blob: 3f677a8f0c3c101421a4003fd286260b771a6a6b [file] [log] [blame]
* lib/extable.c
* 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/config.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sort.h>
#include <asm/uaccess.h>
extern struct exception_table_entry __start___ex_table[];
extern struct exception_table_entry __stop___ex_table[];
* 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);
* 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;
return mid;
return NULL;