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// 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 sysfs_emit(buf, "%llu\n", (u64)atomic64_read(&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/* address bits */
 55static ssize_t address_bits_show(struct kobject *kobj,
 56				 struct kobj_attribute *attr, char *buf)
 57{
 58	return sysfs_emit(buf, "%zu\n", sizeof(void *) * 8 /* CHAR_BIT */);
 59}
 60KERNEL_ATTR_RO(address_bits);
 61
 62#ifdef CONFIG_UEVENT_HELPER
 63/* uevent helper program, used during early boot */
 64static ssize_t uevent_helper_show(struct kobject *kobj,
 65				  struct kobj_attribute *attr, char *buf)
 66{
 67	return sysfs_emit(buf, "%s\n", uevent_helper);
 68}
 69static ssize_t uevent_helper_store(struct kobject *kobj,
 70				   struct kobj_attribute *attr,
 71				   const char *buf, size_t count)
 72{
 73	if (count+1 > UEVENT_HELPER_PATH_LEN)
 74		return -ENOENT;
 75	memcpy(uevent_helper, buf, count);
 76	uevent_helper[count] = '\0';
 77	if (count && uevent_helper[count-1] == '\n')
 78		uevent_helper[count-1] = '\0';
 79	return count;
 80}
 81KERNEL_ATTR_RW(uevent_helper);
 82#endif
 83
 84#ifdef CONFIG_PROFILING
 85static ssize_t profiling_show(struct kobject *kobj,
 86				  struct kobj_attribute *attr, char *buf)
 87{
 88	return sysfs_emit(buf, "%d\n", prof_on);
 89}
 90static ssize_t profiling_store(struct kobject *kobj,
 91				   struct kobj_attribute *attr,
 92				   const char *buf, size_t count)
 93{
 94	int ret;
 95	static DEFINE_MUTEX(lock);
 96
 97	/*
 98	 * We need serialization, for profile_setup() initializes prof_on
 99	 * value and profile_init() must not reallocate prof_buffer after
100	 * once allocated.
101	 */
102	guard(mutex)(&lock);
103	if (prof_on)
104		return -EEXIST;
105	/*
106	 * This eventually calls into get_option() which
107	 * has a ton of callers and is not const.  It is
108	 * easiest to cast it away here.
109	 */
110	profile_setup((char *)buf);
111	ret = profile_init();
112	if (ret)
113		return ret;
114	ret = create_proc_profile();
115	if (ret)
116		return ret;
117	return count;
118}
119KERNEL_ATTR_RW(profiling);
120#endif
121
122#ifdef CONFIG_KEXEC_CORE
123static ssize_t kexec_loaded_show(struct kobject *kobj,
124				 struct kobj_attribute *attr, char *buf)
125{
126	return sysfs_emit(buf, "%d\n", !!kexec_image);
127}
128KERNEL_ATTR_RO(kexec_loaded);
129
130#ifdef CONFIG_CRASH_DUMP
131static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
132				       struct kobj_attribute *attr, char *buf)
133{
134	return sysfs_emit(buf, "%d\n", kexec_crash_loaded());
135}
136KERNEL_ATTR_RO(kexec_crash_loaded);
137
138static ssize_t kexec_crash_size_show(struct kobject *kobj,
139				       struct kobj_attribute *attr, char *buf)
140{
141	ssize_t size = crash_get_memory_size();
142
143	if (size < 0)
144		return size;
145
146	return sysfs_emit(buf, "%zd\n", size);
147}
148static ssize_t kexec_crash_size_store(struct kobject *kobj,
149				   struct kobj_attribute *attr,
150				   const char *buf, size_t count)
151{
152	unsigned long cnt;
153	int ret;
154
155	if (kstrtoul(buf, 0, &cnt))
156		return -EINVAL;
157
158	ret = crash_shrink_memory(cnt);
159	return ret < 0 ? ret : count;
160}
161KERNEL_ATTR_RW(kexec_crash_size);
162
163#endif /* CONFIG_CRASH_DUMP*/
164#endif /* CONFIG_KEXEC_CORE */
165
166#ifdef CONFIG_VMCORE_INFO
167
168static ssize_t vmcoreinfo_show(struct kobject *kobj,
169			       struct kobj_attribute *attr, char *buf)
170{
171	phys_addr_t vmcore_base = paddr_vmcoreinfo_note();
172	return sysfs_emit(buf, "%pa %x\n", &vmcore_base,
173			  (unsigned int)VMCOREINFO_NOTE_SIZE);
174}
175KERNEL_ATTR_RO(vmcoreinfo);
176
177#ifdef CONFIG_CRASH_HOTPLUG
178static ssize_t crash_elfcorehdr_size_show(struct kobject *kobj,
179			       struct kobj_attribute *attr, char *buf)
180{
181	unsigned int sz = crash_get_elfcorehdr_size();
182
183	return sysfs_emit(buf, "%u\n", sz);
184}
185KERNEL_ATTR_RO(crash_elfcorehdr_size);
186
187#endif
188
189#endif /* CONFIG_VMCORE_INFO */
190
191/* whether file capabilities are enabled */
192static ssize_t fscaps_show(struct kobject *kobj,
193				  struct kobj_attribute *attr, char *buf)
194{
195	return sysfs_emit(buf, "%d\n", file_caps_enabled);
196}
197KERNEL_ATTR_RO(fscaps);
198
199#ifndef CONFIG_TINY_RCU
200int rcu_expedited;
201static ssize_t rcu_expedited_show(struct kobject *kobj,
202				  struct kobj_attribute *attr, char *buf)
203{
204	return sysfs_emit(buf, "%d\n", READ_ONCE(rcu_expedited));
205}
206static ssize_t rcu_expedited_store(struct kobject *kobj,
207				   struct kobj_attribute *attr,
208				   const char *buf, size_t count)
209{
210	if (kstrtoint(buf, 0, &rcu_expedited))
211		return -EINVAL;
212
213	return count;
214}
215KERNEL_ATTR_RW(rcu_expedited);
216
217int rcu_normal;
218static ssize_t rcu_normal_show(struct kobject *kobj,
219			       struct kobj_attribute *attr, char *buf)
220{
221	return sysfs_emit(buf, "%d\n", READ_ONCE(rcu_normal));
222}
223static ssize_t rcu_normal_store(struct kobject *kobj,
224				struct kobj_attribute *attr,
225				const char *buf, size_t count)
226{
227	if (kstrtoint(buf, 0, &rcu_normal))
228		return -EINVAL;
229
230	return count;
231}
232KERNEL_ATTR_RW(rcu_normal);
233#endif /* #ifndef CONFIG_TINY_RCU */
234
235/*
236 * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
237 */
238extern const void __start_notes;
239extern const void __stop_notes;
240#define	notes_size (&__stop_notes - &__start_notes)
241
242static ssize_t notes_read(struct file *filp, struct kobject *kobj,
243			  struct bin_attribute *bin_attr,
244			  char *buf, loff_t off, size_t count)
245{
246	memcpy(buf, &__start_notes + off, count);
247	return count;
248}
249
250static struct bin_attribute notes_attr __ro_after_init  = {
251	.attr = {
252		.name = "notes",
253		.mode = S_IRUGO,
254	},
255	.read = &notes_read,
256};
257
258struct kobject *kernel_kobj;
259EXPORT_SYMBOL_GPL(kernel_kobj);
260
261static struct attribute * kernel_attrs[] = {
262	&fscaps_attr.attr,
263	&uevent_seqnum_attr.attr,
264	&cpu_byteorder_attr.attr,
265	&address_bits_attr.attr,
266#ifdef CONFIG_UEVENT_HELPER
267	&uevent_helper_attr.attr,
268#endif
269#ifdef CONFIG_PROFILING
270	&profiling_attr.attr,
271#endif
272#ifdef CONFIG_KEXEC_CORE
273	&kexec_loaded_attr.attr,
274#ifdef CONFIG_CRASH_DUMP
275	&kexec_crash_loaded_attr.attr,
276	&kexec_crash_size_attr.attr,
277#endif
278#endif
279#ifdef CONFIG_VMCORE_INFO
280	&vmcoreinfo_attr.attr,
281#ifdef CONFIG_CRASH_HOTPLUG
282	&crash_elfcorehdr_size_attr.attr,
283#endif
284#endif
285#ifndef CONFIG_TINY_RCU
286	&rcu_expedited_attr.attr,
287	&rcu_normal_attr.attr,
288#endif
289	NULL
290};
291
292static const struct attribute_group kernel_attr_group = {
293	.attrs = kernel_attrs,
294};
295
296static int __init ksysfs_init(void)
297{
298	int error;
299
300	kernel_kobj = kobject_create_and_add("kernel", NULL);
301	if (!kernel_kobj) {
302		error = -ENOMEM;
303		goto exit;
304	}
305	error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
306	if (error)
307		goto kset_exit;
308
309	if (notes_size > 0) {
310		notes_attr.size = notes_size;
311		error = sysfs_create_bin_file(kernel_kobj, &notes_attr);
312		if (error)
313			goto group_exit;
314	}
315
316	return 0;
317
318group_exit:
319	sysfs_remove_group(kernel_kobj, &kernel_attr_group);
320kset_exit:
321	kobject_put(kernel_kobj);
322exit:
323	return error;
324}
325
326core_initcall(ksysfs_init);