[PATCH v2 01/27] arm64: Detect FEAT_SCTLR2

[Oliver Upton <oliver.upton@linux.dev>]

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

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
 arch/arm64/kernel/cpufeature.c | 8 ++++++++
 arch/arm64/tools/cpucaps       | 1 +
 2 files changed, 9 insertions(+)

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index b34044e20128..b85be598cb17 100644
--- 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 10effd4cff6b..24d57e309f27 100644
--- 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
-- 
2.39.5