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
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>
24 MODULE_LICENSE("GPL");
25 MODULE_AUTHOR("Christian Borntraeger <borntraeger@de.ibm.com>");
26 MODULE_DESCRIPTION("z/VM CP interface");
28 #define PRINTK_HEADER "vmcp: "
30 static debug_info_t
*vmcp_debug
;
32 static int vmcp_open(struct inode
*inode
, struct file
*file
)
34 struct vmcp_session
*session
;
36 if (!capable(CAP_SYS_ADMIN
))
39 session
= kmalloc(sizeof(*session
), GFP_KERNEL
);
42 session
->bufsize
= PAGE_SIZE
;
43 session
->response
= NULL
;
44 session
->resp_size
= 0;
45 mutex_init(&session
->mutex
);
46 file
->private_data
= session
;
47 return nonseekable_open(inode
, file
);
50 static int vmcp_release(struct inode
*inode
, struct file
*file
)
52 struct vmcp_session
*session
;
54 session
= (struct vmcp_session
*)file
->private_data
;
55 file
->private_data
= NULL
;
56 free_pages((unsigned long)session
->response
, get_order(session
->bufsize
));
62 vmcp_read(struct file
*file
, char __user
*buff
, size_t count
, loff_t
*ppos
)
66 struct vmcp_session
*session
;
68 session
= file
->private_data
;
69 if (mutex_lock_interruptible(&session
->mutex
))
71 if (!session
->response
) {
72 mutex_unlock(&session
->mutex
);
75 size
= min_t(size_t, session
->resp_size
, session
->bufsize
);
76 ret
= simple_read_from_buffer(buff
, count
, ppos
,
77 session
->response
, size
);
79 mutex_unlock(&session
->mutex
);
85 vmcp_write(struct file
*file
, const char __user
*buff
, size_t count
,
89 struct vmcp_session
*session
;
93 cmd
= kmalloc(count
+ 1, GFP_KERNEL
);
96 if (copy_from_user(cmd
, buff
, count
)) {
101 session
= (struct vmcp_session
*)file
->private_data
;
102 if (mutex_lock_interruptible(&session
->mutex
)) {
106 if (!session
->response
)
107 session
->response
= (char *)__get_free_pages(GFP_KERNEL
108 | __GFP_REPEAT
| GFP_DMA
,
109 get_order(session
->bufsize
));
110 if (!session
->response
) {
111 mutex_unlock(&session
->mutex
);
115 debug_text_event(vmcp_debug
, 1, cmd
);
116 session
->resp_size
= cpcmd(cmd
, session
->response
, session
->bufsize
,
117 &session
->resp_code
);
118 mutex_unlock(&session
->mutex
);
120 *ppos
= 0; /* reset the file pointer after a command */
126 * These ioctls are available, as the semantics of the diagnose 8 call
127 * does not fit very well into a Linux call. Diagnose X'08' is described in
128 * CP Programming Services SC24-6084-00
130 * VMCP_GETCODE: gives the CP return code back to user space
131 * VMCP_SETBUF: sets the response buffer for the next write call. diagnose 8
132 * expects adjacent pages in real storage and to make matters worse, we
133 * dont know the size of the response. Therefore we default to PAGESIZE and
134 * let userspace to change the response size, if userspace expects a bigger
137 static long vmcp_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
139 struct vmcp_session
*session
;
142 session
= (struct vmcp_session
*)file
->private_data
;
143 if (mutex_lock_interruptible(&session
->mutex
))
147 temp
= session
->resp_code
;
148 mutex_unlock(&session
->mutex
);
149 return put_user(temp
, (int __user
*)arg
);
151 free_pages((unsigned long)session
->response
,
152 get_order(session
->bufsize
));
153 session
->response
=NULL
;
154 temp
= get_user(session
->bufsize
, (int __user
*)arg
);
155 if (get_order(session
->bufsize
) > 8) {
156 session
->bufsize
= PAGE_SIZE
;
159 mutex_unlock(&session
->mutex
);
162 temp
= session
->resp_size
;
163 mutex_unlock(&session
->mutex
);
164 return put_user(temp
, (int __user
*)arg
);
166 mutex_unlock(&session
->mutex
);
171 static const struct file_operations vmcp_fops
= {
172 .owner
= THIS_MODULE
,
174 .release
= vmcp_release
,
177 .unlocked_ioctl
= vmcp_ioctl
,
178 .compat_ioctl
= vmcp_ioctl
,
181 static struct miscdevice vmcp_dev
= {
183 .minor
= MISC_DYNAMIC_MINOR
,
187 static int __init
vmcp_init(void)
191 if (!MACHINE_IS_VM
) {
192 PRINT_WARN("z/VM CP interface is only available under z/VM\n");
196 vmcp_debug
= debug_register("vmcp", 1, 1, 240);
200 ret
= debug_register_view(vmcp_debug
, &debug_hex_ascii_view
);
202 debug_unregister(vmcp_debug
);
206 ret
= misc_register(&vmcp_dev
);
208 debug_unregister(vmcp_debug
);
215 static void __exit
vmcp_exit(void)
217 misc_deregister(&vmcp_dev
);
218 debug_unregister(vmcp_debug
);
221 module_init(vmcp_init
);
222 module_exit(vmcp_exit
);