ca7f0ac5f70807ca2770ba646770e7cb82f235af
[firefly-linux-kernel-4.4.55.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
45 static const char *handler[]= {
46         "Synchronous Abort",
47         "IRQ",
48         "FIQ",
49         "Error"
50 };
51
52 int show_unhandled_signals = 1;
53
54 /*
55  * Dump out the contents of some memory nicely...
56  */
57 static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
58                      unsigned long top, bool compat)
59 {
60         unsigned long first;
61         mm_segment_t fs;
62         int i;
63         unsigned int width = compat ? 4 : 8;
64
65         /*
66          * We need to switch to kernel mode so that we can use __get_user
67          * to safely read from kernel space.  Note that we now dump the
68          * code first, just in case the backtrace kills us.
69          */
70         fs = get_fs();
71         set_fs(KERNEL_DS);
72
73         printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top);
74
75         for (first = bottom & ~31; first < top; first += 32) {
76                 unsigned long p;
77                 char str[sizeof(" 12345678") * 8 + 1];
78
79                 memset(str, ' ', sizeof(str));
80                 str[sizeof(str) - 1] = '\0';
81
82                 for (p = first, i = 0; i < (32 / width)
83                                         && p < top; i++, p += width) {
84                         if (p >= bottom && p < top) {
85                                 unsigned long val;
86
87                                 if (width == 8) {
88                                         if (__get_user(val, (unsigned long *)p) == 0)
89                                                 sprintf(str + i * 17, " %016lx", val);
90                                         else
91                                                 sprintf(str + i * 17, " ????????????????");
92                                 } else {
93                                         if (__get_user(val, (unsigned int *)p) == 0)
94                                                 sprintf(str + i * 9, " %08lx", val);
95                                         else
96                                                 sprintf(str + i * 9, " ????????");
97                                 }
98                         }
99                 }
100                 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
101         }
102
103         set_fs(fs);
104 }
105
106 static void dump_backtrace_entry(unsigned long where)
107 {
108         /*
109          * Note that 'where' can have a physical address, but it's not handled.
110          */
111         print_ip_sym(where);
112 }
113
114 static void dump_instr(const char *lvl, struct pt_regs *regs)
115 {
116         unsigned long addr = instruction_pointer(regs);
117         mm_segment_t fs;
118         char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
119         int i;
120
121         /*
122          * We need to switch to kernel mode so that we can use __get_user
123          * to safely read from kernel space.  Note that we now dump the
124          * code first, just in case the backtrace kills us.
125          */
126         fs = get_fs();
127         set_fs(KERNEL_DS);
128
129         for (i = -4; i < 1; i++) {
130                 unsigned int val, bad;
131
132                 bad = __get_user(val, &((u32 *)addr)[i]);
133
134                 if (!bad)
135                         p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
136                 else {
137                         p += sprintf(p, "bad PC value");
138                         break;
139                 }
140         }
141         printk("%sCode: %s\n", lvl, str);
142
143         set_fs(fs);
144 }
145
146 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
147 {
148         struct stackframe frame;
149
150         pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
151
152         if (!tsk)
153                 tsk = current;
154
155         if (regs) {
156                 frame.fp = regs->regs[29];
157                 frame.sp = regs->sp;
158                 frame.pc = regs->pc;
159         } else 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
172         pr_emerg("Call trace:\n");
173         while (1) {
174                 unsigned long where = frame.pc;
175                 unsigned long stack;
176                 int ret;
177
178                 dump_backtrace_entry(where);
179                 ret = unwind_frame(&frame);
180                 if (ret < 0)
181                         break;
182                 stack = frame.sp;
183                 if (in_exception_text(where))
184                         dump_mem("", "Exception stack", stack,
185                                  stack + sizeof(struct pt_regs), false);
186         }
187 }
188
189 void show_stack(struct task_struct *tsk, unsigned long *sp)
190 {
191         dump_backtrace(NULL, tsk);
192         barrier();
193 }
194
195 #ifdef CONFIG_PREEMPT
196 #define S_PREEMPT " PREEMPT"
197 #else
198 #define S_PREEMPT ""
199 #endif
200 #define S_SMP " SMP"
201
202 static int __die(const char *str, int err, struct thread_info *thread,
203                  struct pt_regs *regs)
204 {
205         struct task_struct *tsk = thread->task;
206         static int die_counter;
207         int ret;
208
209         pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
210                  str, err, ++die_counter);
211
212         /* trap and error numbers are mostly meaningless on ARM */
213         ret = notify_die(DIE_OOPS, str, regs, err, 0, SIGSEGV);
214         if (ret == NOTIFY_STOP)
215                 return ret;
216
217         print_modules();
218         __show_regs(regs);
219         pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
220                  TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1);
221
222         if (!user_mode(regs) || in_interrupt()) {
223                 dump_mem(KERN_EMERG, "Stack: ", regs->sp,
224                          THREAD_SIZE + (unsigned long)task_stack_page(tsk),
225                          compat_user_mode(regs));
226                 dump_backtrace(regs, tsk);
227                 dump_instr(KERN_EMERG, regs);
228         }
229
230         return ret;
231 }
232
233 static DEFINE_RAW_SPINLOCK(die_lock);
234
235 /*
236  * This function is protected against re-entrancy.
237  */
238 void die(const char *str, struct pt_regs *regs, int err)
239 {
240         struct thread_info *thread = current_thread_info();
241         int ret;
242
243         oops_enter();
244
245         raw_spin_lock_irq(&die_lock);
246         console_verbose();
247         bust_spinlocks(1);
248         ret = __die(str, err, thread, regs);
249
250         if (regs && kexec_should_crash(thread->task))
251                 crash_kexec(regs);
252
253         bust_spinlocks(0);
254         add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
255         raw_spin_unlock_irq(&die_lock);
256         oops_exit();
257
258         if (in_interrupt())
259                 panic("Fatal exception in interrupt");
260         if (panic_on_oops)
261                 panic("Fatal exception");
262         if (ret != NOTIFY_STOP)
263                 do_exit(SIGSEGV);
264 }
265
266 void arm64_notify_die(const char *str, struct pt_regs *regs,
267                       struct siginfo *info, int err)
268 {
269         if (user_mode(regs)) {
270                 current->thread.fault_address = 0;
271                 current->thread.fault_code = err;
272                 force_sig_info(info->si_signo, info, current);
273         } else {
274                 die(str, regs, err);
275         }
276 }
277
278 static LIST_HEAD(undef_hook);
279 static DEFINE_RAW_SPINLOCK(undef_lock);
280
281 void register_undef_hook(struct undef_hook *hook)
282 {
283         unsigned long flags;
284
285         raw_spin_lock_irqsave(&undef_lock, flags);
286         list_add(&hook->node, &undef_hook);
287         raw_spin_unlock_irqrestore(&undef_lock, flags);
288 }
289
290 void unregister_undef_hook(struct undef_hook *hook)
291 {
292         unsigned long flags;
293
294         raw_spin_lock_irqsave(&undef_lock, flags);
295         list_del(&hook->node);
296         raw_spin_unlock_irqrestore(&undef_lock, flags);
297 }
298
299 static int call_undef_hook(struct pt_regs *regs)
300 {
301         struct undef_hook *hook;
302         unsigned long flags;
303         u32 instr;
304         int (*fn)(struct pt_regs *regs, u32 instr) = NULL;
305         void __user *pc = (void __user *)instruction_pointer(regs);
306
307         if (!user_mode(regs))
308                 return 1;
309
310         if (compat_thumb_mode(regs)) {
311                 /* 16-bit Thumb instruction */
312                 if (get_user(instr, (u16 __user *)pc))
313                         goto exit;
314                 instr = le16_to_cpu(instr);
315                 if (aarch32_insn_is_wide(instr)) {
316                         u32 instr2;
317
318                         if (get_user(instr2, (u16 __user *)(pc + 2)))
319                                 goto exit;
320                         instr2 = le16_to_cpu(instr2);
321                         instr = (instr << 16) | instr2;
322                 }
323         } else {
324                 /* 32-bit ARM instruction */
325                 if (get_user(instr, (u32 __user *)pc))
326                         goto exit;
327                 instr = le32_to_cpu(instr);
328         }
329
330         raw_spin_lock_irqsave(&undef_lock, flags);
331         list_for_each_entry(hook, &undef_hook, node)
332                 if ((instr & hook->instr_mask) == hook->instr_val &&
333                         (regs->pstate & hook->pstate_mask) == hook->pstate_val)
334                         fn = hook->fn;
335
336         raw_spin_unlock_irqrestore(&undef_lock, flags);
337 exit:
338         return fn ? fn(regs, instr) : 1;
339 }
340
341 asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
342 {
343         siginfo_t info;
344         void __user *pc = (void __user *)instruction_pointer(regs);
345
346         /* check for AArch32 breakpoint instructions */
347         if (!aarch32_break_handler(regs))
348                 return;
349
350         if (call_undef_hook(regs) == 0)
351                 return;
352
353         if (unhandled_signal(current, SIGILL) && show_unhandled_signals_ratelimited()) {
354                 pr_info("%s[%d]: undefined instruction: pc=%p\n",
355                         current->comm, task_pid_nr(current), pc);
356                 dump_instr(KERN_INFO, regs);
357         }
358
359         info.si_signo = SIGILL;
360         info.si_errno = 0;
361         info.si_code  = ILL_ILLOPC;
362         info.si_addr  = pc;
363
364         arm64_notify_die("Oops - undefined instruction", regs, &info, 0);
365 }
366
367 long compat_arm_syscall(struct pt_regs *regs);
368
369 asmlinkage long do_ni_syscall(struct pt_regs *regs)
370 {
371 #ifdef CONFIG_COMPAT
372         long ret;
373         if (is_compat_task()) {
374                 ret = compat_arm_syscall(regs);
375                 if (ret != -ENOSYS)
376                         return ret;
377         }
378 #endif
379
380         if (show_unhandled_signals_ratelimited()) {
381                 pr_info("%s[%d]: syscall %d\n", current->comm,
382                         task_pid_nr(current), (int)regs->syscallno);
383                 dump_instr("", regs);
384                 if (user_mode(regs))
385                         __show_regs(regs);
386         }
387
388         return sys_ni_syscall();
389 }
390
391 static const char *esr_class_str[] = {
392         [0 ... ESR_ELx_EC_MAX]          = "UNRECOGNIZED EC",
393         [ESR_ELx_EC_UNKNOWN]            = "Unknown/Uncategorized",
394         [ESR_ELx_EC_WFx]                = "WFI/WFE",
395         [ESR_ELx_EC_CP15_32]            = "CP15 MCR/MRC",
396         [ESR_ELx_EC_CP15_64]            = "CP15 MCRR/MRRC",
397         [ESR_ELx_EC_CP14_MR]            = "CP14 MCR/MRC",
398         [ESR_ELx_EC_CP14_LS]            = "CP14 LDC/STC",
399         [ESR_ELx_EC_FP_ASIMD]           = "ASIMD",
400         [ESR_ELx_EC_CP10_ID]            = "CP10 MRC/VMRS",
401         [ESR_ELx_EC_CP14_64]            = "CP14 MCRR/MRRC",
402         [ESR_ELx_EC_ILL]                = "PSTATE.IL",
403         [ESR_ELx_EC_SVC32]              = "SVC (AArch32)",
404         [ESR_ELx_EC_HVC32]              = "HVC (AArch32)",
405         [ESR_ELx_EC_SMC32]              = "SMC (AArch32)",
406         [ESR_ELx_EC_SVC64]              = "SVC (AArch64)",
407         [ESR_ELx_EC_HVC64]              = "HVC (AArch64)",
408         [ESR_ELx_EC_SMC64]              = "SMC (AArch64)",
409         [ESR_ELx_EC_SYS64]              = "MSR/MRS (AArch64)",
410         [ESR_ELx_EC_IMP_DEF]            = "EL3 IMP DEF",
411         [ESR_ELx_EC_IABT_LOW]           = "IABT (lower EL)",
412         [ESR_ELx_EC_IABT_CUR]           = "IABT (current EL)",
413         [ESR_ELx_EC_PC_ALIGN]           = "PC Alignment",
414         [ESR_ELx_EC_DABT_LOW]           = "DABT (lower EL)",
415         [ESR_ELx_EC_DABT_CUR]           = "DABT (current EL)",
416         [ESR_ELx_EC_SP_ALIGN]           = "SP Alignment",
417         [ESR_ELx_EC_FP_EXC32]           = "FP (AArch32)",
418         [ESR_ELx_EC_FP_EXC64]           = "FP (AArch64)",
419         [ESR_ELx_EC_SERROR]             = "SError",
420         [ESR_ELx_EC_BREAKPT_LOW]        = "Breakpoint (lower EL)",
421         [ESR_ELx_EC_BREAKPT_CUR]        = "Breakpoint (current EL)",
422         [ESR_ELx_EC_SOFTSTP_LOW]        = "Software Step (lower EL)",
423         [ESR_ELx_EC_SOFTSTP_CUR]        = "Software Step (current EL)",
424         [ESR_ELx_EC_WATCHPT_LOW]        = "Watchpoint (lower EL)",
425         [ESR_ELx_EC_WATCHPT_CUR]        = "Watchpoint (current EL)",
426         [ESR_ELx_EC_BKPT32]             = "BKPT (AArch32)",
427         [ESR_ELx_EC_VECTOR32]           = "Vector catch (AArch32)",
428         [ESR_ELx_EC_BRK64]              = "BRK (AArch64)",
429 };
430
431 const char *esr_get_class_string(u32 esr)
432 {
433         return esr_class_str[esr >> ESR_ELx_EC_SHIFT];
434 }
435
436 /*
437  * bad_mode handles the impossible case in the exception vector. This is always
438  * fatal.
439  */
440 asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
441 {
442         console_verbose();
443
444         pr_crit("Bad mode in %s handler detected, code 0x%08x -- %s\n",
445                 handler[reason], esr, esr_get_class_string(esr));
446
447         die("Oops - bad mode", regs, 0);
448         local_irq_disable();
449         panic("bad mode");
450 }
451
452 /*
453  * bad_el0_sync handles unexpected, but potentially recoverable synchronous
454  * exceptions taken from EL0. Unlike bad_mode, this returns.
455  */
456 asmlinkage void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr)
457 {
458         siginfo_t info;
459         void __user *pc = (void __user *)instruction_pointer(regs);
460         console_verbose();
461
462         pr_crit("Bad EL0 synchronous exception detected on CPU%d, code 0x%08x -- %s\n",
463                 smp_processor_id(), esr, esr_get_class_string(esr));
464         __show_regs(regs);
465
466         info.si_signo = SIGILL;
467         info.si_errno = 0;
468         info.si_code  = ILL_ILLOPC;
469         info.si_addr  = pc;
470
471         current->thread.fault_address = 0;
472         current->thread.fault_code = 0;
473
474         force_sig_info(info.si_signo, &info, current);
475 }
476
477 void __pte_error(const char *file, int line, unsigned long val)
478 {
479         pr_crit("%s:%d: bad pte %016lx.\n", file, line, val);
480 }
481
482 void __pmd_error(const char *file, int line, unsigned long val)
483 {
484         pr_crit("%s:%d: bad pmd %016lx.\n", file, line, val);
485 }
486
487 void __pud_error(const char *file, int line, unsigned long val)
488 {
489         pr_crit("%s:%d: bad pud %016lx.\n", file, line, val);
490 }
491
492 void __pgd_error(const char *file, int line, unsigned long val)
493 {
494         pr_crit("%s:%d: bad pgd %016lx.\n", file, line, val);
495 }
496
497 /* GENERIC_BUG traps */
498
499 int is_valid_bugaddr(unsigned long addr)
500 {
501         /*
502          * bug_handler() only called for BRK #BUG_BRK_IMM.
503          * So the answer is trivial -- any spurious instances with no
504          * bug table entry will be rejected by report_bug() and passed
505          * back to the debug-monitors code and handled as a fatal
506          * unexpected debug exception.
507          */
508         return 1;
509 }
510
511 static int bug_handler(struct pt_regs *regs, unsigned int esr)
512 {
513         if (user_mode(regs))
514                 return DBG_HOOK_ERROR;
515
516         switch (report_bug(regs->pc, regs)) {
517         case BUG_TRAP_TYPE_BUG:
518                 die("Oops - BUG", regs, 0);
519                 break;
520
521         case BUG_TRAP_TYPE_WARN:
522                 /* Ideally, report_bug() should backtrace for us... but no. */
523                 dump_backtrace(regs, NULL);
524                 break;
525
526         default:
527                 /* unknown/unrecognised bug trap type */
528                 return DBG_HOOK_ERROR;
529         }
530
531         /* If thread survives, skip over the BUG instruction and continue: */
532         regs->pc += AARCH64_INSN_SIZE;  /* skip BRK and resume */
533         return DBG_HOOK_HANDLED;
534 }
535
536 static struct break_hook bug_break_hook = {
537         .esr_val = 0xf2000000 | BUG_BRK_IMM,
538         .esr_mask = 0xffffffff,
539         .fn = bug_handler,
540 };
541
542 /*
543  * Initial handler for AArch64 BRK exceptions
544  * This handler only used until debug_traps_init().
545  */
546 int __init early_brk64(unsigned long addr, unsigned int esr,
547                 struct pt_regs *regs)
548 {
549         return bug_handler(regs, esr) != DBG_HOOK_HANDLED;
550 }
551
552 /* This registration must happen early, before debug_traps_init(). */
553 void __init trap_init(void)
554 {
555         register_break_hook(&bug_break_hook);
556 }