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1 | /* | |
2 | * Based on arch/arm/kernel/traps.c | |
3 | * | |
4 | * Copyright (C) 1995-2009 Russell King | |
5 | * Copyright (C) 2012 ARM Ltd. | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
18 | */ | |
19 | ||
20 | #include <linux/bug.h> | |
21 | #include <linux/signal.h> | |
22 | #include <linux/personality.h> | |
23 | #include <linux/kallsyms.h> | |
24 | #include <linux/spinlock.h> | |
25 | #include <linux/uaccess.h> | |
26 | #include <linux/hardirq.h> | |
27 | #include <linux/kdebug.h> | |
28 | #include <linux/module.h> | |
29 | #include <linux/kexec.h> | |
30 | #include <linux/delay.h> | |
31 | #include <linux/init.h> | |
32 | #include <linux/sched.h> | |
33 | #include <linux/syscalls.h> | |
34 | ||
35 | #include <asm/atomic.h> | |
36 | #include <asm/bug.h> | |
37 | #include <asm/debug-monitors.h> | |
38 | #include <asm/esr.h> | |
39 | #include <asm/insn.h> | |
40 | #include <asm/traps.h> | |
41 | #include <asm/stacktrace.h> | |
42 | #include <asm/exception.h> | |
43 | #include <asm/system_misc.h> | |
44 | ||
45 | static const char *handler[]= { | |
46 | "Synchronous Abort", | |
47 | "IRQ", | |
48 | "FIQ", | |
49 | "Error" | |
50 | }; | |
51 | ||
52 | int show_unhandled_signals = 1; | |
53 | ||
54 | /* | |
55 | * Dump out the contents of some memory nicely... | |
56 | */ | |
57 | static void dump_mem(const char *lvl, const char *str, unsigned long bottom, | |
58 | unsigned long top, bool compat) | |
59 | { | |
60 | unsigned long first; | |
61 | mm_segment_t fs; | |
62 | int i; | |
63 | unsigned int width = compat ? 4 : 8; | |
64 | ||
65 | /* | |
66 | * We need to switch to kernel mode so that we can use __get_user | |
67 | * to safely read from kernel space. Note that we now dump the | |
68 | * code first, just in case the backtrace kills us. | |
69 | */ | |
70 | fs = get_fs(); | |
71 | set_fs(KERNEL_DS); | |
72 | ||
73 | printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top); | |
74 | ||
75 | for (first = bottom & ~31; first < top; first += 32) { | |
76 | unsigned long p; | |
77 | char str[sizeof(" 12345678") * 8 + 1]; | |
78 | ||
79 | memset(str, ' ', sizeof(str)); | |
80 | str[sizeof(str) - 1] = '\0'; | |
81 | ||
82 | for (p = first, i = 0; i < (32 / width) | |
83 | && p < top; i++, p += width) { | |
84 | if (p >= bottom && p < top) { | |
85 | unsigned long val; | |
86 | ||
87 | if (width == 8) { | |
88 | if (__get_user(val, (unsigned long *)p) == 0) | |
89 | sprintf(str + i * 17, " %016lx", val); | |
90 | else | |
91 | sprintf(str + i * 17, " ????????????????"); | |
92 | } else { | |
93 | if (__get_user(val, (unsigned int *)p) == 0) | |
94 | sprintf(str + i * 9, " %08lx", val); | |
95 | else | |
96 | sprintf(str + i * 9, " ????????"); | |
97 | } | |
98 | } | |
99 | } | |
100 | printk("%s%04lx:%s\n", lvl, first & 0xffff, str); | |
101 | } | |
102 | ||
103 | set_fs(fs); | |
104 | } | |
105 | ||
106 | static void dump_backtrace_entry(unsigned long where) | |
107 | { | |
108 | /* | |
109 | * Note that 'where' can have a physical address, but it's not handled. | |
110 | */ | |
111 | print_ip_sym(where); | |
112 | } | |
113 | ||
114 | static void dump_instr(const char *lvl, struct pt_regs *regs) | |
115 | { | |
116 | unsigned long addr = instruction_pointer(regs); | |
117 | mm_segment_t fs; | |
118 | char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str; | |
119 | int i; | |
120 | ||
121 | /* | |
122 | * We need to switch to kernel mode so that we can use __get_user | |
123 | * to safely read from kernel space. Note that we now dump the | |
124 | * code first, just in case the backtrace kills us. | |
125 | */ | |
126 | fs = get_fs(); | |
127 | set_fs(KERNEL_DS); | |
128 | ||
129 | for (i = -4; i < 1; i++) { | |
130 | unsigned int val, bad; | |
131 | ||
132 | bad = __get_user(val, &((u32 *)addr)[i]); | |
133 | ||
134 | if (!bad) | |
135 | p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val); | |
136 | else { | |
137 | p += sprintf(p, "bad PC value"); | |
138 | break; | |
139 | } | |
140 | } | |
141 | printk("%sCode: %s\n", lvl, str); | |
142 | ||
143 | set_fs(fs); | |
144 | } | |
145 | ||
146 | static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) | |
147 | { | |
148 | struct stackframe frame; | |
149 | ||
150 | pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk); | |
151 | ||
152 | if (!tsk) | |
153 | tsk = current; | |
154 | ||
155 | if (regs) { | |
156 | frame.fp = regs->regs[29]; | |
157 | frame.sp = regs->sp; | |
158 | frame.pc = regs->pc; | |
159 | } else if (tsk == current) { | |
160 | frame.fp = (unsigned long)__builtin_frame_address(0); | |
161 | frame.sp = current_stack_pointer; | |
162 | frame.pc = (unsigned long)dump_backtrace; | |
163 | } else { | |
164 | /* | |
165 | * task blocked in __switch_to | |
166 | */ | |
167 | frame.fp = thread_saved_fp(tsk); | |
168 | frame.sp = thread_saved_sp(tsk); | |
169 | frame.pc = thread_saved_pc(tsk); | |
170 | } | |
171 | ||
172 | pr_emerg("Call trace:\n"); | |
173 | while (1) { | |
174 | unsigned long where = frame.pc; | |
175 | unsigned long stack; | |
176 | int ret; | |
177 | ||
178 | dump_backtrace_entry(where); | |
179 | ret = unwind_frame(&frame); | |
180 | if (ret < 0) | |
181 | break; | |
182 | stack = frame.sp; | |
183 | if (in_exception_text(where)) | |
184 | dump_mem("", "Exception stack", stack, | |
185 | stack + sizeof(struct pt_regs), false); | |
186 | } | |
187 | } | |
188 | ||
189 | void show_stack(struct task_struct *tsk, unsigned long *sp) | |
190 | { | |
191 | dump_backtrace(NULL, tsk); | |
192 | barrier(); | |
193 | } | |
194 | ||
195 | #ifdef CONFIG_PREEMPT | |
196 | #define S_PREEMPT " PREEMPT" | |
197 | #else | |
198 | #define S_PREEMPT "" | |
199 | #endif | |
200 | #define S_SMP " SMP" | |
201 | ||
202 | static int __die(const char *str, int err, struct thread_info *thread, | |
203 | struct pt_regs *regs) | |
204 | { | |
205 | struct task_struct *tsk = thread->task; | |
206 | static int die_counter; | |
207 | int ret; | |
208 | ||
209 | pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n", | |
210 | str, err, ++die_counter); | |
211 | ||
212 | /* trap and error numbers are mostly meaningless on ARM */ | |
213 | ret = notify_die(DIE_OOPS, str, regs, err, 0, SIGSEGV); | |
214 | if (ret == NOTIFY_STOP) | |
215 | return ret; | |
216 | ||
217 | print_modules(); | |
218 | __show_regs(regs); | |
219 | pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n", | |
220 | TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1); | |
221 | ||
222 | if (!user_mode(regs) || in_interrupt()) { | |
223 | dump_mem(KERN_EMERG, "Stack: ", regs->sp, | |
224 | THREAD_SIZE + (unsigned long)task_stack_page(tsk), | |
225 | compat_user_mode(regs)); | |
226 | dump_backtrace(regs, tsk); | |
227 | dump_instr(KERN_EMERG, regs); | |
228 | } | |
229 | ||
230 | return ret; | |
231 | } | |
232 | ||
233 | static DEFINE_RAW_SPINLOCK(die_lock); | |
234 | ||
235 | /* | |
236 | * This function is protected against re-entrancy. | |
237 | */ | |
238 | void die(const char *str, struct pt_regs *regs, int err) | |
239 | { | |
240 | struct thread_info *thread = current_thread_info(); | |
241 | int ret; | |
242 | ||
243 | oops_enter(); | |
244 | ||
245 | raw_spin_lock_irq(&die_lock); | |
246 | console_verbose(); | |
247 | bust_spinlocks(1); | |
248 | ret = __die(str, err, thread, regs); | |
249 | ||
250 | if (regs && kexec_should_crash(thread->task)) | |
251 | crash_kexec(regs); | |
252 | ||
253 | bust_spinlocks(0); | |
254 | add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); | |
255 | raw_spin_unlock_irq(&die_lock); | |
256 | oops_exit(); | |
257 | ||
258 | if (in_interrupt()) | |
259 | panic("Fatal exception in interrupt"); | |
260 | if (panic_on_oops) | |
261 | panic("Fatal exception"); | |
262 | if (ret != NOTIFY_STOP) | |
263 | do_exit(SIGSEGV); | |
264 | } | |
265 | ||
266 | void arm64_notify_die(const char *str, struct pt_regs *regs, | |
267 | struct siginfo *info, int err) | |
268 | { | |
269 | if (user_mode(regs)) { | |
270 | current->thread.fault_address = 0; | |
271 | current->thread.fault_code = err; | |
272 | force_sig_info(info->si_signo, info, current); | |
273 | } else { | |
274 | die(str, regs, err); | |
275 | } | |
276 | } | |
277 | ||
278 | static LIST_HEAD(undef_hook); | |
279 | static DEFINE_RAW_SPINLOCK(undef_lock); | |
280 | ||
281 | void register_undef_hook(struct undef_hook *hook) | |
282 | { | |
283 | unsigned long flags; | |
284 | ||
285 | raw_spin_lock_irqsave(&undef_lock, flags); | |
286 | list_add(&hook->node, &undef_hook); | |
287 | raw_spin_unlock_irqrestore(&undef_lock, flags); | |
288 | } | |
289 | ||
290 | void unregister_undef_hook(struct undef_hook *hook) | |
291 | { | |
292 | unsigned long flags; | |
293 | ||
294 | raw_spin_lock_irqsave(&undef_lock, flags); | |
295 | list_del(&hook->node); | |
296 | raw_spin_unlock_irqrestore(&undef_lock, flags); | |
297 | } | |
298 | ||
299 | static int call_undef_hook(struct pt_regs *regs) | |
300 | { | |
301 | struct undef_hook *hook; | |
302 | unsigned long flags; | |
303 | u32 instr; | |
304 | int (*fn)(struct pt_regs *regs, u32 instr) = NULL; | |
305 | void __user *pc = (void __user *)instruction_pointer(regs); | |
306 | ||
307 | if (!user_mode(regs)) | |
308 | return 1; | |
309 | ||
310 | if (compat_thumb_mode(regs)) { | |
311 | /* 16-bit Thumb instruction */ | |
312 | if (get_user(instr, (u16 __user *)pc)) | |
313 | goto exit; | |
314 | instr = le16_to_cpu(instr); | |
315 | if (aarch32_insn_is_wide(instr)) { | |
316 | u32 instr2; | |
317 | ||
318 | if (get_user(instr2, (u16 __user *)(pc + 2))) | |
319 | goto exit; | |
320 | instr2 = le16_to_cpu(instr2); | |
321 | instr = (instr << 16) | instr2; | |
322 | } | |
323 | } else { | |
324 | /* 32-bit ARM instruction */ | |
325 | if (get_user(instr, (u32 __user *)pc)) | |
326 | goto exit; | |
327 | instr = le32_to_cpu(instr); | |
328 | } | |
329 | ||
330 | raw_spin_lock_irqsave(&undef_lock, flags); | |
331 | list_for_each_entry(hook, &undef_hook, node) | |
332 | if ((instr & hook->instr_mask) == hook->instr_val && | |
333 | (regs->pstate & hook->pstate_mask) == hook->pstate_val) | |
334 | fn = hook->fn; | |
335 | ||
336 | raw_spin_unlock_irqrestore(&undef_lock, flags); | |
337 | exit: | |
338 | return fn ? fn(regs, instr) : 1; | |
339 | } | |
340 | ||
341 | asmlinkage void __exception do_undefinstr(struct pt_regs *regs) | |
342 | { | |
343 | siginfo_t info; | |
344 | void __user *pc = (void __user *)instruction_pointer(regs); | |
345 | ||
346 | /* check for AArch32 breakpoint instructions */ | |
347 | if (!aarch32_break_handler(regs)) | |
348 | return; | |
349 | ||
350 | if (call_undef_hook(regs) == 0) | |
351 | return; | |
352 | ||
353 | if (unhandled_signal(current, SIGILL) && show_unhandled_signals_ratelimited()) { | |
354 | pr_info("%s[%d]: undefined instruction: pc=%p\n", | |
355 | current->comm, task_pid_nr(current), pc); | |
356 | dump_instr(KERN_INFO, regs); | |
357 | } | |
358 | ||
359 | info.si_signo = SIGILL; | |
360 | info.si_errno = 0; | |
361 | info.si_code = ILL_ILLOPC; | |
362 | info.si_addr = pc; | |
363 | ||
364 | arm64_notify_die("Oops - undefined instruction", regs, &info, 0); | |
365 | } | |
366 | ||
367 | long compat_arm_syscall(struct pt_regs *regs); | |
368 | ||
369 | asmlinkage long do_ni_syscall(struct pt_regs *regs) | |
370 | { | |
371 | #ifdef CONFIG_COMPAT | |
372 | long ret; | |
373 | if (is_compat_task()) { | |
374 | ret = compat_arm_syscall(regs); | |
375 | if (ret != -ENOSYS) | |
376 | return ret; | |
377 | } | |
378 | #endif | |
379 | ||
380 | if (show_unhandled_signals_ratelimited()) { | |
381 | pr_info("%s[%d]: syscall %d\n", current->comm, | |
382 | task_pid_nr(current), (int)regs->syscallno); | |
383 | dump_instr("", regs); | |
384 | if (user_mode(regs)) | |
385 | __show_regs(regs); | |
386 | } | |
387 | ||
388 | return sys_ni_syscall(); | |
389 | } | |
390 | ||
391 | static const char *esr_class_str[] = { | |
392 | [0 ... ESR_ELx_EC_MAX] = "UNRECOGNIZED EC", | |
393 | [ESR_ELx_EC_UNKNOWN] = "Unknown/Uncategorized", | |
394 | [ESR_ELx_EC_WFx] = "WFI/WFE", | |
395 | [ESR_ELx_EC_CP15_32] = "CP15 MCR/MRC", | |
396 | [ESR_ELx_EC_CP15_64] = "CP15 MCRR/MRRC", | |
397 | [ESR_ELx_EC_CP14_MR] = "CP14 MCR/MRC", | |
398 | [ESR_ELx_EC_CP14_LS] = "CP14 LDC/STC", | |
399 | [ESR_ELx_EC_FP_ASIMD] = "ASIMD", | |
400 | [ESR_ELx_EC_CP10_ID] = "CP10 MRC/VMRS", | |
401 | [ESR_ELx_EC_CP14_64] = "CP14 MCRR/MRRC", | |
402 | [ESR_ELx_EC_ILL] = "PSTATE.IL", | |
403 | [ESR_ELx_EC_SVC32] = "SVC (AArch32)", | |
404 | [ESR_ELx_EC_HVC32] = "HVC (AArch32)", | |
405 | [ESR_ELx_EC_SMC32] = "SMC (AArch32)", | |
406 | [ESR_ELx_EC_SVC64] = "SVC (AArch64)", | |
407 | [ESR_ELx_EC_HVC64] = "HVC (AArch64)", | |
408 | [ESR_ELx_EC_SMC64] = "SMC (AArch64)", | |
409 | [ESR_ELx_EC_SYS64] = "MSR/MRS (AArch64)", | |
410 | [ESR_ELx_EC_IMP_DEF] = "EL3 IMP DEF", | |
411 | [ESR_ELx_EC_IABT_LOW] = "IABT (lower EL)", | |
412 | [ESR_ELx_EC_IABT_CUR] = "IABT (current EL)", | |
413 | [ESR_ELx_EC_PC_ALIGN] = "PC Alignment", | |
414 | [ESR_ELx_EC_DABT_LOW] = "DABT (lower EL)", | |
415 | [ESR_ELx_EC_DABT_CUR] = "DABT (current EL)", | |
416 | [ESR_ELx_EC_SP_ALIGN] = "SP Alignment", | |
417 | [ESR_ELx_EC_FP_EXC32] = "FP (AArch32)", | |
418 | [ESR_ELx_EC_FP_EXC64] = "FP (AArch64)", | |
419 | [ESR_ELx_EC_SERROR] = "SError", | |
420 | [ESR_ELx_EC_BREAKPT_LOW] = "Breakpoint (lower EL)", | |
421 | [ESR_ELx_EC_BREAKPT_CUR] = "Breakpoint (current EL)", | |
422 | [ESR_ELx_EC_SOFTSTP_LOW] = "Software Step (lower EL)", | |
423 | [ESR_ELx_EC_SOFTSTP_CUR] = "Software Step (current EL)", | |
424 | [ESR_ELx_EC_WATCHPT_LOW] = "Watchpoint (lower EL)", | |
425 | [ESR_ELx_EC_WATCHPT_CUR] = "Watchpoint (current EL)", | |
426 | [ESR_ELx_EC_BKPT32] = "BKPT (AArch32)", | |
427 | [ESR_ELx_EC_VECTOR32] = "Vector catch (AArch32)", | |
428 | [ESR_ELx_EC_BRK64] = "BRK (AArch64)", | |
429 | }; | |
430 | ||
431 | const char *esr_get_class_string(u32 esr) | |
432 | { | |
433 | return esr_class_str[esr >> ESR_ELx_EC_SHIFT]; | |
434 | } | |
435 | ||
436 | /* | |
437 | * bad_mode handles the impossible case in the exception vector. | |
438 | */ | |
439 | asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr) | |
440 | { | |
441 | siginfo_t info; | |
442 | void __user *pc = (void __user *)instruction_pointer(regs); | |
443 | console_verbose(); | |
444 | ||
445 | pr_crit("Bad mode in %s handler detected, code 0x%08x -- %s\n", | |
446 | handler[reason], esr, esr_get_class_string(esr)); | |
447 | __show_regs(regs); | |
448 | ||
449 | info.si_signo = SIGILL; | |
450 | info.si_errno = 0; | |
451 | info.si_code = ILL_ILLOPC; | |
452 | info.si_addr = pc; | |
453 | ||
454 | arm64_notify_die("Oops - bad mode", regs, &info, 0); | |
455 | } | |
456 | ||
457 | void __pte_error(const char *file, int line, unsigned long val) | |
458 | { | |
459 | pr_crit("%s:%d: bad pte %016lx.\n", file, line, val); | |
460 | } | |
461 | ||
462 | void __pmd_error(const char *file, int line, unsigned long val) | |
463 | { | |
464 | pr_crit("%s:%d: bad pmd %016lx.\n", file, line, val); | |
465 | } | |
466 | ||
467 | void __pud_error(const char *file, int line, unsigned long val) | |
468 | { | |
469 | pr_crit("%s:%d: bad pud %016lx.\n", file, line, val); | |
470 | } | |
471 | ||
472 | void __pgd_error(const char *file, int line, unsigned long val) | |
473 | { | |
474 | pr_crit("%s:%d: bad pgd %016lx.\n", file, line, val); | |
475 | } | |
476 | ||
477 | /* GENERIC_BUG traps */ | |
478 | ||
479 | int is_valid_bugaddr(unsigned long addr) | |
480 | { | |
481 | /* | |
482 | * bug_handler() only called for BRK #BUG_BRK_IMM. | |
483 | * So the answer is trivial -- any spurious instances with no | |
484 | * bug table entry will be rejected by report_bug() and passed | |
485 | * back to the debug-monitors code and handled as a fatal | |
486 | * unexpected debug exception. | |
487 | */ | |
488 | return 1; | |
489 | } | |
490 | ||
491 | static int bug_handler(struct pt_regs *regs, unsigned int esr) | |
492 | { | |
493 | if (user_mode(regs)) | |
494 | return DBG_HOOK_ERROR; | |
495 | ||
496 | switch (report_bug(regs->pc, regs)) { | |
497 | case BUG_TRAP_TYPE_BUG: | |
498 | die("Oops - BUG", regs, 0); | |
499 | break; | |
500 | ||
501 | case BUG_TRAP_TYPE_WARN: | |
502 | /* Ideally, report_bug() should backtrace for us... but no. */ | |
503 | dump_backtrace(regs, NULL); | |
504 | break; | |
505 | ||
506 | default: | |
507 | /* unknown/unrecognised bug trap type */ | |
508 | return DBG_HOOK_ERROR; | |
509 | } | |
510 | ||
511 | /* If thread survives, skip over the BUG instruction and continue: */ | |
512 | regs->pc += AARCH64_INSN_SIZE; /* skip BRK and resume */ | |
513 | return DBG_HOOK_HANDLED; | |
514 | } | |
515 | ||
516 | static struct break_hook bug_break_hook = { | |
517 | .esr_val = 0xf2000000 | BUG_BRK_IMM, | |
518 | .esr_mask = 0xffffffff, | |
519 | .fn = bug_handler, | |
520 | }; | |
521 | ||
522 | /* | |
523 | * Initial handler for AArch64 BRK exceptions | |
524 | * This handler only used until debug_traps_init(). | |
525 | */ | |
526 | int __init early_brk64(unsigned long addr, unsigned int esr, | |
527 | struct pt_regs *regs) | |
528 | { | |
529 | return bug_handler(regs, esr) != DBG_HOOK_HANDLED; | |
530 | } | |
531 | ||
532 | /* This registration must happen early, before debug_traps_init(). */ | |
533 | void __init trap_init(void) | |
534 | { | |
535 | register_break_hook(&bug_break_hook); | |
536 | } |