drivers/s390/char/vmlogrdr.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *      character device driver for reading z/VM system service records
   4  *
   5  *
   6  *      Copyright IBM Corp. 2004, 2009
   7  *      character device driver for reading z/VM system service records,
   8  *      Version 1.0
   9  *      Author(s): Xenia Tkatschow <xenia@us.ibm.com>
  10  *                 Stefan Weinhuber <wein@de.ibm.com>
  11  *
  12  */
  13
  14 #define KMSG_COMPONENT "vmlogrdr"
  15 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  16
  17 #include <linux/module.h>
  18 #include <linux/init.h>
  19 #include <linux/slab.h>
  20 #include <linux/errno.h>
  21 #include <linux/types.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/atomic.h>
  25 #include <linux/uaccess.h>
  26 #include <asm/cpcmd.h>
  27 #include <asm/debug.h>
  28 #include <asm/ebcdic.h>
  29 #include <net/iucv/iucv.h>
  30 #include <linux/kmod.h>
  31 #include <linux/cdev.h>
  32 #include <linux/device.h>
  33 #include <linux/string.h>
  34
  35 MODULE_AUTHOR
  36         ("(C) 2004 IBM Corporation by Xenia Tkatschow (xenia@us.ibm.com)\n"
  37          "                            Stefan Weinhuber (wein@de.ibm.com)");
  38 MODULE_DESCRIPTION ("Character device driver for reading z/VM "
  39                     "system service records.");
  40 MODULE_LICENSE("GPL");
  41
  42
  43 /*
  44  * The size of the buffer for iucv data transfer is one page,
  45  * but in addition to the data we read from iucv we also
  46  * place an integer and some characters into that buffer,
  47  * so the maximum size for record data is a little less then
  48  * one page.
  49  */
  50 #define NET_BUFFER_SIZE (PAGE_SIZE - sizeof(int) - sizeof(FENCE))
  51
  52 /*
  53  * The elements that are concurrently accessed by bottom halves are
  54  * connection_established, iucv_path_severed, local_interrupt_buffer
  55  * and receive_ready. The first three can be protected by
  56  * priv_lock.  receive_ready is atomic, so it can be incremented and
  57  * decremented without holding a lock.
  58  * The variable dev_in_use needs to be protected by the lock, since
  59  * it's a flag used by open to make sure that the device is opened only
  60  * by one user at the same time.
  61  */
  62 struct vmlogrdr_priv_t {
  63         char system_service[8];
  64         char internal_name[8];
  65         char recording_name[8];
  66         struct iucv_path *path;
  67         int connection_established;
  68         int iucv_path_severed;
  69         struct iucv_message local_interrupt_buffer;
  70         atomic_t receive_ready;
  71         int minor_num;
  72         char * buffer;
  73         char * current_position;
  74         int remaining;
  75         ulong residual_length;
  76         int buffer_free;
  77         int dev_in_use; /* 1: already opened, 0: not opened*/
  78         spinlock_t priv_lock;
  79         struct device  *device;
  80         struct device  *class_device;
  81         int autorecording;
  82         int autopurge;
  83 };
  84
  85
  86 /*
  87  * File operation structure for vmlogrdr devices
  88  */
  89 static int vmlogrdr_open(struct inode *, struct file *);
  90 static int vmlogrdr_release(struct inode *, struct file *);
  91 static ssize_t vmlogrdr_read (struct file *filp, char __user *data,
  92                               size_t count, loff_t * ppos);
  93
  94 static const struct file_operations vmlogrdr_fops = {
  95         .owner   = THIS_MODULE,
  96         .open    = vmlogrdr_open,
  97         .release = vmlogrdr_release,
  98         .read    = vmlogrdr_read,
  99         .llseek  = no_llseek,
 100 };
 101
 102
 103 static void vmlogrdr_iucv_path_complete(struct iucv_path *, u8 *ipuser);
 104 static void vmlogrdr_iucv_path_severed(struct iucv_path *, u8 *ipuser);
 105 static void vmlogrdr_iucv_message_pending(struct iucv_path *,
 106                                           struct iucv_message *);
 107
 108
 109 static struct iucv_handler vmlogrdr_iucv_handler = {
 110         .path_complete   = vmlogrdr_iucv_path_complete,
 111         .path_severed    = vmlogrdr_iucv_path_severed,
 112         .message_pending = vmlogrdr_iucv_message_pending,
 113 };
 114
 115
 116 static DECLARE_WAIT_QUEUE_HEAD(conn_wait_queue);
 117 static DECLARE_WAIT_QUEUE_HEAD(read_wait_queue);
 118
 119 /*
 120  * pointer to system service private structure
 121  * minor number 0 --> logrec
 122  * minor number 1 --> account
 123  * minor number 2 --> symptom
 124  */
 125
 126 static struct vmlogrdr_priv_t sys_ser[] = {
 127         { .system_service = "*LOGREC ",
 128           .internal_name  = "logrec",
 129           .recording_name = "EREP",
 130           .minor_num      = 0,
 131           .buffer_free    = 1,
 132           .priv_lock      = __SPIN_LOCK_UNLOCKED(sys_ser[0].priv_lock),
 133           .autorecording  = 1,
 134           .autopurge      = 1,
 135         },
 136         { .system_service = "*ACCOUNT",
 137           .internal_name  = "account",
 138           .recording_name = "ACCOUNT",
 139           .minor_num      = 1,
 140           .buffer_free    = 1,
 141           .priv_lock      = __SPIN_LOCK_UNLOCKED(sys_ser[1].priv_lock),
 142           .autorecording  = 1,
 143           .autopurge      = 1,
 144         },
 145         { .system_service = "*SYMPTOM",
 146           .internal_name  = "symptom",
 147           .recording_name = "SYMPTOM",
 148           .minor_num      = 2,
 149           .buffer_free    = 1,
 150           .priv_lock      = __SPIN_LOCK_UNLOCKED(sys_ser[2].priv_lock),
 151           .autorecording  = 1,
 152           .autopurge      = 1,
 153         }
 154 };
 155
 156 #define MAXMINOR  (sizeof(sys_ser)/sizeof(struct vmlogrdr_priv_t))
 157
 158 static char FENCE[] = {"EOR"};
 159 static int vmlogrdr_major = 0;
 160 static struct cdev  *vmlogrdr_cdev = NULL;
 161 static int recording_class_AB;
 162
 163
 164 static void vmlogrdr_iucv_path_complete(struct iucv_path *path, u8 *ipuser)
 165 {
 166         struct vmlogrdr_priv_t * logptr = path->private;
 167
 168         spin_lock(&logptr->priv_lock);
 169         logptr->connection_established = 1;
 170         spin_unlock(&logptr->priv_lock);
 171         wake_up(&conn_wait_queue);
 172 }
 173
 174
 175 static void vmlogrdr_iucv_path_severed(struct iucv_path *path, u8 *ipuser)
 176 {
 177         struct vmlogrdr_priv_t * logptr = path->private;
 178         u8 reason = (u8) ipuser[8];
 179
 180         pr_err("vmlogrdr: connection severed with reason %i\n", reason);
 181
 182         iucv_path_sever(path, NULL);
 183         kfree(path);
 184         logptr->path = NULL;
 185
 186         spin_lock(&logptr->priv_lock);
 187         logptr->connection_established = 0;
 188         logptr->iucv_path_severed = 1;
 189         spin_unlock(&logptr->priv_lock);
 190
 191         wake_up(&conn_wait_queue);
 192         /* just in case we're sleeping waiting for a record */
 193         wake_up_interruptible(&read_wait_queue);
 194 }
 195
 196
 197 static void vmlogrdr_iucv_message_pending(struct iucv_path *path,
 198                                           struct iucv_message *msg)
 199 {
 200         struct vmlogrdr_priv_t * logptr = path->private;
 201
 202         /*
 203          * This function is the bottom half so it should be quick.
 204          * Copy the external interrupt data into our local eib and increment
 205          * the usage count
 206          */
 207         spin_lock(&logptr->priv_lock);
 208         memcpy(&logptr->local_interrupt_buffer, msg, sizeof(*msg));
 209         atomic_inc(&logptr->receive_ready);
 210         spin_unlock(&logptr->priv_lock);
 211         wake_up_interruptible(&read_wait_queue);
 212 }
 213
 214
 215 static int vmlogrdr_get_recording_class_AB(void)
 216 {
 217         static const char cp_command[] = "QUERY COMMAND RECORDING ";
 218         char cp_response[80];
 219         char *tail;
 220         int len,i;
 221
 222         cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
 223         len = strnlen(cp_response,sizeof(cp_response));
 224         // now the parsing
 225         tail=strnchr(cp_response,len,'=');
 226         if (!tail)
 227                 return 0;
 228         tail++;
 229         if (!strncmp("ANY",tail,3))
 230                 return 1;
 231         if (!strncmp("NONE",tail,4))
 232                 return 0;
 233         /*
 234          * expect comma separated list of classes here, if one of them
 235          * is A or B return 1 otherwise 0
 236          */
 237         for (i=tail-cp_response; i<len; i++)
 238                 if ( cp_response[i]=='A' || cp_response[i]=='B' )
 239                         return 1;
 240         return 0;
 241 }
 242
 243
 244 static int vmlogrdr_recording(struct vmlogrdr_priv_t * logptr,
 245                               int action, int purge)
 246 {
 247
 248         char cp_command[80];
 249         char cp_response[160];
 250         char *onoff, *qid_string;
 251         int rc;
 252
 253         onoff = ((action == 1) ? "ON" : "OFF");
 254         qid_string = ((recording_class_AB == 1) ? " QID * " : "");
 255
 256         /*
 257          * The recording commands needs to be called with option QID
 258          * for guests that have previlege classes A or B.
 259          * Purging has to be done as separate step, because recording
 260          * can't be switched on as long as records are on the queue.
 261          * Doing both at the same time doesn't work.
 262          */
 263         if (purge && (action == 1)) {
 264                 memset(cp_command, 0x00, sizeof(cp_command));
 265                 memset(cp_response, 0x00, sizeof(cp_response));
 266                 snprintf(cp_command, sizeof(cp_command),
 267                          "RECORDING %s PURGE %s",
 268                          logptr->recording_name,
 269                          qid_string);
 270                 cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
 271         }
 272
 273         memset(cp_command, 0x00, sizeof(cp_command));
 274         memset(cp_response, 0x00, sizeof(cp_response));
 275         snprintf(cp_command, sizeof(cp_command), "RECORDING %s %s %s",
 276                 logptr->recording_name,
 277                 onoff,
 278                 qid_string);
 279         cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
 280         /* The recording command will usually answer with 'Command complete'
 281          * on success, but when the specific service was never connected
 282          * before then there might be an additional informational message
 283          * 'HCPCRC8072I Recording entry not found' before the
 284          * 'Command complete'. So I use strstr rather then the strncmp.
 285          */
 286         if (strstr(cp_response,"Command complete"))
 287                 rc = 0;
 288         else
 289                 rc = -EIO;
 290         /*
 291          * If we turn recording off, we have to purge any remaining records
 292          * afterwards, as a large number of queued records may impact z/VM
 293          * performance.
 294          */
 295         if (purge && (action == 0)) {
 296                 memset(cp_command, 0x00, sizeof(cp_command));
 297                 memset(cp_response, 0x00, sizeof(cp_response));
 298                 snprintf(cp_command, sizeof(cp_command),
 299                          "RECORDING %s PURGE %s",
 300                          logptr->recording_name,
 301                          qid_string);
 302                 cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
 303         }
 304
 305         return rc;
 306 }
 307
 308
 309 static int vmlogrdr_open (struct inode *inode, struct file *filp)
 310 {
 311         int dev_num = 0;
 312         struct vmlogrdr_priv_t * logptr = NULL;
 313         int connect_rc = 0;
 314         int ret;
 315
 316         dev_num = iminor(inode);
 317         if (dev_num >= MAXMINOR)
 318                 return -ENODEV;
 319         logptr = &sys_ser[dev_num];
 320
 321         /*
 322          * only allow for blocking reads to be open
 323          */
 324         if (filp->f_flags & O_NONBLOCK)
 325                 return -EOPNOTSUPP;
 326
 327         /* Besure this device hasn't already been opened */
 328         spin_lock_bh(&logptr->priv_lock);
 329         if (logptr->dev_in_use) {
 330                 spin_unlock_bh(&logptr->priv_lock);
 331                 return -EBUSY;
 332         }
 333         logptr->dev_in_use = 1;
 334         logptr->connection_established = 0;
 335         logptr->iucv_path_severed = 0;
 336         atomic_set(&logptr->receive_ready, 0);
 337         logptr->buffer_free = 1;
 338         spin_unlock_bh(&logptr->priv_lock);
 339
 340         /* set the file options */
 341         filp->private_data = logptr;
 342
 343         /* start recording for this service*/
 344         if (logptr->autorecording) {
 345                 ret = vmlogrdr_recording(logptr,1,logptr->autopurge);
 346                 if (ret)
 347                         pr_warn("vmlogrdr: failed to start recording automatically\n");
 348         }
 349
 350         /* create connection to the system service */
 351         logptr->path = iucv_path_alloc(10, 0, GFP_KERNEL);
 352         if (!logptr->path)
 353                 goto out_dev;
 354         connect_rc = iucv_path_connect(logptr->path, &vmlogrdr_iucv_handler,
 355                                        logptr->system_service, NULL, NULL,
 356                                        logptr);
 357         if (connect_rc) {
 358                 pr_err("vmlogrdr: iucv connection to %s "
 359                        "failed with rc %i \n",
 360                        logptr->system_service, connect_rc);
 361                 goto out_path;
 362         }
 363
 364         /* We've issued the connect and now we must wait for a
 365          * ConnectionComplete or ConnectinSevered Interrupt
 366          * before we can continue to process.
 367          */
 368         wait_event(conn_wait_queue, (logptr->connection_established)
 369                    || (logptr->iucv_path_severed));
 370         if (logptr->iucv_path_severed)
 371                 goto out_record;
 372         nonseekable_open(inode, filp);
 373         return 0;
 374
 375 out_record:
 376         if (logptr->autorecording)
 377                 vmlogrdr_recording(logptr,0,logptr->autopurge);
 378 out_path:
 379         kfree(logptr->path);    /* kfree(NULL) is ok. */
 380         logptr->path = NULL;
 381 out_dev:
 382         logptr->dev_in_use = 0;
 383         return -EIO;
 384 }
 385
 386
 387 static int vmlogrdr_release (struct inode *inode, struct file *filp)
 388 {
 389         int ret;
 390
 391         struct vmlogrdr_priv_t * logptr = filp->private_data;
 392
 393         iucv_path_sever(logptr->path, NULL);
 394         kfree(logptr->path);
 395         logptr->path = NULL;
 396         if (logptr->autorecording) {
 397                 ret = vmlogrdr_recording(logptr,0,logptr->autopurge);
 398                 if (ret)
 399                         pr_warn("vmlogrdr: failed to stop recording automatically\n");
 400         }
 401         logptr->dev_in_use = 0;
 402
 403         return 0;
 404 }
 405
 406
 407 static int vmlogrdr_receive_data(struct vmlogrdr_priv_t *priv)
 408 {
 409         int rc, *temp;
 410         /* we need to keep track of two data sizes here:
 411          * The number of bytes we need to receive from iucv and
 412          * the total number of bytes we actually write into the buffer.
 413          */
 414         int user_data_count, iucv_data_count;
 415         char * buffer;
 416
 417         if (atomic_read(&priv->receive_ready)) {
 418                 spin_lock_bh(&priv->priv_lock);
 419                 if (priv->residual_length){
 420                         /* receive second half of a record */
 421                         iucv_data_count = priv->residual_length;
 422                         user_data_count = 0;
 423                         buffer = priv->buffer;
 424                 } else {
 425                         /* receive a new record:
 426                          * We need to return the total length of the record
 427                          * + size of FENCE in the first 4 bytes of the buffer.
 428                          */
 429                         iucv_data_count = priv->local_interrupt_buffer.length;
 430                         user_data_count = sizeof(int);
 431                         temp = (int*)priv->buffer;
 432                         *temp= iucv_data_count + sizeof(FENCE);
 433                         buffer = priv->buffer + sizeof(int);
 434                 }
 435                 /*
 436                  * If the record is bigger than our buffer, we receive only
 437                  * a part of it. We can get the rest later.
 438                  */
 439                 if (iucv_data_count > NET_BUFFER_SIZE)
 440                         iucv_data_count = NET_BUFFER_SIZE;
 441                 rc = iucv_message_receive(priv->path,
 442                                           &priv->local_interrupt_buffer,
 443                                           0, buffer, iucv_data_count,
 444                                           &priv->residual_length);
 445                 spin_unlock_bh(&priv->priv_lock);
 446                 /* An rc of 5 indicates that the record was bigger than
 447                  * the buffer, which is OK for us. A 9 indicates that the
 448                  * record was purged befor we could receive it.
 449                  */
 450                 if (rc == 5)
 451                         rc = 0;
 452                 if (rc == 9)
 453                         atomic_set(&priv->receive_ready, 0);
 454         } else {
 455                 rc = 1;
 456         }
 457         if (!rc) {
 458                 priv->buffer_free = 0;
 459                 user_data_count += iucv_data_count;
 460                 priv->current_position = priv->buffer;
 461                 if (priv->residual_length == 0){
 462                         /* the whole record has been captured,
 463                          * now add the fence */
 464                         atomic_dec(&priv->receive_ready);
 465                         buffer = priv->buffer + user_data_count;
 466                         memcpy(buffer, FENCE, sizeof(FENCE));
 467                         user_data_count += sizeof(FENCE);
 468                 }
 469                 priv->remaining = user_data_count;
 470         }
 471
 472         return rc;
 473 }
 474
 475
 476 static ssize_t vmlogrdr_read(struct file *filp, char __user *data,
 477                              size_t count, loff_t * ppos)
 478 {
 479         int rc;
 480         struct vmlogrdr_priv_t * priv = filp->private_data;
 481
 482         while (priv->buffer_free) {
 483                 rc = vmlogrdr_receive_data(priv);
 484                 if (rc) {
 485                         rc = wait_event_interruptible(read_wait_queue,
 486                                         atomic_read(&priv->receive_ready));
 487                         if (rc)
 488                                 return rc;
 489                 }
 490         }
 491         /* copy only up to end of record */
 492         if (count > priv->remaining)
 493                 count = priv->remaining;
 494
 495         if (copy_to_user(data, priv->current_position, count))
 496                 return -EFAULT;
 497
 498         *ppos += count;
 499         priv->current_position += count;
 500         priv->remaining -= count;
 501
 502         /* if all data has been transferred, set buffer free */
 503         if (priv->remaining == 0)
 504                 priv->buffer_free = 1;
 505
 506         return count;
 507 }
 508
 509 static ssize_t vmlogrdr_autopurge_store(struct device * dev,
 510                                         struct device_attribute *attr,
 511                                         const char * buf, size_t count)
 512 {
 513         struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
 514         ssize_t ret = count;
 515
 516         switch (buf[0]) {
 517         case '0':
 518                 priv->autopurge=0;
 519                 break;
 520         case '1':
 521                 priv->autopurge=1;
 522                 break;
 523         default:
 524                 ret = -EINVAL;
 525         }
 526         return ret;
 527 }
 528
 529
 530 static ssize_t vmlogrdr_autopurge_show(struct device *dev,
 531                                        struct device_attribute *attr,
 532                                        char *buf)
 533 {
 534         struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
 535         return sprintf(buf, "%u\n", priv->autopurge);
 536 }
 537
 538
 539 static DEVICE_ATTR(autopurge, 0644, vmlogrdr_autopurge_show,
 540                    vmlogrdr_autopurge_store);
 541
 542
 543 static ssize_t vmlogrdr_purge_store(struct device * dev,
 544                                     struct device_attribute *attr,
 545                                     const char * buf, size_t count)
 546 {
 547
 548         char cp_command[80];
 549         char cp_response[80];
 550         struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
 551
 552         if (buf[0] != '1')
 553                 return -EINVAL;
 554
 555         memset(cp_command, 0x00, sizeof(cp_command));
 556         memset(cp_response, 0x00, sizeof(cp_response));
 557
 558         /*
 559          * The recording command needs to be called with option QID
 560          * for guests that have previlege classes A or B.
 561          * Other guests will not recognize the command and we have to
 562          * issue the same command without the QID parameter.
 563          */
 564
 565         if (recording_class_AB)
 566                 snprintf(cp_command, sizeof(cp_command),
 567                          "RECORDING %s PURGE QID * ",
 568                          priv->recording_name);
 569         else
 570                 snprintf(cp_command, sizeof(cp_command),
 571                          "RECORDING %s PURGE ",
 572                          priv->recording_name);
 573
 574         cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
 575
 576         return count;
 577 }
 578
 579
 580 static DEVICE_ATTR(purge, 0200, NULL, vmlogrdr_purge_store);
 581
 582
 583 static ssize_t vmlogrdr_autorecording_store(struct device *dev,
 584                                             struct device_attribute *attr,
 585                                             const char *buf, size_t count)
 586 {
 587         struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
 588         ssize_t ret = count;
 589
 590         switch (buf[0]) {
 591         case '0':
 592                 priv->autorecording=0;
 593                 break;
 594         case '1':
 595                 priv->autorecording=1;
 596                 break;
 597         default:
 598                 ret = -EINVAL;
 599         }
 600         return ret;
 601 }
 602
 603
 604 static ssize_t vmlogrdr_autorecording_show(struct device *dev,
 605                                            struct device_attribute *attr,
 606                                            char *buf)
 607 {
 608         struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
 609         return sprintf(buf, "%u\n", priv->autorecording);
 610 }
 611
 612
 613 static DEVICE_ATTR(autorecording, 0644, vmlogrdr_autorecording_show,
 614                    vmlogrdr_autorecording_store);
 615
 616
 617 static ssize_t vmlogrdr_recording_store(struct device * dev,
 618                                         struct device_attribute *attr,
 619                                         const char * buf, size_t count)
 620 {
 621         struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
 622         ssize_t ret;
 623
 624         switch (buf[0]) {
 625         case '0':
 626                 ret = vmlogrdr_recording(priv,0,0);
 627                 break;
 628         case '1':
 629                 ret = vmlogrdr_recording(priv,1,0);
 630                 break;
 631         default:
 632                 ret = -EINVAL;
 633         }
 634         if (ret)
 635                 return ret;
 636         else
 637                 return count;
 638
 639 }
 640
 641
 642 static DEVICE_ATTR(recording, 0200, NULL, vmlogrdr_recording_store);
 643
 644
 645 static ssize_t recording_status_show(struct device_driver *driver, char *buf)
 646 {
 647         static const char cp_command[] = "QUERY RECORDING ";
 648         int len;
 649
 650         cpcmd(cp_command, buf, 4096, NULL);
 651         len = strlen(buf);
 652         return len;
 653 }
 654 static DRIVER_ATTR_RO(recording_status);
 655 static struct attribute *vmlogrdr_drv_attrs[] = {
 656         &driver_attr_recording_status.attr,
 657         NULL,
 658 };
 659 static struct attribute_group vmlogrdr_drv_attr_group = {
 660         .attrs = vmlogrdr_drv_attrs,
 661 };
 662 static const struct attribute_group *vmlogrdr_drv_attr_groups[] = {
 663         &vmlogrdr_drv_attr_group,
 664         NULL,
 665 };
 666
 667 static struct attribute *vmlogrdr_attrs[] = {
 668         &dev_attr_autopurge.attr,
 669         &dev_attr_purge.attr,
 670         &dev_attr_autorecording.attr,
 671         &dev_attr_recording.attr,
 672         NULL,
 673 };
 674 static struct attribute_group vmlogrdr_attr_group = {
 675         .attrs = vmlogrdr_attrs,
 676 };
 677 static const struct attribute_group *vmlogrdr_attr_groups[] = {
 678         &vmlogrdr_attr_group,
 679         NULL,
 680 };
 681
 682 static int vmlogrdr_pm_prepare(struct device *dev)
 683 {
 684         int rc;
 685         struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
 686
 687         rc = 0;
 688         if (priv) {
 689                 spin_lock_bh(&priv->priv_lock);
 690                 if (priv->dev_in_use)
 691                         rc = -EBUSY;
 692                 spin_unlock_bh(&priv->priv_lock);
 693         }
 694         if (rc)
 695                 pr_err("vmlogrdr: device %s is busy. Refuse to suspend.\n",
 696                        dev_name(dev));
 697         return rc;
 698 }
 699
 700
 701 static const struct dev_pm_ops vmlogrdr_pm_ops = {
 702         .prepare = vmlogrdr_pm_prepare,
 703 };
 704
 705 static struct class *vmlogrdr_class;
 706 static struct device_driver vmlogrdr_driver = {
 707         .name = "vmlogrdr",
 708         .bus  = &iucv_bus,
 709         .pm = &vmlogrdr_pm_ops,
 710         .groups = vmlogrdr_drv_attr_groups,
 711 };
 712
 713 static int vmlogrdr_register_driver(void)
 714 {
 715         int ret;
 716
 717         /* Register with iucv driver */
 718         ret = iucv_register(&vmlogrdr_iucv_handler, 1);
 719         if (ret)
 720                 goto out;
 721
 722         ret = driver_register(&vmlogrdr_driver);
 723         if (ret)
 724                 goto out_iucv;
 725
 726         vmlogrdr_class = class_create(THIS_MODULE, "vmlogrdr");
 727         if (IS_ERR(vmlogrdr_class)) {
 728                 ret = PTR_ERR(vmlogrdr_class);
 729                 vmlogrdr_class = NULL;
 730                 goto out_driver;
 731         }
 732         return 0;
 733
 734 out_driver:
 735         driver_unregister(&vmlogrdr_driver);
 736 out_iucv:
 737         iucv_unregister(&vmlogrdr_iucv_handler, 1);
 738 out:
 739         return ret;
 740 }
 741
 742
 743 static void vmlogrdr_unregister_driver(void)
 744 {
 745         class_destroy(vmlogrdr_class);
 746         vmlogrdr_class = NULL;
 747         driver_unregister(&vmlogrdr_driver);
 748         iucv_unregister(&vmlogrdr_iucv_handler, 1);
 749 }
 750
 751
 752 static int vmlogrdr_register_device(struct vmlogrdr_priv_t *priv)
 753 {
 754         struct device *dev;
 755         int ret;
 756
 757         dev = kzalloc(sizeof(struct device), GFP_KERNEL);
 758         if (dev) {
 759                 dev_set_name(dev, "%s", priv->internal_name);
 760                 dev->bus = &iucv_bus;
 761                 dev->parent = iucv_root;
 762                 dev->driver = &vmlogrdr_driver;
 763                 dev->groups = vmlogrdr_attr_groups;
 764                 dev_set_drvdata(dev, priv);
 765                 /*
 766                  * The release function could be called after the
 767                  * module has been unloaded. It's _only_ task is to
 768                  * free the struct. Therefore, we specify kfree()
 769                  * directly here. (Probably a little bit obfuscating
 770                  * but legitime ...).
 771                  */
 772                 dev->release = (void (*)(struct device *))kfree;
 773         } else
 774                 return -ENOMEM;
 775         ret = device_register(dev);
 776         if (ret) {
 777                 put_device(dev);
 778                 return ret;
 779         }
 780
 781         priv->class_device = device_create(vmlogrdr_class, dev,
 782                                            MKDEV(vmlogrdr_major,
 783                                                  priv->minor_num),
 784                                            priv, "%s", dev_name(dev));
 785         if (IS_ERR(priv->class_device)) {
 786                 ret = PTR_ERR(priv->class_device);
 787                 priv->class_device=NULL;
 788                 device_unregister(dev);
 789                 return ret;
 790         }
 791         priv->device = dev;
 792         return 0;
 793 }
 794
 795
 796 static int vmlogrdr_unregister_device(struct vmlogrdr_priv_t *priv)
 797 {
 798         device_destroy(vmlogrdr_class, MKDEV(vmlogrdr_major, priv->minor_num));
 799         if (priv->device != NULL) {
 800                 device_unregister(priv->device);
 801                 priv->device=NULL;
 802         }
 803         return 0;
 804 }
 805
 806
 807 static int vmlogrdr_register_cdev(dev_t dev)
 808 {
 809         int rc = 0;
 810         vmlogrdr_cdev = cdev_alloc();
 811         if (!vmlogrdr_cdev) {
 812                 return -ENOMEM;
 813         }
 814         vmlogrdr_cdev->owner = THIS_MODULE;
 815         vmlogrdr_cdev->ops = &vmlogrdr_fops;
 816         rc = cdev_add(vmlogrdr_cdev, dev, MAXMINOR);
 817         if (!rc)
 818                 return 0;
 819
 820         // cleanup: cdev is not fully registered, no cdev_del here!
 821         kobject_put(&vmlogrdr_cdev->kobj);
 822         vmlogrdr_cdev=NULL;
 823         return rc;
 824 }
 825
 826
 827 static void vmlogrdr_cleanup(void)
 828 {
 829         int i;
 830
 831         if (vmlogrdr_cdev) {
 832                 cdev_del(vmlogrdr_cdev);
 833                 vmlogrdr_cdev=NULL;
 834         }
 835         for (i=0; i < MAXMINOR; ++i ) {
 836                 vmlogrdr_unregister_device(&sys_ser[i]);
 837                 free_page((unsigned long)sys_ser[i].buffer);
 838         }
 839         vmlogrdr_unregister_driver();
 840         if (vmlogrdr_major) {
 841                 unregister_chrdev_region(MKDEV(vmlogrdr_major, 0), MAXMINOR);
 842                 vmlogrdr_major=0;
 843         }
 844 }
 845
 846
 847 static int __init vmlogrdr_init(void)
 848 {
 849         int rc;
 850         int i;
 851         dev_t dev;
 852
 853         if (! MACHINE_IS_VM) {
 854                 pr_err("not running under VM, driver not loaded.\n");
 855                 return -ENODEV;
 856         }
 857
 858         recording_class_AB = vmlogrdr_get_recording_class_AB();
 859
 860         rc = alloc_chrdev_region(&dev, 0, MAXMINOR, "vmlogrdr");
 861         if (rc)
 862                 return rc;
 863         vmlogrdr_major = MAJOR(dev);
 864
 865         rc=vmlogrdr_register_driver();
 866         if (rc)
 867                 goto cleanup;
 868
 869         for (i=0; i < MAXMINOR; ++i ) {
 870                 sys_ser[i].buffer = (char *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
 871                 if (!sys_ser[i].buffer) {
 872                         rc = -ENOMEM;
 873                         break;
 874                 }
 875                 sys_ser[i].current_position = sys_ser[i].buffer;
 876                 rc=vmlogrdr_register_device(&sys_ser[i]);
 877                 if (rc)
 878                         break;
 879         }
 880         if (rc)
 881                 goto cleanup;
 882
 883         rc = vmlogrdr_register_cdev(dev);
 884         if (rc)
 885                 goto cleanup;
 886         return 0;
 887
 888 cleanup:
 889         vmlogrdr_cleanup();
 890         return rc;
 891 }
 892
 893
 894 static void __exit vmlogrdr_exit(void)
 895 {
 896         vmlogrdr_cleanup();
 897         return;
 898 }
 899
 900
 901 module_init(vmlogrdr_init);
 902 module_exit(vmlogrdr_exit);