/*
 * Procedures for exposing kaslr debugging information.
 *
 * Jia Ma,  Samsung Research America,  Sep 2015
 * Copyright (C) 2015 Jia Ma.
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#include <linux/debugfs.h>
#include <linux/seq_file.h>

#if defined(CONFIG_DEBUG_FS)
static int kaslr_debug_show(struct seq_file *m, void *private)
{
#define TEXT_OFFSET 0x80000
	u64 const kernel_offset = kimage_vaddr - KIMAGE_VADDR;
	u64 kernel_addr = SZ_2G + TEXT_OFFSET + kernel_offset;

	seq_printf(m, "0x%016llx..0x%016llx..\n",
		   kernel_addr, kernel_offset);

	return 0;
}

static int kaslr_debug_open(struct inode *inode, struct file *file)
{
	return single_open(file, kaslr_debug_show, inode->i_private);
}

static const struct file_operations kaslr_debug_fops = {
	.open = kaslr_debug_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
};

static int __init kaslr_init_debugfs(void)
{
	struct dentry *root = debugfs_create_dir("kaslr", NULL);

	if (!root)
		return -ENXIO;
	debugfs_create_file("kaslr", 0400, root, NULL, &kaslr_debug_fops);

	return 0;
}

device_initcall(kaslr_init_debugfs);
#endif /*CONFIG_DEBUG_FS*/