x86/microcode: Untangle from BLK_DEV_INITRD
Thomas Voegtle reported that doing oldconfig with a .config which has
CONFIG_MICROCODE enabled but BLK_DEV_INITRD disabled prevents the
microcode loading mechanism from being built.
So untangle it from the BLK_DEV_INITRD dependency so that oldconfig
doesn't turn it off and add an explanatory text to its Kconfig help what
the supported methods for supplying microcode are.
Reported-by: Thomas Voegtle <tv@lio96.de>
Tested-by: Thomas Voegtle <tv@lio96.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org> # 4.4
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1454499225-21544-2-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 9af2e63..405b185 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1159,22 +1159,23 @@
bool "CPU microcode loading support"
default y
depends on CPU_SUP_AMD || CPU_SUP_INTEL
- depends on BLK_DEV_INITRD
select FW_LOADER
---help---
-
If you say Y here, you will be able to update the microcode on
- certain 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.
+ 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.
- This option selects the general module only, you need to select
- at least one vendor specific module as well.
+ The preferred method to load microcode from a detached initrd is described
+ in Documentation/x86/early-microcode.txt. 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.
- To compile this driver as a module, choose M here: the module
- will be called microcode.
+ In addition, you can build-in the microcode into the kernel. For that you
+ need to enable FIRMWARE_IN_KERNEL and add the vendor-supplied microcode
+ to the CONFIG_EXTRA_FIRMWARE config option.
config MICROCODE_INTEL
bool "Intel microcode loading support"