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/*
* Kernel exception handling table support. Derived from arch/alpha/mm/extable.c.
*
* Copyright (C) 1998, 1999 Hewlett-Packard Co
* Copyright (C) 1998, 1999 David Mosberger-Tang <davidm@hpl.hp.com>
*/
#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 const struct exception_table_entry *
search_one_table (const struct exception_table_entry *first,
const struct exception_table_entry *last,
signed long value)
{
/* Abort early if the search value is out of range. */
if (value != (signed int)value)
return 0;
while (first <= last) {
const struct exception_table_entry *mid;
long diff;
/*
* We know that first and last are both kernel virtual
* pointers (region 7) so first+last will cause an
* overflow. We fix that by calling __va() on the
* result, which will ensure that the top two bits get
* set again.
*/
mid = (void *) __va((((__u64) first + (__u64) last)/2/sizeof(*mid))*sizeof(*mid));
diff = mid->addr - value;
if (diff == 0)
return mid;
else if (diff < 0)
first = mid+1;
else
last = mid-1;
}
return 0;
}
register unsigned long gp __asm__("gp");
const struct exception_table_entry *
search_exception_table (unsigned long addr)
{
#ifndef CONFIG_MODULE
/* There is only the kernel to search. */
return search_one_table(__start___ex_table, __stop___ex_table - 1, addr - gp);
#else
struct exception_table_entry *ret;
/* The kernel is the last "module" -- no need to treat it special. */
struct module *mp;
for (mp = module_list; mp ; mp = mp->next) {
if (!mp->ex_table_start)
continue;
ret = search_one_table(mp->ex_table_start, mp->ex_table_end - 1, addr - mp->gp);
if (ret)
return ret;
}
return 0;
#endif
}
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