arm64: Detect FEAT_SCTLR2

KVM is about to pick up support for SCTLR2. Add cpucap for later use in
the guest/host context switch hot path.

Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250708172532.1699409-2-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index b34044e20128b367efa22527387a566456e83992..b85be598cb1708138da6c1eea6aaf1e41f1a26fb 100644 (file)
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -500,6 +500,7 @@ static const struct arm64_ftr_bits ftr_id_aa64mmfr3[] = {
        ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_POE),
                       FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR3_EL1_S1POE_SHIFT, 4, 0),
        ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR3_EL1_S1PIE_SHIFT, 4, 0),
+       ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR3_EL1_SCTLRX_SHIFT, 4, 0),
        ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR3_EL1_TCRX_SHIFT, 4, 0),
        ARM64_FTR_END,
 };
@@ -3061,6 +3062,13 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
                .matches = has_pmuv3,
        },
 #endif
+       {
+               .desc = "SCTLR2",
+               .capability = ARM64_HAS_SCTLR2,
+               .type = ARM64_CPUCAP_SYSTEM_FEATURE,
+               .matches = has_cpuid_feature,
+               ARM64_CPUID_FIELDS(ID_AA64MMFR3_EL1, SCTLRX, IMP)
+       },
        {},
 };
 

diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
index 10effd4cff6b4efbd1bc4f7d4d515691b2ece478..24d57e309f277a7d0d3f515051ece9dc8f53c800 100644 (file)
--- a/arch/arm64/tools/cpucaps
+++ b/arch/arm64/tools/cpucaps
@@ -49,6 +49,7 @@ HAS_PAN
 HAS_PMUV3
 HAS_S1PIE
 HAS_S1POE
+HAS_SCTLR2
 HAS_RAS_EXTN
 HAS_RNG
 HAS_SB