linux-kernel - [tip:x86/urgent] x86/microcode: Make sure boot_cpu

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Message-ID: <tip-370a132bb2227ff76278f98370e0e701d86ff752@git.kernel.org>
Date:   Sun, 2 Sep 2018 05:15:50 -0700
From:   tip-bot for Prarit Bhargava <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     tglx@...utronix.de, bp@...e.de, tony.luck@...el.com,
        linux-kernel@...r.kernel.org, hpa@...or.com, prarit@...hat.com,
        mingo@...nel.org
Subject: [tip:x86/urgent] x86/microcode: Make sure boot_cpu_data.microcode
 is up-to-date

Commit-ID:  370a132bb2227ff76278f98370e0e701d86ff752
Gitweb:     https://git.kernel.org/tip/370a132bb2227ff76278f98370e0e701d86ff752
Author:     Prarit Bhargava <prarit@...hat.com>
AuthorDate: Tue, 31 Jul 2018 07:27:39 -0400
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Sun, 2 Sep 2018 14:10:54 +0200

x86/microcode: Make sure boot_cpu_data.microcode is up-to-date

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@...hat.com>
Signed-off-by: Borislav Petkov <bp@...e.de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Tony Luck <tony.luck@...el.com>
Cc: sironi@...zon.de
Cc: stable@...r.kernel.org
Link: http://lkml.kernel.org/r/20180731112739.32338-1-prarit@redhat.com
---
 arch/x86/kernel/cpu/microcode/amd.c   | 4 ++++
 arch/x86/kernel/cpu/microcode/intel.c | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index 0624957aa068..602f17134103 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -537,6 +537,10 @@ static enum ucode_state 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 UCODE_UPDATED;
 }
 
diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index 97ccf4c3b45b..256d336cbc04 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -851,6 +851,10 @@ static enum ucode_state 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 UCODE_UPDATED;
 }