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 */
 
 
 
 
 
 
 
 
 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/* uevent helper program, used during early boot */
 41static ssize_t uevent_helper_show(struct kobject *kobj,
 42				  struct kobj_attribute *attr, char *buf)
 43{
 44	return sprintf(buf, "%s\n", uevent_helper);
 45}
 46static ssize_t uevent_helper_store(struct kobject *kobj,
 47				   struct kobj_attribute *attr,
 48				   const char *buf, size_t count)
 49{
 50	if (count+1 > UEVENT_HELPER_PATH_LEN)
 51		return -ENOENT;
 52	memcpy(uevent_helper, buf, count);
 53	uevent_helper[count] = '\0';
 54	if (count && uevent_helper[count-1] == '\n')
 55		uevent_helper[count-1] = '\0';
 56	return count;
 57}
 58KERNEL_ATTR_RW(uevent_helper);
 59
 60
 61#ifdef CONFIG_PROFILING
 62static ssize_t profiling_show(struct kobject *kobj,
 63				  struct kobj_attribute *attr, char *buf)
 64{
 65	return sprintf(buf, "%d\n", prof_on);
 66}
 67static ssize_t profiling_store(struct kobject *kobj,
 68				   struct kobj_attribute *attr,
 69				   const char *buf, size_t count)
 70{
 71	int ret;
 72
 73	if (prof_on)
 74		return -EEXIST;
 75	/*
 76	 * This eventually calls into get_option() which
 77	 * has a ton of callers and is not const.  It is
 78	 * easiest to cast it away here.
 79	 */
 80	profile_setup((char *)buf);
 81	ret = profile_init();
 82	if (ret)
 83		return ret;
 84	ret = create_proc_profile();
 85	if (ret)
 86		return ret;
 87	return count;
 88}
 89KERNEL_ATTR_RW(profiling);
 90#endif
 91
 92#ifdef CONFIG_KEXEC
 93static ssize_t kexec_loaded_show(struct kobject *kobj,
 94				 struct kobj_attribute *attr, char *buf)
 95{
 96	return sprintf(buf, "%d\n", !!kexec_image);
 97}
 98KERNEL_ATTR_RO(kexec_loaded);
 99
100static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
101				       struct kobj_attribute *attr, char *buf)
102{
103	return sprintf(buf, "%d\n", !!kexec_crash_image);
104}
105KERNEL_ATTR_RO(kexec_crash_loaded);
106
107static ssize_t kexec_crash_size_show(struct kobject *kobj,
108				       struct kobj_attribute *attr, char *buf)
109{
110	return sprintf(buf, "%zu\n", crash_get_memory_size());
 
 
 
 
 
111}
112static ssize_t kexec_crash_size_store(struct kobject *kobj,
113				   struct kobj_attribute *attr,
114				   const char *buf, size_t count)
115{
116	unsigned long cnt;
117	int ret;
118
119	if (kstrtoul(buf, 0, &cnt))
120		return -EINVAL;
121
122	ret = crash_shrink_memory(cnt);
123	return ret < 0 ? ret : count;
124}
125KERNEL_ATTR_RW(kexec_crash_size);
126
 
 
 
 
127static ssize_t vmcoreinfo_show(struct kobject *kobj,
128			       struct kobj_attribute *attr, char *buf)
129{
130	return sprintf(buf, "%lx %x\n",
131		       paddr_vmcoreinfo_note(),
132		       (unsigned int)sizeof(vmcoreinfo_note));
133}
134KERNEL_ATTR_RO(vmcoreinfo);
135
136#endif /* CONFIG_KEXEC */
 
 
 
 
 
 
 
 
 
 
 
 
137
138/* whether file capabilities are enabled */
139static ssize_t fscaps_show(struct kobject *kobj,
140				  struct kobj_attribute *attr, char *buf)
141{
142	return sprintf(buf, "%d\n", file_caps_enabled);
143}
144KERNEL_ATTR_RO(fscaps);
145
 
146int rcu_expedited;
147static ssize_t rcu_expedited_show(struct kobject *kobj,
148				  struct kobj_attribute *attr, char *buf)
149{
150	return sprintf(buf, "%d\n", rcu_expedited);
151}
152static ssize_t rcu_expedited_store(struct kobject *kobj,
153				   struct kobj_attribute *attr,
154				   const char *buf, size_t count)
155{
156	if (kstrtoint(buf, 0, &rcu_expedited))
157		return -EINVAL;
158
159	return count;
160}
161KERNEL_ATTR_RW(rcu_expedited);
162
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
163/*
164 * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
165 */
166extern const void __start_notes __weak;
167extern const void __stop_notes __weak;
168#define	notes_size (&__stop_notes - &__start_notes)
169
170static ssize_t notes_read(struct file *filp, struct kobject *kobj,
171			  struct bin_attribute *bin_attr,
172			  char *buf, loff_t off, size_t count)
173{
174	memcpy(buf, &__start_notes + off, count);
175	return count;
176}
177
178static struct bin_attribute notes_attr = {
179	.attr = {
180		.name = "notes",
181		.mode = S_IRUGO,
182	},
183	.read = &notes_read,
184};
185
186struct kobject *kernel_kobj;
187EXPORT_SYMBOL_GPL(kernel_kobj);
188
189static struct attribute * kernel_attrs[] = {
190	&fscaps_attr.attr,
191	&uevent_seqnum_attr.attr,
 
 
 
192	&uevent_helper_attr.attr,
 
193#ifdef CONFIG_PROFILING
194	&profiling_attr.attr,
195#endif
196#ifdef CONFIG_KEXEC
197	&kexec_loaded_attr.attr,
198	&kexec_crash_loaded_attr.attr,
199	&kexec_crash_size_attr.attr,
 
 
200	&vmcoreinfo_attr.attr,
 
 
201#endif
 
 
202	&rcu_expedited_attr.attr,
 
 
203	NULL
204};
205
206static struct attribute_group kernel_attr_group = {
207	.attrs = kernel_attrs,
208};
209
210static int __init ksysfs_init(void)
211{
212	int error;
213
214	kernel_kobj = kobject_create_and_add("kernel", NULL);
215	if (!kernel_kobj) {
216		error = -ENOMEM;
217		goto exit;
218	}
219	error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
220	if (error)
221		goto kset_exit;
222
223	if (notes_size > 0) {
224		notes_attr.size = notes_size;
225		error = sysfs_create_bin_file(kernel_kobj, &notes_attr);
226		if (error)
227			goto group_exit;
228	}
229
230	return 0;
231
232group_exit:
233	sysfs_remove_group(kernel_kobj, &kernel_attr_group);
234kset_exit:
235	kobject_put(kernel_kobj);
236exit:
237	return error;
238}
239
240core_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", (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);