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/signal.h>
  33 #include <linux/sched/debug.h>
  34 #include <linux/sched/task_stack.h>
  35 #include <linux/syscalls.h>
  36 #include <linux/mm_types.h>
  37
  38 #include <asm/atomic.h>
  39 #include <asm/bug.h>
  40 #include <asm/debug-monitors.h>
  41 #include <asm/esr.h>
  42 #include <asm/insn.h>
  43 #include <asm/traps.h>
  44 #include <asm/stack_pointer.h>
  45 #include <asm/stacktrace.h>
  46 #include <asm/exception.h>
  47 #include <asm/system_misc.h>
  48 #include <asm/sysreg.h>
  49
  50 static const char *handler[]= {
  51         "Synchronous Abort",
  52         "IRQ",
  53         "FIQ",
  54         "Error"
  55 };
  56
  57 int show_unhandled_signals = 1;
  58
  59 /*
  60  * Dump out the contents of some kernel memory nicely...
  61  */
  62 static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
  63                      unsigned long top)
  64 {
  65         unsigned long first;
  66         mm_segment_t fs;
  67         int i;
  68
  69         /*
  70          * We need to switch to kernel mode so that we can use __get_user
  71          * to safely read from kernel space.
  72          */
  73         fs = get_fs();
  74         set_fs(KERNEL_DS);
  75
  76         printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top);
  77
  78         for (first = bottom & ~31; first < top; first += 32) {
  79                 unsigned long p;
  80                 char str[sizeof(" 12345678") * 8 + 1];
  81
  82                 memset(str, ' ', sizeof(str));
  83                 str[sizeof(str) - 1] = '\0';
  84
  85                 for (p = first, i = 0; i < (32 / 8)
  86                                         && p < top; i++, p += 8) {
  87                         if (p >= bottom && p < top) {
  88                                 unsigned long val;
  89
  90                                 if (__get_user(val, (unsigned long *)p) == 0)
  91                                         sprintf(str + i * 17, " %016lx", val);
  92                                 else
  93                                         sprintf(str + i * 17, " ????????????????");
  94                         }
  95                 }
  96                 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
  97         }
  98
  99         set_fs(fs);
 100 }
 101
 102 static void dump_backtrace_entry(unsigned long where)
 103 {
 104         /*
 105          * Note that 'where' can have a physical address, but it's not handled.
 106          */
 107         print_ip_sym(where);
 108 }
 109
 110 static void __dump_instr(const char *lvl, struct pt_regs *regs)
 111 {
 112         unsigned long addr = instruction_pointer(regs);
 113         char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
 114         int i;
 115
 116         for (i = -4; i < 1; i++) {
 117                 unsigned int val, bad;
 118
 119                 bad = __get_user(val, &((u32 *)addr)[i]);
 120
 121                 if (!bad)
 122                         p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
 123                 else {
 124                         p += sprintf(p, "bad PC value");
 125                         break;
 126                 }
 127         }
 128         printk("%sCode: %s\n", lvl, str);
 129 }
 130
 131 static void dump_instr(const char *lvl, struct pt_regs *regs)
 132 {
 133         if (!user_mode(regs)) {
 134                 mm_segment_t fs = get_fs();
 135                 set_fs(KERNEL_DS);
 136                 __dump_instr(lvl, regs);
 137                 set_fs(fs);
 138         } else {
 139                 __dump_instr(lvl, regs);
 140         }
 141 }
 142
 143 void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 144 {
 145         struct stackframe frame;
 146         unsigned long irq_stack_ptr;
 147         int skip;
 148
 149         pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
 150
 151         if (!tsk)
 152                 tsk = current;
 153
 154         if (!try_get_task_stack(tsk))
 155                 return;
 156
 157         /*
 158          * Switching between stacks is valid when tracing current and in
 159          * non-preemptible context.
 160          */
 161         if (tsk == current && !preemptible())
 162                 irq_stack_ptr = IRQ_STACK_PTR(smp_processor_id());
 163         else
 164                 irq_stack_ptr = 0;
 165
 166         if (tsk == current) {
 167                 frame.fp = (unsigned long)__builtin_frame_address(0);
 168                 frame.sp = current_stack_pointer;
 169                 frame.pc = (unsigned long)dump_backtrace;
 170         } else {
 171                 /*
 172                  * task blocked in __switch_to
 173                  */
 174                 frame.fp = thread_saved_fp(tsk);
 175                 frame.sp = thread_saved_sp(tsk);
 176                 frame.pc = thread_saved_pc(tsk);
 177         }
 178 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 179         frame.graph = tsk->curr_ret_stack;
 180 #endif
 181
 182         skip = !!regs;
 183         printk("Call trace:\n");
 184         while (1) {
 185                 unsigned long where = frame.pc;
 186                 unsigned long stack;
 187                 int ret;
 188
 189                 /* skip until specified stack frame */
 190                 if (!skip) {
 191                         dump_backtrace_entry(where);
 192                 } else if (frame.fp == regs->regs[29]) {
 193                         skip = 0;
 194                         /*
 195                          * Mostly, this is the case where this function is
 196                          * called in panic/abort. As exception handler's
 197                          * stack frame does not contain the corresponding pc
 198                          * at which an exception has taken place, use regs->pc
 199                          * instead.
 200                          */
 201                         dump_backtrace_entry(regs->pc);
 202                 }
 203                 ret = unwind_frame(tsk, &frame);
 204                 if (ret < 0)
 205                         break;
 206                 stack = frame.sp;
 207                 if (in_exception_text(where)) {
 208                         /*
 209                          * If we switched to the irq_stack before calling this
 210                          * exception handler, then the pt_regs will be on the
 211                          * task stack. The easiest way to tell is if the large
 212                          * pt_regs would overlap with the end of the irq_stack.
 213                          */
 214                         if (stack < irq_stack_ptr &&
 215                             (stack + sizeof(struct pt_regs)) > irq_stack_ptr)
 216                                 stack = IRQ_STACK_TO_TASK_STACK(irq_stack_ptr);
 217
 218                         dump_mem("", "Exception stack", stack,
 219                                  stack + sizeof(struct pt_regs));
 220                 }
 221         }
 222
 223         put_task_stack(tsk);
 224 }
 225
 226 void show_stack(struct task_struct *tsk, unsigned long *sp)
 227 {
 228         dump_backtrace(NULL, tsk);
 229         barrier();
 230 }
 231
 232 #ifdef CONFIG_PREEMPT
 233 #define S_PREEMPT " PREEMPT"
 234 #else
 235 #define S_PREEMPT ""
 236 #endif
 237 #define S_SMP " SMP"
 238
 239 static int __die(const char *str, int err, struct pt_regs *regs)
 240 {
 241         struct task_struct *tsk = current;
 242         static int die_counter;
 243         int ret;
 244
 245         pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
 246                  str, err, ++die_counter);
 247
 248         /* trap and error numbers are mostly meaningless on ARM */
 249         ret = notify_die(DIE_OOPS, str, regs, err, 0, SIGSEGV);
 250         if (ret == NOTIFY_STOP)
 251                 return ret;
 252
 253         print_modules();
 254         __show_regs(regs);
 255         pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
 256                  TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk),
 257                  end_of_stack(tsk));
 258
 259         if (!user_mode(regs)) {
 260                 dump_mem(KERN_EMERG, "Stack: ", regs->sp,
 261                          THREAD_SIZE + (unsigned long)task_stack_page(tsk));
 262                 dump_backtrace(regs, tsk);
 263                 dump_instr(KERN_EMERG, regs);
 264         }
 265
 266         return ret;
 267 }
 268
 269 static DEFINE_RAW_SPINLOCK(die_lock);
 270
 271 /*
 272  * This function is protected against re-entrancy.
 273  */
 274 void die(const char *str, struct pt_regs *regs, int err)
 275 {
 276         int ret;
 277         unsigned long flags;
 278
 279         raw_spin_lock_irqsave(&die_lock, flags);
 280
 281         oops_enter();
 282
 283         console_verbose();
 284         bust_spinlocks(1);
 285         ret = __die(str, err, regs);
 286
 287         if (regs && kexec_should_crash(current))
 288                 crash_kexec(regs);
 289
 290         bust_spinlocks(0);
 291         add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 292         oops_exit();
 293
 294         if (in_interrupt())
 295                 panic("Fatal exception in interrupt");
 296         if (panic_on_oops)
 297                 panic("Fatal exception");
 298
 299         raw_spin_unlock_irqrestore(&die_lock, flags);
 300
 301         if (ret != NOTIFY_STOP)
 302                 do_exit(SIGSEGV);
 303 }
 304
 305 void arm64_notify_die(const char *str, struct pt_regs *regs,
 306                       struct siginfo *info, int err)
 307 {
 308         if (user_mode(regs)) {
 309                 current->thread.fault_address = 0;
 310                 current->thread.fault_code = err;
 311                 force_sig_info(info->si_signo, info, current);
 312         } else {
 313                 die(str, regs, err);
 314         }
 315 }
 316
 317 static LIST_HEAD(undef_hook);
 318 static DEFINE_RAW_SPINLOCK(undef_lock);
 319
 320 void register_undef_hook(struct undef_hook *hook)
 321 {
 322         unsigned long flags;
 323
 324         raw_spin_lock_irqsave(&undef_lock, flags);
 325         list_add(&hook->node, &undef_hook);
 326         raw_spin_unlock_irqrestore(&undef_lock, flags);
 327 }
 328
 329 void unregister_undef_hook(struct undef_hook *hook)
 330 {
 331         unsigned long flags;
 332
 333         raw_spin_lock_irqsave(&undef_lock, flags);
 334         list_del(&hook->node);
 335         raw_spin_unlock_irqrestore(&undef_lock, flags);
 336 }
 337
 338 static int call_undef_hook(struct pt_regs *regs)
 339 {
 340         struct undef_hook *hook;
 341         unsigned long flags;
 342         u32 instr;
 343         int (*fn)(struct pt_regs *regs, u32 instr) = NULL;
 344         void __user *pc = (void __user *)instruction_pointer(regs);
 345
 346         if (!user_mode(regs))
 347                 return 1;
 348
 349         if (compat_thumb_mode(regs)) {
 350                 /* 16-bit Thumb instruction */
 351                 __le16 instr_le;
 352                 if (get_user(instr_le, (__le16 __user *)pc))
 353                         goto exit;
 354                 instr = le16_to_cpu(instr_le);
 355                 if (aarch32_insn_is_wide(instr)) {
 356                         u32 instr2;
 357
 358                         if (get_user(instr_le, (__le16 __user *)(pc + 2)))
 359                                 goto exit;
 360                         instr2 = le16_to_cpu(instr_le);
 361                         instr = (instr << 16) | instr2;
 362                 }
 363         } else {
 364                 /* 32-bit ARM instruction */
 365                 __le32 instr_le;
 366                 if (get_user(instr_le, (__le32 __user *)pc))
 367                         goto exit;
 368                 instr = le32_to_cpu(instr_le);
 369         }
 370
 371         raw_spin_lock_irqsave(&undef_lock, flags);
 372         list_for_each_entry(hook, &undef_hook, node)
 373                 if ((instr & hook->instr_mask) == hook->instr_val &&
 374                         (regs->pstate & hook->pstate_mask) == hook->pstate_val)
 375                         fn = hook->fn;
 376
 377         raw_spin_unlock_irqrestore(&undef_lock, flags);
 378 exit:
 379         return fn ? fn(regs, instr) : 1;
 380 }
 381
 382 static void force_signal_inject(int signal, int code, struct pt_regs *regs,
 383                                 unsigned long address)
 384 {
 385         siginfo_t info;
 386         void __user *pc = (void __user *)instruction_pointer(regs);
 387         const char *desc;
 388
 389         switch (signal) {
 390         case SIGILL:
 391                 desc = "undefined instruction";
 392                 break;
 393         case SIGSEGV:
 394                 desc = "illegal memory access";
 395                 break;
 396         default:
 397                 desc = "bad mode";
 398                 break;
 399         }
 400
 401         if (unhandled_signal(current, signal) &&
 402             show_unhandled_signals_ratelimited()) {
 403                 pr_info("%s[%d]: %s: pc=%p\n",
 404                         current->comm, task_pid_nr(current), desc, pc);
 405                 dump_instr(KERN_INFO, regs);
 406         }
 407
 408         info.si_signo = signal;
 409         info.si_errno = 0;
 410         info.si_code  = code;
 411         info.si_addr  = pc;
 412
 413         arm64_notify_die(desc, regs, &info, 0);
 414 }
 415
 416 /*
 417  * Set up process info to signal segmentation fault - called on access error.
 418  */
 419 void arm64_notify_segfault(struct pt_regs *regs, unsigned long addr)
 420 {
 421         int code;
 422
 423         down_read(&current->mm->mmap_sem);
 424         if (find_vma(current->mm, addr) == NULL)
 425                 code = SEGV_MAPERR;
 426         else
 427                 code = SEGV_ACCERR;
 428         up_read(&current->mm->mmap_sem);
 429
 430         force_signal_inject(SIGSEGV, code, regs, addr);
 431 }
 432
 433 asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
 434 {
 435         /* check for AArch32 breakpoint instructions */
 436         if (!aarch32_break_handler(regs))
 437                 return;
 438
 439         if (call_undef_hook(regs) == 0)
 440                 return;
 441
 442         force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
 443 }
 444
 445 int cpu_enable_cache_maint_trap(void *__unused)
 446 {
 447         config_sctlr_el1(SCTLR_EL1_UCI, 0);
 448         return 0;
 449 }
 450
 451 #define __user_cache_maint(insn, address, res)                  \
 452         if (address >= user_addr_max()) {                       \
 453                 res = -EFAULT;                                  \
 454         } else {                                                \
 455                 uaccess_ttbr0_enable();                         \
 456                 asm volatile (                                  \
 457                         "1:     " insn ", %1\n"                 \
 458                         "       mov     %w0, #0\n"              \
 459                         "2:\n"                                  \
 460                         "       .pushsection .fixup,\"ax\"\n"   \
 461                         "       .align  2\n"                    \
 462                         "3:     mov     %w0, %w2\n"             \
 463                         "       b       2b\n"                   \
 464                         "       .popsection\n"                  \
 465                         _ASM_EXTABLE(1b, 3b)                    \
 466                         : "=r" (res)                            \
 467                         : "r" (address), "i" (-EFAULT));        \
 468                 uaccess_ttbr0_disable();                        \
 469         }
 470
 471 static void user_cache_maint_handler(unsigned int esr, struct pt_regs *regs)
 472 {
 473         unsigned long address;
 474         int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
 475         int crm = (esr & ESR_ELx_SYS64_ISS_CRM_MASK) >> ESR_ELx_SYS64_ISS_CRM_SHIFT;
 476         int ret = 0;
 477
 478         address = untagged_addr(pt_regs_read_reg(regs, rt));
 479
 480         switch (crm) {
 481         case ESR_ELx_SYS64_ISS_CRM_DC_CVAU:     /* DC CVAU, gets promoted */
 482                 __user_cache_maint("dc civac", address, ret);
 483                 break;
 484         case ESR_ELx_SYS64_ISS_CRM_DC_CVAC:     /* DC CVAC, gets promoted */
 485                 __user_cache_maint("dc civac", address, ret);
 486                 break;
 487         case ESR_ELx_SYS64_ISS_CRM_DC_CIVAC:    /* DC CIVAC */
 488                 __user_cache_maint("dc civac", address, ret);
 489                 break;
 490         case ESR_ELx_SYS64_ISS_CRM_IC_IVAU:     /* IC IVAU */
 491                 __user_cache_maint("ic ivau", address, ret);
 492                 break;
 493         default:
 494                 force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
 495                 return;
 496         }
 497
 498         if (ret)
 499                 arm64_notify_segfault(regs, address);
 500         else
 501                 regs->pc += 4;
 502 }
 503
 504 static void ctr_read_handler(unsigned int esr, struct pt_regs *regs)
 505 {
 506         int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
 507         unsigned long val = arm64_ftr_reg_user_value(&arm64_ftr_reg_ctrel0);
 508
 509         pt_regs_write_reg(regs, rt, val);
 510
 511         regs->pc += 4;
 512 }
 513
 514 static void cntvct_read_handler(unsigned int esr, struct pt_regs *regs)
 515 {
 516         int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
 517
 518         pt_regs_write_reg(regs, rt, arch_counter_get_cntvct());
 519         regs->pc += 4;
 520 }
 521
 522 static void cntfrq_read_handler(unsigned int esr, struct pt_regs *regs)
 523 {
 524         int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
 525
 526         pt_regs_write_reg(regs, rt, arch_timer_get_rate());
 527         regs->pc += 4;
 528 }
 529
 530 struct sys64_hook {
 531         unsigned int esr_mask;
 532         unsigned int esr_val;
 533         void (*handler)(unsigned int esr, struct pt_regs *regs);
 534 };
 535
 536 static struct sys64_hook sys64_hooks[] = {
 537         {
 538                 .esr_mask = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_MASK,
 539                 .esr_val = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_VAL,
 540                 .handler = user_cache_maint_handler,
 541         },
 542         {
 543                 /* Trap read access to CTR_EL0 */
 544                 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
 545                 .esr_val = ESR_ELx_SYS64_ISS_SYS_CTR_READ,
 546                 .handler = ctr_read_handler,
 547         },
 548         {
 549                 /* Trap read access to CNTVCT_EL0 */
 550                 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
 551                 .esr_val = ESR_ELx_SYS64_ISS_SYS_CNTVCT,
 552                 .handler = cntvct_read_handler,
 553         },
 554         {
 555                 /* Trap read access to CNTFRQ_EL0 */
 556                 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
 557                 .esr_val = ESR_ELx_SYS64_ISS_SYS_CNTFRQ,
 558                 .handler = cntfrq_read_handler,
 559         },
 560         {},
 561 };
 562
 563 asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
 564 {
 565         struct sys64_hook *hook;
 566
 567         for (hook = sys64_hooks; hook->handler; hook++)
 568                 if ((hook->esr_mask & esr) == hook->esr_val) {
 569                         hook->handler(esr, regs);
 570                         return;
 571                 }
 572
 573         /*
 574          * New SYS instructions may previously have been undefined at EL0. Fall
 575          * back to our usual undefined instruction handler so that we handle
 576          * these consistently.
 577          */
 578         do_undefinstr(regs);
 579 }
 580
 581 long compat_arm_syscall(struct pt_regs *regs);
 582
 583 asmlinkage long do_ni_syscall(struct pt_regs *regs)
 584 {
 585 #ifdef CONFIG_COMPAT
 586         long ret;
 587         if (is_compat_task()) {
 588                 ret = compat_arm_syscall(regs);
 589                 if (ret != -ENOSYS)
 590                         return ret;
 591         }
 592 #endif
 593
 594         if (show_unhandled_signals_ratelimited()) {
 595                 pr_info("%s[%d]: syscall %d\n", current->comm,
 596                         task_pid_nr(current), (int)regs->syscallno);
 597                 dump_instr("", regs);
 598                 if (user_mode(regs))
 599                         __show_regs(regs);
 600         }
 601
 602         return sys_ni_syscall();
 603 }
 604
 605 static const char *esr_class_str[] = {
 606         [0 ... ESR_ELx_EC_MAX]          = "UNRECOGNIZED EC",
 607         [ESR_ELx_EC_UNKNOWN]            = "Unknown/Uncategorized",
 608         [ESR_ELx_EC_WFx]                = "WFI/WFE",
 609         [ESR_ELx_EC_CP15_32]            = "CP15 MCR/MRC",
 610         [ESR_ELx_EC_CP15_64]            = "CP15 MCRR/MRRC",
 611         [ESR_ELx_EC_CP14_MR]            = "CP14 MCR/MRC",
 612         [ESR_ELx_EC_CP14_LS]            = "CP14 LDC/STC",
 613         [ESR_ELx_EC_FP_ASIMD]           = "ASIMD",
 614         [ESR_ELx_EC_CP10_ID]            = "CP10 MRC/VMRS",
 615         [ESR_ELx_EC_CP14_64]            = "CP14 MCRR/MRRC",
 616         [ESR_ELx_EC_ILL]                = "PSTATE.IL",
 617         [ESR_ELx_EC_SVC32]              = "SVC (AArch32)",
 618         [ESR_ELx_EC_HVC32]              = "HVC (AArch32)",
 619         [ESR_ELx_EC_SMC32]              = "SMC (AArch32)",
 620         [ESR_ELx_EC_SVC64]              = "SVC (AArch64)",
 621         [ESR_ELx_EC_HVC64]              = "HVC (AArch64)",
 622         [ESR_ELx_EC_SMC64]              = "SMC (AArch64)",
 623         [ESR_ELx_EC_SYS64]              = "MSR/MRS (AArch64)",
 624         [ESR_ELx_EC_IMP_DEF]            = "EL3 IMP DEF",
 625         [ESR_ELx_EC_IABT_LOW]           = "IABT (lower EL)",
 626         [ESR_ELx_EC_IABT_CUR]           = "IABT (current EL)",
 627         [ESR_ELx_EC_PC_ALIGN]           = "PC Alignment",
 628         [ESR_ELx_EC_DABT_LOW]           = "DABT (lower EL)",
 629         [ESR_ELx_EC_DABT_CUR]           = "DABT (current EL)",
 630         [ESR_ELx_EC_SP_ALIGN]           = "SP Alignment",
 631         [ESR_ELx_EC_FP_EXC32]           = "FP (AArch32)",
 632         [ESR_ELx_EC_FP_EXC64]           = "FP (AArch64)",
 633         [ESR_ELx_EC_SERROR]             = "SError",
 634         [ESR_ELx_EC_BREAKPT_LOW]        = "Breakpoint (lower EL)",
 635         [ESR_ELx_EC_BREAKPT_CUR]        = "Breakpoint (current EL)",
 636         [ESR_ELx_EC_SOFTSTP_LOW]        = "Software Step (lower EL)",
 637         [ESR_ELx_EC_SOFTSTP_CUR]        = "Software Step (current EL)",
 638         [ESR_ELx_EC_WATCHPT_LOW]        = "Watchpoint (lower EL)",
 639         [ESR_ELx_EC_WATCHPT_CUR]        = "Watchpoint (current EL)",
 640         [ESR_ELx_EC_BKPT32]             = "BKPT (AArch32)",
 641         [ESR_ELx_EC_VECTOR32]           = "Vector catch (AArch32)",
 642         [ESR_ELx_EC_BRK64]              = "BRK (AArch64)",
 643 };
 644
 645 const char *esr_get_class_string(u32 esr)
 646 {
 647         return esr_class_str[ESR_ELx_EC(esr)];
 648 }
 649
 650 /*
 651  * bad_mode handles the impossible case in the exception vector. This is always
 652  * fatal.
 653  */
 654 asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
 655 {
 656         console_verbose();
 657
 658         pr_crit("Bad mode in %s handler detected on CPU%d, code 0x%08x -- %s\n",
 659                 handler[reason], smp_processor_id(), esr,
 660                 esr_get_class_string(esr));
 661
 662         die("Oops - bad mode", regs, 0);
 663         local_irq_disable();
 664         panic("bad mode");
 665 }
 666
 667 /*
 668  * bad_el0_sync handles unexpected, but potentially recoverable synchronous
 669  * exceptions taken from EL0. Unlike bad_mode, this returns.
 670  */
 671 asmlinkage void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr)
 672 {
 673         siginfo_t info;
 674         void __user *pc = (void __user *)instruction_pointer(regs);
 675         console_verbose();
 676
 677         pr_crit("Bad EL0 synchronous exception detected on CPU%d, code 0x%08x -- %s\n",
 678                 smp_processor_id(), esr, esr_get_class_string(esr));
 679         __show_regs(regs);
 680
 681         info.si_signo = SIGILL;
 682         info.si_errno = 0;
 683         info.si_code  = ILL_ILLOPC;
 684         info.si_addr  = pc;
 685
 686         current->thread.fault_address = 0;
 687         current->thread.fault_code = 0;
 688
 689         force_sig_info(info.si_signo, &info, current);
 690 }
 691
 692 void __pte_error(const char *file, int line, unsigned long val)
 693 {
 694         pr_err("%s:%d: bad pte %016lx.\n", file, line, val);
 695 }
 696
 697 void __pmd_error(const char *file, int line, unsigned long val)
 698 {
 699         pr_err("%s:%d: bad pmd %016lx.\n", file, line, val);
 700 }
 701
 702 void __pud_error(const char *file, int line, unsigned long val)
 703 {
 704         pr_err("%s:%d: bad pud %016lx.\n", file, line, val);
 705 }
 706
 707 void __pgd_error(const char *file, int line, unsigned long val)
 708 {
 709         pr_err("%s:%d: bad pgd %016lx.\n", file, line, val);
 710 }
 711
 712 /* GENERIC_BUG traps */
 713
 714 int is_valid_bugaddr(unsigned long addr)
 715 {
 716         /*
 717          * bug_handler() only called for BRK #BUG_BRK_IMM.
 718          * So the answer is trivial -- any spurious instances with no
 719          * bug table entry will be rejected by report_bug() and passed
 720          * back to the debug-monitors code and handled as a fatal
 721          * unexpected debug exception.
 722          */
 723         return 1;
 724 }
 725
 726 static int bug_handler(struct pt_regs *regs, unsigned int esr)
 727 {
 728         if (user_mode(regs))
 729                 return DBG_HOOK_ERROR;
 730
 731         switch (report_bug(regs->pc, regs)) {
 732         case BUG_TRAP_TYPE_BUG:
 733                 die("Oops - BUG", regs, 0);
 734                 break;
 735
 736         case BUG_TRAP_TYPE_WARN:
 737                 break;
 738
 739         default:
 740                 /* unknown/unrecognised bug trap type */
 741                 return DBG_HOOK_ERROR;
 742         }
 743
 744         /* If thread survives, skip over the BUG instruction and continue: */
 745         regs->pc += AARCH64_INSN_SIZE;  /* skip BRK and resume */
 746         return DBG_HOOK_HANDLED;
 747 }
 748
 749 static struct break_hook bug_break_hook = {
 750         .esr_val = 0xf2000000 | BUG_BRK_IMM,
 751         .esr_mask = 0xffffffff,
 752         .fn = bug_handler,
 753 };
 754
 755 /*
 756  * Initial handler for AArch64 BRK exceptions
 757  * This handler only used until debug_traps_init().
 758  */
 759 int __init early_brk64(unsigned long addr, unsigned int esr,
 760                 struct pt_regs *regs)
 761 {
 762         return bug_handler(regs, esr) != DBG_HOOK_HANDLED;
 763 }
 764
 765 /* This registration must happen early, before debug_traps_init(). */
 766 void __init trap_init(void)
 767 {
 768         register_break_hook(&bug_break_hook);
 769 }