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arm64: fix for bad_mode() handler to always result in panic
[mirror_ubuntu-focal-kernel.git] / arch / arm64 / kernel / traps.c
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/signal.h>
33 #include <linux/sched/debug.h>
34 #include <linux/sched/task_stack.h>
35 #include <linux/sizes.h>
36 #include <linux/syscalls.h>
37 #include <linux/mm_types.h>
38
39 #include <asm/atomic.h>
40 #include <asm/bug.h>
41 #include <asm/cpufeature.h>
42 #include <asm/daifflags.h>
43 #include <asm/debug-monitors.h>
44 #include <asm/esr.h>
45 #include <asm/insn.h>
46 #include <asm/traps.h>
47 #include <asm/smp.h>
48 #include <asm/stack_pointer.h>
49 #include <asm/stacktrace.h>
50 #include <asm/exception.h>
51 #include <asm/system_misc.h>
52 #include <asm/sysreg.h>
53
54 static const char *handler[]= {
55 "Synchronous Abort",
56 "IRQ",
57 "FIQ",
58 "Error"
59 };
60
61 int show_unhandled_signals = 0;
62
63 static void dump_backtrace_entry(unsigned long where)
64 {
65 printk(" %pS\n", (void *)where);
66 }
67
68 static void __dump_instr(const char *lvl, struct pt_regs *regs)
69 {
70 unsigned long addr = instruction_pointer(regs);
71 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
72 int i;
73
74 for (i = -4; i < 1; i++) {
75 unsigned int val, bad;
76
77 bad = get_user(val, &((u32 *)addr)[i]);
78
79 if (!bad)
80 p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
81 else {
82 p += sprintf(p, "bad PC value");
83 break;
84 }
85 }
86 printk("%sCode: %s\n", lvl, str);
87 }
88
89 static void dump_instr(const char *lvl, struct pt_regs *regs)
90 {
91 if (!user_mode(regs)) {
92 mm_segment_t fs = get_fs();
93 set_fs(KERNEL_DS);
94 __dump_instr(lvl, regs);
95 set_fs(fs);
96 } else {
97 __dump_instr(lvl, regs);
98 }
99 }
100
101 void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
102 {
103 struct stackframe frame;
104 int skip;
105
106 pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
107
108 if (!tsk)
109 tsk = current;
110
111 if (!try_get_task_stack(tsk))
112 return;
113
114 if (tsk == current) {
115 frame.fp = (unsigned long)__builtin_frame_address(0);
116 frame.pc = (unsigned long)dump_backtrace;
117 } else {
118 /*
119 * task blocked in __switch_to
120 */
121 frame.fp = thread_saved_fp(tsk);
122 frame.pc = thread_saved_pc(tsk);
123 }
124 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
125 frame.graph = tsk->curr_ret_stack;
126 #endif
127
128 skip = !!regs;
129 printk("Call trace:\n");
130 do {
131 /* skip until specified stack frame */
132 if (!skip) {
133 dump_backtrace_entry(frame.pc);
134 } else if (frame.fp == regs->regs[29]) {
135 skip = 0;
136 /*
137 * Mostly, this is the case where this function is
138 * called in panic/abort. As exception handler's
139 * stack frame does not contain the corresponding pc
140 * at which an exception has taken place, use regs->pc
141 * instead.
142 */
143 dump_backtrace_entry(regs->pc);
144 }
145 } while (!unwind_frame(tsk, &frame));
146
147 put_task_stack(tsk);
148 }
149
150 void show_stack(struct task_struct *tsk, unsigned long *sp)
151 {
152 dump_backtrace(NULL, tsk);
153 barrier();
154 }
155
156 #ifdef CONFIG_PREEMPT
157 #define S_PREEMPT " PREEMPT"
158 #else
159 #define S_PREEMPT ""
160 #endif
161 #define S_SMP " SMP"
162
163 static int __die(const char *str, int err, struct pt_regs *regs)
164 {
165 struct task_struct *tsk = current;
166 static int die_counter;
167 int ret;
168
169 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
170 str, err, ++die_counter);
171
172 /* trap and error numbers are mostly meaningless on ARM */
173 ret = notify_die(DIE_OOPS, str, regs, err, 0, SIGSEGV);
174 if (ret == NOTIFY_STOP)
175 return ret;
176
177 print_modules();
178 __show_regs(regs);
179 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
180 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk),
181 end_of_stack(tsk));
182
183 if (!user_mode(regs)) {
184 dump_backtrace(regs, tsk);
185 dump_instr(KERN_EMERG, regs);
186 }
187
188 return ret;
189 }
190
191 static DEFINE_RAW_SPINLOCK(die_lock);
192
193 /*
194 * This function is protected against re-entrancy.
195 */
196 void die(const char *str, struct pt_regs *regs, int err)
197 {
198 int ret;
199 unsigned long flags;
200
201 raw_spin_lock_irqsave(&die_lock, flags);
202
203 oops_enter();
204
205 console_verbose();
206 bust_spinlocks(1);
207 ret = __die(str, err, regs);
208
209 if (regs && kexec_should_crash(current))
210 crash_kexec(regs);
211
212 bust_spinlocks(0);
213 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
214 oops_exit();
215
216 if (in_interrupt())
217 panic("Fatal exception in interrupt");
218 if (panic_on_oops)
219 panic("Fatal exception");
220
221 raw_spin_unlock_irqrestore(&die_lock, flags);
222
223 if (ret != NOTIFY_STOP)
224 do_exit(SIGSEGV);
225 }
226
227 static bool show_unhandled_signals_ratelimited(void)
228 {
229 static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL,
230 DEFAULT_RATELIMIT_BURST);
231 return show_unhandled_signals && __ratelimit(&rs);
232 }
233
234 void arm64_force_sig_info(struct siginfo *info, const char *str,
235 struct task_struct *tsk)
236 {
237 unsigned int esr = tsk->thread.fault_code;
238 struct pt_regs *regs = task_pt_regs(tsk);
239
240 if (!unhandled_signal(tsk, info->si_signo))
241 goto send_sig;
242
243 if (!show_unhandled_signals_ratelimited())
244 goto send_sig;
245
246 pr_info("%s[%d]: unhandled exception: ", tsk->comm, task_pid_nr(tsk));
247 if (esr)
248 pr_cont("%s, ESR 0x%08x, ", esr_get_class_string(esr), esr);
249
250 pr_cont("%s", str);
251 print_vma_addr(KERN_CONT " in ", regs->pc);
252 pr_cont("\n");
253 __show_regs(regs);
254
255 send_sig:
256 force_sig_info(info->si_signo, info, tsk);
257 }
258
259 void arm64_notify_die(const char *str, struct pt_regs *regs,
260 struct siginfo *info, int err)
261 {
262 if (user_mode(regs)) {
263 WARN_ON(regs != current_pt_regs());
264 current->thread.fault_address = 0;
265 current->thread.fault_code = err;
266 arm64_force_sig_info(info, str, current);
267 } else {
268 die(str, regs, err);
269 }
270 }
271
272 void arm64_skip_faulting_instruction(struct pt_regs *regs, unsigned long size)
273 {
274 regs->pc += size;
275
276 /*
277 * If we were single stepping, we want to get the step exception after
278 * we return from the trap.
279 */
280 if (user_mode(regs))
281 user_fastforward_single_step(current);
282 }
283
284 static LIST_HEAD(undef_hook);
285 static DEFINE_RAW_SPINLOCK(undef_lock);
286
287 void register_undef_hook(struct undef_hook *hook)
288 {
289 unsigned long flags;
290
291 raw_spin_lock_irqsave(&undef_lock, flags);
292 list_add(&hook->node, &undef_hook);
293 raw_spin_unlock_irqrestore(&undef_lock, flags);
294 }
295
296 void unregister_undef_hook(struct undef_hook *hook)
297 {
298 unsigned long flags;
299
300 raw_spin_lock_irqsave(&undef_lock, flags);
301 list_del(&hook->node);
302 raw_spin_unlock_irqrestore(&undef_lock, flags);
303 }
304
305 static int call_undef_hook(struct pt_regs *regs)
306 {
307 struct undef_hook *hook;
308 unsigned long flags;
309 u32 instr;
310 int (*fn)(struct pt_regs *regs, u32 instr) = NULL;
311 void __user *pc = (void __user *)instruction_pointer(regs);
312
313 if (!user_mode(regs)) {
314 __le32 instr_le;
315 if (probe_kernel_address((__force __le32 *)pc, instr_le))
316 goto exit;
317 instr = le32_to_cpu(instr_le);
318 } else if (compat_thumb_mode(regs)) {
319 /* 16-bit Thumb instruction */
320 __le16 instr_le;
321 if (get_user(instr_le, (__le16 __user *)pc))
322 goto exit;
323 instr = le16_to_cpu(instr_le);
324 if (aarch32_insn_is_wide(instr)) {
325 u32 instr2;
326
327 if (get_user(instr_le, (__le16 __user *)(pc + 2)))
328 goto exit;
329 instr2 = le16_to_cpu(instr_le);
330 instr = (instr << 16) | instr2;
331 }
332 } else {
333 /* 32-bit ARM instruction */
334 __le32 instr_le;
335 if (get_user(instr_le, (__le32 __user *)pc))
336 goto exit;
337 instr = le32_to_cpu(instr_le);
338 }
339
340 raw_spin_lock_irqsave(&undef_lock, flags);
341 list_for_each_entry(hook, &undef_hook, node)
342 if ((instr & hook->instr_mask) == hook->instr_val &&
343 (regs->pstate & hook->pstate_mask) == hook->pstate_val)
344 fn = hook->fn;
345
346 raw_spin_unlock_irqrestore(&undef_lock, flags);
347 exit:
348 return fn ? fn(regs, instr) : 1;
349 }
350
351 void force_signal_inject(int signal, int code, unsigned long address)
352 {
353 siginfo_t info;
354 const char *desc;
355 struct pt_regs *regs = current_pt_regs();
356
357 if (WARN_ON(!user_mode(regs)))
358 return;
359
360 clear_siginfo(&info);
361
362 switch (signal) {
363 case SIGILL:
364 desc = "undefined instruction";
365 break;
366 case SIGSEGV:
367 desc = "illegal memory access";
368 break;
369 default:
370 desc = "unknown or unrecoverable error";
371 break;
372 }
373
374 /* Force signals we don't understand to SIGKILL */
375 if (WARN_ON(signal != SIGKILL &&
376 siginfo_layout(signal, code) != SIL_FAULT)) {
377 signal = SIGKILL;
378 }
379
380 info.si_signo = signal;
381 info.si_errno = 0;
382 info.si_code = code;
383 info.si_addr = (void __user *)address;
384
385 arm64_notify_die(desc, regs, &info, 0);
386 }
387
388 /*
389 * Set up process info to signal segmentation fault - called on access error.
390 */
391 void arm64_notify_segfault(unsigned long addr)
392 {
393 int code;
394
395 down_read(&current->mm->mmap_sem);
396 if (find_vma(current->mm, addr) == NULL)
397 code = SEGV_MAPERR;
398 else
399 code = SEGV_ACCERR;
400 up_read(&current->mm->mmap_sem);
401
402 force_signal_inject(SIGSEGV, code, addr);
403 }
404
405 asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
406 {
407 /* check for AArch32 breakpoint instructions */
408 if (!aarch32_break_handler(regs))
409 return;
410
411 if (call_undef_hook(regs) == 0)
412 return;
413
414 BUG_ON(!user_mode(regs));
415 force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc);
416 }
417
418 #define __user_cache_maint(insn, address, res) \
419 if (address >= user_addr_max()) { \
420 res = -EFAULT; \
421 } else { \
422 uaccess_ttbr0_enable(); \
423 asm volatile ( \
424 "1: " insn ", %1\n" \
425 " mov %w0, #0\n" \
426 "2:\n" \
427 " .pushsection .fixup,\"ax\"\n" \
428 " .align 2\n" \
429 "3: mov %w0, %w2\n" \
430 " b 2b\n" \
431 " .popsection\n" \
432 _ASM_EXTABLE(1b, 3b) \
433 : "=r" (res) \
434 : "r" (address), "i" (-EFAULT)); \
435 uaccess_ttbr0_disable(); \
436 }
437
438 static void user_cache_maint_handler(unsigned int esr, struct pt_regs *regs)
439 {
440 unsigned long address;
441 int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
442 int crm = (esr & ESR_ELx_SYS64_ISS_CRM_MASK) >> ESR_ELx_SYS64_ISS_CRM_SHIFT;
443 int ret = 0;
444
445 address = untagged_addr(pt_regs_read_reg(regs, rt));
446
447 switch (crm) {
448 case ESR_ELx_SYS64_ISS_CRM_DC_CVAU: /* DC CVAU, gets promoted */
449 __user_cache_maint("dc civac", address, ret);
450 break;
451 case ESR_ELx_SYS64_ISS_CRM_DC_CVAC: /* DC CVAC, gets promoted */
452 __user_cache_maint("dc civac", address, ret);
453 break;
454 case ESR_ELx_SYS64_ISS_CRM_DC_CVAP: /* DC CVAP */
455 __user_cache_maint("sys 3, c7, c12, 1", address, ret);
456 break;
457 case ESR_ELx_SYS64_ISS_CRM_DC_CIVAC: /* DC CIVAC */
458 __user_cache_maint("dc civac", address, ret);
459 break;
460 case ESR_ELx_SYS64_ISS_CRM_IC_IVAU: /* IC IVAU */
461 __user_cache_maint("ic ivau", address, ret);
462 break;
463 default:
464 force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc);
465 return;
466 }
467
468 if (ret)
469 arm64_notify_segfault(address);
470 else
471 arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
472 }
473
474 static void ctr_read_handler(unsigned int esr, struct pt_regs *regs)
475 {
476 int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
477 unsigned long val = arm64_ftr_reg_user_value(&arm64_ftr_reg_ctrel0);
478
479 pt_regs_write_reg(regs, rt, val);
480
481 arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
482 }
483
484 static void cntvct_read_handler(unsigned int esr, struct pt_regs *regs)
485 {
486 int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
487
488 pt_regs_write_reg(regs, rt, arch_counter_get_cntvct());
489 arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
490 }
491
492 static void cntfrq_read_handler(unsigned int esr, struct pt_regs *regs)
493 {
494 int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
495
496 pt_regs_write_reg(regs, rt, arch_timer_get_rate());
497 arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
498 }
499
500 struct sys64_hook {
501 unsigned int esr_mask;
502 unsigned int esr_val;
503 void (*handler)(unsigned int esr, struct pt_regs *regs);
504 };
505
506 static struct sys64_hook sys64_hooks[] = {
507 {
508 .esr_mask = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_MASK,
509 .esr_val = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_VAL,
510 .handler = user_cache_maint_handler,
511 },
512 {
513 /* Trap read access to CTR_EL0 */
514 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
515 .esr_val = ESR_ELx_SYS64_ISS_SYS_CTR_READ,
516 .handler = ctr_read_handler,
517 },
518 {
519 /* Trap read access to CNTVCT_EL0 */
520 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
521 .esr_val = ESR_ELx_SYS64_ISS_SYS_CNTVCT,
522 .handler = cntvct_read_handler,
523 },
524 {
525 /* Trap read access to CNTFRQ_EL0 */
526 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
527 .esr_val = ESR_ELx_SYS64_ISS_SYS_CNTFRQ,
528 .handler = cntfrq_read_handler,
529 },
530 {},
531 };
532
533 asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
534 {
535 struct sys64_hook *hook;
536
537 for (hook = sys64_hooks; hook->handler; hook++)
538 if ((hook->esr_mask & esr) == hook->esr_val) {
539 hook->handler(esr, regs);
540 return;
541 }
542
543 /*
544 * New SYS instructions may previously have been undefined at EL0. Fall
545 * back to our usual undefined instruction handler so that we handle
546 * these consistently.
547 */
548 do_undefinstr(regs);
549 }
550
551 static const char *esr_class_str[] = {
552 [0 ... ESR_ELx_EC_MAX] = "UNRECOGNIZED EC",
553 [ESR_ELx_EC_UNKNOWN] = "Unknown/Uncategorized",
554 [ESR_ELx_EC_WFx] = "WFI/WFE",
555 [ESR_ELx_EC_CP15_32] = "CP15 MCR/MRC",
556 [ESR_ELx_EC_CP15_64] = "CP15 MCRR/MRRC",
557 [ESR_ELx_EC_CP14_MR] = "CP14 MCR/MRC",
558 [ESR_ELx_EC_CP14_LS] = "CP14 LDC/STC",
559 [ESR_ELx_EC_FP_ASIMD] = "ASIMD",
560 [ESR_ELx_EC_CP10_ID] = "CP10 MRC/VMRS",
561 [ESR_ELx_EC_CP14_64] = "CP14 MCRR/MRRC",
562 [ESR_ELx_EC_ILL] = "PSTATE.IL",
563 [ESR_ELx_EC_SVC32] = "SVC (AArch32)",
564 [ESR_ELx_EC_HVC32] = "HVC (AArch32)",
565 [ESR_ELx_EC_SMC32] = "SMC (AArch32)",
566 [ESR_ELx_EC_SVC64] = "SVC (AArch64)",
567 [ESR_ELx_EC_HVC64] = "HVC (AArch64)",
568 [ESR_ELx_EC_SMC64] = "SMC (AArch64)",
569 [ESR_ELx_EC_SYS64] = "MSR/MRS (AArch64)",
570 [ESR_ELx_EC_SVE] = "SVE",
571 [ESR_ELx_EC_IMP_DEF] = "EL3 IMP DEF",
572 [ESR_ELx_EC_IABT_LOW] = "IABT (lower EL)",
573 [ESR_ELx_EC_IABT_CUR] = "IABT (current EL)",
574 [ESR_ELx_EC_PC_ALIGN] = "PC Alignment",
575 [ESR_ELx_EC_DABT_LOW] = "DABT (lower EL)",
576 [ESR_ELx_EC_DABT_CUR] = "DABT (current EL)",
577 [ESR_ELx_EC_SP_ALIGN] = "SP Alignment",
578 [ESR_ELx_EC_FP_EXC32] = "FP (AArch32)",
579 [ESR_ELx_EC_FP_EXC64] = "FP (AArch64)",
580 [ESR_ELx_EC_SERROR] = "SError",
581 [ESR_ELx_EC_BREAKPT_LOW] = "Breakpoint (lower EL)",
582 [ESR_ELx_EC_BREAKPT_CUR] = "Breakpoint (current EL)",
583 [ESR_ELx_EC_SOFTSTP_LOW] = "Software Step (lower EL)",
584 [ESR_ELx_EC_SOFTSTP_CUR] = "Software Step (current EL)",
585 [ESR_ELx_EC_WATCHPT_LOW] = "Watchpoint (lower EL)",
586 [ESR_ELx_EC_WATCHPT_CUR] = "Watchpoint (current EL)",
587 [ESR_ELx_EC_BKPT32] = "BKPT (AArch32)",
588 [ESR_ELx_EC_VECTOR32] = "Vector catch (AArch32)",
589 [ESR_ELx_EC_BRK64] = "BRK (AArch64)",
590 };
591
592 const char *esr_get_class_string(u32 esr)
593 {
594 return esr_class_str[ESR_ELx_EC(esr)];
595 }
596
597 /*
598 * bad_mode handles the impossible case in the exception vector. This is always
599 * fatal.
600 */
601 asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
602 {
603 console_verbose();
604
605 pr_crit("Bad mode in %s handler detected on CPU%d, code 0x%08x -- %s\n",
606 handler[reason], smp_processor_id(), esr,
607 esr_get_class_string(esr));
608
609 local_daif_mask();
610 panic("bad mode");
611 }
612
613 /*
614 * bad_el0_sync handles unexpected, but potentially recoverable synchronous
615 * exceptions taken from EL0. Unlike bad_mode, this returns.
616 */
617 asmlinkage void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr)
618 {
619 siginfo_t info;
620 void __user *pc = (void __user *)instruction_pointer(regs);
621
622 clear_siginfo(&info);
623 info.si_signo = SIGILL;
624 info.si_errno = 0;
625 info.si_code = ILL_ILLOPC;
626 info.si_addr = pc;
627
628 current->thread.fault_address = 0;
629 current->thread.fault_code = esr;
630
631 arm64_force_sig_info(&info, "Bad EL0 synchronous exception", current);
632 }
633
634 #ifdef CONFIG_VMAP_STACK
635
636 DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack)
637 __aligned(16);
638
639 asmlinkage void handle_bad_stack(struct pt_regs *regs)
640 {
641 unsigned long tsk_stk = (unsigned long)current->stack;
642 unsigned long irq_stk = (unsigned long)this_cpu_read(irq_stack_ptr);
643 unsigned long ovf_stk = (unsigned long)this_cpu_ptr(overflow_stack);
644 unsigned int esr = read_sysreg(esr_el1);
645 unsigned long far = read_sysreg(far_el1);
646
647 console_verbose();
648 pr_emerg("Insufficient stack space to handle exception!");
649
650 pr_emerg("ESR: 0x%08x -- %s\n", esr, esr_get_class_string(esr));
651 pr_emerg("FAR: 0x%016lx\n", far);
652
653 pr_emerg("Task stack: [0x%016lx..0x%016lx]\n",
654 tsk_stk, tsk_stk + THREAD_SIZE);
655 pr_emerg("IRQ stack: [0x%016lx..0x%016lx]\n",
656 irq_stk, irq_stk + THREAD_SIZE);
657 pr_emerg("Overflow stack: [0x%016lx..0x%016lx]\n",
658 ovf_stk, ovf_stk + OVERFLOW_STACK_SIZE);
659
660 __show_regs(regs);
661
662 /*
663 * We use nmi_panic to limit the potential for recusive overflows, and
664 * to get a better stack trace.
665 */
666 nmi_panic(NULL, "kernel stack overflow");
667 cpu_park_loop();
668 }
669 #endif
670
671 void __noreturn arm64_serror_panic(struct pt_regs *regs, u32 esr)
672 {
673 console_verbose();
674
675 pr_crit("SError Interrupt on CPU%d, code 0x%08x -- %s\n",
676 smp_processor_id(), esr, esr_get_class_string(esr));
677 if (regs)
678 __show_regs(regs);
679
680 nmi_panic(regs, "Asynchronous SError Interrupt");
681
682 cpu_park_loop();
683 unreachable();
684 }
685
686 bool arm64_is_fatal_ras_serror(struct pt_regs *regs, unsigned int esr)
687 {
688 u32 aet = arm64_ras_serror_get_severity(esr);
689
690 switch (aet) {
691 case ESR_ELx_AET_CE: /* corrected error */
692 case ESR_ELx_AET_UEO: /* restartable, not yet consumed */
693 /*
694 * The CPU can make progress. We may take UEO again as
695 * a more severe error.
696 */
697 return false;
698
699 case ESR_ELx_AET_UEU: /* Uncorrected Unrecoverable */
700 case ESR_ELx_AET_UER: /* Uncorrected Recoverable */
701 /*
702 * The CPU can't make progress. The exception may have
703 * been imprecise.
704 */
705 return true;
706
707 case ESR_ELx_AET_UC: /* Uncontainable or Uncategorized error */
708 default:
709 /* Error has been silently propagated */
710 arm64_serror_panic(regs, esr);
711 }
712 }
713
714 asmlinkage void do_serror(struct pt_regs *regs, unsigned int esr)
715 {
716 nmi_enter();
717
718 /* non-RAS errors are not containable */
719 if (!arm64_is_ras_serror(esr) || arm64_is_fatal_ras_serror(regs, esr))
720 arm64_serror_panic(regs, esr);
721
722 nmi_exit();
723 }
724
725 void __pte_error(const char *file, int line, unsigned long val)
726 {
727 pr_err("%s:%d: bad pte %016lx.\n", file, line, val);
728 }
729
730 void __pmd_error(const char *file, int line, unsigned long val)
731 {
732 pr_err("%s:%d: bad pmd %016lx.\n", file, line, val);
733 }
734
735 void __pud_error(const char *file, int line, unsigned long val)
736 {
737 pr_err("%s:%d: bad pud %016lx.\n", file, line, val);
738 }
739
740 void __pgd_error(const char *file, int line, unsigned long val)
741 {
742 pr_err("%s:%d: bad pgd %016lx.\n", file, line, val);
743 }
744
745 /* GENERIC_BUG traps */
746
747 int is_valid_bugaddr(unsigned long addr)
748 {
749 /*
750 * bug_handler() only called for BRK #BUG_BRK_IMM.
751 * So the answer is trivial -- any spurious instances with no
752 * bug table entry will be rejected by report_bug() and passed
753 * back to the debug-monitors code and handled as a fatal
754 * unexpected debug exception.
755 */
756 return 1;
757 }
758
759 static int bug_handler(struct pt_regs *regs, unsigned int esr)
760 {
761 if (user_mode(regs))
762 return DBG_HOOK_ERROR;
763
764 switch (report_bug(regs->pc, regs)) {
765 case BUG_TRAP_TYPE_BUG:
766 die("Oops - BUG", regs, 0);
767 break;
768
769 case BUG_TRAP_TYPE_WARN:
770 break;
771
772 default:
773 /* unknown/unrecognised bug trap type */
774 return DBG_HOOK_ERROR;
775 }
776
777 /* If thread survives, skip over the BUG instruction and continue: */
778 arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
779 return DBG_HOOK_HANDLED;
780 }
781
782 static struct break_hook bug_break_hook = {
783 .esr_val = 0xf2000000 | BUG_BRK_IMM,
784 .esr_mask = 0xffffffff,
785 .fn = bug_handler,
786 };
787
788 /*
789 * Initial handler for AArch64 BRK exceptions
790 * This handler only used until debug_traps_init().
791 */
792 int __init early_brk64(unsigned long addr, unsigned int esr,
793 struct pt_regs *regs)
794 {
795 return bug_handler(regs, esr) != DBG_HOOK_HANDLED;
796 }
797
798 /* This registration must happen early, before debug_traps_init(). */
799 void __init trap_init(void)
800 {
801 register_break_hook(&bug_break_hook);
802 }
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