Commit | Line | Data |
---|---|---|
2dd0e8d2 SP |
1 | /* |
2 | * arch/arm64/kernel/probes/kprobes.c | |
3 | * | |
4 | * Kprobes support for ARM64 | |
5 | * | |
6 | * Copyright (C) 2013 Linaro Limited. | |
7 | * Author: Sandeepa Prabhu <sandeepa.prabhu@linaro.org> | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License version 2 as | |
11 | * published by the Free Software Foundation. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | * General Public License for more details. | |
17 | * | |
18 | */ | |
19 | #include <linux/kernel.h> | |
20 | #include <linux/kprobes.h> | |
21 | #include <linux/module.h> | |
22 | #include <linux/slab.h> | |
23 | #include <linux/stop_machine.h> | |
24 | #include <linux/stringify.h> | |
25 | #include <asm/traps.h> | |
26 | #include <asm/ptrace.h> | |
27 | #include <asm/cacheflush.h> | |
28 | #include <asm/debug-monitors.h> | |
29 | #include <asm/system_misc.h> | |
30 | #include <asm/insn.h> | |
31 | #include <asm/uaccess.h> | |
32 | #include <asm/irq.h> | |
888b3c87 | 33 | #include <asm-generic/sections.h> |
2dd0e8d2 SP |
34 | |
35 | #include "decode-insn.h" | |
36 | ||
37 | #define MIN_STACK_SIZE(addr) (on_irq_stack(addr, raw_smp_processor_id()) ? \ | |
38 | min((unsigned long)IRQ_STACK_SIZE, \ | |
39 | IRQ_STACK_PTR(raw_smp_processor_id()) - (addr)) : \ | |
40 | min((unsigned long)MAX_STACK_SIZE, \ | |
41 | (unsigned long)current_thread_info() + THREAD_START_SP - (addr))) | |
42 | ||
43 | void jprobe_return_break(void); | |
44 | ||
45 | DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; | |
46 | DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); | |
47 | ||
39a67d49 SP |
48 | static void __kprobes |
49 | post_kprobe_handler(struct kprobe_ctlblk *, struct pt_regs *); | |
50 | ||
2dd0e8d2 SP |
51 | static void __kprobes arch_prepare_ss_slot(struct kprobe *p) |
52 | { | |
53 | /* prepare insn slot */ | |
54 | p->ainsn.insn[0] = cpu_to_le32(p->opcode); | |
55 | ||
56 | flush_icache_range((uintptr_t) (p->ainsn.insn), | |
57 | (uintptr_t) (p->ainsn.insn) + | |
58 | MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); | |
59 | ||
60 | /* | |
61 | * Needs restoring of return address after stepping xol. | |
62 | */ | |
63 | p->ainsn.restore = (unsigned long) p->addr + | |
64 | sizeof(kprobe_opcode_t); | |
65 | } | |
66 | ||
39a67d49 SP |
67 | static void __kprobes arch_prepare_simulate(struct kprobe *p) |
68 | { | |
69 | /* This instructions is not executed xol. No need to adjust the PC */ | |
70 | p->ainsn.restore = 0; | |
71 | } | |
72 | ||
73 | static void __kprobes arch_simulate_insn(struct kprobe *p, struct pt_regs *regs) | |
74 | { | |
75 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
76 | ||
77 | if (p->ainsn.handler) | |
78 | p->ainsn.handler((u32)p->opcode, (long)p->addr, regs); | |
79 | ||
80 | /* single step simulated, now go for post processing */ | |
81 | post_kprobe_handler(kcb, regs); | |
82 | } | |
83 | ||
2dd0e8d2 SP |
84 | int __kprobes arch_prepare_kprobe(struct kprobe *p) |
85 | { | |
86 | unsigned long probe_addr = (unsigned long)p->addr; | |
87 | extern char __start_rodata[]; | |
88 | extern char __end_rodata[]; | |
89 | ||
90 | if (probe_addr & 0x3) | |
91 | return -EINVAL; | |
92 | ||
93 | /* copy instruction */ | |
94 | p->opcode = le32_to_cpu(*p->addr); | |
95 | ||
96 | if (in_exception_text(probe_addr)) | |
97 | return -EINVAL; | |
98 | if (probe_addr >= (unsigned long) __start_rodata && | |
99 | probe_addr <= (unsigned long) __end_rodata) | |
100 | return -EINVAL; | |
101 | ||
102 | /* decode instruction */ | |
103 | switch (arm_kprobe_decode_insn(p->addr, &p->ainsn)) { | |
104 | case INSN_REJECTED: /* insn not supported */ | |
105 | return -EINVAL; | |
106 | ||
39a67d49 SP |
107 | case INSN_GOOD_NO_SLOT: /* insn need simulation */ |
108 | p->ainsn.insn = NULL; | |
109 | break; | |
110 | ||
2dd0e8d2 SP |
111 | case INSN_GOOD: /* instruction uses slot */ |
112 | p->ainsn.insn = get_insn_slot(); | |
113 | if (!p->ainsn.insn) | |
114 | return -ENOMEM; | |
115 | break; | |
116 | }; | |
117 | ||
118 | /* prepare the instruction */ | |
39a67d49 SP |
119 | if (p->ainsn.insn) |
120 | arch_prepare_ss_slot(p); | |
121 | else | |
122 | arch_prepare_simulate(p); | |
2dd0e8d2 SP |
123 | |
124 | return 0; | |
125 | } | |
126 | ||
127 | static int __kprobes patch_text(kprobe_opcode_t *addr, u32 opcode) | |
128 | { | |
129 | void *addrs[1]; | |
130 | u32 insns[1]; | |
131 | ||
132 | addrs[0] = (void *)addr; | |
133 | insns[0] = (u32)opcode; | |
134 | ||
135 | return aarch64_insn_patch_text(addrs, insns, 1); | |
136 | } | |
137 | ||
138 | /* arm kprobe: install breakpoint in text */ | |
139 | void __kprobes arch_arm_kprobe(struct kprobe *p) | |
140 | { | |
141 | patch_text(p->addr, BRK64_OPCODE_KPROBES); | |
142 | } | |
143 | ||
144 | /* disarm kprobe: remove breakpoint from text */ | |
145 | void __kprobes arch_disarm_kprobe(struct kprobe *p) | |
146 | { | |
147 | patch_text(p->addr, p->opcode); | |
148 | } | |
149 | ||
150 | void __kprobes arch_remove_kprobe(struct kprobe *p) | |
151 | { | |
152 | if (p->ainsn.insn) { | |
153 | free_insn_slot(p->ainsn.insn, 0); | |
154 | p->ainsn.insn = NULL; | |
155 | } | |
156 | } | |
157 | ||
158 | static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb) | |
159 | { | |
160 | kcb->prev_kprobe.kp = kprobe_running(); | |
161 | kcb->prev_kprobe.status = kcb->kprobe_status; | |
162 | } | |
163 | ||
164 | static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb) | |
165 | { | |
166 | __this_cpu_write(current_kprobe, kcb->prev_kprobe.kp); | |
167 | kcb->kprobe_status = kcb->prev_kprobe.status; | |
168 | } | |
169 | ||
170 | static void __kprobes set_current_kprobe(struct kprobe *p) | |
171 | { | |
172 | __this_cpu_write(current_kprobe, p); | |
173 | } | |
174 | ||
175 | /* | |
176 | * The D-flag (Debug mask) is set (masked) upon debug exception entry. | |
177 | * Kprobes needs to clear (unmask) D-flag -ONLY- in case of recursive | |
178 | * probe i.e. when probe hit from kprobe handler context upon | |
179 | * executing the pre/post handlers. In this case we return with | |
180 | * D-flag clear so that single-stepping can be carried-out. | |
181 | * | |
182 | * Leave D-flag set in all other cases. | |
183 | */ | |
184 | static void __kprobes | |
185 | spsr_set_debug_flag(struct pt_regs *regs, int mask) | |
186 | { | |
187 | unsigned long spsr = regs->pstate; | |
188 | ||
189 | if (mask) | |
190 | spsr |= PSR_D_BIT; | |
191 | else | |
192 | spsr &= ~PSR_D_BIT; | |
193 | ||
194 | regs->pstate = spsr; | |
195 | } | |
196 | ||
197 | /* | |
198 | * Interrupts need to be disabled before single-step mode is set, and not | |
199 | * reenabled until after single-step mode ends. | |
200 | * Without disabling interrupt on local CPU, there is a chance of | |
201 | * interrupt occurrence in the period of exception return and start of | |
202 | * out-of-line single-step, that result in wrongly single stepping | |
203 | * into the interrupt handler. | |
204 | */ | |
205 | static void __kprobes kprobes_save_local_irqflag(struct kprobe_ctlblk *kcb, | |
206 | struct pt_regs *regs) | |
207 | { | |
208 | kcb->saved_irqflag = regs->pstate; | |
209 | regs->pstate |= PSR_I_BIT; | |
210 | } | |
211 | ||
212 | static void __kprobes kprobes_restore_local_irqflag(struct kprobe_ctlblk *kcb, | |
213 | struct pt_regs *regs) | |
214 | { | |
215 | if (kcb->saved_irqflag & PSR_I_BIT) | |
216 | regs->pstate |= PSR_I_BIT; | |
217 | else | |
218 | regs->pstate &= ~PSR_I_BIT; | |
219 | } | |
220 | ||
221 | static void __kprobes | |
222 | set_ss_context(struct kprobe_ctlblk *kcb, unsigned long addr) | |
223 | { | |
224 | kcb->ss_ctx.ss_pending = true; | |
225 | kcb->ss_ctx.match_addr = addr + sizeof(kprobe_opcode_t); | |
226 | } | |
227 | ||
228 | static void __kprobes clear_ss_context(struct kprobe_ctlblk *kcb) | |
229 | { | |
230 | kcb->ss_ctx.ss_pending = false; | |
231 | kcb->ss_ctx.match_addr = 0; | |
232 | } | |
233 | ||
234 | static void __kprobes setup_singlestep(struct kprobe *p, | |
235 | struct pt_regs *regs, | |
236 | struct kprobe_ctlblk *kcb, int reenter) | |
237 | { | |
238 | unsigned long slot; | |
239 | ||
240 | if (reenter) { | |
241 | save_previous_kprobe(kcb); | |
242 | set_current_kprobe(p); | |
243 | kcb->kprobe_status = KPROBE_REENTER; | |
244 | } else { | |
245 | kcb->kprobe_status = KPROBE_HIT_SS; | |
246 | } | |
247 | ||
2dd0e8d2 | 248 | |
39a67d49 SP |
249 | if (p->ainsn.insn) { |
250 | /* prepare for single stepping */ | |
251 | slot = (unsigned long)p->ainsn.insn; | |
2dd0e8d2 | 252 | |
39a67d49 | 253 | set_ss_context(kcb, slot); /* mark pending ss */ |
2dd0e8d2 | 254 | |
39a67d49 SP |
255 | if (kcb->kprobe_status == KPROBE_REENTER) |
256 | spsr_set_debug_flag(regs, 0); | |
2dd0e8d2 | 257 | |
39a67d49 SP |
258 | /* IRQs and single stepping do not mix well. */ |
259 | kprobes_save_local_irqflag(kcb, regs); | |
260 | kernel_enable_single_step(regs); | |
261 | instruction_pointer_set(regs, slot); | |
262 | } else { | |
263 | /* insn simulation */ | |
264 | arch_simulate_insn(p, regs); | |
265 | } | |
2dd0e8d2 SP |
266 | } |
267 | ||
268 | static int __kprobes reenter_kprobe(struct kprobe *p, | |
269 | struct pt_regs *regs, | |
270 | struct kprobe_ctlblk *kcb) | |
271 | { | |
272 | switch (kcb->kprobe_status) { | |
273 | case KPROBE_HIT_SSDONE: | |
274 | case KPROBE_HIT_ACTIVE: | |
275 | kprobes_inc_nmissed_count(p); | |
276 | setup_singlestep(p, regs, kcb, 1); | |
277 | break; | |
278 | case KPROBE_HIT_SS: | |
279 | case KPROBE_REENTER: | |
280 | pr_warn("Unrecoverable kprobe detected at %p.\n", p->addr); | |
281 | dump_kprobe(p); | |
282 | BUG(); | |
283 | break; | |
284 | default: | |
285 | WARN_ON(1); | |
286 | return 0; | |
287 | } | |
288 | ||
289 | return 1; | |
290 | } | |
291 | ||
292 | static void __kprobes | |
293 | post_kprobe_handler(struct kprobe_ctlblk *kcb, struct pt_regs *regs) | |
294 | { | |
295 | struct kprobe *cur = kprobe_running(); | |
296 | ||
297 | if (!cur) | |
298 | return; | |
299 | ||
300 | /* return addr restore if non-branching insn */ | |
301 | if (cur->ainsn.restore != 0) | |
302 | instruction_pointer_set(regs, cur->ainsn.restore); | |
303 | ||
304 | /* restore back original saved kprobe variables and continue */ | |
305 | if (kcb->kprobe_status == KPROBE_REENTER) { | |
306 | restore_previous_kprobe(kcb); | |
307 | return; | |
308 | } | |
309 | /* call post handler */ | |
310 | kcb->kprobe_status = KPROBE_HIT_SSDONE; | |
311 | if (cur->post_handler) { | |
312 | /* post_handler can hit breakpoint and single step | |
313 | * again, so we enable D-flag for recursive exception. | |
314 | */ | |
315 | cur->post_handler(cur, regs, 0); | |
316 | } | |
317 | ||
318 | reset_current_kprobe(); | |
319 | } | |
320 | ||
321 | int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned int fsr) | |
322 | { | |
323 | struct kprobe *cur = kprobe_running(); | |
324 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
325 | ||
326 | switch (kcb->kprobe_status) { | |
327 | case KPROBE_HIT_SS: | |
328 | case KPROBE_REENTER: | |
329 | /* | |
330 | * We are here because the instruction being single | |
331 | * stepped caused a page fault. We reset the current | |
332 | * kprobe and the ip points back to the probe address | |
333 | * and allow the page fault handler to continue as a | |
334 | * normal page fault. | |
335 | */ | |
336 | instruction_pointer_set(regs, (unsigned long) cur->addr); | |
337 | if (!instruction_pointer(regs)) | |
338 | BUG(); | |
339 | ||
340 | kernel_disable_single_step(); | |
341 | if (kcb->kprobe_status == KPROBE_REENTER) | |
342 | spsr_set_debug_flag(regs, 1); | |
343 | ||
344 | if (kcb->kprobe_status == KPROBE_REENTER) | |
345 | restore_previous_kprobe(kcb); | |
346 | else | |
347 | reset_current_kprobe(); | |
348 | ||
349 | break; | |
350 | case KPROBE_HIT_ACTIVE: | |
351 | case KPROBE_HIT_SSDONE: | |
352 | /* | |
353 | * We increment the nmissed count for accounting, | |
354 | * we can also use npre/npostfault count for accounting | |
355 | * these specific fault cases. | |
356 | */ | |
357 | kprobes_inc_nmissed_count(cur); | |
358 | ||
359 | /* | |
360 | * We come here because instructions in the pre/post | |
361 | * handler caused the page_fault, this could happen | |
362 | * if handler tries to access user space by | |
363 | * copy_from_user(), get_user() etc. Let the | |
364 | * user-specified handler try to fix it first. | |
365 | */ | |
366 | if (cur->fault_handler && cur->fault_handler(cur, regs, fsr)) | |
367 | return 1; | |
368 | ||
369 | /* | |
370 | * In case the user-specified fault handler returned | |
371 | * zero, try to fix up. | |
372 | */ | |
373 | if (fixup_exception(regs)) | |
374 | return 1; | |
375 | } | |
376 | return 0; | |
377 | } | |
378 | ||
379 | int __kprobes kprobe_exceptions_notify(struct notifier_block *self, | |
380 | unsigned long val, void *data) | |
381 | { | |
382 | return NOTIFY_DONE; | |
383 | } | |
384 | ||
385 | static void __kprobes kprobe_handler(struct pt_regs *regs) | |
386 | { | |
387 | struct kprobe *p, *cur_kprobe; | |
388 | struct kprobe_ctlblk *kcb; | |
389 | unsigned long addr = instruction_pointer(regs); | |
390 | ||
391 | kcb = get_kprobe_ctlblk(); | |
392 | cur_kprobe = kprobe_running(); | |
393 | ||
394 | p = get_kprobe((kprobe_opcode_t *) addr); | |
395 | ||
396 | if (p) { | |
397 | if (cur_kprobe) { | |
398 | if (reenter_kprobe(p, regs, kcb)) | |
399 | return; | |
400 | } else { | |
401 | /* Probe hit */ | |
402 | set_current_kprobe(p); | |
403 | kcb->kprobe_status = KPROBE_HIT_ACTIVE; | |
404 | ||
405 | /* | |
406 | * If we have no pre-handler or it returned 0, we | |
407 | * continue with normal processing. If we have a | |
408 | * pre-handler and it returned non-zero, it prepped | |
409 | * for calling the break_handler below on re-entry, | |
410 | * so get out doing nothing more here. | |
411 | * | |
412 | * pre_handler can hit a breakpoint and can step thru | |
413 | * before return, keep PSTATE D-flag enabled until | |
414 | * pre_handler return back. | |
415 | */ | |
416 | if (!p->pre_handler || !p->pre_handler(p, regs)) { | |
417 | setup_singlestep(p, regs, kcb, 0); | |
418 | return; | |
419 | } | |
420 | } | |
421 | } else if ((le32_to_cpu(*(kprobe_opcode_t *) addr) == | |
422 | BRK64_OPCODE_KPROBES) && cur_kprobe) { | |
423 | /* We probably hit a jprobe. Call its break handler. */ | |
424 | if (cur_kprobe->break_handler && | |
425 | cur_kprobe->break_handler(cur_kprobe, regs)) { | |
426 | setup_singlestep(cur_kprobe, regs, kcb, 0); | |
427 | return; | |
428 | } | |
429 | } | |
430 | /* | |
431 | * The breakpoint instruction was removed right | |
432 | * after we hit it. Another cpu has removed | |
433 | * either a probepoint or a debugger breakpoint | |
434 | * at this address. In either case, no further | |
435 | * handling of this interrupt is appropriate. | |
436 | * Return back to original instruction, and continue. | |
437 | */ | |
438 | } | |
439 | ||
440 | static int __kprobes | |
441 | kprobe_ss_hit(struct kprobe_ctlblk *kcb, unsigned long addr) | |
442 | { | |
443 | if ((kcb->ss_ctx.ss_pending) | |
444 | && (kcb->ss_ctx.match_addr == addr)) { | |
445 | clear_ss_context(kcb); /* clear pending ss */ | |
446 | return DBG_HOOK_HANDLED; | |
447 | } | |
448 | /* not ours, kprobes should ignore it */ | |
449 | return DBG_HOOK_ERROR; | |
450 | } | |
451 | ||
452 | int __kprobes | |
453 | kprobe_single_step_handler(struct pt_regs *regs, unsigned int esr) | |
454 | { | |
455 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
456 | int retval; | |
457 | ||
458 | /* return error if this is not our step */ | |
459 | retval = kprobe_ss_hit(kcb, instruction_pointer(regs)); | |
460 | ||
461 | if (retval == DBG_HOOK_HANDLED) { | |
462 | kprobes_restore_local_irqflag(kcb, regs); | |
463 | kernel_disable_single_step(); | |
464 | ||
465 | if (kcb->kprobe_status == KPROBE_REENTER) | |
466 | spsr_set_debug_flag(regs, 1); | |
467 | ||
468 | post_kprobe_handler(kcb, regs); | |
469 | } | |
470 | ||
471 | return retval; | |
472 | } | |
473 | ||
474 | int __kprobes | |
475 | kprobe_breakpoint_handler(struct pt_regs *regs, unsigned int esr) | |
476 | { | |
477 | kprobe_handler(regs); | |
478 | return DBG_HOOK_HANDLED; | |
479 | } | |
480 | ||
481 | int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) | |
482 | { | |
483 | struct jprobe *jp = container_of(p, struct jprobe, kp); | |
484 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
485 | long stack_ptr = kernel_stack_pointer(regs); | |
486 | ||
487 | kcb->jprobe_saved_regs = *regs; | |
488 | /* | |
489 | * As Linus pointed out, gcc assumes that the callee | |
490 | * owns the argument space and could overwrite it, e.g. | |
491 | * tailcall optimization. So, to be absolutely safe | |
492 | * we also save and restore enough stack bytes to cover | |
493 | * the argument area. | |
494 | */ | |
495 | memcpy(kcb->jprobes_stack, (void *)stack_ptr, | |
496 | MIN_STACK_SIZE(stack_ptr)); | |
497 | ||
498 | instruction_pointer_set(regs, (unsigned long) jp->entry); | |
499 | preempt_disable(); | |
500 | pause_graph_tracing(); | |
501 | return 1; | |
502 | } | |
503 | ||
504 | void __kprobes jprobe_return(void) | |
505 | { | |
506 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
507 | ||
508 | /* | |
509 | * Jprobe handler return by entering break exception, | |
510 | * encoded same as kprobe, but with following conditions | |
511 | * -a magic number in x0 to identify from rest of other kprobes. | |
512 | * -restore stack addr to original saved pt_regs | |
513 | */ | |
514 | asm volatile ("ldr x0, [%0]\n\t" | |
515 | "mov sp, x0\n\t" | |
516 | ".globl jprobe_return_break\n\t" | |
517 | "jprobe_return_break:\n\t" | |
518 | "brk %1\n\t" | |
519 | : | |
520 | : "r"(&kcb->jprobe_saved_regs.sp), | |
521 | "I"(BRK64_ESR_KPROBES) | |
522 | : "memory"); | |
523 | } | |
524 | ||
525 | int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) | |
526 | { | |
527 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
528 | long stack_addr = kcb->jprobe_saved_regs.sp; | |
529 | long orig_sp = kernel_stack_pointer(regs); | |
530 | struct jprobe *jp = container_of(p, struct jprobe, kp); | |
531 | ||
532 | if (instruction_pointer(regs) != (u64) jprobe_return_break) | |
533 | return 0; | |
534 | ||
535 | if (orig_sp != stack_addr) { | |
536 | struct pt_regs *saved_regs = | |
537 | (struct pt_regs *)kcb->jprobe_saved_regs.sp; | |
538 | pr_err("current sp %lx does not match saved sp %lx\n", | |
539 | orig_sp, stack_addr); | |
540 | pr_err("Saved registers for jprobe %p\n", jp); | |
541 | show_regs(saved_regs); | |
542 | pr_err("Current registers\n"); | |
543 | show_regs(regs); | |
544 | BUG(); | |
545 | } | |
546 | unpause_graph_tracing(); | |
547 | *regs = kcb->jprobe_saved_regs; | |
548 | memcpy((void *)stack_addr, kcb->jprobes_stack, | |
549 | MIN_STACK_SIZE(stack_addr)); | |
550 | preempt_enable_no_resched(); | |
551 | return 1; | |
552 | } | |
553 | ||
888b3c87 PA |
554 | bool arch_within_kprobe_blacklist(unsigned long addr) |
555 | { | |
556 | extern char __idmap_text_start[], __idmap_text_end[]; | |
557 | extern char __hyp_idmap_text_start[], __hyp_idmap_text_end[]; | |
558 | ||
559 | if ((addr >= (unsigned long)__kprobes_text_start && | |
560 | addr < (unsigned long)__kprobes_text_end) || | |
561 | (addr >= (unsigned long)__entry_text_start && | |
562 | addr < (unsigned long)__entry_text_end) || | |
563 | (addr >= (unsigned long)__idmap_text_start && | |
564 | addr < (unsigned long)__idmap_text_end) || | |
565 | !!search_exception_tables(addr)) | |
566 | return true; | |
567 | ||
568 | if (!is_kernel_in_hyp_mode()) { | |
569 | if ((addr >= (unsigned long)__hyp_text_start && | |
570 | addr < (unsigned long)__hyp_text_end) || | |
571 | (addr >= (unsigned long)__hyp_idmap_text_start && | |
572 | addr < (unsigned long)__hyp_idmap_text_end)) | |
573 | return true; | |
574 | } | |
575 | ||
576 | return false; | |
577 | } | |
578 | ||
da6a9125 WC |
579 | void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs) |
580 | { | |
fcfd708b SP |
581 | struct kretprobe_instance *ri = NULL; |
582 | struct hlist_head *head, empty_rp; | |
583 | struct hlist_node *tmp; | |
584 | unsigned long flags, orig_ret_address = 0; | |
585 | unsigned long trampoline_address = | |
586 | (unsigned long)&kretprobe_trampoline; | |
587 | kprobe_opcode_t *correct_ret_addr = NULL; | |
588 | ||
589 | INIT_HLIST_HEAD(&empty_rp); | |
590 | kretprobe_hash_lock(current, &head, &flags); | |
591 | ||
592 | /* | |
593 | * It is possible to have multiple instances associated with a given | |
594 | * task either because multiple functions in the call path have | |
595 | * return probes installed on them, and/or more than one | |
596 | * return probe was registered for a target function. | |
597 | * | |
598 | * We can handle this because: | |
599 | * - instances are always pushed into the head of the list | |
600 | * - when multiple return probes are registered for the same | |
601 | * function, the (chronologically) first instance's ret_addr | |
602 | * will be the real return address, and all the rest will | |
603 | * point to kretprobe_trampoline. | |
604 | */ | |
605 | hlist_for_each_entry_safe(ri, tmp, head, hlist) { | |
606 | if (ri->task != current) | |
607 | /* another task is sharing our hash bucket */ | |
608 | continue; | |
609 | ||
610 | orig_ret_address = (unsigned long)ri->ret_addr; | |
611 | ||
612 | if (orig_ret_address != trampoline_address) | |
613 | /* | |
614 | * This is the real return address. Any other | |
615 | * instances associated with this task are for | |
616 | * other calls deeper on the call stack | |
617 | */ | |
618 | break; | |
619 | } | |
620 | ||
621 | kretprobe_assert(ri, orig_ret_address, trampoline_address); | |
622 | ||
623 | correct_ret_addr = ri->ret_addr; | |
624 | hlist_for_each_entry_safe(ri, tmp, head, hlist) { | |
625 | if (ri->task != current) | |
626 | /* another task is sharing our hash bucket */ | |
627 | continue; | |
628 | ||
629 | orig_ret_address = (unsigned long)ri->ret_addr; | |
630 | if (ri->rp && ri->rp->handler) { | |
631 | __this_cpu_write(current_kprobe, &ri->rp->kp); | |
632 | get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE; | |
633 | ri->ret_addr = correct_ret_addr; | |
634 | ri->rp->handler(ri, regs); | |
635 | __this_cpu_write(current_kprobe, NULL); | |
636 | } | |
637 | ||
638 | recycle_rp_inst(ri, &empty_rp); | |
639 | ||
640 | if (orig_ret_address != trampoline_address) | |
641 | /* | |
642 | * This is the real return address. Any other | |
643 | * instances associated with this task are for | |
644 | * other calls deeper on the call stack | |
645 | */ | |
646 | break; | |
647 | } | |
648 | ||
649 | kretprobe_hash_unlock(current, &flags); | |
650 | ||
651 | hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { | |
652 | hlist_del(&ri->hlist); | |
653 | kfree(ri); | |
654 | } | |
655 | return (void *)orig_ret_address; | |
656 | } | |
657 | ||
658 | void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, | |
659 | struct pt_regs *regs) | |
660 | { | |
661 | ri->ret_addr = (kprobe_opcode_t *)regs->regs[30]; | |
662 | ||
663 | /* replace return addr (x30) with trampoline */ | |
664 | regs->regs[30] = (long)&kretprobe_trampoline; | |
665 | } | |
666 | ||
667 | int __kprobes arch_trampoline_kprobe(struct kprobe *p) | |
668 | { | |
669 | return 0; | |
da6a9125 WC |
670 | } |
671 | ||
2dd0e8d2 SP |
672 | int __init arch_init_kprobes(void) |
673 | { | |
674 | return 0; | |
675 | } |