1 files changed, 127 insertions, 0 deletions
diff --git a/tools/testing/selftests/powerpc/dscr/dscr_default_test.c b/tools/testing/selftests/powerpc/dscr/dscr_default_test.c
new file mode 100644
index 000000000..9e1a37e93
--- /dev/null
+++ b/tools/testing/selftests/powerpc/dscr/dscr_default_test.c
@@ -0,0 +1,127 @@
+/*
+ * POWER Data Stream Control Register (DSCR) default test
+ *
+ * This test modifies the system wide default DSCR through
+ * it's sysfs interface and then verifies that all threads
+ * see the correct changed DSCR value immediately.
+ *
+ * Copyright 2012, Anton Blanchard, IBM Corporation.
+ * Copyright 2015, Anshuman Khandual, IBM Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+#include "dscr.h"
+
+static unsigned long dscr;		/* System DSCR default */
+static unsigned long sequence;
+static unsigned long result[THREADS];
+
+static void *do_test(void *in)
+{
+	unsigned long thread = (unsigned long)in;
+	unsigned long i;
+
+	for (i = 0; i < COUNT; i++) {
+		unsigned long d, cur_dscr, cur_dscr_usr;
+		unsigned long s1, s2;
+
+		s1 = READ_ONCE(sequence);
+		if (s1 & 1)
+			continue;
+		rmb();
+
+		d = dscr;
+		cur_dscr = get_dscr();
+		cur_dscr_usr = get_dscr_usr();
+
+		rmb();
+		s2 = sequence;
+
+		if (s1 != s2)
+			continue;
+
+		if (cur_dscr != d) {
+			fprintf(stderr, "thread %ld kernel DSCR should be %ld "
+				"but is %ld\n", thread, d, cur_dscr);
+			result[thread] = 1;
+			pthread_exit(&result[thread]);
+		}
+
+		if (cur_dscr_usr != d) {
+			fprintf(stderr, "thread %ld user DSCR should be %ld "
+				"but is %ld\n", thread, d, cur_dscr_usr);
+			result[thread] = 1;
+			pthread_exit(&result[thread]);
+		}
+	}
+	result[thread] = 0;
+	pthread_exit(&result[thread]);
+}
+
+int dscr_default(void)
+{
+	pthread_t threads[THREADS];
+	unsigned long i, *status[THREADS];
+	unsigned long orig_dscr_default;
+
+	orig_dscr_default = get_default_dscr();
+
+	/* Initial DSCR default */
+	dscr = 1;
+	set_default_dscr(dscr);
+
+	/* Spawn all testing threads */
+	for (i = 0; i < THREADS; i++) {
+		if (pthread_create(&threads[i], NULL, do_test, (void *)i)) {
+			perror("pthread_create() failed");
+			goto fail;
+		}
+	}
+
+	srand(getpid());
+
+	/* Keep changing the DSCR default */
+	for (i = 0; i < COUNT; i++) {
+		double ret = uniform_deviate(rand());
+
+		if (ret < 0.0001) {
+			sequence++;
+			wmb();
+
+			dscr++;
+			if (dscr > DSCR_MAX)
+				dscr = 0;
+
+			set_default_dscr(dscr);
+
+			wmb();
+			sequence++;
+		}
+	}
+
+	/* Individual testing thread exit status */
+	for (i = 0; i < THREADS; i++) {
+		if (pthread_join(threads[i], (void **)&(status[i]))) {
+			perror("pthread_join() failed");
+			goto fail;
+		}
+
+		if (*status[i]) {
+			printf("%ldth thread failed to join with %ld status\n",
+								i, *status[i]);
+			goto fail;
+		}
+	}
+	set_default_dscr(orig_dscr_default);
+	return 0;
+fail:
+	set_default_dscr(orig_dscr_default);
+	return 1;
+}
+
+int main(int argc, char *argv[])
+{
+	return test_harness(dscr_default, "dscr_default_test");
+}