text: // SPDX-License-Identifier: GPL-2.0-only
  /*
   * memconsole.c
   *
   * Architecture-independent parts of the memory based BIOS console.
   *
   * Copyright 2017 Google Inc.
   */
  
  #include <linux/sysfs.h>
  #include <linux/kobject.h>
  #include <linux/module.h>
  
  #include "memconsole.h"
  
  static ssize_t memconsole_read(struct file *filp, struct kobject *kobp,
  			       struct bin_attribute *bin_attr, char *buf,
  			       loff_t pos, size_t count)
  {
  	ssize_t (*memconsole_read_func)(char *, loff_t, size_t);
  
  	memconsole_read_func = bin_attr->private;
  	if (WARN_ON_ONCE(!memconsole_read_func))
  		return -EIO;
  
  	return memconsole_read_func(buf, pos, count);
  }
  
  static struct bin_attribute memconsole_bin_attr = {
  	.attr = {.name = "log", .mode = 0444},
  	.read = memconsole_read,
  };
  
  void memconsole_setup(ssize_t (*read_func)(char *, loff_t, size_t))
  {
  	memconsole_bin_attr.private = read_func;
  }
  EXPORT_SYMBOL(memconsole_setup);
  
  int memconsole_sysfs_init(void)
  {
  	return sysfs_create_bin_file(firmware_kobj, &memconsole_bin_attr);
  }
  EXPORT_SYMBOL(memconsole_sysfs_init);
  
  void memconsole_exit(void)
  {
  	sysfs_remove_bin_file(firmware_kobj, &memconsole_bin_attr);
  }
  EXPORT_SYMBOL(memconsole_exit);
  
  MODULE_AUTHOR("Google, Inc.");
  MODULE_LICENSE("GPL");
  