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/stack_pointer.h>
  42 #include <asm/stacktrace.h>
  43 #include <asm/exception.h>
  44 #include <asm/system_misc.h>
  45 #include <asm/sysreg.h>
  46
  47 static const char *handler[]= {
  48         "Synchronous Abort",
  49         "IRQ",
  50         "FIQ",
  51         "Error"
  52 };
  53
  54 int show_unhandled_signals = 1;
  55
  56 /*
  57  * Dump out the contents of some kernel memory nicely...
  58  */
  59 static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
  60                      unsigned long top)
  61 {
  62         unsigned long first;
  63         mm_segment_t fs;
  64         int i;
  65
  66         /*
  67          * We need to switch to kernel mode so that we can use __get_user
  68          * to safely read from kernel space.
  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 / 8)
  83                                         && p < top; i++, p += 8) {
  84                         if (p >= bottom && p < top) {
  85                                 unsigned long val;
  86
  87                                 if (__get_user(val, (unsigned long *)p) == 0)
  88                                         sprintf(str + i * 17, " %016lx", val);
  89                                 else
  90                                         sprintf(str + i * 17, " ????????????????");
  91                         }
  92                 }
  93                 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
  94         }
  95
  96         set_fs(fs);
  97 }
  98
  99 static void dump_backtrace_entry(unsigned long where)
 100 {
 101         /*
 102          * Note that 'where' can have a physical address, but it's not handled.
 103          */
 104         print_ip_sym(where);
 105 }
 106
 107 static void __dump_instr(const char *lvl, struct pt_regs *regs)
 108 {
 109         unsigned long addr = instruction_pointer(regs);
 110         char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
 111         int i;
 112
 113         for (i = -4; i < 1; i++) {
 114                 unsigned int val, bad;
 115
 116                 bad = __get_user(val, &((u32 *)addr)[i]);
 117
 118                 if (!bad)
 119                         p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
 120                 else {
 121                         p += sprintf(p, "bad PC value");
 122                         break;
 123                 }
 124         }
 125         printk("%sCode: %s\n", lvl, str);
 126 }
 127
 128 static void dump_instr(const char *lvl, struct pt_regs *regs)
 129 {
 130         if (!user_mode(regs)) {
 131                 mm_segment_t fs = get_fs();
 132                 set_fs(KERNEL_DS);
 133                 __dump_instr(lvl, regs);
 134                 set_fs(fs);
 135         } else {
 136                 __dump_instr(lvl, regs);
 137         }
 138 }
 139
 140 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 141 {
 142         struct stackframe frame;
 143         unsigned long irq_stack_ptr;
 144         int skip;
 145
 146         pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
 147
 148         if (!tsk)
 149                 tsk = current;
 150
 151         if (!try_get_task_stack(tsk))
 152                 return;
 153
 154         /*
 155          * Switching between stacks is valid when tracing current and in
 156          * non-preemptible context.
 157          */
 158         if (tsk == current && !preemptible())
 159                 irq_stack_ptr = IRQ_STACK_PTR(smp_processor_id());
 160         else
 161                 irq_stack_ptr = 0;
 162
 163         if (tsk == current) {
 164                 frame.fp = (unsigned long)__builtin_frame_address(0);
 165                 frame.sp = current_stack_pointer;
 166                 frame.pc = (unsigned long)dump_backtrace;
 167         } else {
 168                 /*
 169                  * task blocked in __switch_to
 170                  */
 171                 frame.fp = thread_saved_fp(tsk);
 172                 frame.sp = thread_saved_sp(tsk);
 173                 frame.pc = thread_saved_pc(tsk);
 174         }
 175 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 176         frame.graph = tsk->curr_ret_stack;
 177 #endif
 178
 179         skip = !!regs;
 180         printk("Call trace:\n");
 181         while (1) {
 182                 unsigned long where = frame.pc;
 183                 unsigned long stack;
 184                 int ret;
 185
 186                 /* skip until specified stack frame */
 187                 if (!skip) {
 188                         dump_backtrace_entry(where);
 189                 } else if (frame.fp == regs->regs[29]) {
 190                         skip = 0;
 191                         /*
 192                          * Mostly, this is the case where this function is
 193                          * called in panic/abort. As exception handler's
 194                          * stack frame does not contain the corresponding pc
 195                          * at which an exception has taken place, use regs->pc
 196                          * instead.
 197                          */
 198                         dump_backtrace_entry(regs->pc);
 199                 }
 200                 ret = unwind_frame(tsk, &frame);
 201                 if (ret < 0)
 202                         break;
 203                 stack = frame.sp;
 204                 if (in_exception_text(where)) {
 205                         /*
 206                          * If we switched to the irq_stack before calling this
 207                          * exception handler, then the pt_regs will be on the
 208                          * task stack. The easiest way to tell is if the large
 209                          * pt_regs would overlap with the end of the irq_stack.
 210                          */
 211                         if (stack < irq_stack_ptr &&
 212                             (stack + sizeof(struct pt_regs)) > irq_stack_ptr)
 213                                 stack = IRQ_STACK_TO_TASK_STACK(irq_stack_ptr);
 214
 215                         dump_mem("", "Exception stack", stack,
 216                                  stack + sizeof(struct pt_regs));
 217                 }
 218         }
 219
 220         put_task_stack(tsk);
 221 }
 222
 223 void show_stack(struct task_struct *tsk, unsigned long *sp)
 224 {
 225         dump_backtrace(NULL, tsk);
 226         barrier();
 227 }
 228
 229 #ifdef CONFIG_PREEMPT
 230 #define S_PREEMPT " PREEMPT"
 231 #else
 232 #define S_PREEMPT ""
 233 #endif
 234 #define S_SMP " SMP"
 235
 236 static int __die(const char *str, int err, struct pt_regs *regs)
 237 {
 238         struct task_struct *tsk = current;
 239         static int die_counter;
 240         int ret;
 241
 242         pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
 243                  str, err, ++die_counter);
 244
 245         /* trap and error numbers are mostly meaningless on ARM */
 246         ret = notify_die(DIE_OOPS, str, regs, err, 0, SIGSEGV);
 247         if (ret == NOTIFY_STOP)
 248                 return ret;
 249
 250         print_modules();
 251         __show_regs(regs);
 252         pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
 253                  TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk),
 254                  end_of_stack(tsk));
 255
 256         if (!user_mode(regs)) {
 257                 dump_mem(KERN_EMERG, "Stack: ", regs->sp,
 258                          THREAD_SIZE + (unsigned long)task_stack_page(tsk));
 259                 dump_backtrace(regs, tsk);
 260                 dump_instr(KERN_EMERG, regs);
 261         }
 262
 263         return ret;
 264 }
 265
 266 static DEFINE_RAW_SPINLOCK(die_lock);
 267
 268 /*
 269  * This function is protected against re-entrancy.
 270  */
 271 void die(const char *str, struct pt_regs *regs, int err)
 272 {
 273         int ret;
 274
 275         oops_enter();
 276
 277         raw_spin_lock_irq(&die_lock);
 278         console_verbose();
 279         bust_spinlocks(1);
 280         ret = __die(str, err, regs);
 281
 282         if (regs && kexec_should_crash(current))
 283                 crash_kexec(regs);
 284
 285         bust_spinlocks(0);
 286         add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 287         raw_spin_unlock_irq(&die_lock);
 288         oops_exit();
 289
 290         if (in_interrupt())
 291                 panic("Fatal exception in interrupt");
 292         if (panic_on_oops)
 293                 panic("Fatal exception");
 294         if (ret != NOTIFY_STOP)
 295                 do_exit(SIGSEGV);
 296 }
 297
 298 void arm64_notify_die(const char *str, struct pt_regs *regs,
 299                       struct siginfo *info, int err)
 300 {
 301         if (user_mode(regs)) {
 302                 current->thread.fault_address = 0;
 303                 current->thread.fault_code = err;
 304                 force_sig_info(info->si_signo, info, current);
 305         } else {
 306                 die(str, regs, err);
 307         }
 308 }
 309
 310 static LIST_HEAD(undef_hook);
 311 static DEFINE_RAW_SPINLOCK(undef_lock);
 312
 313 void register_undef_hook(struct undef_hook *hook)
 314 {
 315         unsigned long flags;
 316
 317         raw_spin_lock_irqsave(&undef_lock, flags);
 318         list_add(&hook->node, &undef_hook);
 319         raw_spin_unlock_irqrestore(&undef_lock, flags);
 320 }
 321
 322 void unregister_undef_hook(struct undef_hook *hook)
 323 {
 324         unsigned long flags;
 325
 326         raw_spin_lock_irqsave(&undef_lock, flags);
 327         list_del(&hook->node);
 328         raw_spin_unlock_irqrestore(&undef_lock, flags);
 329 }
 330
 331 static int call_undef_hook(struct pt_regs *regs)
 332 {
 333         struct undef_hook *hook;
 334         unsigned long flags;
 335         u32 instr;
 336         int (*fn)(struct pt_regs *regs, u32 instr) = NULL;
 337         void __user *pc = (void __user *)instruction_pointer(regs);
 338
 339         if (!user_mode(regs))
 340                 return 1;
 341
 342         if (compat_thumb_mode(regs)) {
 343                 /* 16-bit Thumb instruction */
 344                 if (get_user(instr, (u16 __user *)pc))
 345                         goto exit;
 346                 instr = le16_to_cpu(instr);
 347                 if (aarch32_insn_is_wide(instr)) {
 348                         u32 instr2;
 349
 350                         if (get_user(instr2, (u16 __user *)(pc + 2)))
 351                                 goto exit;
 352                         instr2 = le16_to_cpu(instr2);
 353                         instr = (instr << 16) | instr2;
 354                 }
 355         } else {
 356                 /* 32-bit ARM instruction */
 357                 if (get_user(instr, (u32 __user *)pc))
 358                         goto exit;
 359                 instr = le32_to_cpu(instr);
 360         }
 361
 362         raw_spin_lock_irqsave(&undef_lock, flags);
 363         list_for_each_entry(hook, &undef_hook, node)
 364                 if ((instr & hook->instr_mask) == hook->instr_val &&
 365                         (regs->pstate & hook->pstate_mask) == hook->pstate_val)
 366                         fn = hook->fn;
 367
 368         raw_spin_unlock_irqrestore(&undef_lock, flags);
 369 exit:
 370         return fn ? fn(regs, instr) : 1;
 371 }
 372
 373 static void force_signal_inject(int signal, int code, struct pt_regs *regs,
 374                                 unsigned long address)
 375 {
 376         siginfo_t info;
 377         void __user *pc = (void __user *)instruction_pointer(regs);
 378         const char *desc;
 379
 380         switch (signal) {
 381         case SIGILL:
 382                 desc = "undefined instruction";
 383                 break;
 384         case SIGSEGV:
 385                 desc = "illegal memory access";
 386                 break;
 387         default:
 388                 desc = "bad mode";
 389                 break;
 390         }
 391
 392         if (unhandled_signal(current, signal) &&
 393             show_unhandled_signals_ratelimited()) {
 394                 pr_info("%s[%d]: %s: pc=%p\n",
 395                         current->comm, task_pid_nr(current), desc, pc);
 396                 dump_instr(KERN_INFO, regs);
 397         }
 398
 399         info.si_signo = signal;
 400         info.si_errno = 0;
 401         info.si_code  = code;
 402         info.si_addr  = pc;
 403
 404         arm64_notify_die(desc, regs, &info, 0);
 405 }
 406
 407 /*
 408  * Set up process info to signal segmentation fault - called on access error.
 409  */
 410 void arm64_notify_segfault(struct pt_regs *regs, unsigned long addr)
 411 {
 412         int code;
 413
 414         down_read(&current->mm->mmap_sem);
 415         if (find_vma(current->mm, addr) == NULL)
 416                 code = SEGV_MAPERR;
 417         else
 418                 code = SEGV_ACCERR;
 419         up_read(&current->mm->mmap_sem);
 420
 421         force_signal_inject(SIGSEGV, code, regs, addr);
 422 }
 423
 424 asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
 425 {
 426         /* check for AArch32 breakpoint instructions */
 427         if (!aarch32_break_handler(regs))
 428                 return;
 429
 430         if (call_undef_hook(regs) == 0)
 431                 return;
 432
 433         force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
 434 }
 435
 436 int cpu_enable_cache_maint_trap(void *__unused)
 437 {
 438         config_sctlr_el1(SCTLR_EL1_UCI, 0);
 439         return 0;
 440 }
 441
 442 #define __user_cache_maint(insn, address, res)                  \
 443         if (untagged_addr(address) >= user_addr_max()) {        \
 444                 res = -EFAULT;                                  \
 445         } else {                                                \
 446                 uaccess_ttbr0_enable();                         \
 447                 asm volatile (                                  \
 448                         "1:     " insn ", %1\n"                 \
 449                         "       mov     %w0, #0\n"              \
 450                         "2:\n"                                  \
 451                         "       .pushsection .fixup,\"ax\"\n"   \
 452                         "       .align  2\n"                    \
 453                         "3:     mov     %w0, %w2\n"             \
 454                         "       b       2b\n"                   \
 455                         "       .popsection\n"                  \
 456                         _ASM_EXTABLE(1b, 3b)                    \
 457                         : "=r" (res)                            \
 458                         : "r" (address), "i" (-EFAULT));        \
 459                 uaccess_ttbr0_disable();                        \
 460         }
 461
 462 static void user_cache_maint_handler(unsigned int esr, struct pt_regs *regs)
 463 {
 464         unsigned long address;
 465         int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
 466         int crm = (esr & ESR_ELx_SYS64_ISS_CRM_MASK) >> ESR_ELx_SYS64_ISS_CRM_SHIFT;
 467         int ret = 0;
 468
 469         address = (rt == 31) ? 0 : regs->regs[rt];
 470
 471         switch (crm) {
 472         case ESR_ELx_SYS64_ISS_CRM_DC_CVAU:     /* DC CVAU, gets promoted */
 473                 __user_cache_maint("dc civac", address, ret);
 474                 break;
 475         case ESR_ELx_SYS64_ISS_CRM_DC_CVAC:     /* DC CVAC, gets promoted */
 476                 __user_cache_maint("dc civac", address, ret);
 477                 break;
 478         case ESR_ELx_SYS64_ISS_CRM_DC_CIVAC:    /* DC CIVAC */
 479                 __user_cache_maint("dc civac", address, ret);
 480                 break;
 481         case ESR_ELx_SYS64_ISS_CRM_IC_IVAU:     /* IC IVAU */
 482                 __user_cache_maint("ic ivau", address, ret);
 483                 break;
 484         default:
 485                 force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
 486                 return;
 487         }
 488
 489         if (ret)
 490                 arm64_notify_segfault(regs, address);
 491         else
 492                 regs->pc += 4;
 493 }
 494
 495 static void ctr_read_handler(unsigned int esr, struct pt_regs *regs)
 496 {
 497         int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
 498
 499         regs->regs[rt] = arm64_ftr_reg_ctrel0.sys_val;
 500         regs->pc += 4;
 501 }
 502
 503 struct sys64_hook {
 504         unsigned int esr_mask;
 505         unsigned int esr_val;
 506         void (*handler)(unsigned int esr, struct pt_regs *regs);
 507 };
 508
 509 static struct sys64_hook sys64_hooks[] = {
 510         {
 511                 .esr_mask = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_MASK,
 512                 .esr_val = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_VAL,
 513                 .handler = user_cache_maint_handler,
 514         },
 515         {
 516                 /* Trap read access to CTR_EL0 */
 517                 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
 518                 .esr_val = ESR_ELx_SYS64_ISS_SYS_CTR_READ,
 519                 .handler = ctr_read_handler,
 520         },
 521         {},
 522 };
 523
 524 asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
 525 {
 526         struct sys64_hook *hook;
 527
 528         for (hook = sys64_hooks; hook->handler; hook++)
 529                 if ((hook->esr_mask & esr) == hook->esr_val) {
 530                         hook->handler(esr, regs);
 531                         return;
 532                 }
 533
 534         force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
 535 }
 536
 537 long compat_arm_syscall(struct pt_regs *regs);
 538
 539 asmlinkage long do_ni_syscall(struct pt_regs *regs)
 540 {
 541 #ifdef CONFIG_COMPAT
 542         long ret;
 543         if (is_compat_task()) {
 544                 ret = compat_arm_syscall(regs);
 545                 if (ret != -ENOSYS)
 546                         return ret;
 547         }
 548 #endif
 549
 550         if (show_unhandled_signals_ratelimited()) {
 551                 pr_info("%s[%d]: syscall %d\n", current->comm,
 552                         task_pid_nr(current), (int)regs->syscallno);
 553                 dump_instr("", regs);
 554                 if (user_mode(regs))
 555                         __show_regs(regs);
 556         }
 557
 558         return sys_ni_syscall();
 559 }
 560
 561 static const char *esr_class_str[] = {
 562         [0 ... ESR_ELx_EC_MAX]          = "UNRECOGNIZED EC",
 563         [ESR_ELx_EC_UNKNOWN]            = "Unknown/Uncategorized",
 564         [ESR_ELx_EC_WFx]                = "WFI/WFE",
 565         [ESR_ELx_EC_CP15_32]            = "CP15 MCR/MRC",
 566         [ESR_ELx_EC_CP15_64]            = "CP15 MCRR/MRRC",
 567         [ESR_ELx_EC_CP14_MR]            = "CP14 MCR/MRC",
 568         [ESR_ELx_EC_CP14_LS]            = "CP14 LDC/STC",
 569         [ESR_ELx_EC_FP_ASIMD]           = "ASIMD",
 570         [ESR_ELx_EC_CP10_ID]            = "CP10 MRC/VMRS",
 571         [ESR_ELx_EC_CP14_64]            = "CP14 MCRR/MRRC",
 572         [ESR_ELx_EC_ILL]                = "PSTATE.IL",
 573         [ESR_ELx_EC_SVC32]              = "SVC (AArch32)",
 574         [ESR_ELx_EC_HVC32]              = "HVC (AArch32)",
 575         [ESR_ELx_EC_SMC32]              = "SMC (AArch32)",
 576         [ESR_ELx_EC_SVC64]              = "SVC (AArch64)",
 577         [ESR_ELx_EC_HVC64]              = "HVC (AArch64)",
 578         [ESR_ELx_EC_SMC64]              = "SMC (AArch64)",
 579         [ESR_ELx_EC_SYS64]              = "MSR/MRS (AArch64)",
 580         [ESR_ELx_EC_IMP_DEF]            = "EL3 IMP DEF",
 581         [ESR_ELx_EC_IABT_LOW]           = "IABT (lower EL)",
 582         [ESR_ELx_EC_IABT_CUR]           = "IABT (current EL)",
 583         [ESR_ELx_EC_PC_ALIGN]           = "PC Alignment",
 584         [ESR_ELx_EC_DABT_LOW]           = "DABT (lower EL)",
 585         [ESR_ELx_EC_DABT_CUR]           = "DABT (current EL)",
 586         [ESR_ELx_EC_SP_ALIGN]           = "SP Alignment",
 587         [ESR_ELx_EC_FP_EXC32]           = "FP (AArch32)",
 588         [ESR_ELx_EC_FP_EXC64]           = "FP (AArch64)",
 589         [ESR_ELx_EC_SERROR]             = "SError",
 590         [ESR_ELx_EC_BREAKPT_LOW]        = "Breakpoint (lower EL)",
 591         [ESR_ELx_EC_BREAKPT_CUR]        = "Breakpoint (current EL)",
 592         [ESR_ELx_EC_SOFTSTP_LOW]        = "Software Step (lower EL)",
 593         [ESR_ELx_EC_SOFTSTP_CUR]        = "Software Step (current EL)",
 594         [ESR_ELx_EC_WATCHPT_LOW]        = "Watchpoint (lower EL)",
 595         [ESR_ELx_EC_WATCHPT_CUR]        = "Watchpoint (current EL)",
 596         [ESR_ELx_EC_BKPT32]             = "BKPT (AArch32)",
 597         [ESR_ELx_EC_VECTOR32]           = "Vector catch (AArch32)",
 598         [ESR_ELx_EC_BRK64]              = "BRK (AArch64)",
 599 };
 600
 601 const char *esr_get_class_string(u32 esr)
 602 {
 603         return esr_class_str[ESR_ELx_EC(esr)];
 604 }
 605
 606 /*
 607  * bad_mode handles the impossible case in the exception vector. This is always
 608  * fatal.
 609  */
 610 asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
 611 {
 612         console_verbose();
 613
 614         pr_crit("Bad mode in %s handler detected on CPU%d, code 0x%08x -- %s\n",
 615                 handler[reason], smp_processor_id(), esr,
 616                 esr_get_class_string(esr));
 617
 618         die("Oops - bad mode", regs, 0);
 619         local_irq_disable();
 620         panic("bad mode");
 621 }
 622
 623 /*
 624  * bad_el0_sync handles unexpected, but potentially recoverable synchronous
 625  * exceptions taken from EL0. Unlike bad_mode, this returns.
 626  */
 627 asmlinkage void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr)
 628 {
 629         siginfo_t info;
 630         void __user *pc = (void __user *)instruction_pointer(regs);
 631         console_verbose();
 632
 633         pr_crit("Bad EL0 synchronous exception detected on CPU%d, code 0x%08x -- %s\n",
 634                 smp_processor_id(), esr, esr_get_class_string(esr));
 635         __show_regs(regs);
 636
 637         info.si_signo = SIGILL;
 638         info.si_errno = 0;
 639         info.si_code  = ILL_ILLOPC;
 640         info.si_addr  = pc;
 641
 642         current->thread.fault_address = 0;
 643         current->thread.fault_code = 0;
 644
 645         force_sig_info(info.si_signo, &info, current);
 646 }
 647
 648 void __pte_error(const char *file, int line, unsigned long val)
 649 {
 650         pr_err("%s:%d: bad pte %016lx.\n", file, line, val);
 651 }
 652
 653 void __pmd_error(const char *file, int line, unsigned long val)
 654 {
 655         pr_err("%s:%d: bad pmd %016lx.\n", file, line, val);
 656 }
 657
 658 void __pud_error(const char *file, int line, unsigned long val)
 659 {
 660         pr_err("%s:%d: bad pud %016lx.\n", file, line, val);
 661 }
 662
 663 void __pgd_error(const char *file, int line, unsigned long val)
 664 {
 665         pr_err("%s:%d: bad pgd %016lx.\n", file, line, val);
 666 }
 667
 668 /* GENERIC_BUG traps */
 669
 670 int is_valid_bugaddr(unsigned long addr)
 671 {
 672         /*
 673          * bug_handler() only called for BRK #BUG_BRK_IMM.
 674          * So the answer is trivial -- any spurious instances with no
 675          * bug table entry will be rejected by report_bug() and passed
 676          * back to the debug-monitors code and handled as a fatal
 677          * unexpected debug exception.
 678          */
 679         return 1;
 680 }
 681
 682 static int bug_handler(struct pt_regs *regs, unsigned int esr)
 683 {
 684         if (user_mode(regs))
 685                 return DBG_HOOK_ERROR;
 686
 687         switch (report_bug(regs->pc, regs)) {
 688         case BUG_TRAP_TYPE_BUG:
 689                 die("Oops - BUG", regs, 0);
 690                 break;
 691
 692         case BUG_TRAP_TYPE_WARN:
 693                 /* Ideally, report_bug() should backtrace for us... but no. */
 694                 dump_backtrace(regs, NULL);
 695                 break;
 696
 697         default:
 698                 /* unknown/unrecognised bug trap type */
 699                 return DBG_HOOK_ERROR;
 700         }
 701
 702         /* If thread survives, skip over the BUG instruction and continue: */
 703         regs->pc += AARCH64_INSN_SIZE;  /* skip BRK and resume */
 704         return DBG_HOOK_HANDLED;
 705 }
 706
 707 static struct break_hook bug_break_hook = {
 708         .esr_val = 0xf2000000 | BUG_BRK_IMM,
 709         .esr_mask = 0xffffffff,
 710         .fn = bug_handler,
 711 };
 712
 713 /*
 714  * Initial handler for AArch64 BRK exceptions
 715  * This handler only used until debug_traps_init().
 716  */
 717 int __init early_brk64(unsigned long addr, unsigned int esr,
 718                 struct pt_regs *regs)
 719 {
 720         return bug_handler(regs, esr) != DBG_HOOK_HANDLED;
 721 }
 722
 723 /* This registration must happen early, before debug_traps_init(). */
 724 void __init trap_init(void)
 725 {
 726         register_break_hook(&bug_break_hook);
 727 }