1 // SPDX-License-Identifier: GPL-2.0-only
3 * Based on arch/arm/kernel/traps.c
5 * Copyright (C) 1995-2009 Russell King
6 * Copyright (C) 2012 ARM Ltd.
10 #include <linux/context_tracking.h>
11 #include <linux/signal.h>
12 #include <linux/personality.h>
13 #include <linux/kallsyms.h>
14 #include <linux/kprobes.h>
15 #include <linux/spinlock.h>
16 #include <linux/uaccess.h>
17 #include <linux/hardirq.h>
18 #include <linux/kdebug.h>
19 #include <linux/module.h>
20 #include <linux/kexec.h>
21 #include <linux/delay.h>
22 #include <linux/init.h>
23 #include <linux/sched/signal.h>
24 #include <linux/sched/debug.h>
25 #include <linux/sched/task_stack.h>
26 #include <linux/sizes.h>
27 #include <linux/syscalls.h>
28 #include <linux/mm_types.h>
29 #include <linux/kasan.h>
31 #include <asm/atomic.h>
33 #include <asm/cpufeature.h>
34 #include <asm/daifflags.h>
35 #include <asm/debug-monitors.h>
37 #include <asm/exception.h>
38 #include <asm/extable.h>
40 #include <asm/kprobes.h>
41 #include <asm/patching.h>
42 #include <asm/traps.h>
44 #include <asm/stack_pointer.h>
45 #include <asm/stacktrace.h>
46 #include <asm/system_misc.h>
47 #include <asm/sysreg.h>
49 static bool __kprobes __check_eq(unsigned long pstate)
51 return (pstate & PSR_Z_BIT) != 0;
54 static bool __kprobes __check_ne(unsigned long pstate)
56 return (pstate & PSR_Z_BIT) == 0;
59 static bool __kprobes __check_cs(unsigned long pstate)
61 return (pstate & PSR_C_BIT) != 0;
64 static bool __kprobes __check_cc(unsigned long pstate)
66 return (pstate & PSR_C_BIT) == 0;
69 static bool __kprobes __check_mi(unsigned long pstate)
71 return (pstate & PSR_N_BIT) != 0;
74 static bool __kprobes __check_pl(unsigned long pstate)
76 return (pstate & PSR_N_BIT) == 0;
79 static bool __kprobes __check_vs(unsigned long pstate)
81 return (pstate & PSR_V_BIT) != 0;
84 static bool __kprobes __check_vc(unsigned long pstate)
86 return (pstate & PSR_V_BIT) == 0;
89 static bool __kprobes __check_hi(unsigned long pstate)
91 pstate &= ~(pstate >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */
92 return (pstate & PSR_C_BIT) != 0;
95 static bool __kprobes __check_ls(unsigned long pstate)
97 pstate &= ~(pstate >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */
98 return (pstate & PSR_C_BIT) == 0;
101 static bool __kprobes __check_ge(unsigned long pstate)
103 pstate ^= (pstate << 3); /* PSR_N_BIT ^= PSR_V_BIT */
104 return (pstate & PSR_N_BIT) == 0;
107 static bool __kprobes __check_lt(unsigned long pstate)
109 pstate ^= (pstate << 3); /* PSR_N_BIT ^= PSR_V_BIT */
110 return (pstate & PSR_N_BIT) != 0;
113 static bool __kprobes __check_gt(unsigned long pstate)
115 /*PSR_N_BIT ^= PSR_V_BIT */
116 unsigned long temp = pstate ^ (pstate << 3);
118 temp |= (pstate << 1); /*PSR_N_BIT |= PSR_Z_BIT */
119 return (temp & PSR_N_BIT) == 0;
122 static bool __kprobes __check_le(unsigned long pstate)
124 /*PSR_N_BIT ^= PSR_V_BIT */
125 unsigned long temp = pstate ^ (pstate << 3);
127 temp |= (pstate << 1); /*PSR_N_BIT |= PSR_Z_BIT */
128 return (temp & PSR_N_BIT) != 0;
131 static bool __kprobes __check_al(unsigned long pstate)
137 * Note that the ARMv8 ARM calls condition code 0b1111 "nv", but states that
138 * it behaves identically to 0b1110 ("al").
140 pstate_check_t * const aarch32_opcode_cond_checks[16] = {
141 __check_eq, __check_ne, __check_cs, __check_cc,
142 __check_mi, __check_pl, __check_vs, __check_vc,
143 __check_hi, __check_ls, __check_ge, __check_lt,
144 __check_gt, __check_le, __check_al, __check_al
147 int show_unhandled_signals = 0;
149 static void dump_kernel_instr(const char *lvl, struct pt_regs *regs)
151 unsigned long addr = instruction_pointer(regs);
152 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
158 for (i = -4; i < 1; i++) {
159 unsigned int val, bad;
161 bad = aarch64_insn_read(&((u32 *)addr)[i], &val);
164 p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
166 p += sprintf(p, "bad PC value");
171 printk("%sCode: %s\n", lvl, str);
174 #ifdef CONFIG_PREEMPT
175 #define S_PREEMPT " PREEMPT"
176 #elif defined(CONFIG_PREEMPT_RT)
177 #define S_PREEMPT " PREEMPT_RT"
184 static int __die(const char *str, int err, struct pt_regs *regs)
186 static int die_counter;
189 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
190 str, err, ++die_counter);
192 /* trap and error numbers are mostly meaningless on ARM */
193 ret = notify_die(DIE_OOPS, str, regs, err, 0, SIGSEGV);
194 if (ret == NOTIFY_STOP)
200 dump_kernel_instr(KERN_EMERG, regs);
205 static DEFINE_RAW_SPINLOCK(die_lock);
208 * This function is protected against re-entrancy.
210 void die(const char *str, struct pt_regs *regs, int err)
215 raw_spin_lock_irqsave(&die_lock, flags);
221 ret = __die(str, err, regs);
223 if (regs && kexec_should_crash(current))
227 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
231 panic("%s: Fatal exception in interrupt", str);
233 panic("%s: Fatal exception", str);
235 raw_spin_unlock_irqrestore(&die_lock, flags);
237 if (ret != NOTIFY_STOP)
241 static void arm64_show_signal(int signo, const char *str)
243 static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL,
244 DEFAULT_RATELIMIT_BURST);
245 struct task_struct *tsk = current;
246 unsigned int esr = tsk->thread.fault_code;
247 struct pt_regs *regs = task_pt_regs(tsk);
249 /* Leave if the signal won't be shown */
250 if (!show_unhandled_signals ||
251 !unhandled_signal(tsk, signo) ||
255 pr_info("%s[%d]: unhandled exception: ", tsk->comm, task_pid_nr(tsk));
257 pr_cont("%s, ESR 0x%08x, ", esr_get_class_string(esr), esr);
260 print_vma_addr(KERN_CONT " in ", regs->pc);
265 void arm64_force_sig_fault(int signo, int code, unsigned long far,
268 arm64_show_signal(signo, str);
269 if (signo == SIGKILL)
272 force_sig_fault(signo, code, (void __user *)far);
275 void arm64_force_sig_mceerr(int code, unsigned long far, short lsb,
278 arm64_show_signal(SIGBUS, str);
279 force_sig_mceerr(code, (void __user *)far, lsb);
282 void arm64_force_sig_ptrace_errno_trap(int errno, unsigned long far,
285 arm64_show_signal(SIGTRAP, str);
286 force_sig_ptrace_errno_trap(errno, (void __user *)far);
289 void arm64_notify_die(const char *str, struct pt_regs *regs,
290 int signo, int sicode, unsigned long far,
293 if (user_mode(regs)) {
294 WARN_ON(regs != current_pt_regs());
295 current->thread.fault_address = 0;
296 current->thread.fault_code = err;
298 arm64_force_sig_fault(signo, sicode, far, str);
305 #define PSTATE_IT_1_0_SHIFT 25
306 #define PSTATE_IT_1_0_MASK (0x3 << PSTATE_IT_1_0_SHIFT)
307 #define PSTATE_IT_7_2_SHIFT 10
308 #define PSTATE_IT_7_2_MASK (0x3f << PSTATE_IT_7_2_SHIFT)
310 static u32 compat_get_it_state(struct pt_regs *regs)
312 u32 it, pstate = regs->pstate;
314 it = (pstate & PSTATE_IT_1_0_MASK) >> PSTATE_IT_1_0_SHIFT;
315 it |= ((pstate & PSTATE_IT_7_2_MASK) >> PSTATE_IT_7_2_SHIFT) << 2;
320 static void compat_set_it_state(struct pt_regs *regs, u32 it)
324 pstate_it = (it << PSTATE_IT_1_0_SHIFT) & PSTATE_IT_1_0_MASK;
325 pstate_it |= ((it >> 2) << PSTATE_IT_7_2_SHIFT) & PSTATE_IT_7_2_MASK;
327 regs->pstate &= ~PSR_AA32_IT_MASK;
328 regs->pstate |= pstate_it;
331 static void advance_itstate(struct pt_regs *regs)
336 if (!(regs->pstate & PSR_AA32_T_BIT) ||
337 !(regs->pstate & PSR_AA32_IT_MASK))
340 it = compat_get_it_state(regs);
343 * If this is the last instruction of the block, wipe the IT
344 * state. Otherwise advance it.
349 it = (it & 0xe0) | ((it << 1) & 0x1f);
351 compat_set_it_state(regs, it);
354 static void advance_itstate(struct pt_regs *regs)
359 void arm64_skip_faulting_instruction(struct pt_regs *regs, unsigned long size)
364 * If we were single stepping, we want to get the step exception after
365 * we return from the trap.
368 user_fastforward_single_step(current);
370 if (compat_user_mode(regs))
371 advance_itstate(regs);
373 regs->pstate &= ~PSR_BTYPE_MASK;
376 static LIST_HEAD(undef_hook);
377 static DEFINE_RAW_SPINLOCK(undef_lock);
379 void register_undef_hook(struct undef_hook *hook)
383 raw_spin_lock_irqsave(&undef_lock, flags);
384 list_add(&hook->node, &undef_hook);
385 raw_spin_unlock_irqrestore(&undef_lock, flags);
388 void unregister_undef_hook(struct undef_hook *hook)
392 raw_spin_lock_irqsave(&undef_lock, flags);
393 list_del(&hook->node);
394 raw_spin_unlock_irqrestore(&undef_lock, flags);
397 static int call_undef_hook(struct pt_regs *regs)
399 struct undef_hook *hook;
402 int (*fn)(struct pt_regs *regs, u32 instr) = NULL;
403 void __user *pc = (void __user *)instruction_pointer(regs);
405 if (!user_mode(regs)) {
407 if (get_kernel_nofault(instr_le, (__force __le32 *)pc))
409 instr = le32_to_cpu(instr_le);
410 } else if (compat_thumb_mode(regs)) {
411 /* 16-bit Thumb instruction */
413 if (get_user(instr_le, (__le16 __user *)pc))
415 instr = le16_to_cpu(instr_le);
416 if (aarch32_insn_is_wide(instr)) {
419 if (get_user(instr_le, (__le16 __user *)(pc + 2)))
421 instr2 = le16_to_cpu(instr_le);
422 instr = (instr << 16) | instr2;
425 /* 32-bit ARM instruction */
427 if (get_user(instr_le, (__le32 __user *)pc))
429 instr = le32_to_cpu(instr_le);
432 raw_spin_lock_irqsave(&undef_lock, flags);
433 list_for_each_entry(hook, &undef_hook, node)
434 if ((instr & hook->instr_mask) == hook->instr_val &&
435 (regs->pstate & hook->pstate_mask) == hook->pstate_val)
438 raw_spin_unlock_irqrestore(&undef_lock, flags);
440 return fn ? fn(regs, instr) : 1;
443 void force_signal_inject(int signal, int code, unsigned long address, unsigned int err)
446 struct pt_regs *regs = current_pt_regs();
448 if (WARN_ON(!user_mode(regs)))
453 desc = "undefined instruction";
456 desc = "illegal memory access";
459 desc = "unknown or unrecoverable error";
463 /* Force signals we don't understand to SIGKILL */
464 if (WARN_ON(signal != SIGKILL &&
465 siginfo_layout(signal, code) != SIL_FAULT)) {
469 arm64_notify_die(desc, regs, signal, code, address, err);
473 * Set up process info to signal segmentation fault - called on access error.
475 void arm64_notify_segfault(unsigned long addr)
479 mmap_read_lock(current->mm);
480 if (find_vma(current->mm, untagged_addr(addr)) == NULL)
484 mmap_read_unlock(current->mm);
486 force_signal_inject(SIGSEGV, code, addr, 0);
489 void do_undefinstr(struct pt_regs *regs)
491 /* check for AArch32 breakpoint instructions */
492 if (!aarch32_break_handler(regs))
495 if (call_undef_hook(regs) == 0)
498 BUG_ON(!user_mode(regs));
499 force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0);
501 NOKPROBE_SYMBOL(do_undefinstr);
503 void do_bti(struct pt_regs *regs)
505 BUG_ON(!user_mode(regs));
506 force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0);
508 NOKPROBE_SYMBOL(do_bti);
510 void do_ptrauth_fault(struct pt_regs *regs, unsigned int esr)
513 * Unexpected FPAC exception or pointer authentication failure in
514 * the kernel: kill the task before it does any more harm.
516 BUG_ON(!user_mode(regs));
517 force_signal_inject(SIGILL, ILL_ILLOPN, regs->pc, esr);
519 NOKPROBE_SYMBOL(do_ptrauth_fault);
521 #define __user_cache_maint(insn, address, res) \
522 if (address >= user_addr_max()) { \
525 uaccess_ttbr0_enable(); \
527 "1: " insn ", %1\n" \
530 " .pushsection .fixup,\"ax\"\n" \
532 "3: mov %w0, %w2\n" \
535 _ASM_EXTABLE(1b, 3b) \
537 : "r" (address), "i" (-EFAULT)); \
538 uaccess_ttbr0_disable(); \
541 static void user_cache_maint_handler(unsigned int esr, struct pt_regs *regs)
543 unsigned long tagged_address, address;
544 int rt = ESR_ELx_SYS64_ISS_RT(esr);
545 int crm = (esr & ESR_ELx_SYS64_ISS_CRM_MASK) >> ESR_ELx_SYS64_ISS_CRM_SHIFT;
548 tagged_address = pt_regs_read_reg(regs, rt);
549 address = untagged_addr(tagged_address);
552 case ESR_ELx_SYS64_ISS_CRM_DC_CVAU: /* DC CVAU, gets promoted */
553 __user_cache_maint("dc civac", address, ret);
555 case ESR_ELx_SYS64_ISS_CRM_DC_CVAC: /* DC CVAC, gets promoted */
556 __user_cache_maint("dc civac", address, ret);
558 case ESR_ELx_SYS64_ISS_CRM_DC_CVADP: /* DC CVADP */
559 __user_cache_maint("sys 3, c7, c13, 1", address, ret);
561 case ESR_ELx_SYS64_ISS_CRM_DC_CVAP: /* DC CVAP */
562 __user_cache_maint("sys 3, c7, c12, 1", address, ret);
564 case ESR_ELx_SYS64_ISS_CRM_DC_CIVAC: /* DC CIVAC */
565 __user_cache_maint("dc civac", address, ret);
567 case ESR_ELx_SYS64_ISS_CRM_IC_IVAU: /* IC IVAU */
568 __user_cache_maint("ic ivau", address, ret);
571 force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0);
576 arm64_notify_segfault(tagged_address);
578 arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
581 static void ctr_read_handler(unsigned int esr, struct pt_regs *regs)
583 int rt = ESR_ELx_SYS64_ISS_RT(esr);
584 unsigned long val = arm64_ftr_reg_user_value(&arm64_ftr_reg_ctrel0);
586 if (cpus_have_const_cap(ARM64_WORKAROUND_1542419)) {
587 /* Hide DIC so that we can trap the unnecessary maintenance...*/
588 val &= ~BIT(CTR_DIC_SHIFT);
590 /* ... and fake IminLine to reduce the number of traps. */
591 val &= ~CTR_IMINLINE_MASK;
592 val |= (PAGE_SHIFT - 2) & CTR_IMINLINE_MASK;
595 pt_regs_write_reg(regs, rt, val);
597 arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
600 static void cntvct_read_handler(unsigned int esr, struct pt_regs *regs)
602 int rt = ESR_ELx_SYS64_ISS_RT(esr);
604 pt_regs_write_reg(regs, rt, arch_timer_read_counter());
605 arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
608 static void cntfrq_read_handler(unsigned int esr, struct pt_regs *regs)
610 int rt = ESR_ELx_SYS64_ISS_RT(esr);
612 pt_regs_write_reg(regs, rt, arch_timer_get_rate());
613 arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
616 static void mrs_handler(unsigned int esr, struct pt_regs *regs)
620 rt = ESR_ELx_SYS64_ISS_RT(esr);
621 sysreg = esr_sys64_to_sysreg(esr);
623 if (do_emulate_mrs(regs, sysreg, rt) != 0)
624 force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0);
627 static void wfi_handler(unsigned int esr, struct pt_regs *regs)
629 arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
633 unsigned int esr_mask;
634 unsigned int esr_val;
635 void (*handler)(unsigned int esr, struct pt_regs *regs);
638 static const struct sys64_hook sys64_hooks[] = {
640 .esr_mask = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_MASK,
641 .esr_val = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_VAL,
642 .handler = user_cache_maint_handler,
645 /* Trap read access to CTR_EL0 */
646 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
647 .esr_val = ESR_ELx_SYS64_ISS_SYS_CTR_READ,
648 .handler = ctr_read_handler,
651 /* Trap read access to CNTVCT_EL0 */
652 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
653 .esr_val = ESR_ELx_SYS64_ISS_SYS_CNTVCT,
654 .handler = cntvct_read_handler,
657 /* Trap read access to CNTFRQ_EL0 */
658 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
659 .esr_val = ESR_ELx_SYS64_ISS_SYS_CNTFRQ,
660 .handler = cntfrq_read_handler,
663 /* Trap read access to CPUID registers */
664 .esr_mask = ESR_ELx_SYS64_ISS_SYS_MRS_OP_MASK,
665 .esr_val = ESR_ELx_SYS64_ISS_SYS_MRS_OP_VAL,
666 .handler = mrs_handler,
669 /* Trap WFI instructions executed in userspace */
670 .esr_mask = ESR_ELx_WFx_MASK,
671 .esr_val = ESR_ELx_WFx_WFI_VAL,
672 .handler = wfi_handler,
678 static bool cp15_cond_valid(unsigned int esr, struct pt_regs *regs)
682 /* Only a T32 instruction can trap without CV being set */
683 if (!(esr & ESR_ELx_CV)) {
686 it = compat_get_it_state(regs);
692 cond = (esr & ESR_ELx_COND_MASK) >> ESR_ELx_COND_SHIFT;
695 return aarch32_opcode_cond_checks[cond](regs->pstate);
698 static void compat_cntfrq_read_handler(unsigned int esr, struct pt_regs *regs)
700 int reg = (esr & ESR_ELx_CP15_32_ISS_RT_MASK) >> ESR_ELx_CP15_32_ISS_RT_SHIFT;
702 pt_regs_write_reg(regs, reg, arch_timer_get_rate());
703 arm64_skip_faulting_instruction(regs, 4);
706 static const struct sys64_hook cp15_32_hooks[] = {
708 .esr_mask = ESR_ELx_CP15_32_ISS_SYS_MASK,
709 .esr_val = ESR_ELx_CP15_32_ISS_SYS_CNTFRQ,
710 .handler = compat_cntfrq_read_handler,
715 static void compat_cntvct_read_handler(unsigned int esr, struct pt_regs *regs)
717 int rt = (esr & ESR_ELx_CP15_64_ISS_RT_MASK) >> ESR_ELx_CP15_64_ISS_RT_SHIFT;
718 int rt2 = (esr & ESR_ELx_CP15_64_ISS_RT2_MASK) >> ESR_ELx_CP15_64_ISS_RT2_SHIFT;
719 u64 val = arch_timer_read_counter();
721 pt_regs_write_reg(regs, rt, lower_32_bits(val));
722 pt_regs_write_reg(regs, rt2, upper_32_bits(val));
723 arm64_skip_faulting_instruction(regs, 4);
726 static const struct sys64_hook cp15_64_hooks[] = {
728 .esr_mask = ESR_ELx_CP15_64_ISS_SYS_MASK,
729 .esr_val = ESR_ELx_CP15_64_ISS_SYS_CNTVCT,
730 .handler = compat_cntvct_read_handler,
735 void do_cp15instr(unsigned int esr, struct pt_regs *regs)
737 const struct sys64_hook *hook, *hook_base;
739 if (!cp15_cond_valid(esr, regs)) {
741 * There is no T16 variant of a CP access, so we
742 * always advance PC by 4 bytes.
744 arm64_skip_faulting_instruction(regs, 4);
748 switch (ESR_ELx_EC(esr)) {
749 case ESR_ELx_EC_CP15_32:
750 hook_base = cp15_32_hooks;
752 case ESR_ELx_EC_CP15_64:
753 hook_base = cp15_64_hooks;
760 for (hook = hook_base; hook->handler; hook++)
761 if ((hook->esr_mask & esr) == hook->esr_val) {
762 hook->handler(esr, regs);
767 * New cp15 instructions may previously have been undefined at
768 * EL0. Fall back to our usual undefined instruction handler
769 * so that we handle these consistently.
773 NOKPROBE_SYMBOL(do_cp15instr);
776 void do_sysinstr(unsigned int esr, struct pt_regs *regs)
778 const struct sys64_hook *hook;
780 for (hook = sys64_hooks; hook->handler; hook++)
781 if ((hook->esr_mask & esr) == hook->esr_val) {
782 hook->handler(esr, regs);
787 * New SYS instructions may previously have been undefined at EL0. Fall
788 * back to our usual undefined instruction handler so that we handle
789 * these consistently.
793 NOKPROBE_SYMBOL(do_sysinstr);
795 static const char *esr_class_str[] = {
796 [0 ... ESR_ELx_EC_MAX] = "UNRECOGNIZED EC",
797 [ESR_ELx_EC_UNKNOWN] = "Unknown/Uncategorized",
798 [ESR_ELx_EC_WFx] = "WFI/WFE",
799 [ESR_ELx_EC_CP15_32] = "CP15 MCR/MRC",
800 [ESR_ELx_EC_CP15_64] = "CP15 MCRR/MRRC",
801 [ESR_ELx_EC_CP14_MR] = "CP14 MCR/MRC",
802 [ESR_ELx_EC_CP14_LS] = "CP14 LDC/STC",
803 [ESR_ELx_EC_FP_ASIMD] = "ASIMD",
804 [ESR_ELx_EC_CP10_ID] = "CP10 MRC/VMRS",
805 [ESR_ELx_EC_PAC] = "PAC",
806 [ESR_ELx_EC_CP14_64] = "CP14 MCRR/MRRC",
807 [ESR_ELx_EC_BTI] = "BTI",
808 [ESR_ELx_EC_ILL] = "PSTATE.IL",
809 [ESR_ELx_EC_SVC32] = "SVC (AArch32)",
810 [ESR_ELx_EC_HVC32] = "HVC (AArch32)",
811 [ESR_ELx_EC_SMC32] = "SMC (AArch32)",
812 [ESR_ELx_EC_SVC64] = "SVC (AArch64)",
813 [ESR_ELx_EC_HVC64] = "HVC (AArch64)",
814 [ESR_ELx_EC_SMC64] = "SMC (AArch64)",
815 [ESR_ELx_EC_SYS64] = "MSR/MRS (AArch64)",
816 [ESR_ELx_EC_SVE] = "SVE",
817 [ESR_ELx_EC_ERET] = "ERET/ERETAA/ERETAB",
818 [ESR_ELx_EC_FPAC] = "FPAC",
819 [ESR_ELx_EC_IMP_DEF] = "EL3 IMP DEF",
820 [ESR_ELx_EC_IABT_LOW] = "IABT (lower EL)",
821 [ESR_ELx_EC_IABT_CUR] = "IABT (current EL)",
822 [ESR_ELx_EC_PC_ALIGN] = "PC Alignment",
823 [ESR_ELx_EC_DABT_LOW] = "DABT (lower EL)",
824 [ESR_ELx_EC_DABT_CUR] = "DABT (current EL)",
825 [ESR_ELx_EC_SP_ALIGN] = "SP Alignment",
826 [ESR_ELx_EC_FP_EXC32] = "FP (AArch32)",
827 [ESR_ELx_EC_FP_EXC64] = "FP (AArch64)",
828 [ESR_ELx_EC_SERROR] = "SError",
829 [ESR_ELx_EC_BREAKPT_LOW] = "Breakpoint (lower EL)",
830 [ESR_ELx_EC_BREAKPT_CUR] = "Breakpoint (current EL)",
831 [ESR_ELx_EC_SOFTSTP_LOW] = "Software Step (lower EL)",
832 [ESR_ELx_EC_SOFTSTP_CUR] = "Software Step (current EL)",
833 [ESR_ELx_EC_WATCHPT_LOW] = "Watchpoint (lower EL)",
834 [ESR_ELx_EC_WATCHPT_CUR] = "Watchpoint (current EL)",
835 [ESR_ELx_EC_BKPT32] = "BKPT (AArch32)",
836 [ESR_ELx_EC_VECTOR32] = "Vector catch (AArch32)",
837 [ESR_ELx_EC_BRK64] = "BRK (AArch64)",
840 const char *esr_get_class_string(u32 esr)
842 return esr_class_str[ESR_ELx_EC(esr)];
846 * bad_el0_sync handles unexpected, but potentially recoverable synchronous
847 * exceptions taken from EL0.
849 void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr)
851 unsigned long pc = instruction_pointer(regs);
853 current->thread.fault_address = 0;
854 current->thread.fault_code = esr;
856 arm64_force_sig_fault(SIGILL, ILL_ILLOPC, pc,
857 "Bad EL0 synchronous exception");
860 #ifdef CONFIG_VMAP_STACK
862 DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack)
865 void panic_bad_stack(struct pt_regs *regs, unsigned int esr, unsigned long far)
867 unsigned long tsk_stk = (unsigned long)current->stack;
868 unsigned long irq_stk = (unsigned long)this_cpu_read(irq_stack_ptr);
869 unsigned long ovf_stk = (unsigned long)this_cpu_ptr(overflow_stack);
872 pr_emerg("Insufficient stack space to handle exception!");
874 pr_emerg("ESR: 0x%08x -- %s\n", esr, esr_get_class_string(esr));
875 pr_emerg("FAR: 0x%016lx\n", far);
877 pr_emerg("Task stack: [0x%016lx..0x%016lx]\n",
878 tsk_stk, tsk_stk + THREAD_SIZE);
879 pr_emerg("IRQ stack: [0x%016lx..0x%016lx]\n",
880 irq_stk, irq_stk + IRQ_STACK_SIZE);
881 pr_emerg("Overflow stack: [0x%016lx..0x%016lx]\n",
882 ovf_stk, ovf_stk + OVERFLOW_STACK_SIZE);
887 * We use nmi_panic to limit the potential for recusive overflows, and
888 * to get a better stack trace.
890 nmi_panic(NULL, "kernel stack overflow");
895 void __noreturn arm64_serror_panic(struct pt_regs *regs, u32 esr)
899 pr_crit("SError Interrupt on CPU%d, code 0x%08x -- %s\n",
900 smp_processor_id(), esr, esr_get_class_string(esr));
904 nmi_panic(regs, "Asynchronous SError Interrupt");
910 bool arm64_is_fatal_ras_serror(struct pt_regs *regs, unsigned int esr)
912 u32 aet = arm64_ras_serror_get_severity(esr);
915 case ESR_ELx_AET_CE: /* corrected error */
916 case ESR_ELx_AET_UEO: /* restartable, not yet consumed */
918 * The CPU can make progress. We may take UEO again as
919 * a more severe error.
923 case ESR_ELx_AET_UEU: /* Uncorrected Unrecoverable */
924 case ESR_ELx_AET_UER: /* Uncorrected Recoverable */
926 * The CPU can't make progress. The exception may have
929 * Neoverse-N1 #1349291 means a non-KVM SError reported as
930 * Unrecoverable should be treated as Uncontainable. We
931 * call arm64_serror_panic() in both cases.
935 case ESR_ELx_AET_UC: /* Uncontainable or Uncategorized error */
937 /* Error has been silently propagated */
938 arm64_serror_panic(regs, esr);
942 void do_serror(struct pt_regs *regs, unsigned int esr)
944 /* non-RAS errors are not containable */
945 if (!arm64_is_ras_serror(esr) || arm64_is_fatal_ras_serror(regs, esr))
946 arm64_serror_panic(regs, esr);
949 /* GENERIC_BUG traps */
951 int is_valid_bugaddr(unsigned long addr)
954 * bug_handler() only called for BRK #BUG_BRK_IMM.
955 * So the answer is trivial -- any spurious instances with no
956 * bug table entry will be rejected by report_bug() and passed
957 * back to the debug-monitors code and handled as a fatal
958 * unexpected debug exception.
963 static int bug_handler(struct pt_regs *regs, unsigned int esr)
965 switch (report_bug(regs->pc, regs)) {
966 case BUG_TRAP_TYPE_BUG:
967 die("Oops - BUG", regs, 0);
970 case BUG_TRAP_TYPE_WARN:
974 /* unknown/unrecognised bug trap type */
975 return DBG_HOOK_ERROR;
978 /* If thread survives, skip over the BUG instruction and continue: */
979 arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
980 return DBG_HOOK_HANDLED;
983 static struct break_hook bug_break_hook = {
988 static int reserved_fault_handler(struct pt_regs *regs, unsigned int esr)
990 pr_err("%s generated an invalid instruction at %pS!\n",
991 "Kernel text patching",
992 (void *)instruction_pointer(regs));
994 /* We cannot handle this */
995 return DBG_HOOK_ERROR;
998 static struct break_hook fault_break_hook = {
999 .fn = reserved_fault_handler,
1000 .imm = FAULT_BRK_IMM,
1003 #ifdef CONFIG_KASAN_SW_TAGS
1005 #define KASAN_ESR_RECOVER 0x20
1006 #define KASAN_ESR_WRITE 0x10
1007 #define KASAN_ESR_SIZE_MASK 0x0f
1008 #define KASAN_ESR_SIZE(esr) (1 << ((esr) & KASAN_ESR_SIZE_MASK))
1010 static int kasan_handler(struct pt_regs *regs, unsigned int esr)
1012 bool recover = esr & KASAN_ESR_RECOVER;
1013 bool write = esr & KASAN_ESR_WRITE;
1014 size_t size = KASAN_ESR_SIZE(esr);
1015 u64 addr = regs->regs[0];
1018 kasan_report(addr, size, write, pc);
1021 * The instrumentation allows to control whether we can proceed after
1022 * a crash was detected. This is done by passing the -recover flag to
1023 * the compiler. Disabling recovery allows to generate more compact
1026 * Unfortunately disabling recovery doesn't work for the kernel right
1027 * now. KASAN reporting is disabled in some contexts (for example when
1028 * the allocator accesses slab object metadata; this is controlled by
1029 * current->kasan_depth). All these accesses are detected by the tool,
1030 * even though the reports for them are not printed.
1032 * This is something that might be fixed at some point in the future.
1035 die("Oops - KASAN", regs, 0);
1037 /* If thread survives, skip over the brk instruction and continue: */
1038 arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
1039 return DBG_HOOK_HANDLED;
1042 static struct break_hook kasan_break_hook = {
1043 .fn = kasan_handler,
1044 .imm = KASAN_BRK_IMM,
1045 .mask = KASAN_BRK_MASK,
1050 * Initial handler for AArch64 BRK exceptions
1051 * This handler only used until debug_traps_init().
1053 int __init early_brk64(unsigned long addr, unsigned int esr,
1054 struct pt_regs *regs)
1056 #ifdef CONFIG_KASAN_SW_TAGS
1057 unsigned int comment = esr & ESR_ELx_BRK64_ISS_COMMENT_MASK;
1059 if ((comment & ~KASAN_BRK_MASK) == KASAN_BRK_IMM)
1060 return kasan_handler(regs, esr) != DBG_HOOK_HANDLED;
1062 return bug_handler(regs, esr) != DBG_HOOK_HANDLED;
1065 void __init trap_init(void)
1067 register_kernel_break_hook(&bug_break_hook);
1068 register_kernel_break_hook(&fault_break_hook);
1069 #ifdef CONFIG_KASAN_SW_TAGS
1070 register_kernel_break_hook(&kasan_break_hook);