linux-kernel - [PATCH] x86/microcode: Make update

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Message-Id: <20180524154420.24455-1-swood@redhat.com>
Date:   Thu, 24 May 2018 10:44:20 -0500
From:   Scott Wood <swood@...hat.com>
To:     Borislav Petkov <bp@...en8.de>
Cc:     linux-kernel@...r.kernel.org, Pei Zhang <pezhang@...hat.com>,
        Clark Williams <williams@...hat.com>, x86@...nel.org,
        Scott Wood <swood@...hat.com>
Subject: [PATCH] x86/microcode: Make update_lock raw

__reload_late() is called from stop_machine context and thus
cannot acquire a non-raw spinlock on PREEMPT_RT.

Signed-off-by: Scott Wood <swood@...hat.com>
---
 arch/x86/kernel/cpu/microcode/core.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 77e201301528..08286269fd24 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -70,7 +70,7 @@ static DEFINE_MUTEX(microcode_mutex);
 /*
  * Serialize late loading so that CPUs get updated one-by-one.
  */
-static DEFINE_SPINLOCK(update_lock);
+static DEFINE_RAW_SPINLOCK(update_lock);
 
 struct ucode_cpu_info		ucode_cpu_info[NR_CPUS];
 
@@ -560,9 +560,9 @@ static int __reload_late(void *info)
 	if (__wait_for_cpus(&late_cpus_in, NSEC_PER_SEC))
 		return -1;
 
-	spin_lock(&update_lock);
+	raw_spin_lock(&update_lock);
 	apply_microcode_local(&err);
-	spin_unlock(&update_lock);
+	raw_spin_unlock(&update_lock);
 
 	/* siblings return UCODE_OK because their engine got updated already */
 	if (err > UCODE_NFOUND) {
-- 
2.17.0