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// 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);