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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bL_switcher_dummy_if.c (1381B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * arch/arm/common/bL_switcher_dummy_if.c -- b.L switcher dummy interface
      4 *
      5 * Created by:	Nicolas Pitre, November 2012
      6 * Copyright:	(C) 2012-2013  Linaro Limited
      7 *
      8 * Dummy interface to user space for debugging purpose only.
      9 */
     10
     11#include <linux/init.h>
     12#include <linux/module.h>
     13#include <linux/fs.h>
     14#include <linux/miscdevice.h>
     15#include <linux/uaccess.h>
     16#include <asm/bL_switcher.h>
     17
     18static ssize_t bL_switcher_write(struct file *file, const char __user *buf,
     19			size_t len, loff_t *pos)
     20{
     21	unsigned char val[3];
     22	unsigned int cpu, cluster;
     23	int ret;
     24
     25	pr_debug("%s\n", __func__);
     26
     27	if (len < 3)
     28		return -EINVAL;
     29
     30	if (copy_from_user(val, buf, 3))
     31		return -EFAULT;
     32
     33	/* format: <cpu#>,<cluster#> */
     34	if (val[0] < '0' || val[0] > '9' ||
     35	    val[1] != ',' ||
     36	    val[2] < '0' || val[2] > '1')
     37		return -EINVAL;
     38
     39	cpu = val[0] - '0';
     40	cluster = val[2] - '0';
     41	ret = bL_switch_request(cpu, cluster);
     42
     43	return ret ? : len;
     44}
     45
     46static const struct file_operations bL_switcher_fops = {
     47	.write		= bL_switcher_write,
     48	.owner	= THIS_MODULE,
     49};
     50
     51static struct miscdevice bL_switcher_device = {
     52	MISC_DYNAMIC_MINOR,
     53	"b.L_switcher",
     54	&bL_switcher_fops
     55};
     56module_misc_device(bL_switcher_device);
     57
     58MODULE_AUTHOR("Nicolas Pitre <nico@linaro.org>");
     59MODULE_LICENSE("GPL v2");
     60MODULE_DESCRIPTION("big.LITTLE switcher dummy user interface");