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/platform_device.h>
24 #include <linux/slab.h>
25 #include <linux/uaccess.h>
26 #include <asm/ebcdic.h>
27 #include <asm/io.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 static LIST_HEAD(mon_priv_list);
44 
45 struct mon_private {
46 	struct list_head priv_list;
47 	struct list_head list;
48 	struct monwrite_hdr hdr;
49 	size_t hdr_to_read;
50 	size_t data_to_read;
51 	struct mon_buf *current_buf;
52 	struct mutex thread_mutex;
53 };
54 
55 /*
56  * helper functions
57  */
58 
monwrite_diag(struct monwrite_hdr * myhdr,char * buffer,int fcn)59 static int monwrite_diag(struct monwrite_hdr *myhdr, char *buffer, int fcn)
60 {
61 	struct appldata_parameter_list *parm_list;
62 	struct appldata_product_id *id;
63 	int rc;
64 
65 	id = kmalloc(sizeof(*id), GFP_KERNEL);
66 	parm_list = kmalloc(sizeof(*parm_list), GFP_KERNEL);
67 	rc = -ENOMEM;
68 	if (!id || !parm_list)
69 		goto out;
70 	memcpy(id->prod_nr, "LNXAPPL", 7);
71 	id->prod_fn = myhdr->applid;
72 	id->record_nr = myhdr->record_num;
73 	id->version_nr = myhdr->version;
74 	id->release_nr = myhdr->release;
75 	id->mod_lvl = myhdr->mod_level;
76 	rc = appldata_asm(parm_list, id, fcn,
77 			  (void *) buffer, myhdr->datalen);
78 	if (rc <= 0)
79 		goto out;
80 	pr_err("Writing monitor data failed with rc=%i\n", rc);
81 	rc = (rc == 5) ? -EPERM : -EINVAL;
82 out:
83 	kfree(id);
84 	kfree(parm_list);
85 	return rc;
86 }
87 
monwrite_find_hdr(struct mon_private * monpriv,struct monwrite_hdr * monhdr)88 static struct mon_buf *monwrite_find_hdr(struct mon_private *monpriv,
89 					 struct monwrite_hdr *monhdr)
90 {
91 	struct mon_buf *entry, *next;
92 
93 	list_for_each_entry_safe(entry, next, &monpriv->list, list)
94 		if ((entry->hdr.mon_function == monhdr->mon_function ||
95 		     monhdr->mon_function == MONWRITE_STOP_INTERVAL) &&
96 		    entry->hdr.applid == monhdr->applid &&
97 		    entry->hdr.record_num == monhdr->record_num &&
98 		    entry->hdr.version == monhdr->version &&
99 		    entry->hdr.release == monhdr->release &&
100 		    entry->hdr.mod_level == monhdr->mod_level)
101 			return entry;
102 
103 	return NULL;
104 }
105 
monwrite_new_hdr(struct mon_private * monpriv)106 static int monwrite_new_hdr(struct mon_private *monpriv)
107 {
108 	struct monwrite_hdr *monhdr = &monpriv->hdr;
109 	struct mon_buf *monbuf;
110 	int rc = 0;
111 
112 	if (monhdr->datalen > MONWRITE_MAX_DATALEN ||
113 	    monhdr->mon_function > MONWRITE_START_CONFIG ||
114 	    monhdr->hdrlen != sizeof(struct monwrite_hdr))
115 		return -EINVAL;
116 	monbuf = NULL;
117 	if (monhdr->mon_function != MONWRITE_GEN_EVENT)
118 		monbuf = monwrite_find_hdr(monpriv, monhdr);
119 	if (monbuf) {
120 		if (monhdr->mon_function == MONWRITE_STOP_INTERVAL) {
121 			monhdr->datalen = monbuf->hdr.datalen;
122 			rc = monwrite_diag(monhdr, monbuf->data,
123 					   APPLDATA_STOP_REC);
124 			list_del(&monbuf->list);
125 			mon_buf_count--;
126 			kfree(monbuf->data);
127 			kfree(monbuf);
128 			monbuf = NULL;
129 		}
130 	} else if (monhdr->mon_function != MONWRITE_STOP_INTERVAL) {
131 		if (mon_buf_count >= mon_max_bufs)
132 			return -ENOSPC;
133 		monbuf = kzalloc(sizeof(struct mon_buf), GFP_KERNEL);
134 		if (!monbuf)
135 			return -ENOMEM;
136 		monbuf->data = kzalloc(monhdr->datalen,
137 				       GFP_KERNEL | GFP_DMA);
138 		if (!monbuf->data) {
139 			kfree(monbuf);
140 			return -ENOMEM;
141 		}
142 		monbuf->hdr = *monhdr;
143 		list_add_tail(&monbuf->list, &monpriv->list);
144 		if (monhdr->mon_function != MONWRITE_GEN_EVENT)
145 			mon_buf_count++;
146 	}
147 	monpriv->current_buf = monbuf;
148 	return rc;
149 }
150 
monwrite_new_data(struct mon_private * monpriv)151 static int monwrite_new_data(struct mon_private *monpriv)
152 {
153 	struct monwrite_hdr *monhdr = &monpriv->hdr;
154 	struct mon_buf *monbuf = monpriv->current_buf;
155 	int rc = 0;
156 
157 	switch (monhdr->mon_function) {
158 	case MONWRITE_START_INTERVAL:
159 		if (!monbuf->diag_done) {
160 			rc = monwrite_diag(monhdr, monbuf->data,
161 					   APPLDATA_START_INTERVAL_REC);
162 			monbuf->diag_done = 1;
163 		}
164 		break;
165 	case MONWRITE_START_CONFIG:
166 		if (!monbuf->diag_done) {
167 			rc = monwrite_diag(monhdr, monbuf->data,
168 					   APPLDATA_START_CONFIG_REC);
169 			monbuf->diag_done = 1;
170 		}
171 		break;
172 	case MONWRITE_GEN_EVENT:
173 		rc = monwrite_diag(monhdr, monbuf->data,
174 				   APPLDATA_GEN_EVENT_REC);
175 		list_del(&monpriv->current_buf->list);
176 		kfree(monpriv->current_buf->data);
177 		kfree(monpriv->current_buf);
178 		monpriv->current_buf = NULL;
179 		break;
180 	default:
181 		/* monhdr->mon_function is checked in monwrite_new_hdr */
182 		BUG();
183 	}
184 	return rc;
185 }
186 
187 /*
188  * file operations
189  */
190 
monwrite_open(struct inode * inode,struct file * filp)191 static int monwrite_open(struct inode *inode, struct file *filp)
192 {
193 	struct mon_private *monpriv;
194 
195 	monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
196 	if (!monpriv)
197 		return -ENOMEM;
198 	INIT_LIST_HEAD(&monpriv->list);
199 	monpriv->hdr_to_read = sizeof(monpriv->hdr);
200 	mutex_init(&monpriv->thread_mutex);
201 	filp->private_data = monpriv;
202 	list_add_tail(&monpriv->priv_list, &mon_priv_list);
203 	return nonseekable_open(inode, filp);
204 }
205 
monwrite_close(struct inode * inode,struct file * filp)206 static int monwrite_close(struct inode *inode, struct file *filp)
207 {
208 	struct mon_private *monpriv = filp->private_data;
209 	struct mon_buf *entry, *next;
210 
211 	list_for_each_entry_safe(entry, next, &monpriv->list, list) {
212 		if (entry->hdr.mon_function != MONWRITE_GEN_EVENT)
213 			monwrite_diag(&entry->hdr, entry->data,
214 				      APPLDATA_STOP_REC);
215 		mon_buf_count--;
216 		list_del(&entry->list);
217 		kfree(entry->data);
218 		kfree(entry);
219 	}
220 	list_del(&monpriv->priv_list);
221 	kfree(monpriv);
222 	return 0;
223 }
224 
monwrite_write(struct file * filp,const char __user * data,size_t count,loff_t * ppos)225 static ssize_t monwrite_write(struct file *filp, const char __user *data,
226 			      size_t count, loff_t *ppos)
227 {
228 	struct mon_private *monpriv = filp->private_data;
229 	size_t len, written;
230 	void *to;
231 	int rc;
232 
233 	mutex_lock(&monpriv->thread_mutex);
234 	for (written = 0; written < count; ) {
235 		if (monpriv->hdr_to_read) {
236 			len = min(count - written, monpriv->hdr_to_read);
237 			to = (char *) &monpriv->hdr +
238 				sizeof(monpriv->hdr) - monpriv->hdr_to_read;
239 			if (copy_from_user(to, data + written, len)) {
240 				rc = -EFAULT;
241 				goto out_error;
242 			}
243 			monpriv->hdr_to_read -= len;
244 			written += len;
245 			if (monpriv->hdr_to_read > 0)
246 				continue;
247 			rc = monwrite_new_hdr(monpriv);
248 			if (rc)
249 				goto out_error;
250 			monpriv->data_to_read = monpriv->current_buf ?
251 				monpriv->current_buf->hdr.datalen : 0;
252 		}
253 
254 		if (monpriv->data_to_read) {
255 			len = min(count - written, monpriv->data_to_read);
256 			to = monpriv->current_buf->data +
257 				monpriv->hdr.datalen - monpriv->data_to_read;
258 			if (copy_from_user(to, data + written, len)) {
259 				rc = -EFAULT;
260 				goto out_error;
261 			}
262 			monpriv->data_to_read -= len;
263 			written += len;
264 			if (monpriv->data_to_read > 0)
265 				continue;
266 			rc = monwrite_new_data(monpriv);
267 			if (rc)
268 				goto out_error;
269 		}
270 		monpriv->hdr_to_read = sizeof(monpriv->hdr);
271 	}
272 	mutex_unlock(&monpriv->thread_mutex);
273 	return written;
274 
275 out_error:
276 	monpriv->data_to_read = 0;
277 	monpriv->hdr_to_read = sizeof(struct monwrite_hdr);
278 	mutex_unlock(&monpriv->thread_mutex);
279 	return rc;
280 }
281 
282 static const struct file_operations monwrite_fops = {
283 	.owner	 = THIS_MODULE,
284 	.open	 = &monwrite_open,
285 	.release = &monwrite_close,
286 	.write	 = &monwrite_write,
287 	.llseek  = noop_llseek,
288 };
289 
290 static struct miscdevice mon_dev = {
291 	.name	= "monwriter",
292 	.fops	= &monwrite_fops,
293 	.minor	= MISC_DYNAMIC_MINOR,
294 };
295 
296 /*
297  * suspend/resume
298  */
299 
monwriter_freeze(struct device * dev)300 static int monwriter_freeze(struct device *dev)
301 {
302 	struct mon_private *monpriv;
303 	struct mon_buf *monbuf;
304 
305 	list_for_each_entry(monpriv, &mon_priv_list, priv_list) {
306 		list_for_each_entry(monbuf, &monpriv->list, list) {
307 			if (monbuf->hdr.mon_function != MONWRITE_GEN_EVENT)
308 				monwrite_diag(&monbuf->hdr, monbuf->data,
309 					      APPLDATA_STOP_REC);
310 		}
311 	}
312 	return 0;
313 }
314 
monwriter_restore(struct device * dev)315 static int monwriter_restore(struct device *dev)
316 {
317 	struct mon_private *monpriv;
318 	struct mon_buf *monbuf;
319 
320 	list_for_each_entry(monpriv, &mon_priv_list, priv_list) {
321 		list_for_each_entry(monbuf, &monpriv->list, list) {
322 			if (monbuf->hdr.mon_function == MONWRITE_START_INTERVAL)
323 				monwrite_diag(&monbuf->hdr, monbuf->data,
324 					      APPLDATA_START_INTERVAL_REC);
325 			if (monbuf->hdr.mon_function == MONWRITE_START_CONFIG)
326 				monwrite_diag(&monbuf->hdr, monbuf->data,
327 					      APPLDATA_START_CONFIG_REC);
328 		}
329 	}
330 	return 0;
331 }
332 
monwriter_thaw(struct device * dev)333 static int monwriter_thaw(struct device *dev)
334 {
335 	return monwriter_restore(dev);
336 }
337 
338 static const struct dev_pm_ops monwriter_pm_ops = {
339 	.freeze		= monwriter_freeze,
340 	.thaw		= monwriter_thaw,
341 	.restore	= monwriter_restore,
342 };
343 
344 static struct platform_driver monwriter_pdrv = {
345 	.driver = {
346 		.name	= "monwriter",
347 		.pm	= &monwriter_pm_ops,
348 	},
349 };
350 
351 static struct platform_device *monwriter_pdev;
352 
353 /*
354  * module init/exit
355  */
356 
mon_init(void)357 static int __init mon_init(void)
358 {
359 	int rc;
360 
361 	if (!MACHINE_IS_VM)
362 		return -ENODEV;
363 
364 	rc = platform_driver_register(&monwriter_pdrv);
365 	if (rc)
366 		return rc;
367 
368 	monwriter_pdev = platform_device_register_simple("monwriter", -1, NULL,
369 							0);
370 	if (IS_ERR(monwriter_pdev)) {
371 		rc = PTR_ERR(monwriter_pdev);
372 		goto out_driver;
373 	}
374 
375 	/*
376 	 * misc_register() has to be the last action in module_init(), because
377 	 * file operations will be available right after this.
378 	 */
379 	rc = misc_register(&mon_dev);
380 	if (rc)
381 		goto out_device;
382 	return 0;
383 
384 out_device:
385 	platform_device_unregister(monwriter_pdev);
386 out_driver:
387 	platform_driver_unregister(&monwriter_pdrv);
388 	return rc;
389 }
390 
mon_exit(void)391 static void __exit mon_exit(void)
392 {
393 	misc_deregister(&mon_dev);
394 	platform_device_unregister(monwriter_pdev);
395 	platform_driver_unregister(&monwriter_pdrv);
396 }
397 
398 module_init(mon_init);
399 module_exit(mon_exit);
400 
401 module_param_named(max_bufs, mon_max_bufs, int, 0644);
402 MODULE_PARM_DESC(max_bufs, "Maximum number of sample monitor data buffers "
403 		 "that can be active at one time");
404 
405 MODULE_AUTHOR("Melissa Howland <Melissa.Howland@us.ibm.com>");
406 MODULE_DESCRIPTION("Character device driver for writing z/VM "
407 		   "APPLDATA monitor records.");
408 MODULE_LICENSE("GPL");
409