1 /*
2 * Copyright 2014, Michael Ellerman, IBM Corp.
3 * Licensed under GPLv2.
4 */
5
6 #include <signal.h>
7 #include <stdio.h>
8 #include <stdlib.h>
9 #include <stdbool.h>
10 #include <sys/types.h>
11 #include <sys/wait.h>
12 #include <unistd.h>
13 #include <setjmp.h>
14 #include <signal.h>
15
16 #include "ebb.h"
17
18
19 /*
20 * Test that a fork clears the PMU state of the child. eg. BESCR/EBBHR/EBBRR
21 * are cleared, and MMCR0_PMCC is reset, preventing the child from accessing
22 * the PMU.
23 */
24
25 static struct event event;
26
child(void)27 static int child(void)
28 {
29 /* Even though we have EBE=0 we can still see the EBB regs */
30 FAIL_IF(mfspr(SPRN_BESCR) != 0);
31 FAIL_IF(mfspr(SPRN_EBBHR) != 0);
32 FAIL_IF(mfspr(SPRN_EBBRR) != 0);
33
34 FAIL_IF(catch_sigill(write_pmc1));
35
36 /* We can still read from the event, though it is on our parent */
37 FAIL_IF(event_read(&event));
38
39 return 0;
40 }
41
42 /* Tests that fork clears EBB state */
fork_cleanup(void)43 int fork_cleanup(void)
44 {
45 pid_t pid;
46
47 SKIP_IF(!ebb_is_supported());
48
49 event_init_named(&event, 0x1001e, "cycles");
50 event_leader_ebb_init(&event);
51
52 FAIL_IF(event_open(&event));
53
54 ebb_enable_pmc_counting(1);
55 setup_ebb_handler(standard_ebb_callee);
56 ebb_global_enable();
57
58 FAIL_IF(ebb_event_enable(&event));
59
60 mtspr(SPRN_MMCR0, MMCR0_FC);
61 mtspr(SPRN_PMC1, pmc_sample_period(sample_period));
62
63 /* Don't need to actually take any EBBs */
64
65 pid = fork();
66 if (pid == 0)
67 exit(child());
68
69 /* Child does the actual testing */
70 FAIL_IF(wait_for_child(pid));
71
72 /* After fork */
73 event_close(&event);
74
75 return 0;
76 }
77
main(void)78 int main(void)
79 {
80 return test_harness(fork_cleanup, "fork_cleanup");
81 }
82