vendor: OpenCV 5.0.0 snapshot at 40738fb16ceddb5fb3fea747585f7ce6abb0605b

3rdparty/zlib-ng/arch/riscv/riscv_features.c

@@ -0,0 +1,52 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/utsname.h>
+
+#if defined(__linux__) && defined(HAVE_SYS_AUXV_H)
+#  include <sys/auxv.h>
+#endif
+
+#include "zbuild.h"
+#include "riscv_features.h"
+
+#define ISA_V_HWCAP (1 << ('v' - 'a'))
+
+int Z_INTERNAL is_kernel_version_greater_or_equal_to_6_5() {
+    struct utsname buffer;
+    uname(&buffer);
+
+    int major, minor;
+    if (sscanf(buffer.release, "%d.%d", &major, &minor) != 2) {
+        // Something bad with uname()
+        return 0;
+    }
+
+    if (major > 6 || major == 6 && minor >= 5)
+        return 1;
+    return 0;
+}
+
+void Z_INTERNAL riscv_check_features_compile_time(struct riscv_cpu_features *features) {
+#if defined(__riscv_v) && defined(__linux__)
+    features->has_rvv = 1;
+#else
+    features->has_rvv = 0;
+#endif
+}
+
+void Z_INTERNAL riscv_check_features_runtime(struct riscv_cpu_features *features) {
+#if defined(__linux__) && defined(HAVE_SYS_AUXV_H)
+    unsigned long hw_cap = getauxval(AT_HWCAP);
+#else
+    unsigned long hw_cap = 0;
+#endif
+    features->has_rvv = hw_cap & ISA_V_HWCAP;
+}
+
+void Z_INTERNAL riscv_check_features(struct riscv_cpu_features *features) {
+    if (is_kernel_version_greater_or_equal_to_6_5())
+        riscv_check_features_runtime(features);
+    else
+        riscv_check_features_compile_time(features);
+}