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/cpufeature.h>
  38 #include <asm/debug-monitors.h>
  39 #include <asm/esr.h>
  40 #include <asm/insn.h>
  41 #include <asm/traps.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 = 0;
  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         /*
 152          * Switching between stacks is valid when tracing current and in
 153          * non-preemptible context.
 154          */
 155         if (tsk == current && !preemptible())
 156                 irq_stack_ptr = IRQ_STACK_PTR(smp_processor_id());
 157         else
 158                 irq_stack_ptr = 0;
 159
 160         if (tsk == current) {
 161                 frame.fp = (unsigned long)__builtin_frame_address(0);
 162                 frame.sp = current_stack_pointer;
 163                 frame.pc = (unsigned long)dump_backtrace;
 164         } else {
 165                 /*
 166                  * task blocked in __switch_to
 167                  */
 168                 frame.fp = thread_saved_fp(tsk);
 169                 frame.sp = thread_saved_sp(tsk);
 170                 frame.pc = thread_saved_pc(tsk);
 171         }
 172 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 173         frame.graph = tsk->curr_ret_stack;
 174 #endif
 175
 176         skip = !!regs;
 177         printk("Call trace:\n");
 178         while (1) {
 179                 unsigned long where = frame.pc;
 180                 unsigned long stack;
 181                 int ret;
 182
 183                 /* skip until specified stack frame */
 184                 if (!skip) {
 185                         dump_backtrace_entry(where);
 186                 } else if (frame.fp == regs->regs[29]) {
 187                         skip = 0;
 188                         /*
 189                          * Mostly, this is the case where this function is
 190                          * called in panic/abort. As exception handler's
 191                          * stack frame does not contain the corresponding pc
 192                          * at which an exception has taken place, use regs->pc
 193                          * instead.
 194                          */
 195                         dump_backtrace_entry(regs->pc);
 196                 }
 197                 ret = unwind_frame(tsk, &frame);
 198                 if (ret < 0)
 199                         break;
 200                 stack = frame.sp;
 201                 if (in_exception_text(where)) {
 202                         /*
 203                          * If we switched to the irq_stack before calling this
 204                          * exception handler, then the pt_regs will be on the
 205                          * task stack. The easiest way to tell is if the large
 206                          * pt_regs would overlap with the end of the irq_stack.
 207                          */
 208                         if (stack < irq_stack_ptr &&
 209                             (stack + sizeof(struct pt_regs)) > irq_stack_ptr)
 210                                 stack = IRQ_STACK_TO_TASK_STACK(irq_stack_ptr);
 211
 212                         dump_mem("", "Exception stack", stack,
 213                                  stack + sizeof(struct pt_regs));
 214                 }
 215         }
 216 }
 217
 218 void show_stack(struct task_struct *tsk, unsigned long *sp)
 219 {
 220         dump_backtrace(NULL, tsk);
 221         barrier();
 222 }
 223
 224 #ifdef CONFIG_PREEMPT
 225 #define S_PREEMPT " PREEMPT"
 226 #else
 227 #define S_PREEMPT ""
 228 #endif
 229 #define S_SMP " SMP"
 230
 231 static int __die(const char *str, int err, struct thread_info *thread,
 232                  struct pt_regs *regs)
 233 {
 234         struct task_struct *tsk = thread->task;
 235         static int die_counter;
 236         int ret;
 237
 238         pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
 239                  str, err, ++die_counter);
 240
 241         /* trap and error numbers are mostly meaningless on ARM */
 242         ret = notify_die(DIE_OOPS, str, regs, err, 0, SIGSEGV);
 243         if (ret == NOTIFY_STOP)
 244                 return ret;
 245
 246         print_modules();
 247         __show_regs(regs);
 248         pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
 249                  TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1);
 250
 251         if (!user_mode(regs)) {
 252                 dump_mem(KERN_EMERG, "Stack: ", regs->sp,
 253                          THREAD_SIZE + (unsigned long)task_stack_page(tsk));
 254                 dump_backtrace(regs, tsk);
 255                 dump_instr(KERN_EMERG, regs);
 256         }
 257
 258         return ret;
 259 }
 260
 261 static DEFINE_RAW_SPINLOCK(die_lock);
 262
 263 /*
 264  * This function is protected against re-entrancy.
 265  */
 266 void die(const char *str, struct pt_regs *regs, int err)
 267 {
 268         struct thread_info *thread = current_thread_info();
 269         int ret;
 270         unsigned long flags;
 271
 272         raw_spin_lock_irqsave(&die_lock, flags);
 273
 274         oops_enter();
 275
 276         console_verbose();
 277         bust_spinlocks(1);
 278         ret = __die(str, err, thread, regs);
 279
 280         if (regs && kexec_should_crash(thread->task))
 281                 crash_kexec(regs);
 282
 283         bust_spinlocks(0);
 284         add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 285         oops_exit();
 286
 287         if (in_interrupt())
 288                 panic("Fatal exception in interrupt");
 289         if (panic_on_oops)
 290                 panic("Fatal exception");
 291
 292         raw_spin_unlock_irqrestore(&die_lock, flags);
 293
 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 void cpu_enable_cache_maint_trap(const struct arm64_cpu_capabilities *__unused)
 437 {
 438         config_sctlr_el1(SCTLR_EL1_UCI, 0);
 439 }
 440
 441 #define __user_cache_maint(insn, address, res)                  \
 442         if (address >= user_addr_max())                         \
 443                 res = -EFAULT;                                  \
 444         else                                                    \
 445                 asm volatile (                                  \
 446                         "1:     " insn ", %1\n"                 \
 447                         "       mov     %w0, #0\n"              \
 448                         "2:\n"                                  \
 449                         "       .pushsection .fixup,\"ax\"\n"   \
 450                         "       .align  2\n"                    \
 451                         "3:     mov     %w0, %w2\n"             \
 452                         "       b       2b\n"                   \
 453                         "       .popsection\n"                  \
 454                         _ASM_EXTABLE(1b, 3b)                    \
 455                         : "=r" (res)                            \
 456                         : "r" (address), "i" (-EFAULT) )
 457
 458 static void user_cache_maint_handler(unsigned int esr, struct pt_regs *regs)
 459 {
 460         unsigned long address;
 461         int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
 462         int crm = (esr & ESR_ELx_SYS64_ISS_CRM_MASK) >> ESR_ELx_SYS64_ISS_CRM_SHIFT;
 463         int ret = 0;
 464
 465         address = (rt == 31) ? 0 : untagged_addr(regs->regs[rt]);
 466
 467         switch (crm) {
 468         case ESR_ELx_SYS64_ISS_CRM_DC_CVAU:     /* DC CVAU, gets promoted */
 469                 __user_cache_maint("dc civac", address, ret);
 470                 break;
 471         case ESR_ELx_SYS64_ISS_CRM_DC_CVAC:     /* DC CVAC, gets promoted */
 472                 __user_cache_maint("dc civac", address, ret);
 473                 break;
 474         case ESR_ELx_SYS64_ISS_CRM_DC_CIVAC:    /* DC CIVAC */
 475                 __user_cache_maint("dc civac", address, ret);
 476                 break;
 477         case ESR_ELx_SYS64_ISS_CRM_IC_IVAU:     /* IC IVAU */
 478                 __user_cache_maint("ic ivau", address, ret);
 479                 break;
 480         default:
 481                 force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
 482                 return;
 483         }
 484
 485         if (ret)
 486                 arm64_notify_segfault(regs, address);
 487         else
 488                 regs->pc += 4;
 489 }
 490
 491 static void ctr_read_handler(unsigned int esr, struct pt_regs *regs)
 492 {
 493         int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
 494
 495         regs->regs[rt] = arm64_ftr_reg_ctrel0.sys_val;
 496         regs->pc += 4;
 497 }
 498
 499 struct sys64_hook {
 500         unsigned int esr_mask;
 501         unsigned int esr_val;
 502         void (*handler)(unsigned int esr, struct pt_regs *regs);
 503 };
 504
 505 static struct sys64_hook sys64_hooks[] = {
 506         {
 507                 .esr_mask = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_MASK,
 508                 .esr_val = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_VAL,
 509                 .handler = user_cache_maint_handler,
 510         },
 511         {
 512                 /* Trap read access to CTR_EL0 */
 513                 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
 514                 .esr_val = ESR_ELx_SYS64_ISS_SYS_CTR_READ,
 515                 .handler = ctr_read_handler,
 516         },
 517         {},
 518 };
 519
 520 asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
 521 {
 522         struct sys64_hook *hook;
 523
 524         for (hook = sys64_hooks; hook->handler; hook++)
 525                 if ((hook->esr_mask & esr) == hook->esr_val) {
 526                         hook->handler(esr, regs);
 527                         return;
 528                 }
 529
 530         force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
 531 }
 532
 533 long compat_arm_syscall(struct pt_regs *regs);
 534
 535 asmlinkage long do_ni_syscall(struct pt_regs *regs)
 536 {
 537 #ifdef CONFIG_COMPAT
 538         long ret;
 539         if (is_compat_task()) {
 540                 ret = compat_arm_syscall(regs);
 541                 if (ret != -ENOSYS)
 542                         return ret;
 543         }
 544 #endif
 545
 546         return sys_ni_syscall();
 547 }
 548
 549 static const char *esr_class_str[] = {
 550         [0 ... ESR_ELx_EC_MAX]          = "UNRECOGNIZED EC",
 551         [ESR_ELx_EC_UNKNOWN]            = "Unknown/Uncategorized",
 552         [ESR_ELx_EC_WFx]                = "WFI/WFE",
 553         [ESR_ELx_EC_CP15_32]            = "CP15 MCR/MRC",
 554         [ESR_ELx_EC_CP15_64]            = "CP15 MCRR/MRRC",
 555         [ESR_ELx_EC_CP14_MR]            = "CP14 MCR/MRC",
 556         [ESR_ELx_EC_CP14_LS]            = "CP14 LDC/STC",
 557         [ESR_ELx_EC_FP_ASIMD]           = "ASIMD",
 558         [ESR_ELx_EC_CP10_ID]            = "CP10 MRC/VMRS",
 559         [ESR_ELx_EC_CP14_64]            = "CP14 MCRR/MRRC",
 560         [ESR_ELx_EC_ILL]                = "PSTATE.IL",
 561         [ESR_ELx_EC_SVC32]              = "SVC (AArch32)",
 562         [ESR_ELx_EC_HVC32]              = "HVC (AArch32)",
 563         [ESR_ELx_EC_SMC32]              = "SMC (AArch32)",
 564         [ESR_ELx_EC_SVC64]              = "SVC (AArch64)",
 565         [ESR_ELx_EC_HVC64]              = "HVC (AArch64)",
 566         [ESR_ELx_EC_SMC64]              = "SMC (AArch64)",
 567         [ESR_ELx_EC_SYS64]              = "MSR/MRS (AArch64)",
 568         [ESR_ELx_EC_IMP_DEF]            = "EL3 IMP DEF",
 569         [ESR_ELx_EC_IABT_LOW]           = "IABT (lower EL)",
 570         [ESR_ELx_EC_IABT_CUR]           = "IABT (current EL)",
 571         [ESR_ELx_EC_PC_ALIGN]           = "PC Alignment",
 572         [ESR_ELx_EC_DABT_LOW]           = "DABT (lower EL)",
 573         [ESR_ELx_EC_DABT_CUR]           = "DABT (current EL)",
 574         [ESR_ELx_EC_SP_ALIGN]           = "SP Alignment",
 575         [ESR_ELx_EC_FP_EXC32]           = "FP (AArch32)",
 576         [ESR_ELx_EC_FP_EXC64]           = "FP (AArch64)",
 577         [ESR_ELx_EC_SERROR]             = "SError",
 578         [ESR_ELx_EC_BREAKPT_LOW]        = "Breakpoint (lower EL)",
 579         [ESR_ELx_EC_BREAKPT_CUR]        = "Breakpoint (current EL)",
 580         [ESR_ELx_EC_SOFTSTP_LOW]        = "Software Step (lower EL)",
 581         [ESR_ELx_EC_SOFTSTP_CUR]        = "Software Step (current EL)",
 582         [ESR_ELx_EC_WATCHPT_LOW]        = "Watchpoint (lower EL)",
 583         [ESR_ELx_EC_WATCHPT_CUR]        = "Watchpoint (current EL)",
 584         [ESR_ELx_EC_BKPT32]             = "BKPT (AArch32)",
 585         [ESR_ELx_EC_VECTOR32]           = "Vector catch (AArch32)",
 586         [ESR_ELx_EC_BRK64]              = "BRK (AArch64)",
 587 };
 588
 589 const char *esr_get_class_string(u32 esr)
 590 {
 591         return esr_class_str[ESR_ELx_EC(esr)];
 592 }
 593
 594 /*
 595  * bad_mode handles the impossible case in the exception vector. This is always
 596  * fatal.
 597  */
 598 asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
 599 {
 600         console_verbose();
 601
 602         pr_crit("Bad mode in %s handler detected on CPU%d, code 0x%08x -- %s\n",
 603                 handler[reason], smp_processor_id(), esr,
 604                 esr_get_class_string(esr));
 605
 606         local_irq_disable();
 607         panic("bad mode");
 608 }
 609
 610 /*
 611  * bad_el0_sync handles unexpected, but potentially recoverable synchronous
 612  * exceptions taken from EL0. Unlike bad_mode, this returns.
 613  */
 614 asmlinkage void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr)
 615 {
 616         siginfo_t info;
 617         void __user *pc = (void __user *)instruction_pointer(regs);
 618         console_verbose();
 619
 620         pr_crit("Bad EL0 synchronous exception detected on CPU%d, code 0x%08x -- %s\n",
 621                 smp_processor_id(), esr, esr_get_class_string(esr));
 622         __show_regs(regs);
 623
 624         info.si_signo = SIGILL;
 625         info.si_errno = 0;
 626         info.si_code  = ILL_ILLOPC;
 627         info.si_addr  = pc;
 628
 629         current->thread.fault_address = 0;
 630         current->thread.fault_code = 0;
 631
 632         force_sig_info(info.si_signo, &info, current);
 633 }
 634
 635 void __pte_error(const char *file, int line, unsigned long val)
 636 {
 637         pr_err("%s:%d: bad pte %016lx.\n", file, line, val);
 638 }
 639
 640 void __pmd_error(const char *file, int line, unsigned long val)
 641 {
 642         pr_err("%s:%d: bad pmd %016lx.\n", file, line, val);
 643 }
 644
 645 void __pud_error(const char *file, int line, unsigned long val)
 646 {
 647         pr_err("%s:%d: bad pud %016lx.\n", file, line, val);
 648 }
 649
 650 void __pgd_error(const char *file, int line, unsigned long val)
 651 {
 652         pr_err("%s:%d: bad pgd %016lx.\n", file, line, val);
 653 }
 654
 655 /* GENERIC_BUG traps */
 656
 657 int is_valid_bugaddr(unsigned long addr)
 658 {
 659         /*
 660          * bug_handler() only called for BRK #BUG_BRK_IMM.
 661          * So the answer is trivial -- any spurious instances with no
 662          * bug table entry will be rejected by report_bug() and passed
 663          * back to the debug-monitors code and handled as a fatal
 664          * unexpected debug exception.
 665          */
 666         return 1;
 667 }
 668
 669 static int bug_handler(struct pt_regs *regs, unsigned int esr)
 670 {
 671         if (user_mode(regs))
 672                 return DBG_HOOK_ERROR;
 673
 674         switch (report_bug(regs->pc, regs)) {
 675         case BUG_TRAP_TYPE_BUG:
 676                 die("Oops - BUG", regs, 0);
 677                 break;
 678
 679         case BUG_TRAP_TYPE_WARN:
 680                 /* Ideally, report_bug() should backtrace for us... but no. */
 681                 dump_backtrace(regs, NULL);
 682                 break;
 683
 684         default:
 685                 /* unknown/unrecognised bug trap type */
 686                 return DBG_HOOK_ERROR;
 687         }
 688
 689         /* If thread survives, skip over the BUG instruction and continue: */
 690         regs->pc += AARCH64_INSN_SIZE;  /* skip BRK and resume */
 691         return DBG_HOOK_HANDLED;
 692 }
 693
 694 static struct break_hook bug_break_hook = {
 695         .esr_val = 0xf2000000 | BUG_BRK_IMM,
 696         .esr_mask = 0xffffffff,
 697         .fn = bug_handler,
 698 };
 699
 700 /*
 701  * Initial handler for AArch64 BRK exceptions
 702  * This handler only used until debug_traps_init().
 703  */
 704 int __init early_brk64(unsigned long addr, unsigned int esr,
 705                 struct pt_regs *regs)
 706 {
 707         return bug_handler(regs, esr) != DBG_HOOK_HANDLED;
 708 }
 709
 710 /* This registration must happen early, before debug_traps_init(). */
 711 void __init trap_init(void)
 712 {
 713         register_break_hook(&bug_break_hook);
 714 }