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 #define FS_BUFFER_SIZE_DEFAULT          131072
  18 #define FS_CPU_BUFFER_SIZE_DEFAULT      8192
  19 #define FS_BUFFER_WATERSHED_DEFAULT     32768   /* FIXME: tune */
  20
  21 unsigned long fs_buffer_size;
  22 unsigned long fs_cpu_buffer_size;
  23 unsigned long fs_buffer_watershed;
  24
  25 static ssize_t depth_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
  26 {
  27         return oprofilefs_ulong_to_user(backtrace_depth, buf, count, offset);
  28 }
  29
  30
  31 static ssize_t depth_write(struct file *file, char const __user *buf, size_t count, loff_t *offset)
  32 {
  33         unsigned long val;
  34         int retval;
  35
  36         if (*offset)
  37                 return -EINVAL;
  38
  39         retval = oprofilefs_ulong_from_user(&val, buf, count);
  40         if (retval)
  41                 return retval;
  42
  43         retval = oprofile_set_backtrace(val);
  44
  45         if (retval)
  46                 return retval;
  47         return count;
  48 }
  49
  50
  51 static const struct file_operations depth_fops = {
  52         .read           = depth_read,
  53         .write          = depth_write
  54 };
  55
  56
  57 static ssize_t pointer_size_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
  58 {
  59         return oprofilefs_ulong_to_user(sizeof(void *), buf, count, offset);
  60 }
  61
  62
  63 static const struct file_operations pointer_size_fops = {
  64         .read           = pointer_size_read,
  65 };
  66
  67
  68 static ssize_t cpu_type_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
  69 {
  70         return oprofilefs_str_to_user(oprofile_ops.cpu_type, buf, count, offset);
  71 }
  72
  73
  74 static const struct file_operations cpu_type_fops = {
  75         .read           = cpu_type_read,
  76 };
  77
  78
  79 static ssize_t enable_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
  80 {
  81         return oprofilefs_ulong_to_user(oprofile_started, buf, count, offset);
  82 }
  83
  84
  85 static ssize_t enable_write(struct file *file, char const __user *buf, size_t count, loff_t *offset)
  86 {
  87         unsigned long val;
  88         int retval;
  89
  90         if (*offset)
  91                 return -EINVAL;
  92
  93         retval = oprofilefs_ulong_from_user(&val, buf, count);
  94         if (retval)
  95                 return retval;
  96
  97         if (val)
  98                 retval = oprofile_start();
  99         else
 100                 oprofile_stop();
 101
 102         if (retval)
 103                 return retval;
 104         return count;
 105 }
 106
 107
 108 static const struct file_operations enable_fops = {
 109         .read           = enable_read,
 110         .write          = enable_write,
 111 };
 112
 113
 114 static ssize_t dump_write(struct file *file, char const __user *buf, size_t count, loff_t *offset)
 115 {
 116         wake_up_buffer_waiter();
 117         return count;
 118 }
 119
 120
 121 static const struct file_operations dump_fops = {
 122         .write          = dump_write,
 123 };
 124
 125 void oprofile_create_files(struct super_block *sb, struct dentry *root)
 126 {
 127         /* reinitialize default values */
 128         fs_buffer_size =        FS_BUFFER_SIZE_DEFAULT;
 129         fs_cpu_buffer_size =    FS_CPU_BUFFER_SIZE_DEFAULT;
 130         fs_buffer_watershed =   FS_BUFFER_WATERSHED_DEFAULT;
 131
 132         oprofilefs_create_file(sb, root, "enable", &enable_fops);
 133         oprofilefs_create_file_perm(sb, root, "dump", &dump_fops, 0666);
 134         oprofilefs_create_file(sb, root, "buffer", &event_buffer_fops);
 135         oprofilefs_create_ulong(sb, root, "buffer_size", &fs_buffer_size);
 136         oprofilefs_create_ulong(sb, root, "buffer_watershed", &fs_buffer_watershed);
 137         oprofilefs_create_ulong(sb, root, "cpu_buffer_size", &fs_cpu_buffer_size);
 138         oprofilefs_create_file(sb, root, "cpu_type", &cpu_type_fops);
 139         oprofilefs_create_file(sb, root, "backtrace_depth", &depth_fops);
 140         oprofilefs_create_file(sb, root, "pointer_size", &pointer_size_fops);
 141         oprofile_create_stats_files(sb, root);
 142         if (oprofile_ops.create_files)
 143                 oprofile_ops.create_files(sb, root);
 144 }