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
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
42struct 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
55static 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(sizeof(*id), GFP_KERNEL);
62 parm_list = kmalloc(sizeof(*parm_list), GFP_KERNEL);
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;
78out:
79 kfree(objp: id);
80 kfree(objp: parm_list);
81 return rc;
82}
83
84static 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
102static 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(myhdr: monhdr, buffer: monbuf->data,
119 fcn: APPLDATA_STOP_REC);
120 list_del(entry: &monbuf->list);
121 mon_buf_count--;
122 kfree(objp: monbuf->data);
123 kfree(objp: monbuf);
124 monbuf = NULL;
125 }
126 } else if (monhdr->mon_function != MONWRITE_STOP_INTERVAL) {
127 if (mon_buf_count >= mon_max_bufs)
128 return -ENOSPC;
129 monbuf = kzalloc(sizeof(struct mon_buf), GFP_KERNEL);
130 if (!monbuf)
131 return -ENOMEM;
132 monbuf->data = kzalloc(monhdr->datalen,
133 GFP_KERNEL | GFP_DMA);
134 if (!monbuf->data) {
135 kfree(objp: monbuf);
136 return -ENOMEM;
137 }
138 monbuf->hdr = *monhdr;
139 list_add_tail(new: &monbuf->list, head: &monpriv->list);
140 if (monhdr->mon_function != MONWRITE_GEN_EVENT)
141 mon_buf_count++;
142 }
143 monpriv->current_buf = monbuf;
144 return rc;
145}
146
147static int monwrite_new_data(struct mon_private *monpriv)
148{
149 struct monwrite_hdr *monhdr = &monpriv->hdr;
150 struct mon_buf *monbuf = monpriv->current_buf;
151 int rc = 0;
152
153 switch (monhdr->mon_function) {
154 case MONWRITE_START_INTERVAL:
155 if (!monbuf->diag_done) {
156 rc = monwrite_diag(myhdr: monhdr, buffer: monbuf->data,
157 fcn: APPLDATA_START_INTERVAL_REC);
158 monbuf->diag_done = 1;
159 }
160 break;
161 case MONWRITE_START_CONFIG:
162 if (!monbuf->diag_done) {
163 rc = monwrite_diag(myhdr: monhdr, buffer: monbuf->data,
164 fcn: APPLDATA_START_CONFIG_REC);
165 monbuf->diag_done = 1;
166 }
167 break;
168 case MONWRITE_GEN_EVENT:
169 rc = monwrite_diag(myhdr: monhdr, buffer: monbuf->data,
170 fcn: APPLDATA_GEN_EVENT_REC);
171 list_del(entry: &monpriv->current_buf->list);
172 kfree(objp: monpriv->current_buf->data);
173 kfree(objp: monpriv->current_buf);
174 monpriv->current_buf = NULL;
175 break;
176 default:
177 /* monhdr->mon_function is checked in monwrite_new_hdr */
178 BUG();
179 }
180 return rc;
181}
182
183/*
184 * file operations
185 */
186
187static int monwrite_open(struct inode *inode, struct file *filp)
188{
189 struct mon_private *monpriv;
190
191 monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
192 if (!monpriv)
193 return -ENOMEM;
194 INIT_LIST_HEAD(list: &monpriv->list);
195 monpriv->hdr_to_read = sizeof(monpriv->hdr);
196 mutex_init(&monpriv->thread_mutex);
197 filp->private_data = monpriv;
198 return nonseekable_open(inode, filp);
199}
200
201static int monwrite_close(struct inode *inode, struct file *filp)
202{
203 struct mon_private *monpriv = filp->private_data;
204 struct mon_buf *entry, *next;
205
206 list_for_each_entry_safe(entry, next, &monpriv->list, list) {
207 if (entry->hdr.mon_function != MONWRITE_GEN_EVENT)
208 monwrite_diag(myhdr: &entry->hdr, buffer: entry->data,
209 fcn: APPLDATA_STOP_REC);
210 mon_buf_count--;
211 list_del(entry: &entry->list);
212 kfree(objp: entry->data);
213 kfree(objp: entry);
214 }
215 kfree(objp: monpriv);
216 return 0;
217}
218
219static ssize_t monwrite_write(struct file *filp, const char __user *data,
220 size_t count, loff_t *ppos)
221{
222 struct mon_private *monpriv = filp->private_data;
223 size_t len, written;
224 void *to;
225 int rc;
226
227 mutex_lock(&monpriv->thread_mutex);
228 for (written = 0; written < count; ) {
229 if (monpriv->hdr_to_read) {
230 len = min(count - written, monpriv->hdr_to_read);
231 to = (char *) &monpriv->hdr +
232 sizeof(monpriv->hdr) - monpriv->hdr_to_read;
233 if (copy_from_user(to, from: data + written, n: len)) {
234 rc = -EFAULT;
235 goto out_error;
236 }
237 monpriv->hdr_to_read -= len;
238 written += len;
239 if (monpriv->hdr_to_read > 0)
240 continue;
241 rc = monwrite_new_hdr(monpriv);
242 if (rc)
243 goto out_error;
244 monpriv->data_to_read = monpriv->current_buf ?
245 monpriv->current_buf->hdr.datalen : 0;
246 }
247
248 if (monpriv->data_to_read) {
249 len = min(count - written, monpriv->data_to_read);
250 to = monpriv->current_buf->data +
251 monpriv->hdr.datalen - monpriv->data_to_read;
252 if (copy_from_user(to, from: data + written, n: len)) {
253 rc = -EFAULT;
254 goto out_error;
255 }
256 monpriv->data_to_read -= len;
257 written += len;
258 if (monpriv->data_to_read > 0)
259 continue;
260 rc = monwrite_new_data(monpriv);
261 if (rc)
262 goto out_error;
263 }
264 monpriv->hdr_to_read = sizeof(monpriv->hdr);
265 }
266 mutex_unlock(lock: &monpriv->thread_mutex);
267 return written;
268
269out_error:
270 monpriv->data_to_read = 0;
271 monpriv->hdr_to_read = sizeof(struct monwrite_hdr);
272 mutex_unlock(lock: &monpriv->thread_mutex);
273 return rc;
274}
275
276static const struct file_operations monwrite_fops = {
277 .owner = THIS_MODULE,
278 .open = &monwrite_open,
279 .release = &monwrite_close,
280 .write = &monwrite_write,
281 .llseek = noop_llseek,
282};
283
284static struct miscdevice mon_dev = {
285 .name = "monwriter",
286 .fops = &monwrite_fops,
287 .minor = MISC_DYNAMIC_MINOR,
288};
289
290/*
291 * module init/exit
292 */
293
294static int __init mon_init(void)
295{
296 if (!machine_is_vm())
297 return -ENODEV;
298 /*
299 * misc_register() has to be the last action in module_init(), because
300 * file operations will be available right after this.
301 */
302 return misc_register(misc: &mon_dev);
303}
304
305static void __exit mon_exit(void)
306{
307 misc_deregister(misc: &mon_dev);
308}
309
310module_init(mon_init);
311module_exit(mon_exit);
312
313module_param_named(max_bufs, mon_max_bufs, int, 0644);
314MODULE_PARM_DESC(max_bufs, "Maximum number of sample monitor data buffers "
315 "that can be active at one time");
316
317MODULE_AUTHOR("Melissa Howland <Melissa.Howland@us.ibm.com>");
318MODULE_DESCRIPTION("Character device driver for writing z/VM "
319 "APPLDATA monitor records.");
320MODULE_LICENSE("GPL");
321

source code of linux/drivers/s390/char/monwriter.c