[PATCH 6/9] arm64: Convert CONFIG_ARM64_MTE to FTR_CONFIG()

Marc Zyngier
2026-02-19T19:55:48Z

While CONFIG_ARM64_MTE=n prevents userspace from using MTE,
the sanitised ID registers still advertise the feature.

Make it clear that nothing in the kernel should rely on this by
marking the feature as hidden for all when CONFIG_ARM64_MTE=n.

This is functionnaly equivalent to using arm64.nomte on the kernel
command-line.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/kernel/cpufeature.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index ca4aae48ace66..2b9d03c9564e6 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -314,7 +314,7 @@ static const struct arm64_ftr_bits ftr_id_aa64pfr1[] = {
FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_EL1_SME_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_EL1_MPAM_frac_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_EL1_RAS_frac_SHIFT, 4, 0),
- ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_MTE),
+ ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_MTE, VISIBLE, ALL_HIDDEN),
FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_EL1_MTE_SHIFT, 4, ID_AA64PFR1_EL1_MTE_NI),
ARM64_FTR_BITS(FTR_VISIBLE, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR1_EL1_SSBS_SHIFT, 4, ID_AA64PFR1_EL1_SSBS_NI),
ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_BTI),
--
2.47.3