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
11 static char* sample_buffer;
12 static char* sample_buffer_pos;
13 static int prof_running = 0;
14
15 void
cris_profile_sample(struct pt_regs * regs)16 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
33 static ssize_t
read_cris_profile(struct file * file,char __user * buf,size_t count,loff_t * ppos)34 read_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
50 static ssize_t
write_cris_profile(struct file * file,const char __user * buf,size_t count,loff_t * ppos)51 write_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 }
57
58 static const struct file_operations cris_proc_profile_operations = {
59 .read = read_cris_profile,
60 .write = write_cris_profile,
61 };
62
63 static int
init_cris_profile(void)64 __init init_cris_profile(void)
65 {
66 struct proc_dir_entry *entry;
67
68 sample_buffer = kmalloc(SAMPLE_BUFFER_SIZE, GFP_KERNEL);
69 if (!sample_buffer) {
70 return -ENOMEM;
71 }
72
73 sample_buffer_pos = sample_buffer;
74
75 entry = proc_create("system_profile", S_IWUSR | S_IRUGO, NULL,
76 &cris_proc_profile_operations);
77 if (entry) {
78 entry->size = SAMPLE_BUFFER_SIZE;
79 }
80 prof_running = 1;
81
82 return 0;
83 }
84
85 __initcall(init_cris_profile);
86