diff --git a/tools/include/asm/alternative.h b/tools/include/asm/alternative.h
index 7ce02a223732..8e548ac8f740 100644
--- a/tools/include/asm/alternative.h
+++ b/tools/include/asm/alternative.h
@@ -2,8 +2,18 @@
 #ifndef _TOOLS_ASM_ALTERNATIVE_ASM_H
 #define _TOOLS_ASM_ALTERNATIVE_ASM_H
 
+#if defined(__s390x__)
+#ifdef __ASSEMBLY__
+.macro ALTERNATIVE oldinstr, newinstr, feature
+	\oldinstr
+.endm
+#endif
+#else
+
 /* Just disable it so we can build arch/x86/lib/memcpy_64.S for perf bench: */
 
 #define ALTERNATIVE #
 
 #endif
+
+#endif
diff --git a/tools/testing/selftests/vDSO/vdso_test_chacha.c b/tools/testing/selftests/vDSO/vdso_test_chacha.c
index e81d72c9882e..b1ea532c5996 100644
--- a/tools/testing/selftests/vDSO/vdso_test_chacha.c
+++ b/tools/testing/selftests/vDSO/vdso_test_chacha.c
@@ -5,11 +5,29 @@
 
 #include <tools/le_byteshift.h>
 #include <sys/random.h>
+#include <sys/auxv.h>
 #include <string.h>
 #include <stdint.h>
 #include <stdbool.h>
 #include "../kselftest.h"
 
+#if defined(__aarch64__)
+static bool cpu_has_capabilities(void)
+{
+	return getauxval(AT_HWCAP) & HWCAP_ASIMD;
+}
+#elif defined(__s390x__)
+static bool cpu_has_capabilities(void)
+{
+	return getauxval(AT_HWCAP) & HWCAP_S390_VXRS;
+}
+#else
+static bool cpu_has_capabilities(void)
+{
+	return true;
+}
+#endif
+
 static uint32_t rol32(uint32_t word, unsigned int shift)
 {
 	return (word << (shift & 31)) | (word >> ((-shift) & 31));
@@ -67,6 +85,8 @@ int main(int argc, char *argv[])
 	uint8_t output1[BLOCK_SIZE * BLOCKS], output2[BLOCK_SIZE * BLOCKS];
 
 	ksft_print_header();
+	if (!cpu_has_capabilities())
+		ksft_exit_skip("Required CPU capabilities missing\n");
 	ksft_set_plan(1);
 
 	for (unsigned int trial = 0; trial < TRIALS; ++trial) {