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 | |