xref: /linux/fs/pstore/ram.c (revision 9f7d35d9f7a184ffb591b090b2cbf63d2d599c02)
1 /*
2  * RAM Oops/Panic logger
3  *
4  * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
5  * Copyright (C) 2011 Kees Cook <keescook@chromium.org>
6  *
7  * This program is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU General Public License
9  * version 2 as published by the Free Software Foundation.
10  *
11  * This program is distributed in the hope that it will be useful, but
12  * WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
19  * 02110-1301 USA
20  *
21  */
22 
23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
24 
25 #include <linux/kernel.h>
26 #include <linux/err.h>
27 #include <linux/module.h>
28 #include <linux/version.h>
29 #include <linux/pstore.h>
30 #include <linux/io.h>
31 #include <linux/ioport.h>
32 #include <linux/platform_device.h>
33 #include <linux/slab.h>
34 #include <linux/compiler.h>
35 #include <linux/pstore_ram.h>
36 #include <linux/of.h>
37 #include <linux/of_address.h>
38 
39 #define RAMOOPS_KERNMSG_HDR "===="
40 #define MIN_MEM_SIZE 4096UL
41 
42 static ulong record_size = MIN_MEM_SIZE;
43 module_param(record_size, ulong, 0400);
44 MODULE_PARM_DESC(record_size,
45 		"size of each dump done on oops/panic");
46 
47 static ulong ramoops_console_size = MIN_MEM_SIZE;
48 module_param_named(console_size, ramoops_console_size, ulong, 0400);
49 MODULE_PARM_DESC(console_size, "size of kernel console log");
50 
51 static ulong ramoops_ftrace_size = MIN_MEM_SIZE;
52 module_param_named(ftrace_size, ramoops_ftrace_size, ulong, 0400);
53 MODULE_PARM_DESC(ftrace_size, "size of ftrace log");
54 
55 static ulong ramoops_pmsg_size = MIN_MEM_SIZE;
56 module_param_named(pmsg_size, ramoops_pmsg_size, ulong, 0400);
57 MODULE_PARM_DESC(pmsg_size, "size of user space message log");
58 
59 static unsigned long long mem_address;
60 module_param_hw(mem_address, ullong, other, 0400);
61 MODULE_PARM_DESC(mem_address,
62 		"start of reserved RAM used to store oops/panic logs");
63 
64 static ulong mem_size;
65 module_param(mem_size, ulong, 0400);
66 MODULE_PARM_DESC(mem_size,
67 		"size of reserved RAM used to store oops/panic logs");
68 
69 static unsigned int mem_type;
70 module_param(mem_type, uint, 0600);
71 MODULE_PARM_DESC(mem_type,
72 		"set to 1 to try to use unbuffered memory (default 0)");
73 
74 static int dump_oops = 1;
75 module_param(dump_oops, int, 0600);
76 MODULE_PARM_DESC(dump_oops,
77 		"set to 1 to dump oopses, 0 to only dump panics (default 1)");
78 
79 static int ramoops_ecc;
80 module_param_named(ecc, ramoops_ecc, int, 0600);
81 MODULE_PARM_DESC(ramoops_ecc,
82 		"if non-zero, the option enables ECC support and specifies "
83 		"ECC buffer size in bytes (1 is a special value, means 16 "
84 		"bytes ECC)");
85 
86 struct ramoops_context {
87 	struct persistent_ram_zone **dprzs;	/* Oops dump zones */
88 	struct persistent_ram_zone *cprz;	/* Console zone */
89 	struct persistent_ram_zone **fprzs;	/* Ftrace zones */
90 	struct persistent_ram_zone *mprz;	/* PMSG zone */
91 	phys_addr_t phys_addr;
92 	unsigned long size;
93 	unsigned int memtype;
94 	size_t record_size;
95 	size_t console_size;
96 	size_t ftrace_size;
97 	size_t pmsg_size;
98 	int dump_oops;
99 	u32 flags;
100 	struct persistent_ram_ecc_info ecc_info;
101 	unsigned int max_dump_cnt;
102 	unsigned int dump_write_cnt;
103 	/* _read_cnt need clear on ramoops_pstore_open */
104 	unsigned int dump_read_cnt;
105 	unsigned int console_read_cnt;
106 	unsigned int max_ftrace_cnt;
107 	unsigned int ftrace_read_cnt;
108 	unsigned int pmsg_read_cnt;
109 	struct pstore_info pstore;
110 };
111 
112 static struct platform_device *dummy;
113 static struct ramoops_platform_data *dummy_data;
114 
115 static int ramoops_pstore_open(struct pstore_info *psi)
116 {
117 	struct ramoops_context *cxt = psi->data;
118 
119 	cxt->dump_read_cnt = 0;
120 	cxt->console_read_cnt = 0;
121 	cxt->ftrace_read_cnt = 0;
122 	cxt->pmsg_read_cnt = 0;
123 	return 0;
124 }
125 
126 static struct persistent_ram_zone *
127 ramoops_get_next_prz(struct persistent_ram_zone *przs[], int id,
128 		     struct pstore_record *record)
129 {
130 	struct persistent_ram_zone *prz;
131 	bool update = (record->type == PSTORE_TYPE_DMESG);
132 
133 	/* Give up if we never existed or have hit the end. */
134 	if (!przs)
135 		return NULL;
136 
137 	prz = przs[id];
138 	if (!prz)
139 		return NULL;
140 
141 	/* Update old/shadowed buffer. */
142 	if (update)
143 		persistent_ram_save_old(prz);
144 
145 	if (!persistent_ram_old_size(prz))
146 		return NULL;
147 
148 	record->type = prz->type;
149 	record->id = id;
150 
151 	return prz;
152 }
153 
154 static int ramoops_read_kmsg_hdr(char *buffer, struct timespec64 *time,
155 				  bool *compressed)
156 {
157 	char data_type;
158 	int header_length = 0;
159 
160 	if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lld.%lu-%c\n%n",
161 		   (time64_t *)&time->tv_sec, &time->tv_nsec, &data_type,
162 		   &header_length) == 3) {
163 		if (data_type == 'C')
164 			*compressed = true;
165 		else
166 			*compressed = false;
167 	} else if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lld.%lu\n%n",
168 			  (time64_t *)&time->tv_sec, &time->tv_nsec,
169 			  &header_length) == 2) {
170 		*compressed = false;
171 	} else {
172 		time->tv_sec = 0;
173 		time->tv_nsec = 0;
174 		*compressed = false;
175 	}
176 	return header_length;
177 }
178 
179 static bool prz_ok(struct persistent_ram_zone *prz)
180 {
181 	return !!prz && !!(persistent_ram_old_size(prz) +
182 			   persistent_ram_ecc_string(prz, NULL, 0));
183 }
184 
185 static ssize_t ftrace_log_combine(struct persistent_ram_zone *dest,
186 				  struct persistent_ram_zone *src)
187 {
188 	size_t dest_size, src_size, total, dest_off, src_off;
189 	size_t dest_idx = 0, src_idx = 0, merged_idx = 0;
190 	void *merged_buf;
191 	struct pstore_ftrace_record *drec, *srec, *mrec;
192 	size_t record_size = sizeof(struct pstore_ftrace_record);
193 
194 	dest_off = dest->old_log_size % record_size;
195 	dest_size = dest->old_log_size - dest_off;
196 
197 	src_off = src->old_log_size % record_size;
198 	src_size = src->old_log_size - src_off;
199 
200 	total = dest_size + src_size;
201 	merged_buf = kmalloc(total, GFP_KERNEL);
202 	if (!merged_buf)
203 		return -ENOMEM;
204 
205 	drec = (struct pstore_ftrace_record *)(dest->old_log + dest_off);
206 	srec = (struct pstore_ftrace_record *)(src->old_log + src_off);
207 	mrec = (struct pstore_ftrace_record *)(merged_buf);
208 
209 	while (dest_size > 0 && src_size > 0) {
210 		if (pstore_ftrace_read_timestamp(&drec[dest_idx]) <
211 		    pstore_ftrace_read_timestamp(&srec[src_idx])) {
212 			mrec[merged_idx++] = drec[dest_idx++];
213 			dest_size -= record_size;
214 		} else {
215 			mrec[merged_idx++] = srec[src_idx++];
216 			src_size -= record_size;
217 		}
218 	}
219 
220 	while (dest_size > 0) {
221 		mrec[merged_idx++] = drec[dest_idx++];
222 		dest_size -= record_size;
223 	}
224 
225 	while (src_size > 0) {
226 		mrec[merged_idx++] = srec[src_idx++];
227 		src_size -= record_size;
228 	}
229 
230 	kfree(dest->old_log);
231 	dest->old_log = merged_buf;
232 	dest->old_log_size = total;
233 
234 	return 0;
235 }
236 
237 static ssize_t ramoops_pstore_read(struct pstore_record *record)
238 {
239 	ssize_t size = 0;
240 	struct ramoops_context *cxt = record->psi->data;
241 	struct persistent_ram_zone *prz = NULL;
242 	int header_length = 0;
243 	bool free_prz = false;
244 
245 	/*
246 	 * Ramoops headers provide time stamps for PSTORE_TYPE_DMESG, but
247 	 * PSTORE_TYPE_CONSOLE and PSTORE_TYPE_FTRACE don't currently have
248 	 * valid time stamps, so it is initialized to zero.
249 	 */
250 	record->time.tv_sec = 0;
251 	record->time.tv_nsec = 0;
252 	record->compressed = false;
253 
254 	/* Find the next valid persistent_ram_zone for DMESG */
255 	while (cxt->dump_read_cnt < cxt->max_dump_cnt && !prz) {
256 		prz = ramoops_get_next_prz(cxt->dprzs, cxt->dump_read_cnt++,
257 					   record);
258 		if (!prz_ok(prz))
259 			continue;
260 		header_length = ramoops_read_kmsg_hdr(persistent_ram_old(prz),
261 						      &record->time,
262 						      &record->compressed);
263 		/* Clear and skip this DMESG record if it has no valid header */
264 		if (!header_length) {
265 			persistent_ram_free_old(prz);
266 			persistent_ram_zap(prz);
267 			prz = NULL;
268 		}
269 	}
270 
271 	if (!prz_ok(prz) && !cxt->console_read_cnt++)
272 		prz = ramoops_get_next_prz(&cxt->cprz, 0 /* single */, record);
273 
274 	if (!prz_ok(prz) && !cxt->pmsg_read_cnt++)
275 		prz = ramoops_get_next_prz(&cxt->mprz, 0 /* single */, record);
276 
277 	/* ftrace is last since it may want to dynamically allocate memory. */
278 	if (!prz_ok(prz)) {
279 		if (!(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU) &&
280 		    !cxt->ftrace_read_cnt++) {
281 			prz = ramoops_get_next_prz(cxt->fprzs, 0 /* single */,
282 						   record);
283 		} else {
284 			/*
285 			 * Build a new dummy record which combines all the
286 			 * per-cpu records including metadata and ecc info.
287 			 */
288 			struct persistent_ram_zone *tmp_prz, *prz_next;
289 
290 			tmp_prz = kzalloc(sizeof(struct persistent_ram_zone),
291 					  GFP_KERNEL);
292 			if (!tmp_prz)
293 				return -ENOMEM;
294 			prz = tmp_prz;
295 			free_prz = true;
296 
297 			while (cxt->ftrace_read_cnt < cxt->max_ftrace_cnt) {
298 				prz_next = ramoops_get_next_prz(cxt->fprzs,
299 						cxt->ftrace_read_cnt++, record);
300 
301 				if (!prz_ok(prz_next))
302 					continue;
303 
304 				tmp_prz->ecc_info = prz_next->ecc_info;
305 				tmp_prz->corrected_bytes +=
306 						prz_next->corrected_bytes;
307 				tmp_prz->bad_blocks += prz_next->bad_blocks;
308 				size = ftrace_log_combine(tmp_prz, prz_next);
309 				if (size)
310 					goto out;
311 			}
312 			record->id = 0;
313 		}
314 	}
315 
316 	if (!prz_ok(prz)) {
317 		size = 0;
318 		goto out;
319 	}
320 
321 	size = persistent_ram_old_size(prz) - header_length;
322 
323 	/* ECC correction notice */
324 	record->ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
325 
326 	record->buf = kmalloc(size + record->ecc_notice_size + 1, GFP_KERNEL);
327 	if (record->buf == NULL) {
328 		size = -ENOMEM;
329 		goto out;
330 	}
331 
332 	memcpy(record->buf, (char *)persistent_ram_old(prz) + header_length,
333 	       size);
334 
335 	persistent_ram_ecc_string(prz, record->buf + size,
336 				  record->ecc_notice_size + 1);
337 
338 out:
339 	if (free_prz) {
340 		kfree(prz->old_log);
341 		kfree(prz);
342 	}
343 
344 	return size;
345 }
346 
347 static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz,
348 				     struct pstore_record *record)
349 {
350 	char *hdr;
351 	size_t len;
352 
353 	hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lld.%06lu-%c\n",
354 		(time64_t)record->time.tv_sec,
355 		record->time.tv_nsec / 1000,
356 		record->compressed ? 'C' : 'D');
357 	WARN_ON_ONCE(!hdr);
358 	len = hdr ? strlen(hdr) : 0;
359 	persistent_ram_write(prz, hdr, len);
360 	kfree(hdr);
361 
362 	return len;
363 }
364 
365 static int notrace ramoops_pstore_write(struct pstore_record *record)
366 {
367 	struct ramoops_context *cxt = record->psi->data;
368 	struct persistent_ram_zone *prz;
369 	size_t size, hlen;
370 
371 	if (record->type == PSTORE_TYPE_CONSOLE) {
372 		if (!cxt->cprz)
373 			return -ENOMEM;
374 		persistent_ram_write(cxt->cprz, record->buf, record->size);
375 		return 0;
376 	} else if (record->type == PSTORE_TYPE_FTRACE) {
377 		int zonenum;
378 
379 		if (!cxt->fprzs)
380 			return -ENOMEM;
381 		/*
382 		 * Choose zone by if we're using per-cpu buffers.
383 		 */
384 		if (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
385 			zonenum = smp_processor_id();
386 		else
387 			zonenum = 0;
388 
389 		persistent_ram_write(cxt->fprzs[zonenum], record->buf,
390 				     record->size);
391 		return 0;
392 	} else if (record->type == PSTORE_TYPE_PMSG) {
393 		pr_warn_ratelimited("PMSG shouldn't call %s\n", __func__);
394 		return -EINVAL;
395 	}
396 
397 	if (record->type != PSTORE_TYPE_DMESG)
398 		return -EINVAL;
399 
400 	/*
401 	 * Out of the various dmesg dump types, ramoops is currently designed
402 	 * to only store crash logs, rather than storing general kernel logs.
403 	 */
404 	if (record->reason != KMSG_DUMP_OOPS &&
405 	    record->reason != KMSG_DUMP_PANIC)
406 		return -EINVAL;
407 
408 	/* Skip Oopes when configured to do so. */
409 	if (record->reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
410 		return -EINVAL;
411 
412 	/*
413 	 * Explicitly only take the first part of any new crash.
414 	 * If our buffer is larger than kmsg_bytes, this can never happen,
415 	 * and if our buffer is smaller than kmsg_bytes, we don't want the
416 	 * report split across multiple records.
417 	 */
418 	if (record->part != 1)
419 		return -ENOSPC;
420 
421 	if (!cxt->dprzs)
422 		return -ENOSPC;
423 
424 	prz = cxt->dprzs[cxt->dump_write_cnt];
425 
426 	/* Build header and append record contents. */
427 	hlen = ramoops_write_kmsg_hdr(prz, record);
428 	size = record->size;
429 	if (size + hlen > prz->buffer_size)
430 		size = prz->buffer_size - hlen;
431 	persistent_ram_write(prz, record->buf, size);
432 
433 	cxt->dump_write_cnt = (cxt->dump_write_cnt + 1) % cxt->max_dump_cnt;
434 
435 	return 0;
436 }
437 
438 static int notrace ramoops_pstore_write_user(struct pstore_record *record,
439 					     const char __user *buf)
440 {
441 	if (record->type == PSTORE_TYPE_PMSG) {
442 		struct ramoops_context *cxt = record->psi->data;
443 
444 		if (!cxt->mprz)
445 			return -ENOMEM;
446 		return persistent_ram_write_user(cxt->mprz, buf, record->size);
447 	}
448 
449 	return -EINVAL;
450 }
451 
452 static int ramoops_pstore_erase(struct pstore_record *record)
453 {
454 	struct ramoops_context *cxt = record->psi->data;
455 	struct persistent_ram_zone *prz;
456 
457 	switch (record->type) {
458 	case PSTORE_TYPE_DMESG:
459 		if (record->id >= cxt->max_dump_cnt)
460 			return -EINVAL;
461 		prz = cxt->dprzs[record->id];
462 		break;
463 	case PSTORE_TYPE_CONSOLE:
464 		prz = cxt->cprz;
465 		break;
466 	case PSTORE_TYPE_FTRACE:
467 		if (record->id >= cxt->max_ftrace_cnt)
468 			return -EINVAL;
469 		prz = cxt->fprzs[record->id];
470 		break;
471 	case PSTORE_TYPE_PMSG:
472 		prz = cxt->mprz;
473 		break;
474 	default:
475 		return -EINVAL;
476 	}
477 
478 	persistent_ram_free_old(prz);
479 	persistent_ram_zap(prz);
480 
481 	return 0;
482 }
483 
484 static struct ramoops_context oops_cxt = {
485 	.pstore = {
486 		.owner	= THIS_MODULE,
487 		.name	= "ramoops",
488 		.open	= ramoops_pstore_open,
489 		.read	= ramoops_pstore_read,
490 		.write	= ramoops_pstore_write,
491 		.write_user	= ramoops_pstore_write_user,
492 		.erase	= ramoops_pstore_erase,
493 	},
494 };
495 
496 static void ramoops_free_przs(struct ramoops_context *cxt)
497 {
498 	int i;
499 
500 	/* Free dump PRZs */
501 	if (cxt->dprzs) {
502 		for (i = 0; i < cxt->max_dump_cnt; i++)
503 			persistent_ram_free(cxt->dprzs[i]);
504 
505 		kfree(cxt->dprzs);
506 		cxt->max_dump_cnt = 0;
507 	}
508 
509 	/* Free ftrace PRZs */
510 	if (cxt->fprzs) {
511 		for (i = 0; i < cxt->max_ftrace_cnt; i++)
512 			persistent_ram_free(cxt->fprzs[i]);
513 		kfree(cxt->fprzs);
514 		cxt->max_ftrace_cnt = 0;
515 	}
516 }
517 
518 static int ramoops_init_przs(const char *name,
519 			     struct device *dev, struct ramoops_context *cxt,
520 			     struct persistent_ram_zone ***przs,
521 			     phys_addr_t *paddr, size_t mem_sz,
522 			     ssize_t record_size,
523 			     unsigned int *cnt, u32 sig, u32 flags)
524 {
525 	int err = -ENOMEM;
526 	int i;
527 	size_t zone_sz;
528 	struct persistent_ram_zone **prz_ar;
529 
530 	/* Allocate nothing for 0 mem_sz or 0 record_size. */
531 	if (mem_sz == 0 || record_size == 0) {
532 		*cnt = 0;
533 		return 0;
534 	}
535 
536 	/*
537 	 * If we have a negative record size, calculate it based on
538 	 * mem_sz / *cnt. If we have a positive record size, calculate
539 	 * cnt from mem_sz / record_size.
540 	 */
541 	if (record_size < 0) {
542 		if (*cnt == 0)
543 			return 0;
544 		record_size = mem_sz / *cnt;
545 		if (record_size == 0) {
546 			dev_err(dev, "%s record size == 0 (%zu / %u)\n",
547 				name, mem_sz, *cnt);
548 			goto fail;
549 		}
550 	} else {
551 		*cnt = mem_sz / record_size;
552 		if (*cnt == 0) {
553 			dev_err(dev, "%s record count == 0 (%zu / %zu)\n",
554 				name, mem_sz, record_size);
555 			goto fail;
556 		}
557 	}
558 
559 	if (*paddr + mem_sz - cxt->phys_addr > cxt->size) {
560 		dev_err(dev, "no room for %s mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
561 			name,
562 			mem_sz, (unsigned long long)*paddr,
563 			cxt->size, (unsigned long long)cxt->phys_addr);
564 		goto fail;
565 	}
566 
567 	zone_sz = mem_sz / *cnt;
568 	if (!zone_sz) {
569 		dev_err(dev, "%s zone size == 0\n", name);
570 		goto fail;
571 	}
572 
573 	prz_ar = kcalloc(*cnt, sizeof(**przs), GFP_KERNEL);
574 	if (!prz_ar)
575 		goto fail;
576 
577 	for (i = 0; i < *cnt; i++) {
578 		char *label;
579 
580 		if (*cnt == 1)
581 			label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
582 		else
583 			label = kasprintf(GFP_KERNEL, "ramoops:%s(%d/%d)",
584 					  name, i, *cnt - 1);
585 		prz_ar[i] = persistent_ram_new(*paddr, zone_sz, sig,
586 					       &cxt->ecc_info,
587 					       cxt->memtype, flags, label);
588 		if (IS_ERR(prz_ar[i])) {
589 			err = PTR_ERR(prz_ar[i]);
590 			dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
591 				name, record_size,
592 				(unsigned long long)*paddr, err);
593 
594 			while (i > 0) {
595 				i--;
596 				persistent_ram_free(prz_ar[i]);
597 			}
598 			kfree(prz_ar);
599 			goto fail;
600 		}
601 		*paddr += zone_sz;
602 		prz_ar[i]->type = pstore_name_to_type(name);
603 	}
604 
605 	*przs = prz_ar;
606 	return 0;
607 
608 fail:
609 	*cnt = 0;
610 	return err;
611 }
612 
613 static int ramoops_init_prz(const char *name,
614 			    struct device *dev, struct ramoops_context *cxt,
615 			    struct persistent_ram_zone **prz,
616 			    phys_addr_t *paddr, size_t sz, u32 sig)
617 {
618 	char *label;
619 
620 	if (!sz)
621 		return 0;
622 
623 	if (*paddr + sz - cxt->phys_addr > cxt->size) {
624 		dev_err(dev, "no room for %s mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
625 			name, sz, (unsigned long long)*paddr,
626 			cxt->size, (unsigned long long)cxt->phys_addr);
627 		return -ENOMEM;
628 	}
629 
630 	label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
631 	*prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info,
632 				  cxt->memtype, PRZ_FLAG_ZAP_OLD, label);
633 	if (IS_ERR(*prz)) {
634 		int err = PTR_ERR(*prz);
635 
636 		dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
637 			name, sz, (unsigned long long)*paddr, err);
638 		return err;
639 	}
640 
641 	*paddr += sz;
642 	(*prz)->type = pstore_name_to_type(name);
643 
644 	return 0;
645 }
646 
647 static int ramoops_parse_dt_size(struct platform_device *pdev,
648 				 const char *propname, u32 *value)
649 {
650 	u32 val32 = 0;
651 	int ret;
652 
653 	ret = of_property_read_u32(pdev->dev.of_node, propname, &val32);
654 	if (ret < 0 && ret != -EINVAL) {
655 		dev_err(&pdev->dev, "failed to parse property %s: %d\n",
656 			propname, ret);
657 		return ret;
658 	}
659 
660 	if (val32 > INT_MAX) {
661 		dev_err(&pdev->dev, "%s %u > INT_MAX\n", propname, val32);
662 		return -EOVERFLOW;
663 	}
664 
665 	*value = val32;
666 	return 0;
667 }
668 
669 static int ramoops_parse_dt(struct platform_device *pdev,
670 			    struct ramoops_platform_data *pdata)
671 {
672 	struct device_node *of_node = pdev->dev.of_node;
673 	struct resource *res;
674 	u32 value;
675 	int ret;
676 
677 	dev_dbg(&pdev->dev, "using Device Tree\n");
678 
679 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
680 	if (!res) {
681 		dev_err(&pdev->dev,
682 			"failed to locate DT /reserved-memory resource\n");
683 		return -EINVAL;
684 	}
685 
686 	pdata->mem_size = resource_size(res);
687 	pdata->mem_address = res->start;
688 	pdata->mem_type = of_property_read_bool(of_node, "unbuffered");
689 	pdata->dump_oops = !of_property_read_bool(of_node, "no-dump-oops");
690 
691 #define parse_size(name, field) {					\
692 		ret = ramoops_parse_dt_size(pdev, name, &value);	\
693 		if (ret < 0)						\
694 			return ret;					\
695 		field = value;						\
696 	}
697 
698 	parse_size("record-size", pdata->record_size);
699 	parse_size("console-size", pdata->console_size);
700 	parse_size("ftrace-size", pdata->ftrace_size);
701 	parse_size("pmsg-size", pdata->pmsg_size);
702 	parse_size("ecc-size", pdata->ecc_info.ecc_size);
703 	parse_size("flags", pdata->flags);
704 
705 #undef parse_size
706 
707 	return 0;
708 }
709 
710 static int ramoops_probe(struct platform_device *pdev)
711 {
712 	struct device *dev = &pdev->dev;
713 	struct ramoops_platform_data *pdata = dev->platform_data;
714 	struct ramoops_context *cxt = &oops_cxt;
715 	size_t dump_mem_sz;
716 	phys_addr_t paddr;
717 	int err = -EINVAL;
718 
719 	if (dev_of_node(dev) && !pdata) {
720 		pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
721 		if (!pdata) {
722 			pr_err("cannot allocate platform data buffer\n");
723 			err = -ENOMEM;
724 			goto fail_out;
725 		}
726 
727 		err = ramoops_parse_dt(pdev, pdata);
728 		if (err < 0)
729 			goto fail_out;
730 	}
731 
732 	/*
733 	 * Only a single ramoops area allowed at a time, so fail extra
734 	 * probes.
735 	 */
736 	if (cxt->max_dump_cnt) {
737 		pr_err("already initialized\n");
738 		goto fail_out;
739 	}
740 
741 	/* Make sure we didn't get bogus platform data pointer. */
742 	if (!pdata) {
743 		pr_err("NULL platform data\n");
744 		goto fail_out;
745 	}
746 
747 	if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size &&
748 			!pdata->ftrace_size && !pdata->pmsg_size)) {
749 		pr_err("The memory size and the record/console size must be "
750 			"non-zero\n");
751 		goto fail_out;
752 	}
753 
754 	if (pdata->record_size && !is_power_of_2(pdata->record_size))
755 		pdata->record_size = rounddown_pow_of_two(pdata->record_size);
756 	if (pdata->console_size && !is_power_of_2(pdata->console_size))
757 		pdata->console_size = rounddown_pow_of_two(pdata->console_size);
758 	if (pdata->ftrace_size && !is_power_of_2(pdata->ftrace_size))
759 		pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
760 	if (pdata->pmsg_size && !is_power_of_2(pdata->pmsg_size))
761 		pdata->pmsg_size = rounddown_pow_of_two(pdata->pmsg_size);
762 
763 	cxt->size = pdata->mem_size;
764 	cxt->phys_addr = pdata->mem_address;
765 	cxt->memtype = pdata->mem_type;
766 	cxt->record_size = pdata->record_size;
767 	cxt->console_size = pdata->console_size;
768 	cxt->ftrace_size = pdata->ftrace_size;
769 	cxt->pmsg_size = pdata->pmsg_size;
770 	cxt->dump_oops = pdata->dump_oops;
771 	cxt->flags = pdata->flags;
772 	cxt->ecc_info = pdata->ecc_info;
773 
774 	paddr = cxt->phys_addr;
775 
776 	dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size
777 			- cxt->pmsg_size;
778 	err = ramoops_init_przs("dmesg", dev, cxt, &cxt->dprzs, &paddr,
779 				dump_mem_sz, cxt->record_size,
780 				&cxt->max_dump_cnt, 0, 0);
781 	if (err)
782 		goto fail_out;
783 
784 	err = ramoops_init_prz("console", dev, cxt, &cxt->cprz, &paddr,
785 			       cxt->console_size, 0);
786 	if (err)
787 		goto fail_init_cprz;
788 
789 	cxt->max_ftrace_cnt = (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
790 				? nr_cpu_ids
791 				: 1;
792 	err = ramoops_init_przs("ftrace", dev, cxt, &cxt->fprzs, &paddr,
793 				cxt->ftrace_size, -1,
794 				&cxt->max_ftrace_cnt, LINUX_VERSION_CODE,
795 				(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
796 					? PRZ_FLAG_NO_LOCK : 0);
797 	if (err)
798 		goto fail_init_fprz;
799 
800 	err = ramoops_init_prz("pmsg", dev, cxt, &cxt->mprz, &paddr,
801 				cxt->pmsg_size, 0);
802 	if (err)
803 		goto fail_init_mprz;
804 
805 	cxt->pstore.data = cxt;
806 	/*
807 	 * Since bufsize is only used for dmesg crash dumps, it
808 	 * must match the size of the dprz record (after PRZ header
809 	 * and ECC bytes have been accounted for).
810 	 */
811 	cxt->pstore.bufsize = cxt->dprzs[0]->buffer_size;
812 	cxt->pstore.buf = kzalloc(cxt->pstore.bufsize, GFP_KERNEL);
813 	if (!cxt->pstore.buf) {
814 		pr_err("cannot allocate pstore crash dump buffer\n");
815 		err = -ENOMEM;
816 		goto fail_clear;
817 	}
818 
819 	cxt->pstore.flags = PSTORE_FLAGS_DMESG;
820 	if (cxt->console_size)
821 		cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE;
822 	if (cxt->ftrace_size)
823 		cxt->pstore.flags |= PSTORE_FLAGS_FTRACE;
824 	if (cxt->pmsg_size)
825 		cxt->pstore.flags |= PSTORE_FLAGS_PMSG;
826 
827 	err = pstore_register(&cxt->pstore);
828 	if (err) {
829 		pr_err("registering with pstore failed\n");
830 		goto fail_buf;
831 	}
832 
833 	/*
834 	 * Update the module parameter variables as well so they are visible
835 	 * through /sys/module/ramoops/parameters/
836 	 */
837 	mem_size = pdata->mem_size;
838 	mem_address = pdata->mem_address;
839 	record_size = pdata->record_size;
840 	dump_oops = pdata->dump_oops;
841 	ramoops_console_size = pdata->console_size;
842 	ramoops_pmsg_size = pdata->pmsg_size;
843 	ramoops_ftrace_size = pdata->ftrace_size;
844 
845 	pr_info("using 0x%lx@0x%llx, ecc: %d\n",
846 		cxt->size, (unsigned long long)cxt->phys_addr,
847 		cxt->ecc_info.ecc_size);
848 
849 	return 0;
850 
851 fail_buf:
852 	kfree(cxt->pstore.buf);
853 fail_clear:
854 	cxt->pstore.bufsize = 0;
855 	persistent_ram_free(cxt->mprz);
856 fail_init_mprz:
857 fail_init_fprz:
858 	persistent_ram_free(cxt->cprz);
859 fail_init_cprz:
860 	ramoops_free_przs(cxt);
861 fail_out:
862 	return err;
863 }
864 
865 static int ramoops_remove(struct platform_device *pdev)
866 {
867 	struct ramoops_context *cxt = &oops_cxt;
868 
869 	pstore_unregister(&cxt->pstore);
870 
871 	kfree(cxt->pstore.buf);
872 	cxt->pstore.bufsize = 0;
873 
874 	persistent_ram_free(cxt->mprz);
875 	persistent_ram_free(cxt->cprz);
876 	ramoops_free_przs(cxt);
877 
878 	return 0;
879 }
880 
881 static const struct of_device_id dt_match[] = {
882 	{ .compatible = "ramoops" },
883 	{}
884 };
885 
886 static struct platform_driver ramoops_driver = {
887 	.probe		= ramoops_probe,
888 	.remove		= ramoops_remove,
889 	.driver		= {
890 		.name		= "ramoops",
891 		.of_match_table	= dt_match,
892 	},
893 };
894 
895 static inline void ramoops_unregister_dummy(void)
896 {
897 	platform_device_unregister(dummy);
898 	dummy = NULL;
899 
900 	kfree(dummy_data);
901 	dummy_data = NULL;
902 }
903 
904 static void __init ramoops_register_dummy(void)
905 {
906 	/*
907 	 * Prepare a dummy platform data structure to carry the module
908 	 * parameters. If mem_size isn't set, then there are no module
909 	 * parameters, and we can skip this.
910 	 */
911 	if (!mem_size)
912 		return;
913 
914 	pr_info("using module parameters\n");
915 
916 	dummy_data = kzalloc(sizeof(*dummy_data), GFP_KERNEL);
917 	if (!dummy_data) {
918 		pr_info("could not allocate pdata\n");
919 		return;
920 	}
921 
922 	dummy_data->mem_size = mem_size;
923 	dummy_data->mem_address = mem_address;
924 	dummy_data->mem_type = mem_type;
925 	dummy_data->record_size = record_size;
926 	dummy_data->console_size = ramoops_console_size;
927 	dummy_data->ftrace_size = ramoops_ftrace_size;
928 	dummy_data->pmsg_size = ramoops_pmsg_size;
929 	dummy_data->dump_oops = dump_oops;
930 	dummy_data->flags = RAMOOPS_FLAG_FTRACE_PER_CPU;
931 
932 	/*
933 	 * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
934 	 * (using 1 byte for ECC isn't much of use anyway).
935 	 */
936 	dummy_data->ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
937 
938 	dummy = platform_device_register_data(NULL, "ramoops", -1,
939 			dummy_data, sizeof(struct ramoops_platform_data));
940 	if (IS_ERR(dummy)) {
941 		pr_info("could not create platform device: %ld\n",
942 			PTR_ERR(dummy));
943 		dummy = NULL;
944 		ramoops_unregister_dummy();
945 	}
946 }
947 
948 static int __init ramoops_init(void)
949 {
950 	int ret;
951 
952 	ramoops_register_dummy();
953 	ret = platform_driver_register(&ramoops_driver);
954 	if (ret != 0)
955 		ramoops_unregister_dummy();
956 
957 	return ret;
958 }
959 postcore_initcall(ramoops_init);
960 
961 static void __exit ramoops_exit(void)
962 {
963 	platform_driver_unregister(&ramoops_driver);
964 	ramoops_unregister_dummy();
965 }
966 module_exit(ramoops_exit);
967 
968 MODULE_LICENSE("GPL");
969 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
970 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");
971