1/*
2 * IOCTL interface for SCLP
3 *
4 * Copyright IBM Corp. 2012
5 *
6 * Author: Michael Holzheu <holzheu@linux.vnet.ibm.com>
7 */
8
9#include <linux/compat.h>
10#include <linux/uaccess.h>
11#include <linux/miscdevice.h>
12#include <linux/gfp.h>
13#include <linux/module.h>
14#include <linux/ioctl.h>
15#include <linux/fs.h>
16#include <asm/compat.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	int rc;
60
61	if (copy_from_user(&ctl_sccb, user_area, sizeof(ctl_sccb)))
62		return -EFAULT;
63	if (!sclp_ctl_cmdw_supported(ctl_sccb.cmdw))
64		return -EOPNOTSUPP;
65	sccb = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
66	if (!sccb)
67		return -ENOMEM;
68	if (copy_from_user(sccb, u64_to_uptr(ctl_sccb.sccb), sizeof(*sccb))) {
69		rc = -EFAULT;
70		goto out_free;
71	}
72	if (sccb->length > PAGE_SIZE || sccb->length < 8)
73		return -EINVAL;
74	if (copy_from_user(sccb, u64_to_uptr(ctl_sccb.sccb), sccb->length)) {
75		rc = -EFAULT;
76		goto out_free;
77	}
78	rc = sclp_sync_request(ctl_sccb.cmdw, sccb);
79	if (rc)
80		goto out_free;
81	if (copy_to_user(u64_to_uptr(ctl_sccb.sccb), sccb, sccb->length))
82		rc = -EFAULT;
83out_free:
84	free_page((unsigned long) sccb);
85	return rc;
86}
87
88/*
89 * SCLP SCCB ioctl function
90 */
91static long sclp_ctl_ioctl(struct file *filp, unsigned int cmd,
92			   unsigned long arg)
93{
94	void __user *argp;
95
96	if (is_compat_task())
97		argp = compat_ptr(arg);
98	else
99		argp = (void __user *) arg;
100	switch (cmd) {
101	case SCLP_CTL_SCCB:
102		return sclp_ctl_ioctl_sccb(argp);
103	default: /* unknown ioctl number */
104		return -ENOTTY;
105	}
106}
107
108/*
109 * File operations
110 */
111static const struct file_operations sclp_ctl_fops = {
112	.owner = THIS_MODULE,
113	.open = nonseekable_open,
114	.unlocked_ioctl = sclp_ctl_ioctl,
115	.compat_ioctl = sclp_ctl_ioctl,
116	.llseek = no_llseek,
117};
118
119/*
120 * Misc device definition
121 */
122static struct miscdevice sclp_ctl_device = {
123	.minor = MISC_DYNAMIC_MINOR,
124	.name = "sclp",
125	.fops = &sclp_ctl_fops,
126};
127
128/*
129 * Register sclp_ctl misc device
130 */
131static int __init sclp_ctl_init(void)
132{
133	return misc_register(&sclp_ctl_device);
134}
135module_init(sclp_ctl_init);
136
137/*
138 * Deregister sclp_ctl misc device
139 */
140static void __exit sclp_ctl_exit(void)
141{
142	misc_deregister(&sclp_ctl_device);
143}
144module_exit(sclp_ctl_exit);
145