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>
37 #include <asm/atomic.h>
39 #include <asm/debug-monitors.h>
42 #include <asm/traps.h>
43 #include <asm/stack_pointer.h>
44 #include <asm/stacktrace.h>
45 #include <asm/exception.h>
46 #include <asm/system_misc.h>
47 #include <asm/sysreg.h>
49 static const char *handler[]= {
56 int show_unhandled_signals = 1;
59 * Dump out the contents of some kernel memory nicely...
61 static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
69 * We need to switch to kernel mode so that we can use __get_user
70 * to safely read from kernel space.
75 printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top);
77 for (first = bottom & ~31; first < top; first += 32) {
79 char str[sizeof(" 12345678") * 8 + 1];
81 memset(str, ' ', sizeof(str));
82 str[sizeof(str) - 1] = '\0';
84 for (p = first, i = 0; i < (32 / 8)
85 && p < top; i++, p += 8) {
86 if (p >= bottom && p < top) {
89 if (__get_user(val, (unsigned long *)p) == 0)
90 sprintf(str + i * 17, " %016lx", val);
92 sprintf(str + i * 17, " ????????????????");
95 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
101 static void dump_backtrace_entry(unsigned long where)
104 * Note that 'where' can have a physical address, but it's not handled.
109 static void __dump_instr(const char *lvl, struct pt_regs *regs)
111 unsigned long addr = instruction_pointer(regs);
112 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
115 for (i = -4; i < 1; i++) {
116 unsigned int val, bad;
118 bad = __get_user(val, &((u32 *)addr)[i]);
121 p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
123 p += sprintf(p, "bad PC value");
127 printk("%sCode: %s\n", lvl, str);
130 static void dump_instr(const char *lvl, struct pt_regs *regs)
132 if (!user_mode(regs)) {
133 mm_segment_t fs = get_fs();
135 __dump_instr(lvl, regs);
138 __dump_instr(lvl, regs);
142 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
144 struct stackframe frame;
145 unsigned long irq_stack_ptr;
148 pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
153 if (!try_get_task_stack(tsk))
157 * Switching between stacks is valid when tracing current and in
158 * non-preemptible context.
160 if (tsk == current && !preemptible())
161 irq_stack_ptr = IRQ_STACK_PTR(smp_processor_id());
165 if (tsk == current) {
166 frame.fp = (unsigned long)__builtin_frame_address(0);
167 frame.sp = current_stack_pointer;
168 frame.pc = (unsigned long)dump_backtrace;
171 * task blocked in __switch_to
173 frame.fp = thread_saved_fp(tsk);
174 frame.sp = thread_saved_sp(tsk);
175 frame.pc = thread_saved_pc(tsk);
177 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
178 frame.graph = tsk->curr_ret_stack;
182 printk("Call trace:\n");
184 unsigned long where = frame.pc;
188 /* skip until specified stack frame */
190 dump_backtrace_entry(where);
191 } else if (frame.fp == regs->regs[29]) {
194 * Mostly, this is the case where this function is
195 * called in panic/abort. As exception handler's
196 * stack frame does not contain the corresponding pc
197 * at which an exception has taken place, use regs->pc
200 dump_backtrace_entry(regs->pc);
202 ret = unwind_frame(tsk, &frame);
206 if (in_exception_text(where)) {
208 * If we switched to the irq_stack before calling this
209 * exception handler, then the pt_regs will be on the
210 * task stack. The easiest way to tell is if the large
211 * pt_regs would overlap with the end of the irq_stack.
213 if (stack < irq_stack_ptr &&
214 (stack + sizeof(struct pt_regs)) > irq_stack_ptr)
215 stack = IRQ_STACK_TO_TASK_STACK(irq_stack_ptr);
217 dump_mem("", "Exception stack", stack,
218 stack + sizeof(struct pt_regs));
225 void show_stack(struct task_struct *tsk, unsigned long *sp)
227 dump_backtrace(NULL, tsk);
231 #ifdef CONFIG_PREEMPT
232 #define S_PREEMPT " PREEMPT"
238 static int __die(const char *str, int err, struct pt_regs *regs)
240 struct task_struct *tsk = current;
241 static int die_counter;
244 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
245 str, err, ++die_counter);
247 /* trap and error numbers are mostly meaningless on ARM */
248 ret = notify_die(DIE_OOPS, str, regs, err, 0, SIGSEGV);
249 if (ret == NOTIFY_STOP)
254 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
255 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk),
258 if (!user_mode(regs)) {
259 dump_mem(KERN_EMERG, "Stack: ", regs->sp,
260 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
261 dump_backtrace(regs, tsk);
262 dump_instr(KERN_EMERG, regs);
268 static DEFINE_RAW_SPINLOCK(die_lock);
271 * This function is protected against re-entrancy.
273 void die(const char *str, struct pt_regs *regs, int err)
279 raw_spin_lock_irq(&die_lock);
282 ret = __die(str, err, regs);
284 if (regs && kexec_should_crash(current))
288 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
289 raw_spin_unlock_irq(&die_lock);
293 panic("Fatal exception in interrupt");
295 panic("Fatal exception");
296 if (ret != NOTIFY_STOP)
300 void arm64_notify_die(const char *str, struct pt_regs *regs,
301 struct siginfo *info, int err)
303 if (user_mode(regs)) {
304 current->thread.fault_address = 0;
305 current->thread.fault_code = err;
306 force_sig_info(info->si_signo, info, current);
312 static LIST_HEAD(undef_hook);
313 static DEFINE_RAW_SPINLOCK(undef_lock);
315 void register_undef_hook(struct undef_hook *hook)
319 raw_spin_lock_irqsave(&undef_lock, flags);
320 list_add(&hook->node, &undef_hook);
321 raw_spin_unlock_irqrestore(&undef_lock, flags);
324 void unregister_undef_hook(struct undef_hook *hook)
328 raw_spin_lock_irqsave(&undef_lock, flags);
329 list_del(&hook->node);
330 raw_spin_unlock_irqrestore(&undef_lock, flags);
333 static int call_undef_hook(struct pt_regs *regs)
335 struct undef_hook *hook;
338 int (*fn)(struct pt_regs *regs, u32 instr) = NULL;
339 void __user *pc = (void __user *)instruction_pointer(regs);
341 if (!user_mode(regs))
344 if (compat_thumb_mode(regs)) {
345 /* 16-bit Thumb instruction */
346 if (get_user(instr, (u16 __user *)pc))
348 instr = le16_to_cpu(instr);
349 if (aarch32_insn_is_wide(instr)) {
352 if (get_user(instr2, (u16 __user *)(pc + 2)))
354 instr2 = le16_to_cpu(instr2);
355 instr = (instr << 16) | instr2;
358 /* 32-bit ARM instruction */
359 if (get_user(instr, (u32 __user *)pc))
361 instr = le32_to_cpu(instr);
364 raw_spin_lock_irqsave(&undef_lock, flags);
365 list_for_each_entry(hook, &undef_hook, node)
366 if ((instr & hook->instr_mask) == hook->instr_val &&
367 (regs->pstate & hook->pstate_mask) == hook->pstate_val)
370 raw_spin_unlock_irqrestore(&undef_lock, flags);
372 return fn ? fn(regs, instr) : 1;
375 static void force_signal_inject(int signal, int code, struct pt_regs *regs,
376 unsigned long address)
379 void __user *pc = (void __user *)instruction_pointer(regs);
384 desc = "undefined instruction";
387 desc = "illegal memory access";
394 if (unhandled_signal(current, signal) &&
395 show_unhandled_signals_ratelimited()) {
396 pr_info("%s[%d]: %s: pc=%p\n",
397 current->comm, task_pid_nr(current), desc, pc);
398 dump_instr(KERN_INFO, regs);
401 info.si_signo = signal;
406 arm64_notify_die(desc, regs, &info, 0);
410 * Set up process info to signal segmentation fault - called on access error.
412 void arm64_notify_segfault(struct pt_regs *regs, unsigned long addr)
416 down_read(¤t->mm->mmap_sem);
417 if (find_vma(current->mm, addr) == NULL)
421 up_read(¤t->mm->mmap_sem);
423 force_signal_inject(SIGSEGV, code, regs, addr);
426 asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
428 /* check for AArch32 breakpoint instructions */
429 if (!aarch32_break_handler(regs))
432 if (call_undef_hook(regs) == 0)
435 force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
438 int cpu_enable_cache_maint_trap(void *__unused)
440 config_sctlr_el1(SCTLR_EL1_UCI, 0);
444 #define __user_cache_maint(insn, address, res) \
445 if (untagged_addr(address) >= user_addr_max()) { \
448 uaccess_ttbr0_enable(); \
450 "1: " insn ", %1\n" \
453 " .pushsection .fixup,\"ax\"\n" \
455 "3: mov %w0, %w2\n" \
458 _ASM_EXTABLE(1b, 3b) \
460 : "r" (address), "i" (-EFAULT)); \
461 uaccess_ttbr0_disable(); \
464 static void user_cache_maint_handler(unsigned int esr, struct pt_regs *regs)
466 unsigned long address;
467 int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
468 int crm = (esr & ESR_ELx_SYS64_ISS_CRM_MASK) >> ESR_ELx_SYS64_ISS_CRM_SHIFT;
471 address = pt_regs_read_reg(regs, rt);
474 case ESR_ELx_SYS64_ISS_CRM_DC_CVAU: /* DC CVAU, gets promoted */
475 __user_cache_maint("dc civac", address, ret);
477 case ESR_ELx_SYS64_ISS_CRM_DC_CVAC: /* DC CVAC, gets promoted */
478 __user_cache_maint("dc civac", address, ret);
480 case ESR_ELx_SYS64_ISS_CRM_DC_CIVAC: /* DC CIVAC */
481 __user_cache_maint("dc civac", address, ret);
483 case ESR_ELx_SYS64_ISS_CRM_IC_IVAU: /* IC IVAU */
484 __user_cache_maint("ic ivau", address, ret);
487 force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
492 arm64_notify_segfault(regs, address);
497 static void ctr_read_handler(unsigned int esr, struct pt_regs *regs)
499 int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
500 unsigned long val = arm64_ftr_reg_user_value(&arm64_ftr_reg_ctrel0);
502 pt_regs_write_reg(regs, rt, val);
508 unsigned int esr_mask;
509 unsigned int esr_val;
510 void (*handler)(unsigned int esr, struct pt_regs *regs);
513 static struct sys64_hook sys64_hooks[] = {
515 .esr_mask = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_MASK,
516 .esr_val = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_VAL,
517 .handler = user_cache_maint_handler,
520 /* Trap read access to CTR_EL0 */
521 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
522 .esr_val = ESR_ELx_SYS64_ISS_SYS_CTR_READ,
523 .handler = ctr_read_handler,
528 asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
530 struct sys64_hook *hook;
532 for (hook = sys64_hooks; hook->handler; hook++)
533 if ((hook->esr_mask & esr) == hook->esr_val) {
534 hook->handler(esr, regs);
539 * New SYS instructions may previously have been undefined at EL0. Fall
540 * back to our usual undefined instruction handler so that we handle
541 * these consistently.
546 long compat_arm_syscall(struct pt_regs *regs);
548 asmlinkage long do_ni_syscall(struct pt_regs *regs)
552 if (is_compat_task()) {
553 ret = compat_arm_syscall(regs);
559 if (show_unhandled_signals_ratelimited()) {
560 pr_info("%s[%d]: syscall %d\n", current->comm,
561 task_pid_nr(current), (int)regs->syscallno);
562 dump_instr("", regs);
567 return sys_ni_syscall();
570 static const char *esr_class_str[] = {
571 [0 ... ESR_ELx_EC_MAX] = "UNRECOGNIZED EC",
572 [ESR_ELx_EC_UNKNOWN] = "Unknown/Uncategorized",
573 [ESR_ELx_EC_WFx] = "WFI/WFE",
574 [ESR_ELx_EC_CP15_32] = "CP15 MCR/MRC",
575 [ESR_ELx_EC_CP15_64] = "CP15 MCRR/MRRC",
576 [ESR_ELx_EC_CP14_MR] = "CP14 MCR/MRC",
577 [ESR_ELx_EC_CP14_LS] = "CP14 LDC/STC",
578 [ESR_ELx_EC_FP_ASIMD] = "ASIMD",
579 [ESR_ELx_EC_CP10_ID] = "CP10 MRC/VMRS",
580 [ESR_ELx_EC_CP14_64] = "CP14 MCRR/MRRC",
581 [ESR_ELx_EC_ILL] = "PSTATE.IL",
582 [ESR_ELx_EC_SVC32] = "SVC (AArch32)",
583 [ESR_ELx_EC_HVC32] = "HVC (AArch32)",
584 [ESR_ELx_EC_SMC32] = "SMC (AArch32)",
585 [ESR_ELx_EC_SVC64] = "SVC (AArch64)",
586 [ESR_ELx_EC_HVC64] = "HVC (AArch64)",
587 [ESR_ELx_EC_SMC64] = "SMC (AArch64)",
588 [ESR_ELx_EC_SYS64] = "MSR/MRS (AArch64)",
589 [ESR_ELx_EC_IMP_DEF] = "EL3 IMP DEF",
590 [ESR_ELx_EC_IABT_LOW] = "IABT (lower EL)",
591 [ESR_ELx_EC_IABT_CUR] = "IABT (current EL)",
592 [ESR_ELx_EC_PC_ALIGN] = "PC Alignment",
593 [ESR_ELx_EC_DABT_LOW] = "DABT (lower EL)",
594 [ESR_ELx_EC_DABT_CUR] = "DABT (current EL)",
595 [ESR_ELx_EC_SP_ALIGN] = "SP Alignment",
596 [ESR_ELx_EC_FP_EXC32] = "FP (AArch32)",
597 [ESR_ELx_EC_FP_EXC64] = "FP (AArch64)",
598 [ESR_ELx_EC_SERROR] = "SError",
599 [ESR_ELx_EC_BREAKPT_LOW] = "Breakpoint (lower EL)",
600 [ESR_ELx_EC_BREAKPT_CUR] = "Breakpoint (current EL)",
601 [ESR_ELx_EC_SOFTSTP_LOW] = "Software Step (lower EL)",
602 [ESR_ELx_EC_SOFTSTP_CUR] = "Software Step (current EL)",
603 [ESR_ELx_EC_WATCHPT_LOW] = "Watchpoint (lower EL)",
604 [ESR_ELx_EC_WATCHPT_CUR] = "Watchpoint (current EL)",
605 [ESR_ELx_EC_BKPT32] = "BKPT (AArch32)",
606 [ESR_ELx_EC_VECTOR32] = "Vector catch (AArch32)",
607 [ESR_ELx_EC_BRK64] = "BRK (AArch64)",
610 const char *esr_get_class_string(u32 esr)
612 return esr_class_str[ESR_ELx_EC(esr)];
616 * bad_mode handles the impossible case in the exception vector. This is always
619 asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
623 pr_crit("Bad mode in %s handler detected on CPU%d, code 0x%08x -- %s\n",
624 handler[reason], smp_processor_id(), esr,
625 esr_get_class_string(esr));
627 die("Oops - bad mode", regs, 0);
633 * bad_el0_sync handles unexpected, but potentially recoverable synchronous
634 * exceptions taken from EL0. Unlike bad_mode, this returns.
636 asmlinkage void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr)
639 void __user *pc = (void __user *)instruction_pointer(regs);
642 pr_crit("Bad EL0 synchronous exception detected on CPU%d, code 0x%08x -- %s\n",
643 smp_processor_id(), esr, esr_get_class_string(esr));
646 info.si_signo = SIGILL;
648 info.si_code = ILL_ILLOPC;
651 current->thread.fault_address = 0;
652 current->thread.fault_code = 0;
654 force_sig_info(info.si_signo, &info, current);
657 void __pte_error(const char *file, int line, unsigned long val)
659 pr_err("%s:%d: bad pte %016lx.\n", file, line, val);
662 void __pmd_error(const char *file, int line, unsigned long val)
664 pr_err("%s:%d: bad pmd %016lx.\n", file, line, val);
667 void __pud_error(const char *file, int line, unsigned long val)
669 pr_err("%s:%d: bad pud %016lx.\n", file, line, val);
672 void __pgd_error(const char *file, int line, unsigned long val)
674 pr_err("%s:%d: bad pgd %016lx.\n", file, line, val);
677 /* GENERIC_BUG traps */
679 int is_valid_bugaddr(unsigned long addr)
682 * bug_handler() only called for BRK #BUG_BRK_IMM.
683 * So the answer is trivial -- any spurious instances with no
684 * bug table entry will be rejected by report_bug() and passed
685 * back to the debug-monitors code and handled as a fatal
686 * unexpected debug exception.
691 static int bug_handler(struct pt_regs *regs, unsigned int esr)
694 return DBG_HOOK_ERROR;
696 switch (report_bug(regs->pc, regs)) {
697 case BUG_TRAP_TYPE_BUG:
698 die("Oops - BUG", regs, 0);
701 case BUG_TRAP_TYPE_WARN:
702 /* Ideally, report_bug() should backtrace for us... but no. */
703 dump_backtrace(regs, NULL);
707 /* unknown/unrecognised bug trap type */
708 return DBG_HOOK_ERROR;
711 /* If thread survives, skip over the BUG instruction and continue: */
712 regs->pc += AARCH64_INSN_SIZE; /* skip BRK and resume */
713 return DBG_HOOK_HANDLED;
716 static struct break_hook bug_break_hook = {
717 .esr_val = 0xf2000000 | BUG_BRK_IMM,
718 .esr_mask = 0xffffffff,
723 * Initial handler for AArch64 BRK exceptions
724 * This handler only used until debug_traps_init().
726 int __init early_brk64(unsigned long addr, unsigned int esr,
727 struct pt_regs *regs)
729 return bug_handler(regs, esr) != DBG_HOOK_HANDLED;
732 /* This registration must happen early, before debug_traps_init(). */
733 void __init trap_init(void)
735 register_break_hook(&bug_break_hook);