xref: /openbmc/linux/arch/m68k/kernel/bootinfo_proc.c (revision 97a32539)
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