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());
152 pr_debug("%s(regs = %p tsk = %p)\n", __func__
, regs
, tsk
);
157 if (tsk
== current
) {
158 frame
.fp
= (unsigned long)__builtin_frame_address(0);
159 frame
.sp
= current_stack_pointer
;
160 frame
.pc
= (unsigned long)dump_backtrace
;
163 * task blocked in __switch_to
165 frame
.fp
= thread_saved_fp(tsk
);
166 frame
.sp
= thread_saved_sp(tsk
);
167 frame
.pc
= thread_saved_pc(tsk
);
169 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
170 frame
.graph
= tsk
->curr_ret_stack
;
174 printk("Call trace:\n");
176 unsigned long where
= frame
.pc
;
180 /* skip until specified stack frame */
182 dump_backtrace_entry(where
);
183 } else if (frame
.fp
== regs
->regs
[29]) {
186 * Mostly, this is the case where this function is
187 * called in panic/abort. As exception handler's
188 * stack frame does not contain the corresponding pc
189 * at which an exception has taken place, use regs->pc
192 dump_backtrace_entry(regs
->pc
);
194 ret
= unwind_frame(tsk
, &frame
);
198 if (in_exception_text(where
)) {
200 * If we switched to the irq_stack before calling this
201 * exception handler, then the pt_regs will be on the
202 * task stack. The easiest way to tell is if the large
203 * pt_regs would overlap with the end of the irq_stack.
205 if (stack
< irq_stack_ptr
&&
206 (stack
+ sizeof(struct pt_regs
)) > irq_stack_ptr
)
207 stack
= IRQ_STACK_TO_TASK_STACK(irq_stack_ptr
);
209 dump_mem("", "Exception stack", stack
,
210 stack
+ sizeof(struct pt_regs
), false);
215 void show_stack(struct task_struct
*tsk
, unsigned long *sp
)
217 dump_backtrace(NULL
, tsk
);
221 #ifdef CONFIG_PREEMPT
222 #define S_PREEMPT " PREEMPT"
228 static int __die(const char *str
, int err
, struct thread_info
*thread
,
229 struct pt_regs
*regs
)
231 struct task_struct
*tsk
= thread
->task
;
232 static int die_counter
;
235 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP
"\n",
236 str
, err
, ++die_counter
);
238 /* trap and error numbers are mostly meaningless on ARM */
239 ret
= notify_die(DIE_OOPS
, str
, regs
, err
, 0, SIGSEGV
);
240 if (ret
== NOTIFY_STOP
)
245 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
246 TASK_COMM_LEN
, tsk
->comm
, task_pid_nr(tsk
), thread
+ 1);
248 if (!user_mode(regs
) || in_interrupt()) {
249 dump_mem(KERN_EMERG
, "Stack: ", regs
->sp
,
250 THREAD_SIZE
+ (unsigned long)task_stack_page(tsk
),
251 compat_user_mode(regs
));
252 dump_backtrace(regs
, tsk
);
253 dump_instr(KERN_EMERG
, regs
);
259 static DEFINE_RAW_SPINLOCK(die_lock
);
262 * This function is protected against re-entrancy.
264 void die(const char *str
, struct pt_regs
*regs
, int err
)
266 struct thread_info
*thread
= current_thread_info();
271 raw_spin_lock_irq(&die_lock
);
274 ret
= __die(str
, err
, thread
, regs
);
276 if (regs
&& kexec_should_crash(thread
->task
))
280 add_taint(TAINT_DIE
, LOCKDEP_NOW_UNRELIABLE
);
281 raw_spin_unlock_irq(&die_lock
);
285 panic("Fatal exception in interrupt");
287 panic("Fatal exception");
288 if (ret
!= NOTIFY_STOP
)
292 void arm64_notify_die(const char *str
, struct pt_regs
*regs
,
293 struct siginfo
*info
, int err
)
295 if (user_mode(regs
)) {
296 current
->thread
.fault_address
= 0;
297 current
->thread
.fault_code
= err
;
298 force_sig_info(info
->si_signo
, info
, current
);
304 static LIST_HEAD(undef_hook
);
305 static DEFINE_RAW_SPINLOCK(undef_lock
);
307 void register_undef_hook(struct undef_hook
*hook
)
311 raw_spin_lock_irqsave(&undef_lock
, flags
);
312 list_add(&hook
->node
, &undef_hook
);
313 raw_spin_unlock_irqrestore(&undef_lock
, flags
);
316 void unregister_undef_hook(struct undef_hook
*hook
)
320 raw_spin_lock_irqsave(&undef_lock
, flags
);
321 list_del(&hook
->node
);
322 raw_spin_unlock_irqrestore(&undef_lock
, flags
);
325 static int call_undef_hook(struct pt_regs
*regs
)
327 struct undef_hook
*hook
;
330 int (*fn
)(struct pt_regs
*regs
, u32 instr
) = NULL
;
331 void __user
*pc
= (void __user
*)instruction_pointer(regs
);
333 if (!user_mode(regs
))
336 if (compat_thumb_mode(regs
)) {
337 /* 16-bit Thumb instruction */
338 if (get_user(instr
, (u16 __user
*)pc
))
340 instr
= le16_to_cpu(instr
);
341 if (aarch32_insn_is_wide(instr
)) {
344 if (get_user(instr2
, (u16 __user
*)(pc
+ 2)))
346 instr2
= le16_to_cpu(instr2
);
347 instr
= (instr
<< 16) | instr2
;
350 /* 32-bit ARM instruction */
351 if (get_user(instr
, (u32 __user
*)pc
))
353 instr
= le32_to_cpu(instr
);
356 raw_spin_lock_irqsave(&undef_lock
, flags
);
357 list_for_each_entry(hook
, &undef_hook
, node
)
358 if ((instr
& hook
->instr_mask
) == hook
->instr_val
&&
359 (regs
->pstate
& hook
->pstate_mask
) == hook
->pstate_val
)
362 raw_spin_unlock_irqrestore(&undef_lock
, flags
);
364 return fn
? fn(regs
, instr
) : 1;
367 asmlinkage
void __exception
do_undefinstr(struct pt_regs
*regs
)
370 void __user
*pc
= (void __user
*)instruction_pointer(regs
);
372 /* check for AArch32 breakpoint instructions */
373 if (!aarch32_break_handler(regs
))
376 if (call_undef_hook(regs
) == 0)
379 if (unhandled_signal(current
, SIGILL
) && show_unhandled_signals_ratelimited()) {
380 pr_info("%s[%d]: undefined instruction: pc=%p\n",
381 current
->comm
, task_pid_nr(current
), pc
);
382 dump_instr(KERN_INFO
, regs
);
385 info
.si_signo
= SIGILL
;
387 info
.si_code
= ILL_ILLOPC
;
390 arm64_notify_die("Oops - undefined instruction", regs
, &info
, 0);
393 long compat_arm_syscall(struct pt_regs
*regs
);
395 asmlinkage
long do_ni_syscall(struct pt_regs
*regs
)
399 if (is_compat_task()) {
400 ret
= compat_arm_syscall(regs
);
406 if (show_unhandled_signals_ratelimited()) {
407 pr_info("%s[%d]: syscall %d\n", current
->comm
,
408 task_pid_nr(current
), (int)regs
->syscallno
);
409 dump_instr("", regs
);
414 return sys_ni_syscall();
417 static const char *esr_class_str
[] = {
418 [0 ... ESR_ELx_EC_MAX
] = "UNRECOGNIZED EC",
419 [ESR_ELx_EC_UNKNOWN
] = "Unknown/Uncategorized",
420 [ESR_ELx_EC_WFx
] = "WFI/WFE",
421 [ESR_ELx_EC_CP15_32
] = "CP15 MCR/MRC",
422 [ESR_ELx_EC_CP15_64
] = "CP15 MCRR/MRRC",
423 [ESR_ELx_EC_CP14_MR
] = "CP14 MCR/MRC",
424 [ESR_ELx_EC_CP14_LS
] = "CP14 LDC/STC",
425 [ESR_ELx_EC_FP_ASIMD
] = "ASIMD",
426 [ESR_ELx_EC_CP10_ID
] = "CP10 MRC/VMRS",
427 [ESR_ELx_EC_CP14_64
] = "CP14 MCRR/MRRC",
428 [ESR_ELx_EC_ILL
] = "PSTATE.IL",
429 [ESR_ELx_EC_SVC32
] = "SVC (AArch32)",
430 [ESR_ELx_EC_HVC32
] = "HVC (AArch32)",
431 [ESR_ELx_EC_SMC32
] = "SMC (AArch32)",
432 [ESR_ELx_EC_SVC64
] = "SVC (AArch64)",
433 [ESR_ELx_EC_HVC64
] = "HVC (AArch64)",
434 [ESR_ELx_EC_SMC64
] = "SMC (AArch64)",
435 [ESR_ELx_EC_SYS64
] = "MSR/MRS (AArch64)",
436 [ESR_ELx_EC_IMP_DEF
] = "EL3 IMP DEF",
437 [ESR_ELx_EC_IABT_LOW
] = "IABT (lower EL)",
438 [ESR_ELx_EC_IABT_CUR
] = "IABT (current EL)",
439 [ESR_ELx_EC_PC_ALIGN
] = "PC Alignment",
440 [ESR_ELx_EC_DABT_LOW
] = "DABT (lower EL)",
441 [ESR_ELx_EC_DABT_CUR
] = "DABT (current EL)",
442 [ESR_ELx_EC_SP_ALIGN
] = "SP Alignment",
443 [ESR_ELx_EC_FP_EXC32
] = "FP (AArch32)",
444 [ESR_ELx_EC_FP_EXC64
] = "FP (AArch64)",
445 [ESR_ELx_EC_SERROR
] = "SError",
446 [ESR_ELx_EC_BREAKPT_LOW
] = "Breakpoint (lower EL)",
447 [ESR_ELx_EC_BREAKPT_CUR
] = "Breakpoint (current EL)",
448 [ESR_ELx_EC_SOFTSTP_LOW
] = "Software Step (lower EL)",
449 [ESR_ELx_EC_SOFTSTP_CUR
] = "Software Step (current EL)",
450 [ESR_ELx_EC_WATCHPT_LOW
] = "Watchpoint (lower EL)",
451 [ESR_ELx_EC_WATCHPT_CUR
] = "Watchpoint (current EL)",
452 [ESR_ELx_EC_BKPT32
] = "BKPT (AArch32)",
453 [ESR_ELx_EC_VECTOR32
] = "Vector catch (AArch32)",
454 [ESR_ELx_EC_BRK64
] = "BRK (AArch64)",
457 const char *esr_get_class_string(u32 esr
)
459 return esr_class_str
[esr
>> ESR_ELx_EC_SHIFT
];
463 * bad_mode handles the impossible case in the exception vector.
465 asmlinkage
void bad_mode(struct pt_regs
*regs
, int reason
, unsigned int esr
)
468 void __user
*pc
= (void __user
*)instruction_pointer(regs
);
471 pr_crit("Bad mode in %s handler detected, code 0x%08x -- %s\n",
472 handler
[reason
], esr
, esr_get_class_string(esr
));
475 info
.si_signo
= SIGILL
;
477 info
.si_code
= ILL_ILLOPC
;
480 arm64_notify_die("Oops - bad mode", regs
, &info
, 0);
483 void __pte_error(const char *file
, int line
, unsigned long val
)
485 pr_err("%s:%d: bad pte %016lx.\n", file
, line
, val
);
488 void __pmd_error(const char *file
, int line
, unsigned long val
)
490 pr_err("%s:%d: bad pmd %016lx.\n", file
, line
, val
);
493 void __pud_error(const char *file
, int line
, unsigned long val
)
495 pr_err("%s:%d: bad pud %016lx.\n", file
, line
, val
);
498 void __pgd_error(const char *file
, int line
, unsigned long val
)
500 pr_err("%s:%d: bad pgd %016lx.\n", file
, line
, val
);
503 /* GENERIC_BUG traps */
505 int is_valid_bugaddr(unsigned long addr
)
508 * bug_handler() only called for BRK #BUG_BRK_IMM.
509 * So the answer is trivial -- any spurious instances with no
510 * bug table entry will be rejected by report_bug() and passed
511 * back to the debug-monitors code and handled as a fatal
512 * unexpected debug exception.
517 static int bug_handler(struct pt_regs
*regs
, unsigned int esr
)
520 return DBG_HOOK_ERROR
;
522 switch (report_bug(regs
->pc
, regs
)) {
523 case BUG_TRAP_TYPE_BUG
:
524 die("Oops - BUG", regs
, 0);
527 case BUG_TRAP_TYPE_WARN
:
528 /* Ideally, report_bug() should backtrace for us... but no. */
529 dump_backtrace(regs
, NULL
);
533 /* unknown/unrecognised bug trap type */
534 return DBG_HOOK_ERROR
;
537 /* If thread survives, skip over the BUG instruction and continue: */
538 regs
->pc
+= AARCH64_INSN_SIZE
; /* skip BRK and resume */
539 return DBG_HOOK_HANDLED
;
542 static struct break_hook bug_break_hook
= {
543 .esr_val
= 0xf2000000 | BUG_BRK_IMM
,
544 .esr_mask
= 0xffffffff,
549 * Initial handler for AArch64 BRK exceptions
550 * This handler only used until debug_traps_init().
552 int __init
early_brk64(unsigned long addr
, unsigned int esr
,
553 struct pt_regs
*regs
)
555 return bug_handler(regs
, esr
) != DBG_HOOK_HANDLED
;
558 /* This registration must happen early, before debug_traps_init(). */
559 void __init
trap_init(void)
561 register_break_hook(&bug_break_hook
);