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1/*
2 * linux/arch/arm/kernel/traps.c
3 *
4 * Copyright (C) 1995-2009 Russell King
5 * Fragments that appear the same as linux/arch/i386/kernel/traps.c (C) Linus Torvalds
6 *
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.
10 *
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.
14 */
15#include <linux/signal.h>
16#include <linux/personality.h>
17#include <linux/kallsyms.h>
18#include <linux/spinlock.h>
19#include <linux/uaccess.h>
20#include <linux/hardirq.h>
21#include <linux/kdebug.h>
22#include <linux/module.h>
23#include <linux/kexec.h>
24#include <linux/delay.h>
25#include <linux/init.h>
26#include <linux/sched.h>
27
28#include <linux/atomic.h>
29#include <asm/cacheflush.h>
30#include <asm/system.h>
31#include <asm/unistd.h>
32#include <asm/traps.h>
33#include <asm/unwind.h>
34#include <asm/tls.h>
35
36#include "signal.h"
37
38static const char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" };
39
40void *vectors_page;
41
42#ifdef CONFIG_DEBUG_USER
43unsigned int user_debug;
44
45static int __init user_debug_setup(char *str)
46{
47 get_option(&str, &user_debug);
48 return 1;
49}
50__setup("user_debug=", user_debug_setup);
51#endif
52
53static void dump_mem(const char *, const char *, unsigned long, unsigned long);
54
55void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame)
56{
57#ifdef CONFIG_KALLSYMS
58 printk("[<%08lx>] (%pS) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from);
59#else
60 printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
61#endif
62
63 if (in_exception_text(where))
64 dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs));
65}
66
67#ifndef CONFIG_ARM_UNWIND
68/*
69 * Stack pointers should always be within the kernels view of
70 * physical memory. If it is not there, then we can't dump
71 * out any information relating to the stack.
72 */
73static int verify_stack(unsigned long sp)
74{
75 if (sp < PAGE_OFFSET ||
76 (sp > (unsigned long)high_memory && high_memory != NULL))
77 return -EFAULT;
78
79 return 0;
80}
81#endif
82
83/*
84 * Dump out the contents of some memory nicely...
85 */
86static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
87 unsigned long top)
88{
89 unsigned long first;
90 mm_segment_t fs;
91 int i;
92
93 /*
94 * We need to switch to kernel mode so that we can use __get_user
95 * to safely read from kernel space. Note that we now dump the
96 * code first, just in case the backtrace kills us.
97 */
98 fs = get_fs();
99 set_fs(KERNEL_DS);
100
101 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top);
102
103 for (first = bottom & ~31; first < top; first += 32) {
104 unsigned long p;
105 char str[sizeof(" 12345678") * 8 + 1];
106
107 memset(str, ' ', sizeof(str));
108 str[sizeof(str) - 1] = '\0';
109
110 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
111 if (p >= bottom && p < top) {
112 unsigned long val;
113 if (__get_user(val, (unsigned long *)p) == 0)
114 sprintf(str + i * 9, " %08lx", val);
115 else
116 sprintf(str + i * 9, " ????????");
117 }
118 }
119 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
120 }
121
122 set_fs(fs);
123}
124
125static void dump_instr(const char *lvl, struct pt_regs *regs)
126{
127 unsigned long addr = instruction_pointer(regs);
128 const int thumb = thumb_mode(regs);
129 const int width = thumb ? 4 : 8;
130 mm_segment_t fs;
131 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
132 int i;
133
134 /*
135 * We need to switch to kernel mode so that we can use __get_user
136 * to safely read from kernel space. Note that we now dump the
137 * code first, just in case the backtrace kills us.
138 */
139 fs = get_fs();
140 set_fs(KERNEL_DS);
141
142 for (i = -4; i < 1 + !!thumb; i++) {
143 unsigned int val, bad;
144
145 if (thumb)
146 bad = __get_user(val, &((u16 *)addr)[i]);
147 else
148 bad = __get_user(val, &((u32 *)addr)[i]);
149
150 if (!bad)
151 p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ",
152 width, val);
153 else {
154 p += sprintf(p, "bad PC value");
155 break;
156 }
157 }
158 printk("%sCode: %s\n", lvl, str);
159
160 set_fs(fs);
161}
162
163#ifdef CONFIG_ARM_UNWIND
164static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
165{
166 unwind_backtrace(regs, tsk);
167}
168#else
169static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
170{
171 unsigned int fp, mode;
172 int ok = 1;
173
174 printk("Backtrace: ");
175
176 if (!tsk)
177 tsk = current;
178
179 if (regs) {
180 fp = regs->ARM_fp;
181 mode = processor_mode(regs);
182 } else if (tsk != current) {
183 fp = thread_saved_fp(tsk);
184 mode = 0x10;
185 } else {
186 asm("mov %0, fp" : "=r" (fp) : : "cc");
187 mode = 0x10;
188 }
189
190 if (!fp) {
191 printk("no frame pointer");
192 ok = 0;
193 } else if (verify_stack(fp)) {
194 printk("invalid frame pointer 0x%08x", fp);
195 ok = 0;
196 } else if (fp < (unsigned long)end_of_stack(tsk))
197 printk("frame pointer underflow");
198 printk("\n");
199
200 if (ok)
201 c_backtrace(fp, mode);
202}
203#endif
204
205void dump_stack(void)
206{
207 dump_backtrace(NULL, NULL);
208}
209
210EXPORT_SYMBOL(dump_stack);
211
212void show_stack(struct task_struct *tsk, unsigned long *sp)
213{
214 dump_backtrace(NULL, tsk);
215 barrier();
216}
217
218#ifdef CONFIG_PREEMPT
219#define S_PREEMPT " PREEMPT"
220#else
221#define S_PREEMPT ""
222#endif
223#ifdef CONFIG_SMP
224#define S_SMP " SMP"
225#else
226#define S_SMP ""
227#endif
228
229static int __die(const char *str, int err, struct thread_info *thread, struct pt_regs *regs)
230{
231 struct task_struct *tsk = thread->task;
232 static int die_counter;
233 int ret;
234
235 printk(KERN_EMERG "Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
236 str, err, ++die_counter);
237
238 /* trap and error numbers are mostly meaningless on ARM */
239 ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV);
240 if (ret == NOTIFY_STOP)
241 return ret;
242
243 print_modules();
244 __show_regs(regs);
245 printk(KERN_EMERG "Process %.*s (pid: %d, stack limit = 0x%p)\n",
246 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1);
247
248 if (!user_mode(regs) || in_interrupt()) {
249 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp,
250 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
251 dump_backtrace(regs, tsk);
252 dump_instr(KERN_EMERG, regs);
253 }
254
255 return ret;
256}
257
258static DEFINE_SPINLOCK(die_lock);
259
260/*
261 * This function is protected against re-entrancy.
262 */
263void die(const char *str, struct pt_regs *regs, int err)
264{
265 struct thread_info *thread = current_thread_info();
266 int ret;
267
268 oops_enter();
269
270 spin_lock_irq(&die_lock);
271 console_verbose();
272 bust_spinlocks(1);
273 ret = __die(str, err, thread, regs);
274
275 if (regs && kexec_should_crash(thread->task))
276 crash_kexec(regs);
277
278 bust_spinlocks(0);
279 add_taint(TAINT_DIE);
280 spin_unlock_irq(&die_lock);
281 oops_exit();
282
283 if (in_interrupt())
284 panic("Fatal exception in interrupt");
285 if (panic_on_oops)
286 panic("Fatal exception");
287 if (ret != NOTIFY_STOP)
288 do_exit(SIGSEGV);
289}
290
291void arm_notify_die(const char *str, struct pt_regs *regs,
292 struct siginfo *info, unsigned long err, unsigned long trap)
293{
294 if (user_mode(regs)) {
295 current->thread.error_code = err;
296 current->thread.trap_no = trap;
297
298 force_sig_info(info->si_signo, info, current);
299 } else {
300 die(str, regs, err);
301 }
302}
303
304static LIST_HEAD(undef_hook);
305static DEFINE_SPINLOCK(undef_lock);
306
307void register_undef_hook(struct undef_hook *hook)
308{
309 unsigned long flags;
310
311 spin_lock_irqsave(&undef_lock, flags);
312 list_add(&hook->node, &undef_hook);
313 spin_unlock_irqrestore(&undef_lock, flags);
314}
315
316void unregister_undef_hook(struct undef_hook *hook)
317{
318 unsigned long flags;
319
320 spin_lock_irqsave(&undef_lock, flags);
321 list_del(&hook->node);
322 spin_unlock_irqrestore(&undef_lock, flags);
323}
324
325static int call_undef_hook(struct pt_regs *regs, unsigned int instr)
326{
327 struct undef_hook *hook;
328 unsigned long flags;
329 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL;
330
331 spin_lock_irqsave(&undef_lock, flags);
332 list_for_each_entry(hook, &undef_hook, node)
333 if ((instr & hook->instr_mask) == hook->instr_val &&
334 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val)
335 fn = hook->fn;
336 spin_unlock_irqrestore(&undef_lock, flags);
337
338 return fn ? fn(regs, instr) : 1;
339}
340
341asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
342{
343 unsigned int correction = thumb_mode(regs) ? 2 : 4;
344 unsigned int instr;
345 siginfo_t info;
346 void __user *pc;
347
348 /*
349 * According to the ARM ARM, PC is 2 or 4 bytes ahead,
350 * depending whether we're in Thumb mode or not.
351 * Correct this offset.
352 */
353 regs->ARM_pc -= correction;
354
355 pc = (void __user *)instruction_pointer(regs);
356
357 if (processor_mode(regs) == SVC_MODE) {
358#ifdef CONFIG_THUMB2_KERNEL
359 if (thumb_mode(regs)) {
360 instr = ((u16 *)pc)[0];
361 if (is_wide_instruction(instr)) {
362 instr <<= 16;
363 instr |= ((u16 *)pc)[1];
364 }
365 } else
366#endif
367 instr = *(u32 *) pc;
368 } else if (thumb_mode(regs)) {
369 get_user(instr, (u16 __user *)pc);
370 if (is_wide_instruction(instr)) {
371 unsigned int instr2;
372 get_user(instr2, (u16 __user *)pc+1);
373 instr <<= 16;
374 instr |= instr2;
375 }
376 } else {
377 get_user(instr, (u32 __user *)pc);
378 }
379
380 if (call_undef_hook(regs, instr) == 0)
381 return;
382
383#ifdef CONFIG_DEBUG_USER
384 if (user_debug & UDBG_UNDEFINED) {
385 printk(KERN_INFO "%s (%d): undefined instruction: pc=%p\n",
386 current->comm, task_pid_nr(current), pc);
387 dump_instr(KERN_INFO, regs);
388 }
389#endif
390
391 info.si_signo = SIGILL;
392 info.si_errno = 0;
393 info.si_code = ILL_ILLOPC;
394 info.si_addr = pc;
395
396 arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6);
397}
398
399asmlinkage void do_unexp_fiq (struct pt_regs *regs)
400{
401 printk("Hmm. Unexpected FIQ received, but trying to continue\n");
402 printk("You may have a hardware problem...\n");
403}
404
405/*
406 * bad_mode handles the impossible case in the vectors. If you see one of
407 * these, then it's extremely serious, and could mean you have buggy hardware.
408 * It never returns, and never tries to sync. We hope that we can at least
409 * dump out some state information...
410 */
411asmlinkage void bad_mode(struct pt_regs *regs, int reason)
412{
413 console_verbose();
414
415 printk(KERN_CRIT "Bad mode in %s handler detected\n", handler[reason]);
416
417 die("Oops - bad mode", regs, 0);
418 local_irq_disable();
419 panic("bad mode");
420}
421
422static int bad_syscall(int n, struct pt_regs *regs)
423{
424 struct thread_info *thread = current_thread_info();
425 siginfo_t info;
426
427 if ((current->personality & PER_MASK) != PER_LINUX &&
428 thread->exec_domain->handler) {
429 thread->exec_domain->handler(n, regs);
430 return regs->ARM_r0;
431 }
432
433#ifdef CONFIG_DEBUG_USER
434 if (user_debug & UDBG_SYSCALL) {
435 printk(KERN_ERR "[%d] %s: obsolete system call %08x.\n",
436 task_pid_nr(current), current->comm, n);
437 dump_instr(KERN_ERR, regs);
438 }
439#endif
440
441 info.si_signo = SIGILL;
442 info.si_errno = 0;
443 info.si_code = ILL_ILLTRP;
444 info.si_addr = (void __user *)instruction_pointer(regs) -
445 (thumb_mode(regs) ? 2 : 4);
446
447 arm_notify_die("Oops - bad syscall", regs, &info, n, 0);
448
449 return regs->ARM_r0;
450}
451
452static inline void
453do_cache_op(unsigned long start, unsigned long end, int flags)
454{
455 struct mm_struct *mm = current->active_mm;
456 struct vm_area_struct *vma;
457
458 if (end < start || flags)
459 return;
460
461 down_read(&mm->mmap_sem);
462 vma = find_vma(mm, start);
463 if (vma && vma->vm_start < end) {
464 if (start < vma->vm_start)
465 start = vma->vm_start;
466 if (end > vma->vm_end)
467 end = vma->vm_end;
468
469 flush_cache_user_range(vma, start, end);
470 }
471 up_read(&mm->mmap_sem);
472}
473
474/*
475 * Handle all unrecognised system calls.
476 * 0x9f0000 - 0x9fffff are some more esoteric system calls
477 */
478#define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
479asmlinkage int arm_syscall(int no, struct pt_regs *regs)
480{
481 struct thread_info *thread = current_thread_info();
482 siginfo_t info;
483
484 if ((no >> 16) != (__ARM_NR_BASE>> 16))
485 return bad_syscall(no, regs);
486
487 switch (no & 0xffff) {
488 case 0: /* branch through 0 */
489 info.si_signo = SIGSEGV;
490 info.si_errno = 0;
491 info.si_code = SEGV_MAPERR;
492 info.si_addr = NULL;
493
494 arm_notify_die("branch through zero", regs, &info, 0, 0);
495 return 0;
496
497 case NR(breakpoint): /* SWI BREAK_POINT */
498 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
499 ptrace_break(current, regs);
500 return regs->ARM_r0;
501
502 /*
503 * Flush a region from virtual address 'r0' to virtual address 'r1'
504 * _exclusive_. There is no alignment requirement on either address;
505 * user space does not need to know the hardware cache layout.
506 *
507 * r2 contains flags. It should ALWAYS be passed as ZERO until it
508 * is defined to be something else. For now we ignore it, but may
509 * the fires of hell burn in your belly if you break this rule. ;)
510 *
511 * (at a later date, we may want to allow this call to not flush
512 * various aspects of the cache. Passing '0' will guarantee that
513 * everything necessary gets flushed to maintain consistency in
514 * the specified region).
515 */
516 case NR(cacheflush):
517 do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
518 return 0;
519
520 case NR(usr26):
521 if (!(elf_hwcap & HWCAP_26BIT))
522 break;
523 regs->ARM_cpsr &= ~MODE32_BIT;
524 return regs->ARM_r0;
525
526 case NR(usr32):
527 if (!(elf_hwcap & HWCAP_26BIT))
528 break;
529 regs->ARM_cpsr |= MODE32_BIT;
530 return regs->ARM_r0;
531
532 case NR(set_tls):
533 thread->tp_value = regs->ARM_r0;
534 if (tls_emu)
535 return 0;
536 if (has_tls_reg) {
537 asm ("mcr p15, 0, %0, c13, c0, 3"
538 : : "r" (regs->ARM_r0));
539 } else {
540 /*
541 * User space must never try to access this directly.
542 * Expect your app to break eventually if you do so.
543 * The user helper at 0xffff0fe0 must be used instead.
544 * (see entry-armv.S for details)
545 */
546 *((unsigned int *)0xffff0ff0) = regs->ARM_r0;
547 }
548 return 0;
549
550#ifdef CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG
551 /*
552 * Atomically store r1 in *r2 if *r2 is equal to r0 for user space.
553 * Return zero in r0 if *MEM was changed or non-zero if no exchange
554 * happened. Also set the user C flag accordingly.
555 * If access permissions have to be fixed up then non-zero is
556 * returned and the operation has to be re-attempted.
557 *
558 * *NOTE*: This is a ghost syscall private to the kernel. Only the
559 * __kuser_cmpxchg code in entry-armv.S should be aware of its
560 * existence. Don't ever use this from user code.
561 */
562 case NR(cmpxchg):
563 for (;;) {
564 extern void do_DataAbort(unsigned long addr, unsigned int fsr,
565 struct pt_regs *regs);
566 unsigned long val;
567 unsigned long addr = regs->ARM_r2;
568 struct mm_struct *mm = current->mm;
569 pgd_t *pgd; pmd_t *pmd; pte_t *pte;
570 spinlock_t *ptl;
571
572 regs->ARM_cpsr &= ~PSR_C_BIT;
573 down_read(&mm->mmap_sem);
574 pgd = pgd_offset(mm, addr);
575 if (!pgd_present(*pgd))
576 goto bad_access;
577 pmd = pmd_offset(pgd, addr);
578 if (!pmd_present(*pmd))
579 goto bad_access;
580 pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
581 if (!pte_present(*pte) || !pte_write(*pte) || !pte_dirty(*pte)) {
582 pte_unmap_unlock(pte, ptl);
583 goto bad_access;
584 }
585 val = *(unsigned long *)addr;
586 val -= regs->ARM_r0;
587 if (val == 0) {
588 *(unsigned long *)addr = regs->ARM_r1;
589 regs->ARM_cpsr |= PSR_C_BIT;
590 }
591 pte_unmap_unlock(pte, ptl);
592 up_read(&mm->mmap_sem);
593 return val;
594
595 bad_access:
596 up_read(&mm->mmap_sem);
597 /* simulate a write access fault */
598 do_DataAbort(addr, 15 + (1 << 11), regs);
599 }
600#endif
601
602 default:
603 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS
604 if not implemented, rather than raising SIGILL. This
605 way the calling program can gracefully determine whether
606 a feature is supported. */
607 if ((no & 0xffff) <= 0x7ff)
608 return -ENOSYS;
609 break;
610 }
611#ifdef CONFIG_DEBUG_USER
612 /*
613 * experience shows that these seem to indicate that
614 * something catastrophic has happened
615 */
616 if (user_debug & UDBG_SYSCALL) {
617 printk("[%d] %s: arm syscall %d\n",
618 task_pid_nr(current), current->comm, no);
619 dump_instr("", regs);
620 if (user_mode(regs)) {
621 __show_regs(regs);
622 c_backtrace(regs->ARM_fp, processor_mode(regs));
623 }
624 }
625#endif
626 info.si_signo = SIGILL;
627 info.si_errno = 0;
628 info.si_code = ILL_ILLTRP;
629 info.si_addr = (void __user *)instruction_pointer(regs) -
630 (thumb_mode(regs) ? 2 : 4);
631
632 arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0);
633 return 0;
634}
635
636#ifdef CONFIG_TLS_REG_EMUL
637
638/*
639 * We might be running on an ARMv6+ processor which should have the TLS
640 * register but for some reason we can't use it, or maybe an SMP system
641 * using a pre-ARMv6 processor (there are apparently a few prototypes like
642 * that in existence) and therefore access to that register must be
643 * emulated.
644 */
645
646static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
647{
648 int reg = (instr >> 12) & 15;
649 if (reg == 15)
650 return 1;
651 regs->uregs[reg] = current_thread_info()->tp_value;
652 regs->ARM_pc += 4;
653 return 0;
654}
655
656static struct undef_hook arm_mrc_hook = {
657 .instr_mask = 0x0fff0fff,
658 .instr_val = 0x0e1d0f70,
659 .cpsr_mask = PSR_T_BIT,
660 .cpsr_val = 0,
661 .fn = get_tp_trap,
662};
663
664static int __init arm_mrc_hook_init(void)
665{
666 register_undef_hook(&arm_mrc_hook);
667 return 0;
668}
669
670late_initcall(arm_mrc_hook_init);
671
672#endif
673
674void __bad_xchg(volatile void *ptr, int size)
675{
676 printk("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n",
677 __builtin_return_address(0), ptr, size);
678 BUG();
679}
680EXPORT_SYMBOL(__bad_xchg);
681
682/*
683 * A data abort trap was taken, but we did not handle the instruction.
684 * Try to abort the user program, or panic if it was the kernel.
685 */
686asmlinkage void
687baddataabort(int code, unsigned long instr, struct pt_regs *regs)
688{
689 unsigned long addr = instruction_pointer(regs);
690 siginfo_t info;
691
692#ifdef CONFIG_DEBUG_USER
693 if (user_debug & UDBG_BADABORT) {
694 printk(KERN_ERR "[%d] %s: bad data abort: code %d instr 0x%08lx\n",
695 task_pid_nr(current), current->comm, code, instr);
696 dump_instr(KERN_ERR, regs);
697 show_pte(current->mm, addr);
698 }
699#endif
700
701 info.si_signo = SIGILL;
702 info.si_errno = 0;
703 info.si_code = ILL_ILLOPC;
704 info.si_addr = (void __user *)addr;
705
706 arm_notify_die("unknown data abort code", regs, &info, instr, 0);
707}
708
709void __attribute__((noreturn)) __bug(const char *file, int line)
710{
711 printk(KERN_CRIT"kernel BUG at %s:%d!\n", file, line);
712 *(int *)0 = 0;
713
714 /* Avoid "noreturn function does return" */
715 for (;;);
716}
717EXPORT_SYMBOL(__bug);
718
719void __readwrite_bug(const char *fn)
720{
721 printk("%s called, but not implemented\n", fn);
722 BUG();
723}
724EXPORT_SYMBOL(__readwrite_bug);
725
726void __pte_error(const char *file, int line, pte_t pte)
727{
728 printk("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte));
729}
730
731void __pmd_error(const char *file, int line, pmd_t pmd)
732{
733 printk("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd));
734}
735
736void __pgd_error(const char *file, int line, pgd_t pgd)
737{
738 printk("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd));
739}
740
741asmlinkage void __div0(void)
742{
743 printk("Division by zero in kernel.\n");
744 dump_stack();
745}
746EXPORT_SYMBOL(__div0);
747
748void abort(void)
749{
750 BUG();
751
752 /* if that doesn't kill us, halt */
753 panic("Oops failed to kill thread");
754}
755EXPORT_SYMBOL(abort);
756
757void __init trap_init(void)
758{
759 return;
760}
761
762static void __init kuser_get_tls_init(unsigned long vectors)
763{
764 /*
765 * vectors + 0xfe0 = __kuser_get_tls
766 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8
767 */
768 if (tls_emu || has_tls_reg)
769 memcpy((void *)vectors + 0xfe0, (void *)vectors + 0xfe8, 4);
770}
771
772void __init early_trap_init(void)
773{
774#if defined(CONFIG_CPU_USE_DOMAINS)
775 unsigned long vectors = CONFIG_VECTORS_BASE;
776#else
777 unsigned long vectors = (unsigned long)vectors_page;
778#endif
779 extern char __stubs_start[], __stubs_end[];
780 extern char __vectors_start[], __vectors_end[];
781 extern char __kuser_helper_start[], __kuser_helper_end[];
782 int kuser_sz = __kuser_helper_end - __kuser_helper_start;
783
784 /*
785 * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
786 * into the vector page, mapped at 0xffff0000, and ensure these
787 * are visible to the instruction stream.
788 */
789 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
790 memcpy((void *)vectors + 0x200, __stubs_start, __stubs_end - __stubs_start);
791 memcpy((void *)vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
792
793 /*
794 * Do processor specific fixups for the kuser helpers
795 */
796 kuser_get_tls_init(vectors);
797
798 /*
799 * Copy signal return handlers into the vector page, and
800 * set sigreturn to be a pointer to these.
801 */
802 memcpy((void *)(vectors + KERN_SIGRETURN_CODE - CONFIG_VECTORS_BASE),
803 sigreturn_codes, sizeof(sigreturn_codes));
804 memcpy((void *)(vectors + KERN_RESTART_CODE - CONFIG_VECTORS_BASE),
805 syscall_restart_code, sizeof(syscall_restart_code));
806
807 flush_icache_range(vectors, vectors + PAGE_SIZE);
808 modify_domain(DOMAIN_USER, DOMAIN_CLIENT);
809}
1/*
2 * linux/arch/arm/kernel/traps.c
3 *
4 * Copyright (C) 1995-2009 Russell King
5 * Fragments that appear the same as linux/arch/i386/kernel/traps.c (C) Linus Torvalds
6 *
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.
10 *
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.
14 */
15#include <linux/signal.h>
16#include <linux/personality.h>
17#include <linux/kallsyms.h>
18#include <linux/spinlock.h>
19#include <linux/uaccess.h>
20#include <linux/hardirq.h>
21#include <linux/kdebug.h>
22#include <linux/module.h>
23#include <linux/kexec.h>
24#include <linux/bug.h>
25#include <linux/delay.h>
26#include <linux/init.h>
27#include <linux/sched.h>
28#include <linux/irq.h>
29
30#include <linux/atomic.h>
31#include <asm/cacheflush.h>
32#include <asm/exception.h>
33#include <asm/unistd.h>
34#include <asm/traps.h>
35#include <asm/ptrace.h>
36#include <asm/unwind.h>
37#include <asm/tls.h>
38#include <asm/system_misc.h>
39#include <asm/opcodes.h>
40
41
42static const char *handler[]= {
43 "prefetch abort",
44 "data abort",
45 "address exception",
46 "interrupt",
47 "undefined instruction",
48};
49
50void *vectors_page;
51
52#ifdef CONFIG_DEBUG_USER
53unsigned int user_debug;
54
55static int __init user_debug_setup(char *str)
56{
57 get_option(&str, &user_debug);
58 return 1;
59}
60__setup("user_debug=", user_debug_setup);
61#endif
62
63static void dump_mem(const char *, const char *, unsigned long, unsigned long);
64
65void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame)
66{
67#ifdef CONFIG_KALLSYMS
68 printk("[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from);
69#else
70 printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
71#endif
72
73 if (in_exception_text(where))
74 dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs));
75}
76
77void dump_backtrace_stm(u32 *stack, u32 instruction)
78{
79 char str[80], *p;
80 unsigned int x;
81 int reg;
82
83 for (reg = 10, x = 0, p = str; reg >= 0; reg--) {
84 if (instruction & BIT(reg)) {
85 p += sprintf(p, " r%d:%08x", reg, *stack--);
86 if (++x == 6) {
87 x = 0;
88 p = str;
89 printk("%s\n", str);
90 }
91 }
92 }
93 if (p != str)
94 printk("%s\n", str);
95}
96
97#ifndef CONFIG_ARM_UNWIND
98/*
99 * Stack pointers should always be within the kernels view of
100 * physical memory. If it is not there, then we can't dump
101 * out any information relating to the stack.
102 */
103static int verify_stack(unsigned long sp)
104{
105 if (sp < PAGE_OFFSET ||
106 (sp > (unsigned long)high_memory && high_memory != NULL))
107 return -EFAULT;
108
109 return 0;
110}
111#endif
112
113/*
114 * Dump out the contents of some memory nicely...
115 */
116static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
117 unsigned long top)
118{
119 unsigned long first;
120 mm_segment_t fs;
121 int i;
122
123 /*
124 * We need to switch to kernel mode so that we can use __get_user
125 * to safely read from kernel space. Note that we now dump the
126 * code first, just in case the backtrace kills us.
127 */
128 fs = get_fs();
129 set_fs(KERNEL_DS);
130
131 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top);
132
133 for (first = bottom & ~31; first < top; first += 32) {
134 unsigned long p;
135 char str[sizeof(" 12345678") * 8 + 1];
136
137 memset(str, ' ', sizeof(str));
138 str[sizeof(str) - 1] = '\0';
139
140 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
141 if (p >= bottom && p < top) {
142 unsigned long val;
143 if (__get_user(val, (unsigned long *)p) == 0)
144 sprintf(str + i * 9, " %08lx", val);
145 else
146 sprintf(str + i * 9, " ????????");
147 }
148 }
149 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
150 }
151
152 set_fs(fs);
153}
154
155static void dump_instr(const char *lvl, struct pt_regs *regs)
156{
157 unsigned long addr = instruction_pointer(regs);
158 const int thumb = thumb_mode(regs);
159 const int width = thumb ? 4 : 8;
160 mm_segment_t fs;
161 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
162 int i;
163
164 /*
165 * We need to switch to kernel mode so that we can use __get_user
166 * to safely read from kernel space. Note that we now dump the
167 * code first, just in case the backtrace kills us.
168 */
169 fs = get_fs();
170 set_fs(KERNEL_DS);
171
172 for (i = -4; i < 1 + !!thumb; i++) {
173 unsigned int val, bad;
174
175 if (thumb)
176 bad = __get_user(val, &((u16 *)addr)[i]);
177 else
178 bad = __get_user(val, &((u32 *)addr)[i]);
179
180 if (!bad)
181 p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ",
182 width, val);
183 else {
184 p += sprintf(p, "bad PC value");
185 break;
186 }
187 }
188 printk("%sCode: %s\n", lvl, str);
189
190 set_fs(fs);
191}
192
193#ifdef CONFIG_ARM_UNWIND
194static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
195{
196 unwind_backtrace(regs, tsk);
197}
198#else
199static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
200{
201 unsigned int fp, mode;
202 int ok = 1;
203
204 printk("Backtrace: ");
205
206 if (!tsk)
207 tsk = current;
208
209 if (regs) {
210 fp = frame_pointer(regs);
211 mode = processor_mode(regs);
212 } else if (tsk != current) {
213 fp = thread_saved_fp(tsk);
214 mode = 0x10;
215 } else {
216 asm("mov %0, fp" : "=r" (fp) : : "cc");
217 mode = 0x10;
218 }
219
220 if (!fp) {
221 pr_cont("no frame pointer");
222 ok = 0;
223 } else if (verify_stack(fp)) {
224 pr_cont("invalid frame pointer 0x%08x", fp);
225 ok = 0;
226 } else if (fp < (unsigned long)end_of_stack(tsk))
227 pr_cont("frame pointer underflow");
228 pr_cont("\n");
229
230 if (ok)
231 c_backtrace(fp, mode);
232}
233#endif
234
235void show_stack(struct task_struct *tsk, unsigned long *sp)
236{
237 dump_backtrace(NULL, tsk);
238 barrier();
239}
240
241#ifdef CONFIG_PREEMPT
242#define S_PREEMPT " PREEMPT"
243#else
244#define S_PREEMPT ""
245#endif
246#ifdef CONFIG_SMP
247#define S_SMP " SMP"
248#else
249#define S_SMP ""
250#endif
251#ifdef CONFIG_THUMB2_KERNEL
252#define S_ISA " THUMB2"
253#else
254#define S_ISA " ARM"
255#endif
256
257static int __die(const char *str, int err, struct pt_regs *regs)
258{
259 struct task_struct *tsk = current;
260 static int die_counter;
261 int ret;
262
263 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP S_ISA "\n",
264 str, err, ++die_counter);
265
266 /* trap and error numbers are mostly meaningless on ARM */
267 ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV);
268 if (ret == NOTIFY_STOP)
269 return 1;
270
271 print_modules();
272 __show_regs(regs);
273 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
274 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk));
275
276 if (!user_mode(regs) || in_interrupt()) {
277 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp,
278 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
279 dump_backtrace(regs, tsk);
280 dump_instr(KERN_EMERG, regs);
281 }
282
283 return 0;
284}
285
286static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
287static int die_owner = -1;
288static unsigned int die_nest_count;
289
290static unsigned long oops_begin(void)
291{
292 int cpu;
293 unsigned long flags;
294
295 oops_enter();
296
297 /* racy, but better than risking deadlock. */
298 raw_local_irq_save(flags);
299 cpu = smp_processor_id();
300 if (!arch_spin_trylock(&die_lock)) {
301 if (cpu == die_owner)
302 /* nested oops. should stop eventually */;
303 else
304 arch_spin_lock(&die_lock);
305 }
306 die_nest_count++;
307 die_owner = cpu;
308 console_verbose();
309 bust_spinlocks(1);
310 return flags;
311}
312
313static void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
314{
315 if (regs && kexec_should_crash(current))
316 crash_kexec(regs);
317
318 bust_spinlocks(0);
319 die_owner = -1;
320 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
321 die_nest_count--;
322 if (!die_nest_count)
323 /* Nest count reaches zero, release the lock. */
324 arch_spin_unlock(&die_lock);
325 raw_local_irq_restore(flags);
326 oops_exit();
327
328 if (in_interrupt())
329 panic("Fatal exception in interrupt");
330 if (panic_on_oops)
331 panic("Fatal exception");
332 if (signr)
333 do_exit(signr);
334}
335
336/*
337 * This function is protected against re-entrancy.
338 */
339void die(const char *str, struct pt_regs *regs, int err)
340{
341 enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE;
342 unsigned long flags = oops_begin();
343 int sig = SIGSEGV;
344
345 if (!user_mode(regs))
346 bug_type = report_bug(regs->ARM_pc, regs);
347 if (bug_type != BUG_TRAP_TYPE_NONE)
348 str = "Oops - BUG";
349
350 if (__die(str, err, regs))
351 sig = 0;
352
353 oops_end(flags, regs, sig);
354}
355
356void arm_notify_die(const char *str, struct pt_regs *regs,
357 struct siginfo *info, unsigned long err, unsigned long trap)
358{
359 if (user_mode(regs)) {
360 current->thread.error_code = err;
361 current->thread.trap_no = trap;
362
363 force_sig_info(info->si_signo, info, current);
364 } else {
365 die(str, regs, err);
366 }
367}
368
369#ifdef CONFIG_GENERIC_BUG
370
371int is_valid_bugaddr(unsigned long pc)
372{
373#ifdef CONFIG_THUMB2_KERNEL
374 u16 bkpt;
375 u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE);
376#else
377 u32 bkpt;
378 u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE);
379#endif
380
381 if (probe_kernel_address((unsigned *)pc, bkpt))
382 return 0;
383
384 return bkpt == insn;
385}
386
387#endif
388
389static LIST_HEAD(undef_hook);
390static DEFINE_RAW_SPINLOCK(undef_lock);
391
392void register_undef_hook(struct undef_hook *hook)
393{
394 unsigned long flags;
395
396 raw_spin_lock_irqsave(&undef_lock, flags);
397 list_add(&hook->node, &undef_hook);
398 raw_spin_unlock_irqrestore(&undef_lock, flags);
399}
400
401void unregister_undef_hook(struct undef_hook *hook)
402{
403 unsigned long flags;
404
405 raw_spin_lock_irqsave(&undef_lock, flags);
406 list_del(&hook->node);
407 raw_spin_unlock_irqrestore(&undef_lock, flags);
408}
409
410static int call_undef_hook(struct pt_regs *regs, unsigned int instr)
411{
412 struct undef_hook *hook;
413 unsigned long flags;
414 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL;
415
416 raw_spin_lock_irqsave(&undef_lock, flags);
417 list_for_each_entry(hook, &undef_hook, node)
418 if ((instr & hook->instr_mask) == hook->instr_val &&
419 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val)
420 fn = hook->fn;
421 raw_spin_unlock_irqrestore(&undef_lock, flags);
422
423 return fn ? fn(regs, instr) : 1;
424}
425
426asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
427{
428 unsigned int instr;
429 siginfo_t info;
430 void __user *pc;
431
432 pc = (void __user *)instruction_pointer(regs);
433
434 if (processor_mode(regs) == SVC_MODE) {
435#ifdef CONFIG_THUMB2_KERNEL
436 if (thumb_mode(regs)) {
437 instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]);
438 if (is_wide_instruction(instr)) {
439 u16 inst2;
440 inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]);
441 instr = __opcode_thumb32_compose(instr, inst2);
442 }
443 } else
444#endif
445 instr = __mem_to_opcode_arm(*(u32 *) pc);
446 } else if (thumb_mode(regs)) {
447 if (get_user(instr, (u16 __user *)pc))
448 goto die_sig;
449 instr = __mem_to_opcode_thumb16(instr);
450 if (is_wide_instruction(instr)) {
451 unsigned int instr2;
452 if (get_user(instr2, (u16 __user *)pc+1))
453 goto die_sig;
454 instr2 = __mem_to_opcode_thumb16(instr2);
455 instr = __opcode_thumb32_compose(instr, instr2);
456 }
457 } else {
458 if (get_user(instr, (u32 __user *)pc))
459 goto die_sig;
460 instr = __mem_to_opcode_arm(instr);
461 }
462
463 if (call_undef_hook(regs, instr) == 0)
464 return;
465
466die_sig:
467#ifdef CONFIG_DEBUG_USER
468 if (user_debug & UDBG_UNDEFINED) {
469 pr_info("%s (%d): undefined instruction: pc=%p\n",
470 current->comm, task_pid_nr(current), pc);
471 __show_regs(regs);
472 dump_instr(KERN_INFO, regs);
473 }
474#endif
475
476 info.si_signo = SIGILL;
477 info.si_errno = 0;
478 info.si_code = ILL_ILLOPC;
479 info.si_addr = pc;
480
481 arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6);
482}
483
484/*
485 * Handle FIQ similarly to NMI on x86 systems.
486 *
487 * The runtime environment for NMIs is extremely restrictive
488 * (NMIs can pre-empt critical sections meaning almost all locking is
489 * forbidden) meaning this default FIQ handling must only be used in
490 * circumstances where non-maskability improves robustness, such as
491 * watchdog or debug logic.
492 *
493 * This handler is not appropriate for general purpose use in drivers
494 * platform code and can be overrideen using set_fiq_handler.
495 */
496asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs)
497{
498 struct pt_regs *old_regs = set_irq_regs(regs);
499
500 nmi_enter();
501
502 /* nop. FIQ handlers for special arch/arm features can be added here. */
503
504 nmi_exit();
505
506 set_irq_regs(old_regs);
507}
508
509/*
510 * bad_mode handles the impossible case in the vectors. If you see one of
511 * these, then it's extremely serious, and could mean you have buggy hardware.
512 * It never returns, and never tries to sync. We hope that we can at least
513 * dump out some state information...
514 */
515asmlinkage void bad_mode(struct pt_regs *regs, int reason)
516{
517 console_verbose();
518
519 pr_crit("Bad mode in %s handler detected\n", handler[reason]);
520
521 die("Oops - bad mode", regs, 0);
522 local_irq_disable();
523 panic("bad mode");
524}
525
526static int bad_syscall(int n, struct pt_regs *regs)
527{
528 siginfo_t info;
529
530 if ((current->personality & PER_MASK) != PER_LINUX) {
531 send_sig(SIGSEGV, current, 1);
532 return regs->ARM_r0;
533 }
534
535#ifdef CONFIG_DEBUG_USER
536 if (user_debug & UDBG_SYSCALL) {
537 pr_err("[%d] %s: obsolete system call %08x.\n",
538 task_pid_nr(current), current->comm, n);
539 dump_instr(KERN_ERR, regs);
540 }
541#endif
542
543 info.si_signo = SIGILL;
544 info.si_errno = 0;
545 info.si_code = ILL_ILLTRP;
546 info.si_addr = (void __user *)instruction_pointer(regs) -
547 (thumb_mode(regs) ? 2 : 4);
548
549 arm_notify_die("Oops - bad syscall", regs, &info, n, 0);
550
551 return regs->ARM_r0;
552}
553
554static inline int
555__do_cache_op(unsigned long start, unsigned long end)
556{
557 int ret;
558
559 do {
560 unsigned long chunk = min(PAGE_SIZE, end - start);
561
562 if (fatal_signal_pending(current))
563 return 0;
564
565 ret = flush_cache_user_range(start, start + chunk);
566 if (ret)
567 return ret;
568
569 cond_resched();
570 start += chunk;
571 } while (start < end);
572
573 return 0;
574}
575
576static inline int
577do_cache_op(unsigned long start, unsigned long end, int flags)
578{
579 if (end < start || flags)
580 return -EINVAL;
581
582 if (!access_ok(VERIFY_READ, start, end - start))
583 return -EFAULT;
584
585 return __do_cache_op(start, end);
586}
587
588/*
589 * Handle all unrecognised system calls.
590 * 0x9f0000 - 0x9fffff are some more esoteric system calls
591 */
592#define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
593asmlinkage int arm_syscall(int no, struct pt_regs *regs)
594{
595 siginfo_t info;
596
597 if ((no >> 16) != (__ARM_NR_BASE>> 16))
598 return bad_syscall(no, regs);
599
600 switch (no & 0xffff) {
601 case 0: /* branch through 0 */
602 info.si_signo = SIGSEGV;
603 info.si_errno = 0;
604 info.si_code = SEGV_MAPERR;
605 info.si_addr = NULL;
606
607 arm_notify_die("branch through zero", regs, &info, 0, 0);
608 return 0;
609
610 case NR(breakpoint): /* SWI BREAK_POINT */
611 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
612 ptrace_break(current, regs);
613 return regs->ARM_r0;
614
615 /*
616 * Flush a region from virtual address 'r0' to virtual address 'r1'
617 * _exclusive_. There is no alignment requirement on either address;
618 * user space does not need to know the hardware cache layout.
619 *
620 * r2 contains flags. It should ALWAYS be passed as ZERO until it
621 * is defined to be something else. For now we ignore it, but may
622 * the fires of hell burn in your belly if you break this rule. ;)
623 *
624 * (at a later date, we may want to allow this call to not flush
625 * various aspects of the cache. Passing '0' will guarantee that
626 * everything necessary gets flushed to maintain consistency in
627 * the specified region).
628 */
629 case NR(cacheflush):
630 return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
631
632 case NR(usr26):
633 if (!(elf_hwcap & HWCAP_26BIT))
634 break;
635 regs->ARM_cpsr &= ~MODE32_BIT;
636 return regs->ARM_r0;
637
638 case NR(usr32):
639 if (!(elf_hwcap & HWCAP_26BIT))
640 break;
641 regs->ARM_cpsr |= MODE32_BIT;
642 return regs->ARM_r0;
643
644 case NR(set_tls):
645 set_tls(regs->ARM_r0);
646 return 0;
647
648 default:
649 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS
650 if not implemented, rather than raising SIGILL. This
651 way the calling program can gracefully determine whether
652 a feature is supported. */
653 if ((no & 0xffff) <= 0x7ff)
654 return -ENOSYS;
655 break;
656 }
657#ifdef CONFIG_DEBUG_USER
658 /*
659 * experience shows that these seem to indicate that
660 * something catastrophic has happened
661 */
662 if (user_debug & UDBG_SYSCALL) {
663 pr_err("[%d] %s: arm syscall %d\n",
664 task_pid_nr(current), current->comm, no);
665 dump_instr("", regs);
666 if (user_mode(regs)) {
667 __show_regs(regs);
668 c_backtrace(frame_pointer(regs), processor_mode(regs));
669 }
670 }
671#endif
672 info.si_signo = SIGILL;
673 info.si_errno = 0;
674 info.si_code = ILL_ILLTRP;
675 info.si_addr = (void __user *)instruction_pointer(regs) -
676 (thumb_mode(regs) ? 2 : 4);
677
678 arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0);
679 return 0;
680}
681
682#ifdef CONFIG_TLS_REG_EMUL
683
684/*
685 * We might be running on an ARMv6+ processor which should have the TLS
686 * register but for some reason we can't use it, or maybe an SMP system
687 * using a pre-ARMv6 processor (there are apparently a few prototypes like
688 * that in existence) and therefore access to that register must be
689 * emulated.
690 */
691
692static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
693{
694 int reg = (instr >> 12) & 15;
695 if (reg == 15)
696 return 1;
697 regs->uregs[reg] = current_thread_info()->tp_value[0];
698 regs->ARM_pc += 4;
699 return 0;
700}
701
702static struct undef_hook arm_mrc_hook = {
703 .instr_mask = 0x0fff0fff,
704 .instr_val = 0x0e1d0f70,
705 .cpsr_mask = PSR_T_BIT,
706 .cpsr_val = 0,
707 .fn = get_tp_trap,
708};
709
710static int __init arm_mrc_hook_init(void)
711{
712 register_undef_hook(&arm_mrc_hook);
713 return 0;
714}
715
716late_initcall(arm_mrc_hook_init);
717
718#endif
719
720/*
721 * A data abort trap was taken, but we did not handle the instruction.
722 * Try to abort the user program, or panic if it was the kernel.
723 */
724asmlinkage void
725baddataabort(int code, unsigned long instr, struct pt_regs *regs)
726{
727 unsigned long addr = instruction_pointer(regs);
728 siginfo_t info;
729
730#ifdef CONFIG_DEBUG_USER
731 if (user_debug & UDBG_BADABORT) {
732 pr_err("[%d] %s: bad data abort: code %d instr 0x%08lx\n",
733 task_pid_nr(current), current->comm, code, instr);
734 dump_instr(KERN_ERR, regs);
735 show_pte(current->mm, addr);
736 }
737#endif
738
739 info.si_signo = SIGILL;
740 info.si_errno = 0;
741 info.si_code = ILL_ILLOPC;
742 info.si_addr = (void __user *)addr;
743
744 arm_notify_die("unknown data abort code", regs, &info, instr, 0);
745}
746
747void __readwrite_bug(const char *fn)
748{
749 pr_err("%s called, but not implemented\n", fn);
750 BUG();
751}
752EXPORT_SYMBOL(__readwrite_bug);
753
754void __pte_error(const char *file, int line, pte_t pte)
755{
756 pr_err("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte));
757}
758
759void __pmd_error(const char *file, int line, pmd_t pmd)
760{
761 pr_err("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd));
762}
763
764void __pgd_error(const char *file, int line, pgd_t pgd)
765{
766 pr_err("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd));
767}
768
769asmlinkage void __div0(void)
770{
771 pr_err("Division by zero in kernel.\n");
772 dump_stack();
773}
774EXPORT_SYMBOL(__div0);
775
776void abort(void)
777{
778 BUG();
779
780 /* if that doesn't kill us, halt */
781 panic("Oops failed to kill thread");
782}
783EXPORT_SYMBOL(abort);
784
785void __init trap_init(void)
786{
787 return;
788}
789
790#ifdef CONFIG_KUSER_HELPERS
791static void __init kuser_init(void *vectors)
792{
793 extern char __kuser_helper_start[], __kuser_helper_end[];
794 int kuser_sz = __kuser_helper_end - __kuser_helper_start;
795
796 memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
797
798 /*
799 * vectors + 0xfe0 = __kuser_get_tls
800 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8
801 */
802 if (tls_emu || has_tls_reg)
803 memcpy(vectors + 0xfe0, vectors + 0xfe8, 4);
804}
805#else
806static inline void __init kuser_init(void *vectors)
807{
808}
809#endif
810
811void __init early_trap_init(void *vectors_base)
812{
813#ifndef CONFIG_CPU_V7M
814 unsigned long vectors = (unsigned long)vectors_base;
815 extern char __stubs_start[], __stubs_end[];
816 extern char __vectors_start[], __vectors_end[];
817 unsigned i;
818
819 vectors_page = vectors_base;
820
821 /*
822 * Poison the vectors page with an undefined instruction. This
823 * instruction is chosen to be undefined for both ARM and Thumb
824 * ISAs. The Thumb version is an undefined instruction with a
825 * branch back to the undefined instruction.
826 */
827 for (i = 0; i < PAGE_SIZE / sizeof(u32); i++)
828 ((u32 *)vectors_base)[i] = 0xe7fddef1;
829
830 /*
831 * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
832 * into the vector page, mapped at 0xffff0000, and ensure these
833 * are visible to the instruction stream.
834 */
835 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
836 memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start);
837
838 kuser_init(vectors_base);
839
840 flush_icache_range(vectors, vectors + PAGE_SIZE * 2);
841#else /* ifndef CONFIG_CPU_V7M */
842 /*
843 * on V7-M there is no need to copy the vector table to a dedicated
844 * memory area. The address is configurable and so a table in the kernel
845 * image can be used.
846 */
847#endif
848}