Expose a HWCAP and ID_AA64MMFR3_EL1_S1POE to userspace, so they can be used to
check if the CPU supports the feature.
Signed-off-by: Joey Gouly <joey.go...@arm.com>
Cc: Catalin Marinas <catalin.mari...@arm.com>
Cc: Will Deacon <w...@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 | 14 ++++++++++++++
arch/arm64/kernel/cpuinfo.c | 1 +
5 files changed, 20 insertions(+)
diff --git a/Documentation/arch/arm64/elf_hwcaps.rst
b/Documentation/arch/arm64/elf_hwcaps.rst
index ced7b335e2e0..fe7350a66cea 100644
--- a/Documentation/arch/arm64/elf_hwcaps.rst
+++ b/Documentation/arch/arm64/elf_hwcaps.rst
@@ -317,6 +317,9 @@ HWCAP2_LRCPC3
HWCAP2_LSE128
Functionality implied by ID_AA64ISAR0_EL1.Atomic == 0b0011.
+HWCAP2_POE
+ Functionality implied by ID_AA64MMFR3_EL1.S1POE == 0b0001.
+
4. Unused AT_HWCAP bits
-----------------------
diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h
index cd71e09ea14d..9a1aa1e5e25c 100644
--- a/arch/arm64/include/asm/hwcap.h
+++ b/arch/arm64/include/asm/hwcap.h
@@ -142,6 +142,7 @@
#define KERNEL_HWCAP_SVE_B16B16 __khwcap2_feature(SVE_B16B16)
#define KERNEL_HWCAP_LRCPC3 __khwcap2_feature(LRCPC3)
#define KERNEL_HWCAP_LSE128 __khwcap2_feature(LSE128)
+#define KERNEL_HWCAP_POE __khwcap2_feature(POE)
/*
* 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 5023599fa278..69f09521b553 100644
--- a/arch/arm64/include/uapi/asm/hwcap.h
+++ b/arch/arm64/include/uapi/asm/hwcap.h
@@ -107,5 +107,6 @@
#define HWCAP2_SVE_B16B16 (1UL << 45)
#define HWCAP2_LRCPC3 (1UL << 46)
#define HWCAP2_LSE128 (1UL << 47)
+#define HWCAP2_POE (1UL << 48)
#endif /* _UAPI__ASM_HWCAP_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 00b6d516ed3f..02169cb3b84b 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -402,6 +402,8 @@ static const struct arm64_ftr_bits ftr_id_aa64mmfr2[] = {
};
static const struct arm64_ftr_bits ftr_id_aa64mmfr3[] = {
+ ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_POE),
+ FTR_NONSTRICT, FTR_LOWER_SAFE,
ID_AA64MMFR3_EL1_S1POE_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE,
ID_AA64MMFR3_EL1_S1PIE_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE,
ID_AA64MMFR3_EL1_TCRX_SHIFT, 4, 0),
ARM64_FTR_END,
@@ -2242,6 +2244,14 @@ static void cpu_enable_mops(const struct
arm64_cpu_capabilities *__unused)
sysreg_clear_set(sctlr_el1, 0, SCTLR_EL1_MSCEn);
}
+#ifdef CONFIG_ARM64_POE
+static void cpu_enable_poe(const struct arm64_cpu_capabilities *__unused)
+{
+ sysreg_clear_set(REG_TCR2_EL1, 0, TCR2_EL1x_E0POE);
+ sysreg_clear_set(CPACR_EL1, 0, CPACR_ELx_E0POE);
+}
+#endif
+
/* Internal helper functions to match cpu capability type */
static bool
cpucap_late_cpu_optional(const struct arm64_cpu_capabilities *cap)
@@ -2737,6 +2747,7 @@ static const struct arm64_cpu_capabilities
arm64_features[] = {
.capability = ARM64_HAS_S1POE,
.type = ARM64_CPUCAP_BOOT_CPU_FEATURE,
.matches = has_cpuid_feature,
+ .cpu_enable = cpu_enable_poe,
ARM64_CPUID_FIELDS(ID_AA64MMFR3_EL1, S1POE, IMP)
},
#endif
@@ -2889,6 +2900,9 @@ static const struct arm64_cpu_capabilities
arm64_elf_hwcaps[] = {
HWCAP_CAP(ID_AA64SMFR0_EL1, BI32I32, IMP, CAP_HWCAP,
KERNEL_HWCAP_SME_BI32I32),
HWCAP_CAP(ID_AA64SMFR0_EL1, F32F32, IMP, CAP_HWCAP,
KERNEL_HWCAP_SME_F32F32),
#endif /* CONFIG_ARM64_SME */
+#ifdef CONFIG_ARM64_POE
+ HWCAP_CAP(ID_AA64MMFR3_EL1, S1POE, IMP, CAP_HWCAP, KERNEL_HWCAP_POE),
+#endif
{},
};
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index a257da7b56fe..5515c50f5219 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -130,6 +130,7 @@ static const char *const hwcap_str[] = {
[KERNEL_HWCAP_SVE_B16B16] = "sveb16b16",
[KERNEL_HWCAP_LRCPC3] = "lrcpc3",
[KERNEL_HWCAP_LSE128] = "lse128",
+ [KERNEL_HWCAP_POE] = "poe",
};
#ifdef CONFIG_COMPAT
--
2.25.1
