - Find a slot on an executable page for an instruction. |
9ec4b1f3 AM |
151 | * We allocate an executable page if there's no room on existing ones. |
152 | */ | |
4610ee1d | 153 | static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c) |
9ec4b1f3 AM |
154 | { |
155 | struct kprobe_insn_page *kip; | |
9ec4b1f3 | 156 | |
6f716acd | 157 | retry: |
4610ee1d MH |
158 | list_for_each_entry(kip, &c->pages, list) { |
159 | if (kip->nused < slots_per_page(c)) { | |
9ec4b1f3 | 160 | int i; |
4610ee1d | 161 | for (i = 0; i < slots_per_page(c); i++) { |
ab40c5c6 MH |
162 | if (kip->slot_used[i] == SLOT_CLEAN) { |
163 | kip->slot_used[i] = SLOT_USED; | |
9ec4b1f3 | 164 | kip->nused++; |
4610ee1d | 165 | return kip->insns + (i * c->insn_size); |
9ec4b1f3 AM |
166 | } |
167 | } | |
4610ee1d MH |
168 | /* kip->nused is broken. Fix it. */ |
169 | kip->nused = slots_per_page(c); | |
170 | WARN_ON(1); | |
9ec4b1f3 AM |
171 | } |
172 | } | |
173 | ||
b4c6c34a | 174 | /* If there are any garbage slots, collect it and try again. */ |
4610ee1d | 175 | if (c->nr_garbage && collect_garbage_slots(c) == 0) |
b4c6c34a | 176 | goto retry; |
4610ee1d MH |
177 | |
178 | /* All out of space. Need to allocate a new page. */ | |
179 | kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL); | |
6f716acd | 180 | if (!kip) |
9ec4b1f3 | 181 | return NULL; |
9ec4b1f3 AM |
182 | |
183 | /* | |
184 | * Use module_alloc so this page is within +/- 2GB of where the | |
185 | * kernel image and loaded module images reside. This is required | |
186 | * so x86_64 can correctly handle the %rip-relative fixups. | |
187 | */ | |
188 | kip->insns = module_alloc(PAGE_SIZE); | |
189 | if (!kip->insns) { | |
190 | kfree(kip); | |
191 | return NULL; | |
192 | } | |
c5cb5a2d | 193 | INIT_LIST_HEAD(&kip->list); |
4610ee1d | 194 | memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c)); |
ab40c5c6 | 195 | kip->slot_used[0] = SLOT_USED; |
9ec4b1f3 | 196 | kip->nused = 1; |
b4c6c34a | 197 | kip->ngarbage = 0; |
4610ee1d | 198 | list_add(&kip->list, &c->pages); |
9ec4b1f3 AM |
199 | return kip->insns; |
200 | } | |
201 | ||
4610ee1d | 202 | |
12941560 MH |
203 | kprobe_opcode_t __kprobes *get_insn_slot(void) |
204 | { | |
4610ee1d MH |
205 | kprobe_opcode_t *ret = NULL; |
206 | ||
12941560 | 207 | mutex_lock(&kprobe_insn_mutex); |
4610ee1d | 208 | ret = __get_insn_slot(&kprobe_insn_slots); |
12941560 | 209 | mutex_unlock(&kprobe_insn_mutex); |
4610ee1d | 210 | |
12941560 MH |
211 | return ret; |
212 | } | |
213 | ||
b4c6c34a MH |
214 | /* Return 1 if all garbages are collected, otherwise 0. */ |
215 | static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx) | |
216 | { | |
ab40c5c6 | 217 | kip->slot_used[idx] = SLOT_CLEAN; |
b4c6c34a MH |
218 | kip->nused--; |
219 | if (kip->nused == 0) { | |
220 | /* | |
221 | * Page is no longer in use. Free it unless | |
222 | * it's the last one. We keep the last one | |
223 | * so as not to have to set it up again the | |
224 | * next time somebody inserts a probe. | |
225 | */ | |
4610ee1d | 226 | if (!list_is_singular(&kip->list)) { |
c5cb5a2d | 227 | list_del(&kip->list); |
b4c6c34a MH |
228 | module_free(NULL, kip->insns); |
229 | kfree(kip); | |
230 | } | |
231 | return 1; | |
232 | } | |
233 | return 0; | |
234 | } | |
235 | ||
4610ee1d | 236 | static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c) |
b4c6c34a | 237 | { |
c5cb5a2d | 238 | struct kprobe_insn_page *kip, *next; |
b4c6c34a | 239 | |
615d0ebb MH |
240 | /* Ensure no-one is interrupted on the garbages */ |
241 | synchronize_sched(); | |
b4c6c34a | 242 | |
4610ee1d | 243 | list_for_each_entry_safe(kip, next, &c->pages, list) { |
b4c6c34a | 244 | int i; |
b4c6c34a MH |
245 | if (kip->ngarbage == 0) |
246 | continue; | |
247 | kip->ngarbage = 0; /* we will collect all garbages */ | |
4610ee1d | 248 | for (i = 0; i < slots_per_page(c); i++) { |
ab40c5c6 | 249 | if (kip->slot_used[i] == SLOT_DIRTY && |
b4c6c34a MH |
250 | collect_one_slot(kip, i)) |
251 | break; | |
252 | } | |
253 | } | |
4610ee1d | 254 | c->nr_garbage = 0; |
b4c6c34a MH |
255 | return 0; |
256 | } | |
257 | ||
4610ee1d MH |
258 | static void __kprobes __free_insn_slot(struct kprobe_insn_cache *c, |
259 | kprobe_opcode_t *slot, int dirty) | |
9ec4b1f3 AM |
260 | { |
261 | struct kprobe_insn_page *kip; | |
9ec4b1f3 | 262 | |
4610ee1d | 263 | list_for_each_entry(kip, &c->pages, list) { |
83ff56f4 MH |
264 | long idx = ((long)slot - (long)kip->insns) / |
265 | (c->insn_size * sizeof(kprobe_opcode_t)); | |
4610ee1d MH |
266 | if (idx >= 0 && idx < slots_per_page(c)) { |
267 | WARN_ON(kip->slot_used[idx] != SLOT_USED); | |
b4c6c34a | 268 | if (dirty) { |
4610ee1d | 269 | kip->slot_used[idx] = SLOT_DIRTY; |
b4c6c34a | 270 | kip->ngarbage++; |
4610ee1d MH |
271 | if (++c->nr_garbage > slots_per_page(c)) |
272 | collect_garbage_slots(c); | |
c5cb5a2d | 273 | } else |
4610ee1d MH |
274 | collect_one_slot(kip, idx); |
275 | return; | |
9ec4b1f3 AM |
276 | } |
277 | } | |
4610ee1d MH |
278 | /* Could not free this slot. */ |
279 | WARN_ON(1); | |
280 | } | |
6f716acd | 281 | |
4610ee1d MH |
282 | void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty) |
283 | { | |
284 | mutex_lock(&kprobe_insn_mutex); | |
285 | __free_insn_slot(&kprobe_insn_slots, slot, dirty); | |
12941560 | 286 | mutex_unlock(&kprobe_insn_mutex); |
9ec4b1f3 | 287 | } |
afd66255 MH |
288 | #ifdef CONFIG_OPTPROBES |
289 | /* For optimized_kprobe buffer */ | |
290 | static DEFINE_MUTEX(kprobe_optinsn_mutex); /* Protects kprobe_optinsn_slots */ | |
291 | static struct kprobe_insn_cache kprobe_optinsn_slots = { | |
292 | .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages), | |
293 | /* .insn_size is initialized later */ | |
294 | .nr_garbage = 0, | |
295 | }; | |
296 | /* Get a slot for optimized_kprobe buffer */ | |
297 | kprobe_opcode_t __kprobes *get_optinsn_slot(void) | |
298 | { | |
299 | kprobe_opcode_t *ret = NULL; | |
300 | ||
301 | mutex_lock(&kprobe_optinsn_mutex); | |
302 | ret = __get_insn_slot(&kprobe_optinsn_slots); | |
303 | mutex_unlock(&kprobe_optinsn_mutex); | |
304 | ||
305 | return ret; | |
306 | } | |
307 | ||
308 | void __kprobes free_optinsn_slot(kprobe_opcode_t * slot, int dirty) | |
309 | { | |
310 | mutex_lock(&kprobe_optinsn_mutex); | |
311 | __free_insn_slot(&kprobe_optinsn_slots, slot, dirty); | |
312 | mutex_unlock(&kprobe_optinsn_mutex); | |
313 | } | |
314 | #endif | |
2d14e39d | 315 | #endif |
9ec4b1f3 | 316 | |
e6584523 AM |
317 | /* We have preemption disabled.. so it is safe to use __ versions */ |
318 | static inline void set_kprobe_instance(struct kprobe *kp) | |
319 | { | |
320 | __get_cpu_var(kprobe_instance) = kp; | |
321 | } | |
322 | ||
323 | static inline void reset_kprobe_instance(void) | |
324 | { | |
325 | __get_cpu_var(kprobe_instance) = NULL; | |
326 | } | |
327 | ||
3516a460 AM |
328 | /* |
329 | * This routine is called either: | |
49a2a1b8 | 330 | * - under the kprobe_mutex - during kprobe_[un]register() |
3516a460 | 331 | * OR |
d217d545 | 332 | * - with preemption disabled - from arch/xxx/kernel/kprobes.c |
3516a460 | 333 | */ |
d0aaff97 | 334 | struct kprobe __kprobes *get_kprobe(void *addr) |
1da177e4 LT |
335 | { |
336 | struct hlist_head *head; | |
337 | struct hlist_node *node; | |
3516a460 | 338 | struct kprobe *p; |
1da177e4 LT |
339 | |
340 | head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; | |
3516a460 | 341 | hlist_for_each_entry_rcu(p, node, head, hlist) { |
1da177e4 LT |
342 | if (p->addr == addr) |
343 | return p; | |
344 | } | |
afd66255 | 345 | |
1da177e4 LT |
346 | return NULL; |
347 | } | |
348 | ||
afd66255 MH |
349 | static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs); |
350 | ||
351 | /* Return true if the kprobe is an aggregator */ | |
352 | static inline int kprobe_aggrprobe(struct kprobe *p) | |
353 | { | |
354 | return p->pre_handler == aggr_pre_handler; | |
355 | } | |
356 | ||
357 | /* | |
358 | * Keep all fields in the kprobe consistent | |
359 | */ | |
6d8e40a8 | 360 | static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p) |
afd66255 | 361 | { |
6d8e40a8 MH |
362 | memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t)); |
363 | memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn)); | |
afd66255 MH |
364 | } |
365 | ||
366 | #ifdef CONFIG_OPTPROBES | |
b2be84df MH |
367 | /* NOTE: change this value only with kprobe_mutex held */ |
368 | static bool kprobes_allow_optimization; | |
369 | ||
afd66255 MH |
370 | /* |
371 | * Call all pre_handler on the list, but ignores its return value. | |
372 | * This must be called from arch-dep optimized caller. | |
373 | */ | |
374 | void __kprobes opt_pre_handler(struct kprobe *p, struct pt_regs *regs) | |
375 | { | |
376 | struct kprobe *kp; | |
377 | ||
378 | list_for_each_entry_rcu(kp, &p->list, list) { | |
379 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { | |
380 | set_kprobe_instance(kp); | |
381 | kp->pre_handler(kp, regs); | |
382 | } | |
383 | reset_kprobe_instance(); | |
384 | } | |
385 | } | |
386 | ||
387 | /* Return true(!0) if the kprobe is ready for optimization. */ | |
388 | static inline int kprobe_optready(struct kprobe *p) | |
389 | { | |
390 | struct optimized_kprobe *op; | |
391 | ||
392 | if (kprobe_aggrprobe(p)) { | |
393 | op = container_of(p, struct optimized_kprobe, kp); | |
394 | return arch_prepared_optinsn(&op->optinsn); | |
395 | } | |
396 | ||
397 | return 0; | |
398 | } | |
399 | ||
400 | /* | |
401 | * Return an optimized kprobe whose optimizing code replaces | |
402 | * instructions including addr (exclude breakpoint). | |
403 | */ | |
6376b229 | 404 | static struct kprobe *__kprobes get_optimized_kprobe(unsigned long addr) |
afd66255 MH |
405 | { |
406 | int i; | |
407 | struct kprobe *p = NULL; | |
408 | struct optimized_kprobe *op; | |
409 | ||
410 | /* Don't check i == 0, since that is a breakpoint case. */ | |
411 | for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++) | |
412 | p = get_kprobe((void *)(addr - i)); | |
413 | ||
414 | if (p && kprobe_optready(p)) { | |
415 | op = container_of(p, struct optimized_kprobe, kp); | |
416 | if (arch_within_optimized_kprobe(op, addr)) | |
417 | return p; | |
418 | } | |
419 | ||
420 | return NULL; | |
421 | } | |
422 | ||
423 | /* Optimization staging list, protected by kprobe_mutex */ | |
424 | static LIST_HEAD(optimizing_list); | |
425 | ||
426 | static void kprobe_optimizer(struct work_struct *work); | |
427 | static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer); | |
428 | #define OPTIMIZE_DELAY 5 | |
429 | ||
61f4e13f MH |
430 | /* |
431 | * Optimize (replace a breakpoint with a jump) kprobes listed on | |
432 | * optimizing_list. | |
433 | */ | |
434 | static __kprobes void do_optimize_kprobes(void) | |
afd66255 MH |
435 | { |
436 | struct optimized_kprobe *op, *tmp; | |
437 | ||
afd66255 MH |
438 | /* |
439 | * The optimization/unoptimization refers online_cpus via | |
440 | * stop_machine() and cpu-hotplug modifies online_cpus. | |
441 | * And same time, text_mutex will be held in cpu-hotplug and here. | |
442 | * This combination can cause a deadlock (cpu-hotplug try to lock | |
443 | * text_mutex but stop_machine can not be done because online_cpus | |
444 | * has been changed) | |
445 | * To avoid this deadlock, we need to call get_online_cpus() | |
446 | * for preventing cpu-hotplug outside of text_mutex locking. | |
447 | */ | |
448 | get_online_cpus(); | |
449 | mutex_lock(&text_mutex); | |
450 | list_for_each_entry_safe(op, tmp, &optimizing_list, list) { | |
451 | WARN_ON(kprobe_disabled(&op->kp)); | |
452 | if (arch_optimize_kprobe(op) < 0) | |
453 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; | |
454 | list_del_init(&op->list); | |
455 | } | |
456 | mutex_unlock(&text_mutex); | |
457 | put_online_cpus(); | |
61f4e13f MH |
458 | } |
459 | ||
460 | /* Kprobe jump optimizer */ | |
461 | static __kprobes void kprobe_optimizer(struct work_struct *work) | |
462 | { | |
463 | /* Lock modules while optimizing kprobes */ | |
464 | mutex_lock(&module_mutex); | |
465 | mutex_lock(&kprobe_mutex); | |
466 | if (kprobes_all_disarmed || !kprobes_allow_optimization) | |
467 | goto end; | |
468 | ||
469 | /* | |
470 | * Wait for quiesence period to ensure all running interrupts | |
471 | * are done. Because optprobe may modify multiple instructions | |
472 | * there is a chance that Nth instruction is interrupted. In that | |
473 | * case, running interrupt can return to 2nd-Nth byte of jump | |
474 | * instruction. This wait is for avoiding it. | |
475 | */ | |
476 | synchronize_sched(); | |
477 | ||
478 | do_optimize_kprobes(); | |
afd66255 MH |
479 | end: |
480 | mutex_unlock(&kprobe_mutex); | |
481 | mutex_unlock(&module_mutex); | |
482 | } | |
483 | ||
484 | /* Optimize kprobe if p is ready to be optimized */ | |
485 | static __kprobes void optimize_kprobe(struct kprobe *p) | |
486 | { | |
487 | struct optimized_kprobe *op; | |
488 | ||
489 | /* Check if the kprobe is disabled or not ready for optimization. */ | |
b2be84df | 490 | if (!kprobe_optready(p) || !kprobes_allow_optimization || |
afd66255 MH |
491 | (kprobe_disabled(p) || kprobes_all_disarmed)) |
492 | return; | |
493 | ||
494 | /* Both of break_handler and post_handler are not supported. */ | |
495 | if (p->break_handler || p->post_handler) | |
496 | return; | |
497 | ||
498 | op = container_of(p, struct optimized_kprobe, kp); | |
499 | ||
500 | /* Check there is no other kprobes at the optimized instructions */ | |
501 | if (arch_check_optimized_kprobe(op) < 0) | |
502 | return; | |
503 | ||
504 | /* Check if it is already optimized. */ | |
505 | if (op->kp.flags & KPROBE_FLAG_OPTIMIZED) | |
506 | return; | |
507 | ||
508 | op->kp.flags |= KPROBE_FLAG_OPTIMIZED; | |
509 | list_add(&op->list, &optimizing_list); | |
510 | if (!delayed_work_pending(&optimizing_work)) | |
511 | schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY); | |
512 | } | |
513 | ||
514 | /* Unoptimize a kprobe if p is optimized */ | |
515 | static __kprobes void unoptimize_kprobe(struct kprobe *p) | |
516 | { | |
517 | struct optimized_kprobe *op; | |
518 | ||
519 | if ((p->flags & KPROBE_FLAG_OPTIMIZED) && kprobe_aggrprobe(p)) { | |
520 | op = container_of(p, struct optimized_kprobe, kp); | |
521 | if (!list_empty(&op->list)) | |
522 | /* Dequeue from the optimization queue */ | |
523 | list_del_init(&op->list); | |
524 | else | |
525 | /* Replace jump with break */ | |
526 | arch_unoptimize_kprobe(op); | |
527 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; | |
528 | } | |
529 | } | |
530 | ||
531 | /* Remove optimized instructions */ | |
532 | static void __kprobes kill_optimized_kprobe(struct kprobe *p) | |
533 | { | |
534 | struct optimized_kprobe *op; | |
535 | ||
536 | op = container_of(p, struct optimized_kprobe, kp); | |
537 | if (!list_empty(&op->list)) { | |
538 | /* Dequeue from the optimization queue */ | |
539 | list_del_init(&op->list); | |
540 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; | |
541 | } | |
542 | /* Don't unoptimize, because the target code will be freed. */ | |
543 | arch_remove_optimized_kprobe(op); | |
544 | } | |
545 | ||
546 | /* Try to prepare optimized instructions */ | |
547 | static __kprobes void prepare_optimized_kprobe(struct kprobe *p) | |
548 | { | |
549 | struct optimized_kprobe *op; | |
550 | ||
551 | op = container_of(p, struct optimized_kprobe, kp); | |
552 | arch_prepare_optimized_kprobe(op); | |
553 | } | |
554 | ||
555 | /* Free optimized instructions and optimized_kprobe */ | |
556 | static __kprobes void free_aggr_kprobe(struct kprobe *p) | |
557 | { | |
558 | struct optimized_kprobe *op; | |
559 | ||
560 | op = container_of(p, struct optimized_kprobe, kp); | |
561 | arch_remove_optimized_kprobe(op); | |
562 | kfree(op); | |
563 | } | |
564 | ||
565 | /* Allocate new optimized_kprobe and try to prepare optimized instructions */ | |
566 | static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p) | |
567 | { | |
568 | struct optimized_kprobe *op; | |
569 | ||
570 | op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL); | |
571 | if (!op) | |
572 | return NULL; | |
573 | ||
574 | INIT_LIST_HEAD(&op->list); | |
575 | op->kp.addr = p->addr; | |
576 | arch_prepare_optimized_kprobe(op); | |
577 | ||
578 | return &op->kp; | |
579 | } | |
580 | ||
581 | static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p); | |
582 | ||
583 | /* | |
584 | * Prepare an optimized_kprobe and optimize it | |
585 | * NOTE: p must be a normal registered kprobe | |
586 | */ | |
587 | static __kprobes void try_to_optimize_kprobe(struct kprobe *p) | |
588 | { | |
589 | struct kprobe *ap; | |
590 | struct optimized_kprobe *op; | |
591 | ||
592 | ap = alloc_aggr_kprobe(p); | |
593 | if (!ap) | |
594 | return; | |
595 | ||
596 | op = container_of(ap, struct optimized_kprobe, kp); | |
597 | if (!arch_prepared_optinsn(&op->optinsn)) { | |
598 | /* If failed to setup optimizing, fallback to kprobe */ | |
599 | free_aggr_kprobe(ap); | |
600 | return; | |
601 | } | |
602 | ||
603 | init_aggr_kprobe(ap, p); | |
604 | optimize_kprobe(ap); | |
605 | } | |
606 | ||
b2be84df | 607 | #ifdef CONFIG_SYSCTL |
43948f50 | 608 | /* This should be called with kprobe_mutex locked */ |
b2be84df MH |
609 | static void __kprobes optimize_all_kprobes(void) |
610 | { | |
611 | struct hlist_head *head; | |
612 | struct hlist_node *node; | |
613 | struct kprobe *p; | |
614 | unsigned int i; | |
615 | ||
616 | /* If optimization is already allowed, just return */ | |
617 | if (kprobes_allow_optimization) | |
618 | return; | |
619 | ||
620 | kprobes_allow_optimization = true; | |
b2be84df MH |
621 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
622 | head = &kprobe_table[i]; | |
623 | hlist_for_each_entry_rcu(p, node, head, hlist) | |
624 | if (!kprobe_disabled(p)) | |
625 | optimize_kprobe(p); | |
626 | } | |
b2be84df MH |
627 | printk(KERN_INFO "Kprobes globally optimized\n"); |
628 | } | |
629 | ||
43948f50 | 630 | /* This should be called with kprobe_mutex locked */ |
b2be84df MH |
631 | static void __kprobes unoptimize_all_kprobes(void) |
632 | { | |
633 | struct hlist_head *head; | |
634 | struct hlist_node *node; | |
635 | struct kprobe *p; | |
636 | unsigned int i; | |
637 | ||
638 | /* If optimization is already prohibited, just return */ | |
639 | if (!kprobes_allow_optimization) | |
640 | return; | |
641 | ||
642 | kprobes_allow_optimization = false; | |
643 | printk(KERN_INFO "Kprobes globally unoptimized\n"); | |
644 | get_online_cpus(); /* For avoiding text_mutex deadlock */ | |
645 | mutex_lock(&text_mutex); | |
646 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { | |
647 | head = &kprobe_table[i]; | |
648 | hlist_for_each_entry_rcu(p, node, head, hlist) { | |
649 | if (!kprobe_disabled(p)) | |
650 | unoptimize_kprobe(p); | |
651 | } | |
652 | } | |
653 | ||
654 | mutex_unlock(&text_mutex); | |
655 | put_online_cpus(); | |
656 | /* Allow all currently running kprobes to complete */ | |
657 | synchronize_sched(); | |
658 | } | |
659 | ||
660 | int sysctl_kprobes_optimization; | |
661 | int proc_kprobes_optimization_handler(struct ctl_table *table, int write, | |
662 | void __user *buffer, size_t *length, | |
663 | loff_t *ppos) | |
664 | { | |
665 | int ret; | |
666 | ||
667 | mutex_lock(&kprobe_mutex); | |
668 | sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0; | |
669 | ret = proc_dointvec_minmax(table, write, buffer, length, ppos); | |
670 | ||
671 | if (sysctl_kprobes_optimization) | |
672 | optimize_all_kprobes(); | |
673 | else | |
674 | unoptimize_all_kprobes(); | |
675 | mutex_unlock(&kprobe_mutex); | |
676 | ||
677 | return ret; | |
678 | } | |
679 | #endif /* CONFIG_SYSCTL */ | |
680 | ||
afd66255 MH |
681 | static void __kprobes __arm_kprobe(struct kprobe *p) |
682 | { | |
6d8e40a8 | 683 | struct kprobe *_p; |
afd66255 MH |
684 | |
685 | /* Check collision with other optimized kprobes */ | |
6d8e40a8 MH |
686 | _p = get_optimized_kprobe((unsigned long)p->addr); |
687 | if (unlikely(_p)) | |
688 | unoptimize_kprobe(_p); /* Fallback to unoptimized kprobe */ | |
afd66255 MH |
689 | |
690 | arch_arm_kprobe(p); | |
691 | optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */ | |
692 | } | |
693 | ||
694 | static void __kprobes __disarm_kprobe(struct kprobe *p) | |
695 | { | |
6d8e40a8 | 696 | struct kprobe *_p; |
afd66255 MH |
697 | |
698 | unoptimize_kprobe(p); /* Try to unoptimize */ | |
699 | arch_disarm_kprobe(p); | |
700 | ||
701 | /* If another kprobe was blocked, optimize it. */ | |
6d8e40a8 MH |
702 | _p = get_optimized_kprobe((unsigned long)p->addr); |
703 | if (unlikely(_p)) | |
704 | optimize_kprobe(_p); | |
afd66255 MH |
705 | } |
706 | ||
707 | #else /* !CONFIG_OPTPROBES */ | |
708 | ||
709 | #define optimize_kprobe(p) do {} while (0) | |
710 | #define unoptimize_kprobe(p) do {} while (0) | |
711 | #define kill_optimized_kprobe(p) do {} while (0) | |
712 | #define prepare_optimized_kprobe(p) do {} while (0) | |
713 | #define try_to_optimize_kprobe(p) do {} while (0) | |
714 | #define __arm_kprobe(p) arch_arm_kprobe(p) | |
715 | #define __disarm_kprobe(p) arch_disarm_kprobe(p) | |
716 | ||
717 | static __kprobes void free_aggr_kprobe(struct kprobe *p) | |
718 | { | |
719 | kfree(p); | |
720 | } | |
721 | ||
722 | static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p) | |
723 | { | |
724 | return kzalloc(sizeof(struct kprobe), GFP_KERNEL); | |
725 | } | |
726 | #endif /* CONFIG_OPTPROBES */ | |
727 | ||
201517a7 MH |
728 | /* Arm a kprobe with text_mutex */ |
729 | static void __kprobes arm_kprobe(struct kprobe *kp) | |
730 | { | |
afd66255 MH |
731 | /* |
732 | * Here, since __arm_kprobe() doesn't use stop_machine(), | |
733 | * this doesn't cause deadlock on text_mutex. So, we don't | |
734 | * need get_online_cpus(). | |
735 | */ | |
201517a7 | 736 | mutex_lock(&text_mutex); |
afd66255 | 737 | __arm_kprobe(kp); |
201517a7 MH |
738 | mutex_unlock(&text_mutex); |
739 | } | |
740 | ||
741 | /* Disarm a kprobe with text_mutex */ | |
742 | static void __kprobes disarm_kprobe(struct kprobe *kp) | |
743 | { | |
afd66255 | 744 | get_online_cpus(); /* For avoiding text_mutex deadlock */ |
201517a7 | 745 | mutex_lock(&text_mutex); |
afd66255 | 746 | __disarm_kprobe(kp); |
201517a7 | 747 | mutex_unlock(&text_mutex); |
afd66255 | 748 | put_online_cpus(); |
201517a7 MH |
749 | } |
750 | ||
64f562c6 AM |
751 | /* |
752 | * Aggregate handlers for multiple kprobes support - these handlers | |
753 | * take care of invoking the individual kprobe handlers on p->list | |
754 | */ | |
d0aaff97 | 755 | static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
64f562c6 AM |
756 | { |
757 | struct kprobe *kp; | |
758 | ||
3516a460 | 759 | list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d | 760 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
e6584523 | 761 | set_kprobe_instance(kp); |
8b0914ea PP |
762 | if (kp->pre_handler(kp, regs)) |
763 | return 1; | |
64f562c6 | 764 | } |
e6584523 | 765 | reset_kprobe_instance(); |
64f562c6 AM |
766 | } |
767 | return 0; | |
768 | } | |
769 | ||
d0aaff97 PP |
770 | static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
771 | unsigned long flags) | |
64f562c6 AM |
772 | { |
773 | struct kprobe *kp; | |
774 | ||
3516a460 | 775 | list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d | 776 | if (kp->post_handler && likely(!kprobe_disabled(kp))) { |
e6584523 | 777 | set_kprobe_instance(kp); |
64f562c6 | 778 | kp->post_handler(kp, regs, flags); |
e6584523 | 779 | reset_kprobe_instance(); |
64f562c6 AM |
780 | } |
781 | } | |
64f562c6 AM |
782 | } |
783 | ||
d0aaff97 PP |
784 | static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, |
785 | int trapnr) | |
64f562c6 | 786 | { |
e6584523 AM |
787 | struct kprobe *cur = __get_cpu_var(kprobe_instance); |
788 | ||
64f562c6 AM |
789 | /* |
790 | * if we faulted "during" the execution of a user specified | |
791 | * probe handler, invoke just that probe's fault handler | |
792 | */ | |
e6584523 AM |
793 | if (cur && cur->fault_handler) { |
794 | if (cur->fault_handler(cur, regs, trapnr)) | |
64f562c6 AM |
795 | return 1; |
796 | } | |
797 | return 0; | |
798 | } | |
799 | ||
d0aaff97 | 800 | static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs) |
8b0914ea | 801 | { |
e6584523 AM |
802 | struct kprobe *cur = __get_cpu_var(kprobe_instance); |
803 | int ret = 0; | |
804 | ||
805 | if (cur && cur->break_handler) { | |
806 | if (cur->break_handler(cur, regs)) | |
807 | ret = 1; | |
8b0914ea | 808 | } |
e6584523 AM |
809 | reset_kprobe_instance(); |
810 | return ret; | |
8b0914ea PP |
811 | } |
812 | ||
bf8d5c52 KA |
813 | /* Walks the list and increments nmissed count for multiprobe case */ |
814 | void __kprobes kprobes_inc_nmissed_count(struct kprobe *p) | |
815 | { | |
816 | struct kprobe *kp; | |
afd66255 | 817 | if (!kprobe_aggrprobe(p)) { |
bf8d5c52 KA |
818 | p->nmissed++; |
819 | } else { | |
820 | list_for_each_entry_rcu(kp, &p->list, list) | |
821 | kp->nmissed++; | |
822 | } | |
823 | return; | |
824 | } | |
825 | ||
99219a3f | 826 | void __kprobes recycle_rp_inst(struct kretprobe_instance *ri, |
827 | struct hlist_head *head) | |
b94cce92 | 828 | { |
ef53d9c5 S |
829 | struct kretprobe *rp = ri->rp; |
830 | ||
b94cce92 HN |
831 | /* remove rp inst off the rprobe_inst_table */ |
832 | hlist_del(&ri->hlist); | |
ef53d9c5 S |
833 | INIT_HLIST_NODE(&ri->hlist); |
834 | if (likely(rp)) { | |
835 | spin_lock(&rp->lock); | |
836 | hlist_add_head(&ri->hlist, &rp->free_instances); | |
837 | spin_unlock(&rp->lock); | |
b94cce92 HN |
838 | } else |
839 | /* Unregistering */ | |
99219a3f | 840 | hlist_add_head(&ri->hlist, head); |
b94cce92 HN |
841 | } |
842 | ||
017c39bd | 843 | void __kprobes kretprobe_hash_lock(struct task_struct *tsk, |
ef53d9c5 | 844 | struct hlist_head **head, unsigned long *flags) |
635c17c2 | 845 | __acquires(hlist_lock) |
ef53d9c5 S |
846 | { |
847 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); | |
848 | spinlock_t *hlist_lock; | |
849 | ||
850 | *head = &kretprobe_inst_table[hash]; | |
851 | hlist_lock = kretprobe_table_lock_ptr(hash); | |
852 | spin_lock_irqsave(hlist_lock, *flags); | |
853 | } | |
854 | ||
017c39bd MH |
855 | static void __kprobes kretprobe_table_lock(unsigned long hash, |
856 | unsigned long *flags) | |
635c17c2 | 857 | __acquires(hlist_lock) |
b94cce92 | 858 | { |
ef53d9c5 S |
859 | spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
860 | spin_lock_irqsave(hlist_lock, *flags); | |
861 | } | |
862 | ||
017c39bd MH |
863 | void __kprobes kretprobe_hash_unlock(struct task_struct *tsk, |
864 | unsigned long *flags) | |
635c17c2 | 865 | __releases(hlist_lock) |
ef53d9c5 S |
866 | { |
867 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); | |
868 | spinlock_t *hlist_lock; | |
869 | ||
870 | hlist_lock = kretprobe_table_lock_ptr(hash); | |
871 | spin_unlock_irqrestore(hlist_lock, *flags); | |
872 | } | |
873 | ||
6376b229 NK |
874 | static void __kprobes kretprobe_table_unlock(unsigned long hash, |
875 | unsigned long *flags) | |
635c17c2 | 876 | __releases(hlist_lock) |
ef53d9c5 S |
877 | { |
878 | spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); | |
879 | spin_unlock_irqrestore(hlist_lock, *flags); | |
b94cce92 HN |
880 | } |
881 | ||
b94cce92 | 882 | /* |
c6fd91f0 | 883 | * This function is called from finish_task_switch when task tk becomes dead, |
884 | * so that we can recycle any function-return probe instances associated | |
885 | * with this task. These left over instances represent probed functions | |
886 | * that have been called but will never return. | |
b94cce92 | 887 | */ |
d0aaff97 | 888 | void __kprobes kprobe_flush_task(struct task_struct *tk) |
b94cce92 | 889 | { |
62c27be0 | 890 | struct kretprobe_instance *ri; |
99219a3f | 891 | struct hlist_head *head, empty_rp; |
802eae7c | 892 | struct hlist_node *node, *tmp; |
ef53d9c5 | 893 | unsigned long hash, flags = 0; |
802eae7c | 894 | |
ef53d9c5 S |
895 | if (unlikely(!kprobes_initialized)) |
896 | /* Early boot. kretprobe_table_locks not yet initialized. */ | |
897 | return; | |
898 | ||
899 | hash = hash_ptr(tk, KPROBE_HASH_BITS); | |
900 | head = &kretprobe_inst_table[hash]; | |
901 | kretprobe_table_lock(hash, &flags); | |
62c27be0 | 902 | hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { |
903 | if (ri->task == tk) | |
99219a3f | 904 | recycle_rp_inst(ri, &empty_rp); |
62c27be0 | 905 | } |
ef53d9c5 S |
906 | kretprobe_table_unlock(hash, &flags); |
907 | INIT_HLIST_HEAD(&empty_rp); | |
99219a3f | 908 | hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { |
909 | hlist_del(&ri->hlist); | |
910 | kfree(ri); | |
911 | } | |
b94cce92 HN |
912 | } |
913 | ||
b94cce92 HN |
914 | static inline void free_rp_inst(struct kretprobe *rp) |
915 | { | |
916 | struct kretprobe_instance *ri; | |
4c4308cb CH |
917 | struct hlist_node *pos, *next; |
918 | ||
ef53d9c5 S |
919 | hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) { |
920 | hlist_del(&ri->hlist); | |
b94cce92 HN |
921 | kfree(ri); |
922 | } | |
923 | } | |
924 | ||
4a296e07 MH |
925 | static void __kprobes cleanup_rp_inst(struct kretprobe *rp) |
926 | { | |
ef53d9c5 | 927 | unsigned long flags, hash; |
4a296e07 MH |
928 | struct kretprobe_instance *ri; |
929 | struct hlist_node *pos, *next; | |
ef53d9c5 S |
930 | struct hlist_head *head; |
931 | ||
4a296e07 | 932 | /* No race here */ |
ef53d9c5 S |
933 | for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) { |
934 | kretprobe_table_lock(hash, &flags); | |
935 | head = &kretprobe_inst_table[hash]; | |
936 | hlist_for_each_entry_safe(ri, pos, next, head, hlist) { | |
937 | if (ri->rp == rp) | |
938 | ri->rp = NULL; | |
939 | } | |
940 | kretprobe_table_unlock(hash, &flags); | |
4a296e07 | 941 | } |
4a296e07 MH |
942 | free_rp_inst(rp); |
943 | } | |
944 | ||
8b0914ea | 945 | /* |
b918e5e6 | 946 | * Add the new probe to ap->list. Fail if this is the |
8b0914ea PP |
947 | * second jprobe at the address - two jprobes can't coexist |
948 | */ | |
b918e5e6 | 949 | static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p) |
8b0914ea | 950 | { |
de5bd88d | 951 | BUG_ON(kprobe_gone(ap) || kprobe_gone(p)); |
afd66255 MH |
952 | |
953 | if (p->break_handler || p->post_handler) | |
954 | unoptimize_kprobe(ap); /* Fall back to normal kprobe */ | |
955 | ||
8b0914ea | 956 | if (p->break_handler) { |
b918e5e6 | 957 | if (ap->break_handler) |
36721656 | 958 | return -EEXIST; |
b918e5e6 MH |
959 | list_add_tail_rcu(&p->list, &ap->list); |
960 | ap->break_handler = aggr_break_handler; | |
8b0914ea | 961 | } else |
b918e5e6 MH |
962 | list_add_rcu(&p->list, &ap->list); |
963 | if (p->post_handler && !ap->post_handler) | |
964 | ap->post_handler = aggr_post_handler; | |
de5bd88d MH |
965 | |
966 | if (kprobe_disabled(ap) && !kprobe_disabled(p)) { | |
967 | ap->flags &= ~KPROBE_FLAG_DISABLED; | |
968 | if (!kprobes_all_disarmed) | |
969 | /* Arm the breakpoint again. */ | |
afd66255 | 970 | __arm_kprobe(ap); |
de5bd88d | 971 | } |
8b0914ea PP |
972 | return 0; |
973 | } | |
974 | ||
64f562c6 AM |
975 | /* |
976 | * Fill in the required fields of the "manager kprobe". Replace the | |
977 | * earlier kprobe in the hlist with the manager kprobe | |
978 | */ | |
afd66255 | 979 | static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p) |
64f562c6 | 980 | { |
afd66255 | 981 | /* Copy p's insn slot to ap */ |
8b0914ea | 982 | copy_kprobe(p, ap); |
a9ad965e | 983 | flush_insn_slot(ap); |
64f562c6 | 984 | ap->addr = p->addr; |
afd66255 | 985 | ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED; |
64f562c6 | 986 | ap->pre_handler = aggr_pre_handler; |
64f562c6 | 987 | ap->fault_handler = aggr_fault_handler; |
e8386a0c MH |
988 | /* We don't care the kprobe which has gone. */ |
989 | if (p->post_handler && !kprobe_gone(p)) | |
36721656 | 990 | ap->post_handler = aggr_post_handler; |
e8386a0c | 991 | if (p->break_handler && !kprobe_gone(p)) |
36721656 | 992 | ap->break_handler = aggr_break_handler; |
64f562c6 AM |
993 | |
994 | INIT_LIST_HEAD(&ap->list); | |
afd66255 | 995 | INIT_HLIST_NODE(&ap->hlist); |
64f562c6 | 996 | |
afd66255 | 997 | list_add_rcu(&p->list, &ap->list); |
adad0f33 | 998 | hlist_replace_rcu(&p->hlist, &ap->hlist); |
64f562c6 AM |
999 | } |
1000 | ||
1001 | /* | |
1002 | * This is the second or subsequent kprobe at the address - handle | |
1003 | * the intricacies | |
64f562c6 | 1004 | */ |
6d8e40a8 | 1005 | static int __kprobes register_aggr_kprobe(struct kprobe *orig_p, |
d0aaff97 | 1006 | struct kprobe *p) |
64f562c6 AM |
1007 | { |
1008 | int ret = 0; | |
6d8e40a8 | 1009 | struct kprobe *ap = orig_p; |
64f562c6 | 1010 | |
6d8e40a8 MH |
1011 | if (!kprobe_aggrprobe(orig_p)) { |
1012 | /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */ | |
1013 | ap = alloc_aggr_kprobe(orig_p); | |
b918e5e6 MH |
1014 | if (!ap) |
1015 | return -ENOMEM; | |
6d8e40a8 | 1016 | init_aggr_kprobe(ap, orig_p); |
b918e5e6 MH |
1017 | } |
1018 | ||
1019 | if (kprobe_gone(ap)) { | |
e8386a0c MH |
1020 | /* |
1021 | * Attempting to insert new probe at the same location that | |
1022 | * had a probe in the module vaddr area which already | |
1023 | * freed. So, the instruction slot has already been | |
1024 | * released. We need a new slot for the new probe. | |
1025 | */ | |
b918e5e6 | 1026 | ret = arch_prepare_kprobe(ap); |
e8386a0c | 1027 | if (ret) |
b918e5e6 MH |
1028 | /* |
1029 | * Even if fail to allocate new slot, don't need to | |
1030 | * free aggr_probe. It will be used next time, or | |
1031 | * freed by unregister_kprobe. | |
1032 | */ | |
e8386a0c | 1033 | return ret; |
de5bd88d | 1034 | |
afd66255 MH |
1035 | /* Prepare optimized instructions if possible. */ |
1036 | prepare_optimized_kprobe(ap); | |
1037 | ||
e8386a0c | 1038 | /* |
de5bd88d MH |
1039 | * Clear gone flag to prevent allocating new slot again, and |
1040 | * set disabled flag because it is not armed yet. | |
e8386a0c | 1041 | */ |
de5bd88d MH |
1042 | ap->flags = (ap->flags & ~KPROBE_FLAG_GONE) |
1043 | | KPROBE_FLAG_DISABLED; | |
e8386a0c | 1044 | } |
b918e5e6 | 1045 | |
afd66255 | 1046 | /* Copy ap's insn slot to p */ |
b918e5e6 MH |
1047 | copy_kprobe(ap, p); |
1048 | return add_new_kprobe(ap, p); | |
64f562c6 AM |
1049 | } |
1050 | ||
d0aaff97 PP |
1051 | static int __kprobes in_kprobes_functions(unsigned long addr) |
1052 | { | |
3d8d996e SD |
1053 | struct kprobe_blackpoint *kb; |
1054 | ||
6f716acd CH |
1055 | if (addr >= (unsigned long)__kprobes_text_start && |
1056 | addr < (unsigned long)__kprobes_text_end) | |
d0aaff97 | 1057 | return -EINVAL; |
3d8d996e SD |
1058 | /* |
1059 | * If there exists a kprobe_blacklist, verify and | |
1060 | * fail any probe registration in the prohibited area | |
1061 | */ | |
1062 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { | |
1063 | if (kb->start_addr) { | |
1064 | if (addr >= kb->start_addr && | |
1065 | addr < (kb->start_addr + kb->range)) | |
1066 | return -EINVAL; | |
1067 | } | |
1068 | } | |
d0aaff97 PP |
1069 | return 0; |
1070 | } | |
1071 | ||
b2a5cd69 MH |
1072 | /* |
1073 | * If we have a symbol_name argument, look it up and add the offset field | |
1074 | * to it. This way, we can specify a relative address to a symbol. | |
1075 | */ | |
1076 | static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p) | |
1077 | { | |
1078 | kprobe_opcode_t *addr = p->addr; | |
1079 | if (p->symbol_name) { | |
1080 | if (addr) | |
1081 | return NULL; | |
1082 | kprobe_lookup_name(p->symbol_name, addr); | |
1083 | } | |
1084 | ||
1085 | if (!addr) | |
1086 | return NULL; | |
1087 | return (kprobe_opcode_t *)(((char *)addr) + p->offset); | |
1088 | } | |
1089 | ||
1f0ab409 AM |
1090 | /* Check passed kprobe is valid and return kprobe in kprobe_table. */ |
1091 | static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p) | |
1092 | { | |
6d8e40a8 | 1093 | struct kprobe *ap, *list_p; |
1f0ab409 | 1094 | |
6d8e40a8 MH |
1095 | ap = get_kprobe(p->addr); |
1096 | if (unlikely(!ap)) | |
1f0ab409 AM |
1097 | return NULL; |
1098 | ||
6d8e40a8 MH |
1099 | if (p != ap) { |
1100 | list_for_each_entry_rcu(list_p, &ap->list, list) | |
1f0ab409 AM |
1101 | if (list_p == p) |
1102 | /* kprobe p is a valid probe */ | |
1103 | goto valid; | |
1104 | return NULL; | |
1105 | } | |
1106 | valid: | |
6d8e40a8 | 1107 | return ap; |
1f0ab409 AM |
1108 | } |
1109 | ||
1110 | /* Return error if the kprobe is being re-registered */ | |
1111 | static inline int check_kprobe_rereg(struct kprobe *p) | |
1112 | { | |
1113 | int ret = 0; | |
1f0ab409 AM |
1114 | |
1115 | mutex_lock(&kprobe_mutex); | |
6d8e40a8 | 1116 | if (__get_valid_kprobe(p)) |
1f0ab409 AM |
1117 | ret = -EINVAL; |
1118 | mutex_unlock(&kprobe_mutex); | |
6d8e40a8 | 1119 | |
1f0ab409 AM |
1120 | return ret; |
1121 | } | |
1122 | ||
49ad2fd7 | 1123 | int __kprobes register_kprobe(struct kprobe *p) |
1da177e4 LT |
1124 | { |
1125 | int ret = 0; | |
64f562c6 | 1126 | struct kprobe *old_p; |
df019b1d | 1127 | struct module *probed_mod; |
b2a5cd69 | 1128 | kprobe_opcode_t *addr; |
b3e55c72 | 1129 | |
b2a5cd69 MH |
1130 | addr = kprobe_addr(p); |
1131 | if (!addr) | |
3a872d89 | 1132 | return -EINVAL; |
b2a5cd69 | 1133 | p->addr = addr; |
3a872d89 | 1134 | |
1f0ab409 AM |
1135 | ret = check_kprobe_rereg(p); |
1136 | if (ret) | |
1137 | return ret; | |
1138 | ||
91bad2f8 | 1139 | jump_label_lock(); |
de31c3ca | 1140 | preempt_disable(); |
ec30c5f3 | 1141 | if (!kernel_text_address((unsigned long) p->addr) || |
4554dbcb | 1142 | in_kprobes_functions((unsigned long) p->addr) || |
4c3ef6d7 | 1143 | ftrace_text_reserved(p->addr, p->addr) || |
de31c3ca SR |
1144 | jump_label_text_reserved(p->addr, p->addr)) |
1145 | goto fail_with_jump_label; | |
b3e55c72 | 1146 | |
de5bd88d MH |
1147 | /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */ |
1148 | p->flags &= KPROBE_FLAG_DISABLED; | |
1149 | ||
6f716acd CH |
1150 | /* |
1151 | * Check if are we probing a module. | |
1152 | */ | |
a189d035 | 1153 | probed_mod = __module_text_address((unsigned long) p->addr); |
6f716acd | 1154 | if (probed_mod) { |
6f716acd | 1155 | /* |
e8386a0c MH |
1156 | * We must hold a refcount of the probed module while updating |
1157 | * its code to prohibit unexpected unloading. | |
df019b1d | 1158 | */ |
de31c3ca SR |
1159 | if (unlikely(!try_module_get(probed_mod))) |
1160 | goto fail_with_jump_label; | |
1161 | ||
f24659d9 MH |
1162 | /* |
1163 | * If the module freed .init.text, we couldn't insert | |
1164 | * kprobes in there. | |
1165 | */ | |
1166 | if (within_module_init((unsigned long)p->addr, probed_mod) && | |
1167 | probed_mod->state != MODULE_STATE_COMING) { | |
1168 | module_put(probed_mod); | |
de31c3ca | 1169 | goto fail_with_jump_label; |
f24659d9 | 1170 | } |
df019b1d | 1171 | } |
a189d035 | 1172 | preempt_enable(); |
de31c3ca | 1173 | jump_label_unlock(); |
1da177e4 | 1174 | |
3516a460 | 1175 | p->nmissed = 0; |
9861668f | 1176 | INIT_LIST_HEAD(&p->list); |
7a7d1cf9 | 1177 | mutex_lock(&kprobe_mutex); |
afd66255 | 1178 | |
91bad2f8 JB |
1179 | jump_label_lock(); /* needed to call jump_label_text_reserved() */ |
1180 | ||
afd66255 MH |
1181 | get_online_cpus(); /* For avoiding text_mutex deadlock. */ |
1182 | mutex_lock(&text_mutex); | |
1183 | ||
64f562c6 AM |
1184 | old_p = get_kprobe(p->addr); |
1185 | if (old_p) { | |
afd66255 | 1186 | /* Since this may unoptimize old_p, locking text_mutex. */ |
64f562c6 | 1187 | ret = register_aggr_kprobe(old_p, p); |
1da177e4 LT |
1188 | goto out; |
1189 | } | |
1da177e4 | 1190 | |
6f716acd CH |
1191 | ret = arch_prepare_kprobe(p); |
1192 | if (ret) | |
afd66255 | 1193 | goto out; |
49a2a1b8 | 1194 | |
64f562c6 | 1195 | INIT_HLIST_NODE(&p->hlist); |
3516a460 | 1196 | hlist_add_head_rcu(&p->hlist, |
1da177e4 LT |
1197 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); |
1198 | ||
de5bd88d | 1199 | if (!kprobes_all_disarmed && !kprobe_disabled(p)) |
afd66255 MH |
1200 | __arm_kprobe(p); |
1201 | ||
1202 | /* Try to optimize kprobe */ | |
1203 | try_to_optimize_kprobe(p); | |
74a0b576 | 1204 | |
1da177e4 | 1205 | out: |
afd66255 MH |
1206 | mutex_unlock(&text_mutex); |
1207 | put_online_cpus(); | |
91bad2f8 | 1208 | jump_label_unlock(); |
7a7d1cf9 | 1209 | mutex_unlock(&kprobe_mutex); |
49a2a1b8 | 1210 | |
e8386a0c | 1211 | if (probed_mod) |
df019b1d | 1212 | module_put(probed_mod); |
e8386a0c | 1213 | |
1da177e4 | 1214 | return ret; |
de31c3ca SR |
1215 | |
1216 | fail_with_jump_label: | |
1217 | preempt_enable(); | |
1218 | jump_label_unlock(); | |
1219 | return -EINVAL; | |
1da177e4 | 1220 | } |
99081ab5 | 1221 | EXPORT_SYMBOL_GPL(register_kprobe); |
1da177e4 | 1222 | |
6f0f1dd7 MH |
1223 | /* Check if all probes on the aggrprobe are disabled */ |
1224 | static int __kprobes aggr_kprobe_disabled(struct kprobe *ap) | |
1225 | { | |
1226 | struct kprobe *kp; | |
1227 | ||
1228 | list_for_each_entry_rcu(kp, &ap->list, list) | |
1229 | if (!kprobe_disabled(kp)) | |
1230 | /* | |
1231 | * There is an active probe on the list. | |
1232 | * We can't disable this ap. | |
1233 | */ | |
1234 | return 0; | |
1235 | ||
1236 | return 1; | |
1237 | } | |
1238 | ||
1239 | /* Disable one kprobe: Make sure called under kprobe_mutex is locked */ | |
1240 | static struct kprobe *__kprobes __disable_kprobe(struct kprobe *p) | |
1241 | { | |
1242 | struct kprobe *orig_p; | |
1243 | ||
1244 | /* Get an original kprobe for return */ | |
1245 | orig_p = __get_valid_kprobe(p); | |
1246 | if (unlikely(orig_p == NULL)) | |
1247 | return NULL; | |
1248 | ||
1249 | if (!kprobe_disabled(p)) { | |
1250 | /* Disable probe if it is a child probe */ | |
1251 | if (p != orig_p) | |
1252 | p->flags |= KPROBE_FLAG_DISABLED; | |
1253 | ||
1254 | /* Try to disarm and disable this/parent probe */ | |
1255 | if (p == orig_p || aggr_kprobe_disabled(orig_p)) { | |
1256 | disarm_kprobe(orig_p); | |
1257 | orig_p->flags |= KPROBE_FLAG_DISABLED; | |
1258 | } | |
1259 | } | |
1260 | ||
1261 | return orig_p; | |
1262 | } | |
1263 | ||
de5bd88d MH |
1264 | /* |
1265 | * Unregister a kprobe without a scheduler synchronization. | |
1266 | */ | |
1267 | static int __kprobes __unregister_kprobe_top(struct kprobe *p) | |
1268 | { | |
6d8e40a8 | 1269 | struct kprobe *ap, *list_p; |
de5bd88d | 1270 | |
6f0f1dd7 MH |
1271 | /* Disable kprobe. This will disarm it if needed. */ |
1272 | ap = __disable_kprobe(p); | |
6d8e40a8 | 1273 | if (ap == NULL) |
de5bd88d MH |
1274 | return -EINVAL; |
1275 | ||
6f0f1dd7 | 1276 | if (ap == p) |
bf8f6e5b | 1277 | /* |
6f0f1dd7 MH |
1278 | * This probe is an independent(and non-optimized) kprobe |
1279 | * (not an aggrprobe). Remove from the hash list. | |
bf8f6e5b | 1280 | */ |
6f0f1dd7 MH |
1281 | goto disarmed; |
1282 | ||
1283 | /* Following process expects this probe is an aggrprobe */ | |
1284 | WARN_ON(!kprobe_aggrprobe(ap)); | |
1285 | ||
1286 | if (list_is_singular(&ap->list)) | |
1287 | /* This probe is the last child of aggrprobe */ | |
1288 | goto disarmed; | |
1289 | else { | |
1290 | /* If disabling probe has special handlers, update aggrprobe */ | |
e8386a0c | 1291 | if (p->break_handler && !kprobe_gone(p)) |
6d8e40a8 | 1292 | ap->break_handler = NULL; |
e8386a0c | 1293 | if (p->post_handler && !kprobe_gone(p)) { |
6d8e40a8 | 1294 | list_for_each_entry_rcu(list_p, &ap->list, list) { |
9861668f MH |
1295 | if ((list_p != p) && (list_p->post_handler)) |
1296 | goto noclean; | |
1297 | } | |
6d8e40a8 | 1298 | ap->post_handler = NULL; |
9861668f MH |
1299 | } |
1300 | noclean: | |
6f0f1dd7 MH |
1301 | /* |
1302 | * Remove from the aggrprobe: this path will do nothing in | |
1303 | * __unregister_kprobe_bottom(). | |
1304 | */ | |
49a2a1b8 | 1305 | list_del_rcu(&p->list); |
6f0f1dd7 MH |
1306 | if (!kprobe_disabled(ap) && !kprobes_all_disarmed) |
1307 | /* | |
1308 | * Try to optimize this probe again, because post | |
1309 | * handler may have been changed. | |
1310 | */ | |
1311 | optimize_kprobe(ap); | |
49a2a1b8 | 1312 | } |
9861668f | 1313 | return 0; |
6f0f1dd7 MH |
1314 | |
1315 | disarmed: | |
1316 | hlist_del_rcu(&ap->hlist); | |
1317 | return 0; | |
9861668f | 1318 | } |
3516a460 | 1319 | |
9861668f MH |
1320 | static void __kprobes __unregister_kprobe_bottom(struct kprobe *p) |
1321 | { | |
6d8e40a8 | 1322 | struct kprobe *ap; |
b3e55c72 | 1323 | |
e8386a0c | 1324 | if (list_empty(&p->list)) |
0498b635 | 1325 | arch_remove_kprobe(p); |
e8386a0c MH |
1326 | else if (list_is_singular(&p->list)) { |
1327 | /* "p" is the last child of an aggr_kprobe */ | |
6d8e40a8 | 1328 | ap = list_entry(p->list.next, struct kprobe, list); |
e8386a0c | 1329 | list_del(&p->list); |
6d8e40a8 MH |
1330 | arch_remove_kprobe(ap); |
1331 | free_aggr_kprobe(ap); | |
9861668f MH |
1332 | } |
1333 | } | |
1334 | ||
49ad2fd7 | 1335 | int __kprobes register_kprobes(struct kprobe **kps, int num) |
9861668f MH |
1336 | { |
1337 | int i, ret = 0; | |
1338 | ||
1339 | if (num <= 0) | |
1340 | return -EINVAL; | |
1341 | for (i = 0; i < num; i++) { | |
49ad2fd7 | 1342 | ret = register_kprobe(kps[i]); |
67dddaad MH |
1343 | if (ret < 0) { |
1344 | if (i > 0) | |
1345 | unregister_kprobes(kps, i); | |
9861668f | 1346 | break; |
36721656 | 1347 | } |
49a2a1b8 | 1348 | } |
9861668f MH |
1349 | return ret; |
1350 | } | |
99081ab5 | 1351 | EXPORT_SYMBOL_GPL(register_kprobes); |
9861668f | 1352 | |
9861668f MH |
1353 | void __kprobes unregister_kprobe(struct kprobe *p) |
1354 | { | |
1355 | unregister_kprobes(&p, 1); | |
1356 | } | |
99081ab5 | 1357 | EXPORT_SYMBOL_GPL(unregister_kprobe); |
9861668f | 1358 | |
9861668f MH |
1359 | void __kprobes unregister_kprobes(struct kprobe **kps, int num) |
1360 | { | |
1361 | int i; | |
1362 | ||
1363 | if (num <= 0) | |
1364 | return; | |
1365 | mutex_lock(&kprobe_mutex); | |
1366 | for (i = 0; i < num; i++) | |
1367 | if (__unregister_kprobe_top(kps[i]) < 0) | |
1368 | kps[i]->addr = NULL; | |
1369 | mutex_unlock(&kprobe_mutex); | |
1370 | ||
1371 | synchronize_sched(); | |
1372 | for (i = 0; i < num; i++) | |
1373 | if (kps[i]->addr) | |
1374 | __unregister_kprobe_bottom(kps[i]); | |
1da177e4 | 1375 | } |
99081ab5 | 1376 | EXPORT_SYMBOL_GPL(unregister_kprobes); |
1da177e4 LT |
1377 | |
1378 | static struct notifier_block kprobe_exceptions_nb = { | |
3d5631e0 AK |
1379 | .notifier_call = kprobe_exceptions_notify, |
1380 | .priority = 0x7fffffff /* we need to be notified first */ | |
1381 | }; | |
1382 | ||
3d7e3382 ME |
1383 | unsigned long __weak arch_deref_entry_point(void *entry) |
1384 | { | |
1385 | return (unsigned long)entry; | |
1386 | } | |
1da177e4 | 1387 | |
49ad2fd7 | 1388 | int __kprobes register_jprobes(struct jprobe **jps, int num) |
1da177e4 | 1389 | { |
26b31c19 MH |
1390 | struct jprobe *jp; |
1391 | int ret = 0, i; | |
3d7e3382 | 1392 | |
26b31c19 | 1393 | if (num <= 0) |
3d7e3382 | 1394 | return -EINVAL; |
26b31c19 | 1395 | for (i = 0; i < num; i++) { |
05662bdb | 1396 | unsigned long addr, offset; |
26b31c19 MH |
1397 | jp = jps[i]; |
1398 | addr = arch_deref_entry_point(jp->entry); | |
1399 | ||
05662bdb NK |
1400 | /* Verify probepoint is a function entry point */ |
1401 | if (kallsyms_lookup_size_offset(addr, NULL, &offset) && | |
1402 | offset == 0) { | |
1403 | jp->kp.pre_handler = setjmp_pre_handler; | |
1404 | jp->kp.break_handler = longjmp_break_handler; | |
1405 | ret = register_kprobe(&jp->kp); | |
1406 | } else | |
1407 | ret = -EINVAL; | |
edbaadbe | 1408 | |
67dddaad MH |
1409 | if (ret < 0) { |
1410 | if (i > 0) | |
1411 | unregister_jprobes(jps, i); | |
26b31c19 MH |
1412 | break; |
1413 | } | |
1414 | } | |
1415 | return ret; | |
1416 | } | |
99081ab5 | 1417 | EXPORT_SYMBOL_GPL(register_jprobes); |
3d7e3382 | 1418 | |
26b31c19 MH |
1419 | int __kprobes register_jprobe(struct jprobe *jp) |
1420 | { | |
49ad2fd7 | 1421 | return register_jprobes(&jp, 1); |
1da177e4 | 1422 | } |
99081ab5 | 1423 | EXPORT_SYMBOL_GPL(register_jprobe); |
1da177e4 | 1424 | |
d0aaff97 | 1425 | void __kprobes unregister_jprobe(struct jprobe *jp) |
1da177e4 | 1426 | { |
26b31c19 MH |
1427 | unregister_jprobes(&jp, 1); |
1428 | } | |
99081ab5 | 1429 | EXPORT_SYMBOL_GPL(unregister_jprobe); |
26b31c19 | 1430 | |
26b31c19 MH |
1431 | void __kprobes unregister_jprobes(struct jprobe **jps, int num) |
1432 | { | |
1433 | int i; | |
1434 | ||
1435 | if (num <= 0) | |
1436 | return; | |
1437 | mutex_lock(&kprobe_mutex); | |
1438 | for (i = 0; i < num; i++) | |
1439 | if (__unregister_kprobe_top(&jps[i]->kp) < 0) | |
1440 | jps[i]->kp.addr = NULL; | |
1441 | mutex_unlock(&kprobe_mutex); | |
1442 | ||
1443 | synchronize_sched(); | |
1444 | for (i = 0; i < num; i++) { | |
1445 | if (jps[i]->kp.addr) | |
1446 | __unregister_kprobe_bottom(&jps[i]->kp); | |
1447 | } | |
1da177e4 | 1448 | } |
99081ab5 | 1449 | EXPORT_SYMBOL_GPL(unregister_jprobes); |
1da177e4 | 1450 | |
9edddaa2 | 1451 | #ifdef CONFIG_KRETPROBES |
e65cefe8 AB |
1452 | /* |
1453 | * This kprobe pre_handler is registered with every kretprobe. When probe | |
1454 | * hits it will set up the return probe. | |
1455 | */ | |
1456 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, | |
1457 | struct pt_regs *regs) | |
1458 | { | |
1459 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); | |
ef53d9c5 S |
1460 | unsigned long hash, flags = 0; |
1461 | struct kretprobe_instance *ri; | |
e65cefe8 AB |
1462 | |
1463 | /*TODO: consider to only swap the RA after the last pre_handler fired */ | |
ef53d9c5 S |
1464 | hash = hash_ptr(current, KPROBE_HASH_BITS); |
1465 | spin_lock_irqsave(&rp->lock, flags); | |
4c4308cb | 1466 | if (!hlist_empty(&rp->free_instances)) { |
4c4308cb | 1467 | ri = hlist_entry(rp->free_instances.first, |
ef53d9c5 S |
1468 | struct kretprobe_instance, hlist); |
1469 | hlist_del(&ri->hlist); | |
1470 | spin_unlock_irqrestore(&rp->lock, flags); | |
1471 | ||
4c4308cb CH |
1472 | ri->rp = rp; |
1473 | ri->task = current; | |
f47cd9b5 | 1474 | |
f02b8624 | 1475 | if (rp->entry_handler && rp->entry_handler(ri, regs)) |
f47cd9b5 | 1476 | return 0; |
f47cd9b5 | 1477 | |
4c4308cb CH |
1478 | arch_prepare_kretprobe(ri, regs); |
1479 | ||
1480 | /* XXX(hch): why is there no hlist_move_head? */ | |
ef53d9c5 S |
1481 | INIT_HLIST_NODE(&ri->hlist); |
1482 | kretprobe_table_lock(hash, &flags); | |
1483 | hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]); | |
1484 | kretprobe_table_unlock(hash, &flags); | |
1485 | } else { | |
4c4308cb | 1486 | rp->nmissed++; |
ef53d9c5 S |
1487 | spin_unlock_irqrestore(&rp->lock, flags); |
1488 | } | |
e65cefe8 AB |
1489 | return 0; |
1490 | } | |
1491 | ||
49ad2fd7 | 1492 | int __kprobes register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
1493 | { |
1494 | int ret = 0; | |
1495 | struct kretprobe_instance *inst; | |
1496 | int i; | |
b2a5cd69 | 1497 | void *addr; |
f438d914 MH |
1498 | |
1499 | if (kretprobe_blacklist_size) { | |
b2a5cd69 MH |
1500 | addr = kprobe_addr(&rp->kp); |
1501 | if (!addr) | |
1502 | return -EINVAL; | |
f438d914 MH |
1503 | |
1504 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
1505 | if (kretprobe_blacklist[i].addr == addr) | |
1506 | return -EINVAL; | |
1507 | } | |
1508 | } | |
b94cce92 HN |
1509 | |
1510 | rp->kp.pre_handler = pre_handler_kretprobe; | |
7522a842 AM |
1511 | rp->kp.post_handler = NULL; |
1512 | rp->kp.fault_handler = NULL; | |
1513 | rp->kp.break_handler = NULL; | |
b94cce92 HN |
1514 | |
1515 | /* Pre-allocate memory for max kretprobe instances */ | |
1516 | if (rp->maxactive <= 0) { | |
1517 | #ifdef CONFIG_PREEMPT | |
c2ef6661 | 1518 | rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus()); |
b94cce92 | 1519 | #else |
4dae560f | 1520 | rp->maxactive = num_possible_cpus(); |
b94cce92 HN |
1521 | #endif |
1522 | } | |
ef53d9c5 | 1523 | spin_lock_init(&rp->lock); |
b94cce92 HN |
1524 | INIT_HLIST_HEAD(&rp->free_instances); |
1525 | for (i = 0; i < rp->maxactive; i++) { | |
f47cd9b5 AS |
1526 | inst = kmalloc(sizeof(struct kretprobe_instance) + |
1527 | rp->data_size, GFP_KERNEL); | |
b94cce92 HN |
1528 | if (inst == NULL) { |
1529 | free_rp_inst(rp); | |
1530 | return -ENOMEM; | |
1531 | } | |
ef53d9c5 S |
1532 | INIT_HLIST_NODE(&inst->hlist); |
1533 | hlist_add_head(&inst->hlist, &rp->free_instances); | |
b94cce92 HN |
1534 | } |
1535 | ||
1536 | rp->nmissed = 0; | |
1537 | /* Establish function entry probe point */ | |
49ad2fd7 | 1538 | ret = register_kprobe(&rp->kp); |
4a296e07 | 1539 | if (ret != 0) |
b94cce92 HN |
1540 | free_rp_inst(rp); |
1541 | return ret; | |
1542 | } | |
99081ab5 | 1543 | EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce92 | 1544 | |
49ad2fd7 | 1545 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) |
4a296e07 MH |
1546 | { |
1547 | int ret = 0, i; | |
1548 | ||
1549 | if (num <= 0) | |
1550 | return -EINVAL; | |
1551 | for (i = 0; i < num; i++) { | |
49ad2fd7 | 1552 | ret = register_kretprobe(rps[i]); |
67dddaad MH |
1553 | if (ret < 0) { |
1554 | if (i > 0) | |
1555 | unregister_kretprobes(rps, i); | |
4a296e07 MH |
1556 | break; |
1557 | } | |
1558 | } | |
1559 | return ret; | |
1560 | } | |
99081ab5 | 1561 | EXPORT_SYMBOL_GPL(register_kretprobes); |
4a296e07 | 1562 | |
4a296e07 MH |
1563 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
1564 | { | |
1565 | unregister_kretprobes(&rp, 1); | |
1566 | } | |
99081ab5 | 1567 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
4a296e07 | 1568 | |
4a296e07 MH |
1569 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) |
1570 | { | |
1571 | int i; | |
1572 | ||
1573 | if (num <= 0) | |
1574 | return; | |
1575 | mutex_lock(&kprobe_mutex); | |
1576 | for (i = 0; i < num; i++) | |
1577 | if (__unregister_kprobe_top(&rps[i]->kp) < 0) | |
1578 | rps[i]->kp.addr = NULL; | |
1579 | mutex_unlock(&kprobe_mutex); | |
1580 | ||
1581 | synchronize_sched(); | |
1582 | for (i = 0; i < num; i++) { | |
1583 | if (rps[i]->kp.addr) { | |
1584 | __unregister_kprobe_bottom(&rps[i]->kp); | |
1585 | cleanup_rp_inst(rps[i]); | |
1586 | } | |
1587 | } | |
1588 | } | |
99081ab5 | 1589 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4a296e07 | 1590 | |
9edddaa2 | 1591 | #else /* CONFIG_KRETPROBES */ |
d0aaff97 | 1592 | int __kprobes register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
1593 | { |
1594 | return -ENOSYS; | |
1595 | } | |
99081ab5 | 1596 | EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce92 | 1597 | |
4a296e07 | 1598 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) |
346fd59b | 1599 | { |
4a296e07 | 1600 | return -ENOSYS; |
346fd59b | 1601 | } |
99081ab5 MH |
1602 | EXPORT_SYMBOL_GPL(register_kretprobes); |
1603 | ||
d0aaff97 | 1604 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
b94cce92 | 1605 | { |
4a296e07 | 1606 | } |
99081ab5 | 1607 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
b94cce92 | 1608 | |
4a296e07 MH |
1609 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) |
1610 | { | |
1611 | } | |
99081ab5 | 1612 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4c4308cb | 1613 | |
4a296e07 MH |
1614 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, |
1615 | struct pt_regs *regs) | |
1616 | { | |
1617 | return 0; | |
b94cce92 HN |
1618 | } |
1619 | ||
4a296e07 MH |
1620 | #endif /* CONFIG_KRETPROBES */ |
1621 | ||
e8386a0c MH |
1622 | /* Set the kprobe gone and remove its instruction buffer. */ |
1623 | static void __kprobes kill_kprobe(struct kprobe *p) | |
1624 | { | |
1625 | struct kprobe *kp; | |
de5bd88d | 1626 | |
e8386a0c | 1627 | p->flags |= KPROBE_FLAG_GONE; |
afd66255 | 1628 | if (kprobe_aggrprobe(p)) { |
e8386a0c MH |
1629 | /* |
1630 | * If this is an aggr_kprobe, we have to list all the | |
1631 | * chained probes and mark them GONE. | |
1632 | */ | |
1633 | list_for_each_entry_rcu(kp, &p->list, list) | |
1634 | kp->flags |= KPROBE_FLAG_GONE; | |
1635 | p->post_handler = NULL; | |
1636 | p->break_handler = NULL; | |
afd66255 | 1637 | kill_optimized_kprobe(p); |
e8386a0c MH |
1638 | } |
1639 | /* | |
1640 | * Here, we can remove insn_slot safely, because no thread calls | |
1641 | * the original probed function (which will be freed soon) any more. | |
1642 | */ | |
1643 | arch_remove_kprobe(p); | |
1644 | } | |
1645 | ||
c0614829 MH |
1646 | /* Disable one kprobe */ |
1647 | int __kprobes disable_kprobe(struct kprobe *kp) | |
1648 | { | |
1649 | int ret = 0; | |
c0614829 MH |
1650 | |
1651 | mutex_lock(&kprobe_mutex); | |
1652 | ||
6f0f1dd7 MH |
1653 | /* Disable this kprobe */ |
1654 | if (__disable_kprobe(kp) == NULL) | |
c0614829 | 1655 | ret = -EINVAL; |
c0614829 | 1656 | |
c0614829 MH |
1657 | mutex_unlock(&kprobe_mutex); |
1658 | return ret; | |
1659 | } | |
1660 | EXPORT_SYMBOL_GPL(disable_kprobe); | |
1661 | ||
1662 | /* Enable one kprobe */ | |
1663 | int __kprobes enable_kprobe(struct kprobe *kp) | |
1664 | { | |
1665 | int ret = 0; | |
1666 | struct kprobe *p; | |
1667 | ||
1668 | mutex_lock(&kprobe_mutex); | |
1669 | ||
1670 | /* Check whether specified probe is valid. */ | |
1671 | p = __get_valid_kprobe(kp); | |
1672 | if (unlikely(p == NULL)) { | |
1673 | ret = -EINVAL; | |
1674 | goto out; | |
1675 | } | |
1676 | ||
1677 | if (kprobe_gone(kp)) { | |
1678 | /* This kprobe has gone, we couldn't enable it. */ | |
1679 | ret = -EINVAL; | |
1680 | goto out; | |
1681 | } | |
1682 | ||
1683 | if (p != kp) | |
1684 | kp->flags &= ~KPROBE_FLAG_DISABLED; | |
1685 | ||
1686 | if (!kprobes_all_disarmed && kprobe_disabled(p)) { | |
1687 | p->flags &= ~KPROBE_FLAG_DISABLED; | |
1688 | arm_kprobe(p); | |
1689 | } | |
1690 | out: | |
1691 | mutex_unlock(&kprobe_mutex); | |
1692 | return ret; | |
1693 | } | |
1694 | EXPORT_SYMBOL_GPL(enable_kprobe); | |
1695 | ||
24851d24 FW |
1696 | void __kprobes dump_kprobe(struct kprobe *kp) |
1697 | { | |
1698 | printk(KERN_WARNING "Dumping kprobe:\n"); | |
1699 | printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n", | |
1700 | kp->symbol_name, kp->addr, kp->offset); | |
1701 | } | |
1702 | ||
e8386a0c MH |
1703 | /* Module notifier call back, checking kprobes on the module */ |
1704 | static int __kprobes kprobes_module_callback(struct notifier_block *nb, | |
1705 | unsigned long val, void *data) | |
1706 | { | |
1707 | struct module *mod = data; | |
1708 | struct hlist_head *head; | |
1709 | struct hlist_node *node; | |
1710 | struct kprobe *p; | |
1711 | unsigned int i; | |
f24659d9 | 1712 | int checkcore = (val == MODULE_STATE_GOING); |
e8386a0c | 1713 | |
f24659d9 | 1714 | if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE) |
e8386a0c MH |
1715 | return NOTIFY_DONE; |
1716 | ||
1717 | /* | |
f24659d9 MH |
1718 | * When MODULE_STATE_GOING was notified, both of module .text and |
1719 | * .init.text sections would be freed. When MODULE_STATE_LIVE was | |
1720 | * notified, only .init.text section would be freed. We need to | |
1721 | * disable kprobes which have been inserted in the sections. | |
e8386a0c MH |
1722 | */ |
1723 | mutex_lock(&kprobe_mutex); | |
1724 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { | |
1725 | head = &kprobe_table[i]; | |
1726 | hlist_for_each_entry_rcu(p, node, head, hlist) | |
f24659d9 MH |
1727 | if (within_module_init((unsigned long)p->addr, mod) || |
1728 | (checkcore && | |
1729 | within_module_core((unsigned long)p->addr, mod))) { | |
e8386a0c MH |
1730 | /* |
1731 | * The vaddr this probe is installed will soon | |
1732 | * be vfreed buy not synced to disk. Hence, | |
1733 | * disarming the breakpoint isn't needed. | |
1734 | */ | |
1735 | kill_kprobe(p); | |
1736 | } | |
1737 | } | |
1738 | mutex_unlock(&kprobe_mutex); | |
1739 | return NOTIFY_DONE; | |
1740 | } | |
1741 | ||
1742 | static struct notifier_block kprobe_module_nb = { | |
1743 | .notifier_call = kprobes_module_callback, | |
1744 | .priority = 0 | |
1745 | }; | |
1746 | ||
1da177e4 LT |
1747 | static int __init init_kprobes(void) |
1748 | { | |
1749 | int i, err = 0; | |
3d8d996e SD |
1750 | unsigned long offset = 0, size = 0; |
1751 | char *modname, namebuf[128]; | |
1752 | const char *symbol_name; | |
1753 | void *addr; | |
1754 | struct kprobe_blackpoint *kb; | |
1da177e4 LT |
1755 | |
1756 | /* FIXME allocate the probe table, currently defined statically */ | |
1757 | /* initialize all list heads */ | |
b94cce92 | 1758 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1da177e4 | 1759 | INIT_HLIST_HEAD(&kprobe_table[i]); |
b94cce92 | 1760 | INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
ef53d9c5 | 1761 | spin_lock_init(&(kretprobe_table_locks[i].lock)); |
b94cce92 | 1762 | } |
1da177e4 | 1763 | |
3d8d996e SD |
1764 | /* |
1765 | * Lookup and populate the kprobe_blacklist. | |
1766 | * | |
1767 | * Unlike the kretprobe blacklist, we'll need to determine | |
1768 | * the range of addresses that belong to the said functions, | |
1769 | * since a kprobe need not necessarily be at the beginning | |
1770 | * of a function. | |
1771 | */ | |
1772 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { | |
1773 | kprobe_lookup_name(kb->name, addr); | |
1774 | if (!addr) | |
1775 | continue; | |
1776 | ||
1777 | kb->start_addr = (unsigned long)addr; | |
1778 | symbol_name = kallsyms_lookup(kb->start_addr, | |
1779 | &size, &offset, &modname, namebuf); | |
1780 | if (!symbol_name) | |
1781 | kb->range = 0; | |
1782 | else | |
1783 | kb->range = size; | |
1784 | } | |
1785 | ||
f438d914 MH |
1786 | if (kretprobe_blacklist_size) { |
1787 | /* lookup the function address from its name */ | |
1788 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
1789 | kprobe_lookup_name(kretprobe_blacklist[i].name, | |
1790 | kretprobe_blacklist[i].addr); | |
1791 | if (!kretprobe_blacklist[i].addr) | |
1792 | printk("kretprobe: lookup failed: %s\n", | |
1793 | kretprobe_blacklist[i].name); | |
1794 | } | |
1795 | } | |
1796 | ||
b2be84df MH |
1797 | #if defined(CONFIG_OPTPROBES) |
1798 | #if defined(__ARCH_WANT_KPROBES_INSN_SLOT) | |
afd66255 MH |
1799 | /* Init kprobe_optinsn_slots */ |
1800 | kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE; | |
1801 | #endif | |
b2be84df MH |
1802 | /* By default, kprobes can be optimized */ |
1803 | kprobes_allow_optimization = true; | |
1804 | #endif | |
afd66255 | 1805 | |
e579abeb MH |
1806 | /* By default, kprobes are armed */ |
1807 | kprobes_all_disarmed = false; | |
bf8f6e5b | 1808 | |
6772926b | 1809 | err = arch_init_kprobes(); |
802eae7c RL |
1810 | if (!err) |
1811 | err = register_die_notifier(&kprobe_exceptions_nb); | |
e8386a0c MH |
1812 | if (!err) |
1813 | err = register_module_notifier(&kprobe_module_nb); | |
1814 | ||
ef53d9c5 | 1815 | kprobes_initialized = (err == 0); |
802eae7c | 1816 | |
8c1c9356 AM |
1817 | if (!err) |
1818 | init_test_probes(); | |
1da177e4 LT |
1819 | return err; |
1820 | } | |
1821 | ||
346fd59b SD |
1822 | #ifdef CONFIG_DEBUG_FS |
1823 | static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p, | |
afd66255 | 1824 | const char *sym, int offset, char *modname, struct kprobe *pp) |
346fd59b SD |
1825 | { |
1826 | char *kprobe_type; | |
1827 | ||
1828 | if (p->pre_handler == pre_handler_kretprobe) | |
1829 | kprobe_type = "r"; | |
1830 | else if (p->pre_handler == setjmp_pre_handler) | |
1831 | kprobe_type = "j"; | |
1832 | else | |
1833 | kprobe_type = "k"; | |
afd66255 | 1834 | |
346fd59b | 1835 | if (sym) |
afd66255 | 1836 | seq_printf(pi, "%p %s %s+0x%x %s ", |
de5bd88d | 1837 | p->addr, kprobe_type, sym, offset, |
afd66255 | 1838 | (modname ? modname : " ")); |
346fd59b | 1839 | else |
afd66255 MH |
1840 | seq_printf(pi, "%p %s %p ", |
1841 | p->addr, kprobe_type, p->addr); | |
1842 | ||
1843 | if (!pp) | |
1844 | pp = p; | |
1845 | seq_printf(pi, "%s%s%s\n", | |
1846 | (kprobe_gone(p) ? "[GONE]" : ""), | |
1847 | ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""), | |
1848 | (kprobe_optimized(pp) ? "[OPTIMIZED]" : "")); | |
346fd59b SD |
1849 | } |
1850 | ||
1851 | static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos) | |
1852 | { | |
1853 | return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; | |
1854 | } | |
1855 | ||
1856 | static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) | |
1857 | { | |
1858 | (*pos)++; | |
1859 | if (*pos >= KPROBE_TABLE_SIZE) | |
1860 | return NULL; | |
1861 | return pos; | |
1862 | } | |
1863 | ||
1864 | static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v) | |
1865 | { | |
1866 | /* Nothing to do */ | |
1867 | } | |
1868 | ||
1869 | static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v) | |
1870 | { | |
1871 | struct hlist_head *head; | |
1872 | struct hlist_node *node; | |
1873 | struct kprobe *p, *kp; | |
1874 | const char *sym = NULL; | |
1875 | unsigned int i = *(loff_t *) v; | |
ffb45122 | 1876 | unsigned long offset = 0; |
346fd59b SD |
1877 | char *modname, namebuf[128]; |
1878 | ||
1879 | head = &kprobe_table[i]; | |
1880 | preempt_disable(); | |
1881 | hlist_for_each_entry_rcu(p, node, head, hlist) { | |
ffb45122 | 1882 | sym = kallsyms_lookup((unsigned long)p->addr, NULL, |
346fd59b | 1883 | &offset, &modname, namebuf); |
afd66255 | 1884 | if (kprobe_aggrprobe(p)) { |
346fd59b | 1885 | list_for_each_entry_rcu(kp, &p->list, list) |
afd66255 | 1886 | report_probe(pi, kp, sym, offset, modname, p); |
346fd59b | 1887 | } else |
afd66255 | 1888 | report_probe(pi, p, sym, offset, modname, NULL); |
346fd59b SD |
1889 | } |
1890 | preempt_enable(); | |
1891 | return 0; | |
1892 | } | |
1893 | ||
88e9d34c | 1894 | static const struct seq_operations kprobes_seq_ops = { |
346fd59b SD |
1895 | .start = kprobe_seq_start, |
1896 | .next = kprobe_seq_next, | |
1897 | .stop = kprobe_seq_stop, | |
1898 | .show = show_kprobe_addr | |
1899 | }; | |
1900 | ||
1901 | static int __kprobes kprobes_open(struct inode *inode, struct file *filp) | |
1902 | { | |
1903 | return seq_open(filp, &kprobes_seq_ops); | |
1904 | } | |
1905 | ||
828c0950 | 1906 | static const struct file_operations debugfs_kprobes_operations = { |
346fd59b SD |
1907 | .open = kprobes_open, |
1908 | .read = seq_read, | |
1909 | .llseek = seq_lseek, | |
1910 | .release = seq_release, | |
1911 | }; | |
1912 | ||
e579abeb | 1913 | static void __kprobes arm_all_kprobes(void) |
bf8f6e5b AM |
1914 | { |
1915 | struct hlist_head *head; | |
1916 | struct hlist_node *node; | |
1917 | struct kprobe *p; | |
1918 | unsigned int i; | |
1919 | ||
1920 | mutex_lock(&kprobe_mutex); | |
1921 | ||
e579abeb MH |
1922 | /* If kprobes are armed, just return */ |
1923 | if (!kprobes_all_disarmed) | |
bf8f6e5b AM |
1924 | goto already_enabled; |
1925 | ||
afd66255 | 1926 | /* Arming kprobes doesn't optimize kprobe itself */ |
4460fdad | 1927 | mutex_lock(&text_mutex); |
bf8f6e5b AM |
1928 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1929 | head = &kprobe_table[i]; | |
1930 | hlist_for_each_entry_rcu(p, node, head, hlist) | |
de5bd88d | 1931 | if (!kprobe_disabled(p)) |
afd66255 | 1932 | __arm_kprobe(p); |
bf8f6e5b | 1933 | } |
4460fdad | 1934 | mutex_unlock(&text_mutex); |
bf8f6e5b | 1935 | |
e579abeb | 1936 | kprobes_all_disarmed = false; |
bf8f6e5b AM |
1937 | printk(KERN_INFO "Kprobes globally enabled\n"); |
1938 | ||
1939 | already_enabled: | |
1940 | mutex_unlock(&kprobe_mutex); | |
1941 | return; | |
1942 | } | |
1943 | ||
e579abeb | 1944 | static void __kprobes disarm_all_kprobes(void) |
bf8f6e5b AM |
1945 | { |
1946 | struct hlist_head *head; | |
1947 | struct hlist_node *node; | |
1948 | struct kprobe *p; | |
1949 | unsigned int i; | |
1950 | ||
1951 | mutex_lock(&kprobe_mutex); | |
1952 | ||
e579abeb MH |
1953 | /* If kprobes are already disarmed, just return */ |
1954 | if (kprobes_all_disarmed) | |
bf8f6e5b AM |
1955 | goto already_disabled; |
1956 | ||
e579abeb | 1957 | kprobes_all_disarmed = true; |
bf8f6e5b | 1958 | printk(KERN_INFO "Kprobes globally disabled\n"); |
afd66255 MH |
1959 | |
1960 | /* | |
1961 | * Here we call get_online_cpus() for avoiding text_mutex deadlock, | |
1962 | * because disarming may also unoptimize kprobes. | |
1963 | */ | |
1964 | get_online_cpus(); | |
4460fdad | 1965 | mutex_lock(&text_mutex); |
bf8f6e5b AM |
1966 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1967 | head = &kprobe_table[i]; | |
1968 | hlist_for_each_entry_rcu(p, node, head, hlist) { | |
de5bd88d | 1969 | if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) |
afd66255 | 1970 | __disarm_kprobe(p); |
bf8f6e5b AM |
1971 | } |
1972 | } | |
1973 | ||
4460fdad | 1974 | mutex_unlock(&text_mutex); |
afd66255 | 1975 | put_online_cpus(); |
bf8f6e5b AM |
1976 | mutex_unlock(&kprobe_mutex); |
1977 | /* Allow all currently running kprobes to complete */ | |
1978 | synchronize_sched(); | |
74a0b576 | 1979 | return; |
bf8f6e5b AM |
1980 | |
1981 | already_disabled: | |
1982 | mutex_unlock(&kprobe_mutex); | |
1983 | return; | |
1984 | } | |
1985 | ||
1986 | /* | |
1987 | * XXX: The debugfs bool file interface doesn't allow for callbacks | |
1988 | * when the bool state is switched. We can reuse that facility when | |
1989 | * available | |
1990 | */ | |
1991 | static ssize_t read_enabled_file_bool(struct file *file, | |
1992 | char __user *user_buf, size_t count, loff_t *ppos) | |
1993 | { | |
1994 | char buf[3]; | |
1995 | ||
e579abeb | 1996 | if (!kprobes_all_disarmed) |
bf8f6e5b AM |
1997 | buf[0] = '1'; |
1998 | else | |
1999 | buf[0] = '0'; | |
2000 | buf[1] = '\n'; | |
2001 | buf[2] = 0x00; | |
2002 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); | |
2003 | } | |
2004 | ||
2005 | static ssize_t write_enabled_file_bool(struct file *file, | |
2006 | const char __user *user_buf, size_t count, loff_t *ppos) | |
2007 | { | |
2008 | char buf[32]; | |
2009 | int buf_size; | |
2010 | ||
2011 | buf_size = min(count, (sizeof(buf)-1)); | |
2012 | if (copy_from_user(buf, user_buf, buf_size)) | |
2013 | return -EFAULT; | |
2014 | ||
2015 | switch (buf[0]) { | |
2016 | case 'y': | |
2017 | case 'Y': | |
2018 | case '1': | |
e579abeb | 2019 | arm_all_kprobes(); |
bf8f6e5b AM |
2020 | break; |
2021 | case 'n': | |
2022 | case 'N': | |
2023 | case '0': | |
e579abeb | 2024 | disarm_all_kprobes(); |
bf8f6e5b AM |
2025 | break; |
2026 | } | |
2027 | ||
2028 | return count; | |
2029 | } | |
2030 | ||
828c0950 | 2031 | static const struct file_operations fops_kp = { |
bf8f6e5b AM |
2032 | .read = read_enabled_file_bool, |
2033 | .write = write_enabled_file_bool, | |
6038f373 | 2034 | .llseek = default_llseek, |
bf8f6e5b AM |
2035 | }; |
2036 | ||
346fd59b SD |
2037 | static int __kprobes debugfs_kprobe_init(void) |
2038 | { | |
2039 | struct dentry *dir, *file; | |
bf8f6e5b | 2040 | unsigned int value = 1; |
346fd59b SD |
2041 | |
2042 | dir = debugfs_create_dir("kprobes", NULL); | |
2043 | if (!dir) | |
2044 | return -ENOMEM; | |
2045 | ||
e3869792 | 2046 | file = debugfs_create_file("list", 0444, dir, NULL, |
346fd59b SD |
2047 | &debugfs_kprobes_operations); |
2048 | if (!file) { | |
2049 | debugfs_remove(dir); | |
2050 | return -ENOMEM; | |
2051 | } | |
2052 | ||
bf8f6e5b AM |
2053 | file = debugfs_create_file("enabled", 0600, dir, |
2054 | &value, &fops_kp); | |
2055 | if (!file) { | |
2056 | debugfs_remove(dir); | |
2057 | return -ENOMEM; | |
2058 | } | |
2059 | ||
346fd59b SD |
2060 | return 0; |
2061 | } | |
2062 | ||
2063 | late_initcall(debugfs_kprobe_init); | |
2064 | #endif /* CONFIG_DEBUG_FS */ | |
2065 | ||
2066 | module_init(init_kprobes); | |
1da177e4 | 2067 | |
99081ab5 | 2068 | /* defined in arch/.../kernel/kprobes.c */ |
1da177e4 | 2069 | EXPORT_SYMBOL_GPL(jprobe_return); |