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
40 static const char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" };
41
42 void *vectors_page;
43
44 #ifdef CONFIG_DEBUG_USER
45 unsigned int user_debug;
46
user_debug_setup(char * str)47 static 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
55 static void dump_mem(const char *, const char *, unsigned long, unsigned long);
56
dump_backtrace_entry(unsigned long where,unsigned long from,unsigned long frame)57 void 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 */
verify_stack(unsigned long sp)75 static 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 */
dump_mem(const char * lvl,const char * str,unsigned long bottom,unsigned long top)88 static 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
dump_instr(const char * lvl,struct pt_regs * regs)127 static 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
dump_backtrace(struct pt_regs * regs,struct task_struct * tsk)166 static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
167 {
168 unwind_backtrace(regs, tsk);
169 }
170 #else
dump_backtrace(struct pt_regs * regs,struct task_struct * tsk)171 static 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
dump_stack(void)207 void dump_stack(void)
208 {
209 dump_backtrace(NULL, NULL);
210 }
211
212 EXPORT_SYMBOL(dump_stack);
213
show_stack(struct task_struct * tsk,unsigned long * sp)214 void 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
__die(const char * str,int err,struct thread_info * thread,struct pt_regs * regs)236 static 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
265 static DEFINE_RAW_SPINLOCK(die_lock);
266
267 /*
268 * This function is protected against re-entrancy.
269 */
die(const char * str,struct pt_regs * regs,int err)270 void 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
arm_notify_die(const char * str,struct pt_regs * regs,struct siginfo * info,unsigned long err,unsigned long trap)303 void 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
is_valid_bugaddr(unsigned long pc)318 int 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
334 static LIST_HEAD(undef_hook);
335 static DEFINE_RAW_SPINLOCK(undef_lock);
336
register_undef_hook(struct undef_hook * hook)337 void 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
unregister_undef_hook(struct undef_hook * hook)346 void 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
call_undef_hook(struct pt_regs * regs,unsigned int instr)355 static 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
do_undefinstr(struct pt_regs * regs)371 asmlinkage 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
407 die_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
do_unexp_fiq(struct pt_regs * regs)424 asmlinkage 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 */
bad_mode(struct pt_regs * regs,int reason)436 asmlinkage 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
bad_syscall(int n,struct pt_regs * regs)447 static 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
477 static inline void
do_cache_op(unsigned long start,unsigned long end,int flags)478 do_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;
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 flush_cache_user_range(start, end);
496 return;
497 }
498 up_read(&mm->mmap_sem);
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)
arm_syscall(int no,struct pt_regs * regs)506 asmlinkage int arm_syscall(int no, struct pt_regs *regs)
507 {
508 struct thread_info *thread = current_thread_info();
509 siginfo_t info;
510
511 /* Emulate/fallthrough. */
512 if (no == -1)
513 return regs->ARM_r0;
514
515 if ((no >> 16) != (__ARM_NR_BASE>> 16))
516 return bad_syscall(no, regs);
517
518 switch (no & 0xffff) {
519 case 0: /* branch through 0 */
520 info.si_signo = SIGSEGV;
521 info.si_errno = 0;
522 info.si_code = SEGV_MAPERR;
523 info.si_addr = NULL;
524
525 arm_notify_die("branch through zero", regs, &info, 0, 0);
526 return 0;
527
528 case NR(breakpoint): /* SWI BREAK_POINT */
529 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
530 ptrace_break(current, regs);
531 return regs->ARM_r0;
532
533 /*
534 * Flush a region from virtual address 'r0' to virtual address 'r1'
535 * _exclusive_. There is no alignment requirement on either address;
536 * user space does not need to know the hardware cache layout.
537 *
538 * r2 contains flags. It should ALWAYS be passed as ZERO until it
539 * is defined to be something else. For now we ignore it, but may
540 * the fires of hell burn in your belly if you break this rule. ;)
541 *
542 * (at a later date, we may want to allow this call to not flush
543 * various aspects of the cache. Passing '0' will guarantee that
544 * everything necessary gets flushed to maintain consistency in
545 * the specified region).
546 */
547 case NR(cacheflush):
548 do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
549 return 0;
550
551 case NR(usr26):
552 if (!(elf_hwcap & HWCAP_26BIT))
553 break;
554 regs->ARM_cpsr &= ~MODE32_BIT;
555 return regs->ARM_r0;
556
557 case NR(usr32):
558 if (!(elf_hwcap & HWCAP_26BIT))
559 break;
560 regs->ARM_cpsr |= MODE32_BIT;
561 return regs->ARM_r0;
562
563 case NR(set_tls):
564 thread->tp_value = regs->ARM_r0;
565 if (tls_emu)
566 return 0;
567 if (has_tls_reg) {
568 asm ("mcr p15, 0, %0, c13, c0, 3"
569 : : "r" (regs->ARM_r0));
570 } else {
571 /*
572 * User space must never try to access this directly.
573 * Expect your app to break eventually if you do so.
574 * The user helper at 0xffff0fe0 must be used instead.
575 * (see entry-armv.S for details)
576 */
577 *((unsigned int *)0xffff0ff0) = regs->ARM_r0;
578 }
579 return 0;
580
581 #ifdef CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG
582 /*
583 * Atomically store r1 in *r2 if *r2 is equal to r0 for user space.
584 * Return zero in r0 if *MEM was changed or non-zero if no exchange
585 * happened. Also set the user C flag accordingly.
586 * If access permissions have to be fixed up then non-zero is
587 * returned and the operation has to be re-attempted.
588 *
589 * *NOTE*: This is a ghost syscall private to the kernel. Only the
590 * __kuser_cmpxchg code in entry-armv.S should be aware of its
591 * existence. Don't ever use this from user code.
592 */
593 case NR(cmpxchg):
594 for (;;) {
595 extern void do_DataAbort(unsigned long addr, unsigned int fsr,
596 struct pt_regs *regs);
597 unsigned long val;
598 unsigned long addr = regs->ARM_r2;
599 struct mm_struct *mm = current->mm;
600 pgd_t *pgd; pmd_t *pmd; pte_t *pte;
601 spinlock_t *ptl;
602
603 regs->ARM_cpsr &= ~PSR_C_BIT;
604 down_read(&mm->mmap_sem);
605 pgd = pgd_offset(mm, addr);
606 if (!pgd_present(*pgd))
607 goto bad_access;
608 pmd = pmd_offset(pgd, addr);
609 if (!pmd_present(*pmd))
610 goto bad_access;
611 pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
612 if (!pte_present(*pte) || !pte_write(*pte) || !pte_dirty(*pte)) {
613 pte_unmap_unlock(pte, ptl);
614 goto bad_access;
615 }
616 val = *(unsigned long *)addr;
617 val -= regs->ARM_r0;
618 if (val == 0) {
619 *(unsigned long *)addr = regs->ARM_r1;
620 regs->ARM_cpsr |= PSR_C_BIT;
621 }
622 pte_unmap_unlock(pte, ptl);
623 up_read(&mm->mmap_sem);
624 return val;
625
626 bad_access:
627 up_read(&mm->mmap_sem);
628 /* simulate a write access fault */
629 do_DataAbort(addr, 15 + (1 << 11), regs);
630 }
631 #endif
632
633 default:
634 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS
635 if not implemented, rather than raising SIGILL. This
636 way the calling program can gracefully determine whether
637 a feature is supported. */
638 if ((no & 0xffff) <= 0x7ff)
639 return -ENOSYS;
640 break;
641 }
642 #ifdef CONFIG_DEBUG_USER
643 /*
644 * experience shows that these seem to indicate that
645 * something catastrophic has happened
646 */
647 if (user_debug & UDBG_SYSCALL) {
648 printk("[%d] %s: arm syscall %d\n",
649 task_pid_nr(current), current->comm, no);
650 dump_instr("", regs);
651 if (user_mode(regs)) {
652 __show_regs(regs);
653 c_backtrace(regs->ARM_fp, processor_mode(regs));
654 }
655 }
656 #endif
657 info.si_signo = SIGILL;
658 info.si_errno = 0;
659 info.si_code = ILL_ILLTRP;
660 info.si_addr = (void __user *)instruction_pointer(regs) -
661 (thumb_mode(regs) ? 2 : 4);
662
663 arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0);
664 return 0;
665 }
666
667 #ifdef CONFIG_TLS_REG_EMUL
668
669 /*
670 * We might be running on an ARMv6+ processor which should have the TLS
671 * register but for some reason we can't use it, or maybe an SMP system
672 * using a pre-ARMv6 processor (there are apparently a few prototypes like
673 * that in existence) and therefore access to that register must be
674 * emulated.
675 */
676
get_tp_trap(struct pt_regs * regs,unsigned int instr)677 static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
678 {
679 int reg = (instr >> 12) & 15;
680 if (reg == 15)
681 return 1;
682 regs->uregs[reg] = current_thread_info()->tp_value;
683 regs->ARM_pc += 4;
684 return 0;
685 }
686
687 static struct undef_hook arm_mrc_hook = {
688 .instr_mask = 0x0fff0fff,
689 .instr_val = 0x0e1d0f70,
690 .cpsr_mask = PSR_T_BIT,
691 .cpsr_val = 0,
692 .fn = get_tp_trap,
693 };
694
arm_mrc_hook_init(void)695 static int __init arm_mrc_hook_init(void)
696 {
697 register_undef_hook(&arm_mrc_hook);
698 return 0;
699 }
700
701 late_initcall(arm_mrc_hook_init);
702
703 #endif
704
__bad_xchg(volatile void * ptr,int size)705 void __bad_xchg(volatile void *ptr, int size)
706 {
707 printk("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n",
708 __builtin_return_address(0), ptr, size);
709 BUG();
710 }
711 EXPORT_SYMBOL(__bad_xchg);
712
713 /*
714 * A data abort trap was taken, but we did not handle the instruction.
715 * Try to abort the user program, or panic if it was the kernel.
716 */
717 asmlinkage void
baddataabort(int code,unsigned long instr,struct pt_regs * regs)718 baddataabort(int code, unsigned long instr, struct pt_regs *regs)
719 {
720 unsigned long addr = instruction_pointer(regs);
721 siginfo_t info;
722
723 #ifdef CONFIG_DEBUG_USER
724 if (user_debug & UDBG_BADABORT) {
725 printk(KERN_ERR "[%d] %s: bad data abort: code %d instr 0x%08lx\n",
726 task_pid_nr(current), current->comm, code, instr);
727 dump_instr(KERN_ERR, regs);
728 show_pte(current->mm, addr);
729 }
730 #endif
731
732 info.si_signo = SIGILL;
733 info.si_errno = 0;
734 info.si_code = ILL_ILLOPC;
735 info.si_addr = (void __user *)addr;
736
737 arm_notify_die("unknown data abort code", regs, &info, instr, 0);
738 }
739
__readwrite_bug(const char * fn)740 void __readwrite_bug(const char *fn)
741 {
742 printk("%s called, but not implemented\n", fn);
743 BUG();
744 }
745 EXPORT_SYMBOL(__readwrite_bug);
746
__pte_error(const char * file,int line,pte_t pte)747 void __pte_error(const char *file, int line, pte_t pte)
748 {
749 printk("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte));
750 }
751
__pmd_error(const char * file,int line,pmd_t pmd)752 void __pmd_error(const char *file, int line, pmd_t pmd)
753 {
754 printk("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd));
755 }
756
__pgd_error(const char * file,int line,pgd_t pgd)757 void __pgd_error(const char *file, int line, pgd_t pgd)
758 {
759 printk("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd));
760 }
761
__div0(void)762 asmlinkage void __div0(void)
763 {
764 printk("Division by zero in kernel.\n");
765 dump_stack();
766 }
767 EXPORT_SYMBOL(__div0);
768
abort(void)769 void abort(void)
770 {
771 BUG();
772
773 /* if that doesn't kill us, halt */
774 panic("Oops failed to kill thread");
775 }
776 EXPORT_SYMBOL(abort);
777
trap_init(void)778 void __init trap_init(void)
779 {
780 return;
781 }
782
783 #ifdef CONFIG_KUSER_HELPERS
kuser_init(void * vectors)784 static void __init kuser_init(void *vectors)
785 {
786 extern char __kuser_helper_start[], __kuser_helper_end[];
787 int kuser_sz = __kuser_helper_end - __kuser_helper_start;
788
789 memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
790
791 /*
792 * vectors + 0xfe0 = __kuser_get_tls
793 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8
794 */
795 if (tls_emu || has_tls_reg)
796 memcpy(vectors + 0xfe0, vectors + 0xfe8, 4);
797 }
798 #else
kuser_init(void * vectors)799 static void __init kuser_init(void *vectors)
800 {
801 }
802 #endif
803
early_trap_init(void * vectors_base)804 void __init early_trap_init(void *vectors_base)
805 {
806 unsigned long vectors = (unsigned long)vectors_base;
807 extern char __stubs_start[], __stubs_end[];
808 extern char __vectors_start[], __vectors_end[];
809 unsigned i;
810
811 vectors_page = vectors_base;
812
813 /*
814 * Poison the vectors page with an undefined instruction. This
815 * instruction is chosen to be undefined for both ARM and Thumb
816 * ISAs. The Thumb version is an undefined instruction with a
817 * branch back to the undefined instruction.
818 */
819 for (i = 0; i < PAGE_SIZE / sizeof(u32); i++)
820 ((u32 *)vectors_base)[i] = 0xe7fddef1;
821
822 /*
823 * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
824 * into the vector page, mapped at 0xffff0000, and ensure these
825 * are visible to the instruction stream.
826 */
827 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
828 memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start);
829
830 kuser_init(vectors_base);
831
832 /*
833 * Copy signal return handlers into the vector page, and
834 * set sigreturn to be a pointer to these.
835 */
836 memcpy((void *)(vectors + KERN_SIGRETURN_CODE - CONFIG_VECTORS_BASE),
837 sigreturn_codes, sizeof(sigreturn_codes));
838
839 flush_icache_range(vectors, vectors + PAGE_SIZE * 2);
840 modify_domain(DOMAIN_USER, DOMAIN_CLIENT);
841 }
842