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/sizes.h>
  36 #include <linux/syscalls.h>
  37 #include <linux/mm_types.h>
  38
  39 #include <asm/atomic.h>
  40 #include <asm/bug.h>
  41 #include <asm/debug-monitors.h>
  42 #include <asm/esr.h>
  43 #include <asm/insn.h>
  44 #include <asm/traps.h>
  45 #include <asm/smp.h>
  46 #include <asm/stack_pointer.h>
  47 #include <asm/stacktrace.h>
  48 #include <asm/exception.h>
  49 #include <asm/system_misc.h>
  50 #include <asm/sysreg.h>
  51
  52 static const char *handler[]= {
  53         "Synchronous Abort",
  54         "IRQ",
  55         "FIQ",
  56         "Error"
  57 };
  58
  59 int show_unhandled_signals = 1;
  60
  61 /*
  62  * Dump out the contents of some kernel memory nicely...
  63  */
  64 static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
  65                      unsigned long top)
  66 {
  67         unsigned long first;
  68         mm_segment_t fs;
  69         int i;
  70
  71         /*
  72          * We need to switch to kernel mode so that we can use __get_user
  73          * to safely read from kernel space.
  74          */
  75         fs = get_fs();
  76         set_fs(KERNEL_DS);
  77
  78         printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top);
  79
  80         for (first = bottom & ~31; first < top; first += 32) {
  81                 unsigned long p;
  82                 char str[sizeof(" 12345678") * 8 + 1];
  83
  84                 memset(str, ' ', sizeof(str));
  85                 str[sizeof(str) - 1] = '\0';
  86
  87                 for (p = first, i = 0; i < (32 / 8)
  88                                         && p < top; i++, p += 8) {
  89                         if (p >= bottom && p < top) {
  90                                 unsigned long val;
  91
  92                                 if (__get_user(val, (unsigned long *)p) == 0)
  93                                         sprintf(str + i * 17, " %016lx", val);
  94                                 else
  95                                         sprintf(str + i * 17, " ????????????????");
  96                         }
  97                 }
  98                 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
  99         }
 100
 101         set_fs(fs);
 102 }
 103
 104 static void dump_backtrace_entry(unsigned long where)
 105 {
 106         /*
 107          * Note that 'where' can have a physical address, but it's not handled.
 108          */
 109         print_ip_sym(where);
 110 }
 111
 112 static void __dump_instr(const char *lvl, struct pt_regs *regs)
 113 {
 114         unsigned long addr = instruction_pointer(regs);
 115         char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
 116         int i;
 117
 118         for (i = -4; i < 1; i++) {
 119                 unsigned int val, bad;
 120
 121                 bad = __get_user(val, &((u32 *)addr)[i]);
 122
 123                 if (!bad)
 124                         p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
 125                 else {
 126                         p += sprintf(p, "bad PC value");
 127                         break;
 128                 }
 129         }
 130         printk("%sCode: %s\n", lvl, str);
 131 }
 132
 133 static void dump_instr(const char *lvl, struct pt_regs *regs)
 134 {
 135         if (!user_mode(regs)) {
 136                 mm_segment_t fs = get_fs();
 137                 set_fs(KERNEL_DS);
 138                 __dump_instr(lvl, regs);
 139                 set_fs(fs);
 140         } else {
 141                 __dump_instr(lvl, regs);
 142         }
 143 }
 144
 145 void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 146 {
 147         struct stackframe frame;
 148         int skip;
 149
 150         pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
 151
 152         if (!tsk)
 153                 tsk = current;
 154
 155         if (!try_get_task_stack(tsk))
 156                 return;
 157
 158         if (tsk == current) {
 159                 frame.fp = (unsigned long)__builtin_frame_address(0);
 160                 frame.pc = (unsigned long)dump_backtrace;
 161         } else {
 162                 /*
 163                  * task blocked in __switch_to
 164                  */
 165                 frame.fp = thread_saved_fp(tsk);
 166                 frame.pc = thread_saved_pc(tsk);
 167         }
 168 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 169         frame.graph = tsk->curr_ret_stack;
 170 #endif
 171
 172         skip = !!regs;
 173         printk("Call trace:\n");
 174         while (1) {
 175                 unsigned long stack;
 176                 int ret;
 177
 178                 /* skip until specified stack frame */
 179                 if (!skip) {
 180                         dump_backtrace_entry(frame.pc);
 181                 } else if (frame.fp == regs->regs[29]) {
 182                         skip = 0;
 183                         /*
 184                          * Mostly, this is the case where this function is
 185                          * called in panic/abort. As exception handler's
 186                          * stack frame does not contain the corresponding pc
 187                          * at which an exception has taken place, use regs->pc
 188                          * instead.
 189                          */
 190                         dump_backtrace_entry(regs->pc);
 191                 }
 192                 ret = unwind_frame(tsk, &frame);
 193                 if (ret < 0)
 194                         break;
 195                 if (in_entry_text(frame.pc)) {
 196                         stack = frame.fp - offsetof(struct pt_regs, stackframe);
 197
 198                         if (on_accessible_stack(tsk, stack))
 199                                 dump_mem("", "Exception stack", stack,
 200                                          stack + sizeof(struct pt_regs));
 201                 }
 202         }
 203
 204         put_task_stack(tsk);
 205 }
 206
 207 void show_stack(struct task_struct *tsk, unsigned long *sp)
 208 {
 209         dump_backtrace(NULL, tsk);
 210         barrier();
 211 }
 212
 213 #ifdef CONFIG_PREEMPT
 214 #define S_PREEMPT " PREEMPT"
 215 #else
 216 #define S_PREEMPT ""
 217 #endif
 218 #define S_SMP " SMP"
 219
 220 static int __die(const char *str, int err, struct pt_regs *regs)
 221 {
 222         struct task_struct *tsk = current;
 223         static int die_counter;
 224         int ret;
 225
 226         pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
 227                  str, err, ++die_counter);
 228
 229         /* trap and error numbers are mostly meaningless on ARM */
 230         ret = notify_die(DIE_OOPS, str, regs, err, 0, SIGSEGV);
 231         if (ret == NOTIFY_STOP)
 232                 return ret;
 233
 234         print_modules();
 235         __show_regs(regs);
 236         pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
 237                  TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk),
 238                  end_of_stack(tsk));
 239
 240         if (!user_mode(regs)) {
 241                 dump_backtrace(regs, tsk);
 242                 dump_instr(KERN_EMERG, regs);
 243         }
 244
 245         return ret;
 246 }
 247
 248 static DEFINE_RAW_SPINLOCK(die_lock);
 249
 250 /*
 251  * This function is protected against re-entrancy.
 252  */
 253 void die(const char *str, struct pt_regs *regs, int err)
 254 {
 255         int ret;
 256         unsigned long flags;
 257
 258         raw_spin_lock_irqsave(&die_lock, flags);
 259
 260         oops_enter();
 261
 262         console_verbose();
 263         bust_spinlocks(1);
 264         ret = __die(str, err, regs);
 265
 266         if (regs && kexec_should_crash(current))
 267                 crash_kexec(regs);
 268
 269         bust_spinlocks(0);
 270         add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 271         oops_exit();
 272
 273         if (in_interrupt())
 274                 panic("Fatal exception in interrupt");
 275         if (panic_on_oops)
 276                 panic("Fatal exception");
 277
 278         raw_spin_unlock_irqrestore(&die_lock, flags);
 279
 280         if (ret != NOTIFY_STOP)
 281                 do_exit(SIGSEGV);
 282 }
 283
 284 void arm64_notify_die(const char *str, struct pt_regs *regs,
 285                       struct siginfo *info, int err)
 286 {
 287         if (user_mode(regs)) {
 288                 current->thread.fault_address = 0;
 289                 current->thread.fault_code = err;
 290                 force_sig_info(info->si_signo, info, current);
 291         } else {
 292                 die(str, regs, err);
 293         }
 294 }
 295
 296 static LIST_HEAD(undef_hook);
 297 static DEFINE_RAW_SPINLOCK(undef_lock);
 298
 299 void register_undef_hook(struct undef_hook *hook)
 300 {
 301         unsigned long flags;
 302
 303         raw_spin_lock_irqsave(&undef_lock, flags);
 304         list_add(&hook->node, &undef_hook);
 305         raw_spin_unlock_irqrestore(&undef_lock, flags);
 306 }
 307
 308 void unregister_undef_hook(struct undef_hook *hook)
 309 {
 310         unsigned long flags;
 311
 312         raw_spin_lock_irqsave(&undef_lock, flags);
 313         list_del(&hook->node);
 314         raw_spin_unlock_irqrestore(&undef_lock, flags);
 315 }
 316
 317 static int call_undef_hook(struct pt_regs *regs)
 318 {
 319         struct undef_hook *hook;
 320         unsigned long flags;
 321         u32 instr;
 322         int (*fn)(struct pt_regs *regs, u32 instr) = NULL;
 323         void __user *pc = (void __user *)instruction_pointer(regs);
 324
 325         if (!user_mode(regs))
 326                 return 1;
 327
 328         if (compat_thumb_mode(regs)) {
 329                 /* 16-bit Thumb instruction */
 330                 __le16 instr_le;
 331                 if (get_user(instr_le, (__le16 __user *)pc))
 332                         goto exit;
 333                 instr = le16_to_cpu(instr_le);
 334                 if (aarch32_insn_is_wide(instr)) {
 335                         u32 instr2;
 336
 337                         if (get_user(instr_le, (__le16 __user *)(pc + 2)))
 338                                 goto exit;
 339                         instr2 = le16_to_cpu(instr_le);
 340                         instr = (instr << 16) | instr2;
 341                 }
 342         } else {
 343                 /* 32-bit ARM instruction */
 344                 __le32 instr_le;
 345                 if (get_user(instr_le, (__le32 __user *)pc))
 346                         goto exit;
 347                 instr = le32_to_cpu(instr_le);
 348         }
 349
 350         raw_spin_lock_irqsave(&undef_lock, flags);
 351         list_for_each_entry(hook, &undef_hook, node)
 352                 if ((instr & hook->instr_mask) == hook->instr_val &&
 353                         (regs->pstate & hook->pstate_mask) == hook->pstate_val)
 354                         fn = hook->fn;
 355
 356         raw_spin_unlock_irqrestore(&undef_lock, flags);
 357 exit:
 358         return fn ? fn(regs, instr) : 1;
 359 }
 360
 361 static void force_signal_inject(int signal, int code, struct pt_regs *regs,
 362                                 unsigned long address)
 363 {
 364         siginfo_t info;
 365         void __user *pc = (void __user *)instruction_pointer(regs);
 366         const char *desc;
 367
 368         switch (signal) {
 369         case SIGILL:
 370                 desc = "undefined instruction";
 371                 break;
 372         case SIGSEGV:
 373                 desc = "illegal memory access";
 374                 break;
 375         default:
 376                 desc = "bad mode";
 377                 break;
 378         }
 379
 380         if (unhandled_signal(current, signal) &&
 381             show_unhandled_signals_ratelimited()) {
 382                 pr_info("%s[%d]: %s: pc=%p\n",
 383                         current->comm, task_pid_nr(current), desc, pc);
 384                 dump_instr(KERN_INFO, regs);
 385         }
 386
 387         info.si_signo = signal;
 388         info.si_errno = 0;
 389         info.si_code  = code;
 390         info.si_addr  = pc;
 391
 392         arm64_notify_die(desc, regs, &info, 0);
 393 }
 394
 395 /*
 396  * Set up process info to signal segmentation fault - called on access error.
 397  */
 398 void arm64_notify_segfault(struct pt_regs *regs, unsigned long addr)
 399 {
 400         int code;
 401
 402         down_read(&current->mm->mmap_sem);
 403         if (find_vma(current->mm, addr) == NULL)
 404                 code = SEGV_MAPERR;
 405         else
 406                 code = SEGV_ACCERR;
 407         up_read(&current->mm->mmap_sem);
 408
 409         force_signal_inject(SIGSEGV, code, regs, addr);
 410 }
 411
 412 asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
 413 {
 414         /* check for AArch32 breakpoint instructions */
 415         if (!aarch32_break_handler(regs))
 416                 return;
 417
 418         if (call_undef_hook(regs) == 0)
 419                 return;
 420
 421         force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
 422 }
 423
 424 int cpu_enable_cache_maint_trap(void *__unused)
 425 {
 426         config_sctlr_el1(SCTLR_EL1_UCI, 0);
 427         return 0;
 428 }
 429
 430 #define __user_cache_maint(insn, address, res)                  \
 431         if (address >= user_addr_max()) {                       \
 432                 res = -EFAULT;                                  \
 433         } else {                                                \
 434                 uaccess_ttbr0_enable();                         \
 435                 asm volatile (                                  \
 436                         "1:     " insn ", %1\n"                 \
 437                         "       mov     %w0, #0\n"              \
 438                         "2:\n"                                  \
 439                         "       .pushsection .fixup,\"ax\"\n"   \
 440                         "       .align  2\n"                    \
 441                         "3:     mov     %w0, %w2\n"             \
 442                         "       b       2b\n"                   \
 443                         "       .popsection\n"                  \
 444                         _ASM_EXTABLE(1b, 3b)                    \
 445                         : "=r" (res)                            \
 446                         : "r" (address), "i" (-EFAULT));        \
 447                 uaccess_ttbr0_disable();                        \
 448         }
 449
 450 static void user_cache_maint_handler(unsigned int esr, struct pt_regs *regs)
 451 {
 452         unsigned long address;
 453         int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
 454         int crm = (esr & ESR_ELx_SYS64_ISS_CRM_MASK) >> ESR_ELx_SYS64_ISS_CRM_SHIFT;
 455         int ret = 0;
 456
 457         address = untagged_addr(pt_regs_read_reg(regs, rt));
 458
 459         switch (crm) {
 460         case ESR_ELx_SYS64_ISS_CRM_DC_CVAU:     /* DC CVAU, gets promoted */
 461                 __user_cache_maint("dc civac", address, ret);
 462                 break;
 463         case ESR_ELx_SYS64_ISS_CRM_DC_CVAC:     /* DC CVAC, gets promoted */
 464                 __user_cache_maint("dc civac", address, ret);
 465                 break;
 466         case ESR_ELx_SYS64_ISS_CRM_DC_CVAP:     /* DC CVAP */
 467                 __user_cache_maint("sys 3, c7, c12, 1", address, ret);
 468                 break;
 469         case ESR_ELx_SYS64_ISS_CRM_DC_CIVAC:    /* DC CIVAC */
 470                 __user_cache_maint("dc civac", address, ret);
 471                 break;
 472         case ESR_ELx_SYS64_ISS_CRM_IC_IVAU:     /* IC IVAU */
 473                 __user_cache_maint("ic ivau", address, ret);
 474                 break;
 475         default:
 476                 force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
 477                 return;
 478         }
 479
 480         if (ret)
 481                 arm64_notify_segfault(regs, address);
 482         else
 483                 regs->pc += 4;
 484 }
 485
 486 static void ctr_read_handler(unsigned int esr, struct pt_regs *regs)
 487 {
 488         int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
 489         unsigned long val = arm64_ftr_reg_user_value(&arm64_ftr_reg_ctrel0);
 490
 491         pt_regs_write_reg(regs, rt, val);
 492
 493         regs->pc += 4;
 494 }
 495
 496 static void cntvct_read_handler(unsigned int esr, struct pt_regs *regs)
 497 {
 498         int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
 499
 500         pt_regs_write_reg(regs, rt, arch_counter_get_cntvct());
 501         regs->pc += 4;
 502 }
 503
 504 static void cntfrq_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
 508         pt_regs_write_reg(regs, rt, arch_timer_get_rate());
 509         regs->pc += 4;
 510 }
 511
 512 struct sys64_hook {
 513         unsigned int esr_mask;
 514         unsigned int esr_val;
 515         void (*handler)(unsigned int esr, struct pt_regs *regs);
 516 };
 517
 518 static struct sys64_hook sys64_hooks[] = {
 519         {
 520                 .esr_mask = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_MASK,
 521                 .esr_val = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_VAL,
 522                 .handler = user_cache_maint_handler,
 523         },
 524         {
 525                 /* Trap read access to CTR_EL0 */
 526                 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
 527                 .esr_val = ESR_ELx_SYS64_ISS_SYS_CTR_READ,
 528                 .handler = ctr_read_handler,
 529         },
 530         {
 531                 /* Trap read access to CNTVCT_EL0 */
 532                 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
 533                 .esr_val = ESR_ELx_SYS64_ISS_SYS_CNTVCT,
 534                 .handler = cntvct_read_handler,
 535         },
 536         {
 537                 /* Trap read access to CNTFRQ_EL0 */
 538                 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
 539                 .esr_val = ESR_ELx_SYS64_ISS_SYS_CNTFRQ,
 540                 .handler = cntfrq_read_handler,
 541         },
 542         {},
 543 };
 544
 545 asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
 546 {
 547         struct sys64_hook *hook;
 548
 549         for (hook = sys64_hooks; hook->handler; hook++)
 550                 if ((hook->esr_mask & esr) == hook->esr_val) {
 551                         hook->handler(esr, regs);
 552                         return;
 553                 }
 554
 555         /*
 556          * New SYS instructions may previously have been undefined at EL0. Fall
 557          * back to our usual undefined instruction handler so that we handle
 558          * these consistently.
 559          */
 560         do_undefinstr(regs);
 561 }
 562
 563 long compat_arm_syscall(struct pt_regs *regs);
 564
 565 asmlinkage long do_ni_syscall(struct pt_regs *regs)
 566 {
 567 #ifdef CONFIG_COMPAT
 568         long ret;
 569         if (is_compat_task()) {
 570                 ret = compat_arm_syscall(regs);
 571                 if (ret != -ENOSYS)
 572                         return ret;
 573         }
 574 #endif
 575
 576         if (show_unhandled_signals_ratelimited()) {
 577                 pr_info("%s[%d]: syscall %d\n", current->comm,
 578                         task_pid_nr(current), regs->syscallno);
 579                 dump_instr("", regs);
 580                 if (user_mode(regs))
 581                         __show_regs(regs);
 582         }
 583
 584         return sys_ni_syscall();
 585 }
 586
 587 static const char *esr_class_str[] = {
 588         [0 ... ESR_ELx_EC_MAX]          = "UNRECOGNIZED EC",
 589         [ESR_ELx_EC_UNKNOWN]            = "Unknown/Uncategorized",
 590         [ESR_ELx_EC_WFx]                = "WFI/WFE",
 591         [ESR_ELx_EC_CP15_32]            = "CP15 MCR/MRC",
 592         [ESR_ELx_EC_CP15_64]            = "CP15 MCRR/MRRC",
 593         [ESR_ELx_EC_CP14_MR]            = "CP14 MCR/MRC",
 594         [ESR_ELx_EC_CP14_LS]            = "CP14 LDC/STC",
 595         [ESR_ELx_EC_FP_ASIMD]           = "ASIMD",
 596         [ESR_ELx_EC_CP10_ID]            = "CP10 MRC/VMRS",
 597         [ESR_ELx_EC_CP14_64]            = "CP14 MCRR/MRRC",
 598         [ESR_ELx_EC_ILL]                = "PSTATE.IL",
 599         [ESR_ELx_EC_SVC32]              = "SVC (AArch32)",
 600         [ESR_ELx_EC_HVC32]              = "HVC (AArch32)",
 601         [ESR_ELx_EC_SMC32]              = "SMC (AArch32)",
 602         [ESR_ELx_EC_SVC64]              = "SVC (AArch64)",
 603         [ESR_ELx_EC_HVC64]              = "HVC (AArch64)",
 604         [ESR_ELx_EC_SMC64]              = "SMC (AArch64)",
 605         [ESR_ELx_EC_SYS64]              = "MSR/MRS (AArch64)",
 606         [ESR_ELx_EC_IMP_DEF]            = "EL3 IMP DEF",
 607         [ESR_ELx_EC_IABT_LOW]           = "IABT (lower EL)",
 608         [ESR_ELx_EC_IABT_CUR]           = "IABT (current EL)",
 609         [ESR_ELx_EC_PC_ALIGN]           = "PC Alignment",
 610         [ESR_ELx_EC_DABT_LOW]           = "DABT (lower EL)",
 611         [ESR_ELx_EC_DABT_CUR]           = "DABT (current EL)",
 612         [ESR_ELx_EC_SP_ALIGN]           = "SP Alignment",
 613         [ESR_ELx_EC_FP_EXC32]           = "FP (AArch32)",
 614         [ESR_ELx_EC_FP_EXC64]           = "FP (AArch64)",
 615         [ESR_ELx_EC_SERROR]             = "SError",
 616         [ESR_ELx_EC_BREAKPT_LOW]        = "Breakpoint (lower EL)",
 617         [ESR_ELx_EC_BREAKPT_CUR]        = "Breakpoint (current EL)",
 618         [ESR_ELx_EC_SOFTSTP_LOW]        = "Software Step (lower EL)",
 619         [ESR_ELx_EC_SOFTSTP_CUR]        = "Software Step (current EL)",
 620         [ESR_ELx_EC_WATCHPT_LOW]        = "Watchpoint (lower EL)",
 621         [ESR_ELx_EC_WATCHPT_CUR]        = "Watchpoint (current EL)",
 622         [ESR_ELx_EC_BKPT32]             = "BKPT (AArch32)",
 623         [ESR_ELx_EC_VECTOR32]           = "Vector catch (AArch32)",
 624         [ESR_ELx_EC_BRK64]              = "BRK (AArch64)",
 625 };
 626
 627 const char *esr_get_class_string(u32 esr)
 628 {
 629         return esr_class_str[ESR_ELx_EC(esr)];
 630 }
 631
 632 /*
 633  * bad_mode handles the impossible case in the exception vector. This is always
 634  * fatal.
 635  */
 636 asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
 637 {
 638         console_verbose();
 639
 640         pr_crit("Bad mode in %s handler detected on CPU%d, code 0x%08x -- %s\n",
 641                 handler[reason], smp_processor_id(), esr,
 642                 esr_get_class_string(esr));
 643
 644         die("Oops - bad mode", regs, 0);
 645         local_irq_disable();
 646         panic("bad mode");
 647 }
 648
 649 /*
 650  * bad_el0_sync handles unexpected, but potentially recoverable synchronous
 651  * exceptions taken from EL0. Unlike bad_mode, this returns.
 652  */
 653 asmlinkage void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr)
 654 {
 655         siginfo_t info;
 656         void __user *pc = (void __user *)instruction_pointer(regs);
 657         console_verbose();
 658
 659         pr_crit("Bad EL0 synchronous exception detected on CPU%d, code 0x%08x -- %s\n",
 660                 smp_processor_id(), esr, esr_get_class_string(esr));
 661         __show_regs(regs);
 662
 663         info.si_signo = SIGILL;
 664         info.si_errno = 0;
 665         info.si_code  = ILL_ILLOPC;
 666         info.si_addr  = pc;
 667
 668         current->thread.fault_address = 0;
 669         current->thread.fault_code = 0;
 670
 671         force_sig_info(info.si_signo, &info, current);
 672 }
 673
 674 #ifdef CONFIG_VMAP_STACK
 675
 676 DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack)
 677         __aligned(16);
 678
 679 asmlinkage void handle_bad_stack(struct pt_regs *regs)
 680 {
 681         unsigned long tsk_stk = (unsigned long)current->stack;
 682         unsigned long irq_stk = (unsigned long)this_cpu_read(irq_stack_ptr);
 683         unsigned long ovf_stk = (unsigned long)this_cpu_ptr(overflow_stack);
 684         unsigned int esr = read_sysreg(esr_el1);
 685         unsigned long far = read_sysreg(far_el1);
 686
 687         console_verbose();
 688         pr_emerg("Insufficient stack space to handle exception!");
 689
 690         pr_emerg("ESR: 0x%08x -- %s\n", esr, esr_get_class_string(esr));
 691         pr_emerg("FAR: 0x%016lx\n", far);
 692
 693         pr_emerg("Task stack:     [0x%016lx..0x%016lx]\n",
 694                  tsk_stk, tsk_stk + THREAD_SIZE);
 695         pr_emerg("IRQ stack:      [0x%016lx..0x%016lx]\n",
 696                  irq_stk, irq_stk + THREAD_SIZE);
 697         pr_emerg("Overflow stack: [0x%016lx..0x%016lx]\n",
 698                  ovf_stk, ovf_stk + OVERFLOW_STACK_SIZE);
 699
 700         __show_regs(regs);
 701
 702         /*
 703          * We use nmi_panic to limit the potential for recusive overflows, and
 704          * to get a better stack trace.
 705          */
 706         nmi_panic(NULL, "kernel stack overflow");
 707         cpu_park_loop();
 708 }
 709 #endif
 710
 711 void __pte_error(const char *file, int line, unsigned long val)
 712 {
 713         pr_err("%s:%d: bad pte %016lx.\n", file, line, val);
 714 }
 715
 716 void __pmd_error(const char *file, int line, unsigned long val)
 717 {
 718         pr_err("%s:%d: bad pmd %016lx.\n", file, line, val);
 719 }
 720
 721 void __pud_error(const char *file, int line, unsigned long val)
 722 {
 723         pr_err("%s:%d: bad pud %016lx.\n", file, line, val);
 724 }
 725
 726 void __pgd_error(const char *file, int line, unsigned long val)
 727 {
 728         pr_err("%s:%d: bad pgd %016lx.\n", file, line, val);
 729 }
 730
 731 /* GENERIC_BUG traps */
 732
 733 int is_valid_bugaddr(unsigned long addr)
 734 {
 735         /*
 736          * bug_handler() only called for BRK #BUG_BRK_IMM.
 737          * So the answer is trivial -- any spurious instances with no
 738          * bug table entry will be rejected by report_bug() and passed
 739          * back to the debug-monitors code and handled as a fatal
 740          * unexpected debug exception.
 741          */
 742         return 1;
 743 }
 744
 745 static int bug_handler(struct pt_regs *regs, unsigned int esr)
 746 {
 747         if (user_mode(regs))
 748                 return DBG_HOOK_ERROR;
 749
 750         switch (report_bug(regs->pc, regs)) {
 751         case BUG_TRAP_TYPE_BUG:
 752                 die("Oops - BUG", regs, 0);
 753                 break;
 754
 755         case BUG_TRAP_TYPE_WARN:
 756                 break;
 757
 758         default:
 759                 /* unknown/unrecognised bug trap type */
 760                 return DBG_HOOK_ERROR;
 761         }
 762
 763         /* If thread survives, skip over the BUG instruction and continue: */
 764         regs->pc += AARCH64_INSN_SIZE;  /* skip BRK and resume */
 765         return DBG_HOOK_HANDLED;
 766 }
 767
 768 static struct break_hook bug_break_hook = {
 769         .esr_val = 0xf2000000 | BUG_BRK_IMM,
 770         .esr_mask = 0xffffffff,
 771         .fn = bug_handler,
 772 };
 773
 774 /*
 775  * Initial handler for AArch64 BRK exceptions
 776  * This handler only used until debug_traps_init().
 777  */
 778 int __init early_brk64(unsigned long addr, unsigned int esr,
 779                 struct pt_regs *regs)
 780 {
 781         return bug_handler(regs, esr) != DBG_HOOK_HANDLED;
 782 }
 783
 784 /* This registration must happen early, before debug_traps_init(). */
 785 void __init trap_init(void)
 786 {
 787         register_break_hook(&bug_break_hook);
 788 }