x86/microcode: Hide the config knob

In reality CONFIG_MICROCODE is enabled in any reasonable configuration when
Intel or AMD support is enabled. Accommodate to reality.

Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230812195727.660453052@linutronix.de

Author: KAGA-KOKO

arch/x86/Kconfig

@@ -1308,44 +1308,8 @@ config X86_REBOOTFIXUPS
 	  Say N otherwise.
 
 config MICROCODE
-	bool "CPU microcode loading support"
-	default y
+	def_bool y
 	depends on CPU_SUP_AMD || CPU_SUP_INTEL
-	help
-	  If you say Y here, you will be able to update the microcode on
-	  Intel and AMD processors. The Intel support is for the IA32 family,
-	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
-	  AMD support is for families 0x10 and later. You will obviously need
-	  the actual microcode binary data itself which is not shipped with
-	  the Linux kernel.
-
-	  The preferred method to load microcode from a detached initrd is described
-	  in Documentation/arch/x86/microcode.rst. For that you need to enable
-	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
-	  initrd for microcode blobs.
-
-	  In addition, you can build the microcode into the kernel. For that you
-	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
-	  config option.
-
-config MICROCODE_INTEL
-	bool "Intel microcode loading support"
-	depends on CPU_SUP_INTEL && MICROCODE
-	default MICROCODE
-	help
-	  This options enables microcode patch loading support for Intel
-	  processors.
-
-	  For the current Intel microcode data package go to
-	  <https://downloadcenter.intel.com> and search for
-	  'Linux Processor Microcode Data File'.
-
-config MICROCODE_AMD
-	bool "AMD microcode loading support"
-	depends on CPU_SUP_AMD && MICROCODE
-	help
-	  If you select this option, microcode patch loading support for AMD
-	  processors will be enabled.
 
 config MICROCODE_LATE_LOADING
 	bool "Late microcode loading (DANGEROUS)"

arch/x86/include/asm/microcode.h

@@ -54,16 +54,16 @@ struct ucode_cpu_info {
 extern struct ucode_cpu_info ucode_cpu_info[];
 struct cpio_data find_microcode_in_initrd(const char *path, bool use_pa);
 
-#ifdef CONFIG_MICROCODE_INTEL
+#ifdef CONFIG_CPU_SUP_INTEL
 extern struct microcode_ops * __init init_intel_microcode(void);
 #else
 static inline struct microcode_ops * __init init_intel_microcode(void)
 {
 	return NULL;
 }
-#endif /* CONFIG_MICROCODE_INTEL */
+#endif /* CONFIG_CPU_SUP_INTEL */
 
-#ifdef CONFIG_MICROCODE_AMD
+#ifdef CONFIG_CPU_SUP_AMD
 extern struct microcode_ops * __init init_amd_microcode(void);
 extern void __exit exit_amd_microcode(void);
 #else

arch/x86/include/asm/microcode_amd.h

@@ -43,7 +43,7 @@ struct microcode_amd {
 
 #define PATCH_MAX_SIZE (3 * PAGE_SIZE)
 
-#ifdef CONFIG_MICROCODE_AMD
+#ifdef CONFIG_CPU_SUP_AMD
 extern void load_ucode_amd_early(unsigned int cpuid_1_eax);
 extern int __init save_microcode_in_initrd_amd(unsigned int family);
 void reload_ucode_amd(unsigned int cpu);

arch/x86/include/asm/microcode_intel.h

@@ -71,7 +71,7 @@ static inline u32 intel_get_microcode_revision(void)
 	return rev;
 }
 
-#ifdef CONFIG_MICROCODE_INTEL
+#ifdef CONFIG_CPU_SUP_INTEL
 extern void __init load_ucode_intel_bsp(void);
 extern void load_ucode_intel_ap(void);
 extern void show_ucode_info_early(void);

arch/x86/kernel/cpu/microcode/Makefile

@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
 microcode-y				:= core.o
 obj-$(CONFIG_MICROCODE)			+= microcode.o
-microcode-$(CONFIG_MICROCODE_INTEL)	+= intel.o
-microcode-$(CONFIG_MICROCODE_AMD)	+= amd.o
+microcode-$(CONFIG_CPU_SUP_INTEL)	+= intel.o
+microcode-$(CONFIG_CPU_SUP_AMD)		+= amd.o