linux/arch/arm/kernel/traps.c
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   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/delay.h>
  25#include <linux/init.h>
  26#include <linux/sched.h>
  27
  28#include <linux/atomic.h>
  29#include <asm/cacheflush.h>
  30#include <asm/system.h>
  31#include <asm/unistd.h>
  32#include <asm/traps.h>
  33#include <asm/unwind.h>
  34#include <asm/tls.h>
  35
  36#include "signal.h"
  37
  38static const char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" };
  39
  40void *vectors_page;
  41
  42#ifdef CONFIG_DEBUG_USER
  43unsigned int user_debug;
  44
  45static int __init user_debug_setup(char *str)
  46{
  47        get_option(&str, &user_debug);
  48        return 1;
  49}
  50__setup("user_debug=", user_debug_setup);
  51#endif
  52
  53static void dump_mem(const char *, const char *, unsigned long, unsigned long);
  54
  55void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame)
  56{
  57#ifdef CONFIG_KALLSYMS
  58        printk("[<%08lx>] (%pS) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from);
  59#else
  60        printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
  61#endif
  62
  63        if (in_exception_text(where))
  64                dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs));
  65}
  66
  67#ifndef CONFIG_ARM_UNWIND
  68/*
  69 * Stack pointers should always be within the kernels view of
  70 * physical memory.  If it is not there, then we can't dump
  71 * out any information relating to the stack.
  72 */
  73static int verify_stack(unsigned long sp)
  74{
  75        if (sp < PAGE_OFFSET ||
  76            (sp > (unsigned long)high_memory && high_memory != NULL))
  77                return -EFAULT;
  78
  79        return 0;
  80}
  81#endif
  82
  83/*
  84 * Dump out the contents of some memory nicely...
  85 */
  86static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
  87                     unsigned long top)
  88{
  89        unsigned long first;
  90        mm_segment_t fs;
  91        int i;
  92
  93        /*
  94         * We need to switch to kernel mode so that we can use __get_user
  95         * to safely read from kernel space.  Note that we now dump the
  96         * code first, just in case the backtrace kills us.
  97         */
  98        fs = get_fs();
  99        set_fs(KERNEL_DS);
 100
 101        printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top);
 102
 103        for (first = bottom & ~31; first < top; first += 32) {
 104                unsigned long p;
 105                char str[sizeof(" 12345678") * 8 + 1];
 106
 107                memset(str, ' ', sizeof(str));
 108                str[sizeof(str) - 1] = '\0';
 109
 110                for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
 111                        if (p >= bottom && p < top) {
 112                                unsigned long val;
 113                                if (__get_user(val, (unsigned long *)p) == 0)
 114                                        sprintf(str + i * 9, " %08lx", val);
 115                                else
 116                                        sprintf(str + i * 9, " ????????");
 117                        }
 118                }
 119                printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
 120        }
 121
 122        set_fs(fs);
 123}
 124
 125static void dump_instr(const char *lvl, struct pt_regs *regs)
 126{
 127        unsigned long addr = instruction_pointer(regs);
 128        const int thumb = thumb_mode(regs);
 129        const int width = thumb ? 4 : 8;
 130        mm_segment_t fs;
 131        char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
 132        int i;
 133
 134        /*
 135         * We need to switch to kernel mode so that we can use __get_user
 136         * to safely read from kernel space.  Note that we now dump the
 137         * code first, just in case the backtrace kills us.
 138         */
 139        fs = get_fs();
 140        set_fs(KERNEL_DS);
 141
 142        for (i = -4; i < 1 + !!thumb; i++) {
 143                unsigned int val, bad;
 144
 145                if (thumb)
 146                        bad = __get_user(val, &((u16 *)addr)[i]);
 147                else
 148                        bad = __get_user(val, &((u32 *)addr)[i]);
 149
 150                if (!bad)
 151                        p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ",
 152                                        width, val);
 153                else {
 154                        p += sprintf(p, "bad PC value");
 155                        break;
 156                }
 157        }
 158        printk("%sCode: %s\n", lvl, str);
 159
 160        set_fs(fs);
 161}
 162
 163#ifdef CONFIG_ARM_UNWIND
 164static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 165{
 166        unwind_backtrace(regs, tsk);
 167}
 168#else
 169static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 170{
 171        unsigned int fp, mode;
 172        int ok = 1;
 173
 174        printk("Backtrace: ");
 175
 176        if (!tsk)
 177                tsk = current;
 178
 179        if (regs) {
 180                fp = regs->ARM_fp;
 181                mode = processor_mode(regs);
 182        } else if (tsk != current) {
 183                fp = thread_saved_fp(tsk);
 184                mode = 0x10;
 185        } else {
 186                asm("mov %0, fp" : "=r" (fp) : : "cc");
 187                mode = 0x10;
 188        }
 189
 190        if (!fp) {
 191                printk("no frame pointer");
 192                ok = 0;
 193        } else if (verify_stack(fp)) {
 194                printk("invalid frame pointer 0x%08x", fp);
 195                ok = 0;
 196        } else if (fp < (unsigned long)end_of_stack(tsk))
 197                printk("frame pointer underflow");
 198        printk("\n");
 199
 200        if (ok)
 201                c_backtrace(fp, mode);
 202}
 203#endif
 204
 205void dump_stack(void)
 206{
 207        dump_backtrace(NULL, NULL);
 208}
 209
 210EXPORT_SYMBOL(dump_stack);
 211
 212void show_stack(struct task_struct *tsk, unsigned long *sp)
 213{
 214        dump_backtrace(NULL, tsk);
 215        barrier();
 216}
 217
 218#ifdef CONFIG_PREEMPT
 219#define S_PREEMPT " PREEMPT"
 220#else
 221#define S_PREEMPT ""
 222#endif
 223#ifdef CONFIG_SMP
 224#define S_SMP " SMP"
 225#else
 226#define S_SMP ""
 227#endif
 228
 229static int __die(const char *str, int err, struct thread_info *thread, struct pt_regs *regs)
 230{
 231        struct task_struct *tsk = thread->task;
 232        static int die_counter;
 233        int ret;
 234
 235        printk(KERN_EMERG "Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
 236               str, err, ++die_counter);
 237
 238        /* trap and error numbers are mostly meaningless on ARM */
 239        ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV);
 240        if (ret == NOTIFY_STOP)
 241                return ret;
 242
 243        print_modules();
 244        __show_regs(regs);
 245        printk(KERN_EMERG "Process %.*s (pid: %d, stack limit = 0x%p)\n",
 246                TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1);
 247
 248        if (!user_mode(regs) || in_interrupt()) {
 249                dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp,
 250                         THREAD_SIZE + (unsigned long)task_stack_page(tsk));
 251                dump_backtrace(regs, tsk);
 252                dump_instr(KERN_EMERG, regs);
 253        }
 254
 255        return ret;
 256}
 257
 258static DEFINE_SPINLOCK(die_lock);
 259
 260/*
 261 * This function is protected against re-entrancy.
 262 */
 263void die(const char *str, struct pt_regs *regs, int err)
 264{
 265        struct thread_info *thread = current_thread_info();
 266        int ret;
 267
 268        oops_enter();
 269
 270        spin_lock_irq(&die_lock);
 271        console_verbose();
 272        bust_spinlocks(1);
 273        ret = __die(str, err, thread, regs);
 274
 275        if (regs && kexec_should_crash(thread->task))
 276                crash_kexec(regs);
 277
 278        bust_spinlocks(0);
 279        add_taint(TAINT_DIE);
 280        spin_unlock_irq(&die_lock);
 281        oops_exit();
 282
 283        if (in_interrupt())
 284                panic("Fatal exception in interrupt");
 285        if (panic_on_oops)
 286                panic("Fatal exception");
 287        if (ret != NOTIFY_STOP)
 288                do_exit(SIGSEGV);
 289}
 290
 291void arm_notify_die(const char *str, struct pt_regs *regs,
 292                struct siginfo *info, unsigned long err, unsigned long trap)
 293{
 294        if (user_mode(regs)) {
 295                current->thread.error_code = err;
 296                current->thread.trap_no = trap;
 297
 298                force_sig_info(info->si_signo, info, current);
 299        } else {
 300                die(str, regs, err);
 301        }
 302}
 303
 304static LIST_HEAD(undef_hook);
 305static DEFINE_SPINLOCK(undef_lock);
 306
 307void register_undef_hook(struct undef_hook *hook)
 308{
 309        unsigned long flags;
 310
 311        spin_lock_irqsave(&undef_lock, flags);
 312        list_add(&hook->node, &undef_hook);
 313        spin_unlock_irqrestore(&undef_lock, flags);
 314}
 315
 316void unregister_undef_hook(struct undef_hook *hook)
 317{
 318        unsigned long flags;
 319
 320        spin_lock_irqsave(&undef_lock, flags);
 321        list_del(&hook->node);
 322        spin_unlock_irqrestore(&undef_lock, flags);
 323}
 324
 325static int call_undef_hook(struct pt_regs *regs, unsigned int instr)
 326{
 327        struct undef_hook *hook;
 328        unsigned long flags;
 329        int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL;
 330
 331        spin_lock_irqsave(&undef_lock, flags);
 332        list_for_each_entry(hook, &undef_hook, node)
 333                if ((instr & hook->instr_mask) == hook->instr_val &&
 334                    (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val)
 335                        fn = hook->fn;
 336        spin_unlock_irqrestore(&undef_lock, flags);
 337
 338        return fn ? fn(regs, instr) : 1;
 339}
 340
 341asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
 342{
 343        unsigned int correction = thumb_mode(regs) ? 2 : 4;
 344        unsigned int instr;
 345        siginfo_t info;
 346        void __user *pc;
 347
 348        /*
 349         * According to the ARM ARM, PC is 2 or 4 bytes ahead,
 350         * depending whether we're in Thumb mode or not.
 351         * Correct this offset.
 352         */
 353        regs->ARM_pc -= correction;
 354
 355        pc = (void __user *)instruction_pointer(regs);
 356
 357        if (processor_mode(regs) == SVC_MODE) {
 358#ifdef CONFIG_THUMB2_KERNEL
 359                if (thumb_mode(regs)) {
 360                        instr = ((u16 *)pc)[0];
 361                        if (is_wide_instruction(instr)) {
 362                                instr <<= 16;
 363                                instr |= ((u16 *)pc)[1];
 364                        }
 365                } else
 366#endif
 367                        instr = *(u32 *) pc;
 368        } else if (thumb_mode(regs)) {
 369                get_user(instr, (u16 __user *)pc);
 370                if (is_wide_instruction(instr)) {
 371                        unsigned int instr2;
 372                        get_user(instr2, (u16 __user *)pc+1);
 373                        instr <<= 16;
 374                        instr |= instr2;
 375                }
 376        } else {
 377                get_user(instr, (u32 __user *)pc);
 378        }
 379
 380        if (call_undef_hook(regs, instr) == 0)
 381                return;
 382
 383#ifdef CONFIG_DEBUG_USER
 384        if (user_debug & UDBG_UNDEFINED) {
 385                printk(KERN_INFO "%s (%d): undefined instruction: pc=%p\n",
 386                        current->comm, task_pid_nr(current), pc);
 387                dump_instr(KERN_INFO, regs);
 388        }
 389#endif
 390
 391        info.si_signo = SIGILL;
 392        info.si_errno = 0;
 393        info.si_code  = ILL_ILLOPC;
 394        info.si_addr  = pc;
 395
 396        arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6);
 397}
 398
 399asmlinkage void do_unexp_fiq (struct pt_regs *regs)
 400{
 401        printk("Hmm.  Unexpected FIQ received, but trying to continue\n");
 402        printk("You may have a hardware problem...\n");
 403}
 404
 405/*
 406 * bad_mode handles the impossible case in the vectors.  If you see one of
 407 * these, then it's extremely serious, and could mean you have buggy hardware.
 408 * It never returns, and never tries to sync.  We hope that we can at least
 409 * dump out some state information...
 410 */
 411asmlinkage void bad_mode(struct pt_regs *regs, int reason)
 412{
 413        console_verbose();
 414
 415        printk(KERN_CRIT "Bad mode in %s handler detected\n", handler[reason]);
 416
 417        die("Oops - bad mode", regs, 0);
 418        local_irq_disable();
 419        panic("bad mode");
 420}
 421
 422static int bad_syscall(int n, struct pt_regs *regs)
 423{
 424        struct thread_info *thread = current_thread_info();
 425        siginfo_t info;
 426
 427        if ((current->personality & PER_MASK) != PER_LINUX &&
 428            thread->exec_domain->handler) {
 429                thread->exec_domain->handler(n, regs);
 430                return regs->ARM_r0;
 431        }
 432
 433#ifdef CONFIG_DEBUG_USER
 434        if (user_debug & UDBG_SYSCALL) {
 435                printk(KERN_ERR "[%d] %s: obsolete system call %08x.\n",
 436                        task_pid_nr(current), current->comm, n);
 437                dump_instr(KERN_ERR, regs);
 438        }
 439#endif
 440
 441        info.si_signo = SIGILL;
 442        info.si_errno = 0;
 443        info.si_code  = ILL_ILLTRP;
 444        info.si_addr  = (void __user *)instruction_pointer(regs) -
 445                         (thumb_mode(regs) ? 2 : 4);
 446
 447        arm_notify_die("Oops - bad syscall", regs, &info, n, 0);
 448
 449        return regs->ARM_r0;
 450}
 451
 452static inline void
 453do_cache_op(unsigned long start, unsigned long end, int flags)
 454{
 455        struct mm_struct *mm = current->active_mm;
 456        struct vm_area_struct *vma;
 457
 458        if (end < start || flags)
 459                return;
 460
 461        down_read(&mm->mmap_sem);
 462        vma = find_vma(mm, start);
 463        if (vma && vma->vm_start < end) {
 464                if (start < vma->vm_start)
 465                        start = vma->vm_start;
 466                if (end > vma->vm_end)
 467                        end = vma->vm_end;
 468
 469                flush_cache_user_range(vma, start, end);
 470        }
 471        up_read(&mm->mmap_sem);
 472}
 473
 474/*
 475 * Handle all unrecognised system calls.
 476 *  0x9f0000 - 0x9fffff are some more esoteric system calls
 477 */
 478#define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
 479asmlinkage int arm_syscall(int no, struct pt_regs *regs)
 480{
 481        struct thread_info *thread = current_thread_info();
 482        siginfo_t info;
 483
 484        if ((no >> 16) != (__ARM_NR_BASE>> 16))
 485                return bad_syscall(no, regs);
 486
 487        switch (no & 0xffff) {
 488        case 0: /* branch through 0 */
 489                info.si_signo = SIGSEGV;
 490                info.si_errno = 0;
 491                info.si_code  = SEGV_MAPERR;
 492                info.si_addr  = NULL;
 493
 494                arm_notify_die("branch through zero", regs, &info, 0, 0);
 495                return 0;
 496
 497        case NR(breakpoint): /* SWI BREAK_POINT */
 498                regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
 499                ptrace_break(current, regs);
 500                return regs->ARM_r0;
 501
 502        /*
 503         * Flush a region from virtual address 'r0' to virtual address 'r1'
 504         * _exclusive_.  There is no alignment requirement on either address;
 505         * user space does not need to know the hardware cache layout.
 506         *
 507         * r2 contains flags.  It should ALWAYS be passed as ZERO until it
 508         * is defined to be something else.  For now we ignore it, but may
 509         * the fires of hell burn in your belly if you break this rule. ;)
 510         *
 511         * (at a later date, we may want to allow this call to not flush
 512         * various aspects of the cache.  Passing '0' will guarantee that
 513         * everything necessary gets flushed to maintain consistency in
 514         * the specified region).
 515         */
 516        case NR(cacheflush):
 517                do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
 518                return 0;
 519
 520        case NR(usr26):
 521                if (!(elf_hwcap & HWCAP_26BIT))
 522                        break;
 523                regs->ARM_cpsr &= ~MODE32_BIT;
 524                return regs->ARM_r0;
 525
 526        case NR(usr32):
 527                if (!(elf_hwcap & HWCAP_26BIT))
 528                        break;
 529                regs->ARM_cpsr |= MODE32_BIT;
 530                return regs->ARM_r0;
 531
 532        case NR(set_tls):
 533                thread->tp_value = regs->ARM_r0;
 534                if (tls_emu)
 535                        return 0;
 536                if (has_tls_reg) {
 537                        asm ("mcr p15, 0, %0, c13, c0, 3"
 538                                : : "r" (regs->ARM_r0));
 539                } else {
 540                        /*
 541                         * User space must never try to access this directly.
 542                         * Expect your app to break eventually if you do so.
 543                         * The user helper at 0xffff0fe0 must be used instead.
 544                         * (see entry-armv.S for details)
 545                         */
 546                        *((unsigned int *)0xffff0ff0) = regs->ARM_r0;
 547                }
 548                return 0;
 549
 550#ifdef CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG
 551        /*
 552         * Atomically store r1 in *r2 if *r2 is equal to r0 for user space.
 553         * Return zero in r0 if *MEM was changed or non-zero if no exchange
 554         * happened.  Also set the user C flag accordingly.
 555         * If access permissions have to be fixed up then non-zero is
 556         * returned and the operation has to be re-attempted.
 557         *
 558         * *NOTE*: This is a ghost syscall private to the kernel.  Only the
 559         * __kuser_cmpxchg code in entry-armv.S should be aware of its
 560         * existence.  Don't ever use this from user code.
 561         */
 562        case NR(cmpxchg):
 563        for (;;) {
 564                extern void do_DataAbort(unsigned long addr, unsigned int fsr,
 565                                         struct pt_regs *regs);
 566                unsigned long val;
 567                unsigned long addr = regs->ARM_r2;
 568                struct mm_struct *mm = current->mm;
 569                pgd_t *pgd; pmd_t *pmd; pte_t *pte;
 570                spinlock_t *ptl;
 571
 572                regs->ARM_cpsr &= ~PSR_C_BIT;
 573                down_read(&mm->mmap_sem);
 574                pgd = pgd_offset(mm, addr);
 575                if (!pgd_present(*pgd))
 576                        goto bad_access;
 577                pmd = pmd_offset(pgd, addr);
 578                if (!pmd_present(*pmd))
 579                        goto bad_access;
 580                pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
 581                if (!pte_present(*pte) || !pte_write(*pte) || !pte_dirty(*pte)) {
 582                        pte_unmap_unlock(pte, ptl);
 583                        goto bad_access;
 584                }
 585                val = *(unsigned long *)addr;
 586                val -= regs->ARM_r0;
 587                if (val == 0) {
 588                        *(unsigned long *)addr = regs->ARM_r1;
 589                        regs->ARM_cpsr |= PSR_C_BIT;
 590                }
 591                pte_unmap_unlock(pte, ptl);
 592                up_read(&mm->mmap_sem);
 593                return val;
 594
 595                bad_access:
 596                up_read(&mm->mmap_sem);
 597                /* simulate a write access fault */
 598                do_DataAbort(addr, 15 + (1 << 11), regs);
 599        }
 600#endif
 601
 602        default:
 603                /* Calls 9f00xx..9f07ff are defined to return -ENOSYS
 604                   if not implemented, rather than raising SIGILL.  This
 605                   way the calling program can gracefully determine whether
 606                   a feature is supported.  */
 607                if ((no & 0xffff) <= 0x7ff)
 608                        return -ENOSYS;
 609                break;
 610        }
 611#ifdef CONFIG_DEBUG_USER
 612        /*
 613         * experience shows that these seem to indicate that
 614         * something catastrophic has happened
 615         */
 616        if (user_debug & UDBG_SYSCALL) {
 617                printk("[%d] %s: arm syscall %d\n",
 618                       task_pid_nr(current), current->comm, no);
 619                dump_instr("", regs);
 620                if (user_mode(regs)) {
 621                        __show_regs(regs);
 622                        c_backtrace(regs->ARM_fp, processor_mode(regs));
 623                }
 624        }
 625#endif
 626        info.si_signo = SIGILL;
 627        info.si_errno = 0;
 628        info.si_code  = ILL_ILLTRP;
 629        info.si_addr  = (void __user *)instruction_pointer(regs) -
 630                         (thumb_mode(regs) ? 2 : 4);
 631
 632        arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0);
 633        return 0;
 634}
 635
 636#ifdef CONFIG_TLS_REG_EMUL
 637
 638/*
 639 * We might be running on an ARMv6+ processor which should have the TLS
 640 * register but for some reason we can't use it, or maybe an SMP system
 641 * using a pre-ARMv6 processor (there are apparently a few prototypes like
 642 * that in existence) and therefore access to that register must be
 643 * emulated.
 644 */
 645
 646static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
 647{
 648        int reg = (instr >> 12) & 15;
 649        if (reg == 15)
 650                return 1;
 651        regs->uregs[reg] = current_thread_info()->tp_value;
 652        regs->ARM_pc += 4;
 653        return 0;
 654}
 655
 656static struct undef_hook arm_mrc_hook = {
 657        .instr_mask     = 0x0fff0fff,
 658        .instr_val      = 0x0e1d0f70,
 659        .cpsr_mask      = PSR_T_BIT,
 660        .cpsr_val       = 0,
 661        .fn             = get_tp_trap,
 662};
 663
 664static int __init arm_mrc_hook_init(void)
 665{
 666        register_undef_hook(&arm_mrc_hook);
 667        return 0;
 668}
 669
 670late_initcall(arm_mrc_hook_init);
 671
 672#endif
 673
 674void __bad_xchg(volatile void *ptr, int size)
 675{
 676        printk("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n",
 677                __builtin_return_address(0), ptr, size);
 678        BUG();
 679}
 680EXPORT_SYMBOL(__bad_xchg);
 681
 682/*
 683 * A data abort trap was taken, but we did not handle the instruction.
 684 * Try to abort the user program, or panic if it was the kernel.
 685 */
 686asmlinkage void
 687baddataabort(int code, unsigned long instr, struct pt_regs *regs)
 688{
 689        unsigned long addr = instruction_pointer(regs);
 690        siginfo_t info;
 691
 692#ifdef CONFIG_DEBUG_USER
 693        if (user_debug & UDBG_BADABORT) {
 694                printk(KERN_ERR "[%d] %s: bad data abort: code %d instr 0x%08lx\n",
 695                        task_pid_nr(current), current->comm, code, instr);
 696                dump_instr(KERN_ERR, regs);
 697                show_pte(current->mm, addr);
 698        }
 699#endif
 700
 701        info.si_signo = SIGILL;
 702        info.si_errno = 0;
 703        info.si_code  = ILL_ILLOPC;
 704        info.si_addr  = (void __user *)addr;
 705
 706        arm_notify_die("unknown data abort code", regs, &info, instr, 0);
 707}
 708
 709void __attribute__((noreturn)) __bug(const char *file, int line)
 710{
 711        printk(KERN_CRIT"kernel BUG at %s:%d!\n", file, line);
 712        *(int *)0 = 0;
 713
 714        /* Avoid "noreturn function does return" */
 715        for (;;);
 716}
 717EXPORT_SYMBOL(__bug);
 718
 719void __readwrite_bug(const char *fn)
 720{
 721        printk("%s called, but not implemented\n", fn);
 722        BUG();
 723}
 724EXPORT_SYMBOL(__readwrite_bug);
 725
 726void __pte_error(const char *file, int line, pte_t pte)
 727{
 728        printk("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte));
 729}
 730
 731void __pmd_error(const char *file, int line, pmd_t pmd)
 732{
 733        printk("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd));
 734}
 735
 736void __pgd_error(const char *file, int line, pgd_t pgd)
 737{
 738        printk("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd));
 739}
 740
 741asmlinkage void __div0(void)
 742{
 743        printk("Division by zero in kernel.\n");
 744        dump_stack();
 745}
 746EXPORT_SYMBOL(__div0);
 747
 748void abort(void)
 749{
 750        BUG();
 751
 752        /* if that doesn't kill us, halt */
 753        panic("Oops failed to kill thread");
 754}
 755EXPORT_SYMBOL(abort);
 756
 757void __init trap_init(void)
 758{
 759        return;
 760}
 761
 762static void __init kuser_get_tls_init(unsigned long vectors)
 763{
 764        /*
 765         * vectors + 0xfe0 = __kuser_get_tls
 766         * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8
 767         */
 768        if (tls_emu || has_tls_reg)
 769                memcpy((void *)vectors + 0xfe0, (void *)vectors + 0xfe8, 4);
 770}
 771
 772void __init early_trap_init(void)
 773{
 774#if defined(CONFIG_CPU_USE_DOMAINS)
 775        unsigned long vectors = CONFIG_VECTORS_BASE;
 776#else
 777        unsigned long vectors = (unsigned long)vectors_page;
 778#endif
 779        extern char __stubs_start[], __stubs_end[];
 780        extern char __vectors_start[], __vectors_end[];
 781        extern char __kuser_helper_start[], __kuser_helper_end[];
 782        int kuser_sz = __kuser_helper_end - __kuser_helper_start;
 783
 784        /*
 785         * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
 786         * into the vector page, mapped at 0xffff0000, and ensure these
 787         * are visible to the instruction stream.
 788         */
 789        memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
 790        memcpy((void *)vectors + 0x200, __stubs_start, __stubs_end - __stubs_start);
 791        memcpy((void *)vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
 792
 793        /*
 794         * Do processor specific fixups for the kuser helpers
 795         */
 796        kuser_get_tls_init(vectors);
 797
 798        /*
 799         * Copy signal return handlers into the vector page, and
 800         * set sigreturn to be a pointer to these.
 801         */
 802        memcpy((void *)(vectors + KERN_SIGRETURN_CODE - CONFIG_VECTORS_BASE),
 803               sigreturn_codes, sizeof(sigreturn_codes));
 804        memcpy((void *)(vectors + KERN_RESTART_CODE - CONFIG_VECTORS_BASE),
 805               syscall_restart_code, sizeof(syscall_restart_code));
 806
 807        flush_icache_range(vectors, vectors + PAGE_SIZE);
 808        modify_domain(DOMAIN_USER, DOMAIN_CLIENT);
 809}
 810
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