xref: /linux/block/partitions/ibm.c (revision 30e48a75df9c6ead93866bdf1511ca6ecfe17fbe)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
4  *                  Volker Sameske <sameske@de.ibm.com>
5  * Bugreports.to..: <Linux390@de.ibm.com>
6  * Copyright IBM Corp. 1999, 2012
7  */
8 
9 #include <linux/buffer_head.h>
10 #include <linux/hdreg.h>
11 #include <linux/slab.h>
12 #include <asm/dasd.h>
13 #include <asm/ebcdic.h>
14 #include <linux/uaccess.h>
15 #include <asm/vtoc.h>
16 #include <linux/module.h>
17 #include <linux/dasd_mod.h>
18 
19 #include "check.h"
20 
21 union label_t {
22 	struct vtoc_volume_label_cdl vol;
23 	struct vtoc_volume_label_ldl lnx;
24 	struct vtoc_cms_label cms;
25 };
26 
27 /*
28  * compute the block number from a
29  * cyl-cyl-head-head structure
30  */
31 static sector_t cchh2blk(struct vtoc_cchh *ptr, struct hd_geometry *geo)
32 {
33 	sector_t cyl;
34 	__u16 head;
35 
36 	/* decode cylinder and heads for large volumes */
37 	cyl = ptr->hh & 0xFFF0;
38 	cyl <<= 12;
39 	cyl |= ptr->cc;
40 	head = ptr->hh & 0x000F;
41 	return cyl * geo->heads * geo->sectors +
42 	       head * geo->sectors;
43 }
44 
45 /*
46  * compute the block number from a
47  * cyl-cyl-head-head-block structure
48  */
49 static sector_t cchhb2blk(struct vtoc_cchhb *ptr, struct hd_geometry *geo)
50 {
51 	sector_t cyl;
52 	__u16 head;
53 
54 	/* decode cylinder and heads for large volumes */
55 	cyl = ptr->hh & 0xFFF0;
56 	cyl <<= 12;
57 	cyl |= ptr->cc;
58 	head = ptr->hh & 0x000F;
59 	return	cyl * geo->heads * geo->sectors +
60 		head * geo->sectors +
61 		ptr->b;
62 }
63 
64 /* Volume Label Type/ID Length */
65 #define DASD_VOL_TYPE_LEN	4
66 #define DASD_VOL_ID_LEN		6
67 
68 /* Volume Label Types */
69 #define DASD_VOLLBL_TYPE_VOL1 0
70 #define DASD_VOLLBL_TYPE_LNX1 1
71 #define DASD_VOLLBL_TYPE_CMS1 2
72 
73 struct dasd_vollabel {
74 	char *type;
75 	int idx;
76 };
77 
78 static struct dasd_vollabel dasd_vollabels[] = {
79 	[DASD_VOLLBL_TYPE_VOL1] = {
80 		.type = "VOL1",
81 		.idx = DASD_VOLLBL_TYPE_VOL1,
82 	},
83 	[DASD_VOLLBL_TYPE_LNX1] = {
84 		.type = "LNX1",
85 		.idx = DASD_VOLLBL_TYPE_LNX1,
86 	},
87 	[DASD_VOLLBL_TYPE_CMS1] = {
88 		.type = "CMS1",
89 		.idx = DASD_VOLLBL_TYPE_CMS1,
90 	},
91 };
92 
93 static int get_label_by_type(const char *type)
94 {
95 	int i;
96 
97 	for (i = 0; i < ARRAY_SIZE(dasd_vollabels); i++) {
98 		if (!memcmp(type, dasd_vollabels[i].type, DASD_VOL_TYPE_LEN))
99 			return dasd_vollabels[i].idx;
100 	}
101 
102 	return -1;
103 }
104 
105 static int find_label(struct parsed_partitions *state,
106 		      dasd_information2_t *info,
107 		      struct hd_geometry *geo,
108 		      int blocksize,
109 		      sector_t *labelsect,
110 		      char name[],
111 		      char type[],
112 		      union label_t *label)
113 {
114 	sector_t testsect[3];
115 	int i, testcount;
116 	Sector sect;
117 	void *data;
118 
119 	/* There a three places where we may find a valid label:
120 	 * - on an ECKD disk it's block 2
121 	 * - on an FBA disk it's block 1
122 	 * - on an CMS formatted FBA disk it is sector 1, even if the block size
123 	 *   is larger than 512 bytes (possible if the DIAG discipline is used)
124 	 * If we have a valid info structure, then we know exactly which case we
125 	 * have, otherwise we just search through all possebilities.
126 	 */
127 	if (info) {
128 		if ((info->cu_type == 0x6310 && info->dev_type == 0x9336) ||
129 		    (info->cu_type == 0x3880 && info->dev_type == 0x3370))
130 			testsect[0] = info->label_block;
131 		else
132 			testsect[0] = info->label_block * (blocksize >> 9);
133 		testcount = 1;
134 	} else {
135 		testsect[0] = 1;
136 		testsect[1] = (blocksize >> 9);
137 		testsect[2] = 2 * (blocksize >> 9);
138 		testcount = 3;
139 	}
140 	for (i = 0; i < testcount; ++i) {
141 		data = read_part_sector(state, testsect[i], &sect);
142 		if (data == NULL)
143 			continue;
144 		memcpy(label, data, sizeof(*label));
145 		memcpy(type, data, DASD_VOL_TYPE_LEN);
146 		EBCASC(type, DASD_VOL_TYPE_LEN);
147 		put_dev_sector(sect);
148 		switch (get_label_by_type(type)) {
149 		case DASD_VOLLBL_TYPE_VOL1:
150 			memcpy(name, label->vol.volid, DASD_VOL_ID_LEN);
151 			EBCASC(name, DASD_VOL_ID_LEN);
152 			*labelsect = testsect[i];
153 			return 1;
154 		case DASD_VOLLBL_TYPE_LNX1:
155 		case DASD_VOLLBL_TYPE_CMS1:
156 			memcpy(name, label->lnx.volid, DASD_VOL_ID_LEN);
157 			EBCASC(name, DASD_VOL_ID_LEN);
158 			*labelsect = testsect[i];
159 			return 1;
160 		default:
161 			break;
162 		}
163 	}
164 
165 	return 0;
166 }
167 
168 static int find_vol1_partitions(struct parsed_partitions *state,
169 				struct hd_geometry *geo,
170 				int blocksize,
171 				char name[],
172 				union label_t *label)
173 {
174 	sector_t blk;
175 	int counter;
176 	char tmp[64];
177 	Sector sect;
178 	unsigned char *data;
179 	loff_t offset, size;
180 	struct vtoc_format1_label f1;
181 	int secperblk;
182 
183 	snprintf(tmp, sizeof(tmp), "VOL1/%8s:", name);
184 	strlcat(state->pp_buf, tmp, PAGE_SIZE);
185 	/*
186 	 * get start of VTOC from the disk label and then search for format1
187 	 * and format8 labels
188 	 */
189 	secperblk = blocksize >> 9;
190 	blk = cchhb2blk(&label->vol.vtoc, geo) + 1;
191 	counter = 0;
192 	data = read_part_sector(state, blk * secperblk, &sect);
193 	while (data != NULL) {
194 		memcpy(&f1, data, sizeof(struct vtoc_format1_label));
195 		put_dev_sector(sect);
196 		/* skip FMT4 / FMT5 / FMT7 labels */
197 		if (f1.DS1FMTID == _ascebc['4']
198 		    || f1.DS1FMTID == _ascebc['5']
199 		    || f1.DS1FMTID == _ascebc['7']
200 		    || f1.DS1FMTID == _ascebc['9']) {
201 			blk++;
202 			data = read_part_sector(state, blk * secperblk, &sect);
203 			continue;
204 		}
205 		/* only FMT1 and 8 labels valid at this point */
206 		if (f1.DS1FMTID != _ascebc['1'] &&
207 		    f1.DS1FMTID != _ascebc['8'])
208 			break;
209 		/* OK, we got valid partition data */
210 		offset = cchh2blk(&f1.DS1EXT1.llimit, geo);
211 		size  = cchh2blk(&f1.DS1EXT1.ulimit, geo) -
212 			offset + geo->sectors;
213 		offset *= secperblk;
214 		size *= secperblk;
215 		if (counter >= state->limit)
216 			break;
217 		put_partition(state, counter + 1, offset, size);
218 		counter++;
219 		blk++;
220 		data = read_part_sector(state, blk * secperblk, &sect);
221 	}
222 	strlcat(state->pp_buf, "\n", PAGE_SIZE);
223 
224 	if (!data)
225 		return -1;
226 
227 	return 1;
228 }
229 
230 static int find_lnx1_partitions(struct parsed_partitions *state,
231 				struct hd_geometry *geo,
232 				int blocksize,
233 				char name[],
234 				union label_t *label,
235 				sector_t labelsect,
236 				sector_t nr_sectors,
237 				dasd_information2_t *info)
238 {
239 	loff_t offset, geo_size, size;
240 	char tmp[64];
241 	int secperblk;
242 
243 	snprintf(tmp, sizeof(tmp), "LNX1/%8s:", name);
244 	strlcat(state->pp_buf, tmp, PAGE_SIZE);
245 	secperblk = blocksize >> 9;
246 	if (label->lnx.ldl_version == 0xf2) {
247 		size = label->lnx.formatted_blocks * secperblk;
248 	} else {
249 		/*
250 		 * Formated w/o large volume support. If the sanity check
251 		 * 'size based on geo == size based on nr_sectors' is true, then
252 		 * we can safely assume that we know the formatted size of
253 		 * the disk, otherwise we need additional information
254 		 * that we can only get from a real DASD device.
255 		 */
256 		geo_size = geo->cylinders * geo->heads
257 			* geo->sectors * secperblk;
258 		size = nr_sectors;
259 		if (size != geo_size) {
260 			if (!info) {
261 				strlcat(state->pp_buf, "\n", PAGE_SIZE);
262 				return 1;
263 			}
264 			if (!strcmp(info->type, "ECKD"))
265 				if (geo_size < size)
266 					size = geo_size;
267 			/* else keep size based on nr_sectors */
268 		}
269 	}
270 	/* first and only partition starts in the first block after the label */
271 	offset = labelsect + secperblk;
272 	put_partition(state, 1, offset, size - offset);
273 	strlcat(state->pp_buf, "\n", PAGE_SIZE);
274 	return 1;
275 }
276 
277 static int find_cms1_partitions(struct parsed_partitions *state,
278 				struct hd_geometry *geo,
279 				int blocksize,
280 				char name[],
281 				union label_t *label,
282 				sector_t labelsect)
283 {
284 	loff_t offset, size;
285 	char tmp[64];
286 	int secperblk;
287 
288 	/*
289 	 * VM style CMS1 labeled disk
290 	 */
291 	blocksize = label->cms.block_size;
292 	secperblk = blocksize >> 9;
293 	if (label->cms.disk_offset != 0) {
294 		snprintf(tmp, sizeof(tmp), "CMS1/%8s(MDSK):", name);
295 		strlcat(state->pp_buf, tmp, PAGE_SIZE);
296 		/* disk is reserved minidisk */
297 		offset = label->cms.disk_offset * secperblk;
298 		size = (label->cms.block_count - 1) * secperblk;
299 	} else {
300 		snprintf(tmp, sizeof(tmp), "CMS1/%8s:", name);
301 		strlcat(state->pp_buf, tmp, PAGE_SIZE);
302 		/*
303 		 * Special case for FBA devices:
304 		 * If an FBA device is CMS formatted with blocksize > 512 byte
305 		 * and the DIAG discipline is used, then the CMS label is found
306 		 * in sector 1 instead of block 1. However, the partition is
307 		 * still supposed to start in block 2.
308 		 */
309 		if (labelsect == 1)
310 			offset = 2 * secperblk;
311 		else
312 			offset = labelsect + secperblk;
313 		size = label->cms.block_count * secperblk;
314 	}
315 
316 	put_partition(state, 1, offset, size-offset);
317 	strlcat(state->pp_buf, "\n", PAGE_SIZE);
318 	return 1;
319 }
320 
321 
322 /*
323  * This is the main function, called by check.c
324  */
325 int ibm_partition(struct parsed_partitions *state)
326 {
327 	int (*fn)(struct gendisk *disk, dasd_information2_t *info);
328 	struct gendisk *disk = state->disk;
329 	struct block_device *bdev = disk->part0;
330 	int blocksize, res;
331 	loff_t offset, size;
332 	sector_t nr_sectors;
333 	dasd_information2_t *info;
334 	struct hd_geometry *geo;
335 	char type[DASD_VOL_TYPE_LEN + 1] = "";
336 	char name[DASD_VOL_ID_LEN + 1] = "";
337 	sector_t labelsect;
338 	union label_t *label;
339 
340 	res = 0;
341 	if (!disk->fops->getgeo)
342 		goto out_exit;
343 	fn = symbol_get(dasd_biodasdinfo);
344 	blocksize = bdev_logical_block_size(bdev);
345 	if (blocksize <= 0)
346 		goto out_symbol;
347 	nr_sectors = bdev_nr_sectors(bdev);
348 	if (nr_sectors == 0)
349 		goto out_symbol;
350 	info = kmalloc(sizeof(dasd_information2_t), GFP_KERNEL);
351 	if (info == NULL)
352 		goto out_symbol;
353 	geo = kmalloc(sizeof(struct hd_geometry), GFP_KERNEL);
354 	if (geo == NULL)
355 		goto out_nogeo;
356 	label = kmalloc(sizeof(union label_t), GFP_KERNEL);
357 	if (label == NULL)
358 		goto out_nolab;
359 	/* set start if not filled by getgeo function e.g. virtblk */
360 	geo->start = get_start_sect(bdev);
361 	if (disk->fops->getgeo(bdev, geo))
362 		goto out_freeall;
363 	if (!fn || fn(disk, info)) {
364 		kfree(info);
365 		info = NULL;
366 	}
367 
368 	if (find_label(state, info, geo, blocksize, &labelsect, name, type, label)) {
369 		switch (get_label_by_type(type)) {
370 		case DASD_VOLLBL_TYPE_VOL1:
371 			res = find_vol1_partitions(state, geo, blocksize, name,
372 						   label);
373 			break;
374 		case DASD_VOLLBL_TYPE_LNX1:
375 			res = find_lnx1_partitions(state, geo, blocksize, name,
376 						   label, labelsect, nr_sectors,
377 						   info);
378 			break;
379 		case DASD_VOLLBL_TYPE_CMS1:
380 			res = find_cms1_partitions(state, geo, blocksize, name,
381 						   label, labelsect);
382 			break;
383 		}
384 	} else if (info) {
385 		/*
386 		 * ugly but needed for backward compatibility:
387 		 * If the block device is a DASD (i.e. BIODASDINFO2 works),
388 		 * then we claim it in any case, even though it has no valid
389 		 * label. If it has the LDL format, then we simply define a
390 		 * partition as if it had an LNX1 label.
391 		 */
392 		res = 1;
393 		if (info->format == DASD_FORMAT_LDL) {
394 			strlcat(state->pp_buf, "(nonl)", PAGE_SIZE);
395 			size = nr_sectors;
396 			offset = (info->label_block + 1) * (blocksize >> 9);
397 			put_partition(state, 1, offset, size-offset);
398 			strlcat(state->pp_buf, "\n", PAGE_SIZE);
399 		}
400 	} else
401 		res = 0;
402 
403 out_freeall:
404 	kfree(label);
405 out_nolab:
406 	kfree(geo);
407 out_nogeo:
408 	kfree(info);
409 out_symbol:
410 	if (fn)
411 		symbol_put(dasd_biodasdinfo);
412 out_exit:
413 	return res;
414 }
415