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 FPU registers are correctly reported in a
10  * signal context. Each worker just spins checking its FPU registers, at some
11  * point a signal will interrupt it and C code will check the signal context
12  * ensuring it is also the same.
13  */
14 
15 #include <stdio.h>
16 #include <unistd.h>
17 #include <sys/syscall.h>
18 #include <sys/time.h>
19 #include <sys/types.h>
20 #include <sys/wait.h>
21 #include <stdlib.h>
22 #include <pthread.h>
23 
24 #include "utils.h"
25 
26 /* Number of times each thread should receive the signal */
27 #define ITERATIONS 10
28 /*
29  * Factor by which to multiply number of online CPUs for total number of
30  * worker threads
31  */
32 #define THREAD_FACTOR 8
33 
34 __thread double darray[] = {0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0,
35 		     1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0,
36 		     2.1};
37 
38 bool bad_context;
39 int threads_starting;
40 int running;
41 
42 extern long preempt_fpu(double *darray, int *threads_starting, int *running);
43 
44 void signal_fpu_sig(int sig, siginfo_t *info, void *context)
45 {
46 	int i;
47 	ucontext_t *uc = context;
48 	mcontext_t *mc = &uc->uc_mcontext;
49 
50 	/* Only the non volatiles were loaded up */
51 	for (i = 14; i < 32; i++) {
52 		if (mc->fp_regs[i] != darray[i - 14]) {
53 			bad_context = true;
54 			break;
55 		}
56 	}
57 }
58 
59 void *signal_fpu_c(void *p)
60 {
61 	int i;
62 	long rc;
63 	struct sigaction act;
64 	act.sa_sigaction = signal_fpu_sig;
65 	act.sa_flags = SA_SIGINFO;
66 	rc = sigaction(SIGUSR1, &act, NULL);
67 	if (rc)
68 		return p;
69 
70 	srand(pthread_self());
71 	for (i = 0; i < 21; i++)
72 		darray[i] = rand();
73 
74 	rc = preempt_fpu(darray, &threads_starting, &running);
75 
76 	return (void *) rc;
77 }
78 
79 int test_signal_fpu(void)
80 {
81 	int i, j, rc, threads;
82 	void *rc_p;
83 	pthread_t *tids;
84 
85 	threads = sysconf(_SC_NPROCESSORS_ONLN) * THREAD_FACTOR;
86 	tids = malloc(threads * sizeof(pthread_t));
87 	FAIL_IF(!tids);
88 
89 	running = true;
90 	threads_starting = threads;
91 	for (i = 0; i < threads; i++) {
92 		rc = pthread_create(&tids[i], NULL, signal_fpu_c, NULL);
93 		FAIL_IF(rc);
94 	}
95 
96 	setbuf(stdout, NULL);
97 	printf("\tWaiting for all workers to start...");
98 	while (threads_starting)
99 		asm volatile("": : :"memory");
100 	printf("done\n");
101 
102 	printf("\tSending signals to all threads %d times...", ITERATIONS);
103 	for (i = 0; i < ITERATIONS; i++) {
104 		for (j = 0; j < threads; j++) {
105 			pthread_kill(tids[j], SIGUSR1);
106 		}
107 		sleep(1);
108 	}
109 	printf("done\n");
110 
111 	printf("\tStopping workers...");
112 	running = 0;
113 	for (i = 0; i < threads; i++) {
114 		pthread_join(tids[i], &rc_p);
115 
116 		/*
117 		 * Harness will say the fail was here, look at why signal_fpu
118 		 * returned
119 		 */
120 		if ((long) rc_p || bad_context)
121 			printf("oops\n");
122 		if (bad_context)
123 			fprintf(stderr, "\t!! bad_context is true\n");
124 		FAIL_IF((long) rc_p || bad_context);
125 	}
126 	printf("done\n");
127 
128 	free(tids);
129 	return 0;
130 }
131 
132 int main(int argc, char *argv[])
133 {
134 	return test_harness(test_signal_fpu, "fpu_signal");
135 }
136