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