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lib/extable.c: use bsearch() library function in search_extable()

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[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>
This commit is contained in:
Thomas Meyer 2017-07-10 15:51:58 -07:00 committed by Linus Torvalds
parent 12e8fd6fd3
commit a94c33dd1f
8 changed files with 63 additions and 56 deletions
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3
arch/mips/kernel/module.c
View File

@ -317,7 +317,8 @@ const struct exception_table_entry *search_module_dbetables(unsigned long addr)
spin_lock_irqsave(&dbe_lock, flags);
list_for_each_entry(dbe, &dbe_list, dbe_list) {
e = search_extable(dbe->dbe_start, dbe->dbe_end - 1, addr);
e = search_extable(dbe->dbe_start,
dbe->dbe_end - dbe->dbe_start, addr);
if (e)
break;
}

3
arch/mips/kernel/traps.c
View File

@ -429,7 +429,8 @@ static const struct exception_table_entry *search_dbe_tables(unsigned long addr)
{
const struct exception_table_entry *e;
e = search_extable(__start___dbe_table, __stop___dbe_table - 1, addr);
e = search_extable(__start___dbe_table,
__stop___dbe_table - __start___dbe_table, addr);
if (!e)
e = search_module_dbetables(addr);
return e;

34
arch/sh/mm/extable_64.c
View File

@ -10,6 +10,7 @@
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/bsearch.h>
#include <linux/rwsem.h>
#include <linux/extable.h>
#include <linux/uaccess.h>
@ -40,10 +41,23 @@ static const struct exception_table_entry *check_exception_ranges(unsigned long
return NULL;
}
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 > _elt->insn)
return 1;
if (_key < _elt->insn)
return -1;
return 0;
}
/* Simple binary search */
const struct exception_table_entry *
search_extable(const struct exception_table_entry *first,
const struct exception_table_entry *last,
search_extable(const struct exception_table_entry *base,
const size_t num,
unsigned long value)
{
const struct exception_table_entry *mid;
@ -52,20 +66,8 @@ search_extable(const struct exception_table_entry *first,
if (mid)
return mid;
while (first <= last) {
long diff;
mid = (last - first) / 2 + first;
diff = mid->insn - value;
if (diff == 0)
return mid;
else if (diff < 0)
first = mid+1;
else
last = mid-1;
}
return NULL;
return bsearch(&value, base, num,
sizeof(struct exception_table_entry), cmp_ex_search);
}
int fixup_exception(struct pt_regs *regs)

28
arch/sparc/mm/extable.c
View File

@ -13,11 +13,11 @@ void sort_extable(struct exception_table_entry *start,
/* Caller knows they are in a range if ret->fixup == 0 */
const struct exception_table_entry *
search_extable(const struct exception_table_entry *start,
const struct exception_table_entry *last,
search_extable(const struct exception_table_entry *base,
const size_t num,
unsigned long value)
{
const struct exception_table_entry *walk;
int i;
/* Single insn entries are encoded as:
* word 1: insn address
@ -37,30 +37,30 @@ search_extable(const struct exception_table_entry *start,
*/
/* 1. Try to find an exact match. */
for (walk = start; walk <= last; walk++) {
if (walk->fixup == 0) {
for (i = 0; i < num; i++) {
if (base[i].fixup == 0) {
/* A range entry, skip both parts. */
walk++;
i++;
continue;
}
/* A deleted entry; see trim_init_extable */
if (walk->fixup == -1)
if (base[i].fixup == -1)
continue;
if (walk->insn == value)
return walk;
if (base[i].insn == value)
return &base[i];
}
/* 2. Try to find a range match. */
for (walk = start; walk <= (last - 1); walk++) {
if (walk->fixup)
for (i = 0; i < (num - 1); i++) {
if (base[i].fixup)
continue;
if (walk[0].insn <= value && walk[1].insn > value)
return walk;
if (base[i].insn <= value && base[i + 1].insn > value)
return &base[i];
walk++;
i++;
}
return NULL;

5
include/linux/extable.h
View File

@ -2,13 +2,14 @@
#define _LINUX_EXTABLE_H
#include <linux/stddef.h> /* for NULL */
#include <linux/types.h>
struct module;
struct exception_table_entry;
const struct exception_table_entry *
search_extable(const struct exception_table_entry *first,
const struct exception_table_entry *last,
search_extable(const struct exception_table_entry *base,
const size_t num,
unsigned long value);
void sort_extable(struct exception_table_entry *start,
struct exception_table_entry *finish);

3
kernel/extable.c
View File

@ -55,7 +55,8 @@ const struct exception_table_entry *search_exception_tables(unsigned long addr)
{
const struct exception_table_entry *e;
e = search_extable(__start___ex_table, __stop___ex_table-1, addr);
e = search_extable(__start___ex_table,
__stop___ex_table - __start___ex_table, addr);
if (!e)
e = search_module_extables(addr);
return e;

2
kernel/module.c
View File

@ -4196,7 +4196,7 @@ const struct exception_table_entry *search_module_extables(unsigned long addr)
goto out;
e = search_extable(mod->extable,
mod->extable + mod->num_exentries - 1,
mod->num_exentries,
addr);
out:
preempt_enable();

41
lib/extable.c
View File

@ -9,6 +9,7 @@
* 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>
@ -51,7 +52,7 @@ static void swap_ex(void *a, void *b, int size)
* 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)
static int cmp_ex_sort(const void *a, const void *b)
{
const struct exception_table_entry *x = a, *y = b;
@ -67,7 +68,7 @@ void sort_extable(struct exception_table_entry *start,
struct exception_table_entry *finish)
{
sort(start, finish - start, sizeof(struct exception_table_entry),
cmp_ex, swap_ex);
cmp_ex_sort, swap_ex);
}
#ifdef CONFIG_MODULES
@ -93,6 +94,20 @@ void trim_init_extable(struct module *m)
#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,
@ -101,25 +116,11 @@ void trim_init_extable(struct module *m)
* already sorted.
*/
const struct exception_table_entry *
search_extable(const struct exception_table_entry *first,
const struct exception_table_entry *last,
search_extable(const struct exception_table_entry *base,
const size_t num,
unsigned long value)
{
while (first <= last) {
const struct exception_table_entry *mid;
mid = ((last - first) >> 1) + first;
/*
* careful, the distance between value and insn
* can be larger than MAX_LONG:
*/
if (ex_to_insn(mid) < value)
first = mid + 1;
else if (ex_to_insn(mid) > value)
last = mid - 1;
else
return mid;
}
return NULL;
return bsearch(&value, base, num,
sizeof(struct exception_table_entry), cmp_ex_search);
}
#endif