1#include <linux/init.h>
2#include <linux/errno.h>
3#include <linux/kernel.h>
4#include <linux/proc_fs.h>
5#include <linux/slab.h>
6#include <linux/types.h>
7#include <asm/ptrace.h>
8#include <asm/uaccess.h>
9
10#define SAMPLE_BUFFER_SIZE 8192
11
12static char *sample_buffer;
13static char *sample_buffer_pos;
14static int prof_running = 0;
15
16void cris_profile_sample(struct pt_regs *regs)
17{
18	if (!prof_running)
19		return;
20
21	if (user_mode(regs))
22		*(unsigned int*)sample_buffer_pos = current->pid;
23	else
24		*(unsigned int*)sample_buffer_pos = 0;
25
26	*(unsigned int *)(sample_buffer_pos + 4) = instruction_pointer(regs);
27	sample_buffer_pos += 8;
28
29	if (sample_buffer_pos == sample_buffer + SAMPLE_BUFFER_SIZE)
30		sample_buffer_pos = sample_buffer;
31}
32
33static ssize_t
34read_cris_profile(struct file *file, char __user *buf,
35		  size_t count, loff_t *ppos)
36{
37	unsigned long p = *ppos;
38	ssize_t ret;
39
40	ret = simple_read_from_buffer(buf, count, ppos, sample_buffer,
41						SAMPLE_BUFFER_SIZE);
42	if (ret < 0)
43		return ret;
44
45	memset(sample_buffer + p, 0, ret);
46
47	return ret;
48}
49
50static ssize_t
51write_cris_profile(struct file *file, const char __user *buf,
52		   size_t count, loff_t *ppos)
53{
54	sample_buffer_pos = sample_buffer;
55	memset(sample_buffer, 0, SAMPLE_BUFFER_SIZE);
56	return count < SAMPLE_BUFFER_SIZE ? count : SAMPLE_BUFFER_SIZE;
57}
58
59static const struct file_operations cris_proc_profile_operations = {
60	.read		= read_cris_profile,
61	.write		= write_cris_profile,
62	.llseek		= default_llseek,
63};
64
65static int __init init_cris_profile(void)
66{
67	struct proc_dir_entry *entry;
68
69	sample_buffer = kmalloc(SAMPLE_BUFFER_SIZE, GFP_KERNEL);
70	if (!sample_buffer) {
71		return -ENOMEM;
72	}
73
74	sample_buffer_pos = sample_buffer;
75
76	entry = proc_create("system_profile", S_IWUSR | S_IRUGO, NULL,
77			    &cris_proc_profile_operations);
78	if (entry) {
79		proc_set_size(entry, SAMPLE_BUFFER_SIZE);
80	}
81	prof_running = 1;
82
83	return 0;
84}
85__initcall(init_cris_profile);
86
87