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Date: Wed, 2 Nov 2022 08:47:00 +0100
From: Juergen Gross <jgross@...e.com>
To: linux-kernel@...r.kernel.org, x86@...nel.org
Cc: Juergen Gross <jgross@...e.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
Dave Hansen <dave.hansen@...ux.intel.com>,
"H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH v5 03/16] x86/mtrr: replace use_intel() with a local flag
In MTRR code use_intel() is only used in one source file, and the
relevant use_intel_if member of struct mtrr_ops is set only in
generic_mtrr_ops.
Replace use_intel() with a single flag in cacheinfo.c, which can be set
when assigning generic_mtrr_ops to mtrr_if. This allows to drop
use_intel_if from mtrr_ops, while preparing to support PAT without
MTRR. As another preparation for the PAT/MTRR decoupling use a bit for
MTRR control and one for PAT control. For now set both bits together,
this can be changed later.
As the new flag will be set only if mtrr_enabled is set, the test for
mtrr_enabled can be dropped at some places.
Signed-off-by: Juergen Gross <jgross@...e.com>
---
V2:
- new patch
V4:
- rename cache_generic to memory_caching_control (Borislav Petkov)
- rename CACHE_GENERIC_* to CACHE_* (Borislav Petkov)
- get rid of use_generic in mtrr_bp_init() (Borislav Petkov)
V5:
- keep mtrr_enabled() (Borislav Petkov)
---
arch/x86/include/asm/cacheinfo.h | 5 +++++
arch/x86/kernel/cpu/cacheinfo.c | 3 +++
arch/x86/kernel/cpu/mtrr/generic.c | 1 -
arch/x86/kernel/cpu/mtrr/mtrr.c | 28 +++++++++++++---------------
arch/x86/kernel/cpu/mtrr/mtrr.h | 2 --
5 files changed, 21 insertions(+), 18 deletions(-)
diff --git a/arch/x86/include/asm/cacheinfo.h b/arch/x86/include/asm/cacheinfo.h
index 86b2e0dcc4bf..c3873962a7cd 100644
--- a/arch/x86/include/asm/cacheinfo.h
+++ b/arch/x86/include/asm/cacheinfo.h
@@ -2,6 +2,11 @@
#ifndef _ASM_X86_CACHEINFO_H
#define _ASM_X86_CACHEINFO_H
+/* Kernel controls MTRR and/or PAT MSRs. */
+extern unsigned int memory_caching_control;
+#define CACHE_MTRR 0x01
+#define CACHE_PAT 0x02
+
void cacheinfo_amd_init_llc_id(struct cpuinfo_x86 *c, int cpu);
void cacheinfo_hygon_init_llc_id(struct cpuinfo_x86 *c, int cpu);
diff --git a/arch/x86/kernel/cpu/cacheinfo.c b/arch/x86/kernel/cpu/cacheinfo.c
index 66556833d7af..5228fb9a3798 100644
--- a/arch/x86/kernel/cpu/cacheinfo.c
+++ b/arch/x86/kernel/cpu/cacheinfo.c
@@ -35,6 +35,9 @@ DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_llc_shared_map);
/* Shared L2 cache maps */
DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_l2c_shared_map);
+/* Kernel controls MTRR and/or PAT MSRs. */
+unsigned int memory_caching_control __ro_after_init;
+
struct _cache_table {
unsigned char descriptor;
char cache_type;
diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index cd64eab02393..81742870ecc5 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -917,7 +917,6 @@ int positive_have_wrcomb(void)
* Generic structure...
*/
const struct mtrr_ops generic_mtrr_ops = {
- .use_intel_if = 1,
.set_all = generic_set_all,
.get = generic_get_mtrr,
.get_free_region = generic_get_free_region,
diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.c b/arch/x86/kernel/cpu/mtrr/mtrr.c
index 2746cac9d8a9..4209945c4e68 100644
--- a/arch/x86/kernel/cpu/mtrr/mtrr.c
+++ b/arch/x86/kernel/cpu/mtrr/mtrr.c
@@ -46,6 +46,7 @@
#include <linux/syscore_ops.h>
#include <linux/rcupdate.h>
+#include <asm/cacheinfo.h>
#include <asm/cpufeature.h>
#include <asm/e820/api.h>
#include <asm/mtrr.h>
@@ -119,11 +120,11 @@ static int have_wrcomb(void)
}
/* This function returns the number of variable MTRRs */
-static void __init set_num_var_ranges(void)
+static void __init set_num_var_ranges(bool use_generic)
{
unsigned long config = 0, dummy;
- if (use_intel())
+ if (use_generic)
rdmsr(MSR_MTRRcap, config, dummy);
else if (is_cpu(AMD) || is_cpu(HYGON))
config = 2;
@@ -756,14 +757,16 @@ void __init mtrr_bp_init(void)
if (mtrr_if) {
__mtrr_enabled = true;
- set_num_var_ranges();
+ set_num_var_ranges(mtrr_if == &generic_mtrr_ops);
init_table();
- if (use_intel()) {
+ if (mtrr_if == &generic_mtrr_ops) {
/* BIOS may override */
__mtrr_enabled = get_mtrr_state();
- if (mtrr_enabled())
+ if (mtrr_enabled()) {
mtrr_bp_pat_init();
+ memory_caching_control |= CACHE_MTRR | CACHE_PAT;
+ }
if (mtrr_cleanup(phys_addr)) {
changed_by_mtrr_cleanup = 1;
@@ -786,10 +789,7 @@ void __init mtrr_bp_init(void)
void mtrr_ap_init(void)
{
- if (!mtrr_enabled())
- return;
-
- if (!use_intel() || mtrr_aps_delayed_init)
+ if (!memory_caching_control || mtrr_aps_delayed_init)
return;
/*
@@ -825,9 +825,7 @@ void mtrr_save_state(void)
void set_mtrr_aps_delayed_init(void)
{
- if (!mtrr_enabled())
- return;
- if (!use_intel())
+ if (!memory_caching_control)
return;
mtrr_aps_delayed_init = true;
@@ -838,7 +836,7 @@ void set_mtrr_aps_delayed_init(void)
*/
void mtrr_aps_init(void)
{
- if (!use_intel() || !mtrr_enabled())
+ if (!memory_caching_control)
return;
/*
@@ -855,7 +853,7 @@ void mtrr_aps_init(void)
void mtrr_bp_restore(void)
{
- if (!use_intel() || !mtrr_enabled())
+ if (!memory_caching_control)
return;
mtrr_if->set_all();
@@ -866,7 +864,7 @@ static int __init mtrr_init_finialize(void)
if (!mtrr_enabled())
return 0;
- if (use_intel()) {
+ if (memory_caching_control & CACHE_MTRR) {
if (!changed_by_mtrr_cleanup)
mtrr_state_warn();
return 0;
diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.h b/arch/x86/kernel/cpu/mtrr/mtrr.h
index 2ac99e561181..88b1c4b6174a 100644
--- a/arch/x86/kernel/cpu/mtrr/mtrr.h
+++ b/arch/x86/kernel/cpu/mtrr/mtrr.h
@@ -14,7 +14,6 @@ extern unsigned int mtrr_usage_table[MTRR_MAX_VAR_RANGES];
struct mtrr_ops {
u32 vendor;
- u32 use_intel_if;
void (*set)(unsigned int reg, unsigned long base,
unsigned long size, mtrr_type type);
void (*set_all)(void);
@@ -61,7 +60,6 @@ extern u64 size_or_mask, size_and_mask;
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)
extern unsigned int num_var_ranges;
extern u64 mtrr_tom2;
--
2.35.3
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