drivers/char/hvc_iucv.c

   1 /*
   2  * hvc_iucv.c - z/VM IUCV back-end for the Hypervisor Console (HVC)
   3  *
   4  * This back-end for HVC provides terminal access via
   5  * z/VM IUCV communication paths.
   6  *
   7  * Copyright IBM Corp. 2008.
   8  *
   9  * Author(s):   Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
  10  */
  11 #define KMSG_COMPONENT          "hvc_iucv"
  12
  13 #include <linux/types.h>
  14 #include <asm/ebcdic.h>
  15 #include <linux/delay.h>
  16 #include <linux/mempool.h>
  17 #include <linux/module.h>
  18 #include <linux/tty.h>
  19 #include <linux/wait.h>
  20 #include <net/iucv/iucv.h>
  21
  22 #include "hvc_console.h"
  23
  24
  25 /* HVC backend for z/VM IUCV */
  26 #define HVC_IUCV_MAGIC          0xc9e4c3e5
  27 #define MAX_HVC_IUCV_LINES      HVC_ALLOC_TTY_ADAPTERS
  28 #define MEMPOOL_MIN_NR          (PAGE_SIZE / sizeof(struct iucv_tty_buffer)/4)
  29
  30 /* IUCV TTY message  */
  31 #define MSG_VERSION             0x02    /* Message version */
  32 #define MSG_TYPE_ERROR          0x01    /* Error message */
  33 #define MSG_TYPE_TERMENV        0x02    /* Terminal environment variable */
  34 #define MSG_TYPE_TERMIOS        0x04    /* Terminal IO struct update */
  35 #define MSG_TYPE_WINSIZE        0x08    /* Terminal window size update */
  36 #define MSG_TYPE_DATA           0x10    /* Terminal data */
  37
  38 #define MSG_SIZE(s)             ((s) + offsetof(struct iucv_tty_msg, data))
  39 struct iucv_tty_msg {
  40         u8      version;                /* Message version */
  41         u8      type;                   /* Message type */
  42 #define MSG_MAX_DATALEN         ((u16)(~0))
  43         u16     datalen;                /* Payload length */
  44         u8      data[];                 /* Payload buffer */
  45 } __attribute__((packed));
  46
  47 enum iucv_state_t {
  48         IUCV_DISCONN    = 0,
  49         IUCV_CONNECTED  = 1,
  50         IUCV_SEVERED    = 2,
  51 };
  52
  53 enum tty_state_t {
  54         TTY_CLOSED      = 0,
  55         TTY_OPENED      = 1,
  56 };
  57
  58 struct hvc_iucv_private {
  59         struct hvc_struct       *hvc; /* HVC console struct reference */
  60         u8                      srv_name[8];    /* IUCV service name (ebcdic) */
  61         enum iucv_state_t       iucv_state;     /* IUCV connection status */
  62         enum tty_state_t        tty_state;      /* TTY status */
  63         struct iucv_path        *path;          /* IUCV path pointer */
  64         spinlock_t              lock;           /* hvc_iucv_private lock */
  65 #define SNDBUF_SIZE             (PAGE_SIZE)     /* must be < MSG_MAX_DATALEN */
  66         void                    *sndbuf;        /* send buffer            */
  67         size_t                  sndbuf_len;     /* length of send buffer  */
  68 #define QUEUE_SNDBUF_DELAY      (HZ / 25)
  69         struct delayed_work     sndbuf_work;    /* work: send iucv msg(s) */
  70         wait_queue_head_t       sndbuf_waitq;   /* wait for send completion */
  71         struct list_head        tty_outqueue;   /* outgoing IUCV messages */
  72         struct list_head        tty_inqueue;    /* incoming IUCV messages */
  73 };
  74
  75 struct iucv_tty_buffer {
  76         struct list_head        list;   /* list pointer */
  77         struct iucv_message     msg;    /* store an incoming IUCV message */
  78         size_t                  offset; /* data buffer offset */
  79         struct iucv_tty_msg     *mbuf;  /* buffer to store input/output data */
  80 };
  81
  82 /* IUCV callback handler */
  83 static  int hvc_iucv_path_pending(struct iucv_path *, u8[8], u8[16]);
  84 static void hvc_iucv_path_severed(struct iucv_path *, u8[16]);
  85 static void hvc_iucv_msg_pending(struct iucv_path *, struct iucv_message *);
  86 static void hvc_iucv_msg_complete(struct iucv_path *, struct iucv_message *);
  87
  88
  89 /* Kernel module parameter: use one terminal device as default */
  90 static unsigned long hvc_iucv_devices = 1;
  91
  92 /* Array of allocated hvc iucv tty lines... */
  93 static struct hvc_iucv_private *hvc_iucv_table[MAX_HVC_IUCV_LINES];
  94
  95 /* Kmem cache and mempool for iucv_tty_buffer elements */
  96 static struct kmem_cache *hvc_iucv_buffer_cache;
  97 static mempool_t *hvc_iucv_mempool;
  98
  99 /* IUCV handler callback functions */
 100 static struct iucv_handler hvc_iucv_handler = {
 101         .path_pending  = hvc_iucv_path_pending,
 102         .path_severed  = hvc_iucv_path_severed,
 103         .message_complete = hvc_iucv_msg_complete,
 104         .message_pending  = hvc_iucv_msg_pending,
 105 };
 106
 107
 108 /**
 109  * hvc_iucv_get_private() - Return a struct hvc_iucv_private instance.
 110  * @num:        The HVC virtual terminal number (vtermno)
 111  *
 112  * This function returns the struct hvc_iucv_private instance that corresponds
 113  * to the HVC virtual terminal number specified as parameter @num.
 114  */
 115 struct hvc_iucv_private *hvc_iucv_get_private(uint32_t num)
 116 {
 117         if ((num < HVC_IUCV_MAGIC) || (num - HVC_IUCV_MAGIC > hvc_iucv_devices))
 118                 return NULL;
 119         return hvc_iucv_table[num - HVC_IUCV_MAGIC];
 120 }
 121
 122 /**
 123  * alloc_tty_buffer() - Returns a new struct iucv_tty_buffer element.
 124  * @size:       Size of the internal buffer used to store data.
 125  * @flags:      Memory allocation flags passed to mempool.
 126  *
 127  * This function allocates a new struct iucv_tty_buffer element and, optionally,
 128  * allocates an internal data buffer with the specified size @size.
 129  * Note: The total message size arises from the internal buffer size and the
 130  *       members of the iucv_tty_msg structure.
 131  *
 132  * The function returns NULL if memory allocation has failed.
 133  */
 134 static struct iucv_tty_buffer *alloc_tty_buffer(size_t size, gfp_t flags)
 135 {
 136         struct iucv_tty_buffer *bufp;
 137
 138         bufp = mempool_alloc(hvc_iucv_mempool, flags);
 139         if (!bufp)
 140                 return NULL;
 141         memset(bufp, 0, sizeof(struct iucv_tty_buffer));
 142
 143         if (size > 0) {
 144                 bufp->msg.length = MSG_SIZE(size);
 145                 bufp->mbuf = kmalloc(bufp->msg.length, flags);
 146                 if (!bufp->mbuf) {
 147                         mempool_free(bufp, hvc_iucv_mempool);
 148                         return NULL;
 149                 }
 150                 bufp->mbuf->version = MSG_VERSION;
 151                 bufp->mbuf->type    = MSG_TYPE_DATA;
 152                 bufp->mbuf->datalen = (u16) size;
 153         }
 154         return bufp;
 155 }
 156
 157 /**
 158  * destroy_tty_buffer() - destroy struct iucv_tty_buffer element.
 159  * @bufp:       Pointer to a struct iucv_tty_buffer element, SHALL NOT be NULL.
 160  *
 161  * The destroy_tty_buffer() function frees the internal data buffer and returns
 162  * the struct iucv_tty_buffer element back to the mempool for freeing.
 163  */
 164 static void destroy_tty_buffer(struct iucv_tty_buffer *bufp)
 165 {
 166         kfree(bufp->mbuf);
 167         mempool_free(bufp, hvc_iucv_mempool);
 168 }
 169
 170 /**
 171  * destroy_tty_buffer_list() - call destroy_tty_buffer() for each list element.
 172  * @list:       List head pointer to a list containing struct iucv_tty_buffer
 173  *              elements.
 174  *
 175  * Calls destroy_tty_buffer() for each struct iucv_tty_buffer element in the
 176  * list @list.
 177  */
 178 static void destroy_tty_buffer_list(struct list_head *list)
 179 {
 180         struct iucv_tty_buffer *ent, *next;
 181
 182         list_for_each_entry_safe(ent, next, list, list) {
 183                 list_del(&ent->list);
 184                 destroy_tty_buffer(ent);
 185         }
 186 }
 187
 188 /**
 189  * hvc_iucv_write() - Receive IUCV message write data to HVC console buffer.
 190  * @priv:               Pointer to hvc_iucv_private structure.
 191  * @buf:                HVC console buffer for writing received terminal data.
 192  * @count:              HVC console buffer size.
 193  * @has_more_data:      Pointer to an int variable.
 194  *
 195  * The function picks up pending messages from the input queue and receives
 196  * the message data that is then written to the specified buffer @buf.
 197  * If the buffer size @count is less than the data message size, then the
 198  * message is kept on the input queue and @has_more_data is set to 1.
 199  * If the message data has been entirely written, the message is removed from
 200  * the input queue.
 201  *
 202  * The function returns the number of bytes written to the terminal, zero if
 203  * there are no pending data messages available or if there is no established
 204  * IUCV path.
 205  * If the IUCV path has been severed, then -EPIPE is returned to cause a
 206  * hang up (that is issued by the HVC console layer).
 207  */
 208 static int hvc_iucv_write(struct hvc_iucv_private *priv,
 209                           char *buf, int count, int *has_more_data)
 210 {
 211         struct iucv_tty_buffer *rb;
 212         int written;
 213         int rc;
 214
 215         /* Immediately return if there is no IUCV connection */
 216         if (priv->iucv_state == IUCV_DISCONN)
 217                 return 0;
 218
 219         /* If the IUCV path has been severed, return -EPIPE to inform the
 220          * hvc console layer to hang up the tty device. */
 221         if (priv->iucv_state == IUCV_SEVERED)
 222                 return -EPIPE;
 223
 224         /* check if there are pending messages */
 225         if (list_empty(&priv->tty_inqueue))
 226                 return 0;
 227
 228         /* receive a iucv message and flip data to the tty (ldisc) */
 229         rb = list_first_entry(&priv->tty_inqueue, struct iucv_tty_buffer, list);
 230
 231         written = 0;
 232         if (!rb->mbuf) { /* message not yet received ... */
 233                 /* allocate mem to store msg data; if no memory is available
 234                  * then leave the buffer on the list and re-try later */
 235                 rb->mbuf = kmalloc(rb->msg.length, GFP_ATOMIC);
 236                 if (!rb->mbuf)
 237                         return -ENOMEM;
 238
 239                 rc = __iucv_message_receive(priv->path, &rb->msg, 0,
 240                                             rb->mbuf, rb->msg.length, NULL);
 241                 switch (rc) {
 242                 case 0: /* Successful       */
 243                         break;
 244                 case 2: /* No message found */
 245                 case 9: /* Message purged   */
 246                         break;
 247                 default:
 248                         written = -EIO;
 249                 }
 250                 /* remove buffer if an error has occured or received data
 251                  * is not correct */
 252                 if (rc || (rb->mbuf->version != MSG_VERSION) ||
 253                           (rb->msg.length    != MSG_SIZE(rb->mbuf->datalen)))
 254                         goto out_remove_buffer;
 255         }
 256
 257         switch (rb->mbuf->type) {
 258         case MSG_TYPE_DATA:
 259                 written = min_t(int, rb->mbuf->datalen - rb->offset, count);
 260                 memcpy(buf, rb->mbuf->data + rb->offset, written);
 261                 if (written < (rb->mbuf->datalen - rb->offset)) {
 262                         rb->offset += written;
 263                         *has_more_data = 1;
 264                         goto out_written;
 265                 }
 266                 break;
 267
 268         case MSG_TYPE_WINSIZE:
 269                 if (rb->mbuf->datalen != sizeof(struct winsize))
 270                         break;
 271                 hvc_resize(priv->hvc, *((struct winsize *)rb->mbuf->data));
 272                 break;
 273
 274         case MSG_TYPE_ERROR:    /* ignored ... */
 275         case MSG_TYPE_TERMENV:  /* ignored ... */
 276         case MSG_TYPE_TERMIOS:  /* ignored ... */
 277                 break;
 278         }
 279
 280 out_remove_buffer:
 281         list_del(&rb->list);
 282         destroy_tty_buffer(rb);
 283         *has_more_data = !list_empty(&priv->tty_inqueue);
 284
 285 out_written:
 286         return written;
 287 }
 288
 289 /**
 290  * hvc_iucv_get_chars() - HVC get_chars operation.
 291  * @vtermno:    HVC virtual terminal number.
 292  * @buf:        Pointer to a buffer to store data
 293  * @count:      Size of buffer available for writing
 294  *
 295  * The hvc_console thread calls this method to read characters from
 296  * the terminal backend. If an IUCV communication path has been established,
 297  * pending IUCV messages are received and data is copied into buffer @buf
 298  * up to @count bytes.
 299  *
 300  * Locking:     The routine gets called under an irqsave() spinlock; and
 301  *              the routine locks the struct hvc_iucv_private->lock to call
 302  *              helper functions.
 303  */
 304 static int hvc_iucv_get_chars(uint32_t vtermno, char *buf, int count)
 305 {
 306         struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 307         int written;
 308         int has_more_data;
 309
 310         if (count <= 0)
 311                 return 0;
 312
 313         if (!priv)
 314                 return -ENODEV;
 315
 316         spin_lock(&priv->lock);
 317         has_more_data = 0;
 318         written = hvc_iucv_write(priv, buf, count, &has_more_data);
 319         spin_unlock(&priv->lock);
 320
 321         /* if there are still messages on the queue... schedule another run */
 322         if (has_more_data)
 323                 hvc_kick();
 324
 325         return written;
 326 }
 327
 328 /**
 329  * hvc_iucv_queue() - Buffer terminal data for sending.
 330  * @priv:       Pointer to struct hvc_iucv_private instance.
 331  * @buf:        Buffer containing data to send.
 332  * @count:      Size of buffer and amount of data to send.
 333  *
 334  * The function queues data for sending. To actually send the buffered data,
 335  * a work queue function is * scheduled (with QUEUE_SNDBUF_DELAY).
 336  * The function returns the number of data bytes that has been buffered.
 337  *
 338  * If the device is not connected, data is ignored and the function returns
 339  * @count.
 340  * If the buffer is full, the function returns 0.
 341  * If an existing IUCV communicaton path has been severed, the function returns
 342  * -EPIPE (can be passed to HVC layer to cause a tty hangup).
 343  */
 344 static int hvc_iucv_queue(struct hvc_iucv_private *priv, const char *buf,
 345                          int count)
 346 {
 347         size_t len;
 348
 349         if (priv->iucv_state == IUCV_DISCONN)
 350                 return count;                   /* ignore data */
 351
 352         if (priv->iucv_state == IUCV_SEVERED)
 353                 return -EPIPE;
 354
 355         len = min_t(size_t, count, SNDBUF_SIZE - priv->sndbuf_len);
 356         if (!len)
 357                 return 0;
 358
 359         memcpy(priv->sndbuf + priv->sndbuf_len, buf, len);
 360         priv->sndbuf_len += len;
 361
 362         if (priv->iucv_state == IUCV_CONNECTED)
 363                 schedule_delayed_work(&priv->sndbuf_work, QUEUE_SNDBUF_DELAY);
 364
 365         return len;
 366 }
 367
 368 /**
 369  * hvc_iucv_send() - Send an IUCV message containing terminal data.
 370  * @priv:       Pointer to struct hvc_iucv_private instance.
 371  *
 372  * If an IUCV communication path has been established, the queued data
 373  * for output are sent via an IUCV message.
 374  *
 375  * If there is no IUCV communication path established, the function returns 0.
 376  * If an existing IUCV communicaton path has been severed, the function returns
 377  * -EPIPE.
 378  */
 379 static int hvc_iucv_send(struct hvc_iucv_private *priv)
 380 {
 381         struct iucv_tty_buffer *sb;
 382         int rc, len;
 383
 384         if (priv->iucv_state == IUCV_SEVERED)
 385                 return -EPIPE;
 386
 387         if (priv->iucv_state == IUCV_DISCONN)
 388                 return -EIO;
 389
 390         if (!priv->sndbuf_len)
 391                 return 0;
 392
 393         /* allocate internal buffer to store msg data and also compute total
 394          * message length */
 395         sb = alloc_tty_buffer(priv->sndbuf_len, GFP_ATOMIC);
 396         if (!sb)
 397                 return -ENOMEM;
 398
 399         memcpy(sb->mbuf->data, priv->sndbuf, priv->sndbuf_len);
 400         sb->mbuf->datalen = (u16) priv->sndbuf_len;
 401         sb->msg.length = MSG_SIZE(sb->mbuf->datalen);
 402
 403         list_add_tail(&sb->list, &priv->tty_outqueue);
 404
 405         rc = __iucv_message_send(priv->path, &sb->msg, 0, 0,
 406                                  (void *) sb->mbuf, sb->msg.length);
 407         if (rc) {
 408                 /* drop the message here; however we might want to handle
 409                  * 0x03 (msg limit reached) by trying again... */
 410                 list_del(&sb->list);
 411                 destroy_tty_buffer(sb);
 412         }
 413         len = priv->sndbuf_len;
 414         priv->sndbuf_len = 0;
 415
 416         return len;
 417 }
 418
 419 /**
 420  * hvc_iucv_sndbuf_work() - Send buffered data over IUCV
 421  * @work:       Work structure.
 422  *
 423  * The function sends buffered output data over IUCV and, if necessary,
 424  * reschedules itself if not all buffered data could be sent.
 425  */
 426 static void hvc_iucv_sndbuf_work(struct work_struct *work)
 427 {
 428         struct hvc_iucv_private *priv;
 429
 430         priv = container_of(work, struct hvc_iucv_private, sndbuf_work.work);
 431
 432         if (!priv)
 433                 return;
 434
 435         spin_lock_bh(&priv->lock);
 436         hvc_iucv_send(priv);
 437         spin_unlock_bh(&priv->lock);
 438 }
 439
 440 /**
 441  * hvc_iucv_put_chars() - HVC put_chars operation.
 442  * @vtermno:    HVC virtual terminal number.
 443  * @buf:        Pointer to an buffer to read data from
 444  * @count:      Size of buffer available for reading
 445  *
 446  * The hvc_console thread calls this method to write characters from
 447  * to the terminal backend.
 448  * The function calls hvc_iucv_send() under the lock of the
 449  * struct hvc_iucv_private instance that corresponds to the tty @vtermno.
 450  *
 451  * Locking:     The method gets called under an irqsave() spinlock; and
 452  *              locks struct hvc_iucv_private->lock.
 453  */
 454 static int hvc_iucv_put_chars(uint32_t vtermno, const char *buf, int count)
 455 {
 456         struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 457         int queued;
 458
 459         if (count <= 0)
 460                 return 0;
 461
 462         if (!priv)
 463                 return -ENODEV;
 464
 465         spin_lock(&priv->lock);
 466         queued = hvc_iucv_queue(priv, buf, count);
 467         spin_unlock(&priv->lock);
 468
 469         return queued;
 470 }
 471
 472 /**
 473  * hvc_iucv_notifier_add() - HVC notifier for opening a TTY for the first time.
 474  * @hp: Pointer to the HVC device (struct hvc_struct)
 475  * @id: Additional data (originally passed to hvc_alloc): the index of an struct
 476  *      hvc_iucv_private instance.
 477  *
 478  * The function sets the tty state to TTY_OPEN for the struct hvc_iucv_private
 479  * instance that is derived from @id. Always returns 0.
 480  *
 481  * Locking:     struct hvc_iucv_private->lock, spin_lock_bh
 482  */
 483 static int hvc_iucv_notifier_add(struct hvc_struct *hp, int id)
 484 {
 485         struct hvc_iucv_private *priv;
 486
 487         priv = hvc_iucv_get_private(id);
 488         if (!priv)
 489                 return 0;
 490
 491         spin_lock_bh(&priv->lock);
 492         priv->tty_state = TTY_OPENED;
 493         spin_unlock_bh(&priv->lock);
 494
 495         return 0;
 496 }
 497
 498 /**
 499  * hvc_iucv_cleanup() - Clean up function if the tty portion is finally closed.
 500  * @priv:       Pointer to the struct hvc_iucv_private instance.
 501  *
 502  * The functions severs the established IUCV communication path (if any), and
 503  * destroy struct iucv_tty_buffer elements from the in- and outqueue. Finally,
 504  * the functions resets the states to TTY_CLOSED and IUCV_DISCONN.
 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);
 553 }
 554
 555 /**
 556  * hvc_iucv_notifier_hangup() - HVC notifier for tty hangups.
 557  * @hp: Pointer to the HVC device (struct hvc_struct)
 558  * @id: Additional data (originally passed to hvc_alloc): the index of an struct
 559  *      hvc_iucv_private instance.
 560  *
 561  * This routine notifies the HVC backend that a tty hangup (carrier loss,
 562  * virtual or otherwise) has occured.
 563  *
 564  * The HVC backend for z/VM IUCV ignores virtual hangups (vhangup()), to keep
 565  * an existing IUCV communication path established.
 566  * (Background: vhangup() is called from user space (by getty or login) to
 567  *              disable writing to the tty by other applications).
 568  *
 569  * If the tty has been opened (e.g. getty) and an established IUCV path has been
 570  * severed (we caused the tty hangup in that case), then the functions invokes
 571  * hvc_iucv_cleanup() to clean up.
 572  *
 573  * Locking:     struct hvc_iucv_private->lock
 574  */
 575 static void hvc_iucv_notifier_hangup(struct hvc_struct *hp, int id)
 576 {
 577         struct hvc_iucv_private *priv;
 578
 579         priv = hvc_iucv_get_private(id);
 580         if (!priv)
 581                 return;
 582
 583         flush_sndbuf_sync(priv);
 584
 585         spin_lock_bh(&priv->lock);
 586         /* NOTE: If the hangup was scheduled by ourself (from the iucv
 587          *       path_servered callback [IUCV_SEVERED]), then we have to
 588          *       finally clean up the tty backend structure and set state to
 589          *       TTY_CLOSED.
 590          *
 591          *       If the tty was hung up otherwise (e.g. vhangup()), then we
 592          *       ignore this hangup and keep an established IUCV path open...
 593          *       (...the reason is that we are not able to connect back to the
 594          *       client if we disconnect on hang up) */
 595         priv->tty_state = TTY_CLOSED;
 596
 597         if (priv->iucv_state == IUCV_SEVERED)
 598                 hvc_iucv_cleanup(priv);
 599         spin_unlock_bh(&priv->lock);
 600 }
 601
 602 /**
 603  * hvc_iucv_notifier_del() - HVC notifier for closing a TTY for the last time.
 604  * @hp:         Pointer to the HVC device (struct hvc_struct)
 605  * @id:         Additional data (originally passed to hvc_alloc):
 606  *              the index of an struct hvc_iucv_private instance.
 607  *
 608  * This routine notifies the HVC backend that the last tty device file
 609  * descriptor has been closed.
 610  * The function calls hvc_iucv_cleanup() to clean up the struct hvc_iucv_private
 611  * instance.
 612  *
 613  * Locking:     struct hvc_iucv_private->lock
 614  */
 615 static void hvc_iucv_notifier_del(struct hvc_struct *hp, int id)
 616 {
 617         struct hvc_iucv_private *priv;
 618         struct iucv_path        *path;
 619
 620         priv = hvc_iucv_get_private(id);
 621         if (!priv)
 622                 return;
 623
 624         flush_sndbuf_sync(priv);
 625
 626         spin_lock_bh(&priv->lock);
 627         path = priv->path;              /* save reference to IUCV path */
 628         priv->path = NULL;
 629         hvc_iucv_cleanup(priv);
 630         spin_unlock_bh(&priv->lock);
 631
 632         /* sever IUCV path outside of priv->lock due to lock ordering of:
 633          * priv->lock <--> iucv_table_lock */
 634         if (path) {
 635                 iucv_path_sever(path, NULL);
 636                 iucv_path_free(path);
 637         }
 638 }
 639
 640 /**
 641  * hvc_iucv_path_pending() - IUCV handler to process a connection request.
 642  * @path:       Pending path (struct iucv_path)
 643  * @ipvmid:     Originator z/VM system identifier
 644  * @ipuser:     User specified data for this path
 645  *              (AF_IUCV: port/service name and originator port)
 646  *
 647  * The function uses the @ipuser data to check to determine if the pending
 648  * path belongs to a terminal managed by this HVC backend.
 649  * If the check is successful, then an additional check is done to ensure
 650  * that a terminal cannot be accessed multiple times (only one connection
 651  * to a terminal is allowed). In that particular case, the pending path is
 652  * severed. If it is the first connection, the pending path is accepted and
 653  * associated to the struct hvc_iucv_private. The iucv state is updated to
 654  * reflect that a communication path has been established.
 655  *
 656  * Returns 0 if the path belongs to a terminal managed by the this HVC backend;
 657  * otherwise returns -ENODEV in order to dispatch this path to other handlers.
 658  *
 659  * Locking:     struct hvc_iucv_private->lock
 660  */
 661 static  int hvc_iucv_path_pending(struct iucv_path *path,
 662                                   u8 ipvmid[8], u8 ipuser[16])
 663 {
 664         struct hvc_iucv_private *priv;
 665         u8 nuser_data[16];
 666         int i, rc;
 667
 668         priv = NULL;
 669         for (i = 0; i < hvc_iucv_devices; i++)
 670                 if (hvc_iucv_table[i] &&
 671                     (0 == memcmp(hvc_iucv_table[i]->srv_name, ipuser, 8))) {
 672                         priv = hvc_iucv_table[i];
 673                         break;
 674                 }
 675
 676         if (!priv)
 677                 return -ENODEV;
 678
 679         spin_lock(&priv->lock);
 680
 681         /* If the terminal is already connected or being severed, then sever
 682          * this path to enforce that there is only ONE established communication
 683          * path per terminal. */
 684         if (priv->iucv_state != IUCV_DISCONN) {
 685                 iucv_path_sever(path, ipuser);
 686                 iucv_path_free(path);
 687                 goto out_path_handled;
 688         }
 689
 690         /* accept path */
 691         memcpy(nuser_data, ipuser + 8, 8);  /* remote service (for af_iucv) */
 692         memcpy(nuser_data + 8, ipuser, 8);  /* local service  (for af_iucv) */
 693         path->msglim = 0xffff;              /* IUCV MSGLIMIT */
 694         path->flags &= ~IUCV_IPRMDATA;      /* TODO: use IUCV_IPRMDATA */
 695         rc = iucv_path_accept(path, &hvc_iucv_handler, nuser_data, priv);
 696         if (rc) {
 697                 iucv_path_sever(path, ipuser);
 698                 iucv_path_free(path);
 699                 goto out_path_handled;
 700         }
 701         priv->path = path;
 702         priv->iucv_state = IUCV_CONNECTED;
 703
 704         /* flush buffered output data... */
 705         schedule_delayed_work(&priv->sndbuf_work, 5);
 706
 707 out_path_handled:
 708         spin_unlock(&priv->lock);
 709         return 0;
 710 }
 711
 712 /**
 713  * hvc_iucv_path_severed() - IUCV handler to process a path sever.
 714  * @path:       Pending path (struct iucv_path)
 715  * @ipuser:     User specified data for this path
 716  *              (AF_IUCV: port/service name and originator port)
 717  *
 718  * The function also severs the path (as required by the IUCV protocol) and
 719  * sets the iucv state to IUCV_SEVERED for the associated struct
 720  * hvc_iucv_private instance. Later, the IUCV_SEVERED state triggers a tty
 721  * hangup (hvc_iucv_get_chars() / hvc_iucv_write()).
 722  *
 723  * If tty portion of the HVC is closed then clean up the outqueue in addition.
 724  *
 725  * Locking:     struct hvc_iucv_private->lock
 726  */
 727 static void hvc_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
 728 {
 729         struct hvc_iucv_private *priv = path->private;
 730
 731         spin_lock(&priv->lock);
 732         priv->iucv_state = IUCV_SEVERED;
 733
 734         /* If the tty has not yet been opened, clean up the hvc_iucv_private
 735          * structure to allow re-connects.
 736          *
 737          * If it has been opened, let get_chars() return -EPIPE to signal the
 738          * HVC layer to hang up the tty.
 739          * If so, we need to wake up the HVC thread to call get_chars()...
 740          */
 741         priv->path = NULL;
 742         if (priv->tty_state == TTY_CLOSED)
 743                 hvc_iucv_cleanup(priv);
 744         else
 745                 hvc_kick();
 746         spin_unlock(&priv->lock);
 747
 748         /* finally sever path (outside of priv->lock due to lock ordering) */
 749         iucv_path_sever(path, ipuser);
 750         iucv_path_free(path);
 751 }
 752
 753 /**
 754  * hvc_iucv_msg_pending() - IUCV handler to process an incoming IUCV message.
 755  * @path:       Pending path (struct iucv_path)
 756  * @msg:        Pointer to the IUCV message
 757  *
 758  * The function stores an incoming message on the input queue for later
 759  * processing (by hvc_iucv_get_chars() / hvc_iucv_write()).
 760  * However, if the tty has not yet been opened, the message is rejected.
 761  *
 762  * Locking:     struct hvc_iucv_private->lock
 763  */
 764 static void hvc_iucv_msg_pending(struct iucv_path *path,
 765                                  struct iucv_message *msg)
 766 {
 767         struct hvc_iucv_private *priv = path->private;
 768         struct iucv_tty_buffer *rb;
 769
 770         /* reject messages that exceed max size of iucv_tty_msg->datalen */
 771         if (msg->length > MSG_SIZE(MSG_MAX_DATALEN)) {
 772                 iucv_message_reject(path, msg);
 773                 return;
 774         }
 775
 776         spin_lock(&priv->lock);
 777
 778         /* reject messages if tty has not yet been opened */
 779         if (priv->tty_state == TTY_CLOSED) {
 780                 iucv_message_reject(path, msg);
 781                 goto unlock_return;
 782         }
 783
 784         /* allocate tty buffer to save iucv msg only */
 785         rb = alloc_tty_buffer(0, GFP_ATOMIC);
 786         if (!rb) {
 787                 iucv_message_reject(path, msg);
 788                 goto unlock_return;     /* -ENOMEM */
 789         }
 790         rb->msg = *msg;
 791
 792         list_add_tail(&rb->list, &priv->tty_inqueue);
 793
 794         hvc_kick();     /* wake up hvc console thread */
 795
 796 unlock_return:
 797         spin_unlock(&priv->lock);
 798 }
 799
 800 /**
 801  * hvc_iucv_msg_complete() - IUCV handler to process message completion
 802  * @path:       Pending path (struct iucv_path)
 803  * @msg:        Pointer to the IUCV message
 804  *
 805  * The function is called upon completion of message delivery and the
 806  * message is removed from the outqueue. Additional delivery information
 807  * can be found in msg->audit: rejected messages (0x040000 (IPADRJCT)) and
 808  * purged messages (0x010000 (IPADPGNR)).
 809  *
 810  * Locking:     struct hvc_iucv_private->lock
 811  */
 812 static void hvc_iucv_msg_complete(struct iucv_path *path,
 813                                   struct iucv_message *msg)
 814 {
 815         struct hvc_iucv_private *priv = path->private;
 816         struct iucv_tty_buffer  *ent, *next;
 817         LIST_HEAD(list_remove);
 818
 819         spin_lock(&priv->lock);
 820         list_for_each_entry_safe(ent, next, &priv->tty_outqueue, list)
 821                 if (ent->msg.id == msg->id) {
 822                         list_move(&ent->list, &list_remove);
 823                         break;
 824                 }
 825         wake_up(&priv->sndbuf_waitq);
 826         spin_unlock(&priv->lock);
 827         destroy_tty_buffer_list(&list_remove);
 828 }
 829
 830
 831 /* HVC operations */
 832 static struct hv_ops hvc_iucv_ops = {
 833         .get_chars = hvc_iucv_get_chars,
 834         .put_chars = hvc_iucv_put_chars,
 835         .notifier_add = hvc_iucv_notifier_add,
 836         .notifier_del = hvc_iucv_notifier_del,
 837         .notifier_hangup = hvc_iucv_notifier_hangup,
 838 };
 839
 840 /**
 841  * hvc_iucv_alloc() - Allocates a new struct hvc_iucv_private instance
 842  * @id: hvc_iucv_table index
 843  *
 844  * This function allocates a new hvc_iucv_private struct and put the
 845  * instance into hvc_iucv_table at index @id.
 846  * Returns 0 on success; otherwise non-zero.
 847  */
 848 static int __init hvc_iucv_alloc(int id)
 849 {
 850         struct hvc_iucv_private *priv;
 851         char name[9];
 852         int rc;
 853
 854         priv = kzalloc(sizeof(struct hvc_iucv_private), GFP_KERNEL);
 855         if (!priv)
 856                 return -ENOMEM;
 857
 858         spin_lock_init(&priv->lock);
 859         INIT_LIST_HEAD(&priv->tty_outqueue);
 860         INIT_LIST_HEAD(&priv->tty_inqueue);
 861         INIT_DELAYED_WORK(&priv->sndbuf_work, hvc_iucv_sndbuf_work);
 862         init_waitqueue_head(&priv->sndbuf_waitq);
 863
 864         priv->sndbuf = (void *) get_zeroed_page(GFP_KERNEL);
 865         if (!priv->sndbuf) {
 866                 kfree(priv);
 867                 return -ENOMEM;
 868         }
 869
 870         /* Finally allocate hvc */
 871         priv->hvc = hvc_alloc(HVC_IUCV_MAGIC + id, /*             PAGE_SIZE */
 872                               HVC_IUCV_MAGIC + id, &hvc_iucv_ops, 256);
 873         if (IS_ERR(priv->hvc)) {
 874                 rc = PTR_ERR(priv->hvc);
 875                 free_page((unsigned long) priv->sndbuf);
 876                 kfree(priv);
 877                 return rc;
 878         }
 879
 880         /* kick khvcd thread; instead of using polling */
 881         priv->hvc->irq_requested = 1;
 882
 883         /* setup iucv related information */
 884         snprintf(name, 9, "lnxhvc%-2d", id);
 885         memcpy(priv->srv_name, name, 8);
 886         ASCEBC(priv->srv_name, 8);
 887
 888         hvc_iucv_table[id] = priv;
 889         return 0;
 890 }
 891
 892 /**
 893  * hvc_iucv_init() - Initialization of HVC backend for z/VM IUCV
 894  */
 895 static int __init hvc_iucv_init(void)
 896 {
 897         int rc, i;
 898
 899         if (!MACHINE_IS_VM) {
 900                 pr_info("The z/VM IUCV HVC device driver cannot "
 901                            "be used without z/VM\n");
 902                 return -ENODEV;
 903         }
 904
 905         if (!hvc_iucv_devices)
 906                 return -ENODEV;
 907
 908         if (hvc_iucv_devices > MAX_HVC_IUCV_LINES)
 909                 return -EINVAL;
 910
 911         hvc_iucv_buffer_cache = kmem_cache_create(KMSG_COMPONENT,
 912                                            sizeof(struct iucv_tty_buffer),
 913                                            0, 0, NULL);
 914         if (!hvc_iucv_buffer_cache) {
 915                 pr_err("Allocating memory failed with reason code=%d\n", 1);
 916                 return -ENOMEM;
 917         }
 918
 919         hvc_iucv_mempool = mempool_create_slab_pool(MEMPOOL_MIN_NR,
 920                                                     hvc_iucv_buffer_cache);
 921         if (!hvc_iucv_mempool) {
 922                 pr_err("Allocating memory failed with reason code=%d\n", 2);
 923                 kmem_cache_destroy(hvc_iucv_buffer_cache);
 924                 return -ENOMEM;
 925         }
 926
 927         /* allocate hvc_iucv_private structs */
 928         for (i = 0; i < hvc_iucv_devices; i++) {
 929                 rc = hvc_iucv_alloc(i);
 930                 if (rc) {
 931                         pr_err("Creating a new HVC terminal device "
 932                                 "failed with error code=%d\n", rc);
 933                         goto out_error_hvc;
 934                 }
 935         }
 936
 937         /* register IUCV callback handler */
 938         rc = iucv_register(&hvc_iucv_handler, 0);
 939         if (rc) {
 940                 pr_err("Registering IUCV handlers failed with error code=%d\n",
 941                         rc);
 942                 goto out_error_iucv;
 943         }
 944
 945         return 0;
 946
 947 out_error_iucv:
 948         iucv_unregister(&hvc_iucv_handler, 0);
 949 out_error_hvc:
 950         for (i = 0; i < hvc_iucv_devices; i++)
 951                 if (hvc_iucv_table[i]) {
 952                         if (hvc_iucv_table[i]->hvc)
 953                                 hvc_remove(hvc_iucv_table[i]->hvc);
 954                         kfree(hvc_iucv_table[i]);
 955                 }
 956         mempool_destroy(hvc_iucv_mempool);
 957         kmem_cache_destroy(hvc_iucv_buffer_cache);
 958         return rc;
 959 }
 960
 961 /**
 962  * hvc_iucv_console_init() - Early console initialization
 963  */
 964 static  int __init hvc_iucv_console_init(void)
 965 {
 966         if (!MACHINE_IS_VM || !hvc_iucv_devices)
 967                 return -ENODEV;
 968         return hvc_instantiate(HVC_IUCV_MAGIC, 0, &hvc_iucv_ops);
 969 }
 970
 971 /**
 972  * hvc_iucv_config() - Parsing of hvc_iucv=  kernel command line parameter
 973  * @val:        Parameter value (numeric)
 974  */
 975 static  int __init hvc_iucv_config(char *val)
 976 {
 977          return strict_strtoul(val, 10, &hvc_iucv_devices);
 978 }
 979
 980
 981 module_init(hvc_iucv_init);
 982 console_initcall(hvc_iucv_console_init);
 983 __setup("hvc_iucv=", hvc_iucv_config);
 984
 985 MODULE_LICENSE("GPL");
 986 MODULE_DESCRIPTION("HVC back-end for z/VM IUCV.");
 987 MODULE_AUTHOR("Hendrik Brueckner <brueckner@linux.vnet.ibm.com>");