blob: 9fa92e45e0ee6fd123464047a03d3882a32a5ef0 [file] [log] [blame]
Greg Kroah-Hartman6f05e692017-11-14 18:38:03 +01001// SPDX-License-Identifier: GPL-2.0
Linus Torvalds1da177e2005-04-16 15:20:36 -07002/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 * Character device driver for reading z/VM *MONITOR service records.
4 *
Gerald Schaefer2b1e3e52009-06-16 10:30:50 +02005 * Copyright IBM Corp. 2004, 2009
6 *
7 * Author: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Linus Torvalds1da177e2005-04-16 15:20:36 -07008 */
9
Gerald Schaefera4f5a292008-12-25 13:39:42 +010010#define KMSG_COMPONENT "monreader"
11#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
12
Linus Torvalds1da177e2005-04-16 15:20:36 -070013#include <linux/module.h>
14#include <linux/moduleparam.h>
15#include <linux/init.h>
16#include <linux/errno.h>
17#include <linux/types.h>
18#include <linux/kernel.h>
19#include <linux/miscdevice.h>
20#include <linux/ctype.h>
21#include <linux/spinlock.h>
22#include <linux/interrupt.h>
Gerald Schaefer2ca5b6e2008-07-14 09:59:35 +020023#include <linux/poll.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090024#include <linux/slab.h>
Gerald Schaefer2ca5b6e2008-07-14 09:59:35 +020025#include <net/iucv/iucv.h>
Linus Torvalds7c0f6ba2016-12-24 11:46:01 -080026#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027#include <asm/ebcdic.h>
28#include <asm/extmem.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070029
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
31#define MON_COLLECT_SAMPLE 0x80
32#define MON_COLLECT_EVENT 0x40
33#define MON_SERVICE "*MONITOR"
34#define MON_IN_USE 0x01
35#define MON_MSGLIM 255
36
37static char mon_dcss_name[9] = "MONDCSS\0";
38
39struct mon_msg {
40 u32 pos;
41 u32 mca_offset;
Martin Schwidefskyc667aac2007-02-08 13:38:11 -080042 struct iucv_message msg;
Linus Torvalds1da177e2005-04-16 15:20:36 -070043 char msglim_reached;
44 char replied_msglim;
45};
46
47struct mon_private {
Martin Schwidefskyc667aac2007-02-08 13:38:11 -080048 struct iucv_path *path;
Linus Torvalds1da177e2005-04-16 15:20:36 -070049 struct mon_msg *msg_array[MON_MSGLIM];
50 unsigned int write_index;
51 unsigned int read_index;
52 atomic_t msglim_count;
53 atomic_t read_ready;
54 atomic_t iucv_connected;
55 atomic_t iucv_severed;
56};
57
58static unsigned long mon_in_use = 0;
59
60static unsigned long mon_dcss_start;
61static unsigned long mon_dcss_end;
62
63static DECLARE_WAIT_QUEUE_HEAD(mon_read_wait_queue);
64static DECLARE_WAIT_QUEUE_HEAD(mon_conn_wait_queue);
65
Linus Torvalds1da177e2005-04-16 15:20:36 -070066static u8 user_data_connect[16] = {
67 /* Version code, must be 0x01 for shared mode */
68 0x01,
69 /* what to collect */
70 MON_COLLECT_SAMPLE | MON_COLLECT_EVENT,
71 /* DCSS name in EBCDIC, 8 bytes padded with blanks */
72 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
73 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
74};
75
76static u8 user_data_sever[16] = {
77 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
78 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
79};
80
Linus Torvalds1da177e2005-04-16 15:20:36 -070081/******************************************************************************
82 * helper functions *
83 *****************************************************************************/
84/*
85 * Create the 8 bytes EBCDIC DCSS segment name from
86 * an ASCII name, incl. padding
87 */
Martin Schwidefsky9b0c4552007-05-10 15:45:44 +020088static void dcss_mkname(char *ascii_name, char *ebcdic_name)
Linus Torvalds1da177e2005-04-16 15:20:36 -070089{
90 int i;
91
92 for (i = 0; i < 8; i++) {
93 if (ascii_name[i] == '\0')
94 break;
95 ebcdic_name[i] = toupper(ascii_name[i]);
Peter Senna Tschudin3b974872015-08-04 17:11:15 +020096 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 for (; i < 8; i++)
98 ebcdic_name[i] = ' ';
99 ASCEBC(ebcdic_name, 8);
100}
101
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800102static inline unsigned long mon_mca_start(struct mon_msg *monmsg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103{
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800104 return *(u32 *) &monmsg->msg.rmmsg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105}
106
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800107static inline unsigned long mon_mca_end(struct mon_msg *monmsg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108{
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800109 return *(u32 *) &monmsg->msg.rmmsg[4];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110}
111
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800112static inline u8 mon_mca_type(struct mon_msg *monmsg, u8 index)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113{
114 return *((u8 *) mon_mca_start(monmsg) + monmsg->mca_offset + index);
115}
116
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800117static inline u32 mon_mca_size(struct mon_msg *monmsg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118{
119 return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1;
120}
121
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800122static inline u32 mon_rec_start(struct mon_msg *monmsg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123{
124 return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 4));
125}
126
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800127static inline u32 mon_rec_end(struct mon_msg *monmsg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128{
129 return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 8));
130}
131
Martin Schwidefsky9b0c4552007-05-10 15:45:44 +0200132static int mon_check_mca(struct mon_msg *monmsg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133{
134 if ((mon_rec_end(monmsg) <= mon_rec_start(monmsg)) ||
135 (mon_rec_start(monmsg) < mon_dcss_start) ||
136 (mon_rec_end(monmsg) > mon_dcss_end) ||
137 (mon_mca_type(monmsg, 0) == 0) ||
138 (mon_mca_size(monmsg) % 12 != 0) ||
139 (mon_mca_end(monmsg) <= mon_mca_start(monmsg)) ||
140 (mon_mca_end(monmsg) > mon_dcss_end) ||
141 (mon_mca_start(monmsg) < mon_dcss_start) ||
142 ((mon_mca_type(monmsg, 1) == 0) && (mon_mca_type(monmsg, 2) == 0)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 return 0;
145}
146
Martin Schwidefsky9b0c4552007-05-10 15:45:44 +0200147static int mon_send_reply(struct mon_msg *monmsg,
148 struct mon_private *monpriv)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 int rc;
151
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800152 rc = iucv_message_reply(monpriv->path, &monmsg->msg,
153 IUCV_IPRMDATA, NULL, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 atomic_dec(&monpriv->msglim_count);
155 if (likely(!monmsg->msglim_reached)) {
156 monmsg->pos = 0;
157 monmsg->mca_offset = 0;
158 monpriv->read_index = (monpriv->read_index + 1) %
159 MON_MSGLIM;
160 atomic_dec(&monpriv->read_ready);
161 } else
162 monmsg->replied_msglim = 1;
163 if (rc) {
Gerald Schaefera4f5a292008-12-25 13:39:42 +0100164 pr_err("Reading monitor data failed with rc=%i\n", rc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 return -EIO;
166 }
167 return 0;
168}
169
Martin Schwidefsky9b0c4552007-05-10 15:45:44 +0200170static void mon_free_mem(struct mon_private *monpriv)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171{
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800172 int i;
173
174 for (i = 0; i < MON_MSGLIM; i++)
Syam Sidhardhana75a2822013-03-07 01:33:55 +0530175 kfree(monpriv->msg_array[i]);
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800176 kfree(monpriv);
177}
178
Martin Schwidefsky9b0c4552007-05-10 15:45:44 +0200179static struct mon_private *mon_alloc_mem(void)
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800180{
181 int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 struct mon_private *monpriv;
183
Eric Sesterhenn88abaab2006-03-24 03:15:31 -0800184 monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
Gerald Schaefer2ca5b6e2008-07-14 09:59:35 +0200185 if (!monpriv)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 for (i = 0; i < MON_MSGLIM; i++) {
Eric Sesterhenn88abaab2006-03-24 03:15:31 -0800188 monpriv->msg_array[i] = kzalloc(sizeof(struct mon_msg),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 GFP_KERNEL);
190 if (!monpriv->msg_array[i]) {
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800191 mon_free_mem(monpriv);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192 return NULL;
193 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 }
195 return monpriv;
196}
197
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800198static inline void mon_next_mca(struct mon_msg *monmsg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199{
200 if (likely((mon_mca_size(monmsg) - monmsg->mca_offset) == 12))
201 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 monmsg->mca_offset += 12;
203 monmsg->pos = 0;
204}
205
Martin Schwidefsky9b0c4552007-05-10 15:45:44 +0200206static struct mon_msg *mon_next_message(struct mon_private *monpriv)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207{
208 struct mon_msg *monmsg;
209
210 if (!atomic_read(&monpriv->read_ready))
211 return NULL;
212 monmsg = monpriv->msg_array[monpriv->read_index];
213 if (unlikely(monmsg->replied_msglim)) {
214 monmsg->replied_msglim = 0;
215 monmsg->msglim_reached = 0;
216 monmsg->pos = 0;
217 monmsg->mca_offset = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 monpriv->read_index = (monpriv->read_index + 1) %
219 MON_MSGLIM;
220 atomic_dec(&monpriv->read_ready);
221 return ERR_PTR(-EOVERFLOW);
222 }
223 return monmsg;
224}
225
226
227/******************************************************************************
228 * IUCV handler *
229 *****************************************************************************/
Ursula Braun91e60eb2015-09-18 16:06:52 +0200230static void mon_iucv_path_complete(struct iucv_path *path, u8 *ipuser)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231{
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800232 struct mon_private *monpriv = path->private;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 atomic_set(&monpriv->iucv_connected, 1);
235 wake_up(&mon_conn_wait_queue);
236}
237
Ursula Braun91e60eb2015-09-18 16:06:52 +0200238static void mon_iucv_path_severed(struct iucv_path *path, u8 *ipuser)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239{
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800240 struct mon_private *monpriv = path->private;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241
Gerald Schaefera4f5a292008-12-25 13:39:42 +0100242 pr_err("z/VM *MONITOR system service disconnected with rc=%i\n",
243 ipuser[0]);
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800244 iucv_path_sever(path, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 atomic_set(&monpriv->iucv_severed, 1);
246 wake_up(&mon_conn_wait_queue);
247 wake_up_interruptible(&mon_read_wait_queue);
248}
249
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800250static void mon_iucv_message_pending(struct iucv_path *path,
251 struct iucv_message *msg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252{
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800253 struct mon_private *monpriv = path->private;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800255 memcpy(&monpriv->msg_array[monpriv->write_index]->msg,
256 msg, sizeof(*msg));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 if (atomic_inc_return(&monpriv->msglim_count) == MON_MSGLIM) {
Joe Perchesbaebc702016-03-03 20:49:57 -0800258 pr_warn("The read queue for monitor data is full\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 monpriv->msg_array[monpriv->write_index]->msglim_reached = 1;
260 }
261 monpriv->write_index = (monpriv->write_index + 1) % MON_MSGLIM;
262 atomic_inc(&monpriv->read_ready);
263 wake_up_interruptible(&mon_read_wait_queue);
264}
265
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800266static struct iucv_handler monreader_iucv_handler = {
267 .path_complete = mon_iucv_path_complete,
268 .path_severed = mon_iucv_path_severed,
269 .message_pending = mon_iucv_message_pending,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270};
271
272/******************************************************************************
273 * file operations *
274 *****************************************************************************/
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800275static int mon_open(struct inode *inode, struct file *filp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 struct mon_private *monpriv;
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800278 int rc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279
280 /*
281 * only one user allowed
282 */
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800283 rc = -EBUSY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284 if (test_and_set_bit(MON_IN_USE, &mon_in_use))
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800285 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800287 rc = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288 monpriv = mon_alloc_mem();
289 if (!monpriv)
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800290 goto out_use;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291
292 /*
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800293 * Connect to *MONITOR service
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 */
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800295 monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
296 if (!monpriv->path)
297 goto out_priv;
298 rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
299 MON_SERVICE, NULL, user_data_connect, monpriv);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300 if (rc) {
Gerald Schaefera4f5a292008-12-25 13:39:42 +0100301 pr_err("Connecting to the z/VM *MONITOR system service "
302 "failed with rc=%i\n", rc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303 rc = -EIO;
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800304 goto out_path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305 }
306 /*
307 * Wait for connection confirmation
308 */
309 wait_event(mon_conn_wait_queue,
310 atomic_read(&monpriv->iucv_connected) ||
311 atomic_read(&monpriv->iucv_severed));
312 if (atomic_read(&monpriv->iucv_severed)) {
313 atomic_set(&monpriv->iucv_severed, 0);
314 atomic_set(&monpriv->iucv_connected, 0);
315 rc = -EIO;
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800316 goto out_path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 filp->private_data = monpriv;
319 return nonseekable_open(inode, filp);
320
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800321out_path:
Gerald Schaefer2b1e3e52009-06-16 10:30:50 +0200322 iucv_path_free(monpriv->path);
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800323out_priv:
324 mon_free_mem(monpriv);
325out_use:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 clear_bit(MON_IN_USE, &mon_in_use);
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800327out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328 return rc;
329}
330
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800331static int mon_close(struct inode *inode, struct file *filp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332{
333 int rc, i;
334 struct mon_private *monpriv = filp->private_data;
335
336 /*
337 * Close IUCV connection and unregister
338 */
Gerald Schaefer2b1e3e52009-06-16 10:30:50 +0200339 if (monpriv->path) {
340 rc = iucv_path_sever(monpriv->path, user_data_sever);
341 if (rc)
Joe Perchesbaebc702016-03-03 20:49:57 -0800342 pr_warn("Disconnecting the z/VM *MONITOR system service failed with rc=%i\n",
343 rc);
Gerald Schaefer2b1e3e52009-06-16 10:30:50 +0200344 iucv_path_free(monpriv->path);
345 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 atomic_set(&monpriv->iucv_severed, 0);
348 atomic_set(&monpriv->iucv_connected, 0);
349 atomic_set(&monpriv->read_ready, 0);
350 atomic_set(&monpriv->msglim_count, 0);
351 monpriv->write_index = 0;
352 monpriv->read_index = 0;
353
354 for (i = 0; i < MON_MSGLIM; i++)
355 kfree(monpriv->msg_array[i]);
356 kfree(monpriv);
357 clear_bit(MON_IN_USE, &mon_in_use);
358 return 0;
359}
360
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800361static ssize_t mon_read(struct file *filp, char __user *data,
362 size_t count, loff_t *ppos)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363{
364 struct mon_private *monpriv = filp->private_data;
365 struct mon_msg *monmsg;
366 int ret;
367 u32 mce_start;
368
369 monmsg = mon_next_message(monpriv);
370 if (IS_ERR(monmsg))
371 return PTR_ERR(monmsg);
372
373 if (!monmsg) {
374 if (filp->f_flags & O_NONBLOCK)
375 return -EAGAIN;
376 ret = wait_event_interruptible(mon_read_wait_queue,
377 atomic_read(&monpriv->read_ready) ||
378 atomic_read(&monpriv->iucv_severed));
379 if (ret)
380 return ret;
381 if (unlikely(atomic_read(&monpriv->iucv_severed)))
382 return -EIO;
383 monmsg = monpriv->msg_array[monpriv->read_index];
384 }
385
Gerald Schaefer2ca5b6e2008-07-14 09:59:35 +0200386 if (!monmsg->pos)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387 monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 if (mon_check_mca(monmsg))
389 goto reply;
390
391 /* read monitor control element (12 bytes) first */
392 mce_start = mon_mca_start(monmsg) + monmsg->mca_offset;
393 if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) {
394 count = min(count, (size_t) mce_start + 12 - monmsg->pos);
395 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
396 count);
397 if (ret)
398 return -EFAULT;
399 monmsg->pos += count;
400 if (monmsg->pos == mce_start + 12)
401 monmsg->pos = mon_rec_start(monmsg);
402 goto out_copy;
403 }
404
405 /* read records */
406 if (monmsg->pos <= mon_rec_end(monmsg)) {
407 count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos
408 + 1);
409 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
410 count);
411 if (ret)
412 return -EFAULT;
413 monmsg->pos += count;
414 if (monmsg->pos > mon_rec_end(monmsg))
415 mon_next_mca(monmsg);
416 goto out_copy;
417 }
418reply:
419 ret = mon_send_reply(monmsg, monpriv);
420 return ret;
421
422out_copy:
423 *ppos += count;
424 return count;
425}
426
Al Viroafc9a422017-07-03 06:39:46 -0400427static __poll_t mon_poll(struct file *filp, struct poll_table_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428{
429 struct mon_private *monpriv = filp->private_data;
430
431 poll_wait(filp, &mon_read_wait_queue, p);
432 if (unlikely(atomic_read(&monpriv->iucv_severed)))
Linus Torvaldsa9a08842018-02-11 14:34:03 -0800433 return EPOLLERR;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434 if (atomic_read(&monpriv->read_ready))
Linus Torvaldsa9a08842018-02-11 14:34:03 -0800435 return EPOLLIN | EPOLLRDNORM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436 return 0;
437}
438
Arjan van de Vend54b1fd2007-02-12 00:55:34 -0800439static const struct file_operations mon_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440 .owner = THIS_MODULE,
441 .open = &mon_open,
442 .release = &mon_close,
443 .read = &mon_read,
444 .poll = &mon_poll,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200445 .llseek = noop_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446};
447
448static struct miscdevice mon_dev = {
449 .name = "monreader",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 .fops = &mon_fops,
451 .minor = MISC_DYNAMIC_MINOR,
452};
453
454/******************************************************************************
455 * module init/exit *
456 *****************************************************************************/
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800457static int __init mon_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458{
459 int rc;
460
461 if (!MACHINE_IS_VM) {
Gerald Schaefera4f5a292008-12-25 13:39:42 +0100462 pr_err("The z/VM *MONITOR record device driver cannot be "
463 "loaded without z/VM\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 return -ENODEV;
465 }
466
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800467 /*
468 * Register with IUCV and connect to *MONITOR service
469 */
470 rc = iucv_register(&monreader_iucv_handler, 1);
471 if (rc) {
Gerald Schaefera4f5a292008-12-25 13:39:42 +0100472 pr_err("The z/VM *MONITOR record device driver failed to "
473 "register with IUCV\n");
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800474 return rc;
475 }
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800476
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477 rc = segment_type(mon_dcss_name);
478 if (rc < 0) {
Martin Schwidefskyca683052008-04-17 07:46:31 +0200479 segment_warning(rc, mon_dcss_name);
Peter Oberparleiter8e1eaf42021-06-09 16:59:29 +0200480 goto out_iucv;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 }
482 if (rc != SEG_TYPE_SC) {
Gerald Schaefera4f5a292008-12-25 13:39:42 +0100483 pr_err("The specified *MONITOR DCSS %s does not have the "
484 "required type SC\n", mon_dcss_name);
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800485 rc = -EINVAL;
Peter Oberparleiter8e1eaf42021-06-09 16:59:29 +0200486 goto out_iucv;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487 }
488
489 rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
490 &mon_dcss_start, &mon_dcss_end);
491 if (rc < 0) {
Martin Schwidefskyca683052008-04-17 07:46:31 +0200492 segment_warning(rc, mon_dcss_name);
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800493 rc = -EINVAL;
Peter Oberparleiter8e1eaf42021-06-09 16:59:29 +0200494 goto out_iucv;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495 }
496 dcss_mkname(mon_dcss_name, &user_data_connect[8]);
497
Gerald Schaefer19634032009-12-07 12:52:17 +0100498 /*
499 * misc_register() has to be the last action in module_init(), because
500 * file operations will be available right after this.
501 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502 rc = misc_register(&mon_dev);
Gerald Schaefer2ca5b6e2008-07-14 09:59:35 +0200503 if (rc < 0 )
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505 return 0;
506
507out:
508 segment_unload(mon_dcss_name);
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800509out_iucv:
510 iucv_unregister(&monreader_iucv_handler, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 return rc;
512}
513
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800514static void __exit mon_exit(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515{
516 segment_unload(mon_dcss_name);
Akinobu Mita547415d52010-08-09 17:20:35 -0700517 misc_deregister(&mon_dev);
Martin Schwidefskyc667aac2007-02-08 13:38:11 -0800518 iucv_unregister(&monreader_iucv_handler, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519 return;
520}
521
522
523module_init(mon_init);
524module_exit(mon_exit);
525
526module_param_string(mondcss, mon_dcss_name, 9, 0444);
527MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR "
528 "service, max. 8 chars. Default is MONDCSS");
529
530MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>");
531MODULE_DESCRIPTION("Character device driver for reading z/VM "
532 "monitor service records.");
533MODULE_LICENSE("GPL");