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/kprobes.h>
 23#include <linux/module.h>
 24#include <linux/kexec.h>
 25#include <linux/bug.h>
 26#include <linux/delay.h>
 27#include <linux/init.h>
 28#include <linux/sched/signal.h>
 29#include <linux/sched/debug.h>
 30#include <linux/sched/task_stack.h>
 31#include <linux/irq.h>
 32
 33#include <linux/atomic.h>
 34#include <asm/cacheflush.h>
 35#include <asm/exception.h>
 36#include <asm/unistd.h>
 37#include <asm/traps.h>
 38#include <asm/ptrace.h>
 39#include <asm/unwind.h>
 40#include <asm/tls.h>
 41#include <asm/system_misc.h>
 42#include <asm/opcodes.h>
 43
 44
 45static const char *handler[]= {
 46	"prefetch abort",
 47	"data abort",
 48	"address exception",
 49	"interrupt",
 50	"undefined instruction",
 51};
 52
 53void *vectors_page;
 54
 55#ifdef CONFIG_DEBUG_USER
 56unsigned int user_debug;
 57
 58static int __init user_debug_setup(char *str)
 59{
 60	get_option(&str, &user_debug);
 61	return 1;
 62}
 63__setup("user_debug=", user_debug_setup);
 64#endif
 65
 66static void dump_mem(const char *, const char *, unsigned long, unsigned long);
 67
 68void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame)
 69{
 70#ifdef CONFIG_KALLSYMS
 71	printk("[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from);
 72#else
 73	printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
 74#endif
 75
 76	if (in_entry_text(from))
 77		dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs));
 78}
 79
 80void dump_backtrace_stm(u32 *stack, u32 instruction)
 81{
 82	char str[80], *p;
 83	unsigned int x;
 84	int reg;
 85
 86	for (reg = 10, x = 0, p = str; reg >= 0; reg--) {
 87		if (instruction & BIT(reg)) {
 88			p += sprintf(p, " r%d:%08x", reg, *stack--);
 89			if (++x == 6) {
 90				x = 0;
 91				p = str;
 92				printk("%s\n", str);
 93			}
 94		}
 95	}
 96	if (p != str)
 97		printk("%s\n", str);
 98}
 99
100#ifndef CONFIG_ARM_UNWIND
101/*
102 * Stack pointers should always be within the kernels view of
103 * physical memory.  If it is not there, then we can't dump
104 * out any information relating to the stack.
105 */
106static int verify_stack(unsigned long sp)
107{
108	if (sp < PAGE_OFFSET ||
109	    (sp > (unsigned long)high_memory && high_memory != NULL))
110		return -EFAULT;
111
112	return 0;
113}
114#endif
115
116/*
117 * Dump out the contents of some memory nicely...
118 */
119static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
120		     unsigned long top)
121{
122	unsigned long first;
123	mm_segment_t fs;
124	int i;
125
126	/*
127	 * We need to switch to kernel mode so that we can use __get_user
128	 * to safely read from kernel space.  Note that we now dump the
129	 * code first, just in case the backtrace kills us.
130	 */
131	fs = get_fs();
132	set_fs(KERNEL_DS);
133
134	printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top);
135
136	for (first = bottom & ~31; first < top; first += 32) {
137		unsigned long p;
138		char str[sizeof(" 12345678") * 8 + 1];
139
140		memset(str, ' ', sizeof(str));
141		str[sizeof(str) - 1] = '\0';
142
143		for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
144			if (p >= bottom && p < top) {
145				unsigned long val;
146				if (__get_user(val, (unsigned long *)p) == 0)
147					sprintf(str + i * 9, " %08lx", val);
148				else
149					sprintf(str + i * 9, " ????????");
150			}
151		}
152		printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
153	}
154
155	set_fs(fs);
156}
157
158static void __dump_instr(const char *lvl, struct pt_regs *regs)
159{
160	unsigned long addr = instruction_pointer(regs);
161	const int thumb = thumb_mode(regs);
162	const int width = thumb ? 4 : 8;
163	char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
164	int i;
165
166	/*
167	 * Note that we now dump the code first, just in case the backtrace
168	 * kills us.
169	 */
170
171	for (i = -4; i < 1 + !!thumb; i++) {
172		unsigned int val, bad;
173
174		if (thumb)
175			bad = get_user(val, &((u16 *)addr)[i]);
176		else
177			bad = get_user(val, &((u32 *)addr)[i]);
178
179		if (!bad)
180			p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ",
181					width, val);
182		else {
183			p += sprintf(p, "bad PC value");
184			break;
185		}
186	}
187	printk("%sCode: %s\n", lvl, str);
188}
189
190static void dump_instr(const char *lvl, struct pt_regs *regs)
191{
192	mm_segment_t fs;
193
194	if (!user_mode(regs)) {
195		fs = get_fs();
196		set_fs(KERNEL_DS);
197		__dump_instr(lvl, regs);
198		set_fs(fs);
199	} else {
200		__dump_instr(lvl, regs);
201	}
202}
203
204#ifdef CONFIG_ARM_UNWIND
205static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
206{
207	unwind_backtrace(regs, tsk);
208}
209#else
210static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
211{
212	unsigned int fp, mode;
213	int ok = 1;
214
215	printk("Backtrace: ");
216
217	if (!tsk)
218		tsk = current;
219
220	if (regs) {
221		fp = frame_pointer(regs);
222		mode = processor_mode(regs);
223	} else if (tsk != current) {
224		fp = thread_saved_fp(tsk);
225		mode = 0x10;
226	} else {
227		asm("mov %0, fp" : "=r" (fp) : : "cc");
228		mode = 0x10;
229	}
230
231	if (!fp) {
232		pr_cont("no frame pointer");
233		ok = 0;
234	} else if (verify_stack(fp)) {
235		pr_cont("invalid frame pointer 0x%08x", fp);
236		ok = 0;
237	} else if (fp < (unsigned long)end_of_stack(tsk))
238		pr_cont("frame pointer underflow");
239	pr_cont("\n");
240
241	if (ok)
242		c_backtrace(fp, mode);
243}
244#endif
245
246void show_stack(struct task_struct *tsk, unsigned long *sp)
247{
248	dump_backtrace(NULL, tsk);
249	barrier();
250}
251
252#ifdef CONFIG_PREEMPT
253#define S_PREEMPT " PREEMPT"
254#else
255#define S_PREEMPT ""
256#endif
257#ifdef CONFIG_SMP
258#define S_SMP " SMP"
259#else
260#define S_SMP ""
261#endif
262#ifdef CONFIG_THUMB2_KERNEL
263#define S_ISA " THUMB2"
264#else
265#define S_ISA " ARM"
266#endif
267
268static int __die(const char *str, int err, struct pt_regs *regs)
269{
270	struct task_struct *tsk = current;
271	static int die_counter;
272	int ret;
273
274	pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP S_ISA "\n",
275	         str, err, ++die_counter);
276
277	/* trap and error numbers are mostly meaningless on ARM */
278	ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV);
279	if (ret == NOTIFY_STOP)
280		return 1;
281
282	print_modules();
283	__show_regs(regs);
284	pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
285		 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk));
286
287	if (!user_mode(regs) || in_interrupt()) {
288		dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp,
289			 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
290		dump_backtrace(regs, tsk);
291		dump_instr(KERN_EMERG, regs);
292	}
293
294	return 0;
295}
296
297static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
298static int die_owner = -1;
299static unsigned int die_nest_count;
300
301static unsigned long oops_begin(void)
302{
303	int cpu;
304	unsigned long flags;
305
306	oops_enter();
307
308	/* racy, but better than risking deadlock. */
309	raw_local_irq_save(flags);
310	cpu = smp_processor_id();
311	if (!arch_spin_trylock(&die_lock)) {
312		if (cpu == die_owner)
313			/* nested oops. should stop eventually */;
314		else
315			arch_spin_lock(&die_lock);
316	}
317	die_nest_count++;
318	die_owner = cpu;
319	console_verbose();
320	bust_spinlocks(1);
321	return flags;
322}
323
324static void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
325{
326	if (regs && kexec_should_crash(current))
327		crash_kexec(regs);
328
329	bust_spinlocks(0);
330	die_owner = -1;
331	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
332	die_nest_count--;
333	if (!die_nest_count)
334		/* Nest count reaches zero, release the lock. */
335		arch_spin_unlock(&die_lock);
336	raw_local_irq_restore(flags);
337	oops_exit();
338
339	if (in_interrupt())
340		panic("Fatal exception in interrupt");
341	if (panic_on_oops)
342		panic("Fatal exception");
343	if (signr)
344		do_exit(signr);
345}
346
347/*
348 * This function is protected against re-entrancy.
349 */
350void die(const char *str, struct pt_regs *regs, int err)
351{
352	enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE;
353	unsigned long flags = oops_begin();
354	int sig = SIGSEGV;
355
356	if (!user_mode(regs))
357		bug_type = report_bug(regs->ARM_pc, regs);
358	if (bug_type != BUG_TRAP_TYPE_NONE)
359		str = "Oops - BUG";
360
361	if (__die(str, err, regs))
362		sig = 0;
363
364	oops_end(flags, regs, sig);
365}
366
367void arm_notify_die(const char *str, struct pt_regs *regs,
368		struct siginfo *info, unsigned long err, unsigned long trap)
 
369{
370	if (user_mode(regs)) {
371		current->thread.error_code = err;
372		current->thread.trap_no = trap;
373
374		force_sig_info(info->si_signo, info, current);
375	} else {
376		die(str, regs, err);
377	}
378}
379
380#ifdef CONFIG_GENERIC_BUG
381
382int is_valid_bugaddr(unsigned long pc)
383{
384#ifdef CONFIG_THUMB2_KERNEL
385	u16 bkpt;
386	u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE);
387#else
388	u32 bkpt;
389	u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE);
390#endif
391
392	if (probe_kernel_address((unsigned *)pc, bkpt))
393		return 0;
394
395	return bkpt == insn;
396}
397
398#endif
399
400static LIST_HEAD(undef_hook);
401static DEFINE_RAW_SPINLOCK(undef_lock);
402
403void register_undef_hook(struct undef_hook *hook)
404{
405	unsigned long flags;
406
407	raw_spin_lock_irqsave(&undef_lock, flags);
408	list_add(&hook->node, &undef_hook);
409	raw_spin_unlock_irqrestore(&undef_lock, flags);
410}
411
412void unregister_undef_hook(struct undef_hook *hook)
413{
414	unsigned long flags;
415
416	raw_spin_lock_irqsave(&undef_lock, flags);
417	list_del(&hook->node);
418	raw_spin_unlock_irqrestore(&undef_lock, flags);
419}
420
421static nokprobe_inline
422int call_undef_hook(struct pt_regs *regs, unsigned int instr)
423{
424	struct undef_hook *hook;
425	unsigned long flags;
426	int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL;
427
428	raw_spin_lock_irqsave(&undef_lock, flags);
429	list_for_each_entry(hook, &undef_hook, node)
430		if ((instr & hook->instr_mask) == hook->instr_val &&
431		    (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val)
432			fn = hook->fn;
433	raw_spin_unlock_irqrestore(&undef_lock, flags);
434
435	return fn ? fn(regs, instr) : 1;
436}
437
438asmlinkage void do_undefinstr(struct pt_regs *regs)
439{
440	unsigned int instr;
441	siginfo_t info;
442	void __user *pc;
443
444	pc = (void __user *)instruction_pointer(regs);
445
446	if (processor_mode(regs) == SVC_MODE) {
447#ifdef CONFIG_THUMB2_KERNEL
448		if (thumb_mode(regs)) {
449			instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]);
450			if (is_wide_instruction(instr)) {
451				u16 inst2;
452				inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]);
453				instr = __opcode_thumb32_compose(instr, inst2);
454			}
455		} else
456#endif
457			instr = __mem_to_opcode_arm(*(u32 *) pc);
458	} else if (thumb_mode(regs)) {
459		if (get_user(instr, (u16 __user *)pc))
460			goto die_sig;
461		instr = __mem_to_opcode_thumb16(instr);
462		if (is_wide_instruction(instr)) {
463			unsigned int instr2;
464			if (get_user(instr2, (u16 __user *)pc+1))
465				goto die_sig;
466			instr2 = __mem_to_opcode_thumb16(instr2);
467			instr = __opcode_thumb32_compose(instr, instr2);
468		}
469	} else {
470		if (get_user(instr, (u32 __user *)pc))
471			goto die_sig;
472		instr = __mem_to_opcode_arm(instr);
473	}
474
475	if (call_undef_hook(regs, instr) == 0)
476		return;
477
478die_sig:
479#ifdef CONFIG_DEBUG_USER
480	if (user_debug & UDBG_UNDEFINED) {
481		pr_info("%s (%d): undefined instruction: pc=%p\n",
482			current->comm, task_pid_nr(current), pc);
483		__show_regs(regs);
484		dump_instr(KERN_INFO, regs);
485	}
486#endif
487
488	info.si_signo = SIGILL;
489	info.si_errno = 0;
490	info.si_code  = ILL_ILLOPC;
491	info.si_addr  = pc;
492
493	arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6);
494}
495NOKPROBE_SYMBOL(do_undefinstr)
496
497/*
498 * Handle FIQ similarly to NMI on x86 systems.
499 *
500 * The runtime environment for NMIs is extremely restrictive
501 * (NMIs can pre-empt critical sections meaning almost all locking is
502 * forbidden) meaning this default FIQ handling must only be used in
503 * circumstances where non-maskability improves robustness, such as
504 * watchdog or debug logic.
505 *
506 * This handler is not appropriate for general purpose use in drivers
507 * platform code and can be overrideen using set_fiq_handler.
508 */
509asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs)
510{
511	struct pt_regs *old_regs = set_irq_regs(regs);
512
513	nmi_enter();
514
515	/* nop. FIQ handlers for special arch/arm features can be added here. */
516
517	nmi_exit();
518
519	set_irq_regs(old_regs);
520}
521
522/*
523 * bad_mode handles the impossible case in the vectors.  If you see one of
524 * these, then it's extremely serious, and could mean you have buggy hardware.
525 * It never returns, and never tries to sync.  We hope that we can at least
526 * dump out some state information...
527 */
528asmlinkage void bad_mode(struct pt_regs *regs, int reason)
529{
530	console_verbose();
531
532	pr_crit("Bad mode in %s handler detected\n", handler[reason]);
533
534	die("Oops - bad mode", regs, 0);
535	local_irq_disable();
536	panic("bad mode");
537}
538
539static int bad_syscall(int n, struct pt_regs *regs)
540{
541	siginfo_t info;
542
543	if ((current->personality & PER_MASK) != PER_LINUX) {
544		send_sig(SIGSEGV, current, 1);
545		return regs->ARM_r0;
546	}
547
548#ifdef CONFIG_DEBUG_USER
549	if (user_debug & UDBG_SYSCALL) {
550		pr_err("[%d] %s: obsolete system call %08x.\n",
551			task_pid_nr(current), current->comm, n);
552		dump_instr(KERN_ERR, regs);
553	}
554#endif
555
556	info.si_signo = SIGILL;
557	info.si_errno = 0;
558	info.si_code  = ILL_ILLTRP;
559	info.si_addr  = (void __user *)instruction_pointer(regs) -
560			 (thumb_mode(regs) ? 2 : 4);
561
562	arm_notify_die("Oops - bad syscall", regs, &info, n, 0);
563
564	return regs->ARM_r0;
565}
566
567static inline int
568__do_cache_op(unsigned long start, unsigned long end)
569{
570	int ret;
571
572	do {
573		unsigned long chunk = min(PAGE_SIZE, end - start);
574
575		if (fatal_signal_pending(current))
576			return 0;
577
578		ret = flush_cache_user_range(start, start + chunk);
579		if (ret)
580			return ret;
581
582		cond_resched();
583		start += chunk;
584	} while (start < end);
585
586	return 0;
587}
588
589static inline int
590do_cache_op(unsigned long start, unsigned long end, int flags)
591{
592	if (end < start || flags)
593		return -EINVAL;
594
595	if (!access_ok(VERIFY_READ, start, end - start))
596		return -EFAULT;
597
598	return __do_cache_op(start, end);
599}
600
601/*
602 * Handle all unrecognised system calls.
603 *  0x9f0000 - 0x9fffff are some more esoteric system calls
604 */
605#define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
606asmlinkage int arm_syscall(int no, struct pt_regs *regs)
607{
608	siginfo_t info;
609
610	if ((no >> 16) != (__ARM_NR_BASE>> 16))
611		return bad_syscall(no, regs);
612
613	switch (no & 0xffff) {
614	case 0: /* branch through 0 */
615		info.si_signo = SIGSEGV;
616		info.si_errno = 0;
617		info.si_code  = SEGV_MAPERR;
618		info.si_addr  = NULL;
619
620		arm_notify_die("branch through zero", regs, &info, 0, 0);
621		return 0;
622
623	case NR(breakpoint): /* SWI BREAK_POINT */
624		regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
625		ptrace_break(current, regs);
626		return regs->ARM_r0;
627
628	/*
629	 * Flush a region from virtual address 'r0' to virtual address 'r1'
630	 * _exclusive_.  There is no alignment requirement on either address;
631	 * user space does not need to know the hardware cache layout.
632	 *
633	 * r2 contains flags.  It should ALWAYS be passed as ZERO until it
634	 * is defined to be something else.  For now we ignore it, but may
635	 * the fires of hell burn in your belly if you break this rule. ;)
636	 *
637	 * (at a later date, we may want to allow this call to not flush
638	 * various aspects of the cache.  Passing '0' will guarantee that
639	 * everything necessary gets flushed to maintain consistency in
640	 * the specified region).
641	 */
642	case NR(cacheflush):
643		return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
644
645	case NR(usr26):
646		if (!(elf_hwcap & HWCAP_26BIT))
647			break;
648		regs->ARM_cpsr &= ~MODE32_BIT;
649		return regs->ARM_r0;
650
651	case NR(usr32):
652		if (!(elf_hwcap & HWCAP_26BIT))
653			break;
654		regs->ARM_cpsr |= MODE32_BIT;
655		return regs->ARM_r0;
656
657	case NR(set_tls):
658		set_tls(regs->ARM_r0);
659		return 0;
660
661	case NR(get_tls):
662		return current_thread_info()->tp_value[0];
663
664	default:
665		/* Calls 9f00xx..9f07ff are defined to return -ENOSYS
666		   if not implemented, rather than raising SIGILL.  This
667		   way the calling program can gracefully determine whether
668		   a feature is supported.  */
669		if ((no & 0xffff) <= 0x7ff)
670			return -ENOSYS;
671		break;
672	}
673#ifdef CONFIG_DEBUG_USER
674	/*
675	 * experience shows that these seem to indicate that
676	 * something catastrophic has happened
677	 */
678	if (user_debug & UDBG_SYSCALL) {
679		pr_err("[%d] %s: arm syscall %d\n",
680		       task_pid_nr(current), current->comm, no);
681		dump_instr("", regs);
682		if (user_mode(regs)) {
683			__show_regs(regs);
684			c_backtrace(frame_pointer(regs), processor_mode(regs));
685		}
686	}
687#endif
688	info.si_signo = SIGILL;
689	info.si_errno = 0;
690	info.si_code  = ILL_ILLTRP;
691	info.si_addr  = (void __user *)instruction_pointer(regs) -
692			 (thumb_mode(regs) ? 2 : 4);
693
694	arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0);
695	return 0;
696}
697
698#ifdef CONFIG_TLS_REG_EMUL
699
700/*
701 * We might be running on an ARMv6+ processor which should have the TLS
702 * register but for some reason we can't use it, or maybe an SMP system
703 * using a pre-ARMv6 processor (there are apparently a few prototypes like
704 * that in existence) and therefore access to that register must be
705 * emulated.
706 */
707
708static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
709{
710	int reg = (instr >> 12) & 15;
711	if (reg == 15)
712		return 1;
713	regs->uregs[reg] = current_thread_info()->tp_value[0];
714	regs->ARM_pc += 4;
715	return 0;
716}
717
718static struct undef_hook arm_mrc_hook = {
719	.instr_mask	= 0x0fff0fff,
720	.instr_val	= 0x0e1d0f70,
721	.cpsr_mask	= PSR_T_BIT,
722	.cpsr_val	= 0,
723	.fn		= get_tp_trap,
724};
725
726static int __init arm_mrc_hook_init(void)
727{
728	register_undef_hook(&arm_mrc_hook);
729	return 0;
730}
731
732late_initcall(arm_mrc_hook_init);
733
734#endif
735
736/*
737 * A data abort trap was taken, but we did not handle the instruction.
738 * Try to abort the user program, or panic if it was the kernel.
739 */
740asmlinkage void
741baddataabort(int code, unsigned long instr, struct pt_regs *regs)
742{
743	unsigned long addr = instruction_pointer(regs);
744	siginfo_t info;
745
746#ifdef CONFIG_DEBUG_USER
747	if (user_debug & UDBG_BADABORT) {
 
748		pr_err("[%d] %s: bad data abort: code %d instr 0x%08lx\n",
749		       task_pid_nr(current), current->comm, code, instr);
750		dump_instr(KERN_ERR, regs);
751		show_pte(current->mm, addr);
752	}
753#endif
754
755	info.si_signo = SIGILL;
756	info.si_errno = 0;
757	info.si_code  = ILL_ILLOPC;
758	info.si_addr  = (void __user *)addr;
759
760	arm_notify_die("unknown data abort code", regs, &info, instr, 0);
761}
762
763void __readwrite_bug(const char *fn)
764{
765	pr_err("%s called, but not implemented\n", fn);
766	BUG();
767}
768EXPORT_SYMBOL(__readwrite_bug);
769
770void __pte_error(const char *file, int line, pte_t pte)
771{
772	pr_err("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte));
773}
774
775void __pmd_error(const char *file, int line, pmd_t pmd)
776{
777	pr_err("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd));
778}
779
780void __pgd_error(const char *file, int line, pgd_t pgd)
781{
782	pr_err("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd));
783}
784
785asmlinkage void __div0(void)
786{
787	pr_err("Division by zero in kernel.\n");
788	dump_stack();
789}
790EXPORT_SYMBOL(__div0);
791
792void abort(void)
793{
794	BUG();
795
796	/* if that doesn't kill us, halt */
797	panic("Oops failed to kill thread");
798}
799
800void __init trap_init(void)
801{
802	return;
803}
804
805#ifdef CONFIG_KUSER_HELPERS
806static void __init kuser_init(void *vectors)
807{
808	extern char __kuser_helper_start[], __kuser_helper_end[];
809	int kuser_sz = __kuser_helper_end - __kuser_helper_start;
810
811	memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
812
813	/*
814	 * vectors + 0xfe0 = __kuser_get_tls
815	 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8
816	 */
817	if (tls_emu || has_tls_reg)
818		memcpy(vectors + 0xfe0, vectors + 0xfe8, 4);
819}
820#else
821static inline void __init kuser_init(void *vectors)
822{
823}
824#endif
825
826void __init early_trap_init(void *vectors_base)
827{
828#ifndef CONFIG_CPU_V7M
829	unsigned long vectors = (unsigned long)vectors_base;
830	extern char __stubs_start[], __stubs_end[];
831	extern char __vectors_start[], __vectors_end[];
832	unsigned i;
833
834	vectors_page = vectors_base;
835
836	/*
837	 * Poison the vectors page with an undefined instruction.  This
838	 * instruction is chosen to be undefined for both ARM and Thumb
839	 * ISAs.  The Thumb version is an undefined instruction with a
840	 * branch back to the undefined instruction.
841	 */
842	for (i = 0; i < PAGE_SIZE / sizeof(u32); i++)
843		((u32 *)vectors_base)[i] = 0xe7fddef1;
844
845	/*
846	 * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
847	 * into the vector page, mapped at 0xffff0000, and ensure these
848	 * are visible to the instruction stream.
849	 */
850	memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
851	memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start);
852
853	kuser_init(vectors_base);
854
855	flush_icache_range(vectors, vectors + PAGE_SIZE * 2);
856#else /* ifndef CONFIG_CPU_V7M */
857	/*
858	 * on V7-M there is no need to copy the vector table to a dedicated
859	 * memory area. The address is configurable and so a table in the kernel
860	 * image can be used.
861	 */
862#endif
863}