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24ba613c AS |
1 | /* |
2 | * arch/arm/kernel/kprobes.c | |
3 | * | |
4 | * Kprobes on ARM | |
5 | * | |
6 | * Abhishek Sagar <sagar.abhishek@gmail.com> | |
7 | * Copyright (C) 2006, 2007 Motorola Inc. | |
8 | * | |
9 | * Nicolas Pitre <nico@marvell.com> | |
10 | * Copyright (C) 2007 Marvell Ltd. | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or modify | |
13 | * it under the terms of the GNU General Public License version 2 as | |
14 | * published by the Free Software Foundation. | |
15 | * | |
16 | * This program is distributed in the hope that it will be useful, | |
17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
19 | * General Public License for more details. | |
20 | */ | |
21 | ||
22 | #include <linux/kernel.h> | |
23 | #include <linux/kprobes.h> | |
24 | #include <linux/module.h> | |
5a0e3ad6 | 25 | #include <linux/slab.h> |
2003b7af | 26 | #include <linux/stop_machine.h> |
24ba613c AS |
27 | #include <linux/stringify.h> |
28 | #include <asm/traps.h> | |
29 | #include <asm/cacheflush.h> | |
30 | ||
221bf15f | 31 | #include "kprobes.h" |
b21d55e9 | 32 | #include "patch.h" |
221bf15f | 33 | |
24ba613c AS |
34 | #define MIN_STACK_SIZE(addr) \ |
35 | min((unsigned long)MAX_STACK_SIZE, \ | |
36 | (unsigned long)current_thread_info() + THREAD_START_SP - (addr)) | |
37 | ||
aceb487a | 38 | #define flush_insns(addr, size) \ |
24ba613c AS |
39 | flush_icache_range((unsigned long)(addr), \ |
40 | (unsigned long)(addr) + \ | |
aceb487a | 41 | (size)) |
24ba613c AS |
42 | |
43 | /* Used as a marker in ARM_pc to note when we're in a jprobe. */ | |
44 | #define JPROBE_MAGIC_ADDR 0xffffffff | |
45 | ||
46 | DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; | |
47 | DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); | |
48 | ||
49 | ||
50 | int __kprobes arch_prepare_kprobe(struct kprobe *p) | |
51 | { | |
52 | kprobe_opcode_t insn; | |
53 | kprobe_opcode_t tmp_insn[MAX_INSN_SIZE]; | |
54 | unsigned long addr = (unsigned long)p->addr; | |
e2960317 | 55 | bool thumb; |
24371707 | 56 | kprobe_decode_insn_t *decode_insn; |
24ba613c AS |
57 | int is; |
58 | ||
24371707 | 59 | if (in_exception_text(addr)) |
24ba613c AS |
60 | return -EINVAL; |
61 | ||
24371707 | 62 | #ifdef CONFIG_THUMB2_KERNEL |
e2960317 | 63 | thumb = true; |
24371707 JM |
64 | addr &= ~1; /* Bit 0 would normally be set to indicate Thumb code */ |
65 | insn = ((u16 *)addr)[0]; | |
66 | if (is_wide_instruction(insn)) { | |
67 | insn <<= 16; | |
68 | insn |= ((u16 *)addr)[1]; | |
69 | decode_insn = thumb32_kprobe_decode_insn; | |
70 | } else | |
71 | decode_insn = thumb16_kprobe_decode_insn; | |
72 | #else /* !CONFIG_THUMB2_KERNEL */ | |
e2960317 | 73 | thumb = false; |
24371707 JM |
74 | if (addr & 0x3) |
75 | return -EINVAL; | |
24ba613c | 76 | insn = *p->addr; |
24371707 JM |
77 | decode_insn = arm_kprobe_decode_insn; |
78 | #endif | |
79 | ||
24ba613c AS |
80 | p->opcode = insn; |
81 | p->ainsn.insn = tmp_insn; | |
82 | ||
24371707 | 83 | switch ((*decode_insn)(insn, &p->ainsn)) { |
24ba613c AS |
84 | case INSN_REJECTED: /* not supported */ |
85 | return -EINVAL; | |
86 | ||
87 | case INSN_GOOD: /* instruction uses slot */ | |
88 | p->ainsn.insn = get_insn_slot(); | |
89 | if (!p->ainsn.insn) | |
90 | return -ENOMEM; | |
91 | for (is = 0; is < MAX_INSN_SIZE; ++is) | |
92 | p->ainsn.insn[is] = tmp_insn[is]; | |
aceb487a JM |
93 | flush_insns(p->ainsn.insn, |
94 | sizeof(p->ainsn.insn[0]) * MAX_INSN_SIZE); | |
e2960317 JM |
95 | p->ainsn.insn_fn = (kprobe_insn_fn_t *) |
96 | ((uintptr_t)p->ainsn.insn | thumb); | |
24ba613c AS |
97 | break; |
98 | ||
99 | case INSN_GOOD_NO_SLOT: /* instruction doesn't need insn slot */ | |
100 | p->ainsn.insn = NULL; | |
101 | break; | |
102 | } | |
103 | ||
104 | return 0; | |
105 | } | |
106 | ||
107 | void __kprobes arch_arm_kprobe(struct kprobe *p) | |
108 | { | |
b21d55e9 RV |
109 | unsigned int brkp; |
110 | void *addr; | |
111 | ||
112 | if (IS_ENABLED(CONFIG_THUMB2_KERNEL)) { | |
113 | /* Remove any Thumb flag */ | |
114 | addr = (void *)((uintptr_t)p->addr & ~1); | |
115 | ||
116 | if (is_wide_instruction(p->opcode)) | |
117 | brkp = KPROBE_THUMB32_BREAKPOINT_INSTRUCTION; | |
118 | else | |
119 | brkp = KPROBE_THUMB16_BREAKPOINT_INSTRUCTION; | |
aceb487a | 120 | } else { |
b21d55e9 | 121 | kprobe_opcode_t insn = p->opcode; |
24ba613c | 122 | |
b21d55e9 RV |
123 | addr = p->addr; |
124 | brkp = KPROBE_ARM_BREAKPOINT_INSTRUCTION; | |
aceb487a | 125 | |
b21d55e9 RV |
126 | if (insn >= 0xe0000000) |
127 | brkp |= 0xe0000000; /* Unconditional instruction */ | |
128 | else | |
129 | brkp |= insn & 0xf0000000; /* Copy condition from insn */ | |
130 | } | |
aceb487a | 131 | |
b21d55e9 RV |
132 | patch_text(addr, brkp); |
133 | } | |
aceb487a | 134 | |
2003b7af FR |
135 | /* |
136 | * The actual disarming is done here on each CPU and synchronized using | |
137 | * stop_machine. This synchronization is necessary on SMP to avoid removing | |
138 | * a probe between the moment the 'Undefined Instruction' exception is raised | |
139 | * and the moment the exception handler reads the faulting instruction from | |
aceb487a JM |
140 | * memory. It is also needed to atomically set the two half-words of a 32-bit |
141 | * Thumb breakpoint. | |
2003b7af FR |
142 | */ |
143 | int __kprobes __arch_disarm_kprobe(void *p) | |
144 | { | |
145 | struct kprobe *kp = p; | |
b21d55e9 | 146 | void *addr = (void *)((uintptr_t)kp->addr & ~1); |
aceb487a | 147 | |
b21d55e9 | 148 | __patch_text(addr, kp->opcode); |
aceb487a | 149 | |
2003b7af FR |
150 | return 0; |
151 | } | |
152 | ||
24ba613c AS |
153 | void __kprobes arch_disarm_kprobe(struct kprobe *p) |
154 | { | |
0b5f9c00 | 155 | stop_machine(__arch_disarm_kprobe, p, cpu_online_mask); |
24ba613c AS |
156 | } |
157 | ||
158 | void __kprobes arch_remove_kprobe(struct kprobe *p) | |
159 | { | |
160 | if (p->ainsn.insn) { | |
24ba613c | 161 | free_insn_slot(p->ainsn.insn, 0); |
24ba613c AS |
162 | p->ainsn.insn = NULL; |
163 | } | |
164 | } | |
165 | ||
166 | static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb) | |
167 | { | |
168 | kcb->prev_kprobe.kp = kprobe_running(); | |
169 | kcb->prev_kprobe.status = kcb->kprobe_status; | |
170 | } | |
171 | ||
172 | static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb) | |
173 | { | |
174 | __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp; | |
175 | kcb->kprobe_status = kcb->prev_kprobe.status; | |
176 | } | |
177 | ||
178 | static void __kprobes set_current_kprobe(struct kprobe *p) | |
179 | { | |
180 | __get_cpu_var(current_kprobe) = p; | |
181 | } | |
182 | ||
3cca6c24 JM |
183 | static void __kprobes |
184 | singlestep_skip(struct kprobe *p, struct pt_regs *regs) | |
185 | { | |
186 | #ifdef CONFIG_THUMB2_KERNEL | |
187 | regs->ARM_cpsr = it_advance(regs->ARM_cpsr); | |
188 | if (is_wide_instruction(p->opcode)) | |
189 | regs->ARM_pc += 4; | |
190 | else | |
191 | regs->ARM_pc += 2; | |
192 | #else | |
193 | regs->ARM_pc += 4; | |
194 | #endif | |
195 | } | |
196 | ||
c6a7d97d JM |
197 | static inline void __kprobes |
198 | singlestep(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb) | |
24ba613c | 199 | { |
c6a7d97d | 200 | p->ainsn.insn_singlestep(p, regs); |
24ba613c AS |
201 | } |
202 | ||
203 | /* | |
204 | * Called with IRQs disabled. IRQs must remain disabled from that point | |
205 | * all the way until processing this kprobe is complete. The current | |
206 | * kprobes implementation cannot process more than one nested level of | |
207 | * kprobe, and that level is reserved for user kprobe handlers, so we can't | |
208 | * risk encountering a new kprobe in an interrupt handler. | |
209 | */ | |
210 | void __kprobes kprobe_handler(struct pt_regs *regs) | |
211 | { | |
212 | struct kprobe *p, *cur; | |
213 | struct kprobe_ctlblk *kcb; | |
24ba613c AS |
214 | |
215 | kcb = get_kprobe_ctlblk(); | |
216 | cur = kprobe_running(); | |
aceb487a JM |
217 | |
218 | #ifdef CONFIG_THUMB2_KERNEL | |
219 | /* | |
220 | * First look for a probe which was registered using an address with | |
221 | * bit 0 set, this is the usual situation for pointers to Thumb code. | |
222 | * If not found, fallback to looking for one with bit 0 clear. | |
223 | */ | |
224 | p = get_kprobe((kprobe_opcode_t *)(regs->ARM_pc | 1)); | |
225 | if (!p) | |
226 | p = get_kprobe((kprobe_opcode_t *)regs->ARM_pc); | |
227 | ||
228 | #else /* ! CONFIG_THUMB2_KERNEL */ | |
229 | p = get_kprobe((kprobe_opcode_t *)regs->ARM_pc); | |
230 | #endif | |
24ba613c AS |
231 | |
232 | if (p) { | |
233 | if (cur) { | |
234 | /* Kprobe is pending, so we're recursing. */ | |
235 | switch (kcb->kprobe_status) { | |
236 | case KPROBE_HIT_ACTIVE: | |
237 | case KPROBE_HIT_SSDONE: | |
238 | /* A pre- or post-handler probe got us here. */ | |
239 | kprobes_inc_nmissed_count(p); | |
240 | save_previous_kprobe(kcb); | |
241 | set_current_kprobe(p); | |
242 | kcb->kprobe_status = KPROBE_REENTER; | |
243 | singlestep(p, regs, kcb); | |
244 | restore_previous_kprobe(kcb); | |
245 | break; | |
246 | default: | |
247 | /* impossible cases */ | |
248 | BUG(); | |
249 | } | |
3cca6c24 JM |
250 | } else if (p->ainsn.insn_check_cc(regs->ARM_cpsr)) { |
251 | /* Probe hit and conditional execution check ok. */ | |
24ba613c AS |
252 | set_current_kprobe(p); |
253 | kcb->kprobe_status = KPROBE_HIT_ACTIVE; | |
254 | ||
255 | /* | |
256 | * If we have no pre-handler or it returned 0, we | |
257 | * continue with normal processing. If we have a | |
258 | * pre-handler and it returned non-zero, it prepped | |
259 | * for calling the break_handler below on re-entry, | |
260 | * so get out doing nothing more here. | |
261 | */ | |
262 | if (!p->pre_handler || !p->pre_handler(p, regs)) { | |
263 | kcb->kprobe_status = KPROBE_HIT_SS; | |
264 | singlestep(p, regs, kcb); | |
265 | if (p->post_handler) { | |
266 | kcb->kprobe_status = KPROBE_HIT_SSDONE; | |
267 | p->post_handler(p, regs, 0); | |
268 | } | |
269 | reset_current_kprobe(); | |
270 | } | |
3cca6c24 JM |
271 | } else { |
272 | /* | |
273 | * Probe hit but conditional execution check failed, | |
274 | * so just skip the instruction and continue as if | |
275 | * nothing had happened. | |
276 | */ | |
277 | singlestep_skip(p, regs); | |
24ba613c AS |
278 | } |
279 | } else if (cur) { | |
280 | /* We probably hit a jprobe. Call its break handler. */ | |
281 | if (cur->break_handler && cur->break_handler(cur, regs)) { | |
282 | kcb->kprobe_status = KPROBE_HIT_SS; | |
283 | singlestep(cur, regs, kcb); | |
284 | if (cur->post_handler) { | |
285 | kcb->kprobe_status = KPROBE_HIT_SSDONE; | |
286 | cur->post_handler(cur, regs, 0); | |
287 | } | |
288 | } | |
289 | reset_current_kprobe(); | |
290 | } else { | |
291 | /* | |
292 | * The probe was removed and a race is in progress. | |
293 | * There is nothing we can do about it. Let's restart | |
294 | * the instruction. By the time we can restart, the | |
295 | * real instruction will be there. | |
296 | */ | |
297 | } | |
298 | } | |
299 | ||
3305a607 | 300 | static int __kprobes kprobe_trap_handler(struct pt_regs *regs, unsigned int instr) |
24ba613c | 301 | { |
3305a607 NP |
302 | unsigned long flags; |
303 | local_irq_save(flags); | |
24ba613c | 304 | kprobe_handler(regs); |
3305a607 | 305 | local_irq_restore(flags); |
24ba613c AS |
306 | return 0; |
307 | } | |
308 | ||
309 | int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned int fsr) | |
310 | { | |
311 | struct kprobe *cur = kprobe_running(); | |
312 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
313 | ||
314 | switch (kcb->kprobe_status) { | |
315 | case KPROBE_HIT_SS: | |
316 | case KPROBE_REENTER: | |
317 | /* | |
318 | * We are here because the instruction being single | |
319 | * stepped caused a page fault. We reset the current | |
320 | * kprobe and the PC to point back to the probe address | |
321 | * and allow the page fault handler to continue as a | |
322 | * normal page fault. | |
323 | */ | |
324 | regs->ARM_pc = (long)cur->addr; | |
325 | if (kcb->kprobe_status == KPROBE_REENTER) { | |
326 | restore_previous_kprobe(kcb); | |
327 | } else { | |
328 | reset_current_kprobe(); | |
329 | } | |
330 | break; | |
331 | ||
332 | case KPROBE_HIT_ACTIVE: | |
333 | case KPROBE_HIT_SSDONE: | |
334 | /* | |
335 | * We increment the nmissed count for accounting, | |
336 | * we can also use npre/npostfault count for accounting | |
337 | * these specific fault cases. | |
338 | */ | |
339 | kprobes_inc_nmissed_count(cur); | |
340 | ||
341 | /* | |
342 | * We come here because instructions in the pre/post | |
343 | * handler caused the page_fault, this could happen | |
344 | * if handler tries to access user space by | |
345 | * copy_from_user(), get_user() etc. Let the | |
346 | * user-specified handler try to fix it. | |
347 | */ | |
348 | if (cur->fault_handler && cur->fault_handler(cur, regs, fsr)) | |
349 | return 1; | |
350 | break; | |
351 | ||
352 | default: | |
353 | break; | |
354 | } | |
355 | ||
356 | return 0; | |
357 | } | |
358 | ||
359 | int __kprobes kprobe_exceptions_notify(struct notifier_block *self, | |
360 | unsigned long val, void *data) | |
361 | { | |
362 | /* | |
363 | * notify_die() is currently never called on ARM, | |
364 | * so this callback is currently empty. | |
365 | */ | |
366 | return NOTIFY_DONE; | |
367 | } | |
368 | ||
369 | /* | |
370 | * When a retprobed function returns, trampoline_handler() is called, | |
371 | * calling the kretprobe's handler. We construct a struct pt_regs to | |
372 | * give a view of registers r0-r11 to the user return-handler. This is | |
373 | * not a complete pt_regs structure, but that should be plenty sufficient | |
374 | * for kretprobe handlers which should normally be interested in r0 only | |
375 | * anyway. | |
376 | */ | |
e0773410 | 377 | void __naked __kprobes kretprobe_trampoline(void) |
24ba613c AS |
378 | { |
379 | __asm__ __volatile__ ( | |
380 | "stmdb sp!, {r0 - r11} \n\t" | |
381 | "mov r0, sp \n\t" | |
382 | "bl trampoline_handler \n\t" | |
383 | "mov lr, r0 \n\t" | |
384 | "ldmia sp!, {r0 - r11} \n\t" | |
de419840 JM |
385 | #ifdef CONFIG_THUMB2_KERNEL |
386 | "bx lr \n\t" | |
387 | #else | |
24ba613c | 388 | "mov pc, lr \n\t" |
de419840 | 389 | #endif |
24ba613c AS |
390 | : : : "memory"); |
391 | } | |
392 | ||
393 | /* Called from kretprobe_trampoline */ | |
394 | static __used __kprobes void *trampoline_handler(struct pt_regs *regs) | |
395 | { | |
396 | struct kretprobe_instance *ri = NULL; | |
397 | struct hlist_head *head, empty_rp; | |
b67bfe0d | 398 | struct hlist_node *tmp; |
24ba613c AS |
399 | unsigned long flags, orig_ret_address = 0; |
400 | unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline; | |
401 | ||
402 | INIT_HLIST_HEAD(&empty_rp); | |
ef53d9c5 | 403 | kretprobe_hash_lock(current, &head, &flags); |
24ba613c AS |
404 | |
405 | /* | |
406 | * It is possible to have multiple instances associated with a given | |
407 | * task either because multiple functions in the call path have | |
408 | * a return probe installed on them, and/or more than one return | |
409 | * probe was registered for a target function. | |
410 | * | |
411 | * We can handle this because: | |
412 | * - instances are always inserted at the head of the list | |
413 | * - when multiple return probes are registered for the same | |
414 | * function, the first instance's ret_addr will point to the | |
415 | * real return address, and all the rest will point to | |
416 | * kretprobe_trampoline | |
417 | */ | |
b67bfe0d | 418 | hlist_for_each_entry_safe(ri, tmp, head, hlist) { |
24ba613c AS |
419 | if (ri->task != current) |
420 | /* another task is sharing our hash bucket */ | |
421 | continue; | |
422 | ||
423 | if (ri->rp && ri->rp->handler) { | |
424 | __get_cpu_var(current_kprobe) = &ri->rp->kp; | |
425 | get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE; | |
426 | ri->rp->handler(ri, regs); | |
427 | __get_cpu_var(current_kprobe) = NULL; | |
428 | } | |
429 | ||
430 | orig_ret_address = (unsigned long)ri->ret_addr; | |
431 | recycle_rp_inst(ri, &empty_rp); | |
432 | ||
433 | if (orig_ret_address != trampoline_address) | |
434 | /* | |
435 | * This is the real return address. Any other | |
436 | * instances associated with this task are for | |
437 | * other calls deeper on the call stack | |
438 | */ | |
439 | break; | |
440 | } | |
441 | ||
442 | kretprobe_assert(ri, orig_ret_address, trampoline_address); | |
ef53d9c5 | 443 | kretprobe_hash_unlock(current, &flags); |
24ba613c | 444 | |
b67bfe0d | 445 | hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { |
24ba613c AS |
446 | hlist_del(&ri->hlist); |
447 | kfree(ri); | |
448 | } | |
449 | ||
450 | return (void *)orig_ret_address; | |
451 | } | |
452 | ||
24ba613c AS |
453 | void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, |
454 | struct pt_regs *regs) | |
455 | { | |
456 | ri->ret_addr = (kprobe_opcode_t *)regs->ARM_lr; | |
457 | ||
458 | /* Replace the return addr with trampoline addr. */ | |
459 | regs->ARM_lr = (unsigned long)&kretprobe_trampoline; | |
460 | } | |
461 | ||
462 | int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) | |
463 | { | |
464 | struct jprobe *jp = container_of(p, struct jprobe, kp); | |
465 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
466 | long sp_addr = regs->ARM_sp; | |
de419840 | 467 | long cpsr; |
24ba613c AS |
468 | |
469 | kcb->jprobe_saved_regs = *regs; | |
470 | memcpy(kcb->jprobes_stack, (void *)sp_addr, MIN_STACK_SIZE(sp_addr)); | |
471 | regs->ARM_pc = (long)jp->entry; | |
de419840 JM |
472 | |
473 | cpsr = regs->ARM_cpsr | PSR_I_BIT; | |
474 | #ifdef CONFIG_THUMB2_KERNEL | |
475 | /* Set correct Thumb state in cpsr */ | |
476 | if (regs->ARM_pc & 1) | |
477 | cpsr |= PSR_T_BIT; | |
478 | else | |
479 | cpsr &= ~PSR_T_BIT; | |
480 | #endif | |
481 | regs->ARM_cpsr = cpsr; | |
482 | ||
24ba613c AS |
483 | preempt_disable(); |
484 | return 1; | |
485 | } | |
486 | ||
487 | void __kprobes jprobe_return(void) | |
488 | { | |
489 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
490 | ||
491 | __asm__ __volatile__ ( | |
492 | /* | |
493 | * Setup an empty pt_regs. Fill SP and PC fields as | |
494 | * they're needed by longjmp_break_handler. | |
782a0fd1 MW |
495 | * |
496 | * We allocate some slack between the original SP and start of | |
497 | * our fabricated regs. To be precise we want to have worst case | |
498 | * covered which is STMFD with all 16 regs so we allocate 2 * | |
499 | * sizeof(struct_pt_regs)). | |
500 | * | |
501 | * This is to prevent any simulated instruction from writing | |
502 | * over the regs when they are accessing the stack. | |
24ba613c | 503 | */ |
de419840 JM |
504 | #ifdef CONFIG_THUMB2_KERNEL |
505 | "sub r0, %0, %1 \n\t" | |
506 | "mov sp, r0 \n\t" | |
507 | #else | |
24ba613c | 508 | "sub sp, %0, %1 \n\t" |
de419840 | 509 | #endif |
24ba613c AS |
510 | "ldr r0, ="__stringify(JPROBE_MAGIC_ADDR)"\n\t" |
511 | "str %0, [sp, %2] \n\t" | |
512 | "str r0, [sp, %3] \n\t" | |
513 | "mov r0, sp \n\t" | |
514 | "bl kprobe_handler \n\t" | |
515 | ||
516 | /* | |
517 | * Return to the context saved by setjmp_pre_handler | |
518 | * and restored by longjmp_break_handler. | |
519 | */ | |
de419840 JM |
520 | #ifdef CONFIG_THUMB2_KERNEL |
521 | "ldr lr, [sp, %2] \n\t" /* lr = saved sp */ | |
522 | "ldrd r0, r1, [sp, %5] \n\t" /* r0,r1 = saved lr,pc */ | |
523 | "ldr r2, [sp, %4] \n\t" /* r2 = saved psr */ | |
524 | "stmdb lr!, {r0, r1, r2} \n\t" /* push saved lr and */ | |
525 | /* rfe context */ | |
526 | "ldmia sp, {r0 - r12} \n\t" | |
527 | "mov sp, lr \n\t" | |
528 | "ldr lr, [sp], #4 \n\t" | |
529 | "rfeia sp! \n\t" | |
530 | #else | |
24ba613c AS |
531 | "ldr r0, [sp, %4] \n\t" |
532 | "msr cpsr_cxsf, r0 \n\t" | |
533 | "ldmia sp, {r0 - pc} \n\t" | |
de419840 | 534 | #endif |
24ba613c AS |
535 | : |
536 | : "r" (kcb->jprobe_saved_regs.ARM_sp), | |
782a0fd1 | 537 | "I" (sizeof(struct pt_regs) * 2), |
24ba613c AS |
538 | "J" (offsetof(struct pt_regs, ARM_sp)), |
539 | "J" (offsetof(struct pt_regs, ARM_pc)), | |
de419840 JM |
540 | "J" (offsetof(struct pt_regs, ARM_cpsr)), |
541 | "J" (offsetof(struct pt_regs, ARM_lr)) | |
24ba613c AS |
542 | : "memory", "cc"); |
543 | } | |
544 | ||
545 | int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) | |
546 | { | |
547 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
548 | long stack_addr = kcb->jprobe_saved_regs.ARM_sp; | |
549 | long orig_sp = regs->ARM_sp; | |
550 | struct jprobe *jp = container_of(p, struct jprobe, kp); | |
551 | ||
552 | if (regs->ARM_pc == JPROBE_MAGIC_ADDR) { | |
553 | if (orig_sp != stack_addr) { | |
554 | struct pt_regs *saved_regs = | |
555 | (struct pt_regs *)kcb->jprobe_saved_regs.ARM_sp; | |
556 | printk("current sp %lx does not match saved sp %lx\n", | |
557 | orig_sp, stack_addr); | |
558 | printk("Saved registers for jprobe %p\n", jp); | |
559 | show_regs(saved_regs); | |
560 | printk("Current registers\n"); | |
561 | show_regs(regs); | |
562 | BUG(); | |
563 | } | |
564 | *regs = kcb->jprobe_saved_regs; | |
565 | memcpy((void *)stack_addr, kcb->jprobes_stack, | |
566 | MIN_STACK_SIZE(stack_addr)); | |
567 | preempt_enable_no_resched(); | |
568 | return 1; | |
569 | } | |
570 | return 0; | |
571 | } | |
572 | ||
b24061fa NP |
573 | int __kprobes arch_trampoline_kprobe(struct kprobe *p) |
574 | { | |
575 | return 0; | |
576 | } | |
577 | ||
aceb487a JM |
578 | #ifdef CONFIG_THUMB2_KERNEL |
579 | ||
580 | static struct undef_hook kprobes_thumb16_break_hook = { | |
581 | .instr_mask = 0xffff, | |
582 | .instr_val = KPROBE_THUMB16_BREAKPOINT_INSTRUCTION, | |
583 | .cpsr_mask = MODE_MASK, | |
584 | .cpsr_val = SVC_MODE, | |
585 | .fn = kprobe_trap_handler, | |
586 | }; | |
587 | ||
588 | static struct undef_hook kprobes_thumb32_break_hook = { | |
589 | .instr_mask = 0xffffffff, | |
590 | .instr_val = KPROBE_THUMB32_BREAKPOINT_INSTRUCTION, | |
591 | .cpsr_mask = MODE_MASK, | |
592 | .cpsr_val = SVC_MODE, | |
593 | .fn = kprobe_trap_handler, | |
594 | }; | |
595 | ||
596 | #else /* !CONFIG_THUMB2_KERNEL */ | |
597 | ||
598 | static struct undef_hook kprobes_arm_break_hook = { | |
3b269455 | 599 | .instr_mask = 0x0fffffff, |
aceb487a | 600 | .instr_val = KPROBE_ARM_BREAKPOINT_INSTRUCTION, |
24ba613c AS |
601 | .cpsr_mask = MODE_MASK, |
602 | .cpsr_val = SVC_MODE, | |
603 | .fn = kprobe_trap_handler, | |
604 | }; | |
605 | ||
aceb487a JM |
606 | #endif /* !CONFIG_THUMB2_KERNEL */ |
607 | ||
24ba613c AS |
608 | int __init arch_init_kprobes() |
609 | { | |
610 | arm_kprobe_decode_init(); | |
aceb487a JM |
611 | #ifdef CONFIG_THUMB2_KERNEL |
612 | register_undef_hook(&kprobes_thumb16_break_hook); | |
613 | register_undef_hook(&kprobes_thumb32_break_hook); | |
614 | #else | |
615 | register_undef_hook(&kprobes_arm_break_hook); | |
616 | #endif | |
24ba613c AS |
617 | return 0; |
618 | } |