hvc_iucv.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * z/VM IUCV hypervisor console (HVC) device driver
   4 *
   5 * This HVC device driver provides terminal access using
   6 * z/VM IUCV communication paths.
   7 *
   8 * Copyright IBM Corp. 2008, 2013
   9 *
  10 * Author(s):	Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
  11 */
  12#define KMSG_COMPONENT		"hvc_iucv"
  13#define pr_fmt(fmt)		KMSG_COMPONENT ": " fmt
  14
  15#include <linux/types.h>
  16#include <linux/slab.h>
  17#include <asm/ebcdic.h>
  18#include <linux/ctype.h>
  19#include <linux/delay.h>
  20#include <linux/device.h>
  21#include <linux/init.h>
  22#include <linux/mempool.h>
  23#include <linux/moduleparam.h>
  24#include <linux/tty.h>
  25#include <linux/wait.h>
  26#include <net/iucv/iucv.h>
  27#include <asm/machine.h>
  28
  29#include "hvc_console.h"
  30
  31
  32/* General device driver settings */
  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_devices)
 135		return NULL;
 136	return hvc_iucv_table[num];
 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 ssize_t hvc_iucv_write(struct hvc_iucv_private *priv,
 220			      u8 *buf, size_t count, int *has_more_data)
 221{
 222	struct iucv_tty_buffer *rb;
 223	ssize_t 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 ssize_t hvc_iucv_get_chars(uint32_t vtermno, u8 *buf, size_t count)
 317{
 318	struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 319	ssize_t 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 ssize_t hvc_iucv_queue(struct hvc_iucv_private *priv, const u8 *buf,
 357			      size_t 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
 442	spin_lock_bh(&priv->lock);
 443	hvc_iucv_send(priv);
 444	spin_unlock_bh(&priv->lock);
 445}
 446
 447/**
 448 * hvc_iucv_put_chars() - HVC put_chars operation.
 449 * @vtermno:	HVC virtual terminal number.
 450 * @buf:	Pointer to an buffer to read data from
 451 * @count:	Size of buffer available for reading
 452 *
 453 * The HVC thread calls this method to write characters to the back-end.
 454 * The function calls hvc_iucv_queue() to queue terminal data for sending.
 455 *
 456 * Locking:	The method gets called under an irqsave() spinlock; and
 457 *		locks struct hvc_iucv_private->lock.
 458 */
 459static ssize_t hvc_iucv_put_chars(uint32_t vtermno, const u8 *buf, size_t count)
 460{
 461	struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 462	int queued;
 463
 464	if (!count)
 465		return 0;
 466
 467	if (!priv)
 468		return -ENODEV;
 469
 470	spin_lock(&priv->lock);
 471	queued = hvc_iucv_queue(priv, buf, count);
 472	spin_unlock(&priv->lock);
 473
 474	return queued;
 475}
 476
 477/**
 478 * hvc_iucv_notifier_add() - HVC notifier for opening a TTY for the first time.
 479 * @hp:	Pointer to the HVC device (struct hvc_struct)
 480 * @id:	Additional data (originally passed to hvc_alloc): the index of an struct
 481 *	hvc_iucv_private instance.
 482 *
 483 * The function sets the tty state to TTY_OPENED for the struct hvc_iucv_private
 484 * instance that is derived from @id. Always returns 0.
 485 *
 486 * Locking:	struct hvc_iucv_private->lock, spin_lock_bh
 487 */
 488static int hvc_iucv_notifier_add(struct hvc_struct *hp, int id)
 489{
 490	struct hvc_iucv_private *priv;
 491
 492	priv = hvc_iucv_get_private(id);
 493	if (!priv)
 494		return 0;
 495
 496	spin_lock_bh(&priv->lock);
 497	priv->tty_state = TTY_OPENED;
 498	spin_unlock_bh(&priv->lock);
 499
 500	return 0;
 501}
 502
 503/**
 504 * hvc_iucv_cleanup() - Clean up and reset a z/VM IUCV HVC instance.
 505 * @priv:	Pointer to the struct hvc_iucv_private instance.
 506 */
 507static void hvc_iucv_cleanup(struct hvc_iucv_private *priv)
 508{
 509	destroy_tty_buffer_list(&priv->tty_outqueue);
 510	destroy_tty_buffer_list(&priv->tty_inqueue);
 511
 512	priv->tty_state = TTY_CLOSED;
 513	priv->iucv_state = IUCV_DISCONN;
 514
 515	priv->sndbuf_len = 0;
 516}
 517
 518/**
 519 * tty_outqueue_empty() - Test if the tty outq is empty
 520 * @priv:	Pointer to struct hvc_iucv_private instance.
 521 */
 522static inline int tty_outqueue_empty(struct hvc_iucv_private *priv)
 523{
 524	int rc;
 525
 526	spin_lock_bh(&priv->lock);
 527	rc = list_empty(&priv->tty_outqueue);
 528	spin_unlock_bh(&priv->lock);
 529
 530	return rc;
 531}
 532
 533/**
 534 * flush_sndbuf_sync() - Flush send buffer and wait for completion
 535 * @priv:	Pointer to struct hvc_iucv_private instance.
 536 *
 537 * The routine cancels a pending sndbuf work, calls hvc_iucv_send()
 538 * to flush any buffered terminal output data and waits for completion.
 539 */
 540static void flush_sndbuf_sync(struct hvc_iucv_private *priv)
 541{
 542	int sync_wait;
 543
 544	cancel_delayed_work_sync(&priv->sndbuf_work);
 545
 546	spin_lock_bh(&priv->lock);
 547	hvc_iucv_send(priv);		/* force sending buffered data */
 548	sync_wait = !list_empty(&priv->tty_outqueue); /* anything queued ? */
 549	spin_unlock_bh(&priv->lock);
 550
 551	if (sync_wait)
 552		wait_event_timeout(priv->sndbuf_waitq,
 553				   tty_outqueue_empty(priv), HZ/10);
 554}
 555
 556/**
 557 * hvc_iucv_hangup() - Sever IUCV path and schedule hvc tty hang up
 558 * @priv:	Pointer to hvc_iucv_private structure
 559 *
 560 * This routine severs an existing IUCV communication path and hangs
 561 * up the underlying HVC terminal device.
 562 * The hang-up occurs only if an IUCV communication path is established;
 563 * otherwise there is no need to hang up the terminal device.
 564 *
 565 * The IUCV HVC hang-up is separated into two steps:
 566 * 1. After the IUCV path has been severed, the iucv_state is set to
 567 *    IUCV_SEVERED.
 568 * 2. Later, when the HVC thread calls hvc_iucv_get_chars(), the
 569 *    IUCV_SEVERED state causes the tty hang-up in the HVC layer.
 570 *
 571 * If the tty has not yet been opened, clean up the hvc_iucv_private
 572 * structure to allow re-connects.
 573 * If the tty has been opened, let get_chars() return -EPIPE to signal
 574 * the HVC layer to hang up the tty and, if so, wake up the HVC thread
 575 * to call get_chars()...
 576 *
 577 * Special notes on hanging up a HVC terminal instantiated as console:
 578 * Hang-up:	1. do_tty_hangup() replaces file ops (= hung_up_tty_fops)
 579 *		2. do_tty_hangup() calls tty->ops->close() for console_filp
 580 *			=> no hangup notifier is called by HVC (default)
 581 *		2. hvc_close() returns because of tty_hung_up_p(filp)
 582 *			=> no delete notifier is called!
 583 * Finally, the back-end is not being notified, thus, the tty session is
 584 * kept active (TTY_OPEN) to be ready for re-connects.
 585 *
 586 * Locking:	spin_lock(&priv->lock) w/o disabling bh
 587 */
 588static void hvc_iucv_hangup(struct hvc_iucv_private *priv)
 589{
 590	struct iucv_path *path;
 591
 592	path = NULL;
 593	spin_lock(&priv->lock);
 594	if (priv->iucv_state == IUCV_CONNECTED) {
 595		path = priv->path;
 596		priv->path = NULL;
 597		priv->iucv_state = IUCV_SEVERED;
 598		if (priv->tty_state == TTY_CLOSED)
 599			hvc_iucv_cleanup(priv);
 600		else
 601			/* console is special (see above) */
 602			if (priv->is_console) {
 603				hvc_iucv_cleanup(priv);
 604				priv->tty_state = TTY_OPENED;
 605			} else
 606				hvc_kick();
 607	}
 608	spin_unlock(&priv->lock);
 609
 610	/* finally sever path (outside of priv->lock due to lock ordering) */
 611	if (path) {
 612		iucv_path_sever(path, NULL);
 613		iucv_path_free(path);
 614	}
 615}
 616
 617/**
 618 * hvc_iucv_notifier_hangup() - HVC notifier for TTY hangups.
 619 * @hp:		Pointer to the HVC device (struct hvc_struct)
 620 * @id:		Additional data (originally passed to hvc_alloc):
 621 *		the index of an struct hvc_iucv_private instance.
 622 *
 623 * This routine notifies the HVC back-end that a tty hangup (carrier loss,
 624 * virtual or otherwise) has occurred.
 625 * The z/VM IUCV HVC device driver ignores virtual hangups (vhangup())
 626 * to keep an existing IUCV communication path established.
 627 * (Background: vhangup() is called from user space (by getty or login) to
 628 *		disable writing to the tty by other applications).
 629 * If the tty has been opened and an established IUCV path has been severed
 630 * (we caused the tty hangup), the function calls hvc_iucv_cleanup().
 631 *
 632 * Locking:	struct hvc_iucv_private->lock
 633 */
 634static void hvc_iucv_notifier_hangup(struct hvc_struct *hp, int id)
 635{
 636	struct hvc_iucv_private *priv;
 637
 638	priv = hvc_iucv_get_private(id);
 639	if (!priv)
 640		return;
 641
 642	flush_sndbuf_sync(priv);
 643
 644	spin_lock_bh(&priv->lock);
 645	/* NOTE: If the hangup was scheduled by ourself (from the iucv
 646	 *	 path_servered callback [IUCV_SEVERED]), we have to clean up
 647	 *	 our structure and to set state to TTY_CLOSED.
 648	 *	 If the tty was hung up otherwise (e.g. vhangup()), then we
 649	 *	 ignore this hangup and keep an established IUCV path open...
 650	 *	 (...the reason is that we are not able to connect back to the
 651	 *	 client if we disconnect on hang up) */
 652	priv->tty_state = TTY_CLOSED;
 653
 654	if (priv->iucv_state == IUCV_SEVERED)
 655		hvc_iucv_cleanup(priv);
 656	spin_unlock_bh(&priv->lock);
 657}
 658
 659/**
 660 * hvc_iucv_dtr_rts() - HVC notifier for handling DTR/RTS
 661 * @hp:		Pointer the HVC device (struct hvc_struct)
 662 * @active:	True to raise or false to lower DTR/RTS lines
 663 *
 664 * This routine notifies the HVC back-end to raise or lower DTR/RTS
 665 * lines.  Raising DTR/RTS is ignored.  Lowering DTR/RTS indicates to
 666 * drop the IUCV connection (similar to hang up the modem).
 667 */
 668static void hvc_iucv_dtr_rts(struct hvc_struct *hp, bool active)
 669{
 670	struct hvc_iucv_private *priv;
 671	struct iucv_path        *path;
 672
 673	/* Raising the DTR/RTS is ignored as IUCV connections can be
 674	 * established at any times.
 675	 */
 676	if (active)
 677		return;
 678
 679	priv = hvc_iucv_get_private(hp->vtermno);
 680	if (!priv)
 681		return;
 682
 683	/* Lowering the DTR/RTS lines disconnects an established IUCV
 684	 * connection.
 685	 */
 686	flush_sndbuf_sync(priv);
 687
 688	spin_lock_bh(&priv->lock);
 689	path = priv->path;		/* save reference to IUCV path */
 690	priv->path = NULL;
 691	priv->iucv_state = IUCV_DISCONN;
 692	spin_unlock_bh(&priv->lock);
 693
 694	/* Sever IUCV path outside of priv->lock due to lock ordering of:
 695	 * priv->lock <--> iucv_table_lock */
 696	if (path) {
 697		iucv_path_sever(path, NULL);
 698		iucv_path_free(path);
 699	}
 700}
 701
 702/**
 703 * hvc_iucv_notifier_del() - HVC notifier for closing a TTY for the last time.
 704 * @hp:		Pointer to the HVC device (struct hvc_struct)
 705 * @id:		Additional data (originally passed to hvc_alloc):
 706 *		the index of an struct hvc_iucv_private instance.
 707 *
 708 * This routine notifies the HVC back-end that the last tty device fd has been
 709 * closed.  The function cleans up tty resources.  The clean-up of the IUCV
 710 * connection is done in hvc_iucv_dtr_rts() and depends on the HUPCL termios
 711 * control setting.
 712 *
 713 * Locking:	struct hvc_iucv_private->lock
 714 */
 715static void hvc_iucv_notifier_del(struct hvc_struct *hp, int id)
 716{
 717	struct hvc_iucv_private *priv;
 718
 719	priv = hvc_iucv_get_private(id);
 720	if (!priv)
 721		return;
 722
 723	flush_sndbuf_sync(priv);
 724
 725	spin_lock_bh(&priv->lock);
 726	destroy_tty_buffer_list(&priv->tty_outqueue);
 727	destroy_tty_buffer_list(&priv->tty_inqueue);
 728	priv->tty_state = TTY_CLOSED;
 729	priv->sndbuf_len = 0;
 730	spin_unlock_bh(&priv->lock);
 731}
 732
 733/**
 734 * hvc_iucv_filter_connreq() - Filter connection request based on z/VM user ID
 735 * @ipvmid:	Originating z/VM user ID (right padded with blanks)
 736 *
 737 * Returns 0 if the z/VM user ID that is specified with @ipvmid is permitted to
 738 * connect, otherwise non-zero.
 739 */
 740static int hvc_iucv_filter_connreq(u8 ipvmid[8])
 741{
 742	const char *wildcard, *filter_entry;
 743	size_t i, len;
 744
 745	/* Note: default policy is ACCEPT if no filter is set */
 746	if (!hvc_iucv_filter_size)
 747		return 0;
 748
 749	for (i = 0; i < hvc_iucv_filter_size; i++) {
 750		filter_entry = hvc_iucv_filter + (8 * i);
 751
 752		/* If a filter entry contains the filter wildcard character,
 753		 * reduce the length to match the leading portion of the user
 754		 * ID only (wildcard match).  Characters following the wildcard
 755		 * are ignored.
 756		 */
 757		wildcard = strnchr(filter_entry, 8, FILTER_WILDCARD_CHAR);
 758		len = (wildcard) ? wildcard - filter_entry : 8;
 759		if (0 == memcmp(ipvmid, filter_entry, len))
 760			return 0;
 761	}
 762	return 1;
 763}
 764
 765/**
 766 * hvc_iucv_path_pending() - IUCV handler to process a connection request.
 767 * @path:	Pending path (struct iucv_path)
 768 * @ipvmid:	z/VM system identifier of originator
 769 * @ipuser:	User specified data for this path
 770 *		(AF_IUCV: port/service name and originator port)
 771 *
 772 * The function uses the @ipuser data to determine if the pending path belongs
 773 * to a terminal managed by this device driver.
 774 * If the path belongs to this driver, ensure that the terminal is not accessed
 775 * multiple times (only one connection to a terminal is allowed).
 776 * If the terminal is not yet connected, the pending path is accepted and is
 777 * associated to the appropriate struct hvc_iucv_private instance.
 778 *
 779 * Returns 0 if @path belongs to a terminal managed by the this device driver;
 780 * otherwise returns -ENODEV in order to dispatch this path to other handlers.
 781 *
 782 * Locking:	struct hvc_iucv_private->lock
 783 */
 784static	int hvc_iucv_path_pending(struct iucv_path *path, u8 *ipvmid,
 785				  u8 *ipuser)
 786{
 787	struct hvc_iucv_private *priv, *tmp;
 788	u8 wildcard[9] = "lnxhvc  ";
 789	int i, rc, find_unused;
 790	u8 nuser_data[16];
 791	u8 vm_user_id[9];
 792
 793	ASCEBC(wildcard, sizeof(wildcard));
 794	find_unused = !memcmp(wildcard, ipuser, 8);
 795
 796	/* First, check if the pending path request is managed by this
 797	 * IUCV handler:
 798	 * - find a disconnected device if ipuser contains the wildcard
 799	 * - find the device that matches the terminal ID in ipuser
 800	 */
 801	priv = NULL;
 802	for (i = 0; i < hvc_iucv_devices; i++) {
 803		tmp = hvc_iucv_table[i];
 804		if (!tmp)
 805			continue;
 806
 807		if (find_unused) {
 808			spin_lock(&tmp->lock);
 809			if (tmp->iucv_state == IUCV_DISCONN)
 810				priv = tmp;
 811			spin_unlock(&tmp->lock);
 812
 813		} else if (!memcmp(tmp->srv_name, ipuser, 8))
 814				priv = tmp;
 815		if (priv)
 816			break;
 817	}
 818	if (!priv)
 819		return -ENODEV;
 820
 821	/* Enforce that ipvmid is allowed to connect to us */
 822	read_lock(&hvc_iucv_filter_lock);
 823	rc = hvc_iucv_filter_connreq(ipvmid);
 824	read_unlock(&hvc_iucv_filter_lock);
 825	if (rc) {
 826		iucv_path_sever(path, ipuser);
 827		iucv_path_free(path);
 828		memcpy(vm_user_id, ipvmid, 8);
 829		vm_user_id[8] = 0;
 830		pr_info("A connection request from z/VM user ID %s "
 831			"was refused\n", vm_user_id);
 832		return 0;
 833	}
 834
 835	spin_lock(&priv->lock);
 836
 837	/* If the terminal is already connected or being severed, then sever
 838	 * this path to enforce that there is only ONE established communication
 839	 * path per terminal. */
 840	if (priv->iucv_state != IUCV_DISCONN) {
 841		iucv_path_sever(path, ipuser);
 842		iucv_path_free(path);
 843		goto out_path_handled;
 844	}
 845
 846	/* accept path */
 847	memcpy(nuser_data, ipuser + 8, 8);  /* remote service (for af_iucv) */
 848	memcpy(nuser_data + 8, ipuser, 8);  /* local service  (for af_iucv) */
 849	path->msglim = 0xffff;		    /* IUCV MSGLIMIT */
 850	path->flags &= ~IUCV_IPRMDATA;	    /* TODO: use IUCV_IPRMDATA */
 851	rc = iucv_path_accept(path, &hvc_iucv_handler, nuser_data, priv);
 852	if (rc) {
 853		iucv_path_sever(path, ipuser);
 854		iucv_path_free(path);
 855		goto out_path_handled;
 856	}
 857	priv->path = path;
 858	priv->iucv_state = IUCV_CONNECTED;
 859
 860	/* store path information */
 861	memcpy(priv->info_path, ipvmid, 8);
 862	memcpy(priv->info_path + 8, ipuser + 8, 8);
 863
 864	/* flush buffered output data... */
 865	schedule_delayed_work(&priv->sndbuf_work, 5);
 866
 867out_path_handled:
 868	spin_unlock(&priv->lock);
 869	return 0;
 870}
 871
 872/**
 873 * hvc_iucv_path_severed() - IUCV handler to process a path sever.
 874 * @path:	Pending path (struct iucv_path)
 875 * @ipuser:	User specified data for this path
 876 *		(AF_IUCV: port/service name and originator port)
 877 *
 878 * This function calls the hvc_iucv_hangup() function for the
 879 * respective IUCV HVC terminal.
 880 *
 881 * Locking:	struct hvc_iucv_private->lock
 882 */
 883static void hvc_iucv_path_severed(struct iucv_path *path, u8 *ipuser)
 884{
 885	struct hvc_iucv_private *priv = path->private;
 886
 887	hvc_iucv_hangup(priv);
 888}
 889
 890/**
 891 * hvc_iucv_msg_pending() - IUCV handler to process an incoming IUCV message.
 892 * @path:	Pending path (struct iucv_path)
 893 * @msg:	Pointer to the IUCV message
 894 *
 895 * The function puts an incoming message on the input queue for later
 896 * processing (by hvc_iucv_get_chars() / hvc_iucv_write()).
 897 * If the tty has not yet been opened, the message is rejected.
 898 *
 899 * Locking:	struct hvc_iucv_private->lock
 900 */
 901static void hvc_iucv_msg_pending(struct iucv_path *path,
 902				 struct iucv_message *msg)
 903{
 904	struct hvc_iucv_private *priv = path->private;
 905	struct iucv_tty_buffer *rb;
 906
 907	/* reject messages that exceed max size of iucv_tty_msg->datalen */
 908	if (msg->length > MSG_SIZE(MSG_MAX_DATALEN)) {
 909		iucv_message_reject(path, msg);
 910		return;
 911	}
 912
 913	spin_lock(&priv->lock);
 914
 915	/* reject messages if tty has not yet been opened */
 916	if (priv->tty_state == TTY_CLOSED) {
 917		iucv_message_reject(path, msg);
 918		goto unlock_return;
 919	}
 920
 921	/* allocate tty buffer to save iucv msg only */
 922	rb = alloc_tty_buffer(0, GFP_ATOMIC);
 923	if (!rb) {
 924		iucv_message_reject(path, msg);
 925		goto unlock_return;	/* -ENOMEM */
 926	}
 927	rb->msg = *msg;
 928
 929	list_add_tail(&rb->list, &priv->tty_inqueue);
 930
 931	hvc_kick();	/* wake up hvc thread */
 932
 933unlock_return:
 934	spin_unlock(&priv->lock);
 935}
 936
 937/**
 938 * hvc_iucv_msg_complete() - IUCV handler to process message completion
 939 * @path:	Pending path (struct iucv_path)
 940 * @msg:	Pointer to the IUCV message
 941 *
 942 * The function is called upon completion of message delivery to remove the
 943 * message from the outqueue. Additional delivery information can be found
 944 * msg->audit: rejected messages (0x040000 (IPADRJCT)), and
 945 *	       purged messages	 (0x010000 (IPADPGNR)).
 946 *
 947 * Locking:	struct hvc_iucv_private->lock
 948 */
 949static void hvc_iucv_msg_complete(struct iucv_path *path,
 950				  struct iucv_message *msg)
 951{
 952	struct hvc_iucv_private *priv = path->private;
 953	struct iucv_tty_buffer	*ent, *next;
 954	LIST_HEAD(list_remove);
 955
 956	spin_lock(&priv->lock);
 957	list_for_each_entry_safe(ent, next, &priv->tty_outqueue, list)
 958		if (ent->msg.id == msg->id) {
 959			list_move(&ent->list, &list_remove);
 960			break;
 961		}
 962	wake_up(&priv->sndbuf_waitq);
 963	spin_unlock(&priv->lock);
 964	destroy_tty_buffer_list(&list_remove);
 965}
 966
 967static ssize_t hvc_iucv_dev_termid_show(struct device *dev,
 968					struct device_attribute *attr,
 969					char *buf)
 970{
 971	struct hvc_iucv_private *priv = dev_get_drvdata(dev);
 972	size_t len;
 973
 974	len = sizeof(priv->srv_name);
 975	memcpy(buf, priv->srv_name, len);
 976	EBCASC(buf, len);
 977	buf[len++] = '\n';
 978	return len;
 979}
 980
 981static ssize_t hvc_iucv_dev_state_show(struct device *dev,
 982					struct device_attribute *attr,
 983					char *buf)
 984{
 985	struct hvc_iucv_private *priv = dev_get_drvdata(dev);
 986	return sprintf(buf, "%u:%u\n", priv->iucv_state, priv->tty_state);
 987}
 988
 989static ssize_t hvc_iucv_dev_peer_show(struct device *dev,
 990				      struct device_attribute *attr,
 991				      char *buf)
 992{
 993	struct hvc_iucv_private *priv = dev_get_drvdata(dev);
 994	char vmid[9], ipuser[9];
 995
 996	memset(vmid, 0, sizeof(vmid));
 997	memset(ipuser, 0, sizeof(ipuser));
 998
 999	spin_lock_bh(&priv->lock);
1000	if (priv->iucv_state == IUCV_CONNECTED) {
1001		memcpy(vmid, priv->info_path, 8);
1002		memcpy(ipuser, priv->info_path + 8, 8);
1003	}
1004	spin_unlock_bh(&priv->lock);
1005	EBCASC(ipuser, 8);
1006
1007	return sprintf(buf, "%s:%s\n", vmid, ipuser);
1008}
1009
1010
1011/* HVC operations */
1012static const struct hv_ops hvc_iucv_ops = {
1013	.get_chars = hvc_iucv_get_chars,
1014	.put_chars = hvc_iucv_put_chars,
1015	.notifier_add = hvc_iucv_notifier_add,
1016	.notifier_del = hvc_iucv_notifier_del,
1017	.notifier_hangup = hvc_iucv_notifier_hangup,
1018	.dtr_rts = hvc_iucv_dtr_rts,
1019};
1020
1021/* IUCV HVC device attributes */
1022static DEVICE_ATTR(termid, 0640, hvc_iucv_dev_termid_show, NULL);
1023static DEVICE_ATTR(state, 0640, hvc_iucv_dev_state_show, NULL);
1024static DEVICE_ATTR(peer, 0640, hvc_iucv_dev_peer_show, NULL);
1025static struct attribute *hvc_iucv_dev_attrs[] = {
1026	&dev_attr_termid.attr,
1027	&dev_attr_state.attr,
1028	&dev_attr_peer.attr,
1029	NULL,
1030};
1031static struct attribute_group hvc_iucv_dev_attr_group = {
1032	.attrs = hvc_iucv_dev_attrs,
1033};
1034static const struct attribute_group *hvc_iucv_dev_attr_groups[] = {
1035	&hvc_iucv_dev_attr_group,
1036	NULL,
1037};
1038
1039/**
1040 * hvc_iucv_alloc() - Allocates a new struct hvc_iucv_private instance
1041 * @id:			hvc_iucv_table index
1042 * @is_console:		Flag if the instance is used as Linux console
1043 *
1044 * This function allocates a new hvc_iucv_private structure and stores
1045 * the instance in hvc_iucv_table at index @id.
1046 * Returns 0 on success; otherwise non-zero.
1047 */
1048static int __init hvc_iucv_alloc(int id, unsigned int is_console)
1049{
1050	struct hvc_iucv_private *priv;
1051	char name[9];
1052	int rc;
1053
1054	priv = kzalloc(sizeof(struct hvc_iucv_private), GFP_KERNEL);
1055	if (!priv)
1056		return -ENOMEM;
1057
1058	spin_lock_init(&priv->lock);
1059	INIT_LIST_HEAD(&priv->tty_outqueue);
1060	INIT_LIST_HEAD(&priv->tty_inqueue);
1061	INIT_DELAYED_WORK(&priv->sndbuf_work, hvc_iucv_sndbuf_work);
1062	init_waitqueue_head(&priv->sndbuf_waitq);
1063
1064	priv->sndbuf = (void *) get_zeroed_page(GFP_KERNEL);
1065	if (!priv->sndbuf) {
1066		kfree(priv);
1067		return -ENOMEM;
1068	}
1069
1070	/* set console flag */
1071	priv->is_console = is_console;
1072
1073	/* allocate hvc device */
1074	priv->hvc = hvc_alloc(id, /*		 PAGE_SIZE */
1075			      id, &hvc_iucv_ops, 256);
1076	if (IS_ERR(priv->hvc)) {
1077		rc = PTR_ERR(priv->hvc);
1078		goto out_error_hvc;
1079	}
1080
1081	/* notify HVC thread instead of using polling */
1082	priv->hvc->irq_requested = 1;
1083
1084	/* setup iucv related information */
1085	snprintf(name, 9, "lnxhvc%-2d", id);
1086	memcpy(priv->srv_name, name, 8);
1087	ASCEBC(priv->srv_name, 8);
1088
1089	priv->dev = iucv_alloc_device(hvc_iucv_dev_attr_groups, NULL,
1090				      priv, "hvc_iucv%d", id);
1091	if (!priv->dev) {
1092		rc = -ENOMEM;
1093		goto out_error_dev;
1094	}
1095	rc = device_register(priv->dev);
1096	if (rc) {
1097		put_device(priv->dev);
1098		goto out_error_dev;
1099	}
1100
1101	hvc_iucv_table[id] = priv;
1102	return 0;
1103
1104out_error_dev:
1105	hvc_remove(priv->hvc);
1106out_error_hvc:
1107	free_page((unsigned long) priv->sndbuf);
1108	kfree(priv);
1109
1110	return rc;
1111}
1112
1113/**
1114 * hvc_iucv_destroy() - Destroy and free hvc_iucv_private instances
1115 */
1116static void __init hvc_iucv_destroy(struct hvc_iucv_private *priv)
1117{
1118	hvc_remove(priv->hvc);
1119	device_unregister(priv->dev);
1120	free_page((unsigned long) priv->sndbuf);
1121	kfree(priv);
1122}
1123
1124/**
1125 * hvc_iucv_parse_filter() - Parse filter for a single z/VM user ID
1126 * @filter:	String containing a comma-separated list of z/VM user IDs
1127 * @dest:	Location where to store the parsed z/VM user ID
1128 */
1129static const char *hvc_iucv_parse_filter(const char *filter, char *dest)
1130{
1131	const char *nextdelim, *residual;
1132	size_t len;
1133
1134	nextdelim = strchr(filter, ',');
1135	if (nextdelim) {
1136		len = nextdelim - filter;
1137		residual = nextdelim + 1;
1138	} else {
1139		len = strlen(filter);
1140		residual = filter + len;
1141	}
1142
1143	if (len == 0)
1144		return ERR_PTR(-EINVAL);
1145
1146	/* check for '\n' (if called from sysfs) */
1147	if (filter[len - 1] == '\n')
1148		len--;
1149
1150	/* prohibit filter entries containing the wildcard character only */
1151	if (len == 1 && *filter == FILTER_WILDCARD_CHAR)
1152		return ERR_PTR(-EINVAL);
1153
1154	if (len > 8)
1155		return ERR_PTR(-EINVAL);
1156
1157	/* pad with blanks and save upper case version of user ID */
1158	memset(dest, ' ', 8);
1159	while (len--)
1160		dest[len] = toupper(filter[len]);
1161	return residual;
1162}
1163
1164/**
1165 * hvc_iucv_setup_filter() - Set up z/VM user ID filter
1166 * @filter:	String consisting of a comma-separated list of z/VM user IDs
1167 *
1168 * The function parses the @filter string and creates an array containing
1169 * the list of z/VM user ID filter entries.
1170 * Return code 0 means success, -EINVAL if the filter is syntactically
1171 * incorrect, -ENOMEM if there was not enough memory to allocate the
1172 * filter list array, or -ENOSPC if too many z/VM user IDs have been specified.
1173 */
1174static int hvc_iucv_setup_filter(const char *val)
1175{
1176	const char *residual;
1177	int err;
1178	size_t size, count;
1179	void *array, *old_filter;
1180
1181	count = strlen(val);
1182	if (count == 0 || (count == 1 && val[0] == '\n')) {
1183		size  = 0;
1184		array = NULL;
1185		goto out_replace_filter;	/* clear filter */
1186	}
1187
1188	/* count user IDs in order to allocate sufficient memory */
1189	size = 1;
1190	residual = val;
1191	while ((residual = strchr(residual, ',')) != NULL) {
1192		residual++;
1193		size++;
1194	}
1195
1196	/* check if the specified list exceeds the filter limit */
1197	if (size > MAX_VMID_FILTER)
1198		return -ENOSPC;
1199
1200	array = kcalloc(size, 8, GFP_KERNEL);
1201	if (!array)
1202		return -ENOMEM;
1203
1204	count = size;
1205	residual = val;
1206	while (*residual && count) {
1207		residual = hvc_iucv_parse_filter(residual,
1208						 array + ((size - count) * 8));
1209		if (IS_ERR(residual)) {
1210			err = PTR_ERR(residual);
1211			kfree(array);
1212			goto out_err;
1213		}
1214		count--;
1215	}
1216
1217out_replace_filter:
1218	write_lock_bh(&hvc_iucv_filter_lock);
1219	old_filter = hvc_iucv_filter;
1220	hvc_iucv_filter_size = size;
1221	hvc_iucv_filter = array;
1222	write_unlock_bh(&hvc_iucv_filter_lock);
1223	kfree(old_filter);
1224
1225	err = 0;
1226out_err:
1227	return err;
1228}
1229
1230/**
1231 * param_set_vmidfilter() - Set z/VM user ID filter parameter
1232 * @val:	String consisting of a comma-separated list of z/VM user IDs
1233 * @kp:		Kernel parameter pointing to hvc_iucv_filter array
1234 *
1235 * The function sets up the z/VM user ID filter specified as comma-separated
1236 * list of user IDs in @val.
1237 * Note: If it is called early in the boot process, @val is stored and
1238 *	 parsed later in hvc_iucv_init().
1239 */
1240static int param_set_vmidfilter(const char *val, const struct kernel_param *kp)
1241{
1242	int rc;
1243
1244	if (!machine_is_vm() || !hvc_iucv_devices)
1245		return -ENODEV;
1246
1247	if (!val)
1248		return -EINVAL;
1249
1250	rc = 0;
1251	if (slab_is_available())
1252		rc = hvc_iucv_setup_filter(val);
1253	else
1254		hvc_iucv_filter_string = val;	/* defer... */
1255	return rc;
1256}
1257
1258/**
1259 * param_get_vmidfilter() - Get z/VM user ID filter
1260 * @buffer:	Buffer to store z/VM user ID filter,
1261 *		(buffer size assumption PAGE_SIZE)
1262 * @kp:		Kernel parameter pointing to the hvc_iucv_filter array
1263 *
1264 * The function stores the filter as a comma-separated list of z/VM user IDs
1265 * in @buffer. Typically, sysfs routines call this function for attr show.
1266 */
1267static int param_get_vmidfilter(char *buffer, const struct kernel_param *kp)
1268{
1269	int rc;
1270	size_t index, len;
1271	void *start, *end;
1272
1273	if (!machine_is_vm() || !hvc_iucv_devices)
1274		return -ENODEV;
1275
1276	rc = 0;
1277	read_lock_bh(&hvc_iucv_filter_lock);
1278	for (index = 0; index < hvc_iucv_filter_size; index++) {
1279		start = hvc_iucv_filter + (8 * index);
1280		end   = memchr(start, ' ', 8);
1281		len   = (end) ? end - start : 8;
1282		memcpy(buffer + rc, start, len);
1283		rc += len;
1284		buffer[rc++] = ',';
1285	}
1286	read_unlock_bh(&hvc_iucv_filter_lock);
1287	if (rc)
1288		buffer[--rc] = '\0';	/* replace last comma and update rc */
1289	return rc;
1290}
1291
1292#define param_check_vmidfilter(name, p) __param_check(name, p, void)
1293
1294static const struct kernel_param_ops param_ops_vmidfilter = {
1295	.set = param_set_vmidfilter,
1296	.get = param_get_vmidfilter,
1297};
1298
1299/**
1300 * hvc_iucv_init() - z/VM IUCV HVC device driver initialization
1301 */
1302static int __init hvc_iucv_init(void)
1303{
1304	int rc;
1305	unsigned int i;
1306
1307	if (!hvc_iucv_devices)
1308		return -ENODEV;
1309
1310	if (!machine_is_vm()) {
1311		pr_notice("The z/VM IUCV HVC device driver cannot "
1312			   "be used without z/VM\n");
1313		rc = -ENODEV;
1314		goto out_error;
1315	}
1316
1317	if (hvc_iucv_devices > MAX_HVC_IUCV_LINES) {
1318		pr_err("%lu is not a valid value for the hvc_iucv= "
1319			"kernel parameter\n", hvc_iucv_devices);
1320		rc = -EINVAL;
1321		goto out_error;
1322	}
1323
1324	/* parse hvc_iucv_allow string and create z/VM user ID filter list */
1325	if (hvc_iucv_filter_string) {
1326		rc = hvc_iucv_setup_filter(hvc_iucv_filter_string);
1327		switch (rc) {
1328		case 0:
1329			break;
1330		case -ENOMEM:
1331			pr_err("Allocating memory failed with "
1332				"reason code=%d\n", 3);
1333			goto out_error;
1334		case -EINVAL:
1335			pr_err("hvc_iucv_allow= does not specify a valid "
1336				"z/VM user ID list\n");
1337			goto out_error;
1338		case -ENOSPC:
1339			pr_err("hvc_iucv_allow= specifies too many "
1340				"z/VM user IDs\n");
1341			goto out_error;
1342		default:
1343			goto out_error;
1344		}
1345	}
1346
1347	hvc_iucv_buffer_cache = kmem_cache_create(KMSG_COMPONENT,
1348					   sizeof(struct iucv_tty_buffer),
1349					   0, 0, NULL);
1350	if (!hvc_iucv_buffer_cache) {
1351		pr_err("Allocating memory failed with reason code=%d\n", 1);
1352		rc = -ENOMEM;
1353		goto out_error;
1354	}
1355
1356	hvc_iucv_mempool = mempool_create_slab_pool(MEMPOOL_MIN_NR,
1357						    hvc_iucv_buffer_cache);
1358	if (!hvc_iucv_mempool) {
1359		pr_err("Allocating memory failed with reason code=%d\n", 2);
1360		kmem_cache_destroy(hvc_iucv_buffer_cache);
1361		rc = -ENOMEM;
1362		goto out_error;
1363	}
1364
1365	/* register the first terminal device as console
1366	 * (must be done before allocating hvc terminal devices) */
1367	rc = hvc_instantiate(0, IUCV_HVC_CON_IDX, &hvc_iucv_ops);
1368	if (rc) {
1369		pr_err("Registering HVC terminal device as "
1370		       "Linux console failed\n");
1371		goto out_error_memory;
1372	}
1373
1374	/* allocate hvc_iucv_private structs */
1375	for (i = 0; i < hvc_iucv_devices; i++) {
1376		rc = hvc_iucv_alloc(i, (i == IUCV_HVC_CON_IDX) ? 1 : 0);
1377		if (rc) {
1378			pr_err("Creating a new HVC terminal device "
1379				"failed with error code=%d\n", rc);
1380			goto out_error_hvc;
1381		}
1382	}
1383
1384	/* register IUCV callback handler */
1385	rc = iucv_register(&hvc_iucv_handler, 0);
1386	if (rc) {
1387		pr_err("Registering IUCV handlers failed with error code=%d\n",
1388			rc);
1389		goto out_error_hvc;
1390	}
1391
1392	return 0;
1393
1394out_error_hvc:
1395	for (i = 0; i < hvc_iucv_devices; i++)
1396		if (hvc_iucv_table[i])
1397			hvc_iucv_destroy(hvc_iucv_table[i]);
1398out_error_memory:
1399	mempool_destroy(hvc_iucv_mempool);
1400	kmem_cache_destroy(hvc_iucv_buffer_cache);
1401out_error:
1402	kfree(hvc_iucv_filter);
1403	hvc_iucv_devices = 0; /* ensure that we do not provide any device */
1404	return rc;
1405}
1406
1407/**
1408 * hvc_iucv_config() - Parsing of hvc_iucv=  kernel command line parameter
1409 * @val:	Parameter value (numeric)
1410 */
1411static	int __init hvc_iucv_config(char *val)
1412{
1413	if (kstrtoul(val, 10, &hvc_iucv_devices))
1414		pr_warn("hvc_iucv= invalid parameter value '%s'\n", val);
1415	return 1;
1416}
1417
1418
1419device_initcall(hvc_iucv_init);
1420__setup("hvc_iucv=", hvc_iucv_config);
1421core_param(hvc_iucv_allow, hvc_iucv_filter, vmidfilter, 0640);