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
);