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ARM: 8937/1: spectre-v2: remove Brahma-B53 from hardening

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[ Upstream commit 4ae5061a19 ]

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: 10115105cb ("ARM: spectre-v2: add firmware based hardening")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Doug Berger 2019-11-11 04:32:04 +01:00 committed by Greg Kroah-Hartman
parent 0822e4dc6a
commit 87d9d4cdb1
1 changed files with 3 additions and 0 deletions
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3
arch/arm/mm/proc-v7-bugs.c
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@ -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)