x86: configuration options to compile out x86 CPU support code

This patch adds some configuration options that allow to compile out
CPU vendor-specific code in x86 kernels (in arch/x86/kernel/cpu). The
new configuration options are only visible when CONFIG_EMBEDDED is
selected, as they are mostly interesting for space savings reasons.

An example of size saving, on x86 with only Intel CPU support:

   text	   data	    bss	    dec	    hex	filename
1125479	 118760	 212992	1457231	 163c4f	vmlinux.old
1121355	 116536	 212992	1450883	 162383	vmlinux
  -4124   -2224       0   -6348   -18CC +/-

However, I'm not exactly sure that the Kconfig wording is correct with
regard to !64BIT / 64BIT.

[ mingo@elte.hu: convert macro to inline ]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/Kconfig.cpu

@@ -415,3 +415,73 @@ config X86_MINIMUM_CPU_FAMILY
 config X86_DEBUGCTLMSR
 	def_bool y
 	depends on !(MK6 || MWINCHIPC6 || MWINCHIP2 || MWINCHIP3D || MCYRIXIII || M586MMX || M586TSC || M586 || M486 || M386)
+
+menuconfig PROCESSOR_SELECT
+	default y
+	bool "Supported processor vendors" if EMBEDDED
+	help
+	  This lets you choose what x86 vendor support code your kernel
+	  will include.
+
+config CPU_SUP_INTEL_32
+	default y
+	bool "Support Intel processors" if PROCESSOR_SELECT
+	depends on !64BIT
+	help
+	  This enables extended support for Intel processors
+
+config CPU_SUP_INTEL_64
+	default y
+	bool "Support Intel processors" if PROCESSOR_SELECT
+	depends on 64BIT
+	help
+	  This enables extended support for Intel processors
+
+config CPU_SUP_CYRIX_32
+	default y
+	bool "Support Cyrix processors" if PROCESSOR_SELECT
+	depends on !64BIT
+	help
+	  This enables extended support for Cyrix processors
+
+config CPU_SUP_AMD_32
+	default y
+	bool "Support AMD processors" if PROCESSOR_SELECT
+	depends on !64BIT
+	help
+	  This enables extended support for AMD processors
+
+config CPU_SUP_AMD_64
+	default y
+	bool "Support AMD processors" if PROCESSOR_SELECT
+	depends on 64BIT
+	help
+	  This enables extended support for AMD processors
+
+config CPU_SUP_CENTAUR_32
+	default y
+	bool "Support Centaur processors" if PROCESSOR_SELECT
+	depends on !64BIT
+	help
+	  This enables extended support for Centaur processors
+
+config CPU_SUP_CENTAUR_64
+	default y
+	bool "Support Centaur processors" if PROCESSOR_SELECT
+	depends on 64BIT
+	help
+	  This enables extended support for Centaur processors
+
+config CPU_SUP_TRANSMETA_32
+	default y
+	bool "Support Transmeta processors" if PROCESSOR_SELECT
+	depends on !64BIT
+	help
+	  This enables extended support for Transmeta processors
+
+config CPU_SUP_UMC_32
+	default y
+	bool "Support UMC processors" if PROCESSOR_SELECT
+	depends on !64BIT
+	help
+	  This enables extended support for UMC processors

arch/x86/kernel/cpu/Makefile

@@ -7,15 +7,16 @@ obj-y			+= proc.o feature_names.o
 
 obj-$(CONFIG_X86_32)	+= common.o bugs.o cmpxchg.o
 obj-$(CONFIG_X86_64)	+= common_64.o bugs_64.o
-obj-$(CONFIG_X86_32)	+= amd.o
-obj-$(CONFIG_X86_64)	+= amd_64.o
-obj-$(CONFIG_X86_32)	+= cyrix.o
-obj-$(CONFIG_X86_32)	+= centaur.o
-obj-$(CONFIG_X86_64)	+= centaur_64.o
-obj-$(CONFIG_X86_32)	+= transmeta.o
-obj-$(CONFIG_X86_32)	+= intel.o
-obj-$(CONFIG_X86_64)	+= intel_64.o
-obj-$(CONFIG_X86_32)	+= umc.o
+
+obj-$(CONFIG_CPU_SUP_AMD_32)		+= amd.o
+obj-$(CONFIG_CPU_SUP_AMD_64)		+= amd_64.o
+obj-$(CONFIG_CPU_SUP_CYRIX_32)		+= cyrix.o
+obj-$(CONFIG_CPU_SUP_CENTAUR_32)	+= centaur.o
+obj-$(CONFIG_CPU_SUP_CENTAUR_64)	+= centaur_64.o
+obj-$(CONFIG_CPU_SUP_TRANSMETA_32)	+= transmeta.o
+obj-$(CONFIG_CPU_SUP_INTEL_32)		+= intel.o
+obj-$(CONFIG_CPU_SUP_INTEL_64)		+= intel_64.o
+obj-$(CONFIG_CPU_SUP_UMC_32)		+= umc.o
 
 obj-$(CONFIG_X86_MCE)	+= mcheck/
 obj-$(CONFIG_MTRR)	+= mtrr/

include/asm-x86/bugs.h

@@ -2,6 +2,11 @@
 #define _ASM_X86_BUGS_H
 
 extern void check_bugs(void);
+
+#ifdef CONFIG_CPU_SUP_INTEL_32
 int ppro_with_ram_bug(void);
+#else
+static inline int ppro_with_ram_bug(void) { return 0; }
+#endif
 
 #endif /* _ASM_X86_BUGS_H */