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authorChristian Borntraeger <cborntra@de.ibm.com>2005-06-25 17:55:32 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-25 19:24:37 -0400
commit6b979de395c7e1b7e59f74a870e1d1911853eccb (patch)
tree82502e9e93c977b0f812d017f5d8d4e12436c6c8 /drivers/s390/char/vmcp.c
parent77fa22450de00d535de2cc8be653983560828000 (diff)
[PATCH] s390: add vmcp interface
Add interface to issue VM control program commands. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers/s390/char/vmcp.c')
-rw-r--r--drivers/s390/char/vmcp.c219
1 files changed, 219 insertions, 0 deletions
diff --git a/drivers/s390/char/vmcp.c b/drivers/s390/char/vmcp.c
new file mode 100644
index 000000000000..dfbbf235ca2b
--- /dev/null
+++ b/drivers/s390/char/vmcp.c
@@ -0,0 +1,219 @@
1/*
2 * Copyright (C) 2004,2005 IBM Corporation
3 * Interface implementation for communication with the v/VM control program
4 * 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;
106 if (down_interruptible(&session->mutex))
107 return -ERESTARTSYS;
108 if (!session->response)
109 session->response = (char *)__get_free_pages(GFP_KERNEL
110 | __GFP_REPEAT | GFP_DMA,
111 get_order(session->bufsize));
112 if (!session->response) {
113 up(&session->mutex);
114 kfree(cmd);
115 return -ENOMEM;
116 }
117 debug_text_event(vmcp_debug, 1, cmd);
118 session->resp_size = cpcmd(cmd, session->response,
119 session->bufsize,
120 &session->resp_code);
121 up(&session->mutex);
122 kfree(cmd);
123 *ppos = 0; /* reset the file pointer after a command */
124 return count;
125}
126
127
128/*
129 * These ioctls are available, as the semantics of the diagnose 8 call
130 * does not fit very well into a Linux call. Diagnose X'08' is described in
131 * CP Programming Services SC24-6084-00
132 *
133 * VMCP_GETCODE: gives the CP return code back to user space
134 * VMCP_SETBUF: sets the response buffer for the next write call. diagnose 8
135 * expects adjacent pages in real storage and to make matters worse, we
136 * dont know the size of the response. Therefore we default to PAGESIZE and
137 * let userspace to change the response size, if userspace expects a bigger
138 * response
139 */
140static long vmcp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
141{
142 struct vmcp_session *session;
143 int temp;
144
145 session = (struct vmcp_session *)file->private_data;
146 if (down_interruptible(&session->mutex))
147 return -ERESTARTSYS;
148 switch (cmd) {
149 case VMCP_GETCODE:
150 temp = session->resp_code;
151 up(&session->mutex);
152 return put_user(temp, (int __user *)arg);
153 case VMCP_SETBUF:
154 free_pages((unsigned long)session->response,
155 get_order(session->bufsize));
156 session->response=NULL;
157 temp = get_user(session->bufsize, (int __user *)arg);
158 if (get_order(session->bufsize) > 8) {
159 session->bufsize = PAGE_SIZE;
160 temp = -EINVAL;
161 }
162 up(&session->mutex);
163 return temp;
164 case VMCP_GETSIZE:
165 temp = session->resp_size;
166 up(&session->mutex);
167 return put_user(temp, (int __user *)arg);
168 default:
169 up(&session->mutex);
170 return -ENOIOCTLCMD;
171 }
172}
173
174static struct file_operations vmcp_fops = {
175 .owner = THIS_MODULE,
176 .open = &vmcp_open,
177 .release = &vmcp_release,
178 .read = &vmcp_read,
179 .llseek = &no_llseek,
180 .write = &vmcp_write,
181 .unlocked_ioctl = &vmcp_ioctl,
182 .compat_ioctl = &vmcp_ioctl
183};
184
185static struct miscdevice vmcp_dev = {
186 .name = "vmcp",
187 .minor = MISC_DYNAMIC_MINOR,
188 .fops = &vmcp_fops,
189};
190
191static int __init vmcp_init(void)
192{
193 int ret;
194
195 if (!MACHINE_IS_VM) {
196 printk(KERN_WARNING
197 "z/VM CP interface is only available under z/VM\n");
198 return -ENODEV;
199 }
200 ret = misc_register(&vmcp_dev);
201 if (!ret)
202 printk(KERN_INFO "z/VM CP interface loaded\n");
203 else
204 printk(KERN_WARNING
205 "z/VM CP interface not loaded. Could not register misc device.\n");
206 vmcp_debug = debug_register("vmcp", 0, 1, 240);
207 debug_register_view(vmcp_debug, &debug_hex_ascii_view);
208 return ret;
209}
210
211static void __exit vmcp_exit(void)
212{
213 WARN_ON(misc_deregister(&vmcp_dev) != 0);
214 debug_unregister(vmcp_debug);
215 printk(KERN_INFO "z/VM CP interface unloaded.\n");
216}
217
218module_init(vmcp_init);
219module_exit(vmcp_exit);