cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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mmapper_kern.c (2941B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * arch/um/drivers/mmapper_kern.c
      4 *
      5 * BRIEF MODULE DESCRIPTION
      6 *
      7 * Copyright (C) 2000 RidgeRun, Inc.
      8 * Author: RidgeRun, Inc.
      9 *         Greg Lonnon glonnon@ridgerun.com or info@ridgerun.com
     10 *
     11 */
     12
     13#include <linux/stddef.h>
     14#include <linux/types.h>
     15#include <linux/fs.h>
     16#include <linux/init.h>
     17#include <linux/miscdevice.h>
     18#include <linux/module.h>
     19#include <linux/mm.h>
     20
     21#include <linux/uaccess.h>
     22#include <mem_user.h>
     23
     24/* These are set in mmapper_init, which is called at boot time */
     25static unsigned long mmapper_size;
     26static unsigned long p_buf;
     27static char *v_buf;
     28
     29static ssize_t mmapper_read(struct file *file, char __user *buf, size_t count,
     30			    loff_t *ppos)
     31{
     32	return simple_read_from_buffer(buf, count, ppos, v_buf, mmapper_size);
     33}
     34
     35static ssize_t mmapper_write(struct file *file, const char __user *buf,
     36			     size_t count, loff_t *ppos)
     37{
     38	if (*ppos > mmapper_size)
     39		return -EINVAL;
     40
     41	return simple_write_to_buffer(v_buf, mmapper_size, ppos, buf, count);
     42}
     43
     44static long mmapper_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
     45{
     46	return -ENOIOCTLCMD;
     47}
     48
     49static int mmapper_mmap(struct file *file, struct vm_area_struct *vma)
     50{
     51	int ret = -EINVAL;
     52	int size;
     53
     54	if (vma->vm_pgoff != 0)
     55		goto out;
     56
     57	size = vma->vm_end - vma->vm_start;
     58	if (size > mmapper_size)
     59		return -EFAULT;
     60
     61	/*
     62	 * XXX A comment above remap_pfn_range says it should only be
     63	 * called when the mm semaphore is held
     64	 */
     65	if (remap_pfn_range(vma, vma->vm_start, p_buf >> PAGE_SHIFT, size,
     66			    vma->vm_page_prot))
     67		goto out;
     68	ret = 0;
     69out:
     70	return ret;
     71}
     72
     73static int mmapper_open(struct inode *inode, struct file *file)
     74{
     75	return 0;
     76}
     77
     78static int mmapper_release(struct inode *inode, struct file *file)
     79{
     80	return 0;
     81}
     82
     83static const struct file_operations mmapper_fops = {
     84	.owner		= THIS_MODULE,
     85	.read		= mmapper_read,
     86	.write		= mmapper_write,
     87	.unlocked_ioctl	= mmapper_ioctl,
     88	.mmap		= mmapper_mmap,
     89	.open		= mmapper_open,
     90	.release	= mmapper_release,
     91	.llseek		= default_llseek,
     92};
     93
     94/*
     95 * No locking needed - only used (and modified) by below initcall and exitcall.
     96 */
     97static struct miscdevice mmapper_dev = {
     98	.minor		= MISC_DYNAMIC_MINOR,
     99	.name		= "mmapper",
    100	.fops		= &mmapper_fops
    101};
    102
    103static int __init mmapper_init(void)
    104{
    105	int err;
    106
    107	printk(KERN_INFO "Mapper v0.1\n");
    108
    109	v_buf = (char *) find_iomem("mmapper", &mmapper_size);
    110	if (mmapper_size == 0) {
    111		printk(KERN_ERR "mmapper_init - find_iomem failed\n");
    112		return -ENODEV;
    113	}
    114	p_buf = __pa(v_buf);
    115
    116	err = misc_register(&mmapper_dev);
    117	if (err) {
    118		printk(KERN_ERR "mmapper - misc_register failed, err = %d\n",
    119		       err);
    120		return err;
    121	}
    122	return 0;
    123}
    124
    125static void mmapper_exit(void)
    126{
    127	misc_deregister(&mmapper_dev);
    128}
    129
    130module_init(mmapper_init);
    131module_exit(mmapper_exit);
    132
    133MODULE_AUTHOR("Greg Lonnon <glonnon@ridgerun.com>");
    134MODULE_DESCRIPTION("DSPLinux simulator mmapper driver");
    135MODULE_LICENSE("GPL");