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
14#include "ebb.h"
15
16
17/*
18 * Tests we can setup an EBB on our child. The child expects this and enables
19 * EBBs, which are then delivered to the child, even though the event is
20 * created by the parent.
21 */
22
23static int victim_child(union pipe read_pipe, union pipe write_pipe)
24{
25 FAIL_IF(wait_for_parent(read_pipe));
26
27 /* Setup our EBB handler, before the EBB event is created */
28 ebb_enable_pmc_counting(pmc: 1);
29 setup_ebb_handler(standard_ebb_callee);
30 ebb_global_enable();
31
32 FAIL_IF(notify_parent(write_pipe));
33
34 while (ebb_state.stats.ebb_count < 20) {
35 FAIL_IF(core_busy_loop());
36 }
37
38 ebb_global_disable();
39 ebb_freeze_pmcs();
40
41 dump_ebb_state();
42
43 FAIL_IF(ebb_state.stats.ebb_count == 0);
44
45 return 0;
46}
47
48/* Tests we can setup an EBB on our child - if it's expecting it */
49int ebb_on_willing_child(void)
50{
51 union pipe read_pipe, write_pipe;
52 struct event event;
53 pid_t pid;
54
55 SKIP_IF(!ebb_is_supported());
56
57 FAIL_IF(pipe(read_pipe.fds) == -1);
58 FAIL_IF(pipe(write_pipe.fds) == -1);
59
60 pid = fork();
61 if (pid == 0) {
62 /* NB order of pipes looks reversed */
63 exit(victim_child(read_pipe: write_pipe, write_pipe: read_pipe));
64 }
65
66 /* Signal the child to setup its EBB handler */
67 FAIL_IF(sync_with_child(read_pipe, write_pipe));
68
69 /* Child is running now */
70
71 event_init_named(e: &event, config: 0x1001e, name: "cycles");
72 event_leader_ebb_init(e: &event);
73
74 event.attr.exclude_kernel = 1;
75 event.attr.exclude_hv = 1;
76 event.attr.exclude_idle = 1;
77
78 FAIL_IF(event_open_with_pid(e: &event, pid));
79 FAIL_IF(ebb_event_enable(e: &event));
80
81 /* Child show now take EBBs and then exit */
82 FAIL_IF(wait_for_child(child_pid: pid));
83
84 event_close(e: &event);
85
86 return 0;
87}
88
89int main(void)
90{
91 return test_harness(ebb_on_willing_child, "ebb_on_willing_child");
92}
93

source code of linux/tools/testing/selftests/powerpc/pmu/ebb/ebb_on_willing_child_test.c