xref: /openbmc/linux/fs/pstore/ram.c (revision 4cff79e9)
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 timespec *time,
157 				  bool *compressed)
158 {
159 	char data_type;
160 	int header_length = 0;
161 
162 	if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lu.%lu-%c\n%n", &time->tv_sec,
163 			&time->tv_nsec, &data_type, &header_length) == 3) {
164 		if (data_type == 'C')
165 			*compressed = true;
166 		else
167 			*compressed = false;
168 	} else if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lu.%lu\n%n",
169 			&time->tv_sec, &time->tv_nsec, &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 					   cxt->max_dump_cnt, &record->id,
258 					   &record->type,
259 					   PSTORE_TYPE_DMESG, 1);
260 		if (!prz_ok(prz))
261 			continue;
262 		header_length = ramoops_read_kmsg_hdr(persistent_ram_old(prz),
263 						      &record->time,
264 						      &record->compressed);
265 		/* Clear and skip this DMESG record if it has no valid header */
266 		if (!header_length) {
267 			persistent_ram_free_old(prz);
268 			persistent_ram_zap(prz);
269 			prz = NULL;
270 		}
271 	}
272 
273 	if (!prz_ok(prz))
274 		prz = ramoops_get_next_prz(&cxt->cprz, &cxt->console_read_cnt,
275 					   1, &record->id, &record->type,
276 					   PSTORE_TYPE_CONSOLE, 0);
277 
278 	if (!prz_ok(prz))
279 		prz = ramoops_get_next_prz(&cxt->mprz, &cxt->pmsg_read_cnt,
280 					   1, &record->id, &record->type,
281 					   PSTORE_TYPE_PMSG, 0);
282 
283 	/* ftrace is last since it may want to dynamically allocate memory. */
284 	if (!prz_ok(prz)) {
285 		if (!(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)) {
286 			prz = ramoops_get_next_prz(cxt->fprzs,
287 					&cxt->ftrace_read_cnt, 1, &record->id,
288 					&record->type, PSTORE_TYPE_FTRACE, 0);
289 		} else {
290 			/*
291 			 * Build a new dummy record which combines all the
292 			 * per-cpu records including metadata and ecc info.
293 			 */
294 			struct persistent_ram_zone *tmp_prz, *prz_next;
295 
296 			tmp_prz = kzalloc(sizeof(struct persistent_ram_zone),
297 					  GFP_KERNEL);
298 			if (!tmp_prz)
299 				return -ENOMEM;
300 			free_prz = true;
301 
302 			while (cxt->ftrace_read_cnt < cxt->max_ftrace_cnt) {
303 				prz_next = ramoops_get_next_prz(cxt->fprzs,
304 						&cxt->ftrace_read_cnt,
305 						cxt->max_ftrace_cnt,
306 						&record->id,
307 						&record->type,
308 						PSTORE_TYPE_FTRACE, 0);
309 
310 				if (!prz_ok(prz_next))
311 					continue;
312 
313 				tmp_prz->ecc_info = prz_next->ecc_info;
314 				tmp_prz->corrected_bytes +=
315 						prz_next->corrected_bytes;
316 				tmp_prz->bad_blocks += prz_next->bad_blocks;
317 				size = ftrace_log_combine(tmp_prz, prz_next);
318 				if (size)
319 					goto out;
320 			}
321 			record->id = 0;
322 			prz = tmp_prz;
323 		}
324 	}
325 
326 	if (!prz_ok(prz)) {
327 		size = 0;
328 		goto out;
329 	}
330 
331 	size = persistent_ram_old_size(prz) - header_length;
332 
333 	/* ECC correction notice */
334 	record->ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
335 
336 	record->buf = kmalloc(size + record->ecc_notice_size + 1, GFP_KERNEL);
337 	if (record->buf == NULL) {
338 		size = -ENOMEM;
339 		goto out;
340 	}
341 
342 	memcpy(record->buf, (char *)persistent_ram_old(prz) + header_length,
343 	       size);
344 
345 	persistent_ram_ecc_string(prz, record->buf + size,
346 				  record->ecc_notice_size + 1);
347 
348 out:
349 	if (free_prz) {
350 		kfree(prz->old_log);
351 		kfree(prz);
352 	}
353 
354 	return size;
355 }
356 
357 static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz,
358 				     struct pstore_record *record)
359 {
360 	char *hdr;
361 	size_t len;
362 
363 	hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu-%c\n",
364 		record->time.tv_sec,
365 		record->time.tv_nsec / 1000,
366 		record->compressed ? 'C' : 'D');
367 	WARN_ON_ONCE(!hdr);
368 	len = hdr ? strlen(hdr) : 0;
369 	persistent_ram_write(prz, hdr, len);
370 	kfree(hdr);
371 
372 	return len;
373 }
374 
375 static int notrace ramoops_pstore_write(struct pstore_record *record)
376 {
377 	struct ramoops_context *cxt = record->psi->data;
378 	struct persistent_ram_zone *prz;
379 	size_t size, hlen;
380 
381 	if (record->type == PSTORE_TYPE_CONSOLE) {
382 		if (!cxt->cprz)
383 			return -ENOMEM;
384 		persistent_ram_write(cxt->cprz, record->buf, record->size);
385 		return 0;
386 	} else if (record->type == PSTORE_TYPE_FTRACE) {
387 		int zonenum;
388 
389 		if (!cxt->fprzs)
390 			return -ENOMEM;
391 		/*
392 		 * Choose zone by if we're using per-cpu buffers.
393 		 */
394 		if (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
395 			zonenum = smp_processor_id();
396 		else
397 			zonenum = 0;
398 
399 		persistent_ram_write(cxt->fprzs[zonenum], record->buf,
400 				     record->size);
401 		return 0;
402 	} else if (record->type == PSTORE_TYPE_PMSG) {
403 		pr_warn_ratelimited("PMSG shouldn't call %s\n", __func__);
404 		return -EINVAL;
405 	}
406 
407 	if (record->type != PSTORE_TYPE_DMESG)
408 		return -EINVAL;
409 
410 	/*
411 	 * Out of the various dmesg dump types, ramoops is currently designed
412 	 * to only store crash logs, rather than storing general kernel logs.
413 	 */
414 	if (record->reason != KMSG_DUMP_OOPS &&
415 	    record->reason != KMSG_DUMP_PANIC)
416 		return -EINVAL;
417 
418 	/* Skip Oopes when configured to do so. */
419 	if (record->reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
420 		return -EINVAL;
421 
422 	/*
423 	 * Explicitly only take the first part of any new crash.
424 	 * If our buffer is larger than kmsg_bytes, this can never happen,
425 	 * and if our buffer is smaller than kmsg_bytes, we don't want the
426 	 * report split across multiple records.
427 	 */
428 	if (record->part != 1)
429 		return -ENOSPC;
430 
431 	if (!cxt->dprzs)
432 		return -ENOSPC;
433 
434 	prz = cxt->dprzs[cxt->dump_write_cnt];
435 
436 	/* Build header and append record contents. */
437 	hlen = ramoops_write_kmsg_hdr(prz, record);
438 	size = record->size;
439 	if (size + hlen > prz->buffer_size)
440 		size = prz->buffer_size - hlen;
441 	persistent_ram_write(prz, record->buf, size);
442 
443 	cxt->dump_write_cnt = (cxt->dump_write_cnt + 1) % cxt->max_dump_cnt;
444 
445 	return 0;
446 }
447 
448 static int notrace ramoops_pstore_write_user(struct pstore_record *record,
449 					     const char __user *buf)
450 {
451 	if (record->type == PSTORE_TYPE_PMSG) {
452 		struct ramoops_context *cxt = record->psi->data;
453 
454 		if (!cxt->mprz)
455 			return -ENOMEM;
456 		return persistent_ram_write_user(cxt->mprz, buf, record->size);
457 	}
458 
459 	return -EINVAL;
460 }
461 
462 static int ramoops_pstore_erase(struct pstore_record *record)
463 {
464 	struct ramoops_context *cxt = record->psi->data;
465 	struct persistent_ram_zone *prz;
466 
467 	switch (record->type) {
468 	case PSTORE_TYPE_DMESG:
469 		if (record->id >= cxt->max_dump_cnt)
470 			return -EINVAL;
471 		prz = cxt->dprzs[record->id];
472 		break;
473 	case PSTORE_TYPE_CONSOLE:
474 		prz = cxt->cprz;
475 		break;
476 	case PSTORE_TYPE_FTRACE:
477 		if (record->id >= cxt->max_ftrace_cnt)
478 			return -EINVAL;
479 		prz = cxt->fprzs[record->id];
480 		break;
481 	case PSTORE_TYPE_PMSG:
482 		prz = cxt->mprz;
483 		break;
484 	default:
485 		return -EINVAL;
486 	}
487 
488 	persistent_ram_free_old(prz);
489 	persistent_ram_zap(prz);
490 
491 	return 0;
492 }
493 
494 static struct ramoops_context oops_cxt = {
495 	.pstore = {
496 		.owner	= THIS_MODULE,
497 		.name	= "ramoops",
498 		.open	= ramoops_pstore_open,
499 		.read	= ramoops_pstore_read,
500 		.write	= ramoops_pstore_write,
501 		.write_user	= ramoops_pstore_write_user,
502 		.erase	= ramoops_pstore_erase,
503 	},
504 };
505 
506 static void ramoops_free_przs(struct ramoops_context *cxt)
507 {
508 	int i;
509 
510 	/* Free dump PRZs */
511 	if (cxt->dprzs) {
512 		for (i = 0; i < cxt->max_dump_cnt; i++)
513 			persistent_ram_free(cxt->dprzs[i]);
514 
515 		kfree(cxt->dprzs);
516 		cxt->max_dump_cnt = 0;
517 	}
518 
519 	/* Free ftrace PRZs */
520 	if (cxt->fprzs) {
521 		for (i = 0; i < cxt->max_ftrace_cnt; i++)
522 			persistent_ram_free(cxt->fprzs[i]);
523 		kfree(cxt->fprzs);
524 		cxt->max_ftrace_cnt = 0;
525 	}
526 }
527 
528 static int ramoops_init_przs(const char *name,
529 			     struct device *dev, struct ramoops_context *cxt,
530 			     struct persistent_ram_zone ***przs,
531 			     phys_addr_t *paddr, size_t mem_sz,
532 			     ssize_t record_size,
533 			     unsigned int *cnt, u32 sig, u32 flags)
534 {
535 	int err = -ENOMEM;
536 	int i;
537 	size_t zone_sz;
538 	struct persistent_ram_zone **prz_ar;
539 
540 	/* Allocate nothing for 0 mem_sz or 0 record_size. */
541 	if (mem_sz == 0 || record_size == 0) {
542 		*cnt = 0;
543 		return 0;
544 	}
545 
546 	/*
547 	 * If we have a negative record size, calculate it based on
548 	 * mem_sz / *cnt. If we have a positive record size, calculate
549 	 * cnt from mem_sz / record_size.
550 	 */
551 	if (record_size < 0) {
552 		if (*cnt == 0)
553 			return 0;
554 		record_size = mem_sz / *cnt;
555 		if (record_size == 0) {
556 			dev_err(dev, "%s record size == 0 (%zu / %u)\n",
557 				name, mem_sz, *cnt);
558 			goto fail;
559 		}
560 	} else {
561 		*cnt = mem_sz / record_size;
562 		if (*cnt == 0) {
563 			dev_err(dev, "%s record count == 0 (%zu / %zu)\n",
564 				name, mem_sz, record_size);
565 			goto fail;
566 		}
567 	}
568 
569 	if (*paddr + mem_sz - cxt->phys_addr > cxt->size) {
570 		dev_err(dev, "no room for %s mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
571 			name,
572 			mem_sz, (unsigned long long)*paddr,
573 			cxt->size, (unsigned long long)cxt->phys_addr);
574 		goto fail;
575 	}
576 
577 	zone_sz = mem_sz / *cnt;
578 	if (!zone_sz) {
579 		dev_err(dev, "%s zone size == 0\n", name);
580 		goto fail;
581 	}
582 
583 	prz_ar = kcalloc(*cnt, sizeof(**przs), GFP_KERNEL);
584 	if (!prz_ar)
585 		goto fail;
586 
587 	for (i = 0; i < *cnt; i++) {
588 		prz_ar[i] = persistent_ram_new(*paddr, zone_sz, sig,
589 						  &cxt->ecc_info,
590 						  cxt->memtype, flags);
591 		if (IS_ERR(prz_ar[i])) {
592 			err = PTR_ERR(prz_ar[i]);
593 			dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
594 				name, record_size,
595 				(unsigned long long)*paddr, err);
596 
597 			while (i > 0) {
598 				i--;
599 				persistent_ram_free(prz_ar[i]);
600 			}
601 			kfree(prz_ar);
602 			goto fail;
603 		}
604 		*paddr += zone_sz;
605 	}
606 
607 	*przs = prz_ar;
608 	return 0;
609 
610 fail:
611 	*cnt = 0;
612 	return err;
613 }
614 
615 static int ramoops_init_prz(const char *name,
616 			    struct device *dev, struct ramoops_context *cxt,
617 			    struct persistent_ram_zone **prz,
618 			    phys_addr_t *paddr, size_t sz, u32 sig)
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 	*prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info,
631 				  cxt->memtype, 0);
632 	if (IS_ERR(*prz)) {
633 		int err = PTR_ERR(*prz);
634 
635 		dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
636 			name, sz, (unsigned long long)*paddr, err);
637 		return err;
638 	}
639 
640 	persistent_ram_zap(*prz);
641 
642 	*paddr += sz;
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("dump", 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 	 * Console can handle any buffer size, so prefer LOG_LINE_MAX. If we
808 	 * have to handle dumps, we must have at least record_size buffer. And
809 	 * for ftrace, bufsize is irrelevant (if bufsize is 0, buf will be
810 	 * ZERO_SIZE_PTR).
811 	 */
812 	if (cxt->console_size)
813 		cxt->pstore.bufsize = 1024; /* LOG_LINE_MAX */
814 	cxt->pstore.bufsize = max(cxt->record_size, cxt->pstore.bufsize);
815 	cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
816 	if (!cxt->pstore.buf) {
817 		pr_err("cannot allocate pstore buffer\n");
818 		err = -ENOMEM;
819 		goto fail_clear;
820 	}
821 	spin_lock_init(&cxt->pstore.buf_lock);
822 
823 	cxt->pstore.flags = PSTORE_FLAGS_DMESG;
824 	if (cxt->console_size)
825 		cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE;
826 	if (cxt->ftrace_size)
827 		cxt->pstore.flags |= PSTORE_FLAGS_FTRACE;
828 	if (cxt->pmsg_size)
829 		cxt->pstore.flags |= PSTORE_FLAGS_PMSG;
830 
831 	err = pstore_register(&cxt->pstore);
832 	if (err) {
833 		pr_err("registering with pstore failed\n");
834 		goto fail_buf;
835 	}
836 
837 	/*
838 	 * Update the module parameter variables as well so they are visible
839 	 * through /sys/module/ramoops/parameters/
840 	 */
841 	mem_size = pdata->mem_size;
842 	mem_address = pdata->mem_address;
843 	record_size = pdata->record_size;
844 	dump_oops = pdata->dump_oops;
845 	ramoops_console_size = pdata->console_size;
846 	ramoops_pmsg_size = pdata->pmsg_size;
847 	ramoops_ftrace_size = pdata->ftrace_size;
848 
849 	pr_info("attached 0x%lx@0x%llx, ecc: %d/%d\n",
850 		cxt->size, (unsigned long long)cxt->phys_addr,
851 		cxt->ecc_info.ecc_size, cxt->ecc_info.block_size);
852 
853 	return 0;
854 
855 fail_buf:
856 	kfree(cxt->pstore.buf);
857 fail_clear:
858 	cxt->pstore.bufsize = 0;
859 	persistent_ram_free(cxt->mprz);
860 fail_init_mprz:
861 fail_init_fprz:
862 	persistent_ram_free(cxt->cprz);
863 fail_init_cprz:
864 	ramoops_free_przs(cxt);
865 fail_out:
866 	return err;
867 }
868 
869 static int ramoops_remove(struct platform_device *pdev)
870 {
871 	struct ramoops_context *cxt = &oops_cxt;
872 
873 	pstore_unregister(&cxt->pstore);
874 
875 	kfree(cxt->pstore.buf);
876 	cxt->pstore.bufsize = 0;
877 
878 	persistent_ram_free(cxt->mprz);
879 	persistent_ram_free(cxt->cprz);
880 	ramoops_free_przs(cxt);
881 
882 	return 0;
883 }
884 
885 static const struct of_device_id dt_match[] = {
886 	{ .compatible = "ramoops" },
887 	{}
888 };
889 
890 static struct platform_driver ramoops_driver = {
891 	.probe		= ramoops_probe,
892 	.remove		= ramoops_remove,
893 	.driver		= {
894 		.name		= "ramoops",
895 		.of_match_table	= dt_match,
896 	},
897 };
898 
899 static void ramoops_register_dummy(void)
900 {
901 	if (!mem_size)
902 		return;
903 
904 	pr_info("using module parameters\n");
905 
906 	dummy_data = kzalloc(sizeof(*dummy_data), GFP_KERNEL);
907 	if (!dummy_data) {
908 		pr_info("could not allocate pdata\n");
909 		return;
910 	}
911 
912 	dummy_data->mem_size = mem_size;
913 	dummy_data->mem_address = mem_address;
914 	dummy_data->mem_type = mem_type;
915 	dummy_data->record_size = record_size;
916 	dummy_data->console_size = ramoops_console_size;
917 	dummy_data->ftrace_size = ramoops_ftrace_size;
918 	dummy_data->pmsg_size = ramoops_pmsg_size;
919 	dummy_data->dump_oops = dump_oops;
920 	dummy_data->flags = RAMOOPS_FLAG_FTRACE_PER_CPU;
921 
922 	/*
923 	 * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
924 	 * (using 1 byte for ECC isn't much of use anyway).
925 	 */
926 	dummy_data->ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
927 
928 	dummy = platform_device_register_data(NULL, "ramoops", -1,
929 			dummy_data, sizeof(struct ramoops_platform_data));
930 	if (IS_ERR(dummy)) {
931 		pr_info("could not create platform device: %ld\n",
932 			PTR_ERR(dummy));
933 	}
934 }
935 
936 static int __init ramoops_init(void)
937 {
938 	ramoops_register_dummy();
939 	return platform_driver_register(&ramoops_driver);
940 }
941 late_initcall(ramoops_init);
942 
943 static void __exit ramoops_exit(void)
944 {
945 	platform_driver_unregister(&ramoops_driver);
946 	platform_device_unregister(dummy);
947 	kfree(dummy_data);
948 }
949 module_exit(ramoops_exit);
950 
951 MODULE_LICENSE("GPL");
952 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
953 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");
954