arch/arm/kernel/traps.c

   1 /*
   2  *  linux/arch/arm/kernel/traps.c
   3  *
   4  *  Copyright (C) 1995-2009 Russell King
   5  *  Fragments that appear the same as linux/arch/i386/kernel/traps.c (C) Linus Torvalds
   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  *  'traps.c' handles hardware exceptions after we have saved some state in
  12  *  'linux/arch/arm/lib/traps.S'.  Mostly a debugging aid, but will probably
  13  *  kill the offending process.
  14  */
  15 #include <linux/signal.h>
  16 #include <linux/personality.h>
  17 #include <linux/kallsyms.h>
  18 #include <linux/spinlock.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/hardirq.h>
  21 #include <linux/kdebug.h>
  22 #include <linux/module.h>
  23 #include <linux/kexec.h>
  24 #include <linux/bug.h>
  25 #include <linux/delay.h>
  26 #include <linux/init.h>
  27 #include <linux/sched.h>
  28 #include <linux/irq.h>
  29
  30 #include <linux/atomic.h>
  31 #include <asm/cacheflush.h>
  32 #include <asm/exception.h>
  33 #include <asm/unistd.h>
  34 #include <asm/traps.h>
  35 #include <asm/ptrace.h>
  36 #include <asm/unwind.h>
  37 #include <asm/tls.h>
  38 #include <asm/system_misc.h>
  39 #include <asm/opcodes.h>
  40
  41
  42 static const char *handler[]= {
  43         "prefetch abort",
  44         "data abort",
  45         "address exception",
  46         "interrupt",
  47         "undefined instruction",
  48 };
  49
  50 void *vectors_page;
  51
  52 #ifdef CONFIG_DEBUG_USER
  53 unsigned int user_debug;
  54
  55 static int __init user_debug_setup(char *str)
  56 {
  57         get_option(&str, &user_debug);
  58         return 1;
  59 }
  60 __setup("user_debug=", user_debug_setup);
  61 #endif
  62
  63 static void dump_mem(const char *, const char *, unsigned long, unsigned long);
  64
  65 void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame)
  66 {
  67 #ifdef CONFIG_KALLSYMS
  68         printk("[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from);
  69 #else
  70         printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
  71 #endif
  72
  73         if (in_exception_text(where))
  74                 dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs));
  75 }
  76
  77 #ifndef CONFIG_ARM_UNWIND
  78 /*
  79  * Stack pointers should always be within the kernels view of
  80  * physical memory.  If it is not there, then we can't dump
  81  * out any information relating to the stack.
  82  */
  83 static int verify_stack(unsigned long sp)
  84 {
  85         if (sp < PAGE_OFFSET ||
  86             (sp > (unsigned long)high_memory && high_memory != NULL))
  87                 return -EFAULT;
  88
  89         return 0;
  90 }
  91 #endif
  92
  93 /*
  94  * Dump out the contents of some memory nicely...
  95  */
  96 static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
  97                      unsigned long top)
  98 {
  99         unsigned long first;
 100         mm_segment_t fs;
 101         int i;
 102
 103         /*
 104          * We need to switch to kernel mode so that we can use __get_user
 105          * to safely read from kernel space.  Note that we now dump the
 106          * code first, just in case the backtrace kills us.
 107          */
 108         fs = get_fs();
 109         set_fs(KERNEL_DS);
 110
 111         printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top);
 112
 113         for (first = bottom & ~31; first < top; first += 32) {
 114                 unsigned long p;
 115                 char str[sizeof(" 12345678") * 8 + 1];
 116
 117                 memset(str, ' ', sizeof(str));
 118                 str[sizeof(str) - 1] = '\0';
 119
 120                 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
 121                         if (p >= bottom && p < top) {
 122                                 unsigned long val;
 123                                 if (__get_user(val, (unsigned long *)p) == 0)
 124                                         sprintf(str + i * 9, " %08lx", val);
 125                                 else
 126                                         sprintf(str + i * 9, " ????????");
 127                         }
 128                 }
 129                 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
 130         }
 131
 132         set_fs(fs);
 133 }
 134
 135 static void dump_instr(const char *lvl, struct pt_regs *regs)
 136 {
 137         unsigned long addr = instruction_pointer(regs);
 138         const int thumb = thumb_mode(regs);
 139         const int width = thumb ? 4 : 8;
 140         mm_segment_t fs;
 141         char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
 142         int i;
 143
 144         /*
 145          * We need to switch to kernel mode so that we can use __get_user
 146          * to safely read from kernel space.  Note that we now dump the
 147          * code first, just in case the backtrace kills us.
 148          */
 149         fs = get_fs();
 150         set_fs(KERNEL_DS);
 151
 152         for (i = -4; i < 1 + !!thumb; i++) {
 153                 unsigned int val, bad;
 154
 155                 if (thumb)
 156                         bad = __get_user(val, &((u16 *)addr)[i]);
 157                 else
 158                         bad = __get_user(val, &((u32 *)addr)[i]);
 159
 160                 if (!bad)
 161                         p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ",
 162                                         width, val);
 163                 else {
 164                         p += sprintf(p, "bad PC value");
 165                         break;
 166                 }
 167         }
 168         printk("%sCode: %s\n", lvl, str);
 169
 170         set_fs(fs);
 171 }
 172
 173 #ifdef CONFIG_ARM_UNWIND
 174 static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 175 {
 176         unwind_backtrace(regs, tsk);
 177 }
 178 #else
 179 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 180 {
 181         unsigned int fp, mode;
 182         int ok = 1;
 183
 184         printk("Backtrace: ");
 185
 186         if (!tsk)
 187                 tsk = current;
 188
 189         if (regs) {
 190                 fp = frame_pointer(regs);
 191                 mode = processor_mode(regs);
 192         } else if (tsk != current) {
 193                 fp = thread_saved_fp(tsk);
 194                 mode = 0x10;
 195         } else {
 196                 asm("mov %0, fp" : "=r" (fp) : : "cc");
 197                 mode = 0x10;
 198         }
 199
 200         if (!fp) {
 201                 pr_cont("no frame pointer");
 202                 ok = 0;
 203         } else if (verify_stack(fp)) {
 204                 pr_cont("invalid frame pointer 0x%08x", fp);
 205                 ok = 0;
 206         } else if (fp < (unsigned long)end_of_stack(tsk))
 207                 pr_cont("frame pointer underflow");
 208         pr_cont("\n");
 209
 210         if (ok)
 211                 c_backtrace(fp, mode);
 212 }
 213 #endif
 214
 215 void show_stack(struct task_struct *tsk, unsigned long *sp)
 216 {
 217         dump_backtrace(NULL, tsk);
 218         barrier();
 219 }
 220
 221 #ifdef CONFIG_PREEMPT
 222 #define S_PREEMPT " PREEMPT"
 223 #else
 224 #define S_PREEMPT ""
 225 #endif
 226 #ifdef CONFIG_SMP
 227 #define S_SMP " SMP"
 228 #else
 229 #define S_SMP ""
 230 #endif
 231 #ifdef CONFIG_THUMB2_KERNEL
 232 #define S_ISA " THUMB2"
 233 #else
 234 #define S_ISA " ARM"
 235 #endif
 236
 237 static int __die(const char *str, int err, struct pt_regs *regs)
 238 {
 239         struct task_struct *tsk = current;
 240         static int die_counter;
 241         int ret;
 242
 243         pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP S_ISA "\n",
 244                  str, err, ++die_counter);
 245
 246         /* trap and error numbers are mostly meaningless on ARM */
 247         ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV);
 248         if (ret == NOTIFY_STOP)
 249                 return 1;
 250
 251         print_modules();
 252         __show_regs(regs);
 253         pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
 254                  TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk));
 255
 256         if (!user_mode(regs) || in_interrupt()) {
 257                 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_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 0;
 264 }
 265
 266 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
 267 static int die_owner = -1;
 268 static unsigned int die_nest_count;
 269
 270 static unsigned long oops_begin(void)
 271 {
 272         int cpu;
 273         unsigned long flags;
 274
 275         oops_enter();
 276
 277         /* racy, but better than risking deadlock. */
 278         raw_local_irq_save(flags);
 279         cpu = smp_processor_id();
 280         if (!arch_spin_trylock(&die_lock)) {
 281                 if (cpu == die_owner)
 282                         /* nested oops. should stop eventually */;
 283                 else
 284                         arch_spin_lock(&die_lock);
 285         }
 286         die_nest_count++;
 287         die_owner = cpu;
 288         console_verbose();
 289         bust_spinlocks(1);
 290         return flags;
 291 }
 292
 293 static void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
 294 {
 295         if (regs && kexec_should_crash(current))
 296                 crash_kexec(regs);
 297
 298         bust_spinlocks(0);
 299         die_owner = -1;
 300         add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 301         die_nest_count--;
 302         if (!die_nest_count)
 303                 /* Nest count reaches zero, release the lock. */
 304                 arch_spin_unlock(&die_lock);
 305         raw_local_irq_restore(flags);
 306         oops_exit();
 307
 308         if (in_interrupt())
 309                 panic("Fatal exception in interrupt");
 310         if (panic_on_oops)
 311                 panic("Fatal exception");
 312         if (signr)
 313                 do_exit(signr);
 314 }
 315
 316 /*
 317  * This function is protected against re-entrancy.
 318  */
 319 void die(const char *str, struct pt_regs *regs, int err)
 320 {
 321         enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE;
 322         unsigned long flags = oops_begin();
 323         int sig = SIGSEGV;
 324
 325         if (!user_mode(regs))
 326                 bug_type = report_bug(regs->ARM_pc, regs);
 327         if (bug_type != BUG_TRAP_TYPE_NONE)
 328                 str = "Oops - BUG";
 329
 330         if (__die(str, err, regs))
 331                 sig = 0;
 332
 333         oops_end(flags, regs, sig);
 334 }
 335
 336 void arm_notify_die(const char *str, struct pt_regs *regs,
 337                 struct siginfo *info, unsigned long err, unsigned long trap)
 338 {
 339         if (user_mode(regs)) {
 340                 current->thread.error_code = err;
 341                 current->thread.trap_no = trap;
 342
 343                 force_sig_info(info->si_signo, info, current);
 344         } else {
 345                 die(str, regs, err);
 346         }
 347 }
 348
 349 #ifdef CONFIG_GENERIC_BUG
 350
 351 int is_valid_bugaddr(unsigned long pc)
 352 {
 353 #ifdef CONFIG_THUMB2_KERNEL
 354         u16 bkpt;
 355         u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE);
 356 #else
 357         u32 bkpt;
 358         u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE);
 359 #endif
 360
 361         if (probe_kernel_address((unsigned *)pc, bkpt))
 362                 return 0;
 363
 364         return bkpt == insn;
 365 }
 366
 367 #endif
 368
 369 static LIST_HEAD(undef_hook);
 370 static DEFINE_RAW_SPINLOCK(undef_lock);
 371
 372 void register_undef_hook(struct undef_hook *hook)
 373 {
 374         unsigned long flags;
 375
 376         raw_spin_lock_irqsave(&undef_lock, flags);
 377         list_add(&hook->node, &undef_hook);
 378         raw_spin_unlock_irqrestore(&undef_lock, flags);
 379 }
 380
 381 void unregister_undef_hook(struct undef_hook *hook)
 382 {
 383         unsigned long flags;
 384
 385         raw_spin_lock_irqsave(&undef_lock, flags);
 386         list_del(&hook->node);
 387         raw_spin_unlock_irqrestore(&undef_lock, flags);
 388 }
 389
 390 static int call_undef_hook(struct pt_regs *regs, unsigned int instr)
 391 {
 392         struct undef_hook *hook;
 393         unsigned long flags;
 394         int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL;
 395
 396         raw_spin_lock_irqsave(&undef_lock, flags);
 397         list_for_each_entry(hook, &undef_hook, node)
 398                 if ((instr & hook->instr_mask) == hook->instr_val &&
 399                     (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val)
 400                         fn = hook->fn;
 401         raw_spin_unlock_irqrestore(&undef_lock, flags);
 402
 403         return fn ? fn(regs, instr) : 1;
 404 }
 405
 406 asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
 407 {
 408         unsigned int instr;
 409         siginfo_t info;
 410         void __user *pc;
 411
 412         pc = (void __user *)instruction_pointer(regs);
 413
 414         if (processor_mode(regs) == SVC_MODE) {
 415 #ifdef CONFIG_THUMB2_KERNEL
 416                 if (thumb_mode(regs)) {
 417                         instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]);
 418                         if (is_wide_instruction(instr)) {
 419                                 u16 inst2;
 420                                 inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]);
 421                                 instr = __opcode_thumb32_compose(instr, inst2);
 422                         }
 423                 } else
 424 #endif
 425                         instr = __mem_to_opcode_arm(*(u32 *) pc);
 426         } else if (thumb_mode(regs)) {
 427                 if (get_user(instr, (u16 __user *)pc))
 428                         goto die_sig;
 429                 instr = __mem_to_opcode_thumb16(instr);
 430                 if (is_wide_instruction(instr)) {
 431                         unsigned int instr2;
 432                         if (get_user(instr2, (u16 __user *)pc+1))
 433                                 goto die_sig;
 434                         instr2 = __mem_to_opcode_thumb16(instr2);
 435                         instr = __opcode_thumb32_compose(instr, instr2);
 436                 }
 437         } else {
 438                 if (get_user(instr, (u32 __user *)pc))
 439                         goto die_sig;
 440                 instr = __mem_to_opcode_arm(instr);
 441         }
 442
 443         if (call_undef_hook(regs, instr) == 0)
 444                 return;
 445
 446 die_sig:
 447 #ifdef CONFIG_DEBUG_USER
 448         if (user_debug & UDBG_UNDEFINED) {
 449                 pr_info("%s (%d): undefined instruction: pc=%p\n",
 450                         current->comm, task_pid_nr(current), pc);
 451                 __show_regs(regs);
 452                 dump_instr(KERN_INFO, regs);
 453         }
 454 #endif
 455
 456         info.si_signo = SIGILL;
 457         info.si_errno = 0;
 458         info.si_code  = ILL_ILLOPC;
 459         info.si_addr  = pc;
 460
 461         arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6);
 462 }
 463
 464 /*
 465  * Handle FIQ similarly to NMI on x86 systems.
 466  *
 467  * The runtime environment for NMIs is extremely restrictive
 468  * (NMIs can pre-empt critical sections meaning almost all locking is
 469  * forbidden) meaning this default FIQ handling must only be used in
 470  * circumstances where non-maskability improves robustness, such as
 471  * watchdog or debug logic.
 472  *
 473  * This handler is not appropriate for general purpose use in drivers
 474  * platform code and can be overrideen using set_fiq_handler.
 475  */
 476 asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs)
 477 {
 478         struct pt_regs *old_regs = set_irq_regs(regs);
 479
 480         nmi_enter();
 481
 482         /* nop. FIQ handlers for special arch/arm features can be added here. */
 483
 484         nmi_exit();
 485
 486         set_irq_regs(old_regs);
 487 }
 488
 489 /*
 490  * bad_mode handles the impossible case in the vectors.  If you see one of
 491  * these, then it's extremely serious, and could mean you have buggy hardware.
 492  * It never returns, and never tries to sync.  We hope that we can at least
 493  * dump out some state information...
 494  */
 495 asmlinkage void bad_mode(struct pt_regs *regs, int reason)
 496 {
 497         console_verbose();
 498
 499         pr_crit("Bad mode in %s handler detected\n", handler[reason]);
 500
 501         die("Oops - bad mode", regs, 0);
 502         local_irq_disable();
 503         panic("bad mode");
 504 }
 505
 506 static int bad_syscall(int n, struct pt_regs *regs)
 507 {
 508         siginfo_t info;
 509
 510         if ((current->personality & PER_MASK) != PER_LINUX) {
 511                 send_sig(SIGSEGV, current, 1);
 512                 return regs->ARM_r0;
 513         }
 514
 515 #ifdef CONFIG_DEBUG_USER
 516         if (user_debug & UDBG_SYSCALL) {
 517                 pr_err("[%d] %s: obsolete system call %08x.\n",
 518                         task_pid_nr(current), current->comm, n);
 519                 dump_instr(KERN_ERR, regs);
 520         }
 521 #endif
 522
 523         info.si_signo = SIGILL;
 524         info.si_errno = 0;
 525         info.si_code  = ILL_ILLTRP;
 526         info.si_addr  = (void __user *)instruction_pointer(regs) -
 527                          (thumb_mode(regs) ? 2 : 4);
 528
 529         arm_notify_die("Oops - bad syscall", regs, &info, n, 0);
 530
 531         return regs->ARM_r0;
 532 }
 533
 534 static inline int
 535 __do_cache_op(unsigned long start, unsigned long end)
 536 {
 537         int ret;
 538
 539         do {
 540                 unsigned long chunk = min(PAGE_SIZE, end - start);
 541
 542                 if (fatal_signal_pending(current))
 543                         return 0;
 544
 545                 ret = flush_cache_user_range(start, start + chunk);
 546                 if (ret)
 547                         return ret;
 548
 549                 cond_resched();
 550                 start += chunk;
 551         } while (start < end);
 552
 553         return 0;
 554 }
 555
 556 static inline int
 557 do_cache_op(unsigned long start, unsigned long end, int flags)
 558 {
 559         if (end < start || flags)
 560                 return -EINVAL;
 561
 562         if (!access_ok(VERIFY_READ, start, end - start))
 563                 return -EFAULT;
 564
 565         return __do_cache_op(start, end);
 566 }
 567
 568 /*
 569  * Handle all unrecognised system calls.
 570  *  0x9f0000 - 0x9fffff are some more esoteric system calls
 571  */
 572 #define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
 573 asmlinkage int arm_syscall(int no, struct pt_regs *regs)
 574 {
 575         siginfo_t info;
 576
 577         if ((no >> 16) != (__ARM_NR_BASE>> 16))
 578                 return bad_syscall(no, regs);
 579
 580         switch (no & 0xffff) {
 581         case 0: /* branch through 0 */
 582                 info.si_signo = SIGSEGV;
 583                 info.si_errno = 0;
 584                 info.si_code  = SEGV_MAPERR;
 585                 info.si_addr  = NULL;
 586
 587                 arm_notify_die("branch through zero", regs, &info, 0, 0);
 588                 return 0;
 589
 590         case NR(breakpoint): /* SWI BREAK_POINT */
 591                 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
 592                 ptrace_break(current, regs);
 593                 return regs->ARM_r0;
 594
 595         /*
 596          * Flush a region from virtual address 'r0' to virtual address 'r1'
 597          * _exclusive_.  There is no alignment requirement on either address;
 598          * user space does not need to know the hardware cache layout.
 599          *
 600          * r2 contains flags.  It should ALWAYS be passed as ZERO until it
 601          * is defined to be something else.  For now we ignore it, but may
 602          * the fires of hell burn in your belly if you break this rule. ;)
 603          *
 604          * (at a later date, we may want to allow this call to not flush
 605          * various aspects of the cache.  Passing '0' will guarantee that
 606          * everything necessary gets flushed to maintain consistency in
 607          * the specified region).
 608          */
 609         case NR(cacheflush):
 610                 return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
 611
 612         case NR(usr26):
 613                 if (!(elf_hwcap & HWCAP_26BIT))
 614                         break;
 615                 regs->ARM_cpsr &= ~MODE32_BIT;
 616                 return regs->ARM_r0;
 617
 618         case NR(usr32):
 619                 if (!(elf_hwcap & HWCAP_26BIT))
 620                         break;
 621                 regs->ARM_cpsr |= MODE32_BIT;
 622                 return regs->ARM_r0;
 623
 624         case NR(set_tls):
 625                 set_tls(regs->ARM_r0);
 626                 return 0;
 627
 628 #ifdef CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG
 629         /*
 630          * Atomically store r1 in *r2 if *r2 is equal to r0 for user space.
 631          * Return zero in r0 if *MEM was changed or non-zero if no exchange
 632          * happened.  Also set the user C flag accordingly.
 633          * If access permissions have to be fixed up then non-zero is
 634          * returned and the operation has to be re-attempted.
 635          *
 636          * *NOTE*: This is a ghost syscall private to the kernel.  Only the
 637          * __kuser_cmpxchg code in entry-armv.S should be aware of its
 638          * existence.  Don't ever use this from user code.
 639          */
 640         case NR(cmpxchg):
 641         for (;;) {
 642                 extern void do_DataAbort(unsigned long addr, unsigned int fsr,
 643                                          struct pt_regs *regs);
 644                 unsigned long val;
 645                 unsigned long addr = regs->ARM_r2;
 646                 struct mm_struct *mm = current->mm;
 647                 pgd_t *pgd; pmd_t *pmd; pte_t *pte;
 648                 spinlock_t *ptl;
 649
 650                 regs->ARM_cpsr &= ~PSR_C_BIT;
 651                 down_read(&mm->mmap_sem);
 652                 pgd = pgd_offset(mm, addr);
 653                 if (!pgd_present(*pgd))
 654                         goto bad_access;
 655                 pmd = pmd_offset(pgd, addr);
 656                 if (!pmd_present(*pmd))
 657                         goto bad_access;
 658                 pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
 659                 if (!pte_present(*pte) || !pte_write(*pte) || !pte_dirty(*pte)) {
 660                         pte_unmap_unlock(pte, ptl);
 661                         goto bad_access;
 662                 }
 663                 val = *(unsigned long *)addr;
 664                 val -= regs->ARM_r0;
 665                 if (val == 0) {
 666                         *(unsigned long *)addr = regs->ARM_r1;
 667                         regs->ARM_cpsr |= PSR_C_BIT;
 668                 }
 669                 pte_unmap_unlock(pte, ptl);
 670                 up_read(&mm->mmap_sem);
 671                 return val;
 672
 673                 bad_access:
 674                 up_read(&mm->mmap_sem);
 675                 /* simulate a write access fault */
 676                 do_DataAbort(addr, 15 + (1 << 11), regs);
 677         }
 678 #endif
 679
 680         default:
 681                 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS
 682                    if not implemented, rather than raising SIGILL.  This
 683                    way the calling program can gracefully determine whether
 684                    a feature is supported.  */
 685                 if ((no & 0xffff) <= 0x7ff)
 686                         return -ENOSYS;
 687                 break;
 688         }
 689 #ifdef CONFIG_DEBUG_USER
 690         /*
 691          * experience shows that these seem to indicate that
 692          * something catastrophic has happened
 693          */
 694         if (user_debug & UDBG_SYSCALL) {
 695                 pr_err("[%d] %s: arm syscall %d\n",
 696                        task_pid_nr(current), current->comm, no);
 697                 dump_instr("", regs);
 698                 if (user_mode(regs)) {
 699                         __show_regs(regs);
 700                         c_backtrace(frame_pointer(regs), processor_mode(regs));
 701                 }
 702         }
 703 #endif
 704         info.si_signo = SIGILL;
 705         info.si_errno = 0;
 706         info.si_code  = ILL_ILLTRP;
 707         info.si_addr  = (void __user *)instruction_pointer(regs) -
 708                          (thumb_mode(regs) ? 2 : 4);
 709
 710         arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0);
 711         return 0;
 712 }
 713
 714 #ifdef CONFIG_TLS_REG_EMUL
 715
 716 /*
 717  * We might be running on an ARMv6+ processor which should have the TLS
 718  * register but for some reason we can't use it, or maybe an SMP system
 719  * using a pre-ARMv6 processor (there are apparently a few prototypes like
 720  * that in existence) and therefore access to that register must be
 721  * emulated.
 722  */
 723
 724 static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
 725 {
 726         int reg = (instr >> 12) & 15;
 727         if (reg == 15)
 728                 return 1;
 729         regs->uregs[reg] = current_thread_info()->tp_value[0];
 730         regs->ARM_pc += 4;
 731         return 0;
 732 }
 733
 734 static struct undef_hook arm_mrc_hook = {
 735         .instr_mask     = 0x0fff0fff,
 736         .instr_val      = 0x0e1d0f70,
 737         .cpsr_mask      = PSR_T_BIT,
 738         .cpsr_val       = 0,
 739         .fn             = get_tp_trap,
 740 };
 741
 742 static int __init arm_mrc_hook_init(void)
 743 {
 744         register_undef_hook(&arm_mrc_hook);
 745         return 0;
 746 }
 747
 748 late_initcall(arm_mrc_hook_init);
 749
 750 #endif
 751
 752 void __bad_xchg(volatile void *ptr, int size)
 753 {
 754         pr_err("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n",
 755                __builtin_return_address(0), ptr, size);
 756         BUG();
 757 }
 758 EXPORT_SYMBOL(__bad_xchg);
 759
 760 /*
 761  * A data abort trap was taken, but we did not handle the instruction.
 762  * Try to abort the user program, or panic if it was the kernel.
 763  */
 764 asmlinkage void
 765 baddataabort(int code, unsigned long instr, struct pt_regs *regs)
 766 {
 767         unsigned long addr = instruction_pointer(regs);
 768         siginfo_t info;
 769
 770 #ifdef CONFIG_DEBUG_USER
 771         if (user_debug & UDBG_BADABORT) {
 772                 pr_err("[%d] %s: bad data abort: code %d instr 0x%08lx\n",
 773                        task_pid_nr(current), current->comm, code, instr);
 774                 dump_instr(KERN_ERR, regs);
 775                 show_pte(current->mm, addr);
 776         }
 777 #endif
 778
 779         info.si_signo = SIGILL;
 780         info.si_errno = 0;
 781         info.si_code  = ILL_ILLOPC;
 782         info.si_addr  = (void __user *)addr;
 783
 784         arm_notify_die("unknown data abort code", regs, &info, instr, 0);
 785 }
 786
 787 void __readwrite_bug(const char *fn)
 788 {
 789         pr_err("%s called, but not implemented\n", fn);
 790         BUG();
 791 }
 792 EXPORT_SYMBOL(__readwrite_bug);
 793
 794 void __pte_error(const char *file, int line, pte_t pte)
 795 {
 796         pr_err("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte));
 797 }
 798
 799 void __pmd_error(const char *file, int line, pmd_t pmd)
 800 {
 801         pr_err("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd));
 802 }
 803
 804 void __pgd_error(const char *file, int line, pgd_t pgd)
 805 {
 806         pr_err("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd));
 807 }
 808
 809 asmlinkage void __div0(void)
 810 {
 811         pr_err("Division by zero in kernel.\n");
 812         dump_stack();
 813 }
 814 EXPORT_SYMBOL(__div0);
 815
 816 void abort(void)
 817 {
 818         BUG();
 819
 820         /* if that doesn't kill us, halt */
 821         panic("Oops failed to kill thread");
 822 }
 823 EXPORT_SYMBOL(abort);
 824
 825 void __init trap_init(void)
 826 {
 827         return;
 828 }
 829
 830 #ifdef CONFIG_KUSER_HELPERS
 831 static void __init kuser_init(void *vectors)
 832 {
 833         extern char __kuser_helper_start[], __kuser_helper_end[];
 834         int kuser_sz = __kuser_helper_end - __kuser_helper_start;
 835
 836         memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
 837
 838         /*
 839          * vectors + 0xfe0 = __kuser_get_tls
 840          * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8
 841          */
 842         if (tls_emu || has_tls_reg)
 843                 memcpy(vectors + 0xfe0, vectors + 0xfe8, 4);
 844 }
 845 #else
 846 static inline void __init kuser_init(void *vectors)
 847 {
 848 }
 849 #endif
 850
 851 void __init early_trap_init(void *vectors_base)
 852 {
 853 #ifndef CONFIG_CPU_V7M
 854         unsigned long vectors = (unsigned long)vectors_base;
 855         extern char __stubs_start[], __stubs_end[];
 856         extern char __vectors_start[], __vectors_end[];
 857         unsigned i;
 858
 859         vectors_page = vectors_base;
 860
 861         /*
 862          * Poison the vectors page with an undefined instruction.  This
 863          * instruction is chosen to be undefined for both ARM and Thumb
 864          * ISAs.  The Thumb version is an undefined instruction with a
 865          * branch back to the undefined instruction.
 866          */
 867         for (i = 0; i < PAGE_SIZE / sizeof(u32); i++)
 868                 ((u32 *)vectors_base)[i] = 0xe7fddef1;
 869
 870         /*
 871          * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
 872          * into the vector page, mapped at 0xffff0000, and ensure these
 873          * are visible to the instruction stream.
 874          */
 875         memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
 876         memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start);
 877
 878         kuser_init(vectors_base);
 879
 880         flush_icache_range(vectors, vectors + PAGE_SIZE * 2);
 881         modify_domain(DOMAIN_USER, DOMAIN_CLIENT);
 882 #else /* ifndef CONFIG_CPU_V7M */
 883         /*
 884          * on V7-M there is no need to copy the vector table to a dedicated
 885          * memory area. The address is configurable and so a table in the kernel
 886          * image can be used.
 887          */
 888 #endif
 889 }