[PATCH 4.14 078/195] [Variant 2/Spectre-v2] arm64: Branch predictor hardening for Cavium ThunderX2

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jayachandran C <jnair@xxxxxxxxxxxxxxxxxx>


Commit f3d795d9b360 upstream.

Use PSCI based mitigation for speculative execution attacks targeting
the branch predictor. We use the same mechanism as the one used for
Cortex-A CPUs, we expect the PSCI version call to have a side effect
of clearing the BTBs.

Acked-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Jayachandran C <jnair@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 arch/arm64/kernel/cpu_errata.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -359,6 +359,16 @@ const struct arm64_cpu_capabilities arm6
 		.capability = ARM64_HARDEN_BP_POST_GUEST_EXIT,
 		MIDR_ALL_VERSIONS(MIDR_QCOM_FALKOR_V1),
 	},
+	{
+		.capability = ARM64_HARDEN_BRANCH_PREDICTOR,
+		MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN),
+		.enable = enable_psci_bp_hardening,
+	},
+	{
+		.capability = ARM64_HARDEN_BRANCH_PREDICTOR,
+		MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2),
+		.enable = enable_psci_bp_hardening,
+	},
 #endif
 	{
 	}