* [PATCH v2] lib/extable.c: use bsearch() library function in search_extable()
@ 2017-06-03 22:38 Thomas Meyer
2017-06-11 22:18 ` LKML
0 siblings, 1 reply; 2+ messages in thread
From: Thomas Meyer @ 2017-06-03 22:38 UTC (permalink / raw)
To: Rasmus Villemoes, linux-kernel
Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
---
include/linux/extable.h | 3 ++-
kernel/extable.c | 2 +-
kernel/module.c | 2 +-
lib/extable.c | 38 +++++++++++++++++++-------------------
4 files changed, 23 insertions(+), 22 deletions(-)
diff --git a/include/linux/extable.h b/include/linux/extable.h
index 7effea4..b575bb9 100644
--- a/include/linux/extable.h
+++ b/include/linux/extable.h
@@ -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,
+ const size_t num,
unsigned long value);
void sort_extable(struct exception_table_entry *start,
struct exception_table_entry *finish);
diff --git a/kernel/extable.c b/kernel/extable.c
index 2676d7f..0c25b75 100644
--- a/kernel/extable.c
+++ b/kernel/extable.c
@@ -55,7 +55,7 @@ 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;
diff --git a/kernel/module.c b/kernel/module.c
index 4a3665f..22faf11 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -4201,7 +4201,7 @@ 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();
diff --git a/lib/extable.c b/lib/extable.c
index 62968da..d4d3929 100644
--- a/lib/extable.c
+++ b/lib/extable.c
@@ -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 k = *(unsigned long*) key;
+
+ /* avoid overflow */
+ if (k > ex_to_insn(_elt))
+ return 1;
+ if (k < 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,
@@ -102,24 +117,9 @@ void trim_init_extable(struct module *m)
*/
const struct exception_table_entry *
search_extable(const struct exception_table_entry *first,
- const struct exception_table_entry *last,
+ 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, first, num, sizeof(struct exception_table_entry), cmp_ex_search);
}
#endif
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] lib/extable.c: use bsearch() library function in search_extable()
2017-06-03 22:38 [PATCH v2] lib/extable.c: use bsearch() library function in search_extable() Thomas Meyer
@ 2017-06-11 22:18 ` LKML
0 siblings, 0 replies; 2+ messages in thread
From: LKML @ 2017-06-11 22:18 UTC (permalink / raw)
To: Thomas Meyer; +Cc: Rasmus Villemoes, linux-kernel
With kind regards
Thomas
> Am 04.06.2017 um 00:38 schrieb Thomas Meyer <thomas@m3y3r.de>:
>
> Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
> ---
> include/linux/extable.h | 3 ++-
> kernel/extable.c | 2 +-
> kernel/module.c | 2 +-
> lib/extable.c | 38 +++++++++++++++++++-------------------
> 4 files changed, 23 insertions(+), 22 deletions(-)
>
> diff --git a/include/linux/extable.h b/include/linux/extable.h
> index 7effea4..b575bb9 100644
> --- a/include/linux/extable.h
> +++ b/include/linux/extable.h
> @@ -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,
> + const size_t num,
> unsigned long value);
> void sort_extable(struct exception_table_entry *start,
> struct exception_table_entry *finish);
> diff --git a/kernel/extable.c b/kernel/extable.c
> index 2676d7f..0c25b75 100644
> --- a/kernel/extable.c
> +++ b/kernel/extable.c
> @@ -55,7 +55,7 @@ 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;
> diff --git a/kernel/module.c b/kernel/module.c
> index 4a3665f..22faf11 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -4201,7 +4201,7 @@ 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();
> diff --git a/lib/extable.c b/lib/extable.c
> index 62968da..d4d3929 100644
> --- a/lib/extable.c
> +++ b/lib/extable.c
> @@ -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 k = *(unsigned long*) key;
> +
> + /* avoid overflow */
> + if (k > ex_to_insn(_elt))
> + return 1;
> + if (k < 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,
> @@ -102,24 +117,9 @@ void trim_init_extable(struct module *m)
> */
> const struct exception_table_entry *
> search_extable(const struct exception_table_entry *first,
> - const struct exception_table_entry *last,
> + 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, first, num, sizeof(struct exception_table_entry), cmp_ex_search);
> }
> #endif
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2017-06-11 22:43 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-06-03 22:38 [PATCH v2] lib/extable.c: use bsearch() library function in search_extable() Thomas Meyer
2017-06-11 22:18 ` LKML
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).