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/syscalls.h>
36 #include <linux/mm_types.h>
38 #include <asm/atomic.h>
40 #include <asm/debug-monitors.h>
43 #include <asm/traps.h>
44 #include <asm/stack_pointer.h>
45 #include <asm/stacktrace.h>
46 #include <asm/exception.h>
47 #include <asm/system_misc.h>
48 #include <asm/sysreg.h>
50 static const char *handler[]= {
57 int show_unhandled_signals = 1;
60 * Dump out the contents of some kernel memory nicely...
62 static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
70 * We need to switch to kernel mode so that we can use __get_user
71 * to safely read from kernel space.
76 printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top);
78 for (first = bottom & ~31; first < top; first += 32) {
80 char str[sizeof(" 12345678") * 8 + 1];
82 memset(str, ' ', sizeof(str));
83 str[sizeof(str) - 1] = '\0';
85 for (p = first, i = 0; i < (32 / 8)
86 && p < top; i++, p += 8) {
87 if (p >= bottom && p < top) {
90 if (__get_user(val, (unsigned long *)p) == 0)
91 sprintf(str + i * 17, " %016lx", val);
93 sprintf(str + i * 17, " ????????????????");
96 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
102 static void dump_backtrace_entry(unsigned long where)
105 * Note that 'where' can have a physical address, but it's not handled.
110 static void __dump_instr(const char *lvl, struct pt_regs *regs)
112 unsigned long addr = instruction_pointer(regs);
113 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
116 for (i = -4; i < 1; i++) {
117 unsigned int val, bad;
119 bad = __get_user(val, &((u32 *)addr)[i]);
122 p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
124 p += sprintf(p, "bad PC value");
128 printk("%sCode: %s\n", lvl, str);
131 static void dump_instr(const char *lvl, struct pt_regs *regs)
133 if (!user_mode(regs)) {
134 mm_segment_t fs = get_fs();
136 __dump_instr(lvl, regs);
139 __dump_instr(lvl, regs);
143 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
145 struct stackframe frame;
146 unsigned long irq_stack_ptr;
149 pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
154 if (!try_get_task_stack(tsk))
158 * Switching between stacks is valid when tracing current and in
159 * non-preemptible context.
161 if (tsk == current && !preemptible())
162 irq_stack_ptr = IRQ_STACK_PTR(smp_processor_id());
166 if (tsk == current) {
167 frame.fp = (unsigned long)__builtin_frame_address(0);
168 frame.sp = current_stack_pointer;
169 frame.pc = (unsigned long)dump_backtrace;
172 * task blocked in __switch_to
174 frame.fp = thread_saved_fp(tsk);
175 frame.sp = thread_saved_sp(tsk);
176 frame.pc = thread_saved_pc(tsk);
178 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
179 frame.graph = tsk->curr_ret_stack;
183 printk("Call trace:\n");
185 unsigned long where = frame.pc;
189 /* skip until specified stack frame */
191 dump_backtrace_entry(where);
192 } else if (frame.fp == regs->regs[29]) {
195 * Mostly, this is the case where this function is
196 * called in panic/abort. As exception handler's
197 * stack frame does not contain the corresponding pc
198 * at which an exception has taken place, use regs->pc
201 dump_backtrace_entry(regs->pc);
203 ret = unwind_frame(tsk, &frame);
207 if (in_exception_text(where)) {
209 * If we switched to the irq_stack before calling this
210 * exception handler, then the pt_regs will be on the
211 * task stack. The easiest way to tell is if the large
212 * pt_regs would overlap with the end of the irq_stack.
214 if (stack < irq_stack_ptr &&
215 (stack + sizeof(struct pt_regs)) > irq_stack_ptr)
216 stack = IRQ_STACK_TO_TASK_STACK(irq_stack_ptr);
218 dump_mem("", "Exception stack", stack,
219 stack + sizeof(struct pt_regs));
226 void show_stack(struct task_struct *tsk, unsigned long *sp)
228 dump_backtrace(NULL, tsk);
232 #ifdef CONFIG_PREEMPT
233 #define S_PREEMPT " PREEMPT"
239 static int __die(const char *str, int err, struct pt_regs *regs)
241 struct task_struct *tsk = current;
242 static int die_counter;
245 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
246 str, err, ++die_counter);
248 /* trap and error numbers are mostly meaningless on ARM */
249 ret = notify_die(DIE_OOPS, str, regs, err, 0, SIGSEGV);
250 if (ret == NOTIFY_STOP)
255 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
256 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk),
259 if (!user_mode(regs)) {
260 dump_mem(KERN_EMERG, "Stack: ", regs->sp,
261 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
262 dump_backtrace(regs, tsk);
263 dump_instr(KERN_EMERG, regs);
269 static DEFINE_RAW_SPINLOCK(die_lock);
272 * This function is protected against re-entrancy.
274 void die(const char *str, struct pt_regs *regs, int err)
280 raw_spin_lock_irq(&die_lock);
283 ret = __die(str, err, regs);
285 if (regs && kexec_should_crash(current))
289 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
290 raw_spin_unlock_irq(&die_lock);
294 panic("Fatal exception in interrupt");
296 panic("Fatal exception");
297 if (ret != NOTIFY_STOP)
301 void arm64_notify_die(const char *str, struct pt_regs *regs,
302 struct siginfo *info, int err)
304 if (user_mode(regs)) {
305 current->thread.fault_address = 0;
306 current->thread.fault_code = err;
307 force_sig_info(info->si_signo, info, current);
313 static LIST_HEAD(undef_hook);
314 static DEFINE_RAW_SPINLOCK(undef_lock);
316 void register_undef_hook(struct undef_hook *hook)
320 raw_spin_lock_irqsave(&undef_lock, flags);
321 list_add(&hook->node, &undef_hook);
322 raw_spin_unlock_irqrestore(&undef_lock, flags);
325 void unregister_undef_hook(struct undef_hook *hook)
329 raw_spin_lock_irqsave(&undef_lock, flags);
330 list_del(&hook->node);
331 raw_spin_unlock_irqrestore(&undef_lock, flags);
334 static int call_undef_hook(struct pt_regs *regs)
336 struct undef_hook *hook;
339 int (*fn)(struct pt_regs *regs, u32 instr) = NULL;
340 void __user *pc = (void __user *)instruction_pointer(regs);
342 if (!user_mode(regs))
345 if (compat_thumb_mode(regs)) {
346 /* 16-bit Thumb instruction */
347 if (get_user(instr, (u16 __user *)pc))
349 instr = le16_to_cpu(instr);
350 if (aarch32_insn_is_wide(instr)) {
353 if (get_user(instr2, (u16 __user *)(pc + 2)))
355 instr2 = le16_to_cpu(instr2);
356 instr = (instr << 16) | instr2;
359 /* 32-bit ARM instruction */
360 if (get_user(instr, (u32 __user *)pc))
362 instr = le32_to_cpu(instr);
365 raw_spin_lock_irqsave(&undef_lock, flags);
366 list_for_each_entry(hook, &undef_hook, node)
367 if ((instr & hook->instr_mask) == hook->instr_val &&
368 (regs->pstate & hook->pstate_mask) == hook->pstate_val)
371 raw_spin_unlock_irqrestore(&undef_lock, flags);
373 return fn ? fn(regs, instr) : 1;
376 static void force_signal_inject(int signal, int code, struct pt_regs *regs,
377 unsigned long address)
380 void __user *pc = (void __user *)instruction_pointer(regs);
385 desc = "undefined instruction";
388 desc = "illegal memory access";
395 if (unhandled_signal(current, signal) &&
396 show_unhandled_signals_ratelimited()) {
397 pr_info("%s[%d]: %s: pc=%p\n",
398 current->comm, task_pid_nr(current), desc, pc);
399 dump_instr(KERN_INFO, regs);
402 info.si_signo = signal;
407 arm64_notify_die(desc, regs, &info, 0);
411 * Set up process info to signal segmentation fault - called on access error.
413 void arm64_notify_segfault(struct pt_regs *regs, unsigned long addr)
417 down_read(¤t->mm->mmap_sem);
418 if (find_vma(current->mm, addr) == NULL)
422 up_read(¤t->mm->mmap_sem);
424 force_signal_inject(SIGSEGV, code, regs, addr);
427 asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
429 /* check for AArch32 breakpoint instructions */
430 if (!aarch32_break_handler(regs))
433 if (call_undef_hook(regs) == 0)
436 force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
439 int cpu_enable_cache_maint_trap(void *__unused)
441 config_sctlr_el1(SCTLR_EL1_UCI, 0);
445 #define __user_cache_maint(insn, address, res) \
446 if (untagged_addr(address) >= user_addr_max()) { \
449 uaccess_ttbr0_enable(); \
451 "1: " insn ", %1\n" \
454 " .pushsection .fixup,\"ax\"\n" \
456 "3: mov %w0, %w2\n" \
459 _ASM_EXTABLE(1b, 3b) \
461 : "r" (address), "i" (-EFAULT)); \
462 uaccess_ttbr0_disable(); \
465 static void user_cache_maint_handler(unsigned int esr, struct pt_regs *regs)
467 unsigned long address;
468 int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
469 int crm = (esr & ESR_ELx_SYS64_ISS_CRM_MASK) >> ESR_ELx_SYS64_ISS_CRM_SHIFT;
472 address = pt_regs_read_reg(regs, rt);
475 case ESR_ELx_SYS64_ISS_CRM_DC_CVAU: /* DC CVAU, gets promoted */
476 __user_cache_maint("dc civac", address, ret);
478 case ESR_ELx_SYS64_ISS_CRM_DC_CVAC: /* DC CVAC, gets promoted */
479 __user_cache_maint("dc civac", address, ret);
481 case ESR_ELx_SYS64_ISS_CRM_DC_CIVAC: /* DC CIVAC */
482 __user_cache_maint("dc civac", address, ret);
484 case ESR_ELx_SYS64_ISS_CRM_IC_IVAU: /* IC IVAU */
485 __user_cache_maint("ic ivau", address, ret);
488 force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
493 arm64_notify_segfault(regs, address);
498 static void ctr_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;
501 unsigned long val = arm64_ftr_reg_user_value(&arm64_ftr_reg_ctrel0);
503 pt_regs_write_reg(regs, rt, val);
508 static void cntvct_read_handler(unsigned int esr, struct pt_regs *regs)
510 int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
512 pt_regs_write_reg(regs, rt, arch_counter_get_cntvct());
516 static void cntfrq_read_handler(unsigned int esr, struct pt_regs *regs)
518 int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
520 pt_regs_write_reg(regs, rt, read_sysreg(cntfrq_el0));
525 unsigned int esr_mask;
526 unsigned int esr_val;
527 void (*handler)(unsigned int esr, struct pt_regs *regs);
530 static struct sys64_hook sys64_hooks[] = {
532 .esr_mask = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_MASK,
533 .esr_val = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_VAL,
534 .handler = user_cache_maint_handler,
537 /* Trap read access to CTR_EL0 */
538 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
539 .esr_val = ESR_ELx_SYS64_ISS_SYS_CTR_READ,
540 .handler = ctr_read_handler,
543 /* Trap read access to CNTVCT_EL0 */
544 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
545 .esr_val = ESR_ELx_SYS64_ISS_SYS_CNTVCT,
546 .handler = cntvct_read_handler,
549 /* Trap read access to CNTFRQ_EL0 */
550 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
551 .esr_val = ESR_ELx_SYS64_ISS_SYS_CNTFRQ,
552 .handler = cntfrq_read_handler,
557 asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
559 struct sys64_hook *hook;
561 for (hook = sys64_hooks; hook->handler; hook++)
562 if ((hook->esr_mask & esr) == hook->esr_val) {
563 hook->handler(esr, regs);
568 * New SYS instructions may previously have been undefined at EL0. Fall
569 * back to our usual undefined instruction handler so that we handle
570 * these consistently.
575 long compat_arm_syscall(struct pt_regs *regs);
577 asmlinkage long do_ni_syscall(struct pt_regs *regs)
581 if (is_compat_task()) {
582 ret = compat_arm_syscall(regs);
588 if (show_unhandled_signals_ratelimited()) {
589 pr_info("%s[%d]: syscall %d\n", current->comm,
590 task_pid_nr(current), (int)regs->syscallno);
591 dump_instr("", regs);
596 return sys_ni_syscall();
599 static const char *esr_class_str[] = {
600 [0 ... ESR_ELx_EC_MAX] = "UNRECOGNIZED EC",
601 [ESR_ELx_EC_UNKNOWN] = "Unknown/Uncategorized",
602 [ESR_ELx_EC_WFx] = "WFI/WFE",
603 [ESR_ELx_EC_CP15_32] = "CP15 MCR/MRC",
604 [ESR_ELx_EC_CP15_64] = "CP15 MCRR/MRRC",
605 [ESR_ELx_EC_CP14_MR] = "CP14 MCR/MRC",
606 [ESR_ELx_EC_CP14_LS] = "CP14 LDC/STC",
607 [ESR_ELx_EC_FP_ASIMD] = "ASIMD",
608 [ESR_ELx_EC_CP10_ID] = "CP10 MRC/VMRS",
609 [ESR_ELx_EC_CP14_64] = "CP14 MCRR/MRRC",
610 [ESR_ELx_EC_ILL] = "PSTATE.IL",
611 [ESR_ELx_EC_SVC32] = "SVC (AArch32)",
612 [ESR_ELx_EC_HVC32] = "HVC (AArch32)",
613 [ESR_ELx_EC_SMC32] = "SMC (AArch32)",
614 [ESR_ELx_EC_SVC64] = "SVC (AArch64)",
615 [ESR_ELx_EC_HVC64] = "HVC (AArch64)",
616 [ESR_ELx_EC_SMC64] = "SMC (AArch64)",
617 [ESR_ELx_EC_SYS64] = "MSR/MRS (AArch64)",
618 [ESR_ELx_EC_IMP_DEF] = "EL3 IMP DEF",
619 [ESR_ELx_EC_IABT_LOW] = "IABT (lower EL)",
620 [ESR_ELx_EC_IABT_CUR] = "IABT (current EL)",
621 [ESR_ELx_EC_PC_ALIGN] = "PC Alignment",
622 [ESR_ELx_EC_DABT_LOW] = "DABT (lower EL)",
623 [ESR_ELx_EC_DABT_CUR] = "DABT (current EL)",
624 [ESR_ELx_EC_SP_ALIGN] = "SP Alignment",
625 [ESR_ELx_EC_FP_EXC32] = "FP (AArch32)",
626 [ESR_ELx_EC_FP_EXC64] = "FP (AArch64)",
627 [ESR_ELx_EC_SERROR] = "SError",
628 [ESR_ELx_EC_BREAKPT_LOW] = "Breakpoint (lower EL)",
629 [ESR_ELx_EC_BREAKPT_CUR] = "Breakpoint (current EL)",
630 [ESR_ELx_EC_SOFTSTP_LOW] = "Software Step (lower EL)",
631 [ESR_ELx_EC_SOFTSTP_CUR] = "Software Step (current EL)",
632 [ESR_ELx_EC_WATCHPT_LOW] = "Watchpoint (lower EL)",
633 [ESR_ELx_EC_WATCHPT_CUR] = "Watchpoint (current EL)",
634 [ESR_ELx_EC_BKPT32] = "BKPT (AArch32)",
635 [ESR_ELx_EC_VECTOR32] = "Vector catch (AArch32)",
636 [ESR_ELx_EC_BRK64] = "BRK (AArch64)",
639 const char *esr_get_class_string(u32 esr)
641 return esr_class_str[ESR_ELx_EC(esr)];
645 * bad_mode handles the impossible case in the exception vector. This is always
648 asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
652 pr_crit("Bad mode in %s handler detected on CPU%d, code 0x%08x -- %s\n",
653 handler[reason], smp_processor_id(), esr,
654 esr_get_class_string(esr));
656 die("Oops - bad mode", regs, 0);
662 * bad_el0_sync handles unexpected, but potentially recoverable synchronous
663 * exceptions taken from EL0. Unlike bad_mode, this returns.
665 asmlinkage void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr)
668 void __user *pc = (void __user *)instruction_pointer(regs);
671 pr_crit("Bad EL0 synchronous exception detected on CPU%d, code 0x%08x -- %s\n",
672 smp_processor_id(), esr, esr_get_class_string(esr));
675 info.si_signo = SIGILL;
677 info.si_code = ILL_ILLOPC;
680 current->thread.fault_address = 0;
681 current->thread.fault_code = 0;
683 force_sig_info(info.si_signo, &info, current);
686 void __pte_error(const char *file, int line, unsigned long val)
688 pr_err("%s:%d: bad pte %016lx.\n", file, line, val);
691 void __pmd_error(const char *file, int line, unsigned long val)
693 pr_err("%s:%d: bad pmd %016lx.\n", file, line, val);
696 void __pud_error(const char *file, int line, unsigned long val)
698 pr_err("%s:%d: bad pud %016lx.\n", file, line, val);
701 void __pgd_error(const char *file, int line, unsigned long val)
703 pr_err("%s:%d: bad pgd %016lx.\n", file, line, val);
706 /* GENERIC_BUG traps */
708 int is_valid_bugaddr(unsigned long addr)
711 * bug_handler() only called for BRK #BUG_BRK_IMM.
712 * So the answer is trivial -- any spurious instances with no
713 * bug table entry will be rejected by report_bug() and passed
714 * back to the debug-monitors code and handled as a fatal
715 * unexpected debug exception.
720 static int bug_handler(struct pt_regs *regs, unsigned int esr)
723 return DBG_HOOK_ERROR;
725 switch (report_bug(regs->pc, regs)) {
726 case BUG_TRAP_TYPE_BUG:
727 die("Oops - BUG", regs, 0);
730 case BUG_TRAP_TYPE_WARN:
731 /* Ideally, report_bug() should backtrace for us... but no. */
732 dump_backtrace(regs, NULL);
736 /* unknown/unrecognised bug trap type */
737 return DBG_HOOK_ERROR;
740 /* If thread survives, skip over the BUG instruction and continue: */
741 regs->pc += AARCH64_INSN_SIZE; /* skip BRK and resume */
742 return DBG_HOOK_HANDLED;
745 static struct break_hook bug_break_hook = {
746 .esr_val = 0xf2000000 | BUG_BRK_IMM,
747 .esr_mask = 0xffffffff,
752 * Initial handler for AArch64 BRK exceptions
753 * This handler only used until debug_traps_init().
755 int __init early_brk64(unsigned long addr, unsigned int esr,
756 struct pt_regs *regs)
758 return bug_handler(regs, esr) != DBG_HOOK_HANDLED;
761 /* This registration must happen early, before debug_traps_init(). */
762 void __init trap_init(void)
764 register_break_hook(&bug_break_hook);