Re: [PATCH 1/5] selftests/powerpc: Check for VSX preservation across userspace preemption

+/*
+ * Copyright 2015, Cyril Bur, IBM Corp.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */

+
+#include "../basic_asm.h"
+#include "../vsx_asm.h"
+

+FUNC_START(check_vsx)
+	PUSH_BASIC_STACK(32)
+	std	r3,STACK_FRAME_PARAM(0)(sp)
+	addi r3, r3, 16 * 12 #Second half of array
+	bl store_vsx
+	ld r3,STACK_FRAME_PARAM(0)(sp)
+	bl vsx_memcmp
+	POP_BASIC_STACK(32)
+	blr
+FUNC_END(check_vsx)
+

+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, 16) == 0) {
+			fprintf(stderr, "Detected zero from the VSX reg %d\n", i + 12);
+			return 1;
+		}
+	}
+
+	if (memcmp(a, &a[12], 12 * 16)) {

+		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)

+	return (void *)rc;
+}
+
+int test_preempt_vsx(void)
+{
+	int i, rc, threads;
+	pthread_t *tids;
+
+	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;
+}
+