drivers/tty/hvc/hvc_iucv.c

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