GNU Linux-libre 4.9.337-gnu1
[releases.git] / drivers / tty / hvc / hvc_iucv.c
1 /*
2  * z/VM IUCV hypervisor console (HVC) device driver
3  *
4  * This HVC device driver provides terminal access using
5  * z/VM IUCV communication paths.
6  *
7  * Copyright IBM Corp. 2008, 2013
8  *
9  * Author(s):   Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
10  */
11 #define KMSG_COMPONENT          "hvc_iucv"
12 #define pr_fmt(fmt)             KMSG_COMPONENT ": " fmt
13
14 #include <linux/types.h>
15 #include <linux/slab.h>
16 #include <asm/ebcdic.h>
17 #include <linux/ctype.h>
18 #include <linux/delay.h>
19 #include <linux/device.h>
20 #include <linux/init.h>
21 #include <linux/mempool.h>
22 #include <linux/moduleparam.h>
23 #include <linux/tty.h>
24 #include <linux/wait.h>
25 #include <net/iucv/iucv.h>
26
27 #include "hvc_console.h"
28
29
30 /* General device driver settings */
31 #define HVC_IUCV_MAGIC          0xc9e4c3e5
32 #define MAX_HVC_IUCV_LINES      HVC_ALLOC_TTY_ADAPTERS
33 #define MEMPOOL_MIN_NR          (PAGE_SIZE / sizeof(struct iucv_tty_buffer)/4)
34
35 /* IUCV TTY message  */
36 #define MSG_VERSION             0x02    /* Message version */
37 #define MSG_TYPE_ERROR          0x01    /* Error message */
38 #define MSG_TYPE_TERMENV        0x02    /* Terminal environment variable */
39 #define MSG_TYPE_TERMIOS        0x04    /* Terminal IO struct update */
40 #define MSG_TYPE_WINSIZE        0x08    /* Terminal window size update */
41 #define MSG_TYPE_DATA           0x10    /* Terminal data */
42
43 struct iucv_tty_msg {
44         u8      version;                /* Message version */
45         u8      type;                   /* Message type */
46 #define MSG_MAX_DATALEN         ((u16)(~0))
47         u16     datalen;                /* Payload length */
48         u8      data[];                 /* Payload buffer */
49 } __attribute__((packed));
50 #define MSG_SIZE(s)             ((s) + offsetof(struct iucv_tty_msg, data))
51
52 enum iucv_state_t {
53         IUCV_DISCONN    = 0,
54         IUCV_CONNECTED  = 1,
55         IUCV_SEVERED    = 2,
56 };
57
58 enum tty_state_t {
59         TTY_CLOSED      = 0,
60         TTY_OPENED      = 1,
61 };
62
63 struct hvc_iucv_private {
64         struct hvc_struct       *hvc;           /* HVC struct reference */
65         u8                      srv_name[8];    /* IUCV service name (ebcdic) */
66         unsigned char           is_console;     /* Linux console usage flag */
67         enum iucv_state_t       iucv_state;     /* IUCV connection status */
68         enum tty_state_t        tty_state;      /* TTY status */
69         struct iucv_path        *path;          /* IUCV path pointer */
70         spinlock_t              lock;           /* hvc_iucv_private lock */
71 #define SNDBUF_SIZE             (PAGE_SIZE)     /* must be < MSG_MAX_DATALEN */
72         void                    *sndbuf;        /* send buffer            */
73         size_t                  sndbuf_len;     /* length of send buffer  */
74 #define QUEUE_SNDBUF_DELAY      (HZ / 25)
75         struct delayed_work     sndbuf_work;    /* work: send iucv msg(s) */
76         wait_queue_head_t       sndbuf_waitq;   /* wait for send completion */
77         struct list_head        tty_outqueue;   /* outgoing IUCV messages */
78         struct list_head        tty_inqueue;    /* incoming IUCV messages */
79         struct device           *dev;           /* device structure */
80         u8                      info_path[16];  /* IUCV path info (dev attr) */
81 };
82
83 struct iucv_tty_buffer {
84         struct list_head        list;   /* list pointer */
85         struct iucv_message     msg;    /* store an IUCV message */
86         size_t                  offset; /* data buffer offset */
87         struct iucv_tty_msg     *mbuf;  /* buffer to store input/output data */
88 };
89
90 /* IUCV callback handler */
91 static  int hvc_iucv_path_pending(struct iucv_path *, u8 *, u8 *);
92 static void hvc_iucv_path_severed(struct iucv_path *, u8 *);
93 static void hvc_iucv_msg_pending(struct iucv_path *, struct iucv_message *);
94 static void hvc_iucv_msg_complete(struct iucv_path *, struct iucv_message *);
95
96
97 /* Kernel module parameter: use one terminal device as default */
98 static unsigned long hvc_iucv_devices = 1;
99
100 /* Array of allocated hvc iucv tty lines... */
101 static struct hvc_iucv_private *hvc_iucv_table[MAX_HVC_IUCV_LINES];
102 #define IUCV_HVC_CON_IDX        (0)
103 /* List of z/VM user ID filter entries (struct iucv_vmid_filter) */
104 #define MAX_VMID_FILTER         (500)
105 #define FILTER_WILDCARD_CHAR    '*'
106 static size_t hvc_iucv_filter_size;
107 static void *hvc_iucv_filter;
108 static const char *hvc_iucv_filter_string;
109 static DEFINE_RWLOCK(hvc_iucv_filter_lock);
110
111 /* Kmem cache and mempool for iucv_tty_buffer elements */
112 static struct kmem_cache *hvc_iucv_buffer_cache;
113 static mempool_t *hvc_iucv_mempool;
114
115 /* IUCV handler callback functions */
116 static struct iucv_handler hvc_iucv_handler = {
117         .path_pending  = hvc_iucv_path_pending,
118         .path_severed  = hvc_iucv_path_severed,
119         .message_complete = hvc_iucv_msg_complete,
120         .message_pending  = hvc_iucv_msg_pending,
121 };
122
123
124 /**
125  * hvc_iucv_get_private() - Return a struct hvc_iucv_private instance.
126  * @num:        The HVC virtual terminal number (vtermno)
127  *
128  * This function returns the struct hvc_iucv_private instance that corresponds
129  * to the HVC virtual terminal number specified as parameter @num.
130  */
131 static struct hvc_iucv_private *hvc_iucv_get_private(uint32_t num)
132 {
133         if ((num < HVC_IUCV_MAGIC) || (num - HVC_IUCV_MAGIC > hvc_iucv_devices))
134                 return NULL;
135         return hvc_iucv_table[num - HVC_IUCV_MAGIC];
136 }
137
138 /**
139  * alloc_tty_buffer() - Return a new struct iucv_tty_buffer element.
140  * @size:       Size of the internal buffer used to store data.
141  * @flags:      Memory allocation flags passed to mempool.
142  *
143  * This function allocates a new struct iucv_tty_buffer element and, optionally,
144  * allocates an internal data buffer with the specified size @size.
145  * The internal data buffer is always allocated with GFP_DMA which is
146  * required for receiving and sending data with IUCV.
147  * Note: The total message size arises from the internal buffer size and the
148  *       members of the iucv_tty_msg structure.
149  * The function returns NULL if memory allocation has failed.
150  */
151 static struct iucv_tty_buffer *alloc_tty_buffer(size_t size, gfp_t flags)
152 {
153         struct iucv_tty_buffer *bufp;
154
155         bufp = mempool_alloc(hvc_iucv_mempool, flags);
156         if (!bufp)
157                 return NULL;
158         memset(bufp, 0, sizeof(*bufp));
159
160         if (size > 0) {
161                 bufp->msg.length = MSG_SIZE(size);
162                 bufp->mbuf = kmalloc(bufp->msg.length, flags | GFP_DMA);
163                 if (!bufp->mbuf) {
164                         mempool_free(bufp, hvc_iucv_mempool);
165                         return NULL;
166                 }
167                 bufp->mbuf->version = MSG_VERSION;
168                 bufp->mbuf->type    = MSG_TYPE_DATA;
169                 bufp->mbuf->datalen = (u16) size;
170         }
171         return bufp;
172 }
173
174 /**
175  * destroy_tty_buffer() - destroy struct iucv_tty_buffer element.
176  * @bufp:       Pointer to a struct iucv_tty_buffer element, SHALL NOT be NULL.
177  */
178 static void destroy_tty_buffer(struct iucv_tty_buffer *bufp)
179 {
180         kfree(bufp->mbuf);
181         mempool_free(bufp, hvc_iucv_mempool);
182 }
183
184 /**
185  * destroy_tty_buffer_list() - call destroy_tty_buffer() for each list element.
186  * @list:       List containing struct iucv_tty_buffer elements.
187  */
188 static void destroy_tty_buffer_list(struct list_head *list)
189 {
190         struct iucv_tty_buffer *ent, *next;
191
192         list_for_each_entry_safe(ent, next, list, list) {
193                 list_del(&ent->list);
194                 destroy_tty_buffer(ent);
195         }
196 }
197
198 /**
199  * hvc_iucv_write() - Receive IUCV message & write data to HVC buffer.
200  * @priv:               Pointer to struct hvc_iucv_private
201  * @buf:                HVC buffer for writing received terminal data.
202  * @count:              HVC buffer size.
203  * @has_more_data:      Pointer to an int variable.
204  *
205  * The function picks up pending messages from the input queue and receives
206  * the message data that is then written to the specified buffer @buf.
207  * If the buffer size @count is less than the data message size, the
208  * message is kept on the input queue and @has_more_data is set to 1.
209  * If all message data has been written, the message is removed from
210  * the input queue.
211  *
212  * The function returns the number of bytes written to the terminal, zero if
213  * there are no pending data messages available or if there is no established
214  * IUCV path.
215  * If the IUCV path has been severed, then -EPIPE is returned to cause a
216  * hang up (that is issued by the HVC layer).
217  */
218 static int hvc_iucv_write(struct hvc_iucv_private *priv,
219                           char *buf, int count, int *has_more_data)
220 {
221         struct iucv_tty_buffer *rb;
222         int written;
223         int rc;
224
225         /* immediately return if there is no IUCV connection */
226         if (priv->iucv_state == IUCV_DISCONN)
227                 return 0;
228
229         /* if the IUCV path has been severed, return -EPIPE to inform the
230          * HVC layer to hang up the tty device. */
231         if (priv->iucv_state == IUCV_SEVERED)
232                 return -EPIPE;
233
234         /* check if there are pending messages */
235         if (list_empty(&priv->tty_inqueue))
236                 return 0;
237
238         /* receive an iucv message and flip data to the tty (ldisc) */
239         rb = list_first_entry(&priv->tty_inqueue, struct iucv_tty_buffer, list);
240
241         written = 0;
242         if (!rb->mbuf) { /* message not yet received ... */
243                 /* allocate mem to store msg data; if no memory is available
244                  * then leave the buffer on the list and re-try later */
245                 rb->mbuf = kmalloc(rb->msg.length, GFP_ATOMIC | GFP_DMA);
246                 if (!rb->mbuf)
247                         return -ENOMEM;
248
249                 rc = __iucv_message_receive(priv->path, &rb->msg, 0,
250                                             rb->mbuf, rb->msg.length, NULL);
251                 switch (rc) {
252                 case 0: /* Successful       */
253                         break;
254                 case 2: /* No message found */
255                 case 9: /* Message purged   */
256                         break;
257                 default:
258                         written = -EIO;
259                 }
260                 /* remove buffer if an error has occurred or received data
261                  * is not correct */
262                 if (rc || (rb->mbuf->version != MSG_VERSION) ||
263                           (rb->msg.length    != MSG_SIZE(rb->mbuf->datalen)))
264                         goto out_remove_buffer;
265         }
266
267         switch (rb->mbuf->type) {
268         case MSG_TYPE_DATA:
269                 written = min_t(int, rb->mbuf->datalen - rb->offset, count);
270                 memcpy(buf, rb->mbuf->data + rb->offset, written);
271                 if (written < (rb->mbuf->datalen - rb->offset)) {
272                         rb->offset += written;
273                         *has_more_data = 1;
274                         goto out_written;
275                 }
276                 break;
277
278         case MSG_TYPE_WINSIZE:
279                 if (rb->mbuf->datalen != sizeof(struct winsize))
280                         break;
281                 /* The caller must ensure that the hvc is locked, which
282                  * is the case when called from hvc_iucv_get_chars() */
283                 __hvc_resize(priv->hvc, *((struct winsize *) rb->mbuf->data));
284                 break;
285
286         case MSG_TYPE_ERROR:    /* ignored ... */
287         case MSG_TYPE_TERMENV:  /* ignored ... */
288         case MSG_TYPE_TERMIOS:  /* ignored ... */
289                 break;
290         }
291
292 out_remove_buffer:
293         list_del(&rb->list);
294         destroy_tty_buffer(rb);
295         *has_more_data = !list_empty(&priv->tty_inqueue);
296
297 out_written:
298         return written;
299 }
300
301 /**
302  * hvc_iucv_get_chars() - HVC get_chars operation.
303  * @vtermno:    HVC virtual terminal number.
304  * @buf:        Pointer to a buffer to store data
305  * @count:      Size of buffer available for writing
306  *
307  * The HVC thread calls this method to read characters from the back-end.
308  * If an IUCV communication path has been established, pending IUCV messages
309  * are received and data is copied into buffer @buf up to @count bytes.
310  *
311  * Locking:     The routine gets called under an irqsave() spinlock; and
312  *              the routine locks the struct hvc_iucv_private->lock to call
313  *              helper functions.
314  */
315 static int hvc_iucv_get_chars(uint32_t vtermno, char *buf, int count)
316 {
317         struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
318         int written;
319         int has_more_data;
320
321         if (count <= 0)
322                 return 0;
323
324         if (!priv)
325                 return -ENODEV;
326
327         spin_lock(&priv->lock);
328         has_more_data = 0;
329         written = hvc_iucv_write(priv, buf, count, &has_more_data);
330         spin_unlock(&priv->lock);
331
332         /* if there are still messages on the queue... schedule another run */
333         if (has_more_data)
334                 hvc_kick();
335
336         return written;
337 }
338
339 /**
340  * hvc_iucv_queue() - Buffer terminal data for sending.
341  * @priv:       Pointer to struct hvc_iucv_private instance.
342  * @buf:        Buffer containing data to send.
343  * @count:      Size of buffer and amount of data to send.
344  *
345  * The function queues data for sending. To actually send the buffered data,
346  * a work queue function is scheduled (with QUEUE_SNDBUF_DELAY).
347  * The function returns the number of data bytes that has been buffered.
348  *
349  * If the device is not connected, data is ignored and the function returns
350  * @count.
351  * If the buffer is full, the function returns 0.
352  * If an existing IUCV communicaton path has been severed, -EPIPE is returned
353  * (that can be passed to HVC layer to cause a tty hangup).
354  */
355 static int hvc_iucv_queue(struct hvc_iucv_private *priv, const char *buf,
356                           int count)
357 {
358         size_t len;
359
360         if (priv->iucv_state == IUCV_DISCONN)
361                 return count;                   /* ignore data */
362
363         if (priv->iucv_state == IUCV_SEVERED)
364                 return -EPIPE;
365
366         len = min_t(size_t, count, SNDBUF_SIZE - priv->sndbuf_len);
367         if (!len)
368                 return 0;
369
370         memcpy(priv->sndbuf + priv->sndbuf_len, buf, len);
371         priv->sndbuf_len += len;
372
373         if (priv->iucv_state == IUCV_CONNECTED)
374                 schedule_delayed_work(&priv->sndbuf_work, QUEUE_SNDBUF_DELAY);
375
376         return len;
377 }
378
379 /**
380  * hvc_iucv_send() - Send an IUCV message containing terminal data.
381  * @priv:       Pointer to struct hvc_iucv_private instance.
382  *
383  * If an IUCV communication path has been established, the buffered output data
384  * is sent via an IUCV message and the number of bytes sent is returned.
385  * Returns 0 if there is no established IUCV communication path or
386  * -EPIPE if an existing IUCV communicaton path has been severed.
387  */
388 static int hvc_iucv_send(struct hvc_iucv_private *priv)
389 {
390         struct iucv_tty_buffer *sb;
391         int rc, len;
392
393         if (priv->iucv_state == IUCV_SEVERED)
394                 return -EPIPE;
395
396         if (priv->iucv_state == IUCV_DISCONN)
397                 return -EIO;
398
399         if (!priv->sndbuf_len)
400                 return 0;
401
402         /* allocate internal buffer to store msg data and also compute total
403          * message length */
404         sb = alloc_tty_buffer(priv->sndbuf_len, GFP_ATOMIC);
405         if (!sb)
406                 return -ENOMEM;
407
408         memcpy(sb->mbuf->data, priv->sndbuf, priv->sndbuf_len);
409         sb->mbuf->datalen = (u16) priv->sndbuf_len;
410         sb->msg.length = MSG_SIZE(sb->mbuf->datalen);
411
412         list_add_tail(&sb->list, &priv->tty_outqueue);
413
414         rc = __iucv_message_send(priv->path, &sb->msg, 0, 0,
415                                  (void *) sb->mbuf, sb->msg.length);
416         if (rc) {
417                 /* drop the message here; however we might want to handle
418                  * 0x03 (msg limit reached) by trying again... */
419                 list_del(&sb->list);
420                 destroy_tty_buffer(sb);
421         }
422         len = priv->sndbuf_len;
423         priv->sndbuf_len = 0;
424
425         return len;
426 }
427
428 /**
429  * hvc_iucv_sndbuf_work() - Send buffered data over IUCV
430  * @work:       Work structure.
431  *
432  * This work queue function sends buffered output data over IUCV and,
433  * if not all buffered data could be sent, reschedules itself.
434  */
435 static void hvc_iucv_sndbuf_work(struct work_struct *work)
436 {
437         struct hvc_iucv_private *priv;
438
439         priv = container_of(work, struct hvc_iucv_private, sndbuf_work.work);
440         if (!priv)
441                 return;
442
443         spin_lock_bh(&priv->lock);
444         hvc_iucv_send(priv);
445         spin_unlock_bh(&priv->lock);
446 }
447
448 /**
449  * hvc_iucv_put_chars() - HVC put_chars operation.
450  * @vtermno:    HVC virtual terminal number.
451  * @buf:        Pointer to an buffer to read data from
452  * @count:      Size of buffer available for reading
453  *
454  * The HVC thread calls this method to write characters to the back-end.
455  * The function calls hvc_iucv_queue() to queue terminal data for sending.
456  *
457  * Locking:     The method gets called under an irqsave() spinlock; and
458  *              locks struct hvc_iucv_private->lock.
459  */
460 static int hvc_iucv_put_chars(uint32_t vtermno, const char *buf, int count)
461 {
462         struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
463         int queued;
464
465         if (count <= 0)
466                 return 0;
467
468         if (!priv)
469                 return -ENODEV;
470
471         spin_lock(&priv->lock);
472         queued = hvc_iucv_queue(priv, buf, count);
473         spin_unlock(&priv->lock);
474
475         return queued;
476 }
477
478 /**
479  * hvc_iucv_notifier_add() - HVC notifier for opening a TTY for the first time.
480  * @hp: Pointer to the HVC device (struct hvc_struct)
481  * @id: Additional data (originally passed to hvc_alloc): the index of an struct
482  *      hvc_iucv_private instance.
483  *
484  * The function sets the tty state to TTY_OPENED for the struct hvc_iucv_private
485  * instance that is derived from @id. Always returns 0.
486  *
487  * Locking:     struct hvc_iucv_private->lock, spin_lock_bh
488  */
489 static int hvc_iucv_notifier_add(struct hvc_struct *hp, int id)
490 {
491         struct hvc_iucv_private *priv;
492
493         priv = hvc_iucv_get_private(id);
494         if (!priv)
495                 return 0;
496
497         spin_lock_bh(&priv->lock);
498         priv->tty_state = TTY_OPENED;
499         spin_unlock_bh(&priv->lock);
500
501         return 0;
502 }
503
504 /**
505  * hvc_iucv_cleanup() - Clean up and reset a z/VM IUCV HVC instance.
506  * @priv:       Pointer to the struct hvc_iucv_private instance.
507  */
508 static void hvc_iucv_cleanup(struct hvc_iucv_private *priv)
509 {
510         destroy_tty_buffer_list(&priv->tty_outqueue);
511         destroy_tty_buffer_list(&priv->tty_inqueue);
512
513         priv->tty_state = TTY_CLOSED;
514         priv->iucv_state = IUCV_DISCONN;
515
516         priv->sndbuf_len = 0;
517 }
518
519 /**
520  * tty_outqueue_empty() - Test if the tty outq is empty
521  * @priv:       Pointer to struct hvc_iucv_private instance.
522  */
523 static inline int tty_outqueue_empty(struct hvc_iucv_private *priv)
524 {
525         int rc;
526
527         spin_lock_bh(&priv->lock);
528         rc = list_empty(&priv->tty_outqueue);
529         spin_unlock_bh(&priv->lock);
530
531         return rc;
532 }
533
534 /**
535  * flush_sndbuf_sync() - Flush send buffer and wait for completion
536  * @priv:       Pointer to struct hvc_iucv_private instance.
537  *
538  * The routine cancels a pending sndbuf work, calls hvc_iucv_send()
539  * to flush any buffered terminal output data and waits for completion.
540  */
541 static void flush_sndbuf_sync(struct hvc_iucv_private *priv)
542 {
543         int sync_wait;
544
545         cancel_delayed_work_sync(&priv->sndbuf_work);
546
547         spin_lock_bh(&priv->lock);
548         hvc_iucv_send(priv);            /* force sending buffered data */
549         sync_wait = !list_empty(&priv->tty_outqueue); /* anything queued ? */
550         spin_unlock_bh(&priv->lock);
551
552         if (sync_wait)
553                 wait_event_timeout(priv->sndbuf_waitq,
554                                    tty_outqueue_empty(priv), HZ/10);
555 }
556
557 /**
558  * hvc_iucv_hangup() - Sever IUCV path and schedule hvc tty hang up
559  * @priv:       Pointer to hvc_iucv_private structure
560  *
561  * This routine severs an existing IUCV communication path and hangs
562  * up the underlying HVC terminal device.
563  * The hang-up occurs only if an IUCV communication path is established;
564  * otherwise there is no need to hang up the terminal device.
565  *
566  * The IUCV HVC hang-up is separated into two steps:
567  * 1. After the IUCV path has been severed, the iucv_state is set to
568  *    IUCV_SEVERED.
569  * 2. Later, when the HVC thread calls hvc_iucv_get_chars(), the
570  *    IUCV_SEVERED state causes the tty hang-up in the HVC layer.
571  *
572  * If the tty has not yet been opened, clean up the hvc_iucv_private
573  * structure to allow re-connects.
574  * If the tty has been opened, let get_chars() return -EPIPE to signal
575  * the HVC layer to hang up the tty and, if so, wake up the HVC thread
576  * to call get_chars()...
577  *
578  * Special notes on hanging up a HVC terminal instantiated as console:
579  * Hang-up:     1. do_tty_hangup() replaces file ops (= hung_up_tty_fops)
580  *              2. do_tty_hangup() calls tty->ops->close() for console_filp
581  *                      => no hangup notifier is called by HVC (default)
582  *              2. hvc_close() returns because of tty_hung_up_p(filp)
583  *                      => no delete notifier is called!
584  * Finally, the back-end is not being notified, thus, the tty session is
585  * kept active (TTY_OPEN) to be ready for re-connects.
586  *
587  * Locking:     spin_lock(&priv->lock) w/o disabling bh
588  */
589 static void hvc_iucv_hangup(struct hvc_iucv_private *priv)
590 {
591         struct iucv_path *path;
592
593         path = NULL;
594         spin_lock(&priv->lock);
595         if (priv->iucv_state == IUCV_CONNECTED) {
596                 path = priv->path;
597                 priv->path = NULL;
598                 priv->iucv_state = IUCV_SEVERED;
599                 if (priv->tty_state == TTY_CLOSED)
600                         hvc_iucv_cleanup(priv);
601                 else
602                         /* console is special (see above) */
603                         if (priv->is_console) {
604                                 hvc_iucv_cleanup(priv);
605                                 priv->tty_state = TTY_OPENED;
606                         } else
607                                 hvc_kick();
608         }
609         spin_unlock(&priv->lock);
610
611         /* finally sever path (outside of priv->lock due to lock ordering) */
612         if (path) {
613                 iucv_path_sever(path, NULL);
614                 iucv_path_free(path);
615         }
616 }
617
618 /**
619  * hvc_iucv_notifier_hangup() - HVC notifier for TTY hangups.
620  * @hp:         Pointer to the HVC device (struct hvc_struct)
621  * @id:         Additional data (originally passed to hvc_alloc):
622  *              the index of an struct hvc_iucv_private instance.
623  *
624  * This routine notifies the HVC back-end that a tty hangup (carrier loss,
625  * virtual or otherwise) has occurred.
626  * The z/VM IUCV HVC device driver ignores virtual hangups (vhangup())
627  * to keep an existing IUCV communication path established.
628  * (Background: vhangup() is called from user space (by getty or login) to
629  *              disable writing to the tty by other applications).
630  * If the tty has been opened and an established IUCV path has been severed
631  * (we caused the tty hangup), the function calls hvc_iucv_cleanup().
632  *
633  * Locking:     struct hvc_iucv_private->lock
634  */
635 static void hvc_iucv_notifier_hangup(struct hvc_struct *hp, int id)
636 {
637         struct hvc_iucv_private *priv;
638
639         priv = hvc_iucv_get_private(id);
640         if (!priv)
641                 return;
642
643         flush_sndbuf_sync(priv);
644
645         spin_lock_bh(&priv->lock);
646         /* NOTE: If the hangup was scheduled by ourself (from the iucv
647          *       path_servered callback [IUCV_SEVERED]), we have to clean up
648          *       our structure and to set state to TTY_CLOSED.
649          *       If the tty was hung up otherwise (e.g. vhangup()), then we
650          *       ignore this hangup and keep an established IUCV path open...
651          *       (...the reason is that we are not able to connect back to the
652          *       client if we disconnect on hang up) */
653         priv->tty_state = TTY_CLOSED;
654
655         if (priv->iucv_state == IUCV_SEVERED)
656                 hvc_iucv_cleanup(priv);
657         spin_unlock_bh(&priv->lock);
658 }
659
660 /**
661  * hvc_iucv_dtr_rts() - HVC notifier for handling DTR/RTS
662  * @hp:         Pointer the HVC device (struct hvc_struct)
663  * @raise:      Non-zero to raise or zero to lower DTR/RTS lines
664  *
665  * This routine notifies the HVC back-end to raise or lower DTR/RTS
666  * lines.  Raising DTR/RTS is ignored.  Lowering DTR/RTS indicates to
667  * drop the IUCV connection (similar to hang up the modem).
668  */
669 static void hvc_iucv_dtr_rts(struct hvc_struct *hp, int raise)
670 {
671         struct hvc_iucv_private *priv;
672         struct iucv_path        *path;
673
674         /* Raising the DTR/RTS is ignored as IUCV connections can be
675          * established at any times.
676          */
677         if (raise)
678                 return;
679
680         priv = hvc_iucv_get_private(hp->vtermno);
681         if (!priv)
682                 return;
683
684         /* Lowering the DTR/RTS lines disconnects an established IUCV
685          * connection.
686          */
687         flush_sndbuf_sync(priv);
688
689         spin_lock_bh(&priv->lock);
690         path = priv->path;              /* save reference to IUCV path */
691         priv->path = NULL;
692         priv->iucv_state = IUCV_DISCONN;
693         spin_unlock_bh(&priv->lock);
694
695         /* Sever IUCV path outside of priv->lock due to lock ordering of:
696          * priv->lock <--> iucv_table_lock */
697         if (path) {
698                 iucv_path_sever(path, NULL);
699                 iucv_path_free(path);
700         }
701 }
702
703 /**
704  * hvc_iucv_notifier_del() - HVC notifier for closing a TTY for the last time.
705  * @hp:         Pointer to the HVC device (struct hvc_struct)
706  * @id:         Additional data (originally passed to hvc_alloc):
707  *              the index of an struct hvc_iucv_private instance.
708  *
709  * This routine notifies the HVC back-end that the last tty device fd has been
710  * closed.  The function cleans up tty resources.  The clean-up of the IUCV
711  * connection is done in hvc_iucv_dtr_rts() and depends on the HUPCL termios
712  * control setting.
713  *
714  * Locking:     struct hvc_iucv_private->lock
715  */
716 static void hvc_iucv_notifier_del(struct hvc_struct *hp, int id)
717 {
718         struct hvc_iucv_private *priv;
719
720         priv = hvc_iucv_get_private(id);
721         if (!priv)
722                 return;
723
724         flush_sndbuf_sync(priv);
725
726         spin_lock_bh(&priv->lock);
727         destroy_tty_buffer_list(&priv->tty_outqueue);
728         destroy_tty_buffer_list(&priv->tty_inqueue);
729         priv->tty_state = TTY_CLOSED;
730         priv->sndbuf_len = 0;
731         spin_unlock_bh(&priv->lock);
732 }
733
734 /**
735  * hvc_iucv_filter_connreq() - Filter connection request based on z/VM user ID
736  * @ipvmid:     Originating z/VM user ID (right padded with blanks)
737  *
738  * Returns 0 if the z/VM user ID that is specified with @ipvmid is permitted to
739  * connect, otherwise non-zero.
740  */
741 static int hvc_iucv_filter_connreq(u8 ipvmid[8])
742 {
743         const char *wildcard, *filter_entry;
744         size_t i, len;
745
746         /* Note: default policy is ACCEPT if no filter is set */
747         if (!hvc_iucv_filter_size)
748                 return 0;
749
750         for (i = 0; i < hvc_iucv_filter_size; i++) {
751                 filter_entry = hvc_iucv_filter + (8 * i);
752
753                 /* If a filter entry contains the filter wildcard character,
754                  * reduce the length to match the leading portion of the user
755                  * ID only (wildcard match).  Characters following the wildcard
756                  * are ignored.
757                  */
758                 wildcard = strnchr(filter_entry, 8, FILTER_WILDCARD_CHAR);
759                 len = (wildcard) ? wildcard - filter_entry : 8;
760                 if (0 == memcmp(ipvmid, filter_entry, len))
761                         return 0;
762         }
763         return 1;
764 }
765
766 /**
767  * hvc_iucv_path_pending() - IUCV handler to process a connection request.
768  * @path:       Pending path (struct iucv_path)
769  * @ipvmid:     z/VM system identifier of originator
770  * @ipuser:     User specified data for this path
771  *              (AF_IUCV: port/service name and originator port)
772  *
773  * The function uses the @ipuser data to determine if the pending path belongs
774  * to a terminal managed by this device driver.
775  * If the path belongs to this driver, ensure that the terminal is not accessed
776  * multiple times (only one connection to a terminal is allowed).
777  * If the terminal is not yet connected, the pending path is accepted and is
778  * associated to the appropriate struct hvc_iucv_private instance.
779  *
780  * Returns 0 if @path belongs to a terminal managed by the this device driver;
781  * otherwise returns -ENODEV in order to dispatch this path to other handlers.
782  *
783  * Locking:     struct hvc_iucv_private->lock
784  */
785 static  int hvc_iucv_path_pending(struct iucv_path *path, u8 *ipvmid,
786                                   u8 *ipuser)
787 {
788         struct hvc_iucv_private *priv, *tmp;
789         u8 wildcard[9] = "lnxhvc  ";
790         int i, rc, find_unused;
791         u8 nuser_data[16];
792         u8 vm_user_id[9];
793
794         ASCEBC(wildcard, sizeof(wildcard));
795         find_unused = !memcmp(wildcard, ipuser, 8);
796
797         /* First, check if the pending path request is managed by this
798          * IUCV handler:
799          * - find a disconnected device if ipuser contains the wildcard
800          * - find the device that matches the terminal ID in ipuser
801          */
802         priv = NULL;
803         for (i = 0; i < hvc_iucv_devices; i++) {
804                 tmp = hvc_iucv_table[i];
805                 if (!tmp)
806                         continue;
807
808                 if (find_unused) {
809                         spin_lock(&tmp->lock);
810                         if (tmp->iucv_state == IUCV_DISCONN)
811                                 priv = tmp;
812                         spin_unlock(&tmp->lock);
813
814                 } else if (!memcmp(tmp->srv_name, ipuser, 8))
815                                 priv = tmp;
816                 if (priv)
817                         break;
818         }
819         if (!priv)
820                 return -ENODEV;
821
822         /* Enforce that ipvmid is allowed to connect to us */
823         read_lock(&hvc_iucv_filter_lock);
824         rc = hvc_iucv_filter_connreq(ipvmid);
825         read_unlock(&hvc_iucv_filter_lock);
826         if (rc) {
827                 iucv_path_sever(path, ipuser);
828                 iucv_path_free(path);
829                 memcpy(vm_user_id, ipvmid, 8);
830                 vm_user_id[8] = 0;
831                 pr_info("A connection request from z/VM user ID %s "
832                         "was refused\n", vm_user_id);
833                 return 0;
834         }
835
836         spin_lock(&priv->lock);
837
838         /* If the terminal is already connected or being severed, then sever
839          * this path to enforce that there is only ONE established communication
840          * path per terminal. */
841         if (priv->iucv_state != IUCV_DISCONN) {
842                 iucv_path_sever(path, ipuser);
843                 iucv_path_free(path);
844                 goto out_path_handled;
845         }
846
847         /* accept path */
848         memcpy(nuser_data, ipuser + 8, 8);  /* remote service (for af_iucv) */
849         memcpy(nuser_data + 8, ipuser, 8);  /* local service  (for af_iucv) */
850         path->msglim = 0xffff;              /* IUCV MSGLIMIT */
851         path->flags &= ~IUCV_IPRMDATA;      /* TODO: use IUCV_IPRMDATA */
852         rc = iucv_path_accept(path, &hvc_iucv_handler, nuser_data, priv);
853         if (rc) {
854                 iucv_path_sever(path, ipuser);
855                 iucv_path_free(path);
856                 goto out_path_handled;
857         }
858         priv->path = path;
859         priv->iucv_state = IUCV_CONNECTED;
860
861         /* store path information */
862         memcpy(priv->info_path, ipvmid, 8);
863         memcpy(priv->info_path + 8, ipuser + 8, 8);
864
865         /* flush buffered output data... */
866         schedule_delayed_work(&priv->sndbuf_work, 5);
867
868 out_path_handled:
869         spin_unlock(&priv->lock);
870         return 0;
871 }
872
873 /**
874  * hvc_iucv_path_severed() - IUCV handler to process a path sever.
875  * @path:       Pending path (struct iucv_path)
876  * @ipuser:     User specified data for this path
877  *              (AF_IUCV: port/service name and originator port)
878  *
879  * This function calls the hvc_iucv_hangup() function for the
880  * respective IUCV HVC terminal.
881  *
882  * Locking:     struct hvc_iucv_private->lock
883  */
884 static void hvc_iucv_path_severed(struct iucv_path *path, u8 *ipuser)
885 {
886         struct hvc_iucv_private *priv = path->private;
887
888         hvc_iucv_hangup(priv);
889 }
890
891 /**
892  * hvc_iucv_msg_pending() - IUCV handler to process an incoming IUCV message.
893  * @path:       Pending path (struct iucv_path)
894  * @msg:        Pointer to the IUCV message
895  *
896  * The function puts an incoming message on the input queue for later
897  * processing (by hvc_iucv_get_chars() / hvc_iucv_write()).
898  * If the tty has not yet been opened, the message is rejected.
899  *
900  * Locking:     struct hvc_iucv_private->lock
901  */
902 static void hvc_iucv_msg_pending(struct iucv_path *path,
903                                  struct iucv_message *msg)
904 {
905         struct hvc_iucv_private *priv = path->private;
906         struct iucv_tty_buffer *rb;
907
908         /* reject messages that exceed max size of iucv_tty_msg->datalen */
909         if (msg->length > MSG_SIZE(MSG_MAX_DATALEN)) {
910                 iucv_message_reject(path, msg);
911                 return;
912         }
913
914         spin_lock(&priv->lock);
915
916         /* reject messages if tty has not yet been opened */
917         if (priv->tty_state == TTY_CLOSED) {
918                 iucv_message_reject(path, msg);
919                 goto unlock_return;
920         }
921
922         /* allocate tty buffer to save iucv msg only */
923         rb = alloc_tty_buffer(0, GFP_ATOMIC);
924         if (!rb) {
925                 iucv_message_reject(path, msg);
926                 goto unlock_return;     /* -ENOMEM */
927         }
928         rb->msg = *msg;
929
930         list_add_tail(&rb->list, &priv->tty_inqueue);
931
932         hvc_kick();     /* wake up hvc thread */
933
934 unlock_return:
935         spin_unlock(&priv->lock);
936 }
937
938 /**
939  * hvc_iucv_msg_complete() - IUCV handler to process message completion
940  * @path:       Pending path (struct iucv_path)
941  * @msg:        Pointer to the IUCV message
942  *
943  * The function is called upon completion of message delivery to remove the
944  * message from the outqueue. Additional delivery information can be found
945  * msg->audit: rejected messages (0x040000 (IPADRJCT)), and
946  *             purged messages   (0x010000 (IPADPGNR)).
947  *
948  * Locking:     struct hvc_iucv_private->lock
949  */
950 static void hvc_iucv_msg_complete(struct iucv_path *path,
951                                   struct iucv_message *msg)
952 {
953         struct hvc_iucv_private *priv = path->private;
954         struct iucv_tty_buffer  *ent, *next;
955         LIST_HEAD(list_remove);
956
957         spin_lock(&priv->lock);
958         list_for_each_entry_safe(ent, next, &priv->tty_outqueue, list)
959                 if (ent->msg.id == msg->id) {
960                         list_move(&ent->list, &list_remove);
961                         break;
962                 }
963         wake_up(&priv->sndbuf_waitq);
964         spin_unlock(&priv->lock);
965         destroy_tty_buffer_list(&list_remove);
966 }
967
968 /**
969  * hvc_iucv_pm_freeze() - Freeze PM callback
970  * @dev:        IUVC HVC terminal device
971  *
972  * Sever an established IUCV communication path and
973  * trigger a hang-up of the underlying HVC terminal.
974  */
975 static int hvc_iucv_pm_freeze(struct device *dev)
976 {
977         struct hvc_iucv_private *priv = dev_get_drvdata(dev);
978
979         local_bh_disable();
980         hvc_iucv_hangup(priv);
981         local_bh_enable();
982
983         return 0;
984 }
985
986 /**
987  * hvc_iucv_pm_restore_thaw() - Thaw and restore PM callback
988  * @dev:        IUVC HVC terminal device
989  *
990  * Wake up the HVC thread to trigger hang-up and respective
991  * HVC back-end notifier invocations.
992  */
993 static int hvc_iucv_pm_restore_thaw(struct device *dev)
994 {
995         hvc_kick();
996         return 0;
997 }
998
999 static ssize_t hvc_iucv_dev_termid_show(struct device *dev,
1000                                         struct device_attribute *attr,
1001                                         char *buf)
1002 {
1003         struct hvc_iucv_private *priv = dev_get_drvdata(dev);
1004         size_t len;
1005
1006         len = sizeof(priv->srv_name);
1007         memcpy(buf, priv->srv_name, len);
1008         EBCASC(buf, len);
1009         buf[len++] = '\n';
1010         return len;
1011 }
1012
1013 static ssize_t hvc_iucv_dev_state_show(struct device *dev,
1014                                         struct device_attribute *attr,
1015                                         char *buf)
1016 {
1017         struct hvc_iucv_private *priv = dev_get_drvdata(dev);
1018         return sprintf(buf, "%u:%u\n", priv->iucv_state, priv->tty_state);
1019 }
1020
1021 static ssize_t hvc_iucv_dev_peer_show(struct device *dev,
1022                                       struct device_attribute *attr,
1023                                       char *buf)
1024 {
1025         struct hvc_iucv_private *priv = dev_get_drvdata(dev);
1026         char vmid[9], ipuser[9];
1027
1028         memset(vmid, 0, sizeof(vmid));
1029         memset(ipuser, 0, sizeof(ipuser));
1030
1031         spin_lock_bh(&priv->lock);
1032         if (priv->iucv_state == IUCV_CONNECTED) {
1033                 memcpy(vmid, priv->info_path, 8);
1034                 memcpy(ipuser, priv->info_path + 8, 8);
1035         }
1036         spin_unlock_bh(&priv->lock);
1037         EBCASC(ipuser, 8);
1038
1039         return sprintf(buf, "%s:%s\n", vmid, ipuser);
1040 }
1041
1042
1043 /* HVC operations */
1044 static const struct hv_ops hvc_iucv_ops = {
1045         .get_chars = hvc_iucv_get_chars,
1046         .put_chars = hvc_iucv_put_chars,
1047         .notifier_add = hvc_iucv_notifier_add,
1048         .notifier_del = hvc_iucv_notifier_del,
1049         .notifier_hangup = hvc_iucv_notifier_hangup,
1050         .dtr_rts = hvc_iucv_dtr_rts,
1051 };
1052
1053 /* Suspend / resume device operations */
1054 static const struct dev_pm_ops hvc_iucv_pm_ops = {
1055         .freeze   = hvc_iucv_pm_freeze,
1056         .thaw     = hvc_iucv_pm_restore_thaw,
1057         .restore  = hvc_iucv_pm_restore_thaw,
1058 };
1059
1060 /* IUCV HVC device driver */
1061 static struct device_driver hvc_iucv_driver = {
1062         .name = KMSG_COMPONENT,
1063         .bus  = &iucv_bus,
1064         .pm   = &hvc_iucv_pm_ops,
1065 };
1066
1067 /* IUCV HVC device attributes */
1068 static DEVICE_ATTR(termid, 0640, hvc_iucv_dev_termid_show, NULL);
1069 static DEVICE_ATTR(state, 0640, hvc_iucv_dev_state_show, NULL);
1070 static DEVICE_ATTR(peer, 0640, hvc_iucv_dev_peer_show, NULL);
1071 static struct attribute *hvc_iucv_dev_attrs[] = {
1072         &dev_attr_termid.attr,
1073         &dev_attr_state.attr,
1074         &dev_attr_peer.attr,
1075         NULL,
1076 };
1077 static struct attribute_group hvc_iucv_dev_attr_group = {
1078         .attrs = hvc_iucv_dev_attrs,
1079 };
1080 static const struct attribute_group *hvc_iucv_dev_attr_groups[] = {
1081         &hvc_iucv_dev_attr_group,
1082         NULL,
1083 };
1084
1085
1086 /**
1087  * hvc_iucv_alloc() - Allocates a new struct hvc_iucv_private instance
1088  * @id:                 hvc_iucv_table index
1089  * @is_console:         Flag if the instance is used as Linux console
1090  *
1091  * This function allocates a new hvc_iucv_private structure and stores
1092  * the instance in hvc_iucv_table at index @id.
1093  * Returns 0 on success; otherwise non-zero.
1094  */
1095 static int __init hvc_iucv_alloc(int id, unsigned int is_console)
1096 {
1097         struct hvc_iucv_private *priv;
1098         char name[9];
1099         int rc;
1100
1101         priv = kzalloc(sizeof(struct hvc_iucv_private), GFP_KERNEL);
1102         if (!priv)
1103                 return -ENOMEM;
1104
1105         spin_lock_init(&priv->lock);
1106         INIT_LIST_HEAD(&priv->tty_outqueue);
1107         INIT_LIST_HEAD(&priv->tty_inqueue);
1108         INIT_DELAYED_WORK(&priv->sndbuf_work, hvc_iucv_sndbuf_work);
1109         init_waitqueue_head(&priv->sndbuf_waitq);
1110
1111         priv->sndbuf = (void *) get_zeroed_page(GFP_KERNEL);
1112         if (!priv->sndbuf) {
1113                 kfree(priv);
1114                 return -ENOMEM;
1115         }
1116
1117         /* set console flag */
1118         priv->is_console = is_console;
1119
1120         /* allocate hvc device */
1121         priv->hvc = hvc_alloc(HVC_IUCV_MAGIC + id, /*             PAGE_SIZE */
1122                               HVC_IUCV_MAGIC + id, &hvc_iucv_ops, 256);
1123         if (IS_ERR(priv->hvc)) {
1124                 rc = PTR_ERR(priv->hvc);
1125                 goto out_error_hvc;
1126         }
1127
1128         /* notify HVC thread instead of using polling */
1129         priv->hvc->irq_requested = 1;
1130
1131         /* setup iucv related information */
1132         snprintf(name, 9, "lnxhvc%-2d", id);
1133         memcpy(priv->srv_name, name, 8);
1134         ASCEBC(priv->srv_name, 8);
1135
1136         /* create and setup device */
1137         priv->dev = kzalloc(sizeof(*priv->dev), GFP_KERNEL);
1138         if (!priv->dev) {
1139                 rc = -ENOMEM;
1140                 goto out_error_dev;
1141         }
1142         dev_set_name(priv->dev, "hvc_iucv%d", id);
1143         dev_set_drvdata(priv->dev, priv);
1144         priv->dev->bus = &iucv_bus;
1145         priv->dev->parent = iucv_root;
1146         priv->dev->driver = &hvc_iucv_driver;
1147         priv->dev->groups = hvc_iucv_dev_attr_groups;
1148         priv->dev->release = (void (*)(struct device *)) kfree;
1149         rc = device_register(priv->dev);
1150         if (rc) {
1151                 put_device(priv->dev);
1152                 goto out_error_dev;
1153         }
1154
1155         hvc_iucv_table[id] = priv;
1156         return 0;
1157
1158 out_error_dev:
1159         hvc_remove(priv->hvc);
1160 out_error_hvc:
1161         free_page((unsigned long) priv->sndbuf);
1162         kfree(priv);
1163
1164         return rc;
1165 }
1166
1167 /**
1168  * hvc_iucv_destroy() - Destroy and free hvc_iucv_private instances
1169  */
1170 static void __init hvc_iucv_destroy(struct hvc_iucv_private *priv)
1171 {
1172         hvc_remove(priv->hvc);
1173         device_unregister(priv->dev);
1174         free_page((unsigned long) priv->sndbuf);
1175         kfree(priv);
1176 }
1177
1178 /**
1179  * hvc_iucv_parse_filter() - Parse filter for a single z/VM user ID
1180  * @filter:     String containing a comma-separated list of z/VM user IDs
1181  * @dest:       Location where to store the parsed z/VM user ID
1182  */
1183 static const char *hvc_iucv_parse_filter(const char *filter, char *dest)
1184 {
1185         const char *nextdelim, *residual;
1186         size_t len;
1187
1188         nextdelim = strchr(filter, ',');
1189         if (nextdelim) {
1190                 len = nextdelim - filter;
1191                 residual = nextdelim + 1;
1192         } else {
1193                 len = strlen(filter);
1194                 residual = filter + len;
1195         }
1196
1197         if (len == 0)
1198                 return ERR_PTR(-EINVAL);
1199
1200         /* check for '\n' (if called from sysfs) */
1201         if (filter[len - 1] == '\n')
1202                 len--;
1203
1204         /* prohibit filter entries containing the wildcard character only */
1205         if (len == 1 && *filter == FILTER_WILDCARD_CHAR)
1206                 return ERR_PTR(-EINVAL);
1207
1208         if (len > 8)
1209                 return ERR_PTR(-EINVAL);
1210
1211         /* pad with blanks and save upper case version of user ID */
1212         memset(dest, ' ', 8);
1213         while (len--)
1214                 dest[len] = toupper(filter[len]);
1215         return residual;
1216 }
1217
1218 /**
1219  * hvc_iucv_setup_filter() - Set up z/VM user ID filter
1220  * @filter:     String consisting of a comma-separated list of z/VM user IDs
1221  *
1222  * The function parses the @filter string and creates an array containing
1223  * the list of z/VM user ID filter entries.
1224  * Return code 0 means success, -EINVAL if the filter is syntactically
1225  * incorrect, -ENOMEM if there was not enough memory to allocate the
1226  * filter list array, or -ENOSPC if too many z/VM user IDs have been specified.
1227  */
1228 static int hvc_iucv_setup_filter(const char *val)
1229 {
1230         const char *residual;
1231         int err;
1232         size_t size, count;
1233         void *array, *old_filter;
1234
1235         count = strlen(val);
1236         if (count == 0 || (count == 1 && val[0] == '\n')) {
1237                 size  = 0;
1238                 array = NULL;
1239                 goto out_replace_filter;        /* clear filter */
1240         }
1241
1242         /* count user IDs in order to allocate sufficient memory */
1243         size = 1;
1244         residual = val;
1245         while ((residual = strchr(residual, ',')) != NULL) {
1246                 residual++;
1247                 size++;
1248         }
1249
1250         /* check if the specified list exceeds the filter limit */
1251         if (size > MAX_VMID_FILTER)
1252                 return -ENOSPC;
1253
1254         array = kzalloc(size * 8, GFP_KERNEL);
1255         if (!array)
1256                 return -ENOMEM;
1257
1258         count = size;
1259         residual = val;
1260         while (*residual && count) {
1261                 residual = hvc_iucv_parse_filter(residual,
1262                                                  array + ((size - count) * 8));
1263                 if (IS_ERR(residual)) {
1264                         err = PTR_ERR(residual);
1265                         kfree(array);
1266                         goto out_err;
1267                 }
1268                 count--;
1269         }
1270
1271 out_replace_filter:
1272         write_lock_bh(&hvc_iucv_filter_lock);
1273         old_filter = hvc_iucv_filter;
1274         hvc_iucv_filter_size = size;
1275         hvc_iucv_filter = array;
1276         write_unlock_bh(&hvc_iucv_filter_lock);
1277         kfree(old_filter);
1278
1279         err = 0;
1280 out_err:
1281         return err;
1282 }
1283
1284 /**
1285  * param_set_vmidfilter() - Set z/VM user ID filter parameter
1286  * @val:        String consisting of a comma-separated list of z/VM user IDs
1287  * @kp:         Kernel parameter pointing to hvc_iucv_filter array
1288  *
1289  * The function sets up the z/VM user ID filter specified as comma-separated
1290  * list of user IDs in @val.
1291  * Note: If it is called early in the boot process, @val is stored and
1292  *       parsed later in hvc_iucv_init().
1293  */
1294 static int param_set_vmidfilter(const char *val, const struct kernel_param *kp)
1295 {
1296         int rc;
1297
1298         if (!MACHINE_IS_VM || !hvc_iucv_devices)
1299                 return -ENODEV;
1300
1301         if (!val)
1302                 return -EINVAL;
1303
1304         rc = 0;
1305         if (slab_is_available())
1306                 rc = hvc_iucv_setup_filter(val);
1307         else
1308                 hvc_iucv_filter_string = val;   /* defer... */
1309         return rc;
1310 }
1311
1312 /**
1313  * param_get_vmidfilter() - Get z/VM user ID filter
1314  * @buffer:     Buffer to store z/VM user ID filter,
1315  *              (buffer size assumption PAGE_SIZE)
1316  * @kp:         Kernel parameter pointing to the hvc_iucv_filter array
1317  *
1318  * The function stores the filter as a comma-separated list of z/VM user IDs
1319  * in @buffer. Typically, sysfs routines call this function for attr show.
1320  */
1321 static int param_get_vmidfilter(char *buffer, const struct kernel_param *kp)
1322 {
1323         int rc;
1324         size_t index, len;
1325         void *start, *end;
1326
1327         if (!MACHINE_IS_VM || !hvc_iucv_devices)
1328                 return -ENODEV;
1329
1330         rc = 0;
1331         read_lock_bh(&hvc_iucv_filter_lock);
1332         for (index = 0; index < hvc_iucv_filter_size; index++) {
1333                 start = hvc_iucv_filter + (8 * index);
1334                 end   = memchr(start, ' ', 8);
1335                 len   = (end) ? end - start : 8;
1336                 memcpy(buffer + rc, start, len);
1337                 rc += len;
1338                 buffer[rc++] = ',';
1339         }
1340         read_unlock_bh(&hvc_iucv_filter_lock);
1341         if (rc)
1342                 buffer[--rc] = '\0';    /* replace last comma and update rc */
1343         return rc;
1344 }
1345
1346 #define param_check_vmidfilter(name, p) __param_check(name, p, void)
1347
1348 static const struct kernel_param_ops param_ops_vmidfilter = {
1349         .set = param_set_vmidfilter,
1350         .get = param_get_vmidfilter,
1351 };
1352
1353 /**
1354  * hvc_iucv_init() - z/VM IUCV HVC device driver initialization
1355  */
1356 static int __init hvc_iucv_init(void)
1357 {
1358         int rc;
1359         unsigned int i;
1360
1361         if (!hvc_iucv_devices)
1362                 return -ENODEV;
1363
1364         if (!MACHINE_IS_VM) {
1365                 pr_notice("The z/VM IUCV HVC device driver cannot "
1366                            "be used without z/VM\n");
1367                 rc = -ENODEV;
1368                 goto out_error;
1369         }
1370
1371         if (hvc_iucv_devices > MAX_HVC_IUCV_LINES) {
1372                 pr_err("%lu is not a valid value for the hvc_iucv= "
1373                         "kernel parameter\n", hvc_iucv_devices);
1374                 rc = -EINVAL;
1375                 goto out_error;
1376         }
1377
1378         /* register IUCV HVC device driver */
1379         rc = driver_register(&hvc_iucv_driver);
1380         if (rc)
1381                 goto out_error;
1382
1383         /* parse hvc_iucv_allow string and create z/VM user ID filter list */
1384         if (hvc_iucv_filter_string) {
1385                 rc = hvc_iucv_setup_filter(hvc_iucv_filter_string);
1386                 switch (rc) {
1387                 case 0:
1388                         break;
1389                 case -ENOMEM:
1390                         pr_err("Allocating memory failed with "
1391                                 "reason code=%d\n", 3);
1392                         goto out_error;
1393                 case -EINVAL:
1394                         pr_err("hvc_iucv_allow= does not specify a valid "
1395                                 "z/VM user ID list\n");
1396                         goto out_error;
1397                 case -ENOSPC:
1398                         pr_err("hvc_iucv_allow= specifies too many "
1399                                 "z/VM user IDs\n");
1400                         goto out_error;
1401                 default:
1402                         goto out_error;
1403                 }
1404         }
1405
1406         hvc_iucv_buffer_cache = kmem_cache_create(KMSG_COMPONENT,
1407                                            sizeof(struct iucv_tty_buffer),
1408                                            0, 0, NULL);
1409         if (!hvc_iucv_buffer_cache) {
1410                 pr_err("Allocating memory failed with reason code=%d\n", 1);
1411                 rc = -ENOMEM;
1412                 goto out_error;
1413         }
1414
1415         hvc_iucv_mempool = mempool_create_slab_pool(MEMPOOL_MIN_NR,
1416                                                     hvc_iucv_buffer_cache);
1417         if (!hvc_iucv_mempool) {
1418                 pr_err("Allocating memory failed with reason code=%d\n", 2);
1419                 kmem_cache_destroy(hvc_iucv_buffer_cache);
1420                 rc = -ENOMEM;
1421                 goto out_error;
1422         }
1423
1424         /* register the first terminal device as console
1425          * (must be done before allocating hvc terminal devices) */
1426         rc = hvc_instantiate(HVC_IUCV_MAGIC, IUCV_HVC_CON_IDX, &hvc_iucv_ops);
1427         if (rc) {
1428                 pr_err("Registering HVC terminal device as "
1429                        "Linux console failed\n");
1430                 goto out_error_memory;
1431         }
1432
1433         /* allocate hvc_iucv_private structs */
1434         for (i = 0; i < hvc_iucv_devices; i++) {
1435                 rc = hvc_iucv_alloc(i, (i == IUCV_HVC_CON_IDX) ? 1 : 0);
1436                 if (rc) {
1437                         pr_err("Creating a new HVC terminal device "
1438                                 "failed with error code=%d\n", rc);
1439                         goto out_error_hvc;
1440                 }
1441         }
1442
1443         /* register IUCV callback handler */
1444         rc = iucv_register(&hvc_iucv_handler, 0);
1445         if (rc) {
1446                 pr_err("Registering IUCV handlers failed with error code=%d\n",
1447                         rc);
1448                 goto out_error_hvc;
1449         }
1450
1451         return 0;
1452
1453 out_error_hvc:
1454         for (i = 0; i < hvc_iucv_devices; i++)
1455                 if (hvc_iucv_table[i])
1456                         hvc_iucv_destroy(hvc_iucv_table[i]);
1457 out_error_memory:
1458         mempool_destroy(hvc_iucv_mempool);
1459         kmem_cache_destroy(hvc_iucv_buffer_cache);
1460 out_error:
1461         kfree(hvc_iucv_filter);
1462         hvc_iucv_devices = 0; /* ensure that we do not provide any device */
1463         return rc;
1464 }
1465
1466 /**
1467  * hvc_iucv_config() - Parsing of hvc_iucv=  kernel command line parameter
1468  * @val:        Parameter value (numeric)
1469  */
1470 static  int __init hvc_iucv_config(char *val)
1471 {
1472         if (kstrtoul(val, 10, &hvc_iucv_devices))
1473                 pr_warn("hvc_iucv= invalid parameter value '%s'\n", val);
1474         return 1;
1475 }
1476
1477
1478 device_initcall(hvc_iucv_init);
1479 __setup("hvc_iucv=", hvc_iucv_config);
1480 core_param(hvc_iucv_allow, hvc_iucv_filter, vmidfilter, 0640);