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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
38#include "signal.h"
39
40static const char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" };
41
42void *vectors_page;
43
44#ifdef CONFIG_DEBUG_USER
45unsigned int user_debug;
46
47static int __init user_debug_setup(char *str)
48{
49 get_option(&str, &user_debug);
50 return 1;
51}
52__setup("user_debug=", user_debug_setup);
53#endif
54
55static void dump_mem(const char *, const char *, unsigned long, unsigned long);
56
57void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame)
58{
59#ifdef CONFIG_KALLSYMS
60 printk("[<%08lx>] (%pS) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from);
61#else
62 printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
63#endif
64
65 if (in_exception_text(where))
66 dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs));
67}
68
69#ifndef CONFIG_ARM_UNWIND
70/*
71 * Stack pointers should always be within the kernels view of
72 * physical memory. If it is not there, then we can't dump
73 * out any information relating to the stack.
74 */
75static int verify_stack(unsigned long sp)
76{
77 if (sp < PAGE_OFFSET ||
78 (sp > (unsigned long)high_memory && high_memory != NULL))
79 return -EFAULT;
80
81 return 0;
82}
83#endif
84
85/*
86 * Dump out the contents of some memory nicely...
87 */
88static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
89 unsigned long top)
90{
91 unsigned long first;
92 mm_segment_t fs;
93 int i;
94
95 /*
96 * We need to switch to kernel mode so that we can use __get_user
97 * to safely read from kernel space. Note that we now dump the
98 * code first, just in case the backtrace kills us.
99 */
100 fs = get_fs();
101 set_fs(KERNEL_DS);
102
103 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top);
104
105 for (first = bottom & ~31; first < top; first += 32) {
106 unsigned long p;
107 char str[sizeof(" 12345678") * 8 + 1];
108
109 memset(str, ' ', sizeof(str));
110 str[sizeof(str) - 1] = '\0';
111
112 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
113 if (p >= bottom && p < top) {
114 unsigned long val;
115 if (__get_user(val, (unsigned long *)p) == 0)
116 sprintf(str + i * 9, " %08lx", val);
117 else
118 sprintf(str + i * 9, " ????????");
119 }
120 }
121 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
122 }
123
124 set_fs(fs);
125}
126
127static void dump_instr(const char *lvl, struct pt_regs *regs)
128{
129 unsigned long addr = instruction_pointer(regs);
130 const int thumb = thumb_mode(regs);
131 const int width = thumb ? 4 : 8;
132 mm_segment_t fs;
133 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
134 int i;
135
136 /*
137 * We need to switch to kernel mode so that we can use __get_user
138 * to safely read from kernel space. Note that we now dump the
139 * code first, just in case the backtrace kills us.
140 */
141 fs = get_fs();
142 set_fs(KERNEL_DS);
143
144 for (i = -4; i < 1 + !!thumb; i++) {
145 unsigned int val, bad;
146
147 if (thumb)
148 bad = __get_user(val, &((u16 *)addr)[i]);
149 else
150 bad = __get_user(val, &((u32 *)addr)[i]);
151
152 if (!bad)
153 p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ",
154 width, val);
155 else {
156 p += sprintf(p, "bad PC value");
157 break;
158 }
159 }
160 printk("%sCode: %s\n", lvl, str);
161
162 set_fs(fs);
163}
164
165#ifdef CONFIG_ARM_UNWIND
166static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
167{
168 unwind_backtrace(regs, tsk);
169}
170#else
171static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
172{
173 unsigned int fp, mode;
174 int ok = 1;
175
176 printk("Backtrace: ");
177
178 if (!tsk)
179 tsk = current;
180
181 if (regs) {
182 fp = regs->ARM_fp;
183 mode = processor_mode(regs);
184 } else if (tsk != current) {
185 fp = thread_saved_fp(tsk);
186 mode = 0x10;
187 } else {
188 asm("mov %0, fp" : "=r" (fp) : : "cc");
189 mode = 0x10;
190 }
191
192 if (!fp) {
193 printk("no frame pointer");
194 ok = 0;
195 } else if (verify_stack(fp)) {
196 printk("invalid frame pointer 0x%08x", fp);
197 ok = 0;
198 } else if (fp < (unsigned long)end_of_stack(tsk))
199 printk("frame pointer underflow");
200 printk("\n");
201
202 if (ok)
203 c_backtrace(fp, mode);
204}
205#endif
206
207void dump_stack(void)
208{
209 dump_backtrace(NULL, NULL);
210}
211
212EXPORT_SYMBOL(dump_stack);
213
214void show_stack(struct task_struct *tsk, unsigned long *sp)
215{
216 dump_backtrace(NULL, tsk);
217 barrier();
218}
219
220#ifdef CONFIG_PREEMPT
221#define S_PREEMPT " PREEMPT"
222#else
223#define S_PREEMPT ""
224#endif
225#ifdef CONFIG_SMP
226#define S_SMP " SMP"
227#else
228#define S_SMP ""
229#endif
230#ifdef CONFIG_THUMB2_KERNEL
231#define S_ISA " THUMB2"
232#else
233#define S_ISA " ARM"
234#endif
235
236static int __die(const char *str, int err, struct thread_info *thread, struct pt_regs *regs)
237{
238 struct task_struct *tsk = thread->task;
239 static int die_counter;
240 int ret;
241
242 printk(KERN_EMERG "Internal error: %s: %x [#%d]" S_PREEMPT S_SMP
243 S_ISA "\n", str, err, ++die_counter);
244
245 /* trap and error numbers are mostly meaningless on ARM */
246 ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV);
247 if (ret == NOTIFY_STOP)
248 return ret;
249
250 print_modules();
251 __show_regs(regs);
252 printk(KERN_EMERG "Process %.*s (pid: %d, stack limit = 0x%p)\n",
253 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1);
254
255 if (!user_mode(regs) || in_interrupt()) {
256 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp,
257 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
258 dump_backtrace(regs, tsk);
259 dump_instr(KERN_EMERG, regs);
260 }
261
262 return ret;
263}
264
265static DEFINE_RAW_SPINLOCK(die_lock);
266
267/*
268 * This function is protected against re-entrancy.
269 */
270void die(const char *str, struct pt_regs *regs, int err)
271{
272 struct thread_info *thread = current_thread_info();
273 int ret;
274 enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE;
275
276 oops_enter();
277
278 raw_spin_lock_irq(&die_lock);
279 console_verbose();
280 bust_spinlocks(1);
281 if (!user_mode(regs))
282 bug_type = report_bug(regs->ARM_pc, regs);
283 if (bug_type != BUG_TRAP_TYPE_NONE)
284 str = "Oops - BUG";
285 ret = __die(str, err, thread, regs);
286
287 if (regs && kexec_should_crash(thread->task))
288 crash_kexec(regs);
289
290 bust_spinlocks(0);
291 add_taint(TAINT_DIE);
292 raw_spin_unlock_irq(&die_lock);
293 oops_exit();
294
295 if (in_interrupt())
296 panic("Fatal exception in interrupt");
297 if (panic_on_oops)
298 panic("Fatal exception");
299 if (ret != NOTIFY_STOP)
300 do_exit(SIGSEGV);
301}
302
303void arm_notify_die(const char *str, struct pt_regs *regs,
304 struct siginfo *info, unsigned long err, unsigned long trap)
305{
306 if (user_mode(regs)) {
307 current->thread.error_code = err;
308 current->thread.trap_no = trap;
309
310 force_sig_info(info->si_signo, info, current);
311 } else {
312 die(str, regs, err);
313 }
314}
315
316#ifdef CONFIG_GENERIC_BUG
317
318int is_valid_bugaddr(unsigned long pc)
319{
320#ifdef CONFIG_THUMB2_KERNEL
321 unsigned short bkpt;
322#else
323 unsigned long bkpt;
324#endif
325
326 if (probe_kernel_address((unsigned *)pc, bkpt))
327 return 0;
328
329 return bkpt == BUG_INSTR_VALUE;
330}
331
332#endif
333
334static LIST_HEAD(undef_hook);
335static DEFINE_RAW_SPINLOCK(undef_lock);
336
337void register_undef_hook(struct undef_hook *hook)
338{
339 unsigned long flags;
340
341 raw_spin_lock_irqsave(&undef_lock, flags);
342 list_add(&hook->node, &undef_hook);
343 raw_spin_unlock_irqrestore(&undef_lock, flags);
344}
345
346void unregister_undef_hook(struct undef_hook *hook)
347{
348 unsigned long flags;
349
350 raw_spin_lock_irqsave(&undef_lock, flags);
351 list_del(&hook->node);
352 raw_spin_unlock_irqrestore(&undef_lock, flags);
353}
354
355static int call_undef_hook(struct pt_regs *regs, unsigned int instr)
356{
357 struct undef_hook *hook;
358 unsigned long flags;
359 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL;
360
361 raw_spin_lock_irqsave(&undef_lock, flags);
362 list_for_each_entry(hook, &undef_hook, node)
363 if ((instr & hook->instr_mask) == hook->instr_val &&
364 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val)
365 fn = hook->fn;
366 raw_spin_unlock_irqrestore(&undef_lock, flags);
367
368 return fn ? fn(regs, instr) : 1;
369}
370
371asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
372{
373 unsigned int instr;
374 siginfo_t info;
375 void __user *pc;
376
377 pc = (void __user *)instruction_pointer(regs);
378
379 if (processor_mode(regs) == SVC_MODE) {
380#ifdef CONFIG_THUMB2_KERNEL
381 if (thumb_mode(regs)) {
382 instr = ((u16 *)pc)[0];
383 if (is_wide_instruction(instr)) {
384 instr <<= 16;
385 instr |= ((u16 *)pc)[1];
386 }
387 } else
388#endif
389 instr = *(u32 *) pc;
390 } else if (thumb_mode(regs)) {
391 if (get_user(instr, (u16 __user *)pc))
392 goto die_sig;
393 if (is_wide_instruction(instr)) {
394 unsigned int instr2;
395 if (get_user(instr2, (u16 __user *)pc+1))
396 goto die_sig;
397 instr <<= 16;
398 instr |= instr2;
399 }
400 } else if (get_user(instr, (u32 __user *)pc)) {
401 goto die_sig;
402 }
403
404 if (call_undef_hook(regs, instr) == 0)
405 return;
406
407die_sig:
408#ifdef CONFIG_DEBUG_USER
409 if (user_debug & UDBG_UNDEFINED) {
410 printk(KERN_INFO "%s (%d): undefined instruction: pc=%p\n",
411 current->comm, task_pid_nr(current), pc);
412 dump_instr(KERN_INFO, regs);
413 }
414#endif
415
416 info.si_signo = SIGILL;
417 info.si_errno = 0;
418 info.si_code = ILL_ILLOPC;
419 info.si_addr = pc;
420
421 arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6);
422}
423
424asmlinkage void do_unexp_fiq (struct pt_regs *regs)
425{
426 printk("Hmm. Unexpected FIQ received, but trying to continue\n");
427 printk("You may have a hardware problem...\n");
428}
429
430/*
431 * bad_mode handles the impossible case in the vectors. If you see one of
432 * these, then it's extremely serious, and could mean you have buggy hardware.
433 * It never returns, and never tries to sync. We hope that we can at least
434 * dump out some state information...
435 */
436asmlinkage void bad_mode(struct pt_regs *regs, int reason)
437{
438 console_verbose();
439
440 printk(KERN_CRIT "Bad mode in %s handler detected\n", handler[reason]);
441
442 die("Oops - bad mode", regs, 0);
443 local_irq_disable();
444 panic("bad mode");
445}
446
447static int bad_syscall(int n, struct pt_regs *regs)
448{
449 struct thread_info *thread = current_thread_info();
450 siginfo_t info;
451
452 if ((current->personality & PER_MASK) != PER_LINUX &&
453 thread->exec_domain->handler) {
454 thread->exec_domain->handler(n, regs);
455 return regs->ARM_r0;
456 }
457
458#ifdef CONFIG_DEBUG_USER
459 if (user_debug & UDBG_SYSCALL) {
460 printk(KERN_ERR "[%d] %s: obsolete system call %08x.\n",
461 task_pid_nr(current), current->comm, n);
462 dump_instr(KERN_ERR, regs);
463 }
464#endif
465
466 info.si_signo = SIGILL;
467 info.si_errno = 0;
468 info.si_code = ILL_ILLTRP;
469 info.si_addr = (void __user *)instruction_pointer(regs) -
470 (thumb_mode(regs) ? 2 : 4);
471
472 arm_notify_die("Oops - bad syscall", regs, &info, n, 0);
473
474 return regs->ARM_r0;
475}
476
477static inline int
478do_cache_op(unsigned long start, unsigned long end, int flags)
479{
480 struct mm_struct *mm = current->active_mm;
481 struct vm_area_struct *vma;
482
483 if (end < start || flags)
484 return -EINVAL;
485
486 down_read(&mm->mmap_sem);
487 vma = find_vma(mm, start);
488 if (vma && vma->vm_start < end) {
489 if (start < vma->vm_start)
490 start = vma->vm_start;
491 if (end > vma->vm_end)
492 end = vma->vm_end;
493
494 up_read(&mm->mmap_sem);
495 return flush_cache_user_range(start, end);
496 }
497 up_read(&mm->mmap_sem);
498 return -EINVAL;
499}
500
501/*
502 * Handle all unrecognised system calls.
503 * 0x9f0000 - 0x9fffff are some more esoteric system calls
504 */
505#define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
506asmlinkage int arm_syscall(int no, struct pt_regs *regs)
507{
508 struct thread_info *thread = current_thread_info();
509 siginfo_t info;
510
511 if ((no >> 16) != (__ARM_NR_BASE>> 16))
512 return bad_syscall(no, regs);
513
514 switch (no & 0xffff) {
515 case 0: /* branch through 0 */
516 info.si_signo = SIGSEGV;
517 info.si_errno = 0;
518 info.si_code = SEGV_MAPERR;
519 info.si_addr = NULL;
520
521 arm_notify_die("branch through zero", regs, &info, 0, 0);
522 return 0;
523
524 case NR(breakpoint): /* SWI BREAK_POINT */
525 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
526 ptrace_break(current, regs);
527 return regs->ARM_r0;
528
529 /*
530 * Flush a region from virtual address 'r0' to virtual address 'r1'
531 * _exclusive_. There is no alignment requirement on either address;
532 * user space does not need to know the hardware cache layout.
533 *
534 * r2 contains flags. It should ALWAYS be passed as ZERO until it
535 * is defined to be something else. For now we ignore it, but may
536 * the fires of hell burn in your belly if you break this rule. ;)
537 *
538 * (at a later date, we may want to allow this call to not flush
539 * various aspects of the cache. Passing '0' will guarantee that
540 * everything necessary gets flushed to maintain consistency in
541 * the specified region).
542 */
543 case NR(cacheflush):
544 return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
545
546 case NR(usr26):
547 if (!(elf_hwcap & HWCAP_26BIT))
548 break;
549 regs->ARM_cpsr &= ~MODE32_BIT;
550 return regs->ARM_r0;
551
552 case NR(usr32):
553 if (!(elf_hwcap & HWCAP_26BIT))
554 break;
555 regs->ARM_cpsr |= MODE32_BIT;
556 return regs->ARM_r0;
557
558 case NR(set_tls):
559 thread->tp_value = regs->ARM_r0;
560 if (tls_emu)
561 return 0;
562 if (has_tls_reg) {
563 asm ("mcr p15, 0, %0, c13, c0, 3"
564 : : "r" (regs->ARM_r0));
565 } else {
566 /*
567 * User space must never try to access this directly.
568 * Expect your app to break eventually if you do so.
569 * The user helper at 0xffff0fe0 must be used instead.
570 * (see entry-armv.S for details)
571 */
572 *((unsigned int *)0xffff0ff0) = regs->ARM_r0;
573 }
574 return 0;
575
576#ifdef CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG
577 /*
578 * Atomically store r1 in *r2 if *r2 is equal to r0 for user space.
579 * Return zero in r0 if *MEM was changed or non-zero if no exchange
580 * happened. Also set the user C flag accordingly.
581 * If access permissions have to be fixed up then non-zero is
582 * returned and the operation has to be re-attempted.
583 *
584 * *NOTE*: This is a ghost syscall private to the kernel. Only the
585 * __kuser_cmpxchg code in entry-armv.S should be aware of its
586 * existence. Don't ever use this from user code.
587 */
588 case NR(cmpxchg):
589 for (;;) {
590 extern void do_DataAbort(unsigned long addr, unsigned int fsr,
591 struct pt_regs *regs);
592 unsigned long val;
593 unsigned long addr = regs->ARM_r2;
594 struct mm_struct *mm = current->mm;
595 pgd_t *pgd; pmd_t *pmd; pte_t *pte;
596 spinlock_t *ptl;
597
598 regs->ARM_cpsr &= ~PSR_C_BIT;
599 down_read(&mm->mmap_sem);
600 pgd = pgd_offset(mm, addr);
601 if (!pgd_present(*pgd))
602 goto bad_access;
603 pmd = pmd_offset(pgd, addr);
604 if (!pmd_present(*pmd))
605 goto bad_access;
606 pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
607 if (!pte_present(*pte) || !pte_write(*pte) || !pte_dirty(*pte)) {
608 pte_unmap_unlock(pte, ptl);
609 goto bad_access;
610 }
611 val = *(unsigned long *)addr;
612 val -= regs->ARM_r0;
613 if (val == 0) {
614 *(unsigned long *)addr = regs->ARM_r1;
615 regs->ARM_cpsr |= PSR_C_BIT;
616 }
617 pte_unmap_unlock(pte, ptl);
618 up_read(&mm->mmap_sem);
619 return val;
620
621 bad_access:
622 up_read(&mm->mmap_sem);
623 /* simulate a write access fault */
624 do_DataAbort(addr, 15 + (1 << 11), regs);
625 }
626#endif
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 printk("[%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(regs->ARM_fp, 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;
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
700void __bad_xchg(volatile void *ptr, int size)
701{
702 printk("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n",
703 __builtin_return_address(0), ptr, size);
704 BUG();
705}
706EXPORT_SYMBOL(__bad_xchg);
707
708/*
709 * A data abort trap was taken, but we did not handle the instruction.
710 * Try to abort the user program, or panic if it was the kernel.
711 */
712asmlinkage void
713baddataabort(int code, unsigned long instr, struct pt_regs *regs)
714{
715 unsigned long addr = instruction_pointer(regs);
716 siginfo_t info;
717
718#ifdef CONFIG_DEBUG_USER
719 if (user_debug & UDBG_BADABORT) {
720 printk(KERN_ERR "[%d] %s: bad data abort: code %d instr 0x%08lx\n",
721 task_pid_nr(current), current->comm, code, instr);
722 dump_instr(KERN_ERR, regs);
723 show_pte(current->mm, addr);
724 }
725#endif
726
727 info.si_signo = SIGILL;
728 info.si_errno = 0;
729 info.si_code = ILL_ILLOPC;
730 info.si_addr = (void __user *)addr;
731
732 arm_notify_die("unknown data abort code", regs, &info, instr, 0);
733}
734
735void __readwrite_bug(const char *fn)
736{
737 printk("%s called, but not implemented\n", fn);
738 BUG();
739}
740EXPORT_SYMBOL(__readwrite_bug);
741
742void __pte_error(const char *file, int line, pte_t pte)
743{
744 printk("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte));
745}
746
747void __pmd_error(const char *file, int line, pmd_t pmd)
748{
749 printk("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd));
750}
751
752void __pgd_error(const char *file, int line, pgd_t pgd)
753{
754 printk("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd));
755}
756
757asmlinkage void __div0(void)
758{
759 printk("Division by zero in kernel.\n");
760 dump_stack();
761}
762EXPORT_SYMBOL(__div0);
763
764void abort(void)
765{
766 BUG();
767
768 /* if that doesn't kill us, halt */
769 panic("Oops failed to kill thread");
770}
771EXPORT_SYMBOL(abort);
772
773void __init trap_init(void)
774{
775 return;
776}
777
778static void __init kuser_get_tls_init(unsigned long vectors)
779{
780 /*
781 * vectors + 0xfe0 = __kuser_get_tls
782 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8
783 */
784 if (tls_emu || has_tls_reg)
785 memcpy((void *)vectors + 0xfe0, (void *)vectors + 0xfe8, 4);
786}
787
788void __init early_trap_init(void *vectors_base)
789{
790 unsigned long vectors = (unsigned long)vectors_base;
791 extern char __stubs_start[], __stubs_end[];
792 extern char __vectors_start[], __vectors_end[];
793 extern char __kuser_helper_start[], __kuser_helper_end[];
794 int kuser_sz = __kuser_helper_end - __kuser_helper_start;
795
796 vectors_page = vectors_base;
797
798 /*
799 * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
800 * into the vector page, mapped at 0xffff0000, and ensure these
801 * are visible to the instruction stream.
802 */
803 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
804 memcpy((void *)vectors + 0x200, __stubs_start, __stubs_end - __stubs_start);
805 memcpy((void *)vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
806
807 /*
808 * Do processor specific fixups for the kuser helpers
809 */
810 kuser_get_tls_init(vectors);
811
812 /*
813 * Copy signal return handlers into the vector page, and
814 * set sigreturn to be a pointer to these.
815 */
816 memcpy((void *)(vectors + KERN_SIGRETURN_CODE - CONFIG_VECTORS_BASE),
817 sigreturn_codes, sizeof(sigreturn_codes));
818 memcpy((void *)(vectors + KERN_RESTART_CODE - CONFIG_VECTORS_BASE),
819 syscall_restart_code, sizeof(syscall_restart_code));
820
821 flush_icache_range(vectors, vectors + PAGE_SIZE);
822 modify_domain(DOMAIN_USER, DOMAIN_CLIENT);
823}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/arch/arm/kernel/traps.c
4 *
5 * Copyright (C) 1995-2009 Russell King
6 * Fragments that appear the same as linux/arch/i386/kernel/traps.c (C) Linus Torvalds
7 *
8 * 'traps.c' handles hardware exceptions after we have saved some state in
9 * 'linux/arch/arm/lib/traps.S'. Mostly a debugging aid, but will probably
10 * kill the offending process.
11 */
12#include <linux/signal.h>
13#include <linux/personality.h>
14#include <linux/kallsyms.h>
15#include <linux/spinlock.h>
16#include <linux/uaccess.h>
17#include <linux/hardirq.h>
18#include <linux/kdebug.h>
19#include <linux/kprobes.h>
20#include <linux/module.h>
21#include <linux/kexec.h>
22#include <linux/bug.h>
23#include <linux/delay.h>
24#include <linux/init.h>
25#include <linux/sched/signal.h>
26#include <linux/sched/debug.h>
27#include <linux/sched/task_stack.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,
66 unsigned long frame, const char *loglvl)
67{
68 unsigned long end = frame + 4 + sizeof(struct pt_regs);
69
70#ifdef CONFIG_KALLSYMS
71 printk("%s[<%08lx>] (%ps) from [<%08lx>] (%pS)\n",
72 loglvl, where, (void *)where, from, (void *)from);
73#else
74 printk("%sFunction entered at [<%08lx>] from [<%08lx>]\n",
75 loglvl, where, from);
76#endif
77
78 if (in_entry_text(from) && end <= ALIGN(frame, THREAD_SIZE))
79 dump_mem(loglvl, "Exception stack", frame + 4, end);
80}
81
82void dump_backtrace_stm(u32 *stack, u32 instruction, const char *loglvl)
83{
84 char str[80], *p;
85 unsigned int x;
86 int reg;
87
88 for (reg = 10, x = 0, p = str; reg >= 0; reg--) {
89 if (instruction & BIT(reg)) {
90 p += sprintf(p, " r%d:%08x", reg, *stack--);
91 if (++x == 6) {
92 x = 0;
93 p = str;
94 printk("%s%s\n", loglvl, str);
95 }
96 }
97 }
98 if (p != str)
99 printk("%s%s\n", loglvl, str);
100}
101
102#ifndef CONFIG_ARM_UNWIND
103/*
104 * Stack pointers should always be within the kernels view of
105 * physical memory. If it is not there, then we can't dump
106 * out any information relating to the stack.
107 */
108static int verify_stack(unsigned long sp)
109{
110 if (sp < PAGE_OFFSET ||
111 (sp > (unsigned long)high_memory && high_memory != NULL))
112 return -EFAULT;
113
114 return 0;
115}
116#endif
117
118/*
119 * Dump out the contents of some memory nicely...
120 */
121static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
122 unsigned long top)
123{
124 unsigned long first;
125 mm_segment_t fs;
126 int i;
127
128 /*
129 * We need to switch to kernel mode so that we can use __get_user
130 * to safely read from kernel space. Note that we now dump the
131 * code first, just in case the backtrace kills us.
132 */
133 fs = get_fs();
134 set_fs(KERNEL_DS);
135
136 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top);
137
138 for (first = bottom & ~31; first < top; first += 32) {
139 unsigned long p;
140 char str[sizeof(" 12345678") * 8 + 1];
141
142 memset(str, ' ', sizeof(str));
143 str[sizeof(str) - 1] = '\0';
144
145 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
146 if (p >= bottom && p < top) {
147 unsigned long val;
148 if (__get_user(val, (unsigned long *)p) == 0)
149 sprintf(str + i * 9, " %08lx", val);
150 else
151 sprintf(str + i * 9, " ????????");
152 }
153 }
154 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
155 }
156
157 set_fs(fs);
158}
159
160static void __dump_instr(const char *lvl, struct pt_regs *regs)
161{
162 unsigned long addr = instruction_pointer(regs);
163 const int thumb = thumb_mode(regs);
164 const int width = thumb ? 4 : 8;
165 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
166 int i;
167
168 /*
169 * Note that we now dump the code first, just in case the backtrace
170 * kills us.
171 */
172
173 for (i = -4; i < 1 + !!thumb; i++) {
174 unsigned int val, bad;
175
176 if (thumb)
177 bad = get_user(val, &((u16 *)addr)[i]);
178 else
179 bad = get_user(val, &((u32 *)addr)[i]);
180
181 if (!bad)
182 p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ",
183 width, val);
184 else {
185 p += sprintf(p, "bad PC value");
186 break;
187 }
188 }
189 printk("%sCode: %s\n", lvl, str);
190}
191
192static void dump_instr(const char *lvl, struct pt_regs *regs)
193{
194 mm_segment_t fs;
195
196 if (!user_mode(regs)) {
197 fs = get_fs();
198 set_fs(KERNEL_DS);
199 __dump_instr(lvl, regs);
200 set_fs(fs);
201 } else {
202 __dump_instr(lvl, regs);
203 }
204}
205
206#ifdef CONFIG_ARM_UNWIND
207static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
208 const char *loglvl)
209{
210 unwind_backtrace(regs, tsk, loglvl);
211}
212#else
213static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
214 const char *loglvl)
215{
216 unsigned int fp, mode;
217 int ok = 1;
218
219 printk("%sBacktrace: ", loglvl);
220
221 if (!tsk)
222 tsk = current;
223
224 if (regs) {
225 fp = frame_pointer(regs);
226 mode = processor_mode(regs);
227 } else if (tsk != current) {
228 fp = thread_saved_fp(tsk);
229 mode = 0x10;
230 } else {
231 asm("mov %0, fp" : "=r" (fp) : : "cc");
232 mode = 0x10;
233 }
234
235 if (!fp) {
236 pr_cont("no frame pointer");
237 ok = 0;
238 } else if (verify_stack(fp)) {
239 pr_cont("invalid frame pointer 0x%08x", fp);
240 ok = 0;
241 } else if (fp < (unsigned long)end_of_stack(tsk))
242 pr_cont("frame pointer underflow");
243 pr_cont("\n");
244
245 if (ok)
246 c_backtrace(fp, mode, loglvl);
247}
248#endif
249
250void show_stack(struct task_struct *tsk, unsigned long *sp, const char *loglvl)
251{
252 dump_backtrace(NULL, tsk, loglvl);
253 barrier();
254}
255
256#ifdef CONFIG_PREEMPT
257#define S_PREEMPT " PREEMPT"
258#elif defined(CONFIG_PREEMPT_RT)
259#define S_PREEMPT " PREEMPT_RT"
260#else
261#define S_PREEMPT ""
262#endif
263#ifdef CONFIG_SMP
264#define S_SMP " SMP"
265#else
266#define S_SMP ""
267#endif
268#ifdef CONFIG_THUMB2_KERNEL
269#define S_ISA " THUMB2"
270#else
271#define S_ISA " ARM"
272#endif
273
274static int __die(const char *str, int err, struct pt_regs *regs)
275{
276 struct task_struct *tsk = current;
277 static int die_counter;
278 int ret;
279
280 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP S_ISA "\n",
281 str, err, ++die_counter);
282
283 /* trap and error numbers are mostly meaningless on ARM */
284 ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV);
285 if (ret == NOTIFY_STOP)
286 return 1;
287
288 print_modules();
289 __show_regs(regs);
290 __show_regs_alloc_free(regs);
291 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
292 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk));
293
294 if (!user_mode(regs) || in_interrupt()) {
295 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp,
296 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
297 dump_backtrace(regs, tsk, KERN_EMERG);
298 dump_instr(KERN_EMERG, regs);
299 }
300
301 return 0;
302}
303
304static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
305static int die_owner = -1;
306static unsigned int die_nest_count;
307
308static unsigned long oops_begin(void)
309{
310 int cpu;
311 unsigned long flags;
312
313 oops_enter();
314
315 /* racy, but better than risking deadlock. */
316 raw_local_irq_save(flags);
317 cpu = smp_processor_id();
318 if (!arch_spin_trylock(&die_lock)) {
319 if (cpu == die_owner)
320 /* nested oops. should stop eventually */;
321 else
322 arch_spin_lock(&die_lock);
323 }
324 die_nest_count++;
325 die_owner = cpu;
326 console_verbose();
327 bust_spinlocks(1);
328 return flags;
329}
330
331static void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
332{
333 if (regs && kexec_should_crash(current))
334 crash_kexec(regs);
335
336 bust_spinlocks(0);
337 die_owner = -1;
338 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
339 die_nest_count--;
340 if (!die_nest_count)
341 /* Nest count reaches zero, release the lock. */
342 arch_spin_unlock(&die_lock);
343 raw_local_irq_restore(flags);
344 oops_exit();
345
346 if (in_interrupt())
347 panic("Fatal exception in interrupt");
348 if (panic_on_oops)
349 panic("Fatal exception");
350 if (signr)
351 do_exit(signr);
352}
353
354/*
355 * This function is protected against re-entrancy.
356 */
357void die(const char *str, struct pt_regs *regs, int err)
358{
359 enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE;
360 unsigned long flags = oops_begin();
361 int sig = SIGSEGV;
362
363 if (!user_mode(regs))
364 bug_type = report_bug(regs->ARM_pc, regs);
365 if (bug_type != BUG_TRAP_TYPE_NONE)
366 str = "Oops - BUG";
367
368 if (__die(str, err, regs))
369 sig = 0;
370
371 oops_end(flags, regs, sig);
372}
373
374void arm_notify_die(const char *str, struct pt_regs *regs,
375 int signo, int si_code, void __user *addr,
376 unsigned long err, unsigned long trap)
377{
378 if (user_mode(regs)) {
379 current->thread.error_code = err;
380 current->thread.trap_no = trap;
381
382 force_sig_fault(signo, si_code, addr);
383 } else {
384 die(str, regs, err);
385 }
386}
387
388#ifdef CONFIG_GENERIC_BUG
389
390int is_valid_bugaddr(unsigned long pc)
391{
392#ifdef CONFIG_THUMB2_KERNEL
393 u16 bkpt;
394 u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE);
395#else
396 u32 bkpt;
397 u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE);
398#endif
399
400 if (get_kernel_nofault(bkpt, (void *)pc))
401 return 0;
402
403 return bkpt == insn;
404}
405
406#endif
407
408static LIST_HEAD(undef_hook);
409static DEFINE_RAW_SPINLOCK(undef_lock);
410
411void register_undef_hook(struct undef_hook *hook)
412{
413 unsigned long flags;
414
415 raw_spin_lock_irqsave(&undef_lock, flags);
416 list_add(&hook->node, &undef_hook);
417 raw_spin_unlock_irqrestore(&undef_lock, flags);
418}
419
420void unregister_undef_hook(struct undef_hook *hook)
421{
422 unsigned long flags;
423
424 raw_spin_lock_irqsave(&undef_lock, flags);
425 list_del(&hook->node);
426 raw_spin_unlock_irqrestore(&undef_lock, flags);
427}
428
429static nokprobe_inline
430int call_undef_hook(struct pt_regs *regs, unsigned int instr)
431{
432 struct undef_hook *hook;
433 unsigned long flags;
434 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL;
435
436 raw_spin_lock_irqsave(&undef_lock, flags);
437 list_for_each_entry(hook, &undef_hook, node)
438 if ((instr & hook->instr_mask) == hook->instr_val &&
439 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val)
440 fn = hook->fn;
441 raw_spin_unlock_irqrestore(&undef_lock, flags);
442
443 return fn ? fn(regs, instr) : 1;
444}
445
446asmlinkage void do_undefinstr(struct pt_regs *regs)
447{
448 unsigned int instr;
449 void __user *pc;
450
451 pc = (void __user *)instruction_pointer(regs);
452
453 if (processor_mode(regs) == SVC_MODE) {
454#ifdef CONFIG_THUMB2_KERNEL
455 if (thumb_mode(regs)) {
456 instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]);
457 if (is_wide_instruction(instr)) {
458 u16 inst2;
459 inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]);
460 instr = __opcode_thumb32_compose(instr, inst2);
461 }
462 } else
463#endif
464 instr = __mem_to_opcode_arm(*(u32 *) pc);
465 } else if (thumb_mode(regs)) {
466 if (get_user(instr, (u16 __user *)pc))
467 goto die_sig;
468 instr = __mem_to_opcode_thumb16(instr);
469 if (is_wide_instruction(instr)) {
470 unsigned int instr2;
471 if (get_user(instr2, (u16 __user *)pc+1))
472 goto die_sig;
473 instr2 = __mem_to_opcode_thumb16(instr2);
474 instr = __opcode_thumb32_compose(instr, instr2);
475 }
476 } else {
477 if (get_user(instr, (u32 __user *)pc))
478 goto die_sig;
479 instr = __mem_to_opcode_arm(instr);
480 }
481
482 if (call_undef_hook(regs, instr) == 0)
483 return;
484
485die_sig:
486#ifdef CONFIG_DEBUG_USER
487 if (user_debug & UDBG_UNDEFINED) {
488 pr_info("%s (%d): undefined instruction: pc=%p\n",
489 current->comm, task_pid_nr(current), pc);
490 __show_regs(regs);
491 dump_instr(KERN_INFO, regs);
492 }
493#endif
494 arm_notify_die("Oops - undefined instruction", regs,
495 SIGILL, ILL_ILLOPC, pc, 0, 6);
496}
497NOKPROBE_SYMBOL(do_undefinstr)
498
499/*
500 * Handle FIQ similarly to NMI on x86 systems.
501 *
502 * The runtime environment for NMIs is extremely restrictive
503 * (NMIs can pre-empt critical sections meaning almost all locking is
504 * forbidden) meaning this default FIQ handling must only be used in
505 * circumstances where non-maskability improves robustness, such as
506 * watchdog or debug logic.
507 *
508 * This handler is not appropriate for general purpose use in drivers
509 * platform code and can be overrideen using set_fiq_handler.
510 */
511asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs)
512{
513 struct pt_regs *old_regs = set_irq_regs(regs);
514
515 nmi_enter();
516
517 /* nop. FIQ handlers for special arch/arm features can be added here. */
518
519 nmi_exit();
520
521 set_irq_regs(old_regs);
522}
523
524/*
525 * bad_mode handles the impossible case in the vectors. If you see one of
526 * these, then it's extremely serious, and could mean you have buggy hardware.
527 * It never returns, and never tries to sync. We hope that we can at least
528 * dump out some state information...
529 */
530asmlinkage void bad_mode(struct pt_regs *regs, int reason)
531{
532 console_verbose();
533
534 pr_crit("Bad mode in %s handler detected\n", handler[reason]);
535
536 die("Oops - bad mode", regs, 0);
537 local_irq_disable();
538 panic("bad mode");
539}
540
541static int bad_syscall(int n, struct pt_regs *regs)
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 arm_notify_die("Oops - bad syscall", regs, SIGILL, ILL_ILLTRP,
557 (void __user *)instruction_pointer(regs) -
558 (thumb_mode(regs) ? 2 : 4),
559 n, 0);
560
561 return regs->ARM_r0;
562}
563
564static inline int
565__do_cache_op(unsigned long start, unsigned long end)
566{
567 int ret;
568
569 do {
570 unsigned long chunk = min(PAGE_SIZE, end - start);
571
572 if (fatal_signal_pending(current))
573 return 0;
574
575 ret = flush_icache_user_range(start, start + chunk);
576 if (ret)
577 return ret;
578
579 cond_resched();
580 start += chunk;
581 } while (start < end);
582
583 return 0;
584}
585
586static inline int
587do_cache_op(unsigned long start, unsigned long end, int flags)
588{
589 if (end < start || flags)
590 return -EINVAL;
591
592 if (!access_ok(start, end - start))
593 return -EFAULT;
594
595 return __do_cache_op(start, end);
596}
597
598/*
599 * Handle all unrecognised system calls.
600 * 0x9f0000 - 0x9fffff are some more esoteric system calls
601 */
602#define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
603asmlinkage int arm_syscall(int no, struct pt_regs *regs)
604{
605 if ((no >> 16) != (__ARM_NR_BASE>> 16))
606 return bad_syscall(no, regs);
607
608 switch (no & 0xffff) {
609 case 0: /* branch through 0 */
610 arm_notify_die("branch through zero", regs,
611 SIGSEGV, SEGV_MAPERR, NULL, 0, 0);
612 return 0;
613
614 case NR(breakpoint): /* SWI BREAK_POINT */
615 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
616 ptrace_break(regs);
617 return regs->ARM_r0;
618
619 /*
620 * Flush a region from virtual address 'r0' to virtual address 'r1'
621 * _exclusive_. There is no alignment requirement on either address;
622 * user space does not need to know the hardware cache layout.
623 *
624 * r2 contains flags. It should ALWAYS be passed as ZERO until it
625 * is defined to be something else. For now we ignore it, but may
626 * the fires of hell burn in your belly if you break this rule. ;)
627 *
628 * (at a later date, we may want to allow this call to not flush
629 * various aspects of the cache. Passing '0' will guarantee that
630 * everything necessary gets flushed to maintain consistency in
631 * the specified region).
632 */
633 case NR(cacheflush):
634 return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
635
636 case NR(usr26):
637 if (!(elf_hwcap & HWCAP_26BIT))
638 break;
639 regs->ARM_cpsr &= ~MODE32_BIT;
640 return regs->ARM_r0;
641
642 case NR(usr32):
643 if (!(elf_hwcap & HWCAP_26BIT))
644 break;
645 regs->ARM_cpsr |= MODE32_BIT;
646 return regs->ARM_r0;
647
648 case NR(set_tls):
649 set_tls(regs->ARM_r0);
650 return 0;
651
652 case NR(get_tls):
653 return current_thread_info()->tp_value[0];
654
655 default:
656 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS
657 if not implemented, rather than raising SIGILL. This
658 way the calling program can gracefully determine whether
659 a feature is supported. */
660 if ((no & 0xffff) <= 0x7ff)
661 return -ENOSYS;
662 break;
663 }
664#ifdef CONFIG_DEBUG_USER
665 /*
666 * experience shows that these seem to indicate that
667 * something catastrophic has happened
668 */
669 if (user_debug & UDBG_SYSCALL) {
670 pr_err("[%d] %s: arm syscall %d\n",
671 task_pid_nr(current), current->comm, no);
672 dump_instr(KERN_ERR, regs);
673 if (user_mode(regs)) {
674 __show_regs(regs);
675 c_backtrace(frame_pointer(regs), processor_mode(regs), KERN_ERR);
676 }
677 }
678#endif
679 arm_notify_die("Oops - bad syscall(2)", regs, SIGILL, ILL_ILLTRP,
680 (void __user *)instruction_pointer(regs) -
681 (thumb_mode(regs) ? 2 : 4),
682 no, 0);
683 return 0;
684}
685
686#ifdef CONFIG_TLS_REG_EMUL
687
688/*
689 * We might be running on an ARMv6+ processor which should have the TLS
690 * register but for some reason we can't use it, or maybe an SMP system
691 * using a pre-ARMv6 processor (there are apparently a few prototypes like
692 * that in existence) and therefore access to that register must be
693 * emulated.
694 */
695
696static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
697{
698 int reg = (instr >> 12) & 15;
699 if (reg == 15)
700 return 1;
701 regs->uregs[reg] = current_thread_info()->tp_value[0];
702 regs->ARM_pc += 4;
703 return 0;
704}
705
706static struct undef_hook arm_mrc_hook = {
707 .instr_mask = 0x0fff0fff,
708 .instr_val = 0x0e1d0f70,
709 .cpsr_mask = PSR_T_BIT,
710 .cpsr_val = 0,
711 .fn = get_tp_trap,
712};
713
714static int __init arm_mrc_hook_init(void)
715{
716 register_undef_hook(&arm_mrc_hook);
717 return 0;
718}
719
720late_initcall(arm_mrc_hook_init);
721
722#endif
723
724/*
725 * A data abort trap was taken, but we did not handle the instruction.
726 * Try to abort the user program, or panic if it was the kernel.
727 */
728asmlinkage void
729baddataabort(int code, unsigned long instr, struct pt_regs *regs)
730{
731 unsigned long addr = instruction_pointer(regs);
732
733#ifdef CONFIG_DEBUG_USER
734 if (user_debug & UDBG_BADABORT) {
735 pr_err("8<--- cut here ---\n");
736 pr_err("[%d] %s: bad data abort: code %d instr 0x%08lx\n",
737 task_pid_nr(current), current->comm, code, instr);
738 dump_instr(KERN_ERR, regs);
739 show_pte(KERN_ERR, current->mm, addr);
740 }
741#endif
742
743 arm_notify_die("unknown data abort code", regs,
744 SIGILL, ILL_ILLOPC, (void __user *)addr, instr, 0);
745}
746
747void __readwrite_bug(const char *fn)
748{
749 pr_err("%s called, but not implemented\n", fn);
750 BUG();
751}
752EXPORT_SYMBOL(__readwrite_bug);
753
754void __pte_error(const char *file, int line, pte_t pte)
755{
756 pr_err("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte));
757}
758
759void __pmd_error(const char *file, int line, pmd_t pmd)
760{
761 pr_err("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd));
762}
763
764void __pgd_error(const char *file, int line, pgd_t pgd)
765{
766 pr_err("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd));
767}
768
769asmlinkage void __div0(void)
770{
771 pr_err("Division by zero in kernel.\n");
772 dump_stack();
773}
774EXPORT_SYMBOL(__div0);
775
776void abort(void)
777{
778 BUG();
779
780 /* if that doesn't kill us, halt */
781 panic("Oops failed to kill thread");
782}
783
784void __init trap_init(void)
785{
786 return;
787}
788
789#ifdef CONFIG_KUSER_HELPERS
790static void __init kuser_init(void *vectors)
791{
792 extern char __kuser_helper_start[], __kuser_helper_end[];
793 int kuser_sz = __kuser_helper_end - __kuser_helper_start;
794
795 memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
796
797 /*
798 * vectors + 0xfe0 = __kuser_get_tls
799 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8
800 */
801 if (tls_emu || has_tls_reg)
802 memcpy(vectors + 0xfe0, vectors + 0xfe8, 4);
803}
804#else
805static inline void __init kuser_init(void *vectors)
806{
807}
808#endif
809
810void __init early_trap_init(void *vectors_base)
811{
812#ifndef CONFIG_CPU_V7M
813 unsigned long vectors = (unsigned long)vectors_base;
814 extern char __stubs_start[], __stubs_end[];
815 extern char __vectors_start[], __vectors_end[];
816 unsigned i;
817
818 vectors_page = vectors_base;
819
820 /*
821 * Poison the vectors page with an undefined instruction. This
822 * instruction is chosen to be undefined for both ARM and Thumb
823 * ISAs. The Thumb version is an undefined instruction with a
824 * branch back to the undefined instruction.
825 */
826 for (i = 0; i < PAGE_SIZE / sizeof(u32); i++)
827 ((u32 *)vectors_base)[i] = 0xe7fddef1;
828
829 /*
830 * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
831 * into the vector page, mapped at 0xffff0000, and ensure these
832 * are visible to the instruction stream.
833 */
834 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
835 memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start);
836
837 kuser_init(vectors_base);
838
839 flush_icache_range(vectors, vectors + PAGE_SIZE * 2);
840#else /* ifndef CONFIG_CPU_V7M */
841 /*
842 * on V7-M there is no need to copy the vector table to a dedicated
843 * memory area. The address is configurable and so a table in the kernel
844 * image can be used.
845 */
846#endif
847}