2 * Copyright IBM Corp. 2004,2007
3 * Interface implementation for communication with the z/VM control program
4 * Author(s): Christian Borntraeger <borntraeger@de.ibm.com>
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.
11 * The idea of this driver is based on cpint from Neale Ferguson and #CP in CMS
14 #define KMSG_COMPONENT "vmcp"
15 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
18 #include <linux/init.h>
19 #include <linux/kernel.h>
20 #include <linux/miscdevice.h>
21 #include <linux/module.h>
22 #include <linux/slab.h>
23 #include <asm/compat.h>
24 #include <asm/cpcmd.h>
25 #include <asm/debug.h>
26 #include <asm/uaccess.h>
29 MODULE_LICENSE("GPL");
30 MODULE_AUTHOR("Christian Borntraeger <borntraeger@de.ibm.com>");
31 MODULE_DESCRIPTION("z/VM CP interface");
33 static debug_info_t
*vmcp_debug
;
35 static int vmcp_open(struct inode
*inode
, struct file
*file
)
37 struct vmcp_session
*session
;
39 if (!capable(CAP_SYS_ADMIN
))
42 session
= kmalloc(sizeof(*session
), GFP_KERNEL
);
46 session
->bufsize
= PAGE_SIZE
;
47 session
->response
= NULL
;
48 session
->resp_size
= 0;
49 mutex_init(&session
->mutex
);
50 file
->private_data
= session
;
51 return nonseekable_open(inode
, file
);
54 static int vmcp_release(struct inode
*inode
, struct file
*file
)
56 struct vmcp_session
*session
;
58 session
= (struct vmcp_session
*)file
->private_data
;
59 file
->private_data
= NULL
;
60 free_pages((unsigned long)session
->response
, get_order(session
->bufsize
));
66 vmcp_read(struct file
*file
, char __user
*buff
, size_t count
, loff_t
*ppos
)
70 struct vmcp_session
*session
;
72 session
= file
->private_data
;
73 if (mutex_lock_interruptible(&session
->mutex
))
75 if (!session
->response
) {
76 mutex_unlock(&session
->mutex
);
79 size
= min_t(size_t, session
->resp_size
, session
->bufsize
);
80 ret
= simple_read_from_buffer(buff
, count
, ppos
,
81 session
->response
, size
);
83 mutex_unlock(&session
->mutex
);
89 vmcp_write(struct file
*file
, const char __user
*buff
, size_t count
,
93 struct vmcp_session
*session
;
97 cmd
= kmalloc(count
+ 1, GFP_KERNEL
);
100 if (copy_from_user(cmd
, buff
, count
)) {
105 session
= (struct vmcp_session
*)file
->private_data
;
106 if (mutex_lock_interruptible(&session
->mutex
)) {
110 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 mutex_unlock(&session
->mutex
);
119 debug_text_event(vmcp_debug
, 1, cmd
);
120 session
->resp_size
= cpcmd(cmd
, session
->response
, session
->bufsize
,
121 &session
->resp_code
);
122 mutex_unlock(&session
->mutex
);
124 *ppos
= 0; /* reset the file pointer after a command */
130 * These ioctls are available, as the semantics of the diagnose 8 call
131 * does not fit very well into a Linux call. Diagnose X'08' is described in
132 * CP Programming Services SC24-6084-00
134 * VMCP_GETCODE: gives the CP return code back to user space
135 * VMCP_SETBUF: sets the response buffer for the next write call. diagnose 8
136 * expects adjacent pages in real storage and to make matters worse, we
137 * dont know the size of the response. Therefore we default to PAGESIZE and
138 * let userspace to change the response size, if userspace expects a bigger
141 static long vmcp_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
143 struct vmcp_session
*session
;
147 session
= (struct vmcp_session
*)file
->private_data
;
148 if (is_compat_task())
149 argp
= compat_ptr(arg
);
151 argp
= (int __user
*)arg
;
152 if (mutex_lock_interruptible(&session
->mutex
))
156 temp
= session
->resp_code
;
157 mutex_unlock(&session
->mutex
);
158 return put_user(temp
, argp
);
160 free_pages((unsigned long)session
->response
,
161 get_order(session
->bufsize
));
162 session
->response
=NULL
;
163 temp
= get_user(session
->bufsize
, argp
);
164 if (get_order(session
->bufsize
) > 8) {
165 session
->bufsize
= PAGE_SIZE
;
168 mutex_unlock(&session
->mutex
);
171 temp
= session
->resp_size
;
172 mutex_unlock(&session
->mutex
);
173 return put_user(temp
, argp
);
175 mutex_unlock(&session
->mutex
);
180 static const struct file_operations vmcp_fops
= {
181 .owner
= THIS_MODULE
,
183 .release
= vmcp_release
,
186 .unlocked_ioctl
= vmcp_ioctl
,
187 .compat_ioctl
= vmcp_ioctl
,
190 static struct miscdevice vmcp_dev
= {
192 .minor
= MISC_DYNAMIC_MINOR
,
196 static int __init
vmcp_init(void)
200 if (!MACHINE_IS_VM
) {
201 pr_warning("The z/VM CP interface device driver cannot be "
202 "loaded without z/VM\n");
206 vmcp_debug
= debug_register("vmcp", 1, 1, 240);
210 ret
= debug_register_view(vmcp_debug
, &debug_hex_ascii_view
);
212 debug_unregister(vmcp_debug
);
216 ret
= misc_register(&vmcp_dev
);
218 debug_unregister(vmcp_debug
);
225 static void __exit
vmcp_exit(void)
227 misc_deregister(&vmcp_dev
);
228 debug_unregister(vmcp_debug
);
231 module_init(vmcp_init
);
232 module_exit(vmcp_exit
);