1/*
2 * z/VM IUCV hypervisor console (HVC) device driver
3 *
4 * This HVC device driver provides terminal access using
5 * z/VM IUCV communication paths.
6 *
7 * Copyright IBM Corp. 2008, 2013
8 *
9 * Author(s):	Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
10 */
11#define KMSG_COMPONENT		"hvc_iucv"
12#define pr_fmt(fmt)		KMSG_COMPONENT ": " fmt
13
14#include <linux/types.h>
15#include <linux/slab.h>
16#include <asm/ebcdic.h>
17#include <linux/ctype.h>
18#include <linux/delay.h>
19#include <linux/device.h>
20#include <linux/init.h>
21#include <linux/mempool.h>
22#include <linux/moduleparam.h>
23#include <linux/tty.h>
24#include <linux/wait.h>
25#include <net/iucv/iucv.h>
26
27#include "hvc_console.h"
28
29
30/* General device driver settings */
31#define HVC_IUCV_MAGIC		0xc9e4c3e5
32#define MAX_HVC_IUCV_LINES	HVC_ALLOC_TTY_ADAPTERS
33#define MEMPOOL_MIN_NR		(PAGE_SIZE / sizeof(struct iucv_tty_buffer)/4)
34
35/* IUCV TTY message  */
36#define MSG_VERSION		0x02	/* Message version */
37#define MSG_TYPE_ERROR		0x01	/* Error message */
38#define MSG_TYPE_TERMENV	0x02	/* Terminal environment variable */
39#define MSG_TYPE_TERMIOS	0x04	/* Terminal IO struct update */
40#define MSG_TYPE_WINSIZE	0x08	/* Terminal window size update */
41#define MSG_TYPE_DATA		0x10	/* Terminal data */
42
43struct iucv_tty_msg {
44	u8	version;		/* Message version */
45	u8	type;			/* Message type */
46#define MSG_MAX_DATALEN		((u16)(~0))
47	u16	datalen;		/* Payload length */
48	u8	data[];			/* Payload buffer */
49} __attribute__((packed));
50#define MSG_SIZE(s)		((s) + offsetof(struct iucv_tty_msg, data))
51
52enum iucv_state_t {
53	IUCV_DISCONN	= 0,
54	IUCV_CONNECTED	= 1,
55	IUCV_SEVERED	= 2,
56};
57
58enum tty_state_t {
59	TTY_CLOSED	= 0,
60	TTY_OPENED	= 1,
61};
62
63struct hvc_iucv_private {
64	struct hvc_struct	*hvc;		/* HVC struct reference */
65	u8			srv_name[8];	/* IUCV service name (ebcdic) */
66	unsigned char		is_console;	/* Linux console usage flag */
67	enum iucv_state_t	iucv_state;	/* IUCV connection status */
68	enum tty_state_t	tty_state;	/* TTY status */
69	struct iucv_path	*path;		/* IUCV path pointer */
70	spinlock_t		lock;		/* hvc_iucv_private lock */
71#define SNDBUF_SIZE		(PAGE_SIZE)	/* must be < MSG_MAX_DATALEN */
72	void			*sndbuf;	/* send buffer		  */
73	size_t			sndbuf_len;	/* length of send buffer  */
74#define QUEUE_SNDBUF_DELAY	(HZ / 25)
75	struct delayed_work	sndbuf_work;	/* work: send iucv msg(s) */
76	wait_queue_head_t	sndbuf_waitq;	/* wait for send completion */
77	struct list_head	tty_outqueue;	/* outgoing IUCV messages */
78	struct list_head	tty_inqueue;	/* incoming IUCV messages */
79	struct device		*dev;		/* device structure */
80	u8			info_path[16];	/* IUCV path info (dev attr) */
81};
82
83struct iucv_tty_buffer {
84	struct list_head	list;	/* list pointer */
85	struct iucv_message	msg;	/* store an IUCV message */
86	size_t			offset;	/* data buffer offset */
87	struct iucv_tty_msg	*mbuf;	/* buffer to store input/output data */
88};
89
90/* IUCV callback handler */
91static	int hvc_iucv_path_pending(struct iucv_path *, u8[8], u8[16]);
92static void hvc_iucv_path_severed(struct iucv_path *, u8[16]);
93static void hvc_iucv_msg_pending(struct iucv_path *, struct iucv_message *);
94static void hvc_iucv_msg_complete(struct iucv_path *, struct iucv_message *);
95
96
97/* Kernel module parameter: use one terminal device as default */
98static unsigned long hvc_iucv_devices = 1;
99
100/* Array of allocated hvc iucv tty lines... */
101static struct hvc_iucv_private *hvc_iucv_table[MAX_HVC_IUCV_LINES];
102#define IUCV_HVC_CON_IDX	(0)
103/* List of z/VM user ID filter entries (struct iucv_vmid_filter) */
104#define MAX_VMID_FILTER		(500)
105#define FILTER_WILDCARD_CHAR	'*'
106static size_t hvc_iucv_filter_size;
107static void *hvc_iucv_filter;
108static const char *hvc_iucv_filter_string;
109static DEFINE_RWLOCK(hvc_iucv_filter_lock);
110
111/* Kmem cache and mempool for iucv_tty_buffer elements */
112static struct kmem_cache *hvc_iucv_buffer_cache;
113static mempool_t *hvc_iucv_mempool;
114
115/* IUCV handler callback functions */
116static struct iucv_handler hvc_iucv_handler = {
117	.path_pending  = hvc_iucv_path_pending,
118	.path_severed  = hvc_iucv_path_severed,
119	.message_complete = hvc_iucv_msg_complete,
120	.message_pending  = hvc_iucv_msg_pending,
121};
122
123
124/**
125 * hvc_iucv_get_private() - Return a struct hvc_iucv_private instance.
126 * @num:	The HVC virtual terminal number (vtermno)
127 *
128 * This function returns the struct hvc_iucv_private instance that corresponds
129 * to the HVC virtual terminal number specified as parameter @num.
130 */
131static struct hvc_iucv_private *hvc_iucv_get_private(uint32_t num)
132{
133	if ((num < HVC_IUCV_MAGIC) || (num - HVC_IUCV_MAGIC > hvc_iucv_devices))
134		return NULL;
135	return hvc_iucv_table[num - HVC_IUCV_MAGIC];
136}
137
138/**
139 * alloc_tty_buffer() - Return a new struct iucv_tty_buffer element.
140 * @size:	Size of the internal buffer used to store data.
141 * @flags:	Memory allocation flags passed to mempool.
142 *
143 * This function allocates a new struct iucv_tty_buffer element and, optionally,
144 * allocates an internal data buffer with the specified size @size.
145 * The internal data buffer is always allocated with GFP_DMA which is
146 * required for receiving and sending data with IUCV.
147 * Note: The total message size arises from the internal buffer size and the
148 *	 members of the iucv_tty_msg structure.
149 * The function returns NULL if memory allocation has failed.
150 */
151static struct iucv_tty_buffer *alloc_tty_buffer(size_t size, gfp_t flags)
152{
153	struct iucv_tty_buffer *bufp;
154
155	bufp = mempool_alloc(hvc_iucv_mempool, flags);
156	if (!bufp)
157		return NULL;
158	memset(bufp, 0, sizeof(*bufp));
159
160	if (size > 0) {
161		bufp->msg.length = MSG_SIZE(size);
162		bufp->mbuf = kmalloc(bufp->msg.length, flags | GFP_DMA);
163		if (!bufp->mbuf) {
164			mempool_free(bufp, hvc_iucv_mempool);
165			return NULL;
166		}
167		bufp->mbuf->version = MSG_VERSION;
168		bufp->mbuf->type    = MSG_TYPE_DATA;
169		bufp->mbuf->datalen = (u16) size;
170	}
171	return bufp;
172}
173
174/**
175 * destroy_tty_buffer() - destroy struct iucv_tty_buffer element.
176 * @bufp:	Pointer to a struct iucv_tty_buffer element, SHALL NOT be NULL.
177 */
178static void destroy_tty_buffer(struct iucv_tty_buffer *bufp)
179{
180	kfree(bufp->mbuf);
181	mempool_free(bufp, hvc_iucv_mempool);
182}
183
184/**
185 * destroy_tty_buffer_list() - call destroy_tty_buffer() for each list element.
186 * @list:	List containing struct iucv_tty_buffer elements.
187 */
188static void destroy_tty_buffer_list(struct list_head *list)
189{
190	struct iucv_tty_buffer *ent, *next;
191
192	list_for_each_entry_safe(ent, next, list, list) {
193		list_del(&ent->list);
194		destroy_tty_buffer(ent);
195	}
196}
197
198/**
199 * hvc_iucv_write() - Receive IUCV message & write data to HVC buffer.
200 * @priv:		Pointer to struct hvc_iucv_private
201 * @buf:		HVC buffer for writing received terminal data.
202 * @count:		HVC buffer size.
203 * @has_more_data:	Pointer to an int variable.
204 *
205 * The function picks up pending messages from the input queue and receives
206 * the message data that is then written to the specified buffer @buf.
207 * If the buffer size @count is less than the data message size, the
208 * message is kept on the input queue and @has_more_data is set to 1.
209 * If all message data has been written, the message is removed from
210 * the input queue.
211 *
212 * The function returns the number of bytes written to the terminal, zero if
213 * there are no pending data messages available or if there is no established
214 * IUCV path.
215 * If the IUCV path has been severed, then -EPIPE is returned to cause a
216 * hang up (that is issued by the HVC layer).
217 */
218static int hvc_iucv_write(struct hvc_iucv_private *priv,
219			  char *buf, int count, int *has_more_data)
220{
221	struct iucv_tty_buffer *rb;
222	int written;
223	int rc;
224
225	/* immediately return if there is no IUCV connection */
226	if (priv->iucv_state == IUCV_DISCONN)
227		return 0;
228
229	/* if the IUCV path has been severed, return -EPIPE to inform the
230	 * HVC layer to hang up the tty device. */
231	if (priv->iucv_state == IUCV_SEVERED)
232		return -EPIPE;
233
234	/* check if there are pending messages */
235	if (list_empty(&priv->tty_inqueue))
236		return 0;
237
238	/* receive an iucv message and flip data to the tty (ldisc) */
239	rb = list_first_entry(&priv->tty_inqueue, struct iucv_tty_buffer, list);
240
241	written = 0;
242	if (!rb->mbuf) { /* message not yet received ... */
243		/* allocate mem to store msg data; if no memory is available
244		 * then leave the buffer on the list and re-try later */
245		rb->mbuf = kmalloc(rb->msg.length, GFP_ATOMIC | GFP_DMA);
246		if (!rb->mbuf)
247			return -ENOMEM;
248
249		rc = __iucv_message_receive(priv->path, &rb->msg, 0,
250					    rb->mbuf, rb->msg.length, NULL);
251		switch (rc) {
252		case 0: /* Successful	    */
253			break;
254		case 2:	/* No message found */
255		case 9: /* Message purged   */
256			break;
257		default:
258			written = -EIO;
259		}
260		/* remove buffer if an error has occurred or received data
261		 * is not correct */
262		if (rc || (rb->mbuf->version != MSG_VERSION) ||
263			  (rb->msg.length    != MSG_SIZE(rb->mbuf->datalen)))
264			goto out_remove_buffer;
265	}
266
267	switch (rb->mbuf->type) {
268	case MSG_TYPE_DATA:
269		written = min_t(int, rb->mbuf->datalen - rb->offset, count);
270		memcpy(buf, rb->mbuf->data + rb->offset, written);
271		if (written < (rb->mbuf->datalen - rb->offset)) {
272			rb->offset += written;
273			*has_more_data = 1;
274			goto out_written;
275		}
276		break;
277
278	case MSG_TYPE_WINSIZE:
279		if (rb->mbuf->datalen != sizeof(struct winsize))
280			break;
281		/* The caller must ensure that the hvc is locked, which
282		 * is the case when called from hvc_iucv_get_chars() */
283		__hvc_resize(priv->hvc, *((struct winsize *) rb->mbuf->data));
284		break;
285
286	case MSG_TYPE_ERROR:	/* ignored ... */
287	case MSG_TYPE_TERMENV:	/* ignored ... */
288	case MSG_TYPE_TERMIOS:	/* ignored ... */
289		break;
290	}
291
292out_remove_buffer:
293	list_del(&rb->list);
294	destroy_tty_buffer(rb);
295	*has_more_data = !list_empty(&priv->tty_inqueue);
296
297out_written:
298	return written;
299}
300
301/**
302 * hvc_iucv_get_chars() - HVC get_chars operation.
303 * @vtermno:	HVC virtual terminal number.
304 * @buf:	Pointer to a buffer to store data
305 * @count:	Size of buffer available for writing
306 *
307 * The HVC thread calls this method to read characters from the back-end.
308 * If an IUCV communication path has been established, pending IUCV messages
309 * are received and data is copied into buffer @buf up to @count bytes.
310 *
311 * Locking:	The routine gets called under an irqsave() spinlock; and
312 *		the routine locks the struct hvc_iucv_private->lock to call
313 *		helper functions.
314 */
315static int hvc_iucv_get_chars(uint32_t vtermno, char *buf, int count)
316{
317	struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
318	int written;
319	int has_more_data;
320
321	if (count <= 0)
322		return 0;
323
324	if (!priv)
325		return -ENODEV;
326
327	spin_lock(&priv->lock);
328	has_more_data = 0;
329	written = hvc_iucv_write(priv, buf, count, &has_more_data);
330	spin_unlock(&priv->lock);
331
332	/* if there are still messages on the queue... schedule another run */
333	if (has_more_data)
334		hvc_kick();
335
336	return written;
337}
338
339/**
340 * hvc_iucv_queue() - Buffer terminal data for sending.
341 * @priv:	Pointer to struct hvc_iucv_private instance.
342 * @buf:	Buffer containing data to send.
343 * @count:	Size of buffer and amount of data to send.
344 *
345 * The function queues data for sending. To actually send the buffered data,
346 * a work queue function is scheduled (with QUEUE_SNDBUF_DELAY).
347 * The function returns the number of data bytes that has been buffered.
348 *
349 * If the device is not connected, data is ignored and the function returns
350 * @count.
351 * If the buffer is full, the function returns 0.
352 * If an existing IUCV communicaton path has been severed, -EPIPE is returned
353 * (that can be passed to HVC layer to cause a tty hangup).
354 */
355static int hvc_iucv_queue(struct hvc_iucv_private *priv, const char *buf,
356			  int count)
357{
358	size_t len;
359
360	if (priv->iucv_state == IUCV_DISCONN)
361		return count;			/* ignore data */
362
363	if (priv->iucv_state == IUCV_SEVERED)
364		return -EPIPE;
365
366	len = min_t(size_t, count, SNDBUF_SIZE - priv->sndbuf_len);
367	if (!len)
368		return 0;
369
370	memcpy(priv->sndbuf + priv->sndbuf_len, buf, len);
371	priv->sndbuf_len += len;
372
373	if (priv->iucv_state == IUCV_CONNECTED)
374		schedule_delayed_work(&priv->sndbuf_work, QUEUE_SNDBUF_DELAY);
375
376	return len;
377}
378
379/**
380 * hvc_iucv_send() - Send an IUCV message containing terminal data.
381 * @priv:	Pointer to struct hvc_iucv_private instance.
382 *
383 * If an IUCV communication path has been established, the buffered output data
384 * is sent via an IUCV message and the number of bytes sent is returned.
385 * Returns 0 if there is no established IUCV communication path or
386 * -EPIPE if an existing IUCV communicaton path has been severed.
387 */
388static int hvc_iucv_send(struct hvc_iucv_private *priv)
389{
390	struct iucv_tty_buffer *sb;
391	int rc, len;
392
393	if (priv->iucv_state == IUCV_SEVERED)
394		return -EPIPE;
395
396	if (priv->iucv_state == IUCV_DISCONN)
397		return -EIO;
398
399	if (!priv->sndbuf_len)
400		return 0;
401
402	/* allocate internal buffer to store msg data and also compute total
403	 * message length */
404	sb = alloc_tty_buffer(priv->sndbuf_len, GFP_ATOMIC);
405	if (!sb)
406		return -ENOMEM;
407
408	memcpy(sb->mbuf->data, priv->sndbuf, priv->sndbuf_len);
409	sb->mbuf->datalen = (u16) priv->sndbuf_len;
410	sb->msg.length = MSG_SIZE(sb->mbuf->datalen);
411
412	list_add_tail(&sb->list, &priv->tty_outqueue);
413
414	rc = __iucv_message_send(priv->path, &sb->msg, 0, 0,
415				 (void *) sb->mbuf, sb->msg.length);
416	if (rc) {
417		/* drop the message here; however we might want to handle
418		 * 0x03 (msg limit reached) by trying again... */
419		list_del(&sb->list);
420		destroy_tty_buffer(sb);
421	}
422	len = priv->sndbuf_len;
423	priv->sndbuf_len = 0;
424
425	return len;
426}
427
428/**
429 * hvc_iucv_sndbuf_work() - Send buffered data over IUCV
430 * @work:	Work structure.
431 *
432 * This work queue function sends buffered output data over IUCV and,
433 * if not all buffered data could be sent, reschedules itself.
434 */
435static void hvc_iucv_sndbuf_work(struct work_struct *work)
436{
437	struct hvc_iucv_private *priv;
438
439	priv = container_of(work, struct hvc_iucv_private, sndbuf_work.work);
440	if (!priv)
441		return;
442
443	spin_lock_bh(&priv->lock);
444	hvc_iucv_send(priv);
445	spin_unlock_bh(&priv->lock);
446}
447
448/**
449 * hvc_iucv_put_chars() - HVC put_chars operation.
450 * @vtermno:	HVC virtual terminal number.
451 * @buf:	Pointer to an buffer to read data from
452 * @count:	Size of buffer available for reading
453 *
454 * The HVC thread calls this method to write characters to the back-end.
455 * The function calls hvc_iucv_queue() to queue terminal data for sending.
456 *
457 * Locking:	The method gets called under an irqsave() spinlock; and
458 *		locks struct hvc_iucv_private->lock.
459 */
460static int hvc_iucv_put_chars(uint32_t vtermno, const char *buf, int count)
461{
462	struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
463	int queued;
464
465	if (count <= 0)
466		return 0;
467
468	if (!priv)
469		return -ENODEV;
470
471	spin_lock(&priv->lock);
472	queued = hvc_iucv_queue(priv, buf, count);
473	spin_unlock(&priv->lock);
474
475	return queued;
476}
477
478/**
479 * hvc_iucv_notifier_add() - HVC notifier for opening a TTY for the first time.
480 * @hp:	Pointer to the HVC device (struct hvc_struct)
481 * @id:	Additional data (originally passed to hvc_alloc): the index of an struct
482 *	hvc_iucv_private instance.
483 *
484 * The function sets the tty state to TTY_OPENED for the struct hvc_iucv_private
485 * instance that is derived from @id. Always returns 0.
486 *
487 * Locking:	struct hvc_iucv_private->lock, spin_lock_bh
488 */
489static int hvc_iucv_notifier_add(struct hvc_struct *hp, int id)
490{
491	struct hvc_iucv_private *priv;
492
493	priv = hvc_iucv_get_private(id);
494	if (!priv)
495		return 0;
496
497	spin_lock_bh(&priv->lock);
498	priv->tty_state = TTY_OPENED;
499	spin_unlock_bh(&priv->lock);
500
501	return 0;
502}
503
504/**
505 * hvc_iucv_cleanup() - Clean up and reset a z/VM IUCV HVC instance.
506 * @priv:	Pointer to the struct hvc_iucv_private instance.
507 */
508static void hvc_iucv_cleanup(struct hvc_iucv_private *priv)
509{
510	destroy_tty_buffer_list(&priv->tty_outqueue);
511	destroy_tty_buffer_list(&priv->tty_inqueue);
512
513	priv->tty_state = TTY_CLOSED;
514	priv->iucv_state = IUCV_DISCONN;
515
516	priv->sndbuf_len = 0;
517}
518
519/**
520 * tty_outqueue_empty() - Test if the tty outq is empty
521 * @priv:	Pointer to struct hvc_iucv_private instance.
522 */
523static inline int tty_outqueue_empty(struct hvc_iucv_private *priv)
524{
525	int rc;
526
527	spin_lock_bh(&priv->lock);
528	rc = list_empty(&priv->tty_outqueue);
529	spin_unlock_bh(&priv->lock);
530
531	return rc;
532}
533
534/**
535 * flush_sndbuf_sync() - Flush send buffer and wait for completion
536 * @priv:	Pointer to struct hvc_iucv_private instance.
537 *
538 * The routine cancels a pending sndbuf work, calls hvc_iucv_send()
539 * to flush any buffered terminal output data and waits for completion.
540 */
541static void flush_sndbuf_sync(struct hvc_iucv_private *priv)
542{
543	int sync_wait;
544
545	cancel_delayed_work_sync(&priv->sndbuf_work);
546
547	spin_lock_bh(&priv->lock);
548	hvc_iucv_send(priv);		/* force sending buffered data */
549	sync_wait = !list_empty(&priv->tty_outqueue); /* anything queued ? */
550	spin_unlock_bh(&priv->lock);
551
552	if (sync_wait)
553		wait_event_timeout(priv->sndbuf_waitq,
554				   tty_outqueue_empty(priv), HZ/10);
555}
556
557/**
558 * hvc_iucv_hangup() - Sever IUCV path and schedule hvc tty hang up
559 * @priv:	Pointer to hvc_iucv_private structure
560 *
561 * This routine severs an existing IUCV communication path and hangs
562 * up the underlying HVC terminal device.
563 * The hang-up occurs only if an IUCV communication path is established;
564 * otherwise there is no need to hang up the terminal device.
565 *
566 * The IUCV HVC hang-up is separated into two steps:
567 * 1. After the IUCV path has been severed, the iucv_state is set to
568 *    IUCV_SEVERED.
569 * 2. Later, when the HVC thread calls hvc_iucv_get_chars(), the
570 *    IUCV_SEVERED state causes the tty hang-up in the HVC layer.
571 *
572 * If the tty has not yet been opened, clean up the hvc_iucv_private
573 * structure to allow re-connects.
574 * If the tty has been opened, let get_chars() return -EPIPE to signal
575 * the HVC layer to hang up the tty and, if so, wake up the HVC thread
576 * to call get_chars()...
577 *
578 * Special notes on hanging up a HVC terminal instantiated as console:
579 * Hang-up:	1. do_tty_hangup() replaces file ops (= hung_up_tty_fops)
580 *		2. do_tty_hangup() calls tty->ops->close() for console_filp
581 *			=> no hangup notifier is called by HVC (default)
582 *		2. hvc_close() returns because of tty_hung_up_p(filp)
583 *			=> no delete notifier is called!
584 * Finally, the back-end is not being notified, thus, the tty session is
585 * kept active (TTY_OPEN) to be ready for re-connects.
586 *
587 * Locking:	spin_lock(&priv->lock) w/o disabling bh
588 */
589static void hvc_iucv_hangup(struct hvc_iucv_private *priv)
590{
591	struct iucv_path *path;
592
593	path = NULL;
594	spin_lock(&priv->lock);
595	if (priv->iucv_state == IUCV_CONNECTED) {
596		path = priv->path;
597		priv->path = NULL;
598		priv->iucv_state = IUCV_SEVERED;
599		if (priv->tty_state == TTY_CLOSED)
600			hvc_iucv_cleanup(priv);
601		else
602			/* console is special (see above) */
603			if (priv->is_console) {
604				hvc_iucv_cleanup(priv);
605				priv->tty_state = TTY_OPENED;
606			} else
607				hvc_kick();
608	}
609	spin_unlock(&priv->lock);
610
611	/* finally sever path (outside of priv->lock due to lock ordering) */
612	if (path) {
613		iucv_path_sever(path, NULL);
614		iucv_path_free(path);
615	}
616}
617
618/**
619 * hvc_iucv_notifier_hangup() - HVC notifier for TTY hangups.
620 * @hp:		Pointer to the HVC device (struct hvc_struct)
621 * @id:		Additional data (originally passed to hvc_alloc):
622 *		the index of an struct hvc_iucv_private instance.
623 *
624 * This routine notifies the HVC back-end that a tty hangup (carrier loss,
625 * virtual or otherwise) has occurred.
626 * The z/VM IUCV HVC device driver ignores virtual hangups (vhangup())
627 * to keep an existing IUCV communication path established.
628 * (Background: vhangup() is called from user space (by getty or login) to
629 *		disable writing to the tty by other applications).
630 * If the tty has been opened and an established IUCV path has been severed
631 * (we caused the tty hangup), the function calls hvc_iucv_cleanup().
632 *
633 * Locking:	struct hvc_iucv_private->lock
634 */
635static void hvc_iucv_notifier_hangup(struct hvc_struct *hp, int id)
636{
637	struct hvc_iucv_private *priv;
638
639	priv = hvc_iucv_get_private(id);
640	if (!priv)
641		return;
642
643	flush_sndbuf_sync(priv);
644
645	spin_lock_bh(&priv->lock);
646	/* NOTE: If the hangup was scheduled by ourself (from the iucv
647	 *	 path_servered callback [IUCV_SEVERED]), we have to clean up
648	 *	 our structure and to set state to TTY_CLOSED.
649	 *	 If the tty was hung up otherwise (e.g. vhangup()), then we
650	 *	 ignore this hangup and keep an established IUCV path open...
651	 *	 (...the reason is that we are not able to connect back to the
652	 *	 client if we disconnect on hang up) */
653	priv->tty_state = TTY_CLOSED;
654
655	if (priv->iucv_state == IUCV_SEVERED)
656		hvc_iucv_cleanup(priv);
657	spin_unlock_bh(&priv->lock);
658}
659
660/**
661 * hvc_iucv_dtr_rts() - HVC notifier for handling DTR/RTS
662 * @hp:		Pointer the HVC device (struct hvc_struct)
663 * @raise:	Non-zero to raise or zero to lower DTR/RTS lines
664 *
665 * This routine notifies the HVC back-end to raise or lower DTR/RTS
666 * lines.  Raising DTR/RTS is ignored.  Lowering DTR/RTS indicates to
667 * drop the IUCV connection (similar to hang up the modem).
668 */
669static void hvc_iucv_dtr_rts(struct hvc_struct *hp, int raise)
670{
671	struct hvc_iucv_private *priv;
672	struct iucv_path        *path;
673
674	/* Raising the DTR/RTS is ignored as IUCV connections can be
675	 * established at any times.
676	 */
677	if (raise)
678		return;
679
680	priv = hvc_iucv_get_private(hp->vtermno);
681	if (!priv)
682		return;
683
684	/* Lowering the DTR/RTS lines disconnects an established IUCV
685	 * connection.
686	 */
687	flush_sndbuf_sync(priv);
688
689	spin_lock_bh(&priv->lock);
690	path = priv->path;		/* save reference to IUCV path */
691	priv->path = NULL;
692	priv->iucv_state = IUCV_DISCONN;
693	spin_unlock_bh(&priv->lock);
694
695	/* Sever IUCV path outside of priv->lock due to lock ordering of:
696	 * priv->lock <--> iucv_table_lock */
697	if (path) {
698		iucv_path_sever(path, NULL);
699		iucv_path_free(path);
700	}
701}
702
703/**
704 * hvc_iucv_notifier_del() - HVC notifier for closing a TTY for the last time.
705 * @hp:		Pointer to the HVC device (struct hvc_struct)
706 * @id:		Additional data (originally passed to hvc_alloc):
707 *		the index of an struct hvc_iucv_private instance.
708 *
709 * This routine notifies the HVC back-end that the last tty device fd has been
710 * closed.  The function cleans up tty resources.  The clean-up of the IUCV
711 * connection is done in hvc_iucv_dtr_rts() and depends on the HUPCL termios
712 * control setting.
713 *
714 * Locking:	struct hvc_iucv_private->lock
715 */
716static void hvc_iucv_notifier_del(struct hvc_struct *hp, int id)
717{
718	struct hvc_iucv_private *priv;
719
720	priv = hvc_iucv_get_private(id);
721	if (!priv)
722		return;
723
724	flush_sndbuf_sync(priv);
725
726	spin_lock_bh(&priv->lock);
727	destroy_tty_buffer_list(&priv->tty_outqueue);
728	destroy_tty_buffer_list(&priv->tty_inqueue);
729	priv->tty_state = TTY_CLOSED;
730	priv->sndbuf_len = 0;
731	spin_unlock_bh(&priv->lock);
732}
733
734/**
735 * hvc_iucv_filter_connreq() - Filter connection request based on z/VM user ID
736 * @ipvmid:	Originating z/VM user ID (right padded with blanks)
737 *
738 * Returns 0 if the z/VM user ID that is specified with @ipvmid is permitted to
739 * connect, otherwise non-zero.
740 */
741static int hvc_iucv_filter_connreq(u8 ipvmid[8])
742{
743	const char *wildcard, *filter_entry;
744	size_t i, len;
745
746	/* Note: default policy is ACCEPT if no filter is set */
747	if (!hvc_iucv_filter_size)
748		return 0;
749
750	for (i = 0; i < hvc_iucv_filter_size; i++) {
751		filter_entry = hvc_iucv_filter + (8 * i);
752
753		/* If a filter entry contains the filter wildcard character,
754		 * reduce the length to match the leading portion of the user
755		 * ID only (wildcard match).  Characters following the wildcard
756		 * are ignored.
757		 */
758		wildcard = strnchr(filter_entry, 8, FILTER_WILDCARD_CHAR);
759		len = (wildcard) ? wildcard - filter_entry : 8;
760		if (0 == memcmp(ipvmid, filter_entry, len))
761			return 0;
762	}
763	return 1;
764}
765
766/**
767 * hvc_iucv_path_pending() - IUCV handler to process a connection request.
768 * @path:	Pending path (struct iucv_path)
769 * @ipvmid:	z/VM system identifier of originator
770 * @ipuser:	User specified data for this path
771 *		(AF_IUCV: port/service name and originator port)
772 *
773 * The function uses the @ipuser data to determine if the pending path belongs
774 * to a terminal managed by this device driver.
775 * If the path belongs to this driver, ensure that the terminal is not accessed
776 * multiple times (only one connection to a terminal is allowed).
777 * If the terminal is not yet connected, the pending path is accepted and is
778 * associated to the appropriate struct hvc_iucv_private instance.
779 *
780 * Returns 0 if @path belongs to a terminal managed by the this device driver;
781 * otherwise returns -ENODEV in order to dispatch this path to other handlers.
782 *
783 * Locking:	struct hvc_iucv_private->lock
784 */
785static	int hvc_iucv_path_pending(struct iucv_path *path,
786				  u8 ipvmid[8], u8 ipuser[16])
787{
788	struct hvc_iucv_private *priv, *tmp;
789	u8 wildcard[9] = "lnxhvc  ";
790	int i, rc, find_unused;
791	u8 nuser_data[16];
792	u8 vm_user_id[9];
793
794	ASCEBC(wildcard, sizeof(wildcard));
795	find_unused = !memcmp(wildcard, ipuser, 8);
796
797	/* First, check if the pending path request is managed by this
798	 * IUCV handler:
799	 * - find a disconnected device if ipuser contains the wildcard
800	 * - find the device that matches the terminal ID in ipuser
801	 */
802	priv = NULL;
803	for (i = 0; i < hvc_iucv_devices; i++) {
804		tmp = hvc_iucv_table[i];
805		if (!tmp)
806			continue;
807
808		if (find_unused) {
809			spin_lock(&tmp->lock);
810			if (tmp->iucv_state == IUCV_DISCONN)
811				priv = tmp;
812			spin_unlock(&tmp->lock);
813
814		} else if (!memcmp(tmp->srv_name, ipuser, 8))
815				priv = tmp;
816		if (priv)
817			break;
818	}
819	if (!priv)
820		return -ENODEV;
821
822	/* Enforce that ipvmid is allowed to connect to us */
823	read_lock(&hvc_iucv_filter_lock);
824	rc = hvc_iucv_filter_connreq(ipvmid);
825	read_unlock(&hvc_iucv_filter_lock);
826	if (rc) {
827		iucv_path_sever(path, ipuser);
828		iucv_path_free(path);
829		memcpy(vm_user_id, ipvmid, 8);
830		vm_user_id[8] = 0;
831		pr_info("A connection request from z/VM user ID %s "
832			"was refused\n", vm_user_id);
833		return 0;
834	}
835
836	spin_lock(&priv->lock);
837
838	/* If the terminal is already connected or being severed, then sever
839	 * this path to enforce that there is only ONE established communication
840	 * path per terminal. */
841	if (priv->iucv_state != IUCV_DISCONN) {
842		iucv_path_sever(path, ipuser);
843		iucv_path_free(path);
844		goto out_path_handled;
845	}
846
847	/* accept path */
848	memcpy(nuser_data, ipuser + 8, 8);  /* remote service (for af_iucv) */
849	memcpy(nuser_data + 8, ipuser, 8);  /* local service  (for af_iucv) */
850	path->msglim = 0xffff;		    /* IUCV MSGLIMIT */
851	path->flags &= ~IUCV_IPRMDATA;	    /* TODO: use IUCV_IPRMDATA */
852	rc = iucv_path_accept(path, &hvc_iucv_handler, nuser_data, priv);
853	if (rc) {
854		iucv_path_sever(path, ipuser);
855		iucv_path_free(path);
856		goto out_path_handled;
857	}
858	priv->path = path;
859	priv->iucv_state = IUCV_CONNECTED;
860
861	/* store path information */
862	memcpy(priv->info_path, ipvmid, 8);
863	memcpy(priv->info_path + 8, ipuser + 8, 8);
864
865	/* flush buffered output data... */
866	schedule_delayed_work(&priv->sndbuf_work, 5);
867
868out_path_handled:
869	spin_unlock(&priv->lock);
870	return 0;
871}
872
873/**
874 * hvc_iucv_path_severed() - IUCV handler to process a path sever.
875 * @path:	Pending path (struct iucv_path)
876 * @ipuser:	User specified data for this path
877 *		(AF_IUCV: port/service name and originator port)
878 *
879 * This function calls the hvc_iucv_hangup() function for the
880 * respective IUCV HVC terminal.
881 *
882 * Locking:	struct hvc_iucv_private->lock
883 */
884static void hvc_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
885{
886	struct hvc_iucv_private *priv = path->private;
887
888	hvc_iucv_hangup(priv);
889}
890
891/**
892 * hvc_iucv_msg_pending() - IUCV handler to process an incoming IUCV message.
893 * @path:	Pending path (struct iucv_path)
894 * @msg:	Pointer to the IUCV message
895 *
896 * The function puts an incoming message on the input queue for later
897 * processing (by hvc_iucv_get_chars() / hvc_iucv_write()).
898 * If the tty has not yet been opened, the message is rejected.
899 *
900 * Locking:	struct hvc_iucv_private->lock
901 */
902static void hvc_iucv_msg_pending(struct iucv_path *path,
903				 struct iucv_message *msg)
904{
905	struct hvc_iucv_private *priv = path->private;
906	struct iucv_tty_buffer *rb;
907
908	/* reject messages that exceed max size of iucv_tty_msg->datalen */
909	if (msg->length > MSG_SIZE(MSG_MAX_DATALEN)) {
910		iucv_message_reject(path, msg);
911		return;
912	}
913
914	spin_lock(&priv->lock);
915
916	/* reject messages if tty has not yet been opened */
917	if (priv->tty_state == TTY_CLOSED) {
918		iucv_message_reject(path, msg);
919		goto unlock_return;
920	}
921
922	/* allocate tty buffer to save iucv msg only */
923	rb = alloc_tty_buffer(0, GFP_ATOMIC);
924	if (!rb) {
925		iucv_message_reject(path, msg);
926		goto unlock_return;	/* -ENOMEM */
927	}
928	rb->msg = *msg;
929
930	list_add_tail(&rb->list, &priv->tty_inqueue);
931
932	hvc_kick();	/* wake up hvc thread */
933
934unlock_return:
935	spin_unlock(&priv->lock);
936}
937
938/**
939 * hvc_iucv_msg_complete() - IUCV handler to process message completion
940 * @path:	Pending path (struct iucv_path)
941 * @msg:	Pointer to the IUCV message
942 *
943 * The function is called upon completion of message delivery to remove the
944 * message from the outqueue. Additional delivery information can be found
945 * msg->audit: rejected messages (0x040000 (IPADRJCT)), and
946 *	       purged messages	 (0x010000 (IPADPGNR)).
947 *
948 * Locking:	struct hvc_iucv_private->lock
949 */
950static void hvc_iucv_msg_complete(struct iucv_path *path,
951				  struct iucv_message *msg)
952{
953	struct hvc_iucv_private *priv = path->private;
954	struct iucv_tty_buffer	*ent, *next;
955	LIST_HEAD(list_remove);
956
957	spin_lock(&priv->lock);
958	list_for_each_entry_safe(ent, next, &priv->tty_outqueue, list)
959		if (ent->msg.id == msg->id) {
960			list_move(&ent->list, &list_remove);
961			break;
962		}
963	wake_up(&priv->sndbuf_waitq);
964	spin_unlock(&priv->lock);
965	destroy_tty_buffer_list(&list_remove);
966}
967
968/**
969 * hvc_iucv_pm_freeze() - Freeze PM callback
970 * @dev:	IUVC HVC terminal device
971 *
972 * Sever an established IUCV communication path and
973 * trigger a hang-up of the underlying HVC terminal.
974 */
975static int hvc_iucv_pm_freeze(struct device *dev)
976{
977	struct hvc_iucv_private *priv = dev_get_drvdata(dev);
978
979	local_bh_disable();
980	hvc_iucv_hangup(priv);
981	local_bh_enable();
982
983	return 0;
984}
985
986/**
987 * hvc_iucv_pm_restore_thaw() - Thaw and restore PM callback
988 * @dev:	IUVC HVC terminal device
989 *
990 * Wake up the HVC thread to trigger hang-up and respective
991 * HVC back-end notifier invocations.
992 */
993static int hvc_iucv_pm_restore_thaw(struct device *dev)
994{
995	hvc_kick();
996	return 0;
997}
998
999static ssize_t hvc_iucv_dev_termid_show(struct device *dev,
1000					struct device_attribute *attr,
1001					char *buf)
1002{
1003	struct hvc_iucv_private *priv = dev_get_drvdata(dev);
1004	size_t len;
1005
1006	len = sizeof(priv->srv_name);
1007	memcpy(buf, priv->srv_name, len);
1008	EBCASC(buf, len);
1009	buf[len++] = '\n';
1010	return len;
1011}
1012
1013static ssize_t hvc_iucv_dev_state_show(struct device *dev,
1014					struct device_attribute *attr,
1015					char *buf)
1016{
1017	struct hvc_iucv_private *priv = dev_get_drvdata(dev);
1018	return sprintf(buf, "%u:%u\n", priv->iucv_state, priv->tty_state);
1019}
1020
1021static ssize_t hvc_iucv_dev_peer_show(struct device *dev,
1022				      struct device_attribute *attr,
1023				      char *buf)
1024{
1025	struct hvc_iucv_private *priv = dev_get_drvdata(dev);
1026	char vmid[9], ipuser[9];
1027
1028	memset(vmid, 0, sizeof(vmid));
1029	memset(ipuser, 0, sizeof(ipuser));
1030
1031	spin_lock_bh(&priv->lock);
1032	if (priv->iucv_state == IUCV_CONNECTED) {
1033		memcpy(vmid, priv->info_path, 8);
1034		memcpy(ipuser, priv->info_path + 8, 8);
1035	}
1036	spin_unlock_bh(&priv->lock);
1037	EBCASC(ipuser, 8);
1038
1039	return sprintf(buf, "%s:%s\n", vmid, ipuser);
1040}
1041
1042
1043/* HVC operations */
1044static const struct hv_ops hvc_iucv_ops = {
1045	.get_chars = hvc_iucv_get_chars,
1046	.put_chars = hvc_iucv_put_chars,
1047	.notifier_add = hvc_iucv_notifier_add,
1048	.notifier_del = hvc_iucv_notifier_del,
1049	.notifier_hangup = hvc_iucv_notifier_hangup,
1050	.dtr_rts = hvc_iucv_dtr_rts,
1051};
1052
1053/* Suspend / resume device operations */
1054static const struct dev_pm_ops hvc_iucv_pm_ops = {
1055	.freeze	  = hvc_iucv_pm_freeze,
1056	.thaw	  = hvc_iucv_pm_restore_thaw,
1057	.restore  = hvc_iucv_pm_restore_thaw,
1058};
1059
1060/* IUCV HVC device driver */
1061static struct device_driver hvc_iucv_driver = {
1062	.name = KMSG_COMPONENT,
1063	.bus  = &iucv_bus,
1064	.pm   = &hvc_iucv_pm_ops,
1065};
1066
1067/* IUCV HVC device attributes */
1068static DEVICE_ATTR(termid, 0640, hvc_iucv_dev_termid_show, NULL);
1069static DEVICE_ATTR(state, 0640, hvc_iucv_dev_state_show, NULL);
1070static DEVICE_ATTR(peer, 0640, hvc_iucv_dev_peer_show, NULL);
1071static struct attribute *hvc_iucv_dev_attrs[] = {
1072	&dev_attr_termid.attr,
1073	&dev_attr_state.attr,
1074	&dev_attr_peer.attr,
1075	NULL,
1076};
1077static struct attribute_group hvc_iucv_dev_attr_group = {
1078	.attrs = hvc_iucv_dev_attrs,
1079};
1080static const struct attribute_group *hvc_iucv_dev_attr_groups[] = {
1081	&hvc_iucv_dev_attr_group,
1082	NULL,
1083};
1084
1085
1086/**
1087 * hvc_iucv_alloc() - Allocates a new struct hvc_iucv_private instance
1088 * @id:			hvc_iucv_table index
1089 * @is_console:		Flag if the instance is used as Linux console
1090 *
1091 * This function allocates a new hvc_iucv_private structure and stores
1092 * the instance in hvc_iucv_table at index @id.
1093 * Returns 0 on success; otherwise non-zero.
1094 */
1095static int __init hvc_iucv_alloc(int id, unsigned int is_console)
1096{
1097	struct hvc_iucv_private *priv;
1098	char name[9];
1099	int rc;
1100
1101	priv = kzalloc(sizeof(struct hvc_iucv_private), GFP_KERNEL);
1102	if (!priv)
1103		return -ENOMEM;
1104
1105	spin_lock_init(&priv->lock);
1106	INIT_LIST_HEAD(&priv->tty_outqueue);
1107	INIT_LIST_HEAD(&priv->tty_inqueue);
1108	INIT_DELAYED_WORK(&priv->sndbuf_work, hvc_iucv_sndbuf_work);
1109	init_waitqueue_head(&priv->sndbuf_waitq);
1110
1111	priv->sndbuf = (void *) get_zeroed_page(GFP_KERNEL);
1112	if (!priv->sndbuf) {
1113		kfree(priv);
1114		return -ENOMEM;
1115	}
1116
1117	/* set console flag */
1118	priv->is_console = is_console;
1119
1120	/* allocate hvc device */
1121	priv->hvc = hvc_alloc(HVC_IUCV_MAGIC + id, /*		  PAGE_SIZE */
1122			      HVC_IUCV_MAGIC + id, &hvc_iucv_ops, 256);
1123	if (IS_ERR(priv->hvc)) {
1124		rc = PTR_ERR(priv->hvc);
1125		goto out_error_hvc;
1126	}
1127
1128	/* notify HVC thread instead of using polling */
1129	priv->hvc->irq_requested = 1;
1130
1131	/* setup iucv related information */
1132	snprintf(name, 9, "lnxhvc%-2d", id);
1133	memcpy(priv->srv_name, name, 8);
1134	ASCEBC(priv->srv_name, 8);
1135
1136	/* create and setup device */
1137	priv->dev = kzalloc(sizeof(*priv->dev), GFP_KERNEL);
1138	if (!priv->dev) {
1139		rc = -ENOMEM;
1140		goto out_error_dev;
1141	}
1142	dev_set_name(priv->dev, "hvc_iucv%d", id);
1143	dev_set_drvdata(priv->dev, priv);
1144	priv->dev->bus = &iucv_bus;
1145	priv->dev->parent = iucv_root;
1146	priv->dev->driver = &hvc_iucv_driver;
1147	priv->dev->groups = hvc_iucv_dev_attr_groups;
1148	priv->dev->release = (void (*)(struct device *)) kfree;
1149	rc = device_register(priv->dev);
1150	if (rc) {
1151		put_device(priv->dev);
1152		goto out_error_dev;
1153	}
1154
1155	hvc_iucv_table[id] = priv;
1156	return 0;
1157
1158out_error_dev:
1159	hvc_remove(priv->hvc);
1160out_error_hvc:
1161	free_page((unsigned long) priv->sndbuf);
1162	kfree(priv);
1163
1164	return rc;
1165}
1166
1167/**
1168 * hvc_iucv_destroy() - Destroy and free hvc_iucv_private instances
1169 */
1170static void __init hvc_iucv_destroy(struct hvc_iucv_private *priv)
1171{
1172	hvc_remove(priv->hvc);
1173	device_unregister(priv->dev);
1174	free_page((unsigned long) priv->sndbuf);
1175	kfree(priv);
1176}
1177
1178/**
1179 * hvc_iucv_parse_filter() - Parse filter for a single z/VM user ID
1180 * @filter:	String containing a comma-separated list of z/VM user IDs
1181 * @dest:	Location where to store the parsed z/VM user ID
1182 */
1183static const char *hvc_iucv_parse_filter(const char *filter, char *dest)
1184{
1185	const char *nextdelim, *residual;
1186	size_t len;
1187
1188	nextdelim = strchr(filter, ',');
1189	if (nextdelim) {
1190		len = nextdelim - filter;
1191		residual = nextdelim + 1;
1192	} else {
1193		len = strlen(filter);
1194		residual = filter + len;
1195	}
1196
1197	if (len == 0)
1198		return ERR_PTR(-EINVAL);
1199
1200	/* check for '\n' (if called from sysfs) */
1201	if (filter[len - 1] == '\n')
1202		len--;
1203
1204	/* prohibit filter entries containing the wildcard character only */
1205	if (len == 1 && *filter == FILTER_WILDCARD_CHAR)
1206		return ERR_PTR(-EINVAL);
1207
1208	if (len > 8)
1209		return ERR_PTR(-EINVAL);
1210
1211	/* pad with blanks and save upper case version of user ID */
1212	memset(dest, ' ', 8);
1213	while (len--)
1214		dest[len] = toupper(filter[len]);
1215	return residual;
1216}
1217
1218/**
1219 * hvc_iucv_setup_filter() - Set up z/VM user ID filter
1220 * @filter:	String consisting of a comma-separated list of z/VM user IDs
1221 *
1222 * The function parses the @filter string and creates an array containing
1223 * the list of z/VM user ID filter entries.
1224 * Return code 0 means success, -EINVAL if the filter is syntactically
1225 * incorrect, -ENOMEM if there was not enough memory to allocate the
1226 * filter list array, or -ENOSPC if too many z/VM user IDs have been specified.
1227 */
1228static int hvc_iucv_setup_filter(const char *val)
1229{
1230	const char *residual;
1231	int err;
1232	size_t size, count;
1233	void *array, *old_filter;
1234
1235	count = strlen(val);
1236	if (count == 0 || (count == 1 && val[0] == '\n')) {
1237		size  = 0;
1238		array = NULL;
1239		goto out_replace_filter;	/* clear filter */
1240	}
1241
1242	/* count user IDs in order to allocate sufficient memory */
1243	size = 1;
1244	residual = val;
1245	while ((residual = strchr(residual, ',')) != NULL) {
1246		residual++;
1247		size++;
1248	}
1249
1250	/* check if the specified list exceeds the filter limit */
1251	if (size > MAX_VMID_FILTER)
1252		return -ENOSPC;
1253
1254	array = kzalloc(size * 8, GFP_KERNEL);
1255	if (!array)
1256		return -ENOMEM;
1257
1258	count = size;
1259	residual = val;
1260	while (*residual && count) {
1261		residual = hvc_iucv_parse_filter(residual,
1262						 array + ((size - count) * 8));
1263		if (IS_ERR(residual)) {
1264			err = PTR_ERR(residual);
1265			kfree(array);
1266			goto out_err;
1267		}
1268		count--;
1269	}
1270
1271out_replace_filter:
1272	write_lock_bh(&hvc_iucv_filter_lock);
1273	old_filter = hvc_iucv_filter;
1274	hvc_iucv_filter_size = size;
1275	hvc_iucv_filter = array;
1276	write_unlock_bh(&hvc_iucv_filter_lock);
1277	kfree(old_filter);
1278
1279	err = 0;
1280out_err:
1281	return err;
1282}
1283
1284/**
1285 * param_set_vmidfilter() - Set z/VM user ID filter parameter
1286 * @val:	String consisting of a comma-separated list of z/VM user IDs
1287 * @kp:		Kernel parameter pointing to hvc_iucv_filter array
1288 *
1289 * The function sets up the z/VM user ID filter specified as comma-separated
1290 * list of user IDs in @val.
1291 * Note: If it is called early in the boot process, @val is stored and
1292 *	 parsed later in hvc_iucv_init().
1293 */
1294static int param_set_vmidfilter(const char *val, const struct kernel_param *kp)
1295{
1296	int rc;
1297
1298	if (!MACHINE_IS_VM || !hvc_iucv_devices)
1299		return -ENODEV;
1300
1301	if (!val)
1302		return -EINVAL;
1303
1304	rc = 0;
1305	if (slab_is_available())
1306		rc = hvc_iucv_setup_filter(val);
1307	else
1308		hvc_iucv_filter_string = val;	/* defer... */
1309	return rc;
1310}
1311
1312/**
1313 * param_get_vmidfilter() - Get z/VM user ID filter
1314 * @buffer:	Buffer to store z/VM user ID filter,
1315 *		(buffer size assumption PAGE_SIZE)
1316 * @kp:		Kernel parameter pointing to the hvc_iucv_filter array
1317 *
1318 * The function stores the filter as a comma-separated list of z/VM user IDs
1319 * in @buffer. Typically, sysfs routines call this function for attr show.
1320 */
1321static int param_get_vmidfilter(char *buffer, const struct kernel_param *kp)
1322{
1323	int rc;
1324	size_t index, len;
1325	void *start, *end;
1326
1327	if (!MACHINE_IS_VM || !hvc_iucv_devices)
1328		return -ENODEV;
1329
1330	rc = 0;
1331	read_lock_bh(&hvc_iucv_filter_lock);
1332	for (index = 0; index < hvc_iucv_filter_size; index++) {
1333		start = hvc_iucv_filter + (8 * index);
1334		end   = memchr(start, ' ', 8);
1335		len   = (end) ? end - start : 8;
1336		memcpy(buffer + rc, start, len);
1337		rc += len;
1338		buffer[rc++] = ',';
1339	}
1340	read_unlock_bh(&hvc_iucv_filter_lock);
1341	if (rc)
1342		buffer[--rc] = '\0';	/* replace last comma and update rc */
1343	return rc;
1344}
1345
1346#define param_check_vmidfilter(name, p) __param_check(name, p, void)
1347
1348static struct kernel_param_ops param_ops_vmidfilter = {
1349	.set = param_set_vmidfilter,
1350	.get = param_get_vmidfilter,
1351};
1352
1353/**
1354 * hvc_iucv_init() - z/VM IUCV HVC device driver initialization
1355 */
1356static int __init hvc_iucv_init(void)
1357{
1358	int rc;
1359	unsigned int i;
1360
1361	if (!hvc_iucv_devices)
1362		return -ENODEV;
1363
1364	if (!MACHINE_IS_VM) {
1365		pr_notice("The z/VM IUCV HVC device driver cannot "
1366			   "be used without z/VM\n");
1367		rc = -ENODEV;
1368		goto out_error;
1369	}
1370
1371	if (hvc_iucv_devices > MAX_HVC_IUCV_LINES) {
1372		pr_err("%lu is not a valid value for the hvc_iucv= "
1373			"kernel parameter\n", hvc_iucv_devices);
1374		rc = -EINVAL;
1375		goto out_error;
1376	}
1377
1378	/* register IUCV HVC device driver */
1379	rc = driver_register(&hvc_iucv_driver);
1380	if (rc)
1381		goto out_error;
1382
1383	/* parse hvc_iucv_allow string and create z/VM user ID filter list */
1384	if (hvc_iucv_filter_string) {
1385		rc = hvc_iucv_setup_filter(hvc_iucv_filter_string);
1386		switch (rc) {
1387		case 0:
1388			break;
1389		case -ENOMEM:
1390			pr_err("Allocating memory failed with "
1391				"reason code=%d\n", 3);
1392			goto out_error;
1393		case -EINVAL:
1394			pr_err("hvc_iucv_allow= does not specify a valid "
1395				"z/VM user ID list\n");
1396			goto out_error;
1397		case -ENOSPC:
1398			pr_err("hvc_iucv_allow= specifies too many "
1399				"z/VM user IDs\n");
1400			goto out_error;
1401		default:
1402			goto out_error;
1403		}
1404	}
1405
1406	hvc_iucv_buffer_cache = kmem_cache_create(KMSG_COMPONENT,
1407					   sizeof(struct iucv_tty_buffer),
1408					   0, 0, NULL);
1409	if (!hvc_iucv_buffer_cache) {
1410		pr_err("Allocating memory failed with reason code=%d\n", 1);
1411		rc = -ENOMEM;
1412		goto out_error;
1413	}
1414
1415	hvc_iucv_mempool = mempool_create_slab_pool(MEMPOOL_MIN_NR,
1416						    hvc_iucv_buffer_cache);
1417	if (!hvc_iucv_mempool) {
1418		pr_err("Allocating memory failed with reason code=%d\n", 2);
1419		kmem_cache_destroy(hvc_iucv_buffer_cache);
1420		rc = -ENOMEM;
1421		goto out_error;
1422	}
1423
1424	/* register the first terminal device as console
1425	 * (must be done before allocating hvc terminal devices) */
1426	rc = hvc_instantiate(HVC_IUCV_MAGIC, IUCV_HVC_CON_IDX, &hvc_iucv_ops);
1427	if (rc) {
1428		pr_err("Registering HVC terminal device as "
1429		       "Linux console failed\n");
1430		goto out_error_memory;
1431	}
1432
1433	/* allocate hvc_iucv_private structs */
1434	for (i = 0; i < hvc_iucv_devices; i++) {
1435		rc = hvc_iucv_alloc(i, (i == IUCV_HVC_CON_IDX) ? 1 : 0);
1436		if (rc) {
1437			pr_err("Creating a new HVC terminal device "
1438				"failed with error code=%d\n", rc);
1439			goto out_error_hvc;
1440		}
1441	}
1442
1443	/* register IUCV callback handler */
1444	rc = iucv_register(&hvc_iucv_handler, 0);
1445	if (rc) {
1446		pr_err("Registering IUCV handlers failed with error code=%d\n",
1447			rc);
1448		goto out_error_hvc;
1449	}
1450
1451	return 0;
1452
1453out_error_hvc:
1454	for (i = 0; i < hvc_iucv_devices; i++)
1455		if (hvc_iucv_table[i])
1456			hvc_iucv_destroy(hvc_iucv_table[i]);
1457out_error_memory:
1458	mempool_destroy(hvc_iucv_mempool);
1459	kmem_cache_destroy(hvc_iucv_buffer_cache);
1460out_error:
1461	kfree(hvc_iucv_filter);
1462	hvc_iucv_devices = 0; /* ensure that we do not provide any device */
1463	return rc;
1464}
1465
1466/**
1467 * hvc_iucv_config() - Parsing of hvc_iucv=  kernel command line parameter
1468 * @val:	Parameter value (numeric)
1469 */
1470static	int __init hvc_iucv_config(char *val)
1471{
1472	 return kstrtoul(val, 10, &hvc_iucv_devices);
1473}
1474
1475
1476device_initcall(hvc_iucv_init);
1477__setup("hvc_iucv=", hvc_iucv_config);
1478core_param(hvc_iucv_allow, hvc_iucv_filter, vmidfilter, 0640);
1479