x86/microcode: Do not select FW_LOADER (c8a59a4d) · Commits · 戴 / test

The x86 microcode support works just fine without FW_LOADER. In fact, these days most people load microcode early during boot so FW_LOADER never gets into the picture anyway. As almost everyone on x86 needs to enable MICROCODE, this by extension means that FW_LOADER is always built into the kernel even if nothing uses it. The FW_LOADER system is about two thousand lines long and contains user-space facing interfaces that could potentially provide an entry point into the kernel (or beyond). Remove the unnecessary select of FW_LOADER by MICROCODE. People who need the FW_LOADER capability can still enable it. [ bp: Massage a bit. ] Signed-off-by:

Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by:

Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200610042911.GA20058@gondor.apana.org.au

arch/x86/Kconfig

+0 −3

Original line number	Diff line number	Diff line
		@@ -1292,7 +1292,6 @@ config MICROCODE
		bool "CPU microcode loading support"
		default y
		depends on CPU_SUP_AMD \|\| CPU_SUP_INTEL
		select FW_LOADER
		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,
		@@ -1314,7 +1313,6 @@ config MICROCODE_INTEL
		bool "Intel microcode loading support"
		depends on MICROCODE
		default MICROCODE
		select FW_LOADER
		help
		This options enables microcode patch loading support for Intel
		processors.
		@@ -1326,7 +1324,6 @@ config MICROCODE_INTEL
		config MICROCODE_AMD
		bool "AMD microcode loading support"
		depends on MICROCODE
		select FW_LOADER
		help
		If you select this option, microcode patch loading support for AMD
		processors will be enabled.

arch/x86/kernel/cpu/microcode/core.c

+0 −2

Original line number	Diff line number	Diff line
		@@ -145,7 +145,6 @@ extern struct builtin_fw __end_builtin_fw[];

		bool get_builtin_firmware(struct cpio_data cd, const char name)
		{
		#ifdef CONFIG_FW_LOADER
		struct builtin_fw *b_fw;

		for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
		@@ -155,7 +154,6 @@ bool get_builtin_firmware(struct cpio_data cd, const char name)
		return true;
		}
		}
		#endif
		return false;
		}

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