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/*

 * Derived from arch/ppc/mm/extable.c and arch/i386/mm/extable.c.

 *

 * Copyright (C) 2004 Paul Mackerras, IBM Corp.

 *

 * This program 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.

 */

#include <linux/module.h>

#include <linux/init.h>

#include <linux/sort.h>

#include <asm/uaccess.h>

#ifndef ARCH_HAS_SORT_EXTABLE

/*

 * The exception table needs to be sorted so that the binary

 * search that we use to find entries in it works properly.

 * This is used both for the kernel exception table and for

 * the exception tables of modules that get loaded.

 */

static int cmp_ex(const void *a, const void *b)

{

        const struct exception_table_entry *x = a, *y = b;

        /* avoid overflow */

        if (x->insn > y->insn)

                return 1;

        if (x->insn < y->insn)

                return -1;

        return 0;

}

void sort_extable(struct exception_table_entry *start,

                  struct exception_table_entry *finish)

{

        sort(start, finish - start, sizeof(struct exception_table_entry),

             cmp_ex, NULL);

}

#endif

#ifndef ARCH_HAS_SEARCH_EXTABLE

/*

 * Search one exception table for an entry corresponding to the

 * given instruction address, and return the address of the entry,

 * or NULL if none is found.

 * We use a binary search, and thus we assume that the table is

 * already sorted.

 */

const struct exception_table_entry *

search_extable(const struct exception_table_entry *first,

               const struct exception_table_entry *last,

               unsigned long value)

{

        while (first <= last) {

                const struct exception_table_entry *mid;

                mid = (last - first) / 2 + first;

                /*

                 * careful, the distance between entries can be

                 * larger than 2GB:

                 */

                if (mid->insn < value)

                        first = mid + 1;

                else if (mid->insn > value)

                        last = mid - 1;

                else

                        return mid;

        }

        return NULL;

}

#endif