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Christian Borntraeger6b979de2005-06-25 14:55:32 -07001/*
Heiko Carstensa53c8fa2012-07-20 11:15:04 +02002 * Copyright IBM Corp. 2004, 2010
Christian Borntraeger45af3af2006-09-20 15:59:24 +02003 * Interface implementation for communication with the z/VM control program
Christian Borntraeger6b979de2005-06-25 14:55:32 -07004 *
Heiko Carstensf73a2b02010-05-17 10:00:06 +02005 * Author(s): Christian Borntraeger <borntraeger@de.ibm.com>
Christian Borntraeger6b979de2005-06-25 14:55:32 -07006 *
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.
Heiko Carstensf73a2b02010-05-17 10:00:06 +020010 *
Christian Borntraeger6b979de2005-06-25 14:55:32 -070011 * 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>
Heiko Carstens048cd4e2012-02-27 10:01:52 +010016#include <linux/compat.h>
Christian Borntraeger6b979de2005-06-25 14:55:32 -070017#include <linux/kernel.h>
18#include <linux/miscdevice.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090019#include <linux/slab.h>
Heiko Carstens3a4c5d52011-07-30 09:25:15 +020020#include <linux/export.h>
Heiko Carstens8f3eabe2010-01-13 20:44:31 +010021#include <asm/compat.h>
Christian Borntraeger6b979de2005-06-25 14:55:32 -070022#include <asm/cpcmd.h>
23#include <asm/debug.h>
24#include <asm/uaccess.h>
25#include "vmcp.h"
26
Christian Borntraeger6b979de2005-06-25 14:55:32 -070027static 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;
Arnd Bergmann6c111d82008-05-20 19:16:59 +020039
Christian Borntraeger6b979de2005-06-25 14:55:32 -070040 session->bufsize = PAGE_SIZE;
41 session->response = NULL;
42 session->resp_size = 0;
Christian Borntraegerd9d119f2007-07-17 13:36:05 +020043 mutex_init(&session->mutex);
Christian Borntraeger6b979de2005-06-25 14:55:32 -070044 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
Joe Perches27e49942010-09-04 18:52:45 -070052 session = file->private_data;
Christian Borntraeger6b979de2005-06-25 14:55:32 -070053 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
Christian Borntraegerd9d119f2007-07-17 13:36:05 +020060vmcp_read(struct file *file, char __user *buff, size_t count, loff_t *ppos)
Christian Borntraeger6b979de2005-06-25 14:55:32 -070061{
Akinobu Mita77858572008-07-14 09:59:14 +020062 ssize_t ret;
63 size_t size;
Christian Borntraeger6b979de2005-06-25 14:55:32 -070064 struct vmcp_session *session;
65
Akinobu Mita77858572008-07-14 09:59:14 +020066 session = file->private_data;
Christian Borntraegerd9d119f2007-07-17 13:36:05 +020067 if (mutex_lock_interruptible(&session->mutex))
Christian Borntraeger6b979de2005-06-25 14:55:32 -070068 return -ERESTARTSYS;
69 if (!session->response) {
Christian Borntraegerd9d119f2007-07-17 13:36:05 +020070 mutex_unlock(&session->mutex);
Christian Borntraeger6b979de2005-06-25 14:55:32 -070071 return 0;
72 }
Akinobu Mita77858572008-07-14 09:59:14 +020073 size = min_t(size_t, session->resp_size, session->bufsize);
74 ret = simple_read_from_buffer(buff, count, ppos,
75 session->response, size);
Christian Borntraeger6b979de2005-06-25 14:55:32 -070076
Christian Borntraegerd9d119f2007-07-17 13:36:05 +020077 mutex_unlock(&session->mutex);
Akinobu Mita77858572008-07-14 09:59:14 +020078
79 return ret;
Christian Borntraeger6b979de2005-06-25 14:55:32 -070080}
81
82static ssize_t
Christian Borntraegerd9d119f2007-07-17 13:36:05 +020083vmcp_write(struct file *file, const char __user *buff, size_t count,
84 loff_t *ppos)
Christian Borntraeger6b979de2005-06-25 14:55:32 -070085{
86 char *cmd;
87 struct vmcp_session *session;
88
89 if (count > 240)
90 return -EINVAL;
91 cmd = kmalloc(count + 1, GFP_KERNEL);
92 if (!cmd)
93 return -ENOMEM;
94 if (copy_from_user(cmd, buff, count)) {
95 kfree(cmd);
96 return -EFAULT;
97 }
98 cmd[count] = '\0';
Joe Perches27e49942010-09-04 18:52:45 -070099 session = file->private_data;
Christian Borntraegerd9d119f2007-07-17 13:36:05 +0200100 if (mutex_lock_interruptible(&session->mutex)) {
Christian Borntraegera5da8662005-11-07 00:59:12 -0800101 kfree(cmd);
Christian Borntraeger6b979de2005-06-25 14:55:32 -0700102 return -ERESTARTSYS;
Christian Borntraegera5da8662005-11-07 00:59:12 -0800103 }
Christian Borntraeger6b979de2005-06-25 14:55:32 -0700104 if (!session->response)
105 session->response = (char *)__get_free_pages(GFP_KERNEL
Christian Borntraegerd9d119f2007-07-17 13:36:05 +0200106 | __GFP_REPEAT | GFP_DMA,
Christian Borntraeger6b979de2005-06-25 14:55:32 -0700107 get_order(session->bufsize));
108 if (!session->response) {
Christian Borntraegerd9d119f2007-07-17 13:36:05 +0200109 mutex_unlock(&session->mutex);
Christian Borntraeger6b979de2005-06-25 14:55:32 -0700110 kfree(cmd);
111 return -ENOMEM;
112 }
113 debug_text_event(vmcp_debug, 1, cmd);
Christian Borntraegerd9d119f2007-07-17 13:36:05 +0200114 session->resp_size = cpcmd(cmd, session->response, session->bufsize,
115 &session->resp_code);
116 mutex_unlock(&session->mutex);
Christian Borntraeger6b979de2005-06-25 14:55:32 -0700117 kfree(cmd);
118 *ppos = 0; /* reset the file pointer after a command */
119 return count;
120}
121
122
123/*
124 * These ioctls are available, as the semantics of the diagnose 8 call
125 * does not fit very well into a Linux call. Diagnose X'08' is described in
126 * CP Programming Services SC24-6084-00
127 *
128 * VMCP_GETCODE: gives the CP return code back to user space
129 * VMCP_SETBUF: sets the response buffer for the next write call. diagnose 8
130 * expects adjacent pages in real storage and to make matters worse, we
131 * dont know the size of the response. Therefore we default to PAGESIZE and
132 * let userspace to change the response size, if userspace expects a bigger
133 * response
134 */
135static long vmcp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
136{
137 struct vmcp_session *session;
Heiko Carstens8f3eabe2010-01-13 20:44:31 +0100138 int __user *argp;
Christian Borntraeger6b979de2005-06-25 14:55:32 -0700139 int temp;
140
Joe Perches27e49942010-09-04 18:52:45 -0700141 session = file->private_data;
Heiko Carstens8f3eabe2010-01-13 20:44:31 +0100142 if (is_compat_task())
143 argp = compat_ptr(arg);
144 else
145 argp = (int __user *)arg;
Christian Borntraegerd9d119f2007-07-17 13:36:05 +0200146 if (mutex_lock_interruptible(&session->mutex))
Christian Borntraeger6b979de2005-06-25 14:55:32 -0700147 return -ERESTARTSYS;
148 switch (cmd) {
149 case VMCP_GETCODE:
150 temp = session->resp_code;
Christian Borntraegerd9d119f2007-07-17 13:36:05 +0200151 mutex_unlock(&session->mutex);
Heiko Carstens8f3eabe2010-01-13 20:44:31 +0100152 return put_user(temp, argp);
Christian Borntraeger6b979de2005-06-25 14:55:32 -0700153 case VMCP_SETBUF:
154 free_pages((unsigned long)session->response,
155 get_order(session->bufsize));
156 session->response=NULL;
Heiko Carstens8f3eabe2010-01-13 20:44:31 +0100157 temp = get_user(session->bufsize, argp);
Christian Borntraeger6b979de2005-06-25 14:55:32 -0700158 if (get_order(session->bufsize) > 8) {
159 session->bufsize = PAGE_SIZE;
160 temp = -EINVAL;
161 }
Christian Borntraegerd9d119f2007-07-17 13:36:05 +0200162 mutex_unlock(&session->mutex);
Christian Borntraeger6b979de2005-06-25 14:55:32 -0700163 return temp;
164 case VMCP_GETSIZE:
165 temp = session->resp_size;
Christian Borntraegerd9d119f2007-07-17 13:36:05 +0200166 mutex_unlock(&session->mutex);
Heiko Carstens8f3eabe2010-01-13 20:44:31 +0100167 return put_user(temp, argp);
Christian Borntraeger6b979de2005-06-25 14:55:32 -0700168 default:
Christian Borntraegerd9d119f2007-07-17 13:36:05 +0200169 mutex_unlock(&session->mutex);
Christian Borntraeger6b979de2005-06-25 14:55:32 -0700170 return -ENOIOCTLCMD;
171 }
172}
173
Arjan van de Vend54b1fd2007-02-12 00:55:34 -0800174static const struct file_operations vmcp_fops = {
Christian Borntraeger6b979de2005-06-25 14:55:32 -0700175 .owner = THIS_MODULE,
Robert P. J. Dayd197e692007-07-10 11:24:07 +0200176 .open = vmcp_open,
177 .release = vmcp_release,
178 .read = vmcp_read,
179 .write = vmcp_write,
180 .unlocked_ioctl = vmcp_ioctl,
Christian Borntraegerd9d119f2007-07-17 13:36:05 +0200181 .compat_ioctl = vmcp_ioctl,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200182 .llseek = no_llseek,
Christian Borntraeger6b979de2005-06-25 14:55:32 -0700183};
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
Heiko Carstensf73a2b02010-05-17 10:00:06 +0200195 if (!MACHINE_IS_VM)
196 return 0;
Christian Borntraegera44008f2008-07-14 09:59:43 +0200197
Michael Holzheu66a464d2005-06-25 14:55:33 -0700198 vmcp_debug = debug_register("vmcp", 1, 1, 240);
Christian Borntraegera44008f2008-07-14 09:59:43 +0200199 if (!vmcp_debug)
Christian Borntraegerd9d119f2007-07-17 13:36:05 +0200200 return -ENOMEM;
Christian Borntraegera44008f2008-07-14 09:59:43 +0200201
Christian Borntraegerd9d119f2007-07-17 13:36:05 +0200202 ret = debug_register_view(vmcp_debug, &debug_hex_ascii_view);
203 if (ret) {
Christian Borntraegerd9d119f2007-07-17 13:36:05 +0200204 debug_unregister(vmcp_debug);
205 return ret;
206 }
Christian Borntraegera44008f2008-07-14 09:59:43 +0200207
Christian Borntraegerd9d119f2007-07-17 13:36:05 +0200208 ret = misc_register(&vmcp_dev);
Heiko Carstensf73a2b02010-05-17 10:00:06 +0200209 if (ret)
Christian Borntraegerd9d119f2007-07-17 13:36:05 +0200210 debug_unregister(vmcp_debug);
Heiko Carstensf73a2b02010-05-17 10:00:06 +0200211 return ret;
Christian Borntraeger6b979de2005-06-25 14:55:32 -0700212}
Heiko Carstensf73a2b02010-05-17 10:00:06 +0200213device_initcall(vmcp_init);