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
17static char bootinfo_tmp[1536] __initdata;
18
19static void *bootinfo_copy;
20static size_t bootinfo_size;
21
22static ssize_t bootinfo_read(struct file *file, char __user *buf,
23 size_t count, loff_t *ppos)
24{
25 return simple_read_from_buffer(to: buf, count, ppos, from: bootinfo_copy,
26 available: bootinfo_size);
27}
28
29static const struct proc_ops bootinfo_proc_ops = {
30 .proc_read = bootinfo_read,
31 .proc_lseek = default_llseek,
32};
33
34void __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
55static 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(p: bootinfo_tmp, size: 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(objp: bootinfo_copy);
73 return -ENOMEM;
74 }
75
76 return 0;
77}
78
79arch_initcall(init_bootinfo_procfs);
80

source code of linux/arch/m68k/kernel/bootinfo_proc.c