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authorMarc Zyngier <marc.zyngier@arm.com>2019-04-15 16:21:24 -0500
committerWill Deacon <will.deacon@arm.com>2019-04-26 16:30:11 +0100
commit517953c2c47f9c00a002f588ac856a5bc70cede3 (patch)
treea49d9fa32f4bb7a764feb7cc73d5ed20d63558bd /arch/arm64/kernel/cpu_errata.c
parent73f38166095947f3b86b02fbed6bd592223a7ac8 (diff)
arm64: Use firmware to detect CPUs that are not affected by Spectre-v2
The SMCCC ARCH_WORKAROUND_1 service can indicate that although the firmware knows about the Spectre-v2 mitigation, this particular CPU is not vulnerable, and it is thus not necessary to call the firmware on this CPU. Let's use this information to our benefit. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> Reviewed-by: Andre Przywara <andre.przywara@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Tested-by: Stefan Wahren <stefan.wahren@i2se.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/kernel/cpu_errata.c')
-rw-r--r--arch/arm64/kernel/cpu_errata.c32
1 files changed, 23 insertions, 9 deletions
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 032f1a4dbea2..60cf87c4deb7 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -230,22 +230,36 @@ static int detect_harden_bp_fw(void)
case PSCI_CONDUIT_HVC:
arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
ARM_SMCCC_ARCH_WORKAROUND_1, &res);
- if ((int)res.a0 < 0)
+ switch ((int)res.a0) {
+ case 1:
+ /* Firmware says we're just fine */
+ return 0;
+ case 0:
+ cb = call_hvc_arch_workaround_1;
+ /* This is a guest, no need to patch KVM vectors */
+ smccc_start = NULL;
+ smccc_end = NULL;
+ break;
+ default:
return -1;
- cb = call_hvc_arch_workaround_1;
- /* This is a guest, no need to patch KVM vectors */
- smccc_start = NULL;
- smccc_end = NULL;
+ }
break;
case PSCI_CONDUIT_SMC:
arm_smccc_1_1_smc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
ARM_SMCCC_ARCH_WORKAROUND_1, &res);
- if ((int)res.a0 < 0)
+ switch ((int)res.a0) {
+ case 1:
+ /* Firmware says we're just fine */
+ return 0;
+ case 0:
+ cb = call_smc_arch_workaround_1;
+ smccc_start = __smccc_workaround_1_smc_start;
+ smccc_end = __smccc_workaround_1_smc_end;
+ break;
+ default:
return -1;
- cb = call_smc_arch_workaround_1;
- smccc_start = __smccc_workaround_1_smc_start;
- smccc_end = __smccc_workaround_1_smc_end;
+ }
break;
default: