Merge tag 'for-5.16/block-2021-11-09' of git://git.kernel.dk/linux-block
[linux-2.6-microblaze.git] / kernel / configs.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * kernel/configs.c
4  * Echo the kernel .config file used to build the kernel
5  *
6  * Copyright (C) 2002 Khalid Aziz <khalid_aziz@hp.com>
7  * Copyright (C) 2002 Randy Dunlap <rdunlap@xenotime.net>
8  * Copyright (C) 2002 Al Stone <ahs3@fc.hp.com>
9  * Copyright (C) 2002 Hewlett-Packard Company
10  */
11
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/proc_fs.h>
15 #include <linux/seq_file.h>
16 #include <linux/init.h>
17 #include <linux/uaccess.h>
18
19 /*
20  * "IKCFG_ST" and "IKCFG_ED" are used to extract the config data from
21  * a binary kernel image or a module. See scripts/extract-ikconfig.
22  */
23 asm (
24 "       .pushsection .rodata, \"a\"             \n"
25 "       .ascii \"IKCFG_ST\"                     \n"
26 "       .global kernel_config_data              \n"
27 "kernel_config_data:                            \n"
28 "       .incbin \"kernel/config_data.gz\"       \n"
29 "       .global kernel_config_data_end          \n"
30 "kernel_config_data_end:                        \n"
31 "       .ascii \"IKCFG_ED\"                     \n"
32 "       .popsection                             \n"
33 );
34
35 #ifdef CONFIG_IKCONFIG_PROC
36
37 extern char kernel_config_data;
38 extern char kernel_config_data_end;
39
40 static ssize_t
41 ikconfig_read_current(struct file *file, char __user *buf,
42                       size_t len, loff_t * offset)
43 {
44         return simple_read_from_buffer(buf, len, offset,
45                                        &kernel_config_data,
46                                        &kernel_config_data_end -
47                                        &kernel_config_data);
48 }
49
50 static const struct proc_ops config_gz_proc_ops = {
51         .proc_read      = ikconfig_read_current,
52         .proc_lseek     = default_llseek,
53 };
54
55 static int __init ikconfig_init(void)
56 {
57         struct proc_dir_entry *entry;
58
59         /* create the current config file */
60         entry = proc_create("config.gz", S_IFREG | S_IRUGO, NULL,
61                             &config_gz_proc_ops);
62         if (!entry)
63                 return -ENOMEM;
64
65         proc_set_size(entry, &kernel_config_data_end - &kernel_config_data);
66
67         return 0;
68 }
69
70 static void __exit ikconfig_cleanup(void)
71 {
72         remove_proc_entry("config.gz", NULL);
73 }
74
75 module_init(ikconfig_init);
76 module_exit(ikconfig_cleanup);
77
78 #endif /* CONFIG_IKCONFIG_PROC */
79
80 MODULE_LICENSE("GPL");
81 MODULE_AUTHOR("Randy Dunlap");
82 MODULE_DESCRIPTION("Echo the kernel .config file used to build the kernel");