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);