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