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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
105
106
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
120
121static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
122 unsigned long top)
123{
124 unsigned long first;
125 int i;
126
127 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top);
128
129 for (first = bottom & ~31; first < top; first += 32) {
130 unsigned long p;
131 char str[sizeof(" 12345678") * 8 + 1];
132
133 memset(str, ' ', sizeof(str));
134 str[sizeof(str) - 1] = '\0';
135
136 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
137 if (p >= bottom && p < top) {
138 unsigned long val;
139 if (!get_kernel_nofault(val, (unsigned long *)p))
140 sprintf(str + i * 9, " %08lx", val);
141 else
142 sprintf(str + i * 9, " ????????");
143 }
144 }
145 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
146 }
147}
148
149static void dump_instr(const char *lvl, struct pt_regs *regs)
150{
151 unsigned long addr = instruction_pointer(regs);
152 const int thumb = thumb_mode(regs);
153 const int width = thumb ? 4 : 8;
154 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
155 int i;
156
157
158
159
160
161
162 for (i = -4; i < 1 + !!thumb; i++) {
163 unsigned int val, bad;
164
165 if (!user_mode(regs)) {
166 if (thumb) {
167 u16 val16;
168 bad = get_kernel_nofault(val16, &((u16 *)addr)[i]);
169 val = val16;
170 } else {
171 bad = get_kernel_nofault(val, &((u32 *)addr)[i]);
172 }
173 } else {
174 if (thumb)
175 bad = get_user(val, &((u16 *)addr)[i]);
176 else
177 bad = get_user(val, &((u32 *)addr)[i]);
178 }
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
191#ifdef CONFIG_ARM_UNWIND
192static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
193 const char *loglvl)
194{
195 unwind_backtrace(regs, tsk, loglvl);
196}
197#else
198static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
199 const char *loglvl)
200{
201 unsigned int fp, mode;
202 int ok = 1;
203
204 printk("%sBacktrace: ", loglvl);
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, loglvl);
232}
233#endif
234
235void show_stack(struct task_struct *tsk, unsigned long *sp, const char *loglvl)
236{
237 dump_backtrace(NULL, tsk, loglvl);
238 barrier();
239}
240
241#ifdef CONFIG_PREEMPT
242#define S_PREEMPT " PREEMPT"
243#elif defined(CONFIG_PREEMPT_RT)
244#define S_PREEMPT " PREEMPT_RT"
245#else
246#define S_PREEMPT ""
247#endif
248#ifdef CONFIG_SMP
249#define S_SMP " SMP"
250#else
251#define S_SMP ""
252#endif
253#ifdef CONFIG_THUMB2_KERNEL
254#define S_ISA " THUMB2"
255#else
256#define S_ISA " ARM"
257#endif
258
259static int __die(const char *str, int err, struct pt_regs *regs)
260{
261 struct task_struct *tsk = current;
262 static int die_counter;
263 int ret;
264
265 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP S_ISA "\n",
266 str, err, ++die_counter);
267
268
269 ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV);
270 if (ret == NOTIFY_STOP)
271 return 1;
272
273 print_modules();
274 __show_regs(regs);
275 __show_regs_alloc_free(regs);
276 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
277 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk));
278
279 if (!user_mode(regs) || in_interrupt()) {
280 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp,
281 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
282 dump_backtrace(regs, tsk, KERN_EMERG);
283 dump_instr(KERN_EMERG, regs);
284 }
285
286 return 0;
287}
288
289static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
290static int die_owner = -1;
291static unsigned int die_nest_count;
292
293static unsigned long oops_begin(void)
294{
295 int cpu;
296 unsigned long flags;
297
298 oops_enter();
299
300
301 raw_local_irq_save(flags);
302 cpu = smp_processor_id();
303 if (!arch_spin_trylock(&die_lock)) {
304 if (cpu == die_owner)
305 ;
306 else
307 arch_spin_lock(&die_lock);
308 }
309 die_nest_count++;
310 die_owner = cpu;
311 console_verbose();
312 bust_spinlocks(1);
313 return flags;
314}
315
316static void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
317{
318 if (regs && kexec_should_crash(current))
319 crash_kexec(regs);
320
321 bust_spinlocks(0);
322 die_owner = -1;
323 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
324 die_nest_count--;
325 if (!die_nest_count)
326
327 arch_spin_unlock(&die_lock);
328 raw_local_irq_restore(flags);
329 oops_exit();
330
331 if (in_interrupt())
332 panic("Fatal exception in interrupt");
333 if (panic_on_oops)
334 panic("Fatal exception");
335 if (signr)
336 do_exit(signr);
337}
338
339
340
341
342void die(const char *str, struct pt_regs *regs, int err)
343{
344 enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE;
345 unsigned long flags = oops_begin();
346 int sig = SIGSEGV;
347
348 if (!user_mode(regs))
349 bug_type = report_bug(regs->ARM_pc, regs);
350 if (bug_type != BUG_TRAP_TYPE_NONE)
351 str = "Oops - BUG";
352
353 if (__die(str, err, regs))
354 sig = 0;
355
356 oops_end(flags, regs, sig);
357}
358
359void arm_notify_die(const char *str, struct pt_regs *regs,
360 int signo, int si_code, void __user *addr,
361 unsigned long err, unsigned long trap)
362{
363 if (user_mode(regs)) {
364 current->thread.error_code = err;
365 current->thread.trap_no = trap;
366
367 force_sig_fault(signo, si_code, addr);
368 } else {
369 die(str, regs, err);
370 }
371}
372
373#ifdef CONFIG_GENERIC_BUG
374
375int is_valid_bugaddr(unsigned long pc)
376{
377#ifdef CONFIG_THUMB2_KERNEL
378 u16 bkpt;
379 u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE);
380#else
381 u32 bkpt;
382 u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE);
383#endif
384
385 if (get_kernel_nofault(bkpt, (void *)pc))
386 return 0;
387
388 return bkpt == insn;
389}
390
391#endif
392
393static LIST_HEAD(undef_hook);
394static DEFINE_RAW_SPINLOCK(undef_lock);
395
396void register_undef_hook(struct undef_hook *hook)
397{
398 unsigned long flags;
399
400 raw_spin_lock_irqsave(&undef_lock, flags);
401 list_add(&hook->node, &undef_hook);
402 raw_spin_unlock_irqrestore(&undef_lock, flags);
403}
404
405void unregister_undef_hook(struct undef_hook *hook)
406{
407 unsigned long flags;
408
409 raw_spin_lock_irqsave(&undef_lock, flags);
410 list_del(&hook->node);
411 raw_spin_unlock_irqrestore(&undef_lock, flags);
412}
413
414static nokprobe_inline
415int call_undef_hook(struct pt_regs *regs, unsigned int instr)
416{
417 struct undef_hook *hook;
418 unsigned long flags;
419 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL;
420
421 raw_spin_lock_irqsave(&undef_lock, flags);
422 list_for_each_entry(hook, &undef_hook, node)
423 if ((instr & hook->instr_mask) == hook->instr_val &&
424 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val)
425 fn = hook->fn;
426 raw_spin_unlock_irqrestore(&undef_lock, flags);
427
428 return fn ? fn(regs, instr) : 1;
429}
430
431asmlinkage void do_undefinstr(struct pt_regs *regs)
432{
433 unsigned int instr;
434 void __user *pc;
435
436 pc = (void __user *)instruction_pointer(regs);
437
438 if (processor_mode(regs) == SVC_MODE) {
439#ifdef CONFIG_THUMB2_KERNEL
440 if (thumb_mode(regs)) {
441 instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]);
442 if (is_wide_instruction(instr)) {
443 u16 inst2;
444 inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]);
445 instr = __opcode_thumb32_compose(instr, inst2);
446 }
447 } else
448#endif
449 instr = __mem_to_opcode_arm(*(u32 *) pc);
450 } else if (thumb_mode(regs)) {
451 if (get_user(instr, (u16 __user *)pc))
452 goto die_sig;
453 instr = __mem_to_opcode_thumb16(instr);
454 if (is_wide_instruction(instr)) {
455 unsigned int instr2;
456 if (get_user(instr2, (u16 __user *)pc+1))
457 goto die_sig;
458 instr2 = __mem_to_opcode_thumb16(instr2);
459 instr = __opcode_thumb32_compose(instr, instr2);
460 }
461 } else {
462 if (get_user(instr, (u32 __user *)pc))
463 goto die_sig;
464 instr = __mem_to_opcode_arm(instr);
465 }
466
467 if (call_undef_hook(regs, instr) == 0)
468 return;
469
470die_sig:
471#ifdef CONFIG_DEBUG_USER
472 if (user_debug & UDBG_UNDEFINED) {
473 pr_info("%s (%d): undefined instruction: pc=%p\n",
474 current->comm, task_pid_nr(current), pc);
475 __show_regs(regs);
476 dump_instr(KERN_INFO, regs);
477 }
478#endif
479 arm_notify_die("Oops - undefined instruction", regs,
480 SIGILL, ILL_ILLOPC, pc, 0, 6);
481}
482NOKPROBE_SYMBOL(do_undefinstr)
483
484
485
486
487
488
489
490
491
492
493
494
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
503
504 nmi_exit();
505
506 set_irq_regs(old_regs);
507}
508
509
510
511
512
513
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 if ((current->personality & PER_MASK) != PER_LINUX) {
529 send_sig(SIGSEGV, current, 1);
530 return regs->ARM_r0;
531 }
532
533#ifdef CONFIG_DEBUG_USER
534 if (user_debug & UDBG_SYSCALL) {
535 pr_err("[%d] %s: obsolete system call %08x.\n",
536 task_pid_nr(current), current->comm, n);
537 dump_instr(KERN_ERR, regs);
538 }
539#endif
540
541 arm_notify_die("Oops - bad syscall", regs, SIGILL, ILL_ILLTRP,
542 (void __user *)instruction_pointer(regs) -
543 (thumb_mode(regs) ? 2 : 4),
544 n, 0);
545
546 return regs->ARM_r0;
547}
548
549static inline int
550__do_cache_op(unsigned long start, unsigned long end)
551{
552 int ret;
553
554 do {
555 unsigned long chunk = min(PAGE_SIZE, end - start);
556
557 if (fatal_signal_pending(current))
558 return 0;
559
560 ret = flush_icache_user_range(start, start + chunk);
561 if (ret)
562 return ret;
563
564 cond_resched();
565 start += chunk;
566 } while (start < end);
567
568 return 0;
569}
570
571static inline int
572do_cache_op(unsigned long start, unsigned long end, int flags)
573{
574 if (end < start || flags)
575 return -EINVAL;
576
577 if (!access_ok(start, end - start))
578 return -EFAULT;
579
580 return __do_cache_op(start, end);
581}
582
583
584
585
586
587#define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
588asmlinkage int arm_syscall(int no, struct pt_regs *regs)
589{
590 if ((no >> 16) != (__ARM_NR_BASE>> 16))
591 return bad_syscall(no, regs);
592
593 switch (no & 0xffff) {
594 case 0:
595 arm_notify_die("branch through zero", regs,
596 SIGSEGV, SEGV_MAPERR, NULL, 0, 0);
597 return 0;
598
599 case NR(breakpoint):
600 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
601 ptrace_break(regs);
602 return regs->ARM_r0;
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618 case NR(cacheflush):
619 return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
620
621 case NR(usr26):
622 if (!(elf_hwcap & HWCAP_26BIT))
623 break;
624 regs->ARM_cpsr &= ~MODE32_BIT;
625 return regs->ARM_r0;
626
627 case NR(usr32):
628 if (!(elf_hwcap & HWCAP_26BIT))
629 break;
630 regs->ARM_cpsr |= MODE32_BIT;
631 return regs->ARM_r0;
632
633 case NR(set_tls):
634 set_tls(regs->ARM_r0);
635 return 0;
636
637 case NR(get_tls):
638 return current_thread_info()->tp_value[0];
639
640 default:
641
642
643
644
645 if ((no & 0xffff) <= 0x7ff)
646 return -ENOSYS;
647 break;
648 }
649#ifdef CONFIG_DEBUG_USER
650
651
652
653
654 if (user_debug & UDBG_SYSCALL) {
655 pr_err("[%d] %s: arm syscall %d\n",
656 task_pid_nr(current), current->comm, no);
657 dump_instr(KERN_ERR, regs);
658 if (user_mode(regs)) {
659 __show_regs(regs);
660 c_backtrace(frame_pointer(regs), processor_mode(regs), KERN_ERR);
661 }
662 }
663#endif
664 arm_notify_die("Oops - bad syscall(2)", regs, SIGILL, ILL_ILLTRP,
665 (void __user *)instruction_pointer(regs) -
666 (thumb_mode(regs) ? 2 : 4),
667 no, 0);
668 return 0;
669}
670
671#ifdef CONFIG_TLS_REG_EMUL
672
673
674
675
676
677
678
679
680
681static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
682{
683 int reg = (instr >> 12) & 15;
684 if (reg == 15)
685 return 1;
686 regs->uregs[reg] = current_thread_info()->tp_value[0];
687 regs->ARM_pc += 4;
688 return 0;
689}
690
691static struct undef_hook arm_mrc_hook = {
692 .instr_mask = 0x0fff0fff,
693 .instr_val = 0x0e1d0f70,
694 .cpsr_mask = PSR_T_BIT,
695 .cpsr_val = 0,
696 .fn = get_tp_trap,
697};
698
699static int __init arm_mrc_hook_init(void)
700{
701 register_undef_hook(&arm_mrc_hook);
702 return 0;
703}
704
705late_initcall(arm_mrc_hook_init);
706
707#endif
708
709
710
711
712
713asmlinkage void
714baddataabort(int code, unsigned long instr, struct pt_regs *regs)
715{
716 unsigned long addr = instruction_pointer(regs);
717
718#ifdef CONFIG_DEBUG_USER
719 if (user_debug & UDBG_BADABORT) {
720 pr_err("8<--- cut here ---\n");
721 pr_err("[%d] %s: bad data abort: code %d instr 0x%08lx\n",
722 task_pid_nr(current), current->comm, code, instr);
723 dump_instr(KERN_ERR, regs);
724 show_pte(KERN_ERR, current->mm, addr);
725 }
726#endif
727
728 arm_notify_die("unknown data abort code", regs,
729 SIGILL, ILL_ILLOPC, (void __user *)addr, instr, 0);
730}
731
732void __readwrite_bug(const char *fn)
733{
734 pr_err("%s called, but not implemented\n", fn);
735 BUG();
736}
737EXPORT_SYMBOL(__readwrite_bug);
738
739void __pte_error(const char *file, int line, pte_t pte)
740{
741 pr_err("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte));
742}
743
744void __pmd_error(const char *file, int line, pmd_t pmd)
745{
746 pr_err("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd));
747}
748
749void __pgd_error(const char *file, int line, pgd_t pgd)
750{
751 pr_err("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd));
752}
753
754asmlinkage void __div0(void)
755{
756 pr_err("Division by zero in kernel.\n");
757 dump_stack();
758}
759EXPORT_SYMBOL(__div0);
760
761void abort(void)
762{
763 BUG();
764
765
766 panic("Oops failed to kill thread");
767}
768
769#ifdef CONFIG_KUSER_HELPERS
770static void __init kuser_init(void *vectors)
771{
772 extern char __kuser_helper_start[], __kuser_helper_end[];
773 int kuser_sz = __kuser_helper_end - __kuser_helper_start;
774
775 memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
776
777
778
779
780
781 if (tls_emu || has_tls_reg)
782 memcpy(vectors + 0xfe0, vectors + 0xfe8, 4);
783}
784#else
785static inline void __init kuser_init(void *vectors)
786{
787}
788#endif
789
790void __init early_trap_init(void *vectors_base)
791{
792#ifndef CONFIG_CPU_V7M
793 unsigned long vectors = (unsigned long)vectors_base;
794 extern char __stubs_start[], __stubs_end[];
795 extern char __vectors_start[], __vectors_end[];
796 unsigned i;
797
798 vectors_page = vectors_base;
799
800
801
802
803
804
805
806 for (i = 0; i < PAGE_SIZE / sizeof(u32); i++)
807 ((u32 *)vectors_base)[i] = 0xe7fddef1;
808
809
810
811
812
813
814 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
815 memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start);
816
817 kuser_init(vectors_base);
818
819 flush_icache_range(vectors, vectors + PAGE_SIZE * 2);
820#else
821
822
823
824
825
826#endif
827}
828