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 pr_fmt(fmt) "monwriter: " 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/slab.h>
23 #include <linux/uaccess.h>
24 #include <linux/io.h>
25 #include <asm/machine.h>
26 #include <asm/ebcdic.h>
27 #include <asm/appldata.h>
28 #include <asm/monwriter.h>
29
30 #define MONWRITE_MAX_DATALEN 4010
31
32 static int mon_max_bufs = 255;
33 static int mon_buf_count;
34
35 struct mon_buf {
36 struct list_head list;
37 struct monwrite_hdr hdr;
38 int diag_done;
39 char *data;
40 };
41
42 struct mon_private {
43 struct list_head list;
44 struct monwrite_hdr hdr;
45 size_t hdr_to_read;
46 size_t data_to_read;
47 struct mon_buf *current_buf;
48 struct mutex thread_mutex;
49 };
50
51 /*
52 * helper functions
53 */
54
monwrite_diag(struct monwrite_hdr * myhdr,char * buffer,int fcn)55 static int monwrite_diag(struct monwrite_hdr *myhdr, char *buffer, int fcn)
56 {
57 struct appldata_parameter_list *parm_list;
58 struct appldata_product_id *id;
59 int rc;
60
61 id = kmalloc_obj(*id);
62 parm_list = kmalloc_obj(*parm_list);
63 rc = -ENOMEM;
64 if (!id || !parm_list)
65 goto out;
66 memcpy(id->prod_nr, "LNXAPPL", 7);
67 id->prod_fn = myhdr->applid;
68 id->record_nr = myhdr->record_num;
69 id->version_nr = myhdr->version;
70 id->release_nr = myhdr->release;
71 id->mod_lvl = myhdr->mod_level;
72 rc = appldata_asm(parm_list, id, fcn,
73 (void *) buffer, myhdr->datalen);
74 if (rc <= 0)
75 goto out;
76 pr_err("Writing monitor data failed with rc=%i\n", rc);
77 rc = (rc == 5) ? -EPERM : -EINVAL;
78 out:
79 kfree(id);
80 kfree(parm_list);
81 return rc;
82 }
83
monwrite_find_hdr(struct mon_private * monpriv,struct monwrite_hdr * monhdr)84 static struct mon_buf *monwrite_find_hdr(struct mon_private *monpriv,
85 struct monwrite_hdr *monhdr)
86 {
87 struct mon_buf *entry, *next;
88
89 list_for_each_entry_safe(entry, next, &monpriv->list, list)
90 if ((entry->hdr.mon_function == monhdr->mon_function ||
91 monhdr->mon_function == MONWRITE_STOP_INTERVAL) &&
92 entry->hdr.applid == monhdr->applid &&
93 entry->hdr.record_num == monhdr->record_num &&
94 entry->hdr.version == monhdr->version &&
95 entry->hdr.release == monhdr->release &&
96 entry->hdr.mod_level == monhdr->mod_level)
97 return entry;
98
99 return NULL;
100 }
101
monwrite_new_hdr(struct mon_private * monpriv)102 static int monwrite_new_hdr(struct mon_private *monpriv)
103 {
104 struct monwrite_hdr *monhdr = &monpriv->hdr;
105 struct mon_buf *monbuf;
106 int rc = 0;
107
108 if (monhdr->datalen > MONWRITE_MAX_DATALEN ||
109 monhdr->mon_function > MONWRITE_START_CONFIG ||
110 monhdr->hdrlen != sizeof(struct monwrite_hdr))
111 return -EINVAL;
112 monbuf = NULL;
113 if (monhdr->mon_function != MONWRITE_GEN_EVENT)
114 monbuf = monwrite_find_hdr(monpriv, monhdr);
115 if (monbuf) {
116 if (monhdr->mon_function == MONWRITE_STOP_INTERVAL) {
117 monhdr->datalen = monbuf->hdr.datalen;
118 rc = monwrite_diag(monhdr, monbuf->data,
119 APPLDATA_STOP_REC);
120 list_del(&monbuf->list);
121 mon_buf_count--;
122 kfree(monbuf->data);
123 kfree(monbuf);
124 monbuf = NULL;
125 } else if (monbuf->hdr.datalen != monhdr->datalen) {
126 /* Data with buffer reuse must not change its length */
127 return -EINVAL;
128 }
129 } else if (monhdr->mon_function != MONWRITE_STOP_INTERVAL) {
130 if (mon_buf_count >= mon_max_bufs)
131 return -ENOSPC;
132 monbuf = kzalloc_obj(struct mon_buf);
133 if (!monbuf)
134 return -ENOMEM;
135 monbuf->data = kzalloc(monhdr->datalen,
136 GFP_KERNEL | GFP_DMA);
137 if (!monbuf->data) {
138 kfree(monbuf);
139 return -ENOMEM;
140 }
141 monbuf->hdr = *monhdr;
142 list_add_tail(&monbuf->list, &monpriv->list);
143 if (monhdr->mon_function != MONWRITE_GEN_EVENT)
144 mon_buf_count++;
145 }
146 monpriv->current_buf = monbuf;
147 return rc;
148 }
149
monwrite_new_data(struct mon_private * monpriv)150 static int monwrite_new_data(struct mon_private *monpriv)
151 {
152 struct monwrite_hdr *monhdr = &monpriv->hdr;
153 struct mon_buf *monbuf = monpriv->current_buf;
154 int rc = 0;
155
156 switch (monhdr->mon_function) {
157 case MONWRITE_START_INTERVAL:
158 if (!monbuf->diag_done) {
159 rc = monwrite_diag(monhdr, monbuf->data,
160 APPLDATA_START_INTERVAL_REC);
161 monbuf->diag_done = 1;
162 }
163 break;
164 case MONWRITE_START_CONFIG:
165 if (!monbuf->diag_done) {
166 rc = monwrite_diag(monhdr, monbuf->data,
167 APPLDATA_START_CONFIG_REC);
168 monbuf->diag_done = 1;
169 }
170 break;
171 case MONWRITE_GEN_EVENT:
172 rc = monwrite_diag(monhdr, monbuf->data,
173 APPLDATA_GEN_EVENT_REC);
174 list_del(&monpriv->current_buf->list);
175 kfree(monpriv->current_buf->data);
176 kfree(monpriv->current_buf);
177 monpriv->current_buf = NULL;
178 break;
179 default:
180 /* monhdr->mon_function is checked in monwrite_new_hdr */
181 BUG();
182 }
183 return rc;
184 }
185
186 /*
187 * file operations
188 */
189
monwrite_open(struct inode * inode,struct file * filp)190 static int monwrite_open(struct inode *inode, struct file *filp)
191 {
192 struct mon_private *monpriv;
193
194 monpriv = kzalloc_obj(struct mon_private);
195 if (!monpriv)
196 return -ENOMEM;
197 INIT_LIST_HEAD(&monpriv->list);
198 monpriv->hdr_to_read = sizeof(monpriv->hdr);
199 mutex_init(&monpriv->thread_mutex);
200 filp->private_data = monpriv;
201 return nonseekable_open(inode, filp);
202 }
203
monwrite_close(struct inode * inode,struct file * filp)204 static int monwrite_close(struct inode *inode, struct file *filp)
205 {
206 struct mon_private *monpriv = filp->private_data;
207 struct mon_buf *entry, *next;
208
209 list_for_each_entry_safe(entry, next, &monpriv->list, list) {
210 if (entry->hdr.mon_function != MONWRITE_GEN_EVENT)
211 monwrite_diag(&entry->hdr, entry->data,
212 APPLDATA_STOP_REC);
213 mon_buf_count--;
214 list_del(&entry->list);
215 kfree(entry->data);
216 kfree(entry);
217 }
218 kfree(monpriv);
219 return 0;
220 }
221
monwrite_write(struct file * filp,const char __user * data,size_t count,loff_t * ppos)222 static ssize_t monwrite_write(struct file *filp, const char __user *data,
223 size_t count, loff_t *ppos)
224 {
225 struct mon_private *monpriv = filp->private_data;
226 size_t len, written;
227 void *to;
228 int rc;
229
230 mutex_lock(&monpriv->thread_mutex);
231 for (written = 0; written < count; ) {
232 if (monpriv->hdr_to_read) {
233 len = min(count - written, monpriv->hdr_to_read);
234 to = (char *) &monpriv->hdr +
235 sizeof(monpriv->hdr) - monpriv->hdr_to_read;
236 if (copy_from_user(to, data + written, len)) {
237 rc = -EFAULT;
238 goto out_error;
239 }
240 monpriv->hdr_to_read -= len;
241 written += len;
242 if (monpriv->hdr_to_read > 0)
243 continue;
244 rc = monwrite_new_hdr(monpriv);
245 if (rc)
246 goto out_error;
247 monpriv->data_to_read = monpriv->current_buf ?
248 monpriv->current_buf->hdr.datalen : 0;
249 }
250
251 if (monpriv->data_to_read) {
252 len = min(count - written, monpriv->data_to_read);
253 to = monpriv->current_buf->data +
254 monpriv->hdr.datalen - monpriv->data_to_read;
255 if (copy_from_user(to, data + written, len)) {
256 rc = -EFAULT;
257 goto out_error;
258 }
259 monpriv->data_to_read -= len;
260 written += len;
261 if (monpriv->data_to_read > 0)
262 continue;
263 rc = monwrite_new_data(monpriv);
264 if (rc)
265 goto out_error;
266 }
267 monpriv->hdr_to_read = sizeof(monpriv->hdr);
268 }
269 mutex_unlock(&monpriv->thread_mutex);
270 return written;
271
272 out_error:
273 monpriv->data_to_read = 0;
274 monpriv->hdr_to_read = sizeof(struct monwrite_hdr);
275 mutex_unlock(&monpriv->thread_mutex);
276 return rc;
277 }
278
279 static const struct file_operations monwrite_fops = {
280 .owner = THIS_MODULE,
281 .open = &monwrite_open,
282 .release = &monwrite_close,
283 .write = &monwrite_write,
284 .llseek = noop_llseek,
285 };
286
287 static struct miscdevice mon_dev = {
288 .name = "monwriter",
289 .fops = &monwrite_fops,
290 .minor = MISC_DYNAMIC_MINOR,
291 };
292
293 /*
294 * module init/exit
295 */
296
mon_init(void)297 static int __init mon_init(void)
298 {
299 if (!machine_is_vm())
300 return -ENODEV;
301 /*
302 * misc_register() has to be the last action in module_init(), because
303 * file operations will be available right after this.
304 */
305 return misc_register(&mon_dev);
306 }
307
mon_exit(void)308 static void __exit mon_exit(void)
309 {
310 misc_deregister(&mon_dev);
311 }
312
313 module_init(mon_init);
314 module_exit(mon_exit);
315
316 module_param_named(max_bufs, mon_max_bufs, int, 0644);
317 MODULE_PARM_DESC(max_bufs, "Maximum number of sample monitor data buffers "
318 "that can be active at one time");
319
320 MODULE_AUTHOR("Melissa Howland <Melissa.Howland@us.ibm.com>");
321 MODULE_DESCRIPTION("Character device driver for writing z/VM "
322 "APPLDATA monitor records.");
323 MODULE_LICENSE("GPL");
324