cpu_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 cpu event vs an EBB - in that order. The EBB should force the cpu
19 * event off the PMU.
20 */
21
22static int setup_cpu_event(struct event *event, int cpu)
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	SKIP_IF(require_paranoia_below(1));
31	FAIL_IF(event_open_with_cpu(event, cpu));
32	FAIL_IF(event_enable(event));
33
34	return 0;
35}
36
37int cpu_event_vs_ebb(void)
38{
39	union pipe read_pipe, write_pipe;
40	struct event event;
41	int cpu, rc;
42	pid_t pid;
43
44	SKIP_IF(!ebb_is_supported());
45
46	cpu = bind_to_cpu(BIND_CPU_ANY);
47	FAIL_IF(cpu < 0);
48
49	FAIL_IF(pipe(read_pipe.fds) == -1);
50	FAIL_IF(pipe(write_pipe.fds) == -1);
51
52	pid = fork();
53	if (pid == 0) {
54		/* NB order of pipes looks reversed */
55		exit(ebb_child(write_pipe, read_pipe));
56	}
57
58	/* We setup the cpu event first */
59	rc = setup_cpu_event(&event, cpu);
60	if (rc) {
61		kill_child_and_wait(pid);
62		return rc;
63	}
64
65	/* Signal the child to install its EBB event and wait */
66	if (sync_with_child(read_pipe, write_pipe))
67		/* If it fails, wait for it to exit */
68		goto wait;
69
70	/* Signal the child to run */
71	FAIL_IF(sync_with_child(read_pipe, write_pipe));
72
73wait:
74	/* We expect the child to succeed */
75	FAIL_IF(wait_for_child(pid));
76
77	FAIL_IF(event_disable(&event));
78	FAIL_IF(event_read(&event));
79
80	event_report(&event);
81
82	/* The cpu event may have run */
83
84	return 0;
85}
86
87int main(void)
88{
89	return test_harness(cpu_event_vs_ebb, "cpu_event_vs_ebb");
90}