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
48static char mon_dcss_name[9] = "MONDCSS\0";
49
50struct mon_msg {
51	u32 pos;
52	u32 mca_offset;
53	struct iucv_message msg;
54	char msglim_reached;
55	char replied_msglim;
56};
57
58struct 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
69static unsigned long mon_in_use = 0;
70
71static unsigned long mon_dcss_start;
72static unsigned long mon_dcss_end;
73
74static DECLARE_WAIT_QUEUE_HEAD(mon_read_wait_queue);
75static DECLARE_WAIT_QUEUE_HEAD(mon_conn_wait_queue);
76
77static 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
87static 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 */
100static 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 */
118static 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
164static inline unsigned long mon_mca_start(struct mon_msg *monmsg)
165{
166	return *(u32 *) &monmsg->msg.rmmsg;
167}
168
169static inline unsigned long mon_mca_end(struct mon_msg *monmsg)
170{
171	return *(u32 *) &monmsg->msg.rmmsg[4];
172}
173
174static 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
179static inline u32 mon_mca_size(struct mon_msg *monmsg)
180{
181	return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1;
182}
183
184static inline u32 mon_rec_start(struct mon_msg *monmsg)
185{
186	return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 4));
187}
188
189static inline u32 mon_rec_end(struct mon_msg *monmsg)
190{
191	return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 8));
192}
193
194static 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
212static 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
239static 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
249static 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
271static 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
301static 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
310static 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 *****************************************************************************/
335static 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
347static 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
358static 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
376static 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 *****************************************************************************/
385static 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
432out_path:
433	kfree(monpriv->path);
434out_priv:
435	mon_free_mem(monpriv);
436out_use:
437	clear_bit(MON_IN_USE, &mon_in_use);
438out:
439	return rc;
440}
441
442static 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
470static 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	}
529reply:
530	ret = mon_send_reply(monmsg, monpriv);
531	return ret;
532
533out_copy:
534	*ppos += count;
535	return count;
536}
537
538static 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
550static 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
558static struct miscdevice mon_dev = {
559	.name       = "monreader",
560	.fops       = &mon_fops,
561	.minor      = MISC_DYNAMIC_MINOR,
562};
563
564/******************************************************************************
565 *                              module init/exit                              *
566 *****************************************************************************/
567static 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
617out:
618	segment_unload(mon_dcss_name);
619out_iucv:
620	iucv_unregister(&monreader_iucv_handler, 1);
621	return rc;
622}
623
624static 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
633module_init(mon_init);
634module_exit(mon_exit);
635
636module_param_string(mondcss, mon_dcss_name, 9, 0444);
637MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR "
638		 "service, max. 8 chars. Default is MONDCSS");
639
640MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>");
641MODULE_DESCRIPTION("Character device driver for reading z/VM "
642		   "monitor service records.");
643MODULE_LICENSE("GPL");
644