1/*
2 * Copyright 2014, Michael Ellerman, IBM Corp.
3 * Licensed under GPLv2.
4 */
5
6#include <stdio.h>
7#include <stdlib.h>
8#include <stdbool.h>
9
10#include "ebb.h"
11
12
13/*
14 * Test of counting cycles while using MMCR0_FC (freeze counters) to only count
15 * parts of the code. This is complicated by the fact that FC is set by the
16 * hardware when the event overflows. We may take the EBB after we have set FC,
17 * so we have to be careful about whether we clear FC at the end of the EBB
18 * handler or not.
19 */
20
21static bool counters_frozen = false;
22static int ebbs_while_frozen = 0;
23
24static void ebb_callee(void)
25{
26	uint64_t mask, val;
27
28	mask = MMCR0_PMAO | MMCR0_FC;
29
30	val = mfspr(SPRN_BESCR);
31	if (!(val & BESCR_PMEO)) {
32		ebb_state.stats.spurious++;
33		goto out;
34	}
35
36	ebb_state.stats.ebb_count++;
37	trace_log_counter(ebb_state.trace, ebb_state.stats.ebb_count);
38
39	val = mfspr(SPRN_MMCR0);
40	trace_log_reg(ebb_state.trace, SPRN_MMCR0, val);
41
42	if (counters_frozen) {
43		trace_log_string(ebb_state.trace, "frozen");
44		ebbs_while_frozen++;
45		mask &= ~MMCR0_FC;
46	}
47
48	count_pmc(1, sample_period);
49out:
50	reset_ebb_with_clear_mask(mask);
51}
52
53int cycles_with_freeze(void)
54{
55	struct event event;
56	uint64_t val;
57	bool fc_cleared;
58
59	event_init_named(&event, 0x1001e, "cycles");
60	event_leader_ebb_init(&event);
61
62	event.attr.exclude_kernel = 1;
63	event.attr.exclude_hv = 1;
64	event.attr.exclude_idle = 1;
65
66	FAIL_IF(event_open(&event));
67
68	setup_ebb_handler(ebb_callee);
69	ebb_global_enable();
70	FAIL_IF(ebb_event_enable(&event));
71
72	mtspr(SPRN_PMC1, pmc_sample_period(sample_period));
73
74	fc_cleared = false;
75
76	/* Make sure we loop until we take at least one EBB */
77	while ((ebb_state.stats.ebb_count < 20 && !fc_cleared) ||
78		ebb_state.stats.ebb_count < 1)
79	{
80		counters_frozen = false;
81		mb();
82		mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) & ~MMCR0_FC);
83
84		FAIL_IF(core_busy_loop());
85
86		counters_frozen = true;
87		mb();
88		mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) |  MMCR0_FC);
89
90		val = mfspr(SPRN_MMCR0);
91		if (! (val & MMCR0_FC)) {
92			printf("Outside of loop, FC NOT set MMCR0 0x%lx\n", val);
93			fc_cleared = true;
94		}
95	}
96
97	ebb_global_disable();
98	ebb_freeze_pmcs();
99
100	count_pmc(1, sample_period);
101
102	dump_ebb_state();
103
104	printf("EBBs while frozen %d\n", ebbs_while_frozen);
105
106	event_close(&event);
107
108	FAIL_IF(ebb_state.stats.ebb_count == 0);
109	FAIL_IF(fc_cleared);
110
111	return 0;
112}
113
114int main(void)
115{
116	return test_harness(cycles_with_freeze, "cycles_with_freeze");
117}
118