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git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - arch/arm/kernel/traps.c
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
));
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 printk(KERN_EMERG
"Fatal exception: panic in 5 seconds\n");
238 panic("Fatal exception");
244 void notify_die(const char *str
, struct pt_regs
*regs
, struct siginfo
*info
,
245 unsigned long err
, unsigned long trap
)
247 if (user_mode(regs
)) {
248 current
->thread
.error_code
= err
;
249 current
->thread
.trap_no
= trap
;
251 force_sig_info(info
->si_signo
, info
, current
);
257 static LIST_HEAD(undef_hook
);
258 static DEFINE_SPINLOCK(undef_lock
);
260 void register_undef_hook(struct undef_hook
*hook
)
264 spin_lock_irqsave(&undef_lock
, flags
);
265 list_add(&hook
->node
, &undef_hook
);
266 spin_unlock_irqrestore(&undef_lock
, flags
);
269 void unregister_undef_hook(struct undef_hook
*hook
)
273 spin_lock_irqsave(&undef_lock
, flags
);
274 list_del(&hook
->node
);
275 spin_unlock_irqrestore(&undef_lock
, flags
);
278 asmlinkage
void do_undefinstr(struct pt_regs
*regs
)
280 unsigned int correction
= thumb_mode(regs
) ? 2 : 4;
282 struct undef_hook
*hook
;
287 * According to the ARM ARM, PC is 2 or 4 bytes ahead,
288 * depending whether we're in Thumb mode or not.
289 * Correct this offset.
291 regs
->ARM_pc
-= correction
;
293 pc
= (void __user
*)instruction_pointer(regs
);
294 if (thumb_mode(regs
)) {
295 get_user(instr
, (u16 __user
*)pc
);
297 get_user(instr
, (u32 __user
*)pc
);
300 spin_lock_irq(&undef_lock
);
301 list_for_each_entry(hook
, &undef_hook
, node
) {
302 if ((instr
& hook
->instr_mask
) == hook
->instr_val
&&
303 (regs
->ARM_cpsr
& hook
->cpsr_mask
) == hook
->cpsr_val
) {
304 if (hook
->fn(regs
, instr
) == 0) {
305 spin_unlock_irq(&undef_lock
);
310 spin_unlock_irq(&undef_lock
);
312 #ifdef CONFIG_DEBUG_USER
313 if (user_debug
& UDBG_UNDEFINED
) {
314 printk(KERN_INFO
"%s (%d): undefined instruction: pc=%p\n",
315 current
->comm
, current
->pid
, pc
);
320 info
.si_signo
= SIGILL
;
322 info
.si_code
= ILL_ILLOPC
;
325 notify_die("Oops - undefined instruction", regs
, &info
, 0, 6);
328 asmlinkage
void do_unexp_fiq (struct pt_regs
*regs
)
330 #ifndef CONFIG_IGNORE_FIQ
331 printk("Hmm. Unexpected FIQ received, but trying to continue\n");
332 printk("You may have a hardware problem...\n");
337 * bad_mode handles the impossible case in the vectors. If you see one of
338 * these, then it's extremely serious, and could mean you have buggy hardware.
339 * It never returns, and never tries to sync. We hope that we can at least
340 * dump out some state information...
342 asmlinkage
void bad_mode(struct pt_regs
*regs
, int reason
, int proc_mode
)
346 printk(KERN_CRIT
"Bad mode in %s handler detected: mode %s\n",
347 handler
[reason
], processor_modes
[proc_mode
]);
349 die("Oops - bad mode", regs
, 0);
354 static int bad_syscall(int n
, struct pt_regs
*regs
)
356 struct thread_info
*thread
= current_thread_info();
359 if (current
->personality
!= PER_LINUX
&&
360 current
->personality
!= PER_LINUX_32BIT
&&
361 thread
->exec_domain
->handler
) {
362 thread
->exec_domain
->handler(n
, regs
);
366 #ifdef CONFIG_DEBUG_USER
367 if (user_debug
& UDBG_SYSCALL
) {
368 printk(KERN_ERR
"[%d] %s: obsolete system call %08x.\n",
369 current
->pid
, current
->comm
, n
);
374 info
.si_signo
= SIGILL
;
376 info
.si_code
= ILL_ILLTRP
;
377 info
.si_addr
= (void __user
*)instruction_pointer(regs
) -
378 (thumb_mode(regs
) ? 2 : 4);
380 notify_die("Oops - bad syscall", regs
, &info
, n
, 0);
386 do_cache_op(unsigned long start
, unsigned long end
, int flags
)
388 struct vm_area_struct
*vma
;
390 if (end
< start
|| flags
)
393 vma
= find_vma(current
->active_mm
, start
);
394 if (vma
&& vma
->vm_start
< end
) {
395 if (start
< vma
->vm_start
)
396 start
= vma
->vm_start
;
397 if (end
> vma
->vm_end
)
400 flush_cache_user_range(vma
, start
, end
);
405 * Handle all unrecognised system calls.
406 * 0x9f0000 - 0x9fffff are some more esoteric system calls
408 #define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
409 asmlinkage
int arm_syscall(int no
, struct pt_regs
*regs
)
411 struct thread_info
*thread
= current_thread_info();
414 if ((no
>> 16) != (__ARM_NR_BASE
>> 16))
415 return bad_syscall(no
, regs
);
417 switch (no
& 0xffff) {
418 case 0: /* branch through 0 */
419 info
.si_signo
= SIGSEGV
;
421 info
.si_code
= SEGV_MAPERR
;
424 notify_die("branch through zero", regs
, &info
, 0, 0);
427 case NR(breakpoint
): /* SWI BREAK_POINT */
428 regs
->ARM_pc
-= thumb_mode(regs
) ? 2 : 4;
429 ptrace_break(current
, regs
);
433 * Flush a region from virtual address 'r0' to virtual address 'r1'
434 * _exclusive_. There is no alignment requirement on either address;
435 * user space does not need to know the hardware cache layout.
437 * r2 contains flags. It should ALWAYS be passed as ZERO until it
438 * is defined to be something else. For now we ignore it, but may
439 * the fires of hell burn in your belly if you break this rule. ;)
441 * (at a later date, we may want to allow this call to not flush
442 * various aspects of the cache. Passing '0' will guarantee that
443 * everything necessary gets flushed to maintain consistency in
444 * the specified region).
447 do_cache_op(regs
->ARM_r0
, regs
->ARM_r1
, regs
->ARM_r2
);
451 if (!(elf_hwcap
& HWCAP_26BIT
))
453 regs
->ARM_cpsr
&= ~MODE32_BIT
;
457 if (!(elf_hwcap
& HWCAP_26BIT
))
459 regs
->ARM_cpsr
|= MODE32_BIT
;
463 thread
->tp_value
= regs
->ARM_r0
;
464 #if defined(CONFIG_HAS_TLS_REG)
465 asm ("mcr p15, 0, %0, c13, c0, 3" : : "r" (regs
->ARM_r0
) );
466 #elif !defined(CONFIG_TLS_REG_EMUL)
468 * User space must never try to access this directly.
469 * Expect your app to break eventually if you do so.
470 * The user helper at 0xffff0fe0 must be used instead.
471 * (see entry-armv.S for details)
473 *((unsigned int *)0xffff0ff0) = regs
->ARM_r0
;
477 #ifdef CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG
479 * Atomically store r1 in *r2 if *r2 is equal to r0 for user space.
480 * Return zero in r0 if *MEM was changed or non-zero if no exchange
481 * happened. Also set the user C flag accordingly.
482 * If access permissions have to be fixed up then non-zero is
483 * returned and the operation has to be re-attempted.
485 * *NOTE*: This is a ghost syscall private to the kernel. Only the
486 * __kuser_cmpxchg code in entry-armv.S should be aware of its
487 * existence. Don't ever use this from user code.
491 extern void do_DataAbort(unsigned long addr
, unsigned int fsr
,
492 struct pt_regs
*regs
);
494 unsigned long addr
= regs
->ARM_r2
;
495 struct mm_struct
*mm
= current
->mm
;
496 pgd_t
*pgd
; pmd_t
*pmd
; pte_t
*pte
;
499 regs
->ARM_cpsr
&= ~PSR_C_BIT
;
500 down_read(&mm
->mmap_sem
);
501 pgd
= pgd_offset(mm
, addr
);
502 if (!pgd_present(*pgd
))
504 pmd
= pmd_offset(pgd
, addr
);
505 if (!pmd_present(*pmd
))
507 pte
= pte_offset_map_lock(mm
, pmd
, addr
, &ptl
);
508 if (!pte_present(*pte
) || !pte_dirty(*pte
)) {
509 pte_unmap_unlock(pte
, ptl
);
512 val
= *(unsigned long *)addr
;
515 *(unsigned long *)addr
= regs
->ARM_r1
;
516 regs
->ARM_cpsr
|= PSR_C_BIT
;
518 pte_unmap_unlock(pte
, ptl
);
519 up_read(&mm
->mmap_sem
);
523 up_read(&mm
->mmap_sem
);
524 /* simulate a write access fault */
525 do_DataAbort(addr
, 15 + (1 << 11), regs
);
531 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS
532 if not implemented, rather than raising SIGILL. This
533 way the calling program can gracefully determine whether
534 a feature is supported. */
539 #ifdef CONFIG_DEBUG_USER
541 * experience shows that these seem to indicate that
542 * something catastrophic has happened
544 if (user_debug
& UDBG_SYSCALL
) {
545 printk("[%d] %s: arm syscall %d\n",
546 current
->pid
, current
->comm
, no
);
548 if (user_mode(regs
)) {
550 c_backtrace(regs
->ARM_fp
, processor_mode(regs
));
554 info
.si_signo
= SIGILL
;
556 info
.si_code
= ILL_ILLTRP
;
557 info
.si_addr
= (void __user
*)instruction_pointer(regs
) -
558 (thumb_mode(regs
) ? 2 : 4);
560 notify_die("Oops - bad syscall(2)", regs
, &info
, no
, 0);
564 #ifdef CONFIG_TLS_REG_EMUL
567 * We might be running on an ARMv6+ processor which should have the TLS
568 * register but for some reason we can't use it, or maybe an SMP system
569 * using a pre-ARMv6 processor (there are apparently a few prototypes like
570 * that in existence) and therefore access to that register must be
574 static int get_tp_trap(struct pt_regs
*regs
, unsigned int instr
)
576 int reg
= (instr
>> 12) & 15;
579 regs
->uregs
[reg
] = current_thread_info()->tp_value
;
584 static struct undef_hook arm_mrc_hook
= {
585 .instr_mask
= 0x0fff0fff,
586 .instr_val
= 0x0e1d0f70,
587 .cpsr_mask
= PSR_T_BIT
,
592 static int __init
arm_mrc_hook_init(void)
594 register_undef_hook(&arm_mrc_hook
);
598 late_initcall(arm_mrc_hook_init
);
602 void __bad_xchg(volatile void *ptr
, int size
)
604 printk("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n",
605 __builtin_return_address(0), ptr
, size
);
608 EXPORT_SYMBOL(__bad_xchg
);
611 * A data abort trap was taken, but we did not handle the instruction.
612 * Try to abort the user program, or panic if it was the kernel.
615 baddataabort(int code
, unsigned long instr
, struct pt_regs
*regs
)
617 unsigned long addr
= instruction_pointer(regs
);
620 #ifdef CONFIG_DEBUG_USER
621 if (user_debug
& UDBG_BADABORT
) {
622 printk(KERN_ERR
"[%d] %s: bad data abort: code %d instr 0x%08lx\n",
623 current
->pid
, current
->comm
, code
, instr
);
625 show_pte(current
->mm
, addr
);
629 info
.si_signo
= SIGILL
;
631 info
.si_code
= ILL_ILLOPC
;
632 info
.si_addr
= (void __user
*)addr
;
634 notify_die("unknown data abort code", regs
, &info
, instr
, 0);
637 void __attribute__((noreturn
)) __bug(const char *file
, int line
, void *data
)
639 printk(KERN_CRIT
"kernel BUG at %s:%d!", file
, line
);
641 printk(" - extra data = %p", data
);
645 /* Avoid "noreturn function does return" */
648 EXPORT_SYMBOL(__bug
);
650 void __readwrite_bug(const char *fn
)
652 printk("%s called, but not implemented\n", fn
);
655 EXPORT_SYMBOL(__readwrite_bug
);
657 void __pte_error(const char *file
, int line
, unsigned long val
)
659 printk("%s:%d: bad pte %08lx.\n", file
, line
, val
);
662 void __pmd_error(const char *file
, int line
, unsigned long val
)
664 printk("%s:%d: bad pmd %08lx.\n", file
, line
, val
);
667 void __pgd_error(const char *file
, int line
, unsigned long val
)
669 printk("%s:%d: bad pgd %08lx.\n", file
, line
, val
);
672 asmlinkage
void __div0(void)
674 printk("Division by zero in kernel.\n");
677 EXPORT_SYMBOL(__div0
);
683 /* if that doesn't kill us, halt */
684 panic("Oops failed to kill thread");
686 EXPORT_SYMBOL(abort
);
688 void __init
trap_init(void)
690 unsigned long vectors
= CONFIG_VECTORS_BASE
;
691 extern char __stubs_start
[], __stubs_end
[];
692 extern char __vectors_start
[], __vectors_end
[];
693 extern char __kuser_helper_start
[], __kuser_helper_end
[];
694 int kuser_sz
= __kuser_helper_end
- __kuser_helper_start
;
697 * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
698 * into the vector page, mapped at 0xffff0000, and ensure these
699 * are visible to the instruction stream.
701 memcpy((void *)vectors
, __vectors_start
, __vectors_end
- __vectors_start
);
702 memcpy((void *)vectors
+ 0x200, __stubs_start
, __stubs_end
- __stubs_start
);
703 memcpy((void *)vectors
+ 0x1000 - kuser_sz
, __kuser_helper_start
, kuser_sz
);
706 * Copy signal return handlers into the vector page, and
707 * set sigreturn to be a pointer to these.
709 memcpy((void *)KERN_SIGRETURN_CODE
, sigreturn_codes
,
710 sizeof(sigreturn_codes
));
712 flush_icache_range(vectors
, vectors
+ PAGE_SIZE
);
713 modify_domain(DOMAIN_USER
, DOMAIN_CLIENT
);