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-rw-r--r--arch/arm64/kernel/cpufeature.c52
-rw-r--r--arch/arm64/kernel/cpuinfo.c6
-rw-r--r--arch/arm64/kernel/fpsimd.c114
3 files changed, 169 insertions, 3 deletions
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 0e192cbe4149..036ad9d1b442 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -27,6 +27,7 @@
#include <asm/cpu.h>
#include <asm/cpufeature.h>
#include <asm/cpu_ops.h>
+#include <asm/fpsimd.h>
#include <asm/mmu_context.h>
#include <asm/processor.h>
#include <asm/sysreg.h>
@@ -287,6 +288,12 @@ static const struct arm64_ftr_bits ftr_id_dfr0[] = {
ARM64_FTR_END,
};
+static const struct arm64_ftr_bits ftr_zcr[] = {
+ ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE,
+ ZCR_ELx_LEN_SHIFT, ZCR_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
@@ -353,6 +360,7 @@ static const struct __ftr_reg_entry {
/* Op1 = 0, CRn = 0, CRm = 4 */
ARM64_FTR_REG(SYS_ID_AA64PFR0_EL1, ftr_id_aa64pfr0),
ARM64_FTR_REG(SYS_ID_AA64PFR1_EL1, ftr_raz),
+ ARM64_FTR_REG(SYS_ID_AA64ZFR0_EL1, ftr_raz),
/* Op1 = 0, CRn = 0, CRm = 5 */
ARM64_FTR_REG(SYS_ID_AA64DFR0_EL1, ftr_id_aa64dfr0),
@@ -367,6 +375,9 @@ static const struct __ftr_reg_entry {
ARM64_FTR_REG(SYS_ID_AA64MMFR1_EL1, ftr_id_aa64mmfr1),
ARM64_FTR_REG(SYS_ID_AA64MMFR2_EL1, ftr_id_aa64mmfr2),
+ /* Op1 = 0, CRn = 1, CRm = 2 */
+ ARM64_FTR_REG(SYS_ZCR_EL1, ftr_zcr),
+
/* Op1 = 3, CRn = 0, CRm = 0 */
{ SYS_CTR_EL0, &arm64_ftr_reg_ctrel0 },
ARM64_FTR_REG(SYS_DCZID_EL0, ftr_dczid),
@@ -504,6 +515,7 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
init_cpu_ftr_reg(SYS_ID_AA64MMFR2_EL1, info->reg_id_aa64mmfr2);
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);
if (id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0)) {
init_cpu_ftr_reg(SYS_ID_DFR0_EL1, info->reg_id_dfr0);
@@ -524,6 +536,10 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
init_cpu_ftr_reg(SYS_MVFR2_EL1, info->reg_mvfr2);
}
+ if (id_aa64pfr0_sve(info->reg_id_aa64pfr0)) {
+ init_cpu_ftr_reg(SYS_ZCR_EL1, info->reg_zcr);
+ sve_init_vq_map();
+ }
}
static void update_cpu_ftr_reg(struct arm64_ftr_reg *reg, u64 new)
@@ -627,6 +643,9 @@ void update_cpu_features(int cpu,
taint |= check_update_ftr_reg(SYS_ID_AA64PFR1_EL1, cpu,
info->reg_id_aa64pfr1, boot->reg_id_aa64pfr1);
+ taint |= check_update_ftr_reg(SYS_ID_AA64ZFR0_EL1, cpu,
+ info->reg_id_aa64zfr0, boot->reg_id_aa64zfr0);
+
/*
* If we have AArch32, we care about 32-bit features for compat.
* If the system doesn't support AArch32, don't update them.
@@ -674,6 +693,16 @@ void update_cpu_features(int cpu,
info->reg_mvfr2, boot->reg_mvfr2);
}
+ if (id_aa64pfr0_sve(info->reg_id_aa64pfr0)) {
+ taint |= check_update_ftr_reg(SYS_ZCR_EL1, cpu,
+ info->reg_zcr, boot->reg_zcr);
+
+ /* Probe vector lengths, unless we already gave up on SVE */
+ if (id_aa64pfr0_sve(read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1)) &&
+ !sys_caps_initialised)
+ sve_update_vq_map();
+ }
+
/*
* Mismatched CPU features are a recipe for disaster. Don't even
* pretend to support them.
@@ -1106,6 +1135,23 @@ verify_local_cpu_features(const struct arm64_cpu_capabilities *caps)
}
}
+static void verify_sve_features(void)
+{
+ u64 safe_zcr = read_sanitised_ftr_reg(SYS_ZCR_EL1);
+ u64 zcr = read_zcr_features();
+
+ unsigned int safe_len = safe_zcr & ZCR_ELx_LEN_MASK;
+ unsigned int len = zcr & ZCR_ELx_LEN_MASK;
+
+ if (len < safe_len || sve_verify_vq_map()) {
+ pr_crit("CPU%d: SVE: required vector length(s) missing\n",
+ smp_processor_id());
+ cpu_die_early();
+ }
+
+ /* Add checks on other ZCR bits here if necessary */
+}
+
/*
* Run through the enabled system capabilities and enable() it on this CPU.
* The capabilities were decided based on the available CPUs at the boot time.
@@ -1119,8 +1165,12 @@ static void verify_local_cpu_capabilities(void)
verify_local_cpu_errata_workarounds();
verify_local_cpu_features(arm64_features);
verify_local_elf_hwcaps(arm64_elf_hwcaps);
+
if (system_supports_32bit_el0())
verify_local_elf_hwcaps(compat_elf_hwcaps);
+
+ if (system_supports_sve())
+ verify_sve_features();
}
void check_local_cpu_capabilities(void)
@@ -1198,6 +1248,8 @@ void __init setup_cpu_features(void)
if (system_supports_32bit_el0())
setup_elf_hwcaps(compat_elf_hwcaps);
+ sve_setup();
+
/* Advertise that we have computed the system capabilities */
set_sys_caps_initialised();
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 1ff1c5a67081..58da504be36e 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -19,6 +19,7 @@
#include <asm/cpu.h>
#include <asm/cputype.h>
#include <asm/cpufeature.h>
+#include <asm/fpsimd.h>
#include <linux/bitops.h>
#include <linux/bug.h>
@@ -331,6 +332,7 @@ static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info)
info->reg_id_aa64mmfr2 = read_cpuid(ID_AA64MMFR2_EL1);
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);
/* Update the 32bit ID registers only if AArch32 is implemented */
if (id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0)) {
@@ -353,6 +355,10 @@ static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info)
info->reg_mvfr2 = read_cpuid(MVFR2_EL1);
}
+ if (IS_ENABLED(CONFIG_ARM64_SVE) &&
+ id_aa64pfr0_sve(info->reg_id_aa64pfr0))
+ info->reg_zcr = read_zcr_features();
+
cpuinfo_detect_icache_policy(info);
}
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 667be3472114..715398e91d65 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -115,19 +115,19 @@
static DEFINE_PER_CPU(struct fpsimd_state *, fpsimd_last_state);
/* Default VL for tasks that don't set it explicitly: */
-static int sve_default_vl = SVE_VL_MIN;
+static int sve_default_vl = -1;
#ifdef CONFIG_ARM64_SVE
/* Maximum supported vector length across all CPUs (initially poisoned) */
int __ro_after_init sve_max_vl = -1;
/* Set of available vector lengths, as vq_to_bit(vq): */
-static DECLARE_BITMAP(sve_vq_map, SVE_VQ_MAX);
+static __ro_after_init DECLARE_BITMAP(sve_vq_map, SVE_VQ_MAX);
#else /* ! CONFIG_ARM64_SVE */
/* Dummy declaration for code that will be optimised out: */
-extern DECLARE_BITMAP(sve_vq_map, SVE_VQ_MAX);
+extern __ro_after_init DECLARE_BITMAP(sve_vq_map, SVE_VQ_MAX);
#endif /* ! CONFIG_ARM64_SVE */
@@ -497,6 +497,111 @@ out:
}
/*
+ * Bitmap for temporary storage of the per-CPU set of supported vector lengths
+ * during secondary boot.
+ */
+static DECLARE_BITMAP(sve_secondary_vq_map, SVE_VQ_MAX);
+
+static void sve_probe_vqs(DECLARE_BITMAP(map, SVE_VQ_MAX))
+{
+ unsigned int vq, vl;
+ unsigned long zcr;
+
+ bitmap_zero(map, SVE_VQ_MAX);
+
+ zcr = ZCR_ELx_LEN_MASK;
+ zcr = read_sysreg_s(SYS_ZCR_EL1) & ~zcr;
+
+ for (vq = SVE_VQ_MAX; vq >= SVE_VQ_MIN; --vq) {
+ write_sysreg_s(zcr | (vq - 1), SYS_ZCR_EL1); /* self-syncing */
+ vl = sve_get_vl();
+ vq = sve_vq_from_vl(vl); /* skip intervening lengths */
+ set_bit(vq_to_bit(vq), map);
+ }
+}
+
+void __init sve_init_vq_map(void)
+{
+ sve_probe_vqs(sve_vq_map);
+}
+
+/*
+ * If we haven't committed to the set of supported VQs yet, filter out
+ * those not supported by the current CPU.
+ */
+void sve_update_vq_map(void)
+{
+ sve_probe_vqs(sve_secondary_vq_map);
+ bitmap_and(sve_vq_map, sve_vq_map, sve_secondary_vq_map, SVE_VQ_MAX);
+}
+
+/* Check whether the current CPU supports all VQs in the committed set */
+int sve_verify_vq_map(void)
+{
+ int ret = 0;
+
+ sve_probe_vqs(sve_secondary_vq_map);
+ bitmap_andnot(sve_secondary_vq_map, sve_vq_map, sve_secondary_vq_map,
+ SVE_VQ_MAX);
+ if (!bitmap_empty(sve_secondary_vq_map, SVE_VQ_MAX)) {
+ pr_warn("SVE: cpu%d: Required vector length(s) missing\n",
+ smp_processor_id());
+ ret = -EINVAL;
+ }
+
+ return ret;
+}
+
+/*
+ * Enable SVE for EL1.
+ * Intended for use by the cpufeatures code during CPU boot.
+ */
+int sve_kernel_enable(void *__always_unused p)
+{
+ write_sysreg(read_sysreg(CPACR_EL1) | CPACR_EL1_ZEN_EL1EN, CPACR_EL1);
+ isb();
+
+ return 0;
+}
+
+void __init sve_setup(void)
+{
+ u64 zcr;
+
+ if (!system_supports_sve())
+ return;
+
+ /*
+ * The SVE architecture mandates support for 128-bit vectors,
+ * so sve_vq_map must have at least SVE_VQ_MIN set.
+ * If something went wrong, at least try to patch it up:
+ */
+ if (WARN_ON(!test_bit(vq_to_bit(SVE_VQ_MIN), sve_vq_map)))
+ set_bit(vq_to_bit(SVE_VQ_MIN), sve_vq_map);
+
+ zcr = read_sanitised_ftr_reg(SYS_ZCR_EL1);
+ sve_max_vl = sve_vl_from_vq((zcr & ZCR_ELx_LEN_MASK) + 1);
+
+ /*
+ * Sanity-check that the max VL we determined through CPU features
+ * corresponds properly to sve_vq_map. If not, do our best:
+ */
+ if (WARN_ON(sve_max_vl != find_supported_vector_length(sve_max_vl)))
+ sve_max_vl = find_supported_vector_length(sve_max_vl);
+
+ /*
+ * For the default VL, pick the maximum supported value <= 64.
+ * VL == 64 is guaranteed not to grow the signal frame.
+ */
+ sve_default_vl = find_supported_vector_length(64);
+
+ pr_info("SVE: maximum available vector length %u bytes per vector\n",
+ sve_max_vl);
+ pr_info("SVE: default vector length %u bytes per vector\n",
+ sve_default_vl);
+}
+
+/*
* Called from the put_task_struct() path, which cannot get here
* unless dead_task is really dead and not schedulable.
*/
@@ -631,6 +736,9 @@ void fpsimd_flush_thread(void)
* This is where we ensure that all user tasks have a valid
* vector length configured: no kernel task can become a user
* task without an exec and hence a call to this function.
+ * By the time the first call to this function is made, all
+ * early hardware probing is complete, so sve_default_vl
+ * should be valid.
* If a bug causes this to go wrong, we make some noise and
* try to fudge thread.sve_vl to a safe value here.
*/
generated by cgit (git 2.34.1) at 2024-05-22 14:00:50 +0000