1// SPDX-License-Identifier: GPL-2.0+
2
3/*
4 * Copyright 2018 IBM Corporation.
5 */
6
7#define __SANE_USERSPACE_TYPES__
8
9#include <sys/types.h>
10#include <stdint.h>
11#include <malloc.h>
12#include <unistd.h>
13#include <stdlib.h>
14#include <string.h>
15#include <stdio.h>
16#include "utils.h"
17#include "flush_utils.h"
18
19
20int rfi_flush_test(void)
21{
22	char *p;
23	int repetitions = 10;
24	int fd, passes = 0, iter, rc = 0;
25	struct perf_event_read v;
26	__u64 l1d_misses_total = 0;
27	unsigned long iterations = 100000, zero_size = 24 * 1024;
28	unsigned long l1d_misses_expected;
29	int rfi_flush_orig, rfi_flush;
30	int have_entry_flush, entry_flush_orig;
31
32	SKIP_IF(geteuid() != 0);
33
34	// The PMU event we use only works on Power7 or later
35	SKIP_IF(!have_hwcap(PPC_FEATURE_ARCH_2_06));
36
37	if (read_debugfs_int("powerpc/rfi_flush", &rfi_flush_orig) < 0) {
38		perror("Unable to read powerpc/rfi_flush debugfs file");
39		SKIP_IF(1);
40	}
41
42	if (read_debugfs_int("powerpc/entry_flush", &entry_flush_orig) < 0) {
43		have_entry_flush = 0;
44	} else {
45		have_entry_flush = 1;
46
47		if (entry_flush_orig != 0) {
48			if (write_debugfs_int("powerpc/entry_flush", 0) < 0) {
49				perror("error writing to powerpc/entry_flush debugfs file");
50				return 1;
51			}
52		}
53	}
54
55	rfi_flush = rfi_flush_orig;
56
57	fd = perf_event_open_counter(PERF_TYPE_HW_CACHE, PERF_L1D_READ_MISS_CONFIG, -1);
58	FAIL_IF(fd < 0);
59
60	p = (char *)memalign(zero_size, CACHELINE_SIZE);
61
62	FAIL_IF(perf_event_enable(fd));
63
64	// disable L1 prefetching
65	set_dscr(1);
66
67	iter = repetitions;
68
69	/*
70	 * We expect to see l1d miss for each cacheline access when rfi_flush
71	 * is set. Allow a small variation on this.
72	 */
73	l1d_misses_expected = iterations * (zero_size / CACHELINE_SIZE - 2);
74
75again:
76	FAIL_IF(perf_event_reset(fd));
77
78	syscall_loop(p, iterations, zero_size);
79
80	FAIL_IF(read(fd, &v, sizeof(v)) != sizeof(v));
81
82	if (rfi_flush && v.l1d_misses >= l1d_misses_expected)
83		passes++;
84	else if (!rfi_flush && v.l1d_misses < (l1d_misses_expected / 2))
85		passes++;
86
87	l1d_misses_total += v.l1d_misses;
88
89	while (--iter)
90		goto again;
91
92	if (passes < repetitions) {
93		printf("FAIL (L1D misses with rfi_flush=%d: %llu %c %lu) [%d/%d failures]\n",
94		       rfi_flush, l1d_misses_total, rfi_flush ? '<' : '>',
95		       rfi_flush ? repetitions * l1d_misses_expected :
96		       repetitions * l1d_misses_expected / 2,
97		       repetitions - passes, repetitions);
98		rc = 1;
99	} else
100		printf("PASS (L1D misses with rfi_flush=%d: %llu %c %lu) [%d/%d pass]\n",
101		       rfi_flush, l1d_misses_total, rfi_flush ? '>' : '<',
102		       rfi_flush ? repetitions * l1d_misses_expected :
103		       repetitions * l1d_misses_expected / 2,
104		       passes, repetitions);
105
106	if (rfi_flush == rfi_flush_orig) {
107		rfi_flush = !rfi_flush_orig;
108		if (write_debugfs_int("powerpc/rfi_flush", rfi_flush) < 0) {
109			perror("error writing to powerpc/rfi_flush debugfs file");
110			return 1;
111		}
112		iter = repetitions;
113		l1d_misses_total = 0;
114		passes = 0;
115		goto again;
116	}
117
118	perf_event_disable(fd);
119	close(fd);
120
121	set_dscr(0);
122
123	if (write_debugfs_int("powerpc/rfi_flush", rfi_flush_orig) < 0) {
124		perror("unable to restore original value of powerpc/rfi_flush debugfs file");
125		return 1;
126	}
127
128	if (have_entry_flush) {
129		if (write_debugfs_int("powerpc/entry_flush", entry_flush_orig) < 0) {
130			perror("unable to restore original value of powerpc/entry_flush "
131			       "debugfs file");
132			return 1;
133		}
134	}
135
136	return rc;
137}
138
139int main(int argc, char *argv[])
140{
141	return test_harness(rfi_flush_test, "rfi_flush_test");
142}
143