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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/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/signal.h>
28#include <linux/sched/debug.h>
29#include <linux/sched/task_stack.h>
30#include <linux/irq.h>
31
32#include <linux/atomic.h>
33#include <asm/cacheflush.h>
34#include <asm/exception.h>
35#include <asm/unistd.h>
36#include <asm/traps.h>
37#include <asm/ptrace.h>
38#include <asm/unwind.h>
39#include <asm/tls.h>
40#include <asm/system_misc.h>
41#include <asm/opcodes.h>
42
43
44static const char *handler[]= {
45 "prefetch abort",
46 "data abort",
47 "address exception",
48 "interrupt",
49 "undefined instruction",
50};
51
52void *vectors_page;
53
54#ifdef CONFIG_DEBUG_USER
55unsigned int user_debug;
56
57static int __init user_debug_setup(char *str)
58{
59 get_option(&str, &user_debug);
60 return 1;
61}
62__setup("user_debug=", user_debug_setup);
63#endif
64
65static void dump_mem(const char *, const char *, unsigned long, unsigned long);
66
67void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame)
68{
69#ifdef CONFIG_KALLSYMS
70 printk("[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from);
71#else
72 printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
73#endif
74
75 if (in_exception_text(where))
76 dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs));
77}
78
79void dump_backtrace_stm(u32 *stack, u32 instruction)
80{
81 char str[80], *p;
82 unsigned int x;
83 int reg;
84
85 for (reg = 10, x = 0, p = str; reg >= 0; reg--) {
86 if (instruction & BIT(reg)) {
87 p += sprintf(p, " r%d:%08x", reg, *stack--);
88 if (++x == 6) {
89 x = 0;
90 p = str;
91 printk("%s\n", str);
92 }
93 }
94 }
95 if (p != str)
96 printk("%s\n", str);
97}
98
99#ifndef CONFIG_ARM_UNWIND
100
101
102
103
104
105static int verify_stack(unsigned long sp)
106{
107 if (sp < PAGE_OFFSET ||
108 (sp > (unsigned long)high_memory && high_memory != NULL))
109 return -EFAULT;
110
111 return 0;
112}
113#endif
114
115
116
117
118static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
119 unsigned long top)
120{
121 unsigned long first;
122 mm_segment_t fs;
123 int i;
124
125
126
127
128
129
130 fs = get_fs();
131 set_fs(KERNEL_DS);
132
133 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top);
134
135 for (first = bottom & ~31; first < top; first += 32) {
136 unsigned long p;
137 char str[sizeof(" 12345678") * 8 + 1];
138
139 memset(str, ' ', sizeof(str));
140 str[sizeof(str) - 1] = '\0';
141
142 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
143 if (p >= bottom && p < top) {
144 unsigned long val;
145 if (__get_user(val, (unsigned long *)p) == 0)
146 sprintf(str + i * 9, " %08lx", val);
147 else
148 sprintf(str + i * 9, " ????????");
149 }
150 }
151 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
152 }
153
154 set_fs(fs);
155}
156
157static void __dump_instr(const char *lvl, struct pt_regs *regs)
158{
159 unsigned long addr = instruction_pointer(regs);
160 const int thumb = thumb_mode(regs);
161 const int width = thumb ? 4 : 8;
162 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
163 int i;
164
165
166
167
168
169
170 for (i = -4; i < 1 + !!thumb; i++) {
171 unsigned int val, bad;
172
173 if (thumb)
174 bad = get_user(val, &((u16 *)addr)[i]);
175 else
176 bad = get_user(val, &((u32 *)addr)[i]);
177
178 if (!bad)
179 p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ",
180 width, val);
181 else {
182 p += sprintf(p, "bad PC value");
183 break;
184 }
185 }
186 printk("%sCode: %s\n", lvl, str);
187}
188
189static void dump_instr(const char *lvl, struct pt_regs *regs)
190{
191 mm_segment_t fs;
192
193 if (!user_mode(regs)) {
194 fs = get_fs();
195 set_fs(KERNEL_DS);
196 __dump_instr(lvl, regs);
197 set_fs(fs);
198 } else {
199 __dump_instr(lvl, regs);
200 }
201}
202
203#ifdef CONFIG_ARM_UNWIND
204static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
205{
206 unwind_backtrace(regs, tsk);
207}
208#else
209static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
210{
211 unsigned int fp, mode;
212 int ok = 1;
213
214 printk("Backtrace: ");
215
216 if (!tsk)
217 tsk = current;
218
219 if (regs) {
220 fp = frame_pointer(regs);
221 mode = processor_mode(regs);
222 } else if (tsk != current) {
223 fp = thread_saved_fp(tsk);
224 mode = 0x10;
225 } else {
226 asm("mov %0, fp" : "=r" (fp) : : "cc");
227 mode = 0x10;
228 }
229
230 if (!fp) {
231 pr_cont("no frame pointer");
232 ok = 0;
233 } else if (verify_stack(fp)) {
234 pr_cont("invalid frame pointer 0x%08x", fp);
235 ok = 0;
236 } else if (fp < (unsigned long)end_of_stack(tsk))
237 pr_cont("frame pointer underflow");
238 pr_cont("\n");
239
240 if (ok)
241 c_backtrace(fp, mode);
242}
243#endif
244
245void show_stack(struct task_struct *tsk, unsigned long *sp)
246{
247 dump_backtrace(NULL, tsk);
248 barrier();
249}
250
251#ifdef CONFIG_PREEMPT
252#define S_PREEMPT " PREEMPT"
253#else
254#define S_PREEMPT ""
255#endif
256#ifdef CONFIG_SMP
257#define S_SMP " SMP"
258#else
259#define S_SMP ""
260#endif
261#ifdef CONFIG_THUMB2_KERNEL
262#define S_ISA " THUMB2"
263#else
264#define S_ISA " ARM"
265#endif
266
267static int __die(const char *str, int err, struct pt_regs *regs)
268{
269 struct task_struct *tsk = current;
270 static int die_counter;
271 int ret;
272
273 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP S_ISA "\n",
274 str, err, ++die_counter);
275
276
277 ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV);
278 if (ret == NOTIFY_STOP)
279 return 1;
280
281 print_modules();
282 __show_regs(regs);
283 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
284 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk));
285
286 if (!user_mode(regs) || in_interrupt()) {
287 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp,
288 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
289 dump_backtrace(regs, tsk);
290 dump_instr(KERN_EMERG, regs);
291 }
292
293 return 0;
294}
295
296static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
297static int die_owner = -1;
298static unsigned int die_nest_count;
299
300static unsigned long oops_begin(void)
301{
302 int cpu;
303 unsigned long flags;
304
305 oops_enter();
306
307
308 raw_local_irq_save(flags);
309 cpu = smp_processor_id();
310 if (!arch_spin_trylock(&die_lock)) {
311 if (cpu == die_owner)
312 ;
313 else
314 arch_spin_lock(&die_lock);
315 }
316 die_nest_count++;
317 die_owner = cpu;
318 console_verbose();
319 bust_spinlocks(1);
320 return flags;
321}
322
323static void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
324{
325 if (regs && kexec_should_crash(current))
326 crash_kexec(regs);
327
328 bust_spinlocks(0);
329 die_owner = -1;
330 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
331 die_nest_count--;
332 if (!die_nest_count)
333
334 arch_spin_unlock(&die_lock);
335 raw_local_irq_restore(flags);
336 oops_exit();
337
338 if (in_interrupt())
339 panic("Fatal exception in interrupt");
340 if (panic_on_oops)
341 panic("Fatal exception");
342 if (signr)
343 do_exit(signr);
344}
345
346
347
348
349void die(const char *str, struct pt_regs *regs, int err)
350{
351 enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE;
352 unsigned long flags = oops_begin();
353 int sig = SIGSEGV;
354
355 if (!user_mode(regs))
356 bug_type = report_bug(regs->ARM_pc, regs);
357 if (bug_type != BUG_TRAP_TYPE_NONE)
358 str = "Oops - BUG";
359
360 if (__die(str, err, regs))
361 sig = 0;
362
363 oops_end(flags, regs, sig);
364}
365
366void arm_notify_die(const char *str, struct pt_regs *regs,
367 struct siginfo *info, unsigned long err, unsigned long trap)
368{
369 if (user_mode(regs)) {
370 current->thread.error_code = err;
371 current->thread.trap_no = trap;
372
373 force_sig_info(info->si_signo, info, current);
374 } else {
375 die(str, regs, err);
376 }
377}
378
379#ifdef CONFIG_GENERIC_BUG
380
381int is_valid_bugaddr(unsigned long pc)
382{
383#ifdef CONFIG_THUMB2_KERNEL
384 u16 bkpt;
385 u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE);
386#else
387 u32 bkpt;
388 u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE);
389#endif
390
391 if (probe_kernel_address((unsigned *)pc, bkpt))
392 return 0;
393
394 return bkpt == insn;
395}
396
397#endif
398
399static LIST_HEAD(undef_hook);
400static DEFINE_RAW_SPINLOCK(undef_lock);
401
402void register_undef_hook(struct undef_hook *hook)
403{
404 unsigned long flags;
405
406 raw_spin_lock_irqsave(&undef_lock, flags);
407 list_add(&hook->node, &undef_hook);
408 raw_spin_unlock_irqrestore(&undef_lock, flags);
409}
410
411void unregister_undef_hook(struct undef_hook *hook)
412{
413 unsigned long flags;
414
415 raw_spin_lock_irqsave(&undef_lock, flags);
416 list_del(&hook->node);
417 raw_spin_unlock_irqrestore(&undef_lock, flags);
418}
419
420static int call_undef_hook(struct pt_regs *regs, unsigned int instr)
421{
422 struct undef_hook *hook;
423 unsigned long flags;
424 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL;
425
426 raw_spin_lock_irqsave(&undef_lock, flags);
427 list_for_each_entry(hook, &undef_hook, node)
428 if ((instr & hook->instr_mask) == hook->instr_val &&
429 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val)
430 fn = hook->fn;
431 raw_spin_unlock_irqrestore(&undef_lock, flags);
432
433 return fn ? fn(regs, instr) : 1;
434}
435
436asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
437{
438 unsigned int instr;
439 siginfo_t info;
440 void __user *pc;
441
442 pc = (void __user *)instruction_pointer(regs);
443
444 if (processor_mode(regs) == SVC_MODE) {
445#ifdef CONFIG_THUMB2_KERNEL
446 if (thumb_mode(regs)) {
447 instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]);
448 if (is_wide_instruction(instr)) {
449 u16 inst2;
450 inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]);
451 instr = __opcode_thumb32_compose(instr, inst2);
452 }
453 } else
454#endif
455 instr = __mem_to_opcode_arm(*(u32 *) pc);
456 } else if (thumb_mode(regs)) {
457 if (get_user(instr, (u16 __user *)pc))
458 goto die_sig;
459 instr = __mem_to_opcode_thumb16(instr);
460 if (is_wide_instruction(instr)) {
461 unsigned int instr2;
462 if (get_user(instr2, (u16 __user *)pc+1))
463 goto die_sig;
464 instr2 = __mem_to_opcode_thumb16(instr2);
465 instr = __opcode_thumb32_compose(instr, instr2);
466 }
467 } else {
468 if (get_user(instr, (u32 __user *)pc))
469 goto die_sig;
470 instr = __mem_to_opcode_arm(instr);
471 }
472
473 if (call_undef_hook(regs, instr) == 0)
474 return;
475
476die_sig:
477#ifdef CONFIG_DEBUG_USER
478 if (user_debug & UDBG_UNDEFINED) {
479 pr_info("%s (%d): undefined instruction: pc=%p\n",
480 current->comm, task_pid_nr(current), pc);
481 __show_regs(regs);
482 dump_instr(KERN_INFO, regs);
483 }
484#endif
485
486 info.si_signo = SIGILL;
487 info.si_errno = 0;
488 info.si_code = ILL_ILLOPC;
489 info.si_addr = pc;
490
491 arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6);
492}
493
494
495
496
497
498
499
500
501
502
503
504
505
506asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs)
507{
508 struct pt_regs *old_regs = set_irq_regs(regs);
509
510 nmi_enter();
511
512
513
514 nmi_exit();
515
516 set_irq_regs(old_regs);
517}
518
519
520
521
522
523
524
525asmlinkage void bad_mode(struct pt_regs *regs, int reason)
526{
527 console_verbose();
528
529 pr_crit("Bad mode in %s handler detected\n", handler[reason]);
530
531 die("Oops - bad mode", regs, 0);
532 local_irq_disable();
533 panic("bad mode");
534}
535
536static int bad_syscall(int n, struct pt_regs *regs)
537{
538 siginfo_t info;
539
540 if ((current->personality & PER_MASK) != PER_LINUX) {
541 send_sig(SIGSEGV, current, 1);
542 return regs->ARM_r0;
543 }
544
545#ifdef CONFIG_DEBUG_USER
546 if (user_debug & UDBG_SYSCALL) {
547 pr_err("[%d] %s: obsolete system call %08x.\n",
548 task_pid_nr(current), current->comm, n);
549 dump_instr(KERN_ERR, regs);
550 }
551#endif
552
553 info.si_signo = SIGILL;
554 info.si_errno = 0;
555 info.si_code = ILL_ILLTRP;
556 info.si_addr = (void __user *)instruction_pointer(regs) -
557 (thumb_mode(regs) ? 2 : 4);
558
559 arm_notify_die("Oops - bad syscall", regs, &info, 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_cache_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(VERIFY_READ, start, end - start))
593 return -EFAULT;
594
595 return __do_cache_op(start, end);
596}
597
598
599
600
601
602#define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
603asmlinkage int arm_syscall(int no, struct pt_regs *regs)
604{
605 siginfo_t info;
606
607 if ((no >> 16) != (__ARM_NR_BASE>> 16))
608 return bad_syscall(no, regs);
609
610 switch (no & 0xffff) {
611 case 0:
612 info.si_signo = SIGSEGV;
613 info.si_errno = 0;
614 info.si_code = SEGV_MAPERR;
615 info.si_addr = NULL;
616
617 arm_notify_die("branch through zero", regs, &info, 0, 0);
618 return 0;
619
620 case NR(breakpoint):
621 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
622 ptrace_break(current, regs);
623 return regs->ARM_r0;
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639 case NR(cacheflush):
640 return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
641
642 case NR(usr26):
643 if (!(elf_hwcap & HWCAP_26BIT))
644 break;
645 regs->ARM_cpsr &= ~MODE32_BIT;
646 return regs->ARM_r0;
647
648 case NR(usr32):
649 if (!(elf_hwcap & HWCAP_26BIT))
650 break;
651 regs->ARM_cpsr |= MODE32_BIT;
652 return regs->ARM_r0;
653
654 case NR(set_tls):
655 set_tls(regs->ARM_r0);
656 return 0;
657
658 default:
659
660
661
662
663 if ((no & 0xffff) <= 0x7ff)
664 return -ENOSYS;
665 break;
666 }
667#ifdef CONFIG_DEBUG_USER
668
669
670
671
672 if (user_debug & UDBG_SYSCALL) {
673 pr_err("[%d] %s: arm syscall %d\n",
674 task_pid_nr(current), current->comm, no);
675 dump_instr("", regs);
676 if (user_mode(regs)) {
677 __show_regs(regs);
678 c_backtrace(frame_pointer(regs), processor_mode(regs));
679 }
680 }
681#endif
682 info.si_signo = SIGILL;
683 info.si_errno = 0;
684 info.si_code = ILL_ILLTRP;
685 info.si_addr = (void __user *)instruction_pointer(regs) -
686 (thumb_mode(regs) ? 2 : 4);
687
688 arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0);
689 return 0;
690}
691
692#ifdef CONFIG_TLS_REG_EMUL
693
694
695
696
697
698
699
700
701
702static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
703{
704 int reg = (instr >> 12) & 15;
705 if (reg == 15)
706 return 1;
707 regs->uregs[reg] = current_thread_info()->tp_value[0];
708 regs->ARM_pc += 4;
709 return 0;
710}
711
712static struct undef_hook arm_mrc_hook = {
713 .instr_mask = 0x0fff0fff,
714 .instr_val = 0x0e1d0f70,
715 .cpsr_mask = PSR_T_BIT,
716 .cpsr_val = 0,
717 .fn = get_tp_trap,
718};
719
720static int __init arm_mrc_hook_init(void)
721{
722 register_undef_hook(&arm_mrc_hook);
723 return 0;
724}
725
726late_initcall(arm_mrc_hook_init);
727
728#endif
729
730
731
732
733
734asmlinkage void
735baddataabort(int code, unsigned long instr, struct pt_regs *regs)
736{
737 unsigned long addr = instruction_pointer(regs);
738 siginfo_t info;
739
740#ifdef CONFIG_DEBUG_USER
741 if (user_debug & UDBG_BADABORT) {
742 pr_err("[%d] %s: bad data abort: code %d instr 0x%08lx\n",
743 task_pid_nr(current), current->comm, code, instr);
744 dump_instr(KERN_ERR, regs);
745 show_pte(current->mm, addr);
746 }
747#endif
748
749 info.si_signo = SIGILL;
750 info.si_errno = 0;
751 info.si_code = ILL_ILLOPC;
752 info.si_addr = (void __user *)addr;
753
754 arm_notify_die("unknown data abort code", regs, &info, instr, 0);
755}
756
757void __readwrite_bug(const char *fn)
758{
759 pr_err("%s called, but not implemented\n", fn);
760 BUG();
761}
762EXPORT_SYMBOL(__readwrite_bug);
763
764void __pte_error(const char *file, int line, pte_t pte)
765{
766 pr_err("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte));
767}
768
769void __pmd_error(const char *file, int line, pmd_t pmd)
770{
771 pr_err("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd));
772}
773
774void __pgd_error(const char *file, int line, pgd_t pgd)
775{
776 pr_err("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd));
777}
778
779asmlinkage void __div0(void)
780{
781 pr_err("Division by zero in kernel.\n");
782 dump_stack();
783}
784EXPORT_SYMBOL(__div0);
785
786void abort(void)
787{
788 BUG();
789
790
791 panic("Oops failed to kill thread");
792}
793EXPORT_SYMBOL(abort);
794
795void __init trap_init(void)
796{
797 return;
798}
799
800#ifdef CONFIG_KUSER_HELPERS
801static void __init kuser_init(void *vectors)
802{
803 extern char __kuser_helper_start[], __kuser_helper_end[];
804 int kuser_sz = __kuser_helper_end - __kuser_helper_start;
805
806 memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
807
808
809
810
811
812 if (tls_emu || has_tls_reg)
813 memcpy(vectors + 0xfe0, vectors + 0xfe8, 4);
814}
815#else
816static inline void __init kuser_init(void *vectors)
817{
818}
819#endif
820
821void __init early_trap_init(void *vectors_base)
822{
823#ifndef CONFIG_CPU_V7M
824 unsigned long vectors = (unsigned long)vectors_base;
825 extern char __stubs_start[], __stubs_end[];
826 extern char __vectors_start[], __vectors_end[];
827 unsigned i;
828
829 vectors_page = vectors_base;
830
831
832
833
834
835
836
837 for (i = 0; i < PAGE_SIZE / sizeof(u32); i++)
838 ((u32 *)vectors_base)[i] = 0xe7fddef1;
839
840
841
842
843
844
845 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
846 memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start);
847
848 kuser_init(vectors_base);
849
850 flush_icache_range(vectors, vectors + PAGE_SIZE * 2);
851#else
852
853
854
855
856
857#endif
858}
859