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> | |
35 | #include <linux/spinlock.h> | |
36 | #include <linux/hash.h> | |
37 | #include <linux/init.h> | |
4e57b681 | 38 | #include <linux/slab.h> |
1da177e4 | 39 | #include <linux/module.h> |
9ec4b1f3 | 40 | #include <linux/moduleloader.h> |
d0aaff97 | 41 | #include <asm-generic/sections.h> |
1da177e4 LT |
42 | #include <asm/cacheflush.h> |
43 | #include <asm/errno.h> | |
44 | #include <asm/kdebug.h> | |
45 | ||
46 | #define KPROBE_HASH_BITS 6 | |
47 | #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS) | |
48 | ||
49 | static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; | |
b94cce92 | 50 | static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; |
1da177e4 LT |
51 | |
52 | unsigned int kprobe_cpu = NR_CPUS; | |
53 | static DEFINE_SPINLOCK(kprobe_lock); | |
e6584523 | 54 | static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; |
1da177e4 | 55 | |
9ec4b1f3 AM |
56 | /* |
57 | * kprobe->ainsn.insn points to the copy of the instruction to be | |
58 | * single-stepped. x86_64, POWER4 and above have no-exec support and | |
59 | * stepping on the instruction on a vmalloced/kmalloced/data page | |
60 | * is a recipe for disaster | |
61 | */ | |
62 | #define INSNS_PER_PAGE (PAGE_SIZE/(MAX_INSN_SIZE * sizeof(kprobe_opcode_t))) | |
63 | ||
64 | struct kprobe_insn_page { | |
65 | struct hlist_node hlist; | |
66 | kprobe_opcode_t *insns; /* Page of instruction slots */ | |
67 | char slot_used[INSNS_PER_PAGE]; | |
68 | int nused; | |
69 | }; | |
70 | ||
71 | static struct hlist_head kprobe_insn_pages; | |
72 | ||
73 | /** | |
74 | * get_insn_slot() - Find a slot on an executable page for an instruction. | |
75 | * We allocate an executable page if there's no room on existing ones. | |
76 | */ | |
d0aaff97 | 77 | kprobe_opcode_t __kprobes *get_insn_slot(void) |
9ec4b1f3 AM |
78 | { |
79 | struct kprobe_insn_page *kip; | |
80 | struct hlist_node *pos; | |
81 | ||
82 | hlist_for_each(pos, &kprobe_insn_pages) { | |
83 | kip = hlist_entry(pos, struct kprobe_insn_page, hlist); | |
84 | if (kip->nused < INSNS_PER_PAGE) { | |
85 | int i; | |
86 | for (i = 0; i < INSNS_PER_PAGE; i++) { | |
87 | if (!kip->slot_used[i]) { | |
88 | kip->slot_used[i] = 1; | |
89 | kip->nused++; | |
90 | return kip->insns + (i * MAX_INSN_SIZE); | |
91 | } | |
92 | } | |
93 | /* Surprise! No unused slots. Fix kip->nused. */ | |
94 | kip->nused = INSNS_PER_PAGE; | |
95 | } | |
96 | } | |
97 | ||
98 | /* All out of space. Need to allocate a new page. Use slot 0.*/ | |
99 | kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL); | |
100 | if (!kip) { | |
101 | return NULL; | |
102 | } | |
103 | ||
104 | /* | |
105 | * Use module_alloc so this page is within +/- 2GB of where the | |
106 | * kernel image and loaded module images reside. This is required | |
107 | * so x86_64 can correctly handle the %rip-relative fixups. | |
108 | */ | |
109 | kip->insns = module_alloc(PAGE_SIZE); | |
110 | if (!kip->insns) { | |
111 | kfree(kip); | |
112 | return NULL; | |
113 | } | |
114 | INIT_HLIST_NODE(&kip->hlist); | |
115 | hlist_add_head(&kip->hlist, &kprobe_insn_pages); | |
116 | memset(kip->slot_used, 0, INSNS_PER_PAGE); | |
117 | kip->slot_used[0] = 1; | |
118 | kip->nused = 1; | |
119 | return kip->insns; | |
120 | } | |
121 | ||
d0aaff97 | 122 | void __kprobes free_insn_slot(kprobe_opcode_t *slot) |
9ec4b1f3 AM |
123 | { |
124 | struct kprobe_insn_page *kip; | |
125 | struct hlist_node *pos; | |
126 | ||
127 | hlist_for_each(pos, &kprobe_insn_pages) { | |
128 | kip = hlist_entry(pos, struct kprobe_insn_page, hlist); | |
129 | if (kip->insns <= slot && | |
130 | slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) { | |
131 | int i = (slot - kip->insns) / MAX_INSN_SIZE; | |
132 | kip->slot_used[i] = 0; | |
133 | kip->nused--; | |
134 | if (kip->nused == 0) { | |
135 | /* | |
136 | * Page is no longer in use. Free it unless | |
137 | * it's the last one. We keep the last one | |
138 | * so as not to have to set it up again the | |
139 | * next time somebody inserts a probe. | |
140 | */ | |
141 | hlist_del(&kip->hlist); | |
142 | if (hlist_empty(&kprobe_insn_pages)) { | |
143 | INIT_HLIST_NODE(&kip->hlist); | |
144 | hlist_add_head(&kip->hlist, | |
145 | &kprobe_insn_pages); | |
146 | } else { | |
147 | module_free(NULL, kip->insns); | |
148 | kfree(kip); | |
149 | } | |
150 | } | |
151 | return; | |
152 | } | |
153 | } | |
154 | } | |
155 | ||
1da177e4 | 156 | /* Locks kprobe: irqs must be disabled */ |
d0aaff97 | 157 | void __kprobes lock_kprobes(void) |
1da177e4 | 158 | { |
deac66ae KA |
159 | unsigned long flags = 0; |
160 | ||
161 | /* Avoiding local interrupts to happen right after we take the kprobe_lock | |
162 | * and before we get a chance to update kprobe_cpu, this to prevent | |
163 | * deadlock when we have a kprobe on ISR routine and a kprobe on task | |
164 | * routine | |
165 | */ | |
166 | local_irq_save(flags); | |
167 | ||
1da177e4 LT |
168 | spin_lock(&kprobe_lock); |
169 | kprobe_cpu = smp_processor_id(); | |
deac66ae KA |
170 | |
171 | local_irq_restore(flags); | |
1da177e4 LT |
172 | } |
173 | ||
d0aaff97 | 174 | void __kprobes unlock_kprobes(void) |
1da177e4 | 175 | { |
deac66ae KA |
176 | unsigned long flags = 0; |
177 | ||
178 | /* Avoiding local interrupts to happen right after we update | |
179 | * kprobe_cpu and before we get a a chance to release kprobe_lock, | |
180 | * this to prevent deadlock when we have a kprobe on ISR routine and | |
181 | * a kprobe on task routine | |
182 | */ | |
183 | local_irq_save(flags); | |
184 | ||
1da177e4 LT |
185 | kprobe_cpu = NR_CPUS; |
186 | spin_unlock(&kprobe_lock); | |
deac66ae KA |
187 | |
188 | local_irq_restore(flags); | |
1da177e4 LT |
189 | } |
190 | ||
e6584523 AM |
191 | /* We have preemption disabled.. so it is safe to use __ versions */ |
192 | static inline void set_kprobe_instance(struct kprobe *kp) | |
193 | { | |
194 | __get_cpu_var(kprobe_instance) = kp; | |
195 | } | |
196 | ||
197 | static inline void reset_kprobe_instance(void) | |
198 | { | |
199 | __get_cpu_var(kprobe_instance) = NULL; | |
200 | } | |
201 | ||
1da177e4 | 202 | /* You have to be holding the kprobe_lock */ |
d0aaff97 | 203 | struct kprobe __kprobes *get_kprobe(void *addr) |
1da177e4 LT |
204 | { |
205 | struct hlist_head *head; | |
206 | struct hlist_node *node; | |
207 | ||
208 | head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; | |
209 | hlist_for_each(node, head) { | |
210 | struct kprobe *p = hlist_entry(node, struct kprobe, hlist); | |
211 | if (p->addr == addr) | |
212 | return p; | |
213 | } | |
214 | return NULL; | |
215 | } | |
216 | ||
64f562c6 AM |
217 | /* |
218 | * Aggregate handlers for multiple kprobes support - these handlers | |
219 | * take care of invoking the individual kprobe handlers on p->list | |
220 | */ | |
d0aaff97 | 221 | static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
64f562c6 AM |
222 | { |
223 | struct kprobe *kp; | |
224 | ||
225 | list_for_each_entry(kp, &p->list, list) { | |
226 | if (kp->pre_handler) { | |
e6584523 | 227 | set_kprobe_instance(kp); |
8b0914ea PP |
228 | if (kp->pre_handler(kp, regs)) |
229 | return 1; | |
64f562c6 | 230 | } |
e6584523 | 231 | reset_kprobe_instance(); |
64f562c6 AM |
232 | } |
233 | return 0; | |
234 | } | |
235 | ||
d0aaff97 PP |
236 | static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
237 | unsigned long flags) | |
64f562c6 AM |
238 | { |
239 | struct kprobe *kp; | |
240 | ||
241 | list_for_each_entry(kp, &p->list, list) { | |
242 | if (kp->post_handler) { | |
e6584523 | 243 | set_kprobe_instance(kp); |
64f562c6 | 244 | kp->post_handler(kp, regs, flags); |
e6584523 | 245 | reset_kprobe_instance(); |
64f562c6 AM |
246 | } |
247 | } | |
248 | return; | |
249 | } | |
250 | ||
d0aaff97 PP |
251 | static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, |
252 | int trapnr) | |
64f562c6 | 253 | { |
e6584523 AM |
254 | struct kprobe *cur = __get_cpu_var(kprobe_instance); |
255 | ||
64f562c6 AM |
256 | /* |
257 | * if we faulted "during" the execution of a user specified | |
258 | * probe handler, invoke just that probe's fault handler | |
259 | */ | |
e6584523 AM |
260 | if (cur && cur->fault_handler) { |
261 | if (cur->fault_handler(cur, regs, trapnr)) | |
64f562c6 AM |
262 | return 1; |
263 | } | |
264 | return 0; | |
265 | } | |
266 | ||
d0aaff97 | 267 | static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs) |
8b0914ea | 268 | { |
e6584523 AM |
269 | struct kprobe *cur = __get_cpu_var(kprobe_instance); |
270 | int ret = 0; | |
271 | ||
272 | if (cur && cur->break_handler) { | |
273 | if (cur->break_handler(cur, regs)) | |
274 | ret = 1; | |
8b0914ea | 275 | } |
e6584523 AM |
276 | reset_kprobe_instance(); |
277 | return ret; | |
8b0914ea PP |
278 | } |
279 | ||
d0aaff97 | 280 | struct kretprobe_instance __kprobes *get_free_rp_inst(struct kretprobe *rp) |
b94cce92 HN |
281 | { |
282 | struct hlist_node *node; | |
283 | struct kretprobe_instance *ri; | |
284 | hlist_for_each_entry(ri, node, &rp->free_instances, uflist) | |
285 | return ri; | |
286 | return NULL; | |
287 | } | |
288 | ||
d0aaff97 PP |
289 | static struct kretprobe_instance __kprobes *get_used_rp_inst(struct kretprobe |
290 | *rp) | |
b94cce92 HN |
291 | { |
292 | struct hlist_node *node; | |
293 | struct kretprobe_instance *ri; | |
294 | hlist_for_each_entry(ri, node, &rp->used_instances, uflist) | |
295 | return ri; | |
296 | return NULL; | |
297 | } | |
298 | ||
d0aaff97 | 299 | void __kprobes add_rp_inst(struct kretprobe_instance *ri) |
b94cce92 | 300 | { |
b94cce92 HN |
301 | /* |
302 | * Remove rp inst off the free list - | |
303 | * Add it back when probed function returns | |
304 | */ | |
305 | hlist_del(&ri->uflist); | |
802eae7c | 306 | |
b94cce92 HN |
307 | /* Add rp inst onto table */ |
308 | INIT_HLIST_NODE(&ri->hlist); | |
309 | hlist_add_head(&ri->hlist, | |
802eae7c | 310 | &kretprobe_inst_table[hash_ptr(ri->task, KPROBE_HASH_BITS)]); |
b94cce92 HN |
311 | |
312 | /* Also add this rp inst to the used list. */ | |
313 | INIT_HLIST_NODE(&ri->uflist); | |
314 | hlist_add_head(&ri->uflist, &ri->rp->used_instances); | |
315 | } | |
316 | ||
d0aaff97 | 317 | void __kprobes recycle_rp_inst(struct kretprobe_instance *ri) |
b94cce92 HN |
318 | { |
319 | /* remove rp inst off the rprobe_inst_table */ | |
320 | hlist_del(&ri->hlist); | |
321 | if (ri->rp) { | |
322 | /* remove rp inst off the used list */ | |
323 | hlist_del(&ri->uflist); | |
324 | /* put rp inst back onto the free list */ | |
325 | INIT_HLIST_NODE(&ri->uflist); | |
326 | hlist_add_head(&ri->uflist, &ri->rp->free_instances); | |
327 | } else | |
328 | /* Unregistering */ | |
329 | kfree(ri); | |
330 | } | |
331 | ||
d0aaff97 | 332 | struct hlist_head __kprobes *kretprobe_inst_table_head(struct task_struct *tsk) |
b94cce92 HN |
333 | { |
334 | return &kretprobe_inst_table[hash_ptr(tsk, KPROBE_HASH_BITS)]; | |
335 | } | |
336 | ||
b94cce92 | 337 | /* |
802eae7c RL |
338 | * This function is called from exit_thread or flush_thread when task tk's |
339 | * stack is being recycled so that we can recycle any function-return probe | |
340 | * instances associated with this task. These left over instances represent | |
341 | * probed functions that have been called but will never return. | |
b94cce92 | 342 | */ |
d0aaff97 | 343 | void __kprobes kprobe_flush_task(struct task_struct *tk) |
b94cce92 | 344 | { |
802eae7c RL |
345 | struct kretprobe_instance *ri; |
346 | struct hlist_head *head; | |
347 | struct hlist_node *node, *tmp; | |
0aa55e4d | 348 | unsigned long flags = 0; |
802eae7c | 349 | |
0aa55e4d | 350 | spin_lock_irqsave(&kprobe_lock, flags); |
802eae7c RL |
351 | head = kretprobe_inst_table_head(current); |
352 | hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { | |
353 | if (ri->task == tk) | |
354 | recycle_rp_inst(ri); | |
355 | } | |
0aa55e4d | 356 | spin_unlock_irqrestore(&kprobe_lock, flags); |
b94cce92 HN |
357 | } |
358 | ||
359 | /* | |
360 | * This kprobe pre_handler is registered with every kretprobe. When probe | |
361 | * hits it will set up the return probe. | |
362 | */ | |
d0aaff97 PP |
363 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, |
364 | struct pt_regs *regs) | |
b94cce92 HN |
365 | { |
366 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); | |
367 | ||
368 | /*TODO: consider to only swap the RA after the last pre_handler fired */ | |
369 | arch_prepare_kretprobe(rp, regs); | |
370 | return 0; | |
371 | } | |
372 | ||
373 | static inline void free_rp_inst(struct kretprobe *rp) | |
374 | { | |
375 | struct kretprobe_instance *ri; | |
376 | while ((ri = get_free_rp_inst(rp)) != NULL) { | |
377 | hlist_del(&ri->uflist); | |
378 | kfree(ri); | |
379 | } | |
380 | } | |
381 | ||
8b0914ea PP |
382 | /* |
383 | * Keep all fields in the kprobe consistent | |
384 | */ | |
385 | static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p) | |
386 | { | |
387 | memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t)); | |
388 | memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn)); | |
389 | } | |
390 | ||
391 | /* | |
392 | * Add the new probe to old_p->list. Fail if this is the | |
393 | * second jprobe at the address - two jprobes can't coexist | |
394 | */ | |
d0aaff97 | 395 | static int __kprobes add_new_kprobe(struct kprobe *old_p, struct kprobe *p) |
8b0914ea PP |
396 | { |
397 | struct kprobe *kp; | |
398 | ||
399 | if (p->break_handler) { | |
400 | list_for_each_entry(kp, &old_p->list, list) { | |
401 | if (kp->break_handler) | |
402 | return -EEXIST; | |
403 | } | |
404 | list_add_tail(&p->list, &old_p->list); | |
405 | } else | |
406 | list_add(&p->list, &old_p->list); | |
407 | return 0; | |
408 | } | |
409 | ||
64f562c6 AM |
410 | /* |
411 | * Fill in the required fields of the "manager kprobe". Replace the | |
412 | * earlier kprobe in the hlist with the manager kprobe | |
413 | */ | |
414 | static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p) | |
415 | { | |
8b0914ea | 416 | copy_kprobe(p, ap); |
64f562c6 | 417 | ap->addr = p->addr; |
64f562c6 AM |
418 | ap->pre_handler = aggr_pre_handler; |
419 | ap->post_handler = aggr_post_handler; | |
420 | ap->fault_handler = aggr_fault_handler; | |
8b0914ea | 421 | ap->break_handler = aggr_break_handler; |
64f562c6 AM |
422 | |
423 | INIT_LIST_HEAD(&ap->list); | |
424 | list_add(&p->list, &ap->list); | |
425 | ||
426 | INIT_HLIST_NODE(&ap->hlist); | |
427 | hlist_del(&p->hlist); | |
428 | hlist_add_head(&ap->hlist, | |
429 | &kprobe_table[hash_ptr(ap->addr, KPROBE_HASH_BITS)]); | |
430 | } | |
431 | ||
432 | /* | |
433 | * This is the second or subsequent kprobe at the address - handle | |
434 | * the intricacies | |
435 | * TODO: Move kcalloc outside the spinlock | |
436 | */ | |
d0aaff97 PP |
437 | static int __kprobes register_aggr_kprobe(struct kprobe *old_p, |
438 | struct kprobe *p) | |
64f562c6 AM |
439 | { |
440 | int ret = 0; | |
441 | struct kprobe *ap; | |
442 | ||
8b0914ea PP |
443 | if (old_p->pre_handler == aggr_pre_handler) { |
444 | copy_kprobe(old_p, p); | |
445 | ret = add_new_kprobe(old_p, p); | |
64f562c6 AM |
446 | } else { |
447 | ap = kcalloc(1, sizeof(struct kprobe), GFP_ATOMIC); | |
448 | if (!ap) | |
449 | return -ENOMEM; | |
450 | add_aggr_kprobe(ap, old_p); | |
8b0914ea PP |
451 | copy_kprobe(ap, p); |
452 | ret = add_new_kprobe(ap, p); | |
64f562c6 AM |
453 | } |
454 | return ret; | |
455 | } | |
456 | ||
457 | /* kprobe removal house-keeping routines */ | |
458 | static inline void cleanup_kprobe(struct kprobe *p, unsigned long flags) | |
459 | { | |
7e1048b1 | 460 | arch_disarm_kprobe(p); |
64f562c6 | 461 | hlist_del(&p->hlist); |
64f562c6 AM |
462 | spin_unlock_irqrestore(&kprobe_lock, flags); |
463 | arch_remove_kprobe(p); | |
464 | } | |
465 | ||
466 | static inline void cleanup_aggr_kprobe(struct kprobe *old_p, | |
467 | struct kprobe *p, unsigned long flags) | |
468 | { | |
469 | list_del(&p->list); | |
470 | if (list_empty(&old_p->list)) { | |
471 | cleanup_kprobe(old_p, flags); | |
472 | kfree(old_p); | |
473 | } else | |
474 | spin_unlock_irqrestore(&kprobe_lock, flags); | |
475 | } | |
476 | ||
d0aaff97 PP |
477 | static int __kprobes in_kprobes_functions(unsigned long addr) |
478 | { | |
479 | if (addr >= (unsigned long)__kprobes_text_start | |
480 | && addr < (unsigned long)__kprobes_text_end) | |
481 | return -EINVAL; | |
482 | return 0; | |
483 | } | |
484 | ||
485 | int __kprobes register_kprobe(struct kprobe *p) | |
1da177e4 LT |
486 | { |
487 | int ret = 0; | |
488 | unsigned long flags = 0; | |
64f562c6 | 489 | struct kprobe *old_p; |
1da177e4 | 490 | |
d0aaff97 PP |
491 | if ((ret = in_kprobes_functions((unsigned long) p->addr)) != 0) |
492 | return ret; | |
493 | if ((ret = arch_prepare_kprobe(p)) != 0) | |
1da177e4 | 494 | goto rm_kprobe; |
d0aaff97 | 495 | |
1da177e4 | 496 | spin_lock_irqsave(&kprobe_lock, flags); |
64f562c6 | 497 | old_p = get_kprobe(p->addr); |
ea32c65c | 498 | p->nmissed = 0; |
64f562c6 AM |
499 | if (old_p) { |
500 | ret = register_aggr_kprobe(old_p, p); | |
1da177e4 LT |
501 | goto out; |
502 | } | |
1da177e4 | 503 | |
64f562c6 AM |
504 | arch_copy_kprobe(p); |
505 | INIT_HLIST_NODE(&p->hlist); | |
1da177e4 LT |
506 | hlist_add_head(&p->hlist, |
507 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); | |
508 | ||
7e1048b1 RL |
509 | arch_arm_kprobe(p); |
510 | ||
1da177e4 LT |
511 | out: |
512 | spin_unlock_irqrestore(&kprobe_lock, flags); | |
513 | rm_kprobe: | |
514 | if (ret == -EEXIST) | |
515 | arch_remove_kprobe(p); | |
516 | return ret; | |
517 | } | |
518 | ||
d0aaff97 | 519 | void __kprobes unregister_kprobe(struct kprobe *p) |
1da177e4 LT |
520 | { |
521 | unsigned long flags; | |
64f562c6 AM |
522 | struct kprobe *old_p; |
523 | ||
1da177e4 | 524 | spin_lock_irqsave(&kprobe_lock, flags); |
64f562c6 AM |
525 | old_p = get_kprobe(p->addr); |
526 | if (old_p) { | |
527 | if (old_p->pre_handler == aggr_pre_handler) | |
528 | cleanup_aggr_kprobe(old_p, p, flags); | |
529 | else | |
530 | cleanup_kprobe(p, flags); | |
531 | } else | |
04dea5f9 | 532 | spin_unlock_irqrestore(&kprobe_lock, flags); |
1da177e4 LT |
533 | } |
534 | ||
535 | static struct notifier_block kprobe_exceptions_nb = { | |
536 | .notifier_call = kprobe_exceptions_notify, | |
537 | .priority = 0x7fffffff /* we need to notified first */ | |
538 | }; | |
539 | ||
d0aaff97 | 540 | int __kprobes register_jprobe(struct jprobe *jp) |
1da177e4 LT |
541 | { |
542 | /* Todo: Verify probepoint is a function entry point */ | |
543 | jp->kp.pre_handler = setjmp_pre_handler; | |
544 | jp->kp.break_handler = longjmp_break_handler; | |
545 | ||
546 | return register_kprobe(&jp->kp); | |
547 | } | |
548 | ||
d0aaff97 | 549 | void __kprobes unregister_jprobe(struct jprobe *jp) |
1da177e4 LT |
550 | { |
551 | unregister_kprobe(&jp->kp); | |
552 | } | |
553 | ||
b94cce92 HN |
554 | #ifdef ARCH_SUPPORTS_KRETPROBES |
555 | ||
d0aaff97 | 556 | int __kprobes register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
557 | { |
558 | int ret = 0; | |
559 | struct kretprobe_instance *inst; | |
560 | int i; | |
561 | ||
562 | rp->kp.pre_handler = pre_handler_kretprobe; | |
563 | ||
564 | /* Pre-allocate memory for max kretprobe instances */ | |
565 | if (rp->maxactive <= 0) { | |
566 | #ifdef CONFIG_PREEMPT | |
567 | rp->maxactive = max(10, 2 * NR_CPUS); | |
568 | #else | |
569 | rp->maxactive = NR_CPUS; | |
570 | #endif | |
571 | } | |
572 | INIT_HLIST_HEAD(&rp->used_instances); | |
573 | INIT_HLIST_HEAD(&rp->free_instances); | |
574 | for (i = 0; i < rp->maxactive; i++) { | |
575 | inst = kmalloc(sizeof(struct kretprobe_instance), GFP_KERNEL); | |
576 | if (inst == NULL) { | |
577 | free_rp_inst(rp); | |
578 | return -ENOMEM; | |
579 | } | |
580 | INIT_HLIST_NODE(&inst->uflist); | |
581 | hlist_add_head(&inst->uflist, &rp->free_instances); | |
582 | } | |
583 | ||
584 | rp->nmissed = 0; | |
585 | /* Establish function entry probe point */ | |
586 | if ((ret = register_kprobe(&rp->kp)) != 0) | |
587 | free_rp_inst(rp); | |
588 | return ret; | |
589 | } | |
590 | ||
591 | #else /* ARCH_SUPPORTS_KRETPROBES */ | |
592 | ||
d0aaff97 | 593 | int __kprobes register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
594 | { |
595 | return -ENOSYS; | |
596 | } | |
597 | ||
598 | #endif /* ARCH_SUPPORTS_KRETPROBES */ | |
599 | ||
d0aaff97 | 600 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
601 | { |
602 | unsigned long flags; | |
603 | struct kretprobe_instance *ri; | |
604 | ||
605 | unregister_kprobe(&rp->kp); | |
606 | /* No race here */ | |
607 | spin_lock_irqsave(&kprobe_lock, flags); | |
608 | free_rp_inst(rp); | |
609 | while ((ri = get_used_rp_inst(rp)) != NULL) { | |
610 | ri->rp = NULL; | |
611 | hlist_del(&ri->uflist); | |
612 | } | |
613 | spin_unlock_irqrestore(&kprobe_lock, flags); | |
614 | } | |
615 | ||
1da177e4 LT |
616 | static int __init init_kprobes(void) |
617 | { | |
618 | int i, err = 0; | |
619 | ||
620 | /* FIXME allocate the probe table, currently defined statically */ | |
621 | /* initialize all list heads */ | |
b94cce92 | 622 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1da177e4 | 623 | INIT_HLIST_HEAD(&kprobe_table[i]); |
b94cce92 HN |
624 | INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
625 | } | |
1da177e4 | 626 | |
6772926b | 627 | err = arch_init_kprobes(); |
802eae7c RL |
628 | if (!err) |
629 | err = register_die_notifier(&kprobe_exceptions_nb); | |
630 | ||
1da177e4 LT |
631 | return err; |
632 | } | |
633 | ||
634 | __initcall(init_kprobes); | |
635 | ||
636 | EXPORT_SYMBOL_GPL(register_kprobe); | |
637 | EXPORT_SYMBOL_GPL(unregister_kprobe); | |
638 | EXPORT_SYMBOL_GPL(register_jprobe); | |
639 | EXPORT_SYMBOL_GPL(unregister_jprobe); | |
640 | EXPORT_SYMBOL_GPL(jprobe_return); | |
b94cce92 HN |
641 | EXPORT_SYMBOL_GPL(register_kretprobe); |
642 | EXPORT_SYMBOL_GPL(unregister_kretprobe); | |
643 |