1// SPDX-License-Identifier: GPL-2.0
2/*
3 * z/VM IUCV hypervisor console (HVC) device driver
4 *
5 * This HVC device driver provides terminal access using
6 * z/VM IUCV communication paths.
7 *
8 * Copyright IBM Corp. 2008, 2013
9 *
10 * Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
11 */
12#define KMSG_COMPONENT "hvc_iucv"
13#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
14
15#include <linux/types.h>
16#include <linux/slab.h>
17#include <asm/ebcdic.h>
18#include <linux/ctype.h>
19#include <linux/delay.h>
20#include <linux/device.h>
21#include <linux/init.h>
22#include <linux/mempool.h>
23#include <linux/moduleparam.h>
24#include <linux/tty.h>
25#include <linux/wait.h>
26#include <net/iucv/iucv.h>
27
28#include "hvc_console.h"
29
30
31/* General device driver settings */
32#define 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 *, u8 *);
92static void hvc_iucv_path_severed(struct iucv_path *, u8 *);
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_devices)
134 return NULL;
135 return hvc_iucv_table[num];
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(pool: hvc_iucv_mempool, gfp_mask: 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(size: bufp->msg.length, flags: flags | GFP_DMA);
163 if (!bufp->mbuf) {
164 mempool_free(element: bufp, pool: 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(objp: bufp->mbuf);
181 mempool_free(element: bufp, pool: 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(entry: &ent->list);
194 destroy_tty_buffer(bufp: 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(head: &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(size: rb->msg.length, GFP_ATOMIC | GFP_DMA);
246 if (!rb->mbuf)
247 return -ENOMEM;
248
249 rc = __iucv_message_receive(path: priv->path, msg: &rb->msg, flags: 0,
250 buffer: rb->mbuf, size: 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(hp: priv->hvc, ws: *((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(entry: &rb->list);
294 destroy_tty_buffer(bufp: rb);
295 *has_more_data = !list_empty(head: &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(num: 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(lock: &priv->lock);
328 has_more_data = 0;
329 written = hvc_iucv_write(priv, buf, count, has_more_data: &has_more_data);
330 spin_unlock(lock: &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(dwork: &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(size: 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(new: &sb->list, head: &priv->tty_outqueue);
413
414 rc = __iucv_message_send(path: priv->path, msg: &sb->msg, flags: 0, srccls: 0,
415 buffer: (void *) sb->mbuf, size: 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(entry: &sb->list);
420 destroy_tty_buffer(bufp: 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
441 spin_lock_bh(lock: &priv->lock);
442 hvc_iucv_send(priv);
443 spin_unlock_bh(lock: &priv->lock);
444}
445
446/**
447 * hvc_iucv_put_chars() - HVC put_chars operation.
448 * @vtermno: HVC virtual terminal number.
449 * @buf: Pointer to an buffer to read data from
450 * @count: Size of buffer available for reading
451 *
452 * The HVC thread calls this method to write characters to the back-end.
453 * The function calls hvc_iucv_queue() to queue terminal data for sending.
454 *
455 * Locking: The method gets called under an irqsave() spinlock; and
456 * locks struct hvc_iucv_private->lock.
457 */
458static int hvc_iucv_put_chars(uint32_t vtermno, const char *buf, int count)
459{
460 struct hvc_iucv_private *priv = hvc_iucv_get_private(num: vtermno);
461 int queued;
462
463 if (count <= 0)
464 return 0;
465
466 if (!priv)
467 return -ENODEV;
468
469 spin_lock(lock: &priv->lock);
470 queued = hvc_iucv_queue(priv, buf, count);
471 spin_unlock(lock: &priv->lock);
472
473 return queued;
474}
475
476/**
477 * hvc_iucv_notifier_add() - HVC notifier for opening a TTY for the first time.
478 * @hp: Pointer to the HVC device (struct hvc_struct)
479 * @id: Additional data (originally passed to hvc_alloc): the index of an struct
480 * hvc_iucv_private instance.
481 *
482 * The function sets the tty state to TTY_OPENED for the struct hvc_iucv_private
483 * instance that is derived from @id. Always returns 0.
484 *
485 * Locking: struct hvc_iucv_private->lock, spin_lock_bh
486 */
487static int hvc_iucv_notifier_add(struct hvc_struct *hp, int id)
488{
489 struct hvc_iucv_private *priv;
490
491 priv = hvc_iucv_get_private(num: id);
492 if (!priv)
493 return 0;
494
495 spin_lock_bh(lock: &priv->lock);
496 priv->tty_state = TTY_OPENED;
497 spin_unlock_bh(lock: &priv->lock);
498
499 return 0;
500}
501
502/**
503 * hvc_iucv_cleanup() - Clean up and reset a z/VM IUCV HVC instance.
504 * @priv: Pointer to the struct hvc_iucv_private instance.
505 */
506static void hvc_iucv_cleanup(struct hvc_iucv_private *priv)
507{
508 destroy_tty_buffer_list(list: &priv->tty_outqueue);
509 destroy_tty_buffer_list(list: &priv->tty_inqueue);
510
511 priv->tty_state = TTY_CLOSED;
512 priv->iucv_state = IUCV_DISCONN;
513
514 priv->sndbuf_len = 0;
515}
516
517/**
518 * tty_outqueue_empty() - Test if the tty outq is empty
519 * @priv: Pointer to struct hvc_iucv_private instance.
520 */
521static inline int tty_outqueue_empty(struct hvc_iucv_private *priv)
522{
523 int rc;
524
525 spin_lock_bh(lock: &priv->lock);
526 rc = list_empty(head: &priv->tty_outqueue);
527 spin_unlock_bh(lock: &priv->lock);
528
529 return rc;
530}
531
532/**
533 * flush_sndbuf_sync() - Flush send buffer and wait for completion
534 * @priv: Pointer to struct hvc_iucv_private instance.
535 *
536 * The routine cancels a pending sndbuf work, calls hvc_iucv_send()
537 * to flush any buffered terminal output data and waits for completion.
538 */
539static void flush_sndbuf_sync(struct hvc_iucv_private *priv)
540{
541 int sync_wait;
542
543 cancel_delayed_work_sync(dwork: &priv->sndbuf_work);
544
545 spin_lock_bh(lock: &priv->lock);
546 hvc_iucv_send(priv); /* force sending buffered data */
547 sync_wait = !list_empty(head: &priv->tty_outqueue); /* anything queued ? */
548 spin_unlock_bh(lock: &priv->lock);
549
550 if (sync_wait)
551 wait_event_timeout(priv->sndbuf_waitq,
552 tty_outqueue_empty(priv), HZ/10);
553}
554
555/**
556 * hvc_iucv_hangup() - Sever IUCV path and schedule hvc tty hang up
557 * @priv: Pointer to hvc_iucv_private structure
558 *
559 * This routine severs an existing IUCV communication path and hangs
560 * up the underlying HVC terminal device.
561 * The hang-up occurs only if an IUCV communication path is established;
562 * otherwise there is no need to hang up the terminal device.
563 *
564 * The IUCV HVC hang-up is separated into two steps:
565 * 1. After the IUCV path has been severed, the iucv_state is set to
566 * IUCV_SEVERED.
567 * 2. Later, when the HVC thread calls hvc_iucv_get_chars(), the
568 * IUCV_SEVERED state causes the tty hang-up in the HVC layer.
569 *
570 * If the tty has not yet been opened, clean up the hvc_iucv_private
571 * structure to allow re-connects.
572 * If the tty has been opened, let get_chars() return -EPIPE to signal
573 * the HVC layer to hang up the tty and, if so, wake up the HVC thread
574 * to call get_chars()...
575 *
576 * Special notes on hanging up a HVC terminal instantiated as console:
577 * Hang-up: 1. do_tty_hangup() replaces file ops (= hung_up_tty_fops)
578 * 2. do_tty_hangup() calls tty->ops->close() for console_filp
579 * => no hangup notifier is called by HVC (default)
580 * 2. hvc_close() returns because of tty_hung_up_p(filp)
581 * => no delete notifier is called!
582 * Finally, the back-end is not being notified, thus, the tty session is
583 * kept active (TTY_OPEN) to be ready for re-connects.
584 *
585 * Locking: spin_lock(&priv->lock) w/o disabling bh
586 */
587static void hvc_iucv_hangup(struct hvc_iucv_private *priv)
588{
589 struct iucv_path *path;
590
591 path = NULL;
592 spin_lock(lock: &priv->lock);
593 if (priv->iucv_state == IUCV_CONNECTED) {
594 path = priv->path;
595 priv->path = NULL;
596 priv->iucv_state = IUCV_SEVERED;
597 if (priv->tty_state == TTY_CLOSED)
598 hvc_iucv_cleanup(priv);
599 else
600 /* console is special (see above) */
601 if (priv->is_console) {
602 hvc_iucv_cleanup(priv);
603 priv->tty_state = TTY_OPENED;
604 } else
605 hvc_kick();
606 }
607 spin_unlock(lock: &priv->lock);
608
609 /* finally sever path (outside of priv->lock due to lock ordering) */
610 if (path) {
611 iucv_path_sever(path, NULL);
612 iucv_path_free(path);
613 }
614}
615
616/**
617 * hvc_iucv_notifier_hangup() - HVC notifier for TTY hangups.
618 * @hp: Pointer to the HVC device (struct hvc_struct)
619 * @id: Additional data (originally passed to hvc_alloc):
620 * the index of an struct hvc_iucv_private instance.
621 *
622 * This routine notifies the HVC back-end that a tty hangup (carrier loss,
623 * virtual or otherwise) has occurred.
624 * The z/VM IUCV HVC device driver ignores virtual hangups (vhangup())
625 * to keep an existing IUCV communication path established.
626 * (Background: vhangup() is called from user space (by getty or login) to
627 * disable writing to the tty by other applications).
628 * If the tty has been opened and an established IUCV path has been severed
629 * (we caused the tty hangup), the function calls hvc_iucv_cleanup().
630 *
631 * Locking: struct hvc_iucv_private->lock
632 */
633static void hvc_iucv_notifier_hangup(struct hvc_struct *hp, int id)
634{
635 struct hvc_iucv_private *priv;
636
637 priv = hvc_iucv_get_private(num: id);
638 if (!priv)
639 return;
640
641 flush_sndbuf_sync(priv);
642
643 spin_lock_bh(lock: &priv->lock);
644 /* NOTE: If the hangup was scheduled by ourself (from the iucv
645 * path_servered callback [IUCV_SEVERED]), we have to clean up
646 * our structure and to set state to TTY_CLOSED.
647 * If the tty was hung up otherwise (e.g. vhangup()), then we
648 * ignore this hangup and keep an established IUCV path open...
649 * (...the reason is that we are not able to connect back to the
650 * client if we disconnect on hang up) */
651 priv->tty_state = TTY_CLOSED;
652
653 if (priv->iucv_state == IUCV_SEVERED)
654 hvc_iucv_cleanup(priv);
655 spin_unlock_bh(lock: &priv->lock);
656}
657
658/**
659 * hvc_iucv_dtr_rts() - HVC notifier for handling DTR/RTS
660 * @hp: Pointer the HVC device (struct hvc_struct)
661 * @active: True to raise or false to lower DTR/RTS lines
662 *
663 * This routine notifies the HVC back-end to raise or lower DTR/RTS
664 * lines. Raising DTR/RTS is ignored. Lowering DTR/RTS indicates to
665 * drop the IUCV connection (similar to hang up the modem).
666 */
667static void hvc_iucv_dtr_rts(struct hvc_struct *hp, bool active)
668{
669 struct hvc_iucv_private *priv;
670 struct iucv_path *path;
671
672 /* Raising the DTR/RTS is ignored as IUCV connections can be
673 * established at any times.
674 */
675 if (active)
676 return;
677
678 priv = hvc_iucv_get_private(num: hp->vtermno);
679 if (!priv)
680 return;
681
682 /* Lowering the DTR/RTS lines disconnects an established IUCV
683 * connection.
684 */
685 flush_sndbuf_sync(priv);
686
687 spin_lock_bh(lock: &priv->lock);
688 path = priv->path; /* save reference to IUCV path */
689 priv->path = NULL;
690 priv->iucv_state = IUCV_DISCONN;
691 spin_unlock_bh(lock: &priv->lock);
692
693 /* Sever IUCV path outside of priv->lock due to lock ordering of:
694 * priv->lock <--> iucv_table_lock */
695 if (path) {
696 iucv_path_sever(path, NULL);
697 iucv_path_free(path);
698 }
699}
700
701/**
702 * hvc_iucv_notifier_del() - HVC notifier for closing a TTY for the last time.
703 * @hp: Pointer to the HVC device (struct hvc_struct)
704 * @id: Additional data (originally passed to hvc_alloc):
705 * the index of an struct hvc_iucv_private instance.
706 *
707 * This routine notifies the HVC back-end that the last tty device fd has been
708 * closed. The function cleans up tty resources. The clean-up of the IUCV
709 * connection is done in hvc_iucv_dtr_rts() and depends on the HUPCL termios
710 * control setting.
711 *
712 * Locking: struct hvc_iucv_private->lock
713 */
714static void hvc_iucv_notifier_del(struct hvc_struct *hp, int id)
715{
716 struct hvc_iucv_private *priv;
717
718 priv = hvc_iucv_get_private(num: id);
719 if (!priv)
720 return;
721
722 flush_sndbuf_sync(priv);
723
724 spin_lock_bh(lock: &priv->lock);
725 destroy_tty_buffer_list(list: &priv->tty_outqueue);
726 destroy_tty_buffer_list(list: &priv->tty_inqueue);
727 priv->tty_state = TTY_CLOSED;
728 priv->sndbuf_len = 0;
729 spin_unlock_bh(lock: &priv->lock);
730}
731
732/**
733 * hvc_iucv_filter_connreq() - Filter connection request based on z/VM user ID
734 * @ipvmid: Originating z/VM user ID (right padded with blanks)
735 *
736 * Returns 0 if the z/VM user ID that is specified with @ipvmid is permitted to
737 * connect, otherwise non-zero.
738 */
739static int hvc_iucv_filter_connreq(u8 ipvmid[8])
740{
741 const char *wildcard, *filter_entry;
742 size_t i, len;
743
744 /* Note: default policy is ACCEPT if no filter is set */
745 if (!hvc_iucv_filter_size)
746 return 0;
747
748 for (i = 0; i < hvc_iucv_filter_size; i++) {
749 filter_entry = hvc_iucv_filter + (8 * i);
750
751 /* If a filter entry contains the filter wildcard character,
752 * reduce the length to match the leading portion of the user
753 * ID only (wildcard match). Characters following the wildcard
754 * are ignored.
755 */
756 wildcard = strnchr(filter_entry, 8, FILTER_WILDCARD_CHAR);
757 len = (wildcard) ? wildcard - filter_entry : 8;
758 if (0 == memcmp(p: ipvmid, q: filter_entry, size: len))
759 return 0;
760 }
761 return 1;
762}
763
764/**
765 * hvc_iucv_path_pending() - IUCV handler to process a connection request.
766 * @path: Pending path (struct iucv_path)
767 * @ipvmid: z/VM system identifier of originator
768 * @ipuser: User specified data for this path
769 * (AF_IUCV: port/service name and originator port)
770 *
771 * The function uses the @ipuser data to determine if the pending path belongs
772 * to a terminal managed by this device driver.
773 * If the path belongs to this driver, ensure that the terminal is not accessed
774 * multiple times (only one connection to a terminal is allowed).
775 * If the terminal is not yet connected, the pending path is accepted and is
776 * associated to the appropriate struct hvc_iucv_private instance.
777 *
778 * Returns 0 if @path belongs to a terminal managed by the this device driver;
779 * otherwise returns -ENODEV in order to dispatch this path to other handlers.
780 *
781 * Locking: struct hvc_iucv_private->lock
782 */
783static int hvc_iucv_path_pending(struct iucv_path *path, u8 *ipvmid,
784 u8 *ipuser)
785{
786 struct hvc_iucv_private *priv, *tmp;
787 u8 wildcard[9] = "lnxhvc ";
788 int i, rc, find_unused;
789 u8 nuser_data[16];
790 u8 vm_user_id[9];
791
792 ASCEBC(wildcard, sizeof(wildcard));
793 find_unused = !memcmp(p: wildcard, q: ipuser, size: 8);
794
795 /* First, check if the pending path request is managed by this
796 * IUCV handler:
797 * - find a disconnected device if ipuser contains the wildcard
798 * - find the device that matches the terminal ID in ipuser
799 */
800 priv = NULL;
801 for (i = 0; i < hvc_iucv_devices; i++) {
802 tmp = hvc_iucv_table[i];
803 if (!tmp)
804 continue;
805
806 if (find_unused) {
807 spin_lock(lock: &tmp->lock);
808 if (tmp->iucv_state == IUCV_DISCONN)
809 priv = tmp;
810 spin_unlock(lock: &tmp->lock);
811
812 } else if (!memcmp(p: tmp->srv_name, q: ipuser, size: 8))
813 priv = tmp;
814 if (priv)
815 break;
816 }
817 if (!priv)
818 return -ENODEV;
819
820 /* Enforce that ipvmid is allowed to connect to us */
821 read_lock(&hvc_iucv_filter_lock);
822 rc = hvc_iucv_filter_connreq(ipvmid);
823 read_unlock(&hvc_iucv_filter_lock);
824 if (rc) {
825 iucv_path_sever(path, userdata: ipuser);
826 iucv_path_free(path);
827 memcpy(vm_user_id, ipvmid, 8);
828 vm_user_id[8] = 0;
829 pr_info("A connection request from z/VM user ID %s "
830 "was refused\n", vm_user_id);
831 return 0;
832 }
833
834 spin_lock(lock: &priv->lock);
835
836 /* If the terminal is already connected or being severed, then sever
837 * this path to enforce that there is only ONE established communication
838 * path per terminal. */
839 if (priv->iucv_state != IUCV_DISCONN) {
840 iucv_path_sever(path, userdata: ipuser);
841 iucv_path_free(path);
842 goto out_path_handled;
843 }
844
845 /* accept path */
846 memcpy(nuser_data, ipuser + 8, 8); /* remote service (for af_iucv) */
847 memcpy(nuser_data + 8, ipuser, 8); /* local service (for af_iucv) */
848 path->msglim = 0xffff; /* IUCV MSGLIMIT */
849 path->flags &= ~IUCV_IPRMDATA; /* TODO: use IUCV_IPRMDATA */
850 rc = iucv_path_accept(path, handler: &hvc_iucv_handler, userdata: nuser_data, private: priv);
851 if (rc) {
852 iucv_path_sever(path, userdata: ipuser);
853 iucv_path_free(path);
854 goto out_path_handled;
855 }
856 priv->path = path;
857 priv->iucv_state = IUCV_CONNECTED;
858
859 /* store path information */
860 memcpy(priv->info_path, ipvmid, 8);
861 memcpy(priv->info_path + 8, ipuser + 8, 8);
862
863 /* flush buffered output data... */
864 schedule_delayed_work(dwork: &priv->sndbuf_work, delay: 5);
865
866out_path_handled:
867 spin_unlock(lock: &priv->lock);
868 return 0;
869}
870
871/**
872 * hvc_iucv_path_severed() - IUCV handler to process a path sever.
873 * @path: Pending path (struct iucv_path)
874 * @ipuser: User specified data for this path
875 * (AF_IUCV: port/service name and originator port)
876 *
877 * This function calls the hvc_iucv_hangup() function for the
878 * respective IUCV HVC terminal.
879 *
880 * Locking: struct hvc_iucv_private->lock
881 */
882static void hvc_iucv_path_severed(struct iucv_path *path, u8 *ipuser)
883{
884 struct hvc_iucv_private *priv = path->private;
885
886 hvc_iucv_hangup(priv);
887}
888
889/**
890 * hvc_iucv_msg_pending() - IUCV handler to process an incoming IUCV message.
891 * @path: Pending path (struct iucv_path)
892 * @msg: Pointer to the IUCV message
893 *
894 * The function puts an incoming message on the input queue for later
895 * processing (by hvc_iucv_get_chars() / hvc_iucv_write()).
896 * If the tty has not yet been opened, the message is rejected.
897 *
898 * Locking: struct hvc_iucv_private->lock
899 */
900static void hvc_iucv_msg_pending(struct iucv_path *path,
901 struct iucv_message *msg)
902{
903 struct hvc_iucv_private *priv = path->private;
904 struct iucv_tty_buffer *rb;
905
906 /* reject messages that exceed max size of iucv_tty_msg->datalen */
907 if (msg->length > MSG_SIZE(MSG_MAX_DATALEN)) {
908 iucv_message_reject(path, msg);
909 return;
910 }
911
912 spin_lock(lock: &priv->lock);
913
914 /* reject messages if tty has not yet been opened */
915 if (priv->tty_state == TTY_CLOSED) {
916 iucv_message_reject(path, msg);
917 goto unlock_return;
918 }
919
920 /* allocate tty buffer to save iucv msg only */
921 rb = alloc_tty_buffer(size: 0, GFP_ATOMIC);
922 if (!rb) {
923 iucv_message_reject(path, msg);
924 goto unlock_return; /* -ENOMEM */
925 }
926 rb->msg = *msg;
927
928 list_add_tail(new: &rb->list, head: &priv->tty_inqueue);
929
930 hvc_kick(); /* wake up hvc thread */
931
932unlock_return:
933 spin_unlock(lock: &priv->lock);
934}
935
936/**
937 * hvc_iucv_msg_complete() - IUCV handler to process message completion
938 * @path: Pending path (struct iucv_path)
939 * @msg: Pointer to the IUCV message
940 *
941 * The function is called upon completion of message delivery to remove the
942 * message from the outqueue. Additional delivery information can be found
943 * msg->audit: rejected messages (0x040000 (IPADRJCT)), and
944 * purged messages (0x010000 (IPADPGNR)).
945 *
946 * Locking: struct hvc_iucv_private->lock
947 */
948static void hvc_iucv_msg_complete(struct iucv_path *path,
949 struct iucv_message *msg)
950{
951 struct hvc_iucv_private *priv = path->private;
952 struct iucv_tty_buffer *ent, *next;
953 LIST_HEAD(list_remove);
954
955 spin_lock(lock: &priv->lock);
956 list_for_each_entry_safe(ent, next, &priv->tty_outqueue, list)
957 if (ent->msg.id == msg->id) {
958 list_move(list: &ent->list, head: &list_remove);
959 break;
960 }
961 wake_up(&priv->sndbuf_waitq);
962 spin_unlock(lock: &priv->lock);
963 destroy_tty_buffer_list(list: &list_remove);
964}
965
966static ssize_t hvc_iucv_dev_termid_show(struct device *dev,
967 struct device_attribute *attr,
968 char *buf)
969{
970 struct hvc_iucv_private *priv = dev_get_drvdata(dev);
971 size_t len;
972
973 len = sizeof(priv->srv_name);
974 memcpy(buf, priv->srv_name, len);
975 EBCASC(buf, len);
976 buf[len++] = '\n';
977 return len;
978}
979
980static ssize_t hvc_iucv_dev_state_show(struct device *dev,
981 struct device_attribute *attr,
982 char *buf)
983{
984 struct hvc_iucv_private *priv = dev_get_drvdata(dev);
985 return sprintf(buf, fmt: "%u:%u\n", priv->iucv_state, priv->tty_state);
986}
987
988static ssize_t hvc_iucv_dev_peer_show(struct device *dev,
989 struct device_attribute *attr,
990 char *buf)
991{
992 struct hvc_iucv_private *priv = dev_get_drvdata(dev);
993 char vmid[9], ipuser[9];
994
995 memset(vmid, 0, sizeof(vmid));
996 memset(ipuser, 0, sizeof(ipuser));
997
998 spin_lock_bh(lock: &priv->lock);
999 if (priv->iucv_state == IUCV_CONNECTED) {
1000 memcpy(vmid, priv->info_path, 8);
1001 memcpy(ipuser, priv->info_path + 8, 8);
1002 }
1003 spin_unlock_bh(lock: &priv->lock);
1004 EBCASC(ipuser, 8);
1005
1006 return sprintf(buf, fmt: "%s:%s\n", vmid, ipuser);
1007}
1008
1009
1010/* HVC operations */
1011static const struct hv_ops hvc_iucv_ops = {
1012 .get_chars = hvc_iucv_get_chars,
1013 .put_chars = hvc_iucv_put_chars,
1014 .notifier_add = hvc_iucv_notifier_add,
1015 .notifier_del = hvc_iucv_notifier_del,
1016 .notifier_hangup = hvc_iucv_notifier_hangup,
1017 .dtr_rts = hvc_iucv_dtr_rts,
1018};
1019
1020/* IUCV HVC device attributes */
1021static DEVICE_ATTR(termid, 0640, hvc_iucv_dev_termid_show, NULL);
1022static DEVICE_ATTR(state, 0640, hvc_iucv_dev_state_show, NULL);
1023static DEVICE_ATTR(peer, 0640, hvc_iucv_dev_peer_show, NULL);
1024static struct attribute *hvc_iucv_dev_attrs[] = {
1025 &dev_attr_termid.attr,
1026 &dev_attr_state.attr,
1027 &dev_attr_peer.attr,
1028 NULL,
1029};
1030static struct attribute_group hvc_iucv_dev_attr_group = {
1031 .attrs = hvc_iucv_dev_attrs,
1032};
1033static const struct attribute_group *hvc_iucv_dev_attr_groups[] = {
1034 &hvc_iucv_dev_attr_group,
1035 NULL,
1036};
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(size: sizeof(struct hvc_iucv_private), GFP_KERNEL);
1055 if (!priv)
1056 return -ENOMEM;
1057
1058 spin_lock_init(&priv->lock);
1059 INIT_LIST_HEAD(list: &priv->tty_outqueue);
1060 INIT_LIST_HEAD(list: &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(objp: 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(vtermno: id, /* PAGE_SIZE */
1075 data: id, ops: &hvc_iucv_ops, outbuf_size: 256);
1076 if (IS_ERR(ptr: priv->hvc)) {
1077 rc = PTR_ERR(ptr: 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(buf: name, size: 9, fmt: "lnxhvc%-2d", id);
1086 memcpy(priv->srv_name, name, 8);
1087 ASCEBC(priv->srv_name, 8);
1088
1089 /* create and setup device */
1090 priv->dev = kzalloc(size: sizeof(*priv->dev), GFP_KERNEL);
1091 if (!priv->dev) {
1092 rc = -ENOMEM;
1093 goto out_error_dev;
1094 }
1095 dev_set_name(dev: priv->dev, name: "hvc_iucv%d", id);
1096 dev_set_drvdata(dev: priv->dev, data: priv);
1097 priv->dev->bus = &iucv_bus;
1098 priv->dev->parent = iucv_root;
1099 priv->dev->groups = hvc_iucv_dev_attr_groups;
1100 priv->dev->release = (void (*)(struct device *)) kfree;
1101 rc = device_register(dev: priv->dev);
1102 if (rc) {
1103 put_device(dev: priv->dev);
1104 goto out_error_dev;
1105 }
1106
1107 hvc_iucv_table[id] = priv;
1108 return 0;
1109
1110out_error_dev:
1111 hvc_remove(hp: priv->hvc);
1112out_error_hvc:
1113 free_page((unsigned long) priv->sndbuf);
1114 kfree(objp: priv);
1115
1116 return rc;
1117}
1118
1119/**
1120 * hvc_iucv_destroy() - Destroy and free hvc_iucv_private instances
1121 */
1122static void __init hvc_iucv_destroy(struct hvc_iucv_private *priv)
1123{
1124 hvc_remove(hp: priv->hvc);
1125 device_unregister(dev: priv->dev);
1126 free_page((unsigned long) priv->sndbuf);
1127 kfree(objp: priv);
1128}
1129
1130/**
1131 * hvc_iucv_parse_filter() - Parse filter for a single z/VM user ID
1132 * @filter: String containing a comma-separated list of z/VM user IDs
1133 * @dest: Location where to store the parsed z/VM user ID
1134 */
1135static const char *hvc_iucv_parse_filter(const char *filter, char *dest)
1136{
1137 const char *nextdelim, *residual;
1138 size_t len;
1139
1140 nextdelim = strchr(filter, ',');
1141 if (nextdelim) {
1142 len = nextdelim - filter;
1143 residual = nextdelim + 1;
1144 } else {
1145 len = strlen(filter);
1146 residual = filter + len;
1147 }
1148
1149 if (len == 0)
1150 return ERR_PTR(error: -EINVAL);
1151
1152 /* check for '\n' (if called from sysfs) */
1153 if (filter[len - 1] == '\n')
1154 len--;
1155
1156 /* prohibit filter entries containing the wildcard character only */
1157 if (len == 1 && *filter == FILTER_WILDCARD_CHAR)
1158 return ERR_PTR(error: -EINVAL);
1159
1160 if (len > 8)
1161 return ERR_PTR(error: -EINVAL);
1162
1163 /* pad with blanks and save upper case version of user ID */
1164 memset(dest, ' ', 8);
1165 while (len--)
1166 dest[len] = toupper(filter[len]);
1167 return residual;
1168}
1169
1170/**
1171 * hvc_iucv_setup_filter() - Set up z/VM user ID filter
1172 * @filter: String consisting of a comma-separated list of z/VM user IDs
1173 *
1174 * The function parses the @filter string and creates an array containing
1175 * the list of z/VM user ID filter entries.
1176 * Return code 0 means success, -EINVAL if the filter is syntactically
1177 * incorrect, -ENOMEM if there was not enough memory to allocate the
1178 * filter list array, or -ENOSPC if too many z/VM user IDs have been specified.
1179 */
1180static int hvc_iucv_setup_filter(const char *val)
1181{
1182 const char *residual;
1183 int err;
1184 size_t size, count;
1185 void *array, *old_filter;
1186
1187 count = strlen(val);
1188 if (count == 0 || (count == 1 && val[0] == '\n')) {
1189 size = 0;
1190 array = NULL;
1191 goto out_replace_filter; /* clear filter */
1192 }
1193
1194 /* count user IDs in order to allocate sufficient memory */
1195 size = 1;
1196 residual = val;
1197 while ((residual = strchr(residual, ',')) != NULL) {
1198 residual++;
1199 size++;
1200 }
1201
1202 /* check if the specified list exceeds the filter limit */
1203 if (size > MAX_VMID_FILTER)
1204 return -ENOSPC;
1205
1206 array = kcalloc(n: size, size: 8, GFP_KERNEL);
1207 if (!array)
1208 return -ENOMEM;
1209
1210 count = size;
1211 residual = val;
1212 while (*residual && count) {
1213 residual = hvc_iucv_parse_filter(filter: residual,
1214 dest: array + ((size - count) * 8));
1215 if (IS_ERR(ptr: residual)) {
1216 err = PTR_ERR(ptr: residual);
1217 kfree(objp: array);
1218 goto out_err;
1219 }
1220 count--;
1221 }
1222
1223out_replace_filter:
1224 write_lock_bh(&hvc_iucv_filter_lock);
1225 old_filter = hvc_iucv_filter;
1226 hvc_iucv_filter_size = size;
1227 hvc_iucv_filter = array;
1228 write_unlock_bh(&hvc_iucv_filter_lock);
1229 kfree(objp: old_filter);
1230
1231 err = 0;
1232out_err:
1233 return err;
1234}
1235
1236/**
1237 * param_set_vmidfilter() - Set z/VM user ID filter parameter
1238 * @val: String consisting of a comma-separated list of z/VM user IDs
1239 * @kp: Kernel parameter pointing to hvc_iucv_filter array
1240 *
1241 * The function sets up the z/VM user ID filter specified as comma-separated
1242 * list of user IDs in @val.
1243 * Note: If it is called early in the boot process, @val is stored and
1244 * parsed later in hvc_iucv_init().
1245 */
1246static int param_set_vmidfilter(const char *val, const struct kernel_param *kp)
1247{
1248 int rc;
1249
1250 if (!MACHINE_IS_VM || !hvc_iucv_devices)
1251 return -ENODEV;
1252
1253 if (!val)
1254 return -EINVAL;
1255
1256 rc = 0;
1257 if (slab_is_available())
1258 rc = hvc_iucv_setup_filter(val);
1259 else
1260 hvc_iucv_filter_string = val; /* defer... */
1261 return rc;
1262}
1263
1264/**
1265 * param_get_vmidfilter() - Get z/VM user ID filter
1266 * @buffer: Buffer to store z/VM user ID filter,
1267 * (buffer size assumption PAGE_SIZE)
1268 * @kp: Kernel parameter pointing to the hvc_iucv_filter array
1269 *
1270 * The function stores the filter as a comma-separated list of z/VM user IDs
1271 * in @buffer. Typically, sysfs routines call this function for attr show.
1272 */
1273static int param_get_vmidfilter(char *buffer, const struct kernel_param *kp)
1274{
1275 int rc;
1276 size_t index, len;
1277 void *start, *end;
1278
1279 if (!MACHINE_IS_VM || !hvc_iucv_devices)
1280 return -ENODEV;
1281
1282 rc = 0;
1283 read_lock_bh(&hvc_iucv_filter_lock);
1284 for (index = 0; index < hvc_iucv_filter_size; index++) {
1285 start = hvc_iucv_filter + (8 * index);
1286 end = memchr(p: start, c: ' ', size: 8);
1287 len = (end) ? end - start : 8;
1288 memcpy(buffer + rc, start, len);
1289 rc += len;
1290 buffer[rc++] = ',';
1291 }
1292 read_unlock_bh(&hvc_iucv_filter_lock);
1293 if (rc)
1294 buffer[--rc] = '\0'; /* replace last comma and update rc */
1295 return rc;
1296}
1297
1298#define param_check_vmidfilter(name, p) __param_check(name, p, void)
1299
1300static const struct kernel_param_ops param_ops_vmidfilter = {
1301 .set = param_set_vmidfilter,
1302 .get = param_get_vmidfilter,
1303};
1304
1305/**
1306 * hvc_iucv_init() - z/VM IUCV HVC device driver initialization
1307 */
1308static int __init hvc_iucv_init(void)
1309{
1310 int rc;
1311 unsigned int i;
1312
1313 if (!hvc_iucv_devices)
1314 return -ENODEV;
1315
1316 if (!MACHINE_IS_VM) {
1317 pr_notice("The z/VM IUCV HVC device driver cannot "
1318 "be used without z/VM\n");
1319 rc = -ENODEV;
1320 goto out_error;
1321 }
1322
1323 if (hvc_iucv_devices > MAX_HVC_IUCV_LINES) {
1324 pr_err("%lu is not a valid value for the hvc_iucv= "
1325 "kernel parameter\n", hvc_iucv_devices);
1326 rc = -EINVAL;
1327 goto out_error;
1328 }
1329
1330 /* parse hvc_iucv_allow string and create z/VM user ID filter list */
1331 if (hvc_iucv_filter_string) {
1332 rc = hvc_iucv_setup_filter(val: hvc_iucv_filter_string);
1333 switch (rc) {
1334 case 0:
1335 break;
1336 case -ENOMEM:
1337 pr_err("Allocating memory failed with "
1338 "reason code=%d\n", 3);
1339 goto out_error;
1340 case -EINVAL:
1341 pr_err("hvc_iucv_allow= does not specify a valid "
1342 "z/VM user ID list\n");
1343 goto out_error;
1344 case -ENOSPC:
1345 pr_err("hvc_iucv_allow= specifies too many "
1346 "z/VM user IDs\n");
1347 goto out_error;
1348 default:
1349 goto out_error;
1350 }
1351 }
1352
1353 hvc_iucv_buffer_cache = kmem_cache_create(KMSG_COMPONENT,
1354 size: sizeof(struct iucv_tty_buffer),
1355 align: 0, flags: 0, NULL);
1356 if (!hvc_iucv_buffer_cache) {
1357 pr_err("Allocating memory failed with reason code=%d\n", 1);
1358 rc = -ENOMEM;
1359 goto out_error;
1360 }
1361
1362 hvc_iucv_mempool = mempool_create_slab_pool(MEMPOOL_MIN_NR,
1363 kc: hvc_iucv_buffer_cache);
1364 if (!hvc_iucv_mempool) {
1365 pr_err("Allocating memory failed with reason code=%d\n", 2);
1366 kmem_cache_destroy(s: hvc_iucv_buffer_cache);
1367 rc = -ENOMEM;
1368 goto out_error;
1369 }
1370
1371 /* register the first terminal device as console
1372 * (must be done before allocating hvc terminal devices) */
1373 rc = hvc_instantiate(vtermno: 0, IUCV_HVC_CON_IDX, ops: &hvc_iucv_ops);
1374 if (rc) {
1375 pr_err("Registering HVC terminal device as "
1376 "Linux console failed\n");
1377 goto out_error_memory;
1378 }
1379
1380 /* allocate hvc_iucv_private structs */
1381 for (i = 0; i < hvc_iucv_devices; i++) {
1382 rc = hvc_iucv_alloc(id: i, is_console: (i == IUCV_HVC_CON_IDX) ? 1 : 0);
1383 if (rc) {
1384 pr_err("Creating a new HVC terminal device "
1385 "failed with error code=%d\n", rc);
1386 goto out_error_hvc;
1387 }
1388 }
1389
1390 /* register IUCV callback handler */
1391 rc = iucv_register(handler: &hvc_iucv_handler, smp: 0);
1392 if (rc) {
1393 pr_err("Registering IUCV handlers failed with error code=%d\n",
1394 rc);
1395 goto out_error_hvc;
1396 }
1397
1398 return 0;
1399
1400out_error_hvc:
1401 for (i = 0; i < hvc_iucv_devices; i++)
1402 if (hvc_iucv_table[i])
1403 hvc_iucv_destroy(priv: hvc_iucv_table[i]);
1404out_error_memory:
1405 mempool_destroy(pool: hvc_iucv_mempool);
1406 kmem_cache_destroy(s: hvc_iucv_buffer_cache);
1407out_error:
1408 kfree(objp: hvc_iucv_filter);
1409 hvc_iucv_devices = 0; /* ensure that we do not provide any device */
1410 return rc;
1411}
1412
1413/**
1414 * hvc_iucv_config() - Parsing of hvc_iucv= kernel command line parameter
1415 * @val: Parameter value (numeric)
1416 */
1417static int __init hvc_iucv_config(char *val)
1418{
1419 if (kstrtoul(s: val, base: 10, res: &hvc_iucv_devices))
1420 pr_warn("hvc_iucv= invalid parameter value '%s'\n", val);
1421 return 1;
1422}
1423
1424
1425device_initcall(hvc_iucv_init);
1426__setup("hvc_iucv=", hvc_iucv_config);
1427core_param(hvc_iucv_allow, hvc_iucv_filter, vmidfilter, 0640);
1428

source code of linux/drivers/tty/hvc/hvc_iucv.c