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
 442         spin_lock_bh(&priv->lock);
 443         hvc_iucv_send(priv);
 444         spin_unlock_bh(&priv->lock);
 445 }
 446
 447 /**
 448  * hvc_iucv_put_chars() - HVC put_chars operation.
 449  * @vtermno:    HVC virtual terminal number.
 450  * @buf:        Pointer to an buffer to read data from
 451  * @count:      Size of buffer available for reading
 452  *
 453  * The HVC thread calls this method to write characters to the back-end.
 454  * The function calls hvc_iucv_queue() to queue terminal data for sending.
 455  *
 456  * Locking:     The method gets called under an irqsave() spinlock; and
 457  *              locks struct hvc_iucv_private->lock.
 458  */
 459 static int hvc_iucv_put_chars(uint32_t vtermno, const char *buf, int count)
 460 {
 461         struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 462         int queued;
 463
 464         if (count <= 0)
 465                 return 0;
 466
 467         if (!priv)
 468                 return -ENODEV;
 469
 470         spin_lock(&priv->lock);
 471         queued = hvc_iucv_queue(priv, buf, count);
 472         spin_unlock(&priv->lock);
 473
 474         return queued;
 475 }
 476
 477 /**
 478  * hvc_iucv_notifier_add() - HVC notifier for opening a TTY for the first time.
 479  * @hp: Pointer to the HVC device (struct hvc_struct)
 480  * @id: Additional data (originally passed to hvc_alloc): the index of an struct
 481  *      hvc_iucv_private instance.
 482  *
 483  * The function sets the tty state to TTY_OPENED for the struct hvc_iucv_private
 484  * instance that is derived from @id. Always returns 0.
 485  *
 486  * Locking:     struct hvc_iucv_private->lock, spin_lock_bh
 487  */
 488 static int hvc_iucv_notifier_add(struct hvc_struct *hp, int id)
 489 {
 490         struct hvc_iucv_private *priv;
 491
 492         priv = hvc_iucv_get_private(id);
 493         if (!priv)
 494                 return 0;
 495
 496         spin_lock_bh(&priv->lock);
 497         priv->tty_state = TTY_OPENED;
 498         spin_unlock_bh(&priv->lock);
 499
 500         return 0;
 501 }
 502
 503 /**
 504  * hvc_iucv_cleanup() - Clean up and reset a z/VM IUCV HVC instance.
 505  * @priv:       Pointer to the struct hvc_iucv_private instance.
 506  */
 507 static void hvc_iucv_cleanup(struct hvc_iucv_private *priv)
 508 {
 509         destroy_tty_buffer_list(&priv->tty_outqueue);
 510         destroy_tty_buffer_list(&priv->tty_inqueue);
 511
 512         priv->tty_state = TTY_CLOSED;
 513         priv->iucv_state = IUCV_DISCONN;
 514
 515         priv->sndbuf_len = 0;
 516 }
 517
 518 /**
 519  * tty_outqueue_empty() - Test if the tty outq is empty
 520  * @priv:       Pointer to struct hvc_iucv_private instance.
 521  */
 522 static inline int tty_outqueue_empty(struct hvc_iucv_private *priv)
 523 {
 524         int rc;
 525
 526         spin_lock_bh(&priv->lock);
 527         rc = list_empty(&priv->tty_outqueue);
 528         spin_unlock_bh(&priv->lock);
 529
 530         return rc;
 531 }
 532
 533 /**
 534  * flush_sndbuf_sync() - Flush send buffer and wait for completion
 535  * @priv:       Pointer to struct hvc_iucv_private instance.
 536  *
 537  * The routine cancels a pending sndbuf work, calls hvc_iucv_send()
 538  * to flush any buffered terminal output data and waits for completion.
 539  */
 540 static void flush_sndbuf_sync(struct hvc_iucv_private *priv)
 541 {
 542         int sync_wait;
 543
 544         cancel_delayed_work_sync(&priv->sndbuf_work);
 545
 546         spin_lock_bh(&priv->lock);
 547         hvc_iucv_send(priv);            /* force sending buffered data */
 548         sync_wait = !list_empty(&priv->tty_outqueue); /* anything queued ? */
 549         spin_unlock_bh(&priv->lock);
 550
 551         if (sync_wait)
 552                 wait_event_timeout(priv->sndbuf_waitq,
 553                                    tty_outqueue_empty(priv), HZ/10);
 554 }
 555
 556 /**
 557  * hvc_iucv_hangup() - Sever IUCV path and schedule hvc tty hang up
 558  * @priv:       Pointer to hvc_iucv_private structure
 559  *
 560  * This routine severs an existing IUCV communication path and hangs
 561  * up the underlying HVC terminal device.
 562  * The hang-up occurs only if an IUCV communication path is established;
 563  * otherwise there is no need to hang up the terminal device.
 564  *
 565  * The IUCV HVC hang-up is separated into two steps:
 566  * 1. After the IUCV path has been severed, the iucv_state is set to
 567  *    IUCV_SEVERED.
 568  * 2. Later, when the HVC thread calls hvc_iucv_get_chars(), the
 569  *    IUCV_SEVERED state causes the tty hang-up in the HVC layer.
 570  *
 571  * If the tty has not yet been opened, clean up the hvc_iucv_private
 572  * structure to allow re-connects.
 573  * If the tty has been opened, let get_chars() return -EPIPE to signal
 574  * the HVC layer to hang up the tty and, if so, wake up the HVC thread
 575  * to call get_chars()...
 576  *
 577  * Special notes on hanging up a HVC terminal instantiated as console:
 578  * Hang-up:     1. do_tty_hangup() replaces file ops (= hung_up_tty_fops)
 579  *              2. do_tty_hangup() calls tty->ops->close() for console_filp
 580  *                      => no hangup notifier is called by HVC (default)
 581  *              2. hvc_close() returns because of tty_hung_up_p(filp)
 582  *                      => no delete notifier is called!
 583  * Finally, the back-end is not being notified, thus, the tty session is
 584  * kept active (TTY_OPEN) to be ready for re-connects.
 585  *
 586  * Locking:     spin_lock(&priv->lock) w/o disabling bh
 587  */
 588 static void hvc_iucv_hangup(struct hvc_iucv_private *priv)
 589 {
 590         struct iucv_path *path;
 591
 592         path = NULL;
 593         spin_lock(&priv->lock);
 594         if (priv->iucv_state == IUCV_CONNECTED) {
 595                 path = priv->path;
 596                 priv->path = NULL;
 597                 priv->iucv_state = IUCV_SEVERED;
 598                 if (priv->tty_state == TTY_CLOSED)
 599                         hvc_iucv_cleanup(priv);
 600                 else
 601                         /* console is special (see above) */
 602                         if (priv->is_console) {
 603                                 hvc_iucv_cleanup(priv);
 604                                 priv->tty_state = TTY_OPENED;
 605                         } else
 606                                 hvc_kick();
 607         }
 608         spin_unlock(&priv->lock);
 609
 610         /* finally sever path (outside of priv->lock due to lock ordering) */
 611         if (path) {
 612                 iucv_path_sever(path, NULL);
 613                 iucv_path_free(path);
 614         }
 615 }
 616
 617 /**
 618  * hvc_iucv_notifier_hangup() - HVC notifier for TTY hangups.
 619  * @hp:         Pointer to the HVC device (struct hvc_struct)
 620  * @id:         Additional data (originally passed to hvc_alloc):
 621  *              the index of an struct hvc_iucv_private instance.
 622  *
 623  * This routine notifies the HVC back-end that a tty hangup (carrier loss,
 624  * virtual or otherwise) has occurred.
 625  * The z/VM IUCV HVC device driver ignores virtual hangups (vhangup())
 626  * to keep an existing IUCV communication path established.
 627  * (Background: vhangup() is called from user space (by getty or login) to
 628  *              disable writing to the tty by other applications).
 629  * If the tty has been opened and an established IUCV path has been severed
 630  * (we caused the tty hangup), the function calls hvc_iucv_cleanup().
 631  *
 632  * Locking:     struct hvc_iucv_private->lock
 633  */
 634 static void hvc_iucv_notifier_hangup(struct hvc_struct *hp, int id)
 635 {
 636         struct hvc_iucv_private *priv;
 637
 638         priv = hvc_iucv_get_private(id);
 639         if (!priv)
 640                 return;
 641
 642         flush_sndbuf_sync(priv);
 643
 644         spin_lock_bh(&priv->lock);
 645         /* NOTE: If the hangup was scheduled by ourself (from the iucv
 646          *       path_servered callback [IUCV_SEVERED]), we have to clean up
 647          *       our structure and to set state to TTY_CLOSED.
 648          *       If the tty was hung up otherwise (e.g. vhangup()), then we
 649          *       ignore this hangup and keep an established IUCV path open...
 650          *       (...the reason is that we are not able to connect back to the
 651          *       client if we disconnect on hang up) */
 652         priv->tty_state = TTY_CLOSED;
 653
 654         if (priv->iucv_state == IUCV_SEVERED)
 655                 hvc_iucv_cleanup(priv);
 656         spin_unlock_bh(&priv->lock);
 657 }
 658
 659 /**
 660  * hvc_iucv_dtr_rts() - HVC notifier for handling DTR/RTS
 661  * @hp:         Pointer the HVC device (struct hvc_struct)
 662  * @raise:      Non-zero to raise or zero to lower DTR/RTS lines
 663  *
 664  * This routine notifies the HVC back-end to raise or lower DTR/RTS
 665  * lines.  Raising DTR/RTS is ignored.  Lowering DTR/RTS indicates to
 666  * drop the IUCV connection (similar to hang up the modem).
 667  */
 668 static void hvc_iucv_dtr_rts(struct hvc_struct *hp, int raise)
 669 {
 670         struct hvc_iucv_private *priv;
 671         struct iucv_path        *path;
 672
 673         /* Raising the DTR/RTS is ignored as IUCV connections can be
 674          * established at any times.
 675          */
 676         if (raise)
 677                 return;
 678
 679         priv = hvc_iucv_get_private(hp->vtermno);
 680         if (!priv)
 681                 return;
 682
 683         /* Lowering the DTR/RTS lines disconnects an established IUCV
 684          * connection.
 685          */
 686         flush_sndbuf_sync(priv);
 687
 688         spin_lock_bh(&priv->lock);
 689         path = priv->path;              /* save reference to IUCV path */
 690         priv->path = NULL;
 691         priv->iucv_state = IUCV_DISCONN;
 692         spin_unlock_bh(&priv->lock);
 693
 694         /* Sever IUCV path outside of priv->lock due to lock ordering of:
 695          * priv->lock <--> iucv_table_lock */
 696         if (path) {
 697                 iucv_path_sever(path, NULL);
 698                 iucv_path_free(path);
 699         }
 700 }
 701
 702 /**
 703  * hvc_iucv_notifier_del() - HVC notifier for closing a TTY for the last time.
 704  * @hp:         Pointer to the HVC device (struct hvc_struct)
 705  * @id:         Additional data (originally passed to hvc_alloc):
 706  *              the index of an struct hvc_iucv_private instance.
 707  *
 708  * This routine notifies the HVC back-end that the last tty device fd has been
 709  * closed.  The function cleans up tty resources.  The clean-up of the IUCV
 710  * connection is done in hvc_iucv_dtr_rts() and depends on the HUPCL termios
 711  * control setting.
 712  *
 713  * Locking:     struct hvc_iucv_private->lock
 714  */
 715 static void hvc_iucv_notifier_del(struct hvc_struct *hp, int id)
 716 {
 717         struct hvc_iucv_private *priv;
 718
 719         priv = hvc_iucv_get_private(id);
 720         if (!priv)
 721                 return;
 722
 723         flush_sndbuf_sync(priv);
 724
 725         spin_lock_bh(&priv->lock);
 726         destroy_tty_buffer_list(&priv->tty_outqueue);
 727         destroy_tty_buffer_list(&priv->tty_inqueue);
 728         priv->tty_state = TTY_CLOSED;
 729         priv->sndbuf_len = 0;
 730         spin_unlock_bh(&priv->lock);
 731 }
 732
 733 /**
 734  * hvc_iucv_filter_connreq() - Filter connection request based on z/VM user ID
 735  * @ipvmid:     Originating z/VM user ID (right padded with blanks)
 736  *
 737  * Returns 0 if the z/VM user ID that is specified with @ipvmid is permitted to
 738  * connect, otherwise non-zero.
 739  */
 740 static int hvc_iucv_filter_connreq(u8 ipvmid[8])
 741 {
 742         const char *wildcard, *filter_entry;
 743         size_t i, len;
 744
 745         /* Note: default policy is ACCEPT if no filter is set */
 746         if (!hvc_iucv_filter_size)
 747                 return 0;
 748
 749         for (i = 0; i < hvc_iucv_filter_size; i++) {
 750                 filter_entry = hvc_iucv_filter + (8 * i);
 751
 752                 /* If a filter entry contains the filter wildcard character,
 753                  * reduce the length to match the leading portion of the user
 754                  * ID only (wildcard match).  Characters following the wildcard
 755                  * are ignored.
 756                  */
 757                 wildcard = strnchr(filter_entry, 8, FILTER_WILDCARD_CHAR);
 758                 len = (wildcard) ? wildcard - filter_entry : 8;
 759                 if (0 == memcmp(ipvmid, filter_entry, len))
 760                         return 0;
 761         }
 762         return 1;
 763 }
 764
 765 /**
 766  * hvc_iucv_path_pending() - IUCV handler to process a connection request.
 767  * @path:       Pending path (struct iucv_path)
 768  * @ipvmid:     z/VM system identifier of originator
 769  * @ipuser:     User specified data for this path
 770  *              (AF_IUCV: port/service name and originator port)
 771  *
 772  * The function uses the @ipuser data to determine if the pending path belongs
 773  * to a terminal managed by this device driver.
 774  * If the path belongs to this driver, ensure that the terminal is not accessed
 775  * multiple times (only one connection to a terminal is allowed).
 776  * If the terminal is not yet connected, the pending path is accepted and is
 777  * associated to the appropriate struct hvc_iucv_private instance.
 778  *
 779  * Returns 0 if @path belongs to a terminal managed by the this device driver;
 780  * otherwise returns -ENODEV in order to dispatch this path to other handlers.
 781  *
 782  * Locking:     struct hvc_iucv_private->lock
 783  */
 784 static  int hvc_iucv_path_pending(struct iucv_path *path, u8 *ipvmid,
 785                                   u8 *ipuser)
 786 {
 787         struct hvc_iucv_private *priv, *tmp;
 788         u8 wildcard[9] = "lnxhvc  ";
 789         int i, rc, find_unused;
 790         u8 nuser_data[16];
 791         u8 vm_user_id[9];
 792
 793         ASCEBC(wildcard, sizeof(wildcard));
 794         find_unused = !memcmp(wildcard, ipuser, 8);
 795
 796         /* First, check if the pending path request is managed by this
 797          * IUCV handler:
 798          * - find a disconnected device if ipuser contains the wildcard
 799          * - find the device that matches the terminal ID in ipuser
 800          */
 801         priv = NULL;
 802         for (i = 0; i < hvc_iucv_devices; i++) {
 803                 tmp = hvc_iucv_table[i];
 804                 if (!tmp)
 805                         continue;
 806
 807                 if (find_unused) {
 808                         spin_lock(&tmp->lock);
 809                         if (tmp->iucv_state == IUCV_DISCONN)
 810                                 priv = tmp;
 811                         spin_unlock(&tmp->lock);
 812
 813                 } else if (!memcmp(tmp->srv_name, ipuser, 8))
 814                                 priv = tmp;
 815                 if (priv)
 816                         break;
 817         }
 818         if (!priv)
 819                 return -ENODEV;
 820
 821         /* Enforce that ipvmid is allowed to connect to us */
 822         read_lock(&hvc_iucv_filter_lock);
 823         rc = hvc_iucv_filter_connreq(ipvmid);
 824         read_unlock(&hvc_iucv_filter_lock);
 825         if (rc) {
 826                 iucv_path_sever(path, ipuser);
 827                 iucv_path_free(path);
 828                 memcpy(vm_user_id, ipvmid, 8);
 829                 vm_user_id[8] = 0;
 830                 pr_info("A connection request from z/VM user ID %s "
 831                         "was refused\n", vm_user_id);
 832                 return 0;
 833         }
 834
 835         spin_lock(&priv->lock);
 836
 837         /* If the terminal is already connected or being severed, then sever
 838          * this path to enforce that there is only ONE established communication
 839          * path per terminal. */
 840         if (priv->iucv_state != IUCV_DISCONN) {
 841                 iucv_path_sever(path, ipuser);
 842                 iucv_path_free(path);
 843                 goto out_path_handled;
 844         }
 845
 846         /* accept path */
 847         memcpy(nuser_data, ipuser + 8, 8);  /* remote service (for af_iucv) */
 848         memcpy(nuser_data + 8, ipuser, 8);  /* local service  (for af_iucv) */
 849         path->msglim = 0xffff;              /* IUCV MSGLIMIT */
 850         path->flags &= ~IUCV_IPRMDATA;      /* TODO: use IUCV_IPRMDATA */
 851         rc = iucv_path_accept(path, &hvc_iucv_handler, nuser_data, priv);
 852         if (rc) {
 853                 iucv_path_sever(path, ipuser);
 854                 iucv_path_free(path);
 855                 goto out_path_handled;
 856         }
 857         priv->path = path;
 858         priv->iucv_state = IUCV_CONNECTED;
 859
 860         /* store path information */
 861         memcpy(priv->info_path, ipvmid, 8);
 862         memcpy(priv->info_path + 8, ipuser + 8, 8);
 863
 864         /* flush buffered output data... */
 865         schedule_delayed_work(&priv->sndbuf_work, 5);
 866
 867 out_path_handled:
 868         spin_unlock(&priv->lock);
 869         return 0;
 870 }
 871
 872 /**
 873  * hvc_iucv_path_severed() - IUCV handler to process a path sever.
 874  * @path:       Pending path (struct iucv_path)
 875  * @ipuser:     User specified data for this path
 876  *              (AF_IUCV: port/service name and originator port)
 877  *
 878  * This function calls the hvc_iucv_hangup() function for the
 879  * respective IUCV HVC terminal.
 880  *
 881  * Locking:     struct hvc_iucv_private->lock
 882  */
 883 static void hvc_iucv_path_severed(struct iucv_path *path, u8 *ipuser)
 884 {
 885         struct hvc_iucv_private *priv = path->private;
 886
 887         hvc_iucv_hangup(priv);
 888 }
 889
 890 /**
 891  * hvc_iucv_msg_pending() - IUCV handler to process an incoming IUCV message.
 892  * @path:       Pending path (struct iucv_path)
 893  * @msg:        Pointer to the IUCV message
 894  *
 895  * The function puts an incoming message on the input queue for later
 896  * processing (by hvc_iucv_get_chars() / hvc_iucv_write()).
 897  * If the tty has not yet been opened, the message is rejected.
 898  *
 899  * Locking:     struct hvc_iucv_private->lock
 900  */
 901 static void hvc_iucv_msg_pending(struct iucv_path *path,
 902                                  struct iucv_message *msg)
 903 {
 904         struct hvc_iucv_private *priv = path->private;
 905         struct iucv_tty_buffer *rb;
 906
 907         /* reject messages that exceed max size of iucv_tty_msg->datalen */
 908         if (msg->length > MSG_SIZE(MSG_MAX_DATALEN)) {
 909                 iucv_message_reject(path, msg);
 910                 return;
 911         }
 912
 913         spin_lock(&priv->lock);
 914
 915         /* reject messages if tty has not yet been opened */
 916         if (priv->tty_state == TTY_CLOSED) {
 917                 iucv_message_reject(path, msg);
 918                 goto unlock_return;
 919         }
 920
 921         /* allocate tty buffer to save iucv msg only */
 922         rb = alloc_tty_buffer(0, GFP_ATOMIC);
 923         if (!rb) {
 924                 iucv_message_reject(path, msg);
 925                 goto unlock_return;     /* -ENOMEM */
 926         }
 927         rb->msg = *msg;
 928
 929         list_add_tail(&rb->list, &priv->tty_inqueue);
 930
 931         hvc_kick();     /* wake up hvc thread */
 932
 933 unlock_return:
 934         spin_unlock(&priv->lock);
 935 }
 936
 937 /**
 938  * hvc_iucv_msg_complete() - IUCV handler to process message completion
 939  * @path:       Pending path (struct iucv_path)
 940  * @msg:        Pointer to the IUCV message
 941  *
 942  * The function is called upon completion of message delivery to remove the
 943  * message from the outqueue. Additional delivery information can be found
 944  * msg->audit: rejected messages (0x040000 (IPADRJCT)), and
 945  *             purged messages   (0x010000 (IPADPGNR)).
 946  *
 947  * Locking:     struct hvc_iucv_private->lock
 948  */
 949 static void hvc_iucv_msg_complete(struct iucv_path *path,
 950                                   struct iucv_message *msg)
 951 {
 952         struct hvc_iucv_private *priv = path->private;
 953         struct iucv_tty_buffer  *ent, *next;
 954         LIST_HEAD(list_remove);
 955
 956         spin_lock(&priv->lock);
 957         list_for_each_entry_safe(ent, next, &priv->tty_outqueue, list)
 958                 if (ent->msg.id == msg->id) {
 959                         list_move(&ent->list, &list_remove);
 960                         break;
 961                 }
 962         wake_up(&priv->sndbuf_waitq);
 963         spin_unlock(&priv->lock);
 964         destroy_tty_buffer_list(&list_remove);
 965 }
 966
 967 static ssize_t hvc_iucv_dev_termid_show(struct device *dev,
 968                                         struct device_attribute *attr,
 969                                         char *buf)
 970 {
 971         struct hvc_iucv_private *priv = dev_get_drvdata(dev);
 972         size_t len;
 973
 974         len = sizeof(priv->srv_name);
 975         memcpy(buf, priv->srv_name, len);
 976         EBCASC(buf, len);
 977         buf[len++] = '\n';
 978         return len;
 979 }
 980
 981 static ssize_t hvc_iucv_dev_state_show(struct device *dev,
 982                                         struct device_attribute *attr,
 983                                         char *buf)
 984 {
 985         struct hvc_iucv_private *priv = dev_get_drvdata(dev);
 986         return sprintf(buf, "%u:%u\n", priv->iucv_state, priv->tty_state);
 987 }
 988
 989 static ssize_t hvc_iucv_dev_peer_show(struct device *dev,
 990                                       struct device_attribute *attr,
 991                                       char *buf)
 992 {
 993         struct hvc_iucv_private *priv = dev_get_drvdata(dev);
 994         char vmid[9], ipuser[9];
 995
 996         memset(vmid, 0, sizeof(vmid));
 997         memset(ipuser, 0, sizeof(ipuser));
 998
 999         spin_lock_bh(&priv->lock);
1000         if (priv->iucv_state == IUCV_CONNECTED) {
1001                 memcpy(vmid, priv->info_path, 8);
1002                 memcpy(ipuser, priv->info_path + 8, 8);
1003         }
1004         spin_unlock_bh(&priv->lock);
1005         EBCASC(ipuser, 8);
1006
1007         return sprintf(buf, "%s:%s\n", vmid, ipuser);
1008 }
1009
1010
1011 /* HVC operations */
1012 static const struct hv_ops hvc_iucv_ops = {
1013         .get_chars = hvc_iucv_get_chars,
1014         .put_chars = hvc_iucv_put_chars,
1015         .notifier_add = hvc_iucv_notifier_add,
1016         .notifier_del = hvc_iucv_notifier_del,
1017         .notifier_hangup = hvc_iucv_notifier_hangup,
1018         .dtr_rts = hvc_iucv_dtr_rts,
1019 };
1020
1021 /* IUCV HVC device attributes */
1022 static DEVICE_ATTR(termid, 0640, hvc_iucv_dev_termid_show, NULL);
1023 static DEVICE_ATTR(state, 0640, hvc_iucv_dev_state_show, NULL);
1024 static DEVICE_ATTR(peer, 0640, hvc_iucv_dev_peer_show, NULL);
1025 static struct attribute *hvc_iucv_dev_attrs[] = {
1026         &dev_attr_termid.attr,
1027         &dev_attr_state.attr,
1028         &dev_attr_peer.attr,
1029         NULL,
1030 };
1031 static struct attribute_group hvc_iucv_dev_attr_group = {
1032         .attrs = hvc_iucv_dev_attrs,
1033 };
1034 static const struct attribute_group *hvc_iucv_dev_attr_groups[] = {
1035         &hvc_iucv_dev_attr_group,
1036         NULL,
1037 };
1038
1039
1040 /**
1041  * hvc_iucv_alloc() - Allocates a new struct hvc_iucv_private instance
1042  * @id:                 hvc_iucv_table index
1043  * @is_console:         Flag if the instance is used as Linux console
1044  *
1045  * This function allocates a new hvc_iucv_private structure and stores
1046  * the instance in hvc_iucv_table at index @id.
1047  * Returns 0 on success; otherwise non-zero.
1048  */
1049 static int __init hvc_iucv_alloc(int id, unsigned int is_console)
1050 {
1051         struct hvc_iucv_private *priv;
1052         char name[9];
1053         int rc;
1054
1055         priv = kzalloc(sizeof(struct hvc_iucv_private), GFP_KERNEL);
1056         if (!priv)
1057                 return -ENOMEM;
1058
1059         spin_lock_init(&priv->lock);
1060         INIT_LIST_HEAD(&priv->tty_outqueue);
1061         INIT_LIST_HEAD(&priv->tty_inqueue);
1062         INIT_DELAYED_WORK(&priv->sndbuf_work, hvc_iucv_sndbuf_work);
1063         init_waitqueue_head(&priv->sndbuf_waitq);
1064
1065         priv->sndbuf = (void *) get_zeroed_page(GFP_KERNEL);
1066         if (!priv->sndbuf) {
1067                 kfree(priv);
1068                 return -ENOMEM;
1069         }
1070
1071         /* set console flag */
1072         priv->is_console = is_console;
1073
1074         /* allocate hvc device */
1075         priv->hvc = hvc_alloc(HVC_IUCV_MAGIC + id, /*             PAGE_SIZE */
1076                               HVC_IUCV_MAGIC + id, &hvc_iucv_ops, 256);
1077         if (IS_ERR(priv->hvc)) {
1078                 rc = PTR_ERR(priv->hvc);
1079                 goto out_error_hvc;
1080         }
1081
1082         /* notify HVC thread instead of using polling */
1083         priv->hvc->irq_requested = 1;
1084
1085         /* setup iucv related information */
1086         snprintf(name, 9, "lnxhvc%-2d", id);
1087         memcpy(priv->srv_name, name, 8);
1088         ASCEBC(priv->srv_name, 8);
1089
1090         /* create and setup device */
1091         priv->dev = kzalloc(sizeof(*priv->dev), GFP_KERNEL);
1092         if (!priv->dev) {
1093                 rc = -ENOMEM;
1094                 goto out_error_dev;
1095         }
1096         dev_set_name(priv->dev, "hvc_iucv%d", id);
1097         dev_set_drvdata(priv->dev, priv);
1098         priv->dev->bus = &iucv_bus;
1099         priv->dev->parent = iucv_root;
1100         priv->dev->groups = hvc_iucv_dev_attr_groups;
1101         priv->dev->release = (void (*)(struct device *)) kfree;
1102         rc = device_register(priv->dev);
1103         if (rc) {
1104                 put_device(priv->dev);
1105                 goto out_error_dev;
1106         }
1107
1108         hvc_iucv_table[id] = priv;
1109         return 0;
1110
1111 out_error_dev:
1112         hvc_remove(priv->hvc);
1113 out_error_hvc:
1114         free_page((unsigned long) priv->sndbuf);
1115         kfree(priv);
1116
1117         return rc;
1118 }
1119
1120 /**
1121  * hvc_iucv_destroy() - Destroy and free hvc_iucv_private instances
1122  */
1123 static void __init hvc_iucv_destroy(struct hvc_iucv_private *priv)
1124 {
1125         hvc_remove(priv->hvc);
1126         device_unregister(priv->dev);
1127         free_page((unsigned long) priv->sndbuf);
1128         kfree(priv);
1129 }
1130
1131 /**
1132  * hvc_iucv_parse_filter() - Parse filter for a single z/VM user ID
1133  * @filter:     String containing a comma-separated list of z/VM user IDs
1134  * @dest:       Location where to store the parsed z/VM user ID
1135  */
1136 static const char *hvc_iucv_parse_filter(const char *filter, char *dest)
1137 {
1138         const char *nextdelim, *residual;
1139         size_t len;
1140
1141         nextdelim = strchr(filter, ',');
1142         if (nextdelim) {
1143                 len = nextdelim - filter;
1144                 residual = nextdelim + 1;
1145         } else {
1146                 len = strlen(filter);
1147                 residual = filter + len;
1148         }
1149
1150         if (len == 0)
1151                 return ERR_PTR(-EINVAL);
1152
1153         /* check for '\n' (if called from sysfs) */
1154         if (filter[len - 1] == '\n')
1155                 len--;
1156
1157         /* prohibit filter entries containing the wildcard character only */
1158         if (len == 1 && *filter == FILTER_WILDCARD_CHAR)
1159                 return ERR_PTR(-EINVAL);
1160
1161         if (len > 8)
1162                 return ERR_PTR(-EINVAL);
1163
1164         /* pad with blanks and save upper case version of user ID */
1165         memset(dest, ' ', 8);
1166         while (len--)
1167                 dest[len] = toupper(filter[len]);
1168         return residual;
1169 }
1170
1171 /**
1172  * hvc_iucv_setup_filter() - Set up z/VM user ID filter
1173  * @filter:     String consisting of a comma-separated list of z/VM user IDs
1174  *
1175  * The function parses the @filter string and creates an array containing
1176  * the list of z/VM user ID filter entries.
1177  * Return code 0 means success, -EINVAL if the filter is syntactically
1178  * incorrect, -ENOMEM if there was not enough memory to allocate the
1179  * filter list array, or -ENOSPC if too many z/VM user IDs have been specified.
1180  */
1181 static int hvc_iucv_setup_filter(const char *val)
1182 {
1183         const char *residual;
1184         int err;
1185         size_t size, count;
1186         void *array, *old_filter;
1187
1188         count = strlen(val);
1189         if (count == 0 || (count == 1 && val[0] == '\n')) {
1190                 size  = 0;
1191                 array = NULL;
1192                 goto out_replace_filter;        /* clear filter */
1193         }
1194
1195         /* count user IDs in order to allocate sufficient memory */
1196         size = 1;
1197         residual = val;
1198         while ((residual = strchr(residual, ',')) != NULL) {
1199                 residual++;
1200                 size++;
1201         }
1202
1203         /* check if the specified list exceeds the filter limit */
1204         if (size > MAX_VMID_FILTER)
1205                 return -ENOSPC;
1206
1207         array = kcalloc(size, 8, GFP_KERNEL);
1208         if (!array)
1209                 return -ENOMEM;
1210
1211         count = size;
1212         residual = val;
1213         while (*residual && count) {
1214                 residual = hvc_iucv_parse_filter(residual,
1215                                                  array + ((size - count) * 8));
1216                 if (IS_ERR(residual)) {
1217                         err = PTR_ERR(residual);
1218                         kfree(array);
1219                         goto out_err;
1220                 }
1221                 count--;
1222         }
1223
1224 out_replace_filter:
1225         write_lock_bh(&hvc_iucv_filter_lock);
1226         old_filter = hvc_iucv_filter;
1227         hvc_iucv_filter_size = size;
1228         hvc_iucv_filter = array;
1229         write_unlock_bh(&hvc_iucv_filter_lock);
1230         kfree(old_filter);
1231
1232         err = 0;
1233 out_err:
1234         return err;
1235 }
1236
1237 /**
1238  * param_set_vmidfilter() - Set z/VM user ID filter parameter
1239  * @val:        String consisting of a comma-separated list of z/VM user IDs
1240  * @kp:         Kernel parameter pointing to hvc_iucv_filter array
1241  *
1242  * The function sets up the z/VM user ID filter specified as comma-separated
1243  * list of user IDs in @val.
1244  * Note: If it is called early in the boot process, @val is stored and
1245  *       parsed later in hvc_iucv_init().
1246  */
1247 static int param_set_vmidfilter(const char *val, const struct kernel_param *kp)
1248 {
1249         int rc;
1250
1251         if (!MACHINE_IS_VM || !hvc_iucv_devices)
1252                 return -ENODEV;
1253
1254         if (!val)
1255                 return -EINVAL;
1256
1257         rc = 0;
1258         if (slab_is_available())
1259                 rc = hvc_iucv_setup_filter(val);
1260         else
1261                 hvc_iucv_filter_string = val;   /* defer... */
1262         return rc;
1263 }
1264
1265 /**
1266  * param_get_vmidfilter() - Get z/VM user ID filter
1267  * @buffer:     Buffer to store z/VM user ID filter,
1268  *              (buffer size assumption PAGE_SIZE)
1269  * @kp:         Kernel parameter pointing to the hvc_iucv_filter array
1270  *
1271  * The function stores the filter as a comma-separated list of z/VM user IDs
1272  * in @buffer. Typically, sysfs routines call this function for attr show.
1273  */
1274 static int param_get_vmidfilter(char *buffer, const struct kernel_param *kp)
1275 {
1276         int rc;
1277         size_t index, len;
1278         void *start, *end;
1279
1280         if (!MACHINE_IS_VM || !hvc_iucv_devices)
1281                 return -ENODEV;
1282
1283         rc = 0;
1284         read_lock_bh(&hvc_iucv_filter_lock);
1285         for (index = 0; index < hvc_iucv_filter_size; index++) {
1286                 start = hvc_iucv_filter + (8 * index);
1287                 end   = memchr(start, ' ', 8);
1288                 len   = (end) ? end - start : 8;
1289                 memcpy(buffer + rc, start, len);
1290                 rc += len;
1291                 buffer[rc++] = ',';
1292         }
1293         read_unlock_bh(&hvc_iucv_filter_lock);
1294         if (rc)
1295                 buffer[--rc] = '\0';    /* replace last comma and update rc */
1296         return rc;
1297 }
1298
1299 #define param_check_vmidfilter(name, p) __param_check(name, p, void)
1300
1301 static const struct kernel_param_ops param_ops_vmidfilter = {
1302         .set = param_set_vmidfilter,
1303         .get = param_get_vmidfilter,
1304 };
1305
1306 /**
1307  * hvc_iucv_init() - z/VM IUCV HVC device driver initialization
1308  */
1309 static int __init hvc_iucv_init(void)
1310 {
1311         int rc;
1312         unsigned int i;
1313
1314         if (!hvc_iucv_devices)
1315                 return -ENODEV;
1316
1317         if (!MACHINE_IS_VM) {
1318                 pr_notice("The z/VM IUCV HVC device driver cannot "
1319                            "be used without z/VM\n");
1320                 rc = -ENODEV;
1321                 goto out_error;
1322         }
1323
1324         if (hvc_iucv_devices > MAX_HVC_IUCV_LINES) {
1325                 pr_err("%lu is not a valid value for the hvc_iucv= "
1326                         "kernel parameter\n", hvc_iucv_devices);
1327                 rc = -EINVAL;
1328                 goto out_error;
1329         }
1330
1331         /* parse hvc_iucv_allow string and create z/VM user ID filter list */
1332         if (hvc_iucv_filter_string) {
1333                 rc = hvc_iucv_setup_filter(hvc_iucv_filter_string);
1334                 switch (rc) {
1335                 case 0:
1336                         break;
1337                 case -ENOMEM:
1338                         pr_err("Allocating memory failed with "
1339                                 "reason code=%d\n", 3);
1340                         goto out_error;
1341                 case -EINVAL:
1342                         pr_err("hvc_iucv_allow= does not specify a valid "
1343                                 "z/VM user ID list\n");
1344                         goto out_error;
1345                 case -ENOSPC:
1346                         pr_err("hvc_iucv_allow= specifies too many "
1347                                 "z/VM user IDs\n");
1348                         goto out_error;
1349                 default:
1350                         goto out_error;
1351                 }
1352         }
1353
1354         hvc_iucv_buffer_cache = kmem_cache_create(KMSG_COMPONENT,
1355                                            sizeof(struct iucv_tty_buffer),
1356                                            0, 0, NULL);
1357         if (!hvc_iucv_buffer_cache) {
1358                 pr_err("Allocating memory failed with reason code=%d\n", 1);
1359                 rc = -ENOMEM;
1360                 goto out_error;
1361         }
1362
1363         hvc_iucv_mempool = mempool_create_slab_pool(MEMPOOL_MIN_NR,
1364                                                     hvc_iucv_buffer_cache);
1365         if (!hvc_iucv_mempool) {
1366                 pr_err("Allocating memory failed with reason code=%d\n", 2);
1367                 kmem_cache_destroy(hvc_iucv_buffer_cache);
1368                 rc = -ENOMEM;
1369                 goto out_error;
1370         }
1371
1372         /* register the first terminal device as console
1373          * (must be done before allocating hvc terminal devices) */
1374         rc = hvc_instantiate(HVC_IUCV_MAGIC, IUCV_HVC_CON_IDX, &hvc_iucv_ops);
1375         if (rc) {
1376                 pr_err("Registering HVC terminal device as "
1377                        "Linux console failed\n");
1378                 goto out_error_memory;
1379         }
1380
1381         /* allocate hvc_iucv_private structs */
1382         for (i = 0; i < hvc_iucv_devices; i++) {
1383                 rc = hvc_iucv_alloc(i, (i == IUCV_HVC_CON_IDX) ? 1 : 0);
1384                 if (rc) {
1385                         pr_err("Creating a new HVC terminal device "
1386                                 "failed with error code=%d\n", rc);
1387                         goto out_error_hvc;
1388                 }
1389         }
1390
1391         /* register IUCV callback handler */
1392         rc = iucv_register(&hvc_iucv_handler, 0);
1393         if (rc) {
1394                 pr_err("Registering IUCV handlers failed with error code=%d\n",
1395                         rc);
1396                 goto out_error_hvc;
1397         }
1398
1399         return 0;
1400
1401 out_error_hvc:
1402         for (i = 0; i < hvc_iucv_devices; i++)
1403                 if (hvc_iucv_table[i])
1404                         hvc_iucv_destroy(hvc_iucv_table[i]);
1405 out_error_memory:
1406         mempool_destroy(hvc_iucv_mempool);
1407         kmem_cache_destroy(hvc_iucv_buffer_cache);
1408 out_error:
1409         kfree(hvc_iucv_filter);
1410         hvc_iucv_devices = 0; /* ensure that we do not provide any device */
1411         return rc;
1412 }
1413
1414 /**
1415  * hvc_iucv_config() - Parsing of hvc_iucv=  kernel command line parameter
1416  * @val:        Parameter value (numeric)
1417  */
1418 static  int __init hvc_iucv_config(char *val)
1419 {
1420          return kstrtoul(val, 10, &hvc_iucv_devices);
1421 }
1422
1423
1424 device_initcall(hvc_iucv_init);
1425 __setup("hvc_iucv=", hvc_iucv_config);
1426 core_param(hvc_iucv_allow, hvc_iucv_filter, vmidfilter, 0640);