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
20 int 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
75 again:
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
139 int main(int argc, char *argv[])
140 {
141 return test_harness(rfi_flush_test, "rfi_flush_test");
142 }
143
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