2 * Based on arch/arm/kernel/traps.c
4 * Copyright (C) 1995-2009 Russell King
5 * Copyright (C) 2012 ARM Ltd.
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.
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.
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/>.
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>
39 #include <asm/atomic.h>
41 #include <asm/cpufeature.h>
42 #include <asm/daifflags.h>
43 #include <asm/debug-monitors.h>
46 #include <asm/traps.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>
54 static const char *handler[]= {
61 int show_unhandled_signals = 0;
63 static void dump_backtrace_entry(unsigned long where)
65 printk(" %pS\n", (void *)where);
68 static void __dump_instr(const char *lvl, struct pt_regs *regs)
70 unsigned long addr = instruction_pointer(regs);
71 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
74 for (i = -4; i < 1; i++) {
75 unsigned int val, bad;
77 bad = get_user(val, &((u32 *)addr)[i]);
80 p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
82 p += sprintf(p, "bad PC value");
86 printk("%sCode: %s\n", lvl, str);
89 static void dump_instr(const char *lvl, struct pt_regs *regs)
91 if (!user_mode(regs)) {
92 mm_segment_t fs = get_fs();
94 __dump_instr(lvl, regs);
97 __dump_instr(lvl, regs);
101 void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
103 struct stackframe frame;
106 pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
111 if (!try_get_task_stack(tsk))
114 if (tsk == current) {
115 frame.fp = (unsigned long)__builtin_frame_address(0);
116 frame.pc = (unsigned long)dump_backtrace;
119 * task blocked in __switch_to
121 frame.fp = thread_saved_fp(tsk);
122 frame.pc = thread_saved_pc(tsk);
124 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
125 frame.graph = tsk->curr_ret_stack;
129 printk("Call trace:\n");
131 /* skip until specified stack frame */
133 dump_backtrace_entry(frame.pc);
134 } else if (frame.fp == regs->regs[29]) {
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
143 dump_backtrace_entry(regs->pc);
145 } while (!unwind_frame(tsk, &frame));
150 void show_stack(struct task_struct *tsk, unsigned long *sp)
152 dump_backtrace(NULL, tsk);
156 #ifdef CONFIG_PREEMPT
157 #define S_PREEMPT " PREEMPT"
163 static int __die(const char *str, int err, struct pt_regs *regs)
165 struct task_struct *tsk = current;
166 static int die_counter;
169 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
170 str, err, ++die_counter);
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)
179 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
180 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk),
183 if (!user_mode(regs)) {
184 dump_backtrace(regs, tsk);
185 dump_instr(KERN_EMERG, regs);
191 static DEFINE_RAW_SPINLOCK(die_lock);
194 * This function is protected against re-entrancy.
196 void die(const char *str, struct pt_regs *regs, int err)
201 raw_spin_lock_irqsave(&die_lock, flags);
207 ret = __die(str, err, regs);
209 if (regs && kexec_should_crash(current))
213 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
217 panic("Fatal exception in interrupt");
219 panic("Fatal exception");
221 raw_spin_unlock_irqrestore(&die_lock, flags);
223 if (ret != NOTIFY_STOP)
227 static void arm64_show_signal(int signo, const char *str)
229 static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL,
230 DEFAULT_RATELIMIT_BURST);
231 struct task_struct *tsk = current;
232 unsigned int esr = tsk->thread.fault_code;
233 struct pt_regs *regs = task_pt_regs(tsk);
235 /* Leave if the signal won't be shown */
236 if (!show_unhandled_signals ||
237 !unhandled_signal(tsk, signo) ||
241 pr_info("%s[%d]: unhandled exception: ", tsk->comm, task_pid_nr(tsk));
243 pr_cont("%s, ESR 0x%08x, ", esr_get_class_string(esr), esr);
246 print_vma_addr(KERN_CONT " in ", regs->pc);
251 void arm64_force_sig_fault(int signo, int code, void __user *addr,
254 arm64_show_signal(signo, str);
255 force_sig_fault(signo, code, addr, current);
258 void arm64_force_sig_mceerr(int code, void __user *addr, short lsb,
261 arm64_show_signal(SIGBUS, str);
262 force_sig_mceerr(code, addr, lsb, current);
265 void arm64_force_sig_ptrace_errno_trap(int errno, void __user *addr,
268 arm64_show_signal(SIGTRAP, str);
269 force_sig_ptrace_errno_trap(errno, addr);
272 void arm64_notify_die(const char *str, struct pt_regs *regs,
273 int signo, int sicode, void __user *addr,
276 if (user_mode(regs)) {
277 WARN_ON(regs != current_pt_regs());
278 current->thread.fault_address = 0;
279 current->thread.fault_code = err;
281 arm64_force_sig_fault(signo, sicode, addr, str);
287 void arm64_skip_faulting_instruction(struct pt_regs *regs, unsigned long size)
292 * If we were single stepping, we want to get the step exception after
293 * we return from the trap.
296 user_fastforward_single_step(current);
299 static LIST_HEAD(undef_hook);
300 static DEFINE_RAW_SPINLOCK(undef_lock);
302 void register_undef_hook(struct undef_hook *hook)
306 raw_spin_lock_irqsave(&undef_lock, flags);
307 list_add(&hook->node, &undef_hook);
308 raw_spin_unlock_irqrestore(&undef_lock, flags);
311 void unregister_undef_hook(struct undef_hook *hook)
315 raw_spin_lock_irqsave(&undef_lock, flags);
316 list_del(&hook->node);
317 raw_spin_unlock_irqrestore(&undef_lock, flags);
320 static int call_undef_hook(struct pt_regs *regs)
322 struct undef_hook *hook;
325 int (*fn)(struct pt_regs *regs, u32 instr) = NULL;
326 void __user *pc = (void __user *)instruction_pointer(regs);
328 if (!user_mode(regs))
331 if (compat_thumb_mode(regs)) {
332 /* 16-bit Thumb instruction */
334 if (get_user(instr_le, (__le16 __user *)pc))
336 instr = le16_to_cpu(instr_le);
337 if (aarch32_insn_is_wide(instr)) {
340 if (get_user(instr_le, (__le16 __user *)(pc + 2)))
342 instr2 = le16_to_cpu(instr_le);
343 instr = (instr << 16) | instr2;
346 /* 32-bit ARM instruction */
348 if (get_user(instr_le, (__le32 __user *)pc))
350 instr = le32_to_cpu(instr_le);
353 raw_spin_lock_irqsave(&undef_lock, flags);
354 list_for_each_entry(hook, &undef_hook, node)
355 if ((instr & hook->instr_mask) == hook->instr_val &&
356 (regs->pstate & hook->pstate_mask) == hook->pstate_val)
359 raw_spin_unlock_irqrestore(&undef_lock, flags);
361 return fn ? fn(regs, instr) : 1;
364 void force_signal_inject(int signal, int code, unsigned long address)
367 struct pt_regs *regs = current_pt_regs();
371 desc = "undefined instruction";
374 desc = "illegal memory access";
377 desc = "unknown or unrecoverable error";
381 /* Force signals we don't understand to SIGKILL */
382 if (WARN_ON(signal != SIGKILL &&
383 siginfo_layout(signal, code) != SIL_FAULT)) {
387 arm64_notify_die(desc, regs, signal, code, (void __user *)address, 0);
391 * Set up process info to signal segmentation fault - called on access error.
393 void arm64_notify_segfault(unsigned long addr)
397 down_read(¤t->mm->mmap_sem);
398 if (find_vma(current->mm, addr) == NULL)
402 up_read(¤t->mm->mmap_sem);
404 force_signal_inject(SIGSEGV, code, addr);
407 asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
409 /* check for AArch32 breakpoint instructions */
410 if (!aarch32_break_handler(regs))
413 if (call_undef_hook(regs) == 0)
416 force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc);
419 void cpu_enable_cache_maint_trap(const struct arm64_cpu_capabilities *__unused)
421 sysreg_clear_set(sctlr_el1, SCTLR_EL1_UCI, 0);
424 #define __user_cache_maint(insn, address, res) \
425 if (address >= user_addr_max()) { \
428 uaccess_ttbr0_enable(); \
430 "1: " insn ", %1\n" \
433 " .pushsection .fixup,\"ax\"\n" \
435 "3: mov %w0, %w2\n" \
438 _ASM_EXTABLE(1b, 3b) \
440 : "r" (address), "i" (-EFAULT)); \
441 uaccess_ttbr0_disable(); \
444 static void user_cache_maint_handler(unsigned int esr, struct pt_regs *regs)
446 unsigned long address;
447 int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
448 int crm = (esr & ESR_ELx_SYS64_ISS_CRM_MASK) >> ESR_ELx_SYS64_ISS_CRM_SHIFT;
451 address = untagged_addr(pt_regs_read_reg(regs, rt));
454 case ESR_ELx_SYS64_ISS_CRM_DC_CVAU: /* DC CVAU, gets promoted */
455 __user_cache_maint("dc civac", address, ret);
457 case ESR_ELx_SYS64_ISS_CRM_DC_CVAC: /* DC CVAC, gets promoted */
458 __user_cache_maint("dc civac", address, ret);
460 case ESR_ELx_SYS64_ISS_CRM_DC_CVAP: /* DC CVAP */
461 __user_cache_maint("sys 3, c7, c12, 1", address, ret);
463 case ESR_ELx_SYS64_ISS_CRM_DC_CIVAC: /* DC CIVAC */
464 __user_cache_maint("dc civac", address, ret);
466 case ESR_ELx_SYS64_ISS_CRM_IC_IVAU: /* IC IVAU */
467 __user_cache_maint("ic ivau", address, ret);
470 force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc);
475 arm64_notify_segfault(address);
477 arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
480 static void ctr_read_handler(unsigned int esr, struct pt_regs *regs)
482 int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
483 unsigned long val = arm64_ftr_reg_user_value(&arm64_ftr_reg_ctrel0);
485 pt_regs_write_reg(regs, rt, val);
487 arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
490 static void cntvct_read_handler(unsigned int esr, struct pt_regs *regs)
492 int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
494 pt_regs_write_reg(regs, rt, arch_counter_get_cntvct());
495 arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
498 static void cntfrq_read_handler(unsigned int esr, struct pt_regs *regs)
500 int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
502 pt_regs_write_reg(regs, rt, arch_timer_get_rate());
503 arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
507 unsigned int esr_mask;
508 unsigned int esr_val;
509 void (*handler)(unsigned int esr, struct pt_regs *regs);
512 static struct sys64_hook sys64_hooks[] = {
514 .esr_mask = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_MASK,
515 .esr_val = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_VAL,
516 .handler = user_cache_maint_handler,
519 /* Trap read access to CTR_EL0 */
520 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
521 .esr_val = ESR_ELx_SYS64_ISS_SYS_CTR_READ,
522 .handler = ctr_read_handler,
525 /* Trap read access to CNTVCT_EL0 */
526 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
527 .esr_val = ESR_ELx_SYS64_ISS_SYS_CNTVCT,
528 .handler = cntvct_read_handler,
531 /* Trap read access to CNTFRQ_EL0 */
532 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
533 .esr_val = ESR_ELx_SYS64_ISS_SYS_CNTFRQ,
534 .handler = cntfrq_read_handler,
539 asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
541 struct sys64_hook *hook;
543 for (hook = sys64_hooks; hook->handler; hook++)
544 if ((hook->esr_mask & esr) == hook->esr_val) {
545 hook->handler(esr, regs);
550 * New SYS instructions may previously have been undefined at EL0. Fall
551 * back to our usual undefined instruction handler so that we handle
552 * these consistently.
557 static const char *esr_class_str[] = {
558 [0 ... ESR_ELx_EC_MAX] = "UNRECOGNIZED EC",
559 [ESR_ELx_EC_UNKNOWN] = "Unknown/Uncategorized",
560 [ESR_ELx_EC_WFx] = "WFI/WFE",
561 [ESR_ELx_EC_CP15_32] = "CP15 MCR/MRC",
562 [ESR_ELx_EC_CP15_64] = "CP15 MCRR/MRRC",
563 [ESR_ELx_EC_CP14_MR] = "CP14 MCR/MRC",
564 [ESR_ELx_EC_CP14_LS] = "CP14 LDC/STC",
565 [ESR_ELx_EC_FP_ASIMD] = "ASIMD",
566 [ESR_ELx_EC_CP10_ID] = "CP10 MRC/VMRS",
567 [ESR_ELx_EC_CP14_64] = "CP14 MCRR/MRRC",
568 [ESR_ELx_EC_ILL] = "PSTATE.IL",
569 [ESR_ELx_EC_SVC32] = "SVC (AArch32)",
570 [ESR_ELx_EC_HVC32] = "HVC (AArch32)",
571 [ESR_ELx_EC_SMC32] = "SMC (AArch32)",
572 [ESR_ELx_EC_SVC64] = "SVC (AArch64)",
573 [ESR_ELx_EC_HVC64] = "HVC (AArch64)",
574 [ESR_ELx_EC_SMC64] = "SMC (AArch64)",
575 [ESR_ELx_EC_SYS64] = "MSR/MRS (AArch64)",
576 [ESR_ELx_EC_SVE] = "SVE",
577 [ESR_ELx_EC_IMP_DEF] = "EL3 IMP DEF",
578 [ESR_ELx_EC_IABT_LOW] = "IABT (lower EL)",
579 [ESR_ELx_EC_IABT_CUR] = "IABT (current EL)",
580 [ESR_ELx_EC_PC_ALIGN] = "PC Alignment",
581 [ESR_ELx_EC_DABT_LOW] = "DABT (lower EL)",
582 [ESR_ELx_EC_DABT_CUR] = "DABT (current EL)",
583 [ESR_ELx_EC_SP_ALIGN] = "SP Alignment",
584 [ESR_ELx_EC_FP_EXC32] = "FP (AArch32)",
585 [ESR_ELx_EC_FP_EXC64] = "FP (AArch64)",
586 [ESR_ELx_EC_SERROR] = "SError",
587 [ESR_ELx_EC_BREAKPT_LOW] = "Breakpoint (lower EL)",
588 [ESR_ELx_EC_BREAKPT_CUR] = "Breakpoint (current EL)",
589 [ESR_ELx_EC_SOFTSTP_LOW] = "Software Step (lower EL)",
590 [ESR_ELx_EC_SOFTSTP_CUR] = "Software Step (current EL)",
591 [ESR_ELx_EC_WATCHPT_LOW] = "Watchpoint (lower EL)",
592 [ESR_ELx_EC_WATCHPT_CUR] = "Watchpoint (current EL)",
593 [ESR_ELx_EC_BKPT32] = "BKPT (AArch32)",
594 [ESR_ELx_EC_VECTOR32] = "Vector catch (AArch32)",
595 [ESR_ELx_EC_BRK64] = "BRK (AArch64)",
598 const char *esr_get_class_string(u32 esr)
600 return esr_class_str[ESR_ELx_EC(esr)];
604 * bad_mode handles the impossible case in the exception vector. This is always
607 asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
611 pr_crit("Bad mode in %s handler detected on CPU%d, code 0x%08x -- %s\n",
612 handler[reason], smp_processor_id(), esr,
613 esr_get_class_string(esr));
615 die("Oops - bad mode", regs, 0);
621 * bad_el0_sync handles unexpected, but potentially recoverable synchronous
622 * exceptions taken from EL0. Unlike bad_mode, this returns.
624 asmlinkage void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr)
626 void __user *pc = (void __user *)instruction_pointer(regs);
628 current->thread.fault_address = 0;
629 current->thread.fault_code = esr;
631 arm64_force_sig_fault(SIGILL, ILL_ILLOPC, pc,
632 "Bad EL0 synchronous exception");
635 #ifdef CONFIG_VMAP_STACK
637 DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack)
640 asmlinkage void handle_bad_stack(struct pt_regs *regs)
642 unsigned long tsk_stk = (unsigned long)current->stack;
643 unsigned long irq_stk = (unsigned long)this_cpu_read(irq_stack_ptr);
644 unsigned long ovf_stk = (unsigned long)this_cpu_ptr(overflow_stack);
645 unsigned int esr = read_sysreg(esr_el1);
646 unsigned long far = read_sysreg(far_el1);
649 pr_emerg("Insufficient stack space to handle exception!");
651 pr_emerg("ESR: 0x%08x -- %s\n", esr, esr_get_class_string(esr));
652 pr_emerg("FAR: 0x%016lx\n", far);
654 pr_emerg("Task stack: [0x%016lx..0x%016lx]\n",
655 tsk_stk, tsk_stk + THREAD_SIZE);
656 pr_emerg("IRQ stack: [0x%016lx..0x%016lx]\n",
657 irq_stk, irq_stk + THREAD_SIZE);
658 pr_emerg("Overflow stack: [0x%016lx..0x%016lx]\n",
659 ovf_stk, ovf_stk + OVERFLOW_STACK_SIZE);
664 * We use nmi_panic to limit the potential for recusive overflows, and
665 * to get a better stack trace.
667 nmi_panic(NULL, "kernel stack overflow");
672 void __noreturn arm64_serror_panic(struct pt_regs *regs, u32 esr)
676 pr_crit("SError Interrupt on CPU%d, code 0x%08x -- %s\n",
677 smp_processor_id(), esr, esr_get_class_string(esr));
681 nmi_panic(regs, "Asynchronous SError Interrupt");
687 bool arm64_is_fatal_ras_serror(struct pt_regs *regs, unsigned int esr)
689 u32 aet = arm64_ras_serror_get_severity(esr);
692 case ESR_ELx_AET_CE: /* corrected error */
693 case ESR_ELx_AET_UEO: /* restartable, not yet consumed */
695 * The CPU can make progress. We may take UEO again as
696 * a more severe error.
700 case ESR_ELx_AET_UEU: /* Uncorrected Unrecoverable */
701 case ESR_ELx_AET_UER: /* Uncorrected Recoverable */
703 * The CPU can't make progress. The exception may have
708 case ESR_ELx_AET_UC: /* Uncontainable or Uncategorized error */
710 /* Error has been silently propagated */
711 arm64_serror_panic(regs, esr);
715 asmlinkage void do_serror(struct pt_regs *regs, unsigned int esr)
719 /* non-RAS errors are not containable */
720 if (!arm64_is_ras_serror(esr) || arm64_is_fatal_ras_serror(regs, esr))
721 arm64_serror_panic(regs, esr);
726 void __pte_error(const char *file, int line, unsigned long val)
728 pr_err("%s:%d: bad pte %016lx.\n", file, line, val);
731 void __pmd_error(const char *file, int line, unsigned long val)
733 pr_err("%s:%d: bad pmd %016lx.\n", file, line, val);
736 void __pud_error(const char *file, int line, unsigned long val)
738 pr_err("%s:%d: bad pud %016lx.\n", file, line, val);
741 void __pgd_error(const char *file, int line, unsigned long val)
743 pr_err("%s:%d: bad pgd %016lx.\n", file, line, val);
746 /* GENERIC_BUG traps */
748 int is_valid_bugaddr(unsigned long addr)
751 * bug_handler() only called for BRK #BUG_BRK_IMM.
752 * So the answer is trivial -- any spurious instances with no
753 * bug table entry will be rejected by report_bug() and passed
754 * back to the debug-monitors code and handled as a fatal
755 * unexpected debug exception.
760 static int bug_handler(struct pt_regs *regs, unsigned int esr)
763 return DBG_HOOK_ERROR;
765 switch (report_bug(regs->pc, regs)) {
766 case BUG_TRAP_TYPE_BUG:
767 die("Oops - BUG", regs, 0);
770 case BUG_TRAP_TYPE_WARN:
774 /* unknown/unrecognised bug trap type */
775 return DBG_HOOK_ERROR;
778 /* If thread survives, skip over the BUG instruction and continue: */
779 arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
780 return DBG_HOOK_HANDLED;
783 static struct break_hook bug_break_hook = {
784 .esr_val = 0xf2000000 | BUG_BRK_IMM,
785 .esr_mask = 0xffffffff,
790 * Initial handler for AArch64 BRK exceptions
791 * This handler only used until debug_traps_init().
793 int __init early_brk64(unsigned long addr, unsigned int esr,
794 struct pt_regs *regs)
796 return bug_handler(regs, esr) != DBG_HOOK_HANDLED;
799 /* This registration must happen early, before debug_traps_init(). */
800 void __init trap_init(void)
802 register_break_hook(&bug_break_hook);