[PATCH v5 16/37] arm64/hwcap: Add hwcap for GCS

Mark Brown
2023-08-22T14:05:54Z

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

Signed-off-by: Mark Brown <broonie@kernel.org>
---
Documentation/arch/arm64/elf_hwcaps.rst | 3 +++
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, 9 insertions(+)

diff --git a/Documentation/arch/arm64/elf_hwcaps.rst b/Documentation/arch/arm64/elf_hwcaps.rst
index 8c8addb4194c..75f3960cad39 100644
--- a/Documentation/arch/arm64/elf_hwcaps.rst
+++ b/Documentation/arch/arm64/elf_hwcaps.rst
@@ -305,6 +305,9 @@ HWCAP2_SMEF16F16
HWCAP2_MOPS
Functionality implied by ID_AA64ISAR2_EL1.MOPS == 0b0001.

+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 692b1ec663b2..39f397a2b5b2 100644
--- a/arch/arm64/include/asm/hwcap.h
+++ b/arch/arm64/include/asm/hwcap.h
@@ -138,6 +138,7 @@
#define KERNEL_HWCAP_SME_B16B16 __khwcap2_feature(SME_B16B16)
#define KERNEL_HWCAP_SME_F16F16 __khwcap2_feature(SME_F16F16)
#define KERNEL_HWCAP_MOPS __khwcap2_feature(MOPS)
+#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 a2cac4305b1e..7510c35e6864 100644
--- a/arch/arm64/include/uapi/asm/hwcap.h
+++ b/arch/arm64/include/uapi/asm/hwcap.h
@@ -103,5 +103,6 @@
#define HWCAP2_SME_B16B16 (1UL << 41)
#define HWCAP2_SME_F16F16 (1UL << 42)
#define HWCAP2_MOPS (1UL << 43)
+#define HWCAP2_GCS (1UL << 44)

#endif /* _UAPI__ASM_HWCAP_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 91a14a6ccb04..7b46e01140c4 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -2840,6 +2840,9 @@ 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 58622dc85917..451fbbeffa39 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -126,6 +126,7 @@ static const char *const hwcap_str[] = {
[KERNEL_HWCAP_SME_B16B16] = "smeb16b16",
[KERNEL_HWCAP_SME_F16F16] = "smef16f16",
[KERNEL_HWCAP_MOPS] = "mops",
+ [KERNEL_HWCAP_GCS] = "gcs",
};

#ifdef CONFIG_COMPAT

--
2.30.2