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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n_null.c (1372B)

      1// SPDX-License-Identifier: GPL-2.0
      2#include <linux/types.h>
      3#include <linux/errno.h>
      4#include <linux/tty.h>
      5#include <linux/module.h>
      6
      7/*
      8 *  n_null.c - Null line discipline used in the failure path
      9 *
     10 *  Copyright (C) Intel 2017
     11 */
     12
     13static int n_null_open(struct tty_struct *tty)
     14{
     15	return 0;
     16}
     17
     18static void n_null_close(struct tty_struct *tty)
     19{
     20}
     21
     22static ssize_t n_null_read(struct tty_struct *tty, struct file *file,
     23			   unsigned char *buf, size_t nr,
     24			   void **cookie, unsigned long offset)
     25{
     26	return -EOPNOTSUPP;
     27}
     28
     29static ssize_t n_null_write(struct tty_struct *tty, struct file *file,
     30			    const unsigned char *buf, size_t nr)
     31{
     32	return -EOPNOTSUPP;
     33}
     34
     35static void n_null_receivebuf(struct tty_struct *tty,
     36				 const unsigned char *cp, const char *fp,
     37				 int cnt)
     38{
     39}
     40
     41static struct tty_ldisc_ops null_ldisc = {
     42	.owner		=	THIS_MODULE,
     43	.num		=	N_NULL,
     44	.name		=	"n_null",
     45	.open		=	n_null_open,
     46	.close		=	n_null_close,
     47	.read		=	n_null_read,
     48	.write		=	n_null_write,
     49	.receive_buf	=	n_null_receivebuf
     50};
     51
     52static int __init n_null_init(void)
     53{
     54	BUG_ON(tty_register_ldisc(&null_ldisc));
     55	return 0;
     56}
     57
     58static void __exit n_null_exit(void)
     59{
     60	tty_unregister_ldisc(&null_ldisc);
     61}
     62
     63module_init(n_null_init);
     64module_exit(n_null_exit);
     65
     66MODULE_LICENSE("GPL");
     67MODULE_AUTHOR("Alan Cox");
     68MODULE_ALIAS_LDISC(N_NULL);
     69MODULE_DESCRIPTION("Null ldisc driver");