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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inttype-example.c (3846B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Sample kfifo int type implementation
      4 *
      5 * Copyright (C) 2010 Stefani Seibold <stefani@seibold.net>
      6 */
      7
      8#include <linux/init.h>
      9#include <linux/module.h>
     10#include <linux/proc_fs.h>
     11#include <linux/mutex.h>
     12#include <linux/kfifo.h>
     13
     14/*
     15 * This module shows how to create a int type fifo.
     16 */
     17
     18/* fifo size in elements (ints) */
     19#define FIFO_SIZE	32
     20
     21/* name of the proc entry */
     22#define	PROC_FIFO	"int-fifo"
     23
     24/* lock for procfs read access */
     25static DEFINE_MUTEX(read_access);
     26
     27/* lock for procfs write access */
     28static DEFINE_MUTEX(write_access);
     29
     30/*
     31 * define DYNAMIC in this example for a dynamically allocated fifo.
     32 *
     33 * Otherwise the fifo storage will be a part of the fifo structure.
     34 */
     35#if 0
     36#define DYNAMIC
     37#endif
     38
     39#ifdef DYNAMIC
     40static DECLARE_KFIFO_PTR(test, int);
     41#else
     42static DEFINE_KFIFO(test, int, FIFO_SIZE);
     43#endif
     44
     45static const int expected_result[FIFO_SIZE] = {
     46	 3,  4,  5,  6,  7,  8,  9,  0,
     47	 1, 20, 21, 22, 23, 24, 25, 26,
     48	27, 28, 29, 30, 31, 32, 33, 34,
     49	35, 36, 37, 38, 39, 40, 41, 42,
     50};
     51
     52static int __init testfunc(void)
     53{
     54	int		buf[6];
     55	int		i, j;
     56	unsigned int	ret;
     57
     58	printk(KERN_INFO "int fifo test start\n");
     59
     60	/* put values into the fifo */
     61	for (i = 0; i != 10; i++)
     62		kfifo_put(&test, i);
     63
     64	/* show the number of used elements */
     65	printk(KERN_INFO "fifo len: %u\n", kfifo_len(&test));
     66
     67	/* get max of 2 elements from the fifo */
     68	ret = kfifo_out(&test, buf, 2);
     69	printk(KERN_INFO "ret: %d\n", ret);
     70	/* and put it back to the end of the fifo */
     71	ret = kfifo_in(&test, buf, ret);
     72	printk(KERN_INFO "ret: %d\n", ret);
     73
     74	/* skip first element of the fifo */
     75	printk(KERN_INFO "skip 1st element\n");
     76	kfifo_skip(&test);
     77
     78	/* put values into the fifo until is full */
     79	for (i = 20; kfifo_put(&test, i); i++)
     80		;
     81
     82	printk(KERN_INFO "queue len: %u\n", kfifo_len(&test));
     83
     84	/* show the first value without removing from the fifo */
     85	if (kfifo_peek(&test, &i))
     86		printk(KERN_INFO "%d\n", i);
     87
     88	/* check the correctness of all values in the fifo */
     89	j = 0;
     90	while (kfifo_get(&test, &i)) {
     91		printk(KERN_INFO "item = %d\n", i);
     92		if (i != expected_result[j++]) {
     93			printk(KERN_WARNING "value mismatch: test failed\n");
     94			return -EIO;
     95		}
     96	}
     97	if (j != ARRAY_SIZE(expected_result)) {
     98		printk(KERN_WARNING "size mismatch: test failed\n");
     99		return -EIO;
    100	}
    101	printk(KERN_INFO "test passed\n");
    102
    103	return 0;
    104}
    105
    106static ssize_t fifo_write(struct file *file, const char __user *buf,
    107						size_t count, loff_t *ppos)
    108{
    109	int ret;
    110	unsigned int copied;
    111
    112	if (mutex_lock_interruptible(&write_access))
    113		return -ERESTARTSYS;
    114
    115	ret = kfifo_from_user(&test, buf, count, &copied);
    116
    117	mutex_unlock(&write_access);
    118	if (ret)
    119		return ret;
    120
    121	return copied;
    122}
    123
    124static ssize_t fifo_read(struct file *file, char __user *buf,
    125						size_t count, loff_t *ppos)
    126{
    127	int ret;
    128	unsigned int copied;
    129
    130	if (mutex_lock_interruptible(&read_access))
    131		return -ERESTARTSYS;
    132
    133	ret = kfifo_to_user(&test, buf, count, &copied);
    134
    135	mutex_unlock(&read_access);
    136	if (ret)
    137		return ret;
    138
    139	return copied;
    140}
    141
    142static const struct proc_ops fifo_proc_ops = {
    143	.proc_read	= fifo_read,
    144	.proc_write	= fifo_write,
    145	.proc_lseek	= noop_llseek,
    146};
    147
    148static int __init example_init(void)
    149{
    150#ifdef DYNAMIC
    151	int ret;
    152
    153	ret = kfifo_alloc(&test, FIFO_SIZE, GFP_KERNEL);
    154	if (ret) {
    155		printk(KERN_ERR "error kfifo_alloc\n");
    156		return ret;
    157	}
    158#endif
    159	if (testfunc() < 0) {
    160#ifdef DYNAMIC
    161		kfifo_free(&test);
    162#endif
    163		return -EIO;
    164	}
    165
    166	if (proc_create(PROC_FIFO, 0, NULL, &fifo_proc_ops) == NULL) {
    167#ifdef DYNAMIC
    168		kfifo_free(&test);
    169#endif
    170		return -ENOMEM;
    171	}
    172	return 0;
    173}
    174
    175static void __exit example_exit(void)
    176{
    177	remove_proc_entry(PROC_FIFO, NULL);
    178#ifdef DYNAMIC
    179	kfifo_free(&test);
    180#endif
    181}
    182
    183module_init(example_init);
    184module_exit(example_exit);
    185MODULE_LICENSE("GPL");
    186MODULE_AUTHOR("Stefani Seibold <stefani@seibold.net>");