xref: /openbmc/linux/fs/pstore/ram.c (revision 4beec1d7)
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/time.h>
31 #include <linux/io.h>
32 #include <linux/ioport.h>
33 #include <linux/platform_device.h>
34 #include <linux/slab.h>
35 #include <linux/compiler.h>
36 #include <linux/pstore_ram.h>
37 #include <linux/of.h>
38 #include <linux/of_address.h>
39 
40 #define RAMOOPS_KERNMSG_HDR "===="
41 #define MIN_MEM_SIZE 4096UL
42 
43 static ulong record_size = MIN_MEM_SIZE;
44 module_param(record_size, ulong, 0400);
45 MODULE_PARM_DESC(record_size,
46 		"size of each dump done on oops/panic");
47 
48 static ulong ramoops_console_size = MIN_MEM_SIZE;
49 module_param_named(console_size, ramoops_console_size, ulong, 0400);
50 MODULE_PARM_DESC(console_size, "size of kernel console log");
51 
52 static ulong ramoops_ftrace_size = MIN_MEM_SIZE;
53 module_param_named(ftrace_size, ramoops_ftrace_size, ulong, 0400);
54 MODULE_PARM_DESC(ftrace_size, "size of ftrace log");
55 
56 static ulong ramoops_pmsg_size = MIN_MEM_SIZE;
57 module_param_named(pmsg_size, ramoops_pmsg_size, ulong, 0400);
58 MODULE_PARM_DESC(pmsg_size, "size of user space message log");
59 
60 static unsigned long long mem_address;
61 module_param(mem_address, ullong, 0400);
62 MODULE_PARM_DESC(mem_address,
63 		"start of reserved RAM used to store oops/panic logs");
64 
65 static ulong mem_size;
66 module_param(mem_size, ulong, 0400);
67 MODULE_PARM_DESC(mem_size,
68 		"size of reserved RAM used to store oops/panic logs");
69 
70 static unsigned int mem_type;
71 module_param(mem_type, uint, 0600);
72 MODULE_PARM_DESC(mem_type,
73 		"set to 1 to try to use unbuffered memory (default 0)");
74 
75 static int dump_oops = 1;
76 module_param(dump_oops, int, 0600);
77 MODULE_PARM_DESC(dump_oops,
78 		"set to 1 to dump oopses, 0 to only dump panics (default 1)");
79 
80 static int ramoops_ecc;
81 module_param_named(ecc, ramoops_ecc, int, 0600);
82 MODULE_PARM_DESC(ramoops_ecc,
83 		"if non-zero, the option enables ECC support and specifies "
84 		"ECC buffer size in bytes (1 is a special value, means 16 "
85 		"bytes ECC)");
86 
87 struct ramoops_context {
88 	struct persistent_ram_zone **dprzs;	/* Oops dump zones */
89 	struct persistent_ram_zone *cprz;	/* Console zone */
90 	struct persistent_ram_zone **fprzs;	/* Ftrace zones */
91 	struct persistent_ram_zone *mprz;	/* PMSG zone */
92 	phys_addr_t phys_addr;
93 	unsigned long size;
94 	unsigned int memtype;
95 	size_t record_size;
96 	size_t console_size;
97 	size_t ftrace_size;
98 	size_t pmsg_size;
99 	int dump_oops;
100 	u32 flags;
101 	struct persistent_ram_ecc_info ecc_info;
102 	unsigned int max_dump_cnt;
103 	unsigned int dump_write_cnt;
104 	/* _read_cnt need clear on ramoops_pstore_open */
105 	unsigned int dump_read_cnt;
106 	unsigned int console_read_cnt;
107 	unsigned int max_ftrace_cnt;
108 	unsigned int ftrace_read_cnt;
109 	unsigned int pmsg_read_cnt;
110 	struct pstore_info pstore;
111 };
112 
113 static struct platform_device *dummy;
114 static struct ramoops_platform_data *dummy_data;
115 
116 static int ramoops_pstore_open(struct pstore_info *psi)
117 {
118 	struct ramoops_context *cxt = psi->data;
119 
120 	cxt->dump_read_cnt = 0;
121 	cxt->console_read_cnt = 0;
122 	cxt->ftrace_read_cnt = 0;
123 	cxt->pmsg_read_cnt = 0;
124 	return 0;
125 }
126 
127 static struct persistent_ram_zone *
128 ramoops_get_next_prz(struct persistent_ram_zone *przs[], uint *c, uint max,
129 		     u64 *id,
130 		     enum pstore_type_id *typep, enum pstore_type_id type,
131 		     bool update)
132 {
133 	struct persistent_ram_zone *prz;
134 	int i = (*c)++;
135 
136 	if (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(u64 *id, enum pstore_type_id *type,
238 				   int *count, struct timespec *time,
239 				   char **buf, bool *compressed,
240 				   ssize_t *ecc_notice_size,
241 				   struct pstore_info *psi)
242 {
243 	ssize_t size = 0;
244 	struct ramoops_context *cxt = psi->data;
245 	struct persistent_ram_zone *prz = NULL;
246 	int header_length = 0;
247 	bool free_prz = false;
248 
249 	/* Ramoops headers provide time stamps for PSTORE_TYPE_DMESG, but
250 	 * PSTORE_TYPE_CONSOLE and PSTORE_TYPE_FTRACE don't currently have
251 	 * valid time stamps, so it is initialized to zero.
252 	 */
253 	time->tv_sec = 0;
254 	time->tv_nsec = 0;
255 	*compressed = false;
256 
257 	/* Find the next valid persistent_ram_zone for DMESG */
258 	while (cxt->dump_read_cnt < cxt->max_dump_cnt && !prz) {
259 		prz = ramoops_get_next_prz(cxt->dprzs, &cxt->dump_read_cnt,
260 					   cxt->max_dump_cnt, id, 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 						      time, compressed);
266 		/* Clear and skip this DMESG record if it has no valid header */
267 		if (!header_length) {
268 			persistent_ram_free_old(prz);
269 			persistent_ram_zap(prz);
270 			prz = NULL;
271 		}
272 	}
273 
274 	if (!prz_ok(prz))
275 		prz = ramoops_get_next_prz(&cxt->cprz, &cxt->console_read_cnt,
276 					   1, id, type, PSTORE_TYPE_CONSOLE, 0);
277 
278 	if (!prz_ok(prz))
279 		prz = ramoops_get_next_prz(&cxt->mprz, &cxt->pmsg_read_cnt,
280 					   1, id, type, PSTORE_TYPE_PMSG, 0);
281 
282 	/* ftrace is last since it may want to dynamically allocate memory. */
283 	if (!prz_ok(prz) && cxt->fprzs) {
284 		if (!(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)) {
285 			prz = ramoops_get_next_prz(cxt->fprzs,
286 					&cxt->ftrace_read_cnt, 1, id, type,
287 					PSTORE_TYPE_FTRACE, 0);
288 		} else {
289 			/*
290 			 * Build a new dummy record which combines all the
291 			 * per-cpu records including metadata and ecc info.
292 			 */
293 			struct persistent_ram_zone *tmp_prz, *prz_next;
294 
295 			tmp_prz = kzalloc(sizeof(struct persistent_ram_zone),
296 					  GFP_KERNEL);
297 			if (!tmp_prz)
298 				return -ENOMEM;
299 			free_prz = true;
300 
301 			while (cxt->ftrace_read_cnt < cxt->max_ftrace_cnt) {
302 				prz_next = ramoops_get_next_prz(cxt->fprzs,
303 						&cxt->ftrace_read_cnt,
304 						cxt->max_ftrace_cnt, id,
305 						type, PSTORE_TYPE_FTRACE, 0);
306 
307 				if (!prz_ok(prz_next))
308 					continue;
309 
310 				tmp_prz->ecc_info = prz_next->ecc_info;
311 				tmp_prz->corrected_bytes +=
312 						prz_next->corrected_bytes;
313 				tmp_prz->bad_blocks += prz_next->bad_blocks;
314 				size = ftrace_log_combine(tmp_prz, prz_next);
315 				if (size)
316 					goto out;
317 			}
318 			*id = 0;
319 			prz = tmp_prz;
320 		}
321 	}
322 
323 	if (!prz_ok(prz)) {
324 		size = 0;
325 		goto out;
326 	}
327 
328 	size = persistent_ram_old_size(prz) - header_length;
329 
330 	/* ECC correction notice */
331 	*ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
332 
333 	*buf = kmalloc(size + *ecc_notice_size + 1, GFP_KERNEL);
334 	if (*buf == NULL) {
335 		size = -ENOMEM;
336 		goto out;
337 	}
338 
339 	memcpy(*buf, (char *)persistent_ram_old(prz) + header_length, size);
340 
341 	persistent_ram_ecc_string(prz, *buf + size, *ecc_notice_size + 1);
342 
343 out:
344 	if (free_prz) {
345 		kfree(prz->old_log);
346 		kfree(prz);
347 	}
348 
349 	return size;
350 }
351 
352 static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz,
353 				     bool compressed)
354 {
355 	char *hdr;
356 	struct timespec timestamp;
357 	size_t len;
358 
359 	/* Report zeroed timestamp if called before timekeeping has resumed. */
360 	if (__getnstimeofday(&timestamp)) {
361 		timestamp.tv_sec = 0;
362 		timestamp.tv_nsec = 0;
363 	}
364 	hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu-%c\n",
365 		(long)timestamp.tv_sec, (long)(timestamp.tv_nsec / 1000),
366 		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_buf(enum pstore_type_id type,
376 					    enum kmsg_dump_reason reason,
377 					    u64 *id, unsigned int part,
378 					    const char *buf,
379 					    bool compressed, size_t size,
380 					    struct pstore_info *psi)
381 {
382 	struct ramoops_context *cxt = psi->data;
383 	struct persistent_ram_zone *prz;
384 	size_t hlen;
385 
386 	if (type == PSTORE_TYPE_CONSOLE) {
387 		if (!cxt->cprz)
388 			return -ENOMEM;
389 		persistent_ram_write(cxt->cprz, buf, size);
390 		return 0;
391 	} else if (type == PSTORE_TYPE_FTRACE) {
392 		int zonenum;
393 
394 		if (!cxt->fprzs)
395 			return -ENOMEM;
396 		/*
397 		 * Choose zone by if we're using per-cpu buffers.
398 		 */
399 		if (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
400 			zonenum = smp_processor_id();
401 		else
402 			zonenum = 0;
403 
404 		persistent_ram_write(cxt->fprzs[zonenum], buf, size);
405 		return 0;
406 	} else if (type == PSTORE_TYPE_PMSG) {
407 		pr_warn_ratelimited("PMSG shouldn't call %s\n", __func__);
408 		return -EINVAL;
409 	}
410 
411 	if (type != PSTORE_TYPE_DMESG)
412 		return -EINVAL;
413 
414 	/* Out of the various dmesg dump types, ramoops is currently designed
415 	 * to only store crash logs, rather than storing general kernel logs.
416 	 */
417 	if (reason != KMSG_DUMP_OOPS &&
418 	    reason != KMSG_DUMP_PANIC)
419 		return -EINVAL;
420 
421 	/* Skip Oopes when configured to do so. */
422 	if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
423 		return -EINVAL;
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 (part != 1)
431 		return -ENOSPC;
432 
433 	if (!cxt->dprzs)
434 		return -ENOSPC;
435 
436 	prz = cxt->dprzs[cxt->dump_write_cnt];
437 
438 	hlen = ramoops_write_kmsg_hdr(prz, compressed);
439 	if (size + hlen > prz->buffer_size)
440 		size = prz->buffer_size - hlen;
441 	persistent_ram_write(prz, 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_buf_user(enum pstore_type_id type,
449 						 enum kmsg_dump_reason reason,
450 						 u64 *id, unsigned int part,
451 						 const char __user *buf,
452 						 bool compressed, size_t size,
453 						 struct pstore_info *psi)
454 {
455 	if (type == PSTORE_TYPE_PMSG) {
456 		struct ramoops_context *cxt = psi->data;
457 
458 		if (!cxt->mprz)
459 			return -ENOMEM;
460 		return persistent_ram_write_user(cxt->mprz, buf, size);
461 	}
462 
463 	return -EINVAL;
464 }
465 
466 static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, int count,
467 				struct timespec time, struct pstore_info *psi)
468 {
469 	struct ramoops_context *cxt = psi->data;
470 	struct persistent_ram_zone *prz;
471 
472 	switch (type) {
473 	case PSTORE_TYPE_DMESG:
474 		if (id >= cxt->max_dump_cnt)
475 			return -EINVAL;
476 		prz = cxt->dprzs[id];
477 		break;
478 	case PSTORE_TYPE_CONSOLE:
479 		prz = cxt->cprz;
480 		break;
481 	case PSTORE_TYPE_FTRACE:
482 		if (id >= cxt->max_ftrace_cnt)
483 			return -EINVAL;
484 		prz = cxt->fprzs[id];
485 		break;
486 	case PSTORE_TYPE_PMSG:
487 		prz = cxt->mprz;
488 		break;
489 	default:
490 		return -EINVAL;
491 	}
492 
493 	persistent_ram_free_old(prz);
494 	persistent_ram_zap(prz);
495 
496 	return 0;
497 }
498 
499 static struct ramoops_context oops_cxt = {
500 	.pstore = {
501 		.owner	= THIS_MODULE,
502 		.name	= "ramoops",
503 		.open	= ramoops_pstore_open,
504 		.read	= ramoops_pstore_read,
505 		.write_buf	= ramoops_pstore_write_buf,
506 		.write_buf_user	= ramoops_pstore_write_buf_user,
507 		.erase	= ramoops_pstore_erase,
508 	},
509 };
510 
511 static void ramoops_free_przs(struct ramoops_context *cxt)
512 {
513 	int i;
514 
515 	/* Free dump PRZs */
516 	if (cxt->dprzs) {
517 		for (i = 0; i < cxt->max_dump_cnt; i++)
518 			persistent_ram_free(cxt->dprzs[i]);
519 
520 		kfree(cxt->dprzs);
521 		cxt->max_dump_cnt = 0;
522 	}
523 
524 	/* Free ftrace PRZs */
525 	if (cxt->fprzs) {
526 		for (i = 0; i < cxt->max_ftrace_cnt; i++)
527 			persistent_ram_free(cxt->fprzs[i]);
528 		kfree(cxt->fprzs);
529 		cxt->max_ftrace_cnt = 0;
530 	}
531 }
532 
533 static int ramoops_init_przs(const char *name,
534 			     struct device *dev, struct ramoops_context *cxt,
535 			     struct persistent_ram_zone ***przs,
536 			     phys_addr_t *paddr, size_t mem_sz,
537 			     ssize_t record_size,
538 			     unsigned int *cnt, u32 sig, u32 flags)
539 {
540 	int err = -ENOMEM;
541 	int i;
542 	size_t zone_sz;
543 	struct persistent_ram_zone **prz_ar;
544 
545 	/* Allocate nothing for 0 mem_sz or 0 record_size. */
546 	if (mem_sz == 0 || record_size == 0) {
547 		*cnt = 0;
548 		return 0;
549 	}
550 
551 	/*
552 	 * If we have a negative record size, calculate it based on
553 	 * mem_sz / *cnt. If we have a positive record size, calculate
554 	 * cnt from mem_sz / record_size.
555 	 */
556 	if (record_size < 0) {
557 		if (*cnt == 0)
558 			return 0;
559 		record_size = mem_sz / *cnt;
560 		if (record_size == 0) {
561 			dev_err(dev, "%s record size == 0 (%zu / %u)\n",
562 				name, mem_sz, *cnt);
563 			goto fail;
564 		}
565 	} else {
566 		*cnt = mem_sz / record_size;
567 		if (*cnt == 0) {
568 			dev_err(dev, "%s record count == 0 (%zu / %zu)\n",
569 				name, mem_sz, record_size);
570 			goto fail;
571 		}
572 	}
573 
574 	if (*paddr + mem_sz - cxt->phys_addr > cxt->size) {
575 		dev_err(dev, "no room for %s mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
576 			name,
577 			mem_sz, (unsigned long long)*paddr,
578 			cxt->size, (unsigned long long)cxt->phys_addr);
579 		goto fail;
580 	}
581 
582 	zone_sz = mem_sz / *cnt;
583 	if (!zone_sz) {
584 		dev_err(dev, "%s zone size == 0\n", name);
585 		goto fail;
586 	}
587 
588 	prz_ar = kcalloc(*cnt, sizeof(**przs), GFP_KERNEL);
589 	if (!prz_ar)
590 		goto fail;
591 
592 	for (i = 0; i < *cnt; i++) {
593 		prz_ar[i] = persistent_ram_new(*paddr, zone_sz, sig,
594 						  &cxt->ecc_info,
595 						  cxt->memtype, flags);
596 		if (IS_ERR(prz_ar[i])) {
597 			err = PTR_ERR(prz_ar[i]);
598 			dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
599 				name, record_size,
600 				(unsigned long long)*paddr, err);
601 
602 			while (i > 0) {
603 				i--;
604 				persistent_ram_free(prz_ar[i]);
605 			}
606 			kfree(prz_ar);
607 			goto fail;
608 		}
609 		*paddr += zone_sz;
610 	}
611 
612 	*przs = prz_ar;
613 	return 0;
614 
615 fail:
616 	*cnt = 0;
617 	return err;
618 }
619 
620 static int ramoops_init_prz(const char *name,
621 			    struct device *dev, struct ramoops_context *cxt,
622 			    struct persistent_ram_zone **prz,
623 			    phys_addr_t *paddr, size_t sz, u32 sig)
624 {
625 	if (!sz)
626 		return 0;
627 
628 	if (*paddr + sz - cxt->phys_addr > cxt->size) {
629 		dev_err(dev, "no room for %s mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
630 			name, sz, (unsigned long long)*paddr,
631 			cxt->size, (unsigned long long)cxt->phys_addr);
632 		return -ENOMEM;
633 	}
634 
635 	*prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info,
636 				  cxt->memtype, 0);
637 	if (IS_ERR(*prz)) {
638 		int err = PTR_ERR(*prz);
639 
640 		dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
641 			name, sz, (unsigned long long)*paddr, err);
642 		return err;
643 	}
644 
645 	persistent_ram_zap(*prz);
646 
647 	*paddr += sz;
648 
649 	return 0;
650 }
651 
652 static int ramoops_parse_dt_size(struct platform_device *pdev,
653 				 const char *propname, u32 *value)
654 {
655 	u32 val32 = 0;
656 	int ret;
657 
658 	ret = of_property_read_u32(pdev->dev.of_node, propname, &val32);
659 	if (ret < 0 && ret != -EINVAL) {
660 		dev_err(&pdev->dev, "failed to parse property %s: %d\n",
661 			propname, ret);
662 		return ret;
663 	}
664 
665 	if (val32 > INT_MAX) {
666 		dev_err(&pdev->dev, "%s %u > INT_MAX\n", propname, val32);
667 		return -EOVERFLOW;
668 	}
669 
670 	*value = val32;
671 	return 0;
672 }
673 
674 static int ramoops_parse_dt(struct platform_device *pdev,
675 			    struct ramoops_platform_data *pdata)
676 {
677 	struct device_node *of_node = pdev->dev.of_node;
678 	struct resource *res;
679 	u32 value;
680 	int ret;
681 
682 	dev_dbg(&pdev->dev, "using Device Tree\n");
683 
684 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
685 	if (!res) {
686 		dev_err(&pdev->dev,
687 			"failed to locate DT /reserved-memory resource\n");
688 		return -EINVAL;
689 	}
690 
691 	pdata->mem_size = resource_size(res);
692 	pdata->mem_address = res->start;
693 	pdata->mem_type = of_property_read_bool(of_node, "unbuffered");
694 	pdata->dump_oops = !of_property_read_bool(of_node, "no-dump-oops");
695 
696 #define parse_size(name, field) {					\
697 		ret = ramoops_parse_dt_size(pdev, name, &value);	\
698 		if (ret < 0)						\
699 			return ret;					\
700 		field = value;						\
701 	}
702 
703 	parse_size("record-size", pdata->record_size);
704 	parse_size("console-size", pdata->console_size);
705 	parse_size("ftrace-size", pdata->ftrace_size);
706 	parse_size("pmsg-size", pdata->pmsg_size);
707 	parse_size("ecc-size", pdata->ecc_info.ecc_size);
708 	parse_size("flags", pdata->flags);
709 
710 #undef parse_size
711 
712 	return 0;
713 }
714 
715 static int ramoops_probe(struct platform_device *pdev)
716 {
717 	struct device *dev = &pdev->dev;
718 	struct ramoops_platform_data *pdata = dev->platform_data;
719 	struct ramoops_context *cxt = &oops_cxt;
720 	size_t dump_mem_sz;
721 	phys_addr_t paddr;
722 	int err = -EINVAL;
723 
724 	if (dev_of_node(dev) && !pdata) {
725 		pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
726 		if (!pdata) {
727 			pr_err("cannot allocate platform data buffer\n");
728 			err = -ENOMEM;
729 			goto fail_out;
730 		}
731 
732 		err = ramoops_parse_dt(pdev, pdata);
733 		if (err < 0)
734 			goto fail_out;
735 	}
736 
737 	/*
738 	 * Only a single ramoops area allowed at a time, so fail extra
739 	 * probes.
740 	 */
741 	if (cxt->max_dump_cnt) {
742 		pr_err("already initialized\n");
743 		goto fail_out;
744 	}
745 
746 	/* Make sure we didn't get bogus platform data pointer. */
747 	if (!pdata) {
748 		pr_err("NULL platform data\n");
749 		goto fail_out;
750 	}
751 
752 	if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size &&
753 			!pdata->ftrace_size && !pdata->pmsg_size)) {
754 		pr_err("The memory size and the record/console size must be "
755 			"non-zero\n");
756 		goto fail_out;
757 	}
758 
759 	if (pdata->record_size && !is_power_of_2(pdata->record_size))
760 		pdata->record_size = rounddown_pow_of_two(pdata->record_size);
761 	if (pdata->console_size && !is_power_of_2(pdata->console_size))
762 		pdata->console_size = rounddown_pow_of_two(pdata->console_size);
763 	if (pdata->ftrace_size && !is_power_of_2(pdata->ftrace_size))
764 		pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
765 	if (pdata->pmsg_size && !is_power_of_2(pdata->pmsg_size))
766 		pdata->pmsg_size = rounddown_pow_of_two(pdata->pmsg_size);
767 
768 	cxt->size = pdata->mem_size;
769 	cxt->phys_addr = pdata->mem_address;
770 	cxt->memtype = pdata->mem_type;
771 	cxt->record_size = pdata->record_size;
772 	cxt->console_size = pdata->console_size;
773 	cxt->ftrace_size = pdata->ftrace_size;
774 	cxt->pmsg_size = pdata->pmsg_size;
775 	cxt->dump_oops = pdata->dump_oops;
776 	cxt->flags = pdata->flags;
777 	cxt->ecc_info = pdata->ecc_info;
778 
779 	paddr = cxt->phys_addr;
780 
781 	dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size
782 			- cxt->pmsg_size;
783 	err = ramoops_init_przs("dump", dev, cxt, &cxt->dprzs, &paddr,
784 				dump_mem_sz, cxt->record_size,
785 				&cxt->max_dump_cnt, 0, 0);
786 	if (err)
787 		goto fail_out;
788 
789 	err = ramoops_init_prz("console", dev, cxt, &cxt->cprz, &paddr,
790 			       cxt->console_size, 0);
791 	if (err)
792 		goto fail_init_cprz;
793 
794 	cxt->max_ftrace_cnt = (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
795 				? nr_cpu_ids
796 				: 1;
797 	err = ramoops_init_przs("ftrace", dev, cxt, &cxt->fprzs, &paddr,
798 				cxt->ftrace_size, -1,
799 				&cxt->max_ftrace_cnt, LINUX_VERSION_CODE,
800 				(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
801 					? PRZ_FLAG_NO_LOCK : 0);
802 	if (err)
803 		goto fail_init_fprz;
804 
805 	err = ramoops_init_prz("pmsg", dev, cxt, &cxt->mprz, &paddr,
806 				cxt->pmsg_size, 0);
807 	if (err)
808 		goto fail_init_mprz;
809 
810 	cxt->pstore.data = cxt;
811 	/*
812 	 * Console can handle any buffer size, so prefer LOG_LINE_MAX. If we
813 	 * have to handle dumps, we must have at least record_size buffer. And
814 	 * for ftrace, bufsize is irrelevant (if bufsize is 0, buf will be
815 	 * ZERO_SIZE_PTR).
816 	 */
817 	if (cxt->console_size)
818 		cxt->pstore.bufsize = 1024; /* LOG_LINE_MAX */
819 	cxt->pstore.bufsize = max(cxt->record_size, cxt->pstore.bufsize);
820 	cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
821 	if (!cxt->pstore.buf) {
822 		pr_err("cannot allocate pstore buffer\n");
823 		err = -ENOMEM;
824 		goto fail_clear;
825 	}
826 	spin_lock_init(&cxt->pstore.buf_lock);
827 
828 	cxt->pstore.flags = PSTORE_FLAGS_DMESG;
829 	if (cxt->console_size)
830 		cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE;
831 	if (cxt->ftrace_size)
832 		cxt->pstore.flags |= PSTORE_FLAGS_FTRACE;
833 	if (cxt->pmsg_size)
834 		cxt->pstore.flags |= PSTORE_FLAGS_PMSG;
835 
836 	err = pstore_register(&cxt->pstore);
837 	if (err) {
838 		pr_err("registering with pstore failed\n");
839 		goto fail_buf;
840 	}
841 
842 	/*
843 	 * Update the module parameter variables as well so they are visible
844 	 * through /sys/module/ramoops/parameters/
845 	 */
846 	mem_size = pdata->mem_size;
847 	mem_address = pdata->mem_address;
848 	record_size = pdata->record_size;
849 	dump_oops = pdata->dump_oops;
850 	ramoops_console_size = pdata->console_size;
851 	ramoops_pmsg_size = pdata->pmsg_size;
852 	ramoops_ftrace_size = pdata->ftrace_size;
853 
854 	pr_info("attached 0x%lx@0x%llx, ecc: %d/%d\n",
855 		cxt->size, (unsigned long long)cxt->phys_addr,
856 		cxt->ecc_info.ecc_size, cxt->ecc_info.block_size);
857 
858 	return 0;
859 
860 fail_buf:
861 	kfree(cxt->pstore.buf);
862 fail_clear:
863 	cxt->pstore.bufsize = 0;
864 	persistent_ram_free(cxt->mprz);
865 fail_init_mprz:
866 fail_init_fprz:
867 	persistent_ram_free(cxt->cprz);
868 fail_init_cprz:
869 	ramoops_free_przs(cxt);
870 fail_out:
871 	return err;
872 }
873 
874 static int ramoops_remove(struct platform_device *pdev)
875 {
876 	struct ramoops_context *cxt = &oops_cxt;
877 
878 	pstore_unregister(&cxt->pstore);
879 
880 	kfree(cxt->pstore.buf);
881 	cxt->pstore.bufsize = 0;
882 
883 	persistent_ram_free(cxt->mprz);
884 	persistent_ram_free(cxt->cprz);
885 	ramoops_free_przs(cxt);
886 
887 	return 0;
888 }
889 
890 static const struct of_device_id dt_match[] = {
891 	{ .compatible = "ramoops" },
892 	{}
893 };
894 
895 static struct platform_driver ramoops_driver = {
896 	.probe		= ramoops_probe,
897 	.remove		= ramoops_remove,
898 	.driver		= {
899 		.name		= "ramoops",
900 		.of_match_table	= dt_match,
901 	},
902 };
903 
904 static void ramoops_register_dummy(void)
905 {
906 	if (!mem_size)
907 		return;
908 
909 	pr_info("using module parameters\n");
910 
911 	dummy_data = kzalloc(sizeof(*dummy_data), GFP_KERNEL);
912 	if (!dummy_data) {
913 		pr_info("could not allocate pdata\n");
914 		return;
915 	}
916 
917 	dummy_data->mem_size = mem_size;
918 	dummy_data->mem_address = mem_address;
919 	dummy_data->mem_type = mem_type;
920 	dummy_data->record_size = record_size;
921 	dummy_data->console_size = ramoops_console_size;
922 	dummy_data->ftrace_size = ramoops_ftrace_size;
923 	dummy_data->pmsg_size = ramoops_pmsg_size;
924 	dummy_data->dump_oops = dump_oops;
925 	dummy_data->flags = RAMOOPS_FLAG_FTRACE_PER_CPU;
926 
927 	/*
928 	 * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
929 	 * (using 1 byte for ECC isn't much of use anyway).
930 	 */
931 	dummy_data->ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
932 
933 	dummy = platform_device_register_data(NULL, "ramoops", -1,
934 			dummy_data, sizeof(struct ramoops_platform_data));
935 	if (IS_ERR(dummy)) {
936 		pr_info("could not create platform device: %ld\n",
937 			PTR_ERR(dummy));
938 	}
939 }
940 
941 static int __init ramoops_init(void)
942 {
943 	ramoops_register_dummy();
944 	return platform_driver_register(&ramoops_driver);
945 }
946 postcore_initcall(ramoops_init);
947 
948 static void __exit ramoops_exit(void)
949 {
950 	platform_driver_unregister(&ramoops_driver);
951 	platform_device_unregister(dummy);
952 	kfree(dummy_data);
953 }
954 module_exit(ramoops_exit);
955 
956 MODULE_LICENSE("GPL");
957 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
958 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");
959