This is a note to let you know that I've just added the patch titled
ARM: 8937/1: spectre-v2: remove Brahma-B53 from hardening
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm-8937-1-spectre-v2-remove-brahma-b53-from-hardeni.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 1cc29e5eeeea7778d8987b617c8062686121b882
Author: Doug Berger <opendmb@xxxxxxxxx>
Date: Mon Nov 11 04:32:04 2019 +0100
ARM: 8937/1: spectre-v2: remove Brahma-B53 from hardening
[ Upstream commit 4ae5061a19b550dfe25397843427ed2ebab16b16 ]
When the default processor handling was added to the function
cpu_v7_spectre_init() it only excluded other ARM implemented processor
cores. The Broadcom Brahma B53 core is not implemented by ARM so it
ended up falling through into the set of processors that attempt to use
the ARM_SMCCC_ARCH_WORKAROUND_1 service to harden the branch predictor.
Since this workaround is not necessary for the Brahma-B53 this commit
explicitly checks for it and prevents it from applying a branch
predictor hardening workaround.
Fixes: 10115105cb3a ("ARM: spectre-v2: add firmware based hardening")
Signed-off-by: Doug Berger <opendmb@xxxxxxxxx>
Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/arm/mm/proc-v7-bugs.c b/arch/arm/mm/proc-v7-bugs.c
index 9a07916af8dd..a6554fdb56c5 100644
--- a/arch/arm/mm/proc-v7-bugs.c
+++ b/arch/arm/mm/proc-v7-bugs.c
@@ -65,6 +65,9 @@ static void cpu_v7_spectre_init(void)
break;
#ifdef CONFIG_ARM_PSCI
+ case ARM_CPU_PART_BRAHMA_B53:
+ /* Requires no workaround */
+ break;
default:
/* Other ARM CPUs require no workaround */
if (read_cpuid_implementor() == ARM_CPU_IMP_ARM)
