drivers/tty/hvc/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         u8                      info_path[16];  /* IUCV path info (dev attr) */
  81 };
  82
  83 struct iucv_tty_buffer {
  84         struct list_head        list;   /* list pointer */
  85         struct iucv_message     msg;    /* store an IUCV message */
  86         size_t                  offset; /* data buffer offset */
  87         struct iucv_tty_msg     *mbuf;  /* buffer to store input/output data */
  88 };
  89
  90 /* IUCV callback handler */
  91 static  int hvc_iucv_path_pending(struct iucv_path *, u8[8], u8[16]);
  92 static void hvc_iucv_path_severed(struct iucv_path *, u8[16]);
  93 static void hvc_iucv_msg_pending(struct iucv_path *, struct iucv_message *);
  94 static void hvc_iucv_msg_complete(struct iucv_path *, struct iucv_message *);
  95
  96
  97 /* Kernel module parameter: use one terminal device as default */
  98 static unsigned long hvc_iucv_devices = 1;
  99
 100 /* Array of allocated hvc iucv tty lines... */
 101 static struct hvc_iucv_private *hvc_iucv_table[MAX_HVC_IUCV_LINES];
 102 #define IUCV_HVC_CON_IDX        (0)
 103 /* List of z/VM user ID filter entries (struct iucv_vmid_filter) */
 104 #define MAX_VMID_FILTER         (500)
 105 static size_t hvc_iucv_filter_size;
 106 static void *hvc_iucv_filter;
 107 static const char *hvc_iucv_filter_string;
 108 static DEFINE_RWLOCK(hvc_iucv_filter_lock);
 109
 110 /* Kmem cache and mempool for iucv_tty_buffer elements */
 111 static struct kmem_cache *hvc_iucv_buffer_cache;
 112 static mempool_t *hvc_iucv_mempool;
 113
 114 /* IUCV handler callback functions */
 115 static struct iucv_handler hvc_iucv_handler = {
 116         .path_pending  = hvc_iucv_path_pending,
 117         .path_severed  = hvc_iucv_path_severed,
 118         .message_complete = hvc_iucv_msg_complete,
 119         .message_pending  = hvc_iucv_msg_pending,
 120 };
 121
 122
 123 /**
 124  * hvc_iucv_get_private() - Return a struct hvc_iucv_private instance.
 125  * @num:        The HVC virtual terminal number (vtermno)
 126  *
 127  * This function returns the struct hvc_iucv_private instance that corresponds
 128  * to the HVC virtual terminal number specified as parameter @num.
 129  */
 130 static struct hvc_iucv_private *hvc_iucv_get_private(uint32_t num)
 131 {
 132         if ((num < HVC_IUCV_MAGIC) || (num - HVC_IUCV_MAGIC > hvc_iucv_devices))
 133                 return NULL;
 134         return hvc_iucv_table[num - HVC_IUCV_MAGIC];
 135 }
 136
 137 /**
 138  * alloc_tty_buffer() - Return a new struct iucv_tty_buffer element.
 139  * @size:       Size of the internal buffer used to store data.
 140  * @flags:      Memory allocation flags passed to mempool.
 141  *
 142  * This function allocates a new struct iucv_tty_buffer element and, optionally,
 143  * allocates an internal data buffer with the specified size @size.
 144  * The internal data buffer is always allocated with GFP_DMA which is
 145  * required for receiving and sending data with IUCV.
 146  * Note: The total message size arises from the internal buffer size and the
 147  *       members of the iucv_tty_msg structure.
 148  * The function returns NULL if memory allocation has failed.
 149  */
 150 static struct iucv_tty_buffer *alloc_tty_buffer(size_t size, gfp_t flags)
 151 {
 152         struct iucv_tty_buffer *bufp;
 153
 154         bufp = mempool_alloc(hvc_iucv_mempool, flags);
 155         if (!bufp)
 156                 return NULL;
 157         memset(bufp, 0, sizeof(*bufp));
 158
 159         if (size > 0) {
 160                 bufp->msg.length = MSG_SIZE(size);
 161                 bufp->mbuf = kmalloc(bufp->msg.length, flags | GFP_DMA);
 162                 if (!bufp->mbuf) {
 163                         mempool_free(bufp, hvc_iucv_mempool);
 164                         return NULL;
 165                 }
 166                 bufp->mbuf->version = MSG_VERSION;
 167                 bufp->mbuf->type    = MSG_TYPE_DATA;
 168                 bufp->mbuf->datalen = (u16) size;
 169         }
 170         return bufp;
 171 }
 172
 173 /**
 174  * destroy_tty_buffer() - destroy struct iucv_tty_buffer element.
 175  * @bufp:       Pointer to a struct iucv_tty_buffer element, SHALL NOT be NULL.
 176  */
 177 static void destroy_tty_buffer(struct iucv_tty_buffer *bufp)
 178 {
 179         kfree(bufp->mbuf);
 180         mempool_free(bufp, hvc_iucv_mempool);
 181 }
 182
 183 /**
 184  * destroy_tty_buffer_list() - call destroy_tty_buffer() for each list element.
 185  * @list:       List containing struct iucv_tty_buffer elements.
 186  */
 187 static void destroy_tty_buffer_list(struct list_head *list)
 188 {
 189         struct iucv_tty_buffer *ent, *next;
 190
 191         list_for_each_entry_safe(ent, next, list, list) {
 192                 list_del(&ent->list);
 193                 destroy_tty_buffer(ent);
 194         }
 195 }
 196
 197 /**
 198  * hvc_iucv_write() - Receive IUCV message & write data to HVC buffer.
 199  * @priv:               Pointer to struct hvc_iucv_private
 200  * @buf:                HVC buffer for writing received terminal data.
 201  * @count:              HVC buffer size.
 202  * @has_more_data:      Pointer to an int variable.
 203  *
 204  * The function picks up pending messages from the input queue and receives
 205  * the message data that is then written to the specified buffer @buf.
 206  * If the buffer size @count is less than the data message size, the
 207  * message is kept on the input queue and @has_more_data is set to 1.
 208  * If all message data has been written, the message is removed from
 209  * the input queue.
 210  *
 211  * The function returns the number of bytes written to the terminal, zero if
 212  * there are no pending data messages available or if there is no established
 213  * IUCV path.
 214  * If the IUCV path has been severed, then -EPIPE is returned to cause a
 215  * hang up (that is issued by the HVC layer).
 216  */
 217 static int hvc_iucv_write(struct hvc_iucv_private *priv,
 218                           char *buf, int count, int *has_more_data)
 219 {
 220         struct iucv_tty_buffer *rb;
 221         int written;
 222         int rc;
 223
 224         /* immediately return if there is no IUCV connection */
 225         if (priv->iucv_state == IUCV_DISCONN)
 226                 return 0;
 227
 228         /* if the IUCV path has been severed, return -EPIPE to inform the
 229          * HVC layer to hang up the tty device. */
 230         if (priv->iucv_state == IUCV_SEVERED)
 231                 return -EPIPE;
 232
 233         /* check if there are pending messages */
 234         if (list_empty(&priv->tty_inqueue))
 235                 return 0;
 236
 237         /* receive an iucv message and flip data to the tty (ldisc) */
 238         rb = list_first_entry(&priv->tty_inqueue, struct iucv_tty_buffer, list);
 239
 240         written = 0;
 241         if (!rb->mbuf) { /* message not yet received ... */
 242                 /* allocate mem to store msg data; if no memory is available
 243                  * then leave the buffer on the list and re-try later */
 244                 rb->mbuf = kmalloc(rb->msg.length, GFP_ATOMIC | GFP_DMA);
 245                 if (!rb->mbuf)
 246                         return -ENOMEM;
 247
 248                 rc = __iucv_message_receive(priv->path, &rb->msg, 0,
 249                                             rb->mbuf, rb->msg.length, NULL);
 250                 switch (rc) {
 251                 case 0: /* Successful       */
 252                         break;
 253                 case 2: /* No message found */
 254                 case 9: /* Message purged   */
 255                         break;
 256                 default:
 257                         written = -EIO;
 258                 }
 259                 /* remove buffer if an error has occurred or received data
 260                  * is not correct */
 261                 if (rc || (rb->mbuf->version != MSG_VERSION) ||
 262                           (rb->msg.length    != MSG_SIZE(rb->mbuf->datalen)))
 263                         goto out_remove_buffer;
 264         }
 265
 266         switch (rb->mbuf->type) {
 267         case MSG_TYPE_DATA:
 268                 written = min_t(int, rb->mbuf->datalen - rb->offset, count);
 269                 memcpy(buf, rb->mbuf->data + rb->offset, written);
 270                 if (written < (rb->mbuf->datalen - rb->offset)) {
 271                         rb->offset += written;
 272                         *has_more_data = 1;
 273                         goto out_written;
 274                 }
 275                 break;
 276
 277         case MSG_TYPE_WINSIZE:
 278                 if (rb->mbuf->datalen != sizeof(struct winsize))
 279                         break;
 280                 /* The caller must ensure that the hvc is locked, which
 281                  * is the case when called from hvc_iucv_get_chars() */
 282                 __hvc_resize(priv->hvc, *((struct winsize *) rb->mbuf->data));
 283                 break;
 284
 285         case MSG_TYPE_ERROR:    /* ignored ... */
 286         case MSG_TYPE_TERMENV:  /* ignored ... */
 287         case MSG_TYPE_TERMIOS:  /* ignored ... */
 288                 break;
 289         }
 290
 291 out_remove_buffer:
 292         list_del(&rb->list);
 293         destroy_tty_buffer(rb);
 294         *has_more_data = !list_empty(&priv->tty_inqueue);
 295
 296 out_written:
 297         return written;
 298 }
 299
 300 /**
 301  * hvc_iucv_get_chars() - HVC get_chars operation.
 302  * @vtermno:    HVC virtual terminal number.
 303  * @buf:        Pointer to a buffer to store data
 304  * @count:      Size of buffer available for writing
 305  *
 306  * The HVC thread calls this method to read characters from the back-end.
 307  * If an IUCV communication path has been established, pending IUCV messages
 308  * are received and data is copied into buffer @buf up to @count bytes.
 309  *
 310  * Locking:     The routine gets called under an irqsave() spinlock; and
 311  *              the routine locks the struct hvc_iucv_private->lock to call
 312  *              helper functions.
 313  */
 314 static int hvc_iucv_get_chars(uint32_t vtermno, char *buf, int count)
 315 {
 316         struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 317         int written;
 318         int has_more_data;
 319
 320         if (count <= 0)
 321                 return 0;
 322
 323         if (!priv)
 324                 return -ENODEV;
 325
 326         spin_lock(&priv->lock);
 327         has_more_data = 0;
 328         written = hvc_iucv_write(priv, buf, count, &has_more_data);
 329         spin_unlock(&priv->lock);
 330
 331         /* if there are still messages on the queue... schedule another run */
 332         if (has_more_data)
 333                 hvc_kick();
 334
 335         return written;
 336 }
 337
 338 /**
 339  * hvc_iucv_queue() - Buffer terminal data for sending.
 340  * @priv:       Pointer to struct hvc_iucv_private instance.
 341  * @buf:        Buffer containing data to send.
 342  * @count:      Size of buffer and amount of data to send.
 343  *
 344  * The function queues data for sending. To actually send the buffered data,
 345  * a work queue function is scheduled (with QUEUE_SNDBUF_DELAY).
 346  * The function returns the number of data bytes that has been buffered.
 347  *
 348  * If the device is not connected, data is ignored and the function returns
 349  * @count.
 350  * If the buffer is full, the function returns 0.
 351  * If an existing IUCV communicaton path has been severed, -EPIPE is returned
 352  * (that can be passed to HVC layer to cause a tty hangup).
 353  */
 354 static int hvc_iucv_queue(struct hvc_iucv_private *priv, const char *buf,
 355                           int count)
 356 {
 357         size_t len;
 358
 359         if (priv->iucv_state == IUCV_DISCONN)
 360                 return count;                   /* ignore data */
 361
 362         if (priv->iucv_state == IUCV_SEVERED)
 363                 return -EPIPE;
 364
 365         len = min_t(size_t, count, SNDBUF_SIZE - priv->sndbuf_len);
 366         if (!len)
 367                 return 0;
 368
 369         memcpy(priv->sndbuf + priv->sndbuf_len, buf, len);
 370         priv->sndbuf_len += len;
 371
 372         if (priv->iucv_state == IUCV_CONNECTED)
 373                 schedule_delayed_work(&priv->sndbuf_work, QUEUE_SNDBUF_DELAY);
 374
 375         return len;
 376 }
 377
 378 /**
 379  * hvc_iucv_send() - Send an IUCV message containing terminal data.
 380  * @priv:       Pointer to struct hvc_iucv_private instance.
 381  *
 382  * If an IUCV communication path has been established, the buffered output data
 383  * is sent via an IUCV message and the number of bytes sent is returned.
 384  * Returns 0 if there is no established IUCV communication path or
 385  * -EPIPE if an existing IUCV communicaton path has been severed.
 386  */
 387 static int hvc_iucv_send(struct hvc_iucv_private *priv)
 388 {
 389         struct iucv_tty_buffer *sb;
 390         int rc, len;
 391
 392         if (priv->iucv_state == IUCV_SEVERED)
 393                 return -EPIPE;
 394
 395         if (priv->iucv_state == IUCV_DISCONN)
 396                 return -EIO;
 397
 398         if (!priv->sndbuf_len)
 399                 return 0;
 400
 401         /* allocate internal buffer to store msg data and also compute total
 402          * message length */
 403         sb = alloc_tty_buffer(priv->sndbuf_len, GFP_ATOMIC);
 404         if (!sb)
 405                 return -ENOMEM;
 406
 407         memcpy(sb->mbuf->data, priv->sndbuf, priv->sndbuf_len);
 408         sb->mbuf->datalen = (u16) priv->sndbuf_len;
 409         sb->msg.length = MSG_SIZE(sb->mbuf->datalen);
 410
 411         list_add_tail(&sb->list, &priv->tty_outqueue);
 412
 413         rc = __iucv_message_send(priv->path, &sb->msg, 0, 0,
 414                                  (void *) sb->mbuf, sb->msg.length);
 415         if (rc) {
 416                 /* drop the message here; however we might want to handle
 417                  * 0x03 (msg limit reached) by trying again... */
 418                 list_del(&sb->list);
 419                 destroy_tty_buffer(sb);
 420         }
 421         len = priv->sndbuf_len;
 422         priv->sndbuf_len = 0;
 423
 424         return len;
 425 }
 426
 427 /**
 428  * hvc_iucv_sndbuf_work() - Send buffered data over IUCV
 429  * @work:       Work structure.
 430  *
 431  * This work queue function sends buffered output data over IUCV and,
 432  * if not all buffered data could be sent, reschedules itself.
 433  */
 434 static void hvc_iucv_sndbuf_work(struct work_struct *work)
 435 {
 436         struct hvc_iucv_private *priv;
 437
 438         priv = container_of(work, struct hvc_iucv_private, sndbuf_work.work);
 439         if (!priv)
 440                 return;
 441
 442         spin_lock_bh(&priv->lock);
 443         hvc_iucv_send(priv);
 444         spin_unlock_bh(&priv->lock);
 445 }
 446
 447 /**
 448  * hvc_iucv_put_chars() - HVC put_chars operation.
 449  * @vtermno:    HVC virtual terminal number.
 450  * @buf:        Pointer to an buffer to read data from
 451  * @count:      Size of buffer available for reading
 452  *
 453  * The HVC thread calls this method to write characters to the back-end.
 454  * The function calls hvc_iucv_queue() to queue terminal data for sending.
 455  *
 456  * Locking:     The method gets called under an irqsave() spinlock; and
 457  *              locks struct hvc_iucv_private->lock.
 458  */
 459 static int hvc_iucv_put_chars(uint32_t vtermno, const char *buf, int count)
 460 {
 461         struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 462         int queued;
 463
 464         if (count <= 0)
 465                 return 0;
 466
 467         if (!priv)
 468                 return -ENODEV;
 469
 470         spin_lock(&priv->lock);
 471         queued = hvc_iucv_queue(priv, buf, count);
 472         spin_unlock(&priv->lock);
 473
 474         return queued;
 475 }
 476
 477 /**
 478  * hvc_iucv_notifier_add() - HVC notifier for opening a TTY for the first time.
 479  * @hp: Pointer to the HVC device (struct hvc_struct)
 480  * @id: Additional data (originally passed to hvc_alloc): the index of an struct
 481  *      hvc_iucv_private instance.
 482  *
 483  * The function sets the tty state to TTY_OPENED for the struct hvc_iucv_private
 484  * instance that is derived from @id. Always returns 0.
 485  *
 486  * Locking:     struct hvc_iucv_private->lock, spin_lock_bh
 487  */
 488 static int hvc_iucv_notifier_add(struct hvc_struct *hp, int id)
 489 {
 490         struct hvc_iucv_private *priv;
 491
 492         priv = hvc_iucv_get_private(id);
 493         if (!priv)
 494                 return 0;
 495
 496         spin_lock_bh(&priv->lock);
 497         priv->tty_state = TTY_OPENED;
 498         spin_unlock_bh(&priv->lock);
 499
 500         return 0;
 501 }
 502
 503 /**
 504  * hvc_iucv_cleanup() - Clean up and reset a z/VM IUCV HVC instance.
 505  * @priv:       Pointer to the struct hvc_iucv_private instance.
 506  */
 507 static void hvc_iucv_cleanup(struct hvc_iucv_private *priv)
 508 {
 509         destroy_tty_buffer_list(&priv->tty_outqueue);
 510         destroy_tty_buffer_list(&priv->tty_inqueue);
 511
 512         priv->tty_state = TTY_CLOSED;
 513         priv->iucv_state = IUCV_DISCONN;
 514
 515         priv->sndbuf_len = 0;
 516 }
 517
 518 /**
 519  * tty_outqueue_empty() - Test if the tty outq is empty
 520  * @priv:       Pointer to struct hvc_iucv_private instance.
 521  */
 522 static inline int tty_outqueue_empty(struct hvc_iucv_private *priv)
 523 {
 524         int rc;
 525
 526         spin_lock_bh(&priv->lock);
 527         rc = list_empty(&priv->tty_outqueue);
 528         spin_unlock_bh(&priv->lock);
 529
 530         return rc;
 531 }
 532
 533 /**
 534  * flush_sndbuf_sync() - Flush send buffer and wait for completion
 535  * @priv:       Pointer to struct hvc_iucv_private instance.
 536  *
 537  * The routine cancels a pending sndbuf work, calls hvc_iucv_send()
 538  * to flush any buffered terminal output data and waits for completion.
 539  */
 540 static void flush_sndbuf_sync(struct hvc_iucv_private *priv)
 541 {
 542         int sync_wait;
 543
 544         cancel_delayed_work_sync(&priv->sndbuf_work);
 545
 546         spin_lock_bh(&priv->lock);
 547         hvc_iucv_send(priv);            /* force sending buffered data */
 548         sync_wait = !list_empty(&priv->tty_outqueue); /* anything queued ? */
 549         spin_unlock_bh(&priv->lock);
 550
 551         if (sync_wait)
 552                 wait_event_timeout(priv->sndbuf_waitq,
 553                                    tty_outqueue_empty(priv), HZ/10);
 554 }
 555
 556 /**
 557  * hvc_iucv_hangup() - Sever IUCV path and schedule hvc tty hang up
 558  * @priv:       Pointer to hvc_iucv_private structure
 559  *
 560  * This routine severs an existing IUCV communication path and hangs
 561  * up the underlying HVC terminal device.
 562  * The hang-up occurs only if an IUCV communication path is established;
 563  * otherwise there is no need to hang up the terminal device.
 564  *
 565  * The IUCV HVC hang-up is separated into two steps:
 566  * 1. After the IUCV path has been severed, the iucv_state is set to
 567  *    IUCV_SEVERED.
 568  * 2. Later, when the HVC thread calls hvc_iucv_get_chars(), the
 569  *    IUCV_SEVERED state causes the tty hang-up in the HVC layer.
 570  *
 571  * If the tty has not yet been opened, clean up the hvc_iucv_private
 572  * structure to allow re-connects.
 573  * If the tty has been opened, let get_chars() return -EPIPE to signal
 574  * the HVC layer to hang up the tty and, if so, wake up the HVC thread
 575  * to call get_chars()...
 576  *
 577  * Special notes on hanging up a HVC terminal instantiated as console:
 578  * Hang-up:     1. do_tty_hangup() replaces file ops (= hung_up_tty_fops)
 579  *              2. do_tty_hangup() calls tty->ops->close() for console_filp
 580  *                      => no hangup notifier is called by HVC (default)
 581  *              2. hvc_close() returns because of tty_hung_up_p(filp)
 582  *                      => no delete notifier is called!
 583  * Finally, the back-end is not being notified, thus, the tty session is
 584  * kept active (TTY_OPEN) to be ready for re-connects.
 585  *
 586  * Locking:     spin_lock(&priv->lock) w/o disabling bh
 587  */
 588 static void hvc_iucv_hangup(struct hvc_iucv_private *priv)
 589 {
 590         struct iucv_path *path;
 591
 592         path = NULL;
 593         spin_lock(&priv->lock);
 594         if (priv->iucv_state == IUCV_CONNECTED) {
 595                 path = priv->path;
 596                 priv->path = NULL;
 597                 priv->iucv_state = IUCV_SEVERED;
 598                 if (priv->tty_state == TTY_CLOSED)
 599                         hvc_iucv_cleanup(priv);
 600                 else
 601                         /* console is special (see above) */
 602                         if (priv->is_console) {
 603                                 hvc_iucv_cleanup(priv);
 604                                 priv->tty_state = TTY_OPENED;
 605                         } else
 606                                 hvc_kick();
 607         }
 608         spin_unlock(&priv->lock);
 609
 610         /* finally sever path (outside of priv->lock due to lock ordering) */
 611         if (path) {
 612                 iucv_path_sever(path, NULL);
 613                 iucv_path_free(path);
 614         }
 615 }
 616
 617 /**
 618  * hvc_iucv_notifier_hangup() - HVC notifier for TTY hangups.
 619  * @hp:         Pointer to the HVC device (struct hvc_struct)
 620  * @id:         Additional data (originally passed to hvc_alloc):
 621  *              the index of an struct hvc_iucv_private instance.
 622  *
 623  * This routine notifies the HVC back-end that a tty hangup (carrier loss,
 624  * virtual or otherwise) has occurred.
 625  * The z/VM IUCV HVC device driver ignores virtual hangups (vhangup())
 626  * to keep an existing IUCV communication path established.
 627  * (Background: vhangup() is called from user space (by getty or login) to
 628  *              disable writing to the tty by other applications).
 629  * If the tty has been opened and an established IUCV path has been severed
 630  * (we caused the tty hangup), the function calls hvc_iucv_cleanup().
 631  *
 632  * Locking:     struct hvc_iucv_private->lock
 633  */
 634 static void hvc_iucv_notifier_hangup(struct hvc_struct *hp, int id)
 635 {
 636         struct hvc_iucv_private *priv;
 637
 638         priv = hvc_iucv_get_private(id);
 639         if (!priv)
 640                 return;
 641
 642         flush_sndbuf_sync(priv);
 643
 644         spin_lock_bh(&priv->lock);
 645         /* NOTE: If the hangup was scheduled by ourself (from the iucv
 646          *       path_servered callback [IUCV_SEVERED]), we have to clean up
 647          *       our structure and to set state to TTY_CLOSED.
 648          *       If the tty was hung up otherwise (e.g. vhangup()), then we
 649          *       ignore this hangup and keep an established IUCV path open...
 650          *       (...the reason is that we are not able to connect back to the
 651          *       client if we disconnect on hang up) */
 652         priv->tty_state = TTY_CLOSED;
 653
 654         if (priv->iucv_state == IUCV_SEVERED)
 655                 hvc_iucv_cleanup(priv);
 656         spin_unlock_bh(&priv->lock);
 657 }
 658
 659 /**
 660  * hvc_iucv_dtr_rts() - HVC notifier for handling DTR/RTS
 661  * @hp:         Pointer the HVC device (struct hvc_struct)
 662  * @raise:      Non-zero to raise or zero to lower DTR/RTS lines
 663  *
 664  * This routine notifies the HVC back-end to raise or lower DTR/RTS
 665  * lines.  Raising DTR/RTS is ignored.  Lowering DTR/RTS indicates to
 666  * drop the IUCV connection (similar to hang up the modem).
 667  */
 668 static void hvc_iucv_dtr_rts(struct hvc_struct *hp, int raise)
 669 {
 670         struct hvc_iucv_private *priv;
 671         struct iucv_path        *path;
 672
 673         /* Raising the DTR/RTS is ignored as IUCV connections can be
 674          * established at any times.
 675          */
 676         if (raise)
 677                 return;
 678
 679         priv = hvc_iucv_get_private(hp->vtermno);
 680         if (!priv)
 681                 return;
 682
 683         /* Lowering the DTR/RTS lines disconnects an established IUCV
 684          * connection.
 685          */
 686         flush_sndbuf_sync(priv);
 687
 688         spin_lock_bh(&priv->lock);
 689         path = priv->path;              /* save reference to IUCV path */
 690         priv->path = NULL;
 691         priv->iucv_state = IUCV_DISCONN;
 692         spin_unlock_bh(&priv->lock);
 693
 694         /* Sever IUCV path outside of priv->lock due to lock ordering of:
 695          * priv->lock <--> iucv_table_lock */
 696         if (path) {
 697                 iucv_path_sever(path, NULL);
 698                 iucv_path_free(path);
 699         }
 700 }
 701
 702 /**
 703  * hvc_iucv_notifier_del() - HVC notifier for closing a TTY for the last time.
 704  * @hp:         Pointer to the HVC device (struct hvc_struct)
 705  * @id:         Additional data (originally passed to hvc_alloc):
 706  *              the index of an struct hvc_iucv_private instance.
 707  *
 708  * This routine notifies the HVC back-end that the last tty device fd has been
 709  * closed.  The function cleans up tty resources.  The clean-up of the IUCV
 710  * connection is done in hvc_iucv_dtr_rts() and depends on the HUPCL termios
 711  * control setting.
 712  *
 713  * Locking:     struct hvc_iucv_private->lock
 714  */
 715 static void hvc_iucv_notifier_del(struct hvc_struct *hp, int id)
 716 {
 717         struct hvc_iucv_private *priv;
 718
 719         priv = hvc_iucv_get_private(id);
 720         if (!priv)
 721                 return;
 722
 723         flush_sndbuf_sync(priv);
 724
 725         spin_lock_bh(&priv->lock);
 726         destroy_tty_buffer_list(&priv->tty_outqueue);
 727         destroy_tty_buffer_list(&priv->tty_inqueue);
 728         priv->tty_state = TTY_CLOSED;
 729         priv->sndbuf_len = 0;
 730         spin_unlock_bh(&priv->lock);
 731 }
 732
 733 /**
 734  * hvc_iucv_filter_connreq() - Filter connection request based on z/VM user ID
 735  * @ipvmid:     Originating z/VM user ID (right padded with blanks)
 736  *
 737  * Returns 0 if the z/VM user ID @ipvmid is allowed to connection, otherwise
 738  * non-zero.
 739  */
 740 static int hvc_iucv_filter_connreq(u8 ipvmid[8])
 741 {
 742         size_t i;
 743
 744         /* Note: default policy is ACCEPT if no filter is set */
 745         if (!hvc_iucv_filter_size)
 746                 return 0;
 747
 748         for (i = 0; i < hvc_iucv_filter_size; i++)
 749                 if (0 == memcmp(ipvmid, hvc_iucv_filter + (8 * i), 8))
 750                         return 0;
 751         return 1;
 752 }
 753
 754 /**
 755  * hvc_iucv_path_pending() - IUCV handler to process a connection request.
 756  * @path:       Pending path (struct iucv_path)
 757  * @ipvmid:     z/VM system identifier of originator
 758  * @ipuser:     User specified data for this path
 759  *              (AF_IUCV: port/service name and originator port)
 760  *
 761  * The function uses the @ipuser data to determine if the pending path belongs
 762  * to a terminal managed by this device driver.
 763  * If the path belongs to this driver, ensure that the terminal is not accessed
 764  * multiple times (only one connection to a terminal is allowed).
 765  * If the terminal is not yet connected, the pending path is accepted and is
 766  * associated to the appropriate struct hvc_iucv_private instance.
 767  *
 768  * Returns 0 if @path belongs to a terminal managed by the this device driver;
 769  * otherwise returns -ENODEV in order to dispatch this path to other handlers.
 770  *
 771  * Locking:     struct hvc_iucv_private->lock
 772  */
 773 static  int hvc_iucv_path_pending(struct iucv_path *path,
 774                                   u8 ipvmid[8], u8 ipuser[16])
 775 {
 776         struct hvc_iucv_private *priv;
 777         u8 nuser_data[16];
 778         u8 vm_user_id[9];
 779         int i, rc;
 780
 781         priv = NULL;
 782         for (i = 0; i < hvc_iucv_devices; i++)
 783                 if (hvc_iucv_table[i] &&
 784                     (0 == memcmp(hvc_iucv_table[i]->srv_name, ipuser, 8))) {
 785                         priv = hvc_iucv_table[i];
 786                         break;
 787                 }
 788         if (!priv)
 789                 return -ENODEV;
 790
 791         /* Enforce that ipvmid is allowed to connect to us */
 792         read_lock(&hvc_iucv_filter_lock);
 793         rc = hvc_iucv_filter_connreq(ipvmid);
 794         read_unlock(&hvc_iucv_filter_lock);
 795         if (rc) {
 796                 iucv_path_sever(path, ipuser);
 797                 iucv_path_free(path);
 798                 memcpy(vm_user_id, ipvmid, 8);
 799                 vm_user_id[8] = 0;
 800                 pr_info("A connection request from z/VM user ID %s "
 801                         "was refused\n", vm_user_id);
 802                 return 0;
 803         }
 804
 805         spin_lock(&priv->lock);
 806
 807         /* If the terminal is already connected or being severed, then sever
 808          * this path to enforce that there is only ONE established communication
 809          * path per terminal. */
 810         if (priv->iucv_state != IUCV_DISCONN) {
 811                 iucv_path_sever(path, ipuser);
 812                 iucv_path_free(path);
 813                 goto out_path_handled;
 814         }
 815
 816         /* accept path */
 817         memcpy(nuser_data, ipuser + 8, 8);  /* remote service (for af_iucv) */
 818         memcpy(nuser_data + 8, ipuser, 8);  /* local service  (for af_iucv) */
 819         path->msglim = 0xffff;              /* IUCV MSGLIMIT */
 820         path->flags &= ~IUCV_IPRMDATA;      /* TODO: use IUCV_IPRMDATA */
 821         rc = iucv_path_accept(path, &hvc_iucv_handler, nuser_data, priv);
 822         if (rc) {
 823                 iucv_path_sever(path, ipuser);
 824                 iucv_path_free(path);
 825                 goto out_path_handled;
 826         }
 827         priv->path = path;
 828         priv->iucv_state = IUCV_CONNECTED;
 829
 830         /* store path information */
 831         memcpy(priv->info_path, ipvmid, 8);
 832         memcpy(priv->info_path + 8, ipuser + 8, 8);
 833
 834         /* flush buffered output data... */
 835         schedule_delayed_work(&priv->sndbuf_work, 5);
 836
 837 out_path_handled:
 838         spin_unlock(&priv->lock);
 839         return 0;
 840 }
 841
 842 /**
 843  * hvc_iucv_path_severed() - IUCV handler to process a path sever.
 844  * @path:       Pending path (struct iucv_path)
 845  * @ipuser:     User specified data for this path
 846  *              (AF_IUCV: port/service name and originator port)
 847  *
 848  * This function calls the hvc_iucv_hangup() function for the
 849  * respective IUCV HVC terminal.
 850  *
 851  * Locking:     struct hvc_iucv_private->lock
 852  */
 853 static void hvc_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
 854 {
 855         struct hvc_iucv_private *priv = path->private;
 856
 857         hvc_iucv_hangup(priv);
 858 }
 859
 860 /**
 861  * hvc_iucv_msg_pending() - IUCV handler to process an incoming IUCV message.
 862  * @path:       Pending path (struct iucv_path)
 863  * @msg:        Pointer to the IUCV message
 864  *
 865  * The function puts an incoming message on the input queue for later
 866  * processing (by hvc_iucv_get_chars() / hvc_iucv_write()).
 867  * If the tty has not yet been opened, the message is rejected.
 868  *
 869  * Locking:     struct hvc_iucv_private->lock
 870  */
 871 static void hvc_iucv_msg_pending(struct iucv_path *path,
 872                                  struct iucv_message *msg)
 873 {
 874         struct hvc_iucv_private *priv = path->private;
 875         struct iucv_tty_buffer *rb;
 876
 877         /* reject messages that exceed max size of iucv_tty_msg->datalen */
 878         if (msg->length > MSG_SIZE(MSG_MAX_DATALEN)) {
 879                 iucv_message_reject(path, msg);
 880                 return;
 881         }
 882
 883         spin_lock(&priv->lock);
 884
 885         /* reject messages if tty has not yet been opened */
 886         if (priv->tty_state == TTY_CLOSED) {
 887                 iucv_message_reject(path, msg);
 888                 goto unlock_return;
 889         }
 890
 891         /* allocate tty buffer to save iucv msg only */
 892         rb = alloc_tty_buffer(0, GFP_ATOMIC);
 893         if (!rb) {
 894                 iucv_message_reject(path, msg);
 895                 goto unlock_return;     /* -ENOMEM */
 896         }
 897         rb->msg = *msg;
 898
 899         list_add_tail(&rb->list, &priv->tty_inqueue);
 900
 901         hvc_kick();     /* wake up hvc thread */
 902
 903 unlock_return:
 904         spin_unlock(&priv->lock);
 905 }
 906
 907 /**
 908  * hvc_iucv_msg_complete() - IUCV handler to process message completion
 909  * @path:       Pending path (struct iucv_path)
 910  * @msg:        Pointer to the IUCV message
 911  *
 912  * The function is called upon completion of message delivery to remove the
 913  * message from the outqueue. Additional delivery information can be found
 914  * msg->audit: rejected messages (0x040000 (IPADRJCT)), and
 915  *             purged messages   (0x010000 (IPADPGNR)).
 916  *
 917  * Locking:     struct hvc_iucv_private->lock
 918  */
 919 static void hvc_iucv_msg_complete(struct iucv_path *path,
 920                                   struct iucv_message *msg)
 921 {
 922         struct hvc_iucv_private *priv = path->private;
 923         struct iucv_tty_buffer  *ent, *next;
 924         LIST_HEAD(list_remove);
 925
 926         spin_lock(&priv->lock);
 927         list_for_each_entry_safe(ent, next, &priv->tty_outqueue, list)
 928                 if (ent->msg.id == msg->id) {
 929                         list_move(&ent->list, &list_remove);
 930                         break;
 931                 }
 932         wake_up(&priv->sndbuf_waitq);
 933         spin_unlock(&priv->lock);
 934         destroy_tty_buffer_list(&list_remove);
 935 }
 936
 937 /**
 938  * hvc_iucv_pm_freeze() - Freeze PM callback
 939  * @dev:        IUVC HVC terminal device
 940  *
 941  * Sever an established IUCV communication path and
 942  * trigger a hang-up of the underlying HVC terminal.
 943  */
 944 static int hvc_iucv_pm_freeze(struct device *dev)
 945 {
 946         struct hvc_iucv_private *priv = dev_get_drvdata(dev);
 947
 948         local_bh_disable();
 949         hvc_iucv_hangup(priv);
 950         local_bh_enable();
 951
 952         return 0;
 953 }
 954
 955 /**
 956  * hvc_iucv_pm_restore_thaw() - Thaw and restore PM callback
 957  * @dev:        IUVC HVC terminal device
 958  *
 959  * Wake up the HVC thread to trigger hang-up and respective
 960  * HVC back-end notifier invocations.
 961  */
 962 static int hvc_iucv_pm_restore_thaw(struct device *dev)
 963 {
 964         hvc_kick();
 965         return 0;
 966 }
 967
 968 static ssize_t hvc_iucv_dev_termid_show(struct device *dev,
 969                                         struct device_attribute *attr,
 970                                         char *buf)
 971 {
 972         struct hvc_iucv_private *priv = dev_get_drvdata(dev);
 973         size_t len;
 974
 975         len = sizeof(priv->srv_name);
 976         memcpy(buf, priv->srv_name, len);
 977         EBCASC(buf, len);
 978         buf[len++] = '\n';
 979         return len;
 980 }
 981
 982 static ssize_t hvc_iucv_dev_state_show(struct device *dev,
 983                                         struct device_attribute *attr,
 984                                         char *buf)
 985 {
 986         struct hvc_iucv_private *priv = dev_get_drvdata(dev);
 987         return sprintf(buf, "%u:%u\n", priv->iucv_state, priv->tty_state);
 988 }
 989
 990 static ssize_t hvc_iucv_dev_peer_show(struct device *dev,
 991                                       struct device_attribute *attr,
 992                                       char *buf)
 993 {
 994         struct hvc_iucv_private *priv = dev_get_drvdata(dev);
 995         char vmid[9], ipuser[9];
 996
 997         memset(vmid, 0, sizeof(vmid));
 998         memset(ipuser, 0, sizeof(ipuser));
 999
1000         spin_lock_bh(&priv->lock);
1001         if (priv->iucv_state == IUCV_CONNECTED) {
1002                 memcpy(vmid, priv->info_path, 8);
1003                 memcpy(ipuser, priv->info_path + 8, 8);
1004         }
1005         spin_unlock_bh(&priv->lock);
1006         EBCASC(ipuser, 8);
1007
1008         return sprintf(buf, "%s:%s\n", vmid, ipuser);
1009 }
1010
1011
1012 /* HVC operations */
1013 static const struct hv_ops hvc_iucv_ops = {
1014         .get_chars = hvc_iucv_get_chars,
1015         .put_chars = hvc_iucv_put_chars,
1016         .notifier_add = hvc_iucv_notifier_add,
1017         .notifier_del = hvc_iucv_notifier_del,
1018         .notifier_hangup = hvc_iucv_notifier_hangup,
1019         .dtr_rts = hvc_iucv_dtr_rts,
1020 };
1021
1022 /* Suspend / resume device operations */
1023 static const struct dev_pm_ops hvc_iucv_pm_ops = {
1024         .freeze   = hvc_iucv_pm_freeze,
1025         .thaw     = hvc_iucv_pm_restore_thaw,
1026         .restore  = hvc_iucv_pm_restore_thaw,
1027 };
1028
1029 /* IUCV HVC device driver */
1030 static struct device_driver hvc_iucv_driver = {
1031         .name = KMSG_COMPONENT,
1032         .bus  = &iucv_bus,
1033         .pm   = &hvc_iucv_pm_ops,
1034 };
1035
1036 /* IUCV HVC device attributes */
1037 static DEVICE_ATTR(termid, 0640, hvc_iucv_dev_termid_show, NULL);
1038 static DEVICE_ATTR(state, 0640, hvc_iucv_dev_state_show, NULL);
1039 static DEVICE_ATTR(peer, 0640, hvc_iucv_dev_peer_show, NULL);
1040 static struct attribute *hvc_iucv_dev_attrs[] = {
1041         &dev_attr_termid.attr,
1042         &dev_attr_state.attr,
1043         &dev_attr_peer.attr,
1044         NULL,
1045 };
1046 static struct attribute_group hvc_iucv_dev_attr_group = {
1047         .attrs = hvc_iucv_dev_attrs,
1048 };
1049 static const struct attribute_group *hvc_iucv_dev_attr_groups[] = {
1050         &hvc_iucv_dev_attr_group,
1051         NULL,
1052 };
1053
1054
1055 /**
1056  * hvc_iucv_alloc() - Allocates a new struct hvc_iucv_private instance
1057  * @id:                 hvc_iucv_table index
1058  * @is_console:         Flag if the instance is used as Linux console
1059  *
1060  * This function allocates a new hvc_iucv_private structure and stores
1061  * the instance in hvc_iucv_table at index @id.
1062  * Returns 0 on success; otherwise non-zero.
1063  */
1064 static int __init hvc_iucv_alloc(int id, unsigned int is_console)
1065 {
1066         struct hvc_iucv_private *priv;
1067         char name[9];
1068         int rc;
1069
1070         priv = kzalloc(sizeof(struct hvc_iucv_private), GFP_KERNEL);
1071         if (!priv)
1072                 return -ENOMEM;
1073
1074         spin_lock_init(&priv->lock);
1075         INIT_LIST_HEAD(&priv->tty_outqueue);
1076         INIT_LIST_HEAD(&priv->tty_inqueue);
1077         INIT_DELAYED_WORK(&priv->sndbuf_work, hvc_iucv_sndbuf_work);
1078         init_waitqueue_head(&priv->sndbuf_waitq);
1079
1080         priv->sndbuf = (void *) get_zeroed_page(GFP_KERNEL);
1081         if (!priv->sndbuf) {
1082                 kfree(priv);
1083                 return -ENOMEM;
1084         }
1085
1086         /* set console flag */
1087         priv->is_console = is_console;
1088
1089         /* allocate hvc device */
1090         priv->hvc = hvc_alloc(HVC_IUCV_MAGIC + id, /*             PAGE_SIZE */
1091                               HVC_IUCV_MAGIC + id, &hvc_iucv_ops, 256);
1092         if (IS_ERR(priv->hvc)) {
1093                 rc = PTR_ERR(priv->hvc);
1094                 goto out_error_hvc;
1095         }
1096
1097         /* notify HVC thread instead of using polling */
1098         priv->hvc->irq_requested = 1;
1099
1100         /* setup iucv related information */
1101         snprintf(name, 9, "lnxhvc%-2d", id);
1102         memcpy(priv->srv_name, name, 8);
1103         ASCEBC(priv->srv_name, 8);
1104
1105         /* create and setup device */
1106         priv->dev = kzalloc(sizeof(*priv->dev), GFP_KERNEL);
1107         if (!priv->dev) {
1108                 rc = -ENOMEM;
1109                 goto out_error_dev;
1110         }
1111         dev_set_name(priv->dev, "hvc_iucv%d", id);
1112         dev_set_drvdata(priv->dev, priv);
1113         priv->dev->bus = &iucv_bus;
1114         priv->dev->parent = iucv_root;
1115         priv->dev->driver = &hvc_iucv_driver;
1116         priv->dev->groups = hvc_iucv_dev_attr_groups;
1117         priv->dev->release = (void (*)(struct device *)) kfree;
1118         rc = device_register(priv->dev);
1119         if (rc) {
1120                 put_device(priv->dev);
1121                 goto out_error_dev;
1122         }
1123
1124         hvc_iucv_table[id] = priv;
1125         return 0;
1126
1127 out_error_dev:
1128         hvc_remove(priv->hvc);
1129 out_error_hvc:
1130         free_page((unsigned long) priv->sndbuf);
1131         kfree(priv);
1132
1133         return rc;
1134 }
1135
1136 /**
1137  * hvc_iucv_destroy() - Destroy and free hvc_iucv_private instances
1138  */
1139 static void __init hvc_iucv_destroy(struct hvc_iucv_private *priv)
1140 {
1141         hvc_remove(priv->hvc);
1142         device_unregister(priv->dev);
1143         free_page((unsigned long) priv->sndbuf);
1144         kfree(priv);
1145 }
1146
1147 /**
1148  * hvc_iucv_parse_filter() - Parse filter for a single z/VM user ID
1149  * @filter:     String containing a comma-separated list of z/VM user IDs
1150  */
1151 static const char *hvc_iucv_parse_filter(const char *filter, char *dest)
1152 {
1153         const char *nextdelim, *residual;
1154         size_t len;
1155
1156         nextdelim = strchr(filter, ',');
1157         if (nextdelim) {
1158                 len = nextdelim - filter;
1159                 residual = nextdelim + 1;
1160         } else {
1161                 len = strlen(filter);
1162                 residual = filter + len;
1163         }
1164
1165         if (len == 0)
1166                 return ERR_PTR(-EINVAL);
1167
1168         /* check for '\n' (if called from sysfs) */
1169         if (filter[len - 1] == '\n')
1170                 len--;
1171
1172         if (len > 8)
1173                 return ERR_PTR(-EINVAL);
1174
1175         /* pad with blanks and save upper case version of user ID */
1176         memset(dest, ' ', 8);
1177         while (len--)
1178                 dest[len] = toupper(filter[len]);
1179         return residual;
1180 }
1181
1182 /**
1183  * hvc_iucv_setup_filter() - Set up z/VM user ID filter
1184  * @filter:     String consisting of a comma-separated list of z/VM user IDs
1185  *
1186  * The function parses the @filter string and creates an array containing
1187  * the list of z/VM user ID filter entries.
1188  * Return code 0 means success, -EINVAL if the filter is syntactically
1189  * incorrect, -ENOMEM if there was not enough memory to allocate the
1190  * filter list array, or -ENOSPC if too many z/VM user IDs have been specified.
1191  */
1192 static int hvc_iucv_setup_filter(const char *val)
1193 {
1194         const char *residual;
1195         int err;
1196         size_t size, count;
1197         void *array, *old_filter;
1198
1199         count = strlen(val);
1200         if (count == 0 || (count == 1 && val[0] == '\n')) {
1201                 size  = 0;
1202                 array = NULL;
1203                 goto out_replace_filter;        /* clear filter */
1204         }
1205
1206         /* count user IDs in order to allocate sufficient memory */
1207         size = 1;
1208         residual = val;
1209         while ((residual = strchr(residual, ',')) != NULL) {
1210                 residual++;
1211                 size++;
1212         }
1213
1214         /* check if the specified list exceeds the filter limit */
1215         if (size > MAX_VMID_FILTER)
1216                 return -ENOSPC;
1217
1218         array = kzalloc(size * 8, GFP_KERNEL);
1219         if (!array)
1220                 return -ENOMEM;
1221
1222         count = size;
1223         residual = val;
1224         while (*residual && count) {
1225                 residual = hvc_iucv_parse_filter(residual,
1226                                                  array + ((size - count) * 8));
1227                 if (IS_ERR(residual)) {
1228                         err = PTR_ERR(residual);
1229                         kfree(array);
1230                         goto out_err;
1231                 }
1232                 count--;
1233         }
1234
1235 out_replace_filter:
1236         write_lock_bh(&hvc_iucv_filter_lock);
1237         old_filter = hvc_iucv_filter;
1238         hvc_iucv_filter_size = size;
1239         hvc_iucv_filter = array;
1240         write_unlock_bh(&hvc_iucv_filter_lock);
1241         kfree(old_filter);
1242
1243         err = 0;
1244 out_err:
1245         return err;
1246 }
1247
1248 /**
1249  * param_set_vmidfilter() - Set z/VM user ID filter parameter
1250  * @val:        String consisting of a comma-separated list of z/VM user IDs
1251  * @kp:         Kernel parameter pointing to hvc_iucv_filter array
1252  *
1253  * The function sets up the z/VM user ID filter specified as comma-separated
1254  * list of user IDs in @val.
1255  * Note: If it is called early in the boot process, @val is stored and
1256  *       parsed later in hvc_iucv_init().
1257  */
1258 static int param_set_vmidfilter(const char *val, const struct kernel_param *kp)
1259 {
1260         int rc;
1261
1262         if (!MACHINE_IS_VM || !hvc_iucv_devices)
1263                 return -ENODEV;
1264
1265         if (!val)
1266                 return -EINVAL;
1267
1268         rc = 0;
1269         if (slab_is_available())
1270                 rc = hvc_iucv_setup_filter(val);
1271         else
1272                 hvc_iucv_filter_string = val;   /* defer... */
1273         return rc;
1274 }
1275
1276 /**
1277  * param_get_vmidfilter() - Get z/VM user ID filter
1278  * @buffer:     Buffer to store z/VM user ID filter,
1279  *              (buffer size assumption PAGE_SIZE)
1280  * @kp:         Kernel parameter pointing to the hvc_iucv_filter array
1281  *
1282  * The function stores the filter as a comma-separated list of z/VM user IDs
1283  * in @buffer. Typically, sysfs routines call this function for attr show.
1284  */
1285 static int param_get_vmidfilter(char *buffer, const struct kernel_param *kp)
1286 {
1287         int rc;
1288         size_t index, len;
1289         void *start, *end;
1290
1291         if (!MACHINE_IS_VM || !hvc_iucv_devices)
1292                 return -ENODEV;
1293
1294         rc = 0;
1295         read_lock_bh(&hvc_iucv_filter_lock);
1296         for (index = 0; index < hvc_iucv_filter_size; index++) {
1297                 start = hvc_iucv_filter + (8 * index);
1298                 end   = memchr(start, ' ', 8);
1299                 len   = (end) ? end - start : 8;
1300                 memcpy(buffer + rc, start, len);
1301                 rc += len;
1302                 buffer[rc++] = ',';
1303         }
1304         read_unlock_bh(&hvc_iucv_filter_lock);
1305         if (rc)
1306                 buffer[--rc] = '\0';    /* replace last comma and update rc */
1307         return rc;
1308 }
1309
1310 #define param_check_vmidfilter(name, p) __param_check(name, p, void)
1311
1312 static struct kernel_param_ops param_ops_vmidfilter = {
1313         .set = param_set_vmidfilter,
1314         .get = param_get_vmidfilter,
1315 };
1316
1317 /**
1318  * hvc_iucv_init() - z/VM IUCV HVC device driver initialization
1319  */
1320 static int __init hvc_iucv_init(void)
1321 {
1322         int rc;
1323         unsigned int i;
1324
1325         if (!hvc_iucv_devices)
1326                 return -ENODEV;
1327
1328         if (!MACHINE_IS_VM) {
1329                 pr_notice("The z/VM IUCV HVC device driver cannot "
1330                            "be used without z/VM\n");
1331                 rc = -ENODEV;
1332                 goto out_error;
1333         }
1334
1335         if (hvc_iucv_devices > MAX_HVC_IUCV_LINES) {
1336                 pr_err("%lu is not a valid value for the hvc_iucv= "
1337                         "kernel parameter\n", hvc_iucv_devices);
1338                 rc = -EINVAL;
1339                 goto out_error;
1340         }
1341
1342         /* register IUCV HVC device driver */
1343         rc = driver_register(&hvc_iucv_driver);
1344         if (rc)
1345                 goto out_error;
1346
1347         /* parse hvc_iucv_allow string and create z/VM user ID filter list */
1348         if (hvc_iucv_filter_string) {
1349                 rc = hvc_iucv_setup_filter(hvc_iucv_filter_string);
1350                 switch (rc) {
1351                 case 0:
1352                         break;
1353                 case -ENOMEM:
1354                         pr_err("Allocating memory failed with "
1355                                 "reason code=%d\n", 3);
1356                         goto out_error;
1357                 case -EINVAL:
1358                         pr_err("hvc_iucv_allow= does not specify a valid "
1359                                 "z/VM user ID list\n");
1360                         goto out_error;
1361                 case -ENOSPC:
1362                         pr_err("hvc_iucv_allow= specifies too many "
1363                                 "z/VM user IDs\n");
1364                         goto out_error;
1365                 default:
1366                         goto out_error;
1367                 }
1368         }
1369
1370         hvc_iucv_buffer_cache = kmem_cache_create(KMSG_COMPONENT,
1371                                            sizeof(struct iucv_tty_buffer),
1372                                            0, 0, NULL);
1373         if (!hvc_iucv_buffer_cache) {
1374                 pr_err("Allocating memory failed with reason code=%d\n", 1);
1375                 rc = -ENOMEM;
1376                 goto out_error;
1377         }
1378
1379         hvc_iucv_mempool = mempool_create_slab_pool(MEMPOOL_MIN_NR,
1380                                                     hvc_iucv_buffer_cache);
1381         if (!hvc_iucv_mempool) {
1382                 pr_err("Allocating memory failed with reason code=%d\n", 2);
1383                 kmem_cache_destroy(hvc_iucv_buffer_cache);
1384                 rc = -ENOMEM;
1385                 goto out_error;
1386         }
1387
1388         /* register the first terminal device as console
1389          * (must be done before allocating hvc terminal devices) */
1390         rc = hvc_instantiate(HVC_IUCV_MAGIC, IUCV_HVC_CON_IDX, &hvc_iucv_ops);
1391         if (rc) {
1392                 pr_err("Registering HVC terminal device as "
1393                        "Linux console failed\n");
1394                 goto out_error_memory;
1395         }
1396
1397         /* allocate hvc_iucv_private structs */
1398         for (i = 0; i < hvc_iucv_devices; i++) {
1399                 rc = hvc_iucv_alloc(i, (i == IUCV_HVC_CON_IDX) ? 1 : 0);
1400                 if (rc) {
1401                         pr_err("Creating a new HVC terminal device "
1402                                 "failed with error code=%d\n", rc);
1403                         goto out_error_hvc;
1404                 }
1405         }
1406
1407         /* register IUCV callback handler */
1408         rc = iucv_register(&hvc_iucv_handler, 0);
1409         if (rc) {
1410                 pr_err("Registering IUCV handlers failed with error code=%d\n",
1411                         rc);
1412                 goto out_error_hvc;
1413         }
1414
1415         return 0;
1416
1417 out_error_hvc:
1418         for (i = 0; i < hvc_iucv_devices; i++)
1419                 if (hvc_iucv_table[i])
1420                         hvc_iucv_destroy(hvc_iucv_table[i]);
1421 out_error_memory:
1422         mempool_destroy(hvc_iucv_mempool);
1423         kmem_cache_destroy(hvc_iucv_buffer_cache);
1424 out_error:
1425         kfree(hvc_iucv_filter);
1426         hvc_iucv_devices = 0; /* ensure that we do not provide any device */
1427         return rc;
1428 }
1429
1430 /**
1431  * hvc_iucv_config() - Parsing of hvc_iucv=  kernel command line parameter
1432  * @val:        Parameter value (numeric)
1433  */
1434 static  int __init hvc_iucv_config(char *val)
1435 {
1436          return kstrtoul(val, 10, &hvc_iucv_devices);
1437 }
1438
1439
1440 device_initcall(hvc_iucv_init);
1441 __setup("hvc_iucv=", hvc_iucv_config);
1442 core_param(hvc_iucv_allow, hvc_iucv_filter, vmidfilter, 0640);