extable.c

Linux内核源代码 为压缩文件 是<<Linux内核>>一书中的源代码

/*
 * linux/arch/mips/mm/extable.c
 */
#include <linux/config.h>
#include <linux/module.h>
#include <asm/uaccess.h>

extern const struct exception_table_entry __start___ex_table[];
extern const struct exception_table_entry __stop___ex_table[];

static inline unsigned long
search_one_table(const struct exception_table_entry *first,
                 const struct exception_table_entry *last,
                 unsigned long value)
{
	while (first <= last) {
		const struct exception_table_entry *mid;
		long diff;

		mid = (last - first) / 2 + first;
		diff = mid->insn - value;
		if (diff == 0)
			return mid->nextinsn;
		else if (diff < 0)
			first = mid+1;
		else
			last = mid-1;
	}
	return 0;
}

unsigned long
search_exception_table(unsigned long addr)
{
	unsigned long ret;

#ifndef CONFIG_MODULES
	/* There is only the kernel to search.  */
	ret = search_one_table(__start___ex_table, __stop___ex_table-1, addr);
	if (ret) return ret;
#else
	/* The kernel is the last "module" -- no need to treat it special.  */
	struct module *mp;
	for (mp = module_list; mp != NULL; mp = mp->next) {
		if (mp->ex_table_start == NULL)
			continue;
		ret = search_one_table(mp->ex_table_start,
				       mp->ex_table_end - 1, addr);
		if (ret) return ret;
	}
#endif

	return 0;
}