1/*
  2 * kernel/ksysfs.c - sysfs attributes in /sys/kernel, which
  3 * 		     are not related to any other subsystem
  4 *
  5 * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
  6 * 
  7 * This file is release under the GPLv2
  8 *
  9 */
 10
 11#include <linux/kobject.h>
 12#include <linux/string.h>
 13#include <linux/sysfs.h>
 14#include <linux/export.h>
 15#include <linux/init.h>
 16#include <linux/kexec.h>
 17#include <linux/profile.h>
 18#include <linux/stat.h>
 19#include <linux/sched.h>
 20#include <linux/capability.h>
 21#include <linux/compiler.h>
 22
 23#include <linux/rcupdate.h>	/* rcu_expedited and rcu_normal */
 24
 25#define KERNEL_ATTR_RO(_name) \
 26static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
 27
 28#define KERNEL_ATTR_RW(_name) \
 29static struct kobj_attribute _name##_attr = \
 30	__ATTR(_name, 0644, _name##_show, _name##_store)
 31
 32/* current uevent sequence number */
 33static ssize_t uevent_seqnum_show(struct kobject *kobj,
 34				  struct kobj_attribute *attr, char *buf)
 35{
 36	return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum);
 37}
 38KERNEL_ATTR_RO(uevent_seqnum);
 39
 40#ifdef CONFIG_UEVENT_HELPER
 41/* uevent helper program, used during early boot */
 42static ssize_t uevent_helper_show(struct kobject *kobj,
 43				  struct kobj_attribute *attr, char *buf)
 44{
 45	return sprintf(buf, "%s\n", uevent_helper);
 46}
 47static ssize_t uevent_helper_store(struct kobject *kobj,
 48				   struct kobj_attribute *attr,
 49				   const char *buf, size_t count)
 50{
 51	if (count+1 > UEVENT_HELPER_PATH_LEN)
 52		return -ENOENT;
 53	memcpy(uevent_helper, buf, count);
 54	uevent_helper[count] = '\0';
 55	if (count && uevent_helper[count-1] == '\n')
 56		uevent_helper[count-1] = '\0';
 57	return count;
 58}
 59KERNEL_ATTR_RW(uevent_helper);
 60#endif
 61
 62#ifdef CONFIG_PROFILING
 63static ssize_t profiling_show(struct kobject *kobj,
 64				  struct kobj_attribute *attr, char *buf)
 65{
 66	return sprintf(buf, "%d\n", prof_on);
 67}
 68static ssize_t profiling_store(struct kobject *kobj,
 69				   struct kobj_attribute *attr,
 70				   const char *buf, size_t count)
 71{
 72	int ret;
 73
 74	if (prof_on)
 75		return -EEXIST;
 76	/*
 77	 * This eventually calls into get_option() which
 78	 * has a ton of callers and is not const.  It is
 79	 * easiest to cast it away here.
 80	 */
 81	profile_setup((char *)buf);
 82	ret = profile_init();
 83	if (ret)
 84		return ret;
 85	ret = create_proc_profile();
 86	if (ret)
 87		return ret;
 88	return count;
 89}
 90KERNEL_ATTR_RW(profiling);
 91#endif
 92
 93#ifdef CONFIG_KEXEC_CORE
 94static ssize_t kexec_loaded_show(struct kobject *kobj,
 95				 struct kobj_attribute *attr, char *buf)
 96{
 97	return sprintf(buf, "%d\n", !!kexec_image);
 98}
 99KERNEL_ATTR_RO(kexec_loaded);
100
101static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
102				       struct kobj_attribute *attr, char *buf)
103{
104	return sprintf(buf, "%d\n", !!kexec_crash_image);
105}
106KERNEL_ATTR_RO(kexec_crash_loaded);
107
108static ssize_t kexec_crash_size_show(struct kobject *kobj,
109				       struct kobj_attribute *attr, char *buf)
110{
111	return sprintf(buf, "%zu\n", crash_get_memory_size());
112}
113static ssize_t kexec_crash_size_store(struct kobject *kobj,
114				   struct kobj_attribute *attr,
115				   const char *buf, size_t count)
116{
117	unsigned long cnt;
118	int ret;
119
120	if (kstrtoul(buf, 0, &cnt))
121		return -EINVAL;
122
123	ret = crash_shrink_memory(cnt);
124	return ret < 0 ? ret : count;
125}
126KERNEL_ATTR_RW(kexec_crash_size);
127
128static ssize_t vmcoreinfo_show(struct kobject *kobj,
129			       struct kobj_attribute *attr, char *buf)
130{
131	return sprintf(buf, "%lx %x\n",
132		       paddr_vmcoreinfo_note(),
133		       (unsigned int)sizeof(vmcoreinfo_note));
134}
135KERNEL_ATTR_RO(vmcoreinfo);
136
137#endif /* CONFIG_KEXEC_CORE */
138
139/* whether file capabilities are enabled */
140static ssize_t fscaps_show(struct kobject *kobj,
141				  struct kobj_attribute *attr, char *buf)
142{
143	return sprintf(buf, "%d\n", file_caps_enabled);
144}
145KERNEL_ATTR_RO(fscaps);
146
147#ifndef CONFIG_TINY_RCU
148int rcu_expedited;
149static ssize_t rcu_expedited_show(struct kobject *kobj,
150				  struct kobj_attribute *attr, char *buf)
151{
152	return sprintf(buf, "%d\n", READ_ONCE(rcu_expedited));
153}
154static ssize_t rcu_expedited_store(struct kobject *kobj,
155				   struct kobj_attribute *attr,
156				   const char *buf, size_t count)
157{
158	if (kstrtoint(buf, 0, &rcu_expedited))
159		return -EINVAL;
160
161	return count;
162}
163KERNEL_ATTR_RW(rcu_expedited);
164
165int rcu_normal;
166static ssize_t rcu_normal_show(struct kobject *kobj,
167			       struct kobj_attribute *attr, char *buf)
168{
169	return sprintf(buf, "%d\n", READ_ONCE(rcu_normal));
170}
171static ssize_t rcu_normal_store(struct kobject *kobj,
172				struct kobj_attribute *attr,
173				const char *buf, size_t count)
174{
175	if (kstrtoint(buf, 0, &rcu_normal))
176		return -EINVAL;
177
178	return count;
179}
180KERNEL_ATTR_RW(rcu_normal);
181#endif /* #ifndef CONFIG_TINY_RCU */
182
183/*
184 * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
185 */
186extern const void __start_notes __weak;
187extern const void __stop_notes __weak;
188#define	notes_size (&__stop_notes - &__start_notes)
189
190static ssize_t notes_read(struct file *filp, struct kobject *kobj,
191			  struct bin_attribute *bin_attr,
192			  char *buf, loff_t off, size_t count)
193{
194	memcpy(buf, &__start_notes + off, count);
195	return count;
196}
197
198static struct bin_attribute notes_attr = {
199	.attr = {
200		.name = "notes",
201		.mode = S_IRUGO,
202	},
203	.read = &notes_read,
204};
205
206struct kobject *kernel_kobj;
207EXPORT_SYMBOL_GPL(kernel_kobj);
208
209static struct attribute * kernel_attrs[] = {
210	&fscaps_attr.attr,
211	&uevent_seqnum_attr.attr,
212#ifdef CONFIG_UEVENT_HELPER
213	&uevent_helper_attr.attr,
214#endif
215#ifdef CONFIG_PROFILING
216	&profiling_attr.attr,
217#endif
218#ifdef CONFIG_KEXEC_CORE
219	&kexec_loaded_attr.attr,
220	&kexec_crash_loaded_attr.attr,
221	&kexec_crash_size_attr.attr,
222	&vmcoreinfo_attr.attr,
223#endif
224#ifndef CONFIG_TINY_RCU
225	&rcu_expedited_attr.attr,
226	&rcu_normal_attr.attr,
227#endif
228	NULL
229};
230
231static struct attribute_group kernel_attr_group = {
232	.attrs = kernel_attrs,
233};
234
235static int __init ksysfs_init(void)
236{
237	int error;
238
239	kernel_kobj = kobject_create_and_add("kernel", NULL);
240	if (!kernel_kobj) {
241		error = -ENOMEM;
242		goto exit;
243	}
244	error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
245	if (error)
246		goto kset_exit;
247
248	if (notes_size > 0) {
249		notes_attr.size = notes_size;
250		error = sysfs_create_bin_file(kernel_kobj, &notes_attr);
251		if (error)
252			goto group_exit;
253	}
254
255	return 0;
256
257group_exit:
258	sysfs_remove_group(kernel_kobj, &kernel_attr_group);
259kset_exit:
260	kobject_put(kernel_kobj);
261exit:
262	return error;
263}
264
265core_initcall(ksysfs_init);

  1// SPDX-License-Identifier: GPL-2.0-only
  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>
  7 */
  8
  9#include <linux/kobject.h>
 10#include <linux/string.h>
 11#include <linux/sysfs.h>
 12#include <linux/export.h>
 13#include <linux/init.h>
 14#include <linux/kexec.h>
 15#include <linux/profile.h>
 16#include <linux/stat.h>
 17#include <linux/sched.h>
 18#include <linux/capability.h>
 19#include <linux/compiler.h>
 20
 21#include <linux/rcupdate.h>	/* rcu_expedited and rcu_normal */
 22
 23#define KERNEL_ATTR_RO(_name) \
 24static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
 25
 26#define KERNEL_ATTR_RW(_name) \
 27static struct kobj_attribute _name##_attr = \
 28	__ATTR(_name, 0644, _name##_show, _name##_store)
 29
 30/* current uevent sequence number */
 31static ssize_t uevent_seqnum_show(struct kobject *kobj,
 32				  struct kobj_attribute *attr, char *buf)
 33{
 34	return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum);
 35}
 36KERNEL_ATTR_RO(uevent_seqnum);
 37
 38#ifdef CONFIG_UEVENT_HELPER
 39/* uevent helper program, used during early boot */
 40static ssize_t uevent_helper_show(struct kobject *kobj,
 41				  struct kobj_attribute *attr, char *buf)
 42{
 43	return sprintf(buf, "%s\n", uevent_helper);
 44}
 45static ssize_t uevent_helper_store(struct kobject *kobj,
 46				   struct kobj_attribute *attr,
 47				   const char *buf, size_t count)
 48{
 49	if (count+1 > UEVENT_HELPER_PATH_LEN)
 50		return -ENOENT;
 51	memcpy(uevent_helper, buf, count);
 52	uevent_helper[count] = '\0';
 53	if (count && uevent_helper[count-1] == '\n')
 54		uevent_helper[count-1] = '\0';
 55	return count;
 56}
 57KERNEL_ATTR_RW(uevent_helper);
 58#endif
 59
 60#ifdef CONFIG_PROFILING
 61static ssize_t profiling_show(struct kobject *kobj,
 62				  struct kobj_attribute *attr, char *buf)
 63{
 64	return sprintf(buf, "%d\n", prof_on);
 65}
 66static ssize_t profiling_store(struct kobject *kobj,
 67				   struct kobj_attribute *attr,
 68				   const char *buf, size_t count)
 69{
 70	int ret;
 71
 72	if (prof_on)
 73		return -EEXIST;
 74	/*
 75	 * This eventually calls into get_option() which
 76	 * has a ton of callers and is not const.  It is
 77	 * easiest to cast it away here.
 78	 */
 79	profile_setup((char *)buf);
 80	ret = profile_init();
 81	if (ret)
 82		return ret;
 83	ret = create_proc_profile();
 84	if (ret)
 85		return ret;
 86	return count;
 87}
 88KERNEL_ATTR_RW(profiling);
 89#endif
 90
 91#ifdef CONFIG_KEXEC_CORE
 92static ssize_t kexec_loaded_show(struct kobject *kobj,
 93				 struct kobj_attribute *attr, char *buf)
 94{
 95	return sprintf(buf, "%d\n", !!kexec_image);
 96}
 97KERNEL_ATTR_RO(kexec_loaded);
 98
 99static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
100				       struct kobj_attribute *attr, char *buf)
101{
102	return sprintf(buf, "%d\n", kexec_crash_loaded());
103}
104KERNEL_ATTR_RO(kexec_crash_loaded);
105
106static ssize_t kexec_crash_size_show(struct kobject *kobj,
107				       struct kobj_attribute *attr, char *buf)
108{
109	return sprintf(buf, "%zu\n", crash_get_memory_size());
110}
111static ssize_t kexec_crash_size_store(struct kobject *kobj,
112				   struct kobj_attribute *attr,
113				   const char *buf, size_t count)
114{
115	unsigned long cnt;
116	int ret;
117
118	if (kstrtoul(buf, 0, &cnt))
119		return -EINVAL;
120
121	ret = crash_shrink_memory(cnt);
122	return ret < 0 ? ret : count;
123}
124KERNEL_ATTR_RW(kexec_crash_size);
125
126#endif /* CONFIG_KEXEC_CORE */
127
128#ifdef CONFIG_CRASH_CORE
129
130static ssize_t vmcoreinfo_show(struct kobject *kobj,
131			       struct kobj_attribute *attr, char *buf)
132{
133	phys_addr_t vmcore_base = paddr_vmcoreinfo_note();
134	return sprintf(buf, "%pa %x\n", &vmcore_base,
135			(unsigned int)VMCOREINFO_NOTE_SIZE);
136}
137KERNEL_ATTR_RO(vmcoreinfo);
138
139#endif /* CONFIG_CRASH_CORE */
140
141/* whether file capabilities are enabled */
142static ssize_t fscaps_show(struct kobject *kobj,
143				  struct kobj_attribute *attr, char *buf)
144{
145	return sprintf(buf, "%d\n", file_caps_enabled);
146}
147KERNEL_ATTR_RO(fscaps);
148
149#ifndef CONFIG_TINY_RCU
150int rcu_expedited;
151static ssize_t rcu_expedited_show(struct kobject *kobj,
152				  struct kobj_attribute *attr, char *buf)
153{
154	return sprintf(buf, "%d\n", READ_ONCE(rcu_expedited));
155}
156static ssize_t rcu_expedited_store(struct kobject *kobj,
157				   struct kobj_attribute *attr,
158				   const char *buf, size_t count)
159{
160	if (kstrtoint(buf, 0, &rcu_expedited))
161		return -EINVAL;
162
163	return count;
164}
165KERNEL_ATTR_RW(rcu_expedited);
166
167int rcu_normal;
168static ssize_t rcu_normal_show(struct kobject *kobj,
169			       struct kobj_attribute *attr, char *buf)
170{
171	return sprintf(buf, "%d\n", READ_ONCE(rcu_normal));
172}
173static ssize_t rcu_normal_store(struct kobject *kobj,
174				struct kobj_attribute *attr,
175				const char *buf, size_t count)
176{
177	if (kstrtoint(buf, 0, &rcu_normal))
178		return -EINVAL;
179
180	return count;
181}
182KERNEL_ATTR_RW(rcu_normal);
183#endif /* #ifndef CONFIG_TINY_RCU */
184
185/*
186 * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
187 */
188extern const void __start_notes __weak;
189extern const void __stop_notes __weak;
190#define	notes_size (&__stop_notes - &__start_notes)
191
192static ssize_t notes_read(struct file *filp, struct kobject *kobj,
193			  struct bin_attribute *bin_attr,
194			  char *buf, loff_t off, size_t count)
195{
196	memcpy(buf, &__start_notes + off, count);
197	return count;
198}
199
200static struct bin_attribute notes_attr __ro_after_init  = {
201	.attr = {
202		.name = "notes",
203		.mode = S_IRUGO,
204	},
205	.read = &notes_read,
206};
207
208struct kobject *kernel_kobj;
209EXPORT_SYMBOL_GPL(kernel_kobj);
210
211static struct attribute * kernel_attrs[] = {
212	&fscaps_attr.attr,
213	&uevent_seqnum_attr.attr,
214#ifdef CONFIG_UEVENT_HELPER
215	&uevent_helper_attr.attr,
216#endif
217#ifdef CONFIG_PROFILING
218	&profiling_attr.attr,
219#endif
220#ifdef CONFIG_KEXEC_CORE
221	&kexec_loaded_attr.attr,
222	&kexec_crash_loaded_attr.attr,
223	&kexec_crash_size_attr.attr,
224#endif
225#ifdef CONFIG_CRASH_CORE
226	&vmcoreinfo_attr.attr,
227#endif
228#ifndef CONFIG_TINY_RCU
229	&rcu_expedited_attr.attr,
230	&rcu_normal_attr.attr,
231#endif
232	NULL
233};
234
235static const struct attribute_group kernel_attr_group = {
236	.attrs = kernel_attrs,
237};
238
239static int __init ksysfs_init(void)
240{
241	int error;
242
243	kernel_kobj = kobject_create_and_add("kernel", NULL);
244	if (!kernel_kobj) {
245		error = -ENOMEM;
246		goto exit;
247	}
248	error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
249	if (error)
250		goto kset_exit;
251
252	if (notes_size > 0) {
253		notes_attr.size = notes_size;
254		error = sysfs_create_bin_file(kernel_kobj, &notes_attr);
255		if (error)
256			goto group_exit;
257	}
258
259	return 0;
260
261group_exit:
262	sysfs_remove_group(kernel_kobj, &kernel_attr_group);
263kset_exit:
264	kobject_put(kernel_kobj);
265exit:
266	return error;
267}
268
269core_initcall(ksysfs_init);