@@ -64,6 +64,9 @@ struct cpuinfo_arm64 {
/* pseudo-ZCR for recording maximum ZCR_EL1 LEN value: */
u64 reg_zcr;
+
+ /* pseudo-SMCR for recording maximum SMCR_EL1 LEN value: */
+ u64 reg_smcr;
};
DECLARE_PER_CPU(struct cpuinfo_arm64, cpu_data);
@@ -622,6 +622,13 @@ static inline bool id_aa64pfr0_sve(u64 pfr0)
return val > 0;
}
+static inline bool id_aa64pfr1_sme(u64 pfr1)
+{
+ u32 val = cpuid_feature_extract_unsigned_field(pfr1, ID_AA64PFR1_SME_SHIFT);
+
+ return val > 0;
+}
+
static inline bool id_aa64pfr1_mte(u64 pfr1)
{
u32 val = cpuid_feature_extract_unsigned_field(pfr1, ID_AA64PFR1_MTE_SHIFT);
@@ -78,6 +78,7 @@ 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);
+extern u64 read_smcr_features(void);
/*
* Helpers to translate bit indices in sve_vq_map to VQ values (and
@@ -172,6 +173,12 @@ static inline void write_vl(enum vec_type type, u64 val)
tmp = read_sysreg_s(SYS_ZCR_EL1) & ~ZCR_ELx_LEN_MASK;
write_sysreg_s(tmp | val, SYS_ZCR_EL1);
break;
+#endif
+#ifdef CONFIG_ARM64_SME
+ case ARM64_VEC_SME:
+ tmp = read_sysreg_s(SYS_SMCR_EL1) & ~SMCR_ELx_LEN_MASK;
+ write_sysreg_s(tmp | val, SYS_SMCR_EL1);
+ break;
#endif
default:
WARN_ON_ONCE(1);
@@ -268,12 +275,31 @@ static inline void sme_smstop(void)
asm volatile(__msr_s(SYS_SVCR_SMSTOP_SMZA_EL0, "xzr"));
}
+extern void __init sme_setup(void);
+
+static inline int sme_max_vl(void)
+{
+ return vec_max_vl(ARM64_VEC_SME);
+}
+
+static inline int sme_max_virtualisable_vl(void)
+{
+ return vec_max_virtualisable_vl(ARM64_VEC_SME);
+}
+
+extern unsigned int sme_get_vl(void);
+
#else
static inline void sme_smstart_sm(void) { }
static inline void sme_smstop_sm(void) { }
static inline void sme_smstop(void) { }
+static inline void sme_setup(void) { }
+static inline unsigned int sme_get_vl(void) { return 0; }
+static inline int sme_max_vl(void) { return 0; }
+static inline int sme_max_virtualisable_vl(void) { return 0; }
+
#endif /* ! CONFIG_ARM64_SME */
/* For use by EFI runtime services calls only */
@@ -118,6 +118,7 @@ struct debug_info {
enum vec_type {
ARM64_VEC_SVE = 0,
+ ARM64_VEC_SME,
ARM64_VEC_MAX,
};
@@ -581,6 +581,12 @@ static const struct arm64_ftr_bits ftr_zcr[] = {
ARM64_FTR_END,
};
+static const struct arm64_ftr_bits ftr_smcr[] = {
+ ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE,
+ SMCR_ELx_LEN_SHIFT, SMCR_ELx_LEN_SIZE, 0), /* LEN */
+ ARM64_FTR_END,
+};
+
/*
* Common ftr bits for a 32bit register with all hidden, strict
* attributes, with 4bit feature fields and a default safe value of
@@ -687,6 +693,7 @@ static const struct __ftr_reg_entry {
/* Op1 = 0, CRn = 1, CRm = 2 */
ARM64_FTR_REG(SYS_ZCR_EL1, ftr_zcr),
+ ARM64_FTR_REG(SYS_SMCR_EL1, ftr_smcr),
/* Op1 = 1, CRn = 0, CRm = 0 */
ARM64_FTR_REG(SYS_GMID_EL1, ftr_gmid),
@@ -991,6 +998,12 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
vec_init_vq_map(ARM64_VEC_SVE);
}
+ if (id_aa64pfr1_sme(info->reg_id_aa64pfr1)) {
+ init_cpu_ftr_reg(SYS_SMCR_EL1, info->reg_smcr);
+ if (IS_ENABLED(CONFIG_ARM64_SME))
+ vec_init_vq_map(ARM64_VEC_SME);
+ }
+
if (id_aa64pfr1_mte(info->reg_id_aa64pfr1))
init_cpu_ftr_reg(SYS_GMID_EL1, info->reg_gmid);
@@ -1217,6 +1230,9 @@ void update_cpu_features(int cpu,
taint |= check_update_ftr_reg(SYS_ID_AA64ZFR0_EL1, cpu,
info->reg_id_aa64zfr0, boot->reg_id_aa64zfr0);
+ taint |= check_update_ftr_reg(SYS_ID_AA64SMFR0_EL1, cpu,
+ info->reg_id_aa64smfr0, boot->reg_id_aa64smfr0);
+
if (id_aa64pfr0_sve(info->reg_id_aa64pfr0)) {
taint |= check_update_ftr_reg(SYS_ZCR_EL1, cpu,
info->reg_zcr, boot->reg_zcr);
@@ -1227,6 +1243,16 @@ void update_cpu_features(int cpu,
vec_update_vq_map(ARM64_VEC_SVE);
}
+ if (id_aa64pfr1_sme(info->reg_id_aa64pfr1)) {
+ taint |= check_update_ftr_reg(SYS_SMCR_EL1, cpu,
+ info->reg_smcr, boot->reg_smcr);
+
+ /* Probe vector lengths, unless we already gave up on SME */
+ if (id_aa64pfr1_sme(read_sanitised_ftr_reg(SYS_ID_AA64PFR1_EL1)) &&
+ !system_capabilities_finalized())
+ vec_update_vq_map(ARM64_VEC_SME);
+ }
+
/*
* The kernel uses the LDGM/STGM instructions and the number of tags
* they read/write depends on the GMID_EL1.BS field. Check that the
@@ -2931,6 +2957,23 @@ static void verify_sve_features(void)
/* Add checks on other ZCR bits here if necessary */
}
+static void verify_sme_features(void)
+{
+ u64 safe_smcr = read_sanitised_ftr_reg(SYS_SMCR_EL1);
+ u64 smcr = read_smcr_features();
+
+ unsigned int safe_len = safe_smcr & SMCR_ELx_LEN_MASK;
+ unsigned int len = smcr & SMCR_ELx_LEN_MASK;
+
+ if (len < safe_len || vec_verify_vq_map(ARM64_VEC_SME)) {
+ pr_crit("CPU%d: SME: vector length support mismatch\n",
+ smp_processor_id());
+ cpu_die_early();
+ }
+
+ /* Add checks on other SMCR bits here if necessary */
+}
+
static void verify_hyp_capabilities(void)
{
u64 safe_mmfr1, mmfr0, mmfr1;
@@ -2983,6 +3026,9 @@ static void verify_local_cpu_capabilities(void)
if (system_supports_sve())
verify_sve_features();
+ if (system_supports_sme())
+ verify_sme_features();
+
if (is_hyp_mode_available())
verify_hyp_capabilities();
}
@@ -3100,6 +3146,7 @@ void __init setup_cpu_features(void)
pr_info("emulated: Privileged Access Never (PAN) using TTBR0_EL1 switching\n");
sve_setup();
+ sme_setup();
minsigstksz_setup();
/* Advertise that we have computed the system capabilities */
@@ -421,6 +421,10 @@ static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info)
id_aa64pfr0_sve(info->reg_id_aa64pfr0))
info->reg_zcr = read_zcr_features();
+ if (IS_ENABLED(CONFIG_ARM64_SME) &&
+ id_aa64pfr1_sme(info->reg_id_aa64pfr1))
+ info->reg_smcr = read_smcr_features();
+
cpuinfo_detect_icache_policy(info);
}
@@ -86,3 +86,12 @@ SYM_FUNC_START(sve_flush_live)
SYM_FUNC_END(sve_flush_live)
#endif /* CONFIG_ARM64_SVE */
+
+#ifdef CONFIG_ARM64_SME
+
+SYM_FUNC_START(sme_get_vl)
+ _sme_rdsvl 0, 1
+ ret
+SYM_FUNC_END(sme_get_vl)
+
+#endif /* CONFIG_ARM64_SME */
@@ -136,6 +136,12 @@ __ro_after_init struct vl_info vl_info[ARM64_VEC_MAX] = {
.max_virtualisable_vl = SVE_VL_MIN,
},
#endif
+#ifdef CONFIG_ARM64_SME
+ [ARM64_VEC_SME] = {
+ .type = ARM64_VEC_SME,
+ .name = "SME",
+ },
+#endif
};
static unsigned int vec_vl_inherit_flag(enum vec_type type)
@@ -186,6 +192,20 @@ extern void __percpu *efi_sve_state;
#endif /* ! CONFIG_ARM64_SVE */
+#ifdef CONFIG_ARM64_SME
+
+static int get_sme_default_vl(void)
+{
+ return get_default_vl(ARM64_VEC_SME);
+}
+
+static void set_sme_default_vl(int val)
+{
+ set_default_vl(ARM64_VEC_SME, val);
+}
+
+#endif
+
DEFINE_PER_CPU(bool, fpsimd_context_busy);
EXPORT_PER_CPU_SYMBOL(fpsimd_context_busy);
@@ -409,6 +429,8 @@ static unsigned int find_supported_vector_length(enum vec_type type,
if (vl > max_vl)
vl = max_vl;
+ if (vl < info->min_vl)
+ vl = info->min_vl;
bit = find_next_bit(info->vq_map, SVE_VQ_MAX,
__vq_to_bit(sve_vq_from_vl(vl)));
@@ -770,7 +792,23 @@ static void vec_probe_vqs(struct vl_info *info,
for (vq = SVE_VQ_MAX; vq >= SVE_VQ_MIN; --vq) {
write_vl(info->type, vq - 1); /* self-syncing */
- vl = sve_get_vl();
+
+ switch (info->type) {
+ case ARM64_VEC_SVE:
+ vl = sve_get_vl();
+ break;
+ case ARM64_VEC_SME:
+ vl = sme_get_vl();
+ break;
+ default:
+ vl = 0;
+ break;
+ }
+
+ /* Minimum VL identified? */
+ if (sve_vq_from_vl(vl) > vq)
+ break;
+
vq = sve_vq_from_vl(vl); /* skip intervening lengths */
set_bit(__vq_to_bit(vq), map);
}
@@ -1017,7 +1055,88 @@ void fa64_kernel_enable(const struct arm64_cpu_capabilities *__always_unused p)
SYS_SMCR_EL1);
}
-#endif /* CONFIG_ARM64_SVE */
+/*
+ * Read the pseudo-SMCR used by cpufeatures to identify the supported
+ * vector length.
+ *
+ * Use only if SME is present.
+ * This function clobbers the SME vector length.
+ */
+u64 read_smcr_features(void)
+{
+ u64 smcr;
+ unsigned int vq_max;
+
+ sme_kernel_enable(NULL);
+ sme_smstart_sm();
+
+ /*
+ * Set the maximum possible VL.
+ */
+ write_sysreg_s(read_sysreg_s(SYS_SMCR_EL1) | SMCR_ELx_LEN_MASK,
+ SYS_SMCR_EL1);
+
+ smcr = read_sysreg_s(SYS_SMCR_EL1);
+ smcr &= ~(u64)SMCR_ELx_LEN_MASK; /* Only the LEN field */
+ vq_max = sve_vq_from_vl(sve_get_vl());
+ smcr |= vq_max - 1; /* set LEN field to maximum effective value */
+
+ sme_smstop_sm();
+
+ return smcr;
+}
+
+void __init sme_setup(void)
+{
+ struct vl_info *info = &vl_info[ARM64_VEC_SME];
+ u64 smcr;
+ int min_bit;
+
+ if (!system_supports_sme())
+ return;
+
+ /*
+ * SME doesn't require any particular vector length be
+ * supported but it does require at least one. We should have
+ * disabled the feature entirely while bringing up CPUs but
+ * let's double check here.
+ */
+ WARN_ON(bitmap_empty(info->vq_map, SVE_VQ_MAX));
+
+ min_bit = find_last_bit(info->vq_map, SVE_VQ_MAX);
+ info->min_vl = sve_vl_from_vq(__bit_to_vq(min_bit));
+
+ smcr = read_sanitised_ftr_reg(SYS_SMCR_EL1);
+ info->max_vl = sve_vl_from_vq((smcr & SMCR_ELx_LEN_MASK) + 1);
+
+ /*
+ * Sanity-check that the max VL we determined through CPU features
+ * corresponds properly to sme_vq_map. If not, do our best:
+ */
+ if (WARN_ON(info->max_vl != find_supported_vector_length(ARM64_VEC_SME,
+ info->max_vl)))
+ info->max_vl = find_supported_vector_length(ARM64_VEC_SME,
+ info->max_vl);
+
+ WARN_ON(info->min_vl > info->max_vl);
+
+ /*
+ * For the default VL, pick the maximum supported value <= 32
+ * (256 bits) if there is one since this is guaranteed not to
+ * grow the signal frame when in streaming mode, otherwise the
+ * minimum available VL will be used.
+ */
+ set_sme_default_vl(find_supported_vector_length(ARM64_VEC_SME, 32));
+
+ pr_info("SME: minimum available vector length %u bytes per vector\n",
+ info->min_vl);
+ pr_info("SME: maximum available vector length %u bytes per vector\n",
+ info->max_vl);
+ pr_info("SME: default vector length %u bytes per vector\n",
+ get_sme_default_vl());
+}
+
+#endif /* CONFIG_ARM64_SME */
/*
* Trapped SVE access