xref: /linux/drivers/s390/cio/blacklist.c (revision 4413e16d9d21673bb5048a2e542f1aaa00015c2e) 
1 /*
2  *   S/390 common I/O routines -- blacklisting of specific devices
3  *
4  *    Copyright IBM Corp. 1999, 2002
5  *    Author(s): Ingo Adlung (adlung@de.ibm.com)
6  *		 Cornelia Huck (cornelia.huck@de.ibm.com)
7  *		 Arnd Bergmann (arndb@de.ibm.com)
8  */
9 
10 #define KMSG_COMPONENT "cio"
11 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
12 
13 #include <linux/init.h>
14 #include <linux/vmalloc.h>
15 #include <linux/proc_fs.h>
16 #include <linux/seq_file.h>
17 #include <linux/ctype.h>
18 #include <linux/device.h>
19 
20 #include <asm/cio.h>
21 #include <asm/uaccess.h>
22 
23 #include "blacklist.h"
24 #include "cio.h"
25 #include "cio_debug.h"
26 #include "css.h"
27 #include "device.h"
28 
29 /*
30  * "Blacklisting" of certain devices:
31  * Device numbers given in the commandline as cio_ignore=... won't be known
32  * to Linux.
33  *
34  * These can be single devices or ranges of devices
35  */
36 
37 /* 65536 bits for each set to indicate if a devno is blacklisted or not */
38 #define __BL_DEV_WORDS ((__MAX_SUBCHANNEL + (8*sizeof(long) - 1)) / \
39 			 (8*sizeof(long)))
40 static unsigned long bl_dev[__MAX_SSID + 1][__BL_DEV_WORDS];
41 typedef enum {add, free} range_action;
42 
43 /*
44  * Function: blacklist_range
45  * (Un-)blacklist the devices from-to
46  */
47 static int blacklist_range(range_action action, unsigned int from_ssid,
48 			   unsigned int to_ssid, unsigned int from,
49 			   unsigned int to, int msgtrigger)
50 {
51 	if ((from_ssid > to_ssid) || ((from_ssid == to_ssid) && (from > to))) {
52 		if (msgtrigger)
53 			pr_warning("0.%x.%04x to 0.%x.%04x is not a valid "
54 				   "range for cio_ignore\n", from_ssid, from,
55 				   to_ssid, to);
56 
57 		return 1;
58 	}
59 
60 	while ((from_ssid < to_ssid) || ((from_ssid == to_ssid) &&
61 	       (from <= to))) {
62 		if (action == add)
63 			set_bit(from, bl_dev[from_ssid]);
64 		else
65 			clear_bit(from, bl_dev[from_ssid]);
66 		from++;
67 		if (from > __MAX_SUBCHANNEL) {
68 			from_ssid++;
69 			from = 0;
70 		}
71 	}
72 
73 	return 0;
74 }
75 
76 static int pure_hex(char **cp, unsigned int *val, int min_digit,
77 		    int max_digit, int max_val)
78 {
79 	int diff;
80 
81 	diff = 0;
82 	*val = 0;
83 
84 	while (diff <= max_digit) {
85 		int value = hex_to_bin(**cp);
86 
87 		if (value < 0)
88 			break;
89 		*val = *val * 16 + value;
90 		(*cp)++;
91 		diff++;
92 	}
93 
94 	if ((diff < min_digit) || (diff > max_digit) || (*val > max_val))
95 		return 1;
96 
97 	return 0;
98 }
99 
100 static int parse_busid(char *str, unsigned int *cssid, unsigned int *ssid,
101 		       unsigned int *devno, int msgtrigger)
102 {
103 	char *str_work;
104 	int val, rc, ret;
105 
106 	rc = 1;
107 
108 	if (*str == '\0')
109 		goto out;
110 
111 	/* old style */
112 	str_work = str;
113 	val = simple_strtoul(str, &str_work, 16);
114 
115 	if (*str_work == '\0') {
116 		if (val <= __MAX_SUBCHANNEL) {
117 			*devno = val;
118 			*ssid = 0;
119 			*cssid = 0;
120 			rc = 0;
121 		}
122 		goto out;
123 	}
124 
125 	/* new style */
126 	str_work = str;
127 	ret = pure_hex(&str_work, cssid, 1, 2, __MAX_CSSID);
128 	if (ret || (str_work[0] != '.'))
129 		goto out;
130 	str_work++;
131 	ret = pure_hex(&str_work, ssid, 1, 1, __MAX_SSID);
132 	if (ret || (str_work[0] != '.'))
133 		goto out;
134 	str_work++;
135 	ret = pure_hex(&str_work, devno, 4, 4, __MAX_SUBCHANNEL);
136 	if (ret || (str_work[0] != '\0'))
137 		goto out;
138 
139 	rc = 0;
140 out:
141 	if (rc && msgtrigger)
142 		pr_warning("%s is not a valid device for the cio_ignore "
143 			   "kernel parameter\n", str);
144 
145 	return rc;
146 }
147 
148 static int blacklist_parse_parameters(char *str, range_action action,
149 				      int msgtrigger)
150 {
151 	unsigned int from_cssid, to_cssid, from_ssid, to_ssid, from, to;
152 	int rc, totalrc;
153 	char *parm;
154 	range_action ra;
155 
156 	totalrc = 0;
157 
158 	while ((parm = strsep(&str, ","))) {
159 		rc = 0;
160 		ra = action;
161 		if (*parm == '!') {
162 			if (ra == add)
163 				ra = free;
164 			else
165 				ra = add;
166 			parm++;
167 		}
168 		if (strcmp(parm, "all") == 0) {
169 			from_cssid = 0;
170 			from_ssid = 0;
171 			from = 0;
172 			to_cssid = __MAX_CSSID;
173 			to_ssid = __MAX_SSID;
174 			to = __MAX_SUBCHANNEL;
175 		} else {
176 			rc = parse_busid(strsep(&parm, "-"), &from_cssid,
177 					 &from_ssid, &from, msgtrigger);
178 			if (!rc) {
179 				if (parm != NULL)
180 					rc = parse_busid(parm, &to_cssid,
181 							 &to_ssid, &to,
182 							 msgtrigger);
183 				else {
184 					to_cssid = from_cssid;
185 					to_ssid = from_ssid;
186 					to = from;
187 				}
188 			}
189 		}
190 		if (!rc) {
191 			rc = blacklist_range(ra, from_ssid, to_ssid, from, to,
192 					     msgtrigger);
193 			if (rc)
194 				totalrc = -EINVAL;
195 		} else
196 			totalrc = -EINVAL;
197 	}
198 
199 	return totalrc;
200 }
201 
202 static int __init
203 blacklist_setup (char *str)
204 {
205 	CIO_MSG_EVENT(6, "Reading blacklist parameters\n");
206 	if (blacklist_parse_parameters(str, add, 1))
207 		return 0;
208 	return 1;
209 }
210 
211 __setup ("cio_ignore=", blacklist_setup);
212 
213 /* Checking if devices are blacklisted */
214 
215 /*
216  * Function: is_blacklisted
217  * Returns 1 if the given devicenumber can be found in the blacklist,
218  * otherwise 0.
219  * Used by validate_subchannel()
220  */
221 int
222 is_blacklisted (int ssid, int devno)
223 {
224 	return test_bit (devno, bl_dev[ssid]);
225 }
226 
227 #ifdef CONFIG_PROC_FS
228 /*
229  * Function: blacklist_parse_proc_parameters
230  * parse the stuff which is piped to /proc/cio_ignore
231  */
232 static int blacklist_parse_proc_parameters(char *buf)
233 {
234 	int rc;
235 	char *parm;
236 
237 	parm = strsep(&buf, " ");
238 
239 	if (strcmp("free", parm) == 0)
240 		rc = blacklist_parse_parameters(buf, free, 0);
241 	else if (strcmp("add", parm) == 0)
242 		rc = blacklist_parse_parameters(buf, add, 0);
243 	else if (strcmp("purge", parm) == 0)
244 		return ccw_purge_blacklisted();
245 	else
246 		return -EINVAL;
247 
248 	css_schedule_reprobe();
249 
250 	return rc;
251 }
252 
253 /* Iterator struct for all devices. */
254 struct ccwdev_iter {
255 	int devno;
256 	int ssid;
257 	int in_range;
258 };
259 
260 static void *
261 cio_ignore_proc_seq_start(struct seq_file *s, loff_t *offset)
262 {
263 	struct ccwdev_iter *iter = s->private;
264 
265 	if (*offset >= (__MAX_SUBCHANNEL + 1) * (__MAX_SSID + 1))
266 		return NULL;
267 	memset(iter, 0, sizeof(*iter));
268 	iter->ssid = *offset / (__MAX_SUBCHANNEL + 1);
269 	iter->devno = *offset % (__MAX_SUBCHANNEL + 1);
270 	return iter;
271 }
272 
273 static void
274 cio_ignore_proc_seq_stop(struct seq_file *s, void *it)
275 {
276 }
277 
278 static void *
279 cio_ignore_proc_seq_next(struct seq_file *s, void *it, loff_t *offset)
280 {
281 	struct ccwdev_iter *iter;
282 
283 	if (*offset >= (__MAX_SUBCHANNEL + 1) * (__MAX_SSID + 1))
284 		return NULL;
285 	iter = it;
286 	if (iter->devno == __MAX_SUBCHANNEL) {
287 		iter->devno = 0;
288 		iter->ssid++;
289 		if (iter->ssid > __MAX_SSID)
290 			return NULL;
291 	} else
292 		iter->devno++;
293 	(*offset)++;
294 	return iter;
295 }
296 
297 static int
298 cio_ignore_proc_seq_show(struct seq_file *s, void *it)
299 {
300 	struct ccwdev_iter *iter;
301 
302 	iter = it;
303 	if (!is_blacklisted(iter->ssid, iter->devno))
304 		/* Not blacklisted, nothing to output. */
305 		return 0;
306 	if (!iter->in_range) {
307 		/* First device in range. */
308 		if ((iter->devno == __MAX_SUBCHANNEL) ||
309 		    !is_blacklisted(iter->ssid, iter->devno + 1))
310 			/* Singular device. */
311 			return seq_printf(s, "0.%x.%04x\n",
312 					  iter->ssid, iter->devno);
313 		iter->in_range = 1;
314 		return seq_printf(s, "0.%x.%04x-", iter->ssid, iter->devno);
315 	}
316 	if ((iter->devno == __MAX_SUBCHANNEL) ||
317 	    !is_blacklisted(iter->ssid, iter->devno + 1)) {
318 		/* Last device in range. */
319 		iter->in_range = 0;
320 		return seq_printf(s, "0.%x.%04x\n", iter->ssid, iter->devno);
321 	}
322 	return 0;
323 }
324 
325 static ssize_t
326 cio_ignore_write(struct file *file, const char __user *user_buf,
327 		 size_t user_len, loff_t *offset)
328 {
329 	char *buf;
330 	ssize_t rc, ret, i;
331 
332 	if (*offset)
333 		return -EINVAL;
334 	if (user_len > 65536)
335 		user_len = 65536;
336 	buf = vzalloc(user_len + 1); /* maybe better use the stack? */
337 	if (buf == NULL)
338 		return -ENOMEM;
339 
340 	if (strncpy_from_user (buf, user_buf, user_len) < 0) {
341 		rc = -EFAULT;
342 		goto out_free;
343 	}
344 
345 	i = user_len - 1;
346 	while ((i >= 0) && (isspace(buf[i]) || (buf[i] == 0))) {
347 		buf[i] = '\0';
348 		i--;
349 	}
350 	ret = blacklist_parse_proc_parameters(buf);
351 	if (ret)
352 		rc = ret;
353 	else
354 		rc = user_len;
355 
356 out_free:
357 	vfree (buf);
358 	return rc;
359 }
360 
361 static const struct seq_operations cio_ignore_proc_seq_ops = {
362 	.start = cio_ignore_proc_seq_start,
363 	.stop  = cio_ignore_proc_seq_stop,
364 	.next  = cio_ignore_proc_seq_next,
365 	.show  = cio_ignore_proc_seq_show,
366 };
367 
368 static int
369 cio_ignore_proc_open(struct inode *inode, struct file *file)
370 {
371 	return seq_open_private(file, &cio_ignore_proc_seq_ops,
372 				sizeof(struct ccwdev_iter));
373 }
374 
375 static const struct file_operations cio_ignore_proc_fops = {
376 	.open    = cio_ignore_proc_open,
377 	.read    = seq_read,
378 	.llseek  = seq_lseek,
379 	.release = seq_release_private,
380 	.write   = cio_ignore_write,
381 };
382 
383 static int
384 cio_ignore_proc_init (void)
385 {
386 	struct proc_dir_entry *entry;
387 
388 	entry = proc_create("cio_ignore", S_IFREG | S_IRUGO | S_IWUSR, NULL,
389 			    &cio_ignore_proc_fops);
390 	if (!entry)
391 		return -ENOENT;
392 	return 0;
393 }
394 
395 __initcall (cio_ignore_proc_init);
396 
397 #endif /* CONFIG_PROC_FS */
398