blob: 82e6a6b253ebbbf9ddc8cbf3f7991fba90416340 [file] [log] [blame]
Christian Borntraeger6b979de2005-06-25 14:55:32 -07001/*
2 * Copyright (C) 2004,2005 IBM Corporation
Christian Borntraeger45af3af2006-09-20 15:59:24 +02003 * Interface implementation for communication with the z/VM control program
Christian Borntraeger6b979de2005-06-25 14:55:32 -07004 * Author(s): Christian Borntraeger <cborntra@de.ibm.com>
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
14#include <linux/fs.h>
15#include <linux/init.h>
16#include <linux/kernel.h>
17#include <linux/miscdevice.h>
18#include <linux/module.h>
19#include <asm/cpcmd.h>
20#include <asm/debug.h>
21#include <asm/uaccess.h>
22#include "vmcp.h"
23
24MODULE_LICENSE("GPL");
25MODULE_AUTHOR("Christian Borntraeger <cborntra@de.ibm.com>");
26MODULE_DESCRIPTION("z/VM CP interface");
27
28static debug_info_t *vmcp_debug;
29
30static int vmcp_open(struct inode *inode, struct file *file)
31{
32 struct vmcp_session *session;
33
34 if (!capable(CAP_SYS_ADMIN))
35 return -EPERM;
36
37 session = kmalloc(sizeof(*session), GFP_KERNEL);
38 if (!session)
39 return -ENOMEM;
40 session->bufsize = PAGE_SIZE;
41 session->response = NULL;
42 session->resp_size = 0;
43 init_MUTEX(&session->mutex);
44 file->private_data = session;
45 return nonseekable_open(inode, file);
46}
47
48static int vmcp_release(struct inode *inode, struct file *file)
49{
50 struct vmcp_session *session;
51
52 session = (struct vmcp_session *)file->private_data;
53 file->private_data = NULL;
54 free_pages((unsigned long)session->response, get_order(session->bufsize));
55 kfree(session);
56 return 0;
57}
58
59static ssize_t
60vmcp_read(struct file *file, char __user * buff, size_t count, loff_t * ppos)
61{
62 size_t tocopy;
63 struct vmcp_session *session;
64
65 session = (struct vmcp_session *)file->private_data;
66 if (down_interruptible(&session->mutex))
67 return -ERESTARTSYS;
68 if (!session->response) {
69 up(&session->mutex);
70 return 0;
71 }
72 if (*ppos > session->resp_size) {
73 up(&session->mutex);
74 return 0;
75 }
76 tocopy = min(session->resp_size - (size_t) (*ppos), count);
77 tocopy = min(tocopy,session->bufsize - (size_t) (*ppos));
78
79 if (copy_to_user(buff, session->response + (*ppos), tocopy)) {
80 up(&session->mutex);
81 return -EFAULT;
82 }
83 up(&session->mutex);
84 *ppos += tocopy;
85 return tocopy;
86}
87
88static ssize_t
89vmcp_write(struct file *file, const char __user * buff, size_t count,
90 loff_t * ppos)
91{
92 char *cmd;
93 struct vmcp_session *session;
94
95 if (count > 240)
96 return -EINVAL;
97 cmd = kmalloc(count + 1, GFP_KERNEL);
98 if (!cmd)
99 return -ENOMEM;
100 if (copy_from_user(cmd, buff, count)) {
101 kfree(cmd);
102 return -EFAULT;
103 }
104 cmd[count] = '\0';
105 session = (struct vmcp_session *)file->private_data;
Christian Borntraegera5da8662005-11-07 00:59:12 -0800106 if (down_interruptible(&session->mutex)) {
107 kfree(cmd);
Christian Borntraeger6b979de2005-06-25 14:55:32 -0700108 return -ERESTARTSYS;
Christian Borntraegera5da8662005-11-07 00:59:12 -0800109 }
Christian Borntraeger6b979de2005-06-25 14:55:32 -0700110 if (!session->response)
111 session->response = (char *)__get_free_pages(GFP_KERNEL
112 | __GFP_REPEAT | GFP_DMA,
113 get_order(session->bufsize));
114 if (!session->response) {
115 up(&session->mutex);
116 kfree(cmd);
117 return -ENOMEM;
118 }
119 debug_text_event(vmcp_debug, 1, cmd);
Christian Borntraegerbf3dbdc2007-01-09 10:19:03 +0100120 session->resp_size = cpcmd(cmd, session->response,
Christian Borntraeger3e5ea092005-07-27 11:45:06 -0700121 session->bufsize,
122 &session->resp_code);
Christian Borntraeger6b979de2005-06-25 14:55:32 -0700123 up(&session->mutex);
124 kfree(cmd);
125 *ppos = 0; /* reset the file pointer after a command */
126 return count;
127}
128
129
130/*
131 * These ioctls are available, as the semantics of the diagnose 8 call
132 * does not fit very well into a Linux call. Diagnose X'08' is described in
133 * CP Programming Services SC24-6084-00
134 *
135 * VMCP_GETCODE: gives the CP return code back to user space
136 * VMCP_SETBUF: sets the response buffer for the next write call. diagnose 8
137 * expects adjacent pages in real storage and to make matters worse, we
138 * dont know the size of the response. Therefore we default to PAGESIZE and
139 * let userspace to change the response size, if userspace expects a bigger
140 * response
141 */
142static long vmcp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
143{
144 struct vmcp_session *session;
145 int temp;
146
147 session = (struct vmcp_session *)file->private_data;
148 if (down_interruptible(&session->mutex))
149 return -ERESTARTSYS;
150 switch (cmd) {
151 case VMCP_GETCODE:
152 temp = session->resp_code;
153 up(&session->mutex);
154 return put_user(temp, (int __user *)arg);
155 case VMCP_SETBUF:
156 free_pages((unsigned long)session->response,
157 get_order(session->bufsize));
158 session->response=NULL;
159 temp = get_user(session->bufsize, (int __user *)arg);
160 if (get_order(session->bufsize) > 8) {
161 session->bufsize = PAGE_SIZE;
162 temp = -EINVAL;
163 }
164 up(&session->mutex);
165 return temp;
166 case VMCP_GETSIZE:
167 temp = session->resp_size;
168 up(&session->mutex);
169 return put_user(temp, (int __user *)arg);
170 default:
171 up(&session->mutex);
172 return -ENOIOCTLCMD;
173 }
174}
175
Arjan van de Vend54b1fd2007-02-12 00:55:34 -0800176static const struct file_operations vmcp_fops = {
Christian Borntraeger6b979de2005-06-25 14:55:32 -0700177 .owner = THIS_MODULE,
Robert P. J. Dayd197e692007-07-10 11:24:07 +0200178 .open = vmcp_open,
179 .release = vmcp_release,
180 .read = vmcp_read,
181 .write = vmcp_write,
182 .unlocked_ioctl = vmcp_ioctl,
183 .compat_ioctl = vmcp_ioctl
Christian Borntraeger6b979de2005-06-25 14:55:32 -0700184};
185
186static struct miscdevice vmcp_dev = {
187 .name = "vmcp",
188 .minor = MISC_DYNAMIC_MINOR,
189 .fops = &vmcp_fops,
190};
191
192static int __init vmcp_init(void)
193{
194 int ret;
195
196 if (!MACHINE_IS_VM) {
197 printk(KERN_WARNING
198 "z/VM CP interface is only available under z/VM\n");
199 return -ENODEV;
200 }
201 ret = misc_register(&vmcp_dev);
202 if (!ret)
203 printk(KERN_INFO "z/VM CP interface loaded\n");
204 else
205 printk(KERN_WARNING
206 "z/VM CP interface not loaded. Could not register misc device.\n");
Michael Holzheu66a464d2005-06-25 14:55:33 -0700207 vmcp_debug = debug_register("vmcp", 1, 1, 240);
Christian Borntraeger6b979de2005-06-25 14:55:32 -0700208 debug_register_view(vmcp_debug, &debug_hex_ascii_view);
209 return ret;
210}
211
212static void __exit vmcp_exit(void)
213{
214 WARN_ON(misc_deregister(&vmcp_dev) != 0);
215 debug_unregister(vmcp_debug);
216 printk(KERN_INFO "z/VM CP interface unloaded.\n");
217}
218
219module_init(vmcp_init);
220module_exit(vmcp_exit);