LXR linux/arch/arm/kernel/atags

   1#include <linux/slab.h>
   2#include <linux/proc_fs.h>
   3#include <asm/setup.h>
   4#include <asm/types.h>
   5#include <asm/page.h>
   6
   7struct buffer {
   8        size_t size;
   9        char data[];
  10};
  11
  12static int
  13read_buffer(char* page, char** start, off_t off, int count,
  14        int* eof, void* data)
  15{
  16        struct buffer *buffer = (struct buffer *)data;
  17
  18        if (off >= buffer->size) {
  19                *eof = 1;
  20                return 0;
  21        }
  22
  23        count = min((int) (buffer->size - off), count);
  24
  25        memcpy(page, &buffer->data[off], count);
  26
  27        return count;
  28}
  29
  30#define BOOT_PARAMS_SIZE 1536
  31static char __initdata atags_copy[BOOT_PARAMS_SIZE];
  32
  33void __init save_atags(const struct tag *tags)
  34{
  35        memcpy(atags_copy, tags, sizeof(atags_copy));
  36}
  37
  38static int __init init_atags_procfs(void)
  39{
  40        /*
  41         * This cannot go into save_atags() because kmalloc and proc don't work
  42         * yet when it is called.
  43         */
  44        struct proc_dir_entry *tags_entry;
  45        struct tag *tag = (struct tag *)atags_copy;
  46        struct buffer *b;
  47        size_t size;
  48
  49        if (tag->hdr.tag != ATAG_CORE) {
  50                printk(KERN_INFO "No ATAGs?");
  51                return -EINVAL;
  52        }
  53
  54        for (; tag->hdr.size; tag = tag_next(tag))
  55                ;
  56
  57        /* include the terminating ATAG_NONE */
  58        size = (char *)tag - atags_copy + sizeof(struct tag_header);
  59
  60        WARN_ON(tag->hdr.tag != ATAG_NONE);
  61
  62        b = kmalloc(sizeof(*b) + size, GFP_KERNEL);
  63        if (!b)
  64                goto nomem;
  65
  66        b->size = size;
  67        memcpy(b->data, atags_copy, size);
  68
  69        tags_entry = create_proc_read_entry("atags", 0400,
  70                        NULL, read_buffer, b);
  71
  72        if (!tags_entry)
  73                goto nomem;
  74
  75        return 0;
  76
  77nomem:
  78        kfree(b);
  79        printk(KERN_ERR "Exporting ATAGs: not enough memory\n");
  80
  81        return -ENOMEM;
  82}
  83arch_initcall(init_atags_procfs);
  84