1 /*
2 * linux/arch/arm/kernel/traps.c
3 *
4 * Copyright (C) 1995-2009 Russell King
5 * Fragments that appear the same as linux/arch/i386/kernel/traps.c (C) Linus Torvalds
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * 'traps.c' handles hardware exceptions after we have saved some state in
12 * 'linux/arch/arm/lib/traps.S'. Mostly a debugging aid, but will probably
13 * kill the offending process.
14 */
15 #include <linux/signal.h>
16 #include <linux/personality.h>
17 #include <linux/kallsyms.h>
18 #include <linux/spinlock.h>
19 #include <linux/uaccess.h>
20 #include <linux/hardirq.h>
21 #include <linux/kdebug.h>
22 #include <linux/kprobes.h>
23 #include <linux/module.h>
24 #include <linux/kexec.h>
25 #include <linux/bug.h>
26 #include <linux/delay.h>
27 #include <linux/init.h>
28 #include <linux/sched.h>
29 #include <linux/irq.h>
30
31 #include <linux/atomic.h>
32 #include <asm/cacheflush.h>
33 #include <asm/exception.h>
34 #include <asm/unistd.h>
35 #include <asm/traps.h>
36 #include <asm/ptrace.h>
37 #include <asm/unwind.h>
38 #include <asm/tls.h>
39 #include <asm/system_misc.h>
40 #include <asm/opcodes.h>
41
42
43 static const char *handler[]= {
44 "prefetch abort",
45 "data abort",
46 "address exception",
47 "interrupt",
48 "undefined instruction",
49 };
50
51 void *vectors_page;
52
53 #ifdef CONFIG_DEBUG_USER
54 unsigned int user_debug;
55
user_debug_setup(char * str)56 static int __init user_debug_setup(char *str)
57 {
58 get_option(&str, &user_debug);
59 return 1;
60 }
61 __setup("user_debug=", user_debug_setup);
62 #endif
63
64 static void dump_mem(const char *, const char *, unsigned long, unsigned long);
65
dump_backtrace_entry(unsigned long where,unsigned long from,unsigned long frame)66 void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame)
67 {
68 #ifdef CONFIG_KALLSYMS
69 printk("[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from);
70 #else
71 printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
72 #endif
73
74 if (in_exception_text(where))
75 dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs));
76 }
77
78 #ifndef CONFIG_ARM_UNWIND
79 /*
80 * Stack pointers should always be within the kernels view of
81 * physical memory. If it is not there, then we can't dump
82 * out any information relating to the stack.
83 */
verify_stack(unsigned long sp)84 static int verify_stack(unsigned long sp)
85 {
86 if (sp < PAGE_OFFSET ||
87 (sp > (unsigned long)high_memory && high_memory != NULL))
88 return -EFAULT;
89
90 return 0;
91 }
92 #endif
93
94 /*
95 * Dump out the contents of some memory nicely...
96 */
dump_mem(const char * lvl,const char * str,unsigned long bottom,unsigned long top)97 static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
98 unsigned long top)
99 {
100 unsigned long first;
101 mm_segment_t fs;
102 int i;
103
104 /*
105 * We need to switch to kernel mode so that we can use __get_user
106 * to safely read from kernel space. Note that we now dump the
107 * code first, just in case the backtrace kills us.
108 */
109 fs = get_fs();
110 set_fs(KERNEL_DS);
111
112 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top);
113
114 for (first = bottom & ~31; first < top; first += 32) {
115 unsigned long p;
116 char str[sizeof(" 12345678") * 8 + 1];
117
118 memset(str, ' ', sizeof(str));
119 str[sizeof(str) - 1] = '\0';
120
121 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
122 if (p >= bottom && p < top) {
123 unsigned long val;
124 if (__get_user(val, (unsigned long *)p) == 0)
125 sprintf(str + i * 9, " %08lx", val);
126 else
127 sprintf(str + i * 9, " ????????");
128 }
129 }
130 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
131 }
132
133 set_fs(fs);
134 }
135
__dump_instr(const char * lvl,struct pt_regs * regs)136 static void __dump_instr(const char *lvl, struct pt_regs *regs)
137 {
138 unsigned long addr = instruction_pointer(regs);
139 const int thumb = thumb_mode(regs);
140 const int width = thumb ? 4 : 8;
141 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
142 int i;
143
144 /*
145 * Note that we now dump the code first, just in case the backtrace
146 * kills us.
147 */
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
dump_instr(const char * lvl,struct pt_regs * regs)168 static void dump_instr(const char *lvl, struct pt_regs *regs)
169 {
170 mm_segment_t fs;
171
172 if (!user_mode(regs)) {
173 fs = get_fs();
174 set_fs(KERNEL_DS);
175 __dump_instr(lvl, regs);
176 set_fs(fs);
177 } else {
178 __dump_instr(lvl, regs);
179 }
180 }
181
182 #ifdef CONFIG_ARM_UNWIND
dump_backtrace(struct pt_regs * regs,struct task_struct * tsk)183 static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
184 {
185 unwind_backtrace(regs, tsk);
186 }
187 #else
dump_backtrace(struct pt_regs * regs,struct task_struct * tsk)188 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
189 {
190 unsigned int fp, mode;
191 int ok = 1;
192
193 printk("Backtrace: ");
194
195 if (!tsk)
196 tsk = current;
197
198 if (regs) {
199 fp = frame_pointer(regs);
200 mode = processor_mode(regs);
201 } else if (tsk != current) {
202 fp = thread_saved_fp(tsk);
203 mode = 0x10;
204 } else {
205 asm("mov %0, fp" : "=r" (fp) : : "cc");
206 mode = 0x10;
207 }
208
209 if (!fp) {
210 pr_cont("no frame pointer");
211 ok = 0;
212 } else if (verify_stack(fp)) {
213 pr_cont("invalid frame pointer 0x%08x", fp);
214 ok = 0;
215 } else if (fp < (unsigned long)end_of_stack(tsk))
216 pr_cont("frame pointer underflow");
217 pr_cont("\n");
218
219 if (ok)
220 c_backtrace(fp, mode);
221 }
222 #endif
223
show_stack(struct task_struct * tsk,unsigned long * sp)224 void show_stack(struct task_struct *tsk, unsigned long *sp)
225 {
226 dump_backtrace(NULL, tsk);
227 barrier();
228 }
229
230 #ifdef CONFIG_PREEMPT
231 #define S_PREEMPT " PREEMPT"
232 #else
233 #define S_PREEMPT ""
234 #endif
235 #ifdef CONFIG_SMP
236 #define S_SMP " SMP"
237 #else
238 #define S_SMP ""
239 #endif
240 #ifdef CONFIG_THUMB2_KERNEL
241 #define S_ISA " THUMB2"
242 #else
243 #define S_ISA " ARM"
244 #endif
245
__die(const char * str,int err,struct pt_regs * regs)246 static int __die(const char *str, int err, struct pt_regs *regs)
247 {
248 struct task_struct *tsk = current;
249 static int die_counter;
250 int ret;
251
252 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP S_ISA "\n",
253 str, err, ++die_counter);
254
255 /* trap and error numbers are mostly meaningless on ARM */
256 ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV);
257 if (ret == NOTIFY_STOP)
258 return 1;
259
260 print_modules();
261 __show_regs(regs);
262 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
263 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk));
264
265 if (!user_mode(regs) || in_interrupt()) {
266 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp,
267 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
268 dump_backtrace(regs, tsk);
269 dump_instr(KERN_EMERG, regs);
270 }
271
272 return 0;
273 }
274
275 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
276 static int die_owner = -1;
277 static unsigned int die_nest_count;
278
oops_begin(void)279 static unsigned long oops_begin(void)
280 {
281 int cpu;
282 unsigned long flags;
283
284 oops_enter();
285
286 /* racy, but better than risking deadlock. */
287 raw_local_irq_save(flags);
288 cpu = smp_processor_id();
289 if (!arch_spin_trylock(&die_lock)) {
290 if (cpu == die_owner)
291 /* nested oops. should stop eventually */;
292 else
293 arch_spin_lock(&die_lock);
294 }
295 die_nest_count++;
296 die_owner = cpu;
297 console_verbose();
298 bust_spinlocks(1);
299 return flags;
300 }
301
oops_end(unsigned long flags,struct pt_regs * regs,int signr)302 static void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
303 {
304 if (regs && kexec_should_crash(current))
305 crash_kexec(regs);
306
307 bust_spinlocks(0);
308 die_owner = -1;
309 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
310 die_nest_count--;
311 if (!die_nest_count)
312 /* Nest count reaches zero, release the lock. */
313 arch_spin_unlock(&die_lock);
314 raw_local_irq_restore(flags);
315 oops_exit();
316
317 if (in_interrupt())
318 panic("Fatal exception in interrupt");
319 if (panic_on_oops)
320 panic("Fatal exception");
321 if (signr)
322 do_exit(signr);
323 }
324
325 /*
326 * This function is protected against re-entrancy.
327 */
die(const char * str,struct pt_regs * regs,int err)328 void die(const char *str, struct pt_regs *regs, int err)
329 {
330 enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE;
331 unsigned long flags = oops_begin();
332 int sig = SIGSEGV;
333
334 if (!user_mode(regs))
335 bug_type = report_bug(regs->ARM_pc, regs);
336 if (bug_type != BUG_TRAP_TYPE_NONE)
337 str = "Oops - BUG";
338
339 if (__die(str, err, regs))
340 sig = 0;
341
342 oops_end(flags, regs, sig);
343 }
344
arm_notify_die(const char * str,struct pt_regs * regs,struct siginfo * info,unsigned long err,unsigned long trap)345 void arm_notify_die(const char *str, struct pt_regs *regs,
346 struct siginfo *info, unsigned long err, unsigned long trap)
347 {
348 if (user_mode(regs)) {
349 current->thread.error_code = err;
350 current->thread.trap_no = trap;
351
352 force_sig_info(info->si_signo, info, current);
353 } else {
354 die(str, regs, err);
355 }
356 }
357
358 #ifdef CONFIG_GENERIC_BUG
359
is_valid_bugaddr(unsigned long pc)360 int is_valid_bugaddr(unsigned long pc)
361 {
362 #ifdef CONFIG_THUMB2_KERNEL
363 u16 bkpt;
364 u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE);
365 #else
366 u32 bkpt;
367 u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE);
368 #endif
369
370 if (probe_kernel_address((unsigned *)pc, bkpt))
371 return 0;
372
373 return bkpt == insn;
374 }
375
376 #endif
377
378 static LIST_HEAD(undef_hook);
379 static DEFINE_RAW_SPINLOCK(undef_lock);
380
register_undef_hook(struct undef_hook * hook)381 void register_undef_hook(struct undef_hook *hook)
382 {
383 unsigned long flags;
384
385 raw_spin_lock_irqsave(&undef_lock, flags);
386 list_add(&hook->node, &undef_hook);
387 raw_spin_unlock_irqrestore(&undef_lock, flags);
388 }
389
unregister_undef_hook(struct undef_hook * hook)390 void unregister_undef_hook(struct undef_hook *hook)
391 {
392 unsigned long flags;
393
394 raw_spin_lock_irqsave(&undef_lock, flags);
395 list_del(&hook->node);
396 raw_spin_unlock_irqrestore(&undef_lock, flags);
397 }
398
399 static nokprobe_inline
call_undef_hook(struct pt_regs * regs,unsigned int instr)400 int call_undef_hook(struct pt_regs *regs, unsigned int instr)
401 {
402 struct undef_hook *hook;
403 unsigned long flags;
404 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL;
405
406 raw_spin_lock_irqsave(&undef_lock, flags);
407 list_for_each_entry(hook, &undef_hook, node)
408 if ((instr & hook->instr_mask) == hook->instr_val &&
409 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val)
410 fn = hook->fn;
411 raw_spin_unlock_irqrestore(&undef_lock, flags);
412
413 return fn ? fn(regs, instr) : 1;
414 }
415
do_undefinstr(struct pt_regs * regs)416 asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
417 {
418 unsigned int instr;
419 siginfo_t info;
420 void __user *pc;
421
422 pc = (void __user *)instruction_pointer(regs);
423
424 if (processor_mode(regs) == SVC_MODE) {
425 #ifdef CONFIG_THUMB2_KERNEL
426 if (thumb_mode(regs)) {
427 instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]);
428 if (is_wide_instruction(instr)) {
429 u16 inst2;
430 inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]);
431 instr = __opcode_thumb32_compose(instr, inst2);
432 }
433 } else
434 #endif
435 instr = __mem_to_opcode_arm(*(u32 *) pc);
436 } else if (thumb_mode(regs)) {
437 if (get_user(instr, (u16 __user *)pc))
438 goto die_sig;
439 instr = __mem_to_opcode_thumb16(instr);
440 if (is_wide_instruction(instr)) {
441 unsigned int instr2;
442 if (get_user(instr2, (u16 __user *)pc+1))
443 goto die_sig;
444 instr2 = __mem_to_opcode_thumb16(instr2);
445 instr = __opcode_thumb32_compose(instr, instr2);
446 }
447 } else {
448 if (get_user(instr, (u32 __user *)pc))
449 goto die_sig;
450 instr = __mem_to_opcode_arm(instr);
451 }
452
453 if (call_undef_hook(regs, instr) == 0)
454 return;
455
456 die_sig:
457 #ifdef CONFIG_DEBUG_USER
458 if (user_debug & UDBG_UNDEFINED) {
459 pr_info("%s (%d): undefined instruction: pc=%p\n",
460 current->comm, task_pid_nr(current), pc);
461 __show_regs(regs);
462 dump_instr(KERN_INFO, regs);
463 }
464 #endif
465
466 info.si_signo = SIGILL;
467 info.si_errno = 0;
468 info.si_code = ILL_ILLOPC;
469 info.si_addr = pc;
470
471 arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6);
472 }
NOKPROBE_SYMBOL(do_undefinstr)473 NOKPROBE_SYMBOL(do_undefinstr)
474
475 /*
476 * Handle FIQ similarly to NMI on x86 systems.
477 *
478 * The runtime environment for NMIs is extremely restrictive
479 * (NMIs can pre-empt critical sections meaning almost all locking is
480 * forbidden) meaning this default FIQ handling must only be used in
481 * circumstances where non-maskability improves robustness, such as
482 * watchdog or debug logic.
483 *
484 * This handler is not appropriate for general purpose use in drivers
485 * platform code and can be overrideen using set_fiq_handler.
486 */
487 asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs)
488 {
489 struct pt_regs *old_regs = set_irq_regs(regs);
490
491 nmi_enter();
492
493 /* nop. FIQ handlers for special arch/arm features can be added here. */
494
495 nmi_exit();
496
497 set_irq_regs(old_regs);
498 }
499
500 /*
501 * bad_mode handles the impossible case in the vectors. If you see one of
502 * these, then it's extremely serious, and could mean you have buggy hardware.
503 * It never returns, and never tries to sync. We hope that we can at least
504 * dump out some state information...
505 */
bad_mode(struct pt_regs * regs,int reason)506 asmlinkage void bad_mode(struct pt_regs *regs, int reason)
507 {
508 console_verbose();
509
510 pr_crit("Bad mode in %s handler detected\n", handler[reason]);
511
512 die("Oops - bad mode", regs, 0);
513 local_irq_disable();
514 panic("bad mode");
515 }
516
bad_syscall(int n,struct pt_regs * regs)517 static int bad_syscall(int n, struct pt_regs *regs)
518 {
519 siginfo_t info;
520
521 if ((current->personality & PER_MASK) != PER_LINUX) {
522 send_sig(SIGSEGV, current, 1);
523 return regs->ARM_r0;
524 }
525
526 #ifdef CONFIG_DEBUG_USER
527 if (user_debug & UDBG_SYSCALL) {
528 pr_err("[%d] %s: obsolete system call %08x.\n",
529 task_pid_nr(current), current->comm, n);
530 dump_instr(KERN_ERR, regs);
531 }
532 #endif
533
534 info.si_signo = SIGILL;
535 info.si_errno = 0;
536 info.si_code = ILL_ILLTRP;
537 info.si_addr = (void __user *)instruction_pointer(regs) -
538 (thumb_mode(regs) ? 2 : 4);
539
540 arm_notify_die("Oops - bad syscall", regs, &info, n, 0);
541
542 return regs->ARM_r0;
543 }
544
545 static inline int
__do_cache_op(unsigned long start,unsigned long end)546 __do_cache_op(unsigned long start, unsigned long end)
547 {
548 int ret;
549
550 do {
551 unsigned long chunk = min(PAGE_SIZE, end - start);
552
553 if (fatal_signal_pending(current))
554 return 0;
555
556 ret = flush_cache_user_range(start, start + chunk);
557 if (ret)
558 return ret;
559
560 cond_resched();
561 start += chunk;
562 } while (start < end);
563
564 return 0;
565 }
566
567 static inline int
do_cache_op(unsigned long start,unsigned long end,int flags)568 do_cache_op(unsigned long start, unsigned long end, int flags)
569 {
570 if (end < start || flags)
571 return -EINVAL;
572
573 if (!access_ok(VERIFY_READ, start, end - start))
574 return -EFAULT;
575
576 return __do_cache_op(start, end);
577 }
578
579 /*
580 * Handle all unrecognised system calls.
581 * 0x9f0000 - 0x9fffff are some more esoteric system calls
582 */
583 #define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
arm_syscall(int no,struct pt_regs * regs)584 asmlinkage int arm_syscall(int no, struct pt_regs *regs)
585 {
586 siginfo_t info;
587
588 if ((no >> 16) != (__ARM_NR_BASE>> 16))
589 return bad_syscall(no, regs);
590
591 switch (no & 0xffff) {
592 case 0: /* branch through 0 */
593 info.si_signo = SIGSEGV;
594 info.si_errno = 0;
595 info.si_code = SEGV_MAPERR;
596 info.si_addr = NULL;
597
598 arm_notify_die("branch through zero", regs, &info, 0, 0);
599 return 0;
600
601 case NR(breakpoint): /* SWI BREAK_POINT */
602 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
603 ptrace_break(current, regs);
604 return regs->ARM_r0;
605
606 /*
607 * Flush a region from virtual address 'r0' to virtual address 'r1'
608 * _exclusive_. There is no alignment requirement on either address;
609 * user space does not need to know the hardware cache layout.
610 *
611 * r2 contains flags. It should ALWAYS be passed as ZERO until it
612 * is defined to be something else. For now we ignore it, but may
613 * the fires of hell burn in your belly if you break this rule. ;)
614 *
615 * (at a later date, we may want to allow this call to not flush
616 * various aspects of the cache. Passing '0' will guarantee that
617 * everything necessary gets flushed to maintain consistency in
618 * the specified region).
619 */
620 case NR(cacheflush):
621 return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
622
623 case NR(usr26):
624 if (!(elf_hwcap & HWCAP_26BIT))
625 break;
626 regs->ARM_cpsr &= ~MODE32_BIT;
627 return regs->ARM_r0;
628
629 case NR(usr32):
630 if (!(elf_hwcap & HWCAP_26BIT))
631 break;
632 regs->ARM_cpsr |= MODE32_BIT;
633 return regs->ARM_r0;
634
635 case NR(set_tls):
636 set_tls(regs->ARM_r0);
637 return 0;
638
639 default:
640 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS
641 if not implemented, rather than raising SIGILL. This
642 way the calling program can gracefully determine whether
643 a feature is supported. */
644 if ((no & 0xffff) <= 0x7ff)
645 return -ENOSYS;
646 break;
647 }
648 #ifdef CONFIG_DEBUG_USER
649 /*
650 * experience shows that these seem to indicate that
651 * something catastrophic has happened
652 */
653 if (user_debug & UDBG_SYSCALL) {
654 pr_err("[%d] %s: arm syscall %d\n",
655 task_pid_nr(current), current->comm, no);
656 dump_instr("", regs);
657 if (user_mode(regs)) {
658 __show_regs(regs);
659 c_backtrace(frame_pointer(regs), processor_mode(regs));
660 }
661 }
662 #endif
663 info.si_signo = SIGILL;
664 info.si_errno = 0;
665 info.si_code = ILL_ILLTRP;
666 info.si_addr = (void __user *)instruction_pointer(regs) -
667 (thumb_mode(regs) ? 2 : 4);
668
669 arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0);
670 return 0;
671 }
672
673 #ifdef CONFIG_TLS_REG_EMUL
674
675 /*
676 * We might be running on an ARMv6+ processor which should have the TLS
677 * register but for some reason we can't use it, or maybe an SMP system
678 * using a pre-ARMv6 processor (there are apparently a few prototypes like
679 * that in existence) and therefore access to that register must be
680 * emulated.
681 */
682
get_tp_trap(struct pt_regs * regs,unsigned int instr)683 static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
684 {
685 int reg = (instr >> 12) & 15;
686 if (reg == 15)
687 return 1;
688 regs->uregs[reg] = current_thread_info()->tp_value[0];
689 regs->ARM_pc += 4;
690 return 0;
691 }
692
693 static struct undef_hook arm_mrc_hook = {
694 .instr_mask = 0x0fff0fff,
695 .instr_val = 0x0e1d0f70,
696 .cpsr_mask = PSR_T_BIT,
697 .cpsr_val = 0,
698 .fn = get_tp_trap,
699 };
700
arm_mrc_hook_init(void)701 static int __init arm_mrc_hook_init(void)
702 {
703 register_undef_hook(&arm_mrc_hook);
704 return 0;
705 }
706
707 late_initcall(arm_mrc_hook_init);
708
709 #endif
710
711 /*
712 * A data abort trap was taken, but we did not handle the instruction.
713 * Try to abort the user program, or panic if it was the kernel.
714 */
715 asmlinkage void
baddataabort(int code,unsigned long instr,struct pt_regs * regs)716 baddataabort(int code, unsigned long instr, struct pt_regs *regs)
717 {
718 unsigned long addr = instruction_pointer(regs);
719 siginfo_t info;
720
721 #ifdef CONFIG_DEBUG_USER
722 if (user_debug & UDBG_BADABORT) {
723 pr_err("[%d] %s: bad data abort: code %d instr 0x%08lx\n",
724 task_pid_nr(current), current->comm, code, instr);
725 dump_instr(KERN_ERR, regs);
726 show_pte(current->mm, addr);
727 }
728 #endif
729
730 info.si_signo = SIGILL;
731 info.si_errno = 0;
732 info.si_code = ILL_ILLOPC;
733 info.si_addr = (void __user *)addr;
734
735 arm_notify_die("unknown data abort code", regs, &info, instr, 0);
736 }
737
__readwrite_bug(const char * fn)738 void __readwrite_bug(const char *fn)
739 {
740 pr_err("%s called, but not implemented\n", fn);
741 BUG();
742 }
743 EXPORT_SYMBOL(__readwrite_bug);
744
__pte_error(const char * file,int line,pte_t pte)745 void __pte_error(const char *file, int line, pte_t pte)
746 {
747 pr_err("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte));
748 }
749
__pmd_error(const char * file,int line,pmd_t pmd)750 void __pmd_error(const char *file, int line, pmd_t pmd)
751 {
752 pr_err("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd));
753 }
754
__pgd_error(const char * file,int line,pgd_t pgd)755 void __pgd_error(const char *file, int line, pgd_t pgd)
756 {
757 pr_err("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd));
758 }
759
__div0(void)760 asmlinkage void __div0(void)
761 {
762 pr_err("Division by zero in kernel.\n");
763 dump_stack();
764 }
765 EXPORT_SYMBOL(__div0);
766
abort(void)767 void abort(void)
768 {
769 BUG();
770
771 /* if that doesn't kill us, halt */
772 panic("Oops failed to kill thread");
773 }
774 EXPORT_SYMBOL(abort);
775
trap_init(void)776 void __init trap_init(void)
777 {
778 return;
779 }
780
781 #ifdef CONFIG_KUSER_HELPERS
kuser_init(void * vectors)782 static void __init kuser_init(void *vectors)
783 {
784 extern char __kuser_helper_start[], __kuser_helper_end[];
785 int kuser_sz = __kuser_helper_end - __kuser_helper_start;
786
787 memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
788
789 /*
790 * vectors + 0xfe0 = __kuser_get_tls
791 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8
792 */
793 if (tls_emu || has_tls_reg)
794 memcpy(vectors + 0xfe0, vectors + 0xfe8, 4);
795 }
796 #else
kuser_init(void * vectors)797 static inline void __init kuser_init(void *vectors)
798 {
799 }
800 #endif
801
early_trap_init(void * vectors_base)802 void __init early_trap_init(void *vectors_base)
803 {
804 #ifndef CONFIG_CPU_V7M
805 unsigned long vectors = (unsigned long)vectors_base;
806 extern char __stubs_start[], __stubs_end[];
807 extern char __vectors_start[], __vectors_end[];
808 unsigned i;
809
810 vectors_page = vectors_base;
811
812 /*
813 * Poison the vectors page with an undefined instruction. This
814 * instruction is chosen to be undefined for both ARM and Thumb
815 * ISAs. The Thumb version is an undefined instruction with a
816 * branch back to the undefined instruction.
817 */
818 for (i = 0; i < PAGE_SIZE / sizeof(u32); i++)
819 ((u32 *)vectors_base)[i] = 0xe7fddef1;
820
821 /*
822 * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
823 * into the vector page, mapped at 0xffff0000, and ensure these
824 * are visible to the instruction stream.
825 */
826 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
827 memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start);
828
829 kuser_init(vectors_base);
830
831 flush_icache_range(vectors, vectors + PAGE_SIZE * 2);
832 #else /* ifndef CONFIG_CPU_V7M */
833 /*
834 * on V7-M there is no need to copy the vector table to a dedicated
835 * memory area. The address is configurable and so a table in the kernel
836 * image can be used.
837 */
838 #endif
839 }
840