From: Marc Zyngier <marc.zyngier@arm.com>
Date: Fri, 9 Mar 2018 15:40:50 +0000
Subject: arm64: Relax ARM_SMCCC_ARCH_WORKAROUND_1 discovery
Git-commit: e21da1c992007594d391e7b301779cf30f438691
Patch-mainline: v4.16-rc5
References: bsc#1088051
A recent update to the ARM SMCCC ARCH_WORKAROUND_1 specification
allows firmware to return a non zero, positive value to describe
that although the mitigation is implemented at the higher exception
level, the CPU on which the call is made is not affected.
Let's relax the check on the return value from ARCH_WORKAROUND_1
so that we only error out if the returned value is negative.
Fixes: b092201e0020 ("arm64: Add ARM_SMCCC_ARCH_WORKAROUND_1 BP hardening support")
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Matthias Brugger <mbrugger@suse.com>
---
arch/arm64/kernel/cpu_errata.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 52f15cd896e1..b5a28336c077 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -178,7 +178,7 @@ static int enable_smccc_arch_workaround_1(void *data)
case PSCI_CONDUIT_HVC:
arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
ARM_SMCCC_ARCH_WORKAROUND_1, &res);
- if (res.a0)
+ if ((int)res.a0 < 0)
return 0;
cb = call_hvc_arch_workaround_1;
smccc_start = __smccc_workaround_1_hvc_start;
@@ -188,7 +188,7 @@ static int enable_smccc_arch_workaround_1(void *data)
case PSCI_CONDUIT_SMC:
arm_smccc_1_1_smc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
ARM_SMCCC_ARCH_WORKAROUND_1, &res);
- if (res.a0)
+ if ((int)res.a0 < 0)
return 0;
cb = call_smc_arch_workaround_1;
smccc_start = __smccc_workaround_1_smc_start;
--
2.16.2