arch/arm/mm/fault.c

   1 /*
   2  *  linux/arch/arm/mm/fault.c
   3  *
   4  *  Copyright (C) 1995  Linus Torvalds
   5  *  Modifications for ARM processor (c) 1995-2004 Russell King
   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 #include <linux/module.h>
  12 #include <linux/signal.h>
  13 #include <linux/mm.h>
  14 #include <linux/hardirq.h>
  15 #include <linux/init.h>
  16 #include <linux/kprobes.h>
  17 #include <linux/uaccess.h>
  18 #include <linux/page-flags.h>
  19 #include <linux/sched.h>
  20 #include <linux/highmem.h>
  21 #include <linux/perf_event.h>
  22
  23 #include <asm/system.h>
  24 #include <asm/pgtable.h>
  25 #include <asm/tlbflush.h>
  26
  27 #include "fault.h"
  28
  29 /*
  30  * Fault status register encodings.  We steal bit 31 for our own purposes.
  31  */
  32 #define FSR_LNX_PF              (1 << 31)
  33 #define FSR_WRITE               (1 << 11)
  34 #define FSR_FS4                 (1 << 10)
  35 #define FSR_FS3_0               (15)
  36
  37 static inline int fsr_fs(unsigned int fsr)
  38 {
  39         return (fsr & FSR_FS3_0) | (fsr & FSR_FS4) >> 6;
  40 }
  41
  42 #ifdef CONFIG_MMU
  43
  44 #ifdef CONFIG_KPROBES
  45 static inline int notify_page_fault(struct pt_regs *regs, unsigned int fsr)
  46 {
  47         int ret = 0;
  48
  49         if (!user_mode(regs)) {
  50                 /* kprobe_running() needs smp_processor_id() */
  51                 preempt_disable();
  52                 if (kprobe_running() && kprobe_fault_handler(regs, fsr))
  53                         ret = 1;
  54                 preempt_enable();
  55         }
  56
  57         return ret;
  58 }
  59 #else
  60 static inline int notify_page_fault(struct pt_regs *regs, unsigned int fsr)
  61 {
  62         return 0;
  63 }
  64 #endif
  65
  66 /*
  67  * This is useful to dump out the page tables associated with
  68  * 'addr' in mm 'mm'.
  69  */
  70 void show_pte(struct mm_struct *mm, unsigned long addr)
  71 {
  72         pgd_t *pgd;
  73
  74         if (!mm)
  75                 mm = &init_mm;
  76
  77         printk(KERN_ALERT "pgd = %p\n", mm->pgd);
  78         pgd = pgd_offset(mm, addr);
  79         printk(KERN_ALERT "[%08lx] *pgd=%08llx",
  80                         addr, (long long)pgd_val(*pgd));
  81
  82         do {
  83                 pud_t *pud;
  84                 pmd_t *pmd;
  85                 pte_t *pte;
  86
  87                 if (pgd_none(*pgd))
  88                         break;
  89
  90                 if (pgd_bad(*pgd)) {
  91                         printk("(bad)");
  92                         break;
  93                 }
  94
  95                 pud = pud_offset(pgd, addr);
  96                 if (PTRS_PER_PUD != 1)
  97                         printk(", *pud=%08llx", (long long)pud_val(*pud));
  98
  99                 if (pud_none(*pud))
 100                         break;
 101
 102                 if (pud_bad(*pud)) {
 103                         printk("(bad)");
 104                         break;
 105                 }
 106
 107                 pmd = pmd_offset(pud, addr);
 108                 if (PTRS_PER_PMD != 1)
 109                         printk(", *pmd=%08llx", (long long)pmd_val(*pmd));
 110
 111                 if (pmd_none(*pmd))
 112                         break;
 113
 114                 if (pmd_bad(*pmd)) {
 115                         printk("(bad)");
 116                         break;
 117                 }
 118
 119                 /* We must not map this if we have highmem enabled */
 120                 if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT)))
 121                         break;
 122
 123                 pte = pte_offset_map(pmd, addr);
 124                 printk(", *pte=%08llx", (long long)pte_val(*pte));
 125                 printk(", *ppte=%08llx",
 126                        (long long)pte_val(pte[PTE_HWTABLE_PTRS]));
 127                 pte_unmap(pte);
 128         } while(0);
 129
 130         printk("\n");
 131 }
 132 #else                                   /* CONFIG_MMU */
 133 void show_pte(struct mm_struct *mm, unsigned long addr)
 134 { }
 135 #endif                                  /* CONFIG_MMU */
 136
 137 /*
 138  * Oops.  The kernel tried to access some page that wasn't present.
 139  */
 140 static void
 141 __do_kernel_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
 142                   struct pt_regs *regs)
 143 {
 144         /*
 145          * Are we prepared to handle this kernel fault?
 146          */
 147         if (fixup_exception(regs))
 148                 return;
 149
 150         /*
 151          * No handler, we'll have to terminate things with extreme prejudice.
 152          */
 153         bust_spinlocks(1);
 154         printk(KERN_ALERT
 155                 "Unable to handle kernel %s at virtual address %08lx\n",
 156                 (addr < PAGE_SIZE) ? "NULL pointer dereference" :
 157                 "paging request", addr);
 158
 159         show_pte(mm, addr);
 160         die("Oops", regs, fsr);
 161         bust_spinlocks(0);
 162         do_exit(SIGKILL);
 163 }
 164
 165 /*
 166  * Something tried to access memory that isn't in our memory map..
 167  * User mode accesses just cause a SIGSEGV
 168  */
 169 static void
 170 __do_user_fault(struct task_struct *tsk, unsigned long addr,
 171                 unsigned int fsr, unsigned int sig, int code,
 172                 struct pt_regs *regs)
 173 {
 174         struct siginfo si;
 175
 176 #ifdef CONFIG_DEBUG_USER
 177         if (user_debug & UDBG_SEGV) {
 178                 printk(KERN_DEBUG "%s: unhandled page fault (%d) at 0x%08lx, code 0x%03x\n",
 179                        tsk->comm, sig, addr, fsr);
 180                 show_pte(tsk->mm, addr);
 181                 show_regs(regs);
 182         }
 183 #endif
 184
 185         tsk->thread.address = addr;
 186         tsk->thread.error_code = fsr;
 187         tsk->thread.trap_no = 14;
 188         si.si_signo = sig;
 189         si.si_errno = 0;
 190         si.si_code = code;
 191         si.si_addr = (void __user *)addr;
 192         force_sig_info(sig, &si, tsk);
 193 }
 194
 195 void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 196 {
 197         struct task_struct *tsk = current;
 198         struct mm_struct *mm = tsk->active_mm;
 199
 200         /*
 201          * If we are in kernel mode at this point, we
 202          * have no context to handle this fault with.
 203          */
 204         if (user_mode(regs))
 205                 __do_user_fault(tsk, addr, fsr, SIGSEGV, SEGV_MAPERR, regs);
 206         else
 207                 __do_kernel_fault(mm, addr, fsr, regs);
 208 }
 209
 210 #ifdef CONFIG_MMU
 211 #define VM_FAULT_BADMAP         0x010000
 212 #define VM_FAULT_BADACCESS      0x020000
 213
 214 /*
 215  * Check that the permissions on the VMA allow for the fault which occurred.
 216  * If we encountered a write fault, we must have write permission, otherwise
 217  * we allow any permission.
 218  */
 219 static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma)
 220 {
 221         unsigned int mask = VM_READ | VM_WRITE | VM_EXEC;
 222
 223         if (fsr & FSR_WRITE)
 224                 mask = VM_WRITE;
 225         if (fsr & FSR_LNX_PF)
 226                 mask = VM_EXEC;
 227
 228         return vma->vm_flags & mask ? false : true;
 229 }
 230
 231 static int __kprobes
 232 __do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
 233                 struct task_struct *tsk)
 234 {
 235         struct vm_area_struct *vma;
 236         int fault;
 237
 238         vma = find_vma(mm, addr);
 239         fault = VM_FAULT_BADMAP;
 240         if (unlikely(!vma))
 241                 goto out;
 242         if (unlikely(vma->vm_start > addr))
 243                 goto check_stack;
 244
 245         /*
 246          * Ok, we have a good vm_area for this
 247          * memory access, so we can handle it.
 248          */
 249 good_area:
 250         if (access_error(fsr, vma)) {
 251                 fault = VM_FAULT_BADACCESS;
 252                 goto out;
 253         }
 254
 255         /*
 256          * If for any reason at all we couldn't handle the fault, make
 257          * sure we exit gracefully rather than endlessly redo the fault.
 258          */
 259         fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, (fsr & FSR_WRITE) ? FAULT_FLAG_WRITE : 0);
 260         if (unlikely(fault & VM_FAULT_ERROR))
 261                 return fault;
 262         if (fault & VM_FAULT_MAJOR)
 263                 tsk->maj_flt++;
 264         else
 265                 tsk->min_flt++;
 266         return fault;
 267
 268 check_stack:
 269         if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
 270                 goto good_area;
 271 out:
 272         return fault;
 273 }
 274
 275 static int __kprobes
 276 do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 277 {
 278         struct task_struct *tsk;
 279         struct mm_struct *mm;
 280         int fault, sig, code;
 281
 282         if (notify_page_fault(regs, fsr))
 283                 return 0;
 284
 285         tsk = current;
 286         mm  = tsk->mm;
 287
 288         /* Enable interrupts if they were enabled in the parent context. */
 289         if (interrupts_enabled(regs))
 290                 local_irq_enable();
 291
 292         /*
 293          * If we're in an interrupt or have no user
 294          * context, we must not take the fault..
 295          */
 296         if (in_atomic() || !mm)
 297                 goto no_context;
 298
 299         /*
 300          * As per x86, we may deadlock here.  However, since the kernel only
 301          * validly references user space from well defined areas of the code,
 302          * we can bug out early if this is from code which shouldn't.
 303          */
 304         if (!down_read_trylock(&mm->mmap_sem)) {
 305                 if (!user_mode(regs) && !search_exception_tables(regs->ARM_pc))
 306                         goto no_context;
 307                 down_read(&mm->mmap_sem);
 308         } else {
 309                 /*
 310                  * The above down_read_trylock() might have succeeded in
 311                  * which case, we'll have missed the might_sleep() from
 312                  * down_read()
 313                  */
 314                 might_sleep();
 315 #ifdef CONFIG_DEBUG_VM
 316                 if (!user_mode(regs) &&
 317                     !search_exception_tables(regs->ARM_pc))
 318                         goto no_context;
 319 #endif
 320         }
 321
 322         fault = __do_page_fault(mm, addr, fsr, tsk);
 323         up_read(&mm->mmap_sem);
 324
 325         perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
 326         if (fault & VM_FAULT_MAJOR)
 327                 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, addr);
 328         else if (fault & VM_FAULT_MINOR)
 329                 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, addr);
 330
 331         /*
 332          * Handle the "normal" case first - VM_FAULT_MAJOR / VM_FAULT_MINOR
 333          */
 334         if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP | VM_FAULT_BADACCESS))))
 335                 return 0;
 336
 337         if (fault & VM_FAULT_OOM) {
 338                 /*
 339                  * We ran out of memory, call the OOM killer, and return to
 340                  * userspace (which will retry the fault, or kill us if we
 341                  * got oom-killed)
 342                  */
 343                 pagefault_out_of_memory();
 344                 return 0;
 345         }
 346
 347         /*
 348          * If we are in kernel mode at this point, we
 349          * have no context to handle this fault with.
 350          */
 351         if (!user_mode(regs))
 352                 goto no_context;
 353
 354         if (fault & VM_FAULT_SIGBUS) {
 355                 /*
 356                  * We had some memory, but were unable to
 357                  * successfully fix up this page fault.
 358                  */
 359                 sig = SIGBUS;
 360                 code = BUS_ADRERR;
 361         } else {
 362                 /*
 363                  * Something tried to access memory that
 364                  * isn't in our memory map..
 365                  */
 366                 sig = SIGSEGV;
 367                 code = fault == VM_FAULT_BADACCESS ?
 368                         SEGV_ACCERR : SEGV_MAPERR;
 369         }
 370
 371         __do_user_fault(tsk, addr, fsr, sig, code, regs);
 372         return 0;
 373
 374 no_context:
 375         __do_kernel_fault(mm, addr, fsr, regs);
 376         return 0;
 377 }
 378 #else                                   /* CONFIG_MMU */
 379 static int
 380 do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 381 {
 382         return 0;
 383 }
 384 #endif                                  /* CONFIG_MMU */
 385
 386 /*
 387  * First Level Translation Fault Handler
 388  *
 389  * We enter here because the first level page table doesn't contain
 390  * a valid entry for the address.
 391  *
 392  * If the address is in kernel space (>= TASK_SIZE), then we are
 393  * probably faulting in the vmalloc() area.
 394  *
 395  * If the init_task's first level page tables contains the relevant
 396  * entry, we copy the it to this task.  If not, we send the process
 397  * a signal, fixup the exception, or oops the kernel.
 398  *
 399  * NOTE! We MUST NOT take any locks for this case. We may be in an
 400  * interrupt or a critical region, and should only copy the information
 401  * from the master page table, nothing more.
 402  */
 403 #ifdef CONFIG_MMU
 404 static int __kprobes
 405 do_translation_fault(unsigned long addr, unsigned int fsr,
 406                      struct pt_regs *regs)
 407 {
 408         unsigned int index;
 409         pgd_t *pgd, *pgd_k;
 410         pud_t *pud, *pud_k;
 411         pmd_t *pmd, *pmd_k;
 412
 413         if (addr < TASK_SIZE)
 414                 return do_page_fault(addr, fsr, regs);
 415
 416         if (user_mode(regs))
 417                 goto bad_area;
 418
 419         index = pgd_index(addr);
 420
 421         /*
 422          * FIXME: CP15 C1 is write only on ARMv3 architectures.
 423          */
 424         pgd = cpu_get_pgd() + index;
 425         pgd_k = init_mm.pgd + index;
 426
 427         if (pgd_none(*pgd_k))
 428                 goto bad_area;
 429         if (!pgd_present(*pgd))
 430                 set_pgd(pgd, *pgd_k);
 431
 432         pud = pud_offset(pgd, addr);
 433         pud_k = pud_offset(pgd_k, addr);
 434
 435         if (pud_none(*pud_k))
 436                 goto bad_area;
 437         if (!pud_present(*pud))
 438                 set_pud(pud, *pud_k);
 439
 440         pmd = pmd_offset(pud, addr);
 441         pmd_k = pmd_offset(pud_k, addr);
 442
 443         /*
 444          * On ARM one Linux PGD entry contains two hardware entries (see page
 445          * tables layout in pgtable.h). We normally guarantee that we always
 446          * fill both L1 entries. But create_mapping() doesn't follow the rule.
 447          * It can create inidividual L1 entries, so here we have to call
 448          * pmd_none() check for the entry really corresponded to address, not
 449          * for the first of pair.
 450          */
 451         index = (addr >> SECTION_SHIFT) & 1;
 452         if (pmd_none(pmd_k[index]))
 453                 goto bad_area;
 454
 455         copy_pmd(pmd, pmd_k);
 456         return 0;
 457
 458 bad_area:
 459         do_bad_area(addr, fsr, regs);
 460         return 0;
 461 }
 462 #else                                   /* CONFIG_MMU */
 463 static int
 464 do_translation_fault(unsigned long addr, unsigned int fsr,
 465                      struct pt_regs *regs)
 466 {
 467         return 0;
 468 }
 469 #endif                                  /* CONFIG_MMU */
 470
 471 /*
 472  * Some section permission faults need to be handled gracefully.
 473  * They can happen due to a __{get,put}_user during an oops.
 474  */
 475 static int
 476 do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 477 {
 478         do_bad_area(addr, fsr, regs);
 479         return 0;
 480 }
 481
 482 /*
 483  * This abort handler always returns "fault".
 484  */
 485 static int
 486 do_bad(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 487 {
 488         return 1;
 489 }
 490
 491 static struct fsr_info {
 492         int     (*fn)(unsigned long addr, unsigned int fsr, struct pt_regs *regs);
 493         int     sig;
 494         int     code;
 495         const char *name;
 496 } fsr_info[] = {
 497         /*
 498          * The following are the standard ARMv3 and ARMv4 aborts.  ARMv5
 499          * defines these to be "precise" aborts.
 500          */
 501         { do_bad,               SIGSEGV, 0,             "vector exception"                 },
 502         { do_bad,               SIGBUS,  BUS_ADRALN,    "alignment exception"              },
 503         { do_bad,               SIGKILL, 0,             "terminal exception"               },
 504         { do_bad,               SIGBUS,  BUS_ADRALN,    "alignment exception"              },
 505         { do_bad,               SIGBUS,  0,             "external abort on linefetch"      },
 506         { do_translation_fault, SIGSEGV, SEGV_MAPERR,   "section translation fault"        },
 507         { do_bad,               SIGBUS,  0,             "external abort on linefetch"      },
 508         { do_page_fault,        SIGSEGV, SEGV_MAPERR,   "page translation fault"           },
 509         { do_bad,               SIGBUS,  0,             "external abort on non-linefetch"  },
 510         { do_bad,               SIGSEGV, SEGV_ACCERR,   "section domain fault"             },
 511         { do_bad,               SIGBUS,  0,             "external abort on non-linefetch"  },
 512         { do_bad,               SIGSEGV, SEGV_ACCERR,   "page domain fault"                },
 513         { do_bad,               SIGBUS,  0,             "external abort on translation"    },
 514         { do_sect_fault,        SIGSEGV, SEGV_ACCERR,   "section permission fault"         },
 515         { do_bad,               SIGBUS,  0,             "external abort on translation"    },
 516         { do_page_fault,        SIGSEGV, SEGV_ACCERR,   "page permission fault"            },
 517         /*
 518          * The following are "imprecise" aborts, which are signalled by bit
 519          * 10 of the FSR, and may not be recoverable.  These are only
 520          * supported if the CPU abort handler supports bit 10.
 521          */
 522         { do_bad,               SIGBUS,  0,             "unknown 16"                       },
 523         { do_bad,               SIGBUS,  0,             "unknown 17"                       },
 524         { do_bad,               SIGBUS,  0,             "unknown 18"                       },
 525         { do_bad,               SIGBUS,  0,             "unknown 19"                       },
 526         { do_bad,               SIGBUS,  0,             "lock abort"                       }, /* xscale */
 527         { do_bad,               SIGBUS,  0,             "unknown 21"                       },
 528         { do_bad,               SIGBUS,  BUS_OBJERR,    "imprecise external abort"         }, /* xscale */
 529         { do_bad,               SIGBUS,  0,             "unknown 23"                       },
 530         { do_bad,               SIGBUS,  0,             "dcache parity error"              }, /* xscale */
 531         { do_bad,               SIGBUS,  0,             "unknown 25"                       },
 532         { do_bad,               SIGBUS,  0,             "unknown 26"                       },
 533         { do_bad,               SIGBUS,  0,             "unknown 27"                       },
 534         { do_bad,               SIGBUS,  0,             "unknown 28"                       },
 535         { do_bad,               SIGBUS,  0,             "unknown 29"                       },
 536         { do_bad,               SIGBUS,  0,             "unknown 30"                       },
 537         { do_bad,               SIGBUS,  0,             "unknown 31"                       }
 538 };
 539
 540 void __init
 541 hook_fault_code(int nr, int (*fn)(unsigned long, unsigned int, struct pt_regs *),
 542                 int sig, int code, const char *name)
 543 {
 544         if (nr < 0 || nr >= ARRAY_SIZE(fsr_info))
 545                 BUG();
 546
 547         fsr_info[nr].fn   = fn;
 548         fsr_info[nr].sig  = sig;
 549         fsr_info[nr].code = code;
 550         fsr_info[nr].name = name;
 551 }
 552
 553 /*
 554  * Dispatch a data abort to the relevant handler.
 555  */
 556 asmlinkage void __exception
 557 do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 558 {
 559         const struct fsr_info *inf = fsr_info + fsr_fs(fsr);
 560         struct siginfo info;
 561
 562         if (!inf->fn(addr, fsr & ~FSR_LNX_PF, regs))
 563                 return;
 564
 565         printk(KERN_ALERT "Unhandled fault: %s (0x%03x) at 0x%08lx\n",
 566                 inf->name, fsr, addr);
 567
 568         info.si_signo = inf->sig;
 569         info.si_errno = 0;
 570         info.si_code  = inf->code;
 571         info.si_addr  = (void __user *)addr;
 572         arm_notify_die("", regs, &info, fsr, 0);
 573 }
 574
 575
 576 static struct fsr_info ifsr_info[] = {
 577         { do_bad,               SIGBUS,  0,             "unknown 0"                        },
 578         { do_bad,               SIGBUS,  0,             "unknown 1"                        },
 579         { do_bad,               SIGBUS,  0,             "debug event"                      },
 580         { do_bad,               SIGSEGV, SEGV_ACCERR,   "section access flag fault"        },
 581         { do_bad,               SIGBUS,  0,             "unknown 4"                        },
 582         { do_translation_fault, SIGSEGV, SEGV_MAPERR,   "section translation fault"        },
 583         { do_bad,               SIGSEGV, SEGV_ACCERR,   "page access flag fault"           },
 584         { do_page_fault,        SIGSEGV, SEGV_MAPERR,   "page translation fault"           },
 585         { do_bad,               SIGBUS,  0,             "external abort on non-linefetch"  },
 586         { do_bad,               SIGSEGV, SEGV_ACCERR,   "section domain fault"             },
 587         { do_bad,               SIGBUS,  0,             "unknown 10"                       },
 588         { do_bad,               SIGSEGV, SEGV_ACCERR,   "page domain fault"                },
 589         { do_bad,               SIGBUS,  0,             "external abort on translation"    },
 590         { do_sect_fault,        SIGSEGV, SEGV_ACCERR,   "section permission fault"         },
 591         { do_bad,               SIGBUS,  0,             "external abort on translation"    },
 592         { do_page_fault,        SIGSEGV, SEGV_ACCERR,   "page permission fault"            },
 593         { do_bad,               SIGBUS,  0,             "unknown 16"                       },
 594         { do_bad,               SIGBUS,  0,             "unknown 17"                       },
 595         { do_bad,               SIGBUS,  0,             "unknown 18"                       },
 596         { do_bad,               SIGBUS,  0,             "unknown 19"                       },
 597         { do_bad,               SIGBUS,  0,             "unknown 20"                       },
 598         { do_bad,               SIGBUS,  0,             "unknown 21"                       },
 599         { do_bad,               SIGBUS,  0,             "unknown 22"                       },
 600         { do_bad,               SIGBUS,  0,             "unknown 23"                       },
 601         { do_bad,               SIGBUS,  0,             "unknown 24"                       },
 602         { do_bad,               SIGBUS,  0,             "unknown 25"                       },
 603         { do_bad,               SIGBUS,  0,             "unknown 26"                       },
 604         { do_bad,               SIGBUS,  0,             "unknown 27"                       },
 605         { do_bad,               SIGBUS,  0,             "unknown 28"                       },
 606         { do_bad,               SIGBUS,  0,             "unknown 29"                       },
 607         { do_bad,               SIGBUS,  0,             "unknown 30"                       },
 608         { do_bad,               SIGBUS,  0,             "unknown 31"                       },
 609 };
 610
 611 void __init
 612 hook_ifault_code(int nr, int (*fn)(unsigned long, unsigned int, struct pt_regs *),
 613                  int sig, int code, const char *name)
 614 {
 615         if (nr < 0 || nr >= ARRAY_SIZE(ifsr_info))
 616                 BUG();
 617
 618         ifsr_info[nr].fn   = fn;
 619         ifsr_info[nr].sig  = sig;
 620         ifsr_info[nr].code = code;
 621         ifsr_info[nr].name = name;
 622 }
 623
 624 asmlinkage void __exception
 625 do_PrefetchAbort(unsigned long addr, unsigned int ifsr, struct pt_regs *regs)
 626 {
 627         const struct fsr_info *inf = ifsr_info + fsr_fs(ifsr);
 628         struct siginfo info;
 629
 630         if (!inf->fn(addr, ifsr | FSR_LNX_PF, regs))
 631                 return;
 632
 633         printk(KERN_ALERT "Unhandled prefetch abort: %s (0x%03x) at 0x%08lx\n",
 634                 inf->name, ifsr, addr);
 635
 636         info.si_signo = inf->sig;
 637         info.si_errno = 0;
 638         info.si_code  = inf->code;
 639         info.si_addr  = (void __user *)addr;
 640         arm_notify_die("", regs, &info, ifsr, 0);
 641 }
 642
 643 static int __init exceptions_init(void)
 644 {
 645         if (cpu_architecture() >= CPU_ARCH_ARMv6) {
 646                 hook_fault_code(4, do_translation_fault, SIGSEGV, SEGV_MAPERR,
 647                                 "I-cache maintenance fault");
 648         }
 649
 650         if (cpu_architecture() >= CPU_ARCH_ARMv7) {
 651                 /*
 652                  * TODO: Access flag faults introduced in ARMv6K.
 653                  * Runtime check for 'K' extension is needed
 654                  */
 655                 hook_fault_code(3, do_bad, SIGSEGV, SEGV_MAPERR,
 656                                 "section access flag fault");
 657                 hook_fault_code(6, do_bad, SIGSEGV, SEGV_MAPERR,
 658                                 "section access flag fault");
 659         }
 660
 661         return 0;
 662 }
 663
 664 arch_initcall(exceptions_init);