drivers/tty/hvc/hvc_iucv.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * z/VM IUCV hypervisor console (HVC) device driver
   4  *
   5  * This HVC device driver provides terminal access using
   6  * z/VM IUCV communication paths.
   7  *
   8  * Copyright IBM Corp. 2008, 2013
   9  *
  10  * Author(s):   Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
  11  */
  12 #define KMSG_COMPONENT          "hvc_iucv"
  13 #define pr_fmt(fmt)             KMSG_COMPONENT ": " fmt
  14
  15 #include <linux/types.h>
  16 #include <linux/slab.h>
  17 #include <asm/ebcdic.h>
  18 #include <linux/ctype.h>
  19 #include <linux/delay.h>
  20 #include <linux/device.h>
  21 #include <linux/init.h>
  22 #include <linux/mempool.h>
  23 #include <linux/moduleparam.h>
  24 #include <linux/tty.h>
  25 #include <linux/wait.h>
  26 #include <net/iucv/iucv.h>
  27
  28 #include "hvc_console.h"
  29
  30
  31 /* General device driver settings */
  32 #define HVC_IUCV_MAGIC          0xc9e4c3e5
  33 #define MAX_HVC_IUCV_LINES      HVC_ALLOC_TTY_ADAPTERS
  34 #define MEMPOOL_MIN_NR          (PAGE_SIZE / sizeof(struct iucv_tty_buffer)/4)
  35
  36 /* IUCV TTY message  */
  37 #define MSG_VERSION             0x02    /* Message version */
  38 #define MSG_TYPE_ERROR          0x01    /* Error message */
  39 #define MSG_TYPE_TERMENV        0x02    /* Terminal environment variable */
  40 #define MSG_TYPE_TERMIOS        0x04    /* Terminal IO struct update */
  41 #define MSG_TYPE_WINSIZE        0x08    /* Terminal window size update */
  42 #define MSG_TYPE_DATA           0x10    /* Terminal data */
  43
  44 struct iucv_tty_msg {
  45         u8      version;                /* Message version */
  46         u8      type;                   /* Message type */
  47 #define MSG_MAX_DATALEN         ((u16)(~0))
  48         u16     datalen;                /* Payload length */
  49         u8      data[];                 /* Payload buffer */
  50 } __attribute__((packed));
  51 #define MSG_SIZE(s)             ((s) + offsetof(struct iucv_tty_msg, data))
  52
  53 enum iucv_state_t {
  54         IUCV_DISCONN    = 0,
  55         IUCV_CONNECTED  = 1,
  56         IUCV_SEVERED    = 2,
  57 };
  58
  59 enum tty_state_t {
  60         TTY_CLOSED      = 0,
  61         TTY_OPENED      = 1,
  62 };
  63
  64 struct hvc_iucv_private {
  65         struct hvc_struct       *hvc;           /* HVC struct reference */
  66         u8                      srv_name[8];    /* IUCV service name (ebcdic) */
  67         unsigned char           is_console;     /* Linux console usage flag */
  68         enum iucv_state_t       iucv_state;     /* IUCV connection status */
  69         enum tty_state_t        tty_state;      /* TTY status */
  70         struct iucv_path        *path;          /* IUCV path pointer */
  71         spinlock_t              lock;           /* hvc_iucv_private lock */
  72 #define SNDBUF_SIZE             (PAGE_SIZE)     /* must be < MSG_MAX_DATALEN */
  73         void                    *sndbuf;        /* send buffer            */
  74         size_t                  sndbuf_len;     /* length of send buffer  */
  75 #define QUEUE_SNDBUF_DELAY      (HZ / 25)
  76         struct delayed_work     sndbuf_work;    /* work: send iucv msg(s) */
  77         wait_queue_head_t       sndbuf_waitq;   /* wait for send completion */
  78         struct list_head        tty_outqueue;   /* outgoing IUCV messages */
  79         struct list_head        tty_inqueue;    /* incoming IUCV messages */
  80         struct device           *dev;           /* device structure */
  81         u8                      info_path[16];  /* IUCV path info (dev attr) */
  82 };
  83
  84 struct iucv_tty_buffer {
  85         struct list_head        list;   /* list pointer */
  86         struct iucv_message     msg;    /* store an IUCV message */
  87         size_t                  offset; /* data buffer offset */
  88         struct iucv_tty_msg     *mbuf;  /* buffer to store input/output data */
  89 };
  90
  91 /* IUCV callback handler */
  92 static  int hvc_iucv_path_pending(struct iucv_path *, u8 *, u8 *);
  93 static void hvc_iucv_path_severed(struct iucv_path *, u8 *);
  94 static void hvc_iucv_msg_pending(struct iucv_path *, struct iucv_message *);
  95 static void hvc_iucv_msg_complete(struct iucv_path *, struct iucv_message *);
  96
  97
  98 /* Kernel module parameter: use one terminal device as default */
  99 static unsigned long hvc_iucv_devices = 1;
 100
 101 /* Array of allocated hvc iucv tty lines... */
 102 static struct hvc_iucv_private *hvc_iucv_table[MAX_HVC_IUCV_LINES];
 103 #define IUCV_HVC_CON_IDX        (0)
 104 /* List of z/VM user ID filter entries (struct iucv_vmid_filter) */
 105 #define MAX_VMID_FILTER         (500)
 106 #define FILTER_WILDCARD_CHAR    '*'
 107 static size_t hvc_iucv_filter_size;
 108 static void *hvc_iucv_filter;
 109 static const char *hvc_iucv_filter_string;
 110 static DEFINE_RWLOCK(hvc_iucv_filter_lock);
 111
 112 /* Kmem cache and mempool for iucv_tty_buffer elements */
 113 static struct kmem_cache *hvc_iucv_buffer_cache;
 114 static mempool_t *hvc_iucv_mempool;
 115
 116 /* IUCV handler callback functions */
 117 static struct iucv_handler hvc_iucv_handler = {
 118         .path_pending  = hvc_iucv_path_pending,
 119         .path_severed  = hvc_iucv_path_severed,
 120         .message_complete = hvc_iucv_msg_complete,
 121         .message_pending  = hvc_iucv_msg_pending,
 122 };
 123
 124
 125 /**
 126  * hvc_iucv_get_private() - Return a struct hvc_iucv_private instance.
 127  * @num:        The HVC virtual terminal number (vtermno)
 128  *
 129  * This function returns the struct hvc_iucv_private instance that corresponds
 130  * to the HVC virtual terminal number specified as parameter @num.
 131  */
 132 static struct hvc_iucv_private *hvc_iucv_get_private(uint32_t num)
 133 {
 134         if ((num < HVC_IUCV_MAGIC) || (num - HVC_IUCV_MAGIC > hvc_iucv_devices))
 135                 return NULL;
 136         return hvc_iucv_table[num - HVC_IUCV_MAGIC];
 137 }
 138
 139 /**
 140  * alloc_tty_buffer() - Return a new struct iucv_tty_buffer element.
 141  * @size:       Size of the internal buffer used to store data.
 142  * @flags:      Memory allocation flags passed to mempool.
 143  *
 144  * This function allocates a new struct iucv_tty_buffer element and, optionally,
 145  * allocates an internal data buffer with the specified size @size.
 146  * The internal data buffer is always allocated with GFP_DMA which is
 147  * required for receiving and sending data with IUCV.
 148  * Note: The total message size arises from the internal buffer size and the
 149  *       members of the iucv_tty_msg structure.
 150  * The function returns NULL if memory allocation has failed.
 151  */
 152 static struct iucv_tty_buffer *alloc_tty_buffer(size_t size, gfp_t flags)
 153 {
 154         struct iucv_tty_buffer *bufp;
 155
 156         bufp = mempool_alloc(hvc_iucv_mempool, flags);
 157         if (!bufp)
 158                 return NULL;
 159         memset(bufp, 0, sizeof(*bufp));
 160
 161         if (size > 0) {
 162                 bufp->msg.length = MSG_SIZE(size);
 163                 bufp->mbuf = kmalloc(bufp->msg.length, flags | GFP_DMA);
 164                 if (!bufp->mbuf) {
 165                         mempool_free(bufp, hvc_iucv_mempool);
 166                         return NULL;
 167                 }
 168                 bufp->mbuf->version = MSG_VERSION;
 169                 bufp->mbuf->type    = MSG_TYPE_DATA;
 170                 bufp->mbuf->datalen = (u16) size;
 171         }
 172         return bufp;
 173 }
 174
 175 /**
 176  * destroy_tty_buffer() - destroy struct iucv_tty_buffer element.
 177  * @bufp:       Pointer to a struct iucv_tty_buffer element, SHALL NOT be NULL.
 178  */
 179 static void destroy_tty_buffer(struct iucv_tty_buffer *bufp)
 180 {
 181         kfree(bufp->mbuf);
 182         mempool_free(bufp, hvc_iucv_mempool);
 183 }
 184
 185 /**
 186  * destroy_tty_buffer_list() - call destroy_tty_buffer() for each list element.
 187  * @list:       List containing struct iucv_tty_buffer elements.
 188  */
 189 static void destroy_tty_buffer_list(struct list_head *list)
 190 {
 191         struct iucv_tty_buffer *ent, *next;
 192
 193         list_for_each_entry_safe(ent, next, list, list) {
 194                 list_del(&ent->list);
 195                 destroy_tty_buffer(ent);
 196         }
 197 }
 198
 199 /**
 200  * hvc_iucv_write() - Receive IUCV message & write data to HVC buffer.
 201  * @priv:               Pointer to struct hvc_iucv_private
 202  * @buf:                HVC buffer for writing received terminal data.
 203  * @count:              HVC buffer size.
 204  * @has_more_data:      Pointer to an int variable.
 205  *
 206  * The function picks up pending messages from the input queue and receives
 207  * the message data that is then written to the specified buffer @buf.
 208  * If the buffer size @count is less than the data message size, the
 209  * message is kept on the input queue and @has_more_data is set to 1.
 210  * If all message data has been written, the message is removed from
 211  * the input queue.
 212  *
 213  * The function returns the number of bytes written to the terminal, zero if
 214  * there are no pending data messages available or if there is no established
 215  * IUCV path.
 216  * If the IUCV path has been severed, then -EPIPE is returned to cause a
 217  * hang up (that is issued by the HVC layer).
 218  */
 219 static int hvc_iucv_write(struct hvc_iucv_private *priv,
 220                           char *buf, int count, int *has_more_data)
 221 {
 222         struct iucv_tty_buffer *rb;
 223         int written;
 224         int rc;
 225
 226         /* immediately return if there is no IUCV connection */
 227         if (priv->iucv_state == IUCV_DISCONN)
 228                 return 0;
 229
 230         /* if the IUCV path has been severed, return -EPIPE to inform the
 231          * HVC layer to hang up the tty device. */
 232         if (priv->iucv_state == IUCV_SEVERED)
 233                 return -EPIPE;
 234
 235         /* check if there are pending messages */
 236         if (list_empty(&priv->tty_inqueue))
 237                 return 0;
 238
 239         /* receive an iucv message and flip data to the tty (ldisc) */
 240         rb = list_first_entry(&priv->tty_inqueue, struct iucv_tty_buffer, list);
 241
 242         written = 0;
 243         if (!rb->mbuf) { /* message not yet received ... */
 244                 /* allocate mem to store msg data; if no memory is available
 245                  * then leave the buffer on the list and re-try later */
 246                 rb->mbuf = kmalloc(rb->msg.length, GFP_ATOMIC | GFP_DMA);
 247                 if (!rb->mbuf)
 248                         return -ENOMEM;
 249
 250                 rc = __iucv_message_receive(priv->path, &rb->msg, 0,
 251                                             rb->mbuf, rb->msg.length, NULL);
 252                 switch (rc) {
 253                 case 0: /* Successful       */
 254                         break;
 255                 case 2: /* No message found */
 256                 case 9: /* Message purged   */
 257                         break;
 258                 default:
 259                         written = -EIO;
 260                 }
 261                 /* remove buffer if an error has occurred or received data
 262                  * is not correct */
 263                 if (rc || (rb->mbuf->version != MSG_VERSION) ||
 264                           (rb->msg.length    != MSG_SIZE(rb->mbuf->datalen)))
 265                         goto out_remove_buffer;
 266         }
 267
 268         switch (rb->mbuf->type) {
 269         case MSG_TYPE_DATA:
 270                 written = min_t(int, rb->mbuf->datalen - rb->offset, count);
 271                 memcpy(buf, rb->mbuf->data + rb->offset, written);
 272                 if (written < (rb->mbuf->datalen - rb->offset)) {
 273                         rb->offset += written;
 274                         *has_more_data = 1;
 275                         goto out_written;
 276                 }
 277                 break;
 278
 279         case MSG_TYPE_WINSIZE:
 280                 if (rb->mbuf->datalen != sizeof(struct winsize))
 281                         break;
 282                 /* The caller must ensure that the hvc is locked, which
 283                  * is the case when called from hvc_iucv_get_chars() */
 284                 __hvc_resize(priv->hvc, *((struct winsize *) rb->mbuf->data));
 285                 break;
 286
 287         case MSG_TYPE_ERROR:    /* ignored ... */
 288         case MSG_TYPE_TERMENV:  /* ignored ... */
 289         case MSG_TYPE_TERMIOS:  /* ignored ... */
 290                 break;
 291         }
 292
 293 out_remove_buffer:
 294         list_del(&rb->list);
 295         destroy_tty_buffer(rb);
 296         *has_more_data = !list_empty(&priv->tty_inqueue);
 297
 298 out_written:
 299         return written;
 300 }
 301
 302 /**
 303  * hvc_iucv_get_chars() - HVC get_chars operation.
 304  * @vtermno:    HVC virtual terminal number.
 305  * @buf:        Pointer to a buffer to store data
 306  * @count:      Size of buffer available for writing
 307  *
 308  * The HVC thread calls this method to read characters from the back-end.
 309  * If an IUCV communication path has been established, pending IUCV messages
 310  * are received and data is copied into buffer @buf up to @count bytes.
 311  *
 312  * Locking:     The routine gets called under an irqsave() spinlock; and
 313  *              the routine locks the struct hvc_iucv_private->lock to call
 314  *              helper functions.
 315  */
 316 static int hvc_iucv_get_chars(uint32_t vtermno, char *buf, int count)
 317 {
 318         struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 319         int written;
 320         int has_more_data;
 321
 322         if (count <= 0)
 323                 return 0;
 324
 325         if (!priv)
 326                 return -ENODEV;
 327
 328         spin_lock(&priv->lock);
 329         has_more_data = 0;
 330         written = hvc_iucv_write(priv, buf, count, &has_more_data);
 331         spin_unlock(&priv->lock);
 332
 333         /* if there are still messages on the queue... schedule another run */
 334         if (has_more_data)
 335                 hvc_kick();
 336
 337         return written;
 338 }
 339
 340 /**
 341  * hvc_iucv_queue() - Buffer terminal data for sending.
 342  * @priv:       Pointer to struct hvc_iucv_private instance.
 343  * @buf:        Buffer containing data to send.
 344  * @count:      Size of buffer and amount of data to send.
 345  *
 346  * The function queues data for sending. To actually send the buffered data,
 347  * a work queue function is scheduled (with QUEUE_SNDBUF_DELAY).
 348  * The function returns the number of data bytes that has been buffered.
 349  *
 350  * If the device is not connected, data is ignored and the function returns
 351  * @count.
 352  * If the buffer is full, the function returns 0.
 353  * If an existing IUCV communicaton path has been severed, -EPIPE is returned
 354  * (that can be passed to HVC layer to cause a tty hangup).
 355  */
 356 static int hvc_iucv_queue(struct hvc_iucv_private *priv, const char *buf,
 357                           int count)
 358 {
 359         size_t len;
 360
 361         if (priv->iucv_state == IUCV_DISCONN)
 362                 return count;                   /* ignore data */
 363
 364         if (priv->iucv_state == IUCV_SEVERED)
 365                 return -EPIPE;
 366
 367         len = min_t(size_t, count, SNDBUF_SIZE - priv->sndbuf_len);
 368         if (!len)
 369                 return 0;
 370
 371         memcpy(priv->sndbuf + priv->sndbuf_len, buf, len);
 372         priv->sndbuf_len += len;
 373
 374         if (priv->iucv_state == IUCV_CONNECTED)
 375                 schedule_delayed_work(&priv->sndbuf_work, QUEUE_SNDBUF_DELAY);
 376
 377         return len;
 378 }
 379
 380 /**
 381  * hvc_iucv_send() - Send an IUCV message containing terminal data.
 382  * @priv:       Pointer to struct hvc_iucv_private instance.
 383  *
 384  * If an IUCV communication path has been established, the buffered output data
 385  * is sent via an IUCV message and the number of bytes sent is returned.
 386  * Returns 0 if there is no established IUCV communication path or
 387  * -EPIPE if an existing IUCV communicaton path has been severed.
 388  */
 389 static int hvc_iucv_send(struct hvc_iucv_private *priv)
 390 {
 391         struct iucv_tty_buffer *sb;
 392         int rc, len;
 393
 394         if (priv->iucv_state == IUCV_SEVERED)
 395                 return -EPIPE;
 396
 397         if (priv->iucv_state == IUCV_DISCONN)
 398                 return -EIO;
 399
 400         if (!priv->sndbuf_len)
 401                 return 0;
 402
 403         /* allocate internal buffer to store msg data and also compute total
 404          * message length */
 405         sb = alloc_tty_buffer(priv->sndbuf_len, GFP_ATOMIC);
 406         if (!sb)
 407                 return -ENOMEM;
 408
 409         memcpy(sb->mbuf->data, priv->sndbuf, priv->sndbuf_len);
 410         sb->mbuf->datalen = (u16) priv->sndbuf_len;
 411         sb->msg.length = MSG_SIZE(sb->mbuf->datalen);
 412
 413         list_add_tail(&sb->list, &priv->tty_outqueue);
 414
 415         rc = __iucv_message_send(priv->path, &sb->msg, 0, 0,
 416                                  (void *) sb->mbuf, sb->msg.length);
 417         if (rc) {
 418                 /* drop the message here; however we might want to handle
 419                  * 0x03 (msg limit reached) by trying again... */
 420                 list_del(&sb->list);
 421                 destroy_tty_buffer(sb);
 422         }
 423         len = priv->sndbuf_len;
 424         priv->sndbuf_len = 0;
 425
 426         return len;
 427 }
 428
 429 /**
 430  * hvc_iucv_sndbuf_work() - Send buffered data over IUCV
 431  * @work:       Work structure.
 432  *
 433  * This work queue function sends buffered output data over IUCV and,
 434  * if not all buffered data could be sent, reschedules itself.
 435  */
 436 static void hvc_iucv_sndbuf_work(struct work_struct *work)
 437 {
 438         struct hvc_iucv_private *priv;
 439
 440         priv = container_of(work, struct hvc_iucv_private, sndbuf_work.work);
 441         if (!priv)
 442                 return;
 443
 444         spin_lock_bh(&priv->lock);
 445         hvc_iucv_send(priv);
 446         spin_unlock_bh(&priv->lock);
 447 }
 448
 449 /**
 450  * hvc_iucv_put_chars() - HVC put_chars operation.
 451  * @vtermno:    HVC virtual terminal number.
 452  * @buf:        Pointer to an buffer to read data from
 453  * @count:      Size of buffer available for reading
 454  *
 455  * The HVC thread calls this method to write characters to the back-end.
 456  * The function calls hvc_iucv_queue() to queue terminal data for sending.
 457  *
 458  * Locking:     The method gets called under an irqsave() spinlock; and
 459  *              locks struct hvc_iucv_private->lock.
 460  */
 461 static int hvc_iucv_put_chars(uint32_t vtermno, const char *buf, int count)
 462 {
 463         struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 464         int queued;
 465
 466         if (count <= 0)
 467                 return 0;
 468
 469         if (!priv)
 470                 return -ENODEV;
 471
 472         spin_lock(&priv->lock);
 473         queued = hvc_iucv_queue(priv, buf, count);
 474         spin_unlock(&priv->lock);
 475
 476         return queued;
 477 }
 478
 479 /**
 480  * hvc_iucv_notifier_add() - HVC notifier for opening a TTY for the first time.
 481  * @hp: Pointer to the HVC device (struct hvc_struct)
 482  * @id: Additional data (originally passed to hvc_alloc): the index of an struct
 483  *      hvc_iucv_private instance.
 484  *
 485  * The function sets the tty state to TTY_OPENED for the struct hvc_iucv_private
 486  * instance that is derived from @id. Always returns 0.
 487  *
 488  * Locking:     struct hvc_iucv_private->lock, spin_lock_bh
 489  */
 490 static int hvc_iucv_notifier_add(struct hvc_struct *hp, int id)
 491 {
 492         struct hvc_iucv_private *priv;
 493
 494         priv = hvc_iucv_get_private(id);
 495         if (!priv)
 496                 return 0;
 497
 498         spin_lock_bh(&priv->lock);
 499         priv->tty_state = TTY_OPENED;
 500         spin_unlock_bh(&priv->lock);
 501
 502         return 0;
 503 }
 504
 505 /**
 506  * hvc_iucv_cleanup() - Clean up and reset a z/VM IUCV HVC instance.
 507  * @priv:       Pointer to the struct hvc_iucv_private instance.
 508  */
 509 static void hvc_iucv_cleanup(struct hvc_iucv_private *priv)
 510 {
 511         destroy_tty_buffer_list(&priv->tty_outqueue);
 512         destroy_tty_buffer_list(&priv->tty_inqueue);
 513
 514         priv->tty_state = TTY_CLOSED;
 515         priv->iucv_state = IUCV_DISCONN;
 516
 517         priv->sndbuf_len = 0;
 518 }
 519
 520 /**
 521  * tty_outqueue_empty() - Test if the tty outq is empty
 522  * @priv:       Pointer to struct hvc_iucv_private instance.
 523  */
 524 static inline int tty_outqueue_empty(struct hvc_iucv_private *priv)
 525 {
 526         int rc;
 527
 528         spin_lock_bh(&priv->lock);
 529         rc = list_empty(&priv->tty_outqueue);
 530         spin_unlock_bh(&priv->lock);
 531
 532         return rc;
 533 }
 534
 535 /**
 536  * flush_sndbuf_sync() - Flush send buffer and wait for completion
 537  * @priv:       Pointer to struct hvc_iucv_private instance.
 538  *
 539  * The routine cancels a pending sndbuf work, calls hvc_iucv_send()
 540  * to flush any buffered terminal output data and waits for completion.
 541  */
 542 static void flush_sndbuf_sync(struct hvc_iucv_private *priv)
 543 {
 544         int sync_wait;
 545
 546         cancel_delayed_work_sync(&priv->sndbuf_work);
 547
 548         spin_lock_bh(&priv->lock);
 549         hvc_iucv_send(priv);            /* force sending buffered data */
 550         sync_wait = !list_empty(&priv->tty_outqueue); /* anything queued ? */
 551         spin_unlock_bh(&priv->lock);
 552
 553         if (sync_wait)
 554                 wait_event_timeout(priv->sndbuf_waitq,
 555                                    tty_outqueue_empty(priv), HZ/10);
 556 }
 557
 558 /**
 559  * hvc_iucv_hangup() - Sever IUCV path and schedule hvc tty hang up
 560  * @priv:       Pointer to hvc_iucv_private structure
 561  *
 562  * This routine severs an existing IUCV communication path and hangs
 563  * up the underlying HVC terminal device.
 564  * The hang-up occurs only if an IUCV communication path is established;
 565  * otherwise there is no need to hang up the terminal device.
 566  *
 567  * The IUCV HVC hang-up is separated into two steps:
 568  * 1. After the IUCV path has been severed, the iucv_state is set to
 569  *    IUCV_SEVERED.
 570  * 2. Later, when the HVC thread calls hvc_iucv_get_chars(), the
 571  *    IUCV_SEVERED state causes the tty hang-up in the HVC layer.
 572  *
 573  * If the tty has not yet been opened, clean up the hvc_iucv_private
 574  * structure to allow re-connects.
 575  * If the tty has been opened, let get_chars() return -EPIPE to signal
 576  * the HVC layer to hang up the tty and, if so, wake up the HVC thread
 577  * to call get_chars()...
 578  *
 579  * Special notes on hanging up a HVC terminal instantiated as console:
 580  * Hang-up:     1. do_tty_hangup() replaces file ops (= hung_up_tty_fops)
 581  *              2. do_tty_hangup() calls tty->ops->close() for console_filp
 582  *                      => no hangup notifier is called by HVC (default)
 583  *              2. hvc_close() returns because of tty_hung_up_p(filp)
 584  *                      => no delete notifier is called!
 585  * Finally, the back-end is not being notified, thus, the tty session is
 586  * kept active (TTY_OPEN) to be ready for re-connects.
 587  *
 588  * Locking:     spin_lock(&priv->lock) w/o disabling bh
 589  */
 590 static void hvc_iucv_hangup(struct hvc_iucv_private *priv)
 591 {
 592         struct iucv_path *path;
 593
 594         path = NULL;
 595         spin_lock(&priv->lock);
 596         if (priv->iucv_state == IUCV_CONNECTED) {
 597                 path = priv->path;
 598                 priv->path = NULL;
 599                 priv->iucv_state = IUCV_SEVERED;
 600                 if (priv->tty_state == TTY_CLOSED)
 601                         hvc_iucv_cleanup(priv);
 602                 else
 603                         /* console is special (see above) */
 604                         if (priv->is_console) {
 605                                 hvc_iucv_cleanup(priv);
 606                                 priv->tty_state = TTY_OPENED;
 607                         } else
 608                                 hvc_kick();
 609         }
 610         spin_unlock(&priv->lock);
 611
 612         /* finally sever path (outside of priv->lock due to lock ordering) */
 613         if (path) {
 614                 iucv_path_sever(path, NULL);
 615                 iucv_path_free(path);
 616         }
 617 }
 618
 619 /**
 620  * hvc_iucv_notifier_hangup() - HVC notifier for TTY hangups.
 621  * @hp:         Pointer to the HVC device (struct hvc_struct)
 622  * @id:         Additional data (originally passed to hvc_alloc):
 623  *              the index of an struct hvc_iucv_private instance.
 624  *
 625  * This routine notifies the HVC back-end that a tty hangup (carrier loss,
 626  * virtual or otherwise) has occurred.
 627  * The z/VM IUCV HVC device driver ignores virtual hangups (vhangup())
 628  * to keep an existing IUCV communication path established.
 629  * (Background: vhangup() is called from user space (by getty or login) to
 630  *              disable writing to the tty by other applications).
 631  * If the tty has been opened and an established IUCV path has been severed
 632  * (we caused the tty hangup), the function calls hvc_iucv_cleanup().
 633  *
 634  * Locking:     struct hvc_iucv_private->lock
 635  */
 636 static void hvc_iucv_notifier_hangup(struct hvc_struct *hp, int id)
 637 {
 638         struct hvc_iucv_private *priv;
 639
 640         priv = hvc_iucv_get_private(id);
 641         if (!priv)
 642                 return;
 643
 644         flush_sndbuf_sync(priv);
 645
 646         spin_lock_bh(&priv->lock);
 647         /* NOTE: If the hangup was scheduled by ourself (from the iucv
 648          *       path_servered callback [IUCV_SEVERED]), we have to clean up
 649          *       our structure and to set state to TTY_CLOSED.
 650          *       If the tty was hung up otherwise (e.g. vhangup()), then we
 651          *       ignore this hangup and keep an established IUCV path open...
 652          *       (...the reason is that we are not able to connect back to the
 653          *       client if we disconnect on hang up) */
 654         priv->tty_state = TTY_CLOSED;
 655
 656         if (priv->iucv_state == IUCV_SEVERED)
 657                 hvc_iucv_cleanup(priv);
 658         spin_unlock_bh(&priv->lock);
 659 }
 660
 661 /**
 662  * hvc_iucv_dtr_rts() - HVC notifier for handling DTR/RTS
 663  * @hp:         Pointer the HVC device (struct hvc_struct)
 664  * @raise:      Non-zero to raise or zero to lower DTR/RTS lines
 665  *
 666  * This routine notifies the HVC back-end to raise or lower DTR/RTS
 667  * lines.  Raising DTR/RTS is ignored.  Lowering DTR/RTS indicates to
 668  * drop the IUCV connection (similar to hang up the modem).
 669  */
 670 static void hvc_iucv_dtr_rts(struct hvc_struct *hp, int raise)
 671 {
 672         struct hvc_iucv_private *priv;
 673         struct iucv_path        *path;
 674
 675         /* Raising the DTR/RTS is ignored as IUCV connections can be
 676          * established at any times.
 677          */
 678         if (raise)
 679                 return;
 680
 681         priv = hvc_iucv_get_private(hp->vtermno);
 682         if (!priv)
 683                 return;
 684
 685         /* Lowering the DTR/RTS lines disconnects an established IUCV
 686          * connection.
 687          */
 688         flush_sndbuf_sync(priv);
 689
 690         spin_lock_bh(&priv->lock);
 691         path = priv->path;              /* save reference to IUCV path */
 692         priv->path = NULL;
 693         priv->iucv_state = IUCV_DISCONN;
 694         spin_unlock_bh(&priv->lock);
 695
 696         /* Sever IUCV path outside of priv->lock due to lock ordering of:
 697          * priv->lock <--> iucv_table_lock */
 698         if (path) {
 699                 iucv_path_sever(path, NULL);
 700                 iucv_path_free(path);
 701         }
 702 }
 703
 704 /**
 705  * hvc_iucv_notifier_del() - HVC notifier for closing a TTY for the last time.
 706  * @hp:         Pointer to the HVC device (struct hvc_struct)
 707  * @id:         Additional data (originally passed to hvc_alloc):
 708  *              the index of an struct hvc_iucv_private instance.
 709  *
 710  * This routine notifies the HVC back-end that the last tty device fd has been
 711  * closed.  The function cleans up tty resources.  The clean-up of the IUCV
 712  * connection is done in hvc_iucv_dtr_rts() and depends on the HUPCL termios
 713  * control setting.
 714  *
 715  * Locking:     struct hvc_iucv_private->lock
 716  */
 717 static void hvc_iucv_notifier_del(struct hvc_struct *hp, int id)
 718 {
 719         struct hvc_iucv_private *priv;
 720
 721         priv = hvc_iucv_get_private(id);
 722         if (!priv)
 723                 return;
 724
 725         flush_sndbuf_sync(priv);
 726
 727         spin_lock_bh(&priv->lock);
 728         destroy_tty_buffer_list(&priv->tty_outqueue);
 729         destroy_tty_buffer_list(&priv->tty_inqueue);
 730         priv->tty_state = TTY_CLOSED;
 731         priv->sndbuf_len = 0;
 732         spin_unlock_bh(&priv->lock);
 733 }
 734
 735 /**
 736  * hvc_iucv_filter_connreq() - Filter connection request based on z/VM user ID
 737  * @ipvmid:     Originating z/VM user ID (right padded with blanks)
 738  *
 739  * Returns 0 if the z/VM user ID that is specified with @ipvmid is permitted to
 740  * connect, otherwise non-zero.
 741  */
 742 static int hvc_iucv_filter_connreq(u8 ipvmid[8])
 743 {
 744         const char *wildcard, *filter_entry;
 745         size_t i, len;
 746
 747         /* Note: default policy is ACCEPT if no filter is set */
 748         if (!hvc_iucv_filter_size)
 749                 return 0;
 750
 751         for (i = 0; i < hvc_iucv_filter_size; i++) {
 752                 filter_entry = hvc_iucv_filter + (8 * i);
 753
 754                 /* If a filter entry contains the filter wildcard character,
 755                  * reduce the length to match the leading portion of the user
 756                  * ID only (wildcard match).  Characters following the wildcard
 757                  * are ignored.
 758                  */
 759                 wildcard = strnchr(filter_entry, 8, FILTER_WILDCARD_CHAR);
 760                 len = (wildcard) ? wildcard - filter_entry : 8;
 761                 if (0 == memcmp(ipvmid, filter_entry, len))
 762                         return 0;
 763         }
 764         return 1;
 765 }
 766
 767 /**
 768  * hvc_iucv_path_pending() - IUCV handler to process a connection request.
 769  * @path:       Pending path (struct iucv_path)
 770  * @ipvmid:     z/VM system identifier of originator
 771  * @ipuser:     User specified data for this path
 772  *              (AF_IUCV: port/service name and originator port)
 773  *
 774  * The function uses the @ipuser data to determine if the pending path belongs
 775  * to a terminal managed by this device driver.
 776  * If the path belongs to this driver, ensure that the terminal is not accessed
 777  * multiple times (only one connection to a terminal is allowed).
 778  * If the terminal is not yet connected, the pending path is accepted and is
 779  * associated to the appropriate struct hvc_iucv_private instance.
 780  *
 781  * Returns 0 if @path belongs to a terminal managed by the this device driver;
 782  * otherwise returns -ENODEV in order to dispatch this path to other handlers.
 783  *
 784  * Locking:     struct hvc_iucv_private->lock
 785  */
 786 static  int hvc_iucv_path_pending(struct iucv_path *path, u8 *ipvmid,
 787                                   u8 *ipuser)
 788 {
 789         struct hvc_iucv_private *priv, *tmp;
 790         u8 wildcard[9] = "lnxhvc  ";
 791         int i, rc, find_unused;
 792         u8 nuser_data[16];
 793         u8 vm_user_id[9];
 794
 795         ASCEBC(wildcard, sizeof(wildcard));
 796         find_unused = !memcmp(wildcard, ipuser, 8);
 797
 798         /* First, check if the pending path request is managed by this
 799          * IUCV handler:
 800          * - find a disconnected device if ipuser contains the wildcard
 801          * - find the device that matches the terminal ID in ipuser
 802          */
 803         priv = NULL;
 804         for (i = 0; i < hvc_iucv_devices; i++) {
 805                 tmp = hvc_iucv_table[i];
 806                 if (!tmp)
 807                         continue;
 808
 809                 if (find_unused) {
 810                         spin_lock(&tmp->lock);
 811                         if (tmp->iucv_state == IUCV_DISCONN)
 812                                 priv = tmp;
 813                         spin_unlock(&tmp->lock);
 814
 815                 } else if (!memcmp(tmp->srv_name, ipuser, 8))
 816                                 priv = tmp;
 817                 if (priv)
 818                         break;
 819         }
 820         if (!priv)
 821                 return -ENODEV;
 822
 823         /* Enforce that ipvmid is allowed to connect to us */
 824         read_lock(&hvc_iucv_filter_lock);
 825         rc = hvc_iucv_filter_connreq(ipvmid);
 826         read_unlock(&hvc_iucv_filter_lock);
 827         if (rc) {
 828                 iucv_path_sever(path, ipuser);
 829                 iucv_path_free(path);
 830                 memcpy(vm_user_id, ipvmid, 8);
 831                 vm_user_id[8] = 0;
 832                 pr_info("A connection request from z/VM user ID %s "
 833                         "was refused\n", vm_user_id);
 834                 return 0;
 835         }
 836
 837         spin_lock(&priv->lock);
 838
 839         /* If the terminal is already connected or being severed, then sever
 840          * this path to enforce that there is only ONE established communication
 841          * path per terminal. */
 842         if (priv->iucv_state != IUCV_DISCONN) {
 843                 iucv_path_sever(path, ipuser);
 844                 iucv_path_free(path);
 845                 goto out_path_handled;
 846         }
 847
 848         /* accept path */
 849         memcpy(nuser_data, ipuser + 8, 8);  /* remote service (for af_iucv) */
 850         memcpy(nuser_data + 8, ipuser, 8);  /* local service  (for af_iucv) */
 851         path->msglim = 0xffff;              /* IUCV MSGLIMIT */
 852         path->flags &= ~IUCV_IPRMDATA;      /* TODO: use IUCV_IPRMDATA */
 853         rc = iucv_path_accept(path, &hvc_iucv_handler, nuser_data, priv);
 854         if (rc) {
 855                 iucv_path_sever(path, ipuser);
 856                 iucv_path_free(path);
 857                 goto out_path_handled;
 858         }
 859         priv->path = path;
 860         priv->iucv_state = IUCV_CONNECTED;
 861
 862         /* store path information */
 863         memcpy(priv->info_path, ipvmid, 8);
 864         memcpy(priv->info_path + 8, ipuser + 8, 8);
 865
 866         /* flush buffered output data... */
 867         schedule_delayed_work(&priv->sndbuf_work, 5);
 868
 869 out_path_handled:
 870         spin_unlock(&priv->lock);
 871         return 0;
 872 }
 873
 874 /**
 875  * hvc_iucv_path_severed() - IUCV handler to process a path sever.
 876  * @path:       Pending path (struct iucv_path)
 877  * @ipuser:     User specified data for this path
 878  *              (AF_IUCV: port/service name and originator port)
 879  *
 880  * This function calls the hvc_iucv_hangup() function for the
 881  * respective IUCV HVC terminal.
 882  *
 883  * Locking:     struct hvc_iucv_private->lock
 884  */
 885 static void hvc_iucv_path_severed(struct iucv_path *path, u8 *ipuser)
 886 {
 887         struct hvc_iucv_private *priv = path->private;
 888
 889         hvc_iucv_hangup(priv);
 890 }
 891
 892 /**
 893  * hvc_iucv_msg_pending() - IUCV handler to process an incoming IUCV message.
 894  * @path:       Pending path (struct iucv_path)
 895  * @msg:        Pointer to the IUCV message
 896  *
 897  * The function puts an incoming message on the input queue for later
 898  * processing (by hvc_iucv_get_chars() / hvc_iucv_write()).
 899  * If the tty has not yet been opened, the message is rejected.
 900  *
 901  * Locking:     struct hvc_iucv_private->lock
 902  */
 903 static void hvc_iucv_msg_pending(struct iucv_path *path,
 904                                  struct iucv_message *msg)
 905 {
 906         struct hvc_iucv_private *priv = path->private;
 907         struct iucv_tty_buffer *rb;
 908
 909         /* reject messages that exceed max size of iucv_tty_msg->datalen */
 910         if (msg->length > MSG_SIZE(MSG_MAX_DATALEN)) {
 911                 iucv_message_reject(path, msg);
 912                 return;
 913         }
 914
 915         spin_lock(&priv->lock);
 916
 917         /* reject messages if tty has not yet been opened */
 918         if (priv->tty_state == TTY_CLOSED) {
 919                 iucv_message_reject(path, msg);
 920                 goto unlock_return;
 921         }
 922
 923         /* allocate tty buffer to save iucv msg only */
 924         rb = alloc_tty_buffer(0, GFP_ATOMIC);
 925         if (!rb) {
 926                 iucv_message_reject(path, msg);
 927                 goto unlock_return;     /* -ENOMEM */
 928         }
 929         rb->msg = *msg;
 930
 931         list_add_tail(&rb->list, &priv->tty_inqueue);
 932
 933         hvc_kick();     /* wake up hvc thread */
 934
 935 unlock_return:
 936         spin_unlock(&priv->lock);
 937 }
 938
 939 /**
 940  * hvc_iucv_msg_complete() - IUCV handler to process message completion
 941  * @path:       Pending path (struct iucv_path)
 942  * @msg:        Pointer to the IUCV message
 943  *
 944  * The function is called upon completion of message delivery to remove the
 945  * message from the outqueue. Additional delivery information can be found
 946  * msg->audit: rejected messages (0x040000 (IPADRJCT)), and
 947  *             purged messages   (0x010000 (IPADPGNR)).
 948  *
 949  * Locking:     struct hvc_iucv_private->lock
 950  */
 951 static void hvc_iucv_msg_complete(struct iucv_path *path,
 952                                   struct iucv_message *msg)
 953 {
 954         struct hvc_iucv_private *priv = path->private;
 955         struct iucv_tty_buffer  *ent, *next;
 956         LIST_HEAD(list_remove);
 957
 958         spin_lock(&priv->lock);
 959         list_for_each_entry_safe(ent, next, &priv->tty_outqueue, list)
 960                 if (ent->msg.id == msg->id) {
 961                         list_move(&ent->list, &list_remove);
 962                         break;
 963                 }
 964         wake_up(&priv->sndbuf_waitq);
 965         spin_unlock(&priv->lock);
 966         destroy_tty_buffer_list(&list_remove);
 967 }
 968
 969 /**
 970  * hvc_iucv_pm_freeze() - Freeze PM callback
 971  * @dev:        IUVC HVC terminal device
 972  *
 973  * Sever an established IUCV communication path and
 974  * trigger a hang-up of the underlying HVC terminal.
 975  */
 976 static int hvc_iucv_pm_freeze(struct device *dev)
 977 {
 978         struct hvc_iucv_private *priv = dev_get_drvdata(dev);
 979
 980         local_bh_disable();
 981         hvc_iucv_hangup(priv);
 982         local_bh_enable();
 983
 984         return 0;
 985 }
 986
 987 /**
 988  * hvc_iucv_pm_restore_thaw() - Thaw and restore PM callback
 989  * @dev:        IUVC HVC terminal device
 990  *
 991  * Wake up the HVC thread to trigger hang-up and respective
 992  * HVC back-end notifier invocations.
 993  */
 994 static int hvc_iucv_pm_restore_thaw(struct device *dev)
 995 {
 996         hvc_kick();
 997         return 0;
 998 }
 999
1000 static ssize_t hvc_iucv_dev_termid_show(struct device *dev,
1001                                         struct device_attribute *attr,
1002                                         char *buf)
1003 {
1004         struct hvc_iucv_private *priv = dev_get_drvdata(dev);
1005         size_t len;
1006
1007         len = sizeof(priv->srv_name);
1008         memcpy(buf, priv->srv_name, len);
1009         EBCASC(buf, len);
1010         buf[len++] = '\n';
1011         return len;
1012 }
1013
1014 static ssize_t hvc_iucv_dev_state_show(struct device *dev,
1015                                         struct device_attribute *attr,
1016                                         char *buf)
1017 {
1018         struct hvc_iucv_private *priv = dev_get_drvdata(dev);
1019         return sprintf(buf, "%u:%u\n", priv->iucv_state, priv->tty_state);
1020 }
1021
1022 static ssize_t hvc_iucv_dev_peer_show(struct device *dev,
1023                                       struct device_attribute *attr,
1024                                       char *buf)
1025 {
1026         struct hvc_iucv_private *priv = dev_get_drvdata(dev);
1027         char vmid[9], ipuser[9];
1028
1029         memset(vmid, 0, sizeof(vmid));
1030         memset(ipuser, 0, sizeof(ipuser));
1031
1032         spin_lock_bh(&priv->lock);
1033         if (priv->iucv_state == IUCV_CONNECTED) {
1034                 memcpy(vmid, priv->info_path, 8);
1035                 memcpy(ipuser, priv->info_path + 8, 8);
1036         }
1037         spin_unlock_bh(&priv->lock);
1038         EBCASC(ipuser, 8);
1039
1040         return sprintf(buf, "%s:%s\n", vmid, ipuser);
1041 }
1042
1043
1044 /* HVC operations */
1045 static const struct hv_ops hvc_iucv_ops = {
1046         .get_chars = hvc_iucv_get_chars,
1047         .put_chars = hvc_iucv_put_chars,
1048         .notifier_add = hvc_iucv_notifier_add,
1049         .notifier_del = hvc_iucv_notifier_del,
1050         .notifier_hangup = hvc_iucv_notifier_hangup,
1051         .dtr_rts = hvc_iucv_dtr_rts,
1052 };
1053
1054 /* Suspend / resume device operations */
1055 static const struct dev_pm_ops hvc_iucv_pm_ops = {
1056         .freeze   = hvc_iucv_pm_freeze,
1057         .thaw     = hvc_iucv_pm_restore_thaw,
1058         .restore  = hvc_iucv_pm_restore_thaw,
1059 };
1060
1061 /* IUCV HVC device driver */
1062 static struct device_driver hvc_iucv_driver = {
1063         .name = KMSG_COMPONENT,
1064         .bus  = &iucv_bus,
1065         .pm   = &hvc_iucv_pm_ops,
1066 };
1067
1068 /* IUCV HVC device attributes */
1069 static DEVICE_ATTR(termid, 0640, hvc_iucv_dev_termid_show, NULL);
1070 static DEVICE_ATTR(state, 0640, hvc_iucv_dev_state_show, NULL);
1071 static DEVICE_ATTR(peer, 0640, hvc_iucv_dev_peer_show, NULL);
1072 static struct attribute *hvc_iucv_dev_attrs[] = {
1073         &dev_attr_termid.attr,
1074         &dev_attr_state.attr,
1075         &dev_attr_peer.attr,
1076         NULL,
1077 };
1078 static struct attribute_group hvc_iucv_dev_attr_group = {
1079         .attrs = hvc_iucv_dev_attrs,
1080 };
1081 static const struct attribute_group *hvc_iucv_dev_attr_groups[] = {
1082         &hvc_iucv_dev_attr_group,
1083         NULL,
1084 };
1085
1086
1087 /**
1088  * hvc_iucv_alloc() - Allocates a new struct hvc_iucv_private instance
1089  * @id:                 hvc_iucv_table index
1090  * @is_console:         Flag if the instance is used as Linux console
1091  *
1092  * This function allocates a new hvc_iucv_private structure and stores
1093  * the instance in hvc_iucv_table at index @id.
1094  * Returns 0 on success; otherwise non-zero.
1095  */
1096 static int __init hvc_iucv_alloc(int id, unsigned int is_console)
1097 {
1098         struct hvc_iucv_private *priv;
1099         char name[9];
1100         int rc;
1101
1102         priv = kzalloc(sizeof(struct hvc_iucv_private), GFP_KERNEL);
1103         if (!priv)
1104                 return -ENOMEM;
1105
1106         spin_lock_init(&priv->lock);
1107         INIT_LIST_HEAD(&priv->tty_outqueue);
1108         INIT_LIST_HEAD(&priv->tty_inqueue);
1109         INIT_DELAYED_WORK(&priv->sndbuf_work, hvc_iucv_sndbuf_work);
1110         init_waitqueue_head(&priv->sndbuf_waitq);
1111
1112         priv->sndbuf = (void *) get_zeroed_page(GFP_KERNEL);
1113         if (!priv->sndbuf) {
1114                 kfree(priv);
1115                 return -ENOMEM;
1116         }
1117
1118         /* set console flag */
1119         priv->is_console = is_console;
1120
1121         /* allocate hvc device */
1122         priv->hvc = hvc_alloc(HVC_IUCV_MAGIC + id, /*             PAGE_SIZE */
1123                               HVC_IUCV_MAGIC + id, &hvc_iucv_ops, 256);
1124         if (IS_ERR(priv->hvc)) {
1125                 rc = PTR_ERR(priv->hvc);
1126                 goto out_error_hvc;
1127         }
1128
1129         /* notify HVC thread instead of using polling */
1130         priv->hvc->irq_requested = 1;
1131
1132         /* setup iucv related information */
1133         snprintf(name, 9, "lnxhvc%-2d", id);
1134         memcpy(priv->srv_name, name, 8);
1135         ASCEBC(priv->srv_name, 8);
1136
1137         /* create and setup device */
1138         priv->dev = kzalloc(sizeof(*priv->dev), GFP_KERNEL);
1139         if (!priv->dev) {
1140                 rc = -ENOMEM;
1141                 goto out_error_dev;
1142         }
1143         dev_set_name(priv->dev, "hvc_iucv%d", id);
1144         dev_set_drvdata(priv->dev, priv);
1145         priv->dev->bus = &iucv_bus;
1146         priv->dev->parent = iucv_root;
1147         priv->dev->driver = &hvc_iucv_driver;
1148         priv->dev->groups = hvc_iucv_dev_attr_groups;
1149         priv->dev->release = (void (*)(struct device *)) kfree;
1150         rc = device_register(priv->dev);
1151         if (rc) {
1152                 put_device(priv->dev);
1153                 goto out_error_dev;
1154         }
1155
1156         hvc_iucv_table[id] = priv;
1157         return 0;
1158
1159 out_error_dev:
1160         hvc_remove(priv->hvc);
1161 out_error_hvc:
1162         free_page((unsigned long) priv->sndbuf);
1163         kfree(priv);
1164
1165         return rc;
1166 }
1167
1168 /**
1169  * hvc_iucv_destroy() - Destroy and free hvc_iucv_private instances
1170  */
1171 static void __init hvc_iucv_destroy(struct hvc_iucv_private *priv)
1172 {
1173         hvc_remove(priv->hvc);
1174         device_unregister(priv->dev);
1175         free_page((unsigned long) priv->sndbuf);
1176         kfree(priv);
1177 }
1178
1179 /**
1180  * hvc_iucv_parse_filter() - Parse filter for a single z/VM user ID
1181  * @filter:     String containing a comma-separated list of z/VM user IDs
1182  * @dest:       Location where to store the parsed z/VM user ID
1183  */
1184 static const char *hvc_iucv_parse_filter(const char *filter, char *dest)
1185 {
1186         const char *nextdelim, *residual;
1187         size_t len;
1188
1189         nextdelim = strchr(filter, ',');
1190         if (nextdelim) {
1191                 len = nextdelim - filter;
1192                 residual = nextdelim + 1;
1193         } else {
1194                 len = strlen(filter);
1195                 residual = filter + len;
1196         }
1197
1198         if (len == 0)
1199                 return ERR_PTR(-EINVAL);
1200
1201         /* check for '\n' (if called from sysfs) */
1202         if (filter[len - 1] == '\n')
1203                 len--;
1204
1205         /* prohibit filter entries containing the wildcard character only */
1206         if (len == 1 && *filter == FILTER_WILDCARD_CHAR)
1207                 return ERR_PTR(-EINVAL);
1208
1209         if (len > 8)
1210                 return ERR_PTR(-EINVAL);
1211
1212         /* pad with blanks and save upper case version of user ID */
1213         memset(dest, ' ', 8);
1214         while (len--)
1215                 dest[len] = toupper(filter[len]);
1216         return residual;
1217 }
1218
1219 /**
1220  * hvc_iucv_setup_filter() - Set up z/VM user ID filter
1221  * @filter:     String consisting of a comma-separated list of z/VM user IDs
1222  *
1223  * The function parses the @filter string and creates an array containing
1224  * the list of z/VM user ID filter entries.
1225  * Return code 0 means success, -EINVAL if the filter is syntactically
1226  * incorrect, -ENOMEM if there was not enough memory to allocate the
1227  * filter list array, or -ENOSPC if too many z/VM user IDs have been specified.
1228  */
1229 static int hvc_iucv_setup_filter(const char *val)
1230 {
1231         const char *residual;
1232         int err;
1233         size_t size, count;
1234         void *array, *old_filter;
1235
1236         count = strlen(val);
1237         if (count == 0 || (count == 1 && val[0] == '\n')) {
1238                 size  = 0;
1239                 array = NULL;
1240                 goto out_replace_filter;        /* clear filter */
1241         }
1242
1243         /* count user IDs in order to allocate sufficient memory */
1244         size = 1;
1245         residual = val;
1246         while ((residual = strchr(residual, ',')) != NULL) {
1247                 residual++;
1248                 size++;
1249         }
1250
1251         /* check if the specified list exceeds the filter limit */
1252         if (size > MAX_VMID_FILTER)
1253                 return -ENOSPC;
1254
1255         array = kcalloc(size, 8, GFP_KERNEL);
1256         if (!array)
1257                 return -ENOMEM;
1258
1259         count = size;
1260         residual = val;
1261         while (*residual && count) {
1262                 residual = hvc_iucv_parse_filter(residual,
1263                                                  array + ((size - count) * 8));
1264                 if (IS_ERR(residual)) {
1265                         err = PTR_ERR(residual);
1266                         kfree(array);
1267                         goto out_err;
1268                 }
1269                 count--;
1270         }
1271
1272 out_replace_filter:
1273         write_lock_bh(&hvc_iucv_filter_lock);
1274         old_filter = hvc_iucv_filter;
1275         hvc_iucv_filter_size = size;
1276         hvc_iucv_filter = array;
1277         write_unlock_bh(&hvc_iucv_filter_lock);
1278         kfree(old_filter);
1279
1280         err = 0;
1281 out_err:
1282         return err;
1283 }
1284
1285 /**
1286  * param_set_vmidfilter() - Set z/VM user ID filter parameter
1287  * @val:        String consisting of a comma-separated list of z/VM user IDs
1288  * @kp:         Kernel parameter pointing to hvc_iucv_filter array
1289  *
1290  * The function sets up the z/VM user ID filter specified as comma-separated
1291  * list of user IDs in @val.
1292  * Note: If it is called early in the boot process, @val is stored and
1293  *       parsed later in hvc_iucv_init().
1294  */
1295 static int param_set_vmidfilter(const char *val, const struct kernel_param *kp)
1296 {
1297         int rc;
1298
1299         if (!MACHINE_IS_VM || !hvc_iucv_devices)
1300                 return -ENODEV;
1301
1302         if (!val)
1303                 return -EINVAL;
1304
1305         rc = 0;
1306         if (slab_is_available())
1307                 rc = hvc_iucv_setup_filter(val);
1308         else
1309                 hvc_iucv_filter_string = val;   /* defer... */
1310         return rc;
1311 }
1312
1313 /**
1314  * param_get_vmidfilter() - Get z/VM user ID filter
1315  * @buffer:     Buffer to store z/VM user ID filter,
1316  *              (buffer size assumption PAGE_SIZE)
1317  * @kp:         Kernel parameter pointing to the hvc_iucv_filter array
1318  *
1319  * The function stores the filter as a comma-separated list of z/VM user IDs
1320  * in @buffer. Typically, sysfs routines call this function for attr show.
1321  */
1322 static int param_get_vmidfilter(char *buffer, const struct kernel_param *kp)
1323 {
1324         int rc;
1325         size_t index, len;
1326         void *start, *end;
1327
1328         if (!MACHINE_IS_VM || !hvc_iucv_devices)
1329                 return -ENODEV;
1330
1331         rc = 0;
1332         read_lock_bh(&hvc_iucv_filter_lock);
1333         for (index = 0; index < hvc_iucv_filter_size; index++) {
1334                 start = hvc_iucv_filter + (8 * index);
1335                 end   = memchr(start, ' ', 8);
1336                 len   = (end) ? end - start : 8;
1337                 memcpy(buffer + rc, start, len);
1338                 rc += len;
1339                 buffer[rc++] = ',';
1340         }
1341         read_unlock_bh(&hvc_iucv_filter_lock);
1342         if (rc)
1343                 buffer[--rc] = '\0';    /* replace last comma and update rc */
1344         return rc;
1345 }
1346
1347 #define param_check_vmidfilter(name, p) __param_check(name, p, void)
1348
1349 static const struct kernel_param_ops param_ops_vmidfilter = {
1350         .set = param_set_vmidfilter,
1351         .get = param_get_vmidfilter,
1352 };
1353
1354 /**
1355  * hvc_iucv_init() - z/VM IUCV HVC device driver initialization
1356  */
1357 static int __init hvc_iucv_init(void)
1358 {
1359         int rc;
1360         unsigned int i;
1361
1362         if (!hvc_iucv_devices)
1363                 return -ENODEV;
1364
1365         if (!MACHINE_IS_VM) {
1366                 pr_notice("The z/VM IUCV HVC device driver cannot "
1367                            "be used without z/VM\n");
1368                 rc = -ENODEV;
1369                 goto out_error;
1370         }
1371
1372         if (hvc_iucv_devices > MAX_HVC_IUCV_LINES) {
1373                 pr_err("%lu is not a valid value for the hvc_iucv= "
1374                         "kernel parameter\n", hvc_iucv_devices);
1375                 rc = -EINVAL;
1376                 goto out_error;
1377         }
1378
1379         /* register IUCV HVC device driver */
1380         rc = driver_register(&hvc_iucv_driver);
1381         if (rc)
1382                 goto out_error;
1383
1384         /* parse hvc_iucv_allow string and create z/VM user ID filter list */
1385         if (hvc_iucv_filter_string) {
1386                 rc = hvc_iucv_setup_filter(hvc_iucv_filter_string);
1387                 switch (rc) {
1388                 case 0:
1389                         break;
1390                 case -ENOMEM:
1391                         pr_err("Allocating memory failed with "
1392                                 "reason code=%d\n", 3);
1393                         goto out_error;
1394                 case -EINVAL:
1395                         pr_err("hvc_iucv_allow= does not specify a valid "
1396                                 "z/VM user ID list\n");
1397                         goto out_error;
1398                 case -ENOSPC:
1399                         pr_err("hvc_iucv_allow= specifies too many "
1400                                 "z/VM user IDs\n");
1401                         goto out_error;
1402                 default:
1403                         goto out_error;
1404                 }
1405         }
1406
1407         hvc_iucv_buffer_cache = kmem_cache_create(KMSG_COMPONENT,
1408                                            sizeof(struct iucv_tty_buffer),
1409                                            0, 0, NULL);
1410         if (!hvc_iucv_buffer_cache) {
1411                 pr_err("Allocating memory failed with reason code=%d\n", 1);
1412                 rc = -ENOMEM;
1413                 goto out_error;
1414         }
1415
1416         hvc_iucv_mempool = mempool_create_slab_pool(MEMPOOL_MIN_NR,
1417                                                     hvc_iucv_buffer_cache);
1418         if (!hvc_iucv_mempool) {
1419                 pr_err("Allocating memory failed with reason code=%d\n", 2);
1420                 kmem_cache_destroy(hvc_iucv_buffer_cache);
1421                 rc = -ENOMEM;
1422                 goto out_error;
1423         }
1424
1425         /* register the first terminal device as console
1426          * (must be done before allocating hvc terminal devices) */
1427         rc = hvc_instantiate(HVC_IUCV_MAGIC, IUCV_HVC_CON_IDX, &hvc_iucv_ops);
1428         if (rc) {
1429                 pr_err("Registering HVC terminal device as "
1430                        "Linux console failed\n");
1431                 goto out_error_memory;
1432         }
1433
1434         /* allocate hvc_iucv_private structs */
1435         for (i = 0; i < hvc_iucv_devices; i++) {
1436                 rc = hvc_iucv_alloc(i, (i == IUCV_HVC_CON_IDX) ? 1 : 0);
1437                 if (rc) {
1438                         pr_err("Creating a new HVC terminal device "
1439                                 "failed with error code=%d\n", rc);
1440                         goto out_error_hvc;
1441                 }
1442         }
1443
1444         /* register IUCV callback handler */
1445         rc = iucv_register(&hvc_iucv_handler, 0);
1446         if (rc) {
1447                 pr_err("Registering IUCV handlers failed with error code=%d\n",
1448                         rc);
1449                 goto out_error_hvc;
1450         }
1451
1452         return 0;
1453
1454 out_error_hvc:
1455         for (i = 0; i < hvc_iucv_devices; i++)
1456                 if (hvc_iucv_table[i])
1457                         hvc_iucv_destroy(hvc_iucv_table[i]);
1458 out_error_memory:
1459         mempool_destroy(hvc_iucv_mempool);
1460         kmem_cache_destroy(hvc_iucv_buffer_cache);
1461 out_error:
1462         kfree(hvc_iucv_filter);
1463         hvc_iucv_devices = 0; /* ensure that we do not provide any device */
1464         return rc;
1465 }
1466
1467 /**
1468  * hvc_iucv_config() - Parsing of hvc_iucv=  kernel command line parameter
1469  * @val:        Parameter value (numeric)
1470  */
1471 static  int __init hvc_iucv_config(char *val)
1472 {
1473         if (kstrtoul(val, 10, &hvc_iucv_devices))
1474                 pr_warn("hvc_iucv= invalid parameter value '%s'\n", val);
1475         return 1;
1476 }
1477
1478
1479 device_initcall(hvc_iucv_init);
1480 __setup("hvc_iucv=", hvc_iucv_config);
1481 core_param(hvc_iucv_allow, hvc_iucv_filter, vmidfilter, 0640);