1#include <linux/init.h>
2#include <linux/errno.h>
3#include <linux/kernel.h>
4#include <linux/proc_fs.h>
5#include <linux/types.h>
6#include <asm/ptrace.h>
7#include <asm/uaccess.h>
8
9#define SAMPLE_BUFFER_SIZE 8192
10
11static char* sample_buffer;
12static char* sample_buffer_pos;
13static int prof_running = 0;
14
15void
16cris_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
39	if (p > SAMPLE_BUFFER_SIZE)
40		return 0;
41
42	if (p + count > SAMPLE_BUFFER_SIZE)
43		count = SAMPLE_BUFFER_SIZE - p;
44	if (copy_to_user(buf, sample_buffer + p,count))
45		return -EFAULT;
46
47	memset(sample_buffer + p, 0, count);
48	*ppos += count;
49
50	return count;
51}
52
53static ssize_t
54write_cris_profile(struct file *file, const char __user *buf,
55		   size_t count, loff_t *ppos)
56{
57	sample_buffer_pos = sample_buffer;
58	memset(sample_buffer, 0, SAMPLE_BUFFER_SIZE);
59}
60
61static const struct file_operations cris_proc_profile_operations = {
62	.read		= read_cris_profile,
63	.write		= write_cris_profile,
64};
65
66static int
67__init init_cris_profile(void)
68{
69	struct proc_dir_entry *entry;
70
71	sample_buffer = kmalloc(SAMPLE_BUFFER_SIZE, GFP_KERNEL);
72	if (!sample_buffer) {
73		return -ENOMEM;
74	}
75
76	sample_buffer_pos = sample_buffer;
77
78	entry = create_proc_entry("system_profile", S_IWUSR | S_IRUGO, NULL);
79	if (entry) {
80		entry->proc_fops = &cris_proc_profile_operations;
81		entry->size = SAMPLE_BUFFER_SIZE;
82	}
83	prof_running = 1;
84
85	return 0;
86}
87
88__initcall(init_cris_profile);
89