1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Based on arch/arm/kernel/atags_proc.c
4 */
5
6 #include <linux/fs.h>
7 #include <linux/init.h>
8 #include <linux/printk.h>
9 #include <linux/proc_fs.h>
10 #include <linux/slab.h>
11 #include <linux/string.h>
12
13 #include <asm/bootinfo.h>
14 #include <asm/byteorder.h>
15
16
17 static char bootinfo_tmp[1536] __initdata;
18
19 static void *bootinfo_copy;
20 static size_t bootinfo_size;
21
bootinfo_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)22 static ssize_t bootinfo_read(struct file *file, char __user *buf,
23 size_t count, loff_t *ppos)
24 {
25 return simple_read_from_buffer(buf, count, ppos, bootinfo_copy,
26 bootinfo_size);
27 }
28
29 static const struct proc_ops bootinfo_proc_ops = {
30 .proc_read = bootinfo_read,
31 .proc_lseek = default_llseek,
32 };
33
save_bootinfo(const struct bi_record * bi)34 void __init save_bootinfo(const struct bi_record *bi)
35 {
36 const void *start = bi;
37 size_t size = sizeof(bi->tag);
38
39 while (be16_to_cpu(bi->tag) != BI_LAST) {
40 uint16_t n = be16_to_cpu(bi->size);
41 size += n;
42 bi = (struct bi_record *)((unsigned long)bi + n);
43 }
44
45 if (size > sizeof(bootinfo_tmp)) {
46 pr_err("Cannot save %zu bytes of bootinfo\n", size);
47 return;
48 }
49
50 pr_info("Saving %zu bytes of bootinfo\n", size);
51 memcpy(bootinfo_tmp, start, size);
52 bootinfo_size = size;
53 }
54
init_bootinfo_procfs(void)55 static int __init init_bootinfo_procfs(void)
56 {
57 /*
58 * This cannot go into save_bootinfo() because kmalloc and proc don't
59 * work yet when it is called.
60 */
61 struct proc_dir_entry *pde;
62
63 if (!bootinfo_size)
64 return -EINVAL;
65
66 bootinfo_copy = kmemdup(bootinfo_tmp, bootinfo_size, GFP_KERNEL);
67 if (!bootinfo_copy)
68 return -ENOMEM;
69
70 pde = proc_create_data("bootinfo", 0400, NULL, &bootinfo_proc_ops, NULL);
71 if (!pde) {
72 kfree(bootinfo_copy);
73 return -ENOMEM;
74 }
75
76 return 0;
77 }
78
79 arch_initcall(init_bootinfo_procfs);
80