1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | |
3 | /* |
4 | * Copyright 2018 IBM Corporation. |
5 | * Copyright 2020 Canonical Ltd. |
6 | */ |
7 | |
8 | #define __SANE_USERSPACE_TYPES__ |
9 | |
10 | #include <sys/types.h> |
11 | #include <stdint.h> |
12 | #include <malloc.h> |
13 | #include <unistd.h> |
14 | #include <signal.h> |
15 | #include <stdlib.h> |
16 | #include <string.h> |
17 | #include <stdio.h> |
18 | #include "utils.h" |
19 | #include "flush_utils.h" |
20 | |
21 | int uaccess_flush_test(void) |
22 | { |
23 | char *p; |
24 | int repetitions = 10; |
25 | int fd, passes = 0, iter, rc = 0; |
26 | struct perf_event_read v; |
27 | __u64 l1d_misses_total = 0; |
28 | unsigned long iterations = 100000, zero_size = 24 * 1024; |
29 | unsigned long l1d_misses_expected; |
30 | int rfi_flush_orig; |
31 | int entry_flush_orig; |
32 | int uaccess_flush, uaccess_flush_orig; |
33 | |
34 | SKIP_IF(geteuid() != 0); |
35 | |
36 | // The PMU event we use only works on Power7 or later |
37 | SKIP_IF(!have_hwcap(PPC_FEATURE_ARCH_2_06)); |
38 | |
39 | if (read_debugfs_int("powerpc/rfi_flush" , &rfi_flush_orig) < 0) { |
40 | perror("Unable to read powerpc/rfi_flush debugfs file" ); |
41 | SKIP_IF(1); |
42 | } |
43 | |
44 | if (read_debugfs_int("powerpc/entry_flush" , &entry_flush_orig) < 0) { |
45 | perror("Unable to read powerpc/entry_flush debugfs file" ); |
46 | SKIP_IF(1); |
47 | } |
48 | |
49 | if (read_debugfs_int("powerpc/uaccess_flush" , &uaccess_flush_orig) < 0) { |
50 | perror("Unable to read powerpc/entry_flush debugfs file" ); |
51 | SKIP_IF(1); |
52 | } |
53 | |
54 | if (rfi_flush_orig != 0) { |
55 | if (write_debugfs_int("powerpc/rfi_flush" , 0) < 0) { |
56 | perror("error writing to powerpc/rfi_flush debugfs file" ); |
57 | FAIL_IF(1); |
58 | } |
59 | } |
60 | |
61 | if (entry_flush_orig != 0) { |
62 | if (write_debugfs_int("powerpc/entry_flush" , 0) < 0) { |
63 | perror("error writing to powerpc/entry_flush debugfs file" ); |
64 | FAIL_IF(1); |
65 | } |
66 | } |
67 | |
68 | uaccess_flush = uaccess_flush_orig; |
69 | |
70 | fd = perf_event_open_counter(PERF_TYPE_HW_CACHE, PERF_L1D_READ_MISS_CONFIG, -1); |
71 | FAIL_IF(fd < 0); |
72 | |
73 | p = (char *)memalign(zero_size, CACHELINE_SIZE); |
74 | |
75 | FAIL_IF(perf_event_enable(fd)); |
76 | |
77 | // disable L1 prefetching |
78 | set_dscr(1); |
79 | |
80 | iter = repetitions; |
81 | |
82 | /* |
83 | * We expect to see l1d miss for each cacheline access when entry_flush |
84 | * is set. Allow a small variation on this. |
85 | */ |
86 | l1d_misses_expected = iterations * (zero_size / CACHELINE_SIZE - 2); |
87 | |
88 | again: |
89 | FAIL_IF(perf_event_reset(fd)); |
90 | |
91 | syscall_loop_uaccess(p, iterations, zero_size); |
92 | |
93 | FAIL_IF(read(fd, &v, sizeof(v)) != sizeof(v)); |
94 | |
95 | if (uaccess_flush && v.l1d_misses >= l1d_misses_expected) |
96 | passes++; |
97 | else if (!uaccess_flush && v.l1d_misses < (l1d_misses_expected / 2)) |
98 | passes++; |
99 | |
100 | l1d_misses_total += v.l1d_misses; |
101 | |
102 | while (--iter) |
103 | goto again; |
104 | |
105 | if (passes < repetitions) { |
106 | printf("FAIL (L1D misses with uaccess_flush=%d: %llu %c %lu) [%d/%d failures]\n" , |
107 | uaccess_flush, l1d_misses_total, uaccess_flush ? '<' : '>', |
108 | uaccess_flush ? repetitions * l1d_misses_expected : |
109 | repetitions * l1d_misses_expected / 2, |
110 | repetitions - passes, repetitions); |
111 | rc = 1; |
112 | } else { |
113 | printf("PASS (L1D misses with uaccess_flush=%d: %llu %c %lu) [%d/%d pass]\n" , |
114 | uaccess_flush, l1d_misses_total, uaccess_flush ? '>' : '<', |
115 | uaccess_flush ? repetitions * l1d_misses_expected : |
116 | repetitions * l1d_misses_expected / 2, |
117 | passes, repetitions); |
118 | } |
119 | |
120 | if (uaccess_flush == uaccess_flush_orig) { |
121 | uaccess_flush = !uaccess_flush_orig; |
122 | if (write_debugfs_int("powerpc/uaccess_flush" , uaccess_flush) < 0) { |
123 | perror("error writing to powerpc/uaccess_flush debugfs file" ); |
124 | return 1; |
125 | } |
126 | iter = repetitions; |
127 | l1d_misses_total = 0; |
128 | passes = 0; |
129 | goto again; |
130 | } |
131 | |
132 | perf_event_disable(fd); |
133 | close(fd); |
134 | |
135 | set_dscr(0); |
136 | |
137 | if (write_debugfs_int("powerpc/rfi_flush" , rfi_flush_orig) < 0) { |
138 | perror("unable to restore original value of powerpc/rfi_flush debugfs file" ); |
139 | return 1; |
140 | } |
141 | |
142 | if (write_debugfs_int("powerpc/entry_flush" , entry_flush_orig) < 0) { |
143 | perror("unable to restore original value of powerpc/entry_flush debugfs file" ); |
144 | return 1; |
145 | } |
146 | |
147 | if (write_debugfs_int("powerpc/uaccess_flush" , uaccess_flush_orig) < 0) { |
148 | perror("unable to restore original value of powerpc/uaccess_flush debugfs file" ); |
149 | return 1; |
150 | } |
151 | |
152 | return rc; |
153 | } |
154 | |
155 | int main(int argc, char *argv[]) |
156 | { |
157 | return test_harness(uaccess_flush_test, "uaccess_flush_test" ); |
158 | } |
159 | |