Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6
[linux-2.6] / drivers / s390 / char / monreader.c
1 /*
2  * drivers/s390/char/monreader.c
3  *
4  * Character device driver for reading z/VM *MONITOR service records.
5  *
6  * Copyright 2004 IBM Corporation, IBM Deutschland Entwicklung GmbH.
7  *
8  * Author: Gerald Schaefer <geraldsc@de.ibm.com>
9  */
10
11 #include <linux/module.h>
12 #include <linux/moduleparam.h>
13 #include <linux/init.h>
14 #include <linux/errno.h>
15 #include <linux/types.h>
16 #include <linux/kernel.h>
17 #include <linux/miscdevice.h>
18 #include <linux/ctype.h>
19 #include <linux/spinlock.h>
20 #include <linux/interrupt.h>
21 #include <asm/uaccess.h>
22 #include <asm/ebcdic.h>
23 #include <asm/extmem.h>
24 #include <linux/poll.h>
25 #include <net/iucv/iucv.h>
26
27
28 //#define MON_DEBUG                     /* Debug messages on/off */
29
30 #define MON_NAME "monreader"
31
32 #define P_INFO(x...)    printk(KERN_INFO MON_NAME " info: " x)
33 #define P_ERROR(x...)   printk(KERN_ERR MON_NAME " error: " x)
34 #define P_WARNING(x...) printk(KERN_WARNING MON_NAME " warning: " x)
35
36 #ifdef MON_DEBUG
37 #define P_DEBUG(x...)   printk(KERN_DEBUG MON_NAME " debug: " x)
38 #else
39 #define P_DEBUG(x...)   do {} while (0)
40 #endif
41
42 #define MON_COLLECT_SAMPLE 0x80
43 #define MON_COLLECT_EVENT  0x40
44 #define MON_SERVICE        "*MONITOR"
45 #define MON_IN_USE         0x01
46 #define MON_MSGLIM         255
47
48 static char mon_dcss_name[9] = "MONDCSS\0";
49
50 struct mon_msg {
51         u32 pos;
52         u32 mca_offset;
53         struct iucv_message msg;
54         char msglim_reached;
55         char replied_msglim;
56 };
57
58 struct mon_private {
59         struct iucv_path *path;
60         struct mon_msg *msg_array[MON_MSGLIM];
61         unsigned int   write_index;
62         unsigned int   read_index;
63         atomic_t msglim_count;
64         atomic_t read_ready;
65         atomic_t iucv_connected;
66         atomic_t iucv_severed;
67 };
68
69 static unsigned long mon_in_use = 0;
70
71 static unsigned long mon_dcss_start;
72 static unsigned long mon_dcss_end;
73
74 static DECLARE_WAIT_QUEUE_HEAD(mon_read_wait_queue);
75 static DECLARE_WAIT_QUEUE_HEAD(mon_conn_wait_queue);
76
77 static u8 user_data_connect[16] = {
78         /* Version code, must be 0x01 for shared mode */
79         0x01,
80         /* what to collect */
81         MON_COLLECT_SAMPLE | MON_COLLECT_EVENT,
82         /* DCSS name in EBCDIC, 8 bytes padded with blanks */
83         0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
84         0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
85 };
86
87 static u8 user_data_sever[16] = {
88         0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
89         0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
90 };
91
92
93 /******************************************************************************
94  *                             helper functions                               *
95  *****************************************************************************/
96 /*
97  * Create the 8 bytes EBCDIC DCSS segment name from
98  * an ASCII name, incl. padding
99  */
100 static void dcss_mkname(char *ascii_name, char *ebcdic_name)
101 {
102         int i;
103
104         for (i = 0; i < 8; i++) {
105                 if (ascii_name[i] == '\0')
106                         break;
107                 ebcdic_name[i] = toupper(ascii_name[i]);
108         };
109         for (; i < 8; i++)
110                 ebcdic_name[i] = ' ';
111         ASCEBC(ebcdic_name, 8);
112 }
113
114 /*
115  * print appropriate error message for segment_load()/segment_type()
116  * return code
117  */
118 static void mon_segment_warn(int rc, char* seg_name)
119 {
120         switch (rc) {
121         case -ENOENT:
122                 P_WARNING("cannot load/query segment %s, does not exist\n",
123                           seg_name);
124                 break;
125         case -ENOSYS:
126                 P_WARNING("cannot load/query segment %s, not running on VM\n",
127                           seg_name);
128                 break;
129         case -EIO:
130                 P_WARNING("cannot load/query segment %s, hardware error\n",
131                           seg_name);
132                 break;
133         case -ENOTSUPP:
134                 P_WARNING("cannot load/query segment %s, is a multi-part "
135                           "segment\n", seg_name);
136                 break;
137         case -ENOSPC:
138                 P_WARNING("cannot load/query segment %s, overlaps with "
139                           "storage\n", seg_name);
140                 break;
141         case -EBUSY:
142                 P_WARNING("cannot load/query segment %s, overlaps with "
143                           "already loaded dcss\n", seg_name);
144                 break;
145         case -EPERM:
146                 P_WARNING("cannot load/query segment %s, already loaded in "
147                           "incompatible mode\n", seg_name);
148                 break;
149         case -ENOMEM:
150                 P_WARNING("cannot load/query segment %s, out of memory\n",
151                           seg_name);
152                 break;
153         case -ERANGE:
154                 P_WARNING("cannot load/query segment %s, exceeds kernel "
155                           "mapping range\n", seg_name);
156                 break;
157         default:
158                 P_WARNING("cannot load/query segment %s, return value %i\n",
159                           seg_name, rc);
160                 break;
161         }
162 }
163
164 static inline unsigned long mon_mca_start(struct mon_msg *monmsg)
165 {
166         return *(u32 *) &monmsg->msg.rmmsg;
167 }
168
169 static inline unsigned long mon_mca_end(struct mon_msg *monmsg)
170 {
171         return *(u32 *) &monmsg->msg.rmmsg[4];
172 }
173
174 static inline u8 mon_mca_type(struct mon_msg *monmsg, u8 index)
175 {
176         return *((u8 *) mon_mca_start(monmsg) + monmsg->mca_offset + index);
177 }
178
179 static inline u32 mon_mca_size(struct mon_msg *monmsg)
180 {
181         return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1;
182 }
183
184 static inline u32 mon_rec_start(struct mon_msg *monmsg)
185 {
186         return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 4));
187 }
188
189 static inline u32 mon_rec_end(struct mon_msg *monmsg)
190 {
191         return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 8));
192 }
193
194 static int mon_check_mca(struct mon_msg *monmsg)
195 {
196         if ((mon_rec_end(monmsg) <= mon_rec_start(monmsg)) ||
197             (mon_rec_start(monmsg) < mon_dcss_start) ||
198             (mon_rec_end(monmsg) > mon_dcss_end) ||
199             (mon_mca_type(monmsg, 0) == 0) ||
200             (mon_mca_size(monmsg) % 12 != 0) ||
201             (mon_mca_end(monmsg) <= mon_mca_start(monmsg)) ||
202             (mon_mca_end(monmsg) > mon_dcss_end) ||
203             (mon_mca_start(monmsg) < mon_dcss_start) ||
204             ((mon_mca_type(monmsg, 1) == 0) && (mon_mca_type(monmsg, 2) == 0)))
205         {
206                 P_DEBUG("READ, IGNORED INVALID MCA\n\n");
207                 return -EINVAL;
208         }
209         return 0;
210 }
211
212 static int mon_send_reply(struct mon_msg *monmsg,
213                           struct mon_private *monpriv)
214 {
215         int rc;
216
217         P_DEBUG("read, REPLY: pathid = 0x%04X, msgid = 0x%08X, trgcls = "
218                 "0x%08X\n\n",
219                 monpriv->path->pathid, monmsg->msg.id, monmsg->msg.class);
220
221         rc = iucv_message_reply(monpriv->path, &monmsg->msg,
222                                 IUCV_IPRMDATA, NULL, 0);
223         atomic_dec(&monpriv->msglim_count);
224         if (likely(!monmsg->msglim_reached)) {
225                 monmsg->pos = 0;
226                 monmsg->mca_offset = 0;
227                 monpriv->read_index = (monpriv->read_index + 1) %
228                                       MON_MSGLIM;
229                 atomic_dec(&monpriv->read_ready);
230         } else
231                 monmsg->replied_msglim = 1;
232         if (rc) {
233                 P_ERROR("read, IUCV reply failed with rc = %i\n\n", rc);
234                 return -EIO;
235         }
236         return 0;
237 }
238
239 static void mon_free_mem(struct mon_private *monpriv)
240 {
241         int i;
242
243         for (i = 0; i < MON_MSGLIM; i++)
244                 if (monpriv->msg_array[i])
245                         kfree(monpriv->msg_array[i]);
246         kfree(monpriv);
247 }
248
249 static struct mon_private *mon_alloc_mem(void)
250 {
251         int i;
252         struct mon_private *monpriv;
253
254         monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
255         if (!monpriv) {
256                 P_ERROR("no memory for monpriv\n");
257                 return NULL;
258         }
259         for (i = 0; i < MON_MSGLIM; i++) {
260                 monpriv->msg_array[i] = kzalloc(sizeof(struct mon_msg),
261                                                     GFP_KERNEL);
262                 if (!monpriv->msg_array[i]) {
263                         P_ERROR("open, no memory for msg_array\n");
264                         mon_free_mem(monpriv);
265                         return NULL;
266                 }
267         }
268         return monpriv;
269 }
270
271 static inline void mon_read_debug(struct mon_msg *monmsg,
272                                   struct mon_private *monpriv)
273 {
274 #ifdef MON_DEBUG
275         u8 msg_type[2], mca_type;
276         unsigned long records_len;
277
278         records_len = mon_rec_end(monmsg) - mon_rec_start(monmsg) + 1;
279
280         memcpy(msg_type, &monmsg->msg.class, 2);
281         EBCASC(msg_type, 2);
282         mca_type = mon_mca_type(monmsg, 0);
283         EBCASC(&mca_type, 1);
284
285         P_DEBUG("read, mon_read_index = %i, mon_write_index = %i\n",
286                 monpriv->read_index, monpriv->write_index);
287         P_DEBUG("read, pathid = 0x%04X, msgid = 0x%08X, trgcls = 0x%08X\n",
288                 monpriv->path->pathid, monmsg->msg.id, monmsg->msg.class);
289         P_DEBUG("read, msg_type = '%c%c', mca_type = '%c' / 0x%X / 0x%X\n",
290                 msg_type[0], msg_type[1], mca_type ? mca_type : 'X',
291                 mon_mca_type(monmsg, 1), mon_mca_type(monmsg, 2));
292         P_DEBUG("read, MCA: start = 0x%lX, end = 0x%lX\n",
293                 mon_mca_start(monmsg), mon_mca_end(monmsg));
294         P_DEBUG("read, REC: start = 0x%X, end = 0x%X, len = %lu\n\n",
295                 mon_rec_start(monmsg), mon_rec_end(monmsg), records_len);
296         if (mon_mca_size(monmsg) > 12)
297                 P_DEBUG("READ, MORE THAN ONE MCA\n\n");
298 #endif
299 }
300
301 static inline void mon_next_mca(struct mon_msg *monmsg)
302 {
303         if (likely((mon_mca_size(monmsg) - monmsg->mca_offset) == 12))
304                 return;
305         P_DEBUG("READ, NEXT MCA\n\n");
306         monmsg->mca_offset += 12;
307         monmsg->pos = 0;
308 }
309
310 static struct mon_msg *mon_next_message(struct mon_private *monpriv)
311 {
312         struct mon_msg *monmsg;
313
314         if (!atomic_read(&monpriv->read_ready))
315                 return NULL;
316         monmsg = monpriv->msg_array[monpriv->read_index];
317         if (unlikely(monmsg->replied_msglim)) {
318                 monmsg->replied_msglim = 0;
319                 monmsg->msglim_reached = 0;
320                 monmsg->pos = 0;
321                 monmsg->mca_offset = 0;
322                 P_WARNING("read, message limit reached\n");
323                 monpriv->read_index = (monpriv->read_index + 1) %
324                                       MON_MSGLIM;
325                 atomic_dec(&monpriv->read_ready);
326                 return ERR_PTR(-EOVERFLOW);
327         }
328         return monmsg;
329 }
330
331
332 /******************************************************************************
333  *                               IUCV handler                                 *
334  *****************************************************************************/
335 static void mon_iucv_path_complete(struct iucv_path *path, u8 ipuser[16])
336 {
337         struct mon_private *monpriv = path->private;
338
339         P_DEBUG("IUCV connection completed\n");
340         P_DEBUG("IUCV ACCEPT (from *MONITOR): Version = 0x%02X, Event = "
341                 "0x%02X, Sample = 0x%02X\n",
342                 ipuser[0], ipuser[1], ipuser[2]);
343         atomic_set(&monpriv->iucv_connected, 1);
344         wake_up(&mon_conn_wait_queue);
345 }
346
347 static void mon_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
348 {
349         struct mon_private *monpriv = path->private;
350
351         P_ERROR("IUCV connection severed with rc = 0x%X\n", ipuser[0]);
352         iucv_path_sever(path, NULL);
353         atomic_set(&monpriv->iucv_severed, 1);
354         wake_up(&mon_conn_wait_queue);
355         wake_up_interruptible(&mon_read_wait_queue);
356 }
357
358 static void mon_iucv_message_pending(struct iucv_path *path,
359                                      struct iucv_message *msg)
360 {
361         struct mon_private *monpriv = path->private;
362
363         P_DEBUG("IUCV message pending\n");
364         memcpy(&monpriv->msg_array[monpriv->write_index]->msg,
365                msg, sizeof(*msg));
366         if (atomic_inc_return(&monpriv->msglim_count) == MON_MSGLIM) {
367                 P_WARNING("IUCV message pending, message limit (%i) reached\n",
368                           MON_MSGLIM);
369                 monpriv->msg_array[monpriv->write_index]->msglim_reached = 1;
370         }
371         monpriv->write_index = (monpriv->write_index + 1) % MON_MSGLIM;
372         atomic_inc(&monpriv->read_ready);
373         wake_up_interruptible(&mon_read_wait_queue);
374 }
375
376 static struct iucv_handler monreader_iucv_handler = {
377         .path_complete   = mon_iucv_path_complete,
378         .path_severed    = mon_iucv_path_severed,
379         .message_pending = mon_iucv_message_pending,
380 };
381
382 /******************************************************************************
383  *                               file operations                              *
384  *****************************************************************************/
385 static int mon_open(struct inode *inode, struct file *filp)
386 {
387         struct mon_private *monpriv;
388         int rc;
389
390         /*
391          * only one user allowed
392          */
393         rc = -EBUSY;
394         if (test_and_set_bit(MON_IN_USE, &mon_in_use))
395                 goto out;
396
397         rc = -ENOMEM;
398         monpriv = mon_alloc_mem();
399         if (!monpriv)
400                 goto out_use;
401
402         /*
403          * Connect to *MONITOR service
404          */
405         monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
406         if (!monpriv->path)
407                 goto out_priv;
408         rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
409                                MON_SERVICE, NULL, user_data_connect, monpriv);
410         if (rc) {
411                 P_ERROR("iucv connection to *MONITOR failed with "
412                         "IPUSER SEVER code = %i\n", rc);
413                 rc = -EIO;
414                 goto out_path;
415         }
416         /*
417          * Wait for connection confirmation
418          */
419         wait_event(mon_conn_wait_queue,
420                    atomic_read(&monpriv->iucv_connected) ||
421                    atomic_read(&monpriv->iucv_severed));
422         if (atomic_read(&monpriv->iucv_severed)) {
423                 atomic_set(&monpriv->iucv_severed, 0);
424                 atomic_set(&monpriv->iucv_connected, 0);
425                 rc = -EIO;
426                 goto out_path;
427         }
428         P_INFO("open, established connection to *MONITOR service\n\n");
429         filp->private_data = monpriv;
430         return nonseekable_open(inode, filp);
431
432 out_path:
433         kfree(monpriv->path);
434 out_priv:
435         mon_free_mem(monpriv);
436 out_use:
437         clear_bit(MON_IN_USE, &mon_in_use);
438 out:
439         return rc;
440 }
441
442 static int mon_close(struct inode *inode, struct file *filp)
443 {
444         int rc, i;
445         struct mon_private *monpriv = filp->private_data;
446
447         /*
448          * Close IUCV connection and unregister
449          */
450         rc = iucv_path_sever(monpriv->path, user_data_sever);
451         if (rc)
452                 P_ERROR("close, iucv_sever failed with rc = %i\n", rc);
453         else
454                 P_INFO("close, terminated connection to *MONITOR service\n");
455
456         atomic_set(&monpriv->iucv_severed, 0);
457         atomic_set(&monpriv->iucv_connected, 0);
458         atomic_set(&monpriv->read_ready, 0);
459         atomic_set(&monpriv->msglim_count, 0);
460         monpriv->write_index  = 0;
461         monpriv->read_index   = 0;
462
463         for (i = 0; i < MON_MSGLIM; i++)
464                 kfree(monpriv->msg_array[i]);
465         kfree(monpriv);
466         clear_bit(MON_IN_USE, &mon_in_use);
467         return 0;
468 }
469
470 static ssize_t mon_read(struct file *filp, char __user *data,
471                         size_t count, loff_t *ppos)
472 {
473         struct mon_private *monpriv = filp->private_data;
474         struct mon_msg *monmsg;
475         int ret;
476         u32 mce_start;
477
478         monmsg = mon_next_message(monpriv);
479         if (IS_ERR(monmsg))
480                 return PTR_ERR(monmsg);
481
482         if (!monmsg) {
483                 if (filp->f_flags & O_NONBLOCK)
484                         return -EAGAIN;
485                 ret = wait_event_interruptible(mon_read_wait_queue,
486                                         atomic_read(&monpriv->read_ready) ||
487                                         atomic_read(&monpriv->iucv_severed));
488                 if (ret)
489                         return ret;
490                 if (unlikely(atomic_read(&monpriv->iucv_severed)))
491                         return -EIO;
492                 monmsg = monpriv->msg_array[monpriv->read_index];
493         }
494
495         if (!monmsg->pos) {
496                 monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset;
497                 mon_read_debug(monmsg, monpriv);
498         }
499         if (mon_check_mca(monmsg))
500                 goto reply;
501
502         /* read monitor control element (12 bytes) first */
503         mce_start = mon_mca_start(monmsg) + monmsg->mca_offset;
504         if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) {
505                 count = min(count, (size_t) mce_start + 12 - monmsg->pos);
506                 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
507                                    count);
508                 if (ret)
509                         return -EFAULT;
510                 monmsg->pos += count;
511                 if (monmsg->pos == mce_start + 12)
512                         monmsg->pos = mon_rec_start(monmsg);
513                 goto out_copy;
514         }
515
516         /* read records */
517         if (monmsg->pos <= mon_rec_end(monmsg)) {
518                 count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos
519                                             + 1);
520                 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
521                                    count);
522                 if (ret)
523                         return -EFAULT;
524                 monmsg->pos += count;
525                 if (monmsg->pos > mon_rec_end(monmsg))
526                         mon_next_mca(monmsg);
527                 goto out_copy;
528         }
529 reply:
530         ret = mon_send_reply(monmsg, monpriv);
531         return ret;
532
533 out_copy:
534         *ppos += count;
535         return count;
536 }
537
538 static unsigned int mon_poll(struct file *filp, struct poll_table_struct *p)
539 {
540         struct mon_private *monpriv = filp->private_data;
541
542         poll_wait(filp, &mon_read_wait_queue, p);
543         if (unlikely(atomic_read(&monpriv->iucv_severed)))
544                 return POLLERR;
545         if (atomic_read(&monpriv->read_ready))
546                 return POLLIN | POLLRDNORM;
547         return 0;
548 }
549
550 static const struct file_operations mon_fops = {
551         .owner   = THIS_MODULE,
552         .open    = &mon_open,
553         .release = &mon_close,
554         .read    = &mon_read,
555         .poll    = &mon_poll,
556 };
557
558 static struct miscdevice mon_dev = {
559         .name       = "monreader",
560         .fops       = &mon_fops,
561         .minor      = MISC_DYNAMIC_MINOR,
562 };
563
564 /******************************************************************************
565  *                              module init/exit                              *
566  *****************************************************************************/
567 static int __init mon_init(void)
568 {
569         int rc;
570
571         if (!MACHINE_IS_VM) {
572                 P_ERROR("not running under z/VM, driver not loaded\n");
573                 return -ENODEV;
574         }
575
576         /*
577          * Register with IUCV and connect to *MONITOR service
578          */
579         rc = iucv_register(&monreader_iucv_handler, 1);
580         if (rc) {
581                 P_ERROR("failed to register with iucv driver\n");
582                 return rc;
583         }
584         P_INFO("open, registered with IUCV\n");
585
586         rc = segment_type(mon_dcss_name);
587         if (rc < 0) {
588                 mon_segment_warn(rc, mon_dcss_name);
589                 goto out_iucv;
590         }
591         if (rc != SEG_TYPE_SC) {
592                 P_ERROR("segment %s has unsupported type, should be SC\n",
593                         mon_dcss_name);
594                 rc = -EINVAL;
595                 goto out_iucv;
596         }
597
598         rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
599                           &mon_dcss_start, &mon_dcss_end);
600         if (rc < 0) {
601                 mon_segment_warn(rc, mon_dcss_name);
602                 rc = -EINVAL;
603                 goto out_iucv;
604         }
605         dcss_mkname(mon_dcss_name, &user_data_connect[8]);
606
607         rc = misc_register(&mon_dev);
608         if (rc < 0 ) {
609                 P_ERROR("misc_register failed, rc = %i\n", rc);
610                 goto out;
611         }
612         P_INFO("Loaded segment %s from %p to %p, size = %lu Byte\n",
613                 mon_dcss_name, (void *) mon_dcss_start, (void *) mon_dcss_end,
614                 mon_dcss_end - mon_dcss_start + 1);
615         return 0;
616
617 out:
618         segment_unload(mon_dcss_name);
619 out_iucv:
620         iucv_unregister(&monreader_iucv_handler, 1);
621         return rc;
622 }
623
624 static void __exit mon_exit(void)
625 {
626         segment_unload(mon_dcss_name);
627         WARN_ON(misc_deregister(&mon_dev) != 0);
628         iucv_unregister(&monreader_iucv_handler, 1);
629         return;
630 }
631
632
633 module_init(mon_init);
634 module_exit(mon_exit);
635
636 module_param_string(mondcss, mon_dcss_name, 9, 0444);
637 MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR "
638                  "service, max. 8 chars. Default is MONDCSS");
639
640 MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>");
641 MODULE_DESCRIPTION("Character device driver for reading z/VM "
642                    "monitor service records.");
643 MODULE_LICENSE("GPL");