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1/*
2 * Copyright IBM Corp. 2004,2010
3 * Interface implementation for communication with the z/VM control program
4 *
5 * Author(s): Christian Borntraeger <borntraeger@de.ibm.com>
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/slab.h>
19#include <asm/compat.h>
20#include <asm/cpcmd.h>
21#include <asm/debug.h>
22#include <asm/uaccess.h>
23#include "vmcp.h"
24
25static debug_info_t *vmcp_debug;
26
27static int vmcp_open(struct inode *inode, struct file *file)
28{
29 struct vmcp_session *session;
30
31 if (!capable(CAP_SYS_ADMIN))
32 return -EPERM;
33
34 session = kmalloc(sizeof(*session), GFP_KERNEL);
35 if (!session)
36 return -ENOMEM;
37
38 session->bufsize = PAGE_SIZE;
39 session->response = NULL;
40 session->resp_size = 0;
41 mutex_init(&session->mutex);
42 file->private_data = session;
43 return nonseekable_open(inode, file);
44}
45
46static int vmcp_release(struct inode *inode, struct file *file)
47{
48 struct vmcp_session *session;
49
50 session = file->private_data;
51 file->private_data = NULL;
52 free_pages((unsigned long)session->response, get_order(session->bufsize));
53 kfree(session);
54 return 0;
55}
56
57static ssize_t
58vmcp_read(struct file *file, char __user *buff, size_t count, loff_t *ppos)
59{
60 ssize_t ret;
61 size_t size;
62 struct vmcp_session *session;
63
64 session = file->private_data;
65 if (mutex_lock_interruptible(&session->mutex))
66 return -ERESTARTSYS;
67 if (!session->response) {
68 mutex_unlock(&session->mutex);
69 return 0;
70 }
71 size = min_t(size_t, session->resp_size, session->bufsize);
72 ret = simple_read_from_buffer(buff, count, ppos,
73 session->response, size);
74
75 mutex_unlock(&session->mutex);
76
77 return ret;
78}
79
80static ssize_t
81vmcp_write(struct file *file, const char __user *buff, size_t count,
82 loff_t *ppos)
83{
84 char *cmd;
85 struct vmcp_session *session;
86
87 if (count > 240)
88 return -EINVAL;
89 cmd = kmalloc(count + 1, GFP_KERNEL);
90 if (!cmd)
91 return -ENOMEM;
92 if (copy_from_user(cmd, buff, count)) {
93 kfree(cmd);
94 return -EFAULT;
95 }
96 cmd[count] = '\0';
97 session = file->private_data;
98 if (mutex_lock_interruptible(&session->mutex)) {
99 kfree(cmd);
100 return -ERESTARTSYS;
101 }
102 if (!session->response)
103 session->response = (char *)__get_free_pages(GFP_KERNEL
104 | __GFP_REPEAT | GFP_DMA,
105 get_order(session->bufsize));
106 if (!session->response) {
107 mutex_unlock(&session->mutex);
108 kfree(cmd);
109 return -ENOMEM;
110 }
111 debug_text_event(vmcp_debug, 1, cmd);
112 session->resp_size = cpcmd(cmd, session->response, session->bufsize,
113 &session->resp_code);
114 mutex_unlock(&session->mutex);
115 kfree(cmd);
116 *ppos = 0; /* reset the file pointer after a command */
117 return count;
118}
119
120
121/*
122 * These ioctls are available, as the semantics of the diagnose 8 call
123 * does not fit very well into a Linux call. Diagnose X'08' is described in
124 * CP Programming Services SC24-6084-00
125 *
126 * VMCP_GETCODE: gives the CP return code back to user space
127 * VMCP_SETBUF: sets the response buffer for the next write call. diagnose 8
128 * expects adjacent pages in real storage and to make matters worse, we
129 * dont know the size of the response. Therefore we default to PAGESIZE and
130 * let userspace to change the response size, if userspace expects a bigger
131 * response
132 */
133static long vmcp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
134{
135 struct vmcp_session *session;
136 int __user *argp;
137 int temp;
138
139 session = file->private_data;
140 if (is_compat_task())
141 argp = compat_ptr(arg);
142 else
143 argp = (int __user *)arg;
144 if (mutex_lock_interruptible(&session->mutex))
145 return -ERESTARTSYS;
146 switch (cmd) {
147 case VMCP_GETCODE:
148 temp = session->resp_code;
149 mutex_unlock(&session->mutex);
150 return put_user(temp, argp);
151 case VMCP_SETBUF:
152 free_pages((unsigned long)session->response,
153 get_order(session->bufsize));
154 session->response=NULL;
155 temp = get_user(session->bufsize, argp);
156 if (get_order(session->bufsize) > 8) {
157 session->bufsize = PAGE_SIZE;
158 temp = -EINVAL;
159 }
160 mutex_unlock(&session->mutex);
161 return temp;
162 case VMCP_GETSIZE:
163 temp = session->resp_size;
164 mutex_unlock(&session->mutex);
165 return put_user(temp, argp);
166 default:
167 mutex_unlock(&session->mutex);
168 return -ENOIOCTLCMD;
169 }
170}
171
172static const struct file_operations vmcp_fops = {
173 .owner = THIS_MODULE,
174 .open = vmcp_open,
175 .release = vmcp_release,
176 .read = vmcp_read,
177 .write = vmcp_write,
178 .unlocked_ioctl = vmcp_ioctl,
179 .compat_ioctl = vmcp_ioctl,
180 .llseek = no_llseek,
181};
182
183static struct miscdevice vmcp_dev = {
184 .name = "vmcp",
185 .minor = MISC_DYNAMIC_MINOR,
186 .fops = &vmcp_fops,
187};
188
189static int __init vmcp_init(void)
190{
191 int ret;
192
193 if (!MACHINE_IS_VM)
194 return 0;
195
196 vmcp_debug = debug_register("vmcp", 1, 1, 240);
197 if (!vmcp_debug)
198 return -ENOMEM;
199
200 ret = debug_register_view(vmcp_debug, &debug_hex_ascii_view);
201 if (ret) {
202 debug_unregister(vmcp_debug);
203 return ret;
204 }
205
206 ret = misc_register(&vmcp_dev);
207 if (ret)
208 debug_unregister(vmcp_debug);
209 return ret;
210}
211device_initcall(vmcp_init);
1/*
2 * Copyright IBM Corp. 2004, 2010
3 * Interface implementation for communication with the z/VM control program
4 *
5 * Author(s): Christian Borntraeger <borntraeger@de.ibm.com>
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/compat.h>
17#include <linux/kernel.h>
18#include <linux/miscdevice.h>
19#include <linux/slab.h>
20#include <linux/export.h>
21#include <asm/compat.h>
22#include <asm/cpcmd.h>
23#include <asm/debug.h>
24#include <asm/uaccess.h>
25#include "vmcp.h"
26
27static debug_info_t *vmcp_debug;
28
29static int vmcp_open(struct inode *inode, struct file *file)
30{
31 struct vmcp_session *session;
32
33 if (!capable(CAP_SYS_ADMIN))
34 return -EPERM;
35
36 session = kmalloc(sizeof(*session), GFP_KERNEL);
37 if (!session)
38 return -ENOMEM;
39
40 session->bufsize = PAGE_SIZE;
41 session->response = NULL;
42 session->resp_size = 0;
43 mutex_init(&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 = 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 ssize_t ret;
63 size_t size;
64 struct vmcp_session *session;
65
66 session = file->private_data;
67 if (mutex_lock_interruptible(&session->mutex))
68 return -ERESTARTSYS;
69 if (!session->response) {
70 mutex_unlock(&session->mutex);
71 return 0;
72 }
73 size = min_t(size_t, session->resp_size, session->bufsize);
74 ret = simple_read_from_buffer(buff, count, ppos,
75 session->response, size);
76
77 mutex_unlock(&session->mutex);
78
79 return ret;
80}
81
82static ssize_t
83vmcp_write(struct file *file, const char __user *buff, size_t count,
84 loff_t *ppos)
85{
86 char *cmd;
87 struct vmcp_session *session;
88
89 if (count > 240)
90 return -EINVAL;
91 cmd = memdup_user_nul(buff, count);
92 if (IS_ERR(cmd))
93 return PTR_ERR(cmd);
94 session = file->private_data;
95 if (mutex_lock_interruptible(&session->mutex)) {
96 kfree(cmd);
97 return -ERESTARTSYS;
98 }
99 if (!session->response)
100 session->response = (char *)__get_free_pages(GFP_KERNEL
101 | __GFP_REPEAT | GFP_DMA,
102 get_order(session->bufsize));
103 if (!session->response) {
104 mutex_unlock(&session->mutex);
105 kfree(cmd);
106 return -ENOMEM;
107 }
108 debug_text_event(vmcp_debug, 1, cmd);
109 session->resp_size = cpcmd(cmd, session->response, session->bufsize,
110 &session->resp_code);
111 mutex_unlock(&session->mutex);
112 kfree(cmd);
113 *ppos = 0; /* reset the file pointer after a command */
114 return count;
115}
116
117
118/*
119 * These ioctls are available, as the semantics of the diagnose 8 call
120 * does not fit very well into a Linux call. Diagnose X'08' is described in
121 * CP Programming Services SC24-6084-00
122 *
123 * VMCP_GETCODE: gives the CP return code back to user space
124 * VMCP_SETBUF: sets the response buffer for the next write call. diagnose 8
125 * expects adjacent pages in real storage and to make matters worse, we
126 * dont know the size of the response. Therefore we default to PAGESIZE and
127 * let userspace to change the response size, if userspace expects a bigger
128 * response
129 */
130static long vmcp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
131{
132 struct vmcp_session *session;
133 int __user *argp;
134 int temp;
135
136 session = file->private_data;
137 if (is_compat_task())
138 argp = compat_ptr(arg);
139 else
140 argp = (int __user *)arg;
141 if (mutex_lock_interruptible(&session->mutex))
142 return -ERESTARTSYS;
143 switch (cmd) {
144 case VMCP_GETCODE:
145 temp = session->resp_code;
146 mutex_unlock(&session->mutex);
147 return put_user(temp, argp);
148 case VMCP_SETBUF:
149 free_pages((unsigned long)session->response,
150 get_order(session->bufsize));
151 session->response=NULL;
152 temp = get_user(session->bufsize, argp);
153 if (get_order(session->bufsize) > 8) {
154 session->bufsize = PAGE_SIZE;
155 temp = -EINVAL;
156 }
157 mutex_unlock(&session->mutex);
158 return temp;
159 case VMCP_GETSIZE:
160 temp = session->resp_size;
161 mutex_unlock(&session->mutex);
162 return put_user(temp, argp);
163 default:
164 mutex_unlock(&session->mutex);
165 return -ENOIOCTLCMD;
166 }
167}
168
169static const struct file_operations vmcp_fops = {
170 .owner = THIS_MODULE,
171 .open = vmcp_open,
172 .release = vmcp_release,
173 .read = vmcp_read,
174 .write = vmcp_write,
175 .unlocked_ioctl = vmcp_ioctl,
176 .compat_ioctl = vmcp_ioctl,
177 .llseek = no_llseek,
178};
179
180static struct miscdevice vmcp_dev = {
181 .name = "vmcp",
182 .minor = MISC_DYNAMIC_MINOR,
183 .fops = &vmcp_fops,
184};
185
186static int __init vmcp_init(void)
187{
188 int ret;
189
190 if (!MACHINE_IS_VM)
191 return 0;
192
193 vmcp_debug = debug_register("vmcp", 1, 1, 240);
194 if (!vmcp_debug)
195 return -ENOMEM;
196
197 ret = debug_register_view(vmcp_debug, &debug_hex_ascii_view);
198 if (ret) {
199 debug_unregister(vmcp_debug);
200 return ret;
201 }
202
203 ret = misc_register(&vmcp_dev);
204 if (ret)
205 debug_unregister(vmcp_debug);
206 return ret;
207}
208device_initcall(vmcp_init);