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x86, mtrr: Constify struct mtrr_ops

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This is part of the ops structure constification
effort started by Arjan van de Ven et al.

Benefits of this constification:

 * prevents modification of data that is shared
   (referenced) by many other structure instances
   at runtime

 * detects/prevents accidental (but not intentional)
   modification attempts on archs that enforce
   read-only kernel data at runtime

 * potentially better optimized code as the compiler
   can assume that the const data cannot be changed

 * the compiler/linker move const data into .rodata
   and therefore exclude them from false sharing

Signed-off-by: Emese Revfy <re.emese@gmail.com>
LKML-Reference: <4B65D712.3080804@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
Emese Revfy 2010-01-31 20:16:34 +01:00 committed by H. Peter Anvin
parent ab658321f3
commit 3b9cfc0a99
6 changed files with 10 additions and 10 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
arch/x86/kernel/cpu/mtrr/amd.c
View file

@ -108,7 +108,7 @@ amd_validate_add_page(unsigned long base, unsigned long size, unsigned int type)
return 0;
}
static struct mtrr_ops amd_mtrr_ops = {
static const struct mtrr_ops amd_mtrr_ops = {
.vendor = X86_VENDOR_AMD,
.set = amd_set_mtrr,
.get = amd_get_mtrr,

2
arch/x86/kernel/cpu/mtrr/centaur.c
View file

@ -110,7 +110,7 @@ centaur_validate_add_page(unsigned long base, unsigned long size, unsigned int t
return 0;
}
static struct mtrr_ops centaur_mtrr_ops = {
static const struct mtrr_ops centaur_mtrr_ops = {
.vendor = X86_VENDOR_CENTAUR,
.set = centaur_set_mcr,
.get = centaur_get_mcr,

2
arch/x86/kernel/cpu/mtrr/cyrix.c
View file

@ -265,7 +265,7 @@ static void cyrix_set_all(void)
post_set();
}
static struct mtrr_ops cyrix_mtrr_ops = {
static const struct mtrr_ops cyrix_mtrr_ops = {
.vendor = X86_VENDOR_CYRIX,
.set_all = cyrix_set_all,
.set = cyrix_set_arr,

2
arch/x86/kernel/cpu/mtrr/generic.c
View file

@ -752,7 +752,7 @@ int positive_have_wrcomb(void)
/*
* Generic structure...
*/
struct mtrr_ops generic_mtrr_ops = {
const struct mtrr_ops generic_mtrr_ops = {
.use_intel_if = 1,
.set_all = generic_set_all,
.get = generic_get_mtrr,

6
arch/x86/kernel/cpu/mtrr/main.c
View file

@ -60,14 +60,14 @@ static DEFINE_MUTEX(mtrr_mutex);
u64 size_or_mask, size_and_mask;
static bool mtrr_aps_delayed_init;
static struct mtrr_ops *mtrr_ops[X86_VENDOR_NUM];
static const struct mtrr_ops *mtrr_ops[X86_VENDOR_NUM];
struct mtrr_ops *mtrr_if;
const struct mtrr_ops *mtrr_if;
static void set_mtrr(unsigned int reg, unsigned long base,
unsigned long size, mtrr_type type);
void set_mtrr_ops(struct mtrr_ops *ops)
void set_mtrr_ops(const struct mtrr_ops *ops)
{
if (ops->vendor && ops->vendor < X86_VENDOR_NUM)
mtrr_ops[ops->vendor] = ops;

6
arch/x86/kernel/cpu/mtrr/mtrr.h
View file

@ -32,7 +32,7 @@ extern int generic_get_free_region(unsigned long base, unsigned long size,
extern int generic_validate_add_page(unsigned long base, unsigned long size,
unsigned int type);
extern struct mtrr_ops generic_mtrr_ops;
extern const struct mtrr_ops generic_mtrr_ops;
extern int positive_have_wrcomb(void);
@ -53,10 +53,10 @@ void fill_mtrr_var_range(unsigned int index,
u32 base_lo, u32 base_hi, u32 mask_lo, u32 mask_hi);
void get_mtrr_state(void);
extern void set_mtrr_ops(struct mtrr_ops *ops);
extern void set_mtrr_ops(const struct mtrr_ops *ops);
extern u64 size_or_mask, size_and_mask;
extern struct mtrr_ops *mtrr_if;
extern const struct mtrr_ops *mtrr_if;
#define is_cpu(vnd) (mtrr_if && mtrr_if->vendor == X86_VENDOR_##vnd)
#define use_intel() (mtrr_if && mtrr_if->use_intel_if == 1)