Merge tag 'nfs-for-6.12-1' of git://git.linux-nfs.org/projects/anna/linux-nfs
[linux-2.6-block.git] / kernel / ksysfs.c
CommitLineData
468e15fd 1// SPDX-License-Identifier: GPL-2.0-only
1da177e4
LT
2/*
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>
1da177e4
LT
7 */
8
d3d76fbd 9#include <asm/byteorder.h>
1da177e4
LT
10#include <linux/kobject.h>
11#include <linux/string.h>
12#include <linux/sysfs.h>
9984de1a 13#include <linux/export.h>
1da177e4 14#include <linux/init.h>
c330dda9 15#include <linux/kexec.h>
22b8ce94 16#include <linux/profile.h>
1596425f 17#include <linux/stat.h>
5cb350ba 18#include <linux/sched.h>
088ab0b4 19#include <linux/capability.h>
52f5684c 20#include <linux/compiler.h>
1da177e4 21
5a9be7c6 22#include <linux/rcupdate.h> /* rcu_expedited and rcu_normal */
7a754743 23
d3d76fbd
TW
24#if defined(__LITTLE_ENDIAN)
25#define CPU_BYTEORDER_STRING "little"
26#elif defined(__BIG_ENDIAN)
27#define CPU_BYTEORDER_STRING "big"
28#else
29#error Unknown byteorder
30#endif
31
1da177e4 32#define KERNEL_ATTR_RO(_name) \
386f275f 33static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1da177e4
LT
34
35#define KERNEL_ATTR_RW(_name) \
a7cd9a53 36static struct kobj_attribute _name##_attr = __ATTR_RW(_name)
1da177e4 37
0f76e5ac 38/* current uevent sequence number */
386f275f
KS
39static ssize_t uevent_seqnum_show(struct kobject *kobj,
40 struct kobj_attribute *attr, char *buf)
1da177e4 41{
2444a80c 42 return sysfs_emit(buf, "%llu\n", (u64)atomic64_read(&uevent_seqnum));
1da177e4 43}
0f76e5ac
KS
44KERNEL_ATTR_RO(uevent_seqnum);
45
d3d76fbd
TW
46/* cpu byteorder */
47static ssize_t cpu_byteorder_show(struct kobject *kobj,
48 struct kobj_attribute *attr, char *buf)
49{
50 return sysfs_emit(buf, "%s\n", CPU_BYTEORDER_STRING);
51}
52KERNEL_ATTR_RO(cpu_byteorder);
53
00142bfd
TW
54/* address bits */
55static ssize_t address_bits_show(struct kobject *kobj,
56 struct kobj_attribute *attr, char *buf)
57{
58 return sysfs_emit(buf, "%zu\n", sizeof(void *) * 8 /* CHAR_BIT */);
59}
60KERNEL_ATTR_RO(address_bits);
61
86d56134 62#ifdef CONFIG_UEVENT_HELPER
af665852 63/* uevent helper program, used during early boot */
386f275f
KS
64static ssize_t uevent_helper_show(struct kobject *kobj,
65 struct kobj_attribute *attr, char *buf)
0f76e5ac 66{
9f33a88c 67 return sysfs_emit(buf, "%s\n", uevent_helper);
0f76e5ac 68}
386f275f
KS
69static ssize_t uevent_helper_store(struct kobject *kobj,
70 struct kobj_attribute *attr,
71 const char *buf, size_t count)
0f76e5ac 72{
312c004d 73 if (count+1 > UEVENT_HELPER_PATH_LEN)
0f76e5ac 74 return -ENOENT;
386f275f 75 memcpy(uevent_helper, buf, count);
312c004d
KS
76 uevent_helper[count] = '\0';
77 if (count && uevent_helper[count-1] == '\n')
78 uevent_helper[count-1] = '\0';
0f76e5ac
KS
79 return count;
80}
81KERNEL_ATTR_RW(uevent_helper);
86d56134 82#endif
1da177e4 83
22b8ce94
DH
84#ifdef CONFIG_PROFILING
85static ssize_t profiling_show(struct kobject *kobj,
86 struct kobj_attribute *attr, char *buf)
87{
9f33a88c 88 return sysfs_emit(buf, "%d\n", prof_on);
22b8ce94
DH
89}
90static ssize_t profiling_store(struct kobject *kobj,
91 struct kobj_attribute *attr,
92 const char *buf, size_t count)
93{
94 int ret;
7c51f7bb 95 static DEFINE_MUTEX(lock);
22b8ce94 96
7c51f7bb
TH
97 /*
98 * We need serialization, for profile_setup() initializes prof_on
99 * value and profile_init() must not reallocate prof_buffer after
100 * once allocated.
101 */
102 guard(mutex)(&lock);
22b8ce94
DH
103 if (prof_on)
104 return -EEXIST;
105 /*
106 * This eventually calls into get_option() which
107 * has a ton of callers and is not const. It is
108 * easiest to cast it away here.
109 */
110 profile_setup((char *)buf);
111 ret = profile_init();
112 if (ret)
113 return ret;
114 ret = create_proc_profile();
115 if (ret)
116 return ret;
117 return count;
118}
119KERNEL_ATTR_RW(profiling);
120#endif
121
2965faa5 122#ifdef CONFIG_KEXEC_CORE
386f275f
KS
123static ssize_t kexec_loaded_show(struct kobject *kobj,
124 struct kobj_attribute *attr, char *buf)
c330dda9 125{
9f33a88c 126 return sysfs_emit(buf, "%d\n", !!kexec_image);
c330dda9
JM
127}
128KERNEL_ATTR_RO(kexec_loaded);
129
02aff848 130#ifdef CONFIG_CRASH_DUMP
386f275f
KS
131static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
132 struct kobj_attribute *attr, char *buf)
c330dda9 133{
9f33a88c 134 return sysfs_emit(buf, "%d\n", kexec_crash_loaded());
c330dda9
JM
135}
136KERNEL_ATTR_RO(kexec_crash_loaded);
fd59d231 137
06a7f711
AW
138static ssize_t kexec_crash_size_show(struct kobject *kobj,
139 struct kobj_attribute *attr, char *buf)
140{
7bb5da0d
VS
141 ssize_t size = crash_get_memory_size();
142
143 if (size < 0)
144 return size;
145
9f33a88c 146 return sysfs_emit(buf, "%zd\n", size);
06a7f711
AW
147}
148static ssize_t kexec_crash_size_store(struct kobject *kobj,
149 struct kobj_attribute *attr,
150 const char *buf, size_t count)
151{
152 unsigned long cnt;
153 int ret;
154
6072ddc8 155 if (kstrtoul(buf, 0, &cnt))
06a7f711
AW
156 return -EINVAL;
157
158 ret = crash_shrink_memory(cnt);
159 return ret < 0 ? ret : count;
160}
161KERNEL_ATTR_RW(kexec_crash_size);
162
02aff848 163#endif /* CONFIG_CRASH_DUMP*/
692f66f2
HB
164#endif /* CONFIG_KEXEC_CORE */
165
443cbaf9 166#ifdef CONFIG_VMCORE_INFO
692f66f2 167
386f275f
KS
168static ssize_t vmcoreinfo_show(struct kobject *kobj,
169 struct kobj_attribute *attr, char *buf)
fd59d231 170{
dae28018 171 phys_addr_t vmcore_base = paddr_vmcoreinfo_note();
9f33a88c
TW
172 return sysfs_emit(buf, "%pa %x\n", &vmcore_base,
173 (unsigned int)VMCOREINFO_NOTE_SIZE);
fd59d231
KO
174}
175KERNEL_ATTR_RO(vmcoreinfo);
176
a72bbec7
ED
177#ifdef CONFIG_CRASH_HOTPLUG
178static ssize_t crash_elfcorehdr_size_show(struct kobject *kobj,
179 struct kobj_attribute *attr, char *buf)
180{
181 unsigned int sz = crash_get_elfcorehdr_size();
182
183 return sysfs_emit(buf, "%u\n", sz);
184}
185KERNEL_ATTR_RO(crash_elfcorehdr_size);
186
187#endif
188
443cbaf9 189#endif /* CONFIG_VMCORE_INFO */
c330dda9 190
088ab0b4
LN
191/* whether file capabilities are enabled */
192static ssize_t fscaps_show(struct kobject *kobj,
193 struct kobj_attribute *attr, char *buf)
194{
9f33a88c 195 return sysfs_emit(buf, "%d\n", file_caps_enabled);
088ab0b4
LN
196}
197KERNEL_ATTR_RO(fscaps);
198
79cfea02 199#ifndef CONFIG_TINY_RCU
3705b88d
AM
200int rcu_expedited;
201static ssize_t rcu_expedited_show(struct kobject *kobj,
202 struct kobj_attribute *attr, char *buf)
203{
9f33a88c 204 return sysfs_emit(buf, "%d\n", READ_ONCE(rcu_expedited));
3705b88d
AM
205}
206static ssize_t rcu_expedited_store(struct kobject *kobj,
207 struct kobj_attribute *attr,
208 const char *buf, size_t count)
209{
210 if (kstrtoint(buf, 0, &rcu_expedited))
211 return -EINVAL;
212
213 return count;
214}
215KERNEL_ATTR_RW(rcu_expedited);
216
5a9be7c6
PM
217int rcu_normal;
218static ssize_t rcu_normal_show(struct kobject *kobj,
219 struct kobj_attribute *attr, char *buf)
220{
9f33a88c 221 return sysfs_emit(buf, "%d\n", READ_ONCE(rcu_normal));
5a9be7c6
PM
222}
223static ssize_t rcu_normal_store(struct kobject *kobj,
224 struct kobj_attribute *attr,
225 const char *buf, size_t count)
226{
227 if (kstrtoint(buf, 0, &rcu_normal))
228 return -EINVAL;
229
230 return count;
231}
232KERNEL_ATTR_RW(rcu_normal);
79cfea02 233#endif /* #ifndef CONFIG_TINY_RCU */
5a9be7c6 234
da1a679c
RM
235/*
236 * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
237 */
377d9095
AB
238extern const void __start_notes;
239extern const void __stop_notes;
da1a679c
RM
240#define notes_size (&__stop_notes - &__start_notes)
241
2c3c8bea
CW
242static ssize_t notes_read(struct file *filp, struct kobject *kobj,
243 struct bin_attribute *bin_attr,
da1a679c
RM
244 char *buf, loff_t off, size_t count)
245{
246 memcpy(buf, &__start_notes + off, count);
247 return count;
248}
249
738bc38d 250static struct bin_attribute notes_attr __ro_after_init = {
da1a679c
RM
251 .attr = {
252 .name = "notes",
253 .mode = S_IRUGO,
254 },
255 .read = &notes_read,
256};
257
0ff21e46
GKH
258struct kobject *kernel_kobj;
259EXPORT_SYMBOL_GPL(kernel_kobj);
1da177e4
LT
260
261static struct attribute * kernel_attrs[] = {
088ab0b4 262 &fscaps_attr.attr,
0f76e5ac 263 &uevent_seqnum_attr.attr,
d3d76fbd 264 &cpu_byteorder_attr.attr,
00142bfd 265 &address_bits_attr.attr,
86d56134 266#ifdef CONFIG_UEVENT_HELPER
0f76e5ac 267 &uevent_helper_attr.attr,
86d56134 268#endif
22b8ce94
DH
269#ifdef CONFIG_PROFILING
270 &profiling_attr.attr,
271#endif
2965faa5 272#ifdef CONFIG_KEXEC_CORE
c330dda9 273 &kexec_loaded_attr.attr,
02aff848 274#ifdef CONFIG_CRASH_DUMP
c330dda9 275 &kexec_crash_loaded_attr.attr,
06a7f711 276 &kexec_crash_size_attr.attr,
692f66f2 277#endif
02aff848 278#endif
443cbaf9 279#ifdef CONFIG_VMCORE_INFO
fd59d231 280 &vmcoreinfo_attr.attr,
a72bbec7
ED
281#ifdef CONFIG_CRASH_HOTPLUG
282 &crash_elfcorehdr_size_attr.attr,
283#endif
1da177e4 284#endif
79cfea02 285#ifndef CONFIG_TINY_RCU
3705b88d 286 &rcu_expedited_attr.attr,
5a9be7c6 287 &rcu_normal_attr.attr,
79cfea02 288#endif
1da177e4
LT
289 NULL
290};
291
9dcdcea1 292static const struct attribute_group kernel_attr_group = {
1da177e4
LT
293 .attrs = kernel_attrs,
294};
295
296static int __init ksysfs_init(void)
297{
bd35b93d 298 int error;
1da177e4 299
0ff21e46
GKH
300 kernel_kobj = kobject_create_and_add("kernel", NULL);
301 if (!kernel_kobj) {
bd35b93d
GKH
302 error = -ENOMEM;
303 goto exit;
304 }
0ff21e46 305 error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
bd35b93d
GKH
306 if (error)
307 goto kset_exit;
308
309 if (notes_size > 0) {
da1a679c 310 notes_attr.size = notes_size;
0ff21e46 311 error = sysfs_create_bin_file(kernel_kobj, &notes_attr);
bd35b93d
GKH
312 if (error)
313 goto group_exit;
da1a679c
RM
314 }
315
bd35b93d
GKH
316 return 0;
317
bd35b93d 318group_exit:
0ff21e46 319 sysfs_remove_group(kernel_kobj, &kernel_attr_group);
bd35b93d 320kset_exit:
78a2d906 321 kobject_put(kernel_kobj);
bd35b93d 322exit:
1da177e4
LT
323 return error;
324}
325
326core_initcall(ksysfs_init);