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.h>
33 #include <linux/syscalls.h>
35 #include <asm/atomic.h>
37 #include <asm/debug-monitors.h>
40 #include <asm/traps.h>
41 #include <asm/stacktrace.h>
42 #include <asm/exception.h>
43 #include <asm/system_misc.h>
45 static const char *handler[]= {
52 int show_unhandled_signals = 1;
55 * Dump out the contents of some memory nicely...
57 static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
58 unsigned long top, bool compat)
63 unsigned int width = compat ? 4 : 8;
66 * We need to switch to kernel mode so that we can use __get_user
67 * to safely read from kernel space. Note that we now dump the
68 * code first, just in case the backtrace kills us.
73 printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top);
75 for (first = bottom & ~31; first < top; first += 32) {
77 char str[sizeof(" 12345678") * 8 + 1];
79 memset(str, ' ', sizeof(str));
80 str[sizeof(str) - 1] = '\0';
82 for (p = first, i = 0; i < (32 / width)
83 && p < top; i++, p += width) {
84 if (p >= bottom && p < top) {
88 if (__get_user(val, (unsigned long *)p) == 0)
89 sprintf(str + i * 17, " %016lx", val);
91 sprintf(str + i * 17, " ????????????????");
93 if (__get_user(val, (unsigned int *)p) == 0)
94 sprintf(str + i * 9, " %08lx", val);
96 sprintf(str + i * 9, " ????????");
100 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
106 static void dump_backtrace_entry(unsigned long where)
109 * Note that 'where' can have a physical address, but it's not handled.
114 static void dump_instr(const char *lvl, struct pt_regs *regs)
116 unsigned long addr = instruction_pointer(regs);
118 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
122 * We need to switch to kernel mode so that we can use __get_user
123 * to safely read from kernel space. Note that we now dump the
124 * code first, just in case the backtrace kills us.
129 for (i = -4; i < 1; i++) {
130 unsigned int val, bad;
132 bad = __get_user(val, &((u32 *)addr)[i]);
135 p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
137 p += sprintf(p, "bad PC value");
141 printk("%sCode: %s\n", lvl, str);
146 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
148 struct stackframe frame;
149 unsigned long irq_stack_ptr = IRQ_STACK_PTR(smp_processor_id());
151 pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
157 frame.fp = regs->regs[29];
160 } else if (tsk == current) {
161 frame.fp = (unsigned long)__builtin_frame_address(0);
162 frame.sp = current_stack_pointer;
163 frame.pc = (unsigned long)dump_backtrace;
166 * task blocked in __switch_to
168 frame.fp = thread_saved_fp(tsk);
169 frame.sp = thread_saved_sp(tsk);
170 frame.pc = thread_saved_pc(tsk);
173 pr_emerg("Call trace:\n");
175 unsigned long where = frame.pc;
179 dump_backtrace_entry(where);
180 ret = unwind_frame(&frame);
184 if (in_exception_text(where)) {
186 * If we switched to the irq_stack before calling this
187 * exception handler, then the pt_regs will be on the
188 * task stack. The easiest way to tell is if the large
189 * pt_regs would overlap with the end of the irq_stack.
191 if (stack < irq_stack_ptr &&
192 (stack + sizeof(struct pt_regs)) > irq_stack_ptr)
193 stack = IRQ_STACK_TO_TASK_STACK(irq_stack_ptr);
195 dump_mem("", "Exception stack", stack,
196 stack + sizeof(struct pt_regs), false);
201 void show_stack(struct task_struct *tsk, unsigned long *sp)
203 dump_backtrace(NULL, tsk);
207 #ifdef CONFIG_PREEMPT
208 #define S_PREEMPT " PREEMPT"
214 static int __die(const char *str, int err, struct thread_info *thread,
215 struct pt_regs *regs)
217 struct task_struct *tsk = thread->task;
218 static int die_counter;
221 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
222 str, err, ++die_counter);
224 /* trap and error numbers are mostly meaningless on ARM */
225 ret = notify_die(DIE_OOPS, str, regs, err, 0, SIGSEGV);
226 if (ret == NOTIFY_STOP)
231 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
232 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1);
234 if (!user_mode(regs) || in_interrupt()) {
235 dump_mem(KERN_EMERG, "Stack: ", regs->sp,
236 THREAD_SIZE + (unsigned long)task_stack_page(tsk),
237 compat_user_mode(regs));
238 dump_backtrace(regs, tsk);
239 dump_instr(KERN_EMERG, regs);
245 static DEFINE_RAW_SPINLOCK(die_lock);
248 * This function is protected against re-entrancy.
250 void die(const char *str, struct pt_regs *regs, int err)
252 struct thread_info *thread = current_thread_info();
257 raw_spin_lock_irq(&die_lock);
260 ret = __die(str, err, thread, regs);
262 if (regs && kexec_should_crash(thread->task))
266 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
267 raw_spin_unlock_irq(&die_lock);
271 panic("Fatal exception in interrupt");
273 panic("Fatal exception");
274 if (ret != NOTIFY_STOP)
278 void arm64_notify_die(const char *str, struct pt_regs *regs,
279 struct siginfo *info, int err)
281 if (user_mode(regs)) {
282 current->thread.fault_address = 0;
283 current->thread.fault_code = err;
284 force_sig_info(info->si_signo, info, current);
290 static LIST_HEAD(undef_hook);
291 static DEFINE_RAW_SPINLOCK(undef_lock);
293 void register_undef_hook(struct undef_hook *hook)
297 raw_spin_lock_irqsave(&undef_lock, flags);
298 list_add(&hook->node, &undef_hook);
299 raw_spin_unlock_irqrestore(&undef_lock, flags);
302 void unregister_undef_hook(struct undef_hook *hook)
306 raw_spin_lock_irqsave(&undef_lock, flags);
307 list_del(&hook->node);
308 raw_spin_unlock_irqrestore(&undef_lock, flags);
311 static int call_undef_hook(struct pt_regs *regs)
313 struct undef_hook *hook;
316 int (*fn)(struct pt_regs *regs, u32 instr) = NULL;
317 void __user *pc = (void __user *)instruction_pointer(regs);
319 if (!user_mode(regs))
322 if (compat_thumb_mode(regs)) {
323 /* 16-bit Thumb instruction */
324 if (get_user(instr, (u16 __user *)pc))
326 instr = le16_to_cpu(instr);
327 if (aarch32_insn_is_wide(instr)) {
330 if (get_user(instr2, (u16 __user *)(pc + 2)))
332 instr2 = le16_to_cpu(instr2);
333 instr = (instr << 16) | instr2;
336 /* 32-bit ARM instruction */
337 if (get_user(instr, (u32 __user *)pc))
339 instr = le32_to_cpu(instr);
342 raw_spin_lock_irqsave(&undef_lock, flags);
343 list_for_each_entry(hook, &undef_hook, node)
344 if ((instr & hook->instr_mask) == hook->instr_val &&
345 (regs->pstate & hook->pstate_mask) == hook->pstate_val)
348 raw_spin_unlock_irqrestore(&undef_lock, flags);
350 return fn ? fn(regs, instr) : 1;
353 asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
356 void __user *pc = (void __user *)instruction_pointer(regs);
358 /* check for AArch32 breakpoint instructions */
359 if (!aarch32_break_handler(regs))
362 if (call_undef_hook(regs) == 0)
365 if (unhandled_signal(current, SIGILL) && show_unhandled_signals_ratelimited()) {
366 pr_info("%s[%d]: undefined instruction: pc=%p\n",
367 current->comm, task_pid_nr(current), pc);
368 dump_instr(KERN_INFO, regs);
371 info.si_signo = SIGILL;
373 info.si_code = ILL_ILLOPC;
376 arm64_notify_die("Oops - undefined instruction", regs, &info, 0);
379 long compat_arm_syscall(struct pt_regs *regs);
381 asmlinkage long do_ni_syscall(struct pt_regs *regs)
385 if (is_compat_task()) {
386 ret = compat_arm_syscall(regs);
392 if (show_unhandled_signals_ratelimited()) {
393 pr_info("%s[%d]: syscall %d\n", current->comm,
394 task_pid_nr(current), (int)regs->syscallno);
395 dump_instr("", regs);
400 return sys_ni_syscall();
403 static const char *esr_class_str[] = {
404 [0 ... ESR_ELx_EC_MAX] = "UNRECOGNIZED EC",
405 [ESR_ELx_EC_UNKNOWN] = "Unknown/Uncategorized",
406 [ESR_ELx_EC_WFx] = "WFI/WFE",
407 [ESR_ELx_EC_CP15_32] = "CP15 MCR/MRC",
408 [ESR_ELx_EC_CP15_64] = "CP15 MCRR/MRRC",
409 [ESR_ELx_EC_CP14_MR] = "CP14 MCR/MRC",
410 [ESR_ELx_EC_CP14_LS] = "CP14 LDC/STC",
411 [ESR_ELx_EC_FP_ASIMD] = "ASIMD",
412 [ESR_ELx_EC_CP10_ID] = "CP10 MRC/VMRS",
413 [ESR_ELx_EC_CP14_64] = "CP14 MCRR/MRRC",
414 [ESR_ELx_EC_ILL] = "PSTATE.IL",
415 [ESR_ELx_EC_SVC32] = "SVC (AArch32)",
416 [ESR_ELx_EC_HVC32] = "HVC (AArch32)",
417 [ESR_ELx_EC_SMC32] = "SMC (AArch32)",
418 [ESR_ELx_EC_SVC64] = "SVC (AArch64)",
419 [ESR_ELx_EC_HVC64] = "HVC (AArch64)",
420 [ESR_ELx_EC_SMC64] = "SMC (AArch64)",
421 [ESR_ELx_EC_SYS64] = "MSR/MRS (AArch64)",
422 [ESR_ELx_EC_IMP_DEF] = "EL3 IMP DEF",
423 [ESR_ELx_EC_IABT_LOW] = "IABT (lower EL)",
424 [ESR_ELx_EC_IABT_CUR] = "IABT (current EL)",
425 [ESR_ELx_EC_PC_ALIGN] = "PC Alignment",
426 [ESR_ELx_EC_DABT_LOW] = "DABT (lower EL)",
427 [ESR_ELx_EC_DABT_CUR] = "DABT (current EL)",
428 [ESR_ELx_EC_SP_ALIGN] = "SP Alignment",
429 [ESR_ELx_EC_FP_EXC32] = "FP (AArch32)",
430 [ESR_ELx_EC_FP_EXC64] = "FP (AArch64)",
431 [ESR_ELx_EC_SERROR] = "SError",
432 [ESR_ELx_EC_BREAKPT_LOW] = "Breakpoint (lower EL)",
433 [ESR_ELx_EC_BREAKPT_CUR] = "Breakpoint (current EL)",
434 [ESR_ELx_EC_SOFTSTP_LOW] = "Software Step (lower EL)",
435 [ESR_ELx_EC_SOFTSTP_CUR] = "Software Step (current EL)",
436 [ESR_ELx_EC_WATCHPT_LOW] = "Watchpoint (lower EL)",
437 [ESR_ELx_EC_WATCHPT_CUR] = "Watchpoint (current EL)",
438 [ESR_ELx_EC_BKPT32] = "BKPT (AArch32)",
439 [ESR_ELx_EC_VECTOR32] = "Vector catch (AArch32)",
440 [ESR_ELx_EC_BRK64] = "BRK (AArch64)",
443 const char *esr_get_class_string(u32 esr)
445 return esr_class_str[esr >> ESR_ELx_EC_SHIFT];
449 * bad_mode handles the impossible case in the exception vector.
451 asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
454 void __user *pc = (void __user *)instruction_pointer(regs);
457 pr_crit("Bad mode in %s handler detected, code 0x%08x -- %s\n",
458 handler[reason], esr, esr_get_class_string(esr));
461 info.si_signo = SIGILL;
463 info.si_code = ILL_ILLOPC;
466 arm64_notify_die("Oops - bad mode", regs, &info, 0);
469 void __pte_error(const char *file, int line, unsigned long val)
471 pr_crit("%s:%d: bad pte %016lx.\n", file, line, val);
474 void __pmd_error(const char *file, int line, unsigned long val)
476 pr_crit("%s:%d: bad pmd %016lx.\n", file, line, val);
479 void __pud_error(const char *file, int line, unsigned long val)
481 pr_crit("%s:%d: bad pud %016lx.\n", file, line, val);
484 void __pgd_error(const char *file, int line, unsigned long val)
486 pr_crit("%s:%d: bad pgd %016lx.\n", file, line, val);
489 /* GENERIC_BUG traps */
491 int is_valid_bugaddr(unsigned long addr)
494 * bug_handler() only called for BRK #BUG_BRK_IMM.
495 * So the answer is trivial -- any spurious instances with no
496 * bug table entry will be rejected by report_bug() and passed
497 * back to the debug-monitors code and handled as a fatal
498 * unexpected debug exception.
503 static int bug_handler(struct pt_regs *regs, unsigned int esr)
506 return DBG_HOOK_ERROR;
508 switch (report_bug(regs->pc, regs)) {
509 case BUG_TRAP_TYPE_BUG:
510 die("Oops - BUG", regs, 0);
513 case BUG_TRAP_TYPE_WARN:
514 /* Ideally, report_bug() should backtrace for us... but no. */
515 dump_backtrace(regs, NULL);
519 /* unknown/unrecognised bug trap type */
520 return DBG_HOOK_ERROR;
523 /* If thread survives, skip over the BUG instruction and continue: */
524 regs->pc += AARCH64_INSN_SIZE; /* skip BRK and resume */
525 return DBG_HOOK_HANDLED;
528 static struct break_hook bug_break_hook = {
529 .esr_val = 0xf2000000 | BUG_BRK_IMM,
530 .esr_mask = 0xffffffff,
535 * Initial handler for AArch64 BRK exceptions
536 * This handler only used until debug_traps_init().
538 int __init early_brk64(unsigned long addr, unsigned int esr,
539 struct pt_regs *regs)
541 return bug_handler(regs, esr) != DBG_HOOK_HANDLED;
544 /* This registration must happen early, before debug_traps_init(). */
545 void __init trap_init(void)
547 register_break_hook(&bug_break_hook);