From fe24ee783220943966f4548c1d770e3985ddf24d Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Thu, 13 Dec 2018 13:47:38 +0000 Subject: [PATCH] arm64: kpti: Whitelist Cortex-A CPUs that don't implement the CSV3 field commit 2a355ec25729053bb9a1a89b6c1d1cdd6c3b3fb1 upstream. While the CSV3 field of the ID_AA64_PFR0 CPU ID register can be checked to see if a CPU is susceptible to Meltdown and therefore requires kpti to be enabled, existing CPUs do not implement this field. We therefore whitelist all unaffected Cortex-A CPUs that do not implement the CSV3 field. Signed-off-by: Will Deacon Signed-off-by: Niklas Cassel Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/cpufeature.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 3312d46fa29e..57ec681a8f11 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -838,6 +838,11 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry, switch (read_cpuid_id() & MIDR_CPU_MODEL_MASK) { case MIDR_CAVIUM_THUNDERX2: case MIDR_BRCM_VULCAN: + case MIDR_CORTEX_A53: + case MIDR_CORTEX_A55: + case MIDR_CORTEX_A57: + case MIDR_CORTEX_A72: + case MIDR_CORTEX_A73: return false; } -- 2.20.1