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 MAX_HVC_IUCV_LINES      HVC_ALLOC_TTY_ADAPTERS
  33 #define MEMPOOL_MIN_NR          (PAGE_SIZE / sizeof(struct iucv_tty_buffer)/4)
  34
  35 /* IUCV TTY message  */
  36 #define MSG_VERSION             0x02    /* Message version */
  37 #define MSG_TYPE_ERROR          0x01    /* Error message */
  38 #define MSG_TYPE_TERMENV        0x02    /* Terminal environment variable */
  39 #define MSG_TYPE_TERMIOS        0x04    /* Terminal IO struct update */
  40 #define MSG_TYPE_WINSIZE        0x08    /* Terminal window size update */
  41 #define MSG_TYPE_DATA           0x10    /* Terminal data */
  42
  43 struct iucv_tty_msg {
  44         u8      version;                /* Message version */
  45         u8      type;                   /* Message type */
  46 #define MSG_MAX_DATALEN         ((u16)(~0))
  47         u16     datalen;                /* Payload length */
  48         u8      data[];                 /* Payload buffer */
  49 } __attribute__((packed));
  50 #define MSG_SIZE(s)             ((s) + offsetof(struct iucv_tty_msg, data))
  51
  52 enum iucv_state_t {
  53         IUCV_DISCONN    = 0,
  54         IUCV_CONNECTED  = 1,
  55         IUCV_SEVERED    = 2,
  56 };
  57
  58 enum tty_state_t {
  59         TTY_CLOSED      = 0,
  60         TTY_OPENED      = 1,
  61 };
  62
  63 struct hvc_iucv_private {
  64         struct hvc_struct       *hvc;           /* HVC struct reference */
  65         u8                      srv_name[8];    /* IUCV service name (ebcdic) */
  66         unsigned char           is_console;     /* Linux console usage flag */
  67         enum iucv_state_t       iucv_state;     /* IUCV connection status */
  68         enum tty_state_t        tty_state;      /* TTY status */
  69         struct iucv_path        *path;          /* IUCV path pointer */
  70         spinlock_t              lock;           /* hvc_iucv_private lock */
  71 #define SNDBUF_SIZE             (PAGE_SIZE)     /* must be < MSG_MAX_DATALEN */
  72         void                    *sndbuf;        /* send buffer            */
  73         size_t                  sndbuf_len;     /* length of send buffer  */
  74 #define QUEUE_SNDBUF_DELAY      (HZ / 25)
  75         struct delayed_work     sndbuf_work;    /* work: send iucv msg(s) */
  76         wait_queue_head_t       sndbuf_waitq;   /* wait for send completion */
  77         struct list_head        tty_outqueue;   /* outgoing IUCV messages */
  78         struct list_head        tty_inqueue;    /* incoming IUCV messages */
  79         struct device           *dev;           /* device structure */
  80         u8                      info_path[16];  /* IUCV path info (dev attr) */
  81 };
  82
  83 struct iucv_tty_buffer {
  84         struct list_head        list;   /* list pointer */
  85         struct iucv_message     msg;    /* store an IUCV message */
  86         size_t                  offset; /* data buffer offset */
  87         struct iucv_tty_msg     *mbuf;  /* buffer to store input/output data */
  88 };
  89
  90 /* IUCV callback handler */
  91 static  int hvc_iucv_path_pending(struct iucv_path *, u8 *, u8 *);
  92 static void hvc_iucv_path_severed(struct iucv_path *, u8 *);
  93 static void hvc_iucv_msg_pending(struct iucv_path *, struct iucv_message *);
  94 static void hvc_iucv_msg_complete(struct iucv_path *, struct iucv_message *);
  95
  96
  97 /* Kernel module parameter: use one terminal device as default */
  98 static unsigned long hvc_iucv_devices = 1;
  99
 100 /* Array of allocated hvc iucv tty lines... */
 101 static struct hvc_iucv_private *hvc_iucv_table[MAX_HVC_IUCV_LINES];
 102 #define IUCV_HVC_CON_IDX        (0)
 103 /* List of z/VM user ID filter entries (struct iucv_vmid_filter) */
 104 #define MAX_VMID_FILTER         (500)
 105 #define FILTER_WILDCARD_CHAR    '*'
 106 static size_t hvc_iucv_filter_size;
 107 static void *hvc_iucv_filter;
 108 static const char *hvc_iucv_filter_string;
 109 static DEFINE_RWLOCK(hvc_iucv_filter_lock);
 110
 111 /* Kmem cache and mempool for iucv_tty_buffer elements */
 112 static struct kmem_cache *hvc_iucv_buffer_cache;
 113 static mempool_t *hvc_iucv_mempool;
 114
 115 /* IUCV handler callback functions */
 116 static struct iucv_handler hvc_iucv_handler = {
 117         .path_pending  = hvc_iucv_path_pending,
 118         .path_severed  = hvc_iucv_path_severed,
 119         .message_complete = hvc_iucv_msg_complete,
 120         .message_pending  = hvc_iucv_msg_pending,
 121 };
 122
 123
 124 /**
 125  * hvc_iucv_get_private() - Return a struct hvc_iucv_private instance.
 126  * @num:        The HVC virtual terminal number (vtermno)
 127  *
 128  * This function returns the struct hvc_iucv_private instance that corresponds
 129  * to the HVC virtual terminal number specified as parameter @num.
 130  */
 131 static struct hvc_iucv_private *hvc_iucv_get_private(uint32_t num)
 132 {
 133         if (num > hvc_iucv_devices)
 134                 return NULL;
 135         return hvc_iucv_table[num];
 136 }
 137
 138 /**
 139  * alloc_tty_buffer() - Return a new struct iucv_tty_buffer element.
 140  * @size:       Size of the internal buffer used to store data.
 141  * @flags:      Memory allocation flags passed to mempool.
 142  *
 143  * This function allocates a new struct iucv_tty_buffer element and, optionally,
 144  * allocates an internal data buffer with the specified size @size.
 145  * The internal data buffer is always allocated with GFP_DMA which is
 146  * required for receiving and sending data with IUCV.
 147  * Note: The total message size arises from the internal buffer size and the
 148  *       members of the iucv_tty_msg structure.
 149  * The function returns NULL if memory allocation has failed.
 150  */
 151 static struct iucv_tty_buffer *alloc_tty_buffer(size_t size, gfp_t flags)
 152 {
 153         struct iucv_tty_buffer *bufp;
 154
 155         bufp = mempool_alloc(hvc_iucv_mempool, flags);
 156         if (!bufp)
 157                 return NULL;
 158         memset(bufp, 0, sizeof(*bufp));
 159
 160         if (size > 0) {
 161                 bufp->msg.length = MSG_SIZE(size);
 162                 bufp->mbuf = kmalloc(bufp->msg.length, flags | GFP_DMA);
 163                 if (!bufp->mbuf) {
 164                         mempool_free(bufp, hvc_iucv_mempool);
 165                         return NULL;
 166                 }
 167                 bufp->mbuf->version = MSG_VERSION;
 168                 bufp->mbuf->type    = MSG_TYPE_DATA;
 169                 bufp->mbuf->datalen = (u16) size;
 170         }
 171         return bufp;
 172 }
 173
 174 /**
 175  * destroy_tty_buffer() - destroy struct iucv_tty_buffer element.
 176  * @bufp:       Pointer to a struct iucv_tty_buffer element, SHALL NOT be NULL.
 177  */
 178 static void destroy_tty_buffer(struct iucv_tty_buffer *bufp)
 179 {
 180         kfree(bufp->mbuf);
 181         mempool_free(bufp, hvc_iucv_mempool);
 182 }
 183
 184 /**
 185  * destroy_tty_buffer_list() - call destroy_tty_buffer() for each list element.
 186  * @list:       List containing struct iucv_tty_buffer elements.
 187  */
 188 static void destroy_tty_buffer_list(struct list_head *list)
 189 {
 190         struct iucv_tty_buffer *ent, *next;
 191
 192         list_for_each_entry_safe(ent, next, list, list) {
 193                 list_del(&ent->list);
 194                 destroy_tty_buffer(ent);
 195         }
 196 }
 197
 198 /**
 199  * hvc_iucv_write() - Receive IUCV message & write data to HVC buffer.
 200  * @priv:               Pointer to struct hvc_iucv_private
 201  * @buf:                HVC buffer for writing received terminal data.
 202  * @count:              HVC buffer size.
 203  * @has_more_data:      Pointer to an int variable.
 204  *
 205  * The function picks up pending messages from the input queue and receives
 206  * the message data that is then written to the specified buffer @buf.
 207  * If the buffer size @count is less than the data message size, the
 208  * message is kept on the input queue and @has_more_data is set to 1.
 209  * If all message data has been written, the message is removed from
 210  * the input queue.
 211  *
 212  * The function returns the number of bytes written to the terminal, zero if
 213  * there are no pending data messages available or if there is no established
 214  * IUCV path.
 215  * If the IUCV path has been severed, then -EPIPE is returned to cause a
 216  * hang up (that is issued by the HVC layer).
 217  */
 218 static ssize_t hvc_iucv_write(struct hvc_iucv_private *priv,
 219                               u8 *buf, size_t count, int *has_more_data)
 220 {
 221         struct iucv_tty_buffer *rb;
 222         ssize_t written;
 223         int rc;
 224
 225         /* immediately return if there is no IUCV connection */
 226         if (priv->iucv_state == IUCV_DISCONN)
 227                 return 0;
 228
 229         /* if the IUCV path has been severed, return -EPIPE to inform the
 230          * HVC layer to hang up the tty device. */
 231         if (priv->iucv_state == IUCV_SEVERED)
 232                 return -EPIPE;
 233
 234         /* check if there are pending messages */
 235         if (list_empty(&priv->tty_inqueue))
 236                 return 0;
 237
 238         /* receive an iucv message and flip data to the tty (ldisc) */
 239         rb = list_first_entry(&priv->tty_inqueue, struct iucv_tty_buffer, list);
 240
 241         written = 0;
 242         if (!rb->mbuf) { /* message not yet received ... */
 243                 /* allocate mem to store msg data; if no memory is available
 244                  * then leave the buffer on the list and re-try later */
 245                 rb->mbuf = kmalloc(rb->msg.length, GFP_ATOMIC | GFP_DMA);
 246                 if (!rb->mbuf)
 247                         return -ENOMEM;
 248
 249                 rc = __iucv_message_receive(priv->path, &rb->msg, 0,
 250                                             rb->mbuf, rb->msg.length, NULL);
 251                 switch (rc) {
 252                 case 0: /* Successful       */
 253                         break;
 254                 case 2: /* No message found */
 255                 case 9: /* Message purged   */
 256                         break;
 257                 default:
 258                         written = -EIO;
 259                 }
 260                 /* remove buffer if an error has occurred or received data
 261                  * is not correct */
 262                 if (rc || (rb->mbuf->version != MSG_VERSION) ||
 263                           (rb->msg.length    != MSG_SIZE(rb->mbuf->datalen)))
 264                         goto out_remove_buffer;
 265         }
 266
 267         switch (rb->mbuf->type) {
 268         case MSG_TYPE_DATA:
 269                 written = min_t(int, rb->mbuf->datalen - rb->offset, count);
 270                 memcpy(buf, rb->mbuf->data + rb->offset, written);
 271                 if (written < (rb->mbuf->datalen - rb->offset)) {
 272                         rb->offset += written;
 273                         *has_more_data = 1;
 274                         goto out_written;
 275                 }
 276                 break;
 277
 278         case MSG_TYPE_WINSIZE:
 279                 if (rb->mbuf->datalen != sizeof(struct winsize))
 280                         break;
 281                 /* The caller must ensure that the hvc is locked, which
 282                  * is the case when called from hvc_iucv_get_chars() */
 283                 __hvc_resize(priv->hvc, *((struct winsize *) rb->mbuf->data));
 284                 break;
 285
 286         case MSG_TYPE_ERROR:    /* ignored ... */
 287         case MSG_TYPE_TERMENV:  /* ignored ... */
 288         case MSG_TYPE_TERMIOS:  /* ignored ... */
 289                 break;
 290         }
 291
 292 out_remove_buffer:
 293         list_del(&rb->list);
 294         destroy_tty_buffer(rb);
 295         *has_more_data = !list_empty(&priv->tty_inqueue);
 296
 297 out_written:
 298         return written;
 299 }
 300
 301 /**
 302  * hvc_iucv_get_chars() - HVC get_chars operation.
 303  * @vtermno:    HVC virtual terminal number.
 304  * @buf:        Pointer to a buffer to store data
 305  * @count:      Size of buffer available for writing
 306  *
 307  * The HVC thread calls this method to read characters from the back-end.
 308  * If an IUCV communication path has been established, pending IUCV messages
 309  * are received and data is copied into buffer @buf up to @count bytes.
 310  *
 311  * Locking:     The routine gets called under an irqsave() spinlock; and
 312  *              the routine locks the struct hvc_iucv_private->lock to call
 313  *              helper functions.
 314  */
 315 static ssize_t hvc_iucv_get_chars(uint32_t vtermno, u8 *buf, size_t count)
 316 {
 317         struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 318         ssize_t written;
 319         int has_more_data;
 320
 321         if (count <= 0)
 322                 return 0;
 323
 324         if (!priv)
 325                 return -ENODEV;
 326
 327         spin_lock(&priv->lock);
 328         has_more_data = 0;
 329         written = hvc_iucv_write(priv, buf, count, &has_more_data);
 330         spin_unlock(&priv->lock);
 331
 332         /* if there are still messages on the queue... schedule another run */
 333         if (has_more_data)
 334                 hvc_kick();
 335
 336         return written;
 337 }
 338
 339 /**
 340  * hvc_iucv_queue() - Buffer terminal data for sending.
 341  * @priv:       Pointer to struct hvc_iucv_private instance.
 342  * @buf:        Buffer containing data to send.
 343  * @count:      Size of buffer and amount of data to send.
 344  *
 345  * The function queues data for sending. To actually send the buffered data,
 346  * a work queue function is scheduled (with QUEUE_SNDBUF_DELAY).
 347  * The function returns the number of data bytes that has been buffered.
 348  *
 349  * If the device is not connected, data is ignored and the function returns
 350  * @count.
 351  * If the buffer is full, the function returns 0.
 352  * If an existing IUCV communicaton path has been severed, -EPIPE is returned
 353  * (that can be passed to HVC layer to cause a tty hangup).
 354  */
 355 static ssize_t hvc_iucv_queue(struct hvc_iucv_private *priv, const u8 *buf,
 356                               size_t count)
 357 {
 358         size_t len;
 359
 360         if (priv->iucv_state == IUCV_DISCONN)
 361                 return count;                   /* ignore data */
 362
 363         if (priv->iucv_state == IUCV_SEVERED)
 364                 return -EPIPE;
 365
 366         len = min_t(size_t, count, SNDBUF_SIZE - priv->sndbuf_len);
 367         if (!len)
 368                 return 0;
 369
 370         memcpy(priv->sndbuf + priv->sndbuf_len, buf, len);
 371         priv->sndbuf_len += len;
 372
 373         if (priv->iucv_state == IUCV_CONNECTED)
 374                 schedule_delayed_work(&priv->sndbuf_work, QUEUE_SNDBUF_DELAY);
 375
 376         return len;
 377 }
 378
 379 /**
 380  * hvc_iucv_send() - Send an IUCV message containing terminal data.
 381  * @priv:       Pointer to struct hvc_iucv_private instance.
 382  *
 383  * If an IUCV communication path has been established, the buffered output data
 384  * is sent via an IUCV message and the number of bytes sent is returned.
 385  * Returns 0 if there is no established IUCV communication path or
 386  * -EPIPE if an existing IUCV communicaton path has been severed.
 387  */
 388 static int hvc_iucv_send(struct hvc_iucv_private *priv)
 389 {
 390         struct iucv_tty_buffer *sb;
 391         int rc, len;
 392
 393         if (priv->iucv_state == IUCV_SEVERED)
 394                 return -EPIPE;
 395
 396         if (priv->iucv_state == IUCV_DISCONN)
 397                 return -EIO;
 398
 399         if (!priv->sndbuf_len)
 400                 return 0;
 401
 402         /* allocate internal buffer to store msg data and also compute total
 403          * message length */
 404         sb = alloc_tty_buffer(priv->sndbuf_len, GFP_ATOMIC);
 405         if (!sb)
 406                 return -ENOMEM;
 407
 408         memcpy(sb->mbuf->data, priv->sndbuf, priv->sndbuf_len);
 409         sb->mbuf->datalen = (u16) priv->sndbuf_len;
 410         sb->msg.length = MSG_SIZE(sb->mbuf->datalen);
 411
 412         list_add_tail(&sb->list, &priv->tty_outqueue);
 413
 414         rc = __iucv_message_send(priv->path, &sb->msg, 0, 0,
 415                                  (void *) sb->mbuf, sb->msg.length);
 416         if (rc) {
 417                 /* drop the message here; however we might want to handle
 418                  * 0x03 (msg limit reached) by trying again... */
 419                 list_del(&sb->list);
 420                 destroy_tty_buffer(sb);
 421         }
 422         len = priv->sndbuf_len;
 423         priv->sndbuf_len = 0;
 424
 425         return len;
 426 }
 427
 428 /**
 429  * hvc_iucv_sndbuf_work() - Send buffered data over IUCV
 430  * @work:       Work structure.
 431  *
 432  * This work queue function sends buffered output data over IUCV and,
 433  * if not all buffered data could be sent, reschedules itself.
 434  */
 435 static void hvc_iucv_sndbuf_work(struct work_struct *work)
 436 {
 437         struct hvc_iucv_private *priv;
 438
 439         priv = container_of(work, struct hvc_iucv_private, sndbuf_work.work);
 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 ssize_t hvc_iucv_put_chars(uint32_t vtermno, const u8 *buf, size_t count)
 459 {
 460         struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 461         int queued;
 462
 463         if (!count)
 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  * @active:     True to raise or false 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, bool active)
 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 (active)
 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 that is specified with @ipvmid is permitted to
 737  * connect, otherwise non-zero.
 738  */
 739 static int hvc_iucv_filter_connreq(u8 ipvmid[8])
 740 {
 741         const char *wildcard, *filter_entry;
 742         size_t i, len;
 743
 744         /* Note: default policy is ACCEPT if no filter is set */
 745         if (!hvc_iucv_filter_size)
 746                 return 0;
 747
 748         for (i = 0; i < hvc_iucv_filter_size; i++) {
 749                 filter_entry = hvc_iucv_filter + (8 * i);
 750
 751                 /* If a filter entry contains the filter wildcard character,
 752                  * reduce the length to match the leading portion of the user
 753                  * ID only (wildcard match).  Characters following the wildcard
 754                  * are ignored.
 755                  */
 756                 wildcard = strnchr(filter_entry, 8, FILTER_WILDCARD_CHAR);
 757                 len = (wildcard) ? wildcard - filter_entry : 8;
 758                 if (0 == memcmp(ipvmid, filter_entry, len))
 759                         return 0;
 760         }
 761         return 1;
 762 }
 763
 764 /**
 765  * hvc_iucv_path_pending() - IUCV handler to process a connection request.
 766  * @path:       Pending path (struct iucv_path)
 767  * @ipvmid:     z/VM system identifier of originator
 768  * @ipuser:     User specified data for this path
 769  *              (AF_IUCV: port/service name and originator port)
 770  *
 771  * The function uses the @ipuser data to determine if the pending path belongs
 772  * to a terminal managed by this device driver.
 773  * If the path belongs to this driver, ensure that the terminal is not accessed
 774  * multiple times (only one connection to a terminal is allowed).
 775  * If the terminal is not yet connected, the pending path is accepted and is
 776  * associated to the appropriate struct hvc_iucv_private instance.
 777  *
 778  * Returns 0 if @path belongs to a terminal managed by the this device driver;
 779  * otherwise returns -ENODEV in order to dispatch this path to other handlers.
 780  *
 781  * Locking:     struct hvc_iucv_private->lock
 782  */
 783 static  int hvc_iucv_path_pending(struct iucv_path *path, u8 *ipvmid,
 784                                   u8 *ipuser)
 785 {
 786         struct hvc_iucv_private *priv, *tmp;
 787         u8 wildcard[9] = "lnxhvc  ";
 788         int i, rc, find_unused;
 789         u8 nuser_data[16];
 790         u8 vm_user_id[9];
 791
 792         ASCEBC(wildcard, sizeof(wildcard));
 793         find_unused = !memcmp(wildcard, ipuser, 8);
 794
 795         /* First, check if the pending path request is managed by this
 796          * IUCV handler:
 797          * - find a disconnected device if ipuser contains the wildcard
 798          * - find the device that matches the terminal ID in ipuser
 799          */
 800         priv = NULL;
 801         for (i = 0; i < hvc_iucv_devices; i++) {
 802                 tmp = hvc_iucv_table[i];
 803                 if (!tmp)
 804                         continue;
 805
 806                 if (find_unused) {
 807                         spin_lock(&tmp->lock);
 808                         if (tmp->iucv_state == IUCV_DISCONN)
 809                                 priv = tmp;
 810                         spin_unlock(&tmp->lock);
 811
 812                 } else if (!memcmp(tmp->srv_name, ipuser, 8))
 813                                 priv = tmp;
 814                 if (priv)
 815                         break;
 816         }
 817         if (!priv)
 818                 return -ENODEV;
 819
 820         /* Enforce that ipvmid is allowed to connect to us */
 821         read_lock(&hvc_iucv_filter_lock);
 822         rc = hvc_iucv_filter_connreq(ipvmid);
 823         read_unlock(&hvc_iucv_filter_lock);
 824         if (rc) {
 825                 iucv_path_sever(path, ipuser);
 826                 iucv_path_free(path);
 827                 memcpy(vm_user_id, ipvmid, 8);
 828                 vm_user_id[8] = 0;
 829                 pr_info("A connection request from z/VM user ID %s "
 830                         "was refused\n", vm_user_id);
 831                 return 0;
 832         }
 833
 834         spin_lock(&priv->lock);
 835
 836         /* If the terminal is already connected or being severed, then sever
 837          * this path to enforce that there is only ONE established communication
 838          * path per terminal. */
 839         if (priv->iucv_state != IUCV_DISCONN) {
 840                 iucv_path_sever(path, ipuser);
 841                 iucv_path_free(path);
 842                 goto out_path_handled;
 843         }
 844
 845         /* accept path */
 846         memcpy(nuser_data, ipuser + 8, 8);  /* remote service (for af_iucv) */
 847         memcpy(nuser_data + 8, ipuser, 8);  /* local service  (for af_iucv) */
 848         path->msglim = 0xffff;              /* IUCV MSGLIMIT */
 849         path->flags &= ~IUCV_IPRMDATA;      /* TODO: use IUCV_IPRMDATA */
 850         rc = iucv_path_accept(path, &hvc_iucv_handler, nuser_data, priv);
 851         if (rc) {
 852                 iucv_path_sever(path, ipuser);
 853                 iucv_path_free(path);
 854                 goto out_path_handled;
 855         }
 856         priv->path = path;
 857         priv->iucv_state = IUCV_CONNECTED;
 858
 859         /* store path information */
 860         memcpy(priv->info_path, ipvmid, 8);
 861         memcpy(priv->info_path + 8, ipuser + 8, 8);
 862
 863         /* flush buffered output data... */
 864         schedule_delayed_work(&priv->sndbuf_work, 5);
 865
 866 out_path_handled:
 867         spin_unlock(&priv->lock);
 868         return 0;
 869 }
 870
 871 /**
 872  * hvc_iucv_path_severed() - IUCV handler to process a path sever.
 873  * @path:       Pending path (struct iucv_path)
 874  * @ipuser:     User specified data for this path
 875  *              (AF_IUCV: port/service name and originator port)
 876  *
 877  * This function calls the hvc_iucv_hangup() function for the
 878  * respective IUCV HVC terminal.
 879  *
 880  * Locking:     struct hvc_iucv_private->lock
 881  */
 882 static void hvc_iucv_path_severed(struct iucv_path *path, u8 *ipuser)
 883 {
 884         struct hvc_iucv_private *priv = path->private;
 885
 886         hvc_iucv_hangup(priv);
 887 }
 888
 889 /**
 890  * hvc_iucv_msg_pending() - IUCV handler to process an incoming IUCV message.
 891  * @path:       Pending path (struct iucv_path)
 892  * @msg:        Pointer to the IUCV message
 893  *
 894  * The function puts an incoming message on the input queue for later
 895  * processing (by hvc_iucv_get_chars() / hvc_iucv_write()).
 896  * If the tty has not yet been opened, the message is rejected.
 897  *
 898  * Locking:     struct hvc_iucv_private->lock
 899  */
 900 static void hvc_iucv_msg_pending(struct iucv_path *path,
 901                                  struct iucv_message *msg)
 902 {
 903         struct hvc_iucv_private *priv = path->private;
 904         struct iucv_tty_buffer *rb;
 905
 906         /* reject messages that exceed max size of iucv_tty_msg->datalen */
 907         if (msg->length > MSG_SIZE(MSG_MAX_DATALEN)) {
 908                 iucv_message_reject(path, msg);
 909                 return;
 910         }
 911
 912         spin_lock(&priv->lock);
 913
 914         /* reject messages if tty has not yet been opened */
 915         if (priv->tty_state == TTY_CLOSED) {
 916                 iucv_message_reject(path, msg);
 917                 goto unlock_return;
 918         }
 919
 920         /* allocate tty buffer to save iucv msg only */
 921         rb = alloc_tty_buffer(0, GFP_ATOMIC);
 922         if (!rb) {
 923                 iucv_message_reject(path, msg);
 924                 goto unlock_return;     /* -ENOMEM */
 925         }
 926         rb->msg = *msg;
 927
 928         list_add_tail(&rb->list, &priv->tty_inqueue);
 929
 930         hvc_kick();     /* wake up hvc thread */
 931
 932 unlock_return:
 933         spin_unlock(&priv->lock);
 934 }
 935
 936 /**
 937  * hvc_iucv_msg_complete() - IUCV handler to process message completion
 938  * @path:       Pending path (struct iucv_path)
 939  * @msg:        Pointer to the IUCV message
 940  *
 941  * The function is called upon completion of message delivery to remove the
 942  * message from the outqueue. Additional delivery information can be found
 943  * msg->audit: rejected messages (0x040000 (IPADRJCT)), and
 944  *             purged messages   (0x010000 (IPADPGNR)).
 945  *
 946  * Locking:     struct hvc_iucv_private->lock
 947  */
 948 static void hvc_iucv_msg_complete(struct iucv_path *path,
 949                                   struct iucv_message *msg)
 950 {
 951         struct hvc_iucv_private *priv = path->private;
 952         struct iucv_tty_buffer  *ent, *next;
 953         LIST_HEAD(list_remove);
 954
 955         spin_lock(&priv->lock);
 956         list_for_each_entry_safe(ent, next, &priv->tty_outqueue, list)
 957                 if (ent->msg.id == msg->id) {
 958                         list_move(&ent->list, &list_remove);
 959                         break;
 960                 }
 961         wake_up(&priv->sndbuf_waitq);
 962         spin_unlock(&priv->lock);
 963         destroy_tty_buffer_list(&list_remove);
 964 }
 965
 966 static ssize_t hvc_iucv_dev_termid_show(struct device *dev,
 967                                         struct device_attribute *attr,
 968                                         char *buf)
 969 {
 970         struct hvc_iucv_private *priv = dev_get_drvdata(dev);
 971         size_t len;
 972
 973         len = sizeof(priv->srv_name);
 974         memcpy(buf, priv->srv_name, len);
 975         EBCASC(buf, len);
 976         buf[len++] = '\n';
 977         return len;
 978 }
 979
 980 static ssize_t hvc_iucv_dev_state_show(struct device *dev,
 981                                         struct device_attribute *attr,
 982                                         char *buf)
 983 {
 984         struct hvc_iucv_private *priv = dev_get_drvdata(dev);
 985         return sprintf(buf, "%u:%u\n", priv->iucv_state, priv->tty_state);
 986 }
 987
 988 static ssize_t hvc_iucv_dev_peer_show(struct device *dev,
 989                                       struct device_attribute *attr,
 990                                       char *buf)
 991 {
 992         struct hvc_iucv_private *priv = dev_get_drvdata(dev);
 993         char vmid[9], ipuser[9];
 994
 995         memset(vmid, 0, sizeof(vmid));
 996         memset(ipuser, 0, sizeof(ipuser));
 997
 998         spin_lock_bh(&priv->lock);
 999         if (priv->iucv_state == IUCV_CONNECTED) {
1000                 memcpy(vmid, priv->info_path, 8);
1001                 memcpy(ipuser, priv->info_path + 8, 8);
1002         }
1003         spin_unlock_bh(&priv->lock);
1004         EBCASC(ipuser, 8);
1005
1006         return sprintf(buf, "%s:%s\n", vmid, ipuser);
1007 }
1008
1009
1010 /* HVC operations */
1011 static const struct hv_ops hvc_iucv_ops = {
1012         .get_chars = hvc_iucv_get_chars,
1013         .put_chars = hvc_iucv_put_chars,
1014         .notifier_add = hvc_iucv_notifier_add,
1015         .notifier_del = hvc_iucv_notifier_del,
1016         .notifier_hangup = hvc_iucv_notifier_hangup,
1017         .dtr_rts = hvc_iucv_dtr_rts,
1018 };
1019
1020 /* IUCV HVC device attributes */
1021 static DEVICE_ATTR(termid, 0640, hvc_iucv_dev_termid_show, NULL);
1022 static DEVICE_ATTR(state, 0640, hvc_iucv_dev_state_show, NULL);
1023 static DEVICE_ATTR(peer, 0640, hvc_iucv_dev_peer_show, NULL);
1024 static struct attribute *hvc_iucv_dev_attrs[] = {
1025         &dev_attr_termid.attr,
1026         &dev_attr_state.attr,
1027         &dev_attr_peer.attr,
1028         NULL,
1029 };
1030 static struct attribute_group hvc_iucv_dev_attr_group = {
1031         .attrs = hvc_iucv_dev_attrs,
1032 };
1033 static const struct attribute_group *hvc_iucv_dev_attr_groups[] = {
1034         &hvc_iucv_dev_attr_group,
1035         NULL,
1036 };
1037
1038
1039 /**
1040  * hvc_iucv_alloc() - Allocates a new struct hvc_iucv_private instance
1041  * @id:                 hvc_iucv_table index
1042  * @is_console:         Flag if the instance is used as Linux console
1043  *
1044  * This function allocates a new hvc_iucv_private structure and stores
1045  * the instance in hvc_iucv_table at index @id.
1046  * Returns 0 on success; otherwise non-zero.
1047  */
1048 static int __init hvc_iucv_alloc(int id, unsigned int is_console)
1049 {
1050         struct hvc_iucv_private *priv;
1051         char name[9];
1052         int rc;
1053
1054         priv = kzalloc(sizeof(struct hvc_iucv_private), GFP_KERNEL);
1055         if (!priv)
1056                 return -ENOMEM;
1057
1058         spin_lock_init(&priv->lock);
1059         INIT_LIST_HEAD(&priv->tty_outqueue);
1060         INIT_LIST_HEAD(&priv->tty_inqueue);
1061         INIT_DELAYED_WORK(&priv->sndbuf_work, hvc_iucv_sndbuf_work);
1062         init_waitqueue_head(&priv->sndbuf_waitq);
1063
1064         priv->sndbuf = (void *) get_zeroed_page(GFP_KERNEL);
1065         if (!priv->sndbuf) {
1066                 kfree(priv);
1067                 return -ENOMEM;
1068         }
1069
1070         /* set console flag */
1071         priv->is_console = is_console;
1072
1073         /* allocate hvc device */
1074         priv->hvc = hvc_alloc(id, /*             PAGE_SIZE */
1075                               id, &hvc_iucv_ops, 256);
1076         if (IS_ERR(priv->hvc)) {
1077                 rc = PTR_ERR(priv->hvc);
1078                 goto out_error_hvc;
1079         }
1080
1081         /* notify HVC thread instead of using polling */
1082         priv->hvc->irq_requested = 1;
1083
1084         /* setup iucv related information */
1085         snprintf(name, 9, "lnxhvc%-2d", id);
1086         memcpy(priv->srv_name, name, 8);
1087         ASCEBC(priv->srv_name, 8);
1088
1089         /* create and setup device */
1090         priv->dev = kzalloc(sizeof(*priv->dev), GFP_KERNEL);
1091         if (!priv->dev) {
1092                 rc = -ENOMEM;
1093                 goto out_error_dev;
1094         }
1095         dev_set_name(priv->dev, "hvc_iucv%d", id);
1096         dev_set_drvdata(priv->dev, priv);
1097         priv->dev->bus = &iucv_bus;
1098         priv->dev->parent = iucv_root;
1099         priv->dev->groups = hvc_iucv_dev_attr_groups;
1100         priv->dev->release = (void (*)(struct device *)) kfree;
1101         rc = device_register(priv->dev);
1102         if (rc) {
1103                 put_device(priv->dev);
1104                 goto out_error_dev;
1105         }
1106
1107         hvc_iucv_table[id] = priv;
1108         return 0;
1109
1110 out_error_dev:
1111         hvc_remove(priv->hvc);
1112 out_error_hvc:
1113         free_page((unsigned long) priv->sndbuf);
1114         kfree(priv);
1115
1116         return rc;
1117 }
1118
1119 /**
1120  * hvc_iucv_destroy() - Destroy and free hvc_iucv_private instances
1121  */
1122 static void __init hvc_iucv_destroy(struct hvc_iucv_private *priv)
1123 {
1124         hvc_remove(priv->hvc);
1125         device_unregister(priv->dev);
1126         free_page((unsigned long) priv->sndbuf);
1127         kfree(priv);
1128 }
1129
1130 /**
1131  * hvc_iucv_parse_filter() - Parse filter for a single z/VM user ID
1132  * @filter:     String containing a comma-separated list of z/VM user IDs
1133  * @dest:       Location where to store the parsed z/VM user ID
1134  */
1135 static const char *hvc_iucv_parse_filter(const char *filter, char *dest)
1136 {
1137         const char *nextdelim, *residual;
1138         size_t len;
1139
1140         nextdelim = strchr(filter, ',');
1141         if (nextdelim) {
1142                 len = nextdelim - filter;
1143                 residual = nextdelim + 1;
1144         } else {
1145                 len = strlen(filter);
1146                 residual = filter + len;
1147         }
1148
1149         if (len == 0)
1150                 return ERR_PTR(-EINVAL);
1151
1152         /* check for '\n' (if called from sysfs) */
1153         if (filter[len - 1] == '\n')
1154                 len--;
1155
1156         /* prohibit filter entries containing the wildcard character only */
1157         if (len == 1 && *filter == FILTER_WILDCARD_CHAR)
1158                 return ERR_PTR(-EINVAL);
1159
1160         if (len > 8)
1161                 return ERR_PTR(-EINVAL);
1162
1163         /* pad with blanks and save upper case version of user ID */
1164         memset(dest, ' ', 8);
1165         while (len--)
1166                 dest[len] = toupper(filter[len]);
1167         return residual;
1168 }
1169
1170 /**
1171  * hvc_iucv_setup_filter() - Set up z/VM user ID filter
1172  * @filter:     String consisting of a comma-separated list of z/VM user IDs
1173  *
1174  * The function parses the @filter string and creates an array containing
1175  * the list of z/VM user ID filter entries.
1176  * Return code 0 means success, -EINVAL if the filter is syntactically
1177  * incorrect, -ENOMEM if there was not enough memory to allocate the
1178  * filter list array, or -ENOSPC if too many z/VM user IDs have been specified.
1179  */
1180 static int hvc_iucv_setup_filter(const char *val)
1181 {
1182         const char *residual;
1183         int err;
1184         size_t size, count;
1185         void *array, *old_filter;
1186
1187         count = strlen(val);
1188         if (count == 0 || (count == 1 && val[0] == '\n')) {
1189                 size  = 0;
1190                 array = NULL;
1191                 goto out_replace_filter;        /* clear filter */
1192         }
1193
1194         /* count user IDs in order to allocate sufficient memory */
1195         size = 1;
1196         residual = val;
1197         while ((residual = strchr(residual, ',')) != NULL) {
1198                 residual++;
1199                 size++;
1200         }
1201
1202         /* check if the specified list exceeds the filter limit */
1203         if (size > MAX_VMID_FILTER)
1204                 return -ENOSPC;
1205
1206         array = kcalloc(size, 8, GFP_KERNEL);
1207         if (!array)
1208                 return -ENOMEM;
1209
1210         count = size;
1211         residual = val;
1212         while (*residual && count) {
1213                 residual = hvc_iucv_parse_filter(residual,
1214                                                  array + ((size - count) * 8));
1215                 if (IS_ERR(residual)) {
1216                         err = PTR_ERR(residual);
1217                         kfree(array);
1218                         goto out_err;
1219                 }
1220                 count--;
1221         }
1222
1223 out_replace_filter:
1224         write_lock_bh(&hvc_iucv_filter_lock);
1225         old_filter = hvc_iucv_filter;
1226         hvc_iucv_filter_size = size;
1227         hvc_iucv_filter = array;
1228         write_unlock_bh(&hvc_iucv_filter_lock);
1229         kfree(old_filter);
1230
1231         err = 0;
1232 out_err:
1233         return err;
1234 }
1235
1236 /**
1237  * param_set_vmidfilter() - Set z/VM user ID filter parameter
1238  * @val:        String consisting of a comma-separated list of z/VM user IDs
1239  * @kp:         Kernel parameter pointing to hvc_iucv_filter array
1240  *
1241  * The function sets up the z/VM user ID filter specified as comma-separated
1242  * list of user IDs in @val.
1243  * Note: If it is called early in the boot process, @val is stored and
1244  *       parsed later in hvc_iucv_init().
1245  */
1246 static int param_set_vmidfilter(const char *val, const struct kernel_param *kp)
1247 {
1248         int rc;
1249
1250         if (!MACHINE_IS_VM || !hvc_iucv_devices)
1251                 return -ENODEV;
1252
1253         if (!val)
1254                 return -EINVAL;
1255
1256         rc = 0;
1257         if (slab_is_available())
1258                 rc = hvc_iucv_setup_filter(val);
1259         else
1260                 hvc_iucv_filter_string = val;   /* defer... */
1261         return rc;
1262 }
1263
1264 /**
1265  * param_get_vmidfilter() - Get z/VM user ID filter
1266  * @buffer:     Buffer to store z/VM user ID filter,
1267  *              (buffer size assumption PAGE_SIZE)
1268  * @kp:         Kernel parameter pointing to the hvc_iucv_filter array
1269  *
1270  * The function stores the filter as a comma-separated list of z/VM user IDs
1271  * in @buffer. Typically, sysfs routines call this function for attr show.
1272  */
1273 static int param_get_vmidfilter(char *buffer, const struct kernel_param *kp)
1274 {
1275         int rc;
1276         size_t index, len;
1277         void *start, *end;
1278
1279         if (!MACHINE_IS_VM || !hvc_iucv_devices)
1280                 return -ENODEV;
1281
1282         rc = 0;
1283         read_lock_bh(&hvc_iucv_filter_lock);
1284         for (index = 0; index < hvc_iucv_filter_size; index++) {
1285                 start = hvc_iucv_filter + (8 * index);
1286                 end   = memchr(start, ' ', 8);
1287                 len   = (end) ? end - start : 8;
1288                 memcpy(buffer + rc, start, len);
1289                 rc += len;
1290                 buffer[rc++] = ',';
1291         }
1292         read_unlock_bh(&hvc_iucv_filter_lock);
1293         if (rc)
1294                 buffer[--rc] = '\0';    /* replace last comma and update rc */
1295         return rc;
1296 }
1297
1298 #define param_check_vmidfilter(name, p) __param_check(name, p, void)
1299
1300 static const struct kernel_param_ops param_ops_vmidfilter = {
1301         .set = param_set_vmidfilter,
1302         .get = param_get_vmidfilter,
1303 };
1304
1305 /**
1306  * hvc_iucv_init() - z/VM IUCV HVC device driver initialization
1307  */
1308 static int __init hvc_iucv_init(void)
1309 {
1310         int rc;
1311         unsigned int i;
1312
1313         if (!hvc_iucv_devices)
1314                 return -ENODEV;
1315
1316         if (!MACHINE_IS_VM) {
1317                 pr_notice("The z/VM IUCV HVC device driver cannot "
1318                            "be used without z/VM\n");
1319                 rc = -ENODEV;
1320                 goto out_error;
1321         }
1322
1323         if (hvc_iucv_devices > MAX_HVC_IUCV_LINES) {
1324                 pr_err("%lu is not a valid value for the hvc_iucv= "
1325                         "kernel parameter\n", hvc_iucv_devices);
1326                 rc = -EINVAL;
1327                 goto out_error;
1328         }
1329
1330         /* parse hvc_iucv_allow string and create z/VM user ID filter list */
1331         if (hvc_iucv_filter_string) {
1332                 rc = hvc_iucv_setup_filter(hvc_iucv_filter_string);
1333                 switch (rc) {
1334                 case 0:
1335                         break;
1336                 case -ENOMEM:
1337                         pr_err("Allocating memory failed with "
1338                                 "reason code=%d\n", 3);
1339                         goto out_error;
1340                 case -EINVAL:
1341                         pr_err("hvc_iucv_allow= does not specify a valid "
1342                                 "z/VM user ID list\n");
1343                         goto out_error;
1344                 case -ENOSPC:
1345                         pr_err("hvc_iucv_allow= specifies too many "
1346                                 "z/VM user IDs\n");
1347                         goto out_error;
1348                 default:
1349                         goto out_error;
1350                 }
1351         }
1352
1353         hvc_iucv_buffer_cache = kmem_cache_create(KMSG_COMPONENT,
1354                                            sizeof(struct iucv_tty_buffer),
1355                                            0, 0, NULL);
1356         if (!hvc_iucv_buffer_cache) {
1357                 pr_err("Allocating memory failed with reason code=%d\n", 1);
1358                 rc = -ENOMEM;
1359                 goto out_error;
1360         }
1361
1362         hvc_iucv_mempool = mempool_create_slab_pool(MEMPOOL_MIN_NR,
1363                                                     hvc_iucv_buffer_cache);
1364         if (!hvc_iucv_mempool) {
1365                 pr_err("Allocating memory failed with reason code=%d\n", 2);
1366                 kmem_cache_destroy(hvc_iucv_buffer_cache);
1367                 rc = -ENOMEM;
1368                 goto out_error;
1369         }
1370
1371         /* register the first terminal device as console
1372          * (must be done before allocating hvc terminal devices) */
1373         rc = hvc_instantiate(0, IUCV_HVC_CON_IDX, &hvc_iucv_ops);
1374         if (rc) {
1375                 pr_err("Registering HVC terminal device as "
1376                        "Linux console failed\n");
1377                 goto out_error_memory;
1378         }
1379
1380         /* allocate hvc_iucv_private structs */
1381         for (i = 0; i < hvc_iucv_devices; i++) {
1382                 rc = hvc_iucv_alloc(i, (i == IUCV_HVC_CON_IDX) ? 1 : 0);
1383                 if (rc) {
1384                         pr_err("Creating a new HVC terminal device "
1385                                 "failed with error code=%d\n", rc);
1386                         goto out_error_hvc;
1387                 }
1388         }
1389
1390         /* register IUCV callback handler */
1391         rc = iucv_register(&hvc_iucv_handler, 0);
1392         if (rc) {
1393                 pr_err("Registering IUCV handlers failed with error code=%d\n",
1394                         rc);
1395                 goto out_error_hvc;
1396         }
1397
1398         return 0;
1399
1400 out_error_hvc:
1401         for (i = 0; i < hvc_iucv_devices; i++)
1402                 if (hvc_iucv_table[i])
1403                         hvc_iucv_destroy(hvc_iucv_table[i]);
1404 out_error_memory:
1405         mempool_destroy(hvc_iucv_mempool);
1406         kmem_cache_destroy(hvc_iucv_buffer_cache);
1407 out_error:
1408         kfree(hvc_iucv_filter);
1409         hvc_iucv_devices = 0; /* ensure that we do not provide any device */
1410         return rc;
1411 }
1412
1413 /**
1414  * hvc_iucv_config() - Parsing of hvc_iucv=  kernel command line parameter
1415  * @val:        Parameter value (numeric)
1416  */
1417 static  int __init hvc_iucv_config(char *val)
1418 {
1419         if (kstrtoul(val, 10, &hvc_iucv_devices))
1420                 pr_warn("hvc_iucv= invalid parameter value '%s'\n", val);
1421         return 1;
1422 }
1423
1424
1425 device_initcall(hvc_iucv_init);
1426 __setup("hvc_iucv=", hvc_iucv_config);
1427 core_param(hvc_iucv_allow, hvc_iucv_filter, vmidfilter, 0640);