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 | */ |
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 | |
44 | static void __user *u64_to_uptr(u64 value) |
45 | { |
46 | if (is_compat_task()) |
47 | return compat_ptr(uptr: value); |
48 | else |
49 | return (void __user *)(unsigned long)value; |
50 | } |
51 | |
52 | /* |
53 | * Start SCLP request |
54 | */ |
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(to: &ctl_sccb, from: user_area, n: sizeof(ctl_sccb))) |
63 | return -EFAULT; |
64 | if (!sclp_ctl_cmdw_supported(cmdw: 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(to: sccb, from: u64_to_uptr(value: 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(command: ctl_sccb.cmdw, sccb); |
81 | if (rc) |
82 | goto out_free; |
83 | if (copy_to_user(to: u64_to_uptr(value: ctl_sccb.sccb), from: sccb, n: 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 | */ |
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(uptr: arg); |
100 | else |
101 | argp = (void __user *) arg; |
102 | switch (cmd) { |
103 | case SCLP_CTL_SCCB: |
104 | return sclp_ctl_ioctl_sccb(user_area: 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 | |