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.
72 printk("%s%s(0x%016lx to 0x%016lx)\n", lvl
, str
, bottom
, top
);
74 for (first
= bottom
& ~31; first
< top
; first
+= 32) {
76 char str
[sizeof(" 12345678") * 8 + 1];
78 memset(str
, ' ', sizeof(str
));
79 str
[sizeof(str
) - 1] = '\0';
81 for (p
= first
, i
= 0; i
< (32 / width
)
82 && p
< top
; i
++, p
+= width
) {
83 if (p
>= bottom
&& p
< top
) {
87 if (__get_user(val
, (unsigned long *)p
) == 0)
88 sprintf(str
+ i
* 17, " %016lx", val
);
90 sprintf(str
+ i
* 17, " ????????????????");
92 if (__get_user(val
, (unsigned int *)p
) == 0)
93 sprintf(str
+ i
* 9, " %08lx", val
);
95 sprintf(str
+ i
* 9, " ????????");
99 printk("%s%04lx:%s\n", lvl
, first
& 0xffff, str
);
105 static void dump_backtrace_entry(unsigned long where
)
108 * Note that 'where' can have a physical address, but it's not handled.
113 static void __dump_instr(const char *lvl
, struct pt_regs
*regs
)
115 unsigned long addr
= instruction_pointer(regs
);
116 char str
[sizeof("00000000 ") * 5 + 2 + 1], *p
= str
;
119 for (i
= -4; i
< 1; i
++) {
120 unsigned int val
, bad
;
122 bad
= __get_user(val
, &((u32
*)addr
)[i
]);
125 p
+= sprintf(p
, i
== 0 ? "(%08x) " : "%08x ", val
);
127 p
+= sprintf(p
, "bad PC value");
131 printk("%sCode: %s\n", lvl
, str
);
134 static void dump_instr(const char *lvl
, struct pt_regs
*regs
)
136 if (!user_mode(regs
)) {
137 mm_segment_t fs
= get_fs();
139 __dump_instr(lvl
, regs
);
142 __dump_instr(lvl
, regs
);
146 static void dump_backtrace(struct pt_regs
*regs
, struct task_struct
*tsk
)
148 struct stackframe frame
;
149 unsigned long irq_stack_ptr
;
153 * Switching between stacks is valid when tracing current and in
154 * non-preemptible context.
156 if (tsk
== current
&& !preemptible())
157 irq_stack_ptr
= IRQ_STACK_PTR(smp_processor_id());
161 pr_debug("%s(regs = %p tsk = %p)\n", __func__
, regs
, tsk
);
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
), false);
224 void show_stack(struct task_struct
*tsk
, unsigned long *sp
)
226 dump_backtrace(NULL
, tsk
);
230 #ifdef CONFIG_PREEMPT
231 #define S_PREEMPT " PREEMPT"
237 static int __die(const char *str
, int err
, struct thread_info
*thread
,
238 struct pt_regs
*regs
)
240 struct task_struct
*tsk
= thread
->task
;
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
), thread
+ 1);
257 if (!user_mode(regs
) || in_interrupt()) {
258 dump_mem(KERN_EMERG
, "Stack: ", regs
->sp
,
259 THREAD_SIZE
+ (unsigned long)task_stack_page(tsk
),
260 compat_user_mode(regs
));
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
)
275 struct thread_info
*thread
= current_thread_info();
280 raw_spin_lock_irq(&die_lock
);
283 ret
= __die(str
, err
, thread
, regs
);
285 if (regs
&& kexec_should_crash(thread
->task
))
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 asmlinkage
void __exception
do_undefinstr(struct pt_regs
*regs
)
379 void __user
*pc
= (void __user
*)instruction_pointer(regs
);
381 /* check for AArch32 breakpoint instructions */
382 if (!aarch32_break_handler(regs
))
385 if (call_undef_hook(regs
) == 0)
388 if (unhandled_signal(current
, SIGILL
) && show_unhandled_signals_ratelimited()) {
389 pr_info("%s[%d]: undefined instruction: pc=%p\n",
390 current
->comm
, task_pid_nr(current
), pc
);
391 dump_instr(KERN_INFO
, regs
);
394 info
.si_signo
= SIGILL
;
396 info
.si_code
= ILL_ILLOPC
;
399 arm64_notify_die("Oops - undefined instruction", regs
, &info
, 0);
402 long compat_arm_syscall(struct pt_regs
*regs
);
404 asmlinkage
long do_ni_syscall(struct pt_regs
*regs
)
408 if (is_compat_task()) {
409 ret
= compat_arm_syscall(regs
);
415 if (show_unhandled_signals_ratelimited()) {
416 pr_info("%s[%d]: syscall %d\n", current
->comm
,
417 task_pid_nr(current
), (int)regs
->syscallno
);
418 dump_instr("", regs
);
423 return sys_ni_syscall();
426 static const char *esr_class_str
[] = {
427 [0 ... ESR_ELx_EC_MAX
] = "UNRECOGNIZED EC",
428 [ESR_ELx_EC_UNKNOWN
] = "Unknown/Uncategorized",
429 [ESR_ELx_EC_WFx
] = "WFI/WFE",
430 [ESR_ELx_EC_CP15_32
] = "CP15 MCR/MRC",
431 [ESR_ELx_EC_CP15_64
] = "CP15 MCRR/MRRC",
432 [ESR_ELx_EC_CP14_MR
] = "CP14 MCR/MRC",
433 [ESR_ELx_EC_CP14_LS
] = "CP14 LDC/STC",
434 [ESR_ELx_EC_FP_ASIMD
] = "ASIMD",
435 [ESR_ELx_EC_CP10_ID
] = "CP10 MRC/VMRS",
436 [ESR_ELx_EC_CP14_64
] = "CP14 MCRR/MRRC",
437 [ESR_ELx_EC_ILL
] = "PSTATE.IL",
438 [ESR_ELx_EC_SVC32
] = "SVC (AArch32)",
439 [ESR_ELx_EC_HVC32
] = "HVC (AArch32)",
440 [ESR_ELx_EC_SMC32
] = "SMC (AArch32)",
441 [ESR_ELx_EC_SVC64
] = "SVC (AArch64)",
442 [ESR_ELx_EC_HVC64
] = "HVC (AArch64)",
443 [ESR_ELx_EC_SMC64
] = "SMC (AArch64)",
444 [ESR_ELx_EC_SYS64
] = "MSR/MRS (AArch64)",
445 [ESR_ELx_EC_IMP_DEF
] = "EL3 IMP DEF",
446 [ESR_ELx_EC_IABT_LOW
] = "IABT (lower EL)",
447 [ESR_ELx_EC_IABT_CUR
] = "IABT (current EL)",
448 [ESR_ELx_EC_PC_ALIGN
] = "PC Alignment",
449 [ESR_ELx_EC_DABT_LOW
] = "DABT (lower EL)",
450 [ESR_ELx_EC_DABT_CUR
] = "DABT (current EL)",
451 [ESR_ELx_EC_SP_ALIGN
] = "SP Alignment",
452 [ESR_ELx_EC_FP_EXC32
] = "FP (AArch32)",
453 [ESR_ELx_EC_FP_EXC64
] = "FP (AArch64)",
454 [ESR_ELx_EC_SERROR
] = "SError",
455 [ESR_ELx_EC_BREAKPT_LOW
] = "Breakpoint (lower EL)",
456 [ESR_ELx_EC_BREAKPT_CUR
] = "Breakpoint (current EL)",
457 [ESR_ELx_EC_SOFTSTP_LOW
] = "Software Step (lower EL)",
458 [ESR_ELx_EC_SOFTSTP_CUR
] = "Software Step (current EL)",
459 [ESR_ELx_EC_WATCHPT_LOW
] = "Watchpoint (lower EL)",
460 [ESR_ELx_EC_WATCHPT_CUR
] = "Watchpoint (current EL)",
461 [ESR_ELx_EC_BKPT32
] = "BKPT (AArch32)",
462 [ESR_ELx_EC_VECTOR32
] = "Vector catch (AArch32)",
463 [ESR_ELx_EC_BRK64
] = "BRK (AArch64)",
466 const char *esr_get_class_string(u32 esr
)
468 return esr_class_str
[esr
>> ESR_ELx_EC_SHIFT
];
472 * bad_mode handles the impossible case in the exception vector.
474 asmlinkage
void bad_mode(struct pt_regs
*regs
, int reason
, unsigned int esr
)
477 void __user
*pc
= (void __user
*)instruction_pointer(regs
);
480 pr_crit("Bad mode in %s handler detected on CPU%d, code 0x%08x -- %s\n",
481 handler
[reason
], smp_processor_id(), esr
,
482 esr_get_class_string(esr
));
485 info
.si_signo
= SIGILL
;
487 info
.si_code
= ILL_ILLOPC
;
490 arm64_notify_die("Oops - bad mode", regs
, &info
, 0);
493 void __pte_error(const char *file
, int line
, unsigned long val
)
495 pr_err("%s:%d: bad pte %016lx.\n", file
, line
, val
);
498 void __pmd_error(const char *file
, int line
, unsigned long val
)
500 pr_err("%s:%d: bad pmd %016lx.\n", file
, line
, val
);
503 void __pud_error(const char *file
, int line
, unsigned long val
)
505 pr_err("%s:%d: bad pud %016lx.\n", file
, line
, val
);
508 void __pgd_error(const char *file
, int line
, unsigned long val
)
510 pr_err("%s:%d: bad pgd %016lx.\n", file
, line
, val
);
513 /* GENERIC_BUG traps */
515 int is_valid_bugaddr(unsigned long addr
)
518 * bug_handler() only called for BRK #BUG_BRK_IMM.
519 * So the answer is trivial -- any spurious instances with no
520 * bug table entry will be rejected by report_bug() and passed
521 * back to the debug-monitors code and handled as a fatal
522 * unexpected debug exception.
527 static int bug_handler(struct pt_regs
*regs
, unsigned int esr
)
530 return DBG_HOOK_ERROR
;
532 switch (report_bug(regs
->pc
, regs
)) {
533 case BUG_TRAP_TYPE_BUG
:
534 die("Oops - BUG", regs
, 0);
537 case BUG_TRAP_TYPE_WARN
:
538 /* Ideally, report_bug() should backtrace for us... but no. */
539 dump_backtrace(regs
, NULL
);
543 /* unknown/unrecognised bug trap type */
544 return DBG_HOOK_ERROR
;
547 /* If thread survives, skip over the BUG instruction and continue: */
548 regs
->pc
+= AARCH64_INSN_SIZE
; /* skip BRK and resume */
549 return DBG_HOOK_HANDLED
;
552 static struct break_hook bug_break_hook
= {
553 .esr_val
= 0xf2000000 | BUG_BRK_IMM
,
554 .esr_mask
= 0xffffffff,
559 * Initial handler for AArch64 BRK exceptions
560 * This handler only used until debug_traps_init().
562 int __init
early_brk64(unsigned long addr
, unsigned int esr
,
563 struct pt_regs
*regs
)
565 return bug_handler(regs
, esr
) != DBG_HOOK_HANDLED
;
568 /* This registration must happen early, before debug_traps_init(). */
569 void __init
trap_init(void)
571 register_break_hook(&bug_break_hook
);