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/*
* 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 <asm/uaccess.h>
extern struct exception_table_entry __start___ex_table[];
extern struct exception_table_entry __stop___ex_table[];
#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.
*/
void sort_extable(struct exception_table_entry *start,
struct exception_table_entry *finish)
{
struct exception_table_entry el, *p, *q;
/* insertion sort */
for (p = start + 1; p < finish; ++p) {
/* start .. p-1 is sorted */
if (p[0].insn < p[-1].insn) {
/* move element p down to its right place */
el = *p;
q = p;
do {
/* el comes before q[-1], move q[-1] up one */
q[0] = q[-1];
--q;
} while (q > start && el.insn < q[-1].insn);
*q = el;
}
}
}
#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
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