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Message-Id: <46D4107C.76E4.0078.0@novell.com>
Date: Tue, 28 Aug 2007 11:09:32 +0100
From: "Jan Beulich" <jbeulich@...ell.com>
To: <linux-kernel@...r.kernel.org>
Subject: [PATCH] constify string/array kparam tracking structures
.. in an effort to make read-only whatever can be made, so that
CONFIG_DEBUG_RODATA can catch as many issues as possible.
Signed-off-by: Jan Beulich <jbeulich@...ell.com>
include/linux/moduleparam.h | 18 +++++++++++-------
kernel/params.c | 17 +++++++----------
2 files changed, 18 insertions(+), 17 deletions(-)
--- linux-2.6.23-rc4/include/linux/moduleparam.h 2007-04-26 05:08:32.000000000 +0200
+++ 2.6.23-rc4-const-kparam/include/linux/moduleparam.h 2007-08-20 09:50:12.000000000 +0200
@@ -38,7 +38,11 @@ struct kernel_param {
unsigned int perm;
param_set_fn set;
param_get_fn get;
- void *arg;
+ union {
+ void *arg;
+ const struct kparam_string *str;
+ const struct kparam_array *arr;
+ };
};
/* Special one for strings we want to copy into */
@@ -66,11 +70,11 @@ struct kparam_array
/* Default value instead of permissions? */ \
static int __param_perm_check_##name __attribute__((unused)) = \
BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2)); \
- static char __param_str_##name[] = prefix #name; \
+ static const char __param_str_##name[] = prefix #name; \
static struct kernel_param const __param_##name \
__attribute_used__ \
__attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
- = { __param_str_##name, perm, set, get, arg }
+ = { __param_str_##name, perm, set, get, { arg } }
#define module_param_call(name, set, get, arg, perm) \
__module_param_call(MODULE_PARAM_PREFIX, name, set, get, arg, perm)
@@ -88,10 +92,10 @@ struct kparam_array
/* Actually copy string: maxlen param is usually sizeof(string). */
#define module_param_string(name, string, len, perm) \
- static struct kparam_string __param_string_##name \
+ static const struct kparam_string __param_string_##name \
= { len, string }; \
module_param_call(name, param_set_copystring, param_get_string, \
- &__param_string_##name, perm); \
+ .str = &__param_string_##name, perm); \
__MODULE_PARM_TYPE(name, "string")
/* Called on module insert or kernel boot */
@@ -149,11 +153,11 @@ extern int param_get_invbool(char *buffe
/* Comma-separated array: *nump is set to number they actually specified. */
#define module_param_array_named(name, array, type, nump, perm) \
- static struct kparam_array __param_arr_##name \
+ static const struct kparam_array __param_arr_##name \
= { ARRAY_SIZE(array), nump, param_set_##type, param_get_##type,\
sizeof(array[0]), array }; \
module_param_call(name, param_array_set, param_array_get, \
- &__param_arr_##name, perm); \
+ .arr = &__param_arr_##name, perm); \
__MODULE_PARM_TYPE(name, "array of " #type)
#define module_param_array(name, type, nump, perm) \
--- linux-2.6.23-rc4/kernel/params.c 2007-08-28 09:42:37.000000000 +0200
+++ 2.6.23-rc4-const-kparam/kernel/params.c 2007-08-20 10:07:33.000000000 +0200
@@ -252,8 +252,9 @@ int param_get_bool(char *buffer, struct
int param_set_invbool(const char *val, struct kernel_param *kp)
{
int boolval, ret;
- struct kernel_param dummy = { .arg = &boolval };
+ struct kernel_param dummy;
+ dummy.arg = &boolval;
ret = param_set_bool(val, &dummy);
if (ret == 0)
*(int *)kp->arg = !boolval;
@@ -262,11 +263,7 @@ int param_set_invbool(const char *val, s
int param_get_invbool(char *buffer, struct kernel_param *kp)
{
- int val;
- struct kernel_param dummy = { .arg = &val };
-
- val = !*(int *)kp->arg;
- return param_get_bool(buffer, &dummy);
+ return sprintf(buffer, "%c", (*(int *)kp->arg) ? 'N' : 'Y');
}
/* We break the rule and mangle the string. */
@@ -325,7 +322,7 @@ static int param_array(const char *name,
int param_array_set(const char *val, struct kernel_param *kp)
{
- struct kparam_array *arr = kp->arg;
+ const struct kparam_array *arr = kp->arr;
unsigned int temp_num;
return param_array(kp->name, val, 1, arr->max, arr->elem,
@@ -335,7 +332,7 @@ int param_array_set(const char *val, str
int param_array_get(char *buffer, struct kernel_param *kp)
{
int i, off, ret;
- struct kparam_array *arr = kp->arg;
+ const struct kparam_array *arr = kp->arr;
struct kernel_param p;
p = *kp;
@@ -354,7 +351,7 @@ int param_array_get(char *buffer, struct
int param_set_copystring(const char *val, struct kernel_param *kp)
{
- struct kparam_string *kps = kp->arg;
+ const struct kparam_string *kps = kp->str;
if (!val) {
printk(KERN_ERR "%s: missing param set value\n", kp->name);
@@ -371,7 +368,7 @@ int param_set_copystring(const char *val
int param_get_string(char *buffer, struct kernel_param *kp)
{
- struct kparam_string *kps = kp->arg;
+ const struct kparam_string *kps = kp->str;
return strlcpy(buffer, kps->string, kps->maxlen);
}
-
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