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
 22#define KERNEL_ATTR_RO(_name) \
 23static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
 24
 25#define KERNEL_ATTR_RW(_name) \
 26static struct kobj_attribute _name##_attr = \
 27	__ATTR(_name, 0644, _name##_show, _name##_store)
 28
 29#if defined(CONFIG_HOTPLUG)
 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/* uevent helper program, used during early boot */
 39static ssize_t uevent_helper_show(struct kobject *kobj,
 40				  struct kobj_attribute *attr, char *buf)
 41{
 42	return sprintf(buf, "%s\n", uevent_helper);
 43}
 44static ssize_t uevent_helper_store(struct kobject *kobj,
 45				   struct kobj_attribute *attr,
 46				   const char *buf, size_t count)
 47{
 48	if (count+1 > UEVENT_HELPER_PATH_LEN)
 49		return -ENOENT;
 50	memcpy(uevent_helper, buf, count);
 51	uevent_helper[count] = '\0';
 52	if (count && uevent_helper[count-1] == '\n')
 53		uevent_helper[count-1] = '\0';
 54	return count;
 55}
 56KERNEL_ATTR_RW(uevent_helper);
 57#endif
 58
 59#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
 90#ifdef CONFIG_KEXEC
 91static ssize_t kexec_loaded_show(struct kobject *kobj,
 92				 struct kobj_attribute *attr, char *buf)
 93{
 94	return sprintf(buf, "%d\n", !!kexec_image);
 95}
 96KERNEL_ATTR_RO(kexec_loaded);
 97
 98static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
 99				       struct kobj_attribute *attr, char *buf)
100{
101	return sprintf(buf, "%d\n", !!kexec_crash_image);
102}
103KERNEL_ATTR_RO(kexec_crash_loaded);
104
105static 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
117	if (strict_strtoul(buf, 0, &cnt))
118		return -EINVAL;
119
120	ret = crash_shrink_memory(cnt);
121	return ret < 0 ? ret : count;
122}
123KERNEL_ATTR_RW(kexec_crash_size);
124
 
 
 
 
125static ssize_t vmcoreinfo_show(struct kobject *kobj,
126			       struct kobj_attribute *attr, char *buf)
127{
128	return sprintf(buf, "%lx %x\n",
129		       paddr_vmcoreinfo_note(),
130		       (unsigned int)vmcoreinfo_max_size);
131}
132KERNEL_ATTR_RO(vmcoreinfo);
133
134#endif /* CONFIG_KEXEC */
135
136/* whether file capabilities are enabled */
137static ssize_t fscaps_show(struct kobject *kobj,
138				  struct kobj_attribute *attr, char *buf)
139{
140	return sprintf(buf, "%d\n", file_caps_enabled);
141}
142KERNEL_ATTR_RO(fscaps);
143
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
144/*
145 * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
146 */
147extern const void __start_notes __attribute__((weak));
148extern const void __stop_notes __attribute__((weak));
149#define	notes_size (&__stop_notes - &__start_notes)
150
151static ssize_t notes_read(struct file *filp, struct kobject *kobj,
152			  struct bin_attribute *bin_attr,
153			  char *buf, loff_t off, size_t count)
154{
155	memcpy(buf, &__start_notes + off, count);
156	return count;
157}
158
159static struct bin_attribute notes_attr = {
160	.attr = {
161		.name = "notes",
162		.mode = S_IRUGO,
163	},
164	.read = &notes_read,
165};
166
167struct kobject *kernel_kobj;
168EXPORT_SYMBOL_GPL(kernel_kobj);
169
170static struct attribute * kernel_attrs[] = {
171	&fscaps_attr.attr,
172#if defined(CONFIG_HOTPLUG)
173	&uevent_seqnum_attr.attr,
 
 
174	&uevent_helper_attr.attr,
175#endif
176#ifdef CONFIG_PROFILING
177	&profiling_attr.attr,
178#endif
179#ifdef CONFIG_KEXEC
180	&kexec_loaded_attr.attr,
181	&kexec_crash_loaded_attr.attr,
182	&kexec_crash_size_attr.attr,
 
 
183	&vmcoreinfo_attr.attr,
184#endif
 
 
 
 
185	NULL
186};
187
188static struct attribute_group kernel_attr_group = {
189	.attrs = kernel_attrs,
190};
191
192static int __init ksysfs_init(void)
193{
194	int error;
195
196	kernel_kobj = kobject_create_and_add("kernel", NULL);
197	if (!kernel_kobj) {
198		error = -ENOMEM;
199		goto exit;
200	}
201	error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
202	if (error)
203		goto kset_exit;
204
205	if (notes_size > 0) {
206		notes_attr.size = notes_size;
207		error = sysfs_create_bin_file(kernel_kobj, &notes_attr);
208		if (error)
209			goto group_exit;
210	}
211
212	return 0;
213
214group_exit:
215	sysfs_remove_group(kernel_kobj, &kernel_attr_group);
216kset_exit:
217	kobject_put(kernel_kobj);
218exit:
219	return error;
220}
221
222core_initcall(ksysfs_init);