xref: /linux/arch/arm/kernel/traps.c (revision 834f0c353ae430c1a6ce023c9b77bbd3ff9241a7)
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 <asm/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 
38 static const char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" };
39 
40 void *vectors_page;
41 
42 #ifdef CONFIG_DEBUG_USER
43 unsigned int user_debug;
44 
45 static 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 
53 static void dump_mem(const char *, const char *, unsigned long, unsigned long);
54 
55 void 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  */
73 static 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  */
86 static 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 
125 static 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; 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
164 static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
165 {
166 	unwind_backtrace(regs, tsk);
167 }
168 #else
169 static 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 
205 void dump_stack(void)
206 {
207 	dump_backtrace(NULL, NULL);
208 }
209 
210 EXPORT_SYMBOL(dump_stack);
211 
212 void 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 
229 static 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 	sysfs_printk_last_file();
238 
239 	/* trap and error numbers are mostly meaningless on ARM */
240 	ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV);
241 	if (ret == NOTIFY_STOP)
242 		return ret;
243 
244 	print_modules();
245 	__show_regs(regs);
246 	printk(KERN_EMERG "Process %.*s (pid: %d, stack limit = 0x%p)\n",
247 		TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1);
248 
249 	if (!user_mode(regs) || in_interrupt()) {
250 		dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp,
251 			 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
252 		dump_backtrace(regs, tsk);
253 		dump_instr(KERN_EMERG, regs);
254 	}
255 
256 	return ret;
257 }
258 
259 static DEFINE_SPINLOCK(die_lock);
260 
261 /*
262  * This function is protected against re-entrancy.
263  */
264 void die(const char *str, struct pt_regs *regs, int err)
265 {
266 	struct thread_info *thread = current_thread_info();
267 	int ret;
268 
269 	oops_enter();
270 
271 	spin_lock_irq(&die_lock);
272 	console_verbose();
273 	bust_spinlocks(1);
274 	ret = __die(str, err, thread, regs);
275 
276 	if (regs && kexec_should_crash(thread->task))
277 		crash_kexec(regs);
278 
279 	bust_spinlocks(0);
280 	add_taint(TAINT_DIE);
281 	spin_unlock_irq(&die_lock);
282 	oops_exit();
283 
284 	if (in_interrupt())
285 		panic("Fatal exception in interrupt");
286 	if (panic_on_oops)
287 		panic("Fatal exception");
288 	if (ret != NOTIFY_STOP)
289 		do_exit(SIGSEGV);
290 }
291 
292 void arm_notify_die(const char *str, struct pt_regs *regs,
293 		struct siginfo *info, unsigned long err, unsigned long trap)
294 {
295 	if (user_mode(regs)) {
296 		current->thread.error_code = err;
297 		current->thread.trap_no = trap;
298 
299 		force_sig_info(info->si_signo, info, current);
300 	} else {
301 		die(str, regs, err);
302 	}
303 }
304 
305 static LIST_HEAD(undef_hook);
306 static DEFINE_SPINLOCK(undef_lock);
307 
308 void register_undef_hook(struct undef_hook *hook)
309 {
310 	unsigned long flags;
311 
312 	spin_lock_irqsave(&undef_lock, flags);
313 	list_add(&hook->node, &undef_hook);
314 	spin_unlock_irqrestore(&undef_lock, flags);
315 }
316 
317 void unregister_undef_hook(struct undef_hook *hook)
318 {
319 	unsigned long flags;
320 
321 	spin_lock_irqsave(&undef_lock, flags);
322 	list_del(&hook->node);
323 	spin_unlock_irqrestore(&undef_lock, flags);
324 }
325 
326 static int call_undef_hook(struct pt_regs *regs, unsigned int instr)
327 {
328 	struct undef_hook *hook;
329 	unsigned long flags;
330 	int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL;
331 
332 	spin_lock_irqsave(&undef_lock, flags);
333 	list_for_each_entry(hook, &undef_hook, node)
334 		if ((instr & hook->instr_mask) == hook->instr_val &&
335 		    (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val)
336 			fn = hook->fn;
337 	spin_unlock_irqrestore(&undef_lock, flags);
338 
339 	return fn ? fn(regs, instr) : 1;
340 }
341 
342 asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
343 {
344 	unsigned int correction = thumb_mode(regs) ? 2 : 4;
345 	unsigned int instr;
346 	siginfo_t info;
347 	void __user *pc;
348 
349 	/*
350 	 * According to the ARM ARM, PC is 2 or 4 bytes ahead,
351 	 * depending whether we're in Thumb mode or not.
352 	 * Correct this offset.
353 	 */
354 	regs->ARM_pc -= correction;
355 
356 	pc = (void __user *)instruction_pointer(regs);
357 
358 	if (processor_mode(regs) == SVC_MODE) {
359 		instr = *(u32 *) pc;
360 	} else if (thumb_mode(regs)) {
361 		get_user(instr, (u16 __user *)pc);
362 	} else {
363 		get_user(instr, (u32 __user *)pc);
364 	}
365 
366 	if (call_undef_hook(regs, instr) == 0)
367 		return;
368 
369 #ifdef CONFIG_DEBUG_USER
370 	if (user_debug & UDBG_UNDEFINED) {
371 		printk(KERN_INFO "%s (%d): undefined instruction: pc=%p\n",
372 			current->comm, task_pid_nr(current), pc);
373 		dump_instr(KERN_INFO, regs);
374 	}
375 #endif
376 
377 	info.si_signo = SIGILL;
378 	info.si_errno = 0;
379 	info.si_code  = ILL_ILLOPC;
380 	info.si_addr  = pc;
381 
382 	arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6);
383 }
384 
385 asmlinkage void do_unexp_fiq (struct pt_regs *regs)
386 {
387 	printk("Hmm.  Unexpected FIQ received, but trying to continue\n");
388 	printk("You may have a hardware problem...\n");
389 }
390 
391 /*
392  * bad_mode handles the impossible case in the vectors.  If you see one of
393  * these, then it's extremely serious, and could mean you have buggy hardware.
394  * It never returns, and never tries to sync.  We hope that we can at least
395  * dump out some state information...
396  */
397 asmlinkage void bad_mode(struct pt_regs *regs, int reason)
398 {
399 	console_verbose();
400 
401 	printk(KERN_CRIT "Bad mode in %s handler detected\n", handler[reason]);
402 
403 	die("Oops - bad mode", regs, 0);
404 	local_irq_disable();
405 	panic("bad mode");
406 }
407 
408 static int bad_syscall(int n, struct pt_regs *regs)
409 {
410 	struct thread_info *thread = current_thread_info();
411 	siginfo_t info;
412 
413 	if ((current->personality & PER_MASK) != PER_LINUX &&
414 	    thread->exec_domain->handler) {
415 		thread->exec_domain->handler(n, regs);
416 		return regs->ARM_r0;
417 	}
418 
419 #ifdef CONFIG_DEBUG_USER
420 	if (user_debug & UDBG_SYSCALL) {
421 		printk(KERN_ERR "[%d] %s: obsolete system call %08x.\n",
422 			task_pid_nr(current), current->comm, n);
423 		dump_instr(KERN_ERR, regs);
424 	}
425 #endif
426 
427 	info.si_signo = SIGILL;
428 	info.si_errno = 0;
429 	info.si_code  = ILL_ILLTRP;
430 	info.si_addr  = (void __user *)instruction_pointer(regs) -
431 			 (thumb_mode(regs) ? 2 : 4);
432 
433 	arm_notify_die("Oops - bad syscall", regs, &info, n, 0);
434 
435 	return regs->ARM_r0;
436 }
437 
438 static inline void
439 do_cache_op(unsigned long start, unsigned long end, int flags)
440 {
441 	struct mm_struct *mm = current->active_mm;
442 	struct vm_area_struct *vma;
443 
444 	if (end < start || flags)
445 		return;
446 
447 	down_read(&mm->mmap_sem);
448 	vma = find_vma(mm, start);
449 	if (vma && vma->vm_start < end) {
450 		if (start < vma->vm_start)
451 			start = vma->vm_start;
452 		if (end > vma->vm_end)
453 			end = vma->vm_end;
454 
455 		flush_cache_user_range(vma, start, end);
456 	}
457 	up_read(&mm->mmap_sem);
458 }
459 
460 /*
461  * Handle all unrecognised system calls.
462  *  0x9f0000 - 0x9fffff are some more esoteric system calls
463  */
464 #define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
465 asmlinkage int arm_syscall(int no, struct pt_regs *regs)
466 {
467 	struct thread_info *thread = current_thread_info();
468 	siginfo_t info;
469 
470 	if ((no >> 16) != (__ARM_NR_BASE>> 16))
471 		return bad_syscall(no, regs);
472 
473 	switch (no & 0xffff) {
474 	case 0: /* branch through 0 */
475 		info.si_signo = SIGSEGV;
476 		info.si_errno = 0;
477 		info.si_code  = SEGV_MAPERR;
478 		info.si_addr  = NULL;
479 
480 		arm_notify_die("branch through zero", regs, &info, 0, 0);
481 		return 0;
482 
483 	case NR(breakpoint): /* SWI BREAK_POINT */
484 		regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
485 		ptrace_break(current, regs);
486 		return regs->ARM_r0;
487 
488 	/*
489 	 * Flush a region from virtual address 'r0' to virtual address 'r1'
490 	 * _exclusive_.  There is no alignment requirement on either address;
491 	 * user space does not need to know the hardware cache layout.
492 	 *
493 	 * r2 contains flags.  It should ALWAYS be passed as ZERO until it
494 	 * is defined to be something else.  For now we ignore it, but may
495 	 * the fires of hell burn in your belly if you break this rule. ;)
496 	 *
497 	 * (at a later date, we may want to allow this call to not flush
498 	 * various aspects of the cache.  Passing '0' will guarantee that
499 	 * everything necessary gets flushed to maintain consistency in
500 	 * the specified region).
501 	 */
502 	case NR(cacheflush):
503 		do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
504 		return 0;
505 
506 	case NR(usr26):
507 		if (!(elf_hwcap & HWCAP_26BIT))
508 			break;
509 		regs->ARM_cpsr &= ~MODE32_BIT;
510 		return regs->ARM_r0;
511 
512 	case NR(usr32):
513 		if (!(elf_hwcap & HWCAP_26BIT))
514 			break;
515 		regs->ARM_cpsr |= MODE32_BIT;
516 		return regs->ARM_r0;
517 
518 	case NR(set_tls):
519 		thread->tp_value = regs->ARM_r0;
520 		if (tls_emu)
521 			return 0;
522 		if (has_tls_reg) {
523 			asm ("mcr p15, 0, %0, c13, c0, 3"
524 				: : "r" (regs->ARM_r0));
525 		} else {
526 			/*
527 			 * User space must never try to access this directly.
528 			 * Expect your app to break eventually if you do so.
529 			 * The user helper at 0xffff0fe0 must be used instead.
530 			 * (see entry-armv.S for details)
531 			 */
532 			*((unsigned int *)0xffff0ff0) = regs->ARM_r0;
533 		}
534 		return 0;
535 
536 #ifdef CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG
537 	/*
538 	 * Atomically store r1 in *r2 if *r2 is equal to r0 for user space.
539 	 * Return zero in r0 if *MEM was changed or non-zero if no exchange
540 	 * happened.  Also set the user C flag accordingly.
541 	 * If access permissions have to be fixed up then non-zero is
542 	 * returned and the operation has to be re-attempted.
543 	 *
544 	 * *NOTE*: This is a ghost syscall private to the kernel.  Only the
545 	 * __kuser_cmpxchg code in entry-armv.S should be aware of its
546 	 * existence.  Don't ever use this from user code.
547 	 */
548 	case NR(cmpxchg):
549 	for (;;) {
550 		extern void do_DataAbort(unsigned long addr, unsigned int fsr,
551 					 struct pt_regs *regs);
552 		unsigned long val;
553 		unsigned long addr = regs->ARM_r2;
554 		struct mm_struct *mm = current->mm;
555 		pgd_t *pgd; pmd_t *pmd; pte_t *pte;
556 		spinlock_t *ptl;
557 
558 		regs->ARM_cpsr &= ~PSR_C_BIT;
559 		down_read(&mm->mmap_sem);
560 		pgd = pgd_offset(mm, addr);
561 		if (!pgd_present(*pgd))
562 			goto bad_access;
563 		pmd = pmd_offset(pgd, addr);
564 		if (!pmd_present(*pmd))
565 			goto bad_access;
566 		pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
567 		if (!pte_present(*pte) || !pte_dirty(*pte)) {
568 			pte_unmap_unlock(pte, ptl);
569 			goto bad_access;
570 		}
571 		val = *(unsigned long *)addr;
572 		val -= regs->ARM_r0;
573 		if (val == 0) {
574 			*(unsigned long *)addr = regs->ARM_r1;
575 			regs->ARM_cpsr |= PSR_C_BIT;
576 		}
577 		pte_unmap_unlock(pte, ptl);
578 		up_read(&mm->mmap_sem);
579 		return val;
580 
581 		bad_access:
582 		up_read(&mm->mmap_sem);
583 		/* simulate a write access fault */
584 		do_DataAbort(addr, 15 + (1 << 11), regs);
585 	}
586 #endif
587 
588 	default:
589 		/* Calls 9f00xx..9f07ff are defined to return -ENOSYS
590 		   if not implemented, rather than raising SIGILL.  This
591 		   way the calling program can gracefully determine whether
592 		   a feature is supported.  */
593 		if ((no & 0xffff) <= 0x7ff)
594 			return -ENOSYS;
595 		break;
596 	}
597 #ifdef CONFIG_DEBUG_USER
598 	/*
599 	 * experience shows that these seem to indicate that
600 	 * something catastrophic has happened
601 	 */
602 	if (user_debug & UDBG_SYSCALL) {
603 		printk("[%d] %s: arm syscall %d\n",
604 		       task_pid_nr(current), current->comm, no);
605 		dump_instr("", regs);
606 		if (user_mode(regs)) {
607 			__show_regs(regs);
608 			c_backtrace(regs->ARM_fp, processor_mode(regs));
609 		}
610 	}
611 #endif
612 	info.si_signo = SIGILL;
613 	info.si_errno = 0;
614 	info.si_code  = ILL_ILLTRP;
615 	info.si_addr  = (void __user *)instruction_pointer(regs) -
616 			 (thumb_mode(regs) ? 2 : 4);
617 
618 	arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0);
619 	return 0;
620 }
621 
622 #ifdef CONFIG_TLS_REG_EMUL
623 
624 /*
625  * We might be running on an ARMv6+ processor which should have the TLS
626  * register but for some reason we can't use it, or maybe an SMP system
627  * using a pre-ARMv6 processor (there are apparently a few prototypes like
628  * that in existence) and therefore access to that register must be
629  * emulated.
630  */
631 
632 static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
633 {
634 	int reg = (instr >> 12) & 15;
635 	if (reg == 15)
636 		return 1;
637 	regs->uregs[reg] = current_thread_info()->tp_value;
638 	regs->ARM_pc += 4;
639 	return 0;
640 }
641 
642 static struct undef_hook arm_mrc_hook = {
643 	.instr_mask	= 0x0fff0fff,
644 	.instr_val	= 0x0e1d0f70,
645 	.cpsr_mask	= PSR_T_BIT,
646 	.cpsr_val	= 0,
647 	.fn		= get_tp_trap,
648 };
649 
650 static int __init arm_mrc_hook_init(void)
651 {
652 	register_undef_hook(&arm_mrc_hook);
653 	return 0;
654 }
655 
656 late_initcall(arm_mrc_hook_init);
657 
658 #endif
659 
660 void __bad_xchg(volatile void *ptr, int size)
661 {
662 	printk("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n",
663 		__builtin_return_address(0), ptr, size);
664 	BUG();
665 }
666 EXPORT_SYMBOL(__bad_xchg);
667 
668 /*
669  * A data abort trap was taken, but we did not handle the instruction.
670  * Try to abort the user program, or panic if it was the kernel.
671  */
672 asmlinkage void
673 baddataabort(int code, unsigned long instr, struct pt_regs *regs)
674 {
675 	unsigned long addr = instruction_pointer(regs);
676 	siginfo_t info;
677 
678 #ifdef CONFIG_DEBUG_USER
679 	if (user_debug & UDBG_BADABORT) {
680 		printk(KERN_ERR "[%d] %s: bad data abort: code %d instr 0x%08lx\n",
681 			task_pid_nr(current), current->comm, code, instr);
682 		dump_instr(KERN_ERR, regs);
683 		show_pte(current->mm, addr);
684 	}
685 #endif
686 
687 	info.si_signo = SIGILL;
688 	info.si_errno = 0;
689 	info.si_code  = ILL_ILLOPC;
690 	info.si_addr  = (void __user *)addr;
691 
692 	arm_notify_die("unknown data abort code", regs, &info, instr, 0);
693 }
694 
695 void __attribute__((noreturn)) __bug(const char *file, int line)
696 {
697 	printk(KERN_CRIT"kernel BUG at %s:%d!\n", file, line);
698 	*(int *)0 = 0;
699 
700 	/* Avoid "noreturn function does return" */
701 	for (;;);
702 }
703 EXPORT_SYMBOL(__bug);
704 
705 void __readwrite_bug(const char *fn)
706 {
707 	printk("%s called, but not implemented\n", fn);
708 	BUG();
709 }
710 EXPORT_SYMBOL(__readwrite_bug);
711 
712 void __pte_error(const char *file, int line, pte_t pte)
713 {
714 	printk("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte));
715 }
716 
717 void __pmd_error(const char *file, int line, pmd_t pmd)
718 {
719 	printk("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd));
720 }
721 
722 void __pgd_error(const char *file, int line, pgd_t pgd)
723 {
724 	printk("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd));
725 }
726 
727 asmlinkage void __div0(void)
728 {
729 	printk("Division by zero in kernel.\n");
730 	dump_stack();
731 }
732 EXPORT_SYMBOL(__div0);
733 
734 void abort(void)
735 {
736 	BUG();
737 
738 	/* if that doesn't kill us, halt */
739 	panic("Oops failed to kill thread");
740 }
741 EXPORT_SYMBOL(abort);
742 
743 void __init trap_init(void)
744 {
745 	return;
746 }
747 
748 static void __init kuser_get_tls_init(unsigned long vectors)
749 {
750 	/*
751 	 * vectors + 0xfe0 = __kuser_get_tls
752 	 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8
753 	 */
754 	if (tls_emu || has_tls_reg)
755 		memcpy((void *)vectors + 0xfe0, (void *)vectors + 0xfe8, 4);
756 }
757 
758 void __init early_trap_init(void)
759 {
760 #if defined(CONFIG_CPU_USE_DOMAINS)
761 	unsigned long vectors = CONFIG_VECTORS_BASE;
762 #else
763 	unsigned long vectors = (unsigned long)vectors_page;
764 #endif
765 	extern char __stubs_start[], __stubs_end[];
766 	extern char __vectors_start[], __vectors_end[];
767 	extern char __kuser_helper_start[], __kuser_helper_end[];
768 	int kuser_sz = __kuser_helper_end - __kuser_helper_start;
769 
770 	/*
771 	 * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
772 	 * into the vector page, mapped at 0xffff0000, and ensure these
773 	 * are visible to the instruction stream.
774 	 */
775 	memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
776 	memcpy((void *)vectors + 0x200, __stubs_start, __stubs_end - __stubs_start);
777 	memcpy((void *)vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
778 
779 	/*
780 	 * Do processor specific fixups for the kuser helpers
781 	 */
782 	kuser_get_tls_init(vectors);
783 
784 	/*
785 	 * Copy signal return handlers into the vector page, and
786 	 * set sigreturn to be a pointer to these.
787 	 */
788 	memcpy((void *)(vectors + KERN_SIGRETURN_CODE - CONFIG_VECTORS_BASE),
789 	       sigreturn_codes, sizeof(sigreturn_codes));
790 	memcpy((void *)(vectors + KERN_RESTART_CODE - CONFIG_VECTORS_BASE),
791 	       syscall_restart_code, sizeof(syscall_restart_code));
792 
793 	flush_icache_range(vectors, vectors + PAGE_SIZE);
794 	modify_domain(DOMAIN_USER, DOMAIN_CLIENT);
795 }
796