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);