Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * Character device driver for reading z/VM *MONITOR service records.
3 *
4 * Copyright IBM Corp. 2004, 2009
5 *
6 * Author: Gerald Schaefer <gerald.schaefer@de.ibm.com>
7 */
8
9#define KMSG_COMPONENT "monreader"
10#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
11
12#include <linux/module.h>
13#include <linux/moduleparam.h>
14#include <linux/init.h>
15#include <linux/smp_lock.h>
16#include <linux/errno.h>
17#include <linux/types.h>
18#include <linux/kernel.h>
19#include <linux/miscdevice.h>
20#include <linux/ctype.h>
21#include <linux/spinlock.h>
22#include <linux/interrupt.h>
23#include <linux/poll.h>
24#include <linux/device.h>
25#include <net/iucv/iucv.h>
26#include <asm/uaccess.h>
27#include <asm/ebcdic.h>
28#include <asm/extmem.h>
29
30
31#define MON_COLLECT_SAMPLE 0x80
32#define MON_COLLECT_EVENT 0x40
33#define MON_SERVICE "*MONITOR"
34#define MON_IN_USE 0x01
35#define MON_MSGLIM 255
36
37static char mon_dcss_name[9] = "MONDCSS\0";
38
39struct mon_msg {
40 u32 pos;
41 u32 mca_offset;
42 struct iucv_message msg;
43 char msglim_reached;
44 char replied_msglim;
45};
46
47struct mon_private {
48 struct iucv_path *path;
49 struct mon_msg *msg_array[MON_MSGLIM];
50 unsigned int write_index;
51 unsigned int read_index;
52 atomic_t msglim_count;
53 atomic_t read_ready;
54 atomic_t iucv_connected;
55 atomic_t iucv_severed;
56};
57
58static unsigned long mon_in_use = 0;
59
60static unsigned long mon_dcss_start;
61static unsigned long mon_dcss_end;
62
63static DECLARE_WAIT_QUEUE_HEAD(mon_read_wait_queue);
64static DECLARE_WAIT_QUEUE_HEAD(mon_conn_wait_queue);
65
66static u8 user_data_connect[16] = {
67 /* Version code, must be 0x01 for shared mode */
68 0x01,
69 /* what to collect */
70 MON_COLLECT_SAMPLE | MON_COLLECT_EVENT,
71 /* DCSS name in EBCDIC, 8 bytes padded with blanks */
72 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
73 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
74};
75
76static u8 user_data_sever[16] = {
77 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
78 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
79};
80
81static struct device *monreader_device;
82
83/******************************************************************************
84 * helper functions *
85 *****************************************************************************/
86/*
87 * Create the 8 bytes EBCDIC DCSS segment name from
88 * an ASCII name, incl. padding
89 */
90static void dcss_mkname(char *ascii_name, char *ebcdic_name)
91{
92 int i;
93
94 for (i = 0; i < 8; i++) {
95 if (ascii_name[i] == '\0')
96 break;
97 ebcdic_name[i] = toupper(ascii_name[i]);
98 };
99 for (; i < 8; i++)
100 ebcdic_name[i] = ' ';
101 ASCEBC(ebcdic_name, 8);
102}
103
104static inline unsigned long mon_mca_start(struct mon_msg *monmsg)
105{
106 return *(u32 *) &monmsg->msg.rmmsg;
107}
108
109static inline unsigned long mon_mca_end(struct mon_msg *monmsg)
110{
111 return *(u32 *) &monmsg->msg.rmmsg[4];
112}
113
114static inline u8 mon_mca_type(struct mon_msg *monmsg, u8 index)
115{
116 return *((u8 *) mon_mca_start(monmsg) + monmsg->mca_offset + index);
117}
118
119static inline u32 mon_mca_size(struct mon_msg *monmsg)
120{
121 return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1;
122}
123
124static inline u32 mon_rec_start(struct mon_msg *monmsg)
125{
126 return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 4));
127}
128
129static inline u32 mon_rec_end(struct mon_msg *monmsg)
130{
131 return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 8));
132}
133
134static int mon_check_mca(struct mon_msg *monmsg)
135{
136 if ((mon_rec_end(monmsg) <= mon_rec_start(monmsg)) ||
137 (mon_rec_start(monmsg) < mon_dcss_start) ||
138 (mon_rec_end(monmsg) > mon_dcss_end) ||
139 (mon_mca_type(monmsg, 0) == 0) ||
140 (mon_mca_size(monmsg) % 12 != 0) ||
141 (mon_mca_end(monmsg) <= mon_mca_start(monmsg)) ||
142 (mon_mca_end(monmsg) > mon_dcss_end) ||
143 (mon_mca_start(monmsg) < mon_dcss_start) ||
144 ((mon_mca_type(monmsg, 1) == 0) && (mon_mca_type(monmsg, 2) == 0)))
145 return -EINVAL;
146 return 0;
147}
148
149static int mon_send_reply(struct mon_msg *monmsg,
150 struct mon_private *monpriv)
151{
152 int rc;
153
154 rc = iucv_message_reply(monpriv->path, &monmsg->msg,
155 IUCV_IPRMDATA, NULL, 0);
156 atomic_dec(&monpriv->msglim_count);
157 if (likely(!monmsg->msglim_reached)) {
158 monmsg->pos = 0;
159 monmsg->mca_offset = 0;
160 monpriv->read_index = (monpriv->read_index + 1) %
161 MON_MSGLIM;
162 atomic_dec(&monpriv->read_ready);
163 } else
164 monmsg->replied_msglim = 1;
165 if (rc) {
166 pr_err("Reading monitor data failed with rc=%i\n", rc);
167 return -EIO;
168 }
169 return 0;
170}
171
172static void mon_free_mem(struct mon_private *monpriv)
173{
174 int i;
175
176 for (i = 0; i < MON_MSGLIM; i++)
177 if (monpriv->msg_array[i])
178 kfree(monpriv->msg_array[i]);
179 kfree(monpriv);
180}
181
182static struct mon_private *mon_alloc_mem(void)
183{
184 int i;
185 struct mon_private *monpriv;
186
187 monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
188 if (!monpriv)
189 return NULL;
190 for (i = 0; i < MON_MSGLIM; i++) {
191 monpriv->msg_array[i] = kzalloc(sizeof(struct mon_msg),
192 GFP_KERNEL);
193 if (!monpriv->msg_array[i]) {
194 mon_free_mem(monpriv);
195 return NULL;
196 }
197 }
198 return monpriv;
199}
200
201static inline void mon_next_mca(struct mon_msg *monmsg)
202{
203 if (likely((mon_mca_size(monmsg) - monmsg->mca_offset) == 12))
204 return;
205 monmsg->mca_offset += 12;
206 monmsg->pos = 0;
207}
208
209static struct mon_msg *mon_next_message(struct mon_private *monpriv)
210{
211 struct mon_msg *monmsg;
212
213 if (!atomic_read(&monpriv->read_ready))
214 return NULL;
215 monmsg = monpriv->msg_array[monpriv->read_index];
216 if (unlikely(monmsg->replied_msglim)) {
217 monmsg->replied_msglim = 0;
218 monmsg->msglim_reached = 0;
219 monmsg->pos = 0;
220 monmsg->mca_offset = 0;
221 monpriv->read_index = (monpriv->read_index + 1) %
222 MON_MSGLIM;
223 atomic_dec(&monpriv->read_ready);
224 return ERR_PTR(-EOVERFLOW);
225 }
226 return monmsg;
227}
228
229
230/******************************************************************************
231 * IUCV handler *
232 *****************************************************************************/
233static void mon_iucv_path_complete(struct iucv_path *path, u8 ipuser[16])
234{
235 struct mon_private *monpriv = path->private;
236
237 atomic_set(&monpriv->iucv_connected, 1);
238 wake_up(&mon_conn_wait_queue);
239}
240
241static void mon_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
242{
243 struct mon_private *monpriv = path->private;
244
245 pr_err("z/VM *MONITOR system service disconnected with rc=%i\n",
246 ipuser[0]);
247 iucv_path_sever(path, NULL);
248 atomic_set(&monpriv->iucv_severed, 1);
249 wake_up(&mon_conn_wait_queue);
250 wake_up_interruptible(&mon_read_wait_queue);
251}
252
253static void mon_iucv_message_pending(struct iucv_path *path,
254 struct iucv_message *msg)
255{
256 struct mon_private *monpriv = path->private;
257
258 memcpy(&monpriv->msg_array[monpriv->write_index]->msg,
259 msg, sizeof(*msg));
260 if (atomic_inc_return(&monpriv->msglim_count) == MON_MSGLIM) {
261 pr_warning("The read queue for monitor data is full\n");
262 monpriv->msg_array[monpriv->write_index]->msglim_reached = 1;
263 }
264 monpriv->write_index = (monpriv->write_index + 1) % MON_MSGLIM;
265 atomic_inc(&monpriv->read_ready);
266 wake_up_interruptible(&mon_read_wait_queue);
267}
268
269static struct iucv_handler monreader_iucv_handler = {
270 .path_complete = mon_iucv_path_complete,
271 .path_severed = mon_iucv_path_severed,
272 .message_pending = mon_iucv_message_pending,
273};
274
275/******************************************************************************
276 * file operations *
277 *****************************************************************************/
278static int mon_open(struct inode *inode, struct file *filp)
279{
280 struct mon_private *monpriv;
281 int rc;
282
283 /*
284 * only one user allowed
285 */
286 lock_kernel();
287 rc = -EBUSY;
288 if (test_and_set_bit(MON_IN_USE, &mon_in_use))
289 goto out;
290
291 rc = -ENOMEM;
292 monpriv = mon_alloc_mem();
293 if (!monpriv)
294 goto out_use;
295
296 /*
297 * Connect to *MONITOR service
298 */
299 monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
300 if (!monpriv->path)
301 goto out_priv;
302 rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
303 MON_SERVICE, NULL, user_data_connect, monpriv);
304 if (rc) {
305 pr_err("Connecting to the z/VM *MONITOR system service "
306 "failed with rc=%i\n", rc);
307 rc = -EIO;
308 goto out_path;
309 }
310 /*
311 * Wait for connection confirmation
312 */
313 wait_event(mon_conn_wait_queue,
314 atomic_read(&monpriv->iucv_connected) ||
315 atomic_read(&monpriv->iucv_severed));
316 if (atomic_read(&monpriv->iucv_severed)) {
317 atomic_set(&monpriv->iucv_severed, 0);
318 atomic_set(&monpriv->iucv_connected, 0);
319 rc = -EIO;
320 goto out_path;
321 }
322 filp->private_data = monpriv;
323 dev_set_drvdata(monreader_device, monpriv);
324 unlock_kernel();
325 return nonseekable_open(inode, filp);
326
327out_path:
328 iucv_path_free(monpriv->path);
329out_priv:
330 mon_free_mem(monpriv);
331out_use:
332 clear_bit(MON_IN_USE, &mon_in_use);
333out:
334 unlock_kernel();
335 return rc;
336}
337
338static int mon_close(struct inode *inode, struct file *filp)
339{
340 int rc, i;
341 struct mon_private *monpriv = filp->private_data;
342
343 /*
344 * Close IUCV connection and unregister
345 */
346 if (monpriv->path) {
347 rc = iucv_path_sever(monpriv->path, user_data_sever);
348 if (rc)
349 pr_warning("Disconnecting the z/VM *MONITOR system "
350 "service failed with rc=%i\n", rc);
351 iucv_path_free(monpriv->path);
352 }
353
354 atomic_set(&monpriv->iucv_severed, 0);
355 atomic_set(&monpriv->iucv_connected, 0);
356 atomic_set(&monpriv->read_ready, 0);
357 atomic_set(&monpriv->msglim_count, 0);
358 monpriv->write_index = 0;
359 monpriv->read_index = 0;
360
361 for (i = 0; i < MON_MSGLIM; i++)
362 kfree(monpriv->msg_array[i]);
363 kfree(monpriv);
364 clear_bit(MON_IN_USE, &mon_in_use);
365 return 0;
366}
367
368static ssize_t mon_read(struct file *filp, char __user *data,
369 size_t count, loff_t *ppos)
370{
371 struct mon_private *monpriv = filp->private_data;
372 struct mon_msg *monmsg;
373 int ret;
374 u32 mce_start;
375
376 monmsg = mon_next_message(monpriv);
377 if (IS_ERR(monmsg))
378 return PTR_ERR(monmsg);
379
380 if (!monmsg) {
381 if (filp->f_flags & O_NONBLOCK)
382 return -EAGAIN;
383 ret = wait_event_interruptible(mon_read_wait_queue,
384 atomic_read(&monpriv->read_ready) ||
385 atomic_read(&monpriv->iucv_severed));
386 if (ret)
387 return ret;
388 if (unlikely(atomic_read(&monpriv->iucv_severed)))
389 return -EIO;
390 monmsg = monpriv->msg_array[monpriv->read_index];
391 }
392
393 if (!monmsg->pos)
394 monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset;
395 if (mon_check_mca(monmsg))
396 goto reply;
397
398 /* read monitor control element (12 bytes) first */
399 mce_start = mon_mca_start(monmsg) + monmsg->mca_offset;
400 if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) {
401 count = min(count, (size_t) mce_start + 12 - monmsg->pos);
402 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
403 count);
404 if (ret)
405 return -EFAULT;
406 monmsg->pos += count;
407 if (monmsg->pos == mce_start + 12)
408 monmsg->pos = mon_rec_start(monmsg);
409 goto out_copy;
410 }
411
412 /* read records */
413 if (monmsg->pos <= mon_rec_end(monmsg)) {
414 count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos
415 + 1);
416 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
417 count);
418 if (ret)
419 return -EFAULT;
420 monmsg->pos += count;
421 if (monmsg->pos > mon_rec_end(monmsg))
422 mon_next_mca(monmsg);
423 goto out_copy;
424 }
425reply:
426 ret = mon_send_reply(monmsg, monpriv);
427 return ret;
428
429out_copy:
430 *ppos += count;
431 return count;
432}
433
434static unsigned int mon_poll(struct file *filp, struct poll_table_struct *p)
435{
436 struct mon_private *monpriv = filp->private_data;
437
438 poll_wait(filp, &mon_read_wait_queue, p);
439 if (unlikely(atomic_read(&monpriv->iucv_severed)))
440 return POLLERR;
441 if (atomic_read(&monpriv->read_ready))
442 return POLLIN | POLLRDNORM;
443 return 0;
444}
445
446static const struct file_operations mon_fops = {
447 .owner = THIS_MODULE,
448 .open = &mon_open,
449 .release = &mon_close,
450 .read = &mon_read,
451 .poll = &mon_poll,
452};
453
454static struct miscdevice mon_dev = {
455 .name = "monreader",
456 .fops = &mon_fops,
457 .minor = MISC_DYNAMIC_MINOR,
458};
459
460
461/******************************************************************************
462 * suspend / resume *
463 *****************************************************************************/
464static int monreader_freeze(struct device *dev)
465{
466 struct mon_private *monpriv = dev_get_drvdata(dev);
467 int rc;
468
469 if (!monpriv)
470 return 0;
471 if (monpriv->path) {
472 rc = iucv_path_sever(monpriv->path, user_data_sever);
473 if (rc)
474 pr_warning("Disconnecting the z/VM *MONITOR system "
475 "service failed with rc=%i\n", rc);
476 iucv_path_free(monpriv->path);
477 }
478 atomic_set(&monpriv->iucv_severed, 0);
479 atomic_set(&monpriv->iucv_connected, 0);
480 atomic_set(&monpriv->read_ready, 0);
481 atomic_set(&monpriv->msglim_count, 0);
482 monpriv->write_index = 0;
483 monpriv->read_index = 0;
484 monpriv->path = NULL;
485 return 0;
486}
487
488static int monreader_thaw(struct device *dev)
489{
490 struct mon_private *monpriv = dev_get_drvdata(dev);
491 int rc;
492
493 if (!monpriv)
494 return 0;
495 rc = -ENOMEM;
496 monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
497 if (!monpriv->path)
498 goto out;
499 rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
500 MON_SERVICE, NULL, user_data_connect, monpriv);
501 if (rc) {
502 pr_err("Connecting to the z/VM *MONITOR system service "
503 "failed with rc=%i\n", rc);
504 goto out_path;
505 }
506 wait_event(mon_conn_wait_queue,
507 atomic_read(&monpriv->iucv_connected) ||
508 atomic_read(&monpriv->iucv_severed));
509 if (atomic_read(&monpriv->iucv_severed))
510 goto out_path;
511 return 0;
512out_path:
513 rc = -EIO;
514 iucv_path_free(monpriv->path);
515 monpriv->path = NULL;
516out:
517 atomic_set(&monpriv->iucv_severed, 1);
518 return rc;
519}
520
521static int monreader_restore(struct device *dev)
522{
523 int rc;
524
525 segment_unload(mon_dcss_name);
526 rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
527 &mon_dcss_start, &mon_dcss_end);
528 if (rc < 0) {
529 segment_warning(rc, mon_dcss_name);
530 panic("fatal monreader resume error: no monitor dcss\n");
531 }
532 return monreader_thaw(dev);
533}
534
535static struct dev_pm_ops monreader_pm_ops = {
536 .freeze = monreader_freeze,
537 .thaw = monreader_thaw,
538 .restore = monreader_restore,
539};
540
541static struct device_driver monreader_driver = {
542 .name = "monreader",
543 .bus = &iucv_bus,
544 .pm = &monreader_pm_ops,
545};
546
547
548/******************************************************************************
549 * module init/exit *
550 *****************************************************************************/
551static int __init mon_init(void)
552{
553 int rc;
554
555 if (!MACHINE_IS_VM) {
556 pr_err("The z/VM *MONITOR record device driver cannot be "
557 "loaded without z/VM\n");
558 return -ENODEV;
559 }
560
561 /*
562 * Register with IUCV and connect to *MONITOR service
563 */
564 rc = iucv_register(&monreader_iucv_handler, 1);
565 if (rc) {
566 pr_err("The z/VM *MONITOR record device driver failed to "
567 "register with IUCV\n");
568 return rc;
569 }
570
571 rc = driver_register(&monreader_driver);
572 if (rc)
573 goto out_iucv;
574 monreader_device = kzalloc(sizeof(struct device), GFP_KERNEL);
575 if (!monreader_device)
576 goto out_driver;
577 dev_set_name(monreader_device, "monreader-dev");
578 monreader_device->bus = &iucv_bus;
579 monreader_device->parent = iucv_root;
580 monreader_device->driver = &monreader_driver;
581 monreader_device->release = (void (*)(struct device *))kfree;
582 rc = device_register(monreader_device);
583 if (rc) {
584 kfree(monreader_device);
585 goto out_driver;
586 }
587
588 rc = segment_type(mon_dcss_name);
589 if (rc < 0) {
590 segment_warning(rc, mon_dcss_name);
591 goto out_device;
592 }
593 if (rc != SEG_TYPE_SC) {
594 pr_err("The specified *MONITOR DCSS %s does not have the "
595 "required type SC\n", mon_dcss_name);
596 rc = -EINVAL;
597 goto out_device;
598 }
599
600 rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
601 &mon_dcss_start, &mon_dcss_end);
602 if (rc < 0) {
603 segment_warning(rc, mon_dcss_name);
604 rc = -EINVAL;
605 goto out_device;
606 }
607 dcss_mkname(mon_dcss_name, &user_data_connect[8]);
608
609 rc = misc_register(&mon_dev);
610 if (rc < 0 )
611 goto out;
612 return 0;
613
614out:
615 segment_unload(mon_dcss_name);
616out_device:
617 device_unregister(monreader_device);
618out_driver:
619 driver_unregister(&monreader_driver);
620out_iucv:
621 iucv_unregister(&monreader_iucv_handler, 1);
622 return rc;
623}
624
625static void __exit mon_exit(void)
626{
627 segment_unload(mon_dcss_name);
628 WARN_ON(misc_deregister(&mon_dev) != 0);
629 device_unregister(monreader_device);
630 driver_unregister(&monreader_driver);
631 iucv_unregister(&monreader_iucv_handler, 1);
632 return;
633}
634
635
636module_init(mon_init);
637module_exit(mon_exit);
638
639module_param_string(mondcss, mon_dcss_name, 9, 0444);
640MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR "
641 "service, max. 8 chars. Default is MONDCSS");
642
643MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>");
644MODULE_DESCRIPTION("Character device driver for reading z/VM "
645 "monitor service records.");
646MODULE_LICENSE("GPL");