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 static inline unsigned long mon_mca_start(struct mon_msg *monmsg)
 115 {
 116         return *(u32 *) &monmsg->msg.rmmsg;
 117 }
 118
 119 static inline unsigned long mon_mca_end(struct mon_msg *monmsg)
 120 {
 121         return *(u32 *) &monmsg->msg.rmmsg[4];
 122 }
 123
 124 static inline u8 mon_mca_type(struct mon_msg *monmsg, u8 index)
 125 {
 126         return *((u8 *) mon_mca_start(monmsg) + monmsg->mca_offset + index);
 127 }
 128
 129 static inline u32 mon_mca_size(struct mon_msg *monmsg)
 130 {
 131         return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1;
 132 }
 133
 134 static inline u32 mon_rec_start(struct mon_msg *monmsg)
 135 {
 136         return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 4));
 137 }
 138
 139 static inline u32 mon_rec_end(struct mon_msg *monmsg)
 140 {
 141         return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 8));
 142 }
 143
 144 static int mon_check_mca(struct mon_msg *monmsg)
 145 {
 146         if ((mon_rec_end(monmsg) <= mon_rec_start(monmsg)) ||
 147             (mon_rec_start(monmsg) < mon_dcss_start) ||
 148             (mon_rec_end(monmsg) > mon_dcss_end) ||
 149             (mon_mca_type(monmsg, 0) == 0) ||
 150             (mon_mca_size(monmsg) % 12 != 0) ||
 151             (mon_mca_end(monmsg) <= mon_mca_start(monmsg)) ||
 152             (mon_mca_end(monmsg) > mon_dcss_end) ||
 153             (mon_mca_start(monmsg) < mon_dcss_start) ||
 154             ((mon_mca_type(monmsg, 1) == 0) && (mon_mca_type(monmsg, 2) == 0)))
 155         {
 156                 P_DEBUG("READ, IGNORED INVALID MCA\n\n");
 157                 return -EINVAL;
 158         }
 159         return 0;
 160 }
 161
 162 static int mon_send_reply(struct mon_msg *monmsg,
 163                           struct mon_private *monpriv)
 164 {
 165         int rc;
 166
 167         P_DEBUG("read, REPLY: pathid = 0x%04X, msgid = 0x%08X, trgcls = "
 168                 "0x%08X\n\n",
 169                 monpriv->path->pathid, monmsg->msg.id, monmsg->msg.class);
 170
 171         rc = iucv_message_reply(monpriv->path, &monmsg->msg,
 172                                 IUCV_IPRMDATA, NULL, 0);
 173         atomic_dec(&monpriv->msglim_count);
 174         if (likely(!monmsg->msglim_reached)) {
 175                 monmsg->pos = 0;
 176                 monmsg->mca_offset = 0;
 177                 monpriv->read_index = (monpriv->read_index + 1) %
 178                                       MON_MSGLIM;
 179                 atomic_dec(&monpriv->read_ready);
 180         } else
 181                 monmsg->replied_msglim = 1;
 182         if (rc) {
 183                 P_ERROR("read, IUCV reply failed with rc = %i\n\n", rc);
 184                 return -EIO;
 185         }
 186         return 0;
 187 }
 188
 189 static void mon_free_mem(struct mon_private *monpriv)
 190 {
 191         int i;
 192
 193         for (i = 0; i < MON_MSGLIM; i++)
 194                 if (monpriv->msg_array[i])
 195                         kfree(monpriv->msg_array[i]);
 196         kfree(monpriv);
 197 }
 198
 199 static struct mon_private *mon_alloc_mem(void)
 200 {
 201         int i;
 202         struct mon_private *monpriv;
 203
 204         monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
 205         if (!monpriv) {
 206                 P_ERROR("no memory for monpriv\n");
 207                 return NULL;
 208         }
 209         for (i = 0; i < MON_MSGLIM; i++) {
 210                 monpriv->msg_array[i] = kzalloc(sizeof(struct mon_msg),
 211                                                     GFP_KERNEL);
 212                 if (!monpriv->msg_array[i]) {
 213                         P_ERROR("open, no memory for msg_array\n");
 214                         mon_free_mem(monpriv);
 215                         return NULL;
 216                 }
 217         }
 218         return monpriv;
 219 }
 220
 221 static inline void mon_read_debug(struct mon_msg *monmsg,
 222                                   struct mon_private *monpriv)
 223 {
 224 #ifdef MON_DEBUG
 225         u8 msg_type[2], mca_type;
 226         unsigned long records_len;
 227
 228         records_len = mon_rec_end(monmsg) - mon_rec_start(monmsg) + 1;
 229
 230         memcpy(msg_type, &monmsg->msg.class, 2);
 231         EBCASC(msg_type, 2);
 232         mca_type = mon_mca_type(monmsg, 0);
 233         EBCASC(&mca_type, 1);
 234
 235         P_DEBUG("read, mon_read_index = %i, mon_write_index = %i\n",
 236                 monpriv->read_index, monpriv->write_index);
 237         P_DEBUG("read, pathid = 0x%04X, msgid = 0x%08X, trgcls = 0x%08X\n",
 238                 monpriv->path->pathid, monmsg->msg.id, monmsg->msg.class);
 239         P_DEBUG("read, msg_type = '%c%c', mca_type = '%c' / 0x%X / 0x%X\n",
 240                 msg_type[0], msg_type[1], mca_type ? mca_type : 'X',
 241                 mon_mca_type(monmsg, 1), mon_mca_type(monmsg, 2));
 242         P_DEBUG("read, MCA: start = 0x%lX, end = 0x%lX\n",
 243                 mon_mca_start(monmsg), mon_mca_end(monmsg));
 244         P_DEBUG("read, REC: start = 0x%X, end = 0x%X, len = %lu\n\n",
 245                 mon_rec_start(monmsg), mon_rec_end(monmsg), records_len);
 246         if (mon_mca_size(monmsg) > 12)
 247                 P_DEBUG("READ, MORE THAN ONE MCA\n\n");
 248 #endif
 249 }
 250
 251 static inline void mon_next_mca(struct mon_msg *monmsg)
 252 {
 253         if (likely((mon_mca_size(monmsg) - monmsg->mca_offset) == 12))
 254                 return;
 255         P_DEBUG("READ, NEXT MCA\n\n");
 256         monmsg->mca_offset += 12;
 257         monmsg->pos = 0;
 258 }
 259
 260 static struct mon_msg *mon_next_message(struct mon_private *monpriv)
 261 {
 262         struct mon_msg *monmsg;
 263
 264         if (!atomic_read(&monpriv->read_ready))
 265                 return NULL;
 266         monmsg = monpriv->msg_array[monpriv->read_index];
 267         if (unlikely(monmsg->replied_msglim)) {
 268                 monmsg->replied_msglim = 0;
 269                 monmsg->msglim_reached = 0;
 270                 monmsg->pos = 0;
 271                 monmsg->mca_offset = 0;
 272                 P_WARNING("read, message limit reached\n");
 273                 monpriv->read_index = (monpriv->read_index + 1) %
 274                                       MON_MSGLIM;
 275                 atomic_dec(&monpriv->read_ready);
 276                 return ERR_PTR(-EOVERFLOW);
 277         }
 278         return monmsg;
 279 }
 280
 281
 282 /******************************************************************************
 283  *                               IUCV handler                                 *
 284  *****************************************************************************/
 285 static void mon_iucv_path_complete(struct iucv_path *path, u8 ipuser[16])
 286 {
 287         struct mon_private *monpriv = path->private;
 288
 289         P_DEBUG("IUCV connection completed\n");
 290         P_DEBUG("IUCV ACCEPT (from *MONITOR): Version = 0x%02X, Event = "
 291                 "0x%02X, Sample = 0x%02X\n",
 292                 ipuser[0], ipuser[1], ipuser[2]);
 293         atomic_set(&monpriv->iucv_connected, 1);
 294         wake_up(&mon_conn_wait_queue);
 295 }
 296
 297 static void mon_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
 298 {
 299         struct mon_private *monpriv = path->private;
 300
 301         P_ERROR("IUCV connection severed with rc = 0x%X\n", ipuser[0]);
 302         iucv_path_sever(path, NULL);
 303         atomic_set(&monpriv->iucv_severed, 1);
 304         wake_up(&mon_conn_wait_queue);
 305         wake_up_interruptible(&mon_read_wait_queue);
 306 }
 307
 308 static void mon_iucv_message_pending(struct iucv_path *path,
 309                                      struct iucv_message *msg)
 310 {
 311         struct mon_private *monpriv = path->private;
 312
 313         P_DEBUG("IUCV message pending\n");
 314         memcpy(&monpriv->msg_array[monpriv->write_index]->msg,
 315                msg, sizeof(*msg));
 316         if (atomic_inc_return(&monpriv->msglim_count) == MON_MSGLIM) {
 317                 P_WARNING("IUCV message pending, message limit (%i) reached\n",
 318                           MON_MSGLIM);
 319                 monpriv->msg_array[monpriv->write_index]->msglim_reached = 1;
 320         }
 321         monpriv->write_index = (monpriv->write_index + 1) % MON_MSGLIM;
 322         atomic_inc(&monpriv->read_ready);
 323         wake_up_interruptible(&mon_read_wait_queue);
 324 }
 325
 326 static struct iucv_handler monreader_iucv_handler = {
 327         .path_complete   = mon_iucv_path_complete,
 328         .path_severed    = mon_iucv_path_severed,
 329         .message_pending = mon_iucv_message_pending,
 330 };
 331
 332 /******************************************************************************
 333  *                               file operations                              *
 334  *****************************************************************************/
 335 static int mon_open(struct inode *inode, struct file *filp)
 336 {
 337         struct mon_private *monpriv;
 338         int rc;
 339
 340         /*
 341          * only one user allowed
 342          */
 343         rc = -EBUSY;
 344         if (test_and_set_bit(MON_IN_USE, &mon_in_use))
 345                 goto out;
 346
 347         rc = -ENOMEM;
 348         monpriv = mon_alloc_mem();
 349         if (!monpriv)
 350                 goto out_use;
 351
 352         /*
 353          * Connect to *MONITOR service
 354          */
 355         monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
 356         if (!monpriv->path)
 357                 goto out_priv;
 358         rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
 359                                MON_SERVICE, NULL, user_data_connect, monpriv);
 360         if (rc) {
 361                 P_ERROR("iucv connection to *MONITOR failed with "
 362                         "IPUSER SEVER code = %i\n", rc);
 363                 rc = -EIO;
 364                 goto out_path;
 365         }
 366         /*
 367          * Wait for connection confirmation
 368          */
 369         wait_event(mon_conn_wait_queue,
 370                    atomic_read(&monpriv->iucv_connected) ||
 371                    atomic_read(&monpriv->iucv_severed));
 372         if (atomic_read(&monpriv->iucv_severed)) {
 373                 atomic_set(&monpriv->iucv_severed, 0);
 374                 atomic_set(&monpriv->iucv_connected, 0);
 375                 rc = -EIO;
 376                 goto out_path;
 377         }
 378         P_INFO("open, established connection to *MONITOR service\n\n");
 379         filp->private_data = monpriv;
 380         return nonseekable_open(inode, filp);
 381
 382 out_path:
 383         kfree(monpriv->path);
 384 out_priv:
 385         mon_free_mem(monpriv);
 386 out_use:
 387         clear_bit(MON_IN_USE, &mon_in_use);
 388 out:
 389         return rc;
 390 }
 391
 392 static int mon_close(struct inode *inode, struct file *filp)
 393 {
 394         int rc, i;
 395         struct mon_private *monpriv = filp->private_data;
 396
 397         /*
 398          * Close IUCV connection and unregister
 399          */
 400         rc = iucv_path_sever(monpriv->path, user_data_sever);
 401         if (rc)
 402                 P_ERROR("close, iucv_sever failed with rc = %i\n", rc);
 403         else
 404                 P_INFO("close, terminated connection to *MONITOR service\n");
 405
 406         atomic_set(&monpriv->iucv_severed, 0);
 407         atomic_set(&monpriv->iucv_connected, 0);
 408         atomic_set(&monpriv->read_ready, 0);
 409         atomic_set(&monpriv->msglim_count, 0);
 410         monpriv->write_index  = 0;
 411         monpriv->read_index   = 0;
 412
 413         for (i = 0; i < MON_MSGLIM; i++)
 414                 kfree(monpriv->msg_array[i]);
 415         kfree(monpriv);
 416         clear_bit(MON_IN_USE, &mon_in_use);
 417         return 0;
 418 }
 419
 420 static ssize_t mon_read(struct file *filp, char __user *data,
 421                         size_t count, loff_t *ppos)
 422 {
 423         struct mon_private *monpriv = filp->private_data;
 424         struct mon_msg *monmsg;
 425         int ret;
 426         u32 mce_start;
 427
 428         monmsg = mon_next_message(monpriv);
 429         if (IS_ERR(monmsg))
 430                 return PTR_ERR(monmsg);
 431
 432         if (!monmsg) {
 433                 if (filp->f_flags & O_NONBLOCK)
 434                         return -EAGAIN;
 435                 ret = wait_event_interruptible(mon_read_wait_queue,
 436                                         atomic_read(&monpriv->read_ready) ||
 437                                         atomic_read(&monpriv->iucv_severed));
 438                 if (ret)
 439                         return ret;
 440                 if (unlikely(atomic_read(&monpriv->iucv_severed)))
 441                         return -EIO;
 442                 monmsg = monpriv->msg_array[monpriv->read_index];
 443         }
 444
 445         if (!monmsg->pos) {
 446                 monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset;
 447                 mon_read_debug(monmsg, monpriv);
 448         }
 449         if (mon_check_mca(monmsg))
 450                 goto reply;
 451
 452         /* read monitor control element (12 bytes) first */
 453         mce_start = mon_mca_start(monmsg) + monmsg->mca_offset;
 454         if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) {
 455                 count = min(count, (size_t) mce_start + 12 - monmsg->pos);
 456                 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
 457                                    count);
 458                 if (ret)
 459                         return -EFAULT;
 460                 monmsg->pos += count;
 461                 if (monmsg->pos == mce_start + 12)
 462                         monmsg->pos = mon_rec_start(monmsg);
 463                 goto out_copy;
 464         }
 465
 466         /* read records */
 467         if (monmsg->pos <= mon_rec_end(monmsg)) {
 468                 count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos
 469                                             + 1);
 470                 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
 471                                    count);
 472                 if (ret)
 473                         return -EFAULT;
 474                 monmsg->pos += count;
 475                 if (monmsg->pos > mon_rec_end(monmsg))
 476                         mon_next_mca(monmsg);
 477                 goto out_copy;
 478         }
 479 reply:
 480         ret = mon_send_reply(monmsg, monpriv);
 481         return ret;
 482
 483 out_copy:
 484         *ppos += count;
 485         return count;
 486 }
 487
 488 static unsigned int mon_poll(struct file *filp, struct poll_table_struct *p)
 489 {
 490         struct mon_private *monpriv = filp->private_data;
 491
 492         poll_wait(filp, &mon_read_wait_queue, p);
 493         if (unlikely(atomic_read(&monpriv->iucv_severed)))
 494                 return POLLERR;
 495         if (atomic_read(&monpriv->read_ready))
 496                 return POLLIN | POLLRDNORM;
 497         return 0;
 498 }
 499
 500 static const struct file_operations mon_fops = {
 501         .owner   = THIS_MODULE,
 502         .open    = &mon_open,
 503         .release = &mon_close,
 504         .read    = &mon_read,
 505         .poll    = &mon_poll,
 506 };
 507
 508 static struct miscdevice mon_dev = {
 509         .name       = "monreader",
 510         .fops       = &mon_fops,
 511         .minor      = MISC_DYNAMIC_MINOR,
 512 };
 513
 514 /******************************************************************************
 515  *                              module init/exit                              *
 516  *****************************************************************************/
 517 static int __init mon_init(void)
 518 {
 519         int rc;
 520
 521         if (!MACHINE_IS_VM) {
 522                 P_ERROR("not running under z/VM, driver not loaded\n");
 523                 return -ENODEV;
 524         }
 525
 526         /*
 527          * Register with IUCV and connect to *MONITOR service
 528          */
 529         rc = iucv_register(&monreader_iucv_handler, 1);
 530         if (rc) {
 531                 P_ERROR("failed to register with iucv driver\n");
 532                 return rc;
 533         }
 534         P_INFO("open, registered with IUCV\n");
 535
 536         rc = segment_type(mon_dcss_name);
 537         if (rc < 0) {
 538                 segment_warning(rc, mon_dcss_name);
 539                 goto out_iucv;
 540         }
 541         if (rc != SEG_TYPE_SC) {
 542                 P_ERROR("segment %s has unsupported type, should be SC\n",
 543                         mon_dcss_name);
 544                 rc = -EINVAL;
 545                 goto out_iucv;
 546         }
 547
 548         rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
 549                           &mon_dcss_start, &mon_dcss_end);
 550         if (rc < 0) {
 551                 segment_warning(rc, mon_dcss_name);
 552                 rc = -EINVAL;
 553                 goto out_iucv;
 554         }
 555         dcss_mkname(mon_dcss_name, &user_data_connect[8]);
 556
 557         rc = misc_register(&mon_dev);
 558         if (rc < 0 ) {
 559                 P_ERROR("misc_register failed, rc = %i\n", rc);
 560                 goto out;
 561         }
 562         P_INFO("Loaded segment %s from %p to %p, size = %lu Byte\n",
 563                 mon_dcss_name, (void *) mon_dcss_start, (void *) mon_dcss_end,
 564                 mon_dcss_end - mon_dcss_start + 1);
 565         return 0;
 566
 567 out:
 568         segment_unload(mon_dcss_name);
 569 out_iucv:
 570         iucv_unregister(&monreader_iucv_handler, 1);
 571         return rc;
 572 }
 573
 574 static void __exit mon_exit(void)
 575 {
 576         segment_unload(mon_dcss_name);
 577         WARN_ON(misc_deregister(&mon_dev) != 0);
 578         iucv_unregister(&monreader_iucv_handler, 1);
 579         return;
 580 }
 581
 582
 583 module_init(mon_init);
 584 module_exit(mon_exit);
 585
 586 module_param_string(mondcss, mon_dcss_name, 9, 0444);
 587 MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR "
 588                  "service, max. 8 chars. Default is MONDCSS");
 589
 590 MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>");
 591 MODULE_DESCRIPTION("Character device driver for reading z/VM "
 592                    "monitor service records.");
 593 MODULE_LICENSE("GPL");