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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#include <linux/irq.h>
29
30#include <linux/atomic.h>
31#include <asm/cacheflush.h>
32#include <asm/exception.h>
33#include <asm/unistd.h>
34#include <asm/traps.h>
35#include <asm/ptrace.h>
36#include <asm/unwind.h>
37#include <asm/tls.h>
38#include <asm/system_misc.h>
39#include <asm/opcodes.h>
40
41
42static const char *handler[]= {
43 "prefetch abort",
44 "data abort",
45 "address exception",
46 "interrupt",
47 "undefined instruction",
48};
49
50void *vectors_page;
51
52#ifdef CONFIG_DEBUG_USER
53unsigned int user_debug;
54
55static int __init user_debug_setup(char *str)
56{
57 get_option(&str, &user_debug);
58 return 1;
59}
60__setup("user_debug=", user_debug_setup);
61#endif
62
63static void dump_mem(const char *, const char *, unsigned long, unsigned long);
64
65void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame)
66{
67#ifdef CONFIG_KALLSYMS
68 printk("[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from);
69#else
70 printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
71#endif
72
73 if (in_exception_text(where))
74 dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs));
75}
76
77#ifndef CONFIG_ARM_UNWIND
78/*
79 * Stack pointers should always be within the kernels view of
80 * physical memory. If it is not there, then we can't dump
81 * out any information relating to the stack.
82 */
83static int verify_stack(unsigned long sp)
84{
85 if (sp < PAGE_OFFSET ||
86 (sp > (unsigned long)high_memory && high_memory != NULL))
87 return -EFAULT;
88
89 return 0;
90}
91#endif
92
93/*
94 * Dump out the contents of some memory nicely...
95 */
96static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
97 unsigned long top)
98{
99 unsigned long first;
100 mm_segment_t fs;
101 int i;
102
103 /*
104 * We need to switch to kernel mode so that we can use __get_user
105 * to safely read from kernel space. Note that we now dump the
106 * code first, just in case the backtrace kills us.
107 */
108 fs = get_fs();
109 set_fs(KERNEL_DS);
110
111 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top);
112
113 for (first = bottom & ~31; first < top; first += 32) {
114 unsigned long p;
115 char str[sizeof(" 12345678") * 8 + 1];
116
117 memset(str, ' ', sizeof(str));
118 str[sizeof(str) - 1] = '\0';
119
120 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
121 if (p >= bottom && p < top) {
122 unsigned long val;
123 if (__get_user(val, (unsigned long *)p) == 0)
124 sprintf(str + i * 9, " %08lx", val);
125 else
126 sprintf(str + i * 9, " ????????");
127 }
128 }
129 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
130 }
131
132 set_fs(fs);
133}
134
135static void dump_instr(const char *lvl, struct pt_regs *regs)
136{
137 unsigned long addr = instruction_pointer(regs);
138 const int thumb = thumb_mode(regs);
139 const int width = thumb ? 4 : 8;
140 mm_segment_t fs;
141 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
142 int i;
143
144 /*
145 * We need to switch to kernel mode so that we can use __get_user
146 * to safely read from kernel space. Note that we now dump the
147 * code first, just in case the backtrace kills us.
148 */
149 fs = get_fs();
150 set_fs(KERNEL_DS);
151
152 for (i = -4; i < 1 + !!thumb; i++) {
153 unsigned int val, bad;
154
155 if (thumb)
156 bad = __get_user(val, &((u16 *)addr)[i]);
157 else
158 bad = __get_user(val, &((u32 *)addr)[i]);
159
160 if (!bad)
161 p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ",
162 width, val);
163 else {
164 p += sprintf(p, "bad PC value");
165 break;
166 }
167 }
168 printk("%sCode: %s\n", lvl, str);
169
170 set_fs(fs);
171}
172
173#ifdef CONFIG_ARM_UNWIND
174static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
175{
176 unwind_backtrace(regs, tsk);
177}
178#else
179static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
180{
181 unsigned int fp, mode;
182 int ok = 1;
183
184 printk("Backtrace: ");
185
186 if (!tsk)
187 tsk = current;
188
189 if (regs) {
190 fp = frame_pointer(regs);
191 mode = processor_mode(regs);
192 } else if (tsk != current) {
193 fp = thread_saved_fp(tsk);
194 mode = 0x10;
195 } else {
196 asm("mov %0, fp" : "=r" (fp) : : "cc");
197 mode = 0x10;
198 }
199
200 if (!fp) {
201 pr_cont("no frame pointer");
202 ok = 0;
203 } else if (verify_stack(fp)) {
204 pr_cont("invalid frame pointer 0x%08x", fp);
205 ok = 0;
206 } else if (fp < (unsigned long)end_of_stack(tsk))
207 pr_cont("frame pointer underflow");
208 pr_cont("\n");
209
210 if (ok)
211 c_backtrace(fp, mode);
212}
213#endif
214
215void show_stack(struct task_struct *tsk, unsigned long *sp)
216{
217 dump_backtrace(NULL, tsk);
218 barrier();
219}
220
221#ifdef CONFIG_PREEMPT
222#define S_PREEMPT " PREEMPT"
223#else
224#define S_PREEMPT ""
225#endif
226#ifdef CONFIG_SMP
227#define S_SMP " SMP"
228#else
229#define S_SMP ""
230#endif
231#ifdef CONFIG_THUMB2_KERNEL
232#define S_ISA " THUMB2"
233#else
234#define S_ISA " ARM"
235#endif
236
237static int __die(const char *str, int err, struct pt_regs *regs)
238{
239 struct task_struct *tsk = current;
240 static int die_counter;
241 int ret;
242
243 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP S_ISA "\n",
244 str, err, ++die_counter);
245
246 /* trap and error numbers are mostly meaningless on ARM */
247 ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV);
248 if (ret == NOTIFY_STOP)
249 return 1;
250
251 print_modules();
252 __show_regs(regs);
253 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
254 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk));
255
256 if (!user_mode(regs) || in_interrupt()) {
257 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp,
258 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
259 dump_backtrace(regs, tsk);
260 dump_instr(KERN_EMERG, regs);
261 }
262
263 return 0;
264}
265
266static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
267static int die_owner = -1;
268static unsigned int die_nest_count;
269
270static unsigned long oops_begin(void)
271{
272 int cpu;
273 unsigned long flags;
274
275 oops_enter();
276
277 /* racy, but better than risking deadlock. */
278 raw_local_irq_save(flags);
279 cpu = smp_processor_id();
280 if (!arch_spin_trylock(&die_lock)) {
281 if (cpu == die_owner)
282 /* nested oops. should stop eventually */;
283 else
284 arch_spin_lock(&die_lock);
285 }
286 die_nest_count++;
287 die_owner = cpu;
288 console_verbose();
289 bust_spinlocks(1);
290 return flags;
291}
292
293static void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
294{
295 if (regs && kexec_should_crash(current))
296 crash_kexec(regs);
297
298 bust_spinlocks(0);
299 die_owner = -1;
300 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
301 die_nest_count--;
302 if (!die_nest_count)
303 /* Nest count reaches zero, release the lock. */
304 arch_spin_unlock(&die_lock);
305 raw_local_irq_restore(flags);
306 oops_exit();
307
308 if (in_interrupt())
309 panic("Fatal exception in interrupt");
310 if (panic_on_oops)
311 panic("Fatal exception");
312 if (signr)
313 do_exit(signr);
314}
315
316/*
317 * This function is protected against re-entrancy.
318 */
319void die(const char *str, struct pt_regs *regs, int err)
320{
321 enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE;
322 unsigned long flags = oops_begin();
323 int sig = SIGSEGV;
324
325 if (!user_mode(regs))
326 bug_type = report_bug(regs->ARM_pc, regs);
327 if (bug_type != BUG_TRAP_TYPE_NONE)
328 str = "Oops - BUG";
329
330 if (__die(str, err, regs))
331 sig = 0;
332
333 oops_end(flags, regs, sig);
334}
335
336void arm_notify_die(const char *str, struct pt_regs *regs,
337 struct siginfo *info, unsigned long err, unsigned long trap)
338{
339 if (user_mode(regs)) {
340 current->thread.error_code = err;
341 current->thread.trap_no = trap;
342
343 force_sig_info(info->si_signo, info, current);
344 } else {
345 die(str, regs, err);
346 }
347}
348
349#ifdef CONFIG_GENERIC_BUG
350
351int is_valid_bugaddr(unsigned long pc)
352{
353#ifdef CONFIG_THUMB2_KERNEL
354 u16 bkpt;
355 u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE);
356#else
357 u32 bkpt;
358 u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE);
359#endif
360
361 if (probe_kernel_address((unsigned *)pc, bkpt))
362 return 0;
363
364 return bkpt == insn;
365}
366
367#endif
368
369static LIST_HEAD(undef_hook);
370static DEFINE_RAW_SPINLOCK(undef_lock);
371
372void register_undef_hook(struct undef_hook *hook)
373{
374 unsigned long flags;
375
376 raw_spin_lock_irqsave(&undef_lock, flags);
377 list_add(&hook->node, &undef_hook);
378 raw_spin_unlock_irqrestore(&undef_lock, flags);
379}
380
381void unregister_undef_hook(struct undef_hook *hook)
382{
383 unsigned long flags;
384
385 raw_spin_lock_irqsave(&undef_lock, flags);
386 list_del(&hook->node);
387 raw_spin_unlock_irqrestore(&undef_lock, flags);
388}
389
390static int call_undef_hook(struct pt_regs *regs, unsigned int instr)
391{
392 struct undef_hook *hook;
393 unsigned long flags;
394 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL;
395
396 raw_spin_lock_irqsave(&undef_lock, flags);
397 list_for_each_entry(hook, &undef_hook, node)
398 if ((instr & hook->instr_mask) == hook->instr_val &&
399 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val)
400 fn = hook->fn;
401 raw_spin_unlock_irqrestore(&undef_lock, flags);
402
403 return fn ? fn(regs, instr) : 1;
404}
405
406asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
407{
408 unsigned int instr;
409 siginfo_t info;
410 void __user *pc;
411
412 pc = (void __user *)instruction_pointer(regs);
413
414 if (processor_mode(regs) == SVC_MODE) {
415#ifdef CONFIG_THUMB2_KERNEL
416 if (thumb_mode(regs)) {
417 instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]);
418 if (is_wide_instruction(instr)) {
419 u16 inst2;
420 inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]);
421 instr = __opcode_thumb32_compose(instr, inst2);
422 }
423 } else
424#endif
425 instr = __mem_to_opcode_arm(*(u32 *) pc);
426 } else if (thumb_mode(regs)) {
427 if (get_user(instr, (u16 __user *)pc))
428 goto die_sig;
429 instr = __mem_to_opcode_thumb16(instr);
430 if (is_wide_instruction(instr)) {
431 unsigned int instr2;
432 if (get_user(instr2, (u16 __user *)pc+1))
433 goto die_sig;
434 instr2 = __mem_to_opcode_thumb16(instr2);
435 instr = __opcode_thumb32_compose(instr, instr2);
436 }
437 } else {
438 if (get_user(instr, (u32 __user *)pc))
439 goto die_sig;
440 instr = __mem_to_opcode_arm(instr);
441 }
442
443 if (call_undef_hook(regs, instr) == 0)
444 return;
445
446die_sig:
447#ifdef CONFIG_DEBUG_USER
448 if (user_debug & UDBG_UNDEFINED) {
449 pr_info("%s (%d): undefined instruction: pc=%p\n",
450 current->comm, task_pid_nr(current), pc);
451 __show_regs(regs);
452 dump_instr(KERN_INFO, regs);
453 }
454#endif
455
456 info.si_signo = SIGILL;
457 info.si_errno = 0;
458 info.si_code = ILL_ILLOPC;
459 info.si_addr = pc;
460
461 arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6);
462}
463
464/*
465 * Handle FIQ similarly to NMI on x86 systems.
466 *
467 * The runtime environment for NMIs is extremely restrictive
468 * (NMIs can pre-empt critical sections meaning almost all locking is
469 * forbidden) meaning this default FIQ handling must only be used in
470 * circumstances where non-maskability improves robustness, such as
471 * watchdog or debug logic.
472 *
473 * This handler is not appropriate for general purpose use in drivers
474 * platform code and can be overrideen using set_fiq_handler.
475 */
476asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs)
477{
478 struct pt_regs *old_regs = set_irq_regs(regs);
479
480 nmi_enter();
481
482 /* nop. FIQ handlers for special arch/arm features can be added here. */
483
484 nmi_exit();
485
486 set_irq_regs(old_regs);
487}
488
489/*
490 * bad_mode handles the impossible case in the vectors. If you see one of
491 * these, then it's extremely serious, and could mean you have buggy hardware.
492 * It never returns, and never tries to sync. We hope that we can at least
493 * dump out some state information...
494 */
495asmlinkage void bad_mode(struct pt_regs *regs, int reason)
496{
497 console_verbose();
498
499 pr_crit("Bad mode in %s handler detected\n", handler[reason]);
500
501 die("Oops - bad mode", regs, 0);
502 local_irq_disable();
503 panic("bad mode");
504}
505
506static int bad_syscall(int n, struct pt_regs *regs)
507{
508 siginfo_t info;
509
510 if ((current->personality & PER_MASK) != PER_LINUX) {
511 send_sig(SIGSEGV, current, 1);
512 return regs->ARM_r0;
513 }
514
515#ifdef CONFIG_DEBUG_USER
516 if (user_debug & UDBG_SYSCALL) {
517 pr_err("[%d] %s: obsolete system call %08x.\n",
518 task_pid_nr(current), current->comm, n);
519 dump_instr(KERN_ERR, regs);
520 }
521#endif
522
523 info.si_signo = SIGILL;
524 info.si_errno = 0;
525 info.si_code = ILL_ILLTRP;
526 info.si_addr = (void __user *)instruction_pointer(regs) -
527 (thumb_mode(regs) ? 2 : 4);
528
529 arm_notify_die("Oops - bad syscall", regs, &info, n, 0);
530
531 return regs->ARM_r0;
532}
533
534static inline int
535__do_cache_op(unsigned long start, unsigned long end)
536{
537 int ret;
538
539 do {
540 unsigned long chunk = min(PAGE_SIZE, end - start);
541
542 if (fatal_signal_pending(current))
543 return 0;
544
545 ret = flush_cache_user_range(start, start + chunk);
546 if (ret)
547 return ret;
548
549 cond_resched();
550 start += chunk;
551 } while (start < end);
552
553 return 0;
554}
555
556static inline int
557do_cache_op(unsigned long start, unsigned long end, int flags)
558{
559 if (end < start || flags)
560 return -EINVAL;
561
562 if (!access_ok(VERIFY_READ, start, end - start))
563 return -EFAULT;
564
565 return __do_cache_op(start, end);
566}
567
568/*
569 * Handle all unrecognised system calls.
570 * 0x9f0000 - 0x9fffff are some more esoteric system calls
571 */
572#define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
573asmlinkage int arm_syscall(int no, struct pt_regs *regs)
574{
575 siginfo_t info;
576
577 if ((no >> 16) != (__ARM_NR_BASE>> 16))
578 return bad_syscall(no, regs);
579
580 switch (no & 0xffff) {
581 case 0: /* branch through 0 */
582 info.si_signo = SIGSEGV;
583 info.si_errno = 0;
584 info.si_code = SEGV_MAPERR;
585 info.si_addr = NULL;
586
587 arm_notify_die("branch through zero", regs, &info, 0, 0);
588 return 0;
589
590 case NR(breakpoint): /* SWI BREAK_POINT */
591 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
592 ptrace_break(current, regs);
593 return regs->ARM_r0;
594
595 /*
596 * Flush a region from virtual address 'r0' to virtual address 'r1'
597 * _exclusive_. There is no alignment requirement on either address;
598 * user space does not need to know the hardware cache layout.
599 *
600 * r2 contains flags. It should ALWAYS be passed as ZERO until it
601 * is defined to be something else. For now we ignore it, but may
602 * the fires of hell burn in your belly if you break this rule. ;)
603 *
604 * (at a later date, we may want to allow this call to not flush
605 * various aspects of the cache. Passing '0' will guarantee that
606 * everything necessary gets flushed to maintain consistency in
607 * the specified region).
608 */
609 case NR(cacheflush):
610 return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
611
612 case NR(usr26):
613 if (!(elf_hwcap & HWCAP_26BIT))
614 break;
615 regs->ARM_cpsr &= ~MODE32_BIT;
616 return regs->ARM_r0;
617
618 case NR(usr32):
619 if (!(elf_hwcap & HWCAP_26BIT))
620 break;
621 regs->ARM_cpsr |= MODE32_BIT;
622 return regs->ARM_r0;
623
624 case NR(set_tls):
625 set_tls(regs->ARM_r0);
626 return 0;
627
628 default:
629 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS
630 if not implemented, rather than raising SIGILL. This
631 way the calling program can gracefully determine whether
632 a feature is supported. */
633 if ((no & 0xffff) <= 0x7ff)
634 return -ENOSYS;
635 break;
636 }
637#ifdef CONFIG_DEBUG_USER
638 /*
639 * experience shows that these seem to indicate that
640 * something catastrophic has happened
641 */
642 if (user_debug & UDBG_SYSCALL) {
643 pr_err("[%d] %s: arm syscall %d\n",
644 task_pid_nr(current), current->comm, no);
645 dump_instr("", regs);
646 if (user_mode(regs)) {
647 __show_regs(regs);
648 c_backtrace(frame_pointer(regs), processor_mode(regs));
649 }
650 }
651#endif
652 info.si_signo = SIGILL;
653 info.si_errno = 0;
654 info.si_code = ILL_ILLTRP;
655 info.si_addr = (void __user *)instruction_pointer(regs) -
656 (thumb_mode(regs) ? 2 : 4);
657
658 arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0);
659 return 0;
660}
661
662#ifdef CONFIG_TLS_REG_EMUL
663
664/*
665 * We might be running on an ARMv6+ processor which should have the TLS
666 * register but for some reason we can't use it, or maybe an SMP system
667 * using a pre-ARMv6 processor (there are apparently a few prototypes like
668 * that in existence) and therefore access to that register must be
669 * emulated.
670 */
671
672static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
673{
674 int reg = (instr >> 12) & 15;
675 if (reg == 15)
676 return 1;
677 regs->uregs[reg] = current_thread_info()->tp_value[0];
678 regs->ARM_pc += 4;
679 return 0;
680}
681
682static struct undef_hook arm_mrc_hook = {
683 .instr_mask = 0x0fff0fff,
684 .instr_val = 0x0e1d0f70,
685 .cpsr_mask = PSR_T_BIT,
686 .cpsr_val = 0,
687 .fn = get_tp_trap,
688};
689
690static int __init arm_mrc_hook_init(void)
691{
692 register_undef_hook(&arm_mrc_hook);
693 return 0;
694}
695
696late_initcall(arm_mrc_hook_init);
697
698#endif
699
700/*
701 * A data abort trap was taken, but we did not handle the instruction.
702 * Try to abort the user program, or panic if it was the kernel.
703 */
704asmlinkage void
705baddataabort(int code, unsigned long instr, struct pt_regs *regs)
706{
707 unsigned long addr = instruction_pointer(regs);
708 siginfo_t info;
709
710#ifdef CONFIG_DEBUG_USER
711 if (user_debug & UDBG_BADABORT) {
712 pr_err("[%d] %s: bad data abort: code %d instr 0x%08lx\n",
713 task_pid_nr(current), current->comm, code, instr);
714 dump_instr(KERN_ERR, regs);
715 show_pte(current->mm, addr);
716 }
717#endif
718
719 info.si_signo = SIGILL;
720 info.si_errno = 0;
721 info.si_code = ILL_ILLOPC;
722 info.si_addr = (void __user *)addr;
723
724 arm_notify_die("unknown data abort code", regs, &info, instr, 0);
725}
726
727void __readwrite_bug(const char *fn)
728{
729 pr_err("%s called, but not implemented\n", fn);
730 BUG();
731}
732EXPORT_SYMBOL(__readwrite_bug);
733
734void __pte_error(const char *file, int line, pte_t pte)
735{
736 pr_err("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte));
737}
738
739void __pmd_error(const char *file, int line, pmd_t pmd)
740{
741 pr_err("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd));
742}
743
744void __pgd_error(const char *file, int line, pgd_t pgd)
745{
746 pr_err("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd));
747}
748
749asmlinkage void __div0(void)
750{
751 pr_err("Division by zero in kernel.\n");
752 dump_stack();
753}
754EXPORT_SYMBOL(__div0);
755
756void abort(void)
757{
758 BUG();
759
760 /* if that doesn't kill us, halt */
761 panic("Oops failed to kill thread");
762}
763EXPORT_SYMBOL(abort);
764
765void __init trap_init(void)
766{
767 return;
768}
769
770#ifdef CONFIG_KUSER_HELPERS
771static void __init kuser_init(void *vectors)
772{
773 extern char __kuser_helper_start[], __kuser_helper_end[];
774 int kuser_sz = __kuser_helper_end - __kuser_helper_start;
775
776 memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
777
778 /*
779 * vectors + 0xfe0 = __kuser_get_tls
780 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8
781 */
782 if (tls_emu || has_tls_reg)
783 memcpy(vectors + 0xfe0, vectors + 0xfe8, 4);
784}
785#else
786static inline void __init kuser_init(void *vectors)
787{
788}
789#endif
790
791void __init early_trap_init(void *vectors_base)
792{
793#ifndef CONFIG_CPU_V7M
794 unsigned long vectors = (unsigned long)vectors_base;
795 extern char __stubs_start[], __stubs_end[];
796 extern char __vectors_start[], __vectors_end[];
797 unsigned i;
798
799 vectors_page = vectors_base;
800
801 /*
802 * Poison the vectors page with an undefined instruction. This
803 * instruction is chosen to be undefined for both ARM and Thumb
804 * ISAs. The Thumb version is an undefined instruction with a
805 * branch back to the undefined instruction.
806 */
807 for (i = 0; i < PAGE_SIZE / sizeof(u32); i++)
808 ((u32 *)vectors_base)[i] = 0xe7fddef1;
809
810 /*
811 * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
812 * into the vector page, mapped at 0xffff0000, and ensure these
813 * are visible to the instruction stream.
814 */
815 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
816 memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start);
817
818 kuser_init(vectors_base);
819
820 flush_icache_range(vectors, vectors + PAGE_SIZE * 2);
821#else /* ifndef CONFIG_CPU_V7M */
822 /*
823 * on V7-M there is no need to copy the vector table to a dedicated
824 * memory area. The address is configurable and so a table in the kernel
825 * image can be used.
826 */
827#endif
828}
1/*
2 * linux/arch/arm/kernel/traps.c
3 *
4 * Copyright (C) 1995-2009 Russell King
5 * Fragments that appear the same as linux/arch/i386/kernel/traps.c (C) Linus Torvalds
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * 'traps.c' handles hardware exceptions after we have saved some state in
12 * 'linux/arch/arm/lib/traps.S'. Mostly a debugging aid, but will probably
13 * kill the offending process.
14 */
15#include <linux/signal.h>
16#include <linux/personality.h>
17#include <linux/kallsyms.h>
18#include <linux/spinlock.h>
19#include <linux/uaccess.h>
20#include <linux/hardirq.h>
21#include <linux/kdebug.h>
22#include <linux/kprobes.h>
23#include <linux/module.h>
24#include <linux/kexec.h>
25#include <linux/bug.h>
26#include <linux/delay.h>
27#include <linux/init.h>
28#include <linux/sched/signal.h>
29#include <linux/sched/debug.h>
30#include <linux/sched/task_stack.h>
31#include <linux/irq.h>
32
33#include <linux/atomic.h>
34#include <asm/cacheflush.h>
35#include <asm/exception.h>
36#include <asm/unistd.h>
37#include <asm/traps.h>
38#include <asm/ptrace.h>
39#include <asm/unwind.h>
40#include <asm/tls.h>
41#include <asm/system_misc.h>
42#include <asm/opcodes.h>
43
44
45static const char *handler[]= {
46 "prefetch abort",
47 "data abort",
48 "address exception",
49 "interrupt",
50 "undefined instruction",
51};
52
53void *vectors_page;
54
55#ifdef CONFIG_DEBUG_USER
56unsigned int user_debug;
57
58static int __init user_debug_setup(char *str)
59{
60 get_option(&str, &user_debug);
61 return 1;
62}
63__setup("user_debug=", user_debug_setup);
64#endif
65
66static void dump_mem(const char *, const char *, unsigned long, unsigned long);
67
68void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame)
69{
70#ifdef CONFIG_KALLSYMS
71 printk("[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from);
72#else
73 printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
74#endif
75
76 if (in_entry_text(from))
77 dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs));
78}
79
80void dump_backtrace_stm(u32 *stack, u32 instruction)
81{
82 char str[80], *p;
83 unsigned int x;
84 int reg;
85
86 for (reg = 10, x = 0, p = str; reg >= 0; reg--) {
87 if (instruction & BIT(reg)) {
88 p += sprintf(p, " r%d:%08x", reg, *stack--);
89 if (++x == 6) {
90 x = 0;
91 p = str;
92 printk("%s\n", str);
93 }
94 }
95 }
96 if (p != str)
97 printk("%s\n", str);
98}
99
100#ifndef CONFIG_ARM_UNWIND
101/*
102 * Stack pointers should always be within the kernels view of
103 * physical memory. If it is not there, then we can't dump
104 * out any information relating to the stack.
105 */
106static int verify_stack(unsigned long sp)
107{
108 if (sp < PAGE_OFFSET ||
109 (sp > (unsigned long)high_memory && high_memory != NULL))
110 return -EFAULT;
111
112 return 0;
113}
114#endif
115
116/*
117 * Dump out the contents of some memory nicely...
118 */
119static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
120 unsigned long top)
121{
122 unsigned long first;
123 mm_segment_t fs;
124 int i;
125
126 /*
127 * We need to switch to kernel mode so that we can use __get_user
128 * to safely read from kernel space. Note that we now dump the
129 * code first, just in case the backtrace kills us.
130 */
131 fs = get_fs();
132 set_fs(KERNEL_DS);
133
134 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top);
135
136 for (first = bottom & ~31; first < top; first += 32) {
137 unsigned long p;
138 char str[sizeof(" 12345678") * 8 + 1];
139
140 memset(str, ' ', sizeof(str));
141 str[sizeof(str) - 1] = '\0';
142
143 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
144 if (p >= bottom && p < top) {
145 unsigned long val;
146 if (__get_user(val, (unsigned long *)p) == 0)
147 sprintf(str + i * 9, " %08lx", val);
148 else
149 sprintf(str + i * 9, " ????????");
150 }
151 }
152 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
153 }
154
155 set_fs(fs);
156}
157
158static void __dump_instr(const char *lvl, struct pt_regs *regs)
159{
160 unsigned long addr = instruction_pointer(regs);
161 const int thumb = thumb_mode(regs);
162 const int width = thumb ? 4 : 8;
163 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
164 int i;
165
166 /*
167 * Note that we now dump the code first, just in case the backtrace
168 * kills us.
169 */
170
171 for (i = -4; i < 1 + !!thumb; i++) {
172 unsigned int val, bad;
173
174 if (thumb)
175 bad = get_user(val, &((u16 *)addr)[i]);
176 else
177 bad = get_user(val, &((u32 *)addr)[i]);
178
179 if (!bad)
180 p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ",
181 width, val);
182 else {
183 p += sprintf(p, "bad PC value");
184 break;
185 }
186 }
187 printk("%sCode: %s\n", lvl, str);
188}
189
190static void dump_instr(const char *lvl, struct pt_regs *regs)
191{
192 mm_segment_t fs;
193
194 if (!user_mode(regs)) {
195 fs = get_fs();
196 set_fs(KERNEL_DS);
197 __dump_instr(lvl, regs);
198 set_fs(fs);
199 } else {
200 __dump_instr(lvl, regs);
201 }
202}
203
204#ifdef CONFIG_ARM_UNWIND
205static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
206{
207 unwind_backtrace(regs, tsk);
208}
209#else
210static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
211{
212 unsigned int fp, mode;
213 int ok = 1;
214
215 printk("Backtrace: ");
216
217 if (!tsk)
218 tsk = current;
219
220 if (regs) {
221 fp = frame_pointer(regs);
222 mode = processor_mode(regs);
223 } else if (tsk != current) {
224 fp = thread_saved_fp(tsk);
225 mode = 0x10;
226 } else {
227 asm("mov %0, fp" : "=r" (fp) : : "cc");
228 mode = 0x10;
229 }
230
231 if (!fp) {
232 pr_cont("no frame pointer");
233 ok = 0;
234 } else if (verify_stack(fp)) {
235 pr_cont("invalid frame pointer 0x%08x", fp);
236 ok = 0;
237 } else if (fp < (unsigned long)end_of_stack(tsk))
238 pr_cont("frame pointer underflow");
239 pr_cont("\n");
240
241 if (ok)
242 c_backtrace(fp, mode);
243}
244#endif
245
246void show_stack(struct task_struct *tsk, unsigned long *sp)
247{
248 dump_backtrace(NULL, tsk);
249 barrier();
250}
251
252#ifdef CONFIG_PREEMPT
253#define S_PREEMPT " PREEMPT"
254#else
255#define S_PREEMPT ""
256#endif
257#ifdef CONFIG_SMP
258#define S_SMP " SMP"
259#else
260#define S_SMP ""
261#endif
262#ifdef CONFIG_THUMB2_KERNEL
263#define S_ISA " THUMB2"
264#else
265#define S_ISA " ARM"
266#endif
267
268static int __die(const char *str, int err, struct pt_regs *regs)
269{
270 struct task_struct *tsk = current;
271 static int die_counter;
272 int ret;
273
274 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP S_ISA "\n",
275 str, err, ++die_counter);
276
277 /* trap and error numbers are mostly meaningless on ARM */
278 ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV);
279 if (ret == NOTIFY_STOP)
280 return 1;
281
282 print_modules();
283 __show_regs(regs);
284 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
285 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk));
286
287 if (!user_mode(regs) || in_interrupt()) {
288 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp,
289 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
290 dump_backtrace(regs, tsk);
291 dump_instr(KERN_EMERG, regs);
292 }
293
294 return 0;
295}
296
297static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
298static int die_owner = -1;
299static unsigned int die_nest_count;
300
301static unsigned long oops_begin(void)
302{
303 int cpu;
304 unsigned long flags;
305
306 oops_enter();
307
308 /* racy, but better than risking deadlock. */
309 raw_local_irq_save(flags);
310 cpu = smp_processor_id();
311 if (!arch_spin_trylock(&die_lock)) {
312 if (cpu == die_owner)
313 /* nested oops. should stop eventually */;
314 else
315 arch_spin_lock(&die_lock);
316 }
317 die_nest_count++;
318 die_owner = cpu;
319 console_verbose();
320 bust_spinlocks(1);
321 return flags;
322}
323
324static void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
325{
326 if (regs && kexec_should_crash(current))
327 crash_kexec(regs);
328
329 bust_spinlocks(0);
330 die_owner = -1;
331 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
332 die_nest_count--;
333 if (!die_nest_count)
334 /* Nest count reaches zero, release the lock. */
335 arch_spin_unlock(&die_lock);
336 raw_local_irq_restore(flags);
337 oops_exit();
338
339 if (in_interrupt())
340 panic("Fatal exception in interrupt");
341 if (panic_on_oops)
342 panic("Fatal exception");
343 if (signr)
344 do_exit(signr);
345}
346
347/*
348 * This function is protected against re-entrancy.
349 */
350void die(const char *str, struct pt_regs *regs, int err)
351{
352 enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE;
353 unsigned long flags = oops_begin();
354 int sig = SIGSEGV;
355
356 if (!user_mode(regs))
357 bug_type = report_bug(regs->ARM_pc, regs);
358 if (bug_type != BUG_TRAP_TYPE_NONE)
359 str = "Oops - BUG";
360
361 if (__die(str, err, regs))
362 sig = 0;
363
364 oops_end(flags, regs, sig);
365}
366
367void arm_notify_die(const char *str, struct pt_regs *regs,
368 struct siginfo *info, unsigned long err, unsigned long trap)
369{
370 if (user_mode(regs)) {
371 current->thread.error_code = err;
372 current->thread.trap_no = trap;
373
374 force_sig_info(info->si_signo, info, current);
375 } else {
376 die(str, regs, err);
377 }
378}
379
380#ifdef CONFIG_GENERIC_BUG
381
382int is_valid_bugaddr(unsigned long pc)
383{
384#ifdef CONFIG_THUMB2_KERNEL
385 u16 bkpt;
386 u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE);
387#else
388 u32 bkpt;
389 u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE);
390#endif
391
392 if (probe_kernel_address((unsigned *)pc, bkpt))
393 return 0;
394
395 return bkpt == insn;
396}
397
398#endif
399
400static LIST_HEAD(undef_hook);
401static DEFINE_RAW_SPINLOCK(undef_lock);
402
403void register_undef_hook(struct undef_hook *hook)
404{
405 unsigned long flags;
406
407 raw_spin_lock_irqsave(&undef_lock, flags);
408 list_add(&hook->node, &undef_hook);
409 raw_spin_unlock_irqrestore(&undef_lock, flags);
410}
411
412void unregister_undef_hook(struct undef_hook *hook)
413{
414 unsigned long flags;
415
416 raw_spin_lock_irqsave(&undef_lock, flags);
417 list_del(&hook->node);
418 raw_spin_unlock_irqrestore(&undef_lock, flags);
419}
420
421static nokprobe_inline
422int call_undef_hook(struct pt_regs *regs, unsigned int instr)
423{
424 struct undef_hook *hook;
425 unsigned long flags;
426 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL;
427
428 raw_spin_lock_irqsave(&undef_lock, flags);
429 list_for_each_entry(hook, &undef_hook, node)
430 if ((instr & hook->instr_mask) == hook->instr_val &&
431 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val)
432 fn = hook->fn;
433 raw_spin_unlock_irqrestore(&undef_lock, flags);
434
435 return fn ? fn(regs, instr) : 1;
436}
437
438asmlinkage void do_undefinstr(struct pt_regs *regs)
439{
440 unsigned int instr;
441 siginfo_t info;
442 void __user *pc;
443
444 pc = (void __user *)instruction_pointer(regs);
445
446 if (processor_mode(regs) == SVC_MODE) {
447#ifdef CONFIG_THUMB2_KERNEL
448 if (thumb_mode(regs)) {
449 instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]);
450 if (is_wide_instruction(instr)) {
451 u16 inst2;
452 inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]);
453 instr = __opcode_thumb32_compose(instr, inst2);
454 }
455 } else
456#endif
457 instr = __mem_to_opcode_arm(*(u32 *) pc);
458 } else if (thumb_mode(regs)) {
459 if (get_user(instr, (u16 __user *)pc))
460 goto die_sig;
461 instr = __mem_to_opcode_thumb16(instr);
462 if (is_wide_instruction(instr)) {
463 unsigned int instr2;
464 if (get_user(instr2, (u16 __user *)pc+1))
465 goto die_sig;
466 instr2 = __mem_to_opcode_thumb16(instr2);
467 instr = __opcode_thumb32_compose(instr, instr2);
468 }
469 } else {
470 if (get_user(instr, (u32 __user *)pc))
471 goto die_sig;
472 instr = __mem_to_opcode_arm(instr);
473 }
474
475 if (call_undef_hook(regs, instr) == 0)
476 return;
477
478die_sig:
479#ifdef CONFIG_DEBUG_USER
480 if (user_debug & UDBG_UNDEFINED) {
481 pr_info("%s (%d): undefined instruction: pc=%p\n",
482 current->comm, task_pid_nr(current), pc);
483 __show_regs(regs);
484 dump_instr(KERN_INFO, regs);
485 }
486#endif
487
488 info.si_signo = SIGILL;
489 info.si_errno = 0;
490 info.si_code = ILL_ILLOPC;
491 info.si_addr = pc;
492
493 arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6);
494}
495NOKPROBE_SYMBOL(do_undefinstr)
496
497/*
498 * Handle FIQ similarly to NMI on x86 systems.
499 *
500 * The runtime environment for NMIs is extremely restrictive
501 * (NMIs can pre-empt critical sections meaning almost all locking is
502 * forbidden) meaning this default FIQ handling must only be used in
503 * circumstances where non-maskability improves robustness, such as
504 * watchdog or debug logic.
505 *
506 * This handler is not appropriate for general purpose use in drivers
507 * platform code and can be overrideen using set_fiq_handler.
508 */
509asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs)
510{
511 struct pt_regs *old_regs = set_irq_regs(regs);
512
513 nmi_enter();
514
515 /* nop. FIQ handlers for special arch/arm features can be added here. */
516
517 nmi_exit();
518
519 set_irq_regs(old_regs);
520}
521
522/*
523 * bad_mode handles the impossible case in the vectors. If you see one of
524 * these, then it's extremely serious, and could mean you have buggy hardware.
525 * It never returns, and never tries to sync. We hope that we can at least
526 * dump out some state information...
527 */
528asmlinkage void bad_mode(struct pt_regs *regs, int reason)
529{
530 console_verbose();
531
532 pr_crit("Bad mode in %s handler detected\n", handler[reason]);
533
534 die("Oops - bad mode", regs, 0);
535 local_irq_disable();
536 panic("bad mode");
537}
538
539static int bad_syscall(int n, struct pt_regs *regs)
540{
541 siginfo_t info;
542
543 if ((current->personality & PER_MASK) != PER_LINUX) {
544 send_sig(SIGSEGV, current, 1);
545 return regs->ARM_r0;
546 }
547
548#ifdef CONFIG_DEBUG_USER
549 if (user_debug & UDBG_SYSCALL) {
550 pr_err("[%d] %s: obsolete system call %08x.\n",
551 task_pid_nr(current), current->comm, n);
552 dump_instr(KERN_ERR, regs);
553 }
554#endif
555
556 info.si_signo = SIGILL;
557 info.si_errno = 0;
558 info.si_code = ILL_ILLTRP;
559 info.si_addr = (void __user *)instruction_pointer(regs) -
560 (thumb_mode(regs) ? 2 : 4);
561
562 arm_notify_die("Oops - bad syscall", regs, &info, n, 0);
563
564 return regs->ARM_r0;
565}
566
567static inline int
568__do_cache_op(unsigned long start, unsigned long end)
569{
570 int ret;
571
572 do {
573 unsigned long chunk = min(PAGE_SIZE, end - start);
574
575 if (fatal_signal_pending(current))
576 return 0;
577
578 ret = flush_cache_user_range(start, start + chunk);
579 if (ret)
580 return ret;
581
582 cond_resched();
583 start += chunk;
584 } while (start < end);
585
586 return 0;
587}
588
589static inline int
590do_cache_op(unsigned long start, unsigned long end, int flags)
591{
592 if (end < start || flags)
593 return -EINVAL;
594
595 if (!access_ok(VERIFY_READ, start, end - start))
596 return -EFAULT;
597
598 return __do_cache_op(start, end);
599}
600
601/*
602 * Handle all unrecognised system calls.
603 * 0x9f0000 - 0x9fffff are some more esoteric system calls
604 */
605#define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
606asmlinkage int arm_syscall(int no, struct pt_regs *regs)
607{
608 siginfo_t info;
609
610 if ((no >> 16) != (__ARM_NR_BASE>> 16))
611 return bad_syscall(no, regs);
612
613 switch (no & 0xffff) {
614 case 0: /* branch through 0 */
615 info.si_signo = SIGSEGV;
616 info.si_errno = 0;
617 info.si_code = SEGV_MAPERR;
618 info.si_addr = NULL;
619
620 arm_notify_die("branch through zero", regs, &info, 0, 0);
621 return 0;
622
623 case NR(breakpoint): /* SWI BREAK_POINT */
624 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
625 ptrace_break(current, regs);
626 return regs->ARM_r0;
627
628 /*
629 * Flush a region from virtual address 'r0' to virtual address 'r1'
630 * _exclusive_. There is no alignment requirement on either address;
631 * user space does not need to know the hardware cache layout.
632 *
633 * r2 contains flags. It should ALWAYS be passed as ZERO until it
634 * is defined to be something else. For now we ignore it, but may
635 * the fires of hell burn in your belly if you break this rule. ;)
636 *
637 * (at a later date, we may want to allow this call to not flush
638 * various aspects of the cache. Passing '0' will guarantee that
639 * everything necessary gets flushed to maintain consistency in
640 * the specified region).
641 */
642 case NR(cacheflush):
643 return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
644
645 case NR(usr26):
646 if (!(elf_hwcap & HWCAP_26BIT))
647 break;
648 regs->ARM_cpsr &= ~MODE32_BIT;
649 return regs->ARM_r0;
650
651 case NR(usr32):
652 if (!(elf_hwcap & HWCAP_26BIT))
653 break;
654 regs->ARM_cpsr |= MODE32_BIT;
655 return regs->ARM_r0;
656
657 case NR(set_tls):
658 set_tls(regs->ARM_r0);
659 return 0;
660
661 case NR(get_tls):
662 return current_thread_info()->tp_value[0];
663
664 default:
665 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS
666 if not implemented, rather than raising SIGILL. This
667 way the calling program can gracefully determine whether
668 a feature is supported. */
669 if ((no & 0xffff) <= 0x7ff)
670 return -ENOSYS;
671 break;
672 }
673#ifdef CONFIG_DEBUG_USER
674 /*
675 * experience shows that these seem to indicate that
676 * something catastrophic has happened
677 */
678 if (user_debug & UDBG_SYSCALL) {
679 pr_err("[%d] %s: arm syscall %d\n",
680 task_pid_nr(current), current->comm, no);
681 dump_instr("", regs);
682 if (user_mode(regs)) {
683 __show_regs(regs);
684 c_backtrace(frame_pointer(regs), processor_mode(regs));
685 }
686 }
687#endif
688 info.si_signo = SIGILL;
689 info.si_errno = 0;
690 info.si_code = ILL_ILLTRP;
691 info.si_addr = (void __user *)instruction_pointer(regs) -
692 (thumb_mode(regs) ? 2 : 4);
693
694 arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0);
695 return 0;
696}
697
698#ifdef CONFIG_TLS_REG_EMUL
699
700/*
701 * We might be running on an ARMv6+ processor which should have the TLS
702 * register but for some reason we can't use it, or maybe an SMP system
703 * using a pre-ARMv6 processor (there are apparently a few prototypes like
704 * that in existence) and therefore access to that register must be
705 * emulated.
706 */
707
708static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
709{
710 int reg = (instr >> 12) & 15;
711 if (reg == 15)
712 return 1;
713 regs->uregs[reg] = current_thread_info()->tp_value[0];
714 regs->ARM_pc += 4;
715 return 0;
716}
717
718static struct undef_hook arm_mrc_hook = {
719 .instr_mask = 0x0fff0fff,
720 .instr_val = 0x0e1d0f70,
721 .cpsr_mask = PSR_T_BIT,
722 .cpsr_val = 0,
723 .fn = get_tp_trap,
724};
725
726static int __init arm_mrc_hook_init(void)
727{
728 register_undef_hook(&arm_mrc_hook);
729 return 0;
730}
731
732late_initcall(arm_mrc_hook_init);
733
734#endif
735
736/*
737 * A data abort trap was taken, but we did not handle the instruction.
738 * Try to abort the user program, or panic if it was the kernel.
739 */
740asmlinkage void
741baddataabort(int code, unsigned long instr, struct pt_regs *regs)
742{
743 unsigned long addr = instruction_pointer(regs);
744 siginfo_t info;
745
746#ifdef CONFIG_DEBUG_USER
747 if (user_debug & UDBG_BADABORT) {
748 pr_err("[%d] %s: bad data abort: code %d instr 0x%08lx\n",
749 task_pid_nr(current), current->comm, code, instr);
750 dump_instr(KERN_ERR, regs);
751 show_pte(current->mm, addr);
752 }
753#endif
754
755 info.si_signo = SIGILL;
756 info.si_errno = 0;
757 info.si_code = ILL_ILLOPC;
758 info.si_addr = (void __user *)addr;
759
760 arm_notify_die("unknown data abort code", regs, &info, instr, 0);
761}
762
763void __readwrite_bug(const char *fn)
764{
765 pr_err("%s called, but not implemented\n", fn);
766 BUG();
767}
768EXPORT_SYMBOL(__readwrite_bug);
769
770void __pte_error(const char *file, int line, pte_t pte)
771{
772 pr_err("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte));
773}
774
775void __pmd_error(const char *file, int line, pmd_t pmd)
776{
777 pr_err("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd));
778}
779
780void __pgd_error(const char *file, int line, pgd_t pgd)
781{
782 pr_err("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd));
783}
784
785asmlinkage void __div0(void)
786{
787 pr_err("Division by zero in kernel.\n");
788 dump_stack();
789}
790EXPORT_SYMBOL(__div0);
791
792void abort(void)
793{
794 BUG();
795
796 /* if that doesn't kill us, halt */
797 panic("Oops failed to kill thread");
798}
799
800void __init trap_init(void)
801{
802 return;
803}
804
805#ifdef CONFIG_KUSER_HELPERS
806static void __init kuser_init(void *vectors)
807{
808 extern char __kuser_helper_start[], __kuser_helper_end[];
809 int kuser_sz = __kuser_helper_end - __kuser_helper_start;
810
811 memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
812
813 /*
814 * vectors + 0xfe0 = __kuser_get_tls
815 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8
816 */
817 if (tls_emu || has_tls_reg)
818 memcpy(vectors + 0xfe0, vectors + 0xfe8, 4);
819}
820#else
821static inline void __init kuser_init(void *vectors)
822{
823}
824#endif
825
826void __init early_trap_init(void *vectors_base)
827{
828#ifndef CONFIG_CPU_V7M
829 unsigned long vectors = (unsigned long)vectors_base;
830 extern char __stubs_start[], __stubs_end[];
831 extern char __vectors_start[], __vectors_end[];
832 unsigned i;
833
834 vectors_page = vectors_base;
835
836 /*
837 * Poison the vectors page with an undefined instruction. This
838 * instruction is chosen to be undefined for both ARM and Thumb
839 * ISAs. The Thumb version is an undefined instruction with a
840 * branch back to the undefined instruction.
841 */
842 for (i = 0; i < PAGE_SIZE / sizeof(u32); i++)
843 ((u32 *)vectors_base)[i] = 0xe7fddef1;
844
845 /*
846 * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
847 * into the vector page, mapped at 0xffff0000, and ensure these
848 * are visible to the instruction stream.
849 */
850 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
851 memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start);
852
853 kuser_init(vectors_base);
854
855 flush_icache_range(vectors, vectors + PAGE_SIZE * 2);
856#else /* ifndef CONFIG_CPU_V7M */
857 /*
858 * on V7-M there is no need to copy the vector table to a dedicated
859 * memory area. The address is configurable and so a table in the kernel
860 * image can be used.
861 */
862#endif
863}