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44a01d5b HB |
1 | /* |
2 | * hvc_iucv.c - z/VM IUCV back-end for the Hypervisor Console (HVC) | |
3 | * | |
4 | * This back-end for HVC provides terminal access via | |
5 | * z/VM IUCV communication paths. | |
6 | * | |
7 | * Copyright IBM Corp. 2008. | |
8 | * | |
9 | * Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com> | |
10 | */ | |
11 | #define KMSG_COMPONENT "hvc_iucv" | |
12 | ||
13 | #include <linux/types.h> | |
14 | #include <asm/ebcdic.h> | |
15 | #include <linux/mempool.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/tty.h> | |
18 | #include <net/iucv/iucv.h> | |
19 | ||
20 | #include "hvc_console.h" | |
21 | ||
22 | ||
23 | /* HVC backend for z/VM IUCV */ | |
24 | #define HVC_IUCV_MAGIC 0xc9e4c3e5 | |
25 | #define MAX_HVC_IUCV_LINES HVC_ALLOC_TTY_ADAPTERS | |
26 | #define MEMPOOL_MIN_NR (PAGE_SIZE / sizeof(struct iucv_tty_buffer)/4) | |
27 | ||
28 | /* IUCV TTY message */ | |
29 | #define MSG_VERSION 0x02 /* Message version */ | |
30 | #define MSG_TYPE_ERROR 0x01 /* Error message */ | |
31 | #define MSG_TYPE_TERMENV 0x02 /* Terminal environment variable */ | |
32 | #define MSG_TYPE_TERMIOS 0x04 /* Terminal IO struct update */ | |
33 | #define MSG_TYPE_WINSIZE 0x08 /* Terminal window size update */ | |
34 | #define MSG_TYPE_DATA 0x10 /* Terminal data */ | |
35 | ||
36 | #define MSG_SIZE(s) ((s) + offsetof(struct iucv_tty_msg, data)) | |
37 | struct iucv_tty_msg { | |
38 | u8 version; /* Message version */ | |
39 | u8 type; /* Message type */ | |
40 | #define MSG_MAX_DATALEN (~(u16)0) | |
41 | u16 datalen; /* Payload length */ | |
42 | u8 data[]; /* Payload buffer */ | |
43 | } __attribute__((packed)); | |
44 | ||
45 | enum iucv_state_t { | |
46 | IUCV_DISCONN = 0, | |
47 | IUCV_CONNECTED = 1, | |
48 | IUCV_SEVERED = 2, | |
49 | }; | |
50 | ||
51 | enum tty_state_t { | |
52 | TTY_CLOSED = 0, | |
53 | TTY_OPENED = 1, | |
54 | }; | |
55 | ||
56 | struct hvc_iucv_private { | |
57 | struct hvc_struct *hvc; /* HVC console struct reference */ | |
58 | u8 srv_name[8]; /* IUCV service name (ebcdic) */ | |
59 | enum iucv_state_t iucv_state; /* IUCV connection status */ | |
60 | enum tty_state_t tty_state; /* TTY status */ | |
61 | struct iucv_path *path; /* IUCV path pointer */ | |
62 | spinlock_t lock; /* hvc_iucv_private lock */ | |
63 | struct list_head tty_outqueue; /* outgoing IUCV messages */ | |
64 | struct list_head tty_inqueue; /* incoming IUCV messages */ | |
65 | }; | |
66 | ||
67 | struct iucv_tty_buffer { | |
68 | struct list_head list; /* list pointer */ | |
69 | struct iucv_message msg; /* store an incoming IUCV message */ | |
70 | size_t offset; /* data buffer offset */ | |
71 | struct iucv_tty_msg *mbuf; /* buffer to store input/output data */ | |
72 | }; | |
73 | ||
74 | /* IUCV callback handler */ | |
75 | static int hvc_iucv_path_pending(struct iucv_path *, u8[8], u8[16]); | |
76 | static void hvc_iucv_path_severed(struct iucv_path *, u8[16]); | |
77 | static void hvc_iucv_msg_pending(struct iucv_path *, struct iucv_message *); | |
78 | static void hvc_iucv_msg_complete(struct iucv_path *, struct iucv_message *); | |
79 | ||
80 | ||
2dc184c0 HB |
81 | /* Kernel module parameter: use one terminal device as default */ |
82 | static unsigned long hvc_iucv_devices = 1; | |
44a01d5b HB |
83 | |
84 | /* Array of allocated hvc iucv tty lines... */ | |
85 | static struct hvc_iucv_private *hvc_iucv_table[MAX_HVC_IUCV_LINES]; | |
86 | ||
87 | /* Kmem cache and mempool for iucv_tty_buffer elements */ | |
88 | static struct kmem_cache *hvc_iucv_buffer_cache; | |
89 | static mempool_t *hvc_iucv_mempool; | |
90 | ||
91 | /* IUCV handler callback functions */ | |
92 | static struct iucv_handler hvc_iucv_handler = { | |
93 | .path_pending = hvc_iucv_path_pending, | |
94 | .path_severed = hvc_iucv_path_severed, | |
95 | .message_complete = hvc_iucv_msg_complete, | |
96 | .message_pending = hvc_iucv_msg_pending, | |
97 | }; | |
98 | ||
99 | ||
100 | /** | |
101 | * hvc_iucv_get_private() - Return a struct hvc_iucv_private instance. | |
102 | * @num: The HVC virtual terminal number (vtermno) | |
103 | * | |
104 | * This function returns the struct hvc_iucv_private instance that corresponds | |
105 | * to the HVC virtual terminal number specified as parameter @num. | |
106 | */ | |
107 | struct hvc_iucv_private *hvc_iucv_get_private(uint32_t num) | |
108 | { | |
109 | if ((num < HVC_IUCV_MAGIC) || (num - HVC_IUCV_MAGIC > hvc_iucv_devices)) | |
110 | return NULL; | |
111 | return hvc_iucv_table[num - HVC_IUCV_MAGIC]; | |
112 | } | |
113 | ||
114 | /** | |
115 | * alloc_tty_buffer() - Returns a new struct iucv_tty_buffer element. | |
116 | * @size: Size of the internal buffer used to store data. | |
117 | * @flags: Memory allocation flags passed to mempool. | |
118 | * | |
119 | * This function allocates a new struct iucv_tty_buffer element and, optionally, | |
120 | * allocates an internal data buffer with the specified size @size. | |
121 | * Note: The total message size arises from the internal buffer size and the | |
122 | * members of the iucv_tty_msg structure. | |
123 | * | |
124 | * The function returns NULL if memory allocation has failed. | |
125 | */ | |
126 | static struct iucv_tty_buffer *alloc_tty_buffer(size_t size, gfp_t flags) | |
127 | { | |
128 | struct iucv_tty_buffer *bufp; | |
129 | ||
130 | bufp = mempool_alloc(hvc_iucv_mempool, flags); | |
131 | if (!bufp) | |
132 | return NULL; | |
133 | memset(bufp, 0, sizeof(struct iucv_tty_buffer)); | |
134 | ||
135 | if (size > 0) { | |
136 | bufp->msg.length = MSG_SIZE(size); | |
137 | bufp->mbuf = kmalloc(bufp->msg.length, flags); | |
138 | if (!bufp->mbuf) { | |
139 | mempool_free(bufp, hvc_iucv_mempool); | |
140 | return NULL; | |
141 | } | |
142 | bufp->mbuf->version = MSG_VERSION; | |
143 | bufp->mbuf->type = MSG_TYPE_DATA; | |
144 | bufp->mbuf->datalen = (u16) size; | |
145 | } | |
146 | return bufp; | |
147 | } | |
148 | ||
149 | /** | |
150 | * destroy_tty_buffer() - destroy struct iucv_tty_buffer element. | |
151 | * @bufp: Pointer to a struct iucv_tty_buffer element, SHALL NOT be NULL. | |
152 | * | |
153 | * The destroy_tty_buffer() function frees the internal data buffer and returns | |
154 | * the struct iucv_tty_buffer element back to the mempool for freeing. | |
155 | */ | |
156 | static void destroy_tty_buffer(struct iucv_tty_buffer *bufp) | |
157 | { | |
158 | kfree(bufp->mbuf); | |
159 | mempool_free(bufp, hvc_iucv_mempool); | |
160 | } | |
161 | ||
162 | /** | |
163 | * destroy_tty_buffer_list() - call destroy_tty_buffer() for each list element. | |
164 | * @list: List head pointer to a list containing struct iucv_tty_buffer | |
165 | * elements. | |
166 | * | |
167 | * Calls destroy_tty_buffer() for each struct iucv_tty_buffer element in the | |
168 | * list @list. | |
169 | */ | |
170 | static void destroy_tty_buffer_list(struct list_head *list) | |
171 | { | |
172 | struct iucv_tty_buffer *ent, *next; | |
173 | ||
174 | list_for_each_entry_safe(ent, next, list, list) { | |
175 | list_del(&ent->list); | |
176 | destroy_tty_buffer(ent); | |
177 | } | |
178 | } | |
179 | ||
180 | /** | |
181 | * hvc_iucv_write() - Receive IUCV message write data to HVC console buffer. | |
182 | * @priv: Pointer to hvc_iucv_private structure. | |
183 | * @buf: HVC console buffer for writing received terminal data. | |
184 | * @count: HVC console buffer size. | |
185 | * @has_more_data: Pointer to an int variable. | |
186 | * | |
187 | * The function picks up pending messages from the input queue and receives | |
188 | * the message data that is then written to the specified buffer @buf. | |
189 | * If the buffer size @count is less than the data message size, then the | |
190 | * message is kept on the input queue and @has_more_data is set to 1. | |
191 | * If the message data has been entirely written, the message is removed from | |
192 | * the input queue. | |
193 | * | |
194 | * The function returns the number of bytes written to the terminal, zero if | |
195 | * there are no pending data messages available or if there is no established | |
196 | * IUCV path. | |
197 | * If the IUCV path has been severed, then -EPIPE is returned to cause a | |
198 | * hang up (that is issued by the HVC console layer). | |
199 | */ | |
200 | static int hvc_iucv_write(struct hvc_iucv_private *priv, | |
201 | char *buf, int count, int *has_more_data) | |
202 | { | |
203 | struct iucv_tty_buffer *rb; | |
204 | int written; | |
205 | int rc; | |
206 | ||
207 | /* Immediately return if there is no IUCV connection */ | |
208 | if (priv->iucv_state == IUCV_DISCONN) | |
209 | return 0; | |
210 | ||
211 | /* If the IUCV path has been severed, return -EPIPE to inform the | |
212 | * hvc console layer to hang up the tty device. */ | |
213 | if (priv->iucv_state == IUCV_SEVERED) | |
214 | return -EPIPE; | |
215 | ||
216 | /* check if there are pending messages */ | |
217 | if (list_empty(&priv->tty_inqueue)) | |
218 | return 0; | |
219 | ||
220 | /* receive a iucv message and flip data to the tty (ldisc) */ | |
221 | rb = list_first_entry(&priv->tty_inqueue, struct iucv_tty_buffer, list); | |
222 | ||
223 | written = 0; | |
224 | if (!rb->mbuf) { /* message not yet received ... */ | |
225 | /* allocate mem to store msg data; if no memory is available | |
226 | * then leave the buffer on the list and re-try later */ | |
227 | rb->mbuf = kmalloc(rb->msg.length, GFP_ATOMIC); | |
228 | if (!rb->mbuf) | |
229 | return -ENOMEM; | |
230 | ||
231 | rc = __iucv_message_receive(priv->path, &rb->msg, 0, | |
232 | rb->mbuf, rb->msg.length, NULL); | |
233 | switch (rc) { | |
234 | case 0: /* Successful */ | |
235 | break; | |
236 | case 2: /* No message found */ | |
237 | case 9: /* Message purged */ | |
238 | break; | |
239 | default: | |
240 | written = -EIO; | |
241 | } | |
242 | /* remove buffer if an error has occured or received data | |
243 | * is not correct */ | |
244 | if (rc || (rb->mbuf->version != MSG_VERSION) || | |
245 | (rb->msg.length != MSG_SIZE(rb->mbuf->datalen))) | |
246 | goto out_remove_buffer; | |
247 | } | |
248 | ||
249 | switch (rb->mbuf->type) { | |
250 | case MSG_TYPE_DATA: | |
251 | written = min_t(int, rb->mbuf->datalen - rb->offset, count); | |
252 | memcpy(buf, rb->mbuf->data + rb->offset, written); | |
253 | if (written < (rb->mbuf->datalen - rb->offset)) { | |
254 | rb->offset += written; | |
255 | *has_more_data = 1; | |
256 | goto out_written; | |
257 | } | |
258 | break; | |
259 | ||
260 | case MSG_TYPE_WINSIZE: | |
261 | if (rb->mbuf->datalen != sizeof(struct winsize)) | |
262 | break; | |
263 | hvc_resize(priv->hvc, *((struct winsize *)rb->mbuf->data)); | |
264 | break; | |
265 | ||
266 | case MSG_TYPE_ERROR: /* ignored ... */ | |
267 | case MSG_TYPE_TERMENV: /* ignored ... */ | |
268 | case MSG_TYPE_TERMIOS: /* ignored ... */ | |
269 | break; | |
270 | } | |
271 | ||
272 | out_remove_buffer: | |
273 | list_del(&rb->list); | |
274 | destroy_tty_buffer(rb); | |
275 | *has_more_data = !list_empty(&priv->tty_inqueue); | |
276 | ||
277 | out_written: | |
278 | return written; | |
279 | } | |
280 | ||
281 | /** | |
282 | * hvc_iucv_get_chars() - HVC get_chars operation. | |
283 | * @vtermno: HVC virtual terminal number. | |
284 | * @buf: Pointer to a buffer to store data | |
285 | * @count: Size of buffer available for writing | |
286 | * | |
287 | * The hvc_console thread calls this method to read characters from | |
288 | * the terminal backend. If an IUCV communication path has been established, | |
289 | * pending IUCV messages are received and data is copied into buffer @buf | |
290 | * up to @count bytes. | |
291 | * | |
292 | * Locking: The routine gets called under an irqsave() spinlock; and | |
293 | * the routine locks the struct hvc_iucv_private->lock to call | |
294 | * helper functions. | |
295 | */ | |
296 | static int hvc_iucv_get_chars(uint32_t vtermno, char *buf, int count) | |
297 | { | |
298 | struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno); | |
299 | int written; | |
300 | int has_more_data; | |
301 | ||
302 | if (count <= 0) | |
303 | return 0; | |
304 | ||
305 | if (!priv) | |
306 | return -ENODEV; | |
307 | ||
308 | spin_lock(&priv->lock); | |
309 | has_more_data = 0; | |
310 | written = hvc_iucv_write(priv, buf, count, &has_more_data); | |
311 | spin_unlock(&priv->lock); | |
312 | ||
313 | /* if there are still messages on the queue... schedule another run */ | |
314 | if (has_more_data) | |
315 | hvc_kick(); | |
316 | ||
317 | return written; | |
318 | } | |
319 | ||
320 | /** | |
321 | * hvc_iucv_send() - Send an IUCV message containing terminal data. | |
322 | * @priv: Pointer to struct hvc_iucv_private instance. | |
323 | * @buf: Buffer containing data to send. | |
324 | * @size: Size of buffer and amount of data to send. | |
325 | * | |
326 | * If an IUCV communication path is established, the function copies the buffer | |
327 | * data to a newly allocated struct iucv_tty_buffer element, sends the data and | |
328 | * puts the element to the outqueue. | |
329 | * | |
330 | * If there is no IUCV communication path established, the function returns 0. | |
331 | * If an existing IUCV communicaton path has been severed, the function returns | |
332 | * -EPIPE (can be passed to HVC layer to cause a tty hangup). | |
333 | */ | |
334 | static int hvc_iucv_send(struct hvc_iucv_private *priv, const char *buf, | |
335 | int count) | |
336 | { | |
337 | struct iucv_tty_buffer *sb; | |
338 | int rc; | |
339 | u16 len; | |
340 | ||
341 | if (priv->iucv_state == IUCV_SEVERED) | |
342 | return -EPIPE; | |
343 | ||
344 | if (priv->iucv_state == IUCV_DISCONN) | |
345 | return 0; | |
346 | ||
347 | len = min_t(u16, MSG_MAX_DATALEN, count); | |
348 | ||
349 | /* allocate internal buffer to store msg data and also compute total | |
350 | * message length */ | |
351 | sb = alloc_tty_buffer(len, GFP_ATOMIC); | |
352 | if (!sb) | |
353 | return -ENOMEM; | |
354 | ||
355 | sb->mbuf->datalen = len; | |
356 | memcpy(sb->mbuf->data, buf, len); | |
357 | ||
358 | list_add_tail(&sb->list, &priv->tty_outqueue); | |
359 | ||
360 | rc = __iucv_message_send(priv->path, &sb->msg, 0, 0, | |
361 | (void *) sb->mbuf, sb->msg.length); | |
362 | if (rc) { | |
363 | list_del(&sb->list); | |
364 | destroy_tty_buffer(sb); | |
365 | len = 0; | |
366 | } | |
367 | ||
368 | return len; | |
369 | } | |
370 | ||
371 | /** | |
372 | * hvc_iucv_put_chars() - HVC put_chars operation. | |
373 | * @vtermno: HVC virtual terminal number. | |
374 | * @buf: Pointer to an buffer to read data from | |
375 | * @count: Size of buffer available for reading | |
376 | * | |
377 | * The hvc_console thread calls this method to write characters from | |
378 | * to the terminal backend. | |
379 | * The function calls hvc_iucv_send() under the lock of the | |
380 | * struct hvc_iucv_private instance that corresponds to the tty @vtermno. | |
381 | * | |
382 | * Locking: The method gets called under an irqsave() spinlock; and | |
383 | * locks struct hvc_iucv_private->lock. | |
384 | */ | |
385 | static int hvc_iucv_put_chars(uint32_t vtermno, const char *buf, int count) | |
386 | { | |
387 | struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno); | |
388 | int sent; | |
389 | ||
390 | if (count <= 0) | |
391 | return 0; | |
392 | ||
393 | if (!priv) | |
394 | return -ENODEV; | |
395 | ||
396 | spin_lock(&priv->lock); | |
397 | sent = hvc_iucv_send(priv, buf, count); | |
398 | spin_unlock(&priv->lock); | |
399 | ||
400 | return sent; | |
401 | } | |
402 | ||
403 | /** | |
404 | * hvc_iucv_notifier_add() - HVC notifier for opening a TTY for the first time. | |
405 | * @hp: Pointer to the HVC device (struct hvc_struct) | |
406 | * @id: Additional data (originally passed to hvc_alloc): the index of an struct | |
407 | * hvc_iucv_private instance. | |
408 | * | |
409 | * The function sets the tty state to TTY_OPEN for the struct hvc_iucv_private | |
410 | * instance that is derived from @id. Always returns 0. | |
411 | * | |
412 | * Locking: struct hvc_iucv_private->lock, spin_lock_bh | |
413 | */ | |
414 | static int hvc_iucv_notifier_add(struct hvc_struct *hp, int id) | |
415 | { | |
416 | struct hvc_iucv_private *priv; | |
417 | ||
418 | priv = hvc_iucv_get_private(id); | |
419 | if (!priv) | |
420 | return 0; | |
421 | ||
422 | spin_lock_bh(&priv->lock); | |
423 | priv->tty_state = TTY_OPENED; | |
424 | spin_unlock_bh(&priv->lock); | |
425 | ||
426 | return 0; | |
427 | } | |
428 | ||
429 | /** | |
430 | * hvc_iucv_cleanup() - Clean up function if the tty portion is finally closed. | |
431 | * @priv: Pointer to the struct hvc_iucv_private instance. | |
432 | * | |
433 | * The functions severs the established IUCV communication path (if any), and | |
434 | * destroy struct iucv_tty_buffer elements from the in- and outqueue. Finally, | |
435 | * the functions resets the states to TTY_CLOSED and IUCV_DISCONN. | |
436 | */ | |
437 | static void hvc_iucv_cleanup(struct hvc_iucv_private *priv) | |
438 | { | |
439 | destroy_tty_buffer_list(&priv->tty_outqueue); | |
440 | destroy_tty_buffer_list(&priv->tty_inqueue); | |
441 | ||
442 | priv->tty_state = TTY_CLOSED; | |
443 | priv->iucv_state = IUCV_DISCONN; | |
444 | } | |
445 | ||
446 | /** | |
447 | * hvc_iucv_notifier_hangup() - HVC notifier for tty hangups. | |
448 | * @hp: Pointer to the HVC device (struct hvc_struct) | |
449 | * @id: Additional data (originally passed to hvc_alloc): the index of an struct | |
450 | * hvc_iucv_private instance. | |
451 | * | |
452 | * This routine notifies the HVC backend that a tty hangup (carrier loss, | |
453 | * virtual or otherwise) has occured. | |
454 | * | |
455 | * The HVC backend for z/VM IUCV ignores virtual hangups (vhangup()), to keep | |
456 | * an existing IUCV communication path established. | |
457 | * (Background: vhangup() is called from user space (by getty or login) to | |
458 | * disable writing to the tty by other applications). | |
459 | * | |
460 | * If the tty has been opened (e.g. getty) and an established IUCV path has been | |
461 | * severed (we caused the tty hangup in that case), then the functions invokes | |
462 | * hvc_iucv_cleanup() to clean up. | |
463 | * | |
464 | * Locking: struct hvc_iucv_private->lock | |
465 | */ | |
466 | static void hvc_iucv_notifier_hangup(struct hvc_struct *hp, int id) | |
467 | { | |
468 | struct hvc_iucv_private *priv; | |
469 | ||
470 | priv = hvc_iucv_get_private(id); | |
471 | if (!priv) | |
472 | return; | |
473 | ||
474 | spin_lock_bh(&priv->lock); | |
475 | /* NOTE: If the hangup was scheduled by ourself (from the iucv | |
476 | * path_servered callback [IUCV_SEVERED]), then we have to | |
477 | * finally clean up the tty backend structure and set state to | |
478 | * TTY_CLOSED. | |
479 | * | |
480 | * If the tty was hung up otherwise (e.g. vhangup()), then we | |
481 | * ignore this hangup and keep an established IUCV path open... | |
482 | * (...the reason is that we are not able to connect back to the | |
483 | * client if we disconnect on hang up) */ | |
484 | priv->tty_state = TTY_CLOSED; | |
485 | ||
486 | if (priv->iucv_state == IUCV_SEVERED) | |
487 | hvc_iucv_cleanup(priv); | |
488 | spin_unlock_bh(&priv->lock); | |
489 | } | |
490 | ||
491 | /** | |
492 | * hvc_iucv_notifier_del() - HVC notifier for closing a TTY for the last time. | |
493 | * @hp: Pointer to the HVC device (struct hvc_struct) | |
494 | * @id: Additional data (originally passed to hvc_alloc): | |
495 | * the index of an struct hvc_iucv_private instance. | |
496 | * | |
497 | * This routine notifies the HVC backend that the last tty device file | |
498 | * descriptor has been closed. | |
499 | * The function calls hvc_iucv_cleanup() to clean up the struct hvc_iucv_private | |
500 | * instance. | |
501 | * | |
502 | * Locking: struct hvc_iucv_private->lock | |
503 | */ | |
504 | static void hvc_iucv_notifier_del(struct hvc_struct *hp, int id) | |
505 | { | |
506 | struct hvc_iucv_private *priv; | |
507 | struct iucv_path *path; | |
508 | ||
509 | priv = hvc_iucv_get_private(id); | |
510 | if (!priv) | |
511 | return; | |
512 | ||
513 | spin_lock_bh(&priv->lock); | |
514 | path = priv->path; /* save reference to IUCV path */ | |
515 | priv->path = NULL; | |
516 | hvc_iucv_cleanup(priv); | |
517 | spin_unlock_bh(&priv->lock); | |
518 | ||
519 | /* sever IUCV path outside of priv->lock due to lock ordering of: | |
520 | * priv->lock <--> iucv_table_lock */ | |
521 | if (path) { | |
522 | iucv_path_sever(path, NULL); | |
523 | iucv_path_free(path); | |
524 | } | |
525 | } | |
526 | ||
527 | /** | |
528 | * hvc_iucv_path_pending() - IUCV handler to process a connection request. | |
529 | * @path: Pending path (struct iucv_path) | |
530 | * @ipvmid: Originator z/VM system identifier | |
531 | * @ipuser: User specified data for this path | |
532 | * (AF_IUCV: port/service name and originator port) | |
533 | * | |
534 | * The function uses the @ipuser data to check to determine if the pending | |
535 | * path belongs to a terminal managed by this HVC backend. | |
536 | * If the check is successful, then an additional check is done to ensure | |
537 | * that a terminal cannot be accessed multiple times (only one connection | |
538 | * to a terminal is allowed). In that particular case, the pending path is | |
539 | * severed. If it is the first connection, the pending path is accepted and | |
540 | * associated to the struct hvc_iucv_private. The iucv state is updated to | |
541 | * reflect that a communication path has been established. | |
542 | * | |
543 | * Returns 0 if the path belongs to a terminal managed by the this HVC backend; | |
544 | * otherwise returns -ENODEV in order to dispatch this path to other handlers. | |
545 | * | |
546 | * Locking: struct hvc_iucv_private->lock | |
547 | */ | |
548 | static int hvc_iucv_path_pending(struct iucv_path *path, | |
549 | u8 ipvmid[8], u8 ipuser[16]) | |
550 | { | |
551 | struct hvc_iucv_private *priv; | |
552 | u8 nuser_data[16]; | |
553 | int i, rc; | |
554 | ||
555 | priv = NULL; | |
556 | for (i = 0; i < hvc_iucv_devices; i++) | |
557 | if (hvc_iucv_table[i] && | |
558 | (0 == memcmp(hvc_iucv_table[i]->srv_name, ipuser, 8))) { | |
559 | priv = hvc_iucv_table[i]; | |
560 | break; | |
561 | } | |
562 | ||
563 | if (!priv) | |
564 | return -ENODEV; | |
565 | ||
566 | spin_lock(&priv->lock); | |
567 | ||
568 | /* If the terminal is already connected or being severed, then sever | |
569 | * this path to enforce that there is only ONE established communication | |
570 | * path per terminal. */ | |
571 | if (priv->iucv_state != IUCV_DISCONN) { | |
572 | iucv_path_sever(path, ipuser); | |
573 | iucv_path_free(path); | |
574 | goto out_path_handled; | |
575 | } | |
576 | ||
577 | /* accept path */ | |
578 | memcpy(nuser_data, ipuser + 8, 8); /* remote service (for af_iucv) */ | |
579 | memcpy(nuser_data + 8, ipuser, 8); /* local service (for af_iucv) */ | |
580 | path->msglim = 0xffff; /* IUCV MSGLIMIT */ | |
581 | path->flags &= ~IUCV_IPRMDATA; /* TODO: use IUCV_IPRMDATA */ | |
582 | rc = iucv_path_accept(path, &hvc_iucv_handler, nuser_data, priv); | |
583 | if (rc) { | |
584 | iucv_path_sever(path, ipuser); | |
585 | iucv_path_free(path); | |
586 | goto out_path_handled; | |
587 | } | |
588 | priv->path = path; | |
589 | priv->iucv_state = IUCV_CONNECTED; | |
590 | ||
591 | out_path_handled: | |
592 | spin_unlock(&priv->lock); | |
593 | return 0; | |
594 | } | |
595 | ||
596 | /** | |
597 | * hvc_iucv_path_severed() - IUCV handler to process a path sever. | |
598 | * @path: Pending path (struct iucv_path) | |
599 | * @ipuser: User specified data for this path | |
600 | * (AF_IUCV: port/service name and originator port) | |
601 | * | |
602 | * The function also severs the path (as required by the IUCV protocol) and | |
603 | * sets the iucv state to IUCV_SEVERED for the associated struct | |
604 | * hvc_iucv_private instance. Later, the IUCV_SEVERED state triggers a tty | |
605 | * hangup (hvc_iucv_get_chars() / hvc_iucv_write()). | |
606 | * | |
607 | * If tty portion of the HVC is closed then clean up the outqueue in addition. | |
608 | * | |
609 | * Locking: struct hvc_iucv_private->lock | |
610 | */ | |
611 | static void hvc_iucv_path_severed(struct iucv_path *path, u8 ipuser[16]) | |
612 | { | |
613 | struct hvc_iucv_private *priv = path->private; | |
614 | ||
615 | spin_lock(&priv->lock); | |
616 | priv->iucv_state = IUCV_SEVERED; | |
617 | ||
618 | /* NOTE: If the tty has not yet been opened by a getty program | |
619 | * (e.g. to see console messages), then cleanup the | |
620 | * hvc_iucv_private structure to allow re-connects. | |
621 | * | |
622 | * If the tty has been opened, the get_chars() callback returns | |
623 | * -EPIPE to signal the hvc console layer to hang up the tty. */ | |
624 | priv->path = NULL; | |
625 | if (priv->tty_state == TTY_CLOSED) | |
626 | hvc_iucv_cleanup(priv); | |
627 | spin_unlock(&priv->lock); | |
628 | ||
629 | /* finally sever path (outside of priv->lock due to lock ordering) */ | |
630 | iucv_path_sever(path, ipuser); | |
631 | iucv_path_free(path); | |
632 | } | |
633 | ||
634 | /** | |
635 | * hvc_iucv_msg_pending() - IUCV handler to process an incoming IUCV message. | |
636 | * @path: Pending path (struct iucv_path) | |
637 | * @msg: Pointer to the IUCV message | |
638 | * | |
639 | * The function stores an incoming message on the input queue for later | |
640 | * processing (by hvc_iucv_get_chars() / hvc_iucv_write()). | |
641 | * However, if the tty has not yet been opened, the message is rejected. | |
642 | * | |
643 | * Locking: struct hvc_iucv_private->lock | |
644 | */ | |
645 | static void hvc_iucv_msg_pending(struct iucv_path *path, | |
646 | struct iucv_message *msg) | |
647 | { | |
648 | struct hvc_iucv_private *priv = path->private; | |
649 | struct iucv_tty_buffer *rb; | |
650 | ||
651 | spin_lock(&priv->lock); | |
652 | ||
653 | /* reject messages if tty has not yet been opened */ | |
654 | if (priv->tty_state == TTY_CLOSED) { | |
655 | iucv_message_reject(path, msg); | |
656 | goto unlock_return; | |
657 | } | |
658 | ||
659 | /* allocate buffer an empty buffer element */ | |
660 | rb = alloc_tty_buffer(0, GFP_ATOMIC); | |
661 | if (!rb) { | |
662 | iucv_message_reject(path, msg); | |
663 | goto unlock_return; /* -ENOMEM */ | |
664 | } | |
665 | rb->msg = *msg; | |
666 | ||
667 | list_add_tail(&rb->list, &priv->tty_inqueue); | |
668 | ||
669 | hvc_kick(); /* wakup hvc console thread */ | |
670 | ||
671 | unlock_return: | |
672 | spin_unlock(&priv->lock); | |
673 | } | |
674 | ||
675 | /** | |
676 | * hvc_iucv_msg_complete() - IUCV handler to process message completion | |
677 | * @path: Pending path (struct iucv_path) | |
678 | * @msg: Pointer to the IUCV message | |
679 | * | |
680 | * The function is called upon completion of message delivery and the | |
681 | * message is removed from the outqueue. Additional delivery information | |
682 | * can be found in msg->audit: rejected messages (0x040000 (IPADRJCT)) and | |
683 | * purged messages (0x010000 (IPADPGNR)). | |
684 | * | |
685 | * Locking: struct hvc_iucv_private->lock | |
686 | */ | |
687 | static void hvc_iucv_msg_complete(struct iucv_path *path, | |
688 | struct iucv_message *msg) | |
689 | { | |
690 | struct hvc_iucv_private *priv = path->private; | |
691 | struct iucv_tty_buffer *ent, *next; | |
692 | LIST_HEAD(list_remove); | |
693 | ||
694 | spin_lock(&priv->lock); | |
695 | list_for_each_entry_safe(ent, next, &priv->tty_outqueue, list) | |
696 | if (ent->msg.id == msg->id) { | |
697 | list_move(&ent->list, &list_remove); | |
698 | break; | |
699 | } | |
700 | spin_unlock(&priv->lock); | |
701 | destroy_tty_buffer_list(&list_remove); | |
702 | } | |
703 | ||
704 | ||
705 | /* HVC operations */ | |
706 | static struct hv_ops hvc_iucv_ops = { | |
707 | .get_chars = hvc_iucv_get_chars, | |
708 | .put_chars = hvc_iucv_put_chars, | |
709 | .notifier_add = hvc_iucv_notifier_add, | |
710 | .notifier_del = hvc_iucv_notifier_del, | |
711 | .notifier_hangup = hvc_iucv_notifier_hangup, | |
712 | }; | |
713 | ||
714 | /** | |
715 | * hvc_iucv_alloc() - Allocates a new struct hvc_iucv_private instance | |
716 | * @id: hvc_iucv_table index | |
717 | * | |
718 | * This function allocates a new hvc_iucv_private struct and put the | |
719 | * instance into hvc_iucv_table at index @id. | |
720 | * Returns 0 on success; otherwise non-zero. | |
721 | */ | |
722 | static int __init hvc_iucv_alloc(int id) | |
723 | { | |
724 | struct hvc_iucv_private *priv; | |
725 | char name[9]; | |
726 | int rc; | |
727 | ||
728 | priv = kzalloc(sizeof(struct hvc_iucv_private), GFP_KERNEL); | |
729 | if (!priv) | |
730 | return -ENOMEM; | |
731 | ||
732 | spin_lock_init(&priv->lock); | |
733 | INIT_LIST_HEAD(&priv->tty_outqueue); | |
734 | INIT_LIST_HEAD(&priv->tty_inqueue); | |
735 | ||
736 | /* Finally allocate hvc */ | |
737 | priv->hvc = hvc_alloc(HVC_IUCV_MAGIC + id, | |
738 | HVC_IUCV_MAGIC + id, &hvc_iucv_ops, PAGE_SIZE); | |
739 | if (IS_ERR(priv->hvc)) { | |
740 | rc = PTR_ERR(priv->hvc); | |
741 | kfree(priv); | |
742 | return rc; | |
743 | } | |
744 | ||
745 | /* setup iucv related information */ | |
2dc184c0 | 746 | snprintf(name, 9, "lnxhvc%-2d", id); |
44a01d5b HB |
747 | memcpy(priv->srv_name, name, 8); |
748 | ASCEBC(priv->srv_name, 8); | |
749 | ||
750 | hvc_iucv_table[id] = priv; | |
751 | return 0; | |
752 | } | |
753 | ||
754 | /** | |
755 | * hvc_iucv_init() - Initialization of HVC backend for z/VM IUCV | |
756 | */ | |
757 | static int __init hvc_iucv_init(void) | |
758 | { | |
759 | int rc, i; | |
760 | ||
761 | if (!MACHINE_IS_VM) { | |
762 | pr_warning("The z/VM IUCV Hypervisor console cannot be " | |
763 | "used without z/VM.\n"); | |
764 | return -ENODEV; | |
765 | } | |
766 | ||
767 | if (!hvc_iucv_devices) | |
768 | return -ENODEV; | |
769 | ||
770 | if (hvc_iucv_devices > MAX_HVC_IUCV_LINES) | |
771 | return -EINVAL; | |
772 | ||
773 | hvc_iucv_buffer_cache = kmem_cache_create(KMSG_COMPONENT, | |
774 | sizeof(struct iucv_tty_buffer), | |
775 | 0, 0, NULL); | |
776 | if (!hvc_iucv_buffer_cache) { | |
777 | pr_err("Not enough memory for driver initialization " | |
778 | "(rs=%d).\n", 1); | |
779 | return -ENOMEM; | |
780 | } | |
781 | ||
782 | hvc_iucv_mempool = mempool_create_slab_pool(MEMPOOL_MIN_NR, | |
783 | hvc_iucv_buffer_cache); | |
784 | if (!hvc_iucv_mempool) { | |
785 | pr_err("Not enough memory for driver initialization " | |
786 | "(rs=%d).\n", 2); | |
787 | kmem_cache_destroy(hvc_iucv_buffer_cache); | |
788 | return -ENOMEM; | |
789 | } | |
790 | ||
791 | /* allocate hvc_iucv_private structs */ | |
792 | for (i = 0; i < hvc_iucv_devices; i++) { | |
793 | rc = hvc_iucv_alloc(i); | |
794 | if (rc) { | |
795 | pr_err("Could not create new z/VM IUCV HVC backend " | |
796 | "rc=%d.\n", rc); | |
797 | goto out_error_hvc; | |
798 | } | |
799 | } | |
800 | ||
801 | /* register IUCV callback handler */ | |
802 | rc = iucv_register(&hvc_iucv_handler, 0); | |
803 | if (rc) { | |
804 | pr_err("Could not register iucv handler (rc=%d).\n", rc); | |
805 | goto out_error_iucv; | |
806 | } | |
807 | ||
808 | return 0; | |
809 | ||
810 | out_error_iucv: | |
811 | iucv_unregister(&hvc_iucv_handler, 0); | |
812 | out_error_hvc: | |
813 | for (i = 0; i < hvc_iucv_devices; i++) | |
814 | if (hvc_iucv_table[i]) { | |
815 | if (hvc_iucv_table[i]->hvc) | |
816 | hvc_remove(hvc_iucv_table[i]->hvc); | |
817 | kfree(hvc_iucv_table[i]); | |
818 | } | |
819 | mempool_destroy(hvc_iucv_mempool); | |
820 | kmem_cache_destroy(hvc_iucv_buffer_cache); | |
821 | return rc; | |
822 | } | |
823 | ||
824 | /** | |
825 | * hvc_iucv_console_init() - Early console initialization | |
826 | */ | |
827 | static int __init hvc_iucv_console_init(void) | |
828 | { | |
829 | if (!MACHINE_IS_VM || !hvc_iucv_devices) | |
830 | return -ENODEV; | |
831 | return hvc_instantiate(HVC_IUCV_MAGIC, 0, &hvc_iucv_ops); | |
832 | } | |
833 | ||
834 | /** | |
835 | * hvc_iucv_config() - Parsing of hvc_iucv= kernel command line parameter | |
836 | * @val: Parameter value (numeric) | |
837 | */ | |
838 | static int __init hvc_iucv_config(char *val) | |
839 | { | |
840 | return strict_strtoul(val, 10, &hvc_iucv_devices); | |
841 | } | |
842 | ||
843 | ||
844 | module_init(hvc_iucv_init); | |
845 | console_initcall(hvc_iucv_console_init); | |
846 | __setup("hvc_iucv=", hvc_iucv_config); | |
847 | ||
848 | MODULE_LICENSE("GPL"); | |
849 | MODULE_DESCRIPTION("HVC back-end for z/VM IUCV."); | |
850 | MODULE_AUTHOR("Hendrik Brueckner <brueckner@linux.vnet.ibm.com>"); |