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
  44struct 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
  53enum iucv_state_t {
  54	IUCV_DISCONN	= 0,
  55	IUCV_CONNECTED	= 1,
  56	IUCV_SEVERED	= 2,
  57};
  58
  59enum tty_state_t {
  60	TTY_CLOSED	= 0,
  61	TTY_OPENED	= 1,
  62};
  63
  64struct 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
  84struct 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 */
  92static	int hvc_iucv_path_pending(struct iucv_path *, u8 *, u8 *);
  93static void hvc_iucv_path_severed(struct iucv_path *, u8 *);
  94static void hvc_iucv_msg_pending(struct iucv_path *, struct iucv_message *);
  95static void hvc_iucv_msg_complete(struct iucv_path *, struct iucv_message *);
  96
  97
  98/* Kernel module parameter: use one terminal device as default */
  99static unsigned long hvc_iucv_devices = 1;
 100
 101/* Array of allocated hvc iucv tty lines... */
 102static 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	'*'
 107static size_t hvc_iucv_filter_size;
 108static void *hvc_iucv_filter;
 109static const char *hvc_iucv_filter_string;
 110static DEFINE_RWLOCK(hvc_iucv_filter_lock);
 111
 112/* Kmem cache and mempool for iucv_tty_buffer elements */
 113static struct kmem_cache *hvc_iucv_buffer_cache;
 114static mempool_t *hvc_iucv_mempool;
 115
 116/* IUCV handler callback functions */
 117static 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 */
 132static 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 */
 152static 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 */
 179static 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 */
 189static 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 */
 219static 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
 293out_remove_buffer:
 294	list_del(&rb->list);
 295	destroy_tty_buffer(rb);
 296	*has_more_data = !list_empty(&priv->tty_inqueue);
 297
 298out_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 */
 316static 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 */
 356static 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 */
 389static 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 */
 436static void hvc_iucv_sndbuf_work(struct work_struct *work)
 437{
 438	struct hvc_iucv_private *priv;
 439
 440	priv = container_of(work, struct hvc_iucv_private, sndbuf_work.work);
 441	if (!priv)
 442		return;
 443
 444	spin_lock_bh(&priv->lock);
 445	hvc_iucv_send(priv);
 446	spin_unlock_bh(&priv->lock);
 447}
 448
 449/**
 450 * hvc_iucv_put_chars() - HVC put_chars operation.
 451 * @vtermno:	HVC virtual terminal number.
 452 * @buf:	Pointer to an buffer to read data from
 453 * @count:	Size of buffer available for reading
 454 *
 455 * The HVC thread calls this method to write characters to the back-end.
 456 * The function calls hvc_iucv_queue() to queue terminal data for sending.
 457 *
 458 * Locking:	The method gets called under an irqsave() spinlock; and
 459 *		locks struct hvc_iucv_private->lock.
 460 */
 461static int hvc_iucv_put_chars(uint32_t vtermno, const char *buf, int count)
 462{
 463	struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 464	int queued;
 465
 466	if (count <= 0)
 467		return 0;
 468
 469	if (!priv)
 470		return -ENODEV;
 471
 472	spin_lock(&priv->lock);
 473	queued = hvc_iucv_queue(priv, buf, count);
 474	spin_unlock(&priv->lock);
 475
 476	return queued;
 477}
 478
 479/**
 480 * hvc_iucv_notifier_add() - HVC notifier for opening a TTY for the first time.
 481 * @hp:	Pointer to the HVC device (struct hvc_struct)
 482 * @id:	Additional data (originally passed to hvc_alloc): the index of an struct
 483 *	hvc_iucv_private instance.
 484 *
 485 * The function sets the tty state to TTY_OPENED for the struct hvc_iucv_private
 486 * instance that is derived from @id. Always returns 0.
 487 *
 488 * Locking:	struct hvc_iucv_private->lock, spin_lock_bh
 489 */
 490static int hvc_iucv_notifier_add(struct hvc_struct *hp, int id)
 491{
 492	struct hvc_iucv_private *priv;
 493
 494	priv = hvc_iucv_get_private(id);
 495	if (!priv)
 496		return 0;
 497
 498	spin_lock_bh(&priv->lock);
 499	priv->tty_state = TTY_OPENED;
 500	spin_unlock_bh(&priv->lock);
 501
 502	return 0;
 503}
 504
 505/**
 506 * hvc_iucv_cleanup() - Clean up and reset a z/VM IUCV HVC instance.
 507 * @priv:	Pointer to the struct hvc_iucv_private instance.
 508 */
 509static void hvc_iucv_cleanup(struct hvc_iucv_private *priv)
 510{
 511	destroy_tty_buffer_list(&priv->tty_outqueue);
 512	destroy_tty_buffer_list(&priv->tty_inqueue);
 513
 514	priv->tty_state = TTY_CLOSED;
 515	priv->iucv_state = IUCV_DISCONN;
 516
 517	priv->sndbuf_len = 0;
 518}
 519
 520/**
 521 * tty_outqueue_empty() - Test if the tty outq is empty
 522 * @priv:	Pointer to struct hvc_iucv_private instance.
 523 */
 524static inline int tty_outqueue_empty(struct hvc_iucv_private *priv)
 525{
 526	int rc;
 527
 528	spin_lock_bh(&priv->lock);
 529	rc = list_empty(&priv->tty_outqueue);
 530	spin_unlock_bh(&priv->lock);
 531
 532	return rc;
 533}
 534
 535/**
 536 * flush_sndbuf_sync() - Flush send buffer and wait for completion
 537 * @priv:	Pointer to struct hvc_iucv_private instance.
 538 *
 539 * The routine cancels a pending sndbuf work, calls hvc_iucv_send()
 540 * to flush any buffered terminal output data and waits for completion.
 541 */
 542static void flush_sndbuf_sync(struct hvc_iucv_private *priv)
 543{
 544	int sync_wait;
 545
 546	cancel_delayed_work_sync(&priv->sndbuf_work);
 547
 548	spin_lock_bh(&priv->lock);
 549	hvc_iucv_send(priv);		/* force sending buffered data */
 550	sync_wait = !list_empty(&priv->tty_outqueue); /* anything queued ? */
 551	spin_unlock_bh(&priv->lock);
 552
 553	if (sync_wait)
 554		wait_event_timeout(priv->sndbuf_waitq,
 555				   tty_outqueue_empty(priv), HZ/10);
 556}
 557
 558/**
 559 * hvc_iucv_hangup() - Sever IUCV path and schedule hvc tty hang up
 560 * @priv:	Pointer to hvc_iucv_private structure
 561 *
 562 * This routine severs an existing IUCV communication path and hangs
 563 * up the underlying HVC terminal device.
 564 * The hang-up occurs only if an IUCV communication path is established;
 565 * otherwise there is no need to hang up the terminal device.
 566 *
 567 * The IUCV HVC hang-up is separated into two steps:
 568 * 1. After the IUCV path has been severed, the iucv_state is set to
 569 *    IUCV_SEVERED.
 570 * 2. Later, when the HVC thread calls hvc_iucv_get_chars(), the
 571 *    IUCV_SEVERED state causes the tty hang-up in the HVC layer.
 572 *
 573 * If the tty has not yet been opened, clean up the hvc_iucv_private
 574 * structure to allow re-connects.
 575 * If the tty has been opened, let get_chars() return -EPIPE to signal
 576 * the HVC layer to hang up the tty and, if so, wake up the HVC thread
 577 * to call get_chars()...
 578 *
 579 * Special notes on hanging up a HVC terminal instantiated as console:
 580 * Hang-up:	1. do_tty_hangup() replaces file ops (= hung_up_tty_fops)
 581 *		2. do_tty_hangup() calls tty->ops->close() for console_filp
 582 *			=> no hangup notifier is called by HVC (default)
 583 *		2. hvc_close() returns because of tty_hung_up_p(filp)
 584 *			=> no delete notifier is called!
 585 * Finally, the back-end is not being notified, thus, the tty session is
 586 * kept active (TTY_OPEN) to be ready for re-connects.
 587 *
 588 * Locking:	spin_lock(&priv->lock) w/o disabling bh
 589 */
 590static void hvc_iucv_hangup(struct hvc_iucv_private *priv)
 591{
 592	struct iucv_path *path;
 593
 594	path = NULL;
 595	spin_lock(&priv->lock);
 596	if (priv->iucv_state == IUCV_CONNECTED) {
 597		path = priv->path;
 598		priv->path = NULL;
 599		priv->iucv_state = IUCV_SEVERED;
 600		if (priv->tty_state == TTY_CLOSED)
 601			hvc_iucv_cleanup(priv);
 602		else
 603			/* console is special (see above) */
 604			if (priv->is_console) {
 605				hvc_iucv_cleanup(priv);
 606				priv->tty_state = TTY_OPENED;
 607			} else
 608				hvc_kick();
 609	}
 610	spin_unlock(&priv->lock);
 611
 612	/* finally sever path (outside of priv->lock due to lock ordering) */
 613	if (path) {
 614		iucv_path_sever(path, NULL);
 615		iucv_path_free(path);
 616	}
 617}
 618
 619/**
 620 * hvc_iucv_notifier_hangup() - HVC notifier for TTY hangups.
 621 * @hp:		Pointer to the HVC device (struct hvc_struct)
 622 * @id:		Additional data (originally passed to hvc_alloc):
 623 *		the index of an struct hvc_iucv_private instance.
 624 *
 625 * This routine notifies the HVC back-end that a tty hangup (carrier loss,
 626 * virtual or otherwise) has occurred.
 627 * The z/VM IUCV HVC device driver ignores virtual hangups (vhangup())
 628 * to keep an existing IUCV communication path established.
 629 * (Background: vhangup() is called from user space (by getty or login) to
 630 *		disable writing to the tty by other applications).
 631 * If the tty has been opened and an established IUCV path has been severed
 632 * (we caused the tty hangup), the function calls hvc_iucv_cleanup().
 633 *
 634 * Locking:	struct hvc_iucv_private->lock
 635 */
 636static void hvc_iucv_notifier_hangup(struct hvc_struct *hp, int id)
 637{
 638	struct hvc_iucv_private *priv;
 639
 640	priv = hvc_iucv_get_private(id);
 641	if (!priv)
 642		return;
 643
 644	flush_sndbuf_sync(priv);
 645
 646	spin_lock_bh(&priv->lock);
 647	/* NOTE: If the hangup was scheduled by ourself (from the iucv
 648	 *	 path_servered callback [IUCV_SEVERED]), we have to clean up
 649	 *	 our structure and to set state to TTY_CLOSED.
 650	 *	 If the tty was hung up otherwise (e.g. vhangup()), then we
 651	 *	 ignore this hangup and keep an established IUCV path open...
 652	 *	 (...the reason is that we are not able to connect back to the
 653	 *	 client if we disconnect on hang up) */
 654	priv->tty_state = TTY_CLOSED;
 655
 656	if (priv->iucv_state == IUCV_SEVERED)
 657		hvc_iucv_cleanup(priv);
 658	spin_unlock_bh(&priv->lock);
 659}
 660
 661/**
 662 * hvc_iucv_dtr_rts() - HVC notifier for handling DTR/RTS
 663 * @hp:		Pointer the HVC device (struct hvc_struct)
 664 * @raise:	Non-zero to raise or zero to lower DTR/RTS lines
 665 *
 666 * This routine notifies the HVC back-end to raise or lower DTR/RTS
 667 * lines.  Raising DTR/RTS is ignored.  Lowering DTR/RTS indicates to
 668 * drop the IUCV connection (similar to hang up the modem).
 669 */
 670static void hvc_iucv_dtr_rts(struct hvc_struct *hp, int raise)
 671{
 672	struct hvc_iucv_private *priv;
 673	struct iucv_path        *path;
 674
 675	/* Raising the DTR/RTS is ignored as IUCV connections can be
 676	 * established at any times.
 677	 */
 678	if (raise)
 679		return;
 680
 681	priv = hvc_iucv_get_private(hp->vtermno);
 682	if (!priv)
 683		return;
 684
 685	/* Lowering the DTR/RTS lines disconnects an established IUCV
 686	 * connection.
 687	 */
 688	flush_sndbuf_sync(priv);
 689
 690	spin_lock_bh(&priv->lock);
 691	path = priv->path;		/* save reference to IUCV path */
 692	priv->path = NULL;
 693	priv->iucv_state = IUCV_DISCONN;
 694	spin_unlock_bh(&priv->lock);
 695
 696	/* Sever IUCV path outside of priv->lock due to lock ordering of:
 697	 * priv->lock <--> iucv_table_lock */
 698	if (path) {
 699		iucv_path_sever(path, NULL);
 700		iucv_path_free(path);
 701	}
 702}
 703
 704/**
 705 * hvc_iucv_notifier_del() - HVC notifier for closing a TTY for the last time.
 706 * @hp:		Pointer to the HVC device (struct hvc_struct)
 707 * @id:		Additional data (originally passed to hvc_alloc):
 708 *		the index of an struct hvc_iucv_private instance.
 709 *
 710 * This routine notifies the HVC back-end that the last tty device fd has been
 711 * closed.  The function cleans up tty resources.  The clean-up of the IUCV
 712 * connection is done in hvc_iucv_dtr_rts() and depends on the HUPCL termios
 713 * control setting.
 714 *
 715 * Locking:	struct hvc_iucv_private->lock
 716 */
 717static void hvc_iucv_notifier_del(struct hvc_struct *hp, int id)
 718{
 719	struct hvc_iucv_private *priv;
 720
 721	priv = hvc_iucv_get_private(id);
 722	if (!priv)
 723		return;
 724
 725	flush_sndbuf_sync(priv);
 726
 727	spin_lock_bh(&priv->lock);
 728	destroy_tty_buffer_list(&priv->tty_outqueue);
 729	destroy_tty_buffer_list(&priv->tty_inqueue);
 730	priv->tty_state = TTY_CLOSED;
 731	priv->sndbuf_len = 0;
 732	spin_unlock_bh(&priv->lock);
 733}
 734
 735/**
 736 * hvc_iucv_filter_connreq() - Filter connection request based on z/VM user ID
 737 * @ipvmid:	Originating z/VM user ID (right padded with blanks)
 738 *
 739 * Returns 0 if the z/VM user ID that is specified with @ipvmid is permitted to
 740 * connect, otherwise non-zero.
 741 */
 742static int hvc_iucv_filter_connreq(u8 ipvmid[8])
 743{
 744	const char *wildcard, *filter_entry;
 745	size_t i, len;
 746
 747	/* Note: default policy is ACCEPT if no filter is set */
 748	if (!hvc_iucv_filter_size)
 749		return 0;
 750
 751	for (i = 0; i < hvc_iucv_filter_size; i++) {
 752		filter_entry = hvc_iucv_filter + (8 * i);
 753
 754		/* If a filter entry contains the filter wildcard character,
 755		 * reduce the length to match the leading portion of the user
 756		 * ID only (wildcard match).  Characters following the wildcard
 757		 * are ignored.
 758		 */
 759		wildcard = strnchr(filter_entry, 8, FILTER_WILDCARD_CHAR);
 760		len = (wildcard) ? wildcard - filter_entry : 8;
 761		if (0 == memcmp(ipvmid, filter_entry, len))
 762			return 0;
 763	}
 764	return 1;
 765}
 766
 767/**
 768 * hvc_iucv_path_pending() - IUCV handler to process a connection request.
 769 * @path:	Pending path (struct iucv_path)
 770 * @ipvmid:	z/VM system identifier of originator
 771 * @ipuser:	User specified data for this path
 772 *		(AF_IUCV: port/service name and originator port)
 773 *
 774 * The function uses the @ipuser data to determine if the pending path belongs
 775 * to a terminal managed by this device driver.
 776 * If the path belongs to this driver, ensure that the terminal is not accessed
 777 * multiple times (only one connection to a terminal is allowed).
 778 * If the terminal is not yet connected, the pending path is accepted and is
 779 * associated to the appropriate struct hvc_iucv_private instance.
 780 *
 781 * Returns 0 if @path belongs to a terminal managed by the this device driver;
 782 * otherwise returns -ENODEV in order to dispatch this path to other handlers.
 783 *
 784 * Locking:	struct hvc_iucv_private->lock
 785 */
 786static	int hvc_iucv_path_pending(struct iucv_path *path, u8 *ipvmid,
 787				  u8 *ipuser)
 788{
 789	struct hvc_iucv_private *priv, *tmp;
 790	u8 wildcard[9] = "lnxhvc  ";
 791	int i, rc, find_unused;
 792	u8 nuser_data[16];
 793	u8 vm_user_id[9];
 794
 795	ASCEBC(wildcard, sizeof(wildcard));
 796	find_unused = !memcmp(wildcard, ipuser, 8);
 797
 798	/* First, check if the pending path request is managed by this
 799	 * IUCV handler:
 800	 * - find a disconnected device if ipuser contains the wildcard
 801	 * - find the device that matches the terminal ID in ipuser
 802	 */
 803	priv = NULL;
 804	for (i = 0; i < hvc_iucv_devices; i++) {
 805		tmp = hvc_iucv_table[i];
 806		if (!tmp)
 807			continue;
 808
 809		if (find_unused) {
 810			spin_lock(&tmp->lock);
 811			if (tmp->iucv_state == IUCV_DISCONN)
 812				priv = tmp;
 813			spin_unlock(&tmp->lock);
 814
 815		} else if (!memcmp(tmp->srv_name, ipuser, 8))
 816				priv = tmp;
 817		if (priv)
 818			break;
 819	}
 820	if (!priv)
 821		return -ENODEV;
 822
 823	/* Enforce that ipvmid is allowed to connect to us */
 824	read_lock(&hvc_iucv_filter_lock);
 825	rc = hvc_iucv_filter_connreq(ipvmid);
 826	read_unlock(&hvc_iucv_filter_lock);
 827	if (rc) {
 828		iucv_path_sever(path, ipuser);
 829		iucv_path_free(path);
 830		memcpy(vm_user_id, ipvmid, 8);
 831		vm_user_id[8] = 0;
 832		pr_info("A connection request from z/VM user ID %s "
 833			"was refused\n", vm_user_id);
 834		return 0;
 835	}
 836
 837	spin_lock(&priv->lock);
 838
 839	/* If the terminal is already connected or being severed, then sever
 840	 * this path to enforce that there is only ONE established communication
 841	 * path per terminal. */
 842	if (priv->iucv_state != IUCV_DISCONN) {
 843		iucv_path_sever(path, ipuser);
 844		iucv_path_free(path);
 845		goto out_path_handled;
 846	}
 847
 848	/* accept path */
 849	memcpy(nuser_data, ipuser + 8, 8);  /* remote service (for af_iucv) */
 850	memcpy(nuser_data + 8, ipuser, 8);  /* local service  (for af_iucv) */
 851	path->msglim = 0xffff;		    /* IUCV MSGLIMIT */
 852	path->flags &= ~IUCV_IPRMDATA;	    /* TODO: use IUCV_IPRMDATA */
 853	rc = iucv_path_accept(path, &hvc_iucv_handler, nuser_data, priv);
 854	if (rc) {
 855		iucv_path_sever(path, ipuser);
 856		iucv_path_free(path);
 857		goto out_path_handled;
 858	}
 859	priv->path = path;
 860	priv->iucv_state = IUCV_CONNECTED;
 861
 862	/* store path information */
 863	memcpy(priv->info_path, ipvmid, 8);
 864	memcpy(priv->info_path + 8, ipuser + 8, 8);
 865
 866	/* flush buffered output data... */
 867	schedule_delayed_work(&priv->sndbuf_work, 5);
 868
 869out_path_handled:
 870	spin_unlock(&priv->lock);
 871	return 0;
 872}
 873
 874/**
 875 * hvc_iucv_path_severed() - IUCV handler to process a path sever.
 876 * @path:	Pending path (struct iucv_path)
 877 * @ipuser:	User specified data for this path
 878 *		(AF_IUCV: port/service name and originator port)
 879 *
 880 * This function calls the hvc_iucv_hangup() function for the
 881 * respective IUCV HVC terminal.
 882 *
 883 * Locking:	struct hvc_iucv_private->lock
 884 */
 885static void hvc_iucv_path_severed(struct iucv_path *path, u8 *ipuser)
 886{
 887	struct hvc_iucv_private *priv = path->private;
 888
 889	hvc_iucv_hangup(priv);
 890}
 891
 892/**
 893 * hvc_iucv_msg_pending() - IUCV handler to process an incoming IUCV message.
 894 * @path:	Pending path (struct iucv_path)
 895 * @msg:	Pointer to the IUCV message
 896 *
 897 * The function puts an incoming message on the input queue for later
 898 * processing (by hvc_iucv_get_chars() / hvc_iucv_write()).
 899 * If the tty has not yet been opened, the message is rejected.
 900 *
 901 * Locking:	struct hvc_iucv_private->lock
 902 */
 903static void hvc_iucv_msg_pending(struct iucv_path *path,
 904				 struct iucv_message *msg)
 905{
 906	struct hvc_iucv_private *priv = path->private;
 907	struct iucv_tty_buffer *rb;
 908
 909	/* reject messages that exceed max size of iucv_tty_msg->datalen */
 910	if (msg->length > MSG_SIZE(MSG_MAX_DATALEN)) {
 911		iucv_message_reject(path, msg);
 912		return;
 913	}
 914
 915	spin_lock(&priv->lock);
 916
 917	/* reject messages if tty has not yet been opened */
 918	if (priv->tty_state == TTY_CLOSED) {
 919		iucv_message_reject(path, msg);
 920		goto unlock_return;
 921	}
 922
 923	/* allocate tty buffer to save iucv msg only */
 924	rb = alloc_tty_buffer(0, GFP_ATOMIC);
 925	if (!rb) {
 926		iucv_message_reject(path, msg);
 927		goto unlock_return;	/* -ENOMEM */
 928	}
 929	rb->msg = *msg;
 930
 931	list_add_tail(&rb->list, &priv->tty_inqueue);
 932
 933	hvc_kick();	/* wake up hvc thread */
 934
 935unlock_return:
 936	spin_unlock(&priv->lock);
 937}
 938
 939/**
 940 * hvc_iucv_msg_complete() - IUCV handler to process message completion
 941 * @path:	Pending path (struct iucv_path)
 942 * @msg:	Pointer to the IUCV message
 943 *
 944 * The function is called upon completion of message delivery to remove the
 945 * message from the outqueue. Additional delivery information can be found
 946 * msg->audit: rejected messages (0x040000 (IPADRJCT)), and
 947 *	       purged messages	 (0x010000 (IPADPGNR)).
 948 *
 949 * Locking:	struct hvc_iucv_private->lock
 950 */
 951static void hvc_iucv_msg_complete(struct iucv_path *path,
 952				  struct iucv_message *msg)
 953{
 954	struct hvc_iucv_private *priv = path->private;
 955	struct iucv_tty_buffer	*ent, *next;
 956	LIST_HEAD(list_remove);
 957
 958	spin_lock(&priv->lock);
 959	list_for_each_entry_safe(ent, next, &priv->tty_outqueue, list)
 960		if (ent->msg.id == msg->id) {
 961			list_move(&ent->list, &list_remove);
 962			break;
 963		}
 964	wake_up(&priv->sndbuf_waitq);
 965	spin_unlock(&priv->lock);
 966	destroy_tty_buffer_list(&list_remove);
 967}
 968
 969/**
 970 * hvc_iucv_pm_freeze() - Freeze PM callback
 971 * @dev:	IUVC HVC terminal device
 972 *
 973 * Sever an established IUCV communication path and
 974 * trigger a hang-up of the underlying HVC terminal.
 975 */
 976static int hvc_iucv_pm_freeze(struct device *dev)
 977{
 978	struct hvc_iucv_private *priv = dev_get_drvdata(dev);
 979
 980	local_bh_disable();
 981	hvc_iucv_hangup(priv);
 982	local_bh_enable();
 983
 984	return 0;
 985}
 986
 987/**
 988 * hvc_iucv_pm_restore_thaw() - Thaw and restore PM callback
 989 * @dev:	IUVC HVC terminal device
 990 *
 991 * Wake up the HVC thread to trigger hang-up and respective
 992 * HVC back-end notifier invocations.
 993 */
 994static int hvc_iucv_pm_restore_thaw(struct device *dev)
 995{
 996	hvc_kick();
 997	return 0;
 998}
 999
1000static ssize_t hvc_iucv_dev_termid_show(struct device *dev,
1001					struct device_attribute *attr,
1002					char *buf)
1003{
1004	struct hvc_iucv_private *priv = dev_get_drvdata(dev);
1005	size_t len;
1006
1007	len = sizeof(priv->srv_name);
1008	memcpy(buf, priv->srv_name, len);
1009	EBCASC(buf, len);
1010	buf[len++] = '\n';
1011	return len;
1012}
1013
1014static ssize_t hvc_iucv_dev_state_show(struct device *dev,
1015					struct device_attribute *attr,
1016					char *buf)
1017{
1018	struct hvc_iucv_private *priv = dev_get_drvdata(dev);
1019	return sprintf(buf, "%u:%u\n", priv->iucv_state, priv->tty_state);
1020}
1021
1022static ssize_t hvc_iucv_dev_peer_show(struct device *dev,
1023				      struct device_attribute *attr,
1024				      char *buf)
1025{
1026	struct hvc_iucv_private *priv = dev_get_drvdata(dev);
1027	char vmid[9], ipuser[9];
1028
1029	memset(vmid, 0, sizeof(vmid));
1030	memset(ipuser, 0, sizeof(ipuser));
1031
1032	spin_lock_bh(&priv->lock);
1033	if (priv->iucv_state == IUCV_CONNECTED) {
1034		memcpy(vmid, priv->info_path, 8);
1035		memcpy(ipuser, priv->info_path + 8, 8);
1036	}
1037	spin_unlock_bh(&priv->lock);
1038	EBCASC(ipuser, 8);
1039
1040	return sprintf(buf, "%s:%s\n", vmid, ipuser);
1041}
1042
1043
1044/* HVC operations */
1045static const struct hv_ops hvc_iucv_ops = {
1046	.get_chars = hvc_iucv_get_chars,
1047	.put_chars = hvc_iucv_put_chars,
1048	.notifier_add = hvc_iucv_notifier_add,
1049	.notifier_del = hvc_iucv_notifier_del,
1050	.notifier_hangup = hvc_iucv_notifier_hangup,
1051	.dtr_rts = hvc_iucv_dtr_rts,
1052};
1053
1054/* Suspend / resume device operations */
1055static const struct dev_pm_ops hvc_iucv_pm_ops = {
1056	.freeze	  = hvc_iucv_pm_freeze,
1057	.thaw	  = hvc_iucv_pm_restore_thaw,
1058	.restore  = hvc_iucv_pm_restore_thaw,
1059};
1060
1061/* IUCV HVC device driver */
1062static struct device_driver hvc_iucv_driver = {
1063	.name = KMSG_COMPONENT,
1064	.bus  = &iucv_bus,
1065	.pm   = &hvc_iucv_pm_ops,
1066};
1067
1068/* IUCV HVC device attributes */
1069static DEVICE_ATTR(termid, 0640, hvc_iucv_dev_termid_show, NULL);
1070static DEVICE_ATTR(state, 0640, hvc_iucv_dev_state_show, NULL);
1071static DEVICE_ATTR(peer, 0640, hvc_iucv_dev_peer_show, NULL);
1072static struct attribute *hvc_iucv_dev_attrs[] = {
1073	&dev_attr_termid.attr,
1074	&dev_attr_state.attr,
1075	&dev_attr_peer.attr,
1076	NULL,
1077};
1078static struct attribute_group hvc_iucv_dev_attr_group = {
1079	.attrs = hvc_iucv_dev_attrs,
1080};
1081static const struct attribute_group *hvc_iucv_dev_attr_groups[] = {
1082	&hvc_iucv_dev_attr_group,
1083	NULL,
1084};
1085
1086
1087/**
1088 * hvc_iucv_alloc() - Allocates a new struct hvc_iucv_private instance
1089 * @id:			hvc_iucv_table index
1090 * @is_console:		Flag if the instance is used as Linux console
1091 *
1092 * This function allocates a new hvc_iucv_private structure and stores
1093 * the instance in hvc_iucv_table at index @id.
1094 * Returns 0 on success; otherwise non-zero.
1095 */
1096static int __init hvc_iucv_alloc(int id, unsigned int is_console)
1097{
1098	struct hvc_iucv_private *priv;
1099	char name[9];
1100	int rc;
1101
1102	priv = kzalloc(sizeof(struct hvc_iucv_private), GFP_KERNEL);
1103	if (!priv)
1104		return -ENOMEM;
1105
1106	spin_lock_init(&priv->lock);
1107	INIT_LIST_HEAD(&priv->tty_outqueue);
1108	INIT_LIST_HEAD(&priv->tty_inqueue);
1109	INIT_DELAYED_WORK(&priv->sndbuf_work, hvc_iucv_sndbuf_work);
1110	init_waitqueue_head(&priv->sndbuf_waitq);
1111
1112	priv->sndbuf = (void *) get_zeroed_page(GFP_KERNEL);
1113	if (!priv->sndbuf) {
1114		kfree(priv);
1115		return -ENOMEM;
1116	}
1117
1118	/* set console flag */
1119	priv->is_console = is_console;
1120
1121	/* allocate hvc device */
1122	priv->hvc = hvc_alloc(HVC_IUCV_MAGIC + id, /*		  PAGE_SIZE */
1123			      HVC_IUCV_MAGIC + id, &hvc_iucv_ops, 256);
1124	if (IS_ERR(priv->hvc)) {
1125		rc = PTR_ERR(priv->hvc);
1126		goto out_error_hvc;
1127	}
1128
1129	/* notify HVC thread instead of using polling */
1130	priv->hvc->irq_requested = 1;
1131
1132	/* setup iucv related information */
1133	snprintf(name, 9, "lnxhvc%-2d", id);
1134	memcpy(priv->srv_name, name, 8);
1135	ASCEBC(priv->srv_name, 8);
1136
1137	/* create and setup device */
1138	priv->dev = kzalloc(sizeof(*priv->dev), GFP_KERNEL);
1139	if (!priv->dev) {
1140		rc = -ENOMEM;
1141		goto out_error_dev;
1142	}
1143	dev_set_name(priv->dev, "hvc_iucv%d", id);
1144	dev_set_drvdata(priv->dev, priv);
1145	priv->dev->bus = &iucv_bus;
1146	priv->dev->parent = iucv_root;
1147	priv->dev->driver = &hvc_iucv_driver;
1148	priv->dev->groups = hvc_iucv_dev_attr_groups;
1149	priv->dev->release = (void (*)(struct device *)) kfree;
1150	rc = device_register(priv->dev);
1151	if (rc) {
1152		put_device(priv->dev);
1153		goto out_error_dev;
1154	}
1155
1156	hvc_iucv_table[id] = priv;
1157	return 0;
1158
1159out_error_dev:
1160	hvc_remove(priv->hvc);
1161out_error_hvc:
1162	free_page((unsigned long) priv->sndbuf);
1163	kfree(priv);
1164
1165	return rc;
1166}
1167
1168/**
1169 * hvc_iucv_destroy() - Destroy and free hvc_iucv_private instances
1170 */
1171static void __init hvc_iucv_destroy(struct hvc_iucv_private *priv)
1172{
1173	hvc_remove(priv->hvc);
1174	device_unregister(priv->dev);
1175	free_page((unsigned long) priv->sndbuf);
1176	kfree(priv);
1177}
1178
1179/**
1180 * hvc_iucv_parse_filter() - Parse filter for a single z/VM user ID
1181 * @filter:	String containing a comma-separated list of z/VM user IDs
1182 * @dest:	Location where to store the parsed z/VM user ID
1183 */
1184static const char *hvc_iucv_parse_filter(const char *filter, char *dest)
1185{
1186	const char *nextdelim, *residual;
1187	size_t len;
1188
1189	nextdelim = strchr(filter, ',');
1190	if (nextdelim) {
1191		len = nextdelim - filter;
1192		residual = nextdelim + 1;
1193	} else {
1194		len = strlen(filter);
1195		residual = filter + len;
1196	}
1197
1198	if (len == 0)
1199		return ERR_PTR(-EINVAL);
1200
1201	/* check for '\n' (if called from sysfs) */
1202	if (filter[len - 1] == '\n')
1203		len--;
1204
1205	/* prohibit filter entries containing the wildcard character only */
1206	if (len == 1 && *filter == FILTER_WILDCARD_CHAR)
1207		return ERR_PTR(-EINVAL);
1208
1209	if (len > 8)
1210		return ERR_PTR(-EINVAL);
1211
1212	/* pad with blanks and save upper case version of user ID */
1213	memset(dest, ' ', 8);
1214	while (len--)
1215		dest[len] = toupper(filter[len]);
1216	return residual;
1217}
1218
1219/**
1220 * hvc_iucv_setup_filter() - Set up z/VM user ID filter
1221 * @filter:	String consisting of a comma-separated list of z/VM user IDs
1222 *
1223 * The function parses the @filter string and creates an array containing
1224 * the list of z/VM user ID filter entries.
1225 * Return code 0 means success, -EINVAL if the filter is syntactically
1226 * incorrect, -ENOMEM if there was not enough memory to allocate the
1227 * filter list array, or -ENOSPC if too many z/VM user IDs have been specified.
1228 */
1229static int hvc_iucv_setup_filter(const char *val)
1230{
1231	const char *residual;
1232	int err;
1233	size_t size, count;
1234	void *array, *old_filter;
1235
1236	count = strlen(val);
1237	if (count == 0 || (count == 1 && val[0] == '\n')) {
1238		size  = 0;
1239		array = NULL;
1240		goto out_replace_filter;	/* clear filter */
1241	}
1242
1243	/* count user IDs in order to allocate sufficient memory */
1244	size = 1;
1245	residual = val;
1246	while ((residual = strchr(residual, ',')) != NULL) {
1247		residual++;
1248		size++;
1249	}
1250
1251	/* check if the specified list exceeds the filter limit */
1252	if (size > MAX_VMID_FILTER)
1253		return -ENOSPC;
1254
1255	array = kcalloc(size, 8, GFP_KERNEL);
1256	if (!array)
1257		return -ENOMEM;
1258
1259	count = size;
1260	residual = val;
1261	while (*residual && count) {
1262		residual = hvc_iucv_parse_filter(residual,
1263						 array + ((size - count) * 8));
1264		if (IS_ERR(residual)) {
1265			err = PTR_ERR(residual);
1266			kfree(array);
1267			goto out_err;
1268		}
1269		count--;
1270	}
1271
1272out_replace_filter:
1273	write_lock_bh(&hvc_iucv_filter_lock);
1274	old_filter = hvc_iucv_filter;
1275	hvc_iucv_filter_size = size;
1276	hvc_iucv_filter = array;
1277	write_unlock_bh(&hvc_iucv_filter_lock);
1278	kfree(old_filter);
1279
1280	err = 0;
1281out_err:
1282	return err;
1283}
1284
1285/**
1286 * param_set_vmidfilter() - Set z/VM user ID filter parameter
1287 * @val:	String consisting of a comma-separated list of z/VM user IDs
1288 * @kp:		Kernel parameter pointing to hvc_iucv_filter array
1289 *
1290 * The function sets up the z/VM user ID filter specified as comma-separated
1291 * list of user IDs in @val.
1292 * Note: If it is called early in the boot process, @val is stored and
1293 *	 parsed later in hvc_iucv_init().
1294 */
1295static int param_set_vmidfilter(const char *val, const struct kernel_param *kp)
1296{
1297	int rc;
1298
1299	if (!MACHINE_IS_VM || !hvc_iucv_devices)
1300		return -ENODEV;
1301
1302	if (!val)
1303		return -EINVAL;
1304
1305	rc = 0;
1306	if (slab_is_available())
1307		rc = hvc_iucv_setup_filter(val);
1308	else
1309		hvc_iucv_filter_string = val;	/* defer... */
1310	return rc;
1311}
1312
1313/**
1314 * param_get_vmidfilter() - Get z/VM user ID filter
1315 * @buffer:	Buffer to store z/VM user ID filter,
1316 *		(buffer size assumption PAGE_SIZE)
1317 * @kp:		Kernel parameter pointing to the hvc_iucv_filter array
1318 *
1319 * The function stores the filter as a comma-separated list of z/VM user IDs
1320 * in @buffer. Typically, sysfs routines call this function for attr show.
1321 */
1322static int param_get_vmidfilter(char *buffer, const struct kernel_param *kp)
1323{
1324	int rc;
1325	size_t index, len;
1326	void *start, *end;
1327
1328	if (!MACHINE_IS_VM || !hvc_iucv_devices)
1329		return -ENODEV;
1330
1331	rc = 0;
1332	read_lock_bh(&hvc_iucv_filter_lock);
1333	for (index = 0; index < hvc_iucv_filter_size; index++) {
1334		start = hvc_iucv_filter + (8 * index);
1335		end   = memchr(start, ' ', 8);
1336		len   = (end) ? end - start : 8;
1337		memcpy(buffer + rc, start, len);
1338		rc += len;
1339		buffer[rc++] = ',';
1340	}
1341	read_unlock_bh(&hvc_iucv_filter_lock);
1342	if (rc)
1343		buffer[--rc] = '\0';	/* replace last comma and update rc */
1344	return rc;
1345}
1346
1347#define param_check_vmidfilter(name, p) __param_check(name, p, void)
1348
1349static const struct kernel_param_ops param_ops_vmidfilter = {
1350	.set = param_set_vmidfilter,
1351	.get = param_get_vmidfilter,
1352};
1353
1354/**
1355 * hvc_iucv_init() - z/VM IUCV HVC device driver initialization
1356 */
1357static int __init hvc_iucv_init(void)
1358{
1359	int rc;
1360	unsigned int i;
1361
1362	if (!hvc_iucv_devices)
1363		return -ENODEV;
1364
1365	if (!MACHINE_IS_VM) {
1366		pr_notice("The z/VM IUCV HVC device driver cannot "
1367			   "be used without z/VM\n");
1368		rc = -ENODEV;
1369		goto out_error;
1370	}
1371
1372	if (hvc_iucv_devices > MAX_HVC_IUCV_LINES) {
1373		pr_err("%lu is not a valid value for the hvc_iucv= "
1374			"kernel parameter\n", hvc_iucv_devices);
1375		rc = -EINVAL;
1376		goto out_error;
1377	}
1378
1379	/* register IUCV HVC device driver */
1380	rc = driver_register(&hvc_iucv_driver);
1381	if (rc)
1382		goto out_error;
1383
1384	/* parse hvc_iucv_allow string and create z/VM user ID filter list */
1385	if (hvc_iucv_filter_string) {
1386		rc = hvc_iucv_setup_filter(hvc_iucv_filter_string);
1387		switch (rc) {
1388		case 0:
1389			break;
1390		case -ENOMEM:
1391			pr_err("Allocating memory failed with "
1392				"reason code=%d\n", 3);
1393			goto out_error;
1394		case -EINVAL:
1395			pr_err("hvc_iucv_allow= does not specify a valid "
1396				"z/VM user ID list\n");
1397			goto out_error;
1398		case -ENOSPC:
1399			pr_err("hvc_iucv_allow= specifies too many "
1400				"z/VM user IDs\n");
1401			goto out_error;
1402		default:
1403			goto out_error;
1404		}
1405	}
1406
1407	hvc_iucv_buffer_cache = kmem_cache_create(KMSG_COMPONENT,
1408					   sizeof(struct iucv_tty_buffer),
1409					   0, 0, NULL);
1410	if (!hvc_iucv_buffer_cache) {
1411		pr_err("Allocating memory failed with reason code=%d\n", 1);
1412		rc = -ENOMEM;
1413		goto out_error;
1414	}
1415
1416	hvc_iucv_mempool = mempool_create_slab_pool(MEMPOOL_MIN_NR,
1417						    hvc_iucv_buffer_cache);
1418	if (!hvc_iucv_mempool) {
1419		pr_err("Allocating memory failed with reason code=%d\n", 2);
1420		kmem_cache_destroy(hvc_iucv_buffer_cache);
1421		rc = -ENOMEM;
1422		goto out_error;
1423	}
1424
1425	/* register the first terminal device as console
1426	 * (must be done before allocating hvc terminal devices) */
1427	rc = hvc_instantiate(HVC_IUCV_MAGIC, IUCV_HVC_CON_IDX, &hvc_iucv_ops);
1428	if (rc) {
1429		pr_err("Registering HVC terminal device as "
1430		       "Linux console failed\n");
1431		goto out_error_memory;
1432	}
1433
1434	/* allocate hvc_iucv_private structs */
1435	for (i = 0; i < hvc_iucv_devices; i++) {
1436		rc = hvc_iucv_alloc(i, (i == IUCV_HVC_CON_IDX) ? 1 : 0);
1437		if (rc) {
1438			pr_err("Creating a new HVC terminal device "
1439				"failed with error code=%d\n", rc);
1440			goto out_error_hvc;
1441		}
1442	}
1443
1444	/* register IUCV callback handler */
1445	rc = iucv_register(&hvc_iucv_handler, 0);
1446	if (rc) {
1447		pr_err("Registering IUCV handlers failed with error code=%d\n",
1448			rc);
1449		goto out_error_hvc;
1450	}
1451
1452	return 0;
1453
1454out_error_hvc:
1455	for (i = 0; i < hvc_iucv_devices; i++)
1456		if (hvc_iucv_table[i])
1457			hvc_iucv_destroy(hvc_iucv_table[i]);
1458out_error_memory:
1459	mempool_destroy(hvc_iucv_mempool);
1460	kmem_cache_destroy(hvc_iucv_buffer_cache);
1461out_error:
1462	kfree(hvc_iucv_filter);
1463	hvc_iucv_devices = 0; /* ensure that we do not provide any device */
1464	return rc;
1465}
1466
1467/**
1468 * hvc_iucv_config() - Parsing of hvc_iucv=  kernel command line parameter
1469 * @val:	Parameter value (numeric)
1470 */
1471static	int __init hvc_iucv_config(char *val)
1472{
1473	 return kstrtoul(val, 10, &hvc_iucv_devices);
1474}
1475
1476
1477device_initcall(hvc_iucv_init);
1478__setup("hvc_iucv=", hvc_iucv_config);
1479core_param(hvc_iucv_allow, hvc_iucv_filter, vmidfilter, 0640);