From: Prarit Bhargava <prarit@xxxxxxxxxx> commit 370a132bb2227ff76278f98370e0e701d86ff752 upstream. When preparing an MCE record for logging, boot_cpu_data.microcode is used to read out the microcode revision on the box. However, on systems where late microcode update has happened, the microcode revision output in a MCE log record is wrong because boot_cpu_data.microcode is not updated when the microcode gets updated. But, the microcode revision saved in boot_cpu_data's microcode member should be kept up-to-date, regardless, for consistency. Make it so. Fixes: fa94d0c6e0f3 ("x86/MCE: Save microcode revision in machine check records") Signed-off-by: Prarit Bhargava <prarit@xxxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Tony Luck <tony.luck@xxxxxxxxx> Cc: sironi@xxxxxxxxx Link: http://lkml.kernel.org/r/20180731112739.32338-1-prarit@xxxxxxxxxx [bwh: Backported to 4.4: adjust context] Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/kernel/cpu/microcode/amd.c | 4 ++++ arch/x86/kernel/cpu/microcode/intel.c | 4 ++++ 2 files changed, 8 insertions(+) --- a/arch/x86/kernel/cpu/microcode/amd.c +++ b/arch/x86/kernel/cpu/microcode/amd.c @@ -712,6 +712,10 @@ int apply_microcode_amd(int cpu) uci->cpu_sig.rev = mc_amd->hdr.patch_id; c->microcode = mc_amd->hdr.patch_id; + /* Update boot_cpu_data's revision too, if we're on the BSP: */ + if (c->cpu_index == boot_cpu_data.cpu_index) + boot_cpu_data.microcode = mc_amd->hdr.patch_id; + return 0; } --- a/arch/x86/kernel/cpu/microcode/intel.c +++ b/arch/x86/kernel/cpu/microcode/intel.c @@ -905,6 +905,10 @@ static int apply_microcode_intel(int cpu uci->cpu_sig.rev = rev; c->microcode = rev; + /* Update boot_cpu_data's revision too, if we're on the BSP: */ + if (c->cpu_index == boot_cpu_data.cpu_index) + boot_cpu_data.microcode = rev; + return 0; }