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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// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/arch/arm/kernel/traps.c
4 *
5 * Copyright (C) 1995-2009 Russell King
6 * Fragments that appear the same as linux/arch/i386/kernel/traps.c (C) Linus Torvalds
7 *
8 * 'traps.c' handles hardware exceptions after we have saved some state in
9 * 'linux/arch/arm/lib/traps.S'. Mostly a debugging aid, but will probably
10 * kill the offending process.
11 */
12#include <linux/signal.h>
13#include <linux/personality.h>
14#include <linux/kallsyms.h>
15#include <linux/spinlock.h>
16#include <linux/uaccess.h>
17#include <linux/hardirq.h>
18#include <linux/kdebug.h>
19#include <linux/kprobes.h>
20#include <linux/module.h>
21#include <linux/kexec.h>
22#include <linux/bug.h>
23#include <linux/delay.h>
24#include <linux/init.h>
25#include <linux/sched/signal.h>
26#include <linux/sched/debug.h>
27#include <linux/sched/task_stack.h>
28#include <linux/irq.h>
29
30#include <linux/atomic.h>
31#include <asm/cacheflush.h>
32#include <asm/exception.h>
33#include <asm/unistd.h>
34#include <asm/traps.h>
35#include <asm/ptrace.h>
36#include <asm/unwind.h>
37#include <asm/tls.h>
38#include <asm/system_misc.h>
39#include <asm/opcodes.h>
40
41
42static const char *handler[]= {
43 "prefetch abort",
44 "data abort",
45 "address exception",
46 "interrupt",
47 "undefined instruction",
48};
49
50void *vectors_page;
51
52#ifdef CONFIG_DEBUG_USER
53unsigned int user_debug;
54
55static int __init user_debug_setup(char *str)
56{
57 get_option(&str, &user_debug);
58 return 1;
59}
60__setup("user_debug=", user_debug_setup);
61#endif
62
63static void dump_mem(const char *, const char *, unsigned long, unsigned long);
64
65void dump_backtrace_entry(unsigned long where, unsigned long from,
66 unsigned long frame, const char *loglvl)
67{
68 unsigned long end = frame + 4 + sizeof(struct pt_regs);
69
70#ifdef CONFIG_KALLSYMS
71 printk("%s[<%08lx>] (%ps) from [<%08lx>] (%pS)\n",
72 loglvl, where, (void *)where, from, (void *)from);
73#else
74 printk("%sFunction entered at [<%08lx>] from [<%08lx>]\n",
75 loglvl, where, from);
76#endif
77
78 if (in_entry_text(from) && end <= ALIGN(frame, THREAD_SIZE))
79 dump_mem(loglvl, "Exception stack", frame + 4, end);
80}
81
82void dump_backtrace_stm(u32 *stack, u32 instruction, const char *loglvl)
83{
84 char str[80], *p;
85 unsigned int x;
86 int reg;
87
88 for (reg = 10, x = 0, p = str; reg >= 0; reg--) {
89 if (instruction & BIT(reg)) {
90 p += sprintf(p, " r%d:%08x", reg, *stack--);
91 if (++x == 6) {
92 x = 0;
93 p = str;
94 printk("%s%s\n", loglvl, str);
95 }
96 }
97 }
98 if (p != str)
99 printk("%s%s\n", loglvl, str);
100}
101
102#ifndef CONFIG_ARM_UNWIND
103/*
104 * Stack pointers should always be within the kernels view of
105 * physical memory. If it is not there, then we can't dump
106 * out any information relating to the stack.
107 */
108static int verify_stack(unsigned long sp)
109{
110 if (sp < PAGE_OFFSET ||
111 (sp > (unsigned long)high_memory && high_memory != NULL))
112 return -EFAULT;
113
114 return 0;
115}
116#endif
117
118/*
119 * Dump out the contents of some memory nicely...
120 */
121static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
122 unsigned long top)
123{
124 unsigned long first;
125 mm_segment_t fs;
126 int i;
127
128 /*
129 * We need to switch to kernel mode so that we can use __get_user
130 * to safely read from kernel space. Note that we now dump the
131 * code first, just in case the backtrace kills us.
132 */
133 fs = get_fs();
134 set_fs(KERNEL_DS);
135
136 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top);
137
138 for (first = bottom & ~31; first < top; first += 32) {
139 unsigned long p;
140 char str[sizeof(" 12345678") * 8 + 1];
141
142 memset(str, ' ', sizeof(str));
143 str[sizeof(str) - 1] = '\0';
144
145 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
146 if (p >= bottom && p < top) {
147 unsigned long val;
148 if (__get_user(val, (unsigned long *)p) == 0)
149 sprintf(str + i * 9, " %08lx", val);
150 else
151 sprintf(str + i * 9, " ????????");
152 }
153 }
154 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
155 }
156
157 set_fs(fs);
158}
159
160static void __dump_instr(const char *lvl, struct pt_regs *regs)
161{
162 unsigned long addr = instruction_pointer(regs);
163 const int thumb = thumb_mode(regs);
164 const int width = thumb ? 4 : 8;
165 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
166 int i;
167
168 /*
169 * Note that we now dump the code first, just in case the backtrace
170 * kills us.
171 */
172
173 for (i = -4; i < 1 + !!thumb; i++) {
174 unsigned int val, bad;
175
176 if (thumb)
177 bad = get_user(val, &((u16 *)addr)[i]);
178 else
179 bad = get_user(val, &((u32 *)addr)[i]);
180
181 if (!bad)
182 p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ",
183 width, val);
184 else {
185 p += sprintf(p, "bad PC value");
186 break;
187 }
188 }
189 printk("%sCode: %s\n", lvl, str);
190}
191
192static void dump_instr(const char *lvl, struct pt_regs *regs)
193{
194 mm_segment_t fs;
195
196 if (!user_mode(regs)) {
197 fs = get_fs();
198 set_fs(KERNEL_DS);
199 __dump_instr(lvl, regs);
200 set_fs(fs);
201 } else {
202 __dump_instr(lvl, regs);
203 }
204}
205
206#ifdef CONFIG_ARM_UNWIND
207static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
208 const char *loglvl)
209{
210 unwind_backtrace(regs, tsk, loglvl);
211}
212#else
213static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
214 const char *loglvl)
215{
216 unsigned int fp, mode;
217 int ok = 1;
218
219 printk("%sBacktrace: ", loglvl);
220
221 if (!tsk)
222 tsk = current;
223
224 if (regs) {
225 fp = frame_pointer(regs);
226 mode = processor_mode(regs);
227 } else if (tsk != current) {
228 fp = thread_saved_fp(tsk);
229 mode = 0x10;
230 } else {
231 asm("mov %0, fp" : "=r" (fp) : : "cc");
232 mode = 0x10;
233 }
234
235 if (!fp) {
236 pr_cont("no frame pointer");
237 ok = 0;
238 } else if (verify_stack(fp)) {
239 pr_cont("invalid frame pointer 0x%08x", fp);
240 ok = 0;
241 } else if (fp < (unsigned long)end_of_stack(tsk))
242 pr_cont("frame pointer underflow");
243 pr_cont("\n");
244
245 if (ok)
246 c_backtrace(fp, mode, loglvl);
247}
248#endif
249
250void show_stack(struct task_struct *tsk, unsigned long *sp, const char *loglvl)
251{
252 dump_backtrace(NULL, tsk, loglvl);
253 barrier();
254}
255
256#ifdef CONFIG_PREEMPT
257#define S_PREEMPT " PREEMPT"
258#elif defined(CONFIG_PREEMPT_RT)
259#define S_PREEMPT " PREEMPT_RT"
260#else
261#define S_PREEMPT ""
262#endif
263#ifdef CONFIG_SMP
264#define S_SMP " SMP"
265#else
266#define S_SMP ""
267#endif
268#ifdef CONFIG_THUMB2_KERNEL
269#define S_ISA " THUMB2"
270#else
271#define S_ISA " ARM"
272#endif
273
274static int __die(const char *str, int err, struct pt_regs *regs)
275{
276 struct task_struct *tsk = current;
277 static int die_counter;
278 int ret;
279
280 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP S_ISA "\n",
281 str, err, ++die_counter);
282
283 /* trap and error numbers are mostly meaningless on ARM */
284 ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV);
285 if (ret == NOTIFY_STOP)
286 return 1;
287
288 print_modules();
289 __show_regs(regs);
290 __show_regs_alloc_free(regs);
291 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
292 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk));
293
294 if (!user_mode(regs) || in_interrupt()) {
295 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp,
296 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
297 dump_backtrace(regs, tsk, KERN_EMERG);
298 dump_instr(KERN_EMERG, regs);
299 }
300
301 return 0;
302}
303
304static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
305static int die_owner = -1;
306static unsigned int die_nest_count;
307
308static unsigned long oops_begin(void)
309{
310 int cpu;
311 unsigned long flags;
312
313 oops_enter();
314
315 /* racy, but better than risking deadlock. */
316 raw_local_irq_save(flags);
317 cpu = smp_processor_id();
318 if (!arch_spin_trylock(&die_lock)) {
319 if (cpu == die_owner)
320 /* nested oops. should stop eventually */;
321 else
322 arch_spin_lock(&die_lock);
323 }
324 die_nest_count++;
325 die_owner = cpu;
326 console_verbose();
327 bust_spinlocks(1);
328 return flags;
329}
330
331static void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
332{
333 if (regs && kexec_should_crash(current))
334 crash_kexec(regs);
335
336 bust_spinlocks(0);
337 die_owner = -1;
338 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
339 die_nest_count--;
340 if (!die_nest_count)
341 /* Nest count reaches zero, release the lock. */
342 arch_spin_unlock(&die_lock);
343 raw_local_irq_restore(flags);
344 oops_exit();
345
346 if (in_interrupt())
347 panic("Fatal exception in interrupt");
348 if (panic_on_oops)
349 panic("Fatal exception");
350 if (signr)
351 do_exit(signr);
352}
353
354/*
355 * This function is protected against re-entrancy.
356 */
357void die(const char *str, struct pt_regs *regs, int err)
358{
359 enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE;
360 unsigned long flags = oops_begin();
361 int sig = SIGSEGV;
362
363 if (!user_mode(regs))
364 bug_type = report_bug(regs->ARM_pc, regs);
365 if (bug_type != BUG_TRAP_TYPE_NONE)
366 str = "Oops - BUG";
367
368 if (__die(str, err, regs))
369 sig = 0;
370
371 oops_end(flags, regs, sig);
372}
373
374void arm_notify_die(const char *str, struct pt_regs *regs,
375 int signo, int si_code, void __user *addr,
376 unsigned long err, unsigned long trap)
377{
378 if (user_mode(regs)) {
379 current->thread.error_code = err;
380 current->thread.trap_no = trap;
381
382 force_sig_fault(signo, si_code, addr);
383 } else {
384 die(str, regs, err);
385 }
386}
387
388#ifdef CONFIG_GENERIC_BUG
389
390int is_valid_bugaddr(unsigned long pc)
391{
392#ifdef CONFIG_THUMB2_KERNEL
393 u16 bkpt;
394 u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE);
395#else
396 u32 bkpt;
397 u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE);
398#endif
399
400 if (get_kernel_nofault(bkpt, (void *)pc))
401 return 0;
402
403 return bkpt == insn;
404}
405
406#endif
407
408static LIST_HEAD(undef_hook);
409static DEFINE_RAW_SPINLOCK(undef_lock);
410
411void register_undef_hook(struct undef_hook *hook)
412{
413 unsigned long flags;
414
415 raw_spin_lock_irqsave(&undef_lock, flags);
416 list_add(&hook->node, &undef_hook);
417 raw_spin_unlock_irqrestore(&undef_lock, flags);
418}
419
420void unregister_undef_hook(struct undef_hook *hook)
421{
422 unsigned long flags;
423
424 raw_spin_lock_irqsave(&undef_lock, flags);
425 list_del(&hook->node);
426 raw_spin_unlock_irqrestore(&undef_lock, flags);
427}
428
429static nokprobe_inline
430int call_undef_hook(struct pt_regs *regs, unsigned int instr)
431{
432 struct undef_hook *hook;
433 unsigned long flags;
434 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL;
435
436 raw_spin_lock_irqsave(&undef_lock, flags);
437 list_for_each_entry(hook, &undef_hook, node)
438 if ((instr & hook->instr_mask) == hook->instr_val &&
439 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val)
440 fn = hook->fn;
441 raw_spin_unlock_irqrestore(&undef_lock, flags);
442
443 return fn ? fn(regs, instr) : 1;
444}
445
446asmlinkage void do_undefinstr(struct pt_regs *regs)
447{
448 unsigned int instr;
449 void __user *pc;
450
451 pc = (void __user *)instruction_pointer(regs);
452
453 if (processor_mode(regs) == SVC_MODE) {
454#ifdef CONFIG_THUMB2_KERNEL
455 if (thumb_mode(regs)) {
456 instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]);
457 if (is_wide_instruction(instr)) {
458 u16 inst2;
459 inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]);
460 instr = __opcode_thumb32_compose(instr, inst2);
461 }
462 } else
463#endif
464 instr = __mem_to_opcode_arm(*(u32 *) pc);
465 } else if (thumb_mode(regs)) {
466 if (get_user(instr, (u16 __user *)pc))
467 goto die_sig;
468 instr = __mem_to_opcode_thumb16(instr);
469 if (is_wide_instruction(instr)) {
470 unsigned int instr2;
471 if (get_user(instr2, (u16 __user *)pc+1))
472 goto die_sig;
473 instr2 = __mem_to_opcode_thumb16(instr2);
474 instr = __opcode_thumb32_compose(instr, instr2);
475 }
476 } else {
477 if (get_user(instr, (u32 __user *)pc))
478 goto die_sig;
479 instr = __mem_to_opcode_arm(instr);
480 }
481
482 if (call_undef_hook(regs, instr) == 0)
483 return;
484
485die_sig:
486#ifdef CONFIG_DEBUG_USER
487 if (user_debug & UDBG_UNDEFINED) {
488 pr_info("%s (%d): undefined instruction: pc=%p\n",
489 current->comm, task_pid_nr(current), pc);
490 __show_regs(regs);
491 dump_instr(KERN_INFO, regs);
492 }
493#endif
494 arm_notify_die("Oops - undefined instruction", regs,
495 SIGILL, ILL_ILLOPC, pc, 0, 6);
496}
497NOKPROBE_SYMBOL(do_undefinstr)
498
499/*
500 * Handle FIQ similarly to NMI on x86 systems.
501 *
502 * The runtime environment for NMIs is extremely restrictive
503 * (NMIs can pre-empt critical sections meaning almost all locking is
504 * forbidden) meaning this default FIQ handling must only be used in
505 * circumstances where non-maskability improves robustness, such as
506 * watchdog or debug logic.
507 *
508 * This handler is not appropriate for general purpose use in drivers
509 * platform code and can be overrideen using set_fiq_handler.
510 */
511asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs)
512{
513 struct pt_regs *old_regs = set_irq_regs(regs);
514
515 nmi_enter();
516
517 /* nop. FIQ handlers for special arch/arm features can be added here. */
518
519 nmi_exit();
520
521 set_irq_regs(old_regs);
522}
523
524/*
525 * bad_mode handles the impossible case in the vectors. If you see one of
526 * these, then it's extremely serious, and could mean you have buggy hardware.
527 * It never returns, and never tries to sync. We hope that we can at least
528 * dump out some state information...
529 */
530asmlinkage void bad_mode(struct pt_regs *regs, int reason)
531{
532 console_verbose();
533
534 pr_crit("Bad mode in %s handler detected\n", handler[reason]);
535
536 die("Oops - bad mode", regs, 0);
537 local_irq_disable();
538 panic("bad mode");
539}
540
541static int bad_syscall(int n, struct pt_regs *regs)
542{
543 if ((current->personality & PER_MASK) != PER_LINUX) {
544 send_sig(SIGSEGV, current, 1);
545 return regs->ARM_r0;
546 }
547
548#ifdef CONFIG_DEBUG_USER
549 if (user_debug & UDBG_SYSCALL) {
550 pr_err("[%d] %s: obsolete system call %08x.\n",
551 task_pid_nr(current), current->comm, n);
552 dump_instr(KERN_ERR, regs);
553 }
554#endif
555
556 arm_notify_die("Oops - bad syscall", regs, SIGILL, ILL_ILLTRP,
557 (void __user *)instruction_pointer(regs) -
558 (thumb_mode(regs) ? 2 : 4),
559 n, 0);
560
561 return regs->ARM_r0;
562}
563
564static inline int
565__do_cache_op(unsigned long start, unsigned long end)
566{
567 int ret;
568
569 do {
570 unsigned long chunk = min(PAGE_SIZE, end - start);
571
572 if (fatal_signal_pending(current))
573 return 0;
574
575 ret = flush_icache_user_range(start, start + chunk);
576 if (ret)
577 return ret;
578
579 cond_resched();
580 start += chunk;
581 } while (start < end);
582
583 return 0;
584}
585
586static inline int
587do_cache_op(unsigned long start, unsigned long end, int flags)
588{
589 if (end < start || flags)
590 return -EINVAL;
591
592 if (!access_ok(start, end - start))
593 return -EFAULT;
594
595 return __do_cache_op(start, end);
596}
597
598/*
599 * Handle all unrecognised system calls.
600 * 0x9f0000 - 0x9fffff are some more esoteric system calls
601 */
602#define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
603asmlinkage int arm_syscall(int no, struct pt_regs *regs)
604{
605 if ((no >> 16) != (__ARM_NR_BASE>> 16))
606 return bad_syscall(no, regs);
607
608 switch (no & 0xffff) {
609 case 0: /* branch through 0 */
610 arm_notify_die("branch through zero", regs,
611 SIGSEGV, SEGV_MAPERR, NULL, 0, 0);
612 return 0;
613
614 case NR(breakpoint): /* SWI BREAK_POINT */
615 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
616 ptrace_break(regs);
617 return regs->ARM_r0;
618
619 /*
620 * Flush a region from virtual address 'r0' to virtual address 'r1'
621 * _exclusive_. There is no alignment requirement on either address;
622 * user space does not need to know the hardware cache layout.
623 *
624 * r2 contains flags. It should ALWAYS be passed as ZERO until it
625 * is defined to be something else. For now we ignore it, but may
626 * the fires of hell burn in your belly if you break this rule. ;)
627 *
628 * (at a later date, we may want to allow this call to not flush
629 * various aspects of the cache. Passing '0' will guarantee that
630 * everything necessary gets flushed to maintain consistency in
631 * the specified region).
632 */
633 case NR(cacheflush):
634 return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
635
636 case NR(usr26):
637 if (!(elf_hwcap & HWCAP_26BIT))
638 break;
639 regs->ARM_cpsr &= ~MODE32_BIT;
640 return regs->ARM_r0;
641
642 case NR(usr32):
643 if (!(elf_hwcap & HWCAP_26BIT))
644 break;
645 regs->ARM_cpsr |= MODE32_BIT;
646 return regs->ARM_r0;
647
648 case NR(set_tls):
649 set_tls(regs->ARM_r0);
650 return 0;
651
652 case NR(get_tls):
653 return current_thread_info()->tp_value[0];
654
655 default:
656 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS
657 if not implemented, rather than raising SIGILL. This
658 way the calling program can gracefully determine whether
659 a feature is supported. */
660 if ((no & 0xffff) <= 0x7ff)
661 return -ENOSYS;
662 break;
663 }
664#ifdef CONFIG_DEBUG_USER
665 /*
666 * experience shows that these seem to indicate that
667 * something catastrophic has happened
668 */
669 if (user_debug & UDBG_SYSCALL) {
670 pr_err("[%d] %s: arm syscall %d\n",
671 task_pid_nr(current), current->comm, no);
672 dump_instr(KERN_ERR, regs);
673 if (user_mode(regs)) {
674 __show_regs(regs);
675 c_backtrace(frame_pointer(regs), processor_mode(regs), KERN_ERR);
676 }
677 }
678#endif
679 arm_notify_die("Oops - bad syscall(2)", regs, SIGILL, ILL_ILLTRP,
680 (void __user *)instruction_pointer(regs) -
681 (thumb_mode(regs) ? 2 : 4),
682 no, 0);
683 return 0;
684}
685
686#ifdef CONFIG_TLS_REG_EMUL
687
688/*
689 * We might be running on an ARMv6+ processor which should have the TLS
690 * register but for some reason we can't use it, or maybe an SMP system
691 * using a pre-ARMv6 processor (there are apparently a few prototypes like
692 * that in existence) and therefore access to that register must be
693 * emulated.
694 */
695
696static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
697{
698 int reg = (instr >> 12) & 15;
699 if (reg == 15)
700 return 1;
701 regs->uregs[reg] = current_thread_info()->tp_value[0];
702 regs->ARM_pc += 4;
703 return 0;
704}
705
706static struct undef_hook arm_mrc_hook = {
707 .instr_mask = 0x0fff0fff,
708 .instr_val = 0x0e1d0f70,
709 .cpsr_mask = PSR_T_BIT,
710 .cpsr_val = 0,
711 .fn = get_tp_trap,
712};
713
714static int __init arm_mrc_hook_init(void)
715{
716 register_undef_hook(&arm_mrc_hook);
717 return 0;
718}
719
720late_initcall(arm_mrc_hook_init);
721
722#endif
723
724/*
725 * A data abort trap was taken, but we did not handle the instruction.
726 * Try to abort the user program, or panic if it was the kernel.
727 */
728asmlinkage void
729baddataabort(int code, unsigned long instr, struct pt_regs *regs)
730{
731 unsigned long addr = instruction_pointer(regs);
732
733#ifdef CONFIG_DEBUG_USER
734 if (user_debug & UDBG_BADABORT) {
735 pr_err("8<--- cut here ---\n");
736 pr_err("[%d] %s: bad data abort: code %d instr 0x%08lx\n",
737 task_pid_nr(current), current->comm, code, instr);
738 dump_instr(KERN_ERR, regs);
739 show_pte(KERN_ERR, current->mm, addr);
740 }
741#endif
742
743 arm_notify_die("unknown data abort code", regs,
744 SIGILL, ILL_ILLOPC, (void __user *)addr, instr, 0);
745}
746
747void __readwrite_bug(const char *fn)
748{
749 pr_err("%s called, but not implemented\n", fn);
750 BUG();
751}
752EXPORT_SYMBOL(__readwrite_bug);
753
754void __pte_error(const char *file, int line, pte_t pte)
755{
756 pr_err("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte));
757}
758
759void __pmd_error(const char *file, int line, pmd_t pmd)
760{
761 pr_err("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd));
762}
763
764void __pgd_error(const char *file, int line, pgd_t pgd)
765{
766 pr_err("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd));
767}
768
769asmlinkage void __div0(void)
770{
771 pr_err("Division by zero in kernel.\n");
772 dump_stack();
773}
774EXPORT_SYMBOL(__div0);
775
776void abort(void)
777{
778 BUG();
779
780 /* if that doesn't kill us, halt */
781 panic("Oops failed to kill thread");
782}
783
784void __init trap_init(void)
785{
786 return;
787}
788
789#ifdef CONFIG_KUSER_HELPERS
790static void __init kuser_init(void *vectors)
791{
792 extern char __kuser_helper_start[], __kuser_helper_end[];
793 int kuser_sz = __kuser_helper_end - __kuser_helper_start;
794
795 memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
796
797 /*
798 * vectors + 0xfe0 = __kuser_get_tls
799 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8
800 */
801 if (tls_emu || has_tls_reg)
802 memcpy(vectors + 0xfe0, vectors + 0xfe8, 4);
803}
804#else
805static inline void __init kuser_init(void *vectors)
806{
807}
808#endif
809
810void __init early_trap_init(void *vectors_base)
811{
812#ifndef CONFIG_CPU_V7M
813 unsigned long vectors = (unsigned long)vectors_base;
814 extern char __stubs_start[], __stubs_end[];
815 extern char __vectors_start[], __vectors_end[];
816 unsigned i;
817
818 vectors_page = vectors_base;
819
820 /*
821 * Poison the vectors page with an undefined instruction. This
822 * instruction is chosen to be undefined for both ARM and Thumb
823 * ISAs. The Thumb version is an undefined instruction with a
824 * branch back to the undefined instruction.
825 */
826 for (i = 0; i < PAGE_SIZE / sizeof(u32); i++)
827 ((u32 *)vectors_base)[i] = 0xe7fddef1;
828
829 /*
830 * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
831 * into the vector page, mapped at 0xffff0000, and ensure these
832 * are visible to the instruction stream.
833 */
834 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
835 memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start);
836
837 kuser_init(vectors_base);
838
839 flush_icache_range(vectors, vectors + PAGE_SIZE * 2);
840#else /* ifndef CONFIG_CPU_V7M */
841 /*
842 * on V7-M there is no need to copy the vector table to a dedicated
843 * memory area. The address is configurable and so a table in the kernel
844 * image can be used.
845 */
846#endif
847}