linux-kernel - [PATCH 1/2] Fix Sandy Bridge microcode check to actually work

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Date:	Fri, 13 Jul 2012 17:58:13 -0700
From:	Andi Kleen <andi@...stfloor.org>
To:	mingo@...e.hu
Cc:	eranian@...gle.com, a.p.zijlstra@...llo.nl,
	linux-kernel@...r.kernel.org, Andi Kleen <ak@...ux.intel.com>
Subject: [PATCH 1/2] Fix Sandy Bridge microcode check to actually work

From: Andi Kleen <ak@...ux.intel.com>

- The old style microcode interface used by microcode_ctl didn't call
the perf callback.
- The pebs_broken bitfield needs to be unsigned, otherwise the one bit
signed bitfield gets sign extended and any microcode revision on a update
passes, and later updates are ignored.

Signed-off-by: Andi Kleen <ak@...ux.intel.com>
---
 arch/x86/kernel/cpu/perf_event.h |    2 +-
 arch/x86/kernel/microcode_core.c |    3 +++
 2 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
index a15df4b..1b12fac 100644
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -374,7 +374,7 @@ struct x86_pmu {
 	/*
 	 * Intel DebugStore bits
 	 */
-	int		bts		:1,
+	unsigned	bts		:1,
 			bts_active	:1,
 			pebs		:1,
 			pebs_active	:1,
diff --git a/arch/x86/kernel/microcode_core.c b/arch/x86/kernel/microcode_core.c
index 4873e62..d4f4d31 100644
--- a/arch/x86/kernel/microcode_core.c
+++ b/arch/x86/kernel/microcode_core.c
@@ -228,6 +228,9 @@ static ssize_t microcode_write(struct file *file, const char __user *buf,
 	mutex_unlock(&microcode_mutex);
 	put_online_cpus();
 
+	if (ret >= 0)
+		perf_check_microcode();
+
 	return ret;
 }
 
-- 
1.7.7.6

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