Subversion Repositories or1k

/*

 *  arch/mips/mm/fault.c

 *

 *  Copyright (C) 1995 by Ralf Baechle

 */

#include <linux/signal.h>

#include <linux/sched.h>

#include <linux/head.h>

#include <linux/kernel.h>

#include <linux/errno.h>

#include <linux/string.h>

#include <linux/types.h>

#include <linux/ptrace.h>

#include <linux/mman.h>

#include <linux/mm.h>

#include <asm/system.h>

#include <asm/segment.h>

#include <asm/pgtable.h>

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

/*

 * This routine handles page faults.  It determines the address,

 * and the problem, and then passes it off to one of the appropriate

 * routines.

 */

asmlinkage void

do_page_fault(struct pt_regs *regs, unsigned long writeaccess, unsigned long address)

{

        struct vm_area_struct * vma;

#if 0

        printk("do_page_fault() #1: %s %08lx (epc == %08lx, ra == %08lx)\n",

               writeaccess ? "writeaccess to" : "readaccess from",

               address, regs->cp0_epc, regs->reg31);

#endif

        vma = find_vma(current, address);

        if (!vma)

                goto bad_area;

        if (vma->vm_start <= address)

                goto good_area;

        if (!(vma->vm_flags & VM_GROWSDOWN))

                goto bad_area;

        if (expand_stack(vma, address))

                goto bad_area;

/*

 * Ok, we have a good vm_area for this memory access, so

 * we can handle it..

 */

good_area:

        if (writeaccess) {

                if (!(vma->vm_flags & VM_WRITE))

                        goto bad_area;

        } else {

                if (!(vma->vm_flags & (VM_READ | VM_EXEC)))

                        goto bad_area;

        }

        handle_mm_fault(vma, address, writeaccess);

        /* FIXME: This flushes the cache far to often */

        sys_cacheflush(address, PAGE_SIZE, BCACHE);

        return;

/*

 * Something tried to access memory that isn't in our memory map..

 * Fix it, but check if it's kernel or user first..

 */

bad_area:

        if (user_mode(regs)) {

                current->tss.cp0_badvaddr = address;

                current->tss.error_code = writeaccess;

                send_sig(SIGSEGV, current, 1);

                return;

        }

        /*

         * Oops. The kernel tried to access some bad page. We'll have to

         * terminate things with extreme prejudice.

         */

        printk(KERN_ALERT "Unable to handle kernel paging request at virtual "

               "address %08lx\n", address);

        die_if_kernel("Oops", regs, writeaccess);

        do_exit(SIGKILL);

}