task_event_vs_ebb_test.c

 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 a per-task event vs an EBB - in that order. The EBB should push the
19 * per-task event off the PMU.
20 */
21
22static int setup_child_event(struct event *event, pid_t child_pid)
23{
24	event_init_named(event, 0x400FA, "PM_RUN_INST_CMPL");
25
26	event->attr.exclude_kernel = 1;
27	event->attr.exclude_hv = 1;
28	event->attr.exclude_idle = 1;
29
30	FAIL_IF(event_open_with_pid(event, child_pid));
31	FAIL_IF(event_enable(event));
32
33	return 0;
34}
35
36int task_event_vs_ebb(void)
37{
38	union pipe read_pipe, write_pipe;
39	struct event event;
40	pid_t pid;
41	int rc;
42
43	SKIP_IF(!ebb_is_supported());
44
45	FAIL_IF(pipe(read_pipe.fds) == -1);
46	FAIL_IF(pipe(write_pipe.fds) == -1);
47
48	pid = fork();
49	if (pid == 0) {
50		/* NB order of pipes looks reversed */
51		exit(ebb_child(write_pipe, read_pipe));
52	}
53
54	/* We setup the task event first */
55	rc = setup_child_event(&event, pid);
56	if (rc) {
57		kill_child_and_wait(pid);
58		return rc;
59	}
60
61	/* Signal the child to install its EBB event and wait */
62	if (sync_with_child(read_pipe, write_pipe))
63		/* If it fails, wait for it to exit */
64		goto wait;
65
66	/* Signal the child to run */
67	FAIL_IF(sync_with_child(read_pipe, write_pipe));
68
69wait:
70	/* The EBB event should push the task event off so the child should succeed */
71	FAIL_IF(wait_for_child(pid));
72	FAIL_IF(event_disable(&event));
73	FAIL_IF(event_read(&event));
74
75	event_report(&event);
76
77	/* The task event may have run, or not so we can't assert anything about it */
78
79	return 0;
80}
81
82int main(void)
83{
84	return test_harness(task_event_vs_ebb, "task_event_vs_ebb");
85}