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>
44 #include <asm/sysreg.h>
46 static const char *handler
[]= {
53 int show_unhandled_signals
= 1;
56 * Dump out the contents of some kernel memory nicely...
58 static void dump_mem(const char *lvl
, const char *str
, unsigned long bottom
,
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 / 8)
82 && p
< top
; i
++, p
+= 8) {
83 if (p
>= bottom
&& p
< top
) {
86 if (__get_user(val
, (unsigned long *)p
) == 0)
87 sprintf(str
+ i
* 17, " %016lx", val
);
89 sprintf(str
+ i
* 17, " ????????????????");
92 printk("%s%04lx:%s\n", lvl
, first
& 0xffff, str
);
98 static void dump_backtrace_entry(unsigned long where
)
101 * Note that 'where' can have a physical address, but it's not handled.
106 static void __dump_instr(const char *lvl
, struct pt_regs
*regs
)
108 unsigned long addr
= instruction_pointer(regs
);
109 char str
[sizeof("00000000 ") * 5 + 2 + 1], *p
= str
;
112 for (i
= -4; i
< 1; i
++) {
113 unsigned int val
, bad
;
115 bad
= __get_user(val
, &((u32
*)addr
)[i
]);
118 p
+= sprintf(p
, i
== 0 ? "(%08x) " : "%08x ", val
);
120 p
+= sprintf(p
, "bad PC value");
124 printk("%sCode: %s\n", lvl
, str
);
127 static void dump_instr(const char *lvl
, struct pt_regs
*regs
)
129 if (!user_mode(regs
)) {
130 mm_segment_t fs
= get_fs();
132 __dump_instr(lvl
, regs
);
135 __dump_instr(lvl
, regs
);
139 static void dump_backtrace(struct pt_regs
*regs
, struct task_struct
*tsk
)
141 struct stackframe frame
;
142 unsigned long irq_stack_ptr
;
145 pr_debug("%s(regs = %p tsk = %p)\n", __func__
, regs
, tsk
);
151 * Switching between stacks is valid when tracing current and in
152 * non-preemptible context.
154 if (tsk
== current
&& !preemptible())
155 irq_stack_ptr
= IRQ_STACK_PTR(smp_processor_id());
159 if (tsk
== current
) {
160 frame
.fp
= (unsigned long)__builtin_frame_address(0);
161 frame
.sp
= current_stack_pointer
;
162 frame
.pc
= (unsigned long)dump_backtrace
;
165 * task blocked in __switch_to
167 frame
.fp
= thread_saved_fp(tsk
);
168 frame
.sp
= thread_saved_sp(tsk
);
169 frame
.pc
= thread_saved_pc(tsk
);
171 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
172 frame
.graph
= tsk
->curr_ret_stack
;
176 printk("Call trace:\n");
178 unsigned long where
= frame
.pc
;
182 /* skip until specified stack frame */
184 dump_backtrace_entry(where
);
185 } else if (frame
.fp
== regs
->regs
[29]) {
188 * Mostly, this is the case where this function is
189 * called in panic/abort. As exception handler's
190 * stack frame does not contain the corresponding pc
191 * at which an exception has taken place, use regs->pc
194 dump_backtrace_entry(regs
->pc
);
196 ret
= unwind_frame(tsk
, &frame
);
200 if (in_exception_text(where
)) {
202 * If we switched to the irq_stack before calling this
203 * exception handler, then the pt_regs will be on the
204 * task stack. The easiest way to tell is if the large
205 * pt_regs would overlap with the end of the irq_stack.
207 if (stack
< irq_stack_ptr
&&
208 (stack
+ sizeof(struct pt_regs
)) > irq_stack_ptr
)
209 stack
= IRQ_STACK_TO_TASK_STACK(irq_stack_ptr
);
211 dump_mem("", "Exception stack", stack
,
212 stack
+ sizeof(struct pt_regs
));
217 void show_stack(struct task_struct
*tsk
, unsigned long *sp
)
219 dump_backtrace(NULL
, tsk
);
223 #ifdef CONFIG_PREEMPT
224 #define S_PREEMPT " PREEMPT"
230 static int __die(const char *str
, int err
, struct thread_info
*thread
,
231 struct pt_regs
*regs
)
233 struct task_struct
*tsk
= thread
->task
;
234 static int die_counter
;
237 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP
"\n",
238 str
, err
, ++die_counter
);
240 /* trap and error numbers are mostly meaningless on ARM */
241 ret
= notify_die(DIE_OOPS
, str
, regs
, err
, 0, SIGSEGV
);
242 if (ret
== NOTIFY_STOP
)
247 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
248 TASK_COMM_LEN
, tsk
->comm
, task_pid_nr(tsk
), thread
+ 1);
250 if (!user_mode(regs
)) {
251 dump_mem(KERN_EMERG
, "Stack: ", regs
->sp
,
252 THREAD_SIZE
+ (unsigned long)task_stack_page(tsk
));
253 dump_backtrace(regs
, tsk
);
254 dump_instr(KERN_EMERG
, regs
);
260 static DEFINE_RAW_SPINLOCK(die_lock
);
263 * This function is protected against re-entrancy.
265 void die(const char *str
, struct pt_regs
*regs
, int err
)
267 struct thread_info
*thread
= current_thread_info();
272 raw_spin_lock_irq(&die_lock
);
275 ret
= __die(str
, err
, thread
, regs
);
277 if (regs
&& kexec_should_crash(thread
->task
))
281 add_taint(TAINT_DIE
, LOCKDEP_NOW_UNRELIABLE
);
282 raw_spin_unlock_irq(&die_lock
);
286 panic("Fatal exception in interrupt");
288 panic("Fatal exception");
289 if (ret
!= NOTIFY_STOP
)
293 void arm64_notify_die(const char *str
, struct pt_regs
*regs
,
294 struct siginfo
*info
, int err
)
296 if (user_mode(regs
)) {
297 current
->thread
.fault_address
= 0;
298 current
->thread
.fault_code
= err
;
299 force_sig_info(info
->si_signo
, info
, current
);
305 static LIST_HEAD(undef_hook
);
306 static DEFINE_RAW_SPINLOCK(undef_lock
);
308 void register_undef_hook(struct undef_hook
*hook
)
312 raw_spin_lock_irqsave(&undef_lock
, flags
);
313 list_add(&hook
->node
, &undef_hook
);
314 raw_spin_unlock_irqrestore(&undef_lock
, flags
);
317 void unregister_undef_hook(struct undef_hook
*hook
)
321 raw_spin_lock_irqsave(&undef_lock
, flags
);
322 list_del(&hook
->node
);
323 raw_spin_unlock_irqrestore(&undef_lock
, flags
);
326 static int call_undef_hook(struct pt_regs
*regs
)
328 struct undef_hook
*hook
;
331 int (*fn
)(struct pt_regs
*regs
, u32 instr
) = NULL
;
332 void __user
*pc
= (void __user
*)instruction_pointer(regs
);
334 if (!user_mode(regs
))
337 if (compat_thumb_mode(regs
)) {
338 /* 16-bit Thumb instruction */
339 if (get_user(instr
, (u16 __user
*)pc
))
341 instr
= le16_to_cpu(instr
);
342 if (aarch32_insn_is_wide(instr
)) {
345 if (get_user(instr2
, (u16 __user
*)(pc
+ 2)))
347 instr2
= le16_to_cpu(instr2
);
348 instr
= (instr
<< 16) | instr2
;
351 /* 32-bit ARM instruction */
352 if (get_user(instr
, (u32 __user
*)pc
))
354 instr
= le32_to_cpu(instr
);
357 raw_spin_lock_irqsave(&undef_lock
, flags
);
358 list_for_each_entry(hook
, &undef_hook
, node
)
359 if ((instr
& hook
->instr_mask
) == hook
->instr_val
&&
360 (regs
->pstate
& hook
->pstate_mask
) == hook
->pstate_val
)
363 raw_spin_unlock_irqrestore(&undef_lock
, flags
);
365 return fn
? fn(regs
, instr
) : 1;
368 static void force_signal_inject(int signal
, int code
, struct pt_regs
*regs
,
369 unsigned long address
)
372 void __user
*pc
= (void __user
*)instruction_pointer(regs
);
377 desc
= "undefined instruction";
380 desc
= "illegal memory access";
387 if (unhandled_signal(current
, signal
) &&
388 show_unhandled_signals_ratelimited()) {
389 pr_info("%s[%d]: %s: pc=%p\n",
390 current
->comm
, task_pid_nr(current
), desc
, pc
);
391 dump_instr(KERN_INFO
, regs
);
394 info
.si_signo
= signal
;
399 arm64_notify_die(desc
, regs
, &info
, 0);
403 * Set up process info to signal segmentation fault - called on access error.
405 void arm64_notify_segfault(struct pt_regs
*regs
, unsigned long addr
)
409 down_read(¤t
->mm
->mmap_sem
);
410 if (find_vma(current
->mm
, addr
) == NULL
)
414 up_read(¤t
->mm
->mmap_sem
);
416 force_signal_inject(SIGSEGV
, code
, regs
, addr
);
419 asmlinkage
void __exception
do_undefinstr(struct pt_regs
*regs
)
421 /* check for AArch32 breakpoint instructions */
422 if (!aarch32_break_handler(regs
))
425 if (call_undef_hook(regs
) == 0)
428 force_signal_inject(SIGILL
, ILL_ILLOPC
, regs
, 0);
431 void cpu_enable_cache_maint_trap(void *__unused
)
433 config_sctlr_el1(SCTLR_EL1_UCI
, 0);
436 #define __user_cache_maint(insn, address, res) \
438 "1: " insn ", %1\n" \
441 " .pushsection .fixup,\"ax\"\n" \
443 "3: mov %w0, %w2\n" \
446 _ASM_EXTABLE(1b, 3b) \
448 : "r" (address), "i" (-EFAULT) )
450 static void user_cache_maint_handler(unsigned int esr
, struct pt_regs
*regs
)
452 unsigned long address
;
453 int rt
= (esr
& ESR_ELx_SYS64_ISS_RT_MASK
) >> ESR_ELx_SYS64_ISS_RT_SHIFT
;
454 int crm
= (esr
& ESR_ELx_SYS64_ISS_CRM_MASK
) >> ESR_ELx_SYS64_ISS_CRM_SHIFT
;
457 address
= (rt
== 31) ? 0 : regs
->regs
[rt
];
460 case ESR_ELx_SYS64_ISS_CRM_DC_CVAU
: /* DC CVAU, gets promoted */
461 __user_cache_maint("dc civac", address
, ret
);
463 case ESR_ELx_SYS64_ISS_CRM_DC_CVAC
: /* DC CVAC, gets promoted */
464 __user_cache_maint("dc civac", address
, ret
);
466 case ESR_ELx_SYS64_ISS_CRM_DC_CIVAC
: /* DC CIVAC */
467 __user_cache_maint("dc civac", address
, ret
);
469 case ESR_ELx_SYS64_ISS_CRM_IC_IVAU
: /* IC IVAU */
470 __user_cache_maint("ic ivau", address
, ret
);
473 force_signal_inject(SIGILL
, ILL_ILLOPC
, regs
, 0);
478 arm64_notify_segfault(regs
, address
);
483 static void ctr_read_handler(unsigned int esr
, struct pt_regs
*regs
)
485 int rt
= (esr
& ESR_ELx_SYS64_ISS_RT_MASK
) >> ESR_ELx_SYS64_ISS_RT_SHIFT
;
487 regs
->regs
[rt
] = arm64_ftr_reg_ctrel0
.sys_val
;
492 unsigned int esr_mask
;
493 unsigned int esr_val
;
494 void (*handler
)(unsigned int esr
, struct pt_regs
*regs
);
497 static struct sys64_hook sys64_hooks
[] = {
499 .esr_mask
= ESR_ELx_SYS64_ISS_EL0_CACHE_OP_MASK
,
500 .esr_val
= ESR_ELx_SYS64_ISS_EL0_CACHE_OP_VAL
,
501 .handler
= user_cache_maint_handler
,
504 /* Trap read access to CTR_EL0 */
505 .esr_mask
= ESR_ELx_SYS64_ISS_SYS_OP_MASK
,
506 .esr_val
= ESR_ELx_SYS64_ISS_SYS_CTR_READ
,
507 .handler
= ctr_read_handler
,
512 asmlinkage
void __exception
do_sysinstr(unsigned int esr
, struct pt_regs
*regs
)
514 struct sys64_hook
*hook
;
516 for (hook
= sys64_hooks
; hook
->handler
; hook
++)
517 if ((hook
->esr_mask
& esr
) == hook
->esr_val
) {
518 hook
->handler(esr
, regs
);
522 force_signal_inject(SIGILL
, ILL_ILLOPC
, regs
, 0);
525 long compat_arm_syscall(struct pt_regs
*regs
);
527 asmlinkage
long do_ni_syscall(struct pt_regs
*regs
)
531 if (is_compat_task()) {
532 ret
= compat_arm_syscall(regs
);
538 if (show_unhandled_signals_ratelimited()) {
539 pr_info("%s[%d]: syscall %d\n", current
->comm
,
540 task_pid_nr(current
), (int)regs
->syscallno
);
541 dump_instr("", regs
);
546 return sys_ni_syscall();
549 static const char *esr_class_str
[] = {
550 [0 ... ESR_ELx_EC_MAX
] = "UNRECOGNIZED EC",
551 [ESR_ELx_EC_UNKNOWN
] = "Unknown/Uncategorized",
552 [ESR_ELx_EC_WFx
] = "WFI/WFE",
553 [ESR_ELx_EC_CP15_32
] = "CP15 MCR/MRC",
554 [ESR_ELx_EC_CP15_64
] = "CP15 MCRR/MRRC",
555 [ESR_ELx_EC_CP14_MR
] = "CP14 MCR/MRC",
556 [ESR_ELx_EC_CP14_LS
] = "CP14 LDC/STC",
557 [ESR_ELx_EC_FP_ASIMD
] = "ASIMD",
558 [ESR_ELx_EC_CP10_ID
] = "CP10 MRC/VMRS",
559 [ESR_ELx_EC_CP14_64
] = "CP14 MCRR/MRRC",
560 [ESR_ELx_EC_ILL
] = "PSTATE.IL",
561 [ESR_ELx_EC_SVC32
] = "SVC (AArch32)",
562 [ESR_ELx_EC_HVC32
] = "HVC (AArch32)",
563 [ESR_ELx_EC_SMC32
] = "SMC (AArch32)",
564 [ESR_ELx_EC_SVC64
] = "SVC (AArch64)",
565 [ESR_ELx_EC_HVC64
] = "HVC (AArch64)",
566 [ESR_ELx_EC_SMC64
] = "SMC (AArch64)",
567 [ESR_ELx_EC_SYS64
] = "MSR/MRS (AArch64)",
568 [ESR_ELx_EC_IMP_DEF
] = "EL3 IMP DEF",
569 [ESR_ELx_EC_IABT_LOW
] = "IABT (lower EL)",
570 [ESR_ELx_EC_IABT_CUR
] = "IABT (current EL)",
571 [ESR_ELx_EC_PC_ALIGN
] = "PC Alignment",
572 [ESR_ELx_EC_DABT_LOW
] = "DABT (lower EL)",
573 [ESR_ELx_EC_DABT_CUR
] = "DABT (current EL)",
574 [ESR_ELx_EC_SP_ALIGN
] = "SP Alignment",
575 [ESR_ELx_EC_FP_EXC32
] = "FP (AArch32)",
576 [ESR_ELx_EC_FP_EXC64
] = "FP (AArch64)",
577 [ESR_ELx_EC_SERROR
] = "SError",
578 [ESR_ELx_EC_BREAKPT_LOW
] = "Breakpoint (lower EL)",
579 [ESR_ELx_EC_BREAKPT_CUR
] = "Breakpoint (current EL)",
580 [ESR_ELx_EC_SOFTSTP_LOW
] = "Software Step (lower EL)",
581 [ESR_ELx_EC_SOFTSTP_CUR
] = "Software Step (current EL)",
582 [ESR_ELx_EC_WATCHPT_LOW
] = "Watchpoint (lower EL)",
583 [ESR_ELx_EC_WATCHPT_CUR
] = "Watchpoint (current EL)",
584 [ESR_ELx_EC_BKPT32
] = "BKPT (AArch32)",
585 [ESR_ELx_EC_VECTOR32
] = "Vector catch (AArch32)",
586 [ESR_ELx_EC_BRK64
] = "BRK (AArch64)",
589 const char *esr_get_class_string(u32 esr
)
591 return esr_class_str
[ESR_ELx_EC(esr
)];
595 * bad_mode handles the impossible case in the exception vector.
597 asmlinkage
void bad_mode(struct pt_regs
*regs
, int reason
, unsigned int esr
)
600 void __user
*pc
= (void __user
*)instruction_pointer(regs
);
603 pr_crit("Bad mode in %s handler detected on CPU%d, code 0x%08x -- %s\n",
604 handler
[reason
], smp_processor_id(), esr
,
605 esr_get_class_string(esr
));
608 info
.si_signo
= SIGILL
;
610 info
.si_code
= ILL_ILLOPC
;
613 arm64_notify_die("Oops - bad mode", regs
, &info
, 0);
616 void __pte_error(const char *file
, int line
, unsigned long val
)
618 pr_err("%s:%d: bad pte %016lx.\n", file
, line
, val
);
621 void __pmd_error(const char *file
, int line
, unsigned long val
)
623 pr_err("%s:%d: bad pmd %016lx.\n", file
, line
, val
);
626 void __pud_error(const char *file
, int line
, unsigned long val
)
628 pr_err("%s:%d: bad pud %016lx.\n", file
, line
, val
);
631 void __pgd_error(const char *file
, int line
, unsigned long val
)
633 pr_err("%s:%d: bad pgd %016lx.\n", file
, line
, val
);
636 /* GENERIC_BUG traps */
638 int is_valid_bugaddr(unsigned long addr
)
641 * bug_handler() only called for BRK #BUG_BRK_IMM.
642 * So the answer is trivial -- any spurious instances with no
643 * bug table entry will be rejected by report_bug() and passed
644 * back to the debug-monitors code and handled as a fatal
645 * unexpected debug exception.
650 static int bug_handler(struct pt_regs
*regs
, unsigned int esr
)
653 return DBG_HOOK_ERROR
;
655 switch (report_bug(regs
->pc
, regs
)) {
656 case BUG_TRAP_TYPE_BUG
:
657 die("Oops - BUG", regs
, 0);
660 case BUG_TRAP_TYPE_WARN
:
661 /* Ideally, report_bug() should backtrace for us... but no. */
662 dump_backtrace(regs
, NULL
);
666 /* unknown/unrecognised bug trap type */
667 return DBG_HOOK_ERROR
;
670 /* If thread survives, skip over the BUG instruction and continue: */
671 regs
->pc
+= AARCH64_INSN_SIZE
; /* skip BRK and resume */
672 return DBG_HOOK_HANDLED
;
675 static struct break_hook bug_break_hook
= {
676 .esr_val
= 0xf2000000 | BUG_BRK_IMM
,
677 .esr_mask
= 0xffffffff,
682 * Initial handler for AArch64 BRK exceptions
683 * This handler only used until debug_traps_init().
685 int __init
early_brk64(unsigned long addr
, unsigned int esr
,
686 struct pt_regs
*regs
)
688 return bug_handler(regs
, esr
) != DBG_HOOK_HANDLED
;
691 /* This registration must happen early, before debug_traps_init(). */
692 void __init
trap_init(void)
694 register_break_hook(&bug_break_hook
);