Provide a hwcap to enable userspace to detect support for GCS.
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
Documentation/arch/arm64/elf_hwcaps.rst | 4 ++++
arch/arm64/include/asm/hwcap.h | 1 +
arch/arm64/include/uapi/asm/hwcap.h | 3 ++-
arch/arm64/kernel/cpufeature.c | 3 +++
arch/arm64/kernel/cpuinfo.c | 1 +
5 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/Documentation/arch/arm64/elf_hwcaps.rst b/Documentation/arch/arm64/elf_hwcaps.rst
index 694f67fa07d1..25b41ff74fa0 100644
--- a/Documentation/arch/arm64/elf_hwcaps.rst
+++ b/Documentation/arch/arm64/elf_hwcaps.rst
@@ -170,6 +170,10 @@ HWCAP_PACG
ID_AA64ISAR1_EL1.GPI == 0b0001, as described by
Documentation/arch/arm64/pointer-authentication.rst.
+HWCAP_GCS
+ Functionality implied by ID_AA64PFR1_EL1.GCS == 0b1, as
+ described by Documentation/arch/arm64/gcs.rst.
+
HWCAP2_DCPODP
Functionality implied by ID_AA64ISAR1_EL1.DPB == 0b0010.
diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h
index a775adddecf2..7bcf1347ca0b 100644
--- a/arch/arm64/include/asm/hwcap.h
+++ b/arch/arm64/include/asm/hwcap.h
@@ -92,6 +92,7 @@
#define KERNEL_HWCAP_SB __khwcap_feature(SB)
#define KERNEL_HWCAP_PACA __khwcap_feature(PACA)
#define KERNEL_HWCAP_PACG __khwcap_feature(PACG)
+#define KERNEL_HWCAP_GCS __khwcap_feature(GCS)
#define __khwcap2_feature(x) (const_ilog2(HWCAP2_ ## x) + 64)
#define KERNEL_HWCAP_DCPODP __khwcap2_feature(DCPODP)
diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h
index 055381b2c615..675642ec4d91 100644
--- a/arch/arm64/include/uapi/asm/hwcap.h
+++ b/arch/arm64/include/uapi/asm/hwcap.h
@@ -21,7 +21,7 @@
* HWCAP flags - for AT_HWCAP
*
* Bits 62 and 63 are reserved for use by libc.
- * Bits 32-61 are unallocated for potential use by libc.
+ * Bits 33-61 are unallocated for potential use by libc.
*/
#define HWCAP_FP (1 << 0)
#define HWCAP_ASIMD (1 << 1)
@@ -55,6 +55,7 @@
#define HWCAP_SB (1 << 29)
#define HWCAP_PACA (1 << 30)
#define HWCAP_PACG (1UL << 31)
+#define HWCAP_GCS (1UL << 32)
/*
* HWCAP2 flags - for AT_HWCAP2
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index d1e758e99e0a..b8655d55f318 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -3025,6 +3025,9 @@ 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 44718d0482b3..f2f92c6b1c85 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -80,6 +80,7 @@ static const char *const hwcap_str[] = {
[KERNEL_HWCAP_SB] = "sb",
[KERNEL_HWCAP_PACA] = "paca",
[KERNEL_HWCAP_PACG] = "pacg",
+ [KERNEL_HWCAP_GCS] = "gcs",
[KERNEL_HWCAP_DCPODP] = "dcpodp",
[KERNEL_HWCAP_SVE2] = "sve2",
[KERNEL_HWCAP_SVEAES] = "sveaes",
--
2.39.2
