1// SPDX-License-Identifier: GPL-2.0
2/*
3 *   S/390 common I/O routines -- blacklisting of specific devices
4 *
5 *    Copyright IBM Corp. 1999, 2013
6 *    Author(s): Ingo Adlung (adlung@de.ibm.com)
7 *		 Cornelia Huck (cornelia.huck@de.ibm.com)
8 *		 Arnd Bergmann (arndb@de.ibm.com)
9 */
10
11#define KMSG_COMPONENT "cio"
12#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
13
14#include <linux/init.h>
15#include <linux/vmalloc.h>
16#include <linux/proc_fs.h>
17#include <linux/seq_file.h>
18#include <linux/ctype.h>
19#include <linux/device.h>
20
21#include <linux/uaccess.h>
22#include <asm/cio.h>
23#include <asm/ipl.h>
24
25#include "blacklist.h"
26#include "cio.h"
27#include "cio_debug.h"
28#include "css.h"
29#include "device.h"
30
31/*
32 * "Blacklisting" of certain devices:
33 * Device numbers given in the commandline as cio_ignore=... won't be known
34 * to Linux.
35 *
36 * These can be single devices or ranges of devices
37 */
38
39/* 65536 bits for each set to indicate if a devno is blacklisted or not */
40#define __BL_DEV_WORDS ((__MAX_SUBCHANNEL + (8*sizeof(long) - 1)) / \
41			 (8*sizeof(long)))
42static unsigned long bl_dev[__MAX_SSID + 1][__BL_DEV_WORDS];
43typedef enum {add, free} range_action;
44
45/*
46 * Function: blacklist_range
47 * (Un-)blacklist the devices from-to
48 */
49static int blacklist_range(range_action action, unsigned int from_ssid,
50			   unsigned int to_ssid, unsigned int from,
51			   unsigned int to, int msgtrigger)
52{
53	if ((from_ssid > to_ssid) || ((from_ssid == to_ssid) && (from > to))) {
54		if (msgtrigger)
55			pr_warn("0.%x.%04x to 0.%x.%04x is not a valid range for cio_ignore\n",
56				from_ssid, from, to_ssid, to);
57
58		return 1;
59	}
60
61	while ((from_ssid < to_ssid) || ((from_ssid == to_ssid) &&
62	       (from <= to))) {
63		if (action == add)
64			set_bit(from, bl_dev[from_ssid]);
65		else
66			clear_bit(from, bl_dev[from_ssid]);
67		from++;
68		if (from > __MAX_SUBCHANNEL) {
69			from_ssid++;
70			from = 0;
71		}
72	}
73
74	return 0;
75}
76
77static int pure_hex(char **cp, unsigned int *val, int min_digit,
78		    int max_digit, int max_val)
79{
80	int diff;
81
82	diff = 0;
83	*val = 0;
84
85	while (diff <= max_digit) {
86		int value = hex_to_bin(**cp);
87
88		if (value < 0)
89			break;
90		*val = *val * 16 + value;
91		(*cp)++;
92		diff++;
93	}
94
95	if ((diff < min_digit) || (diff > max_digit) || (*val > max_val))
96		return 1;
97
98	return 0;
99}
100
101static int parse_busid(char *str, unsigned int *cssid, unsigned int *ssid,
102		       unsigned int *devno, int msgtrigger)
103{
104	char *str_work;
105	int val, rc, ret;
106
107	rc = 1;
108
109	if (*str == '\0')
110		goto out;
111
112	/* old style */
113	str_work = str;
114	val = simple_strtoul(str, &str_work, 16);
115
116	if (*str_work == '\0') {
117		if (val <= __MAX_SUBCHANNEL) {
118			*devno = val;
119			*ssid = 0;
120			*cssid = 0;
121			rc = 0;
122		}
123		goto out;
124	}
125
126	/* new style */
127	str_work = str;
128	ret = pure_hex(&str_work, cssid, 1, 2, __MAX_CSSID);
129	if (ret || (str_work[0] != '.'))
130		goto out;
131	str_work++;
132	ret = pure_hex(&str_work, ssid, 1, 1, __MAX_SSID);
133	if (ret || (str_work[0] != '.'))
134		goto out;
135	str_work++;
136	ret = pure_hex(&str_work, devno, 4, 4, __MAX_SUBCHANNEL);
137	if (ret || (str_work[0] != '\0'))
138		goto out;
139
140	rc = 0;
141out:
142	if (rc && msgtrigger)
143		pr_warn("%s is not a valid device for the cio_ignore kernel parameter\n",
144			str);
145
146	return rc;
147}
148
149static int blacklist_parse_parameters(char *str, range_action action,
150				      int msgtrigger)
151{
152	unsigned int from_cssid, to_cssid, from_ssid, to_ssid, from, to;
153	int rc, totalrc;
154	char *parm;
155	range_action ra;
156
157	totalrc = 0;
158
159	while ((parm = strsep(&str, ","))) {
160		rc = 0;
161		ra = action;
162		if (*parm == '!') {
163			if (ra == add)
164				ra = free;
165			else
166				ra = add;
167			parm++;
168		}
169		if (strcmp(parm, "all") == 0) {
170			from_cssid = 0;
171			from_ssid = 0;
172			from = 0;
173			to_cssid = __MAX_CSSID;
174			to_ssid = __MAX_SSID;
175			to = __MAX_SUBCHANNEL;
176		} else if (strcmp(parm, "ipldev") == 0) {
177			if (ipl_info.type == IPL_TYPE_CCW) {
178				from_cssid = 0;
179				from_ssid = ipl_info.data.ccw.dev_id.ssid;
180				from = ipl_info.data.ccw.dev_id.devno;
181			} else if (ipl_info.type == IPL_TYPE_FCP ||
182				   ipl_info.type == IPL_TYPE_FCP_DUMP) {
183				from_cssid = 0;
184				from_ssid = ipl_info.data.fcp.dev_id.ssid;
185				from = ipl_info.data.fcp.dev_id.devno;
186			} else {
187				continue;
188			}
189			to_cssid = from_cssid;
190			to_ssid = from_ssid;
191			to = from;
192		} else if (strcmp(parm, "condev") == 0) {
193			if (console_devno == -1)
194				continue;
195
196			from_cssid = to_cssid = 0;
197			from_ssid = to_ssid = 0;
198			from = to = console_devno;
199		} else {
200			rc = parse_busid(strsep(&parm, "-"), &from_cssid,
201					 &from_ssid, &from, msgtrigger);
202			if (!rc) {
203				if (parm != NULL)
204					rc = parse_busid(parm, &to_cssid,
205							 &to_ssid, &to,
206							 msgtrigger);
207				else {
208					to_cssid = from_cssid;
209					to_ssid = from_ssid;
210					to = from;
211				}
212			}
213		}
214		if (!rc) {
215			rc = blacklist_range(ra, from_ssid, to_ssid, from, to,
216					     msgtrigger);
217			if (rc)
218				totalrc = -EINVAL;
219		} else
220			totalrc = -EINVAL;
221	}
222
223	return totalrc;
224}
225
226static int __init
227blacklist_setup (char *str)
228{
229	CIO_MSG_EVENT(6, "Reading blacklist parameters\n");
230	if (blacklist_parse_parameters(str, add, 1))
231		return 0;
232	return 1;
233}
234
235__setup ("cio_ignore=", blacklist_setup);
236
237/* Checking if devices are blacklisted */
238
239/*
240 * Function: is_blacklisted
241 * Returns 1 if the given devicenumber can be found in the blacklist,
242 * otherwise 0.
243 * Used by validate_subchannel()
244 */
245int
246is_blacklisted (int ssid, int devno)
247{
248	return test_bit (devno, bl_dev[ssid]);
249}
250
251#ifdef CONFIG_PROC_FS
252/*
253 * Function: blacklist_parse_proc_parameters
254 * parse the stuff which is piped to /proc/cio_ignore
255 */
256static int blacklist_parse_proc_parameters(char *buf)
257{
258	int rc;
259	char *parm;
260
261	parm = strsep(&buf, " ");
262
263	if (strcmp("free", parm) == 0) {
264		rc = blacklist_parse_parameters(buf, free, 0);
265		/*
266		 * Evaluate the subchannels without an online device. This way,
267		 * no path-verification will be triggered on those subchannels
268		 * and it avoids unnecessary delays.
269		 */
270		css_schedule_eval_cond(CSS_EVAL_NOT_ONLINE, 0);
271	} else if (strcmp("add", parm) == 0)
272		rc = blacklist_parse_parameters(buf, add, 0);
273	else if (strcmp("purge", parm) == 0)
274		return ccw_purge_blacklisted();
275	else
276		return -EINVAL;
277
278
279	return rc;
280}
281
282/* Iterator struct for all devices. */
283struct ccwdev_iter {
284	int devno;
285	int ssid;
286	int in_range;
287};
288
289static void *
290cio_ignore_proc_seq_start(struct seq_file *s, loff_t *offset)
291{
292	struct ccwdev_iter *iter = s->private;
293
294	if (*offset >= (__MAX_SUBCHANNEL + 1) * (__MAX_SSID + 1))
295		return NULL;
296	memset(iter, 0, sizeof(*iter));
297	iter->ssid = *offset / (__MAX_SUBCHANNEL + 1);
298	iter->devno = *offset % (__MAX_SUBCHANNEL + 1);
299	return iter;
300}
301
302static void
303cio_ignore_proc_seq_stop(struct seq_file *s, void *it)
304{
305}
306
307static void *
308cio_ignore_proc_seq_next(struct seq_file *s, void *it, loff_t *offset)
309{
310	struct ccwdev_iter *iter;
311	loff_t p = *offset;
312
313	(*offset)++;
314	if (p >= (__MAX_SUBCHANNEL + 1) * (__MAX_SSID + 1))
315		return NULL;
316	iter = it;
317	if (iter->devno == __MAX_SUBCHANNEL) {
318		iter->devno = 0;
319		iter->ssid++;
320		if (iter->ssid > __MAX_SSID)
321			return NULL;
322	} else
323		iter->devno++;
324	return iter;
325}
326
327static int
328cio_ignore_proc_seq_show(struct seq_file *s, void *it)
329{
330	struct ccwdev_iter *iter;
331
332	iter = it;
333	if (!is_blacklisted(iter->ssid, iter->devno))
334		/* Not blacklisted, nothing to output. */
335		return 0;
336	if (!iter->in_range) {
337		/* First device in range. */
338		if ((iter->devno == __MAX_SUBCHANNEL) ||
339		    !is_blacklisted(iter->ssid, iter->devno + 1)) {
340			/* Singular device. */
341			seq_printf(s, "0.%x.%04x\n", iter->ssid, iter->devno);
342			return 0;
343		}
344		iter->in_range = 1;
345		seq_printf(s, "0.%x.%04x-", iter->ssid, iter->devno);
346		return 0;
347	}
348	if ((iter->devno == __MAX_SUBCHANNEL) ||
349	    !is_blacklisted(iter->ssid, iter->devno + 1)) {
350		/* Last device in range. */
351		iter->in_range = 0;
352		seq_printf(s, "0.%x.%04x\n", iter->ssid, iter->devno);
353	}
354	return 0;
355}
356
357static ssize_t
358cio_ignore_write(struct file *file, const char __user *user_buf,
359		 size_t user_len, loff_t *offset)
360{
361	char *buf;
362	ssize_t rc, ret, i;
363
364	if (*offset)
365		return -EINVAL;
366	if (user_len > 65536)
367		user_len = 65536;
368	buf = vzalloc(user_len + 1); /* maybe better use the stack? */
369	if (buf == NULL)
370		return -ENOMEM;
371
372	if (strncpy_from_user (buf, user_buf, user_len) < 0) {
373		rc = -EFAULT;
374		goto out_free;
375	}
376
377	i = user_len - 1;
378	while ((i >= 0) && (isspace(buf[i]) || (buf[i] == 0))) {
379		buf[i] = '\0';
380		i--;
381	}
382	ret = blacklist_parse_proc_parameters(buf);
383	if (ret)
384		rc = ret;
385	else
386		rc = user_len;
387
388out_free:
389	vfree (buf);
390	return rc;
391}
392
393static const struct seq_operations cio_ignore_proc_seq_ops = {
394	.start = cio_ignore_proc_seq_start,
395	.stop  = cio_ignore_proc_seq_stop,
396	.next  = cio_ignore_proc_seq_next,
397	.show  = cio_ignore_proc_seq_show,
398};
399
400static int
401cio_ignore_proc_open(struct inode *inode, struct file *file)
402{
403	return seq_open_private(file, &cio_ignore_proc_seq_ops,
404				sizeof(struct ccwdev_iter));
405}
406
407static const struct proc_ops cio_ignore_proc_ops = {
408	.proc_open	= cio_ignore_proc_open,
409	.proc_read	= seq_read,
410	.proc_lseek	= seq_lseek,
411	.proc_release	= seq_release_private,
412	.proc_write	= cio_ignore_write,
413};
414
415static int
416cio_ignore_proc_init (void)
417{
418	struct proc_dir_entry *entry;
419
420	entry = proc_create("cio_ignore", S_IFREG | S_IRUGO | S_IWUSR, NULL,
421			    &cio_ignore_proc_ops);
422	if (!entry)
423		return -ENOENT;
424	return 0;
425}
426
427__initcall (cio_ignore_proc_init);
428
429#endif /* CONFIG_PROC_FS */
430