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);

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