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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 | */ | |
f7e35c5b | 19 | #include <linux/kasan.h> |
2dd0e8d2 SP |
20 | #include <linux/kernel.h> |
21 | #include <linux/kprobes.h> | |
0edfa839 | 22 | #include <linux/extable.h> |
2dd0e8d2 SP |
23 | #include <linux/slab.h> |
24 | #include <linux/stop_machine.h> | |
25 | #include <linux/stringify.h> | |
26 | #include <asm/traps.h> | |
27 | #include <asm/ptrace.h> | |
28 | #include <asm/cacheflush.h> | |
29 | #include <asm/debug-monitors.h> | |
30 | #include <asm/system_misc.h> | |
31 | #include <asm/insn.h> | |
7c0f6ba6 | 32 | #include <linux/uaccess.h> |
2dd0e8d2 | 33 | #include <asm/irq.h> |
ee78fdc7 | 34 | #include <asm/sections.h> |
2dd0e8d2 SP |
35 | |
36 | #include "decode-insn.h" | |
37 | ||
2dd0e8d2 SP |
38 | DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; |
39 | DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); | |
40 | ||
39a67d49 SP |
41 | static void __kprobes |
42 | post_kprobe_handler(struct kprobe_ctlblk *, struct pt_regs *); | |
43 | ||
2dd0e8d2 SP |
44 | static void __kprobes arch_prepare_ss_slot(struct kprobe *p) |
45 | { | |
46 | /* prepare insn slot */ | |
c2249707 | 47 | p->ainsn.api.insn[0] = cpu_to_le32(p->opcode); |
2dd0e8d2 | 48 | |
c2249707 PA |
49 | flush_icache_range((uintptr_t) (p->ainsn.api.insn), |
50 | (uintptr_t) (p->ainsn.api.insn) + | |
2dd0e8d2 SP |
51 | MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); |
52 | ||
53 | /* | |
54 | * Needs restoring of return address after stepping xol. | |
55 | */ | |
c2249707 | 56 | p->ainsn.api.restore = (unsigned long) p->addr + |
2dd0e8d2 SP |
57 | sizeof(kprobe_opcode_t); |
58 | } | |
59 | ||
39a67d49 SP |
60 | static void __kprobes arch_prepare_simulate(struct kprobe *p) |
61 | { | |
62 | /* This instructions is not executed xol. No need to adjust the PC */ | |
c2249707 | 63 | p->ainsn.api.restore = 0; |
39a67d49 SP |
64 | } |
65 | ||
66 | static void __kprobes arch_simulate_insn(struct kprobe *p, struct pt_regs *regs) | |
67 | { | |
68 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
69 | ||
c2249707 PA |
70 | if (p->ainsn.api.handler) |
71 | p->ainsn.api.handler((u32)p->opcode, (long)p->addr, regs); | |
39a67d49 SP |
72 | |
73 | /* single step simulated, now go for post processing */ | |
74 | post_kprobe_handler(kcb, regs); | |
75 | } | |
76 | ||
2dd0e8d2 SP |
77 | int __kprobes arch_prepare_kprobe(struct kprobe *p) |
78 | { | |
79 | unsigned long probe_addr = (unsigned long)p->addr; | |
80 | extern char __start_rodata[]; | |
81 | extern char __end_rodata[]; | |
82 | ||
83 | if (probe_addr & 0x3) | |
84 | return -EINVAL; | |
85 | ||
86 | /* copy instruction */ | |
87 | p->opcode = le32_to_cpu(*p->addr); | |
88 | ||
89 | if (in_exception_text(probe_addr)) | |
90 | return -EINVAL; | |
91 | if (probe_addr >= (unsigned long) __start_rodata && | |
92 | probe_addr <= (unsigned long) __end_rodata) | |
93 | return -EINVAL; | |
94 | ||
95 | /* decode instruction */ | |
96 | switch (arm_kprobe_decode_insn(p->addr, &p->ainsn)) { | |
97 | case INSN_REJECTED: /* insn not supported */ | |
98 | return -EINVAL; | |
99 | ||
39a67d49 | 100 | case INSN_GOOD_NO_SLOT: /* insn need simulation */ |
c2249707 | 101 | p->ainsn.api.insn = NULL; |
39a67d49 SP |
102 | break; |
103 | ||
2dd0e8d2 | 104 | case INSN_GOOD: /* instruction uses slot */ |
c2249707 PA |
105 | p->ainsn.api.insn = get_insn_slot(); |
106 | if (!p->ainsn.api.insn) | |
2dd0e8d2 SP |
107 | return -ENOMEM; |
108 | break; | |
109 | }; | |
110 | ||
111 | /* prepare the instruction */ | |
c2249707 | 112 | if (p->ainsn.api.insn) |
39a67d49 SP |
113 | arch_prepare_ss_slot(p); |
114 | else | |
115 | arch_prepare_simulate(p); | |
2dd0e8d2 SP |
116 | |
117 | return 0; | |
118 | } | |
119 | ||
120 | static int __kprobes patch_text(kprobe_opcode_t *addr, u32 opcode) | |
121 | { | |
122 | void *addrs[1]; | |
123 | u32 insns[1]; | |
124 | ||
125 | addrs[0] = (void *)addr; | |
126 | insns[0] = (u32)opcode; | |
127 | ||
128 | return aarch64_insn_patch_text(addrs, insns, 1); | |
129 | } | |
130 | ||
131 | /* arm kprobe: install breakpoint in text */ | |
132 | void __kprobes arch_arm_kprobe(struct kprobe *p) | |
133 | { | |
134 | patch_text(p->addr, BRK64_OPCODE_KPROBES); | |
135 | } | |
136 | ||
137 | /* disarm kprobe: remove breakpoint from text */ | |
138 | void __kprobes arch_disarm_kprobe(struct kprobe *p) | |
139 | { | |
140 | patch_text(p->addr, p->opcode); | |
141 | } | |
142 | ||
143 | void __kprobes arch_remove_kprobe(struct kprobe *p) | |
144 | { | |
c2249707 PA |
145 | if (p->ainsn.api.insn) { |
146 | free_insn_slot(p->ainsn.api.insn, 0); | |
147 | p->ainsn.api.insn = NULL; | |
2dd0e8d2 SP |
148 | } |
149 | } | |
150 | ||
151 | static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb) | |
152 | { | |
153 | kcb->prev_kprobe.kp = kprobe_running(); | |
154 | kcb->prev_kprobe.status = kcb->kprobe_status; | |
155 | } | |
156 | ||
157 | static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb) | |
158 | { | |
159 | __this_cpu_write(current_kprobe, kcb->prev_kprobe.kp); | |
160 | kcb->kprobe_status = kcb->prev_kprobe.status; | |
161 | } | |
162 | ||
163 | static void __kprobes set_current_kprobe(struct kprobe *p) | |
164 | { | |
165 | __this_cpu_write(current_kprobe, p); | |
166 | } | |
167 | ||
168 | /* | |
7419333f PA |
169 | * When PSTATE.D is set (masked), then software step exceptions can not be |
170 | * generated. | |
171 | * SPSR's D bit shows the value of PSTATE.D immediately before the | |
172 | * exception was taken. PSTATE.D is set while entering into any exception | |
173 | * mode, however software clears it for any normal (none-debug-exception) | |
174 | * mode in the exception entry. Therefore, when we are entering into kprobe | |
175 | * breakpoint handler from any normal mode then SPSR.D bit is already | |
176 | * cleared, however it is set when we are entering from any debug exception | |
177 | * mode. | |
178 | * Since we always need to generate single step exception after a kprobe | |
179 | * breakpoint exception therefore we need to clear it unconditionally, when | |
180 | * we become sure that the current breakpoint exception is for kprobe. | |
2dd0e8d2 SP |
181 | */ |
182 | static void __kprobes | |
183 | spsr_set_debug_flag(struct pt_regs *regs, int mask) | |
184 | { | |
185 | unsigned long spsr = regs->pstate; | |
186 | ||
187 | if (mask) | |
188 | spsr |= PSR_D_BIT; | |
189 | else | |
190 | spsr &= ~PSR_D_BIT; | |
191 | ||
192 | regs->pstate = spsr; | |
193 | } | |
194 | ||
195 | /* | |
196 | * Interrupts need to be disabled before single-step mode is set, and not | |
197 | * reenabled until after single-step mode ends. | |
198 | * Without disabling interrupt on local CPU, there is a chance of | |
199 | * interrupt occurrence in the period of exception return and start of | |
200 | * out-of-line single-step, that result in wrongly single stepping | |
201 | * into the interrupt handler. | |
202 | */ | |
203 | static void __kprobes kprobes_save_local_irqflag(struct kprobe_ctlblk *kcb, | |
204 | struct pt_regs *regs) | |
205 | { | |
206 | kcb->saved_irqflag = regs->pstate; | |
207 | regs->pstate |= PSR_I_BIT; | |
208 | } | |
209 | ||
210 | static void __kprobes kprobes_restore_local_irqflag(struct kprobe_ctlblk *kcb, | |
211 | struct pt_regs *regs) | |
212 | { | |
213 | if (kcb->saved_irqflag & PSR_I_BIT) | |
214 | regs->pstate |= PSR_I_BIT; | |
215 | else | |
216 | regs->pstate &= ~PSR_I_BIT; | |
217 | } | |
218 | ||
219 | static void __kprobes | |
220 | set_ss_context(struct kprobe_ctlblk *kcb, unsigned long addr) | |
221 | { | |
222 | kcb->ss_ctx.ss_pending = true; | |
223 | kcb->ss_ctx.match_addr = addr + sizeof(kprobe_opcode_t); | |
224 | } | |
225 | ||
226 | static void __kprobes clear_ss_context(struct kprobe_ctlblk *kcb) | |
227 | { | |
228 | kcb->ss_ctx.ss_pending = false; | |
229 | kcb->ss_ctx.match_addr = 0; | |
230 | } | |
231 | ||
232 | static void __kprobes setup_singlestep(struct kprobe *p, | |
233 | struct pt_regs *regs, | |
234 | struct kprobe_ctlblk *kcb, int reenter) | |
235 | { | |
236 | unsigned long slot; | |
237 | ||
238 | if (reenter) { | |
239 | save_previous_kprobe(kcb); | |
240 | set_current_kprobe(p); | |
241 | kcb->kprobe_status = KPROBE_REENTER; | |
242 | } else { | |
243 | kcb->kprobe_status = KPROBE_HIT_SS; | |
244 | } | |
245 | ||
2dd0e8d2 | 246 | |
c2249707 | 247 | if (p->ainsn.api.insn) { |
39a67d49 | 248 | /* prepare for single stepping */ |
c2249707 | 249 | slot = (unsigned long)p->ainsn.api.insn; |
2dd0e8d2 | 250 | |
39a67d49 | 251 | set_ss_context(kcb, slot); /* mark pending ss */ |
2dd0e8d2 | 252 | |
7419333f | 253 | spsr_set_debug_flag(regs, 0); |
2dd0e8d2 | 254 | |
39a67d49 SP |
255 | /* IRQs and single stepping do not mix well. */ |
256 | kprobes_save_local_irqflag(kcb, regs); | |
257 | kernel_enable_single_step(regs); | |
258 | instruction_pointer_set(regs, slot); | |
259 | } else { | |
260 | /* insn simulation */ | |
261 | arch_simulate_insn(p, regs); | |
262 | } | |
2dd0e8d2 SP |
263 | } |
264 | ||
265 | static int __kprobes reenter_kprobe(struct kprobe *p, | |
266 | struct pt_regs *regs, | |
267 | struct kprobe_ctlblk *kcb) | |
268 | { | |
269 | switch (kcb->kprobe_status) { | |
270 | case KPROBE_HIT_SSDONE: | |
271 | case KPROBE_HIT_ACTIVE: | |
272 | kprobes_inc_nmissed_count(p); | |
273 | setup_singlestep(p, regs, kcb, 1); | |
274 | break; | |
275 | case KPROBE_HIT_SS: | |
276 | case KPROBE_REENTER: | |
277 | pr_warn("Unrecoverable kprobe detected at %p.\n", p->addr); | |
278 | dump_kprobe(p); | |
279 | BUG(); | |
280 | break; | |
281 | default: | |
282 | WARN_ON(1); | |
283 | return 0; | |
284 | } | |
285 | ||
286 | return 1; | |
287 | } | |
288 | ||
289 | static void __kprobes | |
290 | post_kprobe_handler(struct kprobe_ctlblk *kcb, struct pt_regs *regs) | |
291 | { | |
292 | struct kprobe *cur = kprobe_running(); | |
293 | ||
294 | if (!cur) | |
295 | return; | |
296 | ||
297 | /* return addr restore if non-branching insn */ | |
c2249707 PA |
298 | if (cur->ainsn.api.restore != 0) |
299 | instruction_pointer_set(regs, cur->ainsn.api.restore); | |
2dd0e8d2 SP |
300 | |
301 | /* restore back original saved kprobe variables and continue */ | |
302 | if (kcb->kprobe_status == KPROBE_REENTER) { | |
303 | restore_previous_kprobe(kcb); | |
304 | return; | |
305 | } | |
306 | /* call post handler */ | |
307 | kcb->kprobe_status = KPROBE_HIT_SSDONE; | |
308 | if (cur->post_handler) { | |
309 | /* post_handler can hit breakpoint and single step | |
310 | * again, so we enable D-flag for recursive exception. | |
311 | */ | |
312 | cur->post_handler(cur, regs, 0); | |
313 | } | |
314 | ||
315 | reset_current_kprobe(); | |
316 | } | |
317 | ||
318 | int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned int fsr) | |
319 | { | |
320 | struct kprobe *cur = kprobe_running(); | |
321 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
322 | ||
323 | switch (kcb->kprobe_status) { | |
324 | case KPROBE_HIT_SS: | |
325 | case KPROBE_REENTER: | |
326 | /* | |
327 | * We are here because the instruction being single | |
328 | * stepped caused a page fault. We reset the current | |
329 | * kprobe and the ip points back to the probe address | |
330 | * and allow the page fault handler to continue as a | |
331 | * normal page fault. | |
332 | */ | |
333 | instruction_pointer_set(regs, (unsigned long) cur->addr); | |
334 | if (!instruction_pointer(regs)) | |
335 | BUG(); | |
336 | ||
337 | kernel_disable_single_step(); | |
2dd0e8d2 SP |
338 | |
339 | if (kcb->kprobe_status == KPROBE_REENTER) | |
340 | restore_previous_kprobe(kcb); | |
341 | else | |
342 | reset_current_kprobe(); | |
343 | ||
344 | break; | |
345 | case KPROBE_HIT_ACTIVE: | |
346 | case KPROBE_HIT_SSDONE: | |
347 | /* | |
348 | * We increment the nmissed count for accounting, | |
349 | * we can also use npre/npostfault count for accounting | |
350 | * these specific fault cases. | |
351 | */ | |
352 | kprobes_inc_nmissed_count(cur); | |
353 | ||
354 | /* | |
355 | * We come here because instructions in the pre/post | |
356 | * handler caused the page_fault, this could happen | |
357 | * if handler tries to access user space by | |
358 | * copy_from_user(), get_user() etc. Let the | |
359 | * user-specified handler try to fix it first. | |
360 | */ | |
361 | if (cur->fault_handler && cur->fault_handler(cur, regs, fsr)) | |
362 | return 1; | |
363 | ||
364 | /* | |
365 | * In case the user-specified fault handler returned | |
366 | * zero, try to fix up. | |
367 | */ | |
368 | if (fixup_exception(regs)) | |
369 | return 1; | |
370 | } | |
371 | return 0; | |
372 | } | |
373 | ||
374 | int __kprobes kprobe_exceptions_notify(struct notifier_block *self, | |
375 | unsigned long val, void *data) | |
376 | { | |
377 | return NOTIFY_DONE; | |
378 | } | |
379 | ||
380 | static void __kprobes kprobe_handler(struct pt_regs *regs) | |
381 | { | |
382 | struct kprobe *p, *cur_kprobe; | |
383 | struct kprobe_ctlblk *kcb; | |
384 | unsigned long addr = instruction_pointer(regs); | |
385 | ||
386 | kcb = get_kprobe_ctlblk(); | |
387 | cur_kprobe = kprobe_running(); | |
388 | ||
389 | p = get_kprobe((kprobe_opcode_t *) addr); | |
390 | ||
391 | if (p) { | |
392 | if (cur_kprobe) { | |
393 | if (reenter_kprobe(p, regs, kcb)) | |
394 | return; | |
395 | } else { | |
396 | /* Probe hit */ | |
397 | set_current_kprobe(p); | |
398 | kcb->kprobe_status = KPROBE_HIT_ACTIVE; | |
399 | ||
400 | /* | |
401 | * If we have no pre-handler or it returned 0, we | |
402 | * continue with normal processing. If we have a | |
403 | * pre-handler and it returned non-zero, it prepped | |
404 | * for calling the break_handler below on re-entry, | |
405 | * so get out doing nothing more here. | |
406 | * | |
407 | * pre_handler can hit a breakpoint and can step thru | |
408 | * before return, keep PSTATE D-flag enabled until | |
409 | * pre_handler return back. | |
410 | */ | |
411 | if (!p->pre_handler || !p->pre_handler(p, regs)) { | |
412 | setup_singlestep(p, regs, kcb, 0); | |
413 | return; | |
414 | } | |
415 | } | |
416 | } else if ((le32_to_cpu(*(kprobe_opcode_t *) addr) == | |
417 | BRK64_OPCODE_KPROBES) && cur_kprobe) { | |
418 | /* We probably hit a jprobe. Call its break handler. */ | |
419 | if (cur_kprobe->break_handler && | |
420 | cur_kprobe->break_handler(cur_kprobe, regs)) { | |
421 | setup_singlestep(cur_kprobe, regs, kcb, 0); | |
422 | return; | |
423 | } | |
424 | } | |
425 | /* | |
426 | * The breakpoint instruction was removed right | |
427 | * after we hit it. Another cpu has removed | |
428 | * either a probepoint or a debugger breakpoint | |
429 | * at this address. In either case, no further | |
430 | * handling of this interrupt is appropriate. | |
431 | * Return back to original instruction, and continue. | |
432 | */ | |
433 | } | |
434 | ||
435 | static int __kprobes | |
436 | kprobe_ss_hit(struct kprobe_ctlblk *kcb, unsigned long addr) | |
437 | { | |
438 | if ((kcb->ss_ctx.ss_pending) | |
439 | && (kcb->ss_ctx.match_addr == addr)) { | |
440 | clear_ss_context(kcb); /* clear pending ss */ | |
441 | return DBG_HOOK_HANDLED; | |
442 | } | |
443 | /* not ours, kprobes should ignore it */ | |
444 | return DBG_HOOK_ERROR; | |
445 | } | |
446 | ||
447 | int __kprobes | |
448 | kprobe_single_step_handler(struct pt_regs *regs, unsigned int esr) | |
449 | { | |
450 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
451 | int retval; | |
452 | ||
453 | /* return error if this is not our step */ | |
454 | retval = kprobe_ss_hit(kcb, instruction_pointer(regs)); | |
455 | ||
456 | if (retval == DBG_HOOK_HANDLED) { | |
457 | kprobes_restore_local_irqflag(kcb, regs); | |
458 | kernel_disable_single_step(); | |
459 | ||
2dd0e8d2 SP |
460 | post_kprobe_handler(kcb, regs); |
461 | } | |
462 | ||
463 | return retval; | |
464 | } | |
465 | ||
466 | int __kprobes | |
467 | kprobe_breakpoint_handler(struct pt_regs *regs, unsigned int esr) | |
468 | { | |
469 | kprobe_handler(regs); | |
470 | return DBG_HOOK_HANDLED; | |
471 | } | |
472 | ||
473 | int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) | |
474 | { | |
475 | struct jprobe *jp = container_of(p, struct jprobe, kp); | |
476 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
2dd0e8d2 SP |
477 | |
478 | kcb->jprobe_saved_regs = *regs; | |
479 | /* | |
ad05711c DL |
480 | * Since we can't be sure where in the stack frame "stacked" |
481 | * pass-by-value arguments are stored we just don't try to | |
482 | * duplicate any of the stack. Do not use jprobes on functions that | |
483 | * use more than 64 bytes (after padding each to an 8 byte boundary) | |
484 | * of arguments, or pass individual arguments larger than 16 bytes. | |
2dd0e8d2 | 485 | */ |
2dd0e8d2 SP |
486 | |
487 | instruction_pointer_set(regs, (unsigned long) jp->entry); | |
488 | preempt_disable(); | |
489 | pause_graph_tracing(); | |
490 | return 1; | |
491 | } | |
492 | ||
493 | void __kprobes jprobe_return(void) | |
494 | { | |
495 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
496 | ||
497 | /* | |
498 | * Jprobe handler return by entering break exception, | |
499 | * encoded same as kprobe, but with following conditions | |
3b7d14e9 | 500 | * -a special PC to identify it from the other kprobes. |
2dd0e8d2 SP |
501 | * -restore stack addr to original saved pt_regs |
502 | */ | |
3b7d14e9 MZ |
503 | asm volatile(" mov sp, %0 \n" |
504 | "jprobe_return_break: brk %1 \n" | |
505 | : | |
506 | : "r" (kcb->jprobe_saved_regs.sp), | |
507 | "I" (BRK64_ESR_KPROBES) | |
508 | : "memory"); | |
509 | ||
510 | unreachable(); | |
2dd0e8d2 SP |
511 | } |
512 | ||
513 | int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) | |
514 | { | |
515 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
516 | long stack_addr = kcb->jprobe_saved_regs.sp; | |
517 | long orig_sp = kernel_stack_pointer(regs); | |
518 | struct jprobe *jp = container_of(p, struct jprobe, kp); | |
3b7d14e9 | 519 | extern const char jprobe_return_break[]; |
2dd0e8d2 SP |
520 | |
521 | if (instruction_pointer(regs) != (u64) jprobe_return_break) | |
522 | return 0; | |
523 | ||
524 | if (orig_sp != stack_addr) { | |
525 | struct pt_regs *saved_regs = | |
526 | (struct pt_regs *)kcb->jprobe_saved_regs.sp; | |
527 | pr_err("current sp %lx does not match saved sp %lx\n", | |
528 | orig_sp, stack_addr); | |
529 | pr_err("Saved registers for jprobe %p\n", jp); | |
530 | show_regs(saved_regs); | |
531 | pr_err("Current registers\n"); | |
532 | show_regs(regs); | |
533 | BUG(); | |
534 | } | |
535 | unpause_graph_tracing(); | |
536 | *regs = kcb->jprobe_saved_regs; | |
2dd0e8d2 SP |
537 | preempt_enable_no_resched(); |
538 | return 1; | |
539 | } | |
540 | ||
888b3c87 PA |
541 | bool arch_within_kprobe_blacklist(unsigned long addr) |
542 | { | |
888b3c87 PA |
543 | if ((addr >= (unsigned long)__kprobes_text_start && |
544 | addr < (unsigned long)__kprobes_text_end) || | |
545 | (addr >= (unsigned long)__entry_text_start && | |
546 | addr < (unsigned long)__entry_text_end) || | |
547 | (addr >= (unsigned long)__idmap_text_start && | |
548 | addr < (unsigned long)__idmap_text_end) || | |
549 | !!search_exception_tables(addr)) | |
550 | return true; | |
551 | ||
552 | if (!is_kernel_in_hyp_mode()) { | |
553 | if ((addr >= (unsigned long)__hyp_text_start && | |
554 | addr < (unsigned long)__hyp_text_end) || | |
555 | (addr >= (unsigned long)__hyp_idmap_text_start && | |
556 | addr < (unsigned long)__hyp_idmap_text_end)) | |
557 | return true; | |
558 | } | |
559 | ||
560 | return false; | |
561 | } | |
562 | ||
da6a9125 WC |
563 | void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs) |
564 | { | |
fcfd708b SP |
565 | struct kretprobe_instance *ri = NULL; |
566 | struct hlist_head *head, empty_rp; | |
567 | struct hlist_node *tmp; | |
568 | unsigned long flags, orig_ret_address = 0; | |
569 | unsigned long trampoline_address = | |
570 | (unsigned long)&kretprobe_trampoline; | |
571 | kprobe_opcode_t *correct_ret_addr = NULL; | |
572 | ||
573 | INIT_HLIST_HEAD(&empty_rp); | |
574 | kretprobe_hash_lock(current, &head, &flags); | |
575 | ||
576 | /* | |
577 | * It is possible to have multiple instances associated with a given | |
578 | * task either because multiple functions in the call path have | |
579 | * return probes installed on them, and/or more than one | |
580 | * return probe was registered for a target function. | |
581 | * | |
582 | * We can handle this because: | |
583 | * - instances are always pushed into the head of the list | |
584 | * - when multiple return probes are registered for the same | |
585 | * function, the (chronologically) first instance's ret_addr | |
586 | * will be the real return address, and all the rest will | |
587 | * point to kretprobe_trampoline. | |
588 | */ | |
589 | hlist_for_each_entry_safe(ri, tmp, head, hlist) { | |
590 | if (ri->task != current) | |
591 | /* another task is sharing our hash bucket */ | |
592 | continue; | |
593 | ||
594 | orig_ret_address = (unsigned long)ri->ret_addr; | |
595 | ||
596 | if (orig_ret_address != trampoline_address) | |
597 | /* | |
598 | * This is the real return address. Any other | |
599 | * instances associated with this task are for | |
600 | * other calls deeper on the call stack | |
601 | */ | |
602 | break; | |
603 | } | |
604 | ||
605 | kretprobe_assert(ri, orig_ret_address, trampoline_address); | |
606 | ||
607 | correct_ret_addr = ri->ret_addr; | |
608 | hlist_for_each_entry_safe(ri, tmp, head, hlist) { | |
609 | if (ri->task != current) | |
610 | /* another task is sharing our hash bucket */ | |
611 | continue; | |
612 | ||
613 | orig_ret_address = (unsigned long)ri->ret_addr; | |
614 | if (ri->rp && ri->rp->handler) { | |
615 | __this_cpu_write(current_kprobe, &ri->rp->kp); | |
616 | get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE; | |
617 | ri->ret_addr = correct_ret_addr; | |
618 | ri->rp->handler(ri, regs); | |
619 | __this_cpu_write(current_kprobe, NULL); | |
620 | } | |
621 | ||
622 | recycle_rp_inst(ri, &empty_rp); | |
623 | ||
624 | if (orig_ret_address != trampoline_address) | |
625 | /* | |
626 | * This is the real return address. Any other | |
627 | * instances associated with this task are for | |
628 | * other calls deeper on the call stack | |
629 | */ | |
630 | break; | |
631 | } | |
632 | ||
633 | kretprobe_hash_unlock(current, &flags); | |
634 | ||
635 | hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { | |
636 | hlist_del(&ri->hlist); | |
637 | kfree(ri); | |
638 | } | |
639 | return (void *)orig_ret_address; | |
640 | } | |
641 | ||
642 | void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, | |
643 | struct pt_regs *regs) | |
644 | { | |
645 | ri->ret_addr = (kprobe_opcode_t *)regs->regs[30]; | |
646 | ||
647 | /* replace return addr (x30) with trampoline */ | |
648 | regs->regs[30] = (long)&kretprobe_trampoline; | |
649 | } | |
650 | ||
651 | int __kprobes arch_trampoline_kprobe(struct kprobe *p) | |
652 | { | |
653 | return 0; | |
da6a9125 WC |
654 | } |
655 | ||
2dd0e8d2 SP |
656 | int __init arch_init_kprobes(void) |
657 | { | |
658 | return 0; | |
659 | } |