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15#include <linux/signal.h>
16#include <linux/personality.h>
17#include <linux/kallsyms.h>
18#include <linux/spinlock.h>
19#include <linux/uaccess.h>
20#include <linux/hardirq.h>
21#include <linux/kdebug.h>
22#include <linux/kprobes.h>
23#include <linux/module.h>
24#include <linux/kexec.h>
25#include <linux/bug.h>
26#include <linux/delay.h>
27#include <linux/init.h>
28#include <linux/sched/signal.h>
29#include <linux/sched/debug.h>
30#include <linux/sched/task_stack.h>
31#include <linux/irq.h>
32
33#include <linux/atomic.h>
34#include <asm/cacheflush.h>
35#include <asm/exception.h>
36#include <asm/unistd.h>
37#include <asm/traps.h>
38#include <asm/ptrace.h>
39#include <asm/unwind.h>
40#include <asm/tls.h>
41#include <asm/system_misc.h>
42#include <asm/opcodes.h>
43
44
45static const char *handler[]= {
46 "prefetch abort",
47 "data abort",
48 "address exception",
49 "interrupt",
50 "undefined instruction",
51};
52
53void *vectors_page;
54
55#ifdef CONFIG_DEBUG_USER
56unsigned int user_debug;
57
58static int __init user_debug_setup(char *str)
59{
60 get_option(&str, &user_debug);
61 return 1;
62}
63__setup("user_debug=", user_debug_setup);
64#endif
65
66static void dump_mem(const char *, const char *, unsigned long, unsigned long);
67
68void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame)
69{
70#ifdef CONFIG_KALLSYMS
71 printk("[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from);
72#else
73 printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
74#endif
75
76 if (in_entry_text(from))
77 dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs));
78}
79
80void dump_backtrace_stm(u32 *stack, u32 instruction)
81{
82 char str[80], *p;
83 unsigned int x;
84 int reg;
85
86 for (reg = 10, x = 0, p = str; reg >= 0; reg--) {
87 if (instruction & BIT(reg)) {
88 p += sprintf(p, " r%d:%08x", reg, *stack--);
89 if (++x == 6) {
90 x = 0;
91 p = str;
92 printk("%s\n", str);
93 }
94 }
95 }
96 if (p != str)
97 printk("%s\n", str);
98}
99
100#ifndef CONFIG_ARM_UNWIND
101
102
103
104
105
106static int verify_stack(unsigned long sp)
107{
108 if (sp < PAGE_OFFSET ||
109 (sp > (unsigned long)high_memory && high_memory != NULL))
110 return -EFAULT;
111
112 return 0;
113}
114#endif
115
116
117
118
119static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
120 unsigned long top)
121{
122 unsigned long first;
123 mm_segment_t fs;
124 int i;
125
126
127
128
129
130
131 fs = get_fs();
132 set_fs(KERNEL_DS);
133
134 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top);
135
136 for (first = bottom & ~31; first < top; first += 32) {
137 unsigned long p;
138 char str[sizeof(" 12345678") * 8 + 1];
139
140 memset(str, ' ', sizeof(str));
141 str[sizeof(str) - 1] = '\0';
142
143 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
144 if (p >= bottom && p < top) {
145 unsigned long val;
146 if (__get_user(val, (unsigned long *)p) == 0)
147 sprintf(str + i * 9, " %08lx", val);
148 else
149 sprintf(str + i * 9, " ????????");
150 }
151 }
152 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
153 }
154
155 set_fs(fs);
156}
157
158static void __dump_instr(const char *lvl, struct pt_regs *regs)
159{
160 unsigned long addr = instruction_pointer(regs);
161 const int thumb = thumb_mode(regs);
162 const int width = thumb ? 4 : 8;
163 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
164 int i;
165
166
167
168
169
170
171 for (i = -4; i < 1 + !!thumb; i++) {
172 unsigned int val, bad;
173
174 if (thumb)
175 bad = get_user(val, &((u16 *)addr)[i]);
176 else
177 bad = get_user(val, &((u32 *)addr)[i]);
178
179 if (!bad)
180 p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ",
181 width, val);
182 else {
183 p += sprintf(p, "bad PC value");
184 break;
185 }
186 }
187 printk("%sCode: %s\n", lvl, str);
188}
189
190static void dump_instr(const char *lvl, struct pt_regs *regs)
191{
192 mm_segment_t fs;
193
194 if (!user_mode(regs)) {
195 fs = get_fs();
196 set_fs(KERNEL_DS);
197 __dump_instr(lvl, regs);
198 set_fs(fs);
199 } else {
200 __dump_instr(lvl, regs);
201 }
202}
203
204#ifdef CONFIG_ARM_UNWIND
205static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
206{
207 unwind_backtrace(regs, tsk);
208}
209#else
210static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
211{
212 unsigned int fp, mode;
213 int ok = 1;
214
215 printk("Backtrace: ");
216
217 if (!tsk)
218 tsk = current;
219
220 if (regs) {
221 fp = frame_pointer(regs);
222 mode = processor_mode(regs);
223 } else if (tsk != current) {
224 fp = thread_saved_fp(tsk);
225 mode = 0x10;
226 } else {
227 asm("mov %0, fp" : "=r" (fp) : : "cc");
228 mode = 0x10;
229 }
230
231 if (!fp) {
232 pr_cont("no frame pointer");
233 ok = 0;
234 } else if (verify_stack(fp)) {
235 pr_cont("invalid frame pointer 0x%08x", fp);
236 ok = 0;
237 } else if (fp < (unsigned long)end_of_stack(tsk))
238 pr_cont("frame pointer underflow");
239 pr_cont("\n");
240
241 if (ok)
242 c_backtrace(fp, mode);
243}
244#endif
245
246void show_stack(struct task_struct *tsk, unsigned long *sp)
247{
248 dump_backtrace(NULL, tsk);
249 barrier();
250}
251
252#ifdef CONFIG_PREEMPT
253#define S_PREEMPT " PREEMPT"
254#else
255#define S_PREEMPT ""
256#endif
257#ifdef CONFIG_SMP
258#define S_SMP " SMP"
259#else
260#define S_SMP ""
261#endif
262#ifdef CONFIG_THUMB2_KERNEL
263#define S_ISA " THUMB2"
264#else
265#define S_ISA " ARM"
266#endif
267
268static int __die(const char *str, int err, struct pt_regs *regs)
269{
270 struct task_struct *tsk = current;
271 static int die_counter;
272 int ret;
273
274 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP S_ISA "\n",
275 str, err, ++die_counter);
276
277
278 ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV);
279 if (ret == NOTIFY_STOP)
280 return 1;
281
282 print_modules();
283 __show_regs(regs);
284 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
285 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk));
286
287 if (!user_mode(regs) || in_interrupt()) {
288 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp,
289 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
290 dump_backtrace(regs, tsk);
291 dump_instr(KERN_EMERG, regs);
292 }
293
294 return 0;
295}
296
297static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
298static int die_owner = -1;
299static unsigned int die_nest_count;
300
301static unsigned long oops_begin(void)
302{
303 int cpu;
304 unsigned long flags;
305
306 oops_enter();
307
308
309 raw_local_irq_save(flags);
310 cpu = smp_processor_id();
311 if (!arch_spin_trylock(&die_lock)) {
312 if (cpu == die_owner)
313 ;
314 else
315 arch_spin_lock(&die_lock);
316 }
317 die_nest_count++;
318 die_owner = cpu;
319 console_verbose();
320 bust_spinlocks(1);
321 return flags;
322}
323
324static void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
325{
326 if (regs && kexec_should_crash(current))
327 crash_kexec(regs);
328
329 bust_spinlocks(0);
330 die_owner = -1;
331 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
332 die_nest_count--;
333 if (!die_nest_count)
334
335 arch_spin_unlock(&die_lock);
336 raw_local_irq_restore(flags);
337 oops_exit();
338
339 if (in_interrupt())
340 panic("Fatal exception in interrupt");
341 if (panic_on_oops)
342 panic("Fatal exception");
343 if (signr)
344 do_exit(signr);
345}
346
347
348
349
350void die(const char *str, struct pt_regs *regs, int err)
351{
352 enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE;
353 unsigned long flags = oops_begin();
354 int sig = SIGSEGV;
355
356 if (!user_mode(regs))
357 bug_type = report_bug(regs->ARM_pc, regs);
358 if (bug_type != BUG_TRAP_TYPE_NONE)
359 str = "Oops - BUG";
360
361 if (__die(str, err, regs))
362 sig = 0;
363
364 oops_end(flags, regs, sig);
365}
366
367void arm_notify_die(const char *str, struct pt_regs *regs,
368 int signo, int si_code, void __user *addr,
369 unsigned long err, unsigned long trap)
370{
371 if (user_mode(regs)) {
372 current->thread.error_code = err;
373 current->thread.trap_no = trap;
374
375 force_sig_fault(signo, si_code, addr, current);
376 } else {
377 die(str, regs, err);
378 }
379}
380
381#ifdef CONFIG_GENERIC_BUG
382
383int is_valid_bugaddr(unsigned long pc)
384{
385#ifdef CONFIG_THUMB2_KERNEL
386 u16 bkpt;
387 u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE);
388#else
389 u32 bkpt;
390 u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE);
391#endif
392
393 if (probe_kernel_address((unsigned *)pc, bkpt))
394 return 0;
395
396 return bkpt == insn;
397}
398
399#endif
400
401static LIST_HEAD(undef_hook);
402static DEFINE_RAW_SPINLOCK(undef_lock);
403
404void register_undef_hook(struct undef_hook *hook)
405{
406 unsigned long flags;
407
408 raw_spin_lock_irqsave(&undef_lock, flags);
409 list_add(&hook->node, &undef_hook);
410 raw_spin_unlock_irqrestore(&undef_lock, flags);
411}
412
413void unregister_undef_hook(struct undef_hook *hook)
414{
415 unsigned long flags;
416
417 raw_spin_lock_irqsave(&undef_lock, flags);
418 list_del(&hook->node);
419 raw_spin_unlock_irqrestore(&undef_lock, flags);
420}
421
422static nokprobe_inline
423int call_undef_hook(struct pt_regs *regs, unsigned int instr)
424{
425 struct undef_hook *hook;
426 unsigned long flags;
427 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL;
428
429 raw_spin_lock_irqsave(&undef_lock, flags);
430 list_for_each_entry(hook, &undef_hook, node)
431 if ((instr & hook->instr_mask) == hook->instr_val &&
432 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val)
433 fn = hook->fn;
434 raw_spin_unlock_irqrestore(&undef_lock, flags);
435
436 return fn ? fn(regs, instr) : 1;
437}
438
439asmlinkage void do_undefinstr(struct pt_regs *regs)
440{
441 unsigned int instr;
442 void __user *pc;
443
444 pc = (void __user *)instruction_pointer(regs);
445
446 if (processor_mode(regs) == SVC_MODE) {
447#ifdef CONFIG_THUMB2_KERNEL
448 if (thumb_mode(regs)) {
449 instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]);
450 if (is_wide_instruction(instr)) {
451 u16 inst2;
452 inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]);
453 instr = __opcode_thumb32_compose(instr, inst2);
454 }
455 } else
456#endif
457 instr = __mem_to_opcode_arm(*(u32 *) pc);
458 } else if (thumb_mode(regs)) {
459 if (get_user(instr, (u16 __user *)pc))
460 goto die_sig;
461 instr = __mem_to_opcode_thumb16(instr);
462 if (is_wide_instruction(instr)) {
463 unsigned int instr2;
464 if (get_user(instr2, (u16 __user *)pc+1))
465 goto die_sig;
466 instr2 = __mem_to_opcode_thumb16(instr2);
467 instr = __opcode_thumb32_compose(instr, instr2);
468 }
469 } else {
470 if (get_user(instr, (u32 __user *)pc))
471 goto die_sig;
472 instr = __mem_to_opcode_arm(instr);
473 }
474
475 if (call_undef_hook(regs, instr) == 0)
476 return;
477
478die_sig:
479#ifdef CONFIG_DEBUG_USER
480 if (user_debug & UDBG_UNDEFINED) {
481 pr_info("%s (%d): undefined instruction: pc=%p\n",
482 current->comm, task_pid_nr(current), pc);
483 __show_regs(regs);
484 dump_instr(KERN_INFO, regs);
485 }
486#endif
487 arm_notify_die("Oops - undefined instruction", regs,
488 SIGILL, ILL_ILLOPC, pc, 0, 6);
489}
490NOKPROBE_SYMBOL(do_undefinstr)
491
492
493
494
495
496
497
498
499
500
501
502
503
504asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs)
505{
506 struct pt_regs *old_regs = set_irq_regs(regs);
507
508 nmi_enter();
509
510
511
512 nmi_exit();
513
514 set_irq_regs(old_regs);
515}
516
517
518
519
520
521
522
523asmlinkage void bad_mode(struct pt_regs *regs, int reason)
524{
525 console_verbose();
526
527 pr_crit("Bad mode in %s handler detected\n", handler[reason]);
528
529 die("Oops - bad mode", regs, 0);
530 local_irq_disable();
531 panic("bad mode");
532}
533
534static int bad_syscall(int n, struct pt_regs *regs)
535{
536 if ((current->personality & PER_MASK) != PER_LINUX) {
537 send_sig(SIGSEGV, current, 1);
538 return regs->ARM_r0;
539 }
540
541#ifdef CONFIG_DEBUG_USER
542 if (user_debug & UDBG_SYSCALL) {
543 pr_err("[%d] %s: obsolete system call %08x.\n",
544 task_pid_nr(current), current->comm, n);
545 dump_instr(KERN_ERR, regs);
546 }
547#endif
548
549 arm_notify_die("Oops - bad syscall", regs, SIGILL, ILL_ILLTRP,
550 (void __user *)instruction_pointer(regs) -
551 (thumb_mode(regs) ? 2 : 4),
552 n, 0);
553
554 return regs->ARM_r0;
555}
556
557static inline int
558__do_cache_op(unsigned long start, unsigned long end)
559{
560 int ret;
561
562 do {
563 unsigned long chunk = min(PAGE_SIZE, end - start);
564
565 if (fatal_signal_pending(current))
566 return 0;
567
568 ret = flush_cache_user_range(start, start + chunk);
569 if (ret)
570 return ret;
571
572 cond_resched();
573 start += chunk;
574 } while (start < end);
575
576 return 0;
577}
578
579static inline int
580do_cache_op(unsigned long start, unsigned long end, int flags)
581{
582 if (end < start || flags)
583 return -EINVAL;
584
585 if (!access_ok(start, end - start))
586 return -EFAULT;
587
588 return __do_cache_op(start, end);
589}
590
591
592
593
594
595#define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
596asmlinkage int arm_syscall(int no, struct pt_regs *regs)
597{
598 if ((no >> 16) != (__ARM_NR_BASE>> 16))
599 return bad_syscall(no, regs);
600
601 switch (no & 0xffff) {
602 case 0:
603 arm_notify_die("branch through zero", regs,
604 SIGSEGV, SEGV_MAPERR, NULL, 0, 0);
605 return 0;
606
607 case NR(breakpoint):
608 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
609 ptrace_break(current, regs);
610 return regs->ARM_r0;
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626 case NR(cacheflush):
627 return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
628
629 case NR(usr26):
630 if (!(elf_hwcap & HWCAP_26BIT))
631 break;
632 regs->ARM_cpsr &= ~MODE32_BIT;
633 return regs->ARM_r0;
634
635 case NR(usr32):
636 if (!(elf_hwcap & HWCAP_26BIT))
637 break;
638 regs->ARM_cpsr |= MODE32_BIT;
639 return regs->ARM_r0;
640
641 case NR(set_tls):
642 set_tls(regs->ARM_r0);
643 return 0;
644
645 case NR(get_tls):
646 return current_thread_info()->tp_value[0];
647
648 default:
649
650
651
652
653 if ((no & 0xffff) <= 0x7ff)
654 return -ENOSYS;
655 break;
656 }
657#ifdef CONFIG_DEBUG_USER
658
659
660
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 arm_notify_die("Oops - bad syscall(2)", regs, SIGILL, ILL_ILLTRP,
673 (void __user *)instruction_pointer(regs) -
674 (thumb_mode(regs) ? 2 : 4),
675 no, 0);
676 return 0;
677}
678
679#ifdef CONFIG_TLS_REG_EMUL
680
681
682
683
684
685
686
687
688
689static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
690{
691 int reg = (instr >> 12) & 15;
692 if (reg == 15)
693 return 1;
694 regs->uregs[reg] = current_thread_info()->tp_value[0];
695 regs->ARM_pc += 4;
696 return 0;
697}
698
699static struct undef_hook arm_mrc_hook = {
700 .instr_mask = 0x0fff0fff,
701 .instr_val = 0x0e1d0f70,
702 .cpsr_mask = PSR_T_BIT,
703 .cpsr_val = 0,
704 .fn = get_tp_trap,
705};
706
707static int __init arm_mrc_hook_init(void)
708{
709 register_undef_hook(&arm_mrc_hook);
710 return 0;
711}
712
713late_initcall(arm_mrc_hook_init);
714
715#endif
716
717
718
719
720
721asmlinkage void
722baddataabort(int code, unsigned long instr, struct pt_regs *regs)
723{
724 unsigned long addr = instruction_pointer(regs);
725
726#ifdef CONFIG_DEBUG_USER
727 if (user_debug & UDBG_BADABORT) {
728 pr_err("[%d] %s: bad data abort: code %d instr 0x%08lx\n",
729 task_pid_nr(current), current->comm, code, instr);
730 dump_instr(KERN_ERR, regs);
731 show_pte(current->mm, addr);
732 }
733#endif
734
735 arm_notify_die("unknown data abort code", regs,
736 SIGILL, ILL_ILLOPC, (void __user *)addr, instr, 0);
737}
738
739void __readwrite_bug(const char *fn)
740{
741 pr_err("%s called, but not implemented\n", fn);
742 BUG();
743}
744EXPORT_SYMBOL(__readwrite_bug);
745
746void __pte_error(const char *file, int line, pte_t pte)
747{
748 pr_err("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte));
749}
750
751void __pmd_error(const char *file, int line, pmd_t pmd)
752{
753 pr_err("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd));
754}
755
756void __pgd_error(const char *file, int line, pgd_t pgd)
757{
758 pr_err("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd));
759}
760
761asmlinkage void __div0(void)
762{
763 pr_err("Division by zero in kernel.\n");
764 dump_stack();
765}
766EXPORT_SYMBOL(__div0);
767
768void abort(void)
769{
770 BUG();
771
772
773 panic("Oops failed to kill thread");
774}
775
776void __init trap_init(void)
777{
778 return;
779}
780
781#ifdef CONFIG_KUSER_HELPERS
782static void __init kuser_init(void *vectors)
783{
784 extern char __kuser_helper_start[], __kuser_helper_end[];
785 int kuser_sz = __kuser_helper_end - __kuser_helper_start;
786
787 memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
788
789
790
791
792
793 if (tls_emu || has_tls_reg)
794 memcpy(vectors + 0xfe0, vectors + 0xfe8, 4);
795}
796#else
797static inline void __init kuser_init(void *vectors)
798{
799}
800#endif
801
802void __init early_trap_init(void *vectors_base)
803{
804#ifndef CONFIG_CPU_V7M
805 unsigned long vectors = (unsigned long)vectors_base;
806 extern char __stubs_start[], __stubs_end[];
807 extern char __vectors_start[], __vectors_end[];
808 unsigned i;
809
810 vectors_page = vectors_base;
811
812
813
814
815
816
817
818 for (i = 0; i < PAGE_SIZE / sizeof(u32); i++)
819 ((u32 *)vectors_base)[i] = 0xe7fddef1;
820
821
822
823
824
825
826 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
827 memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start);
828
829 kuser_init(vectors_base);
830
831 flush_icache_range(vectors, vectors + PAGE_SIZE * 2);
832#else
833
834
835
836
837
838#endif
839}
840