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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
27#include <asm/atomic.h>
28#include <asm/cacheflush.h>
29#include <asm/system.h>
30#include <asm/unistd.h>
31#include <asm/traps.h>
32#include <asm/unwind.h>
33#include <asm/tls.h>
34
35#include "ptrace.h"
36#include "signal.h"
37
38static const char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" };
39
40#ifdef CONFIG_DEBUG_USER
41unsigned int user_debug;
42
43static int __init user_debug_setup(char *str)
44{
45	get_option(&str, &user_debug);
46	return 1;
47}
48__setup("user_debug=", user_debug_setup);
49#endif
50
51static void dump_mem(const char *, const char *, unsigned long, unsigned long);
52
53void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame)
54{
55#ifdef CONFIG_KALLSYMS
56	char sym1[KSYM_SYMBOL_LEN], sym2[KSYM_SYMBOL_LEN];
57	sprint_symbol(sym1, where);
58	sprint_symbol(sym2, from);
59	printk("[<%08lx>] (%s) from [<%08lx>] (%s)\n", where, sym1, from, sym2);
60#else
61	printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
62#endif
63
64	if (in_exception_text(where))
65		dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs));
66}
67
68#ifndef CONFIG_ARM_UNWIND
69/*
70 * Stack pointers should always be within the kernels view of
71 * physical memory.  If it is not there, then we can't dump
72 * out any information relating to the stack.
73 */
74static int verify_stack(unsigned long sp)
75{
76	if (sp < PAGE_OFFSET ||
77	    (sp > (unsigned long)high_memory && high_memory != NULL))
78		return -EFAULT;
79
80	return 0;
81}
82#endif
83
84/*
85 * Dump out the contents of some memory nicely...
86 */
87static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
88		     unsigned long top)
89{
90	unsigned long first;
91	mm_segment_t fs;
92	int i;
93
94	/*
95	 * We need to switch to kernel mode so that we can use __get_user
96	 * to safely read from kernel space.  Note that we now dump the
97	 * code first, just in case the backtrace kills us.
98	 */
99	fs = get_fs();
100	set_fs(KERNEL_DS);
101
102	printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top);
103
104	for (first = bottom & ~31; first < top; first += 32) {
105		unsigned long p;
106		char str[sizeof(" 12345678") * 8 + 1];
107
108		memset(str, ' ', sizeof(str));
109		str[sizeof(str) - 1] = '\0';
110
111		for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
112			if (p >= bottom && p < top) {
113				unsigned long val;
114				if (__get_user(val, (unsigned long *)p) == 0)
115					sprintf(str + i * 9, " %08lx", val);
116				else
117					sprintf(str + i * 9, " ????????");
118			}
119		}
120		printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
121	}
122
123	set_fs(fs);
124}
125
126static void dump_instr(const char *lvl, struct pt_regs *regs)
127{
128	unsigned long addr = instruction_pointer(regs);
129	const int thumb = thumb_mode(regs);
130	const int width = thumb ? 4 : 8;
131	mm_segment_t fs;
132	char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
133	int i;
134
135	/*
136	 * We need to switch to kernel mode so that we can use __get_user
137	 * to safely read from kernel space.  Note that we now dump the
138	 * code first, just in case the backtrace kills us.
139	 */
140	fs = get_fs();
141	set_fs(KERNEL_DS);
142
143	for (i = -4; i < 1; i++) {
144		unsigned int val, bad;
145
146		if (thumb)
147			bad = __get_user(val, &((u16 *)addr)[i]);
148		else
149			bad = __get_user(val, &((u32 *)addr)[i]);
150
151		if (!bad)
152			p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ",
153					width, val);
154		else {
155			p += sprintf(p, "bad PC value");
156			break;
157		}
158	}
159	printk("%sCode: %s\n", lvl, str);
160
161	set_fs(fs);
162}
163
164#ifdef CONFIG_ARM_UNWIND
165static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
166{
167	unwind_backtrace(regs, tsk);
168}
169#else
170static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
171{
172	unsigned int fp, mode;
173	int ok = 1;
174
175	printk("Backtrace: ");
176
177	if (!tsk)
178		tsk = current;
179
180	if (regs) {
181		fp = regs->ARM_fp;
182		mode = processor_mode(regs);
183	} else if (tsk != current) {
184		fp = thread_saved_fp(tsk);
185		mode = 0x10;
186	} else {
187		asm("mov %0, fp" : "=r" (fp) : : "cc");
188		mode = 0x10;
189	}
190
191	if (!fp) {
192		printk("no frame pointer");
193		ok = 0;
194	} else if (verify_stack(fp)) {
195		printk("invalid frame pointer 0x%08x", fp);
196		ok = 0;
197	} else if (fp < (unsigned long)end_of_stack(tsk))
198		printk("frame pointer underflow");
199	printk("\n");
200
201	if (ok)
202		c_backtrace(fp, mode);
203}
204#endif
205
206void dump_stack(void)
207{
208	dump_backtrace(NULL, NULL);
209}
210
211EXPORT_SYMBOL(dump_stack);
212
213void show_stack(struct task_struct *tsk, unsigned long *sp)
214{
215	dump_backtrace(NULL, tsk);
216	barrier();
217}
218
219#ifdef CONFIG_PREEMPT
220#define S_PREEMPT " PREEMPT"
221#else
222#define S_PREEMPT ""
223#endif
224#ifdef CONFIG_SMP
225#define S_SMP " SMP"
226#else
227#define S_SMP ""
228#endif
229
230static int __die(const char *str, int err, struct thread_info *thread, struct pt_regs *regs)
231{
232	struct task_struct *tsk = thread->task;
233	static int die_counter;
234	int ret;
235
236	printk(KERN_EMERG "Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
237	       str, err, ++die_counter);
238	sysfs_printk_last_file();
239
240	/* trap and error numbers are mostly meaningless on ARM */
241	ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV);
242	if (ret == NOTIFY_STOP)
243		return ret;
244
245	print_modules();
246	__show_regs(regs);
247	printk(KERN_EMERG "Process %.*s (pid: %d, stack limit = 0x%p)\n",
248		TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1);
249
250	if (!user_mode(regs) || in_interrupt()) {
251		dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp,
252			 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
253
254		/* Show PC value again for GDB source code trace dump */
255		printk("[<%08lx>] ",regs->ARM_pc);
256		print_symbol("(PC is at %s)\n", instruction_pointer(regs));
257
258		dump_backtrace(regs, tsk);
259		dump_instr(KERN_EMERG, regs);
260	}
261
262	return ret;
263}
264
265DEFINE_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
275	oops_enter();
276
277	spin_lock_irq(&die_lock);
278	console_verbose();
279	bust_spinlocks(1);
280	ret = __die(str, err, thread, regs);
281
282	if (regs && kexec_should_crash(thread->task))
283		crash_kexec(regs);
284
285	bust_spinlocks(0);
286	add_taint(TAINT_DIE);
287	spin_unlock_irq(&die_lock);
288	oops_exit();
289
290	if (in_interrupt())
291		panic("Fatal exception in interrupt");
292	if (panic_on_oops)
293		panic("Fatal exception");
294	if (ret != NOTIFY_STOP)
295		do_exit(SIGSEGV);
296}
297
298void arm_notify_die(const char *str, struct pt_regs *regs,
299		struct siginfo *info, unsigned long err, unsigned long trap)
300{
301	if (user_mode(regs)) {
302		current->thread.error_code = err;
303		current->thread.trap_no = trap;
304
305		force_sig_info(info->si_signo, info, current);
306	} else {
307		die(str, regs, err);
308	}
309}
310
311static LIST_HEAD(undef_hook);
312static DEFINE_SPINLOCK(undef_lock);
313
314void register_undef_hook(struct undef_hook *hook)
315{
316	unsigned long flags;
317
318	spin_lock_irqsave(&undef_lock, flags);
319	list_add(&hook->node, &undef_hook);
320	spin_unlock_irqrestore(&undef_lock, flags);
321}
322
323void unregister_undef_hook(struct undef_hook *hook)
324{
325	unsigned long flags;
326
327	spin_lock_irqsave(&undef_lock, flags);
328	list_del(&hook->node);
329	spin_unlock_irqrestore(&undef_lock, flags);
330}
331
332static int call_undef_hook(struct pt_regs *regs, unsigned int instr)
333{
334	struct undef_hook *hook;
335	unsigned long flags;
336	int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL;
337
338	spin_lock_irqsave(&undef_lock, flags);
339	list_for_each_entry(hook, &undef_hook, node)
340		if ((instr & hook->instr_mask) == hook->instr_val &&
341		    (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val)
342			fn = hook->fn;
343	spin_unlock_irqrestore(&undef_lock, flags);
344
345	return fn ? fn(regs, instr) : 1;
346}
347
348asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
349{
350	unsigned int correction = thumb_mode(regs) ? 2 : 4;
351	unsigned int instr;
352	siginfo_t info;
353	void __user *pc;
354
355	/*
356	 * According to the ARM ARM, PC is 2 or 4 bytes ahead,
357	 * depending whether we're in Thumb mode or not.
358	 * Correct this offset.
359	 */
360	regs->ARM_pc -= correction;
361
362	pc = (void __user *)instruction_pointer(regs);
363
364	if (processor_mode(regs) == SVC_MODE) {
365		instr = *(u32 *) pc;
366	} else if (thumb_mode(regs)) {
367		get_user(instr, (u16 __user *)pc);
368	} else {
369		get_user(instr, (u32 __user *)pc);
370	}
371
372	if (call_undef_hook(regs, instr) == 0)
373		return;
374
375#ifdef CONFIG_DEBUG_USER
376	if (user_debug & UDBG_UNDEFINED) {
377		printk(KERN_INFO "%s (%d): undefined instruction: pc=%p\n",
378			current->comm, task_pid_nr(current), pc);
379		dump_instr(KERN_INFO, regs);
380	}
381#endif
382
383	info.si_signo = SIGILL;
384	info.si_errno = 0;
385	info.si_code  = ILL_ILLOPC;
386	info.si_addr  = pc;
387
388	arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6);
389}
390
391asmlinkage void do_unexp_fiq (struct pt_regs *regs)
392{
393	printk("Hmm.  Unexpected FIQ received, but trying to continue\n");
394	printk("You may have a hardware problem...\n");
395}
396
397/*
398 * bad_mode handles the impossible case in the vectors.  If you see one of
399 * these, then it's extremely serious, and could mean you have buggy hardware.
400 * It never returns, and never tries to sync.  We hope that we can at least
401 * dump out some state information...
402 */
403asmlinkage void bad_mode(struct pt_regs *regs, int reason)
404{
405	console_verbose();
406
407	printk(KERN_CRIT "Bad mode in %s handler detected\n", handler[reason]);
408
409	die("Oops - bad mode", regs, 0);
410	local_irq_disable();
411	panic("bad mode");
412}
413
414static int bad_syscall(int n, struct pt_regs *regs)
415{
416	struct thread_info *thread = current_thread_info();
417	siginfo_t info;
418
419	if (current->personality != PER_LINUX &&
420	    current->personality != PER_LINUX_32BIT &&
421	    thread->exec_domain->handler) {
422		thread->exec_domain->handler(n, regs);
423		return regs->ARM_r0;
424	}
425
426#ifdef CONFIG_DEBUG_USER
427	if (user_debug & UDBG_SYSCALL) {
428		printk(KERN_ERR "[%d] %s: obsolete system call %08x.\n",
429			task_pid_nr(current), current->comm, n);
430		dump_instr(KERN_ERR, regs);
431	}
432#endif
433
434	info.si_signo = SIGILL;
435	info.si_errno = 0;
436	info.si_code  = ILL_ILLTRP;
437	info.si_addr  = (void __user *)instruction_pointer(regs) -
438			 (thumb_mode(regs) ? 2 : 4);
439
440	arm_notify_die("Oops - bad syscall", regs, &info, n, 0);
441
442	return regs->ARM_r0;
443}
444
445static inline void
446do_cache_op(unsigned long start, unsigned long end, int flags)
447{
448	struct mm_struct *mm = current->active_mm;
449	struct vm_area_struct *vma;
450
451	if (end < start || flags)
452		return;
453
454	down_read(&mm->mmap_sem);
455	vma = find_vma(mm, start);
456	if (vma && vma->vm_start < end) {
457		if (start < vma->vm_start)
458			start = vma->vm_start;
459		if (end > vma->vm_end)
460			end = vma->vm_end;
461
462		flush_cache_user_range(vma, start, end);
463	}
464	up_read(&mm->mmap_sem);
465}
466
467/*
468 * Handle all unrecognised system calls.
469 *  0x9f0000 - 0x9fffff are some more esoteric system calls
470 */
471#define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
472asmlinkage int arm_syscall(int no, struct pt_regs *regs)
473{
474	struct thread_info *thread = current_thread_info();
475	siginfo_t info;
476
477	if ((no >> 16) != (__ARM_NR_BASE>> 16))
478		return bad_syscall(no, regs);
479
480	switch (no & 0xffff) {
481	case 0: /* branch through 0 */
482		info.si_signo = SIGSEGV;
483		info.si_errno = 0;
484		info.si_code  = SEGV_MAPERR;
485		info.si_addr  = NULL;
486
487		arm_notify_die("branch through zero", regs, &info, 0, 0);
488		return 0;
489
490	case NR(breakpoint): /* SWI BREAK_POINT */
491		regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
492		ptrace_break(current, regs);
493		return regs->ARM_r0;
494
495	/*
496	 * Flush a region from virtual address 'r0' to virtual address 'r1'
497	 * _exclusive_.  There is no alignment requirement on either address;
498	 * user space does not need to know the hardware cache layout.
499	 *
500	 * r2 contains flags.  It should ALWAYS be passed as ZERO until it
501	 * is defined to be something else.  For now we ignore it, but may
502	 * the fires of hell burn in your belly if you break this rule. ;)
503	 *
504	 * (at a later date, we may want to allow this call to not flush
505	 * various aspects of the cache.  Passing '0' will guarantee that
506	 * everything necessary gets flushed to maintain consistency in
507	 * the specified region).
508	 */
509	case NR(cacheflush):
510		do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
511		return 0;
512
513	case NR(usr26):
514		if (!(elf_hwcap & HWCAP_26BIT))
515			break;
516		regs->ARM_cpsr &= ~MODE32_BIT;
517		return regs->ARM_r0;
518
519	case NR(usr32):
520		if (!(elf_hwcap & HWCAP_26BIT))
521			break;
522		regs->ARM_cpsr |= MODE32_BIT;
523		return regs->ARM_r0;
524
525	case NR(set_tls):
526		thread->tp_value = regs->ARM_r0;
527		if (tls_emu)
528			return 0;
529		if (has_tls_reg) {
530			asm ("mcr p15, 0, %0, c13, c0, 3"
531				: : "r" (regs->ARM_r0));
532		} else {
533			/*
534			 * User space must never try to access this directly.
535			 * Expect your app to break eventually if you do so.
536			 * The user helper at 0xffff0fe0 must be used instead.
537			 * (see entry-armv.S for details)
538			 */
539			*((unsigned int *)0xffff0ff0) = regs->ARM_r0;
540		}
541		return 0;
542
543#ifdef CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG
544	/*
545	 * Atomically store r1 in *r2 if *r2 is equal to r0 for user space.
546	 * Return zero in r0 if *MEM was changed or non-zero if no exchange
547	 * happened.  Also set the user C flag accordingly.
548	 * If access permissions have to be fixed up then non-zero is
549	 * returned and the operation has to be re-attempted.
550	 *
551	 * *NOTE*: This is a ghost syscall private to the kernel.  Only the
552	 * __kuser_cmpxchg code in entry-armv.S should be aware of its
553	 * existence.  Don't ever use this from user code.
554	 */
555	case NR(cmpxchg):
556	for (;;) {
557		extern void do_DataAbort(unsigned long addr, unsigned int fsr,
558					 struct pt_regs *regs);
559		unsigned long val;
560		unsigned long addr = regs->ARM_r2;
561		struct mm_struct *mm = current->mm;
562		pgd_t *pgd; pmd_t *pmd; pte_t *pte;
563		spinlock_t *ptl;
564
565		regs->ARM_cpsr &= ~PSR_C_BIT;
566		down_read(&mm->mmap_sem);
567		pgd = pgd_offset(mm, addr);
568		if (!pgd_present(*pgd))
569			goto bad_access;
570		pmd = pmd_offset(pgd, addr);
571		if (!pmd_present(*pmd))
572			goto bad_access;
573		pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
574		if (!pte_present(*pte) || !pte_dirty(*pte)) {
575			pte_unmap_unlock(pte, ptl);
576			goto bad_access;
577		}
578		val = *(unsigned long *)addr;
579		val -= regs->ARM_r0;
580		if (val == 0) {
581			*(unsigned long *)addr = regs->ARM_r1;
582			regs->ARM_cpsr |= PSR_C_BIT;
583		}
584		pte_unmap_unlock(pte, ptl);
585		up_read(&mm->mmap_sem);
586		return val;
587
588		bad_access:
589		up_read(&mm->mmap_sem);
590		/* simulate a write access fault */
591		do_DataAbort(addr, 15 + (1 << 11), regs);
592	}
593#endif
594
595	default:
596		/* Calls 9f00xx..9f07ff are defined to return -ENOSYS
597		   if not implemented, rather than raising SIGILL.  This
598		   way the calling program can gracefully determine whether
599		   a feature is supported.  */
600		if ((no & 0xffff) <= 0x7ff)
601			return -ENOSYS;
602		break;
603	}
604#ifdef CONFIG_DEBUG_USER
605	/*
606	 * experience shows that these seem to indicate that
607	 * something catastrophic has happened
608	 */
609	if (user_debug & UDBG_SYSCALL) {
610		printk("[%d] %s: arm syscall %d\n",
611		       task_pid_nr(current), current->comm, no);
612		dump_instr("", regs);
613		if (user_mode(regs)) {
614			__show_regs(regs);
615			c_backtrace(regs->ARM_fp, processor_mode(regs));
616		}
617	}
618#endif
619	info.si_signo = SIGILL;
620	info.si_errno = 0;
621	info.si_code  = ILL_ILLTRP;
622	info.si_addr  = (void __user *)instruction_pointer(regs) -
623			 (thumb_mode(regs) ? 2 : 4);
624
625	arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0);
626	return 0;
627}
628
629#ifdef CONFIG_TLS_REG_EMUL
630
631/*
632 * We might be running on an ARMv6+ processor which should have the TLS
633 * register but for some reason we can't use it, or maybe an SMP system
634 * using a pre-ARMv6 processor (there are apparently a few prototypes like
635 * that in existence) and therefore access to that register must be
636 * emulated.
637 */
638
639static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
640{
641	int reg = (instr >> 12) & 15;
642	if (reg == 15)
643		return 1;
644	regs->uregs[reg] = current_thread_info()->tp_value;
645	regs->ARM_pc += 4;
646	return 0;
647}
648
649static struct undef_hook arm_mrc_hook = {
650	.instr_mask	= 0x0fff0fff,
651	.instr_val	= 0x0e1d0f70,
652	.cpsr_mask	= PSR_T_BIT,
653	.cpsr_val	= 0,
654	.fn		= get_tp_trap,
655};
656
657static int __init arm_mrc_hook_init(void)
658{
659	register_undef_hook(&arm_mrc_hook);
660	return 0;
661}
662
663late_initcall(arm_mrc_hook_init);
664
665#endif
666
667void __bad_xchg(volatile void *ptr, int size)
668{
669	printk("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n",
670		__builtin_return_address(0), ptr, size);
671	BUG();
672}
673EXPORT_SYMBOL(__bad_xchg);
674
675/*
676 * A data abort trap was taken, but we did not handle the instruction.
677 * Try to abort the user program, or panic if it was the kernel.
678 */
679asmlinkage void
680baddataabort(int code, unsigned long instr, struct pt_regs *regs)
681{
682	unsigned long addr = instruction_pointer(regs);
683	siginfo_t info;
684
685#ifdef CONFIG_DEBUG_USER
686	if (user_debug & UDBG_BADABORT) {
687		printk(KERN_ERR "[%d] %s: bad data abort: code %d instr 0x%08lx\n",
688			task_pid_nr(current), current->comm, code, instr);
689		dump_instr(KERN_ERR, regs);
690		show_pte(current->mm, addr);
691	}
692#endif
693
694	info.si_signo = SIGILL;
695	info.si_errno = 0;
696	info.si_code  = ILL_ILLOPC;
697	info.si_addr  = (void __user *)addr;
698
699	arm_notify_die("unknown data abort code", regs, &info, instr, 0);
700}
701
702void __attribute__((noreturn)) __bug(const char *file, int line)
703{
704	printk(KERN_CRIT"kernel BUG at %s:%d!\n", file, line);
705	*(int *)0 = 0;
706
707	/* Avoid "noreturn function does return" */
708	for (;;);
709}
710EXPORT_SYMBOL(__bug);
711
712void __readwrite_bug(const char *fn)
713{
714	printk("%s called, but not implemented\n", fn);
715	BUG();
716}
717EXPORT_SYMBOL(__readwrite_bug);
718
719void __pte_error(const char *file, int line, unsigned long val)
720{
721	printk("%s:%d: bad pte %08lx.\n", file, line, val);
722}
723
724void __pmd_error(const char *file, int line, unsigned long val)
725{
726	printk("%s:%d: bad pmd %08lx.\n", file, line, val);
727}
728
729void __pgd_error(const char *file, int line, unsigned long val)
730{
731	printk("%s:%d: bad pgd %08lx.\n", file, line, val);
732}
733
734asmlinkage void __div0(void)
735{
736	printk("Division by zero in kernel.\n");
737	dump_stack();
738}
739EXPORT_SYMBOL(__div0);
740
741void abort(void)
742{
743	BUG();
744
745	/* if that doesn't kill us, halt */
746	panic("Oops failed to kill thread");
747}
748EXPORT_SYMBOL(abort);
749
750void __init trap_init(void)
751{
752	return;
753}
754
755static void __init kuser_get_tls_init(unsigned long vectors)
756{
757	/*
758	 * vectors + 0xfe0 = __kuser_get_tls
759	 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8
760	 */
761	if (tls_emu || has_tls_reg)
762		memcpy((void *)vectors + 0xfe0, (void *)vectors + 0xfe8, 4);
763}
764
765void __init early_trap_init(void)
766{
767	unsigned long vectors = CONFIG_VECTORS_BASE;
768	extern char __stubs_start[], __stubs_end[];
769	extern char __vectors_start[], __vectors_end[];
770	extern char __kuser_helper_start[], __kuser_helper_end[];
771	int kuser_sz = __kuser_helper_end - __kuser_helper_start;
772
773	/*
774	 * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
775	 * into the vector page, mapped at 0xffff0000, and ensure these
776	 * are visible to the instruction stream.
777	 */
778	memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
779	memcpy((void *)vectors + 0x200, __stubs_start, __stubs_end - __stubs_start);
780	memcpy((void *)vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
781
782	/*
783	 * Do processor specific fixups for the kuser helpers
784	 */
785	kuser_get_tls_init(vectors);
786
787	/*
788	 * Copy signal return handlers into the vector page, and
789	 * set sigreturn to be a pointer to these.
790	 */
791	memcpy((void *)KERN_SIGRETURN_CODE, sigreturn_codes,
792	       sizeof(sigreturn_codes));
793	memcpy((void *)KERN_RESTART_CODE, syscall_restart_code,
794	       sizeof(syscall_restart_code));
795
796	flush_icache_range(vectors, vectors + PAGE_SIZE);
797	modify_domain(DOMAIN_USER, DOMAIN_CLIENT);
798}
799