1/*
2 * Character device driver for writing z/VM *MONITOR service records.
3 *
4 * Copyright IBM Corp. 2006, 2009
5 *
6 * Author(s): Melissa Howland <Melissa.Howland@us.ibm.com>
7 */
8
9#define KMSG_COMPONENT "monwriter"
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/errno.h>
16#include <linux/types.h>
17#include <linux/kernel.h>
18#include <linux/miscdevice.h>
19#include <linux/ctype.h>
20#include <linux/poll.h>
21#include <linux/mutex.h>
22#include <linux/platform_device.h>
23#include <linux/slab.h>
24#include <asm/uaccess.h>
25#include <asm/ebcdic.h>
26#include <asm/io.h>
27#include <asm/appldata.h>
28#include <asm/monwriter.h>
29
30#define MONWRITE_MAX_DATALEN	4010
31
32static int mon_max_bufs = 255;
33static int mon_buf_count;
34
35struct mon_buf {
36	struct list_head list;
37	struct monwrite_hdr hdr;
38	int diag_done;
39	char *data;
40};
41
42static LIST_HEAD(mon_priv_list);
43
44struct mon_private {
45	struct list_head priv_list;
46	struct list_head list;
47	struct monwrite_hdr hdr;
48	size_t hdr_to_read;
49	size_t data_to_read;
50	struct mon_buf *current_buf;
51	struct mutex thread_mutex;
52};
53
54/*
55 * helper functions
56 */
57
58static int monwrite_diag(struct monwrite_hdr *myhdr, char *buffer, int fcn)
59{
60	struct appldata_product_id id;
61	int rc;
62
63	strncpy(id.prod_nr, "LNXAPPL", 7);
64	id.prod_fn = myhdr->applid;
65	id.record_nr = myhdr->record_num;
66	id.version_nr = myhdr->version;
67	id.release_nr = myhdr->release;
68	id.mod_lvl = myhdr->mod_level;
69	rc = appldata_asm(&id, fcn, (void *) buffer, myhdr->datalen);
70	if (rc <= 0)
71		return rc;
72	pr_err("Writing monitor data failed with rc=%i\n", rc);
73	if (rc == 5)
74		return -EPERM;
75	return -EINVAL;
76}
77
78static struct mon_buf *monwrite_find_hdr(struct mon_private *monpriv,
79					 struct monwrite_hdr *monhdr)
80{
81	struct mon_buf *entry, *next;
82
83	list_for_each_entry_safe(entry, next, &monpriv->list, list)
84		if ((entry->hdr.mon_function == monhdr->mon_function ||
85		     monhdr->mon_function == MONWRITE_STOP_INTERVAL) &&
86		    entry->hdr.applid == monhdr->applid &&
87		    entry->hdr.record_num == monhdr->record_num &&
88		    entry->hdr.version == monhdr->version &&
89		    entry->hdr.release == monhdr->release &&
90		    entry->hdr.mod_level == monhdr->mod_level)
91			return entry;
92
93	return NULL;
94}
95
96static int monwrite_new_hdr(struct mon_private *monpriv)
97{
98	struct monwrite_hdr *monhdr = &monpriv->hdr;
99	struct mon_buf *monbuf;
100	int rc = 0;
101
102	if (monhdr->datalen > MONWRITE_MAX_DATALEN ||
103	    monhdr->mon_function > MONWRITE_START_CONFIG ||
104	    monhdr->hdrlen != sizeof(struct monwrite_hdr))
105		return -EINVAL;
106	monbuf = NULL;
107	if (monhdr->mon_function != MONWRITE_GEN_EVENT)
108		monbuf = monwrite_find_hdr(monpriv, monhdr);
109	if (monbuf) {
110		if (monhdr->mon_function == MONWRITE_STOP_INTERVAL) {
111			monhdr->datalen = monbuf->hdr.datalen;
112			rc = monwrite_diag(monhdr, monbuf->data,
113					   APPLDATA_STOP_REC);
114			list_del(&monbuf->list);
115			mon_buf_count--;
116			kfree(monbuf->data);
117			kfree(monbuf);
118			monbuf = NULL;
119		}
120	} else if (monhdr->mon_function != MONWRITE_STOP_INTERVAL) {
121		if (mon_buf_count >= mon_max_bufs)
122			return -ENOSPC;
123		monbuf = kzalloc(sizeof(struct mon_buf), GFP_KERNEL);
124		if (!monbuf)
125			return -ENOMEM;
126		monbuf->data = kzalloc(monhdr->datalen,
127				       GFP_KERNEL | GFP_DMA);
128		if (!monbuf->data) {
129			kfree(monbuf);
130			return -ENOMEM;
131		}
132		monbuf->hdr = *monhdr;
133		list_add_tail(&monbuf->list, &monpriv->list);
134		if (monhdr->mon_function != MONWRITE_GEN_EVENT)
135			mon_buf_count++;
136	}
137	monpriv->current_buf = monbuf;
138	return rc;
139}
140
141static int monwrite_new_data(struct mon_private *monpriv)
142{
143	struct monwrite_hdr *monhdr = &monpriv->hdr;
144	struct mon_buf *monbuf = monpriv->current_buf;
145	int rc = 0;
146
147	switch (monhdr->mon_function) {
148	case MONWRITE_START_INTERVAL:
149		if (!monbuf->diag_done) {
150			rc = monwrite_diag(monhdr, monbuf->data,
151					   APPLDATA_START_INTERVAL_REC);
152			monbuf->diag_done = 1;
153		}
154		break;
155	case MONWRITE_START_CONFIG:
156		if (!monbuf->diag_done) {
157			rc = monwrite_diag(monhdr, monbuf->data,
158					   APPLDATA_START_CONFIG_REC);
159			monbuf->diag_done = 1;
160		}
161		break;
162	case MONWRITE_GEN_EVENT:
163		rc = monwrite_diag(monhdr, monbuf->data,
164				   APPLDATA_GEN_EVENT_REC);
165		list_del(&monpriv->current_buf->list);
166		kfree(monpriv->current_buf->data);
167		kfree(monpriv->current_buf);
168		monpriv->current_buf = NULL;
169		break;
170	default:
171		/* monhdr->mon_function is checked in monwrite_new_hdr */
172		BUG();
173	}
174	return rc;
175}
176
177/*
178 * file operations
179 */
180
181static int monwrite_open(struct inode *inode, struct file *filp)
182{
183	struct mon_private *monpriv;
184
185	monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
186	if (!monpriv)
187		return -ENOMEM;
188	INIT_LIST_HEAD(&monpriv->list);
189	monpriv->hdr_to_read = sizeof(monpriv->hdr);
190	mutex_init(&monpriv->thread_mutex);
191	filp->private_data = monpriv;
192	list_add_tail(&monpriv->priv_list, &mon_priv_list);
193	return nonseekable_open(inode, filp);
194}
195
196static int monwrite_close(struct inode *inode, struct file *filp)
197{
198	struct mon_private *monpriv = filp->private_data;
199	struct mon_buf *entry, *next;
200
201	list_for_each_entry_safe(entry, next, &monpriv->list, list) {
202		if (entry->hdr.mon_function != MONWRITE_GEN_EVENT)
203			monwrite_diag(&entry->hdr, entry->data,
204				      APPLDATA_STOP_REC);
205		mon_buf_count--;
206		list_del(&entry->list);
207		kfree(entry->data);
208		kfree(entry);
209	}
210	list_del(&monpriv->priv_list);
211	kfree(monpriv);
212	return 0;
213}
214
215static ssize_t monwrite_write(struct file *filp, const char __user *data,
216			      size_t count, loff_t *ppos)
217{
218	struct mon_private *monpriv = filp->private_data;
219	size_t len, written;
220	void *to;
221	int rc;
222
223	mutex_lock(&monpriv->thread_mutex);
224	for (written = 0; written < count; ) {
225		if (monpriv->hdr_to_read) {
226			len = min(count - written, monpriv->hdr_to_read);
227			to = (char *) &monpriv->hdr +
228				sizeof(monpriv->hdr) - monpriv->hdr_to_read;
229			if (copy_from_user(to, data + written, len)) {
230				rc = -EFAULT;
231				goto out_error;
232			}
233			monpriv->hdr_to_read -= len;
234			written += len;
235			if (monpriv->hdr_to_read > 0)
236				continue;
237			rc = monwrite_new_hdr(monpriv);
238			if (rc)
239				goto out_error;
240			monpriv->data_to_read = monpriv->current_buf ?
241				monpriv->current_buf->hdr.datalen : 0;
242		}
243
244		if (monpriv->data_to_read) {
245			len = min(count - written, monpriv->data_to_read);
246			to = monpriv->current_buf->data +
247				monpriv->hdr.datalen - monpriv->data_to_read;
248			if (copy_from_user(to, data + written, len)) {
249				rc = -EFAULT;
250				goto out_error;
251			}
252			monpriv->data_to_read -= len;
253			written += len;
254			if (monpriv->data_to_read > 0)
255				continue;
256			rc = monwrite_new_data(monpriv);
257			if (rc)
258				goto out_error;
259		}
260		monpriv->hdr_to_read = sizeof(monpriv->hdr);
261	}
262	mutex_unlock(&monpriv->thread_mutex);
263	return written;
264
265out_error:
266	monpriv->data_to_read = 0;
267	monpriv->hdr_to_read = sizeof(struct monwrite_hdr);
268	mutex_unlock(&monpriv->thread_mutex);
269	return rc;
270}
271
272static const struct file_operations monwrite_fops = {
273	.owner	 = THIS_MODULE,
274	.open	 = &monwrite_open,
275	.release = &monwrite_close,
276	.write	 = &monwrite_write,
277	.llseek  = noop_llseek,
278};
279
280static struct miscdevice mon_dev = {
281	.name	= "monwriter",
282	.fops	= &monwrite_fops,
283	.minor	= MISC_DYNAMIC_MINOR,
284};
285
286/*
287 * suspend/resume
288 */
289
290static int monwriter_freeze(struct device *dev)
291{
292	struct mon_private *monpriv;
293	struct mon_buf *monbuf;
294
295	list_for_each_entry(monpriv, &mon_priv_list, priv_list) {
296		list_for_each_entry(monbuf, &monpriv->list, list) {
297			if (monbuf->hdr.mon_function != MONWRITE_GEN_EVENT)
298				monwrite_diag(&monbuf->hdr, monbuf->data,
299					      APPLDATA_STOP_REC);
300		}
301	}
302	return 0;
303}
304
305static int monwriter_restore(struct device *dev)
306{
307	struct mon_private *monpriv;
308	struct mon_buf *monbuf;
309
310	list_for_each_entry(monpriv, &mon_priv_list, priv_list) {
311		list_for_each_entry(monbuf, &monpriv->list, list) {
312			if (monbuf->hdr.mon_function == MONWRITE_START_INTERVAL)
313				monwrite_diag(&monbuf->hdr, monbuf->data,
314					      APPLDATA_START_INTERVAL_REC);
315			if (monbuf->hdr.mon_function == MONWRITE_START_CONFIG)
316				monwrite_diag(&monbuf->hdr, monbuf->data,
317					      APPLDATA_START_CONFIG_REC);
318		}
319	}
320	return 0;
321}
322
323static int monwriter_thaw(struct device *dev)
324{
325	return monwriter_restore(dev);
326}
327
328static const struct dev_pm_ops monwriter_pm_ops = {
329	.freeze		= monwriter_freeze,
330	.thaw		= monwriter_thaw,
331	.restore	= monwriter_restore,
332};
333
334static struct platform_driver monwriter_pdrv = {
335	.driver = {
336		.name	= "monwriter",
337		.pm	= &monwriter_pm_ops,
338	},
339};
340
341static struct platform_device *monwriter_pdev;
342
343/*
344 * module init/exit
345 */
346
347static int __init mon_init(void)
348{
349	int rc;
350
351	if (!MACHINE_IS_VM)
352		return -ENODEV;
353
354	rc = platform_driver_register(&monwriter_pdrv);
355	if (rc)
356		return rc;
357
358	monwriter_pdev = platform_device_register_simple("monwriter", -1, NULL,
359							0);
360	if (IS_ERR(monwriter_pdev)) {
361		rc = PTR_ERR(monwriter_pdev);
362		goto out_driver;
363	}
364
365	/*
366	 * misc_register() has to be the last action in module_init(), because
367	 * file operations will be available right after this.
368	 */
369	rc = misc_register(&mon_dev);
370	if (rc)
371		goto out_device;
372	return 0;
373
374out_device:
375	platform_device_unregister(monwriter_pdev);
376out_driver:
377	platform_driver_unregister(&monwriter_pdrv);
378	return rc;
379}
380
381static void __exit mon_exit(void)
382{
383	misc_deregister(&mon_dev);
384	platform_device_unregister(monwriter_pdev);
385	platform_driver_unregister(&monwriter_pdrv);
386}
387
388module_init(mon_init);
389module_exit(mon_exit);
390
391module_param_named(max_bufs, mon_max_bufs, int, 0644);
392MODULE_PARM_DESC(max_bufs, "Maximum number of sample monitor data buffers "
393		 "that can be active at one time");
394
395MODULE_AUTHOR("Melissa Howland <Melissa.Howland@us.ibm.com>");
396MODULE_DESCRIPTION("Character device driver for writing z/VM "
397		   "APPLDATA monitor records.");
398MODULE_LICENSE("GPL");
399