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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Character device driver for reading z/VM *MONITOR service records.
4 *
5 * Copyright IBM Corp. 2004, 2009
6 *
7 * Author: Gerald Schaefer <gerald.schaefer@de.ibm.com>
8 */
9
10#define KMSG_COMPONENT "monreader"
11#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
12
13#include <linux/module.h>
14#include <linux/moduleparam.h>
15#include <linux/init.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/slab.h>
25#include <net/iucv/iucv.h>
26#include <linux/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
81/******************************************************************************
82 * helper functions *
83 *****************************************************************************/
84/*
85 * Create the 8 bytes EBCDIC DCSS segment name from
86 * an ASCII name, incl. padding
87 */
88static void dcss_mkname(char *ascii_name, char *ebcdic_name)
89{
90 int i;
91
92 for (i = 0; i < 8; i++) {
93 if (ascii_name[i] == '\0')
94 break;
95 ebcdic_name[i] = toupper(ascii_name[i]);
96 }
97 for (; i < 8; i++)
98 ebcdic_name[i] = ' ';
99 ASCEBC(ebcdic_name, 8);
100}
101
102static inline unsigned long mon_mca_start(struct mon_msg *monmsg)
103{
104 return *(u32 *) &monmsg->msg.rmmsg;
105}
106
107static inline unsigned long mon_mca_end(struct mon_msg *monmsg)
108{
109 return *(u32 *) &monmsg->msg.rmmsg[4];
110}
111
112static inline u8 mon_mca_type(struct mon_msg *monmsg, u8 index)
113{
114 return *((u8 *)__va(mon_mca_start(monmsg)) + monmsg->mca_offset + index);
115}
116
117static inline u32 mon_mca_size(struct mon_msg *monmsg)
118{
119 return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1;
120}
121
122static inline u32 mon_rec_start(struct mon_msg *monmsg)
123{
124 return *((u32 *)(__va(mon_mca_start(monmsg)) + monmsg->mca_offset + 4));
125}
126
127static inline u32 mon_rec_end(struct mon_msg *monmsg)
128{
129 return *((u32 *)(__va(mon_mca_start(monmsg)) + monmsg->mca_offset + 8));
130}
131
132static int mon_check_mca(struct mon_msg *monmsg)
133{
134 if ((mon_rec_end(monmsg) <= mon_rec_start(monmsg)) ||
135 (mon_rec_start(monmsg) < mon_dcss_start) ||
136 (mon_rec_end(monmsg) > mon_dcss_end) ||
137 (mon_mca_type(monmsg, 0) == 0) ||
138 (mon_mca_size(monmsg) % 12 != 0) ||
139 (mon_mca_end(monmsg) <= mon_mca_start(monmsg)) ||
140 (mon_mca_end(monmsg) > mon_dcss_end) ||
141 (mon_mca_start(monmsg) < mon_dcss_start) ||
142 ((mon_mca_type(monmsg, 1) == 0) && (mon_mca_type(monmsg, 2) == 0)))
143 return -EINVAL;
144 return 0;
145}
146
147static int mon_send_reply(struct mon_msg *monmsg,
148 struct mon_private *monpriv)
149{
150 int rc;
151
152 rc = iucv_message_reply(monpriv->path, &monmsg->msg,
153 IUCV_IPRMDATA, NULL, 0);
154 atomic_dec(&monpriv->msglim_count);
155 if (likely(!monmsg->msglim_reached)) {
156 monmsg->pos = 0;
157 monmsg->mca_offset = 0;
158 monpriv->read_index = (monpriv->read_index + 1) %
159 MON_MSGLIM;
160 atomic_dec(&monpriv->read_ready);
161 } else
162 monmsg->replied_msglim = 1;
163 if (rc) {
164 pr_err("Reading monitor data failed with rc=%i\n", rc);
165 return -EIO;
166 }
167 return 0;
168}
169
170static void mon_free_mem(struct mon_private *monpriv)
171{
172 int i;
173
174 for (i = 0; i < MON_MSGLIM; i++)
175 kfree(monpriv->msg_array[i]);
176 kfree(monpriv);
177}
178
179static struct mon_private *mon_alloc_mem(void)
180{
181 int i;
182 struct mon_private *monpriv;
183
184 monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
185 if (!monpriv)
186 return NULL;
187 for (i = 0; i < MON_MSGLIM; i++) {
188 monpriv->msg_array[i] = kzalloc(sizeof(struct mon_msg),
189 GFP_KERNEL);
190 if (!monpriv->msg_array[i]) {
191 mon_free_mem(monpriv);
192 return NULL;
193 }
194 }
195 return monpriv;
196}
197
198static inline void mon_next_mca(struct mon_msg *monmsg)
199{
200 if (likely((mon_mca_size(monmsg) - monmsg->mca_offset) == 12))
201 return;
202 monmsg->mca_offset += 12;
203 monmsg->pos = 0;
204}
205
206static struct mon_msg *mon_next_message(struct mon_private *monpriv)
207{
208 struct mon_msg *monmsg;
209
210 if (!atomic_read(&monpriv->read_ready))
211 return NULL;
212 monmsg = monpriv->msg_array[monpriv->read_index];
213 if (unlikely(monmsg->replied_msglim)) {
214 monmsg->replied_msglim = 0;
215 monmsg->msglim_reached = 0;
216 monmsg->pos = 0;
217 monmsg->mca_offset = 0;
218 monpriv->read_index = (monpriv->read_index + 1) %
219 MON_MSGLIM;
220 atomic_dec(&monpriv->read_ready);
221 return ERR_PTR(-EOVERFLOW);
222 }
223 return monmsg;
224}
225
226
227/******************************************************************************
228 * IUCV handler *
229 *****************************************************************************/
230static void mon_iucv_path_complete(struct iucv_path *path, u8 *ipuser)
231{
232 struct mon_private *monpriv = path->private;
233
234 atomic_set(&monpriv->iucv_connected, 1);
235 wake_up(&mon_conn_wait_queue);
236}
237
238static void mon_iucv_path_severed(struct iucv_path *path, u8 *ipuser)
239{
240 struct mon_private *monpriv = path->private;
241
242 pr_err("z/VM *MONITOR system service disconnected with rc=%i\n",
243 ipuser[0]);
244 iucv_path_sever(path, NULL);
245 atomic_set(&monpriv->iucv_severed, 1);
246 wake_up(&mon_conn_wait_queue);
247 wake_up_interruptible(&mon_read_wait_queue);
248}
249
250static void mon_iucv_message_pending(struct iucv_path *path,
251 struct iucv_message *msg)
252{
253 struct mon_private *monpriv = path->private;
254
255 memcpy(&monpriv->msg_array[monpriv->write_index]->msg,
256 msg, sizeof(*msg));
257 if (atomic_inc_return(&monpriv->msglim_count) == MON_MSGLIM) {
258 pr_warn("The read queue for monitor data is full\n");
259 monpriv->msg_array[monpriv->write_index]->msglim_reached = 1;
260 }
261 monpriv->write_index = (monpriv->write_index + 1) % MON_MSGLIM;
262 atomic_inc(&monpriv->read_ready);
263 wake_up_interruptible(&mon_read_wait_queue);
264}
265
266static struct iucv_handler monreader_iucv_handler = {
267 .path_complete = mon_iucv_path_complete,
268 .path_severed = mon_iucv_path_severed,
269 .message_pending = mon_iucv_message_pending,
270};
271
272/******************************************************************************
273 * file operations *
274 *****************************************************************************/
275static int mon_open(struct inode *inode, struct file *filp)
276{
277 struct mon_private *monpriv;
278 int rc;
279
280 /*
281 * only one user allowed
282 */
283 rc = -EBUSY;
284 if (test_and_set_bit(MON_IN_USE, &mon_in_use))
285 goto out;
286
287 rc = -ENOMEM;
288 monpriv = mon_alloc_mem();
289 if (!monpriv)
290 goto out_use;
291
292 /*
293 * Connect to *MONITOR service
294 */
295 monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
296 if (!monpriv->path)
297 goto out_priv;
298 rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
299 MON_SERVICE, NULL, user_data_connect, monpriv);
300 if (rc) {
301 pr_err("Connecting to the z/VM *MONITOR system service "
302 "failed with rc=%i\n", rc);
303 rc = -EIO;
304 goto out_path;
305 }
306 /*
307 * Wait for connection confirmation
308 */
309 wait_event(mon_conn_wait_queue,
310 atomic_read(&monpriv->iucv_connected) ||
311 atomic_read(&monpriv->iucv_severed));
312 if (atomic_read(&monpriv->iucv_severed)) {
313 atomic_set(&monpriv->iucv_severed, 0);
314 atomic_set(&monpriv->iucv_connected, 0);
315 rc = -EIO;
316 goto out_path;
317 }
318 filp->private_data = monpriv;
319 return nonseekable_open(inode, filp);
320
321out_path:
322 iucv_path_free(monpriv->path);
323out_priv:
324 mon_free_mem(monpriv);
325out_use:
326 clear_bit(MON_IN_USE, &mon_in_use);
327out:
328 return rc;
329}
330
331static int mon_close(struct inode *inode, struct file *filp)
332{
333 int rc, i;
334 struct mon_private *monpriv = filp->private_data;
335
336 /*
337 * Close IUCV connection and unregister
338 */
339 if (monpriv->path) {
340 rc = iucv_path_sever(monpriv->path, user_data_sever);
341 if (rc)
342 pr_warn("Disconnecting the z/VM *MONITOR system service failed with rc=%i\n",
343 rc);
344 iucv_path_free(monpriv->path);
345 }
346
347 atomic_set(&monpriv->iucv_severed, 0);
348 atomic_set(&monpriv->iucv_connected, 0);
349 atomic_set(&monpriv->read_ready, 0);
350 atomic_set(&monpriv->msglim_count, 0);
351 monpriv->write_index = 0;
352 monpriv->read_index = 0;
353
354 for (i = 0; i < MON_MSGLIM; i++)
355 kfree(monpriv->msg_array[i]);
356 kfree(monpriv);
357 clear_bit(MON_IN_USE, &mon_in_use);
358 return 0;
359}
360
361static ssize_t mon_read(struct file *filp, char __user *data,
362 size_t count, loff_t *ppos)
363{
364 struct mon_private *monpriv = filp->private_data;
365 struct mon_msg *monmsg;
366 int ret;
367 u32 mce_start;
368
369 monmsg = mon_next_message(monpriv);
370 if (IS_ERR(monmsg))
371 return PTR_ERR(monmsg);
372
373 if (!monmsg) {
374 if (filp->f_flags & O_NONBLOCK)
375 return -EAGAIN;
376 ret = wait_event_interruptible(mon_read_wait_queue,
377 atomic_read(&monpriv->read_ready) ||
378 atomic_read(&monpriv->iucv_severed));
379 if (ret)
380 return ret;
381 if (unlikely(atomic_read(&monpriv->iucv_severed)))
382 return -EIO;
383 monmsg = monpriv->msg_array[monpriv->read_index];
384 }
385
386 if (!monmsg->pos)
387 monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset;
388 if (mon_check_mca(monmsg))
389 goto reply;
390
391 /* read monitor control element (12 bytes) first */
392 mce_start = mon_mca_start(monmsg) + monmsg->mca_offset;
393 if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) {
394 count = min(count, (size_t) mce_start + 12 - monmsg->pos);
395 ret = copy_to_user(data, __va(monmsg->pos), count);
396 if (ret)
397 return -EFAULT;
398 monmsg->pos += count;
399 if (monmsg->pos == mce_start + 12)
400 monmsg->pos = mon_rec_start(monmsg);
401 goto out_copy;
402 }
403
404 /* read records */
405 if (monmsg->pos <= mon_rec_end(monmsg)) {
406 count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos
407 + 1);
408 ret = copy_to_user(data, __va(monmsg->pos), count);
409 if (ret)
410 return -EFAULT;
411 monmsg->pos += count;
412 if (monmsg->pos > mon_rec_end(monmsg))
413 mon_next_mca(monmsg);
414 goto out_copy;
415 }
416reply:
417 ret = mon_send_reply(monmsg, monpriv);
418 return ret;
419
420out_copy:
421 *ppos += count;
422 return count;
423}
424
425static __poll_t mon_poll(struct file *filp, struct poll_table_struct *p)
426{
427 struct mon_private *monpriv = filp->private_data;
428
429 poll_wait(filp, &mon_read_wait_queue, p);
430 if (unlikely(atomic_read(&monpriv->iucv_severed)))
431 return EPOLLERR;
432 if (atomic_read(&monpriv->read_ready))
433 return EPOLLIN | EPOLLRDNORM;
434 return 0;
435}
436
437static const struct file_operations mon_fops = {
438 .owner = THIS_MODULE,
439 .open = &mon_open,
440 .release = &mon_close,
441 .read = &mon_read,
442 .poll = &mon_poll,
443 .llseek = noop_llseek,
444};
445
446static struct miscdevice mon_dev = {
447 .name = "monreader",
448 .fops = &mon_fops,
449 .minor = MISC_DYNAMIC_MINOR,
450};
451
452/******************************************************************************
453 * module init/exit *
454 *****************************************************************************/
455static int __init mon_init(void)
456{
457 int rc;
458
459 if (!MACHINE_IS_VM) {
460 pr_err("The z/VM *MONITOR record device driver cannot be "
461 "loaded without z/VM\n");
462 return -ENODEV;
463 }
464
465 /*
466 * Register with IUCV and connect to *MONITOR service
467 */
468 rc = iucv_register(&monreader_iucv_handler, 1);
469 if (rc) {
470 pr_err("The z/VM *MONITOR record device driver failed to "
471 "register with IUCV\n");
472 return rc;
473 }
474
475 rc = segment_type(mon_dcss_name);
476 if (rc < 0) {
477 segment_warning(rc, mon_dcss_name);
478 goto out_iucv;
479 }
480 if (rc != SEG_TYPE_SC) {
481 pr_err("The specified *MONITOR DCSS %s does not have the "
482 "required type SC\n", mon_dcss_name);
483 rc = -EINVAL;
484 goto out_iucv;
485 }
486
487 rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
488 &mon_dcss_start, &mon_dcss_end);
489 if (rc < 0) {
490 segment_warning(rc, mon_dcss_name);
491 rc = -EINVAL;
492 goto out_iucv;
493 }
494 dcss_mkname(mon_dcss_name, &user_data_connect[8]);
495
496 /*
497 * misc_register() has to be the last action in module_init(), because
498 * file operations will be available right after this.
499 */
500 rc = misc_register(&mon_dev);
501 if (rc < 0 )
502 goto out;
503 return 0;
504
505out:
506 segment_unload(mon_dcss_name);
507out_iucv:
508 iucv_unregister(&monreader_iucv_handler, 1);
509 return rc;
510}
511
512static void __exit mon_exit(void)
513{
514 segment_unload(mon_dcss_name);
515 misc_deregister(&mon_dev);
516 iucv_unregister(&monreader_iucv_handler, 1);
517 return;
518}
519
520
521module_init(mon_init);
522module_exit(mon_exit);
523
524module_param_string(mondcss, mon_dcss_name, 9, 0444);
525MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR "
526 "service, max. 8 chars. Default is MONDCSS");
527
528MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>");
529MODULE_DESCRIPTION("Character device driver for reading z/VM "
530 "monitor service records.");
531MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Character device driver for reading z/VM *MONITOR service records.
4 *
5 * Copyright IBM Corp. 2004, 2009
6 *
7 * Author: Gerald Schaefer <gerald.schaefer@de.ibm.com>
8 */
9
10#define KMSG_COMPONENT "monreader"
11#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
12
13#include <linux/module.h>
14#include <linux/moduleparam.h>
15#include <linux/init.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 <linux/slab.h>
26#include <net/iucv/iucv.h>
27#include <linux/uaccess.h>
28#include <asm/ebcdic.h>
29#include <asm/extmem.h>
30
31
32#define MON_COLLECT_SAMPLE 0x80
33#define MON_COLLECT_EVENT 0x40
34#define MON_SERVICE "*MONITOR"
35#define MON_IN_USE 0x01
36#define MON_MSGLIM 255
37
38static char mon_dcss_name[9] = "MONDCSS\0";
39
40struct mon_msg {
41 u32 pos;
42 u32 mca_offset;
43 struct iucv_message msg;
44 char msglim_reached;
45 char replied_msglim;
46};
47
48struct mon_private {
49 struct iucv_path *path;
50 struct mon_msg *msg_array[MON_MSGLIM];
51 unsigned int write_index;
52 unsigned int read_index;
53 atomic_t msglim_count;
54 atomic_t read_ready;
55 atomic_t iucv_connected;
56 atomic_t iucv_severed;
57};
58
59static unsigned long mon_in_use = 0;
60
61static unsigned long mon_dcss_start;
62static unsigned long mon_dcss_end;
63
64static DECLARE_WAIT_QUEUE_HEAD(mon_read_wait_queue);
65static DECLARE_WAIT_QUEUE_HEAD(mon_conn_wait_queue);
66
67static u8 user_data_connect[16] = {
68 /* Version code, must be 0x01 for shared mode */
69 0x01,
70 /* what to collect */
71 MON_COLLECT_SAMPLE | MON_COLLECT_EVENT,
72 /* DCSS name in EBCDIC, 8 bytes padded with blanks */
73 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
74 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
75};
76
77static u8 user_data_sever[16] = {
78 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
79 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
80};
81
82static struct device *monreader_device;
83
84/******************************************************************************
85 * helper functions *
86 *****************************************************************************/
87/*
88 * Create the 8 bytes EBCDIC DCSS segment name from
89 * an ASCII name, incl. padding
90 */
91static void dcss_mkname(char *ascii_name, char *ebcdic_name)
92{
93 int i;
94
95 for (i = 0; i < 8; i++) {
96 if (ascii_name[i] == '\0')
97 break;
98 ebcdic_name[i] = toupper(ascii_name[i]);
99 }
100 for (; i < 8; i++)
101 ebcdic_name[i] = ' ';
102 ASCEBC(ebcdic_name, 8);
103}
104
105static inline unsigned long mon_mca_start(struct mon_msg *monmsg)
106{
107 return *(u32 *) &monmsg->msg.rmmsg;
108}
109
110static inline unsigned long mon_mca_end(struct mon_msg *monmsg)
111{
112 return *(u32 *) &monmsg->msg.rmmsg[4];
113}
114
115static inline u8 mon_mca_type(struct mon_msg *monmsg, u8 index)
116{
117 return *((u8 *) mon_mca_start(monmsg) + monmsg->mca_offset + index);
118}
119
120static inline u32 mon_mca_size(struct mon_msg *monmsg)
121{
122 return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1;
123}
124
125static inline u32 mon_rec_start(struct mon_msg *monmsg)
126{
127 return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 4));
128}
129
130static inline u32 mon_rec_end(struct mon_msg *monmsg)
131{
132 return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 8));
133}
134
135static int mon_check_mca(struct mon_msg *monmsg)
136{
137 if ((mon_rec_end(monmsg) <= mon_rec_start(monmsg)) ||
138 (mon_rec_start(monmsg) < mon_dcss_start) ||
139 (mon_rec_end(monmsg) > mon_dcss_end) ||
140 (mon_mca_type(monmsg, 0) == 0) ||
141 (mon_mca_size(monmsg) % 12 != 0) ||
142 (mon_mca_end(monmsg) <= mon_mca_start(monmsg)) ||
143 (mon_mca_end(monmsg) > mon_dcss_end) ||
144 (mon_mca_start(monmsg) < mon_dcss_start) ||
145 ((mon_mca_type(monmsg, 1) == 0) && (mon_mca_type(monmsg, 2) == 0)))
146 return -EINVAL;
147 return 0;
148}
149
150static int mon_send_reply(struct mon_msg *monmsg,
151 struct mon_private *monpriv)
152{
153 int rc;
154
155 rc = iucv_message_reply(monpriv->path, &monmsg->msg,
156 IUCV_IPRMDATA, NULL, 0);
157 atomic_dec(&monpriv->msglim_count);
158 if (likely(!monmsg->msglim_reached)) {
159 monmsg->pos = 0;
160 monmsg->mca_offset = 0;
161 monpriv->read_index = (monpriv->read_index + 1) %
162 MON_MSGLIM;
163 atomic_dec(&monpriv->read_ready);
164 } else
165 monmsg->replied_msglim = 1;
166 if (rc) {
167 pr_err("Reading monitor data failed with rc=%i\n", rc);
168 return -EIO;
169 }
170 return 0;
171}
172
173static void mon_free_mem(struct mon_private *monpriv)
174{
175 int i;
176
177 for (i = 0; i < MON_MSGLIM; 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)
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)
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_warn("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 rc = -EBUSY;
287 if (test_and_set_bit(MON_IN_USE, &mon_in_use))
288 goto out;
289
290 rc = -ENOMEM;
291 monpriv = mon_alloc_mem();
292 if (!monpriv)
293 goto out_use;
294
295 /*
296 * Connect to *MONITOR service
297 */
298 monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
299 if (!monpriv->path)
300 goto out_priv;
301 rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
302 MON_SERVICE, NULL, user_data_connect, monpriv);
303 if (rc) {
304 pr_err("Connecting to the z/VM *MONITOR system service "
305 "failed with rc=%i\n", rc);
306 rc = -EIO;
307 goto out_path;
308 }
309 /*
310 * Wait for connection confirmation
311 */
312 wait_event(mon_conn_wait_queue,
313 atomic_read(&monpriv->iucv_connected) ||
314 atomic_read(&monpriv->iucv_severed));
315 if (atomic_read(&monpriv->iucv_severed)) {
316 atomic_set(&monpriv->iucv_severed, 0);
317 atomic_set(&monpriv->iucv_connected, 0);
318 rc = -EIO;
319 goto out_path;
320 }
321 filp->private_data = monpriv;
322 dev_set_drvdata(monreader_device, monpriv);
323 return nonseekable_open(inode, filp);
324
325out_path:
326 iucv_path_free(monpriv->path);
327out_priv:
328 mon_free_mem(monpriv);
329out_use:
330 clear_bit(MON_IN_USE, &mon_in_use);
331out:
332 return rc;
333}
334
335static int mon_close(struct inode *inode, struct file *filp)
336{
337 int rc, i;
338 struct mon_private *monpriv = filp->private_data;
339
340 /*
341 * Close IUCV connection and unregister
342 */
343 if (monpriv->path) {
344 rc = iucv_path_sever(monpriv->path, user_data_sever);
345 if (rc)
346 pr_warn("Disconnecting the z/VM *MONITOR system service failed with rc=%i\n",
347 rc);
348 iucv_path_free(monpriv->path);
349 }
350
351 atomic_set(&monpriv->iucv_severed, 0);
352 atomic_set(&monpriv->iucv_connected, 0);
353 atomic_set(&monpriv->read_ready, 0);
354 atomic_set(&monpriv->msglim_count, 0);
355 monpriv->write_index = 0;
356 monpriv->read_index = 0;
357 dev_set_drvdata(monreader_device, NULL);
358
359 for (i = 0; i < MON_MSGLIM; i++)
360 kfree(monpriv->msg_array[i]);
361 kfree(monpriv);
362 clear_bit(MON_IN_USE, &mon_in_use);
363 return 0;
364}
365
366static ssize_t mon_read(struct file *filp, char __user *data,
367 size_t count, loff_t *ppos)
368{
369 struct mon_private *monpriv = filp->private_data;
370 struct mon_msg *monmsg;
371 int ret;
372 u32 mce_start;
373
374 monmsg = mon_next_message(monpriv);
375 if (IS_ERR(monmsg))
376 return PTR_ERR(monmsg);
377
378 if (!monmsg) {
379 if (filp->f_flags & O_NONBLOCK)
380 return -EAGAIN;
381 ret = wait_event_interruptible(mon_read_wait_queue,
382 atomic_read(&monpriv->read_ready) ||
383 atomic_read(&monpriv->iucv_severed));
384 if (ret)
385 return ret;
386 if (unlikely(atomic_read(&monpriv->iucv_severed)))
387 return -EIO;
388 monmsg = monpriv->msg_array[monpriv->read_index];
389 }
390
391 if (!monmsg->pos)
392 monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset;
393 if (mon_check_mca(monmsg))
394 goto reply;
395
396 /* read monitor control element (12 bytes) first */
397 mce_start = mon_mca_start(monmsg) + monmsg->mca_offset;
398 if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) {
399 count = min(count, (size_t) mce_start + 12 - monmsg->pos);
400 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
401 count);
402 if (ret)
403 return -EFAULT;
404 monmsg->pos += count;
405 if (monmsg->pos == mce_start + 12)
406 monmsg->pos = mon_rec_start(monmsg);
407 goto out_copy;
408 }
409
410 /* read records */
411 if (monmsg->pos <= mon_rec_end(monmsg)) {
412 count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos
413 + 1);
414 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
415 count);
416 if (ret)
417 return -EFAULT;
418 monmsg->pos += count;
419 if (monmsg->pos > mon_rec_end(monmsg))
420 mon_next_mca(monmsg);
421 goto out_copy;
422 }
423reply:
424 ret = mon_send_reply(monmsg, monpriv);
425 return ret;
426
427out_copy:
428 *ppos += count;
429 return count;
430}
431
432static __poll_t mon_poll(struct file *filp, struct poll_table_struct *p)
433{
434 struct mon_private *monpriv = filp->private_data;
435
436 poll_wait(filp, &mon_read_wait_queue, p);
437 if (unlikely(atomic_read(&monpriv->iucv_severed)))
438 return EPOLLERR;
439 if (atomic_read(&monpriv->read_ready))
440 return EPOLLIN | EPOLLRDNORM;
441 return 0;
442}
443
444static const struct file_operations mon_fops = {
445 .owner = THIS_MODULE,
446 .open = &mon_open,
447 .release = &mon_close,
448 .read = &mon_read,
449 .poll = &mon_poll,
450 .llseek = noop_llseek,
451};
452
453static struct miscdevice mon_dev = {
454 .name = "monreader",
455 .fops = &mon_fops,
456 .minor = MISC_DYNAMIC_MINOR,
457};
458
459
460/******************************************************************************
461 * suspend / resume *
462 *****************************************************************************/
463static int monreader_freeze(struct device *dev)
464{
465 struct mon_private *monpriv = dev_get_drvdata(dev);
466 int rc;
467
468 if (!monpriv)
469 return 0;
470 if (monpriv->path) {
471 rc = iucv_path_sever(monpriv->path, user_data_sever);
472 if (rc)
473 pr_warn("Disconnecting the z/VM *MONITOR system service failed with rc=%i\n",
474 rc);
475 iucv_path_free(monpriv->path);
476 }
477 atomic_set(&monpriv->iucv_severed, 0);
478 atomic_set(&monpriv->iucv_connected, 0);
479 atomic_set(&monpriv->read_ready, 0);
480 atomic_set(&monpriv->msglim_count, 0);
481 monpriv->write_index = 0;
482 monpriv->read_index = 0;
483 monpriv->path = NULL;
484 return 0;
485}
486
487static int monreader_thaw(struct device *dev)
488{
489 struct mon_private *monpriv = dev_get_drvdata(dev);
490 int rc;
491
492 if (!monpriv)
493 return 0;
494 rc = -ENOMEM;
495 monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
496 if (!monpriv->path)
497 goto out;
498 rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
499 MON_SERVICE, NULL, user_data_connect, monpriv);
500 if (rc) {
501 pr_err("Connecting to the z/VM *MONITOR system service "
502 "failed with rc=%i\n", rc);
503 goto out_path;
504 }
505 wait_event(mon_conn_wait_queue,
506 atomic_read(&monpriv->iucv_connected) ||
507 atomic_read(&monpriv->iucv_severed));
508 if (atomic_read(&monpriv->iucv_severed))
509 goto out_path;
510 return 0;
511out_path:
512 rc = -EIO;
513 iucv_path_free(monpriv->path);
514 monpriv->path = NULL;
515out:
516 atomic_set(&monpriv->iucv_severed, 1);
517 return rc;
518}
519
520static int monreader_restore(struct device *dev)
521{
522 int rc;
523
524 segment_unload(mon_dcss_name);
525 rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
526 &mon_dcss_start, &mon_dcss_end);
527 if (rc < 0) {
528 segment_warning(rc, mon_dcss_name);
529 panic("fatal monreader resume error: no monitor dcss\n");
530 }
531 return monreader_thaw(dev);
532}
533
534static const struct dev_pm_ops monreader_pm_ops = {
535 .freeze = monreader_freeze,
536 .thaw = monreader_thaw,
537 .restore = monreader_restore,
538};
539
540static struct device_driver monreader_driver = {
541 .name = "monreader",
542 .bus = &iucv_bus,
543 .pm = &monreader_pm_ops,
544};
545
546
547/******************************************************************************
548 * module init/exit *
549 *****************************************************************************/
550static int __init mon_init(void)
551{
552 int rc;
553
554 if (!MACHINE_IS_VM) {
555 pr_err("The z/VM *MONITOR record device driver cannot be "
556 "loaded without z/VM\n");
557 return -ENODEV;
558 }
559
560 /*
561 * Register with IUCV and connect to *MONITOR service
562 */
563 rc = iucv_register(&monreader_iucv_handler, 1);
564 if (rc) {
565 pr_err("The z/VM *MONITOR record device driver failed to "
566 "register with IUCV\n");
567 return rc;
568 }
569
570 rc = driver_register(&monreader_driver);
571 if (rc)
572 goto out_iucv;
573 monreader_device = kzalloc(sizeof(struct device), GFP_KERNEL);
574 if (!monreader_device) {
575 rc = -ENOMEM;
576 goto out_driver;
577 }
578
579 dev_set_name(monreader_device, "monreader-dev");
580 monreader_device->bus = &iucv_bus;
581 monreader_device->parent = iucv_root;
582 monreader_device->driver = &monreader_driver;
583 monreader_device->release = (void (*)(struct device *))kfree;
584 rc = device_register(monreader_device);
585 if (rc) {
586 put_device(monreader_device);
587 goto out_driver;
588 }
589
590 rc = segment_type(mon_dcss_name);
591 if (rc < 0) {
592 segment_warning(rc, mon_dcss_name);
593 goto out_device;
594 }
595 if (rc != SEG_TYPE_SC) {
596 pr_err("The specified *MONITOR DCSS %s does not have the "
597 "required type SC\n", mon_dcss_name);
598 rc = -EINVAL;
599 goto out_device;
600 }
601
602 rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
603 &mon_dcss_start, &mon_dcss_end);
604 if (rc < 0) {
605 segment_warning(rc, mon_dcss_name);
606 rc = -EINVAL;
607 goto out_device;
608 }
609 dcss_mkname(mon_dcss_name, &user_data_connect[8]);
610
611 /*
612 * misc_register() has to be the last action in module_init(), because
613 * file operations will be available right after this.
614 */
615 rc = misc_register(&mon_dev);
616 if (rc < 0 )
617 goto out;
618 return 0;
619
620out:
621 segment_unload(mon_dcss_name);
622out_device:
623 device_unregister(monreader_device);
624out_driver:
625 driver_unregister(&monreader_driver);
626out_iucv:
627 iucv_unregister(&monreader_iucv_handler, 1);
628 return rc;
629}
630
631static void __exit mon_exit(void)
632{
633 segment_unload(mon_dcss_name);
634 misc_deregister(&mon_dev);
635 device_unregister(monreader_device);
636 driver_unregister(&monreader_driver);
637 iucv_unregister(&monreader_iucv_handler, 1);
638 return;
639}
640
641
642module_init(mon_init);
643module_exit(mon_exit);
644
645module_param_string(mondcss, mon_dcss_name, 9, 0444);
646MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR "
647 "service, max. 8 chars. Default is MONDCSS");
648
649MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>");
650MODULE_DESCRIPTION("Character device driver for reading z/VM "
651 "monitor service records.");
652MODULE_LICENSE("GPL");