arch/arm/kernel/atags.c

   1 #include <linux/slab.h>
   2 #include <linux/kexec.h>
   3 #include <linux/proc_fs.h>
   4 #include <asm/setup.h>
   5 #include <asm/types.h>
   6 #include <asm/page.h>
   7
   8 struct buffer {
   9         size_t size;
  10         char *data;
  11 };
  12 static struct buffer tags_buffer;
  13
  14 static int
  15 read_buffer(char* page, char** start, off_t off, int count,
  16         int* eof, void* data)
  17 {
  18         struct buffer *buffer = (struct buffer *)data;
  19
  20         if (off >= buffer->size) {
  21                 *eof = 1;
  22                 return 0;
  23         }
  24
  25         count = min((int) (buffer->size - off), count);
  26
  27         memcpy(page, &buffer->data[off], count);
  28
  29         return count;
  30 }
  31
  32
  33 static int
  34 create_proc_entries(void)
  35 {
  36         struct proc_dir_entry* tags_entry;
  37
  38         tags_entry = create_proc_read_entry("atags", 0400, &proc_root, read_buffer, &tags_buffer);
  39         if (!tags_entry)
  40                 return -ENOMEM;
  41
  42         return 0;
  43 }
  44
  45
  46 static char __initdata atags_copy_buf[KEXEC_BOOT_PARAMS_SIZE];
  47 static char __initdata *atags_copy;
  48
  49 void __init save_atags(const struct tag *tags)
  50 {
  51         atags_copy = atags_copy_buf;
  52         memcpy(atags_copy, tags, KEXEC_BOOT_PARAMS_SIZE);
  53 }
  54
  55
  56 static int __init init_atags_procfs(void)
  57 {
  58         struct tag *tag;
  59         int error;
  60
  61         if (!atags_copy) {
  62                 printk(KERN_WARNING "Exporting ATAGs: No saved tags found\n");
  63                 return -EIO;
  64         }
  65
  66         for (tag = (struct tag *) atags_copy; tag->hdr.size; tag = tag_next(tag))
  67                 ;
  68
  69         tags_buffer.size = ((char *) tag - atags_copy) + sizeof(tag->hdr);
  70         tags_buffer.data = kmalloc(tags_buffer.size, GFP_KERNEL);
  71         if (tags_buffer.data == NULL)
  72                 return -ENOMEM;
  73         memcpy(tags_buffer.data, atags_copy, tags_buffer.size);
  74
  75         error = create_proc_entries();
  76         if (error) {
  77                 printk(KERN_ERR "Exporting ATAGs: not enough memory\n");
  78                 kfree(tags_buffer.data);
  79                 tags_buffer.size = 0;
  80                 tags_buffer.data = NULL;
  81         }
  82
  83         return error;
  84 }
  85
  86 arch_initcall(init_atags_procfs);