[PATCH 4/9] arm64: Convert CONFIG_ARM64_SME to FTR_CONFIG()

Marc Zyngier maz at kernel.org
Thu Feb 19 11:55:27 PST 2026


While CONFIG_ARM64_SME=n prevents userspace from using SME,
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_SME=n.

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

Signed-off-by: Marc Zyngier <maz at kernel.org>
---
 arch/arm64/kernel/cpufeature.c | 48 +++++++++++++++++-----------------
 1 file changed, 24 insertions(+), 24 deletions(-)

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 9f631658de4b3..3d7083280cdde 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -310,7 +310,7 @@ static const struct arm64_ftr_bits ftr_id_aa64pfr1[] = {
 	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_GCS),
 		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_EL1_GCS_SHIFT, 4, 0),
 	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_EL1_MTE_frac_SHIFT, 4, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       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),
@@ -358,51 +358,51 @@ static const struct arm64_ftr_bits ftr_id_aa64zfr0[] = {
 };
 
 static const struct arm64_ftr_bits ftr_id_aa64smfr0[] = {
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_FA64_SHIFT, 1, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_LUTv2_SHIFT, 1, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_SMEver_SHIFT, 4, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_I16I64_SHIFT, 4, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_F64F64_SHIFT, 1, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_I16I32_SHIFT, 4, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_B16B16_SHIFT, 1, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_F16F16_SHIFT, 1, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_F8F16_SHIFT, 1, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_F8F32_SHIFT, 1, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_I8I32_SHIFT, 4, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_F16F32_SHIFT, 1, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_B16F32_SHIFT, 1, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_BI32I32_SHIFT, 1, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_F32F32_SHIFT, 1, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_SF8FMA_SHIFT, 1, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_SF8DP4_SHIFT, 1, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_SF8DP2_SHIFT, 1, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_SBitPerm_SHIFT, 1, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_AES_SHIFT, 1, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_SFEXPA_SHIFT, 1, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_STMOP_SHIFT, 1, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+	ARM64_FTR_BITS(FTR_CONFIG(CONFIG_ARM64_SME, VISIBLE, ALL_HIDDEN),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_SMOP4_SHIFT, 1, 0),
 	ARM64_FTR_END,
 };
-- 
2.47.3




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