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 <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);