/* * 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[]; #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