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