arch/cris/kernel/profile.c

   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
  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
  34 read_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
  53 static ssize_t
  54 write_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
  61 static const struct file_operations cris_proc_profile_operations = {
  62         .read           = read_cris_profile,
  63         .write          = write_cris_profile,
  64 };
  65
  66 static 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);