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
7 struct buffer {
8 size_t size;
9 char data[];
10 };
11
12 static int
read_buffer(char * page,char ** start,off_t off,int count,int * eof,void * data)13 read_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
31 static char __initdata atags_copy[BOOT_PARAMS_SIZE];
32
save_atags(const struct tag * tags)33 void __init save_atags(const struct tag *tags)
34 {
35 memcpy(atags_copy, tags, sizeof(atags_copy));
36 }
37
init_atags_procfs(void)38 static 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
77 nomem:
78 kfree(b);
79 printk(KERN_ERR "Exporting ATAGs: not enough memory\n");
80
81 return -ENOMEM;
82 }
83 arch_initcall(init_atags_procfs);
84