From: Marc Zyngier maz@kernel.org
stable inclusion from linux-4.19.155 commit d953cd3fb149a999534ff48af323eb091fd5aa3b
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commit 18fce56134c987e5b4eceddafdbe4b00c07e2ae1 upstream.
Commit 73f381660959 ("arm64: Advertise mitigation of Spectre-v2, or lack thereof") changed the way we deal with ARCH_WORKAROUND_1, by moving most of the enabling code to the .matches() callback.
This has the unfortunate effect that the workaround gets only enabled on the first affected CPU, and no other.
In order to address this, forcefully call the .matches() callback from a .cpu_enable() callback, which brings us back to the original behaviour.
Fixes: 73f381660959 ("arm64: Advertise mitigation of Spectre-v2, or lack thereof") Cc: stable@vger.kernel.org Reviewed-by: Suzuki K Poulose suzuki.poulose@arm.com Signed-off-by: Marc Zyngier maz@kernel.org Signed-off-by: Will Deacon will@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com --- arch/arm64/kernel/cpu_errata.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index 5f2c30ae82ac..c0b2ef5e7ea3 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -647,6 +647,12 @@ check_branch_predictor(const struct arm64_cpu_capabilities *entry, int scope) return (need_wa > 0); }
+static void +cpu_enable_branch_predictor_hardening(const struct arm64_cpu_capabilities *cap) +{ + cap->matches(cap, SCOPE_LOCAL_CPU); +} + static const __maybe_unused struct midr_range tx2_family_cpus[] = { MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN), MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2), @@ -829,9 +835,11 @@ const struct arm64_cpu_capabilities arm64_errata[] = { }, #endif { + .desc = "Branch predictor hardening", .capability = ARM64_HARDEN_BRANCH_PREDICTOR, .type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM, .matches = check_branch_predictor, + .cpu_enable = cpu_enable_branch_predictor_hardening, }, #ifdef CONFIG_HARDEN_EL2_VECTORS {