1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* perf events self profiling example test case for hw breakpoints.
*
* This tests perf PERF_TYPE_BREAKPOINT parameters
* 1) tests all variants of the break on read/write flags
* 2) tests exclude_user == 0 and 1
* 3) test array matches (if DAWR is supported))
* 4) test different numbers of breakpoints matches
*
* Configure this breakpoint, then read and write the data a number of
* times. Then check the output count from perf is as expected.
*
* Based on:
* http://ozlabs.org/~anton/junkcode/perf_events_example1.c
*
* Copyright (C) 2018 Michael Neuling, IBM Corporation.
*/
#include <unistd.h>
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <elf.h>
#include <pthread.h>
#include <sys/syscall.h>
#include <linux/perf_event.h>
#include <linux/hw_breakpoint.h>
#include "utils.h"
#define MAX_LOOPS 10000
#define DAWR_LENGTH_MAX ((0x3f + 1) * 8)
static inline int sys_perf_event_open(struct perf_event_attr *attr, pid_t pid,
int cpu, int group_fd,
unsigned long flags)
{
attr->size = sizeof(*attr);
return syscall(__NR_perf_event_open, attr, pid, cpu, group_fd, flags);
}
static inline bool breakpoint_test(int len)
{
struct perf_event_attr attr;
int fd;
/* setup counters */
memset(&attr, 0, sizeof(attr));
attr.disabled = 1;
attr.type = PERF_TYPE_BREAKPOINT;
attr.bp_type = HW_BREAKPOINT_R;
/* bp_addr can point anywhere but needs to be aligned */
attr.bp_addr = (__u64)(&attr) & 0xfffffffffffff800;
attr.bp_len = len;
fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
if (fd < 0)
return false;
close(fd);
return true;
}
static inline bool perf_breakpoint_supported(void)
{
return breakpoint_test(4);
}
static inline bool dawr_supported(void)
{
return breakpoint_test(DAWR_LENGTH_MAX);
}
static int runtestsingle(int readwriteflag, int exclude_user, int arraytest)
{
int i,j;
struct perf_event_attr attr;
size_t res;
unsigned long long breaks, needed;
int readint;
int readintarraybig[2*DAWR_LENGTH_MAX/sizeof(int)];
int *readintalign;
volatile int *ptr;
int break_fd;
int loop_num = MAX_LOOPS - (rand() % 100); /* provide some variability */
volatile int *k;
/* align to 0x400 boundary as required by DAWR */
readintalign = (int *)(((unsigned long)readintarraybig + 0x7ff) &
0xfffffffffffff800);
ptr = &readint;
if (arraytest)
ptr = &readintalign[0];
/* setup counters */
memset(&attr, 0, sizeof(attr));
attr.disabled = 1;
attr.type = PERF_TYPE_BREAKPOINT;
attr.bp_type = readwriteflag;
attr.bp_addr = (__u64)ptr;
attr.bp_len = sizeof(int);
if (arraytest)
attr.bp_len = DAWR_LENGTH_MAX;
attr.exclude_user = exclude_user;
break_fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
if (break_fd < 0) {
perror("sys_perf_event_open");
exit(1);
}
/* start counters */
ioctl(break_fd, PERF_EVENT_IOC_ENABLE);
/* Test a bunch of reads and writes */
k = &readint;
for (i = 0; i < loop_num; i++) {
if (arraytest)
k = &(readintalign[i % (DAWR_LENGTH_MAX/sizeof(int))]);
j = *k;
*k = j;
}
/* stop counters */
ioctl(break_fd, PERF_EVENT_IOC_DISABLE);
/* read and check counters */
res = read(break_fd, &breaks, sizeof(unsigned long long));
assert(res == sizeof(unsigned long long));
/* we read and write each loop, so subtract the ones we are counting */
needed = 0;
if (readwriteflag & HW_BREAKPOINT_R)
needed += loop_num;
if (readwriteflag & HW_BREAKPOINT_W)
needed += loop_num;
needed = needed * (1 - exclude_user);
printf("TESTED: addr:0x%lx brks:% 8lld loops:% 8i rw:%i !user:%i array:%i\n",
(unsigned long int)ptr, breaks, loop_num, readwriteflag, exclude_user, arraytest);
if (breaks != needed) {
printf("FAILED: 0x%lx brks:%lld needed:%lli %i %i %i\n\n",
(unsigned long int)ptr, breaks, needed, loop_num, readwriteflag, exclude_user);
return 1;
}
close(break_fd);
return 0;
}
static int runtest(void)
{
int rwflag;
int exclude_user;
int ret;
/*
* perf defines rwflag as two bits read and write and at least
* one must be set. So range 1-3.
*/
for (rwflag = 1 ; rwflag < 4; rwflag++) {
for (exclude_user = 0 ; exclude_user < 2; exclude_user++) {
ret = runtestsingle(rwflag, exclude_user, 0);
if (ret)
return ret;
/* if we have the dawr, we can do an array test */
if (!dawr_supported())
continue;
ret = runtestsingle(rwflag, exclude_user, 1);
if (ret)
return ret;
}
}
return 0;
}
static int perf_hwbreak(void)
{
srand ( time(NULL) );
SKIP_IF(!perf_breakpoint_supported());
return runtest();
}
int main(int argc, char *argv[], char **envp)
{
return test_harness(perf_hwbreak, "perf_hwbreak");
}
|
