2 files changed, 27 insertions, 4 deletions
diff --git a/tools/testing/selftests/powerpc/math/fpu.h b/tools/testing/selftests/powerpc/math/fpu.h
new file mode 100644
index 000000000000..a8ad0d42604e
--- /dev/null
+++ b/tools/testing/selftests/powerpc/math/fpu.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright 2023, Michael Ellerman, IBM Corporation.
+ */
+
+#ifndef _SELFTESTS_POWERPC_FPU_H
+#define _SELFTESTS_POWERPC_FPU_H
+
+static inline void randomise_darray(double *darray, int num)
+{
+	long val;
+
+	for (int i = 0; i < num; i++) {
+		val = random();
+		if (val & 1)
+			val *= -1;
+
+		if (val & 2)
+			darray[i] = 1.0 / val;
+		else
+			darray[i] = val * val;
+	}
+}
+
+#endif /* _SELFTESTS_POWERPC_FPU_H */
diff --git a/tools/testing/selftests/powerpc/math/fpu_preempt.c b/tools/testing/selftests/powerpc/math/fpu_preempt.c
index 24b5abacccdc..97dff3690136 100644
--- a/tools/testing/selftests/powerpc/math/fpu_preempt.c
+++ b/tools/testing/selftests/powerpc/math/fpu_preempt.c
@@ -19,6 +19,7 @@
 #include <pthread.h>
 
 #include "utils.h"
+#include "fpu.h"
 
 /* Time to wait for workers to get preempted (seconds) */
 #define PREEMPT_TIME 20
@@ -39,12 +40,9 @@ extern int preempt_fpu(double *darray, int *threads_starting, int *running);
 void *preempt_fpu_c(void *p)
 {
 	long rc;
-	int i;
 
 	srand(pthread_self());
-	for (i = 0; i < ARRAY_SIZE(darray); i++)
-		darray[i] = rand();
-
+	randomise_darray(darray, ARRAY_SIZE(darray));
 	rc = preempt_fpu(darray, &threads_starting, &running);
 
 	return (void *)rc;