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   if (user_mode(regs))
  21     *(unsigned int*)sample_buffer_pos = current->pid;
  22   else
  23     *(unsigned int*)sample_buffer_pos = 0;
  24   *(unsigned int*)(sample_buffer_pos + 4) = instruction_pointer(regs);
  25   sample_buffer_pos += 8;
  26   if (sample_buffer_pos == sample_buffer + SAMPLE_BUFFER_SIZE)
  27     sample_buffer_pos = sample_buffer;
  28 }
  29
  30 static ssize_t
  31 read_cris_profile(struct file *file, char __user *buf, size_t count, loff_t *ppos)
  32 {
  33   unsigned long p = *ppos;
  34   if (p > SAMPLE_BUFFER_SIZE)
  35     return 0;
  36   if (p + count > SAMPLE_BUFFER_SIZE)
  37     count = SAMPLE_BUFFER_SIZE - p;
  38   if (copy_to_user(buf, sample_buffer + p,count))
  39                 return -EFAULT;
  40   memset(sample_buffer + p, 0, count);
  41   *ppos += count;
  42   return count;
  43 }
  44
  45 static ssize_t
  46 write_cris_profile(struct file *file, const char __user *buf,
  47               size_t count, loff_t *ppos)
  48 {
  49   sample_buffer_pos = sample_buffer;
  50   memset(sample_buffer, 0, SAMPLE_BUFFER_SIZE);
  51 }
  52
  53 static const struct file_operations cris_proc_profile_operations = {
  54         .read           = read_cris_profile,
  55         .write          = write_cris_profile,
  56 };
  57
  58 static int
  59 __init init_cris_profile(void)
  60 {
  61   struct proc_dir_entry *entry;
  62   sample_buffer = kmalloc(SAMPLE_BUFFER_SIZE, GFP_KERNEL);
  63   sample_buffer_pos = sample_buffer;
  64   entry = create_proc_entry("system_profile", S_IWUSR | S_IRUGO, NULL);
  65   if (entry) {
  66     entry->proc_fops = &cris_proc_profile_operations;
  67     entry->size = SAMPLE_BUFFER_SIZE;
  68   }
  69   prof_running = 1;
  70   return 0;
  71 }
  72
  73 __initcall(init_cris_profile);