Implement getcpu syscall and add corresponding test application

test/apps/getcpu/getcpu.c

@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: MPL-2.0
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+
+int main()
+{
+	unsigned int cpu, node;
+
+	// Directly test the getcpu syscall because glibc's getcpu() may not
+	// use the getcpu syscall to retrieve CPU info
+	long ret = syscall(SYS_getcpu, &cpu, &node, NULL);
+	if (ret != 0) {
+		perror("syscall getcpu");
+		exit(EXIT_FAILURE);
+	}
+
+	printf("getcpu syscall: cpu = %u, node = %u\n", cpu, node);
+
+	return 0;
+}