drivers/s390/char/monreader.c

   1 /*
   2  * drivers/s390/char/monreader.c
   3  *
   4  * Character device driver for reading z/VM *MONITOR service records.
   5  *
   6  * Copyright 2004 IBM Corporation, IBM Deutschland Entwicklung GmbH.
   7  *
   8  * Author: Gerald Schaefer <geraldsc@de.ibm.com>
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/moduleparam.h>
  13 #include <linux/init.h>
  14 #include <linux/errno.h>
  15 #include <linux/types.h>
  16 #include <linux/kernel.h>
  17 #include <linux/miscdevice.h>
  18 #include <linux/ctype.h>
  19 #include <linux/spinlock.h>
  20 #include <linux/interrupt.h>
  21 #include <asm/uaccess.h>
  22 #include <asm/ebcdic.h>
  23 #include <asm/extmem.h>
  24 #include <linux/poll.h>
  25 #include <net/iucv/iucv.h>
  26
  27
  28 //#define MON_DEBUG                     /* Debug messages on/off */
  29
  30 #define MON_NAME "monreader"
  31
  32 #define P_INFO(x...)    printk(KERN_INFO MON_NAME " info: " x)
  33 #define P_ERROR(x...)   printk(KERN_ERR MON_NAME " error: " x)
  34 #define P_WARNING(x...) printk(KERN_WARNING MON_NAME " warning: " x)
  35
  36 #ifdef MON_DEBUG
  37 #define P_DEBUG(x...)   printk(KERN_DEBUG MON_NAME " debug: " x)
  38 #else
  39 #define P_DEBUG(x...)   do {} while (0)
  40 #endif
  41
  42 #define MON_COLLECT_SAMPLE 0x80
  43 #define MON_COLLECT_EVENT  0x40
  44 #define MON_SERVICE        "*MONITOR"
  45 #define MON_IN_USE         0x01
  46 #define MON_MSGLIM         255
  47
  48 static char mon_dcss_name[9] = "MONDCSS\0";
  49
  50 struct mon_msg {
  51         u32 pos;
  52         u32 mca_offset;
  53         struct iucv_message msg;
  54         char msglim_reached;
  55         char replied_msglim;
  56 };
  57
  58 struct mon_private {
  59         struct iucv_path *path;
  60         struct mon_msg *msg_array[MON_MSGLIM];
  61         unsigned int   write_index;
  62         unsigned int   read_index;
  63         atomic_t msglim_count;
  64         atomic_t read_ready;
  65         atomic_t iucv_connected;
  66         atomic_t iucv_severed;
  67 };
  68
  69 static unsigned long mon_in_use = 0;
  70
  71 static unsigned long mon_dcss_start;
  72 static unsigned long mon_dcss_end;
  73
  74 static DECLARE_WAIT_QUEUE_HEAD(mon_read_wait_queue);
  75 static DECLARE_WAIT_QUEUE_HEAD(mon_conn_wait_queue);
  76
  77 static u8 user_data_connect[16] = {
  78         /* Version code, must be 0x01 for shared mode */
  79         0x01,
  80         /* what to collect */
  81         MON_COLLECT_SAMPLE | MON_COLLECT_EVENT,
  82         /* DCSS name in EBCDIC, 8 bytes padded with blanks */
  83         0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  84         0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  85 };
  86
  87 static u8 user_data_sever[16] = {
  88         0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  89         0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  90 };
  91
  92
  93 /******************************************************************************
  94  *                             helper functions                               *
  95  *****************************************************************************/
  96 /*
  97  * Create the 8 bytes EBCDIC DCSS segment name from
  98  * an ASCII name, incl. padding
  99  */
 100 static void dcss_mkname(char *ascii_name, char *ebcdic_name)
 101 {
 102         int i;
 103
 104         for (i = 0; i < 8; i++) {
 105                 if (ascii_name[i] == '\0')
 106                         break;
 107                 ebcdic_name[i] = toupper(ascii_name[i]);
 108         };
 109         for (; i < 8; i++)
 110                 ebcdic_name[i] = ' ';
 111         ASCEBC(ebcdic_name, 8);
 112 }
 113
 114 /*
 115  * print appropriate error message for segment_load()/segment_type()
 116  * return code
 117  */
 118 static void mon_segment_warn(int rc, char* seg_name)
 119 {
 120         switch (rc) {
 121         case -ENOENT:
 122                 P_WARNING("cannot load/query segment %s, does not exist\n",
 123                           seg_name);
 124                 break;
 125         case -ENOSYS:
 126                 P_WARNING("cannot load/query segment %s, not running on VM\n",
 127                           seg_name);
 128                 break;
 129         case -EIO:
 130                 P_WARNING("cannot load/query segment %s, hardware error\n",
 131                           seg_name);
 132                 break;
 133         case -ENOTSUPP:
 134                 P_WARNING("cannot load/query segment %s, is a multi-part "
 135                           "segment\n", seg_name);
 136                 break;
 137         case -ENOSPC:
 138                 P_WARNING("cannot load/query segment %s, overlaps with "
 139                           "storage\n", seg_name);
 140                 break;
 141         case -EBUSY:
 142                 P_WARNING("cannot load/query segment %s, overlaps with "
 143                           "already loaded dcss\n", seg_name);
 144                 break;
 145         case -EPERM:
 146                 P_WARNING("cannot load/query segment %s, already loaded in "
 147                           "incompatible mode\n", seg_name);
 148                 break;
 149         case -ENOMEM:
 150                 P_WARNING("cannot load/query segment %s, out of memory\n",
 151                           seg_name);
 152                 break;
 153         case -ERANGE:
 154                 P_WARNING("cannot load/query segment %s, exceeds kernel "
 155                           "mapping range\n", seg_name);
 156                 break;
 157         default:
 158                 P_WARNING("cannot load/query segment %s, return value %i\n",
 159                           seg_name, rc);
 160                 break;
 161         }
 162 }
 163
 164 static inline unsigned long mon_mca_start(struct mon_msg *monmsg)
 165 {
 166         return *(u32 *) &monmsg->msg.rmmsg;
 167 }
 168
 169 static inline unsigned long mon_mca_end(struct mon_msg *monmsg)
 170 {
 171         return *(u32 *) &monmsg->msg.rmmsg[4];
 172 }
 173
 174 static inline u8 mon_mca_type(struct mon_msg *monmsg, u8 index)
 175 {
 176         return *((u8 *) mon_mca_start(monmsg) + monmsg->mca_offset + index);
 177 }
 178
 179 static inline u32 mon_mca_size(struct mon_msg *monmsg)
 180 {
 181         return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1;
 182 }
 183
 184 static inline u32 mon_rec_start(struct mon_msg *monmsg)
 185 {
 186         return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 4));
 187 }
 188
 189 static inline u32 mon_rec_end(struct mon_msg *monmsg)
 190 {
 191         return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 8));
 192 }
 193
 194 static int mon_check_mca(struct mon_msg *monmsg)
 195 {
 196         if ((mon_rec_end(monmsg) <= mon_rec_start(monmsg)) ||
 197             (mon_rec_start(monmsg) < mon_dcss_start) ||
 198             (mon_rec_end(monmsg) > mon_dcss_end) ||
 199             (mon_mca_type(monmsg, 0) == 0) ||
 200             (mon_mca_size(monmsg) % 12 != 0) ||
 201             (mon_mca_end(monmsg) <= mon_mca_start(monmsg)) ||
 202             (mon_mca_end(monmsg) > mon_dcss_end) ||
 203             (mon_mca_start(monmsg) < mon_dcss_start) ||
 204             ((mon_mca_type(monmsg, 1) == 0) && (mon_mca_type(monmsg, 2) == 0)))
 205         {
 206                 P_DEBUG("READ, IGNORED INVALID MCA\n\n");
 207                 return -EINVAL;
 208         }
 209         return 0;
 210 }
 211
 212 static int mon_send_reply(struct mon_msg *monmsg,
 213                           struct mon_private *monpriv)
 214 {
 215         int rc;
 216
 217         P_DEBUG("read, REPLY: pathid = 0x%04X, msgid = 0x%08X, trgcls = "
 218                 "0x%08X\n\n",
 219                 monpriv->path->pathid, monmsg->msg.id, monmsg->msg.class);
 220
 221         rc = iucv_message_reply(monpriv->path, &monmsg->msg,
 222                                 IUCV_IPRMDATA, NULL, 0);
 223         atomic_dec(&monpriv->msglim_count);
 224         if (likely(!monmsg->msglim_reached)) {
 225                 monmsg->pos = 0;
 226                 monmsg->mca_offset = 0;
 227                 monpriv->read_index = (monpriv->read_index + 1) %
 228                                       MON_MSGLIM;
 229                 atomic_dec(&monpriv->read_ready);
 230         } else
 231                 monmsg->replied_msglim = 1;
 232         if (rc) {
 233                 P_ERROR("read, IUCV reply failed with rc = %i\n\n", rc);
 234                 return -EIO;
 235         }
 236         return 0;
 237 }
 238
 239 static void mon_free_mem(struct mon_private *monpriv)
 240 {
 241         int i;
 242
 243         for (i = 0; i < MON_MSGLIM; i++)
 244                 if (monpriv->msg_array[i])
 245                         kfree(monpriv->msg_array[i]);
 246         kfree(monpriv);
 247 }
 248
 249 static struct mon_private *mon_alloc_mem(void)
 250 {
 251         int i;
 252         struct mon_private *monpriv;
 253
 254         monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
 255         if (!monpriv) {
 256                 P_ERROR("no memory for monpriv\n");
 257                 return NULL;
 258         }
 259         for (i = 0; i < MON_MSGLIM; i++) {
 260                 monpriv->msg_array[i] = kzalloc(sizeof(struct mon_msg),
 261                                                     GFP_KERNEL);
 262                 if (!monpriv->msg_array[i]) {
 263                         P_ERROR("open, no memory for msg_array\n");
 264                         mon_free_mem(monpriv);
 265                         return NULL;
 266                 }
 267         }
 268         return monpriv;
 269 }
 270
 271 static inline void mon_read_debug(struct mon_msg *monmsg,
 272                                   struct mon_private *monpriv)
 273 {
 274 #ifdef MON_DEBUG
 275         u8 msg_type[2], mca_type;
 276         unsigned long records_len;
 277
 278         records_len = mon_rec_end(monmsg) - mon_rec_start(monmsg) + 1;
 279
 280         memcpy(msg_type, &monmsg->msg.class, 2);
 281         EBCASC(msg_type, 2);
 282         mca_type = mon_mca_type(monmsg, 0);
 283         EBCASC(&mca_type, 1);
 284
 285         P_DEBUG("read, mon_read_index = %i, mon_write_index = %i\n",
 286                 monpriv->read_index, monpriv->write_index);
 287         P_DEBUG("read, pathid = 0x%04X, msgid = 0x%08X, trgcls = 0x%08X\n",
 288                 monpriv->path->pathid, monmsg->msg.id, monmsg->msg.class);
 289         P_DEBUG("read, msg_type = '%c%c', mca_type = '%c' / 0x%X / 0x%X\n",
 290                 msg_type[0], msg_type[1], mca_type ? mca_type : 'X',
 291                 mon_mca_type(monmsg, 1), mon_mca_type(monmsg, 2));
 292         P_DEBUG("read, MCA: start = 0x%lX, end = 0x%lX\n",
 293                 mon_mca_start(monmsg), mon_mca_end(monmsg));
 294         P_DEBUG("read, REC: start = 0x%X, end = 0x%X, len = %lu\n\n",
 295                 mon_rec_start(monmsg), mon_rec_end(monmsg), records_len);
 296         if (mon_mca_size(monmsg) > 12)
 297                 P_DEBUG("READ, MORE THAN ONE MCA\n\n");
 298 #endif
 299 }
 300
 301 static inline void mon_next_mca(struct mon_msg *monmsg)
 302 {
 303         if (likely((mon_mca_size(monmsg) - monmsg->mca_offset) == 12))
 304                 return;
 305         P_DEBUG("READ, NEXT MCA\n\n");
 306         monmsg->mca_offset += 12;
 307         monmsg->pos = 0;
 308 }
 309
 310 static struct mon_msg *mon_next_message(struct mon_private *monpriv)
 311 {
 312         struct mon_msg *monmsg;
 313
 314         if (!atomic_read(&monpriv->read_ready))
 315                 return NULL;
 316         monmsg = monpriv->msg_array[monpriv->read_index];
 317         if (unlikely(monmsg->replied_msglim)) {
 318                 monmsg->replied_msglim = 0;
 319                 monmsg->msglim_reached = 0;
 320                 monmsg->pos = 0;
 321                 monmsg->mca_offset = 0;
 322                 P_WARNING("read, message limit reached\n");
 323                 monpriv->read_index = (monpriv->read_index + 1) %
 324                                       MON_MSGLIM;
 325                 atomic_dec(&monpriv->read_ready);
 326                 return ERR_PTR(-EOVERFLOW);
 327         }
 328         return monmsg;
 329 }
 330
 331
 332 /******************************************************************************
 333  *                               IUCV handler                                 *
 334  *****************************************************************************/
 335 static void mon_iucv_path_complete(struct iucv_path *path, u8 ipuser[16])
 336 {
 337         struct mon_private *monpriv = path->private;
 338
 339         P_DEBUG("IUCV connection completed\n");
 340         P_DEBUG("IUCV ACCEPT (from *MONITOR): Version = 0x%02X, Event = "
 341                 "0x%02X, Sample = 0x%02X\n",
 342                 ipuser[0], ipuser[1], ipuser[2]);
 343         atomic_set(&monpriv->iucv_connected, 1);
 344         wake_up(&mon_conn_wait_queue);
 345 }
 346
 347 static void mon_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
 348 {
 349         struct mon_private *monpriv = path->private;
 350
 351         P_ERROR("IUCV connection severed with rc = 0x%X\n", ipuser[0]);
 352         iucv_path_sever(path, NULL);
 353         atomic_set(&monpriv->iucv_severed, 1);
 354         wake_up(&mon_conn_wait_queue);
 355         wake_up_interruptible(&mon_read_wait_queue);
 356 }
 357
 358 static void mon_iucv_message_pending(struct iucv_path *path,
 359                                      struct iucv_message *msg)
 360 {
 361         struct mon_private *monpriv = path->private;
 362
 363         P_DEBUG("IUCV message pending\n");
 364         memcpy(&monpriv->msg_array[monpriv->write_index]->msg,
 365                msg, sizeof(*msg));
 366         if (atomic_inc_return(&monpriv->msglim_count) == MON_MSGLIM) {
 367                 P_WARNING("IUCV message pending, message limit (%i) reached\n",
 368                           MON_MSGLIM);
 369                 monpriv->msg_array[monpriv->write_index]->msglim_reached = 1;
 370         }
 371         monpriv->write_index = (monpriv->write_index + 1) % MON_MSGLIM;
 372         atomic_inc(&monpriv->read_ready);
 373         wake_up_interruptible(&mon_read_wait_queue);
 374 }
 375
 376 static struct iucv_handler monreader_iucv_handler = {
 377         .path_complete   = mon_iucv_path_complete,
 378         .path_severed    = mon_iucv_path_severed,
 379         .message_pending = mon_iucv_message_pending,
 380 };
 381
 382 /******************************************************************************
 383  *                               file operations                              *
 384  *****************************************************************************/
 385 static int mon_open(struct inode *inode, struct file *filp)
 386 {
 387         struct mon_private *monpriv;
 388         int rc;
 389
 390         /*
 391          * only one user allowed
 392          */
 393         rc = -EBUSY;
 394         if (test_and_set_bit(MON_IN_USE, &mon_in_use))
 395                 goto out;
 396
 397         rc = -ENOMEM;
 398         monpriv = mon_alloc_mem();
 399         if (!monpriv)
 400                 goto out_use;
 401
 402         /*
 403          * Connect to *MONITOR service
 404          */
 405         monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
 406         if (!monpriv->path)
 407                 goto out_priv;
 408         rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
 409                                MON_SERVICE, NULL, user_data_connect, monpriv);
 410         if (rc) {
 411                 P_ERROR("iucv connection to *MONITOR failed with "
 412                         "IPUSER SEVER code = %i\n", rc);
 413                 rc = -EIO;
 414                 goto out_path;
 415         }
 416         /*
 417          * Wait for connection confirmation
 418          */
 419         wait_event(mon_conn_wait_queue,
 420                    atomic_read(&monpriv->iucv_connected) ||
 421                    atomic_read(&monpriv->iucv_severed));
 422         if (atomic_read(&monpriv->iucv_severed)) {
 423                 atomic_set(&monpriv->iucv_severed, 0);
 424                 atomic_set(&monpriv->iucv_connected, 0);
 425                 rc = -EIO;
 426                 goto out_path;
 427         }
 428         P_INFO("open, established connection to *MONITOR service\n\n");
 429         filp->private_data = monpriv;
 430         return nonseekable_open(inode, filp);
 431
 432 out_path:
 433         kfree(monpriv->path);
 434 out_priv:
 435         mon_free_mem(monpriv);
 436 out_use:
 437         clear_bit(MON_IN_USE, &mon_in_use);
 438 out:
 439         return rc;
 440 }
 441
 442 static int mon_close(struct inode *inode, struct file *filp)
 443 {
 444         int rc, i;
 445         struct mon_private *monpriv = filp->private_data;
 446
 447         /*
 448          * Close IUCV connection and unregister
 449          */
 450         rc = iucv_path_sever(monpriv->path, user_data_sever);
 451         if (rc)
 452                 P_ERROR("close, iucv_sever failed with rc = %i\n", rc);
 453         else
 454                 P_INFO("close, terminated connection to *MONITOR service\n");
 455
 456         atomic_set(&monpriv->iucv_severed, 0);
 457         atomic_set(&monpriv->iucv_connected, 0);
 458         atomic_set(&monpriv->read_ready, 0);
 459         atomic_set(&monpriv->msglim_count, 0);
 460         monpriv->write_index  = 0;
 461         monpriv->read_index   = 0;
 462
 463         for (i = 0; i < MON_MSGLIM; i++)
 464                 kfree(monpriv->msg_array[i]);
 465         kfree(monpriv);
 466         clear_bit(MON_IN_USE, &mon_in_use);
 467         return 0;
 468 }
 469
 470 static ssize_t mon_read(struct file *filp, char __user *data,
 471                         size_t count, loff_t *ppos)
 472 {
 473         struct mon_private *monpriv = filp->private_data;
 474         struct mon_msg *monmsg;
 475         int ret;
 476         u32 mce_start;
 477
 478         monmsg = mon_next_message(monpriv);
 479         if (IS_ERR(monmsg))
 480                 return PTR_ERR(monmsg);
 481
 482         if (!monmsg) {
 483                 if (filp->f_flags & O_NONBLOCK)
 484                         return -EAGAIN;
 485                 ret = wait_event_interruptible(mon_read_wait_queue,
 486                                         atomic_read(&monpriv->read_ready) ||
 487                                         atomic_read(&monpriv->iucv_severed));
 488                 if (ret)
 489                         return ret;
 490                 if (unlikely(atomic_read(&monpriv->iucv_severed)))
 491                         return -EIO;
 492                 monmsg = monpriv->msg_array[monpriv->read_index];
 493         }
 494
 495         if (!monmsg->pos) {
 496                 monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset;
 497                 mon_read_debug(monmsg, monpriv);
 498         }
 499         if (mon_check_mca(monmsg))
 500                 goto reply;
 501
 502         /* read monitor control element (12 bytes) first */
 503         mce_start = mon_mca_start(monmsg) + monmsg->mca_offset;
 504         if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) {
 505                 count = min(count, (size_t) mce_start + 12 - monmsg->pos);
 506                 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
 507                                    count);
 508                 if (ret)
 509                         return -EFAULT;
 510                 monmsg->pos += count;
 511                 if (monmsg->pos == mce_start + 12)
 512                         monmsg->pos = mon_rec_start(monmsg);
 513                 goto out_copy;
 514         }
 515
 516         /* read records */
 517         if (monmsg->pos <= mon_rec_end(monmsg)) {
 518                 count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos
 519                                             + 1);
 520                 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
 521                                    count);
 522                 if (ret)
 523                         return -EFAULT;
 524                 monmsg->pos += count;
 525                 if (monmsg->pos > mon_rec_end(monmsg))
 526                         mon_next_mca(monmsg);
 527                 goto out_copy;
 528         }
 529 reply:
 530         ret = mon_send_reply(monmsg, monpriv);
 531         return ret;
 532
 533 out_copy:
 534         *ppos += count;
 535         return count;
 536 }
 537
 538 static unsigned int mon_poll(struct file *filp, struct poll_table_struct *p)
 539 {
 540         struct mon_private *monpriv = filp->private_data;
 541
 542         poll_wait(filp, &mon_read_wait_queue, p);
 543         if (unlikely(atomic_read(&monpriv->iucv_severed)))
 544                 return POLLERR;
 545         if (atomic_read(&monpriv->read_ready))
 546                 return POLLIN | POLLRDNORM;
 547         return 0;
 548 }
 549
 550 static const struct file_operations mon_fops = {
 551         .owner   = THIS_MODULE,
 552         .open    = &mon_open,
 553         .release = &mon_close,
 554         .read    = &mon_read,
 555         .poll    = &mon_poll,
 556 };
 557
 558 static struct miscdevice mon_dev = {
 559         .name       = "monreader",
 560         .fops       = &mon_fops,
 561         .minor      = MISC_DYNAMIC_MINOR,
 562 };
 563
 564 /******************************************************************************
 565  *                              module init/exit                              *
 566  *****************************************************************************/
 567 static int __init mon_init(void)
 568 {
 569         int rc;
 570
 571         if (!MACHINE_IS_VM) {
 572                 P_ERROR("not running under z/VM, driver not loaded\n");
 573                 return -ENODEV;
 574         }
 575
 576         /*
 577          * Register with IUCV and connect to *MONITOR service
 578          */
 579         rc = iucv_register(&monreader_iucv_handler, 1);
 580         if (rc) {
 581                 P_ERROR("failed to register with iucv driver\n");
 582                 return rc;
 583         }
 584         P_INFO("open, registered with IUCV\n");
 585
 586         rc = segment_type(mon_dcss_name);
 587         if (rc < 0) {
 588                 mon_segment_warn(rc, mon_dcss_name);
 589                 goto out_iucv;
 590         }
 591         if (rc != SEG_TYPE_SC) {
 592                 P_ERROR("segment %s has unsupported type, should be SC\n",
 593                         mon_dcss_name);
 594                 rc = -EINVAL;
 595                 goto out_iucv;
 596         }
 597
 598         rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
 599                           &mon_dcss_start, &mon_dcss_end);
 600         if (rc < 0) {
 601                 mon_segment_warn(rc, mon_dcss_name);
 602                 rc = -EINVAL;
 603                 goto out_iucv;
 604         }
 605         dcss_mkname(mon_dcss_name, &user_data_connect[8]);
 606
 607         rc = misc_register(&mon_dev);
 608         if (rc < 0 ) {
 609                 P_ERROR("misc_register failed, rc = %i\n", rc);
 610                 goto out;
 611         }
 612         P_INFO("Loaded segment %s from %p to %p, size = %lu Byte\n",
 613                 mon_dcss_name, (void *) mon_dcss_start, (void *) mon_dcss_end,
 614                 mon_dcss_end - mon_dcss_start + 1);
 615         return 0;
 616
 617 out:
 618         segment_unload(mon_dcss_name);
 619 out_iucv:
 620         iucv_unregister(&monreader_iucv_handler, 1);
 621         return rc;
 622 }
 623
 624 static void __exit mon_exit(void)
 625 {
 626         segment_unload(mon_dcss_name);
 627         WARN_ON(misc_deregister(&mon_dev) != 0);
 628         iucv_unregister(&monreader_iucv_handler, 1);
 629         return;
 630 }
 631
 632
 633 module_init(mon_init);
 634 module_exit(mon_exit);
 635
 636 module_param_string(mondcss, mon_dcss_name, 9, 0444);
 637 MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR "
 638                  "service, max. 8 chars. Default is MONDCSS");
 639
 640 MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>");
 641 MODULE_DESCRIPTION("Character device driver for reading z/VM "
 642                    "monitor service records.");
 643 MODULE_LICENSE("GPL");