1 /*
2  * Copyright 2015, Cyril Bur, IBM Corp.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License
6  * as published by the Free Software Foundation; either version
7  * 2 of the License, or (at your option) any later version.
8  *
9  * This test attempts to see if the VMX registers change across preemption.
10  * Two things should be noted here a) The check_vmx function in asm only checks
11  * the non volatile registers as it is reused from the syscall test b) There is
12  * no way to be sure preemption happened so this test just uses many threads
13  * and a long wait. As such, a successful test doesn't mean much but a failure
14  * is bad.
15  */
16 
17 #include <stdio.h>
18 #include <unistd.h>
19 #include <sys/syscall.h>
20 #include <sys/time.h>
21 #include <sys/types.h>
22 #include <sys/wait.h>
23 #include <stdlib.h>
24 #include <pthread.h>
25 
26 #include "utils.h"
27 
28 /* Time to wait for workers to get preempted (seconds) */
29 #define PREEMPT_TIME 20
30 /*
31  * Factor by which to multiply number of online CPUs for total number of
32  * worker threads
33  */
34 #define THREAD_FACTOR 8
35 
36 __thread vector int varray[] = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10,11,12},
37 	{13,14,15,16},{17,18,19,20},{21,22,23,24},
38 	{25,26,27,28},{29,30,31,32},{33,34,35,36},
39 	{37,38,39,40},{41,42,43,44},{45,46,47,48}};
40 
41 int threads_starting;
42 int running;
43 
44 extern void preempt_vmx(vector int *varray, int *threads_starting, int *running);
45 
46 void *preempt_vmx_c(void *p)
47 {
48 	int i, j;
49 	srand(pthread_self());
50 	for (i = 0; i < 12; i++)
51 		for (j = 0; j < 4; j++)
52 			varray[i][j] = rand();
53 
54 	/* Test fails if it ever returns */
55 	preempt_vmx(varray, &threads_starting, &running);
56 	return p;
57 }
58 
59 int test_preempt_vmx(void)
60 {
61 	int i, rc, threads;
62 	pthread_t *tids;
63 
64 	threads = sysconf(_SC_NPROCESSORS_ONLN) * THREAD_FACTOR;
65 	tids = malloc(threads * sizeof(pthread_t));
66 	FAIL_IF(!tids);
67 
68 	running = true;
69 	threads_starting = threads;
70 	for (i = 0; i < threads; i++) {
71 		rc = pthread_create(&tids[i], NULL, preempt_vmx_c, NULL);
72 		FAIL_IF(rc);
73 	}
74 
75 	setbuf(stdout, NULL);
76 	/* Not really nessesary but nice to wait for every thread to start */
77 	printf("\tWaiting for all workers to start...");
78 	while(threads_starting)
79 		asm volatile("": : :"memory");
80 	printf("done\n");
81 
82 	printf("\tWaiting for %d seconds to let some workers get preempted...", PREEMPT_TIME);
83 	sleep(PREEMPT_TIME);
84 	printf("done\n");
85 
86 	printf("\tStopping workers...");
87 	/*
88 	 * Working are checking this value every loop. In preempt_vmx 'cmpwi r5,0; bne 2b'.
89 	 * r5 will have loaded the value of running.
90 	 */
91 	running = 0;
92 	for (i = 0; i < threads; i++) {
93 		void *rc_p;
94 		pthread_join(tids[i], &rc_p);
95 
96 		/*
97 		 * Harness will say the fail was here, look at why preempt_vmx
98 		 * returned
99 		 */
100 		if ((long) rc_p)
101 			printf("oops\n");
102 		FAIL_IF((long) rc_p);
103 	}
104 	printf("done\n");
105 
106 	return 0;
107 }
108 
109 int main(int argc, char *argv[])
110 {
111 	return test_harness(test_preempt_vmx, "vmx_preempt");
112 }
113