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);
130