/*
   * 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>
   * 
   * This file is release under the GPLv2
   *
   */

  #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 */

  #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(_name, 0644, _name##_show, _name##_store)

  /* current uevent sequence number */

  static ssize_t uevent_seqnum_show(struct kobject *kobj,
  				  struct kobj_attribute *attr, char *buf)

  {

  	return sprintf(buf, "%llu
  ", (unsigned long long)uevent_seqnum);

  }

  KERNEL_ATTR_RO(uevent_seqnum);

  #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 sprintf(buf, "%s
  ", 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] == '
  ')
  		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 sprintf(buf, "%d
  ", 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 sprintf(buf, "%d
  ", !!kexec_image);

  }
  KERNEL_ATTR_RO(kexec_loaded);

  static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
  				       struct kobj_attribute *attr, char *buf)

  {

  	return sprintf(buf, "%d
  ", 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)
  {
  	return sprintf(buf, "%zu
  ", crash_get_memory_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);

  static ssize_t vmcoreinfo_show(struct kobject *kobj,
  			       struct kobj_attribute *attr, char *buf)

  {

  	phys_addr_t vmcore_base = paddr_vmcoreinfo_note();
  	return sprintf(buf, "%pa %x
  ", &vmcore_base,

  		       (unsigned int)sizeof(vmcoreinfo_note));

  }
  KERNEL_ATTR_RO(vmcoreinfo);

  #endif /* CONFIG_KEXEC_CORE */

  /* whether file capabilities are enabled */
  static ssize_t fscaps_show(struct kobject *kobj,
  				  struct kobj_attribute *attr, char *buf)
  {
  	return sprintf(buf, "%d
  ", 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 sprintf(buf, "%d
  ", 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 sprintf(buf, "%d
  ", 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 = {
  	.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,

  #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,

  	&vmcoreinfo_attr.attr,

  #endif

  #ifndef CONFIG_TINY_RCU

  	&rcu_expedited_attr.attr,

  	&rcu_normal_attr.attr,

  #endif

  	NULL
  };
  
  static 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);