drivers/char/hvc_iucv.c

   1 /*
   2  * hvc_iucv.c - z/VM IUCV hypervisor console (HVC) device driver
   3  *
   4  * This HVC device driver provides terminal access using
   5  * z/VM IUCV communication paths.
   6  *
   7  * Copyright IBM Corp. 2008, 2009
   8  *
   9  * Author(s):   Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
  10  */
  11 #define KMSG_COMPONENT          "hvc_iucv"
  12 #define pr_fmt(fmt)             KMSG_COMPONENT ": " fmt
  13
  14 #include <linux/types.h>
  15 #include <linux/slab.h>
  16 #include <asm/ebcdic.h>
  17 #include <linux/ctype.h>
  18 #include <linux/delay.h>
  19 #include <linux/device.h>
  20 #include <linux/init.h>
  21 #include <linux/mempool.h>
  22 #include <linux/moduleparam.h>
  23 #include <linux/tty.h>
  24 #include <linux/wait.h>
  25 #include <net/iucv/iucv.h>
  26
  27 #include "hvc_console.h"
  28
  29
  30 /* General device driver settings */
  31 #define HVC_IUCV_MAGIC          0xc9e4c3e5
  32 #define MAX_HVC_IUCV_LINES      HVC_ALLOC_TTY_ADAPTERS
  33 #define MEMPOOL_MIN_NR          (PAGE_SIZE / sizeof(struct iucv_tty_buffer)/4)
  34
  35 /* IUCV TTY message  */
  36 #define MSG_VERSION             0x02    /* Message version */
  37 #define MSG_TYPE_ERROR          0x01    /* Error message */
  38 #define MSG_TYPE_TERMENV        0x02    /* Terminal environment variable */
  39 #define MSG_TYPE_TERMIOS        0x04    /* Terminal IO struct update */
  40 #define MSG_TYPE_WINSIZE        0x08    /* Terminal window size update */
  41 #define MSG_TYPE_DATA           0x10    /* Terminal data */
  42
  43 struct iucv_tty_msg {
  44         u8      version;                /* Message version */
  45         u8      type;                   /* Message type */
  46 #define MSG_MAX_DATALEN         ((u16)(~0))
  47         u16     datalen;                /* Payload length */
  48         u8      data[];                 /* Payload buffer */
  49 } __attribute__((packed));
  50 #define MSG_SIZE(s)             ((s) + offsetof(struct iucv_tty_msg, data))
  51
  52 enum iucv_state_t {
  53         IUCV_DISCONN    = 0,
  54         IUCV_CONNECTED  = 1,
  55         IUCV_SEVERED    = 2,
  56 };
  57
  58 enum tty_state_t {
  59         TTY_CLOSED      = 0,
  60         TTY_OPENED      = 1,
  61 };
  62
  63 struct hvc_iucv_private {
  64         struct hvc_struct       *hvc;           /* HVC struct reference */
  65         u8                      srv_name[8];    /* IUCV service name (ebcdic) */
  66         unsigned char           is_console;     /* Linux console usage flag */
  67         enum iucv_state_t       iucv_state;     /* IUCV connection status */
  68         enum tty_state_t        tty_state;      /* TTY status */
  69         struct iucv_path        *path;          /* IUCV path pointer */
  70         spinlock_t              lock;           /* hvc_iucv_private lock */
  71 #define SNDBUF_SIZE             (PAGE_SIZE)     /* must be < MSG_MAX_DATALEN */
  72         void                    *sndbuf;        /* send buffer            */
  73         size_t                  sndbuf_len;     /* length of send buffer  */
  74 #define QUEUE_SNDBUF_DELAY      (HZ / 25)
  75         struct delayed_work     sndbuf_work;    /* work: send iucv msg(s) */
  76         wait_queue_head_t       sndbuf_waitq;   /* wait for send completion */
  77         struct list_head        tty_outqueue;   /* outgoing IUCV messages */
  78         struct list_head        tty_inqueue;    /* incoming IUCV messages */
  79         struct device           *dev;           /* device structure */
  80 };
  81
  82 struct iucv_tty_buffer {
  83         struct list_head        list;   /* list pointer */
  84         struct iucv_message     msg;    /* store an IUCV message */
  85         size_t                  offset; /* data buffer offset */
  86         struct iucv_tty_msg     *mbuf;  /* buffer to store input/output data */
  87 };
  88
  89 /* IUCV callback handler */
  90 static  int hvc_iucv_path_pending(struct iucv_path *, u8[8], u8[16]);
  91 static void hvc_iucv_path_severed(struct iucv_path *, u8[16]);
  92 static void hvc_iucv_msg_pending(struct iucv_path *, struct iucv_message *);
  93 static void hvc_iucv_msg_complete(struct iucv_path *, struct iucv_message *);
  94
  95
  96 /* Kernel module parameter: use one terminal device as default */
  97 static unsigned long hvc_iucv_devices = 1;
  98
  99 /* Array of allocated hvc iucv tty lines... */
 100 static struct hvc_iucv_private *hvc_iucv_table[MAX_HVC_IUCV_LINES];
 101 #define IUCV_HVC_CON_IDX        (0)
 102 /* List of z/VM user ID filter entries (struct iucv_vmid_filter) */
 103 #define MAX_VMID_FILTER         (500)
 104 static size_t hvc_iucv_filter_size;
 105 static void *hvc_iucv_filter;
 106 static const char *hvc_iucv_filter_string;
 107 static DEFINE_RWLOCK(hvc_iucv_filter_lock);
 108
 109 /* Kmem cache and mempool for iucv_tty_buffer elements */
 110 static struct kmem_cache *hvc_iucv_buffer_cache;
 111 static mempool_t *hvc_iucv_mempool;
 112
 113 /* IUCV handler callback functions */
 114 static struct iucv_handler hvc_iucv_handler = {
 115         .path_pending  = hvc_iucv_path_pending,
 116         .path_severed  = hvc_iucv_path_severed,
 117         .message_complete = hvc_iucv_msg_complete,
 118         .message_pending  = hvc_iucv_msg_pending,
 119 };
 120
 121
 122 /**
 123  * hvc_iucv_get_private() - Return a struct hvc_iucv_private instance.
 124  * @num:        The HVC virtual terminal number (vtermno)
 125  *
 126  * This function returns the struct hvc_iucv_private instance that corresponds
 127  * to the HVC virtual terminal number specified as parameter @num.
 128  */
 129 struct hvc_iucv_private *hvc_iucv_get_private(uint32_t num)
 130 {
 131         if ((num < HVC_IUCV_MAGIC) || (num - HVC_IUCV_MAGIC > hvc_iucv_devices))
 132                 return NULL;
 133         return hvc_iucv_table[num - HVC_IUCV_MAGIC];
 134 }
 135
 136 /**
 137  * alloc_tty_buffer() - Return a new struct iucv_tty_buffer element.
 138  * @size:       Size of the internal buffer used to store data.
 139  * @flags:      Memory allocation flags passed to mempool.
 140  *
 141  * This function allocates a new struct iucv_tty_buffer element and, optionally,
 142  * allocates an internal data buffer with the specified size @size.
 143  * The internal data buffer is always allocated with GFP_DMA which is
 144  * required for receiving and sending data with IUCV.
 145  * Note: The total message size arises from the internal buffer size and the
 146  *       members of the iucv_tty_msg structure.
 147  * The function returns NULL if memory allocation has failed.
 148  */
 149 static struct iucv_tty_buffer *alloc_tty_buffer(size_t size, gfp_t flags)
 150 {
 151         struct iucv_tty_buffer *bufp;
 152
 153         bufp = mempool_alloc(hvc_iucv_mempool, flags);
 154         if (!bufp)
 155                 return NULL;
 156         memset(bufp, 0, sizeof(*bufp));
 157
 158         if (size > 0) {
 159                 bufp->msg.length = MSG_SIZE(size);
 160                 bufp->mbuf = kmalloc(bufp->msg.length, flags | GFP_DMA);
 161                 if (!bufp->mbuf) {
 162                         mempool_free(bufp, hvc_iucv_mempool);
 163                         return NULL;
 164                 }
 165                 bufp->mbuf->version = MSG_VERSION;
 166                 bufp->mbuf->type    = MSG_TYPE_DATA;
 167                 bufp->mbuf->datalen = (u16) size;
 168         }
 169         return bufp;
 170 }
 171
 172 /**
 173  * destroy_tty_buffer() - destroy struct iucv_tty_buffer element.
 174  * @bufp:       Pointer to a struct iucv_tty_buffer element, SHALL NOT be NULL.
 175  */
 176 static void destroy_tty_buffer(struct iucv_tty_buffer *bufp)
 177 {
 178         kfree(bufp->mbuf);
 179         mempool_free(bufp, hvc_iucv_mempool);
 180 }
 181
 182 /**
 183  * destroy_tty_buffer_list() - call destroy_tty_buffer() for each list element.
 184  * @list:       List containing struct iucv_tty_buffer elements.
 185  */
 186 static void destroy_tty_buffer_list(struct list_head *list)
 187 {
 188         struct iucv_tty_buffer *ent, *next;
 189
 190         list_for_each_entry_safe(ent, next, list, list) {
 191                 list_del(&ent->list);
 192                 destroy_tty_buffer(ent);
 193         }
 194 }
 195
 196 /**
 197  * hvc_iucv_write() - Receive IUCV message & write data to HVC buffer.
 198  * @priv:               Pointer to struct hvc_iucv_private
 199  * @buf:                HVC buffer for writing received terminal data.
 200  * @count:              HVC buffer size.
 201  * @has_more_data:      Pointer to an int variable.
 202  *
 203  * The function picks up pending messages from the input queue and receives
 204  * the message data that is then written to the specified buffer @buf.
 205  * If the buffer size @count is less than the data message size, the
 206  * message is kept on the input queue and @has_more_data is set to 1.
 207  * If all message data has been written, the message is removed from
 208  * the input queue.
 209  *
 210  * The function returns the number of bytes written to the terminal, zero if
 211  * there are no pending data messages available or if there is no established
 212  * IUCV path.
 213  * If the IUCV path has been severed, then -EPIPE is returned to cause a
 214  * hang up (that is issued by the HVC layer).
 215  */
 216 static int hvc_iucv_write(struct hvc_iucv_private *priv,
 217                           char *buf, int count, int *has_more_data)
 218 {
 219         struct iucv_tty_buffer *rb;
 220         int written;
 221         int rc;
 222
 223         /* immediately return if there is no IUCV connection */
 224         if (priv->iucv_state == IUCV_DISCONN)
 225                 return 0;
 226
 227         /* if the IUCV path has been severed, return -EPIPE to inform the
 228          * HVC layer to hang up the tty device. */
 229         if (priv->iucv_state == IUCV_SEVERED)
 230                 return -EPIPE;
 231
 232         /* check if there are pending messages */
 233         if (list_empty(&priv->tty_inqueue))
 234                 return 0;
 235
 236         /* receive an iucv message and flip data to the tty (ldisc) */
 237         rb = list_first_entry(&priv->tty_inqueue, struct iucv_tty_buffer, list);
 238
 239         written = 0;
 240         if (!rb->mbuf) { /* message not yet received ... */
 241                 /* allocate mem to store msg data; if no memory is available
 242                  * then leave the buffer on the list and re-try later */
 243                 rb->mbuf = kmalloc(rb->msg.length, GFP_ATOMIC | GFP_DMA);
 244                 if (!rb->mbuf)
 245                         return -ENOMEM;
 246
 247                 rc = __iucv_message_receive(priv->path, &rb->msg, 0,
 248                                             rb->mbuf, rb->msg.length, NULL);
 249                 switch (rc) {
 250                 case 0: /* Successful       */
 251                         break;
 252                 case 2: /* No message found */
 253                 case 9: /* Message purged   */
 254                         break;
 255                 default:
 256                         written = -EIO;
 257                 }
 258                 /* remove buffer if an error has occured or received data
 259                  * is not correct */
 260                 if (rc || (rb->mbuf->version != MSG_VERSION) ||
 261                           (rb->msg.length    != MSG_SIZE(rb->mbuf->datalen)))
 262                         goto out_remove_buffer;
 263         }
 264
 265         switch (rb->mbuf->type) {
 266         case MSG_TYPE_DATA:
 267                 written = min_t(int, rb->mbuf->datalen - rb->offset, count);
 268                 memcpy(buf, rb->mbuf->data + rb->offset, written);
 269                 if (written < (rb->mbuf->datalen - rb->offset)) {
 270                         rb->offset += written;
 271                         *has_more_data = 1;
 272                         goto out_written;
 273                 }
 274                 break;
 275
 276         case MSG_TYPE_WINSIZE:
 277                 if (rb->mbuf->datalen != sizeof(struct winsize))
 278                         break;
 279                 /* The caller must ensure that the hvc is locked, which
 280                  * is the case when called from hvc_iucv_get_chars() */
 281                 __hvc_resize(priv->hvc, *((struct winsize *) rb->mbuf->data));
 282                 break;
 283
 284         case MSG_TYPE_ERROR:    /* ignored ... */
 285         case MSG_TYPE_TERMENV:  /* ignored ... */
 286         case MSG_TYPE_TERMIOS:  /* ignored ... */
 287                 break;
 288         }
 289
 290 out_remove_buffer:
 291         list_del(&rb->list);
 292         destroy_tty_buffer(rb);
 293         *has_more_data = !list_empty(&priv->tty_inqueue);
 294
 295 out_written:
 296         return written;
 297 }
 298
 299 /**
 300  * hvc_iucv_get_chars() - HVC get_chars operation.
 301  * @vtermno:    HVC virtual terminal number.
 302  * @buf:        Pointer to a buffer to store data
 303  * @count:      Size of buffer available for writing
 304  *
 305  * The HVC thread calls this method to read characters from the back-end.
 306  * If an IUCV communication path has been established, pending IUCV messages
 307  * are received and data is copied into buffer @buf up to @count bytes.
 308  *
 309  * Locking:     The routine gets called under an irqsave() spinlock; and
 310  *              the routine locks the struct hvc_iucv_private->lock to call
 311  *              helper functions.
 312  */
 313 static int hvc_iucv_get_chars(uint32_t vtermno, char *buf, int count)
 314 {
 315         struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 316         int written;
 317         int has_more_data;
 318
 319         if (count <= 0)
 320                 return 0;
 321
 322         if (!priv)
 323                 return -ENODEV;
 324
 325         spin_lock(&priv->lock);
 326         has_more_data = 0;
 327         written = hvc_iucv_write(priv, buf, count, &has_more_data);
 328         spin_unlock(&priv->lock);
 329
 330         /* if there are still messages on the queue... schedule another run */
 331         if (has_more_data)
 332                 hvc_kick();
 333
 334         return written;
 335 }
 336
 337 /**
 338  * hvc_iucv_queue() - Buffer terminal data for sending.
 339  * @priv:       Pointer to struct hvc_iucv_private instance.
 340  * @buf:        Buffer containing data to send.
 341  * @count:      Size of buffer and amount of data to send.
 342  *
 343  * The function queues data for sending. To actually send the buffered data,
 344  * a work queue function is scheduled (with QUEUE_SNDBUF_DELAY).
 345  * The function returns the number of data bytes that has been buffered.
 346  *
 347  * If the device is not connected, data is ignored and the function returns
 348  * @count.
 349  * If the buffer is full, the function returns 0.
 350  * If an existing IUCV communicaton path has been severed, -EPIPE is returned
 351  * (that can be passed to HVC layer to cause a tty hangup).
 352  */
 353 static int hvc_iucv_queue(struct hvc_iucv_private *priv, const char *buf,
 354                           int count)
 355 {
 356         size_t len;
 357
 358         if (priv->iucv_state == IUCV_DISCONN)
 359                 return count;                   /* ignore data */
 360
 361         if (priv->iucv_state == IUCV_SEVERED)
 362                 return -EPIPE;
 363
 364         len = min_t(size_t, count, SNDBUF_SIZE - priv->sndbuf_len);
 365         if (!len)
 366                 return 0;
 367
 368         memcpy(priv->sndbuf + priv->sndbuf_len, buf, len);
 369         priv->sndbuf_len += len;
 370
 371         if (priv->iucv_state == IUCV_CONNECTED)
 372                 schedule_delayed_work(&priv->sndbuf_work, QUEUE_SNDBUF_DELAY);
 373
 374         return len;
 375 }
 376
 377 /**
 378  * hvc_iucv_send() - Send an IUCV message containing terminal data.
 379  * @priv:       Pointer to struct hvc_iucv_private instance.
 380  *
 381  * If an IUCV communication path has been established, the buffered output data
 382  * is sent via an IUCV message and the number of bytes sent is returned.
 383  * Returns 0 if there is no established IUCV communication path or
 384  * -EPIPE if an existing IUCV communicaton path has been severed.
 385  */
 386 static int hvc_iucv_send(struct hvc_iucv_private *priv)
 387 {
 388         struct iucv_tty_buffer *sb;
 389         int rc, len;
 390
 391         if (priv->iucv_state == IUCV_SEVERED)
 392                 return -EPIPE;
 393
 394         if (priv->iucv_state == IUCV_DISCONN)
 395                 return -EIO;
 396
 397         if (!priv->sndbuf_len)
 398                 return 0;
 399
 400         /* allocate internal buffer to store msg data and also compute total
 401          * message length */
 402         sb = alloc_tty_buffer(priv->sndbuf_len, GFP_ATOMIC);
 403         if (!sb)
 404                 return -ENOMEM;
 405
 406         memcpy(sb->mbuf->data, priv->sndbuf, priv->sndbuf_len);
 407         sb->mbuf->datalen = (u16) priv->sndbuf_len;
 408         sb->msg.length = MSG_SIZE(sb->mbuf->datalen);
 409
 410         list_add_tail(&sb->list, &priv->tty_outqueue);
 411
 412         rc = __iucv_message_send(priv->path, &sb->msg, 0, 0,
 413                                  (void *) sb->mbuf, sb->msg.length);
 414         if (rc) {
 415                 /* drop the message here; however we might want to handle
 416                  * 0x03 (msg limit reached) by trying again... */
 417                 list_del(&sb->list);
 418                 destroy_tty_buffer(sb);
 419         }
 420         len = priv->sndbuf_len;
 421         priv->sndbuf_len = 0;
 422
 423         return len;
 424 }
 425
 426 /**
 427  * hvc_iucv_sndbuf_work() - Send buffered data over IUCV
 428  * @work:       Work structure.
 429  *
 430  * This work queue function sends buffered output data over IUCV and,
 431  * if not all buffered data could be sent, reschedules itself.
 432  */
 433 static void hvc_iucv_sndbuf_work(struct work_struct *work)
 434 {
 435         struct hvc_iucv_private *priv;
 436
 437         priv = container_of(work, struct hvc_iucv_private, sndbuf_work.work);
 438         if (!priv)
 439                 return;
 440
 441         spin_lock_bh(&priv->lock);
 442         hvc_iucv_send(priv);
 443         spin_unlock_bh(&priv->lock);
 444 }
 445
 446 /**
 447  * hvc_iucv_put_chars() - HVC put_chars operation.
 448  * @vtermno:    HVC virtual terminal number.
 449  * @buf:        Pointer to an buffer to read data from
 450  * @count:      Size of buffer available for reading
 451  *
 452  * The HVC thread calls this method to write characters to the back-end.
 453  * The function calls hvc_iucv_queue() to queue terminal data for sending.
 454  *
 455  * Locking:     The method gets called under an irqsave() spinlock; and
 456  *              locks struct hvc_iucv_private->lock.
 457  */
 458 static int hvc_iucv_put_chars(uint32_t vtermno, const char *buf, int count)
 459 {
 460         struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 461         int queued;
 462
 463         if (count <= 0)
 464                 return 0;
 465
 466         if (!priv)
 467                 return -ENODEV;
 468
 469         spin_lock(&priv->lock);
 470         queued = hvc_iucv_queue(priv, buf, count);
 471         spin_unlock(&priv->lock);
 472
 473         return queued;
 474 }
 475
 476 /**
 477  * hvc_iucv_notifier_add() - HVC notifier for opening a TTY for the first time.
 478  * @hp: Pointer to the HVC device (struct hvc_struct)
 479  * @id: Additional data (originally passed to hvc_alloc): the index of an struct
 480  *      hvc_iucv_private instance.
 481  *
 482  * The function sets the tty state to TTY_OPENED for the struct hvc_iucv_private
 483  * instance that is derived from @id. Always returns 0.
 484  *
 485  * Locking:     struct hvc_iucv_private->lock, spin_lock_bh
 486  */
 487 static int hvc_iucv_notifier_add(struct hvc_struct *hp, int id)
 488 {
 489         struct hvc_iucv_private *priv;
 490
 491         priv = hvc_iucv_get_private(id);
 492         if (!priv)
 493                 return 0;
 494
 495         spin_lock_bh(&priv->lock);
 496         priv->tty_state = TTY_OPENED;
 497         spin_unlock_bh(&priv->lock);
 498
 499         return 0;
 500 }
 501
 502 /**
 503  * hvc_iucv_cleanup() - Clean up and reset a z/VM IUCV HVC instance.
 504  * @priv:       Pointer to the struct hvc_iucv_private instance.
 505  */
 506 static void hvc_iucv_cleanup(struct hvc_iucv_private *priv)
 507 {
 508         destroy_tty_buffer_list(&priv->tty_outqueue);
 509         destroy_tty_buffer_list(&priv->tty_inqueue);
 510
 511         priv->tty_state = TTY_CLOSED;
 512         priv->iucv_state = IUCV_DISCONN;
 513
 514         priv->sndbuf_len = 0;
 515 }
 516
 517 /**
 518  * tty_outqueue_empty() - Test if the tty outq is empty
 519  * @priv:       Pointer to struct hvc_iucv_private instance.
 520  */
 521 static inline int tty_outqueue_empty(struct hvc_iucv_private *priv)
 522 {
 523         int rc;
 524
 525         spin_lock_bh(&priv->lock);
 526         rc = list_empty(&priv->tty_outqueue);
 527         spin_unlock_bh(&priv->lock);
 528
 529         return rc;
 530 }
 531
 532 /**
 533  * flush_sndbuf_sync() - Flush send buffer and wait for completion
 534  * @priv:       Pointer to struct hvc_iucv_private instance.
 535  *
 536  * The routine cancels a pending sndbuf work, calls hvc_iucv_send()
 537  * to flush any buffered terminal output data and waits for completion.
 538  */
 539 static void flush_sndbuf_sync(struct hvc_iucv_private *priv)
 540 {
 541         int sync_wait;
 542
 543         cancel_delayed_work_sync(&priv->sndbuf_work);
 544
 545         spin_lock_bh(&priv->lock);
 546         hvc_iucv_send(priv);            /* force sending buffered data */
 547         sync_wait = !list_empty(&priv->tty_outqueue); /* anything queued ? */
 548         spin_unlock_bh(&priv->lock);
 549
 550         if (sync_wait)
 551                 wait_event_timeout(priv->sndbuf_waitq,
 552                                    tty_outqueue_empty(priv), HZ/10);
 553 }
 554
 555 /**
 556  * hvc_iucv_hangup() - Sever IUCV path and schedule hvc tty hang up
 557  * @priv:       Pointer to hvc_iucv_private structure
 558  *
 559  * This routine severs an existing IUCV communication path and hangs
 560  * up the underlying HVC terminal device.
 561  * The hang-up occurs only if an IUCV communication path is established;
 562  * otherwise there is no need to hang up the terminal device.
 563  *
 564  * The IUCV HVC hang-up is separated into two steps:
 565  * 1. After the IUCV path has been severed, the iucv_state is set to
 566  *    IUCV_SEVERED.
 567  * 2. Later, when the HVC thread calls hvc_iucv_get_chars(), the
 568  *    IUCV_SEVERED state causes the tty hang-up in the HVC layer.
 569  *
 570  * If the tty has not yet been opened, clean up the hvc_iucv_private
 571  * structure to allow re-connects.
 572  * If the tty has been opened, let get_chars() return -EPIPE to signal
 573  * the HVC layer to hang up the tty and, if so, wake up the HVC thread
 574  * to call get_chars()...
 575  *
 576  * Special notes on hanging up a HVC terminal instantiated as console:
 577  * Hang-up:     1. do_tty_hangup() replaces file ops (= hung_up_tty_fops)
 578  *              2. do_tty_hangup() calls tty->ops->close() for console_filp
 579  *                      => no hangup notifier is called by HVC (default)
 580  *              2. hvc_close() returns because of tty_hung_up_p(filp)
 581  *                      => no delete notifier is called!
 582  * Finally, the back-end is not being notified, thus, the tty session is
 583  * kept active (TTY_OPEN) to be ready for re-connects.
 584  *
 585  * Locking:     spin_lock(&priv->lock) w/o disabling bh
 586  */
 587 static void hvc_iucv_hangup(struct hvc_iucv_private *priv)
 588 {
 589         struct iucv_path *path;
 590
 591         path = NULL;
 592         spin_lock(&priv->lock);
 593         if (priv->iucv_state == IUCV_CONNECTED) {
 594                 path = priv->path;
 595                 priv->path = NULL;
 596                 priv->iucv_state = IUCV_SEVERED;
 597                 if (priv->tty_state == TTY_CLOSED)
 598                         hvc_iucv_cleanup(priv);
 599                 else
 600                         /* console is special (see above) */
 601                         if (priv->is_console) {
 602                                 hvc_iucv_cleanup(priv);
 603                                 priv->tty_state = TTY_OPENED;
 604                         } else
 605                                 hvc_kick();
 606         }
 607         spin_unlock(&priv->lock);
 608
 609         /* finally sever path (outside of priv->lock due to lock ordering) */
 610         if (path) {
 611                 iucv_path_sever(path, NULL);
 612                 iucv_path_free(path);
 613         }
 614 }
 615
 616 /**
 617  * hvc_iucv_notifier_hangup() - HVC notifier for TTY hangups.
 618  * @hp:         Pointer to the HVC device (struct hvc_struct)
 619  * @id:         Additional data (originally passed to hvc_alloc):
 620  *              the index of an struct hvc_iucv_private instance.
 621  *
 622  * This routine notifies the HVC back-end that a tty hangup (carrier loss,
 623  * virtual or otherwise) has occured.
 624  * The z/VM IUCV HVC device driver ignores virtual hangups (vhangup())
 625  * to keep an existing IUCV communication path established.
 626  * (Background: vhangup() is called from user space (by getty or login) to
 627  *              disable writing to the tty by other applications).
 628  * If the tty has been opened and an established IUCV path has been severed
 629  * (we caused the tty hangup), the function calls hvc_iucv_cleanup().
 630  *
 631  * Locking:     struct hvc_iucv_private->lock
 632  */
 633 static void hvc_iucv_notifier_hangup(struct hvc_struct *hp, int id)
 634 {
 635         struct hvc_iucv_private *priv;
 636
 637         priv = hvc_iucv_get_private(id);
 638         if (!priv)
 639                 return;
 640
 641         flush_sndbuf_sync(priv);
 642
 643         spin_lock_bh(&priv->lock);
 644         /* NOTE: If the hangup was scheduled by ourself (from the iucv
 645          *       path_servered callback [IUCV_SEVERED]), we have to clean up
 646          *       our structure and to set state to TTY_CLOSED.
 647          *       If the tty was hung up otherwise (e.g. vhangup()), then we
 648          *       ignore this hangup and keep an established IUCV path open...
 649          *       (...the reason is that we are not able to connect back to the
 650          *       client if we disconnect on hang up) */
 651         priv->tty_state = TTY_CLOSED;
 652
 653         if (priv->iucv_state == IUCV_SEVERED)
 654                 hvc_iucv_cleanup(priv);
 655         spin_unlock_bh(&priv->lock);
 656 }
 657
 658 /**
 659  * hvc_iucv_notifier_del() - HVC notifier for closing a TTY for the last time.
 660  * @hp:         Pointer to the HVC device (struct hvc_struct)
 661  * @id:         Additional data (originally passed to hvc_alloc):
 662  *              the index of an struct hvc_iucv_private instance.
 663  *
 664  * This routine notifies the HVC back-end that the last tty device fd has been
 665  * closed.  The function calls hvc_iucv_cleanup() to clean up the struct
 666  * hvc_iucv_private instance.
 667  *
 668  * Locking:     struct hvc_iucv_private->lock
 669  */
 670 static void hvc_iucv_notifier_del(struct hvc_struct *hp, int id)
 671 {
 672         struct hvc_iucv_private *priv;
 673         struct iucv_path        *path;
 674
 675         priv = hvc_iucv_get_private(id);
 676         if (!priv)
 677                 return;
 678
 679         flush_sndbuf_sync(priv);
 680
 681         spin_lock_bh(&priv->lock);
 682         path = priv->path;              /* save reference to IUCV path */
 683         priv->path = NULL;
 684         hvc_iucv_cleanup(priv);
 685         spin_unlock_bh(&priv->lock);
 686
 687         /* sever IUCV path outside of priv->lock due to lock ordering of:
 688          * priv->lock <--> iucv_table_lock */
 689         if (path) {
 690                 iucv_path_sever(path, NULL);
 691                 iucv_path_free(path);
 692         }
 693 }
 694
 695 /**
 696  * hvc_iucv_filter_connreq() - Filter connection request based on z/VM user ID
 697  * @ipvmid:     Originating z/VM user ID (right padded with blanks)
 698  *
 699  * Returns 0 if the z/VM user ID @ipvmid is allowed to connection, otherwise
 700  * non-zero.
 701  */
 702 static int hvc_iucv_filter_connreq(u8 ipvmid[8])
 703 {
 704         size_t i;
 705
 706         /* Note: default policy is ACCEPT if no filter is set */
 707         if (!hvc_iucv_filter_size)
 708                 return 0;
 709
 710         for (i = 0; i < hvc_iucv_filter_size; i++)
 711                 if (0 == memcmp(ipvmid, hvc_iucv_filter + (8 * i), 8))
 712                         return 0;
 713         return 1;
 714 }
 715
 716 /**
 717  * hvc_iucv_path_pending() - IUCV handler to process a connection request.
 718  * @path:       Pending path (struct iucv_path)
 719  * @ipvmid:     z/VM system identifier of originator
 720  * @ipuser:     User specified data for this path
 721  *              (AF_IUCV: port/service name and originator port)
 722  *
 723  * The function uses the @ipuser data to determine if the pending path belongs
 724  * to a terminal managed by this device driver.
 725  * If the path belongs to this driver, ensure that the terminal is not accessed
 726  * multiple times (only one connection to a terminal is allowed).
 727  * If the terminal is not yet connected, the pending path is accepted and is
 728  * associated to the appropriate struct hvc_iucv_private instance.
 729  *
 730  * Returns 0 if @path belongs to a terminal managed by the this device driver;
 731  * otherwise returns -ENODEV in order to dispatch this path to other handlers.
 732  *
 733  * Locking:     struct hvc_iucv_private->lock
 734  */
 735 static  int hvc_iucv_path_pending(struct iucv_path *path,
 736                                   u8 ipvmid[8], u8 ipuser[16])
 737 {
 738         struct hvc_iucv_private *priv;
 739         u8 nuser_data[16];
 740         u8 vm_user_id[9];
 741         int i, rc;
 742
 743         priv = NULL;
 744         for (i = 0; i < hvc_iucv_devices; i++)
 745                 if (hvc_iucv_table[i] &&
 746                     (0 == memcmp(hvc_iucv_table[i]->srv_name, ipuser, 8))) {
 747                         priv = hvc_iucv_table[i];
 748                         break;
 749                 }
 750         if (!priv)
 751                 return -ENODEV;
 752
 753         /* Enforce that ipvmid is allowed to connect to us */
 754         read_lock(&hvc_iucv_filter_lock);
 755         rc = hvc_iucv_filter_connreq(ipvmid);
 756         read_unlock(&hvc_iucv_filter_lock);
 757         if (rc) {
 758                 iucv_path_sever(path, ipuser);
 759                 iucv_path_free(path);
 760                 memcpy(vm_user_id, ipvmid, 8);
 761                 vm_user_id[8] = 0;
 762                 pr_info("A connection request from z/VM user ID %s "
 763                         "was refused\n", vm_user_id);
 764                 return 0;
 765         }
 766
 767         spin_lock(&priv->lock);
 768
 769         /* If the terminal is already connected or being severed, then sever
 770          * this path to enforce that there is only ONE established communication
 771          * path per terminal. */
 772         if (priv->iucv_state != IUCV_DISCONN) {
 773                 iucv_path_sever(path, ipuser);
 774                 iucv_path_free(path);
 775                 goto out_path_handled;
 776         }
 777
 778         /* accept path */
 779         memcpy(nuser_data, ipuser + 8, 8);  /* remote service (for af_iucv) */
 780         memcpy(nuser_data + 8, ipuser, 8);  /* local service  (for af_iucv) */
 781         path->msglim = 0xffff;              /* IUCV MSGLIMIT */
 782         path->flags &= ~IUCV_IPRMDATA;      /* TODO: use IUCV_IPRMDATA */
 783         rc = iucv_path_accept(path, &hvc_iucv_handler, nuser_data, priv);
 784         if (rc) {
 785                 iucv_path_sever(path, ipuser);
 786                 iucv_path_free(path);
 787                 goto out_path_handled;
 788         }
 789         priv->path = path;
 790         priv->iucv_state = IUCV_CONNECTED;
 791
 792         /* flush buffered output data... */
 793         schedule_delayed_work(&priv->sndbuf_work, 5);
 794
 795 out_path_handled:
 796         spin_unlock(&priv->lock);
 797         return 0;
 798 }
 799
 800 /**
 801  * hvc_iucv_path_severed() - IUCV handler to process a path sever.
 802  * @path:       Pending path (struct iucv_path)
 803  * @ipuser:     User specified data for this path
 804  *              (AF_IUCV: port/service name and originator port)
 805  *
 806  * This function calls the hvc_iucv_hangup() function for the
 807  * respective IUCV HVC terminal.
 808  *
 809  * Locking:     struct hvc_iucv_private->lock
 810  */
 811 static void hvc_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
 812 {
 813         struct hvc_iucv_private *priv = path->private;
 814
 815         hvc_iucv_hangup(priv);
 816 }
 817
 818 /**
 819  * hvc_iucv_msg_pending() - IUCV handler to process an incoming IUCV message.
 820  * @path:       Pending path (struct iucv_path)
 821  * @msg:        Pointer to the IUCV message
 822  *
 823  * The function puts an incoming message on the input queue for later
 824  * processing (by hvc_iucv_get_chars() / hvc_iucv_write()).
 825  * If the tty has not yet been opened, the message is rejected.
 826  *
 827  * Locking:     struct hvc_iucv_private->lock
 828  */
 829 static void hvc_iucv_msg_pending(struct iucv_path *path,
 830                                  struct iucv_message *msg)
 831 {
 832         struct hvc_iucv_private *priv = path->private;
 833         struct iucv_tty_buffer *rb;
 834
 835         /* reject messages that exceed max size of iucv_tty_msg->datalen */
 836         if (msg->length > MSG_SIZE(MSG_MAX_DATALEN)) {
 837                 iucv_message_reject(path, msg);
 838                 return;
 839         }
 840
 841         spin_lock(&priv->lock);
 842
 843         /* reject messages if tty has not yet been opened */
 844         if (priv->tty_state == TTY_CLOSED) {
 845                 iucv_message_reject(path, msg);
 846                 goto unlock_return;
 847         }
 848
 849         /* allocate tty buffer to save iucv msg only */
 850         rb = alloc_tty_buffer(0, GFP_ATOMIC);
 851         if (!rb) {
 852                 iucv_message_reject(path, msg);
 853                 goto unlock_return;     /* -ENOMEM */
 854         }
 855         rb->msg = *msg;
 856
 857         list_add_tail(&rb->list, &priv->tty_inqueue);
 858
 859         hvc_kick();     /* wake up hvc thread */
 860
 861 unlock_return:
 862         spin_unlock(&priv->lock);
 863 }
 864
 865 /**
 866  * hvc_iucv_msg_complete() - IUCV handler to process message completion
 867  * @path:       Pending path (struct iucv_path)
 868  * @msg:        Pointer to the IUCV message
 869  *
 870  * The function is called upon completion of message delivery to remove the
 871  * message from the outqueue. Additional delivery information can be found
 872  * msg->audit: rejected messages (0x040000 (IPADRJCT)), and
 873  *             purged messages   (0x010000 (IPADPGNR)).
 874  *
 875  * Locking:     struct hvc_iucv_private->lock
 876  */
 877 static void hvc_iucv_msg_complete(struct iucv_path *path,
 878                                   struct iucv_message *msg)
 879 {
 880         struct hvc_iucv_private *priv = path->private;
 881         struct iucv_tty_buffer  *ent, *next;
 882         LIST_HEAD(list_remove);
 883
 884         spin_lock(&priv->lock);
 885         list_for_each_entry_safe(ent, next, &priv->tty_outqueue, list)
 886                 if (ent->msg.id == msg->id) {
 887                         list_move(&ent->list, &list_remove);
 888                         break;
 889                 }
 890         wake_up(&priv->sndbuf_waitq);
 891         spin_unlock(&priv->lock);
 892         destroy_tty_buffer_list(&list_remove);
 893 }
 894
 895 /**
 896  * hvc_iucv_pm_freeze() - Freeze PM callback
 897  * @dev:        IUVC HVC terminal device
 898  *
 899  * Sever an established IUCV communication path and
 900  * trigger a hang-up of the underlying HVC terminal.
 901  */
 902 static int hvc_iucv_pm_freeze(struct device *dev)
 903 {
 904         struct hvc_iucv_private *priv = dev_get_drvdata(dev);
 905
 906         local_bh_disable();
 907         hvc_iucv_hangup(priv);
 908         local_bh_enable();
 909
 910         return 0;
 911 }
 912
 913 /**
 914  * hvc_iucv_pm_restore_thaw() - Thaw and restore PM callback
 915  * @dev:        IUVC HVC terminal device
 916  *
 917  * Wake up the HVC thread to trigger hang-up and respective
 918  * HVC back-end notifier invocations.
 919  */
 920 static int hvc_iucv_pm_restore_thaw(struct device *dev)
 921 {
 922         hvc_kick();
 923         return 0;
 924 }
 925
 926
 927 /* HVC operations */
 928 static const struct hv_ops hvc_iucv_ops = {
 929         .get_chars = hvc_iucv_get_chars,
 930         .put_chars = hvc_iucv_put_chars,
 931         .notifier_add = hvc_iucv_notifier_add,
 932         .notifier_del = hvc_iucv_notifier_del,
 933         .notifier_hangup = hvc_iucv_notifier_hangup,
 934 };
 935
 936 /* Suspend / resume device operations */
 937 static const struct dev_pm_ops hvc_iucv_pm_ops = {
 938         .freeze   = hvc_iucv_pm_freeze,
 939         .thaw     = hvc_iucv_pm_restore_thaw,
 940         .restore  = hvc_iucv_pm_restore_thaw,
 941 };
 942
 943 /* IUCV HVC device driver */
 944 static struct device_driver hvc_iucv_driver = {
 945         .name = KMSG_COMPONENT,
 946         .bus  = &iucv_bus,
 947         .pm   = &hvc_iucv_pm_ops,
 948 };
 949
 950 /**
 951  * hvc_iucv_alloc() - Allocates a new struct hvc_iucv_private instance
 952  * @id:                 hvc_iucv_table index
 953  * @is_console:         Flag if the instance is used as Linux console
 954  *
 955  * This function allocates a new hvc_iucv_private structure and stores
 956  * the instance in hvc_iucv_table at index @id.
 957  * Returns 0 on success; otherwise non-zero.
 958  */
 959 static int __init hvc_iucv_alloc(int id, unsigned int is_console)
 960 {
 961         struct hvc_iucv_private *priv;
 962         char name[9];
 963         int rc;
 964
 965         priv = kzalloc(sizeof(struct hvc_iucv_private), GFP_KERNEL);
 966         if (!priv)
 967                 return -ENOMEM;
 968
 969         spin_lock_init(&priv->lock);
 970         INIT_LIST_HEAD(&priv->tty_outqueue);
 971         INIT_LIST_HEAD(&priv->tty_inqueue);
 972         INIT_DELAYED_WORK(&priv->sndbuf_work, hvc_iucv_sndbuf_work);
 973         init_waitqueue_head(&priv->sndbuf_waitq);
 974
 975         priv->sndbuf = (void *) get_zeroed_page(GFP_KERNEL);
 976         if (!priv->sndbuf) {
 977                 kfree(priv);
 978                 return -ENOMEM;
 979         }
 980
 981         /* set console flag */
 982         priv->is_console = is_console;
 983
 984         /* allocate hvc device */
 985         priv->hvc = hvc_alloc(HVC_IUCV_MAGIC + id, /*             PAGE_SIZE */
 986                               HVC_IUCV_MAGIC + id, &hvc_iucv_ops, 256);
 987         if (IS_ERR(priv->hvc)) {
 988                 rc = PTR_ERR(priv->hvc);
 989                 goto out_error_hvc;
 990         }
 991
 992         /* notify HVC thread instead of using polling */
 993         priv->hvc->irq_requested = 1;
 994
 995         /* setup iucv related information */
 996         snprintf(name, 9, "lnxhvc%-2d", id);
 997         memcpy(priv->srv_name, name, 8);
 998         ASCEBC(priv->srv_name, 8);
 999
1000         /* create and setup device */
1001         priv->dev = kzalloc(sizeof(*priv->dev), GFP_KERNEL);
1002         if (!priv->dev) {
1003                 rc = -ENOMEM;
1004                 goto out_error_dev;
1005         }
1006         dev_set_name(priv->dev, "hvc_iucv%d", id);
1007         dev_set_drvdata(priv->dev, priv);
1008         priv->dev->bus = &iucv_bus;
1009         priv->dev->parent = iucv_root;
1010         priv->dev->driver = &hvc_iucv_driver;
1011         priv->dev->release = (void (*)(struct device *)) kfree;
1012         rc = device_register(priv->dev);
1013         if (rc) {
1014                 put_device(priv->dev);
1015                 goto out_error_dev;
1016         }
1017
1018         hvc_iucv_table[id] = priv;
1019         return 0;
1020
1021 out_error_dev:
1022         hvc_remove(priv->hvc);
1023 out_error_hvc:
1024         free_page((unsigned long) priv->sndbuf);
1025         kfree(priv);
1026
1027         return rc;
1028 }
1029
1030 /**
1031  * hvc_iucv_destroy() - Destroy and free hvc_iucv_private instances
1032  */
1033 static void __init hvc_iucv_destroy(struct hvc_iucv_private *priv)
1034 {
1035         hvc_remove(priv->hvc);
1036         device_unregister(priv->dev);
1037         free_page((unsigned long) priv->sndbuf);
1038         kfree(priv);
1039 }
1040
1041 /**
1042  * hvc_iucv_parse_filter() - Parse filter for a single z/VM user ID
1043  * @filter:     String containing a comma-separated list of z/VM user IDs
1044  */
1045 static const char *hvc_iucv_parse_filter(const char *filter, char *dest)
1046 {
1047         const char *nextdelim, *residual;
1048         size_t len;
1049
1050         nextdelim = strchr(filter, ',');
1051         if (nextdelim) {
1052                 len = nextdelim - filter;
1053                 residual = nextdelim + 1;
1054         } else {
1055                 len = strlen(filter);
1056                 residual = filter + len;
1057         }
1058
1059         if (len == 0)
1060                 return ERR_PTR(-EINVAL);
1061
1062         /* check for '\n' (if called from sysfs) */
1063         if (filter[len - 1] == '\n')
1064                 len--;
1065
1066         if (len > 8)
1067                 return ERR_PTR(-EINVAL);
1068
1069         /* pad with blanks and save upper case version of user ID */
1070         memset(dest, ' ', 8);
1071         while (len--)
1072                 dest[len] = toupper(filter[len]);
1073         return residual;
1074 }
1075
1076 /**
1077  * hvc_iucv_setup_filter() - Set up z/VM user ID filter
1078  * @filter:     String consisting of a comma-separated list of z/VM user IDs
1079  *
1080  * The function parses the @filter string and creates an array containing
1081  * the list of z/VM user ID filter entries.
1082  * Return code 0 means success, -EINVAL if the filter is syntactically
1083  * incorrect, -ENOMEM if there was not enough memory to allocate the
1084  * filter list array, or -ENOSPC if too many z/VM user IDs have been specified.
1085  */
1086 static int hvc_iucv_setup_filter(const char *val)
1087 {
1088         const char *residual;
1089         int err;
1090         size_t size, count;
1091         void *array, *old_filter;
1092
1093         count = strlen(val);
1094         if (count == 0 || (count == 1 && val[0] == '\n')) {
1095                 size  = 0;
1096                 array = NULL;
1097                 goto out_replace_filter;        /* clear filter */
1098         }
1099
1100         /* count user IDs in order to allocate sufficient memory */
1101         size = 1;
1102         residual = val;
1103         while ((residual = strchr(residual, ',')) != NULL) {
1104                 residual++;
1105                 size++;
1106         }
1107
1108         /* check if the specified list exceeds the filter limit */
1109         if (size > MAX_VMID_FILTER)
1110                 return -ENOSPC;
1111
1112         array = kzalloc(size * 8, GFP_KERNEL);
1113         if (!array)
1114                 return -ENOMEM;
1115
1116         count = size;
1117         residual = val;
1118         while (*residual && count) {
1119                 residual = hvc_iucv_parse_filter(residual,
1120                                                  array + ((size - count) * 8));
1121                 if (IS_ERR(residual)) {
1122                         err = PTR_ERR(residual);
1123                         kfree(array);
1124                         goto out_err;
1125                 }
1126                 count--;
1127         }
1128
1129 out_replace_filter:
1130         write_lock_bh(&hvc_iucv_filter_lock);
1131         old_filter = hvc_iucv_filter;
1132         hvc_iucv_filter_size = size;
1133         hvc_iucv_filter = array;
1134         write_unlock_bh(&hvc_iucv_filter_lock);
1135         kfree(old_filter);
1136
1137         err = 0;
1138 out_err:
1139         return err;
1140 }
1141
1142 /**
1143  * param_set_vmidfilter() - Set z/VM user ID filter parameter
1144  * @val:        String consisting of a comma-separated list of z/VM user IDs
1145  * @kp:         Kernel parameter pointing to hvc_iucv_filter array
1146  *
1147  * The function sets up the z/VM user ID filter specified as comma-separated
1148  * list of user IDs in @val.
1149  * Note: If it is called early in the boot process, @val is stored and
1150  *       parsed later in hvc_iucv_init().
1151  */
1152 static int param_set_vmidfilter(const char *val, const struct kernel_param *kp)
1153 {
1154         int rc;
1155
1156         if (!MACHINE_IS_VM || !hvc_iucv_devices)
1157                 return -ENODEV;
1158
1159         if (!val)
1160                 return -EINVAL;
1161
1162         rc = 0;
1163         if (slab_is_available())
1164                 rc = hvc_iucv_setup_filter(val);
1165         else
1166                 hvc_iucv_filter_string = val;   /* defer... */
1167         return rc;
1168 }
1169
1170 /**
1171  * param_get_vmidfilter() - Get z/VM user ID filter
1172  * @buffer:     Buffer to store z/VM user ID filter,
1173  *              (buffer size assumption PAGE_SIZE)
1174  * @kp:         Kernel parameter pointing to the hvc_iucv_filter array
1175  *
1176  * The function stores the filter as a comma-separated list of z/VM user IDs
1177  * in @buffer. Typically, sysfs routines call this function for attr show.
1178  */
1179 static int param_get_vmidfilter(char *buffer, const struct kernel_param *kp)
1180 {
1181         int rc;
1182         size_t index, len;
1183         void *start, *end;
1184
1185         if (!MACHINE_IS_VM || !hvc_iucv_devices)
1186                 return -ENODEV;
1187
1188         rc = 0;
1189         read_lock_bh(&hvc_iucv_filter_lock);
1190         for (index = 0; index < hvc_iucv_filter_size; index++) {
1191                 start = hvc_iucv_filter + (8 * index);
1192                 end   = memchr(start, ' ', 8);
1193                 len   = (end) ? end - start : 8;
1194                 memcpy(buffer + rc, start, len);
1195                 rc += len;
1196                 buffer[rc++] = ',';
1197         }
1198         read_unlock_bh(&hvc_iucv_filter_lock);
1199         if (rc)
1200                 buffer[--rc] = '\0';    /* replace last comma and update rc */
1201         return rc;
1202 }
1203
1204 #define param_check_vmidfilter(name, p) __param_check(name, p, void)
1205
1206 static struct kernel_param_ops param_ops_vmidfilter = {
1207         .set = param_set_vmidfilter,
1208         .get = param_get_vmidfilter,
1209 };
1210
1211 /**
1212  * hvc_iucv_init() - z/VM IUCV HVC device driver initialization
1213  */
1214 static int __init hvc_iucv_init(void)
1215 {
1216         int rc;
1217         unsigned int i;
1218
1219         if (!hvc_iucv_devices)
1220                 return -ENODEV;
1221
1222         if (!MACHINE_IS_VM) {
1223                 pr_notice("The z/VM IUCV HVC device driver cannot "
1224                            "be used without z/VM\n");
1225                 rc = -ENODEV;
1226                 goto out_error;
1227         }
1228
1229         if (hvc_iucv_devices > MAX_HVC_IUCV_LINES) {
1230                 pr_err("%lu is not a valid value for the hvc_iucv= "
1231                         "kernel parameter\n", hvc_iucv_devices);
1232                 rc = -EINVAL;
1233                 goto out_error;
1234         }
1235
1236         /* register IUCV HVC device driver */
1237         rc = driver_register(&hvc_iucv_driver);
1238         if (rc)
1239                 goto out_error;
1240
1241         /* parse hvc_iucv_allow string and create z/VM user ID filter list */
1242         if (hvc_iucv_filter_string) {
1243                 rc = hvc_iucv_setup_filter(hvc_iucv_filter_string);
1244                 switch (rc) {
1245                 case 0:
1246                         break;
1247                 case -ENOMEM:
1248                         pr_err("Allocating memory failed with "
1249                                 "reason code=%d\n", 3);
1250                         goto out_error;
1251                 case -EINVAL:
1252                         pr_err("hvc_iucv_allow= does not specify a valid "
1253                                 "z/VM user ID list\n");
1254                         goto out_error;
1255                 case -ENOSPC:
1256                         pr_err("hvc_iucv_allow= specifies too many "
1257                                 "z/VM user IDs\n");
1258                         goto out_error;
1259                 default:
1260                         goto out_error;
1261                 }
1262         }
1263
1264         hvc_iucv_buffer_cache = kmem_cache_create(KMSG_COMPONENT,
1265                                            sizeof(struct iucv_tty_buffer),
1266                                            0, 0, NULL);
1267         if (!hvc_iucv_buffer_cache) {
1268                 pr_err("Allocating memory failed with reason code=%d\n", 1);
1269                 rc = -ENOMEM;
1270                 goto out_error;
1271         }
1272
1273         hvc_iucv_mempool = mempool_create_slab_pool(MEMPOOL_MIN_NR,
1274                                                     hvc_iucv_buffer_cache);
1275         if (!hvc_iucv_mempool) {
1276                 pr_err("Allocating memory failed with reason code=%d\n", 2);
1277                 kmem_cache_destroy(hvc_iucv_buffer_cache);
1278                 rc = -ENOMEM;
1279                 goto out_error;
1280         }
1281
1282         /* register the first terminal device as console
1283          * (must be done before allocating hvc terminal devices) */
1284         rc = hvc_instantiate(HVC_IUCV_MAGIC, IUCV_HVC_CON_IDX, &hvc_iucv_ops);
1285         if (rc) {
1286                 pr_err("Registering HVC terminal device as "
1287                        "Linux console failed\n");
1288                 goto out_error_memory;
1289         }
1290
1291         /* allocate hvc_iucv_private structs */
1292         for (i = 0; i < hvc_iucv_devices; i++) {
1293                 rc = hvc_iucv_alloc(i, (i == IUCV_HVC_CON_IDX) ? 1 : 0);
1294                 if (rc) {
1295                         pr_err("Creating a new HVC terminal device "
1296                                 "failed with error code=%d\n", rc);
1297                         goto out_error_hvc;
1298                 }
1299         }
1300
1301         /* register IUCV callback handler */
1302         rc = iucv_register(&hvc_iucv_handler, 0);
1303         if (rc) {
1304                 pr_err("Registering IUCV handlers failed with error code=%d\n",
1305                         rc);
1306                 goto out_error_hvc;
1307         }
1308
1309         return 0;
1310
1311 out_error_hvc:
1312         for (i = 0; i < hvc_iucv_devices; i++)
1313                 if (hvc_iucv_table[i])
1314                         hvc_iucv_destroy(hvc_iucv_table[i]);
1315 out_error_memory:
1316         mempool_destroy(hvc_iucv_mempool);
1317         kmem_cache_destroy(hvc_iucv_buffer_cache);
1318 out_error:
1319         if (hvc_iucv_filter)
1320                 kfree(hvc_iucv_filter);
1321         hvc_iucv_devices = 0; /* ensure that we do not provide any device */
1322         return rc;
1323 }
1324
1325 /**
1326  * hvc_iucv_config() - Parsing of hvc_iucv=  kernel command line parameter
1327  * @val:        Parameter value (numeric)
1328  */
1329 static  int __init hvc_iucv_config(char *val)
1330 {
1331          return strict_strtoul(val, 10, &hvc_iucv_devices);
1332 }
1333
1334
1335 device_initcall(hvc_iucv_init);
1336 __setup("hvc_iucv=", hvc_iucv_config);
1337 core_param(hvc_iucv_allow, hvc_iucv_filter, vmidfilter, 0640);