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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sclp_ctl.c (2598B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * IOCTL interface for SCLP
      4 *
      5 * Copyright IBM Corp. 2012
      6 *
      7 * Author: Michael Holzheu <holzheu@linux.vnet.ibm.com>
      8 */
      9
     10#include <linux/compat.h>
     11#include <linux/uaccess.h>
     12#include <linux/miscdevice.h>
     13#include <linux/gfp.h>
     14#include <linux/init.h>
     15#include <linux/ioctl.h>
     16#include <linux/fs.h>
     17#include <asm/sclp_ctl.h>
     18#include <asm/sclp.h>
     19
     20#include "sclp.h"
     21
     22/*
     23 * Supported command words
     24 */
     25static unsigned int sclp_ctl_sccb_wlist[] = {
     26	0x00400002,
     27	0x00410002,
     28};
     29
     30/*
     31 * Check if command word is supported
     32 */
     33static int sclp_ctl_cmdw_supported(unsigned int cmdw)
     34{
     35	int i;
     36
     37	for (i = 0; i < ARRAY_SIZE(sclp_ctl_sccb_wlist); i++) {
     38		if (cmdw == sclp_ctl_sccb_wlist[i])
     39			return 1;
     40	}
     41	return 0;
     42}
     43
     44static void __user *u64_to_uptr(u64 value)
     45{
     46	if (is_compat_task())
     47		return compat_ptr(value);
     48	else
     49		return (void __user *)(unsigned long)value;
     50}
     51
     52/*
     53 * Start SCLP request
     54 */
     55static int sclp_ctl_ioctl_sccb(void __user *user_area)
     56{
     57	struct sclp_ctl_sccb ctl_sccb;
     58	struct sccb_header *sccb;
     59	unsigned long copied;
     60	int rc;
     61
     62	if (copy_from_user(&ctl_sccb, user_area, sizeof(ctl_sccb)))
     63		return -EFAULT;
     64	if (!sclp_ctl_cmdw_supported(ctl_sccb.cmdw))
     65		return -EOPNOTSUPP;
     66	sccb = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
     67	if (!sccb)
     68		return -ENOMEM;
     69	copied = PAGE_SIZE -
     70		copy_from_user(sccb, u64_to_uptr(ctl_sccb.sccb), PAGE_SIZE);
     71	if (offsetof(struct sccb_header, length) +
     72	    sizeof(sccb->length) > copied || sccb->length > copied) {
     73		rc = -EFAULT;
     74		goto out_free;
     75	}
     76	if (sccb->length < 8) {
     77		rc = -EINVAL;
     78		goto out_free;
     79	}
     80	rc = sclp_sync_request(ctl_sccb.cmdw, sccb);
     81	if (rc)
     82		goto out_free;
     83	if (copy_to_user(u64_to_uptr(ctl_sccb.sccb), sccb, sccb->length))
     84		rc = -EFAULT;
     85out_free:
     86	free_page((unsigned long) sccb);
     87	return rc;
     88}
     89
     90/*
     91 * SCLP SCCB ioctl function
     92 */
     93static long sclp_ctl_ioctl(struct file *filp, unsigned int cmd,
     94			   unsigned long arg)
     95{
     96	void __user *argp;
     97
     98	if (is_compat_task())
     99		argp = compat_ptr(arg);
    100	else
    101		argp = (void __user *) arg;
    102	switch (cmd) {
    103	case SCLP_CTL_SCCB:
    104		return sclp_ctl_ioctl_sccb(argp);
    105	default: /* unknown ioctl number */
    106		return -ENOTTY;
    107	}
    108}
    109
    110/*
    111 * File operations
    112 */
    113static const struct file_operations sclp_ctl_fops = {
    114	.owner = THIS_MODULE,
    115	.open = nonseekable_open,
    116	.unlocked_ioctl = sclp_ctl_ioctl,
    117	.compat_ioctl = sclp_ctl_ioctl,
    118	.llseek = no_llseek,
    119};
    120
    121/*
    122 * Misc device definition
    123 */
    124static struct miscdevice sclp_ctl_device = {
    125	.minor = MISC_DYNAMIC_MINOR,
    126	.name = "sclp",
    127	.fops = &sclp_ctl_fops,
    128};
    129builtin_misc_device(sclp_ctl_device);