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/*

 *  linux/arch/arm/mm/fault.c

 *

 *  Copyright (C) 1995  Linus Torvalds

 *  Modifications for ARM processor (c) 1995, 1996 Russell King

 */

#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>

#define FAULT_CODE_READ         0x02

#define FAULT_CODE_USER         0x01

extern void die_if_kernel(char *msg, struct pt_regs *regs, unsigned int err, unsigned int ret);

static void kernel_page_fault (unsigned long addr, int mode, struct pt_regs *regs,

                               struct task_struct *tsk, struct mm_struct *mm)

{

        /*

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

         * terminate things with extreme prejudice.

         */

        if (addr < PAGE_SIZE)

            printk (KERN_ALERT "Unable to handle kernel NULL pointer dereference");

        else

            printk (KERN_ALERT "Unable to handle kernel paging request");

        printk (" at virtual address %08lx\n", addr);

        die_if_kernel ("Oops", regs, mode, SIGKILL);

        do_exit (SIGKILL);

}

static void page_fault (unsigned long addr, int mode, struct pt_regs *regs)

{

        struct task_struct *tsk = current;

        struct mm_struct *mm = tsk->mm;

        struct vm_area_struct *vma;

        if (mode & FAULT_CODE_USER) {

                tsk->tss.error_code = mode;

                tsk->tss.trap_no = 14;

                printk ("%s: memory violation at pc=0x%08lx, lr=0x%08lx (bad address=0x%08lx, code %d)\n",

                        tsk->comm, regs->ARM_pc, regs->ARM_lr, addr, mode);

#ifdef DEBUG

                show_regs (regs);

                c_backtrace (regs->ARM_fp, regs->ARM_cpsr);

#endif

                force_sig(SIGSEGV, tsk);

                return;

        }

        kernel_page_fault (addr, mode, regs, tsk, mm);

}

/*

 * Handle a data abort.  Note that we have to handle a range of addresses

 * on ARM2/3 for ldm.  If both pages are zero-mapped, then we have to force

 * a copy-on-write

 */

asmlinkage void

do_DataAbort (unsigned long addr, int fsr, int error_code, struct pt_regs *regs)

{

        if (user_mode(regs))

                error_code |= FAULT_CODE_USER;

#define DIE(signr,nam)\

                force_sig(signr, current);\

                die_if_kernel(nam, regs, fsr, signr);\

                break;

        switch (fsr & 15) {

        case 2:

                DIE(SIGKILL, "Terminal exception")

        case 0:

                DIE(SIGSEGV, "Vector exception")

        case 1:

        case 3:

                DIE(SIGBUS, "Alignment exception")

        case 12:

        case 14:

                DIE(SIGBUS, "External abort on translation")

        case 9:

        case 11:

                DIE(SIGSEGV, "Domain fault")

        case 13:/* permission fault on section */

#ifndef DEBUG

                show_regs(regs);

                {

                        unsigned int i, j, a;

                        a = regs->ARM_sp;

                        for (j = 0; j < 10; j++) {

                                printk ("%08x: ", a);

                                for (i = 0; i < 8; i += 1, a += 4)

                                        printk ("%08lx ", *(unsigned long *)a);

                                printk ("\n");

                        }

                }

#endif

                DIE(SIGSEGV, "Permission fault")

        case 15:/* permission fault on page */

        case 5: /* page-table entry descriptor fault */

        case 7: /* first-level descriptor fault */

                page_fault (addr, error_code, regs);

                break;

        case 4:

        case 6:

                DIE(SIGBUS, "External abort on linefetch")

        case 8:

        case 10:

                DIE(SIGBUS, "External abort on non-linefetch")

        }

}

asmlinkage int

do_PrefetchAbort (unsigned long addr, struct pt_regs *regs)

{

#if 0

        /* does this still apply ? */

        if (the memc mapping for this page exists - can check now...) {

                printk ("Page in, but got abort (undefined instruction?)\n");

                return 0;

        }

#endif

        page_fault (addr, FAULT_CODE_USER|FAULT_CODE_READ, regs);

        return 1;

}