1 files changed, 315 insertions, 0 deletions
diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c
new file mode 100644
index 0000000000..1d4bc493b2
--- /dev/null
+++ b/kernel/ksysfs.c
@@ -0,0 +1,315 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kernel/ksysfs.c - sysfs attributes in /sys/kernel, which
+ * 		     are not related to any other subsystem
+ *
+ * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
+ */
+
+#include <asm/byteorder.h>
+#include <linux/kobject.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/kexec.h>
+#include <linux/profile.h>
+#include <linux/stat.h>
+#include <linux/sched.h>
+#include <linux/capability.h>
+#include <linux/compiler.h>
+
+#include <linux/rcupdate.h>	/* rcu_expedited and rcu_normal */
+
+#if defined(__LITTLE_ENDIAN)
+#define CPU_BYTEORDER_STRING	"little"
+#elif defined(__BIG_ENDIAN)
+#define CPU_BYTEORDER_STRING	"big"
+#else
+#error Unknown byteorder
+#endif
+
+#define KERNEL_ATTR_RO(_name) \
+static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
+
+#define KERNEL_ATTR_RW(_name) \
+static struct kobj_attribute _name##_attr = __ATTR_RW(_name)
+
+/* current uevent sequence number */
+static ssize_t uevent_seqnum_show(struct kobject *kobj,
+				  struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%llu\n", (unsigned long long)uevent_seqnum);
+}
+KERNEL_ATTR_RO(uevent_seqnum);
+
+/* cpu byteorder */
+static ssize_t cpu_byteorder_show(struct kobject *kobj,
+				  struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%s\n", CPU_BYTEORDER_STRING);
+}
+KERNEL_ATTR_RO(cpu_byteorder);
+
+/* address bits */
+static ssize_t address_bits_show(struct kobject *kobj,
+				 struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%zu\n", sizeof(void *) * 8 /* CHAR_BIT */);
+}
+KERNEL_ATTR_RO(address_bits);
+
+#ifdef CONFIG_UEVENT_HELPER
+/* uevent helper program, used during early boot */
+static ssize_t uevent_helper_show(struct kobject *kobj,
+				  struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%s\n", uevent_helper);
+}
+static ssize_t uevent_helper_store(struct kobject *kobj,
+				   struct kobj_attribute *attr,
+				   const char *buf, size_t count)
+{
+	if (count+1 > UEVENT_HELPER_PATH_LEN)
+		return -ENOENT;
+	memcpy(uevent_helper, buf, count);
+	uevent_helper[count] = '\0';
+	if (count && uevent_helper[count-1] == '\n')
+		uevent_helper[count-1] = '\0';
+	return count;
+}
+KERNEL_ATTR_RW(uevent_helper);
+#endif
+
+#ifdef CONFIG_PROFILING
+static ssize_t profiling_show(struct kobject *kobj,
+				  struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%d\n", prof_on);
+}
+static ssize_t profiling_store(struct kobject *kobj,
+				   struct kobj_attribute *attr,
+				   const char *buf, size_t count)
+{
+	int ret;
+
+	if (prof_on)
+		return -EEXIST;
+	/*
+	 * This eventually calls into get_option() which
+	 * has a ton of callers and is not const.  It is
+	 * easiest to cast it away here.
+	 */
+	profile_setup((char *)buf);
+	ret = profile_init();
+	if (ret)
+		return ret;
+	ret = create_proc_profile();
+	if (ret)
+		return ret;
+	return count;
+}
+KERNEL_ATTR_RW(profiling);
+#endif
+
+#ifdef CONFIG_KEXEC_CORE
+static ssize_t kexec_loaded_show(struct kobject *kobj,
+				 struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%d\n", !!kexec_image);
+}
+KERNEL_ATTR_RO(kexec_loaded);
+
+static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
+				       struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%d\n", kexec_crash_loaded());
+}
+KERNEL_ATTR_RO(kexec_crash_loaded);
+
+static ssize_t kexec_crash_size_show(struct kobject *kobj,
+				       struct kobj_attribute *attr, char *buf)
+{
+	ssize_t size = crash_get_memory_size();
+
+	if (size < 0)
+		return size;
+
+	return sysfs_emit(buf, "%zd\n", size);
+}
+static ssize_t kexec_crash_size_store(struct kobject *kobj,
+				   struct kobj_attribute *attr,
+				   const char *buf, size_t count)
+{
+	unsigned long cnt;
+	int ret;
+
+	if (kstrtoul(buf, 0, &cnt))
+		return -EINVAL;
+
+	ret = crash_shrink_memory(cnt);
+	return ret < 0 ? ret : count;
+}
+KERNEL_ATTR_RW(kexec_crash_size);
+
+#endif /* CONFIG_KEXEC_CORE */
+
+#ifdef CONFIG_CRASH_CORE
+
+static ssize_t vmcoreinfo_show(struct kobject *kobj,
+			       struct kobj_attribute *attr, char *buf)
+{
+	phys_addr_t vmcore_base = paddr_vmcoreinfo_note();
+	return sysfs_emit(buf, "%pa %x\n", &vmcore_base,
+			  (unsigned int)VMCOREINFO_NOTE_SIZE);
+}
+KERNEL_ATTR_RO(vmcoreinfo);
+
+#ifdef CONFIG_CRASH_HOTPLUG
+static ssize_t crash_elfcorehdr_size_show(struct kobject *kobj,
+			       struct kobj_attribute *attr, char *buf)
+{
+	unsigned int sz = crash_get_elfcorehdr_size();
+
+	return sysfs_emit(buf, "%u\n", sz);
+}
+KERNEL_ATTR_RO(crash_elfcorehdr_size);
+
+#endif
+
+#endif /* CONFIG_CRASH_CORE */
+
+/* whether file capabilities are enabled */
+static ssize_t fscaps_show(struct kobject *kobj,
+				  struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%d\n", file_caps_enabled);
+}
+KERNEL_ATTR_RO(fscaps);
+
+#ifndef CONFIG_TINY_RCU
+int rcu_expedited;
+static ssize_t rcu_expedited_show(struct kobject *kobj,
+				  struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%d\n", READ_ONCE(rcu_expedited));
+}
+static ssize_t rcu_expedited_store(struct kobject *kobj,
+				   struct kobj_attribute *attr,
+				   const char *buf, size_t count)
+{
+	if (kstrtoint(buf, 0, &rcu_expedited))
+		return -EINVAL;
+
+	return count;
+}
+KERNEL_ATTR_RW(rcu_expedited);
+
+int rcu_normal;
+static ssize_t rcu_normal_show(struct kobject *kobj,
+			       struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%d\n", READ_ONCE(rcu_normal));
+}
+static ssize_t rcu_normal_store(struct kobject *kobj,
+				struct kobj_attribute *attr,
+				const char *buf, size_t count)
+{
+	if (kstrtoint(buf, 0, &rcu_normal))
+		return -EINVAL;
+
+	return count;
+}
+KERNEL_ATTR_RW(rcu_normal);
+#endif /* #ifndef CONFIG_TINY_RCU */
+
+/*
+ * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
+ */
+extern const void __start_notes __weak;
+extern const void __stop_notes __weak;
+#define	notes_size (&__stop_notes - &__start_notes)
+
+static ssize_t notes_read(struct file *filp, struct kobject *kobj,
+			  struct bin_attribute *bin_attr,
+			  char *buf, loff_t off, size_t count)
+{
+	memcpy(buf, &__start_notes + off, count);
+	return count;
+}
+
+static struct bin_attribute notes_attr __ro_after_init  = {
+	.attr = {
+		.name = "notes",
+		.mode = S_IRUGO,
+	},
+	.read = &notes_read,
+};
+
+struct kobject *kernel_kobj;
+EXPORT_SYMBOL_GPL(kernel_kobj);
+
+static struct attribute * kernel_attrs[] = {
+	&fscaps_attr.attr,
+	&uevent_seqnum_attr.attr,
+	&cpu_byteorder_attr.attr,
+	&address_bits_attr.attr,
+#ifdef CONFIG_UEVENT_HELPER
+	&uevent_helper_attr.attr,
+#endif
+#ifdef CONFIG_PROFILING
+	&profiling_attr.attr,
+#endif
+#ifdef CONFIG_KEXEC_CORE
+	&kexec_loaded_attr.attr,
+	&kexec_crash_loaded_attr.attr,
+	&kexec_crash_size_attr.attr,
+#endif
+#ifdef CONFIG_CRASH_CORE
+	&vmcoreinfo_attr.attr,
+#ifdef CONFIG_CRASH_HOTPLUG
+	&crash_elfcorehdr_size_attr.attr,
+#endif
+#endif
+#ifndef CONFIG_TINY_RCU
+	&rcu_expedited_attr.attr,
+	&rcu_normal_attr.attr,
+#endif
+	NULL
+};
+
+static const struct attribute_group kernel_attr_group = {
+	.attrs = kernel_attrs,
+};
+
+static int __init ksysfs_init(void)
+{
+	int error;
+
+	kernel_kobj = kobject_create_and_add("kernel", NULL);
+	if (!kernel_kobj) {
+		error = -ENOMEM;
+		goto exit;
+	}
+	error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
+	if (error)
+		goto kset_exit;
+
+	if (notes_size > 0) {
+		notes_attr.size = notes_size;
+		error = sysfs_create_bin_file(kernel_kobj, &notes_attr);
+		if (error)
+			goto group_exit;
+	}
+
+	return 0;
+
+group_exit:
+	sysfs_remove_group(kernel_kobj, &kernel_attr_group);
+kset_exit:
+	kobject_put(kernel_kobj);
+exit:
+	return error;
+}
+
+core_initcall(ksysfs_init);