diff --git a/tools/testing/selftests/kselftest.h b/tools/testing/selftests/kselftest.h
index b8f248018174da83af52064af72eea51e52abe77..33a0dbd26bd342c4159df46de49177c5ef66e068 100644
--- a/tools/testing/selftests/kselftest.h
+++ b/tools/testing/selftests/kselftest.h
@@ -53,6 +53,21 @@
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
 #endif
 
+/*
+ * gcc cpuid.h provides __cpuid_count() since v4.4.
+ * Clang/LLVM cpuid.h provides  __cpuid_count() since v3.4.0.
+ *
+ * Provide local define for tests needing __cpuid_count() because
+ * selftests need to work in older environments that do not yet
+ * have __cpuid_count().
+ */
+#ifndef __cpuid_count
+#define __cpuid_count(level, count, a, b, c, d)				\
+	__asm__ __volatile__ ("cpuid\n\t"				\
+			      : "=a" (a), "=b" (b), "=c" (c), "=d" (d)	\
+			      : "0" (level), "2" (count))
+#endif
+
 /* define kselftest exit codes */
 #define KSFT_PASS  0
 #define KSFT_FAIL  1