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 */
25 static unsigned int sclp_ctl_sccb_wlist[] = {
26 0x00400002,
27 0x00410002,
28 };
29
30 /*
31 * Check if command word is supported
32 */
sclp_ctl_cmdw_supported(unsigned int cmdw)33 static 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
u64_to_uptr(u64 value)44 static 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 */
sclp_ctl_ioctl_sccb(void __user * user_area)55 static 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;
85 out_free:
86 free_page((unsigned long) sccb);
87 return rc;
88 }
89
90 /*
91 * SCLP SCCB ioctl function
92 */
sclp_ctl_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)93 static 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 */
113 static 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 */
124 static struct miscdevice sclp_ctl_device = {
125 .minor = MISC_DYNAMIC_MINOR,
126 .name = "sclp",
127 .fops = &sclp_ctl_fops,
128 };
129 builtin_misc_device(sclp_ctl_device);
130