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[deliverable/linux.git] / arch / arm64 / kernel / traps.c
1 /*
2 * Based on arch/arm/kernel/traps.c
3 *
4 * Copyright (C) 1995-2009 Russell King
5 * Copyright (C) 2012 ARM Ltd.
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 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 */
19
20 #include <linux/bug.h>
21 #include <linux/signal.h>
22 #include <linux/personality.h>
23 #include <linux/kallsyms.h>
24 #include <linux/spinlock.h>
25 #include <linux/uaccess.h>
26 #include <linux/hardirq.h>
27 #include <linux/kdebug.h>
28 #include <linux/module.h>
29 #include <linux/kexec.h>
30 #include <linux/delay.h>
31 #include <linux/init.h>
32 #include <linux/sched.h>
33 #include <linux/syscalls.h>
34
35 #include <asm/atomic.h>
36 #include <asm/bug.h>
37 #include <asm/debug-monitors.h>
38 #include <asm/esr.h>
39 #include <asm/insn.h>
40 #include <asm/traps.h>
41 #include <asm/stacktrace.h>
42 #include <asm/exception.h>
43 #include <asm/system_misc.h>
44 #include <asm/sysreg.h>
45
46 static const char *handler[]= {
47 "Synchronous Abort",
48 "IRQ",
49 "FIQ",
50 "Error"
51 };
52
53 int show_unhandled_signals = 1;
54
55 /*
56 * Dump out the contents of some kernel memory nicely...
57 */
58 static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
59 unsigned long top)
60 {
61 unsigned long first;
62 mm_segment_t fs;
63 int i;
64
65 /*
66 * We need to switch to kernel mode so that we can use __get_user
67 * to safely read from kernel space.
68 */
69 fs = get_fs();
70 set_fs(KERNEL_DS);
71
72 printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top);
73
74 for (first = bottom & ~31; first < top; first += 32) {
75 unsigned long p;
76 char str[sizeof(" 12345678") * 8 + 1];
77
78 memset(str, ' ', sizeof(str));
79 str[sizeof(str) - 1] = '\0';
80
81 for (p = first, i = 0; i < (32 / 8)
82 && p < top; i++, p += 8) {
83 if (p >= bottom && p < top) {
84 unsigned long val;
85
86 if (__get_user(val, (unsigned long *)p) == 0)
87 sprintf(str + i * 17, " %016lx", val);
88 else
89 sprintf(str + i * 17, " ????????????????");
90 }
91 }
92 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
93 }
94
95 set_fs(fs);
96 }
97
98 static void dump_backtrace_entry(unsigned long where)
99 {
100 /*
101 * Note that 'where' can have a physical address, but it's not handled.
102 */
103 print_ip_sym(where);
104 }
105
106 static void __dump_instr(const char *lvl, struct pt_regs *regs)
107 {
108 unsigned long addr = instruction_pointer(regs);
109 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
110 int i;
111
112 for (i = -4; i < 1; i++) {
113 unsigned int val, bad;
114
115 bad = __get_user(val, &((u32 *)addr)[i]);
116
117 if (!bad)
118 p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
119 else {
120 p += sprintf(p, "bad PC value");
121 break;
122 }
123 }
124 printk("%sCode: %s\n", lvl, str);
125 }
126
127 static void dump_instr(const char *lvl, struct pt_regs *regs)
128 {
129 if (!user_mode(regs)) {
130 mm_segment_t fs = get_fs();
131 set_fs(KERNEL_DS);
132 __dump_instr(lvl, regs);
133 set_fs(fs);
134 } else {
135 __dump_instr(lvl, regs);
136 }
137 }
138
139 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
140 {
141 struct stackframe frame;
142 unsigned long irq_stack_ptr;
143 int skip;
144
145 /*
146 * Switching between stacks is valid when tracing current and in
147 * non-preemptible context.
148 */
149 if (tsk == current && !preemptible())
150 irq_stack_ptr = IRQ_STACK_PTR(smp_processor_id());
151 else
152 irq_stack_ptr = 0;
153
154 pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
155
156 if (!tsk)
157 tsk = current;
158
159 if (tsk == current) {
160 frame.fp = (unsigned long)__builtin_frame_address(0);
161 frame.sp = current_stack_pointer;
162 frame.pc = (unsigned long)dump_backtrace;
163 } else {
164 /*
165 * task blocked in __switch_to
166 */
167 frame.fp = thread_saved_fp(tsk);
168 frame.sp = thread_saved_sp(tsk);
169 frame.pc = thread_saved_pc(tsk);
170 }
171 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
172 frame.graph = tsk->curr_ret_stack;
173 #endif
174
175 skip = !!regs;
176 printk("Call trace:\n");
177 while (1) {
178 unsigned long where = frame.pc;
179 unsigned long stack;
180 int ret;
181
182 /* skip until specified stack frame */
183 if (!skip) {
184 dump_backtrace_entry(where);
185 } else if (frame.fp == regs->regs[29]) {
186 skip = 0;
187 /*
188 * Mostly, this is the case where this function is
189 * called in panic/abort. As exception handler's
190 * stack frame does not contain the corresponding pc
191 * at which an exception has taken place, use regs->pc
192 * instead.
193 */
194 dump_backtrace_entry(regs->pc);
195 }
196 ret = unwind_frame(tsk, &frame);
197 if (ret < 0)
198 break;
199 stack = frame.sp;
200 if (in_exception_text(where)) {
201 /*
202 * If we switched to the irq_stack before calling this
203 * exception handler, then the pt_regs will be on the
204 * task stack. The easiest way to tell is if the large
205 * pt_regs would overlap with the end of the irq_stack.
206 */
207 if (stack < irq_stack_ptr &&
208 (stack + sizeof(struct pt_regs)) > irq_stack_ptr)
209 stack = IRQ_STACK_TO_TASK_STACK(irq_stack_ptr);
210
211 dump_mem("", "Exception stack", stack,
212 stack + sizeof(struct pt_regs));
213 }
214 }
215 }
216
217 void show_stack(struct task_struct *tsk, unsigned long *sp)
218 {
219 dump_backtrace(NULL, tsk);
220 barrier();
221 }
222
223 #ifdef CONFIG_PREEMPT
224 #define S_PREEMPT " PREEMPT"
225 #else
226 #define S_PREEMPT ""
227 #endif
228 #define S_SMP " SMP"
229
230 static int __die(const char *str, int err, struct thread_info *thread,
231 struct pt_regs *regs)
232 {
233 struct task_struct *tsk = thread->task;
234 static int die_counter;
235 int ret;
236
237 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
238 str, err, ++die_counter);
239
240 /* trap and error numbers are mostly meaningless on ARM */
241 ret = notify_die(DIE_OOPS, str, regs, err, 0, SIGSEGV);
242 if (ret == NOTIFY_STOP)
243 return ret;
244
245 print_modules();
246 __show_regs(regs);
247 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
248 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1);
249
250 if (!user_mode(regs)) {
251 dump_mem(KERN_EMERG, "Stack: ", regs->sp,
252 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
253 dump_backtrace(regs, tsk);
254 dump_instr(KERN_EMERG, regs);
255 }
256
257 return ret;
258 }
259
260 static DEFINE_RAW_SPINLOCK(die_lock);
261
262 /*
263 * This function is protected against re-entrancy.
264 */
265 void die(const char *str, struct pt_regs *regs, int err)
266 {
267 struct thread_info *thread = current_thread_info();
268 int ret;
269
270 oops_enter();
271
272 raw_spin_lock_irq(&die_lock);
273 console_verbose();
274 bust_spinlocks(1);
275 ret = __die(str, err, thread, regs);
276
277 if (regs && kexec_should_crash(thread->task))
278 crash_kexec(regs);
279
280 bust_spinlocks(0);
281 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
282 raw_spin_unlock_irq(&die_lock);
283 oops_exit();
284
285 if (in_interrupt())
286 panic("Fatal exception in interrupt");
287 if (panic_on_oops)
288 panic("Fatal exception");
289 if (ret != NOTIFY_STOP)
290 do_exit(SIGSEGV);
291 }
292
293 void arm64_notify_die(const char *str, struct pt_regs *regs,
294 struct siginfo *info, int err)
295 {
296 if (user_mode(regs)) {
297 current->thread.fault_address = 0;
298 current->thread.fault_code = err;
299 force_sig_info(info->si_signo, info, current);
300 } else {
301 die(str, regs, err);
302 }
303 }
304
305 static LIST_HEAD(undef_hook);
306 static DEFINE_RAW_SPINLOCK(undef_lock);
307
308 void register_undef_hook(struct undef_hook *hook)
309 {
310 unsigned long flags;
311
312 raw_spin_lock_irqsave(&undef_lock, flags);
313 list_add(&hook->node, &undef_hook);
314 raw_spin_unlock_irqrestore(&undef_lock, flags);
315 }
316
317 void unregister_undef_hook(struct undef_hook *hook)
318 {
319 unsigned long flags;
320
321 raw_spin_lock_irqsave(&undef_lock, flags);
322 list_del(&hook->node);
323 raw_spin_unlock_irqrestore(&undef_lock, flags);
324 }
325
326 static int call_undef_hook(struct pt_regs *regs)
327 {
328 struct undef_hook *hook;
329 unsigned long flags;
330 u32 instr;
331 int (*fn)(struct pt_regs *regs, u32 instr) = NULL;
332 void __user *pc = (void __user *)instruction_pointer(regs);
333
334 if (!user_mode(regs))
335 return 1;
336
337 if (compat_thumb_mode(regs)) {
338 /* 16-bit Thumb instruction */
339 if (get_user(instr, (u16 __user *)pc))
340 goto exit;
341 instr = le16_to_cpu(instr);
342 if (aarch32_insn_is_wide(instr)) {
343 u32 instr2;
344
345 if (get_user(instr2, (u16 __user *)(pc + 2)))
346 goto exit;
347 instr2 = le16_to_cpu(instr2);
348 instr = (instr << 16) | instr2;
349 }
350 } else {
351 /* 32-bit ARM instruction */
352 if (get_user(instr, (u32 __user *)pc))
353 goto exit;
354 instr = le32_to_cpu(instr);
355 }
356
357 raw_spin_lock_irqsave(&undef_lock, flags);
358 list_for_each_entry(hook, &undef_hook, node)
359 if ((instr & hook->instr_mask) == hook->instr_val &&
360 (regs->pstate & hook->pstate_mask) == hook->pstate_val)
361 fn = hook->fn;
362
363 raw_spin_unlock_irqrestore(&undef_lock, flags);
364 exit:
365 return fn ? fn(regs, instr) : 1;
366 }
367
368 static void force_signal_inject(int signal, int code, struct pt_regs *regs,
369 unsigned long address)
370 {
371 siginfo_t info;
372 void __user *pc = (void __user *)instruction_pointer(regs);
373 const char *desc;
374
375 switch (signal) {
376 case SIGILL:
377 desc = "undefined instruction";
378 break;
379 case SIGSEGV:
380 desc = "illegal memory access";
381 break;
382 default:
383 desc = "bad mode";
384 break;
385 }
386
387 if (unhandled_signal(current, signal) &&
388 show_unhandled_signals_ratelimited()) {
389 pr_info("%s[%d]: %s: pc=%p\n",
390 current->comm, task_pid_nr(current), desc, pc);
391 dump_instr(KERN_INFO, regs);
392 }
393
394 info.si_signo = signal;
395 info.si_errno = 0;
396 info.si_code = code;
397 info.si_addr = pc;
398
399 arm64_notify_die(desc, regs, &info, 0);
400 }
401
402 /*
403 * Set up process info to signal segmentation fault - called on access error.
404 */
405 void arm64_notify_segfault(struct pt_regs *regs, unsigned long addr)
406 {
407 int code;
408
409 down_read(&current->mm->mmap_sem);
410 if (find_vma(current->mm, addr) == NULL)
411 code = SEGV_MAPERR;
412 else
413 code = SEGV_ACCERR;
414 up_read(&current->mm->mmap_sem);
415
416 force_signal_inject(SIGSEGV, code, regs, addr);
417 }
418
419 asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
420 {
421 /* check for AArch32 breakpoint instructions */
422 if (!aarch32_break_handler(regs))
423 return;
424
425 if (call_undef_hook(regs) == 0)
426 return;
427
428 force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
429 }
430
431 void cpu_enable_cache_maint_trap(void *__unused)
432 {
433 config_sctlr_el1(SCTLR_EL1_UCI, 0);
434 }
435
436 #define __user_cache_maint(insn, address, res) \
437 asm volatile ( \
438 "1: " insn ", %1\n" \
439 " mov %w0, #0\n" \
440 "2:\n" \
441 " .pushsection .fixup,\"ax\"\n" \
442 " .align 2\n" \
443 "3: mov %w0, %w2\n" \
444 " b 2b\n" \
445 " .popsection\n" \
446 _ASM_EXTABLE(1b, 3b) \
447 : "=r" (res) \
448 : "r" (address), "i" (-EFAULT) )
449
450 asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
451 {
452 unsigned long address;
453 int ret;
454
455 /* if this is a write with: Op0=1, Op2=1, Op1=3, CRn=7 */
456 if ((esr & 0x01fffc01) == 0x0012dc00) {
457 int rt = (esr >> 5) & 0x1f;
458 int crm = (esr >> 1) & 0x0f;
459
460 address = (rt == 31) ? 0 : regs->regs[rt];
461
462 switch (crm) {
463 case 11: /* DC CVAU, gets promoted */
464 __user_cache_maint("dc civac", address, ret);
465 break;
466 case 10: /* DC CVAC, gets promoted */
467 __user_cache_maint("dc civac", address, ret);
468 break;
469 case 14: /* DC CIVAC */
470 __user_cache_maint("dc civac", address, ret);
471 break;
472 case 5: /* IC IVAU */
473 __user_cache_maint("ic ivau", address, ret);
474 break;
475 default:
476 force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
477 return;
478 }
479 } else {
480 force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
481 return;
482 }
483
484 if (ret)
485 arm64_notify_segfault(regs, address);
486 else
487 regs->pc += 4;
488 }
489
490 long compat_arm_syscall(struct pt_regs *regs);
491
492 asmlinkage long do_ni_syscall(struct pt_regs *regs)
493 {
494 #ifdef CONFIG_COMPAT
495 long ret;
496 if (is_compat_task()) {
497 ret = compat_arm_syscall(regs);
498 if (ret != -ENOSYS)
499 return ret;
500 }
501 #endif
502
503 if (show_unhandled_signals_ratelimited()) {
504 pr_info("%s[%d]: syscall %d\n", current->comm,
505 task_pid_nr(current), (int)regs->syscallno);
506 dump_instr("", regs);
507 if (user_mode(regs))
508 __show_regs(regs);
509 }
510
511 return sys_ni_syscall();
512 }
513
514 static const char *esr_class_str[] = {
515 [0 ... ESR_ELx_EC_MAX] = "UNRECOGNIZED EC",
516 [ESR_ELx_EC_UNKNOWN] = "Unknown/Uncategorized",
517 [ESR_ELx_EC_WFx] = "WFI/WFE",
518 [ESR_ELx_EC_CP15_32] = "CP15 MCR/MRC",
519 [ESR_ELx_EC_CP15_64] = "CP15 MCRR/MRRC",
520 [ESR_ELx_EC_CP14_MR] = "CP14 MCR/MRC",
521 [ESR_ELx_EC_CP14_LS] = "CP14 LDC/STC",
522 [ESR_ELx_EC_FP_ASIMD] = "ASIMD",
523 [ESR_ELx_EC_CP10_ID] = "CP10 MRC/VMRS",
524 [ESR_ELx_EC_CP14_64] = "CP14 MCRR/MRRC",
525 [ESR_ELx_EC_ILL] = "PSTATE.IL",
526 [ESR_ELx_EC_SVC32] = "SVC (AArch32)",
527 [ESR_ELx_EC_HVC32] = "HVC (AArch32)",
528 [ESR_ELx_EC_SMC32] = "SMC (AArch32)",
529 [ESR_ELx_EC_SVC64] = "SVC (AArch64)",
530 [ESR_ELx_EC_HVC64] = "HVC (AArch64)",
531 [ESR_ELx_EC_SMC64] = "SMC (AArch64)",
532 [ESR_ELx_EC_SYS64] = "MSR/MRS (AArch64)",
533 [ESR_ELx_EC_IMP_DEF] = "EL3 IMP DEF",
534 [ESR_ELx_EC_IABT_LOW] = "IABT (lower EL)",
535 [ESR_ELx_EC_IABT_CUR] = "IABT (current EL)",
536 [ESR_ELx_EC_PC_ALIGN] = "PC Alignment",
537 [ESR_ELx_EC_DABT_LOW] = "DABT (lower EL)",
538 [ESR_ELx_EC_DABT_CUR] = "DABT (current EL)",
539 [ESR_ELx_EC_SP_ALIGN] = "SP Alignment",
540 [ESR_ELx_EC_FP_EXC32] = "FP (AArch32)",
541 [ESR_ELx_EC_FP_EXC64] = "FP (AArch64)",
542 [ESR_ELx_EC_SERROR] = "SError",
543 [ESR_ELx_EC_BREAKPT_LOW] = "Breakpoint (lower EL)",
544 [ESR_ELx_EC_BREAKPT_CUR] = "Breakpoint (current EL)",
545 [ESR_ELx_EC_SOFTSTP_LOW] = "Software Step (lower EL)",
546 [ESR_ELx_EC_SOFTSTP_CUR] = "Software Step (current EL)",
547 [ESR_ELx_EC_WATCHPT_LOW] = "Watchpoint (lower EL)",
548 [ESR_ELx_EC_WATCHPT_CUR] = "Watchpoint (current EL)",
549 [ESR_ELx_EC_BKPT32] = "BKPT (AArch32)",
550 [ESR_ELx_EC_VECTOR32] = "Vector catch (AArch32)",
551 [ESR_ELx_EC_BRK64] = "BRK (AArch64)",
552 };
553
554 const char *esr_get_class_string(u32 esr)
555 {
556 return esr_class_str[ESR_ELx_EC(esr)];
557 }
558
559 /*
560 * bad_mode handles the impossible case in the exception vector.
561 */
562 asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
563 {
564 siginfo_t info;
565 void __user *pc = (void __user *)instruction_pointer(regs);
566 console_verbose();
567
568 pr_crit("Bad mode in %s handler detected on CPU%d, code 0x%08x -- %s\n",
569 handler[reason], smp_processor_id(), esr,
570 esr_get_class_string(esr));
571 __show_regs(regs);
572
573 info.si_signo = SIGILL;
574 info.si_errno = 0;
575 info.si_code = ILL_ILLOPC;
576 info.si_addr = pc;
577
578 arm64_notify_die("Oops - bad mode", regs, &info, 0);
579 }
580
581 void __pte_error(const char *file, int line, unsigned long val)
582 {
583 pr_err("%s:%d: bad pte %016lx.\n", file, line, val);
584 }
585
586 void __pmd_error(const char *file, int line, unsigned long val)
587 {
588 pr_err("%s:%d: bad pmd %016lx.\n", file, line, val);
589 }
590
591 void __pud_error(const char *file, int line, unsigned long val)
592 {
593 pr_err("%s:%d: bad pud %016lx.\n", file, line, val);
594 }
595
596 void __pgd_error(const char *file, int line, unsigned long val)
597 {
598 pr_err("%s:%d: bad pgd %016lx.\n", file, line, val);
599 }
600
601 /* GENERIC_BUG traps */
602
603 int is_valid_bugaddr(unsigned long addr)
604 {
605 /*
606 * bug_handler() only called for BRK #BUG_BRK_IMM.
607 * So the answer is trivial -- any spurious instances with no
608 * bug table entry will be rejected by report_bug() and passed
609 * back to the debug-monitors code and handled as a fatal
610 * unexpected debug exception.
611 */
612 return 1;
613 }
614
615 static int bug_handler(struct pt_regs *regs, unsigned int esr)
616 {
617 if (user_mode(regs))
618 return DBG_HOOK_ERROR;
619
620 switch (report_bug(regs->pc, regs)) {
621 case BUG_TRAP_TYPE_BUG:
622 die("Oops - BUG", regs, 0);
623 break;
624
625 case BUG_TRAP_TYPE_WARN:
626 /* Ideally, report_bug() should backtrace for us... but no. */
627 dump_backtrace(regs, NULL);
628 break;
629
630 default:
631 /* unknown/unrecognised bug trap type */
632 return DBG_HOOK_ERROR;
633 }
634
635 /* If thread survives, skip over the BUG instruction and continue: */
636 regs->pc += AARCH64_INSN_SIZE; /* skip BRK and resume */
637 return DBG_HOOK_HANDLED;
638 }
639
640 static struct break_hook bug_break_hook = {
641 .esr_val = 0xf2000000 | BUG_BRK_IMM,
642 .esr_mask = 0xffffffff,
643 .fn = bug_handler,
644 };
645
646 /*
647 * Initial handler for AArch64 BRK exceptions
648 * This handler only used until debug_traps_init().
649 */
650 int __init early_brk64(unsigned long addr, unsigned int esr,
651 struct pt_regs *regs)
652 {
653 return bug_handler(regs, esr) != DBG_HOOK_HANDLED;
654 }
655
656 /* This registration must happen early, before debug_traps_init(). */
657 void __init trap_init(void)
658 {
659 register_break_hook(&bug_break_hook);
660 }
Linux kernel - Deliverables
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