[PATCH v6 13/37] arm64/sme: Basic enumeration support
Mark Brown
broonie at kernel.org
Mon Nov 15 07:28:11 PST 2021
This patch introduces basic cpufeature support for discovering the presence
of the Scalable Matrix Extension and reporting hwcaps for the detected
features.
Signed-off-by: Mark Brown <broonie at kernel.org>
---
Documentation/arm64/elf_hwcaps.rst | 33 +++++++++++++++++
arch/arm64/include/asm/cpu.h | 1 +
arch/arm64/include/asm/cpufeature.h | 12 +++++++
arch/arm64/include/asm/fpsimd.h | 2 ++
arch/arm64/include/asm/hwcap.h | 8 +++++
arch/arm64/include/uapi/asm/hwcap.h | 8 +++++
arch/arm64/kernel/cpufeature.c | 55 +++++++++++++++++++++++++++++
arch/arm64/kernel/cpuinfo.c | 9 +++++
arch/arm64/kernel/fpsimd.c | 30 ++++++++++++++++
arch/arm64/tools/cpucaps | 2 ++
10 files changed, 160 insertions(+)
diff --git a/Documentation/arm64/elf_hwcaps.rst b/Documentation/arm64/elf_hwcaps.rst
index af106af8e1c0..155f726816f9 100644
--- a/Documentation/arm64/elf_hwcaps.rst
+++ b/Documentation/arm64/elf_hwcaps.rst
@@ -251,6 +251,39 @@ HWCAP2_ECV
Functionality implied by ID_AA64MMFR0_EL1.ECV == 0b0001.
+HWCAP2_SME
+
+ Functionality implied by ID_AA64PFR1_EL1.SME == 0b0001, as described
+ by Documentation/arm64/sme.rst.
+
+HWCAP2_SME_I16I64
+
+ Functionality implied by ID_AA64SMFR0_EL1.I16I64 == 0b1111.
+
+HWCAP2_SME_F64F64
+
+ Functionality implied by ID_AA64SMFR0_EL1.F64F64 == 0b1.
+
+HWCAP2_SME_I8I32
+
+ Functionality implied by ID_AA64SMFR0_EL1.I8I32 == 0b1111.
+
+HWCAP2_SME_F16F32
+
+ Functionality implied by ID_AA64SMFR0_EL1.F16F32 == 0b1.
+
+HWCAP2_SME_B16F32
+
+ Functionality implied by ID_AA64SMFR0_EL1.B16F32 == 0b1.
+
+HWCAP2_SME_F32F32
+
+ Functionality implied by ID_AA64SMFR0_EL1.F32F32 == 0b1.
+
+HWCAP2_SME_FA64
+
+ Functionality implied by ID_AA64SMFR0_EL1.FA64 == 0b1.
+
4. Unused AT_HWCAP bits
-----------------------
diff --git a/arch/arm64/include/asm/cpu.h b/arch/arm64/include/asm/cpu.h
index 0f6d16faa540..667b66fe1a53 100644
--- a/arch/arm64/include/asm/cpu.h
+++ b/arch/arm64/include/asm/cpu.h
@@ -57,6 +57,7 @@ struct cpuinfo_arm64 {
u64 reg_id_aa64pfr0;
u64 reg_id_aa64pfr1;
u64 reg_id_aa64zfr0;
+ u64 reg_id_aa64smfr0;
struct cpuinfo_32bit aarch32;
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index ef6be92b1921..079e9f15c5eb 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -727,6 +727,18 @@ static __always_inline bool system_supports_sve(void)
cpus_have_const_cap(ARM64_SVE);
}
+static __always_inline bool system_supports_sme(void)
+{
+ return IS_ENABLED(CONFIG_ARM64_SME) &&
+ cpus_have_const_cap(ARM64_SME);
+}
+
+static __always_inline bool system_supports_fa64(void)
+{
+ return IS_ENABLED(CONFIG_ARM64_SME) &&
+ cpus_have_const_cap(ARM64_SME_FA64);
+}
+
static __always_inline bool system_supports_cnp(void)
{
return IS_ENABLED(CONFIG_ARM64_CNP) &&
diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h
index cb24385e3632..d5f2825a2412 100644
--- a/arch/arm64/include/asm/fpsimd.h
+++ b/arch/arm64/include/asm/fpsimd.h
@@ -74,6 +74,8 @@ extern void sve_set_vq(unsigned long vq_minus_1);
struct arm64_cpu_capabilities;
extern void sve_kernel_enable(const struct arm64_cpu_capabilities *__unused);
+extern void sme_kernel_enable(const struct arm64_cpu_capabilities *__unused);
+extern void fa64_kernel_enable(const struct arm64_cpu_capabilities *__unused);
extern u64 read_zcr_features(void);
diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h
index b100e0055eab..dc008749e746 100644
--- a/arch/arm64/include/asm/hwcap.h
+++ b/arch/arm64/include/asm/hwcap.h
@@ -106,6 +106,14 @@
#define KERNEL_HWCAP_BTI __khwcap2_feature(BTI)
#define KERNEL_HWCAP_MTE __khwcap2_feature(MTE)
#define KERNEL_HWCAP_ECV __khwcap2_feature(ECV)
+#define KERNEL_HWCAP_SME __khwcap2_feature(SME)
+#define KERNEL_HWCAP_SME_I16I64 __khwcap2_feature(SME_I16I64)
+#define KERNEL_HWCAP_SME_F64F64 __khwcap2_feature(SME_F64F64)
+#define KERNEL_HWCAP_SME_I8I32 __khwcap2_feature(SME_I8I32)
+#define KERNEL_HWCAP_SME_F16F32 __khwcap2_feature(SME_F16F32)
+#define KERNEL_HWCAP_SME_B16F32 __khwcap2_feature(SME_B16F32)
+#define KERNEL_HWCAP_SME_F32F32 __khwcap2_feature(SME_F32F32)
+#define KERNEL_HWCAP_SME_FA64 __khwcap2_feature(SME_FA64)
/*
* 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 7b23b16f21ce..6f8ca04b6566 100644
--- a/arch/arm64/include/uapi/asm/hwcap.h
+++ b/arch/arm64/include/uapi/asm/hwcap.h
@@ -76,5 +76,13 @@
#define HWCAP2_BTI (1 << 17)
#define HWCAP2_MTE (1 << 18)
#define HWCAP2_ECV (1 << 19)
+#define HWCAP2_SME (1 << 20)
+#define HWCAP2_SME_I16I64 (1 << 21)
+#define HWCAP2_SME_F64F64 (1 << 22)
+#define HWCAP2_SME_I8I32 (1 << 23)
+#define HWCAP2_SME_F16F32 (1 << 24)
+#define HWCAP2_SME_B16F32 (1 << 25)
+#define HWCAP2_SME_F32F32 (1 << 26)
+#define HWCAP2_SME_FA64 (1 << 27)
#endif /* _UAPI__ASM_HWCAP_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 81824c7ea74f..3cf60819c354 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -246,6 +246,7 @@ static const struct arm64_ftr_bits ftr_id_aa64pfr0[] = {
};
static const struct arm64_ftr_bits ftr_id_aa64pfr1[] = {
+ ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_SME_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_MPAMFRAC_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_RASFRAC_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_MTE),
@@ -278,6 +279,24 @@ static const struct arm64_ftr_bits ftr_id_aa64zfr0[] = {
ARM64_FTR_END,
};
+static const struct arm64_ftr_bits ftr_id_aa64smfr0[] = {
+ ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+ FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_FA64_SHIFT, 1, 0),
+ ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+ FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_I16I64_SHIFT, 4, 0),
+ ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+ FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_F64F64_SHIFT, 1, 0),
+ ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+ FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_I8I32_SHIFT, 4, 0),
+ ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+ FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_F16F32_SHIFT, 1, 0),
+ ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+ FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_B16F32_SHIFT, 1, 0),
+ ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+ FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_F32F32_SHIFT, 1, 0),
+ ARM64_FTR_END,
+};
+
static const struct arm64_ftr_bits ftr_id_aa64mmfr0[] = {
ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_ECV_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_FGT_SHIFT, 4, 0),
@@ -628,6 +647,7 @@ static const struct __ftr_reg_entry {
ARM64_FTR_REG_OVERRIDE(SYS_ID_AA64PFR1_EL1, ftr_id_aa64pfr1,
&id_aa64pfr1_override),
ARM64_FTR_REG(SYS_ID_AA64ZFR0_EL1, ftr_id_aa64zfr0),
+ ARM64_FTR_REG(SYS_ID_AA64SMFR0_EL1, ftr_id_aa64smfr0),
/* Op1 = 0, CRn = 0, CRm = 5 */
ARM64_FTR_REG(SYS_ID_AA64DFR0_EL1, ftr_id_aa64dfr0),
@@ -939,6 +959,7 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
init_cpu_ftr_reg(SYS_ID_AA64PFR0_EL1, info->reg_id_aa64pfr0);
init_cpu_ftr_reg(SYS_ID_AA64PFR1_EL1, info->reg_id_aa64pfr1);
init_cpu_ftr_reg(SYS_ID_AA64ZFR0_EL1, info->reg_id_aa64zfr0);
+ init_cpu_ftr_reg(SYS_ID_AA64SMFR0_EL1, info->reg_id_aa64smfr0);
if (id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0))
init_32bit_cpu_features(&info->aarch32);
@@ -2370,6 +2391,30 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
.matches = has_cpuid_feature,
.min_field_value = 1,
},
+#ifdef CONFIG_ARM64_SME
+ {
+ .desc = "Scalable Matrix Extension",
+ .type = ARM64_CPUCAP_SYSTEM_FEATURE,
+ .capability = ARM64_SME,
+ .sys_reg = SYS_ID_AA64PFR1_EL1,
+ .sign = FTR_UNSIGNED,
+ .field_pos = ID_AA64PFR1_SME_SHIFT,
+ .min_field_value = ID_AA64PFR1_SME,
+ .matches = has_cpuid_feature,
+ .cpu_enable = sme_kernel_enable,
+ },
+ {
+ .desc = "FA64",
+ .type = ARM64_CPUCAP_SYSTEM_FEATURE,
+ .capability = ARM64_SME_FA64,
+ .sys_reg = SYS_ID_AA64SMFR0_EL1,
+ .sign = FTR_UNSIGNED,
+ .field_pos = ID_AA64SMFR0_FA64_SHIFT,
+ .min_field_value = ID_AA64SMFR0_FA64,
+ .matches = has_feature_flag,
+ .cpu_enable = fa64_kernel_enable,
+ },
+#endif /* CONFIG_ARM64_SME */
{},
};
@@ -2502,6 +2547,16 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_MTE_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_MTE, CAP_HWCAP, KERNEL_HWCAP_MTE),
#endif /* CONFIG_ARM64_MTE */
HWCAP_CAP(SYS_ID_AA64MMFR0_EL1, ID_AA64MMFR0_ECV_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_ECV),
+#ifdef CONFIG_ARM64_SME
+ HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_SME_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_SME, CAP_HWCAP, KERNEL_HWCAP_SME),
+ HWCAP_CAP_FLAG(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_FA64_SHIFT, CAP_HWCAP, KERNEL_HWCAP_SME_FA64),
+ HWCAP_CAP(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_I16I64_SHIFT, FTR_UNSIGNED, ID_AA64SMFR0_I16I64, CAP_HWCAP, KERNEL_HWCAP_SME_I16I64),
+ HWCAP_CAP_FLAG(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_F64F64_SHIFT, CAP_HWCAP, KERNEL_HWCAP_SME_F64F64),
+ HWCAP_CAP(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_I8I32_SHIFT, FTR_UNSIGNED, ID_AA64SMFR0_I8I32, CAP_HWCAP, KERNEL_HWCAP_SME_I8I32),
+ HWCAP_CAP_FLAG(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_F16F32_SHIFT, CAP_HWCAP, KERNEL_HWCAP_SME_F16F32),
+ HWCAP_CAP_FLAG(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_B16F32_SHIFT, CAP_HWCAP, KERNEL_HWCAP_SME_B16F32),
+ HWCAP_CAP_FLAG(SYS_ID_AA64SMFR0_EL1, ID_AA64SMFR0_F32F32_SHIFT, CAP_HWCAP, KERNEL_HWCAP_SME_F32F32),
+#endif /* CONFIG_ARM64_SME */
{},
};
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 6e27b759056a..5b0e9d2643a8 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -95,6 +95,14 @@ static const char *const hwcap_str[] = {
[KERNEL_HWCAP_BTI] = "bti",
[KERNEL_HWCAP_MTE] = "mte",
[KERNEL_HWCAP_ECV] = "ecv",
+ [KERNEL_HWCAP_SME] = "sme",
+ [KERNEL_HWCAP_SME_I16I64] = "smei16i64",
+ [KERNEL_HWCAP_SME_F64F64] = "smef64f64",
+ [KERNEL_HWCAP_SME_I8I32] = "smei8i32",
+ [KERNEL_HWCAP_SME_F16F32] = "smef16f32",
+ [KERNEL_HWCAP_SME_B16F32] = "smeb16f32",
+ [KERNEL_HWCAP_SME_F32F32] = "smef32f32",
+ [KERNEL_HWCAP_SME_FA64] = "smefa64",
};
#ifdef CONFIG_COMPAT
@@ -397,6 +405,7 @@ static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info)
info->reg_id_aa64pfr0 = read_cpuid(ID_AA64PFR0_EL1);
info->reg_id_aa64pfr1 = read_cpuid(ID_AA64PFR1_EL1);
info->reg_id_aa64zfr0 = read_cpuid(ID_AA64ZFR0_EL1);
+ info->reg_id_aa64smfr0 = read_cpuid(ID_AA64SMFR0_EL1);
if (id_aa64pfr1_mte(info->reg_id_aa64pfr1))
info->reg_gmid = read_cpuid(GMID_EL1);
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 4a98cc3b1df1..8dde4593ca73 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -983,6 +983,32 @@ void fpsimd_release_task(struct task_struct *dead_task)
#endif /* CONFIG_ARM64_SVE */
+#ifdef CONFIG_ARM64_SME
+
+void sme_kernel_enable(const struct arm64_cpu_capabilities *__always_unused p)
+{
+ /* Set priority for all PEs to architecturally defined minimum */
+ write_sysreg_s(read_sysreg_s(SYS_SMPRI_EL1) & ~SMPRI_EL1_PRIORITY_MASK,
+ SYS_SMPRI_EL1);
+
+ /* Allow SME in kernel */
+ write_sysreg(read_sysreg(CPACR_EL1) | CPACR_EL1_SMEN_EL1EN, CPACR_EL1);
+ isb();
+}
+
+/*
+ * This must be called after sme_kernel_enable(), we rely on the
+ * feature table being sorted to ensure this.
+ */
+void fa64_kernel_enable(const struct arm64_cpu_capabilities *__always_unused p)
+{
+ /* Allow use of FA64 */
+ write_sysreg_s(read_sysreg_s(SYS_SMCR_EL1) | SMCR_ELx_FA64_MASK,
+ SYS_SMCR_EL1);
+}
+
+#endif /* CONFIG_ARM64_SVE */
+
/*
* Trapped SVE access
*
@@ -1525,6 +1551,10 @@ static int __init fpsimd_init(void)
if (!cpu_have_named_feature(ASIMD))
pr_notice("Advanced SIMD is not implemented\n");
+
+ if (cpu_have_named_feature(SME) && !cpu_have_named_feature(SVE))
+ pr_notice("SME is implemented but not SVE\n");
+
return sve_sysctl_init();
}
core_initcall(fpsimd_init);
diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
index 870c39537dd0..58dfc8547c64 100644
--- a/arch/arm64/tools/cpucaps
+++ b/arch/arm64/tools/cpucaps
@@ -41,6 +41,8 @@ KVM_PROTECTED_MODE
MISMATCHED_CACHE_TYPE
MTE
MTE_ASYMM
+SME
+SME_FA64
SPECTRE_V2
SPECTRE_V3A
SPECTRE_V4
--
2.30.2
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