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Date: Wed, 16 Oct 2013 12:45:57 +0100
From: "Jan Beulich" <JBeulich@...e.com>
To: <mingo@...e.hu>, <tglx@...utronix.de>, <hpa@...or.com>
Cc: <linux-kernel@...r.kernel.org>
Subject: [PATCH, resend] x86-64: don't track CPU model data that is
used by 32-bit code only
struct cpu_dev's c_models is only ever set inside CONFIG_X86_32
conditionals (or code that's being built for 32-bit only), so there's
no use of reserving the (empty) space for the model names in a 64-bit
kernel.
Similarly, c_size_cache is only used in the #else of a CONFIG_X86_64
conditional, so reserving space for (and in one case even initializing)
that field is pointless for 64-bit kernels too.
While moving both fields to the end of the structure, I also noticed
that
- the c_models array size was one too small, potentially causing
table_lookup_model() to return garbage on Intel CPUs (intel.c's
instance was lacking the sentinel with family being zero), so the
patch bumps that by one,
- c_models' vendor sub-field was unused (and anyway redundant with
the base structure's c_x86_vendor field), so the patch deletes it.
Signed-off-by: Jan Beulich <jbeulich@...e.com>
---
arch/x86/kernel/cpu/amd.c | 2 +-
arch/x86/kernel/cpu/centaur.c | 6 ++++--
arch/x86/kernel/cpu/common.c | 4 +++-
arch/x86/kernel/cpu/cpu.h | 16 +++++++---------
arch/x86/kernel/cpu/intel.c | 8 ++++----
arch/x86/kernel/cpu/umc.c | 2 +-
6 files changed, 20 insertions(+), 18 deletions(-)
--- 3.12-rc5/arch/x86/kernel/cpu/amd.c
+++ 3.12-rc5-x86-cpu-32bit-only-pieces/arch/x86/kernel/cpu/amd.c
@@ -824,7 +824,7 @@ static const struct cpu_dev amd_cpu_dev
.c_ident = { "AuthenticAMD" },
#ifdef CONFIG_X86_32
.c_models = {
- { .vendor = X86_VENDOR_AMD, .family = 4, .model_names =
+ { .family = 4, .model_names =
{
[3] = "486 DX/2",
[7] = "486 DX/2-WB",
--- 3.12-rc5/arch/x86/kernel/cpu/centaur.c
+++ 3.12-rc5-x86-cpu-32bit-only-pieces/arch/x86/kernel/cpu/centaur.c
@@ -468,10 +468,10 @@ static void init_centaur(struct cpuinfo_
#endif
}
+#ifdef CONFIG_X86_32
static unsigned int
centaur_size_cache(struct cpuinfo_x86 *c, unsigned int size)
{
-#ifdef CONFIG_X86_32
/* VIA C3 CPUs (670-68F) need further shifting. */
if ((c->x86 == 6) && ((c->x86_model == 7) || (c->x86_model == 8)))
size >>= 8;
@@ -484,16 +484,18 @@ centaur_size_cache(struct cpuinfo_x86 *c
if ((c->x86 == 6) && (c->x86_model == 9) &&
(c->x86_mask == 1) && (size == 65))
size -= 1;
-#endif
return size;
}
+#endif
static const struct cpu_dev centaur_cpu_dev = {
.c_vendor = "Centaur",
.c_ident = { "CentaurHauls" },
.c_early_init = early_init_centaur,
.c_init = init_centaur,
+#ifdef CONFIG_X86_32
.c_size_cache = centaur_size_cache,
+#endif
.c_x86_vendor = X86_VENDOR_CENTAUR,
};
--- 3.12-rc5/arch/x86/kernel/cpu/common.c
+++ 3.12-rc5-x86-cpu-32bit-only-pieces/arch/x86/kernel/cpu/common.c
@@ -346,6 +346,7 @@ static void filter_cpuid_features(struct
/* Look up CPU names by table lookup. */
static const char *table_lookup_model(struct cpuinfo_x86 *c)
{
+#ifdef CONFIG_X86_32
const struct cpu_model_info *info;
if (c->x86_model >= 16)
@@ -356,11 +357,12 @@ static const char *table_lookup_model(st
info = this_cpu->c_models;
- while (info && info->family) {
+ while (info->family) {
if (info->family == c->x86)
return info->model_names[c->x86_model];
info++;
}
+#endif
return NULL; /* Not found */
}
--- 3.12-rc5/arch/x86/kernel/cpu/cpu.h
+++ 3.12-rc5-x86-cpu-32bit-only-pieces/arch/x86/kernel/cpu/cpu.h
@@ -1,12 +1,6 @@
#ifndef ARCH_X86_CPU_H
#define ARCH_X86_CPU_H
-struct cpu_model_info {
- int vendor;
- int family;
- const char *model_names[16];
-};
-
/* attempt to consolidate cpu attributes */
struct cpu_dev {
const char *c_vendor;
@@ -14,15 +8,19 @@ struct cpu_dev {
/* some have two possibilities for cpuid string */
const char *c_ident[2];
- struct cpu_model_info c_models[4];
-
void (*c_early_init)(struct cpuinfo_x86 *);
void (*c_bsp_init)(struct cpuinfo_x86 *);
void (*c_init)(struct cpuinfo_x86 *);
void (*c_identify)(struct cpuinfo_x86 *);
void (*c_detect_tlb)(struct cpuinfo_x86 *);
- unsigned int (*c_size_cache)(struct cpuinfo_x86 *, unsigned int);
int c_x86_vendor;
+#ifdef CONFIG_X86_32
+ unsigned int (*c_size_cache)(struct cpuinfo_x86 *, unsigned int);
+ struct cpu_model_info {
+ int family;
+ const char *model_names[16];
+ } c_models[5];
+#endif
};
struct _tlb_table {
--- 3.12-rc5/arch/x86/kernel/cpu/intel.c
+++ 3.12-rc5-x86-cpu-32bit-only-pieces/arch/x86/kernel/cpu/intel.c
@@ -666,7 +666,7 @@ static const struct cpu_dev intel_cpu_de
.c_ident = { "GenuineIntel" },
#ifdef CONFIG_X86_32
.c_models = {
- { .vendor = X86_VENDOR_INTEL, .family = 4, .model_names =
+ { .family = 4, .model_names =
{
[0] = "486 DX-25/33",
[1] = "486 DX-50",
@@ -679,7 +679,7 @@ static const struct cpu_dev intel_cpu_de
[9] = "486 DX/4-WB"
}
},
- { .vendor = X86_VENDOR_INTEL, .family = 5, .model_names =
+ { .family = 5, .model_names =
{
[0] = "Pentium 60/66 A-step",
[1] = "Pentium 60/66",
@@ -690,7 +690,7 @@ static const struct cpu_dev intel_cpu_de
[8] = "Mobile Pentium MMX"
}
},
- { .vendor = X86_VENDOR_INTEL, .family = 6, .model_names =
+ { .family = 6, .model_names =
{
[0] = "Pentium Pro A-step",
[1] = "Pentium Pro",
@@ -704,7 +704,7 @@ static const struct cpu_dev intel_cpu_de
[11] = "Pentium III (Tualatin)",
}
},
- { .vendor = X86_VENDOR_INTEL, .family = 15, .model_names =
+ { .family = 15, .model_names =
{
[0] = "Pentium 4 (Unknown)",
[1] = "Pentium 4 (Willamette)",
--- 3.12-rc5/arch/x86/kernel/cpu/umc.c
+++ 3.12-rc5-x86-cpu-32bit-only-pieces/arch/x86/kernel/cpu/umc.c
@@ -12,7 +12,7 @@ static const struct cpu_dev umc_cpu_dev
.c_vendor = "UMC",
.c_ident = { "UMC UMC UMC" },
.c_models = {
- { .vendor = X86_VENDOR_UMC, .family = 4, .model_names =
+ { .family = 4, .model_names =
{
[1] = "U5D",
[2] = "U5S",
--
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