1 files changed, 145 insertions, 0 deletions
diff --git a/tools/testing/selftests/powerpc/math/vsx_preempt.c b/tools/testing/selftests/powerpc/math/vsx_preempt.c
new file mode 100644
index 000000000..d1601bb88
--- /dev/null
+++ b/tools/testing/selftests/powerpc/math/vsx_preempt.c
@@ -0,0 +1,145 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2015, Cyril Bur, IBM Corp.
+ *
+ * This test attempts to see if the VSX registers change across preemption.
+ * There is no way to be sure preemption happened so this test just
+ * uses many threads and a long wait. As such, a successful test
+ * doesn't mean much but a failure is bad.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdlib.h>
+#include <pthread.h>
+
+#include "utils.h"
+
+/* Time to wait for workers to get preempted (seconds) */
+#define PREEMPT_TIME 20
+/*
+ * Factor by which to multiply number of online CPUs for total number of
+ * worker threads
+ */
+#define THREAD_FACTOR 8
+
+/*
+ * Ensure there is twice the number of non-volatile VMX regs!
+ * check_vmx() is going to use the other half as space to put the live
+ * registers before calling vsx_memcmp()
+ */
+__thread vector int varray[24] = {
+	{1, 2, 3, 4 }, {5, 6, 7, 8 }, {9, 10,11,12},
+	{13,14,15,16}, {17,18,19,20}, {21,22,23,24},
+	{25,26,27,28}, {29,30,31,32}, {33,34,35,36},
+	{37,38,39,40}, {41,42,43,44}, {45,46,47,48}
+};
+
+int threads_starting;
+int running;
+
+extern long preempt_vsx(vector int *varray, int *threads_starting, int *running);
+
+long vsx_memcmp(vector int *a) {
+	vector int zero = {0, 0, 0, 0};
+	int i;
+
+	FAIL_IF(a != varray);
+
+	for(i = 0; i < 12; i++) {
+		if (memcmp(&a[i + 12], &zero, sizeof(vector int)) == 0) {
+			fprintf(stderr, "Detected zero from the VSX reg %d\n", i + 12);
+			return 2;
+		}
+	}
+
+	if (memcmp(a, &a[12], 12 * sizeof(vector int))) {
+		long *p = (long *)a;
+		fprintf(stderr, "VSX mismatch\n");
+		for (i = 0; i < 24; i=i+2)
+			fprintf(stderr, "%d: 0x%08lx%08lx | 0x%08lx%08lx\n",
+					i/2 + i%2 + 20, p[i], p[i + 1], p[i + 24], p[i + 25]);
+		return 1;
+	}
+	return 0;
+}
+
+void *preempt_vsx_c(void *p)
+{
+	int i, j;
+	long rc;
+	srand(pthread_self());
+	for (i = 0; i < 12; i++)
+		for (j = 0; j < 4; j++) {
+			varray[i][j] = rand();
+			/* Don't want zero because it hides kernel problems */
+			if (varray[i][j] == 0)
+				j--;
+		}
+	rc = preempt_vsx(varray, &threads_starting, &running);
+	if (rc == 2)
+		fprintf(stderr, "Caught zeros in VSX compares\n");
+	return (void *)rc;
+}
+
+int test_preempt_vsx(void)
+{
+	int i, rc, threads;
+	pthread_t *tids;
+
+	SKIP_IF(!have_hwcap(PPC_FEATURE_HAS_VSX));
+
+	threads = sysconf(_SC_NPROCESSORS_ONLN) * THREAD_FACTOR;
+	tids = malloc(threads * sizeof(pthread_t));
+	FAIL_IF(!tids);
+
+	running = true;
+	threads_starting = threads;
+	for (i = 0; i < threads; i++) {
+		rc = pthread_create(&tids[i], NULL, preempt_vsx_c, NULL);
+		FAIL_IF(rc);
+	}
+
+	setbuf(stdout, NULL);
+	/* Not really nessesary but nice to wait for every thread to start */
+	printf("\tWaiting for %d workers to start...", threads_starting);
+	while(threads_starting)
+		asm volatile("": : :"memory");
+	printf("done\n");
+
+	printf("\tWaiting for %d seconds to let some workers get preempted...", PREEMPT_TIME);
+	sleep(PREEMPT_TIME);
+	printf("done\n");
+
+	printf("\tStopping workers...");
+	/*
+	 * Working are checking this value every loop. In preempt_vsx 'cmpwi r5,0; bne 2b'.
+	 * r5 will have loaded the value of running.
+	 */
+	running = 0;
+	for (i = 0; i < threads; i++) {
+		void *rc_p;
+		pthread_join(tids[i], &rc_p);
+
+		/*
+		 * Harness will say the fail was here, look at why preempt_vsx
+		 * returned
+		 */
+		if ((long) rc_p)
+			printf("oops\n");
+		FAIL_IF((long) rc_p);
+	}
+	printf("done\n");
+
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	return test_harness(test_preempt_vsx, "vsx_preempt");
+}