From 4167709bbf826512a52ebd6aafda2be104adaec9 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Mon, 9 Jan 2017 12:41:45 +0100 Subject: x86/microcode/intel: Add a helper which gives the microcode revision Since on Intel we're required to do CPUID(1) first, before reading the microcode revision MSR, let's add a special helper which does the required steps so that we don't forget to do them next time, when we want to read the microcode revision. Signed-off-by: Borislav Petkov Link: http://lkml.kernel.org/r/20170109114147.5082-4-bp@alien8.de Signed-off-by: Thomas Gleixner --- arch/x86/include/asm/microcode_intel.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/microcode_intel.h b/arch/x86/include/asm/microcode_intel.h index 195becc6f780..e793fc9a9b20 100644 --- a/arch/x86/include/asm/microcode_intel.h +++ b/arch/x86/include/asm/microcode_intel.h @@ -52,6 +52,21 @@ struct extended_sigtable { #define exttable_size(et) ((et)->count * EXT_SIGNATURE_SIZE + EXT_HEADER_SIZE) +static inline u32 intel_get_microcode_revision(void) +{ + u32 rev, dummy; + + native_wrmsrl(MSR_IA32_UCODE_REV, 0); + + /* As documented in the SDM: Do a CPUID 1 here */ + native_cpuid_eax(1); + + /* get the current revision from MSR 0x8B */ + native_rdmsr(MSR_IA32_UCODE_REV, dummy, rev); + + return rev; +} + #ifdef CONFIG_MICROCODE_INTEL extern void __init load_ucode_intel_bsp(void); extern void load_ucode_intel_ap(void); -- cgit