[PATCH v12 17/39] arm64/hwcap: Add hwcap for GCS

[Mark Brown]

Provide a hwcap to enable userspace to detect support for GCS.

Reviewed-by: Thiago Jung Bauermann <thiago.bauermann at linaro.org>
Reviewed-by: Catalin Marinas <catalin.marinas at arm.com>
Signed-off-by: Mark Brown <broonie at kernel.org>
---
 Documentation/arch/arm64/elf_hwcaps.rst | 2 ++
 arch/arm64/include/asm/hwcap.h          | 1 +
 arch/arm64/include/uapi/asm/hwcap.h     | 1 +
 arch/arm64/kernel/cpufeature.c          | 3 +++
 arch/arm64/kernel/cpuinfo.c             | 1 +
 5 files changed, 8 insertions(+)

diff --git a/Documentation/arch/arm64/elf_hwcaps.rst b/Documentation/arch/arm64/elf_hwcaps.rst
index 448c1664879b..cf87be078f33 100644
--- a/Documentation/arch/arm64/elf_hwcaps.rst
+++ b/Documentation/arch/arm64/elf_hwcaps.rst
@@ -365,6 +365,8 @@ HWCAP2_SME_SF8DP2
 HWCAP2_SME_SF8DP4
     Functionality implied by ID_AA64SMFR0_EL1.SF8DP4 == 0b1.
 
+HWCAP2_GCS
+    Functionality implied by ID_AA64PFR1_EL1.GCS == 0b1
 
 4. Unused AT_HWCAP bits
 -----------------------
diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h
index 4edd3b61df11..fd7e162e7e39 100644
--- a/arch/arm64/include/asm/hwcap.h
+++ b/arch/arm64/include/asm/hwcap.h
@@ -157,6 +157,7 @@
 #define KERNEL_HWCAP_SME_SF8FMA		__khwcap2_feature(SME_SF8FMA)
 #define KERNEL_HWCAP_SME_SF8DP4		__khwcap2_feature(SME_SF8DP4)
 #define KERNEL_HWCAP_SME_SF8DP2		__khwcap2_feature(SME_SF8DP2)
+#define KERNEL_HWCAP_GCS		__khwcap2_feature(GCS)
 
 /*
  * This yields a mask that user programs can use to figure out what
diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h
index 285610e626f5..328fb7843e2f 100644
--- a/arch/arm64/include/uapi/asm/hwcap.h
+++ b/arch/arm64/include/uapi/asm/hwcap.h
@@ -122,5 +122,6 @@
 #define HWCAP2_SME_SF8FMA	(1UL << 60)
 #define HWCAP2_SME_SF8DP4	(1UL << 61)
 #define HWCAP2_SME_SF8DP2	(1UL << 62)
+#define HWCAP2_GCS		(1UL << 63)
 
 #endif /* _UAPI__ASM_HWCAP_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 315bd7be1106..e3e8290a4447 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -2994,6 +2994,9 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
 	HWCAP_CAP(ID_AA64ZFR0_EL1, I8MM, IMP, CAP_HWCAP, KERNEL_HWCAP_SVEI8MM),
 	HWCAP_CAP(ID_AA64ZFR0_EL1, F32MM, IMP, CAP_HWCAP, KERNEL_HWCAP_SVEF32MM),
 	HWCAP_CAP(ID_AA64ZFR0_EL1, F64MM, IMP, CAP_HWCAP, KERNEL_HWCAP_SVEF64MM),
+#endif
+#ifdef CONFIG_ARM64_GCS
+	HWCAP_CAP(ID_AA64PFR1_EL1, GCS, IMP, CAP_HWCAP, KERNEL_HWCAP_GCS),
 #endif
 	HWCAP_CAP(ID_AA64PFR1_EL1, SSBS, SSBS2, CAP_HWCAP, KERNEL_HWCAP_SSBS),
 #ifdef CONFIG_ARM64_BTI
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 09eeaa24d456..2f539e3101ee 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -143,6 +143,7 @@ static const char *const hwcap_str[] = {
 	[KERNEL_HWCAP_SME_SF8FMA]	= "smesf8fma",
 	[KERNEL_HWCAP_SME_SF8DP4]	= "smesf8dp4",
 	[KERNEL_HWCAP_SME_SF8DP2]	= "smesf8dp2",
+	[KERNEL_HWCAP_GCS]		= "gcs",
 };
 
 #ifdef CONFIG_COMPAT

-- 
2.39.2