1 files changed, 136 insertions, 33 deletions

diff --git a/tools/testing/selftests/powerpc/dscr/dscr_explicit_test.c b/tools/testing/selftests/powerpc/dscr/dscr_explicit_test.c
index 32fcf2b324b1..e2268e9183a8 100644
--- a/tools/testing/selftests/powerpc/dscr/dscr_explicit_test.c
+++ b/tools/testing/selftests/powerpc/dscr/dscr_explicit_test.c
@@ -7,64 +7,167 @@
  * 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
+ * mfspr or mtspr are privileged and the kernel emulates them
+ * for us. Instructions using problem state SPR can be executed
  * 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.
  */
+
+#define _GNU_SOURCE
+
 #include "dscr.h"
+#include "utils.h"
+
+#include <pthread.h>
+#include <sched.h>
+#include <semaphore.h>
 
-int dscr_explicit(void)
+void *dscr_explicit_lockstep_thread(void *args)
 {
-	unsigned long i, dscr = 0;
+	sem_t *prev = (sem_t *)args;
+	sem_t *next = (sem_t *)args + 1;
+	unsigned long expected_dscr = 0;
+
+	set_dscr(expected_dscr);
+	srand(gettid());
+
+	for (int i = 0; i < COUNT; i++) {
+		FAIL_IF_EXIT(sem_wait(prev));
+
+		FAIL_IF_EXIT(expected_dscr != get_dscr());
+		FAIL_IF_EXIT(expected_dscr != get_dscr_usr());
+
+		expected_dscr = (expected_dscr + 1) % DSCR_MAX;
+		set_dscr(expected_dscr);
+
+		FAIL_IF_EXIT(sem_post(next));
+	}
+
+	return NULL;
+}
+
+int dscr_explicit_lockstep_test(void)
+{
+	pthread_t thread;
+	sem_t semaphores[2];
+	sem_t *prev = &semaphores[1];  /* reversed prev/next than for the other thread */
+	sem_t *next = &semaphores[0];
+	unsigned long expected_dscr = 0;
 
 	SKIP_IF(!have_hwcap2(PPC_FEATURE2_DSCR));
 
-	srand(getpid());
-	set_dscr(dscr);
+	srand(gettid());
+	set_dscr(expected_dscr);
 
-	for (i = 0; i < COUNT; i++) {
-		unsigned long cur_dscr, cur_dscr_usr;
-		double ret = uniform_deviate(rand());
+	FAIL_IF(sem_init(prev, 0, 0));
+	FAIL_IF(sem_init(next, 0, 1));  /* other thread starts first */
+	FAIL_IF(bind_to_cpu(BIND_CPU_ANY) < 0);
+	FAIL_IF(pthread_create(&thread, NULL, dscr_explicit_lockstep_thread, (void *)semaphores));
 
-		if (ret < 0.001) {
-			dscr++;
-			if (dscr > DSCR_MAX)
-				dscr = 0;
+	for (int i = 0; i < COUNT; i++) {
+		FAIL_IF(sem_wait(prev));
 
-			set_dscr(dscr);
-		}
+		FAIL_IF(expected_dscr != get_dscr());
+		FAIL_IF(expected_dscr != get_dscr_usr());
 
-		cur_dscr = get_dscr();
-		if (cur_dscr != dscr) {
-			fprintf(stderr, "Kernel DSCR should be %ld but "
-					"is %ld\n", dscr, cur_dscr);
-			return 1;
-		}
+		expected_dscr = (expected_dscr - 1) % DSCR_MAX;
+		set_dscr(expected_dscr);
+
+		FAIL_IF(sem_post(next));
+	}
+
+	FAIL_IF(pthread_join(thread, NULL));
+	FAIL_IF(sem_destroy(prev));
+	FAIL_IF(sem_destroy(next));
+
+	return 0;
+}
+
+struct random_thread_args {
+	pthread_t thread_id;
+	bool do_yields;
+	pthread_barrier_t *barrier;
+};
+
+void *dscr_explicit_random_thread(void *in)
+{
+	struct random_thread_args *args = (struct random_thread_args *)in;
+	unsigned long expected_dscr = 0;
+	int err;
+
+	srand(gettid());
+
+	err = pthread_barrier_wait(args->barrier);
+	FAIL_IF_EXIT(err != 0 && err != PTHREAD_BARRIER_SERIAL_THREAD);
 
-		ret = uniform_deviate(rand());
-		if (ret < 0.001) {
-			dscr++;
-			if (dscr > DSCR_MAX)
-				dscr = 0;
+	for (int i = 0; i < COUNT; i++) {
+		expected_dscr = rand() % DSCR_MAX;
+		set_dscr(expected_dscr);
 
-			set_dscr_usr(dscr);
+		for (int j = rand() % 5; j > 0; --j) {
+			FAIL_IF_EXIT(get_dscr() != expected_dscr);
+			FAIL_IF_EXIT(get_dscr_usr() != expected_dscr);
+
+			if (args->do_yields && rand() % 2)
+				sched_yield();
 		}
 
-		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;
+		expected_dscr = rand() % DSCR_MAX;
+		set_dscr_usr(expected_dscr);
+
+		for (int j = rand() % 5; j > 0; --j) {
+			FAIL_IF_EXIT(get_dscr() != expected_dscr);
+			FAIL_IF_EXIT(get_dscr_usr() != expected_dscr);
+
+			if (args->do_yields && rand() % 2)
+				sched_yield();
 		}
 	}
+
+	return NULL;
+}
+
+int dscr_explicit_random_test(void)
+{
+	struct random_thread_args threads[THREADS];
+	pthread_barrier_t barrier;
+
+	SKIP_IF(!have_hwcap2(PPC_FEATURE2_DSCR));
+
+	FAIL_IF(pthread_barrier_init(&barrier, NULL, THREADS));
+
+	for (int i = 0; i < THREADS; i++) {
+		threads[i].do_yields = i % 2 == 0;
+		threads[i].barrier = &barrier;
+
+		FAIL_IF(pthread_create(&threads[i].thread_id, NULL,
+				       dscr_explicit_random_thread, (void *)&threads[i]));
+	}
+
+	for (int i = 0; i < THREADS; i++)
+		FAIL_IF(pthread_join(threads[i].thread_id, NULL));
+
+	FAIL_IF(pthread_barrier_destroy(&barrier));
+
 	return 0;
 }
 
 int main(int argc, char *argv[])
 {
-	return test_harness(dscr_explicit, "dscr_explicit_test");
+	unsigned long orig_dscr_default = 0;
+	int err = 0;
+
+	if (have_hwcap2(PPC_FEATURE2_DSCR))
+		orig_dscr_default = get_default_dscr();
+
+	err |= test_harness(dscr_explicit_lockstep_test, "dscr_explicit_lockstep_test");
+	err |= test_harness(dscr_explicit_random_test, "dscr_explicit_random_test");
+
+	if (have_hwcap2(PPC_FEATURE2_DSCR))
+		set_default_dscr(orig_dscr_default);
+
+	return err;
 }