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