arm64/sme: Add basic enumeration for SME2

Add basic feature detection for SME2, detecting that the feature is present
and disabling traps for ZT0.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20221208-arm64-sme2-v4-8-f2fa0aef982f@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 03d1c9d7af8216d3bfd62d698fc754b76c887c88..fc2c739f48f104c8b6a659f3722d1e9704a11cb6 100644 (file)
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -769,6 +769,12 @@ static __always_inline bool system_supports_sme(void)
                cpus_have_const_cap(ARM64_SME);
 }
 
+static __always_inline bool system_supports_sme2(void)
+{
+       return IS_ENABLED(CONFIG_ARM64_SME) &&
+               cpus_have_const_cap(ARM64_SME2);
+}
+
 static __always_inline bool system_supports_fa64(void)
 {
        return IS_ENABLED(CONFIG_ARM64_SME) &&

diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h
index 2d3fa80cd95db45cf8b136ac23d3eaf9ca02272e..2a66e3b94553bd99e12f1efd2d6b5968ea13de46 100644 (file)
--- a/arch/arm64/include/asm/fpsimd.h
+++ b/arch/arm64/include/asm/fpsimd.h
@@ -118,6 +118,7 @@ extern void za_load_state(void const *state);
 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 sme2_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/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index a77315b338e6113c4525ce8a24bae485ea869541..fd90905bc2e60d48240fcbae557710eb452200cc 100644 (file)
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -282,6 +282,8 @@ static const struct arm64_ftr_bits ftr_id_aa64zfr0[] = {
 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_EL1_FA64_SHIFT, 1, 0),
+       ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+                      FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_SMEver_SHIFT, 4, 0),
        ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
                       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_I16I64_SHIFT, 4, 0),
        ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
@@ -2649,6 +2651,18 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
                .matches = has_cpuid_feature,
                .cpu_enable = fa64_kernel_enable,
        },
+       {
+               .desc = "SME2",
+               .type = ARM64_CPUCAP_SYSTEM_FEATURE,
+               .capability = ARM64_SME2,
+               .sys_reg = SYS_ID_AA64PFR1_EL1,
+               .sign = FTR_UNSIGNED,
+               .field_pos = ID_AA64PFR1_EL1_SME_SHIFT,
+               .field_width = ID_AA64PFR1_EL1_SME_WIDTH,
+               .min_field_value = ID_AA64PFR1_EL1_SME_SME2,
+               .matches = has_cpuid_feature,
+               .cpu_enable = sme2_kernel_enable,
+       },
 #endif /* CONFIG_ARM64_SME */
        {
                .desc = "WFx with timeout",

diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 9e168a9eb615692b3ce2952d74d01139465fe7f5..717ae4aaa0218ccb72b3db35eba56ebb5f0a4678 100644 (file)
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -1298,6 +1298,17 @@ void sme_kernel_enable(const struct arm64_cpu_capabilities *__always_unused p)
        isb();
 }
 
+/*
+ * This must be called after sme_kernel_enable(), we rely on the
+ * feature table being sorted to ensure this.
+ */
+void sme2_kernel_enable(const struct arm64_cpu_capabilities *__always_unused p)
+{
+       /* Allow use of ZT0 */
+       write_sysreg_s(read_sysreg_s(SYS_SMCR_EL1) | SMCR_ELx_EZT0_MASK,
+                      SYS_SMCR_EL1);
+}
+
 /*
  * This must be called after sme_kernel_enable(), we rely on the
  * feature table being sorted to ensure this.

diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
index a86ee376920a08ddfdb7f116336a90ed13e88629..1222b0ed63a231954e0d7651bc10c0e778be34ca 100644 (file)
--- a/arch/arm64/tools/cpucaps
+++ b/arch/arm64/tools/cpucaps
@@ -50,6 +50,7 @@ MTE
 MTE_ASYMM
 SME
 SME_FA64
+SME2
 SPECTRE_V2
 SPECTRE_V3A
 SPECTRE_V4