drivers/oprofile/oprofile_files.c

   1 /**
   2  * @file oprofile_files.c
   3  *
   4  * @remark Copyright 2002 OProfile authors
   5  * @remark Read the file COPYING
   6  *
   7  * @author John Levon <levon@movementarian.org>
   8  */
   9
  10 #include <linux/fs.h>
  11 #include <linux/oprofile.h>
  12
  13 #include "event_buffer.h"
  14 #include "oprofile_stats.h"
  15 #include "oprof.h"
  16
  17 unsigned long fs_buffer_size = 131072;
  18 unsigned long fs_cpu_buffer_size = 8192;
  19 unsigned long fs_buffer_watershed = 32768; /* FIXME: tune */
  20
  21 static ssize_t depth_read(struct file * file, char __user * buf, size_t count, loff_t * offset)
  22 {
  23         return oprofilefs_ulong_to_user(backtrace_depth, buf, count, offset);
  24 }
  25
  26
  27 static ssize_t depth_write(struct file * file, char const __user * buf, size_t count, loff_t * offset)
  28 {
  29         unsigned long val;
  30         int retval;
  31
  32         if (*offset)
  33                 return -EINVAL;
  34
  35         retval = oprofilefs_ulong_from_user(&val, buf, count);
  36         if (retval)
  37                 return retval;
  38
  39         retval = oprofile_set_backtrace(val);
  40
  41         if (retval)
  42                 return retval;
  43         return count;
  44 }
  45
  46
  47 static const struct file_operations depth_fops = {
  48         .read           = depth_read,
  49         .write          = depth_write
  50 };
  51
  52
  53 static ssize_t pointer_size_read(struct file * file, char __user * buf, size_t count, loff_t * offset)
  54 {
  55         return oprofilefs_ulong_to_user(sizeof(void *), buf, count, offset);
  56 }
  57
  58
  59 static const struct file_operations pointer_size_fops = {
  60         .read           = pointer_size_read,
  61 };
  62
  63
  64 static ssize_t cpu_type_read(struct file * file, char __user * buf, size_t count, loff_t * offset)
  65 {
  66         return oprofilefs_str_to_user(oprofile_ops.cpu_type, buf, count, offset);
  67 }
  68
  69
  70 static const struct file_operations cpu_type_fops = {
  71         .read           = cpu_type_read,
  72 };
  73
  74
  75 static ssize_t enable_read(struct file * file, char __user * buf, size_t count, loff_t * offset)
  76 {
  77         return oprofilefs_ulong_to_user(oprofile_started, buf, count, offset);
  78 }
  79
  80
  81 static ssize_t enable_write(struct file * file, char const __user * buf, size_t count, loff_t * offset)
  82 {
  83         unsigned long val;
  84         int retval;
  85
  86         if (*offset)
  87                 return -EINVAL;
  88
  89         retval = oprofilefs_ulong_from_user(&val, buf, count);
  90         if (retval)
  91                 return retval;
  92
  93         if (val)
  94                 retval = oprofile_start();
  95         else
  96                 oprofile_stop();
  97
  98         if (retval)
  99                 return retval;
 100         return count;
 101 }
 102
 103
 104 static const struct file_operations enable_fops = {
 105         .read           = enable_read,
 106         .write          = enable_write,
 107 };
 108
 109
 110 static ssize_t dump_write(struct file * file, char const __user * buf, size_t count, loff_t * offset)
 111 {
 112         wake_up_buffer_waiter();
 113         return count;
 114 }
 115
 116
 117 static const struct file_operations dump_fops = {
 118         .write          = dump_write,
 119 };
 120
 121 void oprofile_create_files(struct super_block * sb, struct dentry * root)
 122 {
 123         oprofilefs_create_file(sb, root, "enable", &enable_fops);
 124         oprofilefs_create_file_perm(sb, root, "dump", &dump_fops, 0666);
 125         oprofilefs_create_file(sb, root, "buffer", &event_buffer_fops);
 126         oprofilefs_create_ulong(sb, root, "buffer_size", &fs_buffer_size);
 127         oprofilefs_create_ulong(sb, root, "buffer_watershed", &fs_buffer_watershed);
 128         oprofilefs_create_ulong(sb, root, "cpu_buffer_size", &fs_cpu_buffer_size);
 129         oprofilefs_create_file(sb, root, "cpu_type", &cpu_type_fops);
 130         oprofilefs_create_file(sb, root, "backtrace_depth", &depth_fops);
 131         oprofilefs_create_file(sb, root, "pointer_size", &pointer_size_fops);
 132         oprofile_create_stats_files(sb, root);
 133         if (oprofile_ops.create_files)
 134                 oprofile_ops.create_files(sb, root);
 135 }