arch: x86: Introduce new config for CPU legacy model namestiny/no-legacy-cpu-model-names

Add a new config X86_MODEL_TABLE to compile out the legacy model tables
for 32bit systems in order to save space. The new config depends on
X86_32 and PROC_FS.

Model names tables for CPUs that do not have the brand-string CPUIDs
(0x80000002-0x80000004) are kept in field legacy_model in struct
cpu_dev. Previously, this field was wrapped inside ifdef CONFIG_X86_32.
This patch moves this field inside ifdef CONFIG_X86_MODEL_TABLE so that
it can be compiled out on x86-32 systems too.

bloat-o-meter output:
add/remove: 0/0 grow/shrink: 0/9 up/down: 0/-2780 (-2780)
function                                     old     new   delta
identify_cpu                                 777     717     -60
umc_cpu_dev                                  380      40    -340
transmeta_cpu_dev                            380      40    -340
nsc_cpu_dev                                  380      40    -340
intel_cpu_dev                                380      40    -340
default_cpu                                  380      40    -340
cyrix_cpu_dev                                380      40    -340
centaur_cpu_dev                              380      40    -340
amd_cpu_dev                                  380      40    -340

Signed-off-by: Catalina Mocanu <catalina.mocanu@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Josh Triplett <josh@joshtriplett.org>

6 files changed, 21 insertions, 4 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index f2327e88e07cc6..72ed8c2dc3fcb6 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -314,6 +314,16 @@ config SMP
 
 	  If you don't know what to do here, say N.
 
+config X86_MODEL_TABLE
+	bool "Enable X86 CPU model names table for 32bit systems"
+	depends on X86_32 && PROC_FS
+	default y
+	help
+	  This option provides tables of model names for CPUs that do
+	  not have the brand-string CPUIDs (0x80000002 through 0x80000004).
+
+	  If you want to save space on a 32bit system, set this option to n.
+
 config X86_FEATURE_NAMES
 	bool "Processor feature human-readable names" if EMBEDDED
 	default y
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 813d29d00a175c..1e8f9ab21d2bdb 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -783,7 +783,7 @@ static void cpu_detect_tlb_amd(struct cpuinfo_x86 *c)
 static const struct cpu_dev amd_cpu_dev = {
 	.c_vendor	= "AMD",
 	.c_ident	= { "AuthenticAMD" },
-#ifdef CONFIG_X86_32
+#ifdef CONFIG_X86_MODEL_TABLE
 	.legacy_models = {
 		{ .family = 4, .model_names =
 		  {
@@ -796,6 +796,8 @@ static const struct cpu_dev amd_cpu_dev = {
 		  }
 		},
 	},
+#endif
+#ifdef CONFIG_X86_32
 	.legacy_cache_size = amd_size_cache,
 #endif
 	.c_early_init   = early_init_amd,
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 4b4f78c9ba1902..b770c5428560cb 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -361,7 +361,7 @@ static void filter_cpuid_features(struct cpuinfo_x86 *c, bool warn)
 /* Look up CPU names by table lookup. */
 static const char *table_lookup_model(struct cpuinfo_x86 *c)
 {
-#ifdef CONFIG_X86_32
+#ifdef CONFIG_X86_MODEL_TABLE
 	const struct legacy_cpu_model_info *info;
 
 	if (c->x86_model >= 16)
diff --git a/arch/x86/kernel/cpu/cpu.h b/arch/x86/kernel/cpu/cpu.h
index c37dc37e8317f1..ff2a55ea132d8c 100644
--- a/arch/x86/kernel/cpu/cpu.h
+++ b/arch/x86/kernel/cpu/cpu.h
@@ -18,7 +18,8 @@ struct cpu_dev {
 	/* Optional vendor specific routine to obtain the cache size. */
 	unsigned int	(*legacy_cache_size)(struct cpuinfo_x86 *,
 					     unsigned int);
-
+#endif
+#ifdef CONFIG_X86_MODEL_TABLE
 	/* Family/stepping-based lookup table for model names. */
 	struct legacy_cpu_model_info {
 		int		family;
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 1ef456273172c8..06d90efd75f3ea 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -692,7 +692,7 @@ static void intel_detect_tlb(struct cpuinfo_x86 *c)
 static const struct cpu_dev intel_cpu_dev = {
 	.c_vendor	= "Intel",
 	.c_ident	= { "GenuineIntel" },
-#ifdef CONFIG_X86_32
+#ifdef CONFIG_X86_MODEL_TABLE
 	.legacy_models = {
 		{ .family = 4, .model_names =
 		  {
@@ -743,6 +743,8 @@ static const struct cpu_dev intel_cpu_dev = {
 		  }
 		},
 	},
+#endif
+#ifdef CONFIG_X86_32
 	.legacy_cache_size = intel_size_cache,
 #endif
 	.c_detect_tlb	= intel_detect_tlb,
diff --git a/arch/x86/kernel/cpu/umc.c b/arch/x86/kernel/cpu/umc.c
index ef9c2a0078bd66..b9ecbbfa51222a 100644
--- a/arch/x86/kernel/cpu/umc.c
+++ b/arch/x86/kernel/cpu/umc.c
@@ -10,6 +10,7 @@
 static const struct cpu_dev umc_cpu_dev = {
 	.c_vendor	= "UMC",
 	.c_ident	= { "UMC UMC UMC" },
+#ifdef CONFIG_X86_MODEL_TABLE
 	.legacy_models	= {
 		{ .family = 4, .model_names =
 		  {
@@ -18,6 +19,7 @@ static const struct cpu_dev umc_cpu_dev = {
 		  }
 		},
 	},
+#endif
 	.c_x86_vendor	= X86_VENDOR_UMC,
 };