1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright 2015, Cyril Bur, IBM Corp.
4  *
5  * This test attempts to see if the VMX registers change across preemption.
6  * Two things should be noted here a) The check_vmx function in asm only checks
7  * the non volatile registers as it is reused from the syscall test b) There is
8  * no way to be sure preemption happened so this test just uses many threads
9  * and a long wait. As such, a successful test doesn't mean much but a failure
10  * is bad.
11  */
12 
13 #include <stdio.h>
14 #include <unistd.h>
15 #include <sys/syscall.h>
16 #include <sys/time.h>
17 #include <sys/types.h>
18 #include <sys/wait.h>
19 #include <stdlib.h>
20 #include <pthread.h>
21 
22 #include "utils.h"
23 
24 /* Time to wait for workers to get preempted (seconds) */
25 #define PREEMPT_TIME 20
26 /*
27  * Factor by which to multiply number of online CPUs for total number of
28  * worker threads
29  */
30 #define THREAD_FACTOR 8
31 
32 __thread vector int varray[] = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10,11,12},
33 	{13,14,15,16},{17,18,19,20},{21,22,23,24},
34 	{25,26,27,28},{29,30,31,32},{33,34,35,36},
35 	{37,38,39,40},{41,42,43,44},{45,46,47,48}};
36 
37 int threads_starting;
38 int running;
39 
40 extern int preempt_vmx(vector int *varray, int *threads_starting, int *running);
41 
preempt_vmx_c(void * p)42 void *preempt_vmx_c(void *p)
43 {
44 	int i, j;
45 	long rc;
46 
47 	srand(pthread_self());
48 	for (i = 0; i < 12; i++)
49 		for (j = 0; j < 4; j++)
50 			varray[i][j] = rand();
51 
52 	rc = preempt_vmx(varray, &threads_starting, &running);
53 
54 	return (void *)rc;
55 }
56 
test_preempt_vmx(void)57 int test_preempt_vmx(void)
58 {
59 	int i, rc, threads;
60 	pthread_t *tids;
61 
62 	// vcmpequd used in vmx_asm.S is v2.07
63 	SKIP_IF(!have_hwcap2(PPC_FEATURE2_ARCH_2_07));
64 
65 	threads = sysconf(_SC_NPROCESSORS_ONLN) * THREAD_FACTOR;
66 	tids = malloc(threads * sizeof(pthread_t));
67 	FAIL_IF(!tids);
68 
69 	running = true;
70 	threads_starting = threads;
71 	for (i = 0; i < threads; i++) {
72 		rc = pthread_create(&tids[i], NULL, preempt_vmx_c, NULL);
73 		FAIL_IF(rc);
74 	}
75 
76 	setbuf(stdout, NULL);
77 	/* Not really nessesary but nice to wait for every thread to start */
78 	printf("\tWaiting for all workers to start...");
79 	while(threads_starting)
80 		asm volatile("": : :"memory");
81 	printf("done\n");
82 
83 	printf("\tWaiting for %d seconds to let some workers get preempted...", PREEMPT_TIME);
84 	sleep(PREEMPT_TIME);
85 	printf("done\n");
86 
87 	printf("\tStopping workers...");
88 	/*
89 	 * Working are checking this value every loop. In preempt_vmx 'cmpwi r5,0; bne 2b'.
90 	 * r5 will have loaded the value of running.
91 	 */
92 	running = 0;
93 	for (i = 0; i < threads; i++) {
94 		void *rc_p;
95 		pthread_join(tids[i], &rc_p);
96 
97 		/*
98 		 * Harness will say the fail was here, look at why preempt_vmx
99 		 * returned
100 		 */
101 		if ((long) rc_p)
102 			printf("oops\n");
103 		FAIL_IF((long) rc_p);
104 	}
105 	printf("done\n");
106 
107 	return 0;
108 }
109 
main(int argc,char * argv[])110 int main(int argc, char *argv[])
111 {
112 	return test_harness(test_preempt_vmx, "vmx_preempt");
113 }
114