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 BUFFER_SIZE_DEFAULT             131072
  18 #define CPU_BUFFER_SIZE_DEFAULT         8192
  19 #define BUFFER_WATERSHED_DEFAULT        32768   /* FIXME: tune */
  20
  21 unsigned long oprofile_buffer_size;
  22 unsigned long oprofile_cpu_buffer_size;
  23 unsigned long oprofile_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(oprofile_backtrace_depth, buf, count,
  28                                         offset);
  29 }
  30
  31
  32 static ssize_t depth_write(struct file *file, char const __user *buf, size_t count, loff_t *offset)
  33 {
  34         unsigned long val;
  35         int retval;
  36
  37         if (*offset)
  38                 return -EINVAL;
  39
  40         retval = oprofilefs_ulong_from_user(&val, buf, count);
  41         if (retval)
  42                 return retval;
  43
  44         retval = oprofile_set_backtrace(val);
  45
  46         if (retval)
  47                 return retval;
  48         return count;
  49 }
  50
  51
  52 static const struct file_operations depth_fops = {
  53         .read           = depth_read,
  54         .write          = depth_write
  55 };
  56
  57
  58 static ssize_t pointer_size_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
  59 {
  60         return oprofilefs_ulong_to_user(sizeof(void *), buf, count, offset);
  61 }
  62
  63
  64 static const struct file_operations pointer_size_fops = {
  65         .read           = pointer_size_read,
  66 };
  67
  68
  69 static ssize_t cpu_type_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
  70 {
  71         return oprofilefs_str_to_user(oprofile_ops.cpu_type, buf, count, offset);
  72 }
  73
  74
  75 static const struct file_operations cpu_type_fops = {
  76         .read           = cpu_type_read,
  77 };
  78
  79
  80 static ssize_t enable_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
  81 {
  82         return oprofilefs_ulong_to_user(oprofile_started, buf, count, offset);
  83 }
  84
  85
  86 static ssize_t enable_write(struct file *file, char const __user *buf, size_t count, loff_t *offset)
  87 {
  88         unsigned long val;
  89         int retval;
  90
  91         if (*offset)
  92                 return -EINVAL;
  93
  94         retval = oprofilefs_ulong_from_user(&val, buf, count);
  95         if (retval)
  96                 return retval;
  97
  98         if (val)
  99                 retval = oprofile_start();
 100         else
 101                 oprofile_stop();
 102
 103         if (retval)
 104                 return retval;
 105         return count;
 106 }
 107
 108
 109 static const struct file_operations enable_fops = {
 110         .read           = enable_read,
 111         .write          = enable_write,
 112 };
 113
 114
 115 static ssize_t dump_write(struct file *file, char const __user *buf, size_t count, loff_t *offset)
 116 {
 117         wake_up_buffer_waiter();
 118         return count;
 119 }
 120
 121
 122 static const struct file_operations dump_fops = {
 123         .write          = dump_write,
 124 };
 125
 126 void oprofile_create_files(struct super_block *sb, struct dentry *root)
 127 {
 128         /* reinitialize default values */
 129         oprofile_buffer_size =          BUFFER_SIZE_DEFAULT;
 130         oprofile_cpu_buffer_size =      CPU_BUFFER_SIZE_DEFAULT;
 131         oprofile_buffer_watershed =     BUFFER_WATERSHED_DEFAULT;
 132
 133         oprofilefs_create_file(sb, root, "enable", &enable_fops);
 134         oprofilefs_create_file_perm(sb, root, "dump", &dump_fops, 0666);
 135         oprofilefs_create_file(sb, root, "buffer", &event_buffer_fops);
 136         oprofilefs_create_ulong(sb, root, "buffer_size", &oprofile_buffer_size);
 137         oprofilefs_create_ulong(sb, root, "buffer_watershed", &oprofile_buffer_watershed);
 138         oprofilefs_create_ulong(sb, root, "cpu_buffer_size", &oprofile_cpu_buffer_size);
 139         oprofilefs_create_file(sb, root, "cpu_type", &cpu_type_fops);
 140         oprofilefs_create_file(sb, root, "backtrace_depth", &depth_fops);
 141         oprofilefs_create_file(sb, root, "pointer_size", &pointer_size_fops);
 142         oprofile_create_stats_files(sb, root);
 143         if (oprofile_ops.create_files)
 144                 oprofile_ops.create_files(sb, root);
 145 }