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 
23 static 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(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 */
49 int 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(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(&event, 0x1001e, "cycles");
72 	event_leader_ebb_init(&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(&event, pid));
79 	FAIL_IF(ebb_event_enable(&event));
80 
81 	/* Child show now take EBBs and then exit */
82 	FAIL_IF(wait_for_child(pid));
83 
84 	event_close(&event);
85 
86 	return 0;
87 }
88 
89 int main(void)
90 {
91 	return test_harness(ebb_on_willing_child, "ebb_on_willing_child");
92 }
93