xref: /openbmc/linux/kernel/configs.c (revision ae213c44)
1 /*
2  * kernel/configs.c
3  * Echo the kernel .config file used to build the kernel
4  *
5  * Copyright (C) 2002 Khalid Aziz <khalid_aziz@hp.com>
6  * Copyright (C) 2002 Randy Dunlap <rdunlap@xenotime.net>
7  * Copyright (C) 2002 Al Stone <ahs3@fc.hp.com>
8  * Copyright (C) 2002 Hewlett-Packard Company
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or (at
13  * your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful, but
16  * WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
18  * NON INFRINGEMENT.  See the GNU General Public License for more
19  * details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, write to the Free Software
23  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24  */
25 
26 #include <linux/kernel.h>
27 #include <linux/module.h>
28 #include <linux/proc_fs.h>
29 #include <linux/seq_file.h>
30 #include <linux/init.h>
31 #include <linux/uaccess.h>
32 
33 /*
34  * "IKCFG_ST" and "IKCFG_ED" are used to extract the config data from
35  * a binary kernel image or a module. See scripts/extract-ikconfig.
36  */
37 asm (
38 "	.pushsection .rodata, \"a\"		\n"
39 "	.ascii \"IKCFG_ST\"			\n"
40 "	.global kernel_config_data		\n"
41 "kernel_config_data:				\n"
42 "	.incbin \"kernel/config_data.gz\"	\n"
43 "	.global kernel_config_data_end		\n"
44 "kernel_config_data_end:			\n"
45 "	.ascii \"IKCFG_ED\"			\n"
46 "	.popsection				\n"
47 );
48 
49 #ifdef CONFIG_IKCONFIG_PROC
50 
51 extern char kernel_config_data;
52 extern char kernel_config_data_end;
53 
54 static ssize_t
55 ikconfig_read_current(struct file *file, char __user *buf,
56 		      size_t len, loff_t * offset)
57 {
58 	return simple_read_from_buffer(buf, len, offset,
59 				       &kernel_config_data,
60 				       &kernel_config_data_end -
61 				       &kernel_config_data);
62 }
63 
64 static const struct file_operations ikconfig_file_ops = {
65 	.owner = THIS_MODULE,
66 	.read = ikconfig_read_current,
67 	.llseek = default_llseek,
68 };
69 
70 static int __init ikconfig_init(void)
71 {
72 	struct proc_dir_entry *entry;
73 
74 	/* create the current config file */
75 	entry = proc_create("config.gz", S_IFREG | S_IRUGO, NULL,
76 			    &ikconfig_file_ops);
77 	if (!entry)
78 		return -ENOMEM;
79 
80 	proc_set_size(entry, &kernel_config_data_end - &kernel_config_data);
81 
82 	return 0;
83 }
84 
85 static void __exit ikconfig_cleanup(void)
86 {
87 	remove_proc_entry("config.gz", NULL);
88 }
89 
90 module_init(ikconfig_init);
91 module_exit(ikconfig_cleanup);
92 
93 #endif /* CONFIG_IKCONFIG_PROC */
94 
95 MODULE_LICENSE("GPL");
96 MODULE_AUTHOR("Randy Dunlap");
97 MODULE_DESCRIPTION("Echo the kernel .config file used to build the kernel");
98