72 lines
2.0 KiB
C
72 lines
2.0 KiB
C
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/utsname.h>
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#if defined(__linux__) && defined(HAVE_SYS_AUXV_H)
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# include <sys/auxv.h>
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#endif
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#include "zbuild.h"
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#include "riscv_features.h"
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#define ISA_V_HWCAP (1 << ('v' - 'a'))
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int Z_INTERNAL is_kernel_version_greater_or_equal_to_6_5() {
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struct utsname buffer;
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if (uname(&buffer) == -1) {
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// uname failed
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return 0;
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}
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int major, minor;
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if (sscanf(buffer.release, "%d.%d", &major, &minor) != 2) {
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// Something bad with uname()
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return 0;
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}
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if (major > 6 || (major == 6 && minor >= 5))
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return 1;
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return 0;
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}
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void Z_INTERNAL riscv_check_features_compile_time(struct riscv_cpu_features *features) {
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#if defined(__riscv_v) && defined(__linux__)
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features->has_rvv = 1;
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#else
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features->has_rvv = 0;
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#endif
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}
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void Z_INTERNAL riscv_check_features_runtime(struct riscv_cpu_features *features) {
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#if defined(__linux__) && defined(HAVE_SYS_AUXV_H)
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unsigned long hw_cap = getauxval(AT_HWCAP);
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#else
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unsigned long hw_cap = 0;
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#endif
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features->has_rvv = hw_cap & ISA_V_HWCAP;
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}
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void Z_INTERNAL riscv_check_features(struct riscv_cpu_features *features) {
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if (is_kernel_version_greater_or_equal_to_6_5())
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riscv_check_features_runtime(features);
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else
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riscv_check_features_compile_time(features);
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if (features->has_rvv) {
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size_t e8m1_vec_len;
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intptr_t vtype_reg_val;
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// Check that a vuint8m1_t vector is at least 16 bytes and that tail
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// agnostic and mask agnostic mode are supported
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//
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__asm__ volatile(
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"vsetvli %0, zero, e8, m1, ta, ma\n\t"
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"csrr %1, vtype"
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: "=r"(e8m1_vec_len), "=r"(vtype_reg_val));
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// The RVV target is supported if the VILL bit of VTYPE (the MSB bit of
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// VTYPE) is not set and the length of a vuint8m1_t vector is at least 16
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// bytes
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features->has_rvv = (vtype_reg_val >= 0 && e8m1_vec_len >= 16);
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}
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}
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