[PATCH v4 1/2] arm64: Add feature detection for fine grained traps

[Mark Brown]

In order to allow us to have shared code for managing fine grained traps
for KVM guests add it as a detected feature rather than relying on it
being a dependency of other features.

Acked-by: Catalin Marinas <catalin.marinas at arm.com>
Signed-off-by: Mark Brown <broonie at kernel.org>
---
 arch/arm64/kernel/cpufeature.c | 11 +++++++++++
 arch/arm64/tools/cpucaps       |  1 +
 2 files changed, 12 insertions(+)

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 7d7128c65161..a103ec454f02 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -2591,6 +2591,17 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
 		.matches = has_cpuid_feature,
 		ARM64_CPUID_FIELDS(ID_AA64ISAR1_EL1, LRCPC, IMP)
 	},
+	{
+		.desc = "Fine Grained Traps",
+		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
+		.capability = ARM64_HAS_FGT,
+		.sys_reg = SYS_ID_AA64MMFR0_EL1,
+		.sign = FTR_UNSIGNED,
+		.field_pos = ID_AA64MMFR0_EL1_FGT_SHIFT,
+		.field_width = 4,
+		.min_field_value = 1,
+		.matches = has_cpuid_feature,
+	},
 #ifdef CONFIG_ARM64_SME
 	{
 		.desc = "Scalable Matrix Extension",
diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
index 40ba95472594..bd93b3446e34 100644
--- a/arch/arm64/tools/cpucaps
+++ b/arch/arm64/tools/cpucaps
@@ -25,6 +25,7 @@ HAS_E0PD
 HAS_ECV
 HAS_ECV_CNTPOFF
 HAS_EPAN
+HAS_FGT
 HAS_GENERIC_AUTH
 HAS_GENERIC_AUTH_ARCH_QARMA3
 HAS_GENERIC_AUTH_ARCH_QARMA5

-- 
2.30.2