xref: /openbmc/linux/arch/powerpc/kernel/nvram_64.c (revision e6f6390a)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  c 2001 PPC 64 Team, IBM Corp
4  *
5  * /dev/nvram driver for PPC64
6  */
7 
8 #include <linux/types.h>
9 #include <linux/errno.h>
10 #include <linux/fs.h>
11 #include <linux/miscdevice.h>
12 #include <linux/fcntl.h>
13 #include <linux/nvram.h>
14 #include <linux/init.h>
15 #include <linux/slab.h>
16 #include <linux/spinlock.h>
17 #include <linux/kmsg_dump.h>
18 #include <linux/pagemap.h>
19 #include <linux/pstore.h>
20 #include <linux/zlib.h>
21 #include <linux/uaccess.h>
22 #include <linux/of.h>
23 #include <asm/nvram.h>
24 #include <asm/rtas.h>
25 #include <asm/machdep.h>
26 
27 #undef DEBUG_NVRAM
28 
29 #define NVRAM_HEADER_LEN	sizeof(struct nvram_header)
30 #define NVRAM_BLOCK_LEN		NVRAM_HEADER_LEN
31 
32 /* If change this size, then change the size of NVNAME_LEN */
33 struct nvram_header {
34 	unsigned char signature;
35 	unsigned char checksum;
36 	unsigned short length;
37 	/* Terminating null required only for names < 12 chars. */
38 	char name[12];
39 };
40 
41 struct nvram_partition {
42 	struct list_head partition;
43 	struct nvram_header header;
44 	unsigned int index;
45 };
46 
47 static LIST_HEAD(nvram_partitions);
48 
49 #ifdef CONFIG_PPC_PSERIES
50 struct nvram_os_partition rtas_log_partition = {
51 	.name = "ibm,rtas-log",
52 	.req_size = 2079,
53 	.min_size = 1055,
54 	.index = -1,
55 	.os_partition = true
56 };
57 #endif
58 
59 struct nvram_os_partition oops_log_partition = {
60 	.name = "lnx,oops-log",
61 	.req_size = 4000,
62 	.min_size = 2000,
63 	.index = -1,
64 	.os_partition = true
65 };
66 
67 static const char *nvram_os_partitions[] = {
68 #ifdef CONFIG_PPC_PSERIES
69 	"ibm,rtas-log",
70 #endif
71 	"lnx,oops-log",
72 	NULL
73 };
74 
75 static void oops_to_nvram(struct kmsg_dumper *dumper,
76 			  enum kmsg_dump_reason reason);
77 
78 static struct kmsg_dumper nvram_kmsg_dumper = {
79 	.dump = oops_to_nvram
80 };
81 
82 /*
83  * For capturing and compressing an oops or panic report...
84 
85  * big_oops_buf[] holds the uncompressed text we're capturing.
86  *
87  * oops_buf[] holds the compressed text, preceded by a oops header.
88  * oops header has u16 holding the version of oops header (to differentiate
89  * between old and new format header) followed by u16 holding the length of
90  * the compressed* text (*Or uncompressed, if compression fails.) and u64
91  * holding the timestamp. oops_buf[] gets written to NVRAM.
92  *
93  * oops_log_info points to the header. oops_data points to the compressed text.
94  *
95  * +- oops_buf
96  * |                                   +- oops_data
97  * v                                   v
98  * +-----------+-----------+-----------+------------------------+
99  * | version   | length    | timestamp | text                   |
100  * | (2 bytes) | (2 bytes) | (8 bytes) | (oops_data_sz bytes)   |
101  * +-----------+-----------+-----------+------------------------+
102  * ^
103  * +- oops_log_info
104  *
105  * We preallocate these buffers during init to avoid kmalloc during oops/panic.
106  */
107 static size_t big_oops_buf_sz;
108 static char *big_oops_buf, *oops_buf;
109 static char *oops_data;
110 static size_t oops_data_sz;
111 
112 /* Compression parameters */
113 #define COMPR_LEVEL 6
114 #define WINDOW_BITS 12
115 #define MEM_LEVEL 4
116 static struct z_stream_s stream;
117 
118 #ifdef CONFIG_PSTORE
119 #ifdef CONFIG_PPC_POWERNV
120 static struct nvram_os_partition skiboot_partition = {
121 	.name = "ibm,skiboot",
122 	.index = -1,
123 	.os_partition = false
124 };
125 #endif
126 
127 #ifdef CONFIG_PPC_PSERIES
128 static struct nvram_os_partition of_config_partition = {
129 	.name = "of-config",
130 	.index = -1,
131 	.os_partition = false
132 };
133 #endif
134 
135 static struct nvram_os_partition common_partition = {
136 	.name = "common",
137 	.index = -1,
138 	.os_partition = false
139 };
140 
141 static enum pstore_type_id nvram_type_ids[] = {
142 	PSTORE_TYPE_DMESG,
143 	PSTORE_TYPE_PPC_COMMON,
144 	-1,
145 	-1,
146 	-1
147 };
148 static int read_type;
149 #endif
150 
151 /* nvram_write_os_partition
152  *
153  * We need to buffer the error logs into nvram to ensure that we have
154  * the failure information to decode.  If we have a severe error there
155  * is no way to guarantee that the OS or the machine is in a state to
156  * get back to user land and write the error to disk.  For example if
157  * the SCSI device driver causes a Machine Check by writing to a bad
158  * IO address, there is no way of guaranteeing that the device driver
159  * is in any state that is would also be able to write the error data
160  * captured to disk, thus we buffer it in NVRAM for analysis on the
161  * next boot.
162  *
163  * In NVRAM the partition containing the error log buffer will looks like:
164  * Header (in bytes):
165  * +-----------+----------+--------+------------+------------------+
166  * | signature | checksum | length | name       | data             |
167  * |0          |1         |2      3|4         15|16        length-1|
168  * +-----------+----------+--------+------------+------------------+
169  *
170  * The 'data' section would look like (in bytes):
171  * +--------------+------------+-----------------------------------+
172  * | event_logged | sequence # | error log                         |
173  * |0            3|4          7|8                  error_log_size-1|
174  * +--------------+------------+-----------------------------------+
175  *
176  * event_logged: 0 if event has not been logged to syslog, 1 if it has
177  * sequence #: The unique sequence # for each event. (until it wraps)
178  * error log: The error log from event_scan
179  */
nvram_write_os_partition(struct nvram_os_partition * part,char * buff,int length,unsigned int err_type,unsigned int error_log_cnt)180 int nvram_write_os_partition(struct nvram_os_partition *part,
181 			     char *buff, int length,
182 			     unsigned int err_type,
183 			     unsigned int error_log_cnt)
184 {
185 	int rc;
186 	loff_t tmp_index;
187 	struct err_log_info info;
188 
189 	if (part->index == -1)
190 		return -ESPIPE;
191 
192 	if (length > part->size)
193 		length = part->size;
194 
195 	info.error_type = cpu_to_be32(err_type);
196 	info.seq_num = cpu_to_be32(error_log_cnt);
197 
198 	tmp_index = part->index;
199 
200 	rc = ppc_md.nvram_write((char *)&info, sizeof(info), &tmp_index);
201 	if (rc <= 0) {
202 		pr_err("%s: Failed nvram_write (%d)\n", __func__, rc);
203 		return rc;
204 	}
205 
206 	rc = ppc_md.nvram_write(buff, length, &tmp_index);
207 	if (rc <= 0) {
208 		pr_err("%s: Failed nvram_write (%d)\n", __func__, rc);
209 		return rc;
210 	}
211 
212 	return 0;
213 }
214 
215 /* nvram_read_partition
216  *
217  * Reads nvram partition for at most 'length'
218  */
nvram_read_partition(struct nvram_os_partition * part,char * buff,int length,unsigned int * err_type,unsigned int * error_log_cnt)219 int nvram_read_partition(struct nvram_os_partition *part, char *buff,
220 			 int length, unsigned int *err_type,
221 			 unsigned int *error_log_cnt)
222 {
223 	int rc;
224 	loff_t tmp_index;
225 	struct err_log_info info;
226 
227 	if (part->index == -1)
228 		return -1;
229 
230 	if (length > part->size)
231 		length = part->size;
232 
233 	tmp_index = part->index;
234 
235 	if (part->os_partition) {
236 		rc = ppc_md.nvram_read((char *)&info, sizeof(info), &tmp_index);
237 		if (rc <= 0) {
238 			pr_err("%s: Failed nvram_read (%d)\n", __func__, rc);
239 			return rc;
240 		}
241 	}
242 
243 	rc = ppc_md.nvram_read(buff, length, &tmp_index);
244 	if (rc <= 0) {
245 		pr_err("%s: Failed nvram_read (%d)\n", __func__, rc);
246 		return rc;
247 	}
248 
249 	if (part->os_partition) {
250 		*error_log_cnt = be32_to_cpu(info.seq_num);
251 		*err_type = be32_to_cpu(info.error_type);
252 	}
253 
254 	return 0;
255 }
256 
257 /* nvram_init_os_partition
258  *
259  * This sets up a partition with an "OS" signature.
260  *
261  * The general strategy is the following:
262  * 1.) If a partition with the indicated name already exists...
263  *	- If it's large enough, use it.
264  *	- Otherwise, recycle it and keep going.
265  * 2.) Search for a free partition that is large enough.
266  * 3.) If there's not a free partition large enough, recycle any obsolete
267  * OS partitions and try again.
268  * 4.) Will first try getting a chunk that will satisfy the requested size.
269  * 5.) If a chunk of the requested size cannot be allocated, then try finding
270  * a chunk that will satisfy the minum needed.
271  *
272  * Returns 0 on success, else -1.
273  */
nvram_init_os_partition(struct nvram_os_partition * part)274 int __init nvram_init_os_partition(struct nvram_os_partition *part)
275 {
276 	loff_t p;
277 	int size;
278 
279 	/* Look for ours */
280 	p = nvram_find_partition(part->name, NVRAM_SIG_OS, &size);
281 
282 	/* Found one but too small, remove it */
283 	if (p && size < part->min_size) {
284 		pr_info("nvram: Found too small %s partition,"
285 					" removing it...\n", part->name);
286 		nvram_remove_partition(part->name, NVRAM_SIG_OS, NULL);
287 		p = 0;
288 	}
289 
290 	/* Create one if we didn't find */
291 	if (!p) {
292 		p = nvram_create_partition(part->name, NVRAM_SIG_OS,
293 					part->req_size, part->min_size);
294 		if (p == -ENOSPC) {
295 			pr_info("nvram: No room to create %s partition, "
296 				"deleting any obsolete OS partitions...\n",
297 				part->name);
298 			nvram_remove_partition(NULL, NVRAM_SIG_OS,
299 					nvram_os_partitions);
300 			p = nvram_create_partition(part->name, NVRAM_SIG_OS,
301 					part->req_size, part->min_size);
302 		}
303 	}
304 
305 	if (p <= 0) {
306 		pr_err("nvram: Failed to find or create %s"
307 		       " partition, err %d\n", part->name, (int)p);
308 		return -1;
309 	}
310 
311 	part->index = p;
312 	part->size = nvram_get_partition_size(p) - sizeof(struct err_log_info);
313 
314 	return 0;
315 }
316 
317 /* Derived from logfs_compress() */
nvram_compress(const void * in,void * out,size_t inlen,size_t outlen)318 static int nvram_compress(const void *in, void *out, size_t inlen,
319 							size_t outlen)
320 {
321 	int err, ret;
322 
323 	ret = -EIO;
324 	err = zlib_deflateInit2(&stream, COMPR_LEVEL, Z_DEFLATED, WINDOW_BITS,
325 						MEM_LEVEL, Z_DEFAULT_STRATEGY);
326 	if (err != Z_OK)
327 		goto error;
328 
329 	stream.next_in = in;
330 	stream.avail_in = inlen;
331 	stream.total_in = 0;
332 	stream.next_out = out;
333 	stream.avail_out = outlen;
334 	stream.total_out = 0;
335 
336 	err = zlib_deflate(&stream, Z_FINISH);
337 	if (err != Z_STREAM_END)
338 		goto error;
339 
340 	err = zlib_deflateEnd(&stream);
341 	if (err != Z_OK)
342 		goto error;
343 
344 	if (stream.total_out >= stream.total_in)
345 		goto error;
346 
347 	ret = stream.total_out;
348 error:
349 	return ret;
350 }
351 
352 /* Compress the text from big_oops_buf into oops_buf. */
zip_oops(size_t text_len)353 static int zip_oops(size_t text_len)
354 {
355 	struct oops_log_info *oops_hdr = (struct oops_log_info *)oops_buf;
356 	int zipped_len = nvram_compress(big_oops_buf, oops_data, text_len,
357 								oops_data_sz);
358 	if (zipped_len < 0) {
359 		pr_err("nvram: compression failed; returned %d\n", zipped_len);
360 		pr_err("nvram: logging uncompressed oops/panic report\n");
361 		return -1;
362 	}
363 	oops_hdr->version = cpu_to_be16(OOPS_HDR_VERSION);
364 	oops_hdr->report_length = cpu_to_be16(zipped_len);
365 	oops_hdr->timestamp = cpu_to_be64(ktime_get_real_seconds());
366 	return 0;
367 }
368 
369 #ifdef CONFIG_PSTORE
nvram_pstore_open(struct pstore_info * psi)370 static int nvram_pstore_open(struct pstore_info *psi)
371 {
372 	/* Reset the iterator to start reading partitions again */
373 	read_type = -1;
374 	return 0;
375 }
376 
377 /**
378  * nvram_pstore_write - pstore write callback for nvram
379  * @record:             pstore record to write, with @id to be set
380  *
381  * Called by pstore_dump() when an oops or panic report is logged in the
382  * printk buffer.
383  * Returns 0 on successful write.
384  */
nvram_pstore_write(struct pstore_record * record)385 static int nvram_pstore_write(struct pstore_record *record)
386 {
387 	int rc;
388 	unsigned int err_type = ERR_TYPE_KERNEL_PANIC;
389 	struct oops_log_info *oops_hdr = (struct oops_log_info *) oops_buf;
390 
391 	/* part 1 has the recent messages from printk buffer */
392 	if (record->part > 1 || (record->type != PSTORE_TYPE_DMESG))
393 		return -1;
394 
395 	if (clobbering_unread_rtas_event())
396 		return -1;
397 
398 	oops_hdr->version = cpu_to_be16(OOPS_HDR_VERSION);
399 	oops_hdr->report_length = cpu_to_be16(record->size);
400 	oops_hdr->timestamp = cpu_to_be64(ktime_get_real_seconds());
401 
402 	if (record->compressed)
403 		err_type = ERR_TYPE_KERNEL_PANIC_GZ;
404 
405 	rc = nvram_write_os_partition(&oops_log_partition, oops_buf,
406 		(int) (sizeof(*oops_hdr) + record->size), err_type,
407 		record->count);
408 
409 	if (rc != 0)
410 		return rc;
411 
412 	record->id = record->part;
413 	return 0;
414 }
415 
416 /*
417  * Reads the oops/panic report, rtas, of-config and common partition.
418  * Returns the length of the data we read from each partition.
419  * Returns 0 if we've been called before.
420  */
nvram_pstore_read(struct pstore_record * record)421 static ssize_t nvram_pstore_read(struct pstore_record *record)
422 {
423 	struct oops_log_info *oops_hdr;
424 	unsigned int err_type, id_no, size = 0;
425 	struct nvram_os_partition *part = NULL;
426 	char *buff = NULL;
427 	int sig = 0;
428 	loff_t p;
429 
430 	read_type++;
431 
432 	switch (nvram_type_ids[read_type]) {
433 	case PSTORE_TYPE_DMESG:
434 		part = &oops_log_partition;
435 		record->type = PSTORE_TYPE_DMESG;
436 		break;
437 	case PSTORE_TYPE_PPC_COMMON:
438 		sig = NVRAM_SIG_SYS;
439 		part = &common_partition;
440 		record->type = PSTORE_TYPE_PPC_COMMON;
441 		record->id = PSTORE_TYPE_PPC_COMMON;
442 		record->time.tv_sec = 0;
443 		record->time.tv_nsec = 0;
444 		break;
445 #ifdef CONFIG_PPC_PSERIES
446 	case PSTORE_TYPE_PPC_RTAS:
447 		part = &rtas_log_partition;
448 		record->type = PSTORE_TYPE_PPC_RTAS;
449 		record->time.tv_sec = last_rtas_event;
450 		record->time.tv_nsec = 0;
451 		break;
452 	case PSTORE_TYPE_PPC_OF:
453 		sig = NVRAM_SIG_OF;
454 		part = &of_config_partition;
455 		record->type = PSTORE_TYPE_PPC_OF;
456 		record->id = PSTORE_TYPE_PPC_OF;
457 		record->time.tv_sec = 0;
458 		record->time.tv_nsec = 0;
459 		break;
460 #endif
461 #ifdef CONFIG_PPC_POWERNV
462 	case PSTORE_TYPE_PPC_OPAL:
463 		sig = NVRAM_SIG_FW;
464 		part = &skiboot_partition;
465 		record->type = PSTORE_TYPE_PPC_OPAL;
466 		record->id = PSTORE_TYPE_PPC_OPAL;
467 		record->time.tv_sec = 0;
468 		record->time.tv_nsec = 0;
469 		break;
470 #endif
471 	default:
472 		return 0;
473 	}
474 
475 	if (!part->os_partition) {
476 		p = nvram_find_partition(part->name, sig, &size);
477 		if (p <= 0) {
478 			pr_err("nvram: Failed to find partition %s, "
479 				"err %d\n", part->name, (int)p);
480 			return 0;
481 		}
482 		part->index = p;
483 		part->size = size;
484 	}
485 
486 	buff = kmalloc(part->size, GFP_KERNEL);
487 
488 	if (!buff)
489 		return -ENOMEM;
490 
491 	if (nvram_read_partition(part, buff, part->size, &err_type, &id_no)) {
492 		kfree(buff);
493 		return 0;
494 	}
495 
496 	record->count = 0;
497 
498 	if (part->os_partition)
499 		record->id = id_no;
500 
501 	if (nvram_type_ids[read_type] == PSTORE_TYPE_DMESG) {
502 		size_t length, hdr_size;
503 
504 		oops_hdr = (struct oops_log_info *)buff;
505 		if (be16_to_cpu(oops_hdr->version) < OOPS_HDR_VERSION) {
506 			/* Old format oops header had 2-byte record size */
507 			hdr_size = sizeof(u16);
508 			length = be16_to_cpu(oops_hdr->version);
509 			record->time.tv_sec = 0;
510 			record->time.tv_nsec = 0;
511 		} else {
512 			hdr_size = sizeof(*oops_hdr);
513 			length = be16_to_cpu(oops_hdr->report_length);
514 			record->time.tv_sec = be64_to_cpu(oops_hdr->timestamp);
515 			record->time.tv_nsec = 0;
516 		}
517 		record->buf = kmemdup(buff + hdr_size, length, GFP_KERNEL);
518 		kfree(buff);
519 		if (record->buf == NULL)
520 			return -ENOMEM;
521 
522 		record->ecc_notice_size = 0;
523 		if (err_type == ERR_TYPE_KERNEL_PANIC_GZ)
524 			record->compressed = true;
525 		else
526 			record->compressed = false;
527 		return length;
528 	}
529 
530 	record->buf = buff;
531 	return part->size;
532 }
533 
534 static struct pstore_info nvram_pstore_info = {
535 	.owner = THIS_MODULE,
536 	.name = "nvram",
537 	.flags = PSTORE_FLAGS_DMESG,
538 	.open = nvram_pstore_open,
539 	.read = nvram_pstore_read,
540 	.write = nvram_pstore_write,
541 };
542 
nvram_pstore_init(void)543 static int __init nvram_pstore_init(void)
544 {
545 	int rc = 0;
546 
547 	if (machine_is(pseries)) {
548 		nvram_type_ids[2] = PSTORE_TYPE_PPC_RTAS;
549 		nvram_type_ids[3] = PSTORE_TYPE_PPC_OF;
550 	} else
551 		nvram_type_ids[2] = PSTORE_TYPE_PPC_OPAL;
552 
553 	nvram_pstore_info.buf = oops_data;
554 	nvram_pstore_info.bufsize = oops_data_sz;
555 
556 	rc = pstore_register(&nvram_pstore_info);
557 	if (rc && (rc != -EPERM))
558 		/* Print error only when pstore.backend == nvram */
559 		pr_err("nvram: pstore_register() failed, returned %d. "
560 				"Defaults to kmsg_dump\n", rc);
561 
562 	return rc;
563 }
564 #else
nvram_pstore_init(void)565 static int __init nvram_pstore_init(void)
566 {
567 	return -1;
568 }
569 #endif
570 
nvram_init_oops_partition(int rtas_partition_exists)571 void __init nvram_init_oops_partition(int rtas_partition_exists)
572 {
573 	int rc;
574 
575 	rc = nvram_init_os_partition(&oops_log_partition);
576 	if (rc != 0) {
577 #ifdef CONFIG_PPC_PSERIES
578 		if (!rtas_partition_exists) {
579 			pr_err("nvram: Failed to initialize oops partition!");
580 			return;
581 		}
582 		pr_notice("nvram: Using %s partition to log both"
583 			" RTAS errors and oops/panic reports\n",
584 			rtas_log_partition.name);
585 		memcpy(&oops_log_partition, &rtas_log_partition,
586 						sizeof(rtas_log_partition));
587 #else
588 		pr_err("nvram: Failed to initialize oops partition!");
589 		return;
590 #endif
591 	}
592 	oops_buf = kmalloc(oops_log_partition.size, GFP_KERNEL);
593 	if (!oops_buf) {
594 		pr_err("nvram: No memory for %s partition\n",
595 						oops_log_partition.name);
596 		return;
597 	}
598 	oops_data = oops_buf + sizeof(struct oops_log_info);
599 	oops_data_sz = oops_log_partition.size - sizeof(struct oops_log_info);
600 
601 	rc = nvram_pstore_init();
602 
603 	if (!rc)
604 		return;
605 
606 	/*
607 	 * Figure compression (preceded by elimination of each line's <n>
608 	 * severity prefix) will reduce the oops/panic report to at most
609 	 * 45% of its original size.
610 	 */
611 	big_oops_buf_sz = (oops_data_sz * 100) / 45;
612 	big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
613 	if (big_oops_buf) {
614 		stream.workspace =  kmalloc(zlib_deflate_workspacesize(
615 					WINDOW_BITS, MEM_LEVEL), GFP_KERNEL);
616 		if (!stream.workspace) {
617 			pr_err("nvram: No memory for compression workspace; "
618 				"skipping compression of %s partition data\n",
619 				oops_log_partition.name);
620 			kfree(big_oops_buf);
621 			big_oops_buf = NULL;
622 		}
623 	} else {
624 		pr_err("No memory for uncompressed %s data; "
625 			"skipping compression\n", oops_log_partition.name);
626 		stream.workspace = NULL;
627 	}
628 
629 	rc = kmsg_dump_register(&nvram_kmsg_dumper);
630 	if (rc != 0) {
631 		pr_err("nvram: kmsg_dump_register() failed; returned %d\n", rc);
632 		kfree(oops_buf);
633 		kfree(big_oops_buf);
634 		kfree(stream.workspace);
635 	}
636 }
637 
638 /*
639  * This is our kmsg_dump callback, called after an oops or panic report
640  * has been written to the printk buffer.  We want to capture as much
641  * of the printk buffer as possible.  First, capture as much as we can
642  * that we think will compress sufficiently to fit in the lnx,oops-log
643  * partition.  If that's too much, go back and capture uncompressed text.
644  */
oops_to_nvram(struct kmsg_dumper * dumper,enum kmsg_dump_reason reason)645 static void oops_to_nvram(struct kmsg_dumper *dumper,
646 			  enum kmsg_dump_reason reason)
647 {
648 	struct oops_log_info *oops_hdr = (struct oops_log_info *)oops_buf;
649 	static unsigned int oops_count = 0;
650 	static struct kmsg_dump_iter iter;
651 	static bool panicking = false;
652 	static DEFINE_SPINLOCK(lock);
653 	unsigned long flags;
654 	size_t text_len;
655 	unsigned int err_type = ERR_TYPE_KERNEL_PANIC_GZ;
656 	int rc = -1;
657 
658 	switch (reason) {
659 	case KMSG_DUMP_SHUTDOWN:
660 		/* These are almost always orderly shutdowns. */
661 		return;
662 	case KMSG_DUMP_OOPS:
663 		break;
664 	case KMSG_DUMP_PANIC:
665 		panicking = true;
666 		break;
667 	case KMSG_DUMP_EMERG:
668 		if (panicking)
669 			/* Panic report already captured. */
670 			return;
671 		break;
672 	default:
673 		pr_err("%s: ignoring unrecognized KMSG_DUMP_* reason %d\n",
674 		       __func__, (int) reason);
675 		return;
676 	}
677 
678 	if (clobbering_unread_rtas_event())
679 		return;
680 
681 	if (!spin_trylock_irqsave(&lock, flags))
682 		return;
683 
684 	if (big_oops_buf) {
685 		kmsg_dump_rewind(&iter);
686 		kmsg_dump_get_buffer(&iter, false,
687 				     big_oops_buf, big_oops_buf_sz, &text_len);
688 		rc = zip_oops(text_len);
689 	}
690 	if (rc != 0) {
691 		kmsg_dump_rewind(&iter);
692 		kmsg_dump_get_buffer(&iter, false,
693 				     oops_data, oops_data_sz, &text_len);
694 		err_type = ERR_TYPE_KERNEL_PANIC;
695 		oops_hdr->version = cpu_to_be16(OOPS_HDR_VERSION);
696 		oops_hdr->report_length = cpu_to_be16(text_len);
697 		oops_hdr->timestamp = cpu_to_be64(ktime_get_real_seconds());
698 	}
699 
700 	(void) nvram_write_os_partition(&oops_log_partition, oops_buf,
701 		(int) (sizeof(*oops_hdr) + text_len), err_type,
702 		++oops_count);
703 
704 	spin_unlock_irqrestore(&lock, flags);
705 }
706 
707 #ifdef DEBUG_NVRAM
nvram_print_partitions(char * label)708 static void __init nvram_print_partitions(char * label)
709 {
710 	struct nvram_partition * tmp_part;
711 
712 	printk(KERN_WARNING "--------%s---------\n", label);
713 	printk(KERN_WARNING "indx\t\tsig\tchks\tlen\tname\n");
714 	list_for_each_entry(tmp_part, &nvram_partitions, partition) {
715 		printk(KERN_WARNING "%4d    \t%02x\t%02x\t%d\t%12.12s\n",
716 		       tmp_part->index, tmp_part->header.signature,
717 		       tmp_part->header.checksum, tmp_part->header.length,
718 		       tmp_part->header.name);
719 	}
720 }
721 #endif
722 
723 
nvram_write_header(struct nvram_partition * part)724 static int __init nvram_write_header(struct nvram_partition * part)
725 {
726 	loff_t tmp_index;
727 	int rc;
728 	struct nvram_header phead;
729 
730 	memcpy(&phead, &part->header, NVRAM_HEADER_LEN);
731 	phead.length = cpu_to_be16(phead.length);
732 
733 	tmp_index = part->index;
734 	rc = ppc_md.nvram_write((char *)&phead, NVRAM_HEADER_LEN, &tmp_index);
735 
736 	return rc;
737 }
738 
739 
nvram_checksum(struct nvram_header * p)740 static unsigned char __init nvram_checksum(struct nvram_header *p)
741 {
742 	unsigned int c_sum, c_sum2;
743 	unsigned short *sp = (unsigned short *)p->name; /* assume 6 shorts */
744 	c_sum = p->signature + p->length + sp[0] + sp[1] + sp[2] + sp[3] + sp[4] + sp[5];
745 
746 	/* The sum may have spilled into the 3rd byte.  Fold it back. */
747 	c_sum = ((c_sum & 0xffff) + (c_sum >> 16)) & 0xffff;
748 	/* The sum cannot exceed 2 bytes.  Fold it into a checksum */
749 	c_sum2 = (c_sum >> 8) + (c_sum << 8);
750 	c_sum = ((c_sum + c_sum2) >> 8) & 0xff;
751 	return c_sum;
752 }
753 
754 /*
755  * Per the criteria passed via nvram_remove_partition(), should this
756  * partition be removed?  1=remove, 0=keep
757  */
nvram_can_remove_partition(struct nvram_partition * part,const char * name,int sig,const char * exceptions[])758 static int __init nvram_can_remove_partition(struct nvram_partition *part,
759 		const char *name, int sig, const char *exceptions[])
760 {
761 	if (part->header.signature != sig)
762 		return 0;
763 	if (name) {
764 		if (strncmp(name, part->header.name, 12))
765 			return 0;
766 	} else if (exceptions) {
767 		const char **except;
768 		for (except = exceptions; *except; except++) {
769 			if (!strncmp(*except, part->header.name, 12))
770 				return 0;
771 		}
772 	}
773 	return 1;
774 }
775 
776 /**
777  * nvram_remove_partition - Remove one or more partitions in nvram
778  * @name: name of the partition to remove, or NULL for a
779  *        signature only match
780  * @sig: signature of the partition(s) to remove
781  * @exceptions: When removing all partitions with a matching signature,
782  *        leave these alone.
783  */
784 
nvram_remove_partition(const char * name,int sig,const char * exceptions[])785 int __init nvram_remove_partition(const char *name, int sig,
786 						const char *exceptions[])
787 {
788 	struct nvram_partition *part, *prev, *tmp;
789 	int rc;
790 
791 	list_for_each_entry(part, &nvram_partitions, partition) {
792 		if (!nvram_can_remove_partition(part, name, sig, exceptions))
793 			continue;
794 
795 		/* Make partition a free partition */
796 		part->header.signature = NVRAM_SIG_FREE;
797 		memset(part->header.name, 'w', 12);
798 		part->header.checksum = nvram_checksum(&part->header);
799 		rc = nvram_write_header(part);
800 		if (rc <= 0) {
801 			printk(KERN_ERR "nvram_remove_partition: nvram_write failed (%d)\n", rc);
802 			return rc;
803 		}
804 	}
805 
806 	/* Merge contiguous ones */
807 	prev = NULL;
808 	list_for_each_entry_safe(part, tmp, &nvram_partitions, partition) {
809 		if (part->header.signature != NVRAM_SIG_FREE) {
810 			prev = NULL;
811 			continue;
812 		}
813 		if (prev) {
814 			prev->header.length += part->header.length;
815 			prev->header.checksum = nvram_checksum(&prev->header);
816 			rc = nvram_write_header(prev);
817 			if (rc <= 0) {
818 				printk(KERN_ERR "nvram_remove_partition: nvram_write failed (%d)\n", rc);
819 				return rc;
820 			}
821 			list_del(&part->partition);
822 			kfree(part);
823 		} else
824 			prev = part;
825 	}
826 
827 	return 0;
828 }
829 
830 /**
831  * nvram_create_partition - Create a partition in nvram
832  * @name: name of the partition to create
833  * @sig: signature of the partition to create
834  * @req_size: size of data to allocate in bytes
835  * @min_size: minimum acceptable size (0 means req_size)
836  *
837  * Returns a negative error code or a positive nvram index
838  * of the beginning of the data area of the newly created
839  * partition. If you provided a min_size smaller than req_size
840  * you need to query for the actual size yourself after the
841  * call using nvram_partition_get_size().
842  */
nvram_create_partition(const char * name,int sig,int req_size,int min_size)843 loff_t __init nvram_create_partition(const char *name, int sig,
844 				     int req_size, int min_size)
845 {
846 	struct nvram_partition *part;
847 	struct nvram_partition *new_part;
848 	struct nvram_partition *free_part = NULL;
849 	static char nv_init_vals[16];
850 	loff_t tmp_index;
851 	long size = 0;
852 	int rc;
853 
854 	BUILD_BUG_ON(NVRAM_BLOCK_LEN != 16);
855 
856 	/* Convert sizes from bytes to blocks */
857 	req_size = ALIGN(req_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;
858 	min_size = ALIGN(min_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;
859 
860 	/* If no minimum size specified, make it the same as the
861 	 * requested size
862 	 */
863 	if (min_size == 0)
864 		min_size = req_size;
865 	if (min_size > req_size)
866 		return -EINVAL;
867 
868 	/* Now add one block to each for the header */
869 	req_size += 1;
870 	min_size += 1;
871 
872 	/* Find a free partition that will give us the maximum needed size
873 	   If can't find one that will give us the minimum size needed */
874 	list_for_each_entry(part, &nvram_partitions, partition) {
875 		if (part->header.signature != NVRAM_SIG_FREE)
876 			continue;
877 
878 		if (part->header.length >= req_size) {
879 			size = req_size;
880 			free_part = part;
881 			break;
882 		}
883 		if (part->header.length > size &&
884 		    part->header.length >= min_size) {
885 			size = part->header.length;
886 			free_part = part;
887 		}
888 	}
889 	if (!size)
890 		return -ENOSPC;
891 
892 	/* Create our OS partition */
893 	new_part = kzalloc(sizeof(*new_part), GFP_KERNEL);
894 	if (!new_part) {
895 		pr_err("%s: kmalloc failed\n", __func__);
896 		return -ENOMEM;
897 	}
898 
899 	new_part->index = free_part->index;
900 	new_part->header.signature = sig;
901 	new_part->header.length = size;
902 	memcpy(new_part->header.name, name, strnlen(name, sizeof(new_part->header.name)));
903 	new_part->header.checksum = nvram_checksum(&new_part->header);
904 
905 	rc = nvram_write_header(new_part);
906 	if (rc <= 0) {
907 		pr_err("%s: nvram_write_header failed (%d)\n", __func__, rc);
908 		kfree(new_part);
909 		return rc;
910 	}
911 	list_add_tail(&new_part->partition, &free_part->partition);
912 
913 	/* Adjust or remove the partition we stole the space from */
914 	if (free_part->header.length > size) {
915 		free_part->index += size * NVRAM_BLOCK_LEN;
916 		free_part->header.length -= size;
917 		free_part->header.checksum = nvram_checksum(&free_part->header);
918 		rc = nvram_write_header(free_part);
919 		if (rc <= 0) {
920 			pr_err("%s: nvram_write_header failed (%d)\n",
921 			       __func__, rc);
922 			return rc;
923 		}
924 	} else {
925 		list_del(&free_part->partition);
926 		kfree(free_part);
927 	}
928 
929 	/* Clear the new partition */
930 	for (tmp_index = new_part->index + NVRAM_HEADER_LEN;
931 	     tmp_index <  ((size - 1) * NVRAM_BLOCK_LEN);
932 	     tmp_index += NVRAM_BLOCK_LEN) {
933 		rc = ppc_md.nvram_write(nv_init_vals, NVRAM_BLOCK_LEN, &tmp_index);
934 		if (rc <= 0) {
935 			pr_err("%s: nvram_write failed (%d)\n",
936 			       __func__, rc);
937 			return rc;
938 		}
939 	}
940 
941 	return new_part->index + NVRAM_HEADER_LEN;
942 }
943 
944 /**
945  * nvram_get_partition_size - Get the data size of an nvram partition
946  * @data_index: This is the offset of the start of the data of
947  *              the partition. The same value that is returned by
948  *              nvram_create_partition().
949  */
nvram_get_partition_size(loff_t data_index)950 int nvram_get_partition_size(loff_t data_index)
951 {
952 	struct nvram_partition *part;
953 
954 	list_for_each_entry(part, &nvram_partitions, partition) {
955 		if (part->index + NVRAM_HEADER_LEN == data_index)
956 			return (part->header.length - 1) * NVRAM_BLOCK_LEN;
957 	}
958 	return -1;
959 }
960 
961 
962 /**
963  * nvram_find_partition - Find an nvram partition by signature and name
964  * @name: Name of the partition or NULL for any name
965  * @sig: Signature to test against
966  * @out_size: if non-NULL, returns the size of the data part of the partition
967  */
nvram_find_partition(const char * name,int sig,int * out_size)968 loff_t nvram_find_partition(const char *name, int sig, int *out_size)
969 {
970 	struct nvram_partition *p;
971 
972 	list_for_each_entry(p, &nvram_partitions, partition) {
973 		if (p->header.signature == sig &&
974 		    (!name || !strncmp(p->header.name, name, 12))) {
975 			if (out_size)
976 				*out_size = (p->header.length - 1) *
977 					NVRAM_BLOCK_LEN;
978 			return p->index + NVRAM_HEADER_LEN;
979 		}
980 	}
981 	return 0;
982 }
983 
nvram_scan_partitions(void)984 int __init nvram_scan_partitions(void)
985 {
986 	loff_t cur_index = 0;
987 	struct nvram_header phead;
988 	struct nvram_partition * tmp_part;
989 	unsigned char c_sum;
990 	char * header;
991 	int total_size;
992 	int err;
993 
994 	if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
995 		return -ENODEV;
996 	total_size = ppc_md.nvram_size();
997 
998 	header = kmalloc(NVRAM_HEADER_LEN, GFP_KERNEL);
999 	if (!header) {
1000 		printk(KERN_ERR "nvram_scan_partitions: Failed kmalloc\n");
1001 		return -ENOMEM;
1002 	}
1003 
1004 	while (cur_index < total_size) {
1005 
1006 		err = ppc_md.nvram_read(header, NVRAM_HEADER_LEN, &cur_index);
1007 		if (err != NVRAM_HEADER_LEN) {
1008 			printk(KERN_ERR "nvram_scan_partitions: Error parsing "
1009 			       "nvram partitions\n");
1010 			goto out;
1011 		}
1012 
1013 		cur_index -= NVRAM_HEADER_LEN; /* nvram_read will advance us */
1014 
1015 		memcpy(&phead, header, NVRAM_HEADER_LEN);
1016 
1017 		phead.length = be16_to_cpu(phead.length);
1018 
1019 		err = 0;
1020 		c_sum = nvram_checksum(&phead);
1021 		if (c_sum != phead.checksum) {
1022 			printk(KERN_WARNING "WARNING: nvram partition checksum"
1023 			       " was %02x, should be %02x!\n",
1024 			       phead.checksum, c_sum);
1025 			printk(KERN_WARNING "Terminating nvram partition scan\n");
1026 			goto out;
1027 		}
1028 		if (!phead.length) {
1029 			printk(KERN_WARNING "WARNING: nvram corruption "
1030 			       "detected: 0-length partition\n");
1031 			goto out;
1032 		}
1033 		tmp_part = kmalloc(sizeof(*tmp_part), GFP_KERNEL);
1034 		err = -ENOMEM;
1035 		if (!tmp_part) {
1036 			printk(KERN_ERR "nvram_scan_partitions: kmalloc failed\n");
1037 			goto out;
1038 		}
1039 
1040 		memcpy(&tmp_part->header, &phead, NVRAM_HEADER_LEN);
1041 		tmp_part->index = cur_index;
1042 		list_add_tail(&tmp_part->partition, &nvram_partitions);
1043 
1044 		cur_index += phead.length * NVRAM_BLOCK_LEN;
1045 	}
1046 	err = 0;
1047 
1048 #ifdef DEBUG_NVRAM
1049 	nvram_print_partitions("NVRAM Partitions");
1050 #endif
1051 
1052  out:
1053 	kfree(header);
1054 	return err;
1055 }
1056