1 files changed, 70 insertions, 0 deletions
diff --git a/tools/testing/selftests/powerpc/dscr/dscr_explicit_test.c b/tools/testing/selftests/powerpc/dscr/dscr_explicit_test.c
new file mode 100644
index 000000000..32fcf2b32
--- /dev/null
+++ b/tools/testing/selftests/powerpc/dscr/dscr_explicit_test.c
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * POWER Data Stream Control Register (DSCR) explicit test
+ *
+ * This test modifies the DSCR value using mtspr instruction and
+ * verifies the change with mfspr instruction. It uses both the
+ * privilege state SPR and the problem state SPR for this purpose.
+ *
+ * When using the privilege state SPR, the instructions such as
+ * mfspr or mtspr are priviledged and the kernel emulates them
+ * for us. Instructions using problem state SPR can be exuecuted
+ * directly without any emulation if the HW supports them. Else
+ * they also get emulated by the kernel.
+ *
+ * Copyright 2012, Anton Blanchard, IBM Corporation.
+ * Copyright 2015, Anshuman Khandual, IBM Corporation.
+ */
+#include "dscr.h"
+
+int dscr_explicit(void)
+{
+	unsigned long i, dscr = 0;
+
+	SKIP_IF(!have_hwcap2(PPC_FEATURE2_DSCR));
+
+	srand(getpid());
+	set_dscr(dscr);
+
+	for (i = 0; i < COUNT; i++) {
+		unsigned long cur_dscr, cur_dscr_usr;
+		double ret = uniform_deviate(rand());
+
+		if (ret < 0.001) {
+			dscr++;
+			if (dscr > DSCR_MAX)
+				dscr = 0;
+
+			set_dscr(dscr);
+		}
+
+		cur_dscr = get_dscr();
+		if (cur_dscr != dscr) {
+			fprintf(stderr, "Kernel DSCR should be %ld but "
+					"is %ld\n", dscr, cur_dscr);
+			return 1;
+		}
+
+		ret = uniform_deviate(rand());
+		if (ret < 0.001) {
+			dscr++;
+			if (dscr > DSCR_MAX)
+				dscr = 0;
+
+			set_dscr_usr(dscr);
+		}
+
+		cur_dscr_usr = get_dscr_usr();
+		if (cur_dscr_usr != dscr) {
+			fprintf(stderr, "User DSCR should be %ld but "
+					"is %ld\n", dscr, cur_dscr_usr);
+			return 1;
+		}
+	}
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	return test_harness(dscr_explicit, "dscr_explicit_test");
+}