1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Character device driver for writing z/VM *MONITOR service records.
4  *
5  * Copyright IBM Corp. 2006, 2009
6  *
7  * Author(s): Melissa Howland <Melissa.Howland@us.ibm.com>
8  */
9 
10 #define KMSG_COMPONENT "monwriter"
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/poll.h>
22 #include <linux/mutex.h>
23 #include <linux/slab.h>
24 #include <linux/uaccess.h>
25 #include <linux/io.h>
26 #include <asm/machine.h>
27 #include <asm/ebcdic.h>
28 #include <asm/appldata.h>
29 #include <asm/monwriter.h>
30 
31 #define MONWRITE_MAX_DATALEN	4010
32 
33 static int mon_max_bufs = 255;
34 static int mon_buf_count;
35 
36 struct mon_buf {
37 	struct list_head list;
38 	struct monwrite_hdr hdr;
39 	int diag_done;
40 	char *data;
41 };
42 
43 struct mon_private {
44 	struct list_head list;
45 	struct monwrite_hdr hdr;
46 	size_t hdr_to_read;
47 	size_t data_to_read;
48 	struct mon_buf *current_buf;
49 	struct mutex thread_mutex;
50 };
51 
52 /*
53  * helper functions
54  */
55 
56 static int monwrite_diag(struct monwrite_hdr *myhdr, char *buffer, int fcn)
57 {
58 	struct appldata_parameter_list *parm_list;
59 	struct appldata_product_id *id;
60 	int rc;
61 
62 	id = kmalloc(sizeof(*id), GFP_KERNEL);
63 	parm_list = kmalloc(sizeof(*parm_list), GFP_KERNEL);
64 	rc = -ENOMEM;
65 	if (!id || !parm_list)
66 		goto out;
67 	memcpy(id->prod_nr, "LNXAPPL", 7);
68 	id->prod_fn = myhdr->applid;
69 	id->record_nr = myhdr->record_num;
70 	id->version_nr = myhdr->version;
71 	id->release_nr = myhdr->release;
72 	id->mod_lvl = myhdr->mod_level;
73 	rc = appldata_asm(parm_list, id, fcn,
74 			  (void *) buffer, myhdr->datalen);
75 	if (rc <= 0)
76 		goto out;
77 	pr_err("Writing monitor data failed with rc=%i\n", rc);
78 	rc = (rc == 5) ? -EPERM : -EINVAL;
79 out:
80 	kfree(id);
81 	kfree(parm_list);
82 	return rc;
83 }
84 
85 static struct mon_buf *monwrite_find_hdr(struct mon_private *monpriv,
86 					 struct monwrite_hdr *monhdr)
87 {
88 	struct mon_buf *entry, *next;
89 
90 	list_for_each_entry_safe(entry, next, &monpriv->list, list)
91 		if ((entry->hdr.mon_function == monhdr->mon_function ||
92 		     monhdr->mon_function == MONWRITE_STOP_INTERVAL) &&
93 		    entry->hdr.applid == monhdr->applid &&
94 		    entry->hdr.record_num == monhdr->record_num &&
95 		    entry->hdr.version == monhdr->version &&
96 		    entry->hdr.release == monhdr->release &&
97 		    entry->hdr.mod_level == monhdr->mod_level)
98 			return entry;
99 
100 	return NULL;
101 }
102 
103 static int monwrite_new_hdr(struct mon_private *monpriv)
104 {
105 	struct monwrite_hdr *monhdr = &monpriv->hdr;
106 	struct mon_buf *monbuf;
107 	int rc = 0;
108 
109 	if (monhdr->datalen > MONWRITE_MAX_DATALEN ||
110 	    monhdr->mon_function > MONWRITE_START_CONFIG ||
111 	    monhdr->hdrlen != sizeof(struct monwrite_hdr))
112 		return -EINVAL;
113 	monbuf = NULL;
114 	if (monhdr->mon_function != MONWRITE_GEN_EVENT)
115 		monbuf = monwrite_find_hdr(monpriv, monhdr);
116 	if (monbuf) {
117 		if (monhdr->mon_function == MONWRITE_STOP_INTERVAL) {
118 			monhdr->datalen = monbuf->hdr.datalen;
119 			rc = monwrite_diag(monhdr, monbuf->data,
120 					   APPLDATA_STOP_REC);
121 			list_del(&monbuf->list);
122 			mon_buf_count--;
123 			kfree(monbuf->data);
124 			kfree(monbuf);
125 			monbuf = NULL;
126 		}
127 	} else if (monhdr->mon_function != MONWRITE_STOP_INTERVAL) {
128 		if (mon_buf_count >= mon_max_bufs)
129 			return -ENOSPC;
130 		monbuf = kzalloc(sizeof(struct mon_buf), GFP_KERNEL);
131 		if (!monbuf)
132 			return -ENOMEM;
133 		monbuf->data = kzalloc(monhdr->datalen,
134 				       GFP_KERNEL | GFP_DMA);
135 		if (!monbuf->data) {
136 			kfree(monbuf);
137 			return -ENOMEM;
138 		}
139 		monbuf->hdr = *monhdr;
140 		list_add_tail(&monbuf->list, &monpriv->list);
141 		if (monhdr->mon_function != MONWRITE_GEN_EVENT)
142 			mon_buf_count++;
143 	}
144 	monpriv->current_buf = monbuf;
145 	return rc;
146 }
147 
148 static int monwrite_new_data(struct mon_private *monpriv)
149 {
150 	struct monwrite_hdr *monhdr = &monpriv->hdr;
151 	struct mon_buf *monbuf = monpriv->current_buf;
152 	int rc = 0;
153 
154 	switch (monhdr->mon_function) {
155 	case MONWRITE_START_INTERVAL:
156 		if (!monbuf->diag_done) {
157 			rc = monwrite_diag(monhdr, monbuf->data,
158 					   APPLDATA_START_INTERVAL_REC);
159 			monbuf->diag_done = 1;
160 		}
161 		break;
162 	case MONWRITE_START_CONFIG:
163 		if (!monbuf->diag_done) {
164 			rc = monwrite_diag(monhdr, monbuf->data,
165 					   APPLDATA_START_CONFIG_REC);
166 			monbuf->diag_done = 1;
167 		}
168 		break;
169 	case MONWRITE_GEN_EVENT:
170 		rc = monwrite_diag(monhdr, monbuf->data,
171 				   APPLDATA_GEN_EVENT_REC);
172 		list_del(&monpriv->current_buf->list);
173 		kfree(monpriv->current_buf->data);
174 		kfree(monpriv->current_buf);
175 		monpriv->current_buf = NULL;
176 		break;
177 	default:
178 		/* monhdr->mon_function is checked in monwrite_new_hdr */
179 		BUG();
180 	}
181 	return rc;
182 }
183 
184 /*
185  * file operations
186  */
187 
188 static int monwrite_open(struct inode *inode, struct file *filp)
189 {
190 	struct mon_private *monpriv;
191 
192 	monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
193 	if (!monpriv)
194 		return -ENOMEM;
195 	INIT_LIST_HEAD(&monpriv->list);
196 	monpriv->hdr_to_read = sizeof(monpriv->hdr);
197 	mutex_init(&monpriv->thread_mutex);
198 	filp->private_data = monpriv;
199 	return nonseekable_open(inode, filp);
200 }
201 
202 static int monwrite_close(struct inode *inode, struct file *filp)
203 {
204 	struct mon_private *monpriv = filp->private_data;
205 	struct mon_buf *entry, *next;
206 
207 	list_for_each_entry_safe(entry, next, &monpriv->list, list) {
208 		if (entry->hdr.mon_function != MONWRITE_GEN_EVENT)
209 			monwrite_diag(&entry->hdr, entry->data,
210 				      APPLDATA_STOP_REC);
211 		mon_buf_count--;
212 		list_del(&entry->list);
213 		kfree(entry->data);
214 		kfree(entry);
215 	}
216 	kfree(monpriv);
217 	return 0;
218 }
219 
220 static ssize_t monwrite_write(struct file *filp, const char __user *data,
221 			      size_t count, loff_t *ppos)
222 {
223 	struct mon_private *monpriv = filp->private_data;
224 	size_t len, written;
225 	void *to;
226 	int rc;
227 
228 	mutex_lock(&monpriv->thread_mutex);
229 	for (written = 0; written < count; ) {
230 		if (monpriv->hdr_to_read) {
231 			len = min(count - written, monpriv->hdr_to_read);
232 			to = (char *) &monpriv->hdr +
233 				sizeof(monpriv->hdr) - monpriv->hdr_to_read;
234 			if (copy_from_user(to, data + written, len)) {
235 				rc = -EFAULT;
236 				goto out_error;
237 			}
238 			monpriv->hdr_to_read -= len;
239 			written += len;
240 			if (monpriv->hdr_to_read > 0)
241 				continue;
242 			rc = monwrite_new_hdr(monpriv);
243 			if (rc)
244 				goto out_error;
245 			monpriv->data_to_read = monpriv->current_buf ?
246 				monpriv->current_buf->hdr.datalen : 0;
247 		}
248 
249 		if (monpriv->data_to_read) {
250 			len = min(count - written, monpriv->data_to_read);
251 			to = monpriv->current_buf->data +
252 				monpriv->hdr.datalen - monpriv->data_to_read;
253 			if (copy_from_user(to, data + written, len)) {
254 				rc = -EFAULT;
255 				goto out_error;
256 			}
257 			monpriv->data_to_read -= len;
258 			written += len;
259 			if (monpriv->data_to_read > 0)
260 				continue;
261 			rc = monwrite_new_data(monpriv);
262 			if (rc)
263 				goto out_error;
264 		}
265 		monpriv->hdr_to_read = sizeof(monpriv->hdr);
266 	}
267 	mutex_unlock(&monpriv->thread_mutex);
268 	return written;
269 
270 out_error:
271 	monpriv->data_to_read = 0;
272 	monpriv->hdr_to_read = sizeof(struct monwrite_hdr);
273 	mutex_unlock(&monpriv->thread_mutex);
274 	return rc;
275 }
276 
277 static const struct file_operations monwrite_fops = {
278 	.owner	 = THIS_MODULE,
279 	.open	 = &monwrite_open,
280 	.release = &monwrite_close,
281 	.write	 = &monwrite_write,
282 	.llseek  = noop_llseek,
283 };
284 
285 static struct miscdevice mon_dev = {
286 	.name	= "monwriter",
287 	.fops	= &monwrite_fops,
288 	.minor	= MISC_DYNAMIC_MINOR,
289 };
290 
291 /*
292  * module init/exit
293  */
294 
295 static int __init mon_init(void)
296 {
297 	if (!machine_is_vm())
298 		return -ENODEV;
299 	/*
300 	 * misc_register() has to be the last action in module_init(), because
301 	 * file operations will be available right after this.
302 	 */
303 	return misc_register(&mon_dev);
304 }
305 
306 static void __exit mon_exit(void)
307 {
308 	misc_deregister(&mon_dev);
309 }
310 
311 module_init(mon_init);
312 module_exit(mon_exit);
313 
314 module_param_named(max_bufs, mon_max_bufs, int, 0644);
315 MODULE_PARM_DESC(max_bufs, "Maximum number of sample monitor data buffers "
316 		 "that can be active at one time");
317 
318 MODULE_AUTHOR("Melissa Howland <Melissa.Howland@us.ibm.com>");
319 MODULE_DESCRIPTION("Character device driver for writing z/VM "
320 		   "APPLDATA monitor records.");
321 MODULE_LICENSE("GPL");
322