drivers/s390/block/dasd_diag.c

   1 /*
   2  * File...........: linux/drivers/s390/block/dasd_diag.c
   3  * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
   4  * Based on.......: linux/drivers/s390/block/mdisk.c
   5  * ...............: by Hartmunt Penner <hpenner@de.ibm.com>
   6  * Bugreports.to..: <Linux390@de.ibm.com>
   7  * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 1999,2000
   8  *
   9  * $Revision: 1.49 $
  10  */
  11
  12 #include <linux/config.h>
  13 #include <linux/stddef.h>
  14 #include <linux/kernel.h>
  15 #include <linux/slab.h>
  16 #include <linux/hdreg.h>
  17 #include <linux/bio.h>
  18 #include <linux/module.h>
  19 #include <linux/init.h>
  20 #include <linux/jiffies.h>
  21
  22 #include <asm/dasd.h>
  23 #include <asm/debug.h>
  24 #include <asm/ebcdic.h>
  25 #include <asm/io.h>
  26 #include <asm/s390_ext.h>
  27 #include <asm/todclk.h>
  28
  29 #include "dasd_int.h"
  30 #include "dasd_diag.h"
  31
  32 #define PRINTK_HEADER "dasd(diag):"
  33
  34 MODULE_LICENSE("GPL");
  35
  36 /* The maximum number of blocks per request (max_blocks) is dependent on the
  37  * amount of storage that is available in the static I/O buffer for each
  38  * device. Currently each device gets 2 pages. We want to fit two requests
  39  * into the available memory so that we can immediately start the next if one
  40  * finishes. */
  41 #define DIAG_MAX_BLOCKS (((2 * PAGE_SIZE - sizeof(struct dasd_ccw_req) - \
  42                            sizeof(struct dasd_diag_req)) / \
  43                            sizeof(struct dasd_diag_bio)) / 2)
  44 #define DIAG_MAX_RETRIES        32
  45 #define DIAG_TIMEOUT            50 * HZ
  46
  47 struct dasd_discipline dasd_diag_discipline;
  48
  49 struct dasd_diag_private {
  50         struct dasd_diag_characteristics rdc_data;
  51         struct dasd_diag_rw_io iob;
  52         struct dasd_diag_init_io iib;
  53         blocknum_t pt_block;
  54 };
  55
  56 struct dasd_diag_req {
  57         unsigned int block_count;
  58         struct dasd_diag_bio bio[0];
  59 };
  60
  61 static const u8 DASD_DIAG_CMS1[] = { 0xc3, 0xd4, 0xe2, 0xf1 };/* EBCDIC CMS1 */
  62
  63 /* Perform DIAG250 call with block I/O parameter list iob (input and output)
  64  * and function code cmd.
  65  * In case of an exception return 3. Otherwise return result of bitwise OR of
  66  * resulting condition code and DIAG return code. */
  67 static __inline__ int
  68 dia250(void *iob, int cmd)
  69 {
  70         typedef struct {
  71                 char _[max(sizeof (struct dasd_diag_init_io),
  72                            sizeof (struct dasd_diag_rw_io))];
  73         } addr_type;
  74         int rc;
  75
  76         __asm__ __volatile__(
  77 #ifdef CONFIG_ARCH_S390X
  78                 "       lghi    %0,3\n"
  79                 "       lgr     0,%3\n"
  80                 "       diag    0,%2,0x250\n"
  81                 "0:     ipm     %0\n"
  82                 "       srl     %0,28\n"
  83                 "       or      %0,1\n"
  84                 "1:\n"
  85                 ".section __ex_table,\"a\"\n"
  86                 "       .align 8\n"
  87                 "       .quad  0b,1b\n"
  88                 ".previous\n"
  89 #else
  90                 "       lhi     %0,3\n"
  91                 "       lr      0,%3\n"
  92                 "       diag    0,%2,0x250\n"
  93                 "0:     ipm     %0\n"
  94                 "       srl     %0,28\n"
  95                 "       or      %0,1\n"
  96                 "1:\n"
  97                 ".section __ex_table,\"a\"\n"
  98                 "       .align 4\n"
  99                 "       .long 0b,1b\n"
 100                 ".previous\n"
 101 #endif
 102                 : "=&d" (rc), "=m" (*(addr_type *) iob)
 103                 : "d" (cmd), "d" (iob), "m" (*(addr_type *) iob)
 104                 : "0", "1", "cc");
 105         return rc;
 106 }
 107
 108 /* Initialize block I/O to DIAG device using the specified blocksize and
 109  * block offset. On success, return zero and set end_block to contain the
 110  * number of blocks on the device minus the specified offset. Return non-zero
 111  * otherwise. */
 112 static __inline__ int
 113 mdsk_init_io(struct dasd_device *device, unsigned int blocksize,
 114              blocknum_t offset, blocknum_t *end_block)
 115 {
 116         struct dasd_diag_private *private;
 117         struct dasd_diag_init_io *iib;
 118         int rc;
 119
 120         private = (struct dasd_diag_private *) device->private;
 121         iib = &private->iib;
 122         memset(iib, 0, sizeof (struct dasd_diag_init_io));
 123
 124         iib->dev_nr = _ccw_device_get_device_number(device->cdev);
 125         iib->block_size = blocksize;
 126         iib->offset = offset;
 127         iib->flaga = DASD_DIAG_FLAGA_DEFAULT;
 128
 129         rc = dia250(iib, INIT_BIO);
 130
 131         if ((rc & 3) == 0 && end_block)
 132                 *end_block = iib->end_block;
 133
 134         return rc;
 135 }
 136
 137 /* Remove block I/O environment for device. Return zero on success, non-zero
 138  * otherwise. */
 139 static __inline__ int
 140 mdsk_term_io(struct dasd_device * device)
 141 {
 142         struct dasd_diag_private *private;
 143         struct dasd_diag_init_io *iib;
 144         int rc;
 145
 146         private = (struct dasd_diag_private *) device->private;
 147         iib = &private->iib;
 148         memset(iib, 0, sizeof (struct dasd_diag_init_io));
 149         iib->dev_nr = _ccw_device_get_device_number(device->cdev);
 150         rc = dia250(iib, TERM_BIO);
 151         return rc;
 152 }
 153
 154 /* Error recovery for failed DIAG requests - try to reestablish the DIAG
 155  * environment. */
 156 static void
 157 dasd_diag_erp(struct dasd_device *device)
 158 {
 159         int rc;
 160
 161         mdsk_term_io(device);
 162         rc = mdsk_init_io(device, device->bp_block, 0, NULL);
 163         if (rc)
 164                 DEV_MESSAGE(KERN_WARNING, device, "DIAG ERP unsuccessful, "
 165                             "rc=%d", rc);
 166 }
 167
 168 /* Start a given request at the device. Return zero on success, non-zero
 169  * otherwise. */
 170 static int
 171 dasd_start_diag(struct dasd_ccw_req * cqr)
 172 {
 173         struct dasd_device *device;
 174         struct dasd_diag_private *private;
 175         struct dasd_diag_req *dreq;
 176         int rc;
 177
 178         device = cqr->device;
 179         if (cqr->retries < 0) {
 180                 DEV_MESSAGE(KERN_WARNING, device, "DIAG start_IO: request %p "
 181                             "- no retry left)", cqr);
 182                 cqr->status = DASD_CQR_FAILED;
 183                 return -EIO;
 184         }
 185         private = (struct dasd_diag_private *) device->private;
 186         dreq = (struct dasd_diag_req *) cqr->data;
 187
 188         private->iob.dev_nr = _ccw_device_get_device_number(device->cdev);
 189         private->iob.key = 0;
 190         private->iob.flags = DASD_DIAG_RWFLAG_ASYNC;
 191         private->iob.block_count = dreq->block_count;
 192         private->iob.interrupt_params = (addr_t) cqr;
 193         private->iob.bio_list = __pa(dreq->bio);
 194         private->iob.flaga = DASD_DIAG_FLAGA_DEFAULT;
 195
 196         cqr->startclk = get_clock();
 197         cqr->starttime = jiffies;
 198         cqr->retries--;
 199
 200         rc = dia250(&private->iob, RW_BIO);
 201         switch (rc) {
 202         case 0: /* Synchronous I/O finished successfully */
 203                 cqr->stopclk = get_clock();
 204                 cqr->status = DASD_CQR_DONE;
 205                 /* Indicate to calling function that only a dasd_schedule_bh()
 206                    and no timer is needed */
 207                 rc = -EACCES;
 208                 break;
 209         case 8: /* Asynchronous I/O was started */
 210                 cqr->status = DASD_CQR_IN_IO;
 211                 rc = 0;
 212                 break;
 213         default: /* Error condition */
 214                 cqr->status = DASD_CQR_QUEUED;
 215                 DEV_MESSAGE(KERN_WARNING, device, "dia250 returned rc=%d", rc);
 216                 dasd_diag_erp(device);
 217                 rc = -EIO;
 218                 break;
 219         }
 220         return rc;
 221 }
 222
 223 /* Terminate given request at the device. */
 224 static int
 225 dasd_diag_term_IO(struct dasd_ccw_req * cqr)
 226 {
 227         struct dasd_device *device;
 228
 229         device = cqr->device;
 230         mdsk_term_io(device);
 231         mdsk_init_io(device, device->bp_block, 0, NULL);
 232         cqr->status = DASD_CQR_CLEAR;
 233         cqr->stopclk = get_clock();
 234         dasd_schedule_bh(device);
 235         return 0;
 236 }
 237
 238 /* Handle external interruption. */
 239 static void
 240 dasd_ext_handler(struct pt_regs *regs, __u16 code)
 241 {
 242         struct dasd_ccw_req *cqr, *next;
 243         struct dasd_device *device;
 244         unsigned long long expires;
 245         unsigned long flags;
 246         u8 int_code, status;
 247         addr_t ip;
 248         int rc;
 249
 250         int_code = *((u8 *) DASD_DIAG_LC_INT_CODE);
 251         status = *((u8 *) DASD_DIAG_LC_INT_STATUS);
 252         switch (int_code) {
 253         case DASD_DIAG_CODE_31BIT:
 254                 ip = (addr_t) *((u32 *) DASD_DIAG_LC_INT_PARM_31BIT);
 255                 break;
 256         case DASD_DIAG_CODE_64BIT:
 257                 ip = (addr_t) *((u64 *) DASD_DIAG_LC_INT_PARM_64BIT);
 258                 break;
 259         default:
 260                 return;
 261         }
 262         if (!ip) {              /* no intparm: unsolicited interrupt */
 263                 MESSAGE(KERN_DEBUG, "%s", "caught unsolicited interrupt");
 264                 return;
 265         }
 266         cqr = (struct dasd_ccw_req *) ip;
 267         device = (struct dasd_device *) cqr->device;
 268         if (strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
 269                 DEV_MESSAGE(KERN_WARNING, device,
 270                             " magic number of dasd_ccw_req 0x%08X doesn't"
 271                             " match discipline 0x%08X",
 272                             cqr->magic, *(int *) (&device->discipline->name));
 273                 return;
 274         }
 275
 276         /* get irq lock to modify request queue */
 277         spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 278
 279         /* Check for a pending clear operation */
 280         if (cqr->status == DASD_CQR_CLEAR) {
 281                 cqr->status = DASD_CQR_QUEUED;
 282                 dasd_clear_timer(device);
 283                 dasd_schedule_bh(device);
 284                 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 285                 return;
 286         }
 287
 288         cqr->stopclk = get_clock();
 289
 290         expires = 0;
 291         if (status == 0) {
 292                 cqr->status = DASD_CQR_DONE;
 293                 /* Start first request on queue if possible -> fast_io. */
 294                 if (!list_empty(&device->ccw_queue)) {
 295                         next = list_entry(device->ccw_queue.next,
 296                                           struct dasd_ccw_req, list);
 297                         if (next->status == DASD_CQR_QUEUED) {
 298                                 rc = dasd_start_diag(next);
 299                                 if (rc == 0)
 300                                         expires = next->expires;
 301                                 else if (rc != -EACCES)
 302                                         DEV_MESSAGE(KERN_WARNING, device, "%s",
 303                                                     "Interrupt fastpath "
 304                                                     "failed!");
 305                         }
 306                 }
 307         } else {
 308                 cqr->status = DASD_CQR_QUEUED;
 309                 DEV_MESSAGE(KERN_WARNING, device, "interrupt status for "
 310                             "request %p was %d (%d retries left)", cqr, status,
 311                             cqr->retries);
 312                 dasd_diag_erp(device);
 313         }
 314
 315         if (expires != 0)
 316                 dasd_set_timer(device, expires);
 317         else
 318                 dasd_clear_timer(device);
 319         dasd_schedule_bh(device);
 320
 321         spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 322 }
 323
 324 /* Check whether device can be controlled by DIAG discipline. Return zero on
 325  * success, non-zero otherwise. */
 326 static int
 327 dasd_diag_check_device(struct dasd_device *device)
 328 {
 329         struct dasd_diag_private *private;
 330         struct dasd_diag_characteristics *rdc_data;
 331         struct dasd_diag_bio bio;
 332         struct dasd_diag_cms_label *label;
 333         blocknum_t end_block;
 334         unsigned int sb, bsize;
 335         int rc;
 336
 337         private = (struct dasd_diag_private *) device->private;
 338         if (private == NULL) {
 339                 private = kmalloc(sizeof(struct dasd_diag_private),GFP_KERNEL);
 340                 if (private == NULL) {
 341                         DEV_MESSAGE(KERN_WARNING, device, "%s",
 342                                 "memory allocation failed for private data");
 343                         return -ENOMEM;
 344                 }
 345                 device->private = (void *) private;
 346         }
 347         /* Read Device Characteristics */
 348         rdc_data = (void *) &(private->rdc_data);
 349         rdc_data->dev_nr = _ccw_device_get_device_number(device->cdev);
 350         rdc_data->rdc_len = sizeof (struct dasd_diag_characteristics);
 351
 352         rc = diag210((struct diag210 *) rdc_data);
 353         if (rc) {
 354                 DEV_MESSAGE(KERN_WARNING, device, "failed to retrieve device "
 355                             "information (rc=%d)", rc);
 356                 return -ENOTSUPP;
 357         }
 358
 359         /* Figure out position of label block */
 360         switch (private->rdc_data.vdev_class) {
 361         case DEV_CLASS_FBA:
 362                 private->pt_block = 1;
 363                 break;
 364         case DEV_CLASS_ECKD:
 365                 private->pt_block = 2;
 366                 break;
 367         default:
 368                 DEV_MESSAGE(KERN_WARNING, device, "unsupported device class "
 369                             "(class=%d)", private->rdc_data.vdev_class);
 370                 return -ENOTSUPP;
 371         }
 372
 373         DBF_DEV_EVENT(DBF_INFO, device,
 374                       "%04X: %04X on real %04X/%02X",
 375                       rdc_data->dev_nr,
 376                       rdc_data->vdev_type,
 377                       rdc_data->rdev_type, rdc_data->rdev_model);
 378
 379         /* terminate all outstanding operations */
 380         mdsk_term_io(device);
 381
 382         /* figure out blocksize of device */
 383         label = (struct dasd_diag_cms_label *) get_zeroed_page(GFP_KERNEL);
 384         if (label == NULL)  {
 385                 DEV_MESSAGE(KERN_WARNING, device, "%s",
 386                             "No memory to allocate initialization request");
 387                 return -ENOMEM;
 388         }
 389         rc = 0;
 390         end_block = 0;
 391         /* try all sizes - needed for ECKD devices */
 392         for (bsize = 512; bsize <= PAGE_SIZE; bsize <<= 1) {
 393                 mdsk_init_io(device, bsize, 0, &end_block);
 394                 memset(&bio, 0, sizeof (struct dasd_diag_bio));
 395                 bio.type = MDSK_READ_REQ;
 396                 bio.block_number = private->pt_block + 1;
 397                 bio.buffer = __pa(label);
 398                 memset(&private->iob, 0, sizeof (struct dasd_diag_rw_io));
 399                 private->iob.dev_nr = rdc_data->dev_nr;
 400                 private->iob.key = 0;
 401                 private->iob.flags = 0; /* do synchronous io */
 402                 private->iob.block_count = 1;
 403                 private->iob.interrupt_params = 0;
 404                 private->iob.bio_list = __pa(&bio);
 405                 private->iob.flaga = DASD_DIAG_FLAGA_DEFAULT;
 406                 rc = dia250(&private->iob, RW_BIO);
 407                 if (rc == 0 || rc == 3)
 408                         break;
 409                 mdsk_term_io(device);
 410         }
 411         if (rc == 3) {
 412                 DEV_MESSAGE(KERN_WARNING, device, "%s", "DIAG call failed");
 413                 rc = -EOPNOTSUPP;
 414         } else if (rc != 0) {
 415                 DEV_MESSAGE(KERN_WARNING, device, "device access failed "
 416                             "(rc=%d)", rc);
 417                 rc = -EIO;
 418         } else {
 419                 if (memcmp(label->label_id, DASD_DIAG_CMS1,
 420                           sizeof(DASD_DIAG_CMS1)) == 0) {
 421                         /* get formatted blocksize from label block */
 422                         bsize = (unsigned int) label->block_size;
 423                         device->blocks = (unsigned long) label->block_count;
 424                 } else
 425                         device->blocks = end_block;
 426                 device->bp_block = bsize;
 427                 device->s2b_shift = 0;  /* bits to shift 512 to get a block */
 428                 for (sb = 512; sb < bsize; sb = sb << 1)
 429                         device->s2b_shift++;
 430
 431                 DEV_MESSAGE(KERN_INFO, device,
 432                             "(%ld B/blk): %ldkB",
 433                             (unsigned long) device->bp_block,
 434                             (unsigned long) (device->blocks <<
 435                                 device->s2b_shift) >> 1);
 436                 rc = 0;
 437         }
 438         free_page((long) label);
 439         return rc;
 440 }
 441
 442 /* Fill in virtual disk geometry for device. Return zero on success, non-zero
 443  * otherwise. */
 444 static int
 445 dasd_diag_fill_geometry(struct dasd_device *device, struct hd_geometry *geo)
 446 {
 447         if (dasd_check_blocksize(device->bp_block) != 0)
 448                 return -EINVAL;
 449         geo->cylinders = (device->blocks << device->s2b_shift) >> 10;
 450         geo->heads = 16;
 451         geo->sectors = 128 >> device->s2b_shift;
 452         return 0;
 453 }
 454
 455 static dasd_era_t
 456 dasd_diag_examine_error(struct dasd_ccw_req * cqr, struct irb * stat)
 457 {
 458         return dasd_era_fatal;
 459 }
 460
 461 static dasd_erp_fn_t
 462 dasd_diag_erp_action(struct dasd_ccw_req * cqr)
 463 {
 464         return dasd_default_erp_action;
 465 }
 466
 467 static dasd_erp_fn_t
 468 dasd_diag_erp_postaction(struct dasd_ccw_req * cqr)
 469 {
 470         return dasd_default_erp_postaction;
 471 }
 472
 473 /* Create DASD request from block device request. Return pointer to new
 474  * request on success, ERR_PTR otherwise. */
 475 static struct dasd_ccw_req *
 476 dasd_diag_build_cp(struct dasd_device * device, struct request *req)
 477 {
 478         struct dasd_ccw_req *cqr;
 479         struct dasd_diag_req *dreq;
 480         struct dasd_diag_bio *dbio;
 481         struct bio *bio;
 482         struct bio_vec *bv;
 483         char *dst;
 484         unsigned int count, datasize;
 485         sector_t recid, first_rec, last_rec;
 486         unsigned int blksize, off;
 487         unsigned char rw_cmd;
 488         int i;
 489
 490         if (rq_data_dir(req) == READ)
 491                 rw_cmd = MDSK_READ_REQ;
 492         else if (rq_data_dir(req) == WRITE)
 493                 rw_cmd = MDSK_WRITE_REQ;
 494         else
 495                 return ERR_PTR(-EINVAL);
 496         blksize = device->bp_block;
 497         /* Calculate record id of first and last block. */
 498         first_rec = req->sector >> device->s2b_shift;
 499         last_rec = (req->sector + req->nr_sectors - 1) >> device->s2b_shift;
 500         /* Check struct bio and count the number of blocks for the request. */
 501         count = 0;
 502         rq_for_each_bio(bio, req) {
 503                 bio_for_each_segment(bv, bio, i) {
 504                         if (bv->bv_len & (blksize - 1))
 505                                 /* Fba can only do full blocks. */
 506                                 return ERR_PTR(-EINVAL);
 507                         count += bv->bv_len >> (device->s2b_shift + 9);
 508                 }
 509         }
 510         /* Paranoia. */
 511         if (count != last_rec - first_rec + 1)
 512                 return ERR_PTR(-EINVAL);
 513         /* Build the request */
 514         datasize = sizeof(struct dasd_diag_req) +
 515                 count*sizeof(struct dasd_diag_bio);
 516         cqr = dasd_smalloc_request(dasd_diag_discipline.name, 0,
 517                                    datasize, device);
 518         if (IS_ERR(cqr))
 519                 return cqr;
 520
 521         dreq = (struct dasd_diag_req *) cqr->data;
 522         dreq->block_count = count;
 523         dbio = dreq->bio;
 524         recid = first_rec;
 525         rq_for_each_bio(bio, req) {
 526                 bio_for_each_segment(bv, bio, i) {
 527                         dst = page_address(bv->bv_page) + bv->bv_offset;
 528                         for (off = 0; off < bv->bv_len; off += blksize) {
 529                                 memset(dbio, 0, sizeof (struct dasd_diag_bio));
 530                                 dbio->type = rw_cmd;
 531                                 dbio->block_number = recid + 1;
 532                                 dbio->buffer = __pa(dst);
 533                                 dbio++;
 534                                 dst += blksize;
 535                                 recid++;
 536                         }
 537                 }
 538         }
 539         cqr->retries = DIAG_MAX_RETRIES;
 540         cqr->buildclk = get_clock();
 541         cqr->device = device;
 542         cqr->expires = DIAG_TIMEOUT;
 543         cqr->status = DASD_CQR_FILLED;
 544         return cqr;
 545 }
 546
 547 /* Release DASD request. Return non-zero if request was successful, zero
 548  * otherwise. */
 549 static int
 550 dasd_diag_free_cp(struct dasd_ccw_req *cqr, struct request *req)
 551 {
 552         int status;
 553
 554         status = cqr->status == DASD_CQR_DONE;
 555         dasd_sfree_request(cqr, cqr->device);
 556         return status;
 557 }
 558
 559 /* Fill in IOCTL data for device. */
 560 static int
 561 dasd_diag_fill_info(struct dasd_device * device,
 562                     struct dasd_information2_t * info)
 563 {
 564         struct dasd_diag_private *private;
 565
 566         private = (struct dasd_diag_private *) device->private;
 567         info->label_block = (unsigned int) private->pt_block;
 568         info->FBA_layout = 1;
 569         info->format = DASD_FORMAT_LDL;
 570         info->characteristics_size = sizeof (struct dasd_diag_characteristics);
 571         memcpy(info->characteristics,
 572                &((struct dasd_diag_private *) device->private)->rdc_data,
 573                sizeof (struct dasd_diag_characteristics));
 574         info->confdata_size = 0;
 575         return 0;
 576 }
 577
 578 static void
 579 dasd_diag_dump_sense(struct dasd_device *device, struct dasd_ccw_req * req,
 580                      struct irb *stat)
 581 {
 582         DEV_MESSAGE(KERN_ERR, device, "%s",
 583                     "dump sense not available for DIAG data");
 584 }
 585
 586 struct dasd_discipline dasd_diag_discipline = {
 587         .owner = THIS_MODULE,
 588         .name = "DIAG",
 589         .ebcname = "DIAG",
 590         .max_blocks = DIAG_MAX_BLOCKS,
 591         .check_device = dasd_diag_check_device,
 592         .fill_geometry = dasd_diag_fill_geometry,
 593         .start_IO = dasd_start_diag,
 594         .term_IO = dasd_diag_term_IO,
 595         .examine_error = dasd_diag_examine_error,
 596         .erp_action = dasd_diag_erp_action,
 597         .erp_postaction = dasd_diag_erp_postaction,
 598         .build_cp = dasd_diag_build_cp,
 599         .free_cp = dasd_diag_free_cp,
 600         .dump_sense = dasd_diag_dump_sense,
 601         .fill_info = dasd_diag_fill_info,
 602 };
 603
 604 static int __init
 605 dasd_diag_init(void)
 606 {
 607         if (!MACHINE_IS_VM) {
 608                 MESSAGE_LOG(KERN_INFO,
 609                             "Machine is not VM: %s "
 610                             "discipline not initializing",
 611                             dasd_diag_discipline.name);
 612                 return -ENODEV;
 613         }
 614         ASCEBC(dasd_diag_discipline.ebcname, 4);
 615
 616         ctl_set_bit(0, 9);
 617         register_external_interrupt(0x2603, dasd_ext_handler);
 618         dasd_diag_discipline_pointer = &dasd_diag_discipline;
 619         return 0;
 620 }
 621
 622 static void __exit
 623 dasd_diag_cleanup(void)
 624 {
 625         unregister_external_interrupt(0x2603, dasd_ext_handler);
 626         ctl_clear_bit(0, 9);
 627         dasd_diag_discipline_pointer = NULL;
 628 }
 629
 630 module_init(dasd_diag_init);
 631 module_exit(dasd_diag_cleanup);