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