diff mbox series

[02/19] arm64: Run ARCH_WORKAROUND_1 enabling code on all CPUs

Message ID 20200918164729.31994-3-will@kernel.org (mailing list archive)
State New, archived
Headers show
Series Fix and rewrite arm64 spectre mitigations | expand

Commit Message

Will Deacon Sept. 18, 2020, 4:47 p.m. UTC 
From: Marc Zyngier <maz@kernel.org>

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>
---
 arch/arm64/kernel/cpu_errata.c | 8 ++++++++
 1 file changed, 8 insertions(+)

Comments

Sasha Levin Sept. 21, 2020, 12:54 p.m. UTC | #1 
Hi

[This is an automated email]

This commit has been processed because it contains a "Fixes:" tag
fixing commit: 73f381660959 ("arm64: Advertise mitigation of Spectre-v2, or lack thereof").

The bot has tested the following trees: v5.8.10, v5.4.66, v4.19.146, v4.14.198.

v5.8.10: Build OK!
v5.4.66: Build OK!
v4.19.146: Build OK!
v4.14.198: Failed to apply! Possible dependencies:
    4b472ffd1513 ("arm64: Enable ARM64_HARDEN_EL2_VECTORS on Cortex-A57 and A72")
    631989303b06 ("Merge tag 'kvmarm-for-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD")
    8892b71885df ("arm64: capabilities: Rework EL2 vector hardening entry")
    93916beb7014 ("arm64: Enable workaround for Cavium TX2 erratum 219 when running SMT")
    95b861a4a6d9 ("arm64: arch_timer: Add workaround for ARM erratum 1188873")
    969f5ea62757 ("arm64: errata: Add workaround for Cortex-A76 erratum #1463225")
    a457b0f7f50d ("arm64: Add configuration/documentation for Cortex-A76 erratum 1165522")
    dc6ed61d2f82 ("arm64: Add temporary ERRATA_MIDR_ALL_VERSIONS compatibility macro")
    e03a4e5bb743 ("arm64: Add silicon-errata.txt entry for ARM erratum 1188873")


NOTE: The patch will not be queued to stable trees until it is upstream.

How should we proceed with this patch?
diff mbox series

Patch

diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 88966496806a..3fe64bf5a58d 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -599,6 +599,12 @@  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),
@@ -890,9 +896,11 @@  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_RANDOMIZE_BASE
 	{