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/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
  12 static char *sample_buffer;
  13 static char *sample_buffer_pos;
  14 static int prof_running = 0;
  15
  16 void 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         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
  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         return count < SAMPLE_BUFFER_SIZE ? count : SAMPLE_BUFFER_SIZE;
  57 }
  58
  59 static const struct file_operations cris_proc_profile_operations = {
  60         .read           = read_cris_profile,
  61         .write          = write_cris_profile,
  62 };
  63
  64 static int __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 __initcall(init_cris_profile);
  85