1/*
2 * drivers/s390/char/monwriter.c
3 *
4 * Character device driver for writing z/VM *MONITOR service records.
5 *
6 * Copyright (C) IBM Corp. 2006
7 *
8 * Author(s): Melissa Howland <Melissa.Howland@us.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/poll.h>
20#include <asm/uaccess.h>
21#include <asm/ebcdic.h>
22#include <asm/io.h>
23#include <asm/appldata.h>
24#include <asm/monwriter.h>
25
26#define MONWRITE_MAX_DATALEN	4010
27
28static int mon_max_bufs = 255;
29static int mon_buf_count;
30
31struct mon_buf {
32	struct list_head list;
33	struct monwrite_hdr hdr;
34	int diag_done;
35	char *data;
36};
37
38struct mon_private {
39	struct list_head list;
40	struct monwrite_hdr hdr;
41	size_t hdr_to_read;
42	size_t data_to_read;
43	struct mon_buf *current_buf;
44};
45
46/*
47 * helper functions
48 */
49
50static int monwrite_diag(struct monwrite_hdr *myhdr, char *buffer, int fcn)
51{
52	struct appldata_product_id id;
53	int rc;
54
55	strcpy(id.prod_nr, "LNXAPPL");
56	id.prod_fn = myhdr->applid;
57	id.record_nr = myhdr->record_num;
58	id.version_nr = myhdr->version;
59	id.release_nr = myhdr->release;
60	id.mod_lvl = myhdr->mod_level;
61	rc = appldata_asm(&id, fcn, (void *) buffer, myhdr->datalen);
62	if (rc <= 0)
63		return rc;
64	if (rc == 5)
65		return -EPERM;
66	printk("DIAG X'DC' error with return code: %i\n", rc);
67	return -EINVAL;
68}
69
70static struct mon_buf *monwrite_find_hdr(struct mon_private *monpriv,
71					 struct monwrite_hdr *monhdr)
72{
73	struct mon_buf *entry, *next;
74
75	list_for_each_entry_safe(entry, next, &monpriv->list, list)
76		if ((entry->hdr.mon_function == monhdr->mon_function ||
77		     monhdr->mon_function == MONWRITE_STOP_INTERVAL) &&
78		    entry->hdr.applid == monhdr->applid &&
79		    entry->hdr.record_num == monhdr->record_num &&
80		    entry->hdr.version == monhdr->version &&
81		    entry->hdr.release == monhdr->release &&
82		    entry->hdr.mod_level == monhdr->mod_level)
83			return entry;
84
85	return NULL;
86}
87
88static int monwrite_new_hdr(struct mon_private *monpriv)
89{
90	struct monwrite_hdr *monhdr = &monpriv->hdr;
91	struct mon_buf *monbuf;
92	int rc;
93
94	if (monhdr->datalen > MONWRITE_MAX_DATALEN ||
95	    monhdr->mon_function > MONWRITE_START_CONFIG ||
96	    monhdr->hdrlen != sizeof(struct monwrite_hdr))
97		return -EINVAL;
98	monbuf = NULL;
99	if (monhdr->mon_function != MONWRITE_GEN_EVENT)
100		monbuf = monwrite_find_hdr(monpriv, monhdr);
101	if (monbuf) {
102		if (monhdr->mon_function == MONWRITE_STOP_INTERVAL) {
103			monhdr->datalen = monbuf->hdr.datalen;
104			rc = monwrite_diag(monhdr, monbuf->data,
105					   APPLDATA_STOP_REC);
106			list_del(&monbuf->list);
107			mon_buf_count--;
108			kfree(monbuf->data);
109			kfree(monbuf);
110			monbuf = NULL;
111		}
112	} else if (monhdr->mon_function != MONWRITE_STOP_INTERVAL) {
113		if (mon_buf_count >= mon_max_bufs)
114			return -ENOSPC;
115		monbuf = kzalloc(sizeof(struct mon_buf), GFP_KERNEL);
116		if (!monbuf)
117			return -ENOMEM;
118		monbuf->data = kzalloc(monhdr->datalen,
119				       GFP_KERNEL | GFP_DMA);
120		if (!monbuf->data) {
121			kfree(monbuf);
122			return -ENOMEM;
123		}
124		monbuf->hdr = *monhdr;
125		list_add_tail(&monbuf->list, &monpriv->list);
126		if (monhdr->mon_function != MONWRITE_GEN_EVENT)
127			mon_buf_count++;
128	}
129	monpriv->current_buf = monbuf;
130	return 0;
131}
132
133static int monwrite_new_data(struct mon_private *monpriv)
134{
135	struct monwrite_hdr *monhdr = &monpriv->hdr;
136	struct mon_buf *monbuf = monpriv->current_buf;
137	int rc = 0;
138
139	switch (monhdr->mon_function) {
140	case MONWRITE_START_INTERVAL:
141		if (!monbuf->diag_done) {
142			rc = monwrite_diag(monhdr, monbuf->data,
143					   APPLDATA_START_INTERVAL_REC);
144			monbuf->diag_done = 1;
145		}
146		break;
147	case MONWRITE_START_CONFIG:
148		if (!monbuf->diag_done) {
149			rc = monwrite_diag(monhdr, monbuf->data,
150					   APPLDATA_START_CONFIG_REC);
151			monbuf->diag_done = 1;
152		}
153		break;
154	case MONWRITE_GEN_EVENT:
155		rc = monwrite_diag(monhdr, monbuf->data,
156				   APPLDATA_GEN_EVENT_REC);
157		list_del(&monpriv->current_buf->list);
158		kfree(monpriv->current_buf->data);
159		kfree(monpriv->current_buf);
160		monpriv->current_buf = NULL;
161		break;
162	default:
163		/* monhdr->mon_function is checked in monwrite_new_hdr */
164		BUG();
165	}
166	return rc;
167}
168
169/*
170 * file operations
171 */
172
173static int monwrite_open(struct inode *inode, struct file *filp)
174{
175	struct mon_private *monpriv;
176
177	monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
178	if (!monpriv)
179		return -ENOMEM;
180	INIT_LIST_HEAD(&monpriv->list);
181	monpriv->hdr_to_read = sizeof(monpriv->hdr);
182	filp->private_data = monpriv;
183	return nonseekable_open(inode, filp);
184}
185
186static int monwrite_close(struct inode *inode, struct file *filp)
187{
188	struct mon_private *monpriv = filp->private_data;
189	struct mon_buf *entry, *next;
190
191	list_for_each_entry_safe(entry, next, &monpriv->list, list) {
192		if (entry->hdr.mon_function != MONWRITE_GEN_EVENT)
193			monwrite_diag(&entry->hdr, entry->data,
194				      APPLDATA_STOP_REC);
195		mon_buf_count--;
196		list_del(&entry->list);
197		kfree(entry->data);
198		kfree(entry);
199	}
200	kfree(monpriv);
201	return 0;
202}
203
204static ssize_t monwrite_write(struct file *filp, const char __user *data,
205			      size_t count, loff_t *ppos)
206{
207	struct mon_private *monpriv = filp->private_data;
208	size_t len, written;
209	void *to;
210	int rc;
211
212	for (written = 0; written < count; ) {
213		if (monpriv->hdr_to_read) {
214			len = min(count - written, monpriv->hdr_to_read);
215			to = (char *) &monpriv->hdr +
216				sizeof(monpriv->hdr) - monpriv->hdr_to_read;
217			if (copy_from_user(to, data + written, len)) {
218				rc = -EFAULT;
219				goto out_error;
220			}
221			monpriv->hdr_to_read -= len;
222			written += len;
223			if (monpriv->hdr_to_read > 0)
224				continue;
225			rc = monwrite_new_hdr(monpriv);
226			if (rc)
227				goto out_error;
228			monpriv->data_to_read = monpriv->current_buf ?
229				monpriv->current_buf->hdr.datalen : 0;
230		}
231
232		if (monpriv->data_to_read) {
233			len = min(count - written, monpriv->data_to_read);
234			to = monpriv->current_buf->data +
235				monpriv->hdr.datalen - monpriv->data_to_read;
236			if (copy_from_user(to, data + written, len)) {
237				rc = -EFAULT;
238				goto out_error;
239			}
240			monpriv->data_to_read -= len;
241			written += len;
242			if (monpriv->data_to_read > 0)
243				continue;
244			rc = monwrite_new_data(monpriv);
245			if (rc)
246				goto out_error;
247		}
248		monpriv->hdr_to_read = sizeof(monpriv->hdr);
249	}
250	return written;
251
252out_error:
253	monpriv->data_to_read = 0;
254	monpriv->hdr_to_read = sizeof(struct monwrite_hdr);
255	return rc;
256}
257
258static const struct file_operations monwrite_fops = {
259	.owner	 = THIS_MODULE,
260	.open	 = &monwrite_open,
261	.release = &monwrite_close,
262	.write	 = &monwrite_write,
263};
264
265static struct miscdevice mon_dev = {
266	.name	= "monwriter",
267	.fops	= &monwrite_fops,
268	.minor	= MISC_DYNAMIC_MINOR,
269};
270
271/*
272 * module init/exit
273 */
274
275static int __init mon_init(void)
276{
277	if (MACHINE_IS_VM)
278		return misc_register(&mon_dev);
279	else
280		return -ENODEV;
281}
282
283static void __exit mon_exit(void)
284{
285	WARN_ON(misc_deregister(&mon_dev) != 0);
286}
287
288module_init(mon_init);
289module_exit(mon_exit);
290
291module_param_named(max_bufs, mon_max_bufs, int, 0644);
292MODULE_PARM_DESC(max_bufs, "Maximum number of sample monitor data buffers"
293		 "that can be active at one time");
294
295MODULE_AUTHOR("Melissa Howland <Melissa.Howland@us.ibm.com>");
296MODULE_DESCRIPTION("Character device driver for writing z/VM "
297		   "APPLDATA monitor records.");
298MODULE_LICENSE("GPL");
299