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