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
|
/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/perf_event.h>
#include <linux/types.h>
#include <linux/tracepoint.h>
#include <linux/fs.h>
#include <linux/debugfs.h>
#include <linux/preempt.h>
#include <linux/stat.h>
#include <asm/uaccess.h>
#define CREATE_TRACE_POINTS
#include "perf_trace_user.h"
#undef TRACE_SYSTEM
#define TRACE_SYSTEM perf_trace_counters
#define TRACE_USER_MAX_BUF_SIZE 100
u32 perf_num_l2ctrs;
static int perf_trace_write(struct file *file,
const char __user *user_string_in,
size_t len, loff_t *ppos)
{
u32 cnten_val;
u32 bit;
u32 cpu;
u32 num_cores = nr_cpu_ids;
u32 l2_enmask;
u32 l2_cnten_val;
unsigned long idx;
int i;
int rc;
char buf[TRACE_USER_MAX_BUF_SIZE + 1];
int length;
if (len == 0)
return 0;
length = len > TRACE_USER_MAX_BUF_SIZE ? TRACE_USER_MAX_BUF_SIZE : len;
rc = copy_from_user(buf, user_string_in, length);
/* Remove any trailing newline and make sure string is terminated */
if (buf[length - 1] == '\n')
buf[length - 1] = '\0';
else
buf[length] = '\0';
/*
* Disable preemption to ensure that all the performance counter
* accesses happen on the same cpu
*/
preempt_disable();
cpu = smp_processor_id();
/* stop counters, call the trace function, restart them */
/* Read PMCNTENSET */
asm volatile("mrc p15, 0, %0, c9, c12, 1" : "=r"(cnten_val));
/* Disable all the counters that were enabled */
asm volatile("mcr p15, 0, %0, c9, c12, 2" : : "r"(cnten_val));
l2_cnten_val = get_l2_indirect_reg(L2PMCNTENSET);
l2_enmask = 0;
for (i = 0; i < NUM_L2_PERCPU; i++) {
/*
* Assign L2 counters to cores sequentially
* starting from zero. A core could have
* multiple L2 counters allocated if # L2
* counters is more than the # cores
*/
idx = cpu + (num_cores * i);
bit = BIT(idx);
if (idx < perf_num_l2ctrs && (l2_cnten_val & bit)) {
/* Disable */
set_l2_indirect_reg(L2PMCNTENCLR, bit);
l2_enmask |= bit;
}
}
trace_perf_trace_user(buf, cnten_val, l2_enmask);
/* Enable L2*/
set_l2_indirect_reg(L2PMCNTENSET, l2_enmask);
/* Enable all the counters that were disabled */
asm volatile("mcr p15, 0, %0, c9, c12, 1" : : "r"(cnten_val));
preempt_enable();
return length;
}
static const struct file_operations perf_trace_fops = {
.write = perf_trace_write
};
static int __init init_perf_trace(void)
{
u32 val;
struct dentry *dir;
struct dentry *file;
unsigned int value = 1;
dir = perf_create_debug_dir();
if (!dir)
return -ENOMEM;
file = debugfs_create_file("trace_marker", S_IWUSR | S_IWGRP, dir,
&value, &perf_trace_fops);
if (!file)
return -ENOMEM;
val = get_l2_indirect_reg(L2PMCR);
perf_num_l2ctrs = ((val >> 11) & 0x1f) + 1;
return 0;
}
late_initcall(init_perf_trace);
|
