2 * linux/arch/arm/kernel/traps.c
4 * Copyright (C) 1995-2002 Russell King
5 * Fragments that appear the same as linux/arch/i386/kernel/traps.c (C) Linus Torvalds
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 * 'traps.c' handles hardware exceptions after we have saved some state in
12 * 'linux/arch/arm/lib/traps.S'. Mostly a debugging aid, but will probably
13 * kill the offending process.
15 #include <linux/module.h>
16 #include <linux/signal.h>
17 #include <linux/spinlock.h>
18 #include <linux/personality.h>
19 #include <linux/ptrace.h>
20 #include <linux/kallsyms.h>
21 #include <linux/delay.h>
22 #include <linux/init.h>
24 #include <asm/atomic.h>
25 #include <asm/cacheflush.h>
26 #include <asm/system.h>
27 #include <asm/uaccess.h>
28 #include <asm/unistd.h>
29 #include <asm/traps.h>
34 const char *processor_modes
[]=
35 { "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
36 "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
37 "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" ,
38 "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
41 static const char *handler
[]= { "prefetch abort", "data abort", "address exception", "interrupt" };
43 #ifdef CONFIG_DEBUG_USER
44 unsigned int user_debug
;
46 static int __init
user_debug_setup(char *str
)
48 get_option(&str
, &user_debug
);
51 __setup("user_debug=", user_debug_setup
);
54 void dump_backtrace_entry(unsigned long where
, unsigned long from
)
56 #ifdef CONFIG_KALLSYMS
57 printk("[<%08lx>] ", where
);
58 print_symbol("(%s) ", where
);
59 printk("from [<%08lx>] ", from
);
60 print_symbol("(%s)\n", from
);
62 printk("Function entered at [<%08lx>] from [<%08lx>]\n", where
, from
);
67 * Stack pointers should always be within the kernels view of
68 * physical memory. If it is not there, then we can't dump
69 * out any information relating to the stack.
71 static int verify_stack(unsigned long sp
)
73 if (sp
< PAGE_OFFSET
|| (sp
> (unsigned long)high_memory
&& high_memory
!= 0))
80 * Dump out the contents of some memory nicely...
82 static void dump_mem(const char *str
, unsigned long bottom
, unsigned long top
)
84 unsigned long p
= bottom
& ~31;
89 * We need to switch to kernel mode so that we can use __get_user
90 * to safely read from kernel space. Note that we now dump the
91 * code first, just in case the backtrace kills us.
96 printk("%s(0x%08lx to 0x%08lx)\n", str
, bottom
, top
);
98 for (p
= bottom
& ~31; p
< top
;) {
99 printk("%04lx: ", p
& 0xffff);
101 for (i
= 0; i
< 8; i
++, p
+= 4) {
104 if (p
< bottom
|| p
>= top
)
107 __get_user(val
, (unsigned long *)p
);
108 printk("%08x ", val
);
117 static void dump_instr(struct pt_regs
*regs
)
119 unsigned long addr
= instruction_pointer(regs
);
120 const int thumb
= thumb_mode(regs
);
121 const int width
= thumb
? 4 : 8;
126 * We need to switch to kernel mode so that we can use __get_user
127 * to safely read from kernel space. Note that we now dump the
128 * code first, just in case the backtrace kills us.
134 for (i
= -4; i
< 1; i
++) {
135 unsigned int val
, bad
;
138 bad
= __get_user(val
, &((u16
*)addr
)[i
]);
140 bad
= __get_user(val
, &((u32
*)addr
)[i
]);
143 printk(i
== 0 ? "(%0*x) " : "%0*x ", width
, val
);
145 printk("bad PC value.");
154 static void dump_backtrace(struct pt_regs
*regs
, struct task_struct
*tsk
)
159 printk("Backtrace: ");
162 printk("no frame pointer");
164 } else if (verify_stack(fp
)) {
165 printk("invalid frame pointer 0x%08x", fp
);
167 } else if (fp
< (unsigned long)end_of_stack(tsk
))
168 printk("frame pointer underflow");
172 c_backtrace(fp
, processor_mode(regs
));
175 void dump_stack(void)
177 #ifdef CONFIG_DEBUG_ERRORS
182 EXPORT_SYMBOL(dump_stack
);
184 void show_stack(struct task_struct
*tsk
, unsigned long *sp
)
192 fp
= thread_saved_fp(tsk
);
194 asm("mov %0, fp" : "=r" (fp
) : : "cc");
196 c_backtrace(fp
, 0x10);
200 static void __die(const char *str
, int err
, struct thread_info
*thread
, struct pt_regs
*regs
)
202 struct task_struct
*tsk
= thread
->task
;
203 static int die_counter
;
205 printk("Internal error: %s: %x [#%d]\n", str
, err
, ++die_counter
);
208 printk("Process %s (pid: %d, stack limit = 0x%p)\n",
209 tsk
->comm
, tsk
->pid
, thread
+ 1);
211 if (!user_mode(regs
) || in_interrupt()) {
212 dump_mem("Stack: ", regs
->ARM_sp
,
213 THREAD_SIZE
+ (unsigned long)task_stack_page(tsk
));
214 dump_backtrace(regs
, tsk
);
219 DEFINE_SPINLOCK(die_lock
);
222 * This function is protected against re-entrancy.
224 NORET_TYPE
void die(const char *str
, struct pt_regs
*regs
, int err
)
226 struct thread_info
*thread
= current_thread_info();
229 spin_lock_irq(&die_lock
);
231 __die(str
, err
, thread
, regs
);
233 spin_unlock_irq(&die_lock
);
236 panic("Fatal exception");
241 void notify_die(const char *str
, struct pt_regs
*regs
, struct siginfo
*info
,
242 unsigned long err
, unsigned long trap
)
244 if (user_mode(regs
)) {
245 current
->thread
.error_code
= err
;
246 current
->thread
.trap_no
= trap
;
248 force_sig_info(info
->si_signo
, info
, current
);
254 static LIST_HEAD(undef_hook
);
255 static DEFINE_SPINLOCK(undef_lock
);
257 void register_undef_hook(struct undef_hook
*hook
)
261 spin_lock_irqsave(&undef_lock
, flags
);
262 list_add(&hook
->node
, &undef_hook
);
263 spin_unlock_irqrestore(&undef_lock
, flags
);
266 void unregister_undef_hook(struct undef_hook
*hook
)
270 spin_lock_irqsave(&undef_lock
, flags
);
271 list_del(&hook
->node
);
272 spin_unlock_irqrestore(&undef_lock
, flags
);
275 asmlinkage
void do_undefinstr(struct pt_regs
*regs
)
277 unsigned int correction
= thumb_mode(regs
) ? 2 : 4;
279 struct undef_hook
*hook
;
284 * According to the ARM ARM, PC is 2 or 4 bytes ahead,
285 * depending whether we're in Thumb mode or not.
286 * Correct this offset.
288 regs
->ARM_pc
-= correction
;
290 pc
= (void __user
*)instruction_pointer(regs
);
291 if (thumb_mode(regs
)) {
292 get_user(instr
, (u16 __user
*)pc
);
294 get_user(instr
, (u32 __user
*)pc
);
297 spin_lock_irq(&undef_lock
);
298 list_for_each_entry(hook
, &undef_hook
, node
) {
299 if ((instr
& hook
->instr_mask
) == hook
->instr_val
&&
300 (regs
->ARM_cpsr
& hook
->cpsr_mask
) == hook
->cpsr_val
) {
301 if (hook
->fn(regs
, instr
) == 0) {
302 spin_unlock_irq(&undef_lock
);
307 spin_unlock_irq(&undef_lock
);
309 #ifdef CONFIG_DEBUG_USER
310 if (user_debug
& UDBG_UNDEFINED
) {
311 printk(KERN_INFO
"%s (%d): undefined instruction: pc=%p\n",
312 current
->comm
, current
->pid
, pc
);
317 info
.si_signo
= SIGILL
;
319 info
.si_code
= ILL_ILLOPC
;
322 notify_die("Oops - undefined instruction", regs
, &info
, 0, 6);
325 asmlinkage
void do_unexp_fiq (struct pt_regs
*regs
)
327 #ifndef CONFIG_IGNORE_FIQ
328 printk("Hmm. Unexpected FIQ received, but trying to continue\n");
329 printk("You may have a hardware problem...\n");
334 * bad_mode handles the impossible case in the vectors. If you see one of
335 * these, then it's extremely serious, and could mean you have buggy hardware.
336 * It never returns, and never tries to sync. We hope that we can at least
337 * dump out some state information...
339 asmlinkage
void bad_mode(struct pt_regs
*regs
, int reason
, int proc_mode
)
343 printk(KERN_CRIT
"Bad mode in %s handler detected: mode %s\n",
344 handler
[reason
], processor_modes
[proc_mode
]);
346 die("Oops - bad mode", regs
, 0);
351 static int bad_syscall(int n
, struct pt_regs
*regs
)
353 struct thread_info
*thread
= current_thread_info();
356 if (current
->personality
!= PER_LINUX
&&
357 current
->personality
!= PER_LINUX_32BIT
&&
358 thread
->exec_domain
->handler
) {
359 thread
->exec_domain
->handler(n
, regs
);
363 #ifdef CONFIG_DEBUG_USER
364 if (user_debug
& UDBG_SYSCALL
) {
365 printk(KERN_ERR
"[%d] %s: obsolete system call %08x.\n",
366 current
->pid
, current
->comm
, n
);
371 info
.si_signo
= SIGILL
;
373 info
.si_code
= ILL_ILLTRP
;
374 info
.si_addr
= (void __user
*)instruction_pointer(regs
) -
375 (thumb_mode(regs
) ? 2 : 4);
377 notify_die("Oops - bad syscall", regs
, &info
, n
, 0);
383 do_cache_op(unsigned long start
, unsigned long end
, int flags
)
385 struct vm_area_struct
*vma
;
387 if (end
< start
|| flags
)
390 vma
= find_vma(current
->active_mm
, start
);
391 if (vma
&& vma
->vm_start
< end
) {
392 if (start
< vma
->vm_start
)
393 start
= vma
->vm_start
;
394 if (end
> vma
->vm_end
)
397 flush_cache_user_range(vma
, start
, end
);
402 * Handle all unrecognised system calls.
403 * 0x9f0000 - 0x9fffff are some more esoteric system calls
405 #define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
406 asmlinkage
int arm_syscall(int no
, struct pt_regs
*regs
)
408 struct thread_info
*thread
= current_thread_info();
411 if ((no
>> 16) != (__ARM_NR_BASE
>> 16))
412 return bad_syscall(no
, regs
);
414 switch (no
& 0xffff) {
415 case 0: /* branch through 0 */
416 info
.si_signo
= SIGSEGV
;
418 info
.si_code
= SEGV_MAPERR
;
421 notify_die("branch through zero", regs
, &info
, 0, 0);
424 case NR(breakpoint
): /* SWI BREAK_POINT */
425 regs
->ARM_pc
-= thumb_mode(regs
) ? 2 : 4;
426 ptrace_break(current
, regs
);
430 * Flush a region from virtual address 'r0' to virtual address 'r1'
431 * _exclusive_. There is no alignment requirement on either address;
432 * user space does not need to know the hardware cache layout.
434 * r2 contains flags. It should ALWAYS be passed as ZERO until it
435 * is defined to be something else. For now we ignore it, but may
436 * the fires of hell burn in your belly if you break this rule. ;)
438 * (at a later date, we may want to allow this call to not flush
439 * various aspects of the cache. Passing '0' will guarantee that
440 * everything necessary gets flushed to maintain consistency in
441 * the specified region).
444 do_cache_op(regs
->ARM_r0
, regs
->ARM_r1
, regs
->ARM_r2
);
448 if (!(elf_hwcap
& HWCAP_26BIT
))
450 regs
->ARM_cpsr
&= ~MODE32_BIT
;
454 if (!(elf_hwcap
& HWCAP_26BIT
))
456 regs
->ARM_cpsr
|= MODE32_BIT
;
460 thread
->tp_value
= regs
->ARM_r0
;
461 #if defined(CONFIG_HAS_TLS_REG)
462 asm ("mcr p15, 0, %0, c13, c0, 3" : : "r" (regs
->ARM_r0
) );
463 #elif !defined(CONFIG_TLS_REG_EMUL)
465 * User space must never try to access this directly.
466 * Expect your app to break eventually if you do so.
467 * The user helper at 0xffff0fe0 must be used instead.
468 * (see entry-armv.S for details)
470 *((unsigned int *)0xffff0ff0) = regs
->ARM_r0
;
474 #ifdef CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG
476 * Atomically store r1 in *r2 if *r2 is equal to r0 for user space.
477 * Return zero in r0 if *MEM was changed or non-zero if no exchange
478 * happened. Also set the user C flag accordingly.
479 * If access permissions have to be fixed up then non-zero is
480 * returned and the operation has to be re-attempted.
482 * *NOTE*: This is a ghost syscall private to the kernel. Only the
483 * __kuser_cmpxchg code in entry-armv.S should be aware of its
484 * existence. Don't ever use this from user code.
488 extern void do_DataAbort(unsigned long addr
, unsigned int fsr
,
489 struct pt_regs
*regs
);
491 unsigned long addr
= regs
->ARM_r2
;
492 struct mm_struct
*mm
= current
->mm
;
493 pgd_t
*pgd
; pmd_t
*pmd
; pte_t
*pte
;
496 regs
->ARM_cpsr
&= ~PSR_C_BIT
;
497 down_read(&mm
->mmap_sem
);
498 pgd
= pgd_offset(mm
, addr
);
499 if (!pgd_present(*pgd
))
501 pmd
= pmd_offset(pgd
, addr
);
502 if (!pmd_present(*pmd
))
504 pte
= pte_offset_map_lock(mm
, pmd
, addr
, &ptl
);
505 if (!pte_present(*pte
) || !pte_dirty(*pte
)) {
506 pte_unmap_unlock(pte
, ptl
);
509 val
= *(unsigned long *)addr
;
512 *(unsigned long *)addr
= regs
->ARM_r1
;
513 regs
->ARM_cpsr
|= PSR_C_BIT
;
515 pte_unmap_unlock(pte
, ptl
);
516 up_read(&mm
->mmap_sem
);
520 up_read(&mm
->mmap_sem
);
521 /* simulate a write access fault */
522 do_DataAbort(addr
, 15 + (1 << 11), regs
);
528 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS
529 if not implemented, rather than raising SIGILL. This
530 way the calling program can gracefully determine whether
531 a feature is supported. */
536 #ifdef CONFIG_DEBUG_USER
538 * experience shows that these seem to indicate that
539 * something catastrophic has happened
541 if (user_debug
& UDBG_SYSCALL
) {
542 printk("[%d] %s: arm syscall %d\n",
543 current
->pid
, current
->comm
, no
);
545 if (user_mode(regs
)) {
547 c_backtrace(regs
->ARM_fp
, processor_mode(regs
));
551 info
.si_signo
= SIGILL
;
553 info
.si_code
= ILL_ILLTRP
;
554 info
.si_addr
= (void __user
*)instruction_pointer(regs
) -
555 (thumb_mode(regs
) ? 2 : 4);
557 notify_die("Oops - bad syscall(2)", regs
, &info
, no
, 0);
561 #ifdef CONFIG_TLS_REG_EMUL
564 * We might be running on an ARMv6+ processor which should have the TLS
565 * register but for some reason we can't use it, or maybe an SMP system
566 * using a pre-ARMv6 processor (there are apparently a few prototypes like
567 * that in existence) and therefore access to that register must be
571 static int get_tp_trap(struct pt_regs
*regs
, unsigned int instr
)
573 int reg
= (instr
>> 12) & 15;
576 regs
->uregs
[reg
] = current_thread_info()->tp_value
;
581 static struct undef_hook arm_mrc_hook
= {
582 .instr_mask
= 0x0fff0fff,
583 .instr_val
= 0x0e1d0f70,
584 .cpsr_mask
= PSR_T_BIT
,
589 static int __init
arm_mrc_hook_init(void)
591 register_undef_hook(&arm_mrc_hook
);
595 late_initcall(arm_mrc_hook_init
);
599 void __bad_xchg(volatile void *ptr
, int size
)
601 printk("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n",
602 __builtin_return_address(0), ptr
, size
);
605 EXPORT_SYMBOL(__bad_xchg
);
608 * A data abort trap was taken, but we did not handle the instruction.
609 * Try to abort the user program, or panic if it was the kernel.
612 baddataabort(int code
, unsigned long instr
, struct pt_regs
*regs
)
614 unsigned long addr
= instruction_pointer(regs
);
617 #ifdef CONFIG_DEBUG_USER
618 if (user_debug
& UDBG_BADABORT
) {
619 printk(KERN_ERR
"[%d] %s: bad data abort: code %d instr 0x%08lx\n",
620 current
->pid
, current
->comm
, code
, instr
);
622 show_pte(current
->mm
, addr
);
626 info
.si_signo
= SIGILL
;
628 info
.si_code
= ILL_ILLOPC
;
629 info
.si_addr
= (void __user
*)addr
;
631 notify_die("unknown data abort code", regs
, &info
, instr
, 0);
634 void __attribute__((noreturn
)) __bug(const char *file
, int line
)
636 printk(KERN_CRIT
"kernel BUG at %s:%d!\n", file
, line
);
639 /* Avoid "noreturn function does return" */
642 EXPORT_SYMBOL(__bug
);
644 void __readwrite_bug(const char *fn
)
646 printk("%s called, but not implemented\n", fn
);
649 EXPORT_SYMBOL(__readwrite_bug
);
651 void __pte_error(const char *file
, int line
, unsigned long val
)
653 printk("%s:%d: bad pte %08lx.\n", file
, line
, val
);
656 void __pmd_error(const char *file
, int line
, unsigned long val
)
658 printk("%s:%d: bad pmd %08lx.\n", file
, line
, val
);
661 void __pgd_error(const char *file
, int line
, unsigned long val
)
663 printk("%s:%d: bad pgd %08lx.\n", file
, line
, val
);
666 asmlinkage
void __div0(void)
668 printk("Division by zero in kernel.\n");
671 EXPORT_SYMBOL(__div0
);
677 /* if that doesn't kill us, halt */
678 panic("Oops failed to kill thread");
680 EXPORT_SYMBOL(abort
);
682 void __init
trap_init(void)
684 unsigned long vectors
= CONFIG_VECTORS_BASE
;
685 extern char __stubs_start
[], __stubs_end
[];
686 extern char __vectors_start
[], __vectors_end
[];
687 extern char __kuser_helper_start
[], __kuser_helper_end
[];
688 int kuser_sz
= __kuser_helper_end
- __kuser_helper_start
;
691 * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
692 * into the vector page, mapped at 0xffff0000, and ensure these
693 * are visible to the instruction stream.
695 memcpy((void *)vectors
, __vectors_start
, __vectors_end
- __vectors_start
);
696 memcpy((void *)vectors
+ 0x200, __stubs_start
, __stubs_end
- __stubs_start
);
697 memcpy((void *)vectors
+ 0x1000 - kuser_sz
, __kuser_helper_start
, kuser_sz
);
700 * Copy signal return handlers into the vector page, and
701 * set sigreturn to be a pointer to these.
703 memcpy((void *)KERN_SIGRETURN_CODE
, sigreturn_codes
,
704 sizeof(sigreturn_codes
));
706 flush_icache_range(vectors
, vectors
+ PAGE_SIZE
);
707 modify_domain(DOMAIN_USER
, DOMAIN_CLIENT
);