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", (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);