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 <asm/byteorder.h>
 10#include <linux/kobject.h>
 11#include <linux/string.h>
 12#include <linux/sysfs.h>
 13#include <linux/export.h>
 14#include <linux/init.h>
 15#include <linux/kexec.h>
 16#include <linux/profile.h>
 17#include <linux/stat.h>
 18#include <linux/sched.h>
 19#include <linux/capability.h>
 20#include <linux/compiler.h>
 21
 22#include <linux/rcupdate.h>	/* rcu_expedited and rcu_normal */
 23
 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
 32#define KERNEL_ATTR_RO(_name) \
 33static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
 34
 35#define KERNEL_ATTR_RW(_name) \
 36static struct kobj_attribute _name##_attr = __ATTR_RW(_name)
 
 37
 38/* current uevent sequence number */
 39static ssize_t uevent_seqnum_show(struct kobject *kobj,
 40				  struct kobj_attribute *attr, char *buf)
 41{
 42	return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum);
 43}
 44KERNEL_ATTR_RO(uevent_seqnum);
 45
 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
 54#ifdef CONFIG_UEVENT_HELPER
 55/* uevent helper program, used during early boot */
 56static ssize_t uevent_helper_show(struct kobject *kobj,
 57				  struct kobj_attribute *attr, char *buf)
 58{
 59	return sprintf(buf, "%s\n", uevent_helper);
 60}
 61static ssize_t uevent_helper_store(struct kobject *kobj,
 62				   struct kobj_attribute *attr,
 63				   const char *buf, size_t count)
 64{
 65	if (count+1 > UEVENT_HELPER_PATH_LEN)
 66		return -ENOENT;
 67	memcpy(uevent_helper, buf, count);
 68	uevent_helper[count] = '\0';
 69	if (count && uevent_helper[count-1] == '\n')
 70		uevent_helper[count-1] = '\0';
 71	return count;
 72}
 73KERNEL_ATTR_RW(uevent_helper);
 74#endif
 75
 76#ifdef CONFIG_PROFILING
 77static ssize_t profiling_show(struct kobject *kobj,
 78				  struct kobj_attribute *attr, char *buf)
 79{
 80	return sprintf(buf, "%d\n", prof_on);
 81}
 82static ssize_t profiling_store(struct kobject *kobj,
 83				   struct kobj_attribute *attr,
 84				   const char *buf, size_t count)
 85{
 86	int ret;
 87
 88	if (prof_on)
 89		return -EEXIST;
 90	/*
 91	 * This eventually calls into get_option() which
 92	 * has a ton of callers and is not const.  It is
 93	 * easiest to cast it away here.
 94	 */
 95	profile_setup((char *)buf);
 96	ret = profile_init();
 97	if (ret)
 98		return ret;
 99	ret = create_proc_profile();
100	if (ret)
101		return ret;
102	return count;
103}
104KERNEL_ATTR_RW(profiling);
105#endif
106
107#ifdef CONFIG_KEXEC_CORE
108static ssize_t kexec_loaded_show(struct kobject *kobj,
109				 struct kobj_attribute *attr, char *buf)
110{
111	return sprintf(buf, "%d\n", !!kexec_image);
112}
113KERNEL_ATTR_RO(kexec_loaded);
114
115static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
116				       struct kobj_attribute *attr, char *buf)
117{
118	return sprintf(buf, "%d\n", kexec_crash_loaded());
119}
120KERNEL_ATTR_RO(kexec_crash_loaded);
121
122static ssize_t kexec_crash_size_show(struct kobject *kobj,
123				       struct kobj_attribute *attr, char *buf)
124{
125	ssize_t size = crash_get_memory_size();
126
127	if (size < 0)
128		return size;
129
130	return sprintf(buf, "%zd\n", size);
131}
132static ssize_t kexec_crash_size_store(struct kobject *kobj,
133				   struct kobj_attribute *attr,
134				   const char *buf, size_t count)
135{
136	unsigned long cnt;
137	int ret;
138
139	if (kstrtoul(buf, 0, &cnt))
140		return -EINVAL;
141
142	ret = crash_shrink_memory(cnt);
143	return ret < 0 ? ret : count;
144}
145KERNEL_ATTR_RW(kexec_crash_size);
146
147#endif /* CONFIG_KEXEC_CORE */
148
149#ifdef CONFIG_CRASH_CORE
150
151static ssize_t vmcoreinfo_show(struct kobject *kobj,
152			       struct kobj_attribute *attr, char *buf)
153{
154	phys_addr_t vmcore_base = paddr_vmcoreinfo_note();
155	return sprintf(buf, "%pa %x\n", &vmcore_base,
156			(unsigned int)VMCOREINFO_NOTE_SIZE);
157}
158KERNEL_ATTR_RO(vmcoreinfo);
159
160#endif /* CONFIG_CRASH_CORE */
161
162/* whether file capabilities are enabled */
163static ssize_t fscaps_show(struct kobject *kobj,
164				  struct kobj_attribute *attr, char *buf)
165{
166	return sprintf(buf, "%d\n", file_caps_enabled);
167}
168KERNEL_ATTR_RO(fscaps);
169
170#ifndef CONFIG_TINY_RCU
171int rcu_expedited;
172static ssize_t rcu_expedited_show(struct kobject *kobj,
173				  struct kobj_attribute *attr, char *buf)
174{
175	return sprintf(buf, "%d\n", READ_ONCE(rcu_expedited));
176}
177static ssize_t rcu_expedited_store(struct kobject *kobj,
178				   struct kobj_attribute *attr,
179				   const char *buf, size_t count)
180{
181	if (kstrtoint(buf, 0, &rcu_expedited))
182		return -EINVAL;
183
184	return count;
185}
186KERNEL_ATTR_RW(rcu_expedited);
187
188int rcu_normal;
189static ssize_t rcu_normal_show(struct kobject *kobj,
190			       struct kobj_attribute *attr, char *buf)
191{
192	return sprintf(buf, "%d\n", READ_ONCE(rcu_normal));
193}
194static ssize_t rcu_normal_store(struct kobject *kobj,
195				struct kobj_attribute *attr,
196				const char *buf, size_t count)
197{
198	if (kstrtoint(buf, 0, &rcu_normal))
199		return -EINVAL;
200
201	return count;
202}
203KERNEL_ATTR_RW(rcu_normal);
204#endif /* #ifndef CONFIG_TINY_RCU */
205
206/*
207 * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
208 */
209extern const void __start_notes __weak;
210extern const void __stop_notes __weak;
211#define	notes_size (&__stop_notes - &__start_notes)
212
213static ssize_t notes_read(struct file *filp, struct kobject *kobj,
214			  struct bin_attribute *bin_attr,
215			  char *buf, loff_t off, size_t count)
216{
217	memcpy(buf, &__start_notes + off, count);
218	return count;
219}
220
221static struct bin_attribute notes_attr __ro_after_init  = {
222	.attr = {
223		.name = "notes",
224		.mode = S_IRUGO,
225	},
226	.read = &notes_read,
227};
228
229struct kobject *kernel_kobj;
230EXPORT_SYMBOL_GPL(kernel_kobj);
231
232static struct attribute * kernel_attrs[] = {
233	&fscaps_attr.attr,
234	&uevent_seqnum_attr.attr,
235	&cpu_byteorder_attr.attr,
236#ifdef CONFIG_UEVENT_HELPER
237	&uevent_helper_attr.attr,
238#endif
239#ifdef CONFIG_PROFILING
240	&profiling_attr.attr,
241#endif
242#ifdef CONFIG_KEXEC_CORE
243	&kexec_loaded_attr.attr,
244	&kexec_crash_loaded_attr.attr,
245	&kexec_crash_size_attr.attr,
246#endif
247#ifdef CONFIG_CRASH_CORE
248	&vmcoreinfo_attr.attr,
249#endif
250#ifndef CONFIG_TINY_RCU
251	&rcu_expedited_attr.attr,
252	&rcu_normal_attr.attr,
253#endif
254	NULL
255};
256
257static const struct attribute_group kernel_attr_group = {
258	.attrs = kernel_attrs,
259};
260
261static int __init ksysfs_init(void)
262{
263	int error;
264
265	kernel_kobj = kobject_create_and_add("kernel", NULL);
266	if (!kernel_kobj) {
267		error = -ENOMEM;
268		goto exit;
269	}
270	error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
271	if (error)
272		goto kset_exit;
273
274	if (notes_size > 0) {
275		notes_attr.size = notes_size;
276		error = sysfs_create_bin_file(kernel_kobj, &notes_attr);
277		if (error)
278			goto group_exit;
279	}
280
281	return 0;
282
283group_exit:
284	sysfs_remove_group(kernel_kobj, &kernel_attr_group);
285kset_exit:
286	kobject_put(kernel_kobj);
287exit:
288	return error;
289}
290
291core_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/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_loaded());
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
128#endif /* CONFIG_KEXEC_CORE */
129
130#ifdef CONFIG_CRASH_CORE
131
132static ssize_t vmcoreinfo_show(struct kobject *kobj,
133			       struct kobj_attribute *attr, char *buf)
134{
135	phys_addr_t vmcore_base = paddr_vmcoreinfo_note();
136	return sprintf(buf, "%pa %x\n", &vmcore_base,
137			(unsigned int)VMCOREINFO_NOTE_SIZE);
138}
139KERNEL_ATTR_RO(vmcoreinfo);
140
141#endif /* CONFIG_CRASH_CORE */
142
143/* whether file capabilities are enabled */
144static ssize_t fscaps_show(struct kobject *kobj,
145				  struct kobj_attribute *attr, char *buf)
146{
147	return sprintf(buf, "%d\n", file_caps_enabled);
148}
149KERNEL_ATTR_RO(fscaps);
150
151#ifndef CONFIG_TINY_RCU
152int rcu_expedited;
153static ssize_t rcu_expedited_show(struct kobject *kobj,
154				  struct kobj_attribute *attr, char *buf)
155{
156	return sprintf(buf, "%d\n", READ_ONCE(rcu_expedited));
157}
158static ssize_t rcu_expedited_store(struct kobject *kobj,
159				   struct kobj_attribute *attr,
160				   const char *buf, size_t count)
161{
162	if (kstrtoint(buf, 0, &rcu_expedited))
163		return -EINVAL;
164
165	return count;
166}
167KERNEL_ATTR_RW(rcu_expedited);
168
169int rcu_normal;
170static ssize_t rcu_normal_show(struct kobject *kobj,
171			       struct kobj_attribute *attr, char *buf)
172{
173	return sprintf(buf, "%d\n", READ_ONCE(rcu_normal));
174}
175static ssize_t rcu_normal_store(struct kobject *kobj,
176				struct kobj_attribute *attr,
177				const char *buf, size_t count)
178{
179	if (kstrtoint(buf, 0, &rcu_normal))
180		return -EINVAL;
181
182	return count;
183}
184KERNEL_ATTR_RW(rcu_normal);
185#endif /* #ifndef CONFIG_TINY_RCU */
186
187/*
188 * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
189 */
190extern const void __start_notes __weak;
191extern const void __stop_notes __weak;
192#define	notes_size (&__stop_notes - &__start_notes)
193
194static ssize_t notes_read(struct file *filp, struct kobject *kobj,
195			  struct bin_attribute *bin_attr,
196			  char *buf, loff_t off, size_t count)
197{
198	memcpy(buf, &__start_notes + off, count);
199	return count;
200}
201
202static struct bin_attribute notes_attr __ro_after_init  = {
203	.attr = {
204		.name = "notes",
205		.mode = S_IRUGO,
206	},
207	.read = &notes_read,
208};
209
210struct kobject *kernel_kobj;
211EXPORT_SYMBOL_GPL(kernel_kobj);
212
213static struct attribute * kernel_attrs[] = {
214	&fscaps_attr.attr,
215	&uevent_seqnum_attr.attr,
 
216#ifdef CONFIG_UEVENT_HELPER
217	&uevent_helper_attr.attr,
218#endif
219#ifdef CONFIG_PROFILING
220	&profiling_attr.attr,
221#endif
222#ifdef CONFIG_KEXEC_CORE
223	&kexec_loaded_attr.attr,
224	&kexec_crash_loaded_attr.attr,
225	&kexec_crash_size_attr.attr,
226#endif
227#ifdef CONFIG_CRASH_CORE
228	&vmcoreinfo_attr.attr,
229#endif
230#ifndef CONFIG_TINY_RCU
231	&rcu_expedited_attr.attr,
232	&rcu_normal_attr.attr,
233#endif
234	NULL
235};
236
237static const struct attribute_group kernel_attr_group = {
238	.attrs = kernel_attrs,
239};
240
241static int __init ksysfs_init(void)
242{
243	int error;
244
245	kernel_kobj = kobject_create_and_add("kernel", NULL);
246	if (!kernel_kobj) {
247		error = -ENOMEM;
248		goto exit;
249	}
250	error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
251	if (error)
252		goto kset_exit;
253
254	if (notes_size > 0) {
255		notes_attr.size = notes_size;
256		error = sysfs_create_bin_file(kernel_kobj, &notes_attr);
257		if (error)
258			goto group_exit;
259	}
260
261	return 0;
262
263group_exit:
264	sysfs_remove_group(kernel_kobj, &kernel_attr_group);
265kset_exit:
266	kobject_put(kernel_kobj);
267exit:
268	return error;
269}
270
271core_initcall(ksysfs_init);