Commit | Line | Data |
---|---|---|
6b979de3 | 1 | /* |
d9d119f1 | 2 | * Copyright IBM Corp. 2004,2007 |
45af3af8 | 3 | * Interface implementation for communication with the z/VM control program |
d9d119f1 | 4 | * Author(s): Christian Borntraeger <borntraeger@de.ibm.com> |
6b979de3 CB |
5 | * |
6 | * | |
7 | * z/VMs CP offers the possibility to issue commands via the diagnose code 8 | |
8 | * this driver implements a character device that issues these commands and | |
9 | * returns the answer of CP. | |
10 | ||
11 | * The idea of this driver is based on cpint from Neale Ferguson and #CP in CMS | |
12 | */ | |
13 | ||
8988e58f CB |
14 | #define KMSG_COMPONENT "vmcp" |
15 | #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt | |
16 | ||
6b979de3 CB |
17 | #include <linux/fs.h> |
18 | #include <linux/init.h> | |
19 | #include <linux/kernel.h> | |
20 | #include <linux/miscdevice.h> | |
21 | #include <linux/module.h> | |
22 | #include <asm/cpcmd.h> | |
23 | #include <asm/debug.h> | |
24 | #include <asm/uaccess.h> | |
25 | #include "vmcp.h" | |
26 | ||
27 | MODULE_LICENSE("GPL"); | |
d9d119f1 | 28 | MODULE_AUTHOR("Christian Borntraeger <borntraeger@de.ibm.com>"); |
6b979de3 CB |
29 | MODULE_DESCRIPTION("z/VM CP interface"); |
30 | ||
31 | static debug_info_t *vmcp_debug; | |
32 | ||
33 | static int vmcp_open(struct inode *inode, struct file *file) | |
34 | { | |
35 | struct vmcp_session *session; | |
36 | ||
37 | if (!capable(CAP_SYS_ADMIN)) | |
38 | return -EPERM; | |
39 | ||
40 | session = kmalloc(sizeof(*session), GFP_KERNEL); | |
41 | if (!session) | |
42 | return -ENOMEM; | |
6c111d88 | 43 | |
6b979de3 CB |
44 | session->bufsize = PAGE_SIZE; |
45 | session->response = NULL; | |
46 | session->resp_size = 0; | |
d9d119f1 | 47 | mutex_init(&session->mutex); |
6b979de3 CB |
48 | file->private_data = session; |
49 | return nonseekable_open(inode, file); | |
50 | } | |
51 | ||
52 | static int vmcp_release(struct inode *inode, struct file *file) | |
53 | { | |
54 | struct vmcp_session *session; | |
55 | ||
56 | session = (struct vmcp_session *)file->private_data; | |
57 | file->private_data = NULL; | |
58 | free_pages((unsigned long)session->response, get_order(session->bufsize)); | |
59 | kfree(session); | |
60 | return 0; | |
61 | } | |
62 | ||
63 | static ssize_t | |
d9d119f1 | 64 | vmcp_read(struct file *file, char __user *buff, size_t count, loff_t *ppos) |
6b979de3 | 65 | { |
7785857a AM |
66 | ssize_t ret; |
67 | size_t size; | |
6b979de3 CB |
68 | struct vmcp_session *session; |
69 | ||
7785857a | 70 | session = file->private_data; |
d9d119f1 | 71 | if (mutex_lock_interruptible(&session->mutex)) |
6b979de3 CB |
72 | return -ERESTARTSYS; |
73 | if (!session->response) { | |
d9d119f1 | 74 | mutex_unlock(&session->mutex); |
6b979de3 CB |
75 | return 0; |
76 | } | |
7785857a AM |
77 | size = min_t(size_t, session->resp_size, session->bufsize); |
78 | ret = simple_read_from_buffer(buff, count, ppos, | |
79 | session->response, size); | |
6b979de3 | 80 | |
d9d119f1 | 81 | mutex_unlock(&session->mutex); |
7785857a AM |
82 | |
83 | return ret; | |
6b979de3 CB |
84 | } |
85 | ||
86 | static ssize_t | |
d9d119f1 CB |
87 | vmcp_write(struct file *file, const char __user *buff, size_t count, |
88 | loff_t *ppos) | |
6b979de3 CB |
89 | { |
90 | char *cmd; | |
91 | struct vmcp_session *session; | |
92 | ||
93 | if (count > 240) | |
94 | return -EINVAL; | |
95 | cmd = kmalloc(count + 1, GFP_KERNEL); | |
96 | if (!cmd) | |
97 | return -ENOMEM; | |
98 | if (copy_from_user(cmd, buff, count)) { | |
99 | kfree(cmd); | |
100 | return -EFAULT; | |
101 | } | |
102 | cmd[count] = '\0'; | |
103 | session = (struct vmcp_session *)file->private_data; | |
d9d119f1 | 104 | if (mutex_lock_interruptible(&session->mutex)) { |
a5da866f | 105 | kfree(cmd); |
6b979de3 | 106 | return -ERESTARTSYS; |
a5da866f | 107 | } |
6b979de3 CB |
108 | if (!session->response) |
109 | session->response = (char *)__get_free_pages(GFP_KERNEL | |
d9d119f1 | 110 | | __GFP_REPEAT | GFP_DMA, |
6b979de3 CB |
111 | get_order(session->bufsize)); |
112 | if (!session->response) { | |
d9d119f1 | 113 | mutex_unlock(&session->mutex); |
6b979de3 CB |
114 | kfree(cmd); |
115 | return -ENOMEM; | |
116 | } | |
117 | debug_text_event(vmcp_debug, 1, cmd); | |
d9d119f1 CB |
118 | session->resp_size = cpcmd(cmd, session->response, session->bufsize, |
119 | &session->resp_code); | |
120 | mutex_unlock(&session->mutex); | |
6b979de3 CB |
121 | kfree(cmd); |
122 | *ppos = 0; /* reset the file pointer after a command */ | |
123 | return count; | |
124 | } | |
125 | ||
126 | ||
127 | /* | |
128 | * These ioctls are available, as the semantics of the diagnose 8 call | |
129 | * does not fit very well into a Linux call. Diagnose X'08' is described in | |
130 | * CP Programming Services SC24-6084-00 | |
131 | * | |
132 | * VMCP_GETCODE: gives the CP return code back to user space | |
133 | * VMCP_SETBUF: sets the response buffer for the next write call. diagnose 8 | |
134 | * expects adjacent pages in real storage and to make matters worse, we | |
135 | * dont know the size of the response. Therefore we default to PAGESIZE and | |
136 | * let userspace to change the response size, if userspace expects a bigger | |
137 | * response | |
138 | */ | |
139 | static long vmcp_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
140 | { | |
141 | struct vmcp_session *session; | |
142 | int temp; | |
143 | ||
144 | session = (struct vmcp_session *)file->private_data; | |
d9d119f1 | 145 | if (mutex_lock_interruptible(&session->mutex)) |
6b979de3 CB |
146 | return -ERESTARTSYS; |
147 | switch (cmd) { | |
148 | case VMCP_GETCODE: | |
149 | temp = session->resp_code; | |
d9d119f1 | 150 | mutex_unlock(&session->mutex); |
6b979de3 CB |
151 | return put_user(temp, (int __user *)arg); |
152 | case VMCP_SETBUF: | |
153 | free_pages((unsigned long)session->response, | |
154 | get_order(session->bufsize)); | |
155 | session->response=NULL; | |
156 | temp = get_user(session->bufsize, (int __user *)arg); | |
157 | if (get_order(session->bufsize) > 8) { | |
158 | session->bufsize = PAGE_SIZE; | |
159 | temp = -EINVAL; | |
160 | } | |
d9d119f1 | 161 | mutex_unlock(&session->mutex); |
6b979de3 CB |
162 | return temp; |
163 | case VMCP_GETSIZE: | |
164 | temp = session->resp_size; | |
d9d119f1 | 165 | mutex_unlock(&session->mutex); |
6b979de3 CB |
166 | return put_user(temp, (int __user *)arg); |
167 | default: | |
d9d119f1 | 168 | mutex_unlock(&session->mutex); |
6b979de3 CB |
169 | return -ENOIOCTLCMD; |
170 | } | |
171 | } | |
172 | ||
d54b1fdb | 173 | static const struct file_operations vmcp_fops = { |
6b979de3 | 174 | .owner = THIS_MODULE, |
d197e692 RD |
175 | .open = vmcp_open, |
176 | .release = vmcp_release, | |
177 | .read = vmcp_read, | |
178 | .write = vmcp_write, | |
179 | .unlocked_ioctl = vmcp_ioctl, | |
d9d119f1 | 180 | .compat_ioctl = vmcp_ioctl, |
6b979de3 CB |
181 | }; |
182 | ||
183 | static struct miscdevice vmcp_dev = { | |
184 | .name = "vmcp", | |
185 | .minor = MISC_DYNAMIC_MINOR, | |
186 | .fops = &vmcp_fops, | |
187 | }; | |
188 | ||
189 | static int __init vmcp_init(void) | |
190 | { | |
191 | int ret; | |
192 | ||
193 | if (!MACHINE_IS_VM) { | |
8988e58f CB |
194 | pr_warning("The z/VM CP interface device driver cannot be " |
195 | "loaded without z/VM\n"); | |
6b979de3 CB |
196 | return -ENODEV; |
197 | } | |
a44008f2 | 198 | |
66a464db | 199 | vmcp_debug = debug_register("vmcp", 1, 1, 240); |
a44008f2 | 200 | if (!vmcp_debug) |
d9d119f1 | 201 | return -ENOMEM; |
a44008f2 | 202 | |
d9d119f1 CB |
203 | ret = debug_register_view(vmcp_debug, &debug_hex_ascii_view); |
204 | if (ret) { | |
d9d119f1 CB |
205 | debug_unregister(vmcp_debug); |
206 | return ret; | |
207 | } | |
a44008f2 | 208 | |
d9d119f1 CB |
209 | ret = misc_register(&vmcp_dev); |
210 | if (ret) { | |
d9d119f1 CB |
211 | debug_unregister(vmcp_debug); |
212 | return ret; | |
213 | } | |
a44008f2 | 214 | |
d9d119f1 | 215 | return 0; |
6b979de3 CB |
216 | } |
217 | ||
218 | static void __exit vmcp_exit(void) | |
219 | { | |
d9d119f1 | 220 | misc_deregister(&vmcp_dev); |
6b979de3 | 221 | debug_unregister(vmcp_debug); |
6b979de3 CB |
222 | } |
223 | ||
224 | module_init(vmcp_init); | |
225 | module_exit(vmcp_exit); |