arch/x86/xen/debugfs.c

   1 #include <linux/init.h>
   2 #include <linux/debugfs.h>
   3 #include <linux/slab.h>
   4 #include <linux/module.h>
   5
   6 #include "debugfs.h"
   7
   8 static struct dentry *d_xen_debug;
   9
  10 struct dentry * __init xen_init_debugfs(void)
  11 {
  12         if (!d_xen_debug) {
  13                 d_xen_debug = debugfs_create_dir("xen", NULL);
  14
  15                 if (!d_xen_debug)
  16                         pr_warning("Could not create 'xen' debugfs directory\n");
  17         }
  18
  19         return d_xen_debug;
  20 }
  21
  22 struct array_data
  23 {
  24         void *array;
  25         unsigned elements;
  26 };
  27
  28 static int u32_array_open(struct inode *inode, struct file *file)
  29 {
  30         file->private_data = NULL;
  31         return nonseekable_open(inode, file);
  32 }
  33
  34 static size_t format_array(char *buf, size_t bufsize, const char *fmt,
  35                            u32 *array, unsigned array_size)
  36 {
  37         size_t ret = 0;
  38         unsigned i;
  39
  40         for(i = 0; i < array_size; i++) {
  41                 size_t len;
  42
  43                 len = snprintf(buf, bufsize, fmt, array[i]);
  44                 len++;  /* ' ' or '\n' */
  45                 ret += len;
  46
  47                 if (buf) {
  48                         buf += len;
  49                         bufsize -= len;
  50                         buf[-1] = (i == array_size-1) ? '\n' : ' ';
  51                 }
  52         }
  53
  54         ret++;          /* \0 */
  55         if (buf)
  56                 *buf = '\0';
  57
  58         return ret;
  59 }
  60
  61 static char *format_array_alloc(const char *fmt, u32 *array, unsigned array_size)
  62 {
  63         size_t len = format_array(NULL, 0, fmt, array, array_size);
  64         char *ret;
  65
  66         ret = kmalloc(len, GFP_KERNEL);
  67         if (ret == NULL)
  68                 return NULL;
  69
  70         format_array(ret, len, fmt, array, array_size);
  71         return ret;
  72 }
  73
  74 static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len,
  75                               loff_t *ppos)
  76 {
  77         struct inode *inode = file->f_path.dentry->d_inode;
  78         struct array_data *data = inode->i_private;
  79         size_t size;
  80
  81         if (*ppos == 0) {
  82                 if (file->private_data) {
  83                         kfree(file->private_data);
  84                         file->private_data = NULL;
  85                 }
  86
  87                 file->private_data = format_array_alloc("%u", data->array, data->elements);
  88         }
  89
  90         size = 0;
  91         if (file->private_data)
  92                 size = strlen(file->private_data);
  93
  94         return simple_read_from_buffer(buf, len, ppos, file->private_data, size);
  95 }
  96
  97 static int xen_array_release(struct inode *inode, struct file *file)
  98 {
  99         kfree(file->private_data);
 100
 101         return 0;
 102 }
 103
 104 static const struct file_operations u32_array_fops = {
 105         .owner  = THIS_MODULE,
 106         .open   = u32_array_open,
 107         .release= xen_array_release,
 108         .read   = u32_array_read,
 109         .llseek = no_llseek,
 110 };
 111
 112 struct dentry *xen_debugfs_create_u32_array(const char *name, mode_t mode,
 113                                             struct dentry *parent,
 114                                             u32 *array, unsigned elements)
 115 {
 116         struct array_data *data = kmalloc(sizeof(*data), GFP_KERNEL);
 117
 118         if (data == NULL)
 119                 return NULL;
 120
 121         data->array = array;
 122         data->elements = elements;
 123
 124         return debugfs_create_file(name, mode, parent, data, &u32_array_fops);
 125 }