xref: /openbmc/linux/arch/arm/kernel/traps.c (revision 81d67439)
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 + !!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
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 
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 
258 static DEFINE_SPINLOCK(die_lock);
259 
260 /*
261  * This function is protected against re-entrancy.
262  */
263 void 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 
291 void 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 
304 static LIST_HEAD(undef_hook);
305 static DEFINE_SPINLOCK(undef_lock);
306 
307 void 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 
316 void 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 
325 static 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 
341 asmlinkage 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 		instr = *(u32 *) pc;
359 	} else if (thumb_mode(regs)) {
360 		get_user(instr, (u16 __user *)pc);
361 	} else {
362 		get_user(instr, (u32 __user *)pc);
363 	}
364 
365 	if (call_undef_hook(regs, instr) == 0)
366 		return;
367 
368 #ifdef CONFIG_DEBUG_USER
369 	if (user_debug & UDBG_UNDEFINED) {
370 		printk(KERN_INFO "%s (%d): undefined instruction: pc=%p\n",
371 			current->comm, task_pid_nr(current), pc);
372 		dump_instr(KERN_INFO, regs);
373 	}
374 #endif
375 
376 	info.si_signo = SIGILL;
377 	info.si_errno = 0;
378 	info.si_code  = ILL_ILLOPC;
379 	info.si_addr  = pc;
380 
381 	arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6);
382 }
383 
384 asmlinkage void do_unexp_fiq (struct pt_regs *regs)
385 {
386 	printk("Hmm.  Unexpected FIQ received, but trying to continue\n");
387 	printk("You may have a hardware problem...\n");
388 }
389 
390 /*
391  * bad_mode handles the impossible case in the vectors.  If you see one of
392  * these, then it's extremely serious, and could mean you have buggy hardware.
393  * It never returns, and never tries to sync.  We hope that we can at least
394  * dump out some state information...
395  */
396 asmlinkage void bad_mode(struct pt_regs *regs, int reason)
397 {
398 	console_verbose();
399 
400 	printk(KERN_CRIT "Bad mode in %s handler detected\n", handler[reason]);
401 
402 	die("Oops - bad mode", regs, 0);
403 	local_irq_disable();
404 	panic("bad mode");
405 }
406 
407 static int bad_syscall(int n, struct pt_regs *regs)
408 {
409 	struct thread_info *thread = current_thread_info();
410 	siginfo_t info;
411 
412 	if ((current->personality & PER_MASK) != PER_LINUX &&
413 	    thread->exec_domain->handler) {
414 		thread->exec_domain->handler(n, regs);
415 		return regs->ARM_r0;
416 	}
417 
418 #ifdef CONFIG_DEBUG_USER
419 	if (user_debug & UDBG_SYSCALL) {
420 		printk(KERN_ERR "[%d] %s: obsolete system call %08x.\n",
421 			task_pid_nr(current), current->comm, n);
422 		dump_instr(KERN_ERR, regs);
423 	}
424 #endif
425 
426 	info.si_signo = SIGILL;
427 	info.si_errno = 0;
428 	info.si_code  = ILL_ILLTRP;
429 	info.si_addr  = (void __user *)instruction_pointer(regs) -
430 			 (thumb_mode(regs) ? 2 : 4);
431 
432 	arm_notify_die("Oops - bad syscall", regs, &info, n, 0);
433 
434 	return regs->ARM_r0;
435 }
436 
437 static inline void
438 do_cache_op(unsigned long start, unsigned long end, int flags)
439 {
440 	struct mm_struct *mm = current->active_mm;
441 	struct vm_area_struct *vma;
442 
443 	if (end < start || flags)
444 		return;
445 
446 	down_read(&mm->mmap_sem);
447 	vma = find_vma(mm, start);
448 	if (vma && vma->vm_start < end) {
449 		if (start < vma->vm_start)
450 			start = vma->vm_start;
451 		if (end > vma->vm_end)
452 			end = vma->vm_end;
453 
454 		flush_cache_user_range(vma, start, end);
455 	}
456 	up_read(&mm->mmap_sem);
457 }
458 
459 /*
460  * Handle all unrecognised system calls.
461  *  0x9f0000 - 0x9fffff are some more esoteric system calls
462  */
463 #define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
464 asmlinkage int arm_syscall(int no, struct pt_regs *regs)
465 {
466 	struct thread_info *thread = current_thread_info();
467 	siginfo_t info;
468 
469 	if ((no >> 16) != (__ARM_NR_BASE>> 16))
470 		return bad_syscall(no, regs);
471 
472 	switch (no & 0xffff) {
473 	case 0: /* branch through 0 */
474 		info.si_signo = SIGSEGV;
475 		info.si_errno = 0;
476 		info.si_code  = SEGV_MAPERR;
477 		info.si_addr  = NULL;
478 
479 		arm_notify_die("branch through zero", regs, &info, 0, 0);
480 		return 0;
481 
482 	case NR(breakpoint): /* SWI BREAK_POINT */
483 		regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
484 		ptrace_break(current, regs);
485 		return regs->ARM_r0;
486 
487 	/*
488 	 * Flush a region from virtual address 'r0' to virtual address 'r1'
489 	 * _exclusive_.  There is no alignment requirement on either address;
490 	 * user space does not need to know the hardware cache layout.
491 	 *
492 	 * r2 contains flags.  It should ALWAYS be passed as ZERO until it
493 	 * is defined to be something else.  For now we ignore it, but may
494 	 * the fires of hell burn in your belly if you break this rule. ;)
495 	 *
496 	 * (at a later date, we may want to allow this call to not flush
497 	 * various aspects of the cache.  Passing '0' will guarantee that
498 	 * everything necessary gets flushed to maintain consistency in
499 	 * the specified region).
500 	 */
501 	case NR(cacheflush):
502 		do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
503 		return 0;
504 
505 	case NR(usr26):
506 		if (!(elf_hwcap & HWCAP_26BIT))
507 			break;
508 		regs->ARM_cpsr &= ~MODE32_BIT;
509 		return regs->ARM_r0;
510 
511 	case NR(usr32):
512 		if (!(elf_hwcap & HWCAP_26BIT))
513 			break;
514 		regs->ARM_cpsr |= MODE32_BIT;
515 		return regs->ARM_r0;
516 
517 	case NR(set_tls):
518 		thread->tp_value = regs->ARM_r0;
519 		if (tls_emu)
520 			return 0;
521 		if (has_tls_reg) {
522 			asm ("mcr p15, 0, %0, c13, c0, 3"
523 				: : "r" (regs->ARM_r0));
524 		} else {
525 			/*
526 			 * User space must never try to access this directly.
527 			 * Expect your app to break eventually if you do so.
528 			 * The user helper at 0xffff0fe0 must be used instead.
529 			 * (see entry-armv.S for details)
530 			 */
531 			*((unsigned int *)0xffff0ff0) = regs->ARM_r0;
532 		}
533 		return 0;
534 
535 #ifdef CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG
536 	/*
537 	 * Atomically store r1 in *r2 if *r2 is equal to r0 for user space.
538 	 * Return zero in r0 if *MEM was changed or non-zero if no exchange
539 	 * happened.  Also set the user C flag accordingly.
540 	 * If access permissions have to be fixed up then non-zero is
541 	 * returned and the operation has to be re-attempted.
542 	 *
543 	 * *NOTE*: This is a ghost syscall private to the kernel.  Only the
544 	 * __kuser_cmpxchg code in entry-armv.S should be aware of its
545 	 * existence.  Don't ever use this from user code.
546 	 */
547 	case NR(cmpxchg):
548 	for (;;) {
549 		extern void do_DataAbort(unsigned long addr, unsigned int fsr,
550 					 struct pt_regs *regs);
551 		unsigned long val;
552 		unsigned long addr = regs->ARM_r2;
553 		struct mm_struct *mm = current->mm;
554 		pgd_t *pgd; pmd_t *pmd; pte_t *pte;
555 		spinlock_t *ptl;
556 
557 		regs->ARM_cpsr &= ~PSR_C_BIT;
558 		down_read(&mm->mmap_sem);
559 		pgd = pgd_offset(mm, addr);
560 		if (!pgd_present(*pgd))
561 			goto bad_access;
562 		pmd = pmd_offset(pgd, addr);
563 		if (!pmd_present(*pmd))
564 			goto bad_access;
565 		pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
566 		if (!pte_present(*pte) || !pte_write(*pte) || !pte_dirty(*pte)) {
567 			pte_unmap_unlock(pte, ptl);
568 			goto bad_access;
569 		}
570 		val = *(unsigned long *)addr;
571 		val -= regs->ARM_r0;
572 		if (val == 0) {
573 			*(unsigned long *)addr = regs->ARM_r1;
574 			regs->ARM_cpsr |= PSR_C_BIT;
575 		}
576 		pte_unmap_unlock(pte, ptl);
577 		up_read(&mm->mmap_sem);
578 		return val;
579 
580 		bad_access:
581 		up_read(&mm->mmap_sem);
582 		/* simulate a write access fault */
583 		do_DataAbort(addr, 15 + (1 << 11), regs);
584 	}
585 #endif
586 
587 	default:
588 		/* Calls 9f00xx..9f07ff are defined to return -ENOSYS
589 		   if not implemented, rather than raising SIGILL.  This
590 		   way the calling program can gracefully determine whether
591 		   a feature is supported.  */
592 		if ((no & 0xffff) <= 0x7ff)
593 			return -ENOSYS;
594 		break;
595 	}
596 #ifdef CONFIG_DEBUG_USER
597 	/*
598 	 * experience shows that these seem to indicate that
599 	 * something catastrophic has happened
600 	 */
601 	if (user_debug & UDBG_SYSCALL) {
602 		printk("[%d] %s: arm syscall %d\n",
603 		       task_pid_nr(current), current->comm, no);
604 		dump_instr("", regs);
605 		if (user_mode(regs)) {
606 			__show_regs(regs);
607 			c_backtrace(regs->ARM_fp, processor_mode(regs));
608 		}
609 	}
610 #endif
611 	info.si_signo = SIGILL;
612 	info.si_errno = 0;
613 	info.si_code  = ILL_ILLTRP;
614 	info.si_addr  = (void __user *)instruction_pointer(regs) -
615 			 (thumb_mode(regs) ? 2 : 4);
616 
617 	arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0);
618 	return 0;
619 }
620 
621 #ifdef CONFIG_TLS_REG_EMUL
622 
623 /*
624  * We might be running on an ARMv6+ processor which should have the TLS
625  * register but for some reason we can't use it, or maybe an SMP system
626  * using a pre-ARMv6 processor (there are apparently a few prototypes like
627  * that in existence) and therefore access to that register must be
628  * emulated.
629  */
630 
631 static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
632 {
633 	int reg = (instr >> 12) & 15;
634 	if (reg == 15)
635 		return 1;
636 	regs->uregs[reg] = current_thread_info()->tp_value;
637 	regs->ARM_pc += 4;
638 	return 0;
639 }
640 
641 static struct undef_hook arm_mrc_hook = {
642 	.instr_mask	= 0x0fff0fff,
643 	.instr_val	= 0x0e1d0f70,
644 	.cpsr_mask	= PSR_T_BIT,
645 	.cpsr_val	= 0,
646 	.fn		= get_tp_trap,
647 };
648 
649 static int __init arm_mrc_hook_init(void)
650 {
651 	register_undef_hook(&arm_mrc_hook);
652 	return 0;
653 }
654 
655 late_initcall(arm_mrc_hook_init);
656 
657 #endif
658 
659 void __bad_xchg(volatile void *ptr, int size)
660 {
661 	printk("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n",
662 		__builtin_return_address(0), ptr, size);
663 	BUG();
664 }
665 EXPORT_SYMBOL(__bad_xchg);
666 
667 /*
668  * A data abort trap was taken, but we did not handle the instruction.
669  * Try to abort the user program, or panic if it was the kernel.
670  */
671 asmlinkage void
672 baddataabort(int code, unsigned long instr, struct pt_regs *regs)
673 {
674 	unsigned long addr = instruction_pointer(regs);
675 	siginfo_t info;
676 
677 #ifdef CONFIG_DEBUG_USER
678 	if (user_debug & UDBG_BADABORT) {
679 		printk(KERN_ERR "[%d] %s: bad data abort: code %d instr 0x%08lx\n",
680 			task_pid_nr(current), current->comm, code, instr);
681 		dump_instr(KERN_ERR, regs);
682 		show_pte(current->mm, addr);
683 	}
684 #endif
685 
686 	info.si_signo = SIGILL;
687 	info.si_errno = 0;
688 	info.si_code  = ILL_ILLOPC;
689 	info.si_addr  = (void __user *)addr;
690 
691 	arm_notify_die("unknown data abort code", regs, &info, instr, 0);
692 }
693 
694 void __attribute__((noreturn)) __bug(const char *file, int line)
695 {
696 	printk(KERN_CRIT"kernel BUG at %s:%d!\n", file, line);
697 	*(int *)0 = 0;
698 
699 	/* Avoid "noreturn function does return" */
700 	for (;;);
701 }
702 EXPORT_SYMBOL(__bug);
703 
704 void __readwrite_bug(const char *fn)
705 {
706 	printk("%s called, but not implemented\n", fn);
707 	BUG();
708 }
709 EXPORT_SYMBOL(__readwrite_bug);
710 
711 void __pte_error(const char *file, int line, pte_t pte)
712 {
713 	printk("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte));
714 }
715 
716 void __pmd_error(const char *file, int line, pmd_t pmd)
717 {
718 	printk("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd));
719 }
720 
721 void __pgd_error(const char *file, int line, pgd_t pgd)
722 {
723 	printk("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd));
724 }
725 
726 asmlinkage void __div0(void)
727 {
728 	printk("Division by zero in kernel.\n");
729 	dump_stack();
730 }
731 EXPORT_SYMBOL(__div0);
732 
733 void abort(void)
734 {
735 	BUG();
736 
737 	/* if that doesn't kill us, halt */
738 	panic("Oops failed to kill thread");
739 }
740 EXPORT_SYMBOL(abort);
741 
742 void __init trap_init(void)
743 {
744 	return;
745 }
746 
747 static void __init kuser_get_tls_init(unsigned long vectors)
748 {
749 	/*
750 	 * vectors + 0xfe0 = __kuser_get_tls
751 	 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8
752 	 */
753 	if (tls_emu || has_tls_reg)
754 		memcpy((void *)vectors + 0xfe0, (void *)vectors + 0xfe8, 4);
755 }
756 
757 void __init early_trap_init(void)
758 {
759 #if defined(CONFIG_CPU_USE_DOMAINS)
760 	unsigned long vectors = CONFIG_VECTORS_BASE;
761 #else
762 	unsigned long vectors = (unsigned long)vectors_page;
763 #endif
764 	extern char __stubs_start[], __stubs_end[];
765 	extern char __vectors_start[], __vectors_end[];
766 	extern char __kuser_helper_start[], __kuser_helper_end[];
767 	int kuser_sz = __kuser_helper_end - __kuser_helper_start;
768 
769 	/*
770 	 * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
771 	 * into the vector page, mapped at 0xffff0000, and ensure these
772 	 * are visible to the instruction stream.
773 	 */
774 	memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
775 	memcpy((void *)vectors + 0x200, __stubs_start, __stubs_end - __stubs_start);
776 	memcpy((void *)vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
777 
778 	/*
779 	 * Do processor specific fixups for the kuser helpers
780 	 */
781 	kuser_get_tls_init(vectors);
782 
783 	/*
784 	 * Copy signal return handlers into the vector page, and
785 	 * set sigreturn to be a pointer to these.
786 	 */
787 	memcpy((void *)(vectors + KERN_SIGRETURN_CODE - CONFIG_VECTORS_BASE),
788 	       sigreturn_codes, sizeof(sigreturn_codes));
789 	memcpy((void *)(vectors + KERN_RESTART_CODE - CONFIG_VECTORS_BASE),
790 	       syscall_restart_code, sizeof(syscall_restart_code));
791 
792 	flush_icache_range(vectors, vectors + PAGE_SIZE);
793 	modify_domain(DOMAIN_USER, DOMAIN_CLIENT);
794 }
795