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
18 #define CACHELINE_SIZE 128
19
20 struct perf_event_read {
21 __u64 nr;
22 __u64 l1d_misses;
23 };
24
load(void * addr)25 static inline __u64 load(void *addr)
26 {
27 __u64 tmp;
28
29 asm volatile("ld %0,0(%1)" : "=r"(tmp) : "b"(addr));
30
31 return tmp;
32 }
33
syscall_loop(char * p,unsigned long iterations,unsigned long zero_size)34 static void syscall_loop(char *p, unsigned long iterations,
35 unsigned long zero_size)
36 {
37 for (unsigned long i = 0; i < iterations; i++) {
38 for (unsigned long j = 0; j < zero_size; j += CACHELINE_SIZE)
39 load(p + j);
40 getppid();
41 }
42 }
43
rfi_flush_test(void)44 int rfi_flush_test(void)
45 {
46 char *p;
47 int repetitions = 10;
48 int fd, passes = 0, iter, rc = 0;
49 struct perf_event_read v;
50 __u64 l1d_misses_total = 0;
51 unsigned long iterations = 100000, zero_size = 24 * 1024;
52 unsigned long l1d_misses_expected;
53 int rfi_flush_org, rfi_flush;
54
55 SKIP_IF(geteuid() != 0);
56
57 if (read_debugfs_file("powerpc/rfi_flush", &rfi_flush_org)) {
58 perror("Unable to read powerpc/rfi_flush debugfs file");
59 SKIP_IF(1);
60 }
61
62 rfi_flush = rfi_flush_org;
63
64 fd = perf_event_open_counter(PERF_TYPE_RAW, /* L1d miss */ 0x400f0, -1);
65 FAIL_IF(fd < 0);
66
67 p = (char *)memalign(zero_size, CACHELINE_SIZE);
68
69 FAIL_IF(perf_event_enable(fd));
70
71 set_dscr(1);
72
73 iter = repetitions;
74
75 /*
76 * We expect to see l1d miss for each cacheline access when rfi_flush
77 * is set. Allow a small variation on this.
78 */
79 l1d_misses_expected = iterations * (zero_size / CACHELINE_SIZE - 2);
80
81 again:
82 FAIL_IF(perf_event_reset(fd));
83
84 syscall_loop(p, iterations, zero_size);
85
86 FAIL_IF(read(fd, &v, sizeof(v)) != sizeof(v));
87
88 if (rfi_flush && v.l1d_misses >= l1d_misses_expected)
89 passes++;
90 else if (!rfi_flush && v.l1d_misses < (l1d_misses_expected / 2))
91 passes++;
92
93 l1d_misses_total += v.l1d_misses;
94
95 while (--iter)
96 goto again;
97
98 if (passes < repetitions) {
99 printf("FAIL (L1D misses with rfi_flush=%d: %llu %c %lu) [%d/%d failures]\n",
100 rfi_flush, l1d_misses_total, rfi_flush ? '<' : '>',
101 rfi_flush ? repetitions * l1d_misses_expected :
102 repetitions * l1d_misses_expected / 2,
103 repetitions - passes, repetitions);
104 rc = 1;
105 } else
106 printf("PASS (L1D misses with rfi_flush=%d: %llu %c %lu) [%d/%d pass]\n",
107 rfi_flush, l1d_misses_total, rfi_flush ? '>' : '<',
108 rfi_flush ? repetitions * l1d_misses_expected :
109 repetitions * l1d_misses_expected / 2,
110 passes, repetitions);
111
112 if (rfi_flush == rfi_flush_org) {
113 rfi_flush = !rfi_flush_org;
114 if (write_debugfs_file("powerpc/rfi_flush", rfi_flush) < 0) {
115 perror("error writing to powerpc/rfi_flush debugfs file");
116 return 1;
117 }
118 iter = repetitions;
119 l1d_misses_total = 0;
120 passes = 0;
121 goto again;
122 }
123
124 perf_event_disable(fd);
125 close(fd);
126
127 set_dscr(0);
128
129 if (write_debugfs_file("powerpc/rfi_flush", rfi_flush_org) < 0) {
130 perror("unable to restore original value of powerpc/rfi_flush debugfs file");
131 return 1;
132 }
133
134 return rc;
135 }
136
main(int argc,char * argv[])137 int main(int argc, char *argv[])
138 {
139 return test_harness(rfi_flush_test, "rfi_flush_test");
140 }
141