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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/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#include <asm/opcodes.h>
38
39static const char *handler[]= {
40 "prefetch abort",
41 "data abort",
42 "address exception",
43 "interrupt",
44 "undefined instruction",
45};
46
47void *vectors_page;
48
49#ifdef CONFIG_DEBUG_USER
50unsigned int user_debug;
51
52static int __init user_debug_setup(char *str)
53{
54 get_option(&str, &user_debug);
55 return 1;
56}
57__setup("user_debug=", user_debug_setup);
58#endif
59
60static void dump_mem(const char *, const char *, unsigned long, unsigned long);
61
62void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame)
63{
64#ifdef CONFIG_KALLSYMS
65 printk("[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from);
66#else
67 printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
68#endif
69
70 if (in_exception_text(where))
71 dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs));
72}
73
74#ifndef CONFIG_ARM_UNWIND
75/*
76 * Stack pointers should always be within the kernels view of
77 * physical memory. If it is not there, then we can't dump
78 * out any information relating to the stack.
79 */
80static int verify_stack(unsigned long sp)
81{
82 if (sp < PAGE_OFFSET ||
83 (sp > (unsigned long)high_memory && high_memory != NULL))
84 return -EFAULT;
85
86 return 0;
87}
88#endif
89
90/*
91 * Dump out the contents of some memory nicely...
92 */
93static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
94 unsigned long top)
95{
96 unsigned long first;
97 mm_segment_t fs;
98 int i;
99
100 /*
101 * We need to switch to kernel mode so that we can use __get_user
102 * to safely read from kernel space. Note that we now dump the
103 * code first, just in case the backtrace kills us.
104 */
105 fs = get_fs();
106 set_fs(KERNEL_DS);
107
108 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top);
109
110 for (first = bottom & ~31; first < top; first += 32) {
111 unsigned long p;
112 char str[sizeof(" 12345678") * 8 + 1];
113
114 memset(str, ' ', sizeof(str));
115 str[sizeof(str) - 1] = '\0';
116
117 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
118 if (p >= bottom && p < top) {
119 unsigned long val;
120 if (__get_user(val, (unsigned long *)p) == 0)
121 sprintf(str + i * 9, " %08lx", val);
122 else
123 sprintf(str + i * 9, " ????????");
124 }
125 }
126 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
127 }
128
129 set_fs(fs);
130}
131
132static void dump_instr(const char *lvl, struct pt_regs *regs)
133{
134 unsigned long addr = instruction_pointer(regs);
135 const int thumb = thumb_mode(regs);
136 const int width = thumb ? 4 : 8;
137 mm_segment_t fs;
138 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
139 int i;
140
141 /*
142 * We need to switch to kernel mode so that we can use __get_user
143 * to safely read from kernel space. Note that we now dump the
144 * code first, just in case the backtrace kills us.
145 */
146 fs = get_fs();
147 set_fs(KERNEL_DS);
148
149 for (i = -4; i < 1 + !!thumb; i++) {
150 unsigned int val, bad;
151
152 if (thumb)
153 bad = __get_user(val, &((u16 *)addr)[i]);
154 else
155 bad = __get_user(val, &((u32 *)addr)[i]);
156
157 if (!bad)
158 p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ",
159 width, val);
160 else {
161 p += sprintf(p, "bad PC value");
162 break;
163 }
164 }
165 printk("%sCode: %s\n", lvl, str);
166
167 set_fs(fs);
168}
169
170#ifdef CONFIG_ARM_UNWIND
171static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
172{
173 unwind_backtrace(regs, tsk);
174}
175#else
176static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
177{
178 unsigned int fp, mode;
179 int ok = 1;
180
181 printk("Backtrace: ");
182
183 if (!tsk)
184 tsk = current;
185
186 if (regs) {
187 fp = regs->ARM_fp;
188 mode = processor_mode(regs);
189 } else if (tsk != current) {
190 fp = thread_saved_fp(tsk);
191 mode = 0x10;
192 } else {
193 asm("mov %0, fp" : "=r" (fp) : : "cc");
194 mode = 0x10;
195 }
196
197 if (!fp) {
198 printk("no frame pointer");
199 ok = 0;
200 } else if (verify_stack(fp)) {
201 printk("invalid frame pointer 0x%08x", fp);
202 ok = 0;
203 } else if (fp < (unsigned long)end_of_stack(tsk))
204 printk("frame pointer underflow");
205 printk("\n");
206
207 if (ok)
208 c_backtrace(fp, mode);
209}
210#endif
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#ifdef CONFIG_THUMB2_KERNEL
229#define S_ISA " THUMB2"
230#else
231#define S_ISA " ARM"
232#endif
233
234static int __die(const char *str, int err, struct pt_regs *regs)
235{
236 struct task_struct *tsk = current;
237 static int die_counter;
238 int ret;
239
240 printk(KERN_EMERG "Internal error: %s: %x [#%d]" S_PREEMPT S_SMP
241 S_ISA "\n", str, err, ++die_counter);
242
243 /* trap and error numbers are mostly meaningless on ARM */
244 ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV);
245 if (ret == NOTIFY_STOP)
246 return 1;
247
248 print_modules();
249 __show_regs(regs);
250 printk(KERN_EMERG "Process %.*s (pid: %d, stack limit = 0x%p)\n",
251 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk));
252
253 if (!user_mode(regs) || in_interrupt()) {
254 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp,
255 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
256 dump_backtrace(regs, tsk);
257 dump_instr(KERN_EMERG, regs);
258 }
259
260 return 0;
261}
262
263static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
264static int die_owner = -1;
265static unsigned int die_nest_count;
266
267static unsigned long oops_begin(void)
268{
269 int cpu;
270 unsigned long flags;
271
272 oops_enter();
273
274 /* racy, but better than risking deadlock. */
275 raw_local_irq_save(flags);
276 cpu = smp_processor_id();
277 if (!arch_spin_trylock(&die_lock)) {
278 if (cpu == die_owner)
279 /* nested oops. should stop eventually */;
280 else
281 arch_spin_lock(&die_lock);
282 }
283 die_nest_count++;
284 die_owner = cpu;
285 console_verbose();
286 bust_spinlocks(1);
287 return flags;
288}
289
290static void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
291{
292 if (regs && kexec_should_crash(current))
293 crash_kexec(regs);
294
295 bust_spinlocks(0);
296 die_owner = -1;
297 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
298 die_nest_count--;
299 if (!die_nest_count)
300 /* Nest count reaches zero, release the lock. */
301 arch_spin_unlock(&die_lock);
302 raw_local_irq_restore(flags);
303 oops_exit();
304
305 if (in_interrupt())
306 panic("Fatal exception in interrupt");
307 if (panic_on_oops)
308 panic("Fatal exception");
309 if (signr)
310 do_exit(signr);
311}
312
313/*
314 * This function is protected against re-entrancy.
315 */
316void die(const char *str, struct pt_regs *regs, int err)
317{
318 enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE;
319 unsigned long flags = oops_begin();
320 int sig = SIGSEGV;
321
322 if (!user_mode(regs))
323 bug_type = report_bug(regs->ARM_pc, regs);
324 if (bug_type != BUG_TRAP_TYPE_NONE)
325 str = "Oops - BUG";
326
327 if (__die(str, err, regs))
328 sig = 0;
329
330 oops_end(flags, regs, sig);
331}
332
333void arm_notify_die(const char *str, struct pt_regs *regs,
334 struct siginfo *info, unsigned long err, unsigned long trap)
335{
336 if (user_mode(regs)) {
337 current->thread.error_code = err;
338 current->thread.trap_no = trap;
339
340 force_sig_info(info->si_signo, info, current);
341 } else {
342 die(str, regs, err);
343 }
344}
345
346#ifdef CONFIG_GENERIC_BUG
347
348int is_valid_bugaddr(unsigned long pc)
349{
350#ifdef CONFIG_THUMB2_KERNEL
351 u16 bkpt;
352 u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE);
353#else
354 u32 bkpt;
355 u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE);
356#endif
357
358 if (probe_kernel_address((unsigned *)pc, bkpt))
359 return 0;
360
361 return bkpt == insn;
362}
363
364#endif
365
366static LIST_HEAD(undef_hook);
367static DEFINE_RAW_SPINLOCK(undef_lock);
368
369void register_undef_hook(struct undef_hook *hook)
370{
371 unsigned long flags;
372
373 raw_spin_lock_irqsave(&undef_lock, flags);
374 list_add(&hook->node, &undef_hook);
375 raw_spin_unlock_irqrestore(&undef_lock, flags);
376}
377
378void unregister_undef_hook(struct undef_hook *hook)
379{
380 unsigned long flags;
381
382 raw_spin_lock_irqsave(&undef_lock, flags);
383 list_del(&hook->node);
384 raw_spin_unlock_irqrestore(&undef_lock, flags);
385}
386
387static int call_undef_hook(struct pt_regs *regs, unsigned int instr)
388{
389 struct undef_hook *hook;
390 unsigned long flags;
391 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL;
392
393 raw_spin_lock_irqsave(&undef_lock, flags);
394 list_for_each_entry(hook, &undef_hook, node)
395 if ((instr & hook->instr_mask) == hook->instr_val &&
396 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val)
397 fn = hook->fn;
398 raw_spin_unlock_irqrestore(&undef_lock, flags);
399
400 return fn ? fn(regs, instr) : 1;
401}
402
403asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
404{
405 unsigned int instr;
406 siginfo_t info;
407 void __user *pc;
408
409 pc = (void __user *)instruction_pointer(regs);
410
411 if (processor_mode(regs) == SVC_MODE) {
412#ifdef CONFIG_THUMB2_KERNEL
413 if (thumb_mode(regs)) {
414 instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]);
415 if (is_wide_instruction(instr)) {
416 u16 inst2;
417 inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]);
418 instr = __opcode_thumb32_compose(instr, inst2);
419 }
420 } else
421#endif
422 instr = __mem_to_opcode_arm(*(u32 *) pc);
423 } else if (thumb_mode(regs)) {
424 if (get_user(instr, (u16 __user *)pc))
425 goto die_sig;
426 instr = __mem_to_opcode_thumb16(instr);
427 if (is_wide_instruction(instr)) {
428 unsigned int instr2;
429 if (get_user(instr2, (u16 __user *)pc+1))
430 goto die_sig;
431 instr2 = __mem_to_opcode_thumb16(instr2);
432 instr = __opcode_thumb32_compose(instr, instr2);
433 }
434 } else {
435 if (get_user(instr, (u32 __user *)pc))
436 goto die_sig;
437 instr = __mem_to_opcode_arm(instr);
438 }
439
440 if (call_undef_hook(regs, instr) == 0)
441 return;
442
443die_sig:
444#ifdef CONFIG_DEBUG_USER
445 if (user_debug & UDBG_UNDEFINED) {
446 printk(KERN_INFO "%s (%d): undefined instruction: pc=%p\n",
447 current->comm, task_pid_nr(current), pc);
448 __show_regs(regs);
449 dump_instr(KERN_INFO, regs);
450 }
451#endif
452
453 info.si_signo = SIGILL;
454 info.si_errno = 0;
455 info.si_code = ILL_ILLOPC;
456 info.si_addr = pc;
457
458 arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6);
459}
460
461asmlinkage void do_unexp_fiq (struct pt_regs *regs)
462{
463 printk("Hmm. Unexpected FIQ received, but trying to continue\n");
464 printk("You may have a hardware problem...\n");
465}
466
467/*
468 * bad_mode handles the impossible case in the vectors. If you see one of
469 * these, then it's extremely serious, and could mean you have buggy hardware.
470 * It never returns, and never tries to sync. We hope that we can at least
471 * dump out some state information...
472 */
473asmlinkage void bad_mode(struct pt_regs *regs, int reason)
474{
475 console_verbose();
476
477 printk(KERN_CRIT "Bad mode in %s handler detected\n", handler[reason]);
478
479 die("Oops - bad mode", regs, 0);
480 local_irq_disable();
481 panic("bad mode");
482}
483
484static int bad_syscall(int n, struct pt_regs *regs)
485{
486 struct thread_info *thread = current_thread_info();
487 siginfo_t info;
488
489 if ((current->personality & PER_MASK) != PER_LINUX &&
490 thread->exec_domain->handler) {
491 thread->exec_domain->handler(n, regs);
492 return regs->ARM_r0;
493 }
494
495#ifdef CONFIG_DEBUG_USER
496 if (user_debug & UDBG_SYSCALL) {
497 printk(KERN_ERR "[%d] %s: obsolete system call %08x.\n",
498 task_pid_nr(current), current->comm, n);
499 dump_instr(KERN_ERR, regs);
500 }
501#endif
502
503 info.si_signo = SIGILL;
504 info.si_errno = 0;
505 info.si_code = ILL_ILLTRP;
506 info.si_addr = (void __user *)instruction_pointer(regs) -
507 (thumb_mode(regs) ? 2 : 4);
508
509 arm_notify_die("Oops - bad syscall", regs, &info, n, 0);
510
511 return regs->ARM_r0;
512}
513
514static long do_cache_op_restart(struct restart_block *);
515
516static inline int
517__do_cache_op(unsigned long start, unsigned long end)
518{
519 int ret;
520
521 do {
522 unsigned long chunk = min(PAGE_SIZE, end - start);
523
524 if (signal_pending(current)) {
525 struct thread_info *ti = current_thread_info();
526
527 ti->restart_block = (struct restart_block) {
528 .fn = do_cache_op_restart,
529 };
530
531 ti->arm_restart_block = (struct arm_restart_block) {
532 {
533 .cache = {
534 .start = start,
535 .end = end,
536 },
537 },
538 };
539
540 return -ERESTART_RESTARTBLOCK;
541 }
542
543 ret = flush_cache_user_range(start, start + chunk);
544 if (ret)
545 return ret;
546
547 cond_resched();
548 start += chunk;
549 } while (start < end);
550
551 return 0;
552}
553
554static long do_cache_op_restart(struct restart_block *unused)
555{
556 struct arm_restart_block *restart_block;
557
558 restart_block = ¤t_thread_info()->arm_restart_block;
559 return __do_cache_op(restart_block->cache.start,
560 restart_block->cache.end);
561}
562
563static inline int
564do_cache_op(unsigned long start, unsigned long end, int flags)
565{
566 if (end < start || flags)
567 return -EINVAL;
568
569 if (!access_ok(VERIFY_READ, start, end - start))
570 return -EFAULT;
571
572 return __do_cache_op(start, end);
573}
574
575/*
576 * Handle all unrecognised system calls.
577 * 0x9f0000 - 0x9fffff are some more esoteric system calls
578 */
579#define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
580asmlinkage int arm_syscall(int no, struct pt_regs *regs)
581{
582 struct thread_info *thread = current_thread_info();
583 siginfo_t info;
584
585 if ((no >> 16) != (__ARM_NR_BASE>> 16))
586 return bad_syscall(no, regs);
587
588 switch (no & 0xffff) {
589 case 0: /* branch through 0 */
590 info.si_signo = SIGSEGV;
591 info.si_errno = 0;
592 info.si_code = SEGV_MAPERR;
593 info.si_addr = NULL;
594
595 arm_notify_die("branch through zero", regs, &info, 0, 0);
596 return 0;
597
598 case NR(breakpoint): /* SWI BREAK_POINT */
599 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
600 ptrace_break(current, regs);
601 return regs->ARM_r0;
602
603 /*
604 * Flush a region from virtual address 'r0' to virtual address 'r1'
605 * _exclusive_. There is no alignment requirement on either address;
606 * user space does not need to know the hardware cache layout.
607 *
608 * r2 contains flags. It should ALWAYS be passed as ZERO until it
609 * is defined to be something else. For now we ignore it, but may
610 * the fires of hell burn in your belly if you break this rule. ;)
611 *
612 * (at a later date, we may want to allow this call to not flush
613 * various aspects of the cache. Passing '0' will guarantee that
614 * everything necessary gets flushed to maintain consistency in
615 * the specified region).
616 */
617 case NR(cacheflush):
618 return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
619
620 case NR(usr26):
621 if (!(elf_hwcap & HWCAP_26BIT))
622 break;
623 regs->ARM_cpsr &= ~MODE32_BIT;
624 return regs->ARM_r0;
625
626 case NR(usr32):
627 if (!(elf_hwcap & HWCAP_26BIT))
628 break;
629 regs->ARM_cpsr |= MODE32_BIT;
630 return regs->ARM_r0;
631
632 case NR(set_tls):
633 thread->tp_value[0] = regs->ARM_r0;
634 if (tls_emu)
635 return 0;
636 if (has_tls_reg) {
637 asm ("mcr p15, 0, %0, c13, c0, 3"
638 : : "r" (regs->ARM_r0));
639 } else {
640 /*
641 * User space must never try to access this directly.
642 * Expect your app to break eventually if you do so.
643 * The user helper at 0xffff0fe0 must be used instead.
644 * (see entry-armv.S for details)
645 */
646 *((unsigned int *)0xffff0ff0) = regs->ARM_r0;
647 }
648 return 0;
649
650#ifdef CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG
651 /*
652 * Atomically store r1 in *r2 if *r2 is equal to r0 for user space.
653 * Return zero in r0 if *MEM was changed or non-zero if no exchange
654 * happened. Also set the user C flag accordingly.
655 * If access permissions have to be fixed up then non-zero is
656 * returned and the operation has to be re-attempted.
657 *
658 * *NOTE*: This is a ghost syscall private to the kernel. Only the
659 * __kuser_cmpxchg code in entry-armv.S should be aware of its
660 * existence. Don't ever use this from user code.
661 */
662 case NR(cmpxchg):
663 for (;;) {
664 extern void do_DataAbort(unsigned long addr, unsigned int fsr,
665 struct pt_regs *regs);
666 unsigned long val;
667 unsigned long addr = regs->ARM_r2;
668 struct mm_struct *mm = current->mm;
669 pgd_t *pgd; pmd_t *pmd; pte_t *pte;
670 spinlock_t *ptl;
671
672 regs->ARM_cpsr &= ~PSR_C_BIT;
673 down_read(&mm->mmap_sem);
674 pgd = pgd_offset(mm, addr);
675 if (!pgd_present(*pgd))
676 goto bad_access;
677 pmd = pmd_offset(pgd, addr);
678 if (!pmd_present(*pmd))
679 goto bad_access;
680 pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
681 if (!pte_present(*pte) || !pte_write(*pte) || !pte_dirty(*pte)) {
682 pte_unmap_unlock(pte, ptl);
683 goto bad_access;
684 }
685 val = *(unsigned long *)addr;
686 val -= regs->ARM_r0;
687 if (val == 0) {
688 *(unsigned long *)addr = regs->ARM_r1;
689 regs->ARM_cpsr |= PSR_C_BIT;
690 }
691 pte_unmap_unlock(pte, ptl);
692 up_read(&mm->mmap_sem);
693 return val;
694
695 bad_access:
696 up_read(&mm->mmap_sem);
697 /* simulate a write access fault */
698 do_DataAbort(addr, 15 + (1 << 11), regs);
699 }
700#endif
701
702 default:
703 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS
704 if not implemented, rather than raising SIGILL. This
705 way the calling program can gracefully determine whether
706 a feature is supported. */
707 if ((no & 0xffff) <= 0x7ff)
708 return -ENOSYS;
709 break;
710 }
711#ifdef CONFIG_DEBUG_USER
712 /*
713 * experience shows that these seem to indicate that
714 * something catastrophic has happened
715 */
716 if (user_debug & UDBG_SYSCALL) {
717 printk("[%d] %s: arm syscall %d\n",
718 task_pid_nr(current), current->comm, no);
719 dump_instr("", regs);
720 if (user_mode(regs)) {
721 __show_regs(regs);
722 c_backtrace(regs->ARM_fp, processor_mode(regs));
723 }
724 }
725#endif
726 info.si_signo = SIGILL;
727 info.si_errno = 0;
728 info.si_code = ILL_ILLTRP;
729 info.si_addr = (void __user *)instruction_pointer(regs) -
730 (thumb_mode(regs) ? 2 : 4);
731
732 arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0);
733 return 0;
734}
735
736#ifdef CONFIG_TLS_REG_EMUL
737
738/*
739 * We might be running on an ARMv6+ processor which should have the TLS
740 * register but for some reason we can't use it, or maybe an SMP system
741 * using a pre-ARMv6 processor (there are apparently a few prototypes like
742 * that in existence) and therefore access to that register must be
743 * emulated.
744 */
745
746static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
747{
748 int reg = (instr >> 12) & 15;
749 if (reg == 15)
750 return 1;
751 regs->uregs[reg] = current_thread_info()->tp_value[0];
752 regs->ARM_pc += 4;
753 return 0;
754}
755
756static struct undef_hook arm_mrc_hook = {
757 .instr_mask = 0x0fff0fff,
758 .instr_val = 0x0e1d0f70,
759 .cpsr_mask = PSR_T_BIT,
760 .cpsr_val = 0,
761 .fn = get_tp_trap,
762};
763
764static int __init arm_mrc_hook_init(void)
765{
766 register_undef_hook(&arm_mrc_hook);
767 return 0;
768}
769
770late_initcall(arm_mrc_hook_init);
771
772#endif
773
774void __bad_xchg(volatile void *ptr, int size)
775{
776 printk("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n",
777 __builtin_return_address(0), ptr, size);
778 BUG();
779}
780EXPORT_SYMBOL(__bad_xchg);
781
782/*
783 * A data abort trap was taken, but we did not handle the instruction.
784 * Try to abort the user program, or panic if it was the kernel.
785 */
786asmlinkage void
787baddataabort(int code, unsigned long instr, struct pt_regs *regs)
788{
789 unsigned long addr = instruction_pointer(regs);
790 siginfo_t info;
791
792#ifdef CONFIG_DEBUG_USER
793 if (user_debug & UDBG_BADABORT) {
794 printk(KERN_ERR "[%d] %s: bad data abort: code %d instr 0x%08lx\n",
795 task_pid_nr(current), current->comm, code, instr);
796 dump_instr(KERN_ERR, regs);
797 show_pte(current->mm, addr);
798 }
799#endif
800
801 info.si_signo = SIGILL;
802 info.si_errno = 0;
803 info.si_code = ILL_ILLOPC;
804 info.si_addr = (void __user *)addr;
805
806 arm_notify_die("unknown data abort code", regs, &info, instr, 0);
807}
808
809void __readwrite_bug(const char *fn)
810{
811 printk("%s called, but not implemented\n", fn);
812 BUG();
813}
814EXPORT_SYMBOL(__readwrite_bug);
815
816void __pte_error(const char *file, int line, pte_t pte)
817{
818 printk("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte));
819}
820
821void __pmd_error(const char *file, int line, pmd_t pmd)
822{
823 printk("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd));
824}
825
826void __pgd_error(const char *file, int line, pgd_t pgd)
827{
828 printk("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd));
829}
830
831asmlinkage void __div0(void)
832{
833 printk("Division by zero in kernel.\n");
834 dump_stack();
835}
836EXPORT_SYMBOL(__div0);
837
838void abort(void)
839{
840 BUG();
841
842 /* if that doesn't kill us, halt */
843 panic("Oops failed to kill thread");
844}
845EXPORT_SYMBOL(abort);
846
847void __init trap_init(void)
848{
849 return;
850}
851
852#ifdef CONFIG_KUSER_HELPERS
853static void __init kuser_init(void *vectors)
854{
855 extern char __kuser_helper_start[], __kuser_helper_end[];
856 int kuser_sz = __kuser_helper_end - __kuser_helper_start;
857
858 memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
859
860 /*
861 * vectors + 0xfe0 = __kuser_get_tls
862 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8
863 */
864 if (tls_emu || has_tls_reg)
865 memcpy(vectors + 0xfe0, vectors + 0xfe8, 4);
866}
867#else
868static inline void __init kuser_init(void *vectors)
869{
870}
871#endif
872
873void __init early_trap_init(void *vectors_base)
874{
875#ifndef CONFIG_CPU_V7M
876 unsigned long vectors = (unsigned long)vectors_base;
877 extern char __stubs_start[], __stubs_end[];
878 extern char __vectors_start[], __vectors_end[];
879 unsigned i;
880
881 vectors_page = vectors_base;
882
883 /*
884 * Poison the vectors page with an undefined instruction. This
885 * instruction is chosen to be undefined for both ARM and Thumb
886 * ISAs. The Thumb version is an undefined instruction with a
887 * branch back to the undefined instruction.
888 */
889 for (i = 0; i < PAGE_SIZE / sizeof(u32); i++)
890 ((u32 *)vectors_base)[i] = 0xe7fddef1;
891
892 /*
893 * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
894 * into the vector page, mapped at 0xffff0000, and ensure these
895 * are visible to the instruction stream.
896 */
897 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
898 memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start);
899
900 kuser_init(vectors_base);
901
902 flush_icache_range(vectors, vectors + PAGE_SIZE * 2);
903 modify_domain(DOMAIN_USER, DOMAIN_CLIENT);
904#else /* ifndef CONFIG_CPU_V7M */
905 /*
906 * on V7-M there is no need to copy the vector table to a dedicated
907 * memory area. The address is configurable and so a table in the kernel
908 * image can be used.
909 */
910#endif
911}
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#include <linux/irq.h>
29
30#include <linux/atomic.h>
31#include <asm/cacheflush.h>
32#include <asm/exception.h>
33#include <asm/unistd.h>
34#include <asm/traps.h>
35#include <asm/ptrace.h>
36#include <asm/unwind.h>
37#include <asm/tls.h>
38#include <asm/system_misc.h>
39#include <asm/opcodes.h>
40
41
42static const char *handler[]= {
43 "prefetch abort",
44 "data abort",
45 "address exception",
46 "interrupt",
47 "undefined instruction",
48};
49
50void *vectors_page;
51
52#ifdef CONFIG_DEBUG_USER
53unsigned int user_debug;
54
55static int __init user_debug_setup(char *str)
56{
57 get_option(&str, &user_debug);
58 return 1;
59}
60__setup("user_debug=", user_debug_setup);
61#endif
62
63static void dump_mem(const char *, const char *, unsigned long, unsigned long);
64
65void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame)
66{
67#ifdef CONFIG_KALLSYMS
68 printk("[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from);
69#else
70 printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
71#endif
72
73 if (in_exception_text(where))
74 dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs));
75}
76
77#ifndef CONFIG_ARM_UNWIND
78/*
79 * Stack pointers should always be within the kernels view of
80 * physical memory. If it is not there, then we can't dump
81 * out any information relating to the stack.
82 */
83static int verify_stack(unsigned long sp)
84{
85 if (sp < PAGE_OFFSET ||
86 (sp > (unsigned long)high_memory && high_memory != NULL))
87 return -EFAULT;
88
89 return 0;
90}
91#endif
92
93/*
94 * Dump out the contents of some memory nicely...
95 */
96static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
97 unsigned long top)
98{
99 unsigned long first;
100 mm_segment_t fs;
101 int i;
102
103 /*
104 * We need to switch to kernel mode so that we can use __get_user
105 * to safely read from kernel space. Note that we now dump the
106 * code first, just in case the backtrace kills us.
107 */
108 fs = get_fs();
109 set_fs(KERNEL_DS);
110
111 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top);
112
113 for (first = bottom & ~31; first < top; first += 32) {
114 unsigned long p;
115 char str[sizeof(" 12345678") * 8 + 1];
116
117 memset(str, ' ', sizeof(str));
118 str[sizeof(str) - 1] = '\0';
119
120 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
121 if (p >= bottom && p < top) {
122 unsigned long val;
123 if (__get_user(val, (unsigned long *)p) == 0)
124 sprintf(str + i * 9, " %08lx", val);
125 else
126 sprintf(str + i * 9, " ????????");
127 }
128 }
129 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
130 }
131
132 set_fs(fs);
133}
134
135static void dump_instr(const char *lvl, struct pt_regs *regs)
136{
137 unsigned long addr = instruction_pointer(regs);
138 const int thumb = thumb_mode(regs);
139 const int width = thumb ? 4 : 8;
140 mm_segment_t fs;
141 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
142 int i;
143
144 /*
145 * We need to switch to kernel mode so that we can use __get_user
146 * to safely read from kernel space. Note that we now dump the
147 * code first, just in case the backtrace kills us.
148 */
149 fs = get_fs();
150 set_fs(KERNEL_DS);
151
152 for (i = -4; i < 1 + !!thumb; i++) {
153 unsigned int val, bad;
154
155 if (thumb)
156 bad = __get_user(val, &((u16 *)addr)[i]);
157 else
158 bad = __get_user(val, &((u32 *)addr)[i]);
159
160 if (!bad)
161 p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ",
162 width, val);
163 else {
164 p += sprintf(p, "bad PC value");
165 break;
166 }
167 }
168 printk("%sCode: %s\n", lvl, str);
169
170 set_fs(fs);
171}
172
173#ifdef CONFIG_ARM_UNWIND
174static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
175{
176 unwind_backtrace(regs, tsk);
177}
178#else
179static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
180{
181 unsigned int fp, mode;
182 int ok = 1;
183
184 printk("Backtrace: ");
185
186 if (!tsk)
187 tsk = current;
188
189 if (regs) {
190 fp = frame_pointer(regs);
191 mode = processor_mode(regs);
192 } else if (tsk != current) {
193 fp = thread_saved_fp(tsk);
194 mode = 0x10;
195 } else {
196 asm("mov %0, fp" : "=r" (fp) : : "cc");
197 mode = 0x10;
198 }
199
200 if (!fp) {
201 pr_cont("no frame pointer");
202 ok = 0;
203 } else if (verify_stack(fp)) {
204 pr_cont("invalid frame pointer 0x%08x", fp);
205 ok = 0;
206 } else if (fp < (unsigned long)end_of_stack(tsk))
207 pr_cont("frame pointer underflow");
208 pr_cont("\n");
209
210 if (ok)
211 c_backtrace(fp, mode);
212}
213#endif
214
215void show_stack(struct task_struct *tsk, unsigned long *sp)
216{
217 dump_backtrace(NULL, tsk);
218 barrier();
219}
220
221#ifdef CONFIG_PREEMPT
222#define S_PREEMPT " PREEMPT"
223#else
224#define S_PREEMPT ""
225#endif
226#ifdef CONFIG_SMP
227#define S_SMP " SMP"
228#else
229#define S_SMP ""
230#endif
231#ifdef CONFIG_THUMB2_KERNEL
232#define S_ISA " THUMB2"
233#else
234#define S_ISA " ARM"
235#endif
236
237static int __die(const char *str, int err, struct pt_regs *regs)
238{
239 struct task_struct *tsk = current;
240 static int die_counter;
241 int ret;
242
243 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP S_ISA "\n",
244 str, err, ++die_counter);
245
246 /* trap and error numbers are mostly meaningless on ARM */
247 ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV);
248 if (ret == NOTIFY_STOP)
249 return 1;
250
251 print_modules();
252 __show_regs(regs);
253 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
254 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk));
255
256 if (!user_mode(regs) || in_interrupt()) {
257 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp,
258 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
259 dump_backtrace(regs, tsk);
260 dump_instr(KERN_EMERG, regs);
261 }
262
263 return 0;
264}
265
266static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
267static int die_owner = -1;
268static unsigned int die_nest_count;
269
270static unsigned long oops_begin(void)
271{
272 int cpu;
273 unsigned long flags;
274
275 oops_enter();
276
277 /* racy, but better than risking deadlock. */
278 raw_local_irq_save(flags);
279 cpu = smp_processor_id();
280 if (!arch_spin_trylock(&die_lock)) {
281 if (cpu == die_owner)
282 /* nested oops. should stop eventually */;
283 else
284 arch_spin_lock(&die_lock);
285 }
286 die_nest_count++;
287 die_owner = cpu;
288 console_verbose();
289 bust_spinlocks(1);
290 return flags;
291}
292
293static void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
294{
295 if (regs && kexec_should_crash(current))
296 crash_kexec(regs);
297
298 bust_spinlocks(0);
299 die_owner = -1;
300 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
301 die_nest_count--;
302 if (!die_nest_count)
303 /* Nest count reaches zero, release the lock. */
304 arch_spin_unlock(&die_lock);
305 raw_local_irq_restore(flags);
306 oops_exit();
307
308 if (in_interrupt())
309 panic("Fatal exception in interrupt");
310 if (panic_on_oops)
311 panic("Fatal exception");
312 if (signr)
313 do_exit(signr);
314}
315
316/*
317 * This function is protected against re-entrancy.
318 */
319void die(const char *str, struct pt_regs *regs, int err)
320{
321 enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE;
322 unsigned long flags = oops_begin();
323 int sig = SIGSEGV;
324
325 if (!user_mode(regs))
326 bug_type = report_bug(regs->ARM_pc, regs);
327 if (bug_type != BUG_TRAP_TYPE_NONE)
328 str = "Oops - BUG";
329
330 if (__die(str, err, regs))
331 sig = 0;
332
333 oops_end(flags, regs, sig);
334}
335
336void arm_notify_die(const char *str, struct pt_regs *regs,
337 struct siginfo *info, unsigned long err, unsigned long trap)
338{
339 if (user_mode(regs)) {
340 current->thread.error_code = err;
341 current->thread.trap_no = trap;
342
343 force_sig_info(info->si_signo, info, current);
344 } else {
345 die(str, regs, err);
346 }
347}
348
349#ifdef CONFIG_GENERIC_BUG
350
351int is_valid_bugaddr(unsigned long pc)
352{
353#ifdef CONFIG_THUMB2_KERNEL
354 u16 bkpt;
355 u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE);
356#else
357 u32 bkpt;
358 u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE);
359#endif
360
361 if (probe_kernel_address((unsigned *)pc, bkpt))
362 return 0;
363
364 return bkpt == insn;
365}
366
367#endif
368
369static LIST_HEAD(undef_hook);
370static DEFINE_RAW_SPINLOCK(undef_lock);
371
372void register_undef_hook(struct undef_hook *hook)
373{
374 unsigned long flags;
375
376 raw_spin_lock_irqsave(&undef_lock, flags);
377 list_add(&hook->node, &undef_hook);
378 raw_spin_unlock_irqrestore(&undef_lock, flags);
379}
380
381void unregister_undef_hook(struct undef_hook *hook)
382{
383 unsigned long flags;
384
385 raw_spin_lock_irqsave(&undef_lock, flags);
386 list_del(&hook->node);
387 raw_spin_unlock_irqrestore(&undef_lock, flags);
388}
389
390static int call_undef_hook(struct pt_regs *regs, unsigned int instr)
391{
392 struct undef_hook *hook;
393 unsigned long flags;
394 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL;
395
396 raw_spin_lock_irqsave(&undef_lock, flags);
397 list_for_each_entry(hook, &undef_hook, node)
398 if ((instr & hook->instr_mask) == hook->instr_val &&
399 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val)
400 fn = hook->fn;
401 raw_spin_unlock_irqrestore(&undef_lock, flags);
402
403 return fn ? fn(regs, instr) : 1;
404}
405
406asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
407{
408 unsigned int instr;
409 siginfo_t info;
410 void __user *pc;
411
412 pc = (void __user *)instruction_pointer(regs);
413
414 if (processor_mode(regs) == SVC_MODE) {
415#ifdef CONFIG_THUMB2_KERNEL
416 if (thumb_mode(regs)) {
417 instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]);
418 if (is_wide_instruction(instr)) {
419 u16 inst2;
420 inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]);
421 instr = __opcode_thumb32_compose(instr, inst2);
422 }
423 } else
424#endif
425 instr = __mem_to_opcode_arm(*(u32 *) pc);
426 } else if (thumb_mode(regs)) {
427 if (get_user(instr, (u16 __user *)pc))
428 goto die_sig;
429 instr = __mem_to_opcode_thumb16(instr);
430 if (is_wide_instruction(instr)) {
431 unsigned int instr2;
432 if (get_user(instr2, (u16 __user *)pc+1))
433 goto die_sig;
434 instr2 = __mem_to_opcode_thumb16(instr2);
435 instr = __opcode_thumb32_compose(instr, instr2);
436 }
437 } else {
438 if (get_user(instr, (u32 __user *)pc))
439 goto die_sig;
440 instr = __mem_to_opcode_arm(instr);
441 }
442
443 if (call_undef_hook(regs, instr) == 0)
444 return;
445
446die_sig:
447#ifdef CONFIG_DEBUG_USER
448 if (user_debug & UDBG_UNDEFINED) {
449 pr_info("%s (%d): undefined instruction: pc=%p\n",
450 current->comm, task_pid_nr(current), pc);
451 __show_regs(regs);
452 dump_instr(KERN_INFO, regs);
453 }
454#endif
455
456 info.si_signo = SIGILL;
457 info.si_errno = 0;
458 info.si_code = ILL_ILLOPC;
459 info.si_addr = pc;
460
461 arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6);
462}
463
464/*
465 * Handle FIQ similarly to NMI on x86 systems.
466 *
467 * The runtime environment for NMIs is extremely restrictive
468 * (NMIs can pre-empt critical sections meaning almost all locking is
469 * forbidden) meaning this default FIQ handling must only be used in
470 * circumstances where non-maskability improves robustness, such as
471 * watchdog or debug logic.
472 *
473 * This handler is not appropriate for general purpose use in drivers
474 * platform code and can be overrideen using set_fiq_handler.
475 */
476asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs)
477{
478 struct pt_regs *old_regs = set_irq_regs(regs);
479
480 nmi_enter();
481
482 /* nop. FIQ handlers for special arch/arm features can be added here. */
483
484 nmi_exit();
485
486 set_irq_regs(old_regs);
487}
488
489/*
490 * bad_mode handles the impossible case in the vectors. If you see one of
491 * these, then it's extremely serious, and could mean you have buggy hardware.
492 * It never returns, and never tries to sync. We hope that we can at least
493 * dump out some state information...
494 */
495asmlinkage void bad_mode(struct pt_regs *regs, int reason)
496{
497 console_verbose();
498
499 pr_crit("Bad mode in %s handler detected\n", handler[reason]);
500
501 die("Oops - bad mode", regs, 0);
502 local_irq_disable();
503 panic("bad mode");
504}
505
506static int bad_syscall(int n, struct pt_regs *regs)
507{
508 siginfo_t info;
509
510 if ((current->personality & PER_MASK) != PER_LINUX) {
511 send_sig(SIGSEGV, current, 1);
512 return regs->ARM_r0;
513 }
514
515#ifdef CONFIG_DEBUG_USER
516 if (user_debug & UDBG_SYSCALL) {
517 pr_err("[%d] %s: obsolete system call %08x.\n",
518 task_pid_nr(current), current->comm, n);
519 dump_instr(KERN_ERR, regs);
520 }
521#endif
522
523 info.si_signo = SIGILL;
524 info.si_errno = 0;
525 info.si_code = ILL_ILLTRP;
526 info.si_addr = (void __user *)instruction_pointer(regs) -
527 (thumb_mode(regs) ? 2 : 4);
528
529 arm_notify_die("Oops - bad syscall", regs, &info, n, 0);
530
531 return regs->ARM_r0;
532}
533
534static inline int
535__do_cache_op(unsigned long start, unsigned long end)
536{
537 int ret;
538
539 do {
540 unsigned long chunk = min(PAGE_SIZE, end - start);
541
542 if (fatal_signal_pending(current))
543 return 0;
544
545 ret = flush_cache_user_range(start, start + chunk);
546 if (ret)
547 return ret;
548
549 cond_resched();
550 start += chunk;
551 } while (start < end);
552
553 return 0;
554}
555
556static inline int
557do_cache_op(unsigned long start, unsigned long end, int flags)
558{
559 if (end < start || flags)
560 return -EINVAL;
561
562 if (!access_ok(VERIFY_READ, start, end - start))
563 return -EFAULT;
564
565 return __do_cache_op(start, end);
566}
567
568/*
569 * Handle all unrecognised system calls.
570 * 0x9f0000 - 0x9fffff are some more esoteric system calls
571 */
572#define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
573asmlinkage int arm_syscall(int no, struct pt_regs *regs)
574{
575 siginfo_t info;
576
577 if ((no >> 16) != (__ARM_NR_BASE>> 16))
578 return bad_syscall(no, regs);
579
580 switch (no & 0xffff) {
581 case 0: /* branch through 0 */
582 info.si_signo = SIGSEGV;
583 info.si_errno = 0;
584 info.si_code = SEGV_MAPERR;
585 info.si_addr = NULL;
586
587 arm_notify_die("branch through zero", regs, &info, 0, 0);
588 return 0;
589
590 case NR(breakpoint): /* SWI BREAK_POINT */
591 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
592 ptrace_break(current, regs);
593 return regs->ARM_r0;
594
595 /*
596 * Flush a region from virtual address 'r0' to virtual address 'r1'
597 * _exclusive_. There is no alignment requirement on either address;
598 * user space does not need to know the hardware cache layout.
599 *
600 * r2 contains flags. It should ALWAYS be passed as ZERO until it
601 * is defined to be something else. For now we ignore it, but may
602 * the fires of hell burn in your belly if you break this rule. ;)
603 *
604 * (at a later date, we may want to allow this call to not flush
605 * various aspects of the cache. Passing '0' will guarantee that
606 * everything necessary gets flushed to maintain consistency in
607 * the specified region).
608 */
609 case NR(cacheflush):
610 return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
611
612 case NR(usr26):
613 if (!(elf_hwcap & HWCAP_26BIT))
614 break;
615 regs->ARM_cpsr &= ~MODE32_BIT;
616 return regs->ARM_r0;
617
618 case NR(usr32):
619 if (!(elf_hwcap & HWCAP_26BIT))
620 break;
621 regs->ARM_cpsr |= MODE32_BIT;
622 return regs->ARM_r0;
623
624 case NR(set_tls):
625 set_tls(regs->ARM_r0);
626 return 0;
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 pr_err("[%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(frame_pointer(regs), 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[0];
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
700/*
701 * A data abort trap was taken, but we did not handle the instruction.
702 * Try to abort the user program, or panic if it was the kernel.
703 */
704asmlinkage void
705baddataabort(int code, unsigned long instr, struct pt_regs *regs)
706{
707 unsigned long addr = instruction_pointer(regs);
708 siginfo_t info;
709
710#ifdef CONFIG_DEBUG_USER
711 if (user_debug & UDBG_BADABORT) {
712 pr_err("[%d] %s: bad data abort: code %d instr 0x%08lx\n",
713 task_pid_nr(current), current->comm, code, instr);
714 dump_instr(KERN_ERR, regs);
715 show_pte(current->mm, addr);
716 }
717#endif
718
719 info.si_signo = SIGILL;
720 info.si_errno = 0;
721 info.si_code = ILL_ILLOPC;
722 info.si_addr = (void __user *)addr;
723
724 arm_notify_die("unknown data abort code", regs, &info, instr, 0);
725}
726
727void __readwrite_bug(const char *fn)
728{
729 pr_err("%s called, but not implemented\n", fn);
730 BUG();
731}
732EXPORT_SYMBOL(__readwrite_bug);
733
734void __pte_error(const char *file, int line, pte_t pte)
735{
736 pr_err("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte));
737}
738
739void __pmd_error(const char *file, int line, pmd_t pmd)
740{
741 pr_err("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd));
742}
743
744void __pgd_error(const char *file, int line, pgd_t pgd)
745{
746 pr_err("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd));
747}
748
749asmlinkage void __div0(void)
750{
751 pr_err("Division by zero in kernel.\n");
752 dump_stack();
753}
754EXPORT_SYMBOL(__div0);
755
756void abort(void)
757{
758 BUG();
759
760 /* if that doesn't kill us, halt */
761 panic("Oops failed to kill thread");
762}
763EXPORT_SYMBOL(abort);
764
765void __init trap_init(void)
766{
767 return;
768}
769
770#ifdef CONFIG_KUSER_HELPERS
771static void __init kuser_init(void *vectors)
772{
773 extern char __kuser_helper_start[], __kuser_helper_end[];
774 int kuser_sz = __kuser_helper_end - __kuser_helper_start;
775
776 memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
777
778 /*
779 * vectors + 0xfe0 = __kuser_get_tls
780 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8
781 */
782 if (tls_emu || has_tls_reg)
783 memcpy(vectors + 0xfe0, vectors + 0xfe8, 4);
784}
785#else
786static inline void __init kuser_init(void *vectors)
787{
788}
789#endif
790
791void __init early_trap_init(void *vectors_base)
792{
793#ifndef CONFIG_CPU_V7M
794 unsigned long vectors = (unsigned long)vectors_base;
795 extern char __stubs_start[], __stubs_end[];
796 extern char __vectors_start[], __vectors_end[];
797 unsigned i;
798
799 vectors_page = vectors_base;
800
801 /*
802 * Poison the vectors page with an undefined instruction. This
803 * instruction is chosen to be undefined for both ARM and Thumb
804 * ISAs. The Thumb version is an undefined instruction with a
805 * branch back to the undefined instruction.
806 */
807 for (i = 0; i < PAGE_SIZE / sizeof(u32); i++)
808 ((u32 *)vectors_base)[i] = 0xe7fddef1;
809
810 /*
811 * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
812 * into the vector page, mapped at 0xffff0000, and ensure these
813 * are visible to the instruction stream.
814 */
815 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
816 memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start);
817
818 kuser_init(vectors_base);
819
820 flush_icache_range(vectors, vectors + PAGE_SIZE * 2);
821#else /* ifndef CONFIG_CPU_V7M */
822 /*
823 * on V7-M there is no need to copy the vector table to a dedicated
824 * memory area. The address is configurable and so a table in the kernel
825 * image can be used.
826 */
827#endif
828}