/*
 * arch/ubicom32/mm/fault.c
 *   Ubicom32 architecture page fault implementation.
 *
 * (C) Copyright 2009, Ubicom, Inc.
 *  Copyright (C) 1998  D. Jeff Dionne <jeff@lineo.ca>,
 *  Copyright (C) 2000  Lineo, Inc.  (www.lineo.com)
 *
 *  Based on:
 *
 *  linux/arch/m68k/mm/fault.c
 *
 *  Copyright (C) 1995  Hamish Macdonald
 *
 * This file is part of the Ubicom32 Linux Kernel Port.
 *
 * The Ubicom32 Linux Kernel Port is free software: you can redistribute
 * it and/or modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation, either version 2 of the
 * License, or (at your option) any later version.
 *
 * The Ubicom32 Linux Kernel Port is distributed in the hope that it
 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 * the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with the Ubicom32 Linux Kernel Port.  If not,
 * see <http://www.gnu.org/licenses/>.
 *
 * Ubicom32 implementation derived from (with many thanks):
 *   arch/m68knommu
 *   arch/blackfin
 *   arch/parisc
 */

#include <linux/module.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/ptrace.h>

#include <asm/system.h>
#include <asm/pgtable.h>

extern void die_if_kernel(char *, struct pt_regs *, long);

/*
 * This routine handles page faults.  It determines the problem, and
 * then passes it off to one of the appropriate routines.
 *
 * error_code:
 *	bit 0 == 0 means no page found, 1 means protection fault
 *	bit 1 == 0 means read, 1 means write
 *
 * If this routine detects a bad access, it returns 1, otherwise it
 * returns 0.
 */
asmlinkage int do_page_fault(struct pt_regs *regs, unsigned long address,
			      unsigned long error_code)
{
#ifdef DEBUG
	printk (KERN_DEBUG "regs->sr=%#x, regs->pc=%#lx, address=%#lx, %ld\n",
		regs->sr, regs->pc, address, error_code);
#endif

	/*
	 * Oops. The kernel tried to access some bad page. We'll have to
	 * terminate things with extreme prejudice.
	 */
	if ((unsigned long) address < PAGE_SIZE) {
		printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
	} else
		printk(KERN_ALERT "Unable to handle kernel access");
	printk(KERN_ALERT " at virtual address %08lx\n",address);
	die_if_kernel("Oops", regs, error_code);
	do_exit(SIGKILL);

	return 1;
}