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
21int 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
88again:
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
155int main(int argc, char *argv[])
156{
157	return test_harness(uaccess_flush_test, "uaccess_flush_test");
158}
159