mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-25 13:14:07 +08:00
a94c33dd1f
[thomas@m3y3r.de: v3: fix arch specific implementations] Link: http://lkml.kernel.org/r/1497890858.12931.7.camel@m3y3r.de Signed-off-by: Thomas Meyer <thomas@m3y3r.de> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
127 lines
3.2 KiB
C
127 lines
3.2 KiB
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/bsearch.h>
|
|
#include <linux/module.h>
|
|
#include <linux/init.h>
|
|
#include <linux/sort.h>
|
|
#include <linux/uaccess.h>
|
|
|
|
#ifndef ARCH_HAS_RELATIVE_EXTABLE
|
|
#define ex_to_insn(x) ((x)->insn)
|
|
#else
|
|
static inline unsigned long ex_to_insn(const struct exception_table_entry *x)
|
|
{
|
|
return (unsigned long)&x->insn + x->insn;
|
|
}
|
|
#endif
|
|
|
|
#ifndef ARCH_HAS_SORT_EXTABLE
|
|
#ifndef ARCH_HAS_RELATIVE_EXTABLE
|
|
#define swap_ex NULL
|
|
#else
|
|
static void swap_ex(void *a, void *b, int size)
|
|
{
|
|
struct exception_table_entry *x = a, *y = b, tmp;
|
|
int delta = b - a;
|
|
|
|
tmp = *x;
|
|
x->insn = y->insn + delta;
|
|
y->insn = tmp.insn - delta;
|
|
|
|
#ifdef swap_ex_entry_fixup
|
|
swap_ex_entry_fixup(x, y, tmp, delta);
|
|
#else
|
|
x->fixup = y->fixup + delta;
|
|
y->fixup = tmp.fixup - delta;
|
|
#endif
|
|
}
|
|
#endif /* ARCH_HAS_RELATIVE_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_sort(const void *a, const void *b)
|
|
{
|
|
const struct exception_table_entry *x = a, *y = b;
|
|
|
|
/* avoid overflow */
|
|
if (ex_to_insn(x) > ex_to_insn(y))
|
|
return 1;
|
|
if (ex_to_insn(x) < ex_to_insn(y))
|
|
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_sort, swap_ex);
|
|
}
|
|
|
|
#ifdef CONFIG_MODULES
|
|
/*
|
|
* If the exception table is sorted, any referring to the module init
|
|
* will be at the beginning or the end.
|
|
*/
|
|
void trim_init_extable(struct module *m)
|
|
{
|
|
/*trim the beginning*/
|
|
while (m->num_exentries &&
|
|
within_module_init(ex_to_insn(&m->extable[0]), m)) {
|
|
m->extable++;
|
|
m->num_exentries--;
|
|
}
|
|
/*trim the end*/
|
|
while (m->num_exentries &&
|
|
within_module_init(ex_to_insn(&m->extable[m->num_exentries - 1]),
|
|
m))
|
|
m->num_exentries--;
|
|
}
|
|
#endif /* CONFIG_MODULES */
|
|
#endif /* !ARCH_HAS_SORT_EXTABLE */
|
|
|
|
#ifndef ARCH_HAS_SEARCH_EXTABLE
|
|
|
|
static int cmp_ex_search(const void *key, const void *elt)
|
|
{
|
|
const struct exception_table_entry *_elt = elt;
|
|
unsigned long _key = *(unsigned long *)key;
|
|
|
|
/* avoid overflow */
|
|
if (_key > ex_to_insn(_elt))
|
|
return 1;
|
|
if (_key < ex_to_insn(_elt))
|
|
return -1;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* 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 *base,
|
|
const size_t num,
|
|
unsigned long value)
|
|
{
|
|
return bsearch(&value, base, num,
|
|
sizeof(struct exception_table_entry), cmp_ex_search);
|
|
}
|
|
#endif
|