xref: /linux/fs/pstore/ram.c (revision 9bacbced0e32204deb8b9d011279f9beddd8c2ef)
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[], uint *c, uint max,
128 		     u64 *id,
129 		     enum pstore_type_id *typep, enum pstore_type_id type,
130 		     bool update)
131 {
132 	struct persistent_ram_zone *prz;
133 	int i = (*c)++;
134 
135 	/* Give up if we never existed or have hit the end. */
136 	if (!przs || i >= max)
137 		return NULL;
138 
139 	prz = przs[i];
140 	if (!prz)
141 		return NULL;
142 
143 	/* Update old/shadowed buffer. */
144 	if (update)
145 		persistent_ram_save_old(prz);
146 
147 	if (!persistent_ram_old_size(prz))
148 		return NULL;
149 
150 	*typep = type;
151 	*id = i;
152 
153 	return prz;
154 }
155 
156 static int ramoops_read_kmsg_hdr(char *buffer, struct timespec64 *time,
157 				  bool *compressed)
158 {
159 	char data_type;
160 	int header_length = 0;
161 
162 	if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lld.%lu-%c\n%n",
163 		   (time64_t *)&time->tv_sec, &time->tv_nsec, &data_type,
164 		   &header_length) == 3) {
165 		if (data_type == 'C')
166 			*compressed = true;
167 		else
168 			*compressed = false;
169 	} else if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lld.%lu\n%n",
170 			  (time64_t *)&time->tv_sec, &time->tv_nsec,
171 			  &header_length) == 2) {
172 		*compressed = false;
173 	} else {
174 		time->tv_sec = 0;
175 		time->tv_nsec = 0;
176 		*compressed = false;
177 	}
178 	return header_length;
179 }
180 
181 static bool prz_ok(struct persistent_ram_zone *prz)
182 {
183 	return !!prz && !!(persistent_ram_old_size(prz) +
184 			   persistent_ram_ecc_string(prz, NULL, 0));
185 }
186 
187 static ssize_t ftrace_log_combine(struct persistent_ram_zone *dest,
188 				  struct persistent_ram_zone *src)
189 {
190 	size_t dest_size, src_size, total, dest_off, src_off;
191 	size_t dest_idx = 0, src_idx = 0, merged_idx = 0;
192 	void *merged_buf;
193 	struct pstore_ftrace_record *drec, *srec, *mrec;
194 	size_t record_size = sizeof(struct pstore_ftrace_record);
195 
196 	dest_off = dest->old_log_size % record_size;
197 	dest_size = dest->old_log_size - dest_off;
198 
199 	src_off = src->old_log_size % record_size;
200 	src_size = src->old_log_size - src_off;
201 
202 	total = dest_size + src_size;
203 	merged_buf = kmalloc(total, GFP_KERNEL);
204 	if (!merged_buf)
205 		return -ENOMEM;
206 
207 	drec = (struct pstore_ftrace_record *)(dest->old_log + dest_off);
208 	srec = (struct pstore_ftrace_record *)(src->old_log + src_off);
209 	mrec = (struct pstore_ftrace_record *)(merged_buf);
210 
211 	while (dest_size > 0 && src_size > 0) {
212 		if (pstore_ftrace_read_timestamp(&drec[dest_idx]) <
213 		    pstore_ftrace_read_timestamp(&srec[src_idx])) {
214 			mrec[merged_idx++] = drec[dest_idx++];
215 			dest_size -= record_size;
216 		} else {
217 			mrec[merged_idx++] = srec[src_idx++];
218 			src_size -= record_size;
219 		}
220 	}
221 
222 	while (dest_size > 0) {
223 		mrec[merged_idx++] = drec[dest_idx++];
224 		dest_size -= record_size;
225 	}
226 
227 	while (src_size > 0) {
228 		mrec[merged_idx++] = srec[src_idx++];
229 		src_size -= record_size;
230 	}
231 
232 	kfree(dest->old_log);
233 	dest->old_log = merged_buf;
234 	dest->old_log_size = total;
235 
236 	return 0;
237 }
238 
239 static ssize_t ramoops_pstore_read(struct pstore_record *record)
240 {
241 	ssize_t size = 0;
242 	struct ramoops_context *cxt = record->psi->data;
243 	struct persistent_ram_zone *prz = NULL;
244 	int header_length = 0;
245 	bool free_prz = false;
246 
247 	/*
248 	 * Ramoops headers provide time stamps for PSTORE_TYPE_DMESG, but
249 	 * PSTORE_TYPE_CONSOLE and PSTORE_TYPE_FTRACE don't currently have
250 	 * valid time stamps, so it is initialized to zero.
251 	 */
252 	record->time.tv_sec = 0;
253 	record->time.tv_nsec = 0;
254 	record->compressed = false;
255 
256 	/* Find the next valid persistent_ram_zone for DMESG */
257 	while (cxt->dump_read_cnt < cxt->max_dump_cnt && !prz) {
258 		prz = ramoops_get_next_prz(cxt->dprzs, &cxt->dump_read_cnt,
259 					   cxt->max_dump_cnt, &record->id,
260 					   &record->type,
261 					   PSTORE_TYPE_DMESG, 1);
262 		if (!prz_ok(prz))
263 			continue;
264 		header_length = ramoops_read_kmsg_hdr(persistent_ram_old(prz),
265 						      &record->time,
266 						      &record->compressed);
267 		/* Clear and skip this DMESG record if it has no valid header */
268 		if (!header_length) {
269 			persistent_ram_free_old(prz);
270 			persistent_ram_zap(prz);
271 			prz = NULL;
272 		}
273 	}
274 
275 	if (!prz_ok(prz))
276 		prz = ramoops_get_next_prz(&cxt->cprz, &cxt->console_read_cnt,
277 					   1, &record->id, &record->type,
278 					   PSTORE_TYPE_CONSOLE, 0);
279 
280 	if (!prz_ok(prz))
281 		prz = ramoops_get_next_prz(&cxt->mprz, &cxt->pmsg_read_cnt,
282 					   1, &record->id, &record->type,
283 					   PSTORE_TYPE_PMSG, 0);
284 
285 	/* ftrace is last since it may want to dynamically allocate memory. */
286 	if (!prz_ok(prz)) {
287 		if (!(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)) {
288 			prz = ramoops_get_next_prz(cxt->fprzs,
289 					&cxt->ftrace_read_cnt, 1, &record->id,
290 					&record->type, PSTORE_TYPE_FTRACE, 0);
291 		} else {
292 			/*
293 			 * Build a new dummy record which combines all the
294 			 * per-cpu records including metadata and ecc info.
295 			 */
296 			struct persistent_ram_zone *tmp_prz, *prz_next;
297 
298 			tmp_prz = kzalloc(sizeof(struct persistent_ram_zone),
299 					  GFP_KERNEL);
300 			if (!tmp_prz)
301 				return -ENOMEM;
302 			free_prz = true;
303 
304 			while (cxt->ftrace_read_cnt < cxt->max_ftrace_cnt) {
305 				prz_next = ramoops_get_next_prz(cxt->fprzs,
306 						&cxt->ftrace_read_cnt,
307 						cxt->max_ftrace_cnt,
308 						&record->id,
309 						&record->type,
310 						PSTORE_TYPE_FTRACE, 0);
311 
312 				if (!prz_ok(prz_next))
313 					continue;
314 
315 				tmp_prz->ecc_info = prz_next->ecc_info;
316 				tmp_prz->corrected_bytes +=
317 						prz_next->corrected_bytes;
318 				tmp_prz->bad_blocks += prz_next->bad_blocks;
319 				size = ftrace_log_combine(tmp_prz, prz_next);
320 				if (size)
321 					goto out;
322 			}
323 			record->id = 0;
324 			prz = tmp_prz;
325 		}
326 	}
327 
328 	if (!prz_ok(prz)) {
329 		size = 0;
330 		goto out;
331 	}
332 
333 	size = persistent_ram_old_size(prz) - header_length;
334 
335 	/* ECC correction notice */
336 	record->ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
337 
338 	record->buf = kmalloc(size + record->ecc_notice_size + 1, GFP_KERNEL);
339 	if (record->buf == NULL) {
340 		size = -ENOMEM;
341 		goto out;
342 	}
343 
344 	memcpy(record->buf, (char *)persistent_ram_old(prz) + header_length,
345 	       size);
346 
347 	persistent_ram_ecc_string(prz, record->buf + size,
348 				  record->ecc_notice_size + 1);
349 
350 out:
351 	if (free_prz) {
352 		kfree(prz->old_log);
353 		kfree(prz);
354 	}
355 
356 	return size;
357 }
358 
359 static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz,
360 				     struct pstore_record *record)
361 {
362 	char *hdr;
363 	size_t len;
364 
365 	hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lld.%06lu-%c\n",
366 		(time64_t)record->time.tv_sec,
367 		record->time.tv_nsec / 1000,
368 		record->compressed ? 'C' : 'D');
369 	WARN_ON_ONCE(!hdr);
370 	len = hdr ? strlen(hdr) : 0;
371 	persistent_ram_write(prz, hdr, len);
372 	kfree(hdr);
373 
374 	return len;
375 }
376 
377 static int notrace ramoops_pstore_write(struct pstore_record *record)
378 {
379 	struct ramoops_context *cxt = record->psi->data;
380 	struct persistent_ram_zone *prz;
381 	size_t size, hlen;
382 
383 	if (record->type == PSTORE_TYPE_CONSOLE) {
384 		if (!cxt->cprz)
385 			return -ENOMEM;
386 		persistent_ram_write(cxt->cprz, record->buf, record->size);
387 		return 0;
388 	} else if (record->type == PSTORE_TYPE_FTRACE) {
389 		int zonenum;
390 
391 		if (!cxt->fprzs)
392 			return -ENOMEM;
393 		/*
394 		 * Choose zone by if we're using per-cpu buffers.
395 		 */
396 		if (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
397 			zonenum = smp_processor_id();
398 		else
399 			zonenum = 0;
400 
401 		persistent_ram_write(cxt->fprzs[zonenum], record->buf,
402 				     record->size);
403 		return 0;
404 	} else if (record->type == PSTORE_TYPE_PMSG) {
405 		pr_warn_ratelimited("PMSG shouldn't call %s\n", __func__);
406 		return -EINVAL;
407 	}
408 
409 	if (record->type != PSTORE_TYPE_DMESG)
410 		return -EINVAL;
411 
412 	/*
413 	 * Out of the various dmesg dump types, ramoops is currently designed
414 	 * to only store crash logs, rather than storing general kernel logs.
415 	 */
416 	if (record->reason != KMSG_DUMP_OOPS &&
417 	    record->reason != KMSG_DUMP_PANIC)
418 		return -EINVAL;
419 
420 	/* Skip Oopes when configured to do so. */
421 	if (record->reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
422 		return -EINVAL;
423 
424 	/*
425 	 * Explicitly only take the first part of any new crash.
426 	 * If our buffer is larger than kmsg_bytes, this can never happen,
427 	 * and if our buffer is smaller than kmsg_bytes, we don't want the
428 	 * report split across multiple records.
429 	 */
430 	if (record->part != 1)
431 		return -ENOSPC;
432 
433 	if (!cxt->dprzs)
434 		return -ENOSPC;
435 
436 	prz = cxt->dprzs[cxt->dump_write_cnt];
437 
438 	/* Build header and append record contents. */
439 	hlen = ramoops_write_kmsg_hdr(prz, record);
440 	size = record->size;
441 	if (size + hlen > prz->buffer_size)
442 		size = prz->buffer_size - hlen;
443 	persistent_ram_write(prz, record->buf, size);
444 
445 	cxt->dump_write_cnt = (cxt->dump_write_cnt + 1) % cxt->max_dump_cnt;
446 
447 	return 0;
448 }
449 
450 static int notrace ramoops_pstore_write_user(struct pstore_record *record,
451 					     const char __user *buf)
452 {
453 	if (record->type == PSTORE_TYPE_PMSG) {
454 		struct ramoops_context *cxt = record->psi->data;
455 
456 		if (!cxt->mprz)
457 			return -ENOMEM;
458 		return persistent_ram_write_user(cxt->mprz, buf, record->size);
459 	}
460 
461 	return -EINVAL;
462 }
463 
464 static int ramoops_pstore_erase(struct pstore_record *record)
465 {
466 	struct ramoops_context *cxt = record->psi->data;
467 	struct persistent_ram_zone *prz;
468 
469 	switch (record->type) {
470 	case PSTORE_TYPE_DMESG:
471 		if (record->id >= cxt->max_dump_cnt)
472 			return -EINVAL;
473 		prz = cxt->dprzs[record->id];
474 		break;
475 	case PSTORE_TYPE_CONSOLE:
476 		prz = cxt->cprz;
477 		break;
478 	case PSTORE_TYPE_FTRACE:
479 		if (record->id >= cxt->max_ftrace_cnt)
480 			return -EINVAL;
481 		prz = cxt->fprzs[record->id];
482 		break;
483 	case PSTORE_TYPE_PMSG:
484 		prz = cxt->mprz;
485 		break;
486 	default:
487 		return -EINVAL;
488 	}
489 
490 	persistent_ram_free_old(prz);
491 	persistent_ram_zap(prz);
492 
493 	return 0;
494 }
495 
496 static struct ramoops_context oops_cxt = {
497 	.pstore = {
498 		.owner	= THIS_MODULE,
499 		.name	= "ramoops",
500 		.open	= ramoops_pstore_open,
501 		.read	= ramoops_pstore_read,
502 		.write	= ramoops_pstore_write,
503 		.write_user	= ramoops_pstore_write_user,
504 		.erase	= ramoops_pstore_erase,
505 	},
506 };
507 
508 static void ramoops_free_przs(struct ramoops_context *cxt)
509 {
510 	int i;
511 
512 	/* Free dump PRZs */
513 	if (cxt->dprzs) {
514 		for (i = 0; i < cxt->max_dump_cnt; i++)
515 			persistent_ram_free(cxt->dprzs[i]);
516 
517 		kfree(cxt->dprzs);
518 		cxt->max_dump_cnt = 0;
519 	}
520 
521 	/* Free ftrace PRZs */
522 	if (cxt->fprzs) {
523 		for (i = 0; i < cxt->max_ftrace_cnt; i++)
524 			persistent_ram_free(cxt->fprzs[i]);
525 		kfree(cxt->fprzs);
526 		cxt->max_ftrace_cnt = 0;
527 	}
528 }
529 
530 static int ramoops_init_przs(const char *name,
531 			     struct device *dev, struct ramoops_context *cxt,
532 			     struct persistent_ram_zone ***przs,
533 			     phys_addr_t *paddr, size_t mem_sz,
534 			     ssize_t record_size,
535 			     unsigned int *cnt, u32 sig, u32 flags)
536 {
537 	int err = -ENOMEM;
538 	int i;
539 	size_t zone_sz;
540 	struct persistent_ram_zone **prz_ar;
541 
542 	/* Allocate nothing for 0 mem_sz or 0 record_size. */
543 	if (mem_sz == 0 || record_size == 0) {
544 		*cnt = 0;
545 		return 0;
546 	}
547 
548 	/*
549 	 * If we have a negative record size, calculate it based on
550 	 * mem_sz / *cnt. If we have a positive record size, calculate
551 	 * cnt from mem_sz / record_size.
552 	 */
553 	if (record_size < 0) {
554 		if (*cnt == 0)
555 			return 0;
556 		record_size = mem_sz / *cnt;
557 		if (record_size == 0) {
558 			dev_err(dev, "%s record size == 0 (%zu / %u)\n",
559 				name, mem_sz, *cnt);
560 			goto fail;
561 		}
562 	} else {
563 		*cnt = mem_sz / record_size;
564 		if (*cnt == 0) {
565 			dev_err(dev, "%s record count == 0 (%zu / %zu)\n",
566 				name, mem_sz, record_size);
567 			goto fail;
568 		}
569 	}
570 
571 	if (*paddr + mem_sz - cxt->phys_addr > cxt->size) {
572 		dev_err(dev, "no room for %s mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
573 			name,
574 			mem_sz, (unsigned long long)*paddr,
575 			cxt->size, (unsigned long long)cxt->phys_addr);
576 		goto fail;
577 	}
578 
579 	zone_sz = mem_sz / *cnt;
580 	if (!zone_sz) {
581 		dev_err(dev, "%s zone size == 0\n", name);
582 		goto fail;
583 	}
584 
585 	prz_ar = kcalloc(*cnt, sizeof(**przs), GFP_KERNEL);
586 	if (!prz_ar)
587 		goto fail;
588 
589 	for (i = 0; i < *cnt; i++) {
590 		prz_ar[i] = persistent_ram_new(*paddr, zone_sz, sig,
591 						  &cxt->ecc_info,
592 						  cxt->memtype, flags);
593 		if (IS_ERR(prz_ar[i])) {
594 			err = PTR_ERR(prz_ar[i]);
595 			dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
596 				name, record_size,
597 				(unsigned long long)*paddr, err);
598 
599 			while (i > 0) {
600 				i--;
601 				persistent_ram_free(prz_ar[i]);
602 			}
603 			kfree(prz_ar);
604 			goto fail;
605 		}
606 		*paddr += zone_sz;
607 	}
608 
609 	*przs = prz_ar;
610 	return 0;
611 
612 fail:
613 	*cnt = 0;
614 	return err;
615 }
616 
617 static int ramoops_init_prz(const char *name,
618 			    struct device *dev, struct ramoops_context *cxt,
619 			    struct persistent_ram_zone **prz,
620 			    phys_addr_t *paddr, size_t sz, u32 sig)
621 {
622 	if (!sz)
623 		return 0;
624 
625 	if (*paddr + sz - cxt->phys_addr > cxt->size) {
626 		dev_err(dev, "no room for %s mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
627 			name, sz, (unsigned long long)*paddr,
628 			cxt->size, (unsigned long long)cxt->phys_addr);
629 		return -ENOMEM;
630 	}
631 
632 	*prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info,
633 				  cxt->memtype, 0);
634 	if (IS_ERR(*prz)) {
635 		int err = PTR_ERR(*prz);
636 
637 		dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
638 			name, sz, (unsigned long long)*paddr, err);
639 		return err;
640 	}
641 
642 	persistent_ram_zap(*prz);
643 
644 	*paddr += sz;
645 
646 	return 0;
647 }
648 
649 static int ramoops_parse_dt_size(struct platform_device *pdev,
650 				 const char *propname, u32 *value)
651 {
652 	u32 val32 = 0;
653 	int ret;
654 
655 	ret = of_property_read_u32(pdev->dev.of_node, propname, &val32);
656 	if (ret < 0 && ret != -EINVAL) {
657 		dev_err(&pdev->dev, "failed to parse property %s: %d\n",
658 			propname, ret);
659 		return ret;
660 	}
661 
662 	if (val32 > INT_MAX) {
663 		dev_err(&pdev->dev, "%s %u > INT_MAX\n", propname, val32);
664 		return -EOVERFLOW;
665 	}
666 
667 	*value = val32;
668 	return 0;
669 }
670 
671 static int ramoops_parse_dt(struct platform_device *pdev,
672 			    struct ramoops_platform_data *pdata)
673 {
674 	struct device_node *of_node = pdev->dev.of_node;
675 	struct resource *res;
676 	u32 value;
677 	int ret;
678 
679 	dev_dbg(&pdev->dev, "using Device Tree\n");
680 
681 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
682 	if (!res) {
683 		dev_err(&pdev->dev,
684 			"failed to locate DT /reserved-memory resource\n");
685 		return -EINVAL;
686 	}
687 
688 	pdata->mem_size = resource_size(res);
689 	pdata->mem_address = res->start;
690 	pdata->mem_type = of_property_read_bool(of_node, "unbuffered");
691 	pdata->dump_oops = !of_property_read_bool(of_node, "no-dump-oops");
692 
693 #define parse_size(name, field) {					\
694 		ret = ramoops_parse_dt_size(pdev, name, &value);	\
695 		if (ret < 0)						\
696 			return ret;					\
697 		field = value;						\
698 	}
699 
700 	parse_size("record-size", pdata->record_size);
701 	parse_size("console-size", pdata->console_size);
702 	parse_size("ftrace-size", pdata->ftrace_size);
703 	parse_size("pmsg-size", pdata->pmsg_size);
704 	parse_size("ecc-size", pdata->ecc_info.ecc_size);
705 	parse_size("flags", pdata->flags);
706 
707 #undef parse_size
708 
709 	return 0;
710 }
711 
712 static int ramoops_probe(struct platform_device *pdev)
713 {
714 	struct device *dev = &pdev->dev;
715 	struct ramoops_platform_data *pdata = dev->platform_data;
716 	struct ramoops_context *cxt = &oops_cxt;
717 	size_t dump_mem_sz;
718 	phys_addr_t paddr;
719 	int err = -EINVAL;
720 
721 	if (dev_of_node(dev) && !pdata) {
722 		pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
723 		if (!pdata) {
724 			pr_err("cannot allocate platform data buffer\n");
725 			err = -ENOMEM;
726 			goto fail_out;
727 		}
728 
729 		err = ramoops_parse_dt(pdev, pdata);
730 		if (err < 0)
731 			goto fail_out;
732 	}
733 
734 	/*
735 	 * Only a single ramoops area allowed at a time, so fail extra
736 	 * probes.
737 	 */
738 	if (cxt->max_dump_cnt) {
739 		pr_err("already initialized\n");
740 		goto fail_out;
741 	}
742 
743 	/* Make sure we didn't get bogus platform data pointer. */
744 	if (!pdata) {
745 		pr_err("NULL platform data\n");
746 		goto fail_out;
747 	}
748 
749 	if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size &&
750 			!pdata->ftrace_size && !pdata->pmsg_size)) {
751 		pr_err("The memory size and the record/console size must be "
752 			"non-zero\n");
753 		goto fail_out;
754 	}
755 
756 	if (pdata->record_size && !is_power_of_2(pdata->record_size))
757 		pdata->record_size = rounddown_pow_of_two(pdata->record_size);
758 	if (pdata->console_size && !is_power_of_2(pdata->console_size))
759 		pdata->console_size = rounddown_pow_of_two(pdata->console_size);
760 	if (pdata->ftrace_size && !is_power_of_2(pdata->ftrace_size))
761 		pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
762 	if (pdata->pmsg_size && !is_power_of_2(pdata->pmsg_size))
763 		pdata->pmsg_size = rounddown_pow_of_two(pdata->pmsg_size);
764 
765 	cxt->size = pdata->mem_size;
766 	cxt->phys_addr = pdata->mem_address;
767 	cxt->memtype = pdata->mem_type;
768 	cxt->record_size = pdata->record_size;
769 	cxt->console_size = pdata->console_size;
770 	cxt->ftrace_size = pdata->ftrace_size;
771 	cxt->pmsg_size = pdata->pmsg_size;
772 	cxt->dump_oops = pdata->dump_oops;
773 	cxt->flags = pdata->flags;
774 	cxt->ecc_info = pdata->ecc_info;
775 
776 	paddr = cxt->phys_addr;
777 
778 	dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size
779 			- cxt->pmsg_size;
780 	err = ramoops_init_przs("dump", dev, cxt, &cxt->dprzs, &paddr,
781 				dump_mem_sz, cxt->record_size,
782 				&cxt->max_dump_cnt, 0, 0);
783 	if (err)
784 		goto fail_out;
785 
786 	err = ramoops_init_prz("console", dev, cxt, &cxt->cprz, &paddr,
787 			       cxt->console_size, 0);
788 	if (err)
789 		goto fail_init_cprz;
790 
791 	cxt->max_ftrace_cnt = (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
792 				? nr_cpu_ids
793 				: 1;
794 	err = ramoops_init_przs("ftrace", dev, cxt, &cxt->fprzs, &paddr,
795 				cxt->ftrace_size, -1,
796 				&cxt->max_ftrace_cnt, LINUX_VERSION_CODE,
797 				(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
798 					? PRZ_FLAG_NO_LOCK : 0);
799 	if (err)
800 		goto fail_init_fprz;
801 
802 	err = ramoops_init_prz("pmsg", dev, cxt, &cxt->mprz, &paddr,
803 				cxt->pmsg_size, 0);
804 	if (err)
805 		goto fail_init_mprz;
806 
807 	cxt->pstore.data = cxt;
808 	/*
809 	 * Console can handle any buffer size, so prefer LOG_LINE_MAX. If we
810 	 * have to handle dumps, we must have at least record_size buffer. And
811 	 * for ftrace, bufsize is irrelevant (if bufsize is 0, buf will be
812 	 * ZERO_SIZE_PTR).
813 	 */
814 	if (cxt->console_size)
815 		cxt->pstore.bufsize = 1024; /* LOG_LINE_MAX */
816 	cxt->pstore.bufsize = max(cxt->record_size, cxt->pstore.bufsize);
817 	cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
818 	if (!cxt->pstore.buf) {
819 		pr_err("cannot allocate pstore buffer\n");
820 		err = -ENOMEM;
821 		goto fail_clear;
822 	}
823 	spin_lock_init(&cxt->pstore.buf_lock);
824 
825 	cxt->pstore.flags = PSTORE_FLAGS_DMESG;
826 	if (cxt->console_size)
827 		cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE;
828 	if (cxt->ftrace_size)
829 		cxt->pstore.flags |= PSTORE_FLAGS_FTRACE;
830 	if (cxt->pmsg_size)
831 		cxt->pstore.flags |= PSTORE_FLAGS_PMSG;
832 
833 	err = pstore_register(&cxt->pstore);
834 	if (err) {
835 		pr_err("registering with pstore failed\n");
836 		goto fail_buf;
837 	}
838 
839 	/*
840 	 * Update the module parameter variables as well so they are visible
841 	 * through /sys/module/ramoops/parameters/
842 	 */
843 	mem_size = pdata->mem_size;
844 	mem_address = pdata->mem_address;
845 	record_size = pdata->record_size;
846 	dump_oops = pdata->dump_oops;
847 	ramoops_console_size = pdata->console_size;
848 	ramoops_pmsg_size = pdata->pmsg_size;
849 	ramoops_ftrace_size = pdata->ftrace_size;
850 
851 	pr_info("attached 0x%lx@0x%llx, ecc: %d/%d\n",
852 		cxt->size, (unsigned long long)cxt->phys_addr,
853 		cxt->ecc_info.ecc_size, cxt->ecc_info.block_size);
854 
855 	return 0;
856 
857 fail_buf:
858 	kfree(cxt->pstore.buf);
859 fail_clear:
860 	cxt->pstore.bufsize = 0;
861 	persistent_ram_free(cxt->mprz);
862 fail_init_mprz:
863 fail_init_fprz:
864 	persistent_ram_free(cxt->cprz);
865 fail_init_cprz:
866 	ramoops_free_przs(cxt);
867 fail_out:
868 	return err;
869 }
870 
871 static int ramoops_remove(struct platform_device *pdev)
872 {
873 	struct ramoops_context *cxt = &oops_cxt;
874 
875 	pstore_unregister(&cxt->pstore);
876 
877 	kfree(cxt->pstore.buf);
878 	cxt->pstore.bufsize = 0;
879 
880 	persistent_ram_free(cxt->mprz);
881 	persistent_ram_free(cxt->cprz);
882 	ramoops_free_przs(cxt);
883 
884 	return 0;
885 }
886 
887 static const struct of_device_id dt_match[] = {
888 	{ .compatible = "ramoops" },
889 	{}
890 };
891 
892 static struct platform_driver ramoops_driver = {
893 	.probe		= ramoops_probe,
894 	.remove		= ramoops_remove,
895 	.driver		= {
896 		.name		= "ramoops",
897 		.of_match_table	= dt_match,
898 	},
899 };
900 
901 static void ramoops_register_dummy(void)
902 {
903 	if (!mem_size)
904 		return;
905 
906 	pr_info("using module parameters\n");
907 
908 	dummy_data = kzalloc(sizeof(*dummy_data), GFP_KERNEL);
909 	if (!dummy_data) {
910 		pr_info("could not allocate pdata\n");
911 		return;
912 	}
913 
914 	dummy_data->mem_size = mem_size;
915 	dummy_data->mem_address = mem_address;
916 	dummy_data->mem_type = mem_type;
917 	dummy_data->record_size = record_size;
918 	dummy_data->console_size = ramoops_console_size;
919 	dummy_data->ftrace_size = ramoops_ftrace_size;
920 	dummy_data->pmsg_size = ramoops_pmsg_size;
921 	dummy_data->dump_oops = dump_oops;
922 	dummy_data->flags = RAMOOPS_FLAG_FTRACE_PER_CPU;
923 
924 	/*
925 	 * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
926 	 * (using 1 byte for ECC isn't much of use anyway).
927 	 */
928 	dummy_data->ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
929 
930 	dummy = platform_device_register_data(NULL, "ramoops", -1,
931 			dummy_data, sizeof(struct ramoops_platform_data));
932 	if (IS_ERR(dummy)) {
933 		pr_info("could not create platform device: %ld\n",
934 			PTR_ERR(dummy));
935 	}
936 }
937 
938 static int __init ramoops_init(void)
939 {
940 	ramoops_register_dummy();
941 	return platform_driver_register(&ramoops_driver);
942 }
943 late_initcall(ramoops_init);
944 
945 static void __exit ramoops_exit(void)
946 {
947 	platform_driver_unregister(&ramoops_driver);
948 	platform_device_unregister(dummy);
949 	kfree(dummy_data);
950 }
951 module_exit(ramoops_exit);
952 
953 MODULE_LICENSE("GPL");
954 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
955 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");
956