1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright 2014, Michael Ellerman, IBM Corp.
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
15 #include "ebb.h"
16
17
18 /*
19 * Test that a fork clears the PMU state of the child. eg. BESCR/EBBHR/EBBRR
20 * are cleared, and MMCR0_PMCC is reset, preventing the child from accessing
21 * the PMU.
22 */
23
24 static struct event event;
25
26 static int child(void)
27 {
28 /* Even though we have EBE=0 we can still see the EBB regs */
29 FAIL_IF(mfspr(SPRN_BESCR) != 0);
30 FAIL_IF(mfspr(SPRN_EBBHR) != 0);
31 FAIL_IF(mfspr(SPRN_EBBRR) != 0);
32
33 FAIL_IF(catch_sigill(write_pmc1));
34
35 /* We can still read from the event, though it is on our parent */
36 FAIL_IF(event_read(&event));
37
38 return 0;
39 }
40
41 /* Tests that fork clears EBB state */
42 int fork_cleanup(void)
43 {
44 pid_t pid;
45
46 SKIP_IF(!ebb_is_supported());
47
48 event_init_named(&event, 0x1001e, "cycles");
49 event_leader_ebb_init(&event);
50
51 FAIL_IF(event_open(&event));
52
53 ebb_enable_pmc_counting(1);
54 setup_ebb_handler(standard_ebb_callee);
55 ebb_global_enable();
56
57 FAIL_IF(ebb_event_enable(&event));
58
59 mtspr(SPRN_MMCR0, MMCR0_FC);
60 mtspr(SPRN_PMC1, pmc_sample_period(sample_period));
61
62 /* Don't need to actually take any EBBs */
63
64 pid = fork();
65 if (pid == 0)
66 exit(child());
67
68 /* Child does the actual testing */
69 FAIL_IF(wait_for_child(pid));
70
71 /* After fork */
72 event_close(&event);
73
74 return 0;
75 }
76
77 int main(void)
78 {
79 return test_harness(fork_cleanup, "fork_cleanup");
80 }
81
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