[PATCH 10/27] arm64: Add feature detection for fine grained traps

[Marc Zyngier]

From: Mark Brown <broonie at kernel.org>

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>
Signed-off-by: Marc Zyngier <maz at kernel.org>
Link: https://lore.kernel.org/r/20230301-kvm-arm64-fgt-v4-1-1bf8d235ac1f@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 f9d456fe132d..0768f98c49cc 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -2627,6 +2627,17 @@ 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 c80ed4f3cbce..c3f06fdef609 100644
--- a/arch/arm64/tools/cpucaps
+++ b/arch/arm64/tools/cpucaps
@@ -26,6 +26,7 @@ HAS_ECV
 HAS_ECV_CNTPOFF
 HAS_EPAN
 HAS_EVT
+HAS_FGT
 HAS_GENERIC_AUTH
 HAS_GENERIC_AUTH_ARCH_QARMA3
 HAS_GENERIC_AUTH_ARCH_QARMA5
-- 
2.34.1