target/linux/ubicom32/files/arch/ubicom32/mm/fault.c

   1 /*
   2  * arch/ubicom32/mm/fault.c
   3  *   Ubicom32 architecture page fault implementation.
   4  *
   5  * (C) Copyright 2009, Ubicom, Inc.
   6  *  Copyright (C) 1998  D. Jeff Dionne <jeff@lineo.ca>,
   7  *  Copyright (C) 2000  Lineo, Inc.  (www.lineo.com)
   8  *
   9  *  Based on:
  10  *
  11  *  linux/arch/m68k/mm/fault.c
  12  *
  13  *  Copyright (C) 1995  Hamish Macdonald
  14  *
  15  * This file is part of the Ubicom32 Linux Kernel Port.
  16  *
  17  * The Ubicom32 Linux Kernel Port is free software: you can redistribute
  18  * it and/or modify it under the terms of the GNU General Public License
  19  * as published by the Free Software Foundation, either version 2 of the
  20  * License, or (at your option) any later version.
  21  *
  22  * The Ubicom32 Linux Kernel Port is distributed in the hope that it
  23  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  24  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  25  * the GNU General Public License for more details.
  26  *
  27  * You should have received a copy of the GNU General Public License
  28  * along with the Ubicom32 Linux Kernel Port.  If not,
  29  * see <http://www.gnu.org/licenses/>.
  30  *
  31  * Ubicom32 implementation derived from (with many thanks):
  32  *   arch/m68knommu
  33  *   arch/blackfin
  34  *   arch/parisc
  35  */
  36
  37 #include <linux/module.h>
  38 #include <linux/mman.h>
  39 #include <linux/mm.h>
  40 #include <linux/kernel.h>
  41 #include <linux/ptrace.h>
  42
  43 #include <asm/system.h>
  44 #include <asm/pgtable.h>
  45
  46 extern void die_if_kernel(char *, struct pt_regs *, long);
  47
  48 /*
  49  * This routine handles page faults.  It determines the problem, and
  50  * then passes it off to one of the appropriate routines.
  51  *
  52  * error_code:
  53  *      bit 0 == 0 means no page found, 1 means protection fault
  54  *      bit 1 == 0 means read, 1 means write
  55  *
  56  * If this routine detects a bad access, it returns 1, otherwise it
  57  * returns 0.
  58  */
  59 asmlinkage int do_page_fault(struct pt_regs *regs, unsigned long address,
  60                               unsigned long error_code)
  61 {
  62 #ifdef DEBUG
  63         printk (KERN_DEBUG "regs->sr=%#x, regs->pc=%#lx, address=%#lx, %ld\n",
  64                 regs->sr, regs->pc, address, error_code);
  65 #endif
  66
  67         /*
  68          * Oops. The kernel tried to access some bad page. We'll have to
  69          * terminate things with extreme prejudice.
  70          */
  71         if ((unsigned long) address < PAGE_SIZE) {
  72                 printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
  73         } else
  74                 printk(KERN_ALERT "Unable to handle kernel access");
  75         printk(KERN_ALERT " at virtual address %08lx\n",address);
  76         die_if_kernel("Oops", regs, error_code);
  77         do_exit(SIGKILL);
  78
  79         return 1;
  80 }