blob: b1292a57c2a5326462e83180ba2aaad677270a79 [file] [log] [blame]
Thomas Gleixner468e15f2019-05-27 08:55:17 +02001// SPDX-License-Identifier: GPL-2.0-only
Linus Torvalds1da177e2005-04-16 15:20:36 -07002/*
3 * kernel/ksysfs.c - sysfs attributes in /sys/kernel, which
4 * are not related to any other subsystem
5 *
6 * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 */
8
Linus Torvalds1da177e2005-04-16 15:20:36 -07009#include <linux/kobject.h>
10#include <linux/string.h>
11#include <linux/sysfs.h>
Paul Gortmaker9984de12011-05-23 14:51:41 -040012#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070013#include <linux/init.h>
Jeff Moyerc330dda2006-06-23 02:05:07 -070014#include <linux/kexec.h>
Dave Hansen22b8ce92008-10-15 22:01:46 -070015#include <linux/profile.h>
Paul Gortmaker15964252011-07-28 14:22:29 -040016#include <linux/stat.h>
Dhaval Giani5cb350b2007-10-15 17:00:14 +020017#include <linux/sched.h>
Ludwig Nussel088ab0b2011-02-28 15:57:17 +010018#include <linux/capability.h>
Gideon Israel Dsouza52f5684c2014-04-07 15:39:20 -070019#include <linux/compiler.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020
Paul E. McKenney5a9be7c2015-11-24 15:44:06 -080021#include <linux/rcupdate.h> /* rcu_expedited and rcu_normal */
Paul Gortmaker7a754742014-02-11 16:10:12 -050022
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#define KERNEL_ATTR_RO(_name) \
Kay Sievers386f2752007-11-02 13:47:53 +010024static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
Linus Torvalds1da177e2005-04-16 15:20:36 -070025
26#define KERNEL_ATTR_RW(_name) \
Miaohe Lina7cd9a52022-03-23 16:05:35 -070027static struct kobj_attribute _name##_attr = __ATTR_RW(_name)
Linus Torvalds1da177e2005-04-16 15:20:36 -070028
Kay Sievers0f76e5a2005-11-11 04:58:04 +010029/* current uevent sequence number */
Kay Sievers386f2752007-11-02 13:47:53 +010030static ssize_t uevent_seqnum_show(struct kobject *kobj,
31 struct kobj_attribute *attr, char *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -070032{
Kay Sievers386f2752007-11-02 13:47:53 +010033 return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum);
Linus Torvalds1da177e2005-04-16 15:20:36 -070034}
Kay Sievers0f76e5a2005-11-11 04:58:04 +010035KERNEL_ATTR_RO(uevent_seqnum);
36
Michael Marineau86d56132014-04-10 14:09:31 -070037#ifdef CONFIG_UEVENT_HELPER
Thadeu Lima de Souza Cascardoaf665852010-01-17 19:14:26 -020038/* uevent helper program, used during early boot */
Kay Sievers386f2752007-11-02 13:47:53 +010039static ssize_t uevent_helper_show(struct kobject *kobj,
40 struct kobj_attribute *attr, char *buf)
Kay Sievers0f76e5a2005-11-11 04:58:04 +010041{
Kay Sievers386f2752007-11-02 13:47:53 +010042 return sprintf(buf, "%s\n", uevent_helper);
Kay Sievers0f76e5a2005-11-11 04:58:04 +010043}
Kay Sievers386f2752007-11-02 13:47:53 +010044static ssize_t uevent_helper_store(struct kobject *kobj,
45 struct kobj_attribute *attr,
46 const char *buf, size_t count)
Kay Sievers0f76e5a2005-11-11 04:58:04 +010047{
Kay Sievers312c0042005-11-16 09:00:00 +010048 if (count+1 > UEVENT_HELPER_PATH_LEN)
Kay Sievers0f76e5a2005-11-11 04:58:04 +010049 return -ENOENT;
Kay Sievers386f2752007-11-02 13:47:53 +010050 memcpy(uevent_helper, buf, count);
Kay Sievers312c0042005-11-16 09:00:00 +010051 uevent_helper[count] = '\0';
52 if (count && uevent_helper[count-1] == '\n')
53 uevent_helper[count-1] = '\0';
Kay Sievers0f76e5a2005-11-11 04:58:04 +010054 return count;
55}
56KERNEL_ATTR_RW(uevent_helper);
Michael Marineau86d56132014-04-10 14:09:31 -070057#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070058
Dave Hansen22b8ce92008-10-15 22:01:46 -070059#ifdef CONFIG_PROFILING
60static ssize_t profiling_show(struct kobject *kobj,
61 struct kobj_attribute *attr, char *buf)
62{
63 return sprintf(buf, "%d\n", prof_on);
64}
65static ssize_t profiling_store(struct kobject *kobj,
66 struct kobj_attribute *attr,
67 const char *buf, size_t count)
68{
69 int ret;
70
71 if (prof_on)
72 return -EEXIST;
73 /*
74 * This eventually calls into get_option() which
75 * has a ton of callers and is not const. It is
76 * easiest to cast it away here.
77 */
78 profile_setup((char *)buf);
79 ret = profile_init();
80 if (ret)
81 return ret;
82 ret = create_proc_profile();
83 if (ret)
84 return ret;
85 return count;
86}
87KERNEL_ATTR_RW(profiling);
88#endif
89
Dave Young2965faa2015-09-09 15:38:55 -070090#ifdef CONFIG_KEXEC_CORE
Kay Sievers386f2752007-11-02 13:47:53 +010091static ssize_t kexec_loaded_show(struct kobject *kobj,
92 struct kobj_attribute *attr, char *buf)
Jeff Moyerc330dda2006-06-23 02:05:07 -070093{
Kay Sievers386f2752007-11-02 13:47:53 +010094 return sprintf(buf, "%d\n", !!kexec_image);
Jeff Moyerc330dda2006-06-23 02:05:07 -070095}
96KERNEL_ATTR_RO(kexec_loaded);
97
Kay Sievers386f2752007-11-02 13:47:53 +010098static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
99 struct kobj_attribute *attr, char *buf)
Jeff Moyerc330dda2006-06-23 02:05:07 -0700100{
Petr Tesarik21db79e2016-08-02 14:06:16 -0700101 return sprintf(buf, "%d\n", kexec_crash_loaded());
Jeff Moyerc330dda2006-06-23 02:05:07 -0700102}
103KERNEL_ATTR_RO(kexec_crash_loaded);
Ken'ichi Ohmichifd59d232007-10-16 23:27:27 -0700104
Amerigo Wang06a7f712009-12-15 16:47:46 -0800105static ssize_t kexec_crash_size_show(struct kobject *kobj,
106 struct kobj_attribute *attr, char *buf)
107{
108 return sprintf(buf, "%zu\n", crash_get_memory_size());
109}
110static ssize_t kexec_crash_size_store(struct kobject *kobj,
111 struct kobj_attribute *attr,
112 const char *buf, size_t count)
113{
114 unsigned long cnt;
115 int ret;
116
Jingoo Han6072ddc2013-09-12 15:14:07 -0700117 if (kstrtoul(buf, 0, &cnt))
Amerigo Wang06a7f712009-12-15 16:47:46 -0800118 return -EINVAL;
119
120 ret = crash_shrink_memory(cnt);
121 return ret < 0 ? ret : count;
122}
123KERNEL_ATTR_RW(kexec_crash_size);
124
Hari Bathini692f66f2017-05-08 15:56:18 -0700125#endif /* CONFIG_KEXEC_CORE */
126
127#ifdef CONFIG_CRASH_CORE
128
Kay Sievers386f2752007-11-02 13:47:53 +0100129static ssize_t vmcoreinfo_show(struct kobject *kobj,
130 struct kobj_attribute *attr, char *buf)
Ken'ichi Ohmichifd59d232007-10-16 23:27:27 -0700131{
Russell Kingdae28012016-08-02 14:06:00 -0700132 phys_addr_t vmcore_base = paddr_vmcoreinfo_note();
133 return sprintf(buf, "%pa %x\n", &vmcore_base,
Xunlei Pang203e9e42017-07-12 14:33:14 -0700134 (unsigned int)VMCOREINFO_NOTE_SIZE);
Ken'ichi Ohmichifd59d232007-10-16 23:27:27 -0700135}
136KERNEL_ATTR_RO(vmcoreinfo);
137
Hari Bathini692f66f2017-05-08 15:56:18 -0700138#endif /* CONFIG_CRASH_CORE */
Jeff Moyerc330dda2006-06-23 02:05:07 -0700139
Ludwig Nussel088ab0b2011-02-28 15:57:17 +0100140/* whether file capabilities are enabled */
141static ssize_t fscaps_show(struct kobject *kobj,
142 struct kobj_attribute *attr, char *buf)
143{
144 return sprintf(buf, "%d\n", file_caps_enabled);
145}
146KERNEL_ATTR_RO(fscaps);
147
Paul E. McKenney79cfea022015-12-07 13:09:52 -0800148#ifndef CONFIG_TINY_RCU
Antti P Miettinen3705b882012-10-05 09:59:15 +0300149int rcu_expedited;
150static ssize_t rcu_expedited_show(struct kobject *kobj,
151 struct kobj_attribute *attr, char *buf)
152{
Paul E. McKenney5a9be7c2015-11-24 15:44:06 -0800153 return sprintf(buf, "%d\n", READ_ONCE(rcu_expedited));
Antti P Miettinen3705b882012-10-05 09:59:15 +0300154}
155static ssize_t rcu_expedited_store(struct kobject *kobj,
156 struct kobj_attribute *attr,
157 const char *buf, size_t count)
158{
159 if (kstrtoint(buf, 0, &rcu_expedited))
160 return -EINVAL;
161
162 return count;
163}
164KERNEL_ATTR_RW(rcu_expedited);
165
Paul E. McKenney5a9be7c2015-11-24 15:44:06 -0800166int rcu_normal;
167static ssize_t rcu_normal_show(struct kobject *kobj,
168 struct kobj_attribute *attr, char *buf)
169{
170 return sprintf(buf, "%d\n", READ_ONCE(rcu_normal));
171}
172static ssize_t rcu_normal_store(struct kobject *kobj,
173 struct kobj_attribute *attr,
174 const char *buf, size_t count)
175{
176 if (kstrtoint(buf, 0, &rcu_normal))
177 return -EINVAL;
178
179 return count;
180}
181KERNEL_ATTR_RW(rcu_normal);
Paul E. McKenney79cfea022015-12-07 13:09:52 -0800182#endif /* #ifndef CONFIG_TINY_RCU */
Paul E. McKenney5a9be7c2015-11-24 15:44:06 -0800183
Roland McGrathda1a6792007-07-19 01:48:39 -0700184/*
185 * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
186 */
Gideon Israel Dsouza52f5684c2014-04-07 15:39:20 -0700187extern const void __start_notes __weak;
188extern const void __stop_notes __weak;
Roland McGrathda1a6792007-07-19 01:48:39 -0700189#define notes_size (&__stop_notes - &__start_notes)
190
Chris Wright2c3c8be2010-05-12 18:28:57 -0700191static ssize_t notes_read(struct file *filp, struct kobject *kobj,
192 struct bin_attribute *bin_attr,
Roland McGrathda1a6792007-07-19 01:48:39 -0700193 char *buf, loff_t off, size_t count)
194{
195 memcpy(buf, &__start_notes + off, count);
196 return count;
197}
198
Bhumika Goyal738bc382017-02-24 15:00:46 -0800199static struct bin_attribute notes_attr __ro_after_init = {
Roland McGrathda1a6792007-07-19 01:48:39 -0700200 .attr = {
201 .name = "notes",
202 .mode = S_IRUGO,
203 },
204 .read = &notes_read,
205};
206
Greg Kroah-Hartman0ff21e42007-11-06 10:36:58 -0800207struct kobject *kernel_kobj;
208EXPORT_SYMBOL_GPL(kernel_kobj);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209
210static struct attribute * kernel_attrs[] = {
Ludwig Nussel088ab0b2011-02-28 15:57:17 +0100211 &fscaps_attr.attr,
Kay Sievers0f76e5a2005-11-11 04:58:04 +0100212 &uevent_seqnum_attr.attr,
Michael Marineau86d56132014-04-10 14:09:31 -0700213#ifdef CONFIG_UEVENT_HELPER
Kay Sievers0f76e5a2005-11-11 04:58:04 +0100214 &uevent_helper_attr.attr,
Michael Marineau86d56132014-04-10 14:09:31 -0700215#endif
Dave Hansen22b8ce92008-10-15 22:01:46 -0700216#ifdef CONFIG_PROFILING
217 &profiling_attr.attr,
218#endif
Dave Young2965faa2015-09-09 15:38:55 -0700219#ifdef CONFIG_KEXEC_CORE
Jeff Moyerc330dda2006-06-23 02:05:07 -0700220 &kexec_loaded_attr.attr,
221 &kexec_crash_loaded_attr.attr,
Amerigo Wang06a7f712009-12-15 16:47:46 -0800222 &kexec_crash_size_attr.attr,
Hari Bathini692f66f2017-05-08 15:56:18 -0700223#endif
224#ifdef CONFIG_CRASH_CORE
Ken'ichi Ohmichifd59d232007-10-16 23:27:27 -0700225 &vmcoreinfo_attr.attr,
Jeff Moyerc330dda2006-06-23 02:05:07 -0700226#endif
Paul E. McKenney79cfea022015-12-07 13:09:52 -0800227#ifndef CONFIG_TINY_RCU
Antti P Miettinen3705b882012-10-05 09:59:15 +0300228 &rcu_expedited_attr.attr,
Paul E. McKenney5a9be7c2015-11-24 15:44:06 -0800229 &rcu_normal_attr.attr,
Paul E. McKenney79cfea022015-12-07 13:09:52 -0800230#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 NULL
232};
233
Arvind Yadav9dcdcea2017-07-10 15:51:14 -0700234static const struct attribute_group kernel_attr_group = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 .attrs = kernel_attrs,
236};
237
238static int __init ksysfs_init(void)
239{
Greg Kroah-Hartmanbd35b932007-10-29 20:13:17 +0100240 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241
Greg Kroah-Hartman0ff21e42007-11-06 10:36:58 -0800242 kernel_kobj = kobject_create_and_add("kernel", NULL);
243 if (!kernel_kobj) {
Greg Kroah-Hartmanbd35b932007-10-29 20:13:17 +0100244 error = -ENOMEM;
245 goto exit;
246 }
Greg Kroah-Hartman0ff21e42007-11-06 10:36:58 -0800247 error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
Greg Kroah-Hartmanbd35b932007-10-29 20:13:17 +0100248 if (error)
249 goto kset_exit;
250
251 if (notes_size > 0) {
Roland McGrathda1a6792007-07-19 01:48:39 -0700252 notes_attr.size = notes_size;
Greg Kroah-Hartman0ff21e42007-11-06 10:36:58 -0800253 error = sysfs_create_bin_file(kernel_kobj, &notes_attr);
Greg Kroah-Hartmanbd35b932007-10-29 20:13:17 +0100254 if (error)
255 goto group_exit;
Roland McGrathda1a6792007-07-19 01:48:39 -0700256 }
257
Greg Kroah-Hartmanbd35b932007-10-29 20:13:17 +0100258 return 0;
259
Greg Kroah-Hartmanbd35b932007-10-29 20:13:17 +0100260group_exit:
Greg Kroah-Hartman0ff21e42007-11-06 10:36:58 -0800261 sysfs_remove_group(kernel_kobj, &kernel_attr_group);
Greg Kroah-Hartmanbd35b932007-10-29 20:13:17 +0100262kset_exit:
Greg Kroah-Hartman78a2d902007-12-20 08:13:05 -0800263 kobject_put(kernel_kobj);
Greg Kroah-Hartmanbd35b932007-10-29 20:13:17 +0100264exit:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265 return error;
266}
267
268core_initcall(ksysfs_init);