xref: /openbmc/linux/fs/pstore/ram.c (revision 04dc82e1)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * RAM Oops/Panic logger
4  *
5  * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
6  * Copyright (C) 2011 Kees Cook <keescook@chromium.org>
7  */
8 
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10 
11 #include <linux/kernel.h>
12 #include <linux/err.h>
13 #include <linux/module.h>
14 #include <linux/version.h>
15 #include <linux/pstore.h>
16 #include <linux/io.h>
17 #include <linux/ioport.h>
18 #include <linux/platform_device.h>
19 #include <linux/slab.h>
20 #include <linux/compiler.h>
21 #include <linux/pstore_ram.h>
22 #include <linux/of.h>
23 #include <linux/of_address.h>
24 
25 #define RAMOOPS_KERNMSG_HDR "===="
26 #define MIN_MEM_SIZE 4096UL
27 
28 static ulong record_size = MIN_MEM_SIZE;
29 module_param(record_size, ulong, 0400);
30 MODULE_PARM_DESC(record_size,
31 		"size of each dump done on oops/panic");
32 
33 static ulong ramoops_console_size = MIN_MEM_SIZE;
34 module_param_named(console_size, ramoops_console_size, ulong, 0400);
35 MODULE_PARM_DESC(console_size, "size of kernel console log");
36 
37 static ulong ramoops_ftrace_size = MIN_MEM_SIZE;
38 module_param_named(ftrace_size, ramoops_ftrace_size, ulong, 0400);
39 MODULE_PARM_DESC(ftrace_size, "size of ftrace log");
40 
41 static ulong ramoops_pmsg_size = MIN_MEM_SIZE;
42 module_param_named(pmsg_size, ramoops_pmsg_size, ulong, 0400);
43 MODULE_PARM_DESC(pmsg_size, "size of user space message log");
44 
45 static unsigned long long mem_address;
46 module_param_hw(mem_address, ullong, other, 0400);
47 MODULE_PARM_DESC(mem_address,
48 		"start of reserved RAM used to store oops/panic logs");
49 
50 static ulong mem_size;
51 module_param(mem_size, ulong, 0400);
52 MODULE_PARM_DESC(mem_size,
53 		"size of reserved RAM used to store oops/panic logs");
54 
55 static unsigned int mem_type;
56 module_param(mem_type, uint, 0600);
57 MODULE_PARM_DESC(mem_type,
58 		"set to 1 to try to use unbuffered memory (default 0)");
59 
60 static int dump_oops = 1;
61 module_param(dump_oops, int, 0600);
62 MODULE_PARM_DESC(dump_oops,
63 		"set to 1 to dump oopses, 0 to only dump panics (default 1)");
64 
65 static int ramoops_ecc;
66 module_param_named(ecc, ramoops_ecc, int, 0600);
67 MODULE_PARM_DESC(ramoops_ecc,
68 		"if non-zero, the option enables ECC support and specifies "
69 		"ECC buffer size in bytes (1 is a special value, means 16 "
70 		"bytes ECC)");
71 
72 struct ramoops_context {
73 	struct persistent_ram_zone **dprzs;	/* Oops dump zones */
74 	struct persistent_ram_zone *cprz;	/* Console zone */
75 	struct persistent_ram_zone **fprzs;	/* Ftrace zones */
76 	struct persistent_ram_zone *mprz;	/* PMSG zone */
77 	phys_addr_t phys_addr;
78 	unsigned long size;
79 	unsigned int memtype;
80 	size_t record_size;
81 	size_t console_size;
82 	size_t ftrace_size;
83 	size_t pmsg_size;
84 	int dump_oops;
85 	u32 flags;
86 	struct persistent_ram_ecc_info ecc_info;
87 	unsigned int max_dump_cnt;
88 	unsigned int dump_write_cnt;
89 	/* _read_cnt need clear on ramoops_pstore_open */
90 	unsigned int dump_read_cnt;
91 	unsigned int console_read_cnt;
92 	unsigned int max_ftrace_cnt;
93 	unsigned int ftrace_read_cnt;
94 	unsigned int pmsg_read_cnt;
95 	struct pstore_info pstore;
96 };
97 
98 static struct platform_device *dummy;
99 
100 static int ramoops_pstore_open(struct pstore_info *psi)
101 {
102 	struct ramoops_context *cxt = psi->data;
103 
104 	cxt->dump_read_cnt = 0;
105 	cxt->console_read_cnt = 0;
106 	cxt->ftrace_read_cnt = 0;
107 	cxt->pmsg_read_cnt = 0;
108 	return 0;
109 }
110 
111 static struct persistent_ram_zone *
112 ramoops_get_next_prz(struct persistent_ram_zone *przs[], int id,
113 		     struct pstore_record *record)
114 {
115 	struct persistent_ram_zone *prz;
116 
117 	/* Give up if we never existed or have hit the end. */
118 	if (!przs)
119 		return NULL;
120 
121 	prz = przs[id];
122 	if (!prz)
123 		return NULL;
124 
125 	/* Update old/shadowed buffer. */
126 	if (prz->type == PSTORE_TYPE_DMESG)
127 		persistent_ram_save_old(prz);
128 
129 	if (!persistent_ram_old_size(prz))
130 		return NULL;
131 
132 	record->type = prz->type;
133 	record->id = id;
134 
135 	return prz;
136 }
137 
138 static int ramoops_read_kmsg_hdr(char *buffer, struct timespec64 *time,
139 				  bool *compressed)
140 {
141 	char data_type;
142 	int header_length = 0;
143 
144 	if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lld.%lu-%c\n%n",
145 		   (time64_t *)&time->tv_sec, &time->tv_nsec, &data_type,
146 		   &header_length) == 3) {
147 		if (data_type == 'C')
148 			*compressed = true;
149 		else
150 			*compressed = false;
151 	} else if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lld.%lu\n%n",
152 			  (time64_t *)&time->tv_sec, &time->tv_nsec,
153 			  &header_length) == 2) {
154 		*compressed = false;
155 	} else {
156 		time->tv_sec = 0;
157 		time->tv_nsec = 0;
158 		*compressed = false;
159 	}
160 	return header_length;
161 }
162 
163 static bool prz_ok(struct persistent_ram_zone *prz)
164 {
165 	return !!prz && !!(persistent_ram_old_size(prz) +
166 			   persistent_ram_ecc_string(prz, NULL, 0));
167 }
168 
169 static ssize_t ftrace_log_combine(struct persistent_ram_zone *dest,
170 				  struct persistent_ram_zone *src)
171 {
172 	size_t dest_size, src_size, total, dest_off, src_off;
173 	size_t dest_idx = 0, src_idx = 0, merged_idx = 0;
174 	void *merged_buf;
175 	struct pstore_ftrace_record *drec, *srec, *mrec;
176 	size_t record_size = sizeof(struct pstore_ftrace_record);
177 
178 	dest_off = dest->old_log_size % record_size;
179 	dest_size = dest->old_log_size - dest_off;
180 
181 	src_off = src->old_log_size % record_size;
182 	src_size = src->old_log_size - src_off;
183 
184 	total = dest_size + src_size;
185 	merged_buf = kmalloc(total, GFP_KERNEL);
186 	if (!merged_buf)
187 		return -ENOMEM;
188 
189 	drec = (struct pstore_ftrace_record *)(dest->old_log + dest_off);
190 	srec = (struct pstore_ftrace_record *)(src->old_log + src_off);
191 	mrec = (struct pstore_ftrace_record *)(merged_buf);
192 
193 	while (dest_size > 0 && src_size > 0) {
194 		if (pstore_ftrace_read_timestamp(&drec[dest_idx]) <
195 		    pstore_ftrace_read_timestamp(&srec[src_idx])) {
196 			mrec[merged_idx++] = drec[dest_idx++];
197 			dest_size -= record_size;
198 		} else {
199 			mrec[merged_idx++] = srec[src_idx++];
200 			src_size -= record_size;
201 		}
202 	}
203 
204 	while (dest_size > 0) {
205 		mrec[merged_idx++] = drec[dest_idx++];
206 		dest_size -= record_size;
207 	}
208 
209 	while (src_size > 0) {
210 		mrec[merged_idx++] = srec[src_idx++];
211 		src_size -= record_size;
212 	}
213 
214 	kfree(dest->old_log);
215 	dest->old_log = merged_buf;
216 	dest->old_log_size = total;
217 
218 	return 0;
219 }
220 
221 static ssize_t ramoops_pstore_read(struct pstore_record *record)
222 {
223 	ssize_t size = 0;
224 	struct ramoops_context *cxt = record->psi->data;
225 	struct persistent_ram_zone *prz = NULL;
226 	int header_length = 0;
227 	bool free_prz = false;
228 
229 	/*
230 	 * Ramoops headers provide time stamps for PSTORE_TYPE_DMESG, but
231 	 * PSTORE_TYPE_CONSOLE and PSTORE_TYPE_FTRACE don't currently have
232 	 * valid time stamps, so it is initialized to zero.
233 	 */
234 	record->time.tv_sec = 0;
235 	record->time.tv_nsec = 0;
236 	record->compressed = false;
237 
238 	/* Find the next valid persistent_ram_zone for DMESG */
239 	while (cxt->dump_read_cnt < cxt->max_dump_cnt && !prz) {
240 		prz = ramoops_get_next_prz(cxt->dprzs, cxt->dump_read_cnt++,
241 					   record);
242 		if (!prz_ok(prz))
243 			continue;
244 		header_length = ramoops_read_kmsg_hdr(persistent_ram_old(prz),
245 						      &record->time,
246 						      &record->compressed);
247 		/* Clear and skip this DMESG record if it has no valid header */
248 		if (!header_length) {
249 			persistent_ram_free_old(prz);
250 			persistent_ram_zap(prz);
251 			prz = NULL;
252 		}
253 	}
254 
255 	if (!prz_ok(prz) && !cxt->console_read_cnt++)
256 		prz = ramoops_get_next_prz(&cxt->cprz, 0 /* single */, record);
257 
258 	if (!prz_ok(prz) && !cxt->pmsg_read_cnt++)
259 		prz = ramoops_get_next_prz(&cxt->mprz, 0 /* single */, record);
260 
261 	/* ftrace is last since it may want to dynamically allocate memory. */
262 	if (!prz_ok(prz)) {
263 		if (!(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU) &&
264 		    !cxt->ftrace_read_cnt++) {
265 			prz = ramoops_get_next_prz(cxt->fprzs, 0 /* single */,
266 						   record);
267 		} else {
268 			/*
269 			 * Build a new dummy record which combines all the
270 			 * per-cpu records including metadata and ecc info.
271 			 */
272 			struct persistent_ram_zone *tmp_prz, *prz_next;
273 
274 			tmp_prz = kzalloc(sizeof(struct persistent_ram_zone),
275 					  GFP_KERNEL);
276 			if (!tmp_prz)
277 				return -ENOMEM;
278 			prz = tmp_prz;
279 			free_prz = true;
280 
281 			while (cxt->ftrace_read_cnt < cxt->max_ftrace_cnt) {
282 				prz_next = ramoops_get_next_prz(cxt->fprzs,
283 						cxt->ftrace_read_cnt++, record);
284 
285 				if (!prz_ok(prz_next))
286 					continue;
287 
288 				tmp_prz->ecc_info = prz_next->ecc_info;
289 				tmp_prz->corrected_bytes +=
290 						prz_next->corrected_bytes;
291 				tmp_prz->bad_blocks += prz_next->bad_blocks;
292 				size = ftrace_log_combine(tmp_prz, prz_next);
293 				if (size)
294 					goto out;
295 			}
296 			record->id = 0;
297 		}
298 	}
299 
300 	if (!prz_ok(prz)) {
301 		size = 0;
302 		goto out;
303 	}
304 
305 	size = persistent_ram_old_size(prz) - header_length;
306 
307 	/* ECC correction notice */
308 	record->ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
309 
310 	record->buf = kmalloc(size + record->ecc_notice_size + 1, GFP_KERNEL);
311 	if (record->buf == NULL) {
312 		size = -ENOMEM;
313 		goto out;
314 	}
315 
316 	memcpy(record->buf, (char *)persistent_ram_old(prz) + header_length,
317 	       size);
318 
319 	persistent_ram_ecc_string(prz, record->buf + size,
320 				  record->ecc_notice_size + 1);
321 
322 out:
323 	if (free_prz) {
324 		kfree(prz->old_log);
325 		kfree(prz);
326 	}
327 
328 	return size;
329 }
330 
331 static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz,
332 				     struct pstore_record *record)
333 {
334 	char hdr[36]; /* "===="(4), %lld(20), "."(1), %06lu(6), "-%c\n"(3) */
335 	size_t len;
336 
337 	len = scnprintf(hdr, sizeof(hdr),
338 		RAMOOPS_KERNMSG_HDR "%lld.%06lu-%c\n",
339 		(time64_t)record->time.tv_sec,
340 		record->time.tv_nsec / 1000,
341 		record->compressed ? 'C' : 'D');
342 	persistent_ram_write(prz, hdr, len);
343 
344 	return len;
345 }
346 
347 static int notrace ramoops_pstore_write(struct pstore_record *record)
348 {
349 	struct ramoops_context *cxt = record->psi->data;
350 	struct persistent_ram_zone *prz;
351 	size_t size, hlen;
352 
353 	if (record->type == PSTORE_TYPE_CONSOLE) {
354 		if (!cxt->cprz)
355 			return -ENOMEM;
356 		persistent_ram_write(cxt->cprz, record->buf, record->size);
357 		return 0;
358 	} else if (record->type == PSTORE_TYPE_FTRACE) {
359 		int zonenum;
360 
361 		if (!cxt->fprzs)
362 			return -ENOMEM;
363 		/*
364 		 * Choose zone by if we're using per-cpu buffers.
365 		 */
366 		if (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
367 			zonenum = smp_processor_id();
368 		else
369 			zonenum = 0;
370 
371 		persistent_ram_write(cxt->fprzs[zonenum], record->buf,
372 				     record->size);
373 		return 0;
374 	} else if (record->type == PSTORE_TYPE_PMSG) {
375 		pr_warn_ratelimited("PMSG shouldn't call %s\n", __func__);
376 		return -EINVAL;
377 	}
378 
379 	if (record->type != PSTORE_TYPE_DMESG)
380 		return -EINVAL;
381 
382 	/*
383 	 * Out of the various dmesg dump types, ramoops is currently designed
384 	 * to only store crash logs, rather than storing general kernel logs.
385 	 */
386 	if (record->reason != KMSG_DUMP_OOPS &&
387 	    record->reason != KMSG_DUMP_PANIC)
388 		return -EINVAL;
389 
390 	/* Skip Oopes when configured to do so. */
391 	if (record->reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
392 		return -EINVAL;
393 
394 	/*
395 	 * Explicitly only take the first part of any new crash.
396 	 * If our buffer is larger than kmsg_bytes, this can never happen,
397 	 * and if our buffer is smaller than kmsg_bytes, we don't want the
398 	 * report split across multiple records.
399 	 */
400 	if (record->part != 1)
401 		return -ENOSPC;
402 
403 	if (!cxt->dprzs)
404 		return -ENOSPC;
405 
406 	prz = cxt->dprzs[cxt->dump_write_cnt];
407 
408 	/* Build header and append record contents. */
409 	hlen = ramoops_write_kmsg_hdr(prz, record);
410 	if (!hlen)
411 		return -ENOMEM;
412 
413 	size = record->size;
414 	if (size + hlen > prz->buffer_size)
415 		size = prz->buffer_size - hlen;
416 	persistent_ram_write(prz, record->buf, size);
417 
418 	cxt->dump_write_cnt = (cxt->dump_write_cnt + 1) % cxt->max_dump_cnt;
419 
420 	return 0;
421 }
422 
423 static int notrace ramoops_pstore_write_user(struct pstore_record *record,
424 					     const char __user *buf)
425 {
426 	if (record->type == PSTORE_TYPE_PMSG) {
427 		struct ramoops_context *cxt = record->psi->data;
428 
429 		if (!cxt->mprz)
430 			return -ENOMEM;
431 		return persistent_ram_write_user(cxt->mprz, buf, record->size);
432 	}
433 
434 	return -EINVAL;
435 }
436 
437 static int ramoops_pstore_erase(struct pstore_record *record)
438 {
439 	struct ramoops_context *cxt = record->psi->data;
440 	struct persistent_ram_zone *prz;
441 
442 	switch (record->type) {
443 	case PSTORE_TYPE_DMESG:
444 		if (record->id >= cxt->max_dump_cnt)
445 			return -EINVAL;
446 		prz = cxt->dprzs[record->id];
447 		break;
448 	case PSTORE_TYPE_CONSOLE:
449 		prz = cxt->cprz;
450 		break;
451 	case PSTORE_TYPE_FTRACE:
452 		if (record->id >= cxt->max_ftrace_cnt)
453 			return -EINVAL;
454 		prz = cxt->fprzs[record->id];
455 		break;
456 	case PSTORE_TYPE_PMSG:
457 		prz = cxt->mprz;
458 		break;
459 	default:
460 		return -EINVAL;
461 	}
462 
463 	persistent_ram_free_old(prz);
464 	persistent_ram_zap(prz);
465 
466 	return 0;
467 }
468 
469 static struct ramoops_context oops_cxt = {
470 	.pstore = {
471 		.owner	= THIS_MODULE,
472 		.name	= "ramoops",
473 		.open	= ramoops_pstore_open,
474 		.read	= ramoops_pstore_read,
475 		.write	= ramoops_pstore_write,
476 		.write_user	= ramoops_pstore_write_user,
477 		.erase	= ramoops_pstore_erase,
478 	},
479 };
480 
481 static void ramoops_free_przs(struct ramoops_context *cxt)
482 {
483 	int i;
484 
485 	/* Free dump PRZs */
486 	if (cxt->dprzs) {
487 		for (i = 0; i < cxt->max_dump_cnt; i++)
488 			persistent_ram_free(cxt->dprzs[i]);
489 
490 		kfree(cxt->dprzs);
491 		cxt->max_dump_cnt = 0;
492 	}
493 
494 	/* Free ftrace PRZs */
495 	if (cxt->fprzs) {
496 		for (i = 0; i < cxt->max_ftrace_cnt; i++)
497 			persistent_ram_free(cxt->fprzs[i]);
498 		kfree(cxt->fprzs);
499 		cxt->max_ftrace_cnt = 0;
500 	}
501 }
502 
503 static int ramoops_init_przs(const char *name,
504 			     struct device *dev, struct ramoops_context *cxt,
505 			     struct persistent_ram_zone ***przs,
506 			     phys_addr_t *paddr, size_t mem_sz,
507 			     ssize_t record_size,
508 			     unsigned int *cnt, u32 sig, u32 flags)
509 {
510 	int err = -ENOMEM;
511 	int i;
512 	size_t zone_sz;
513 	struct persistent_ram_zone **prz_ar;
514 
515 	/* Allocate nothing for 0 mem_sz or 0 record_size. */
516 	if (mem_sz == 0 || record_size == 0) {
517 		*cnt = 0;
518 		return 0;
519 	}
520 
521 	/*
522 	 * If we have a negative record size, calculate it based on
523 	 * mem_sz / *cnt. If we have a positive record size, calculate
524 	 * cnt from mem_sz / record_size.
525 	 */
526 	if (record_size < 0) {
527 		if (*cnt == 0)
528 			return 0;
529 		record_size = mem_sz / *cnt;
530 		if (record_size == 0) {
531 			dev_err(dev, "%s record size == 0 (%zu / %u)\n",
532 				name, mem_sz, *cnt);
533 			goto fail;
534 		}
535 	} else {
536 		*cnt = mem_sz / record_size;
537 		if (*cnt == 0) {
538 			dev_err(dev, "%s record count == 0 (%zu / %zu)\n",
539 				name, mem_sz, record_size);
540 			goto fail;
541 		}
542 	}
543 
544 	if (*paddr + mem_sz - cxt->phys_addr > cxt->size) {
545 		dev_err(dev, "no room for %s mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
546 			name,
547 			mem_sz, (unsigned long long)*paddr,
548 			cxt->size, (unsigned long long)cxt->phys_addr);
549 		goto fail;
550 	}
551 
552 	zone_sz = mem_sz / *cnt;
553 	if (!zone_sz) {
554 		dev_err(dev, "%s zone size == 0\n", name);
555 		goto fail;
556 	}
557 
558 	prz_ar = kcalloc(*cnt, sizeof(**przs), GFP_KERNEL);
559 	if (!prz_ar)
560 		goto fail;
561 
562 	for (i = 0; i < *cnt; i++) {
563 		char *label;
564 
565 		if (*cnt == 1)
566 			label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
567 		else
568 			label = kasprintf(GFP_KERNEL, "ramoops:%s(%d/%d)",
569 					  name, i, *cnt - 1);
570 		prz_ar[i] = persistent_ram_new(*paddr, zone_sz, sig,
571 					       &cxt->ecc_info,
572 					       cxt->memtype, flags, label);
573 		if (IS_ERR(prz_ar[i])) {
574 			err = PTR_ERR(prz_ar[i]);
575 			dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
576 				name, record_size,
577 				(unsigned long long)*paddr, err);
578 
579 			while (i > 0) {
580 				i--;
581 				persistent_ram_free(prz_ar[i]);
582 			}
583 			kfree(prz_ar);
584 			goto fail;
585 		}
586 		*paddr += zone_sz;
587 		prz_ar[i]->type = pstore_name_to_type(name);
588 	}
589 
590 	*przs = prz_ar;
591 	return 0;
592 
593 fail:
594 	*cnt = 0;
595 	return err;
596 }
597 
598 static int ramoops_init_prz(const char *name,
599 			    struct device *dev, struct ramoops_context *cxt,
600 			    struct persistent_ram_zone **prz,
601 			    phys_addr_t *paddr, size_t sz, u32 sig)
602 {
603 	char *label;
604 
605 	if (!sz)
606 		return 0;
607 
608 	if (*paddr + sz - cxt->phys_addr > cxt->size) {
609 		dev_err(dev, "no room for %s mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
610 			name, sz, (unsigned long long)*paddr,
611 			cxt->size, (unsigned long long)cxt->phys_addr);
612 		return -ENOMEM;
613 	}
614 
615 	label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
616 	*prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info,
617 				  cxt->memtype, PRZ_FLAG_ZAP_OLD, label);
618 	if (IS_ERR(*prz)) {
619 		int err = PTR_ERR(*prz);
620 
621 		dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
622 			name, sz, (unsigned long long)*paddr, err);
623 		return err;
624 	}
625 
626 	*paddr += sz;
627 	(*prz)->type = pstore_name_to_type(name);
628 
629 	return 0;
630 }
631 
632 static int ramoops_parse_dt_size(struct platform_device *pdev,
633 				 const char *propname, u32 *value)
634 {
635 	u32 val32 = 0;
636 	int ret;
637 
638 	ret = of_property_read_u32(pdev->dev.of_node, propname, &val32);
639 	if (ret < 0 && ret != -EINVAL) {
640 		dev_err(&pdev->dev, "failed to parse property %s: %d\n",
641 			propname, ret);
642 		return ret;
643 	}
644 
645 	if (val32 > INT_MAX) {
646 		dev_err(&pdev->dev, "%s %u > INT_MAX\n", propname, val32);
647 		return -EOVERFLOW;
648 	}
649 
650 	*value = val32;
651 	return 0;
652 }
653 
654 static int ramoops_parse_dt(struct platform_device *pdev,
655 			    struct ramoops_platform_data *pdata)
656 {
657 	struct device_node *of_node = pdev->dev.of_node;
658 	struct resource *res;
659 	u32 value;
660 	int ret;
661 
662 	dev_dbg(&pdev->dev, "using Device Tree\n");
663 
664 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
665 	if (!res) {
666 		dev_err(&pdev->dev,
667 			"failed to locate DT /reserved-memory resource\n");
668 		return -EINVAL;
669 	}
670 
671 	pdata->mem_size = resource_size(res);
672 	pdata->mem_address = res->start;
673 	pdata->mem_type = of_property_read_bool(of_node, "unbuffered");
674 	pdata->dump_oops = !of_property_read_bool(of_node, "no-dump-oops");
675 
676 #define parse_size(name, field) {					\
677 		ret = ramoops_parse_dt_size(pdev, name, &value);	\
678 		if (ret < 0)						\
679 			return ret;					\
680 		field = value;						\
681 	}
682 
683 	parse_size("record-size", pdata->record_size);
684 	parse_size("console-size", pdata->console_size);
685 	parse_size("ftrace-size", pdata->ftrace_size);
686 	parse_size("pmsg-size", pdata->pmsg_size);
687 	parse_size("ecc-size", pdata->ecc_info.ecc_size);
688 	parse_size("flags", pdata->flags);
689 
690 #undef parse_size
691 
692 	return 0;
693 }
694 
695 static int ramoops_probe(struct platform_device *pdev)
696 {
697 	struct device *dev = &pdev->dev;
698 	struct ramoops_platform_data *pdata = dev->platform_data;
699 	struct ramoops_platform_data pdata_local;
700 	struct ramoops_context *cxt = &oops_cxt;
701 	size_t dump_mem_sz;
702 	phys_addr_t paddr;
703 	int err = -EINVAL;
704 
705 	/*
706 	 * Only a single ramoops area allowed at a time, so fail extra
707 	 * probes.
708 	 */
709 	if (cxt->max_dump_cnt) {
710 		pr_err("already initialized\n");
711 		goto fail_out;
712 	}
713 
714 	if (dev_of_node(dev) && !pdata) {
715 		pdata = &pdata_local;
716 		memset(pdata, 0, sizeof(*pdata));
717 
718 		err = ramoops_parse_dt(pdev, pdata);
719 		if (err < 0)
720 			goto fail_out;
721 	}
722 
723 	/* Make sure we didn't get bogus platform data pointer. */
724 	if (!pdata) {
725 		pr_err("NULL platform data\n");
726 		goto fail_out;
727 	}
728 
729 	if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size &&
730 			!pdata->ftrace_size && !pdata->pmsg_size)) {
731 		pr_err("The memory size and the record/console size must be "
732 			"non-zero\n");
733 		goto fail_out;
734 	}
735 
736 	if (pdata->record_size && !is_power_of_2(pdata->record_size))
737 		pdata->record_size = rounddown_pow_of_two(pdata->record_size);
738 	if (pdata->console_size && !is_power_of_2(pdata->console_size))
739 		pdata->console_size = rounddown_pow_of_two(pdata->console_size);
740 	if (pdata->ftrace_size && !is_power_of_2(pdata->ftrace_size))
741 		pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
742 	if (pdata->pmsg_size && !is_power_of_2(pdata->pmsg_size))
743 		pdata->pmsg_size = rounddown_pow_of_two(pdata->pmsg_size);
744 
745 	cxt->size = pdata->mem_size;
746 	cxt->phys_addr = pdata->mem_address;
747 	cxt->memtype = pdata->mem_type;
748 	cxt->record_size = pdata->record_size;
749 	cxt->console_size = pdata->console_size;
750 	cxt->ftrace_size = pdata->ftrace_size;
751 	cxt->pmsg_size = pdata->pmsg_size;
752 	cxt->dump_oops = pdata->dump_oops;
753 	cxt->flags = pdata->flags;
754 	cxt->ecc_info = pdata->ecc_info;
755 
756 	paddr = cxt->phys_addr;
757 
758 	dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size
759 			- cxt->pmsg_size;
760 	err = ramoops_init_przs("dmesg", dev, cxt, &cxt->dprzs, &paddr,
761 				dump_mem_sz, cxt->record_size,
762 				&cxt->max_dump_cnt, 0, 0);
763 	if (err)
764 		goto fail_out;
765 
766 	err = ramoops_init_prz("console", dev, cxt, &cxt->cprz, &paddr,
767 			       cxt->console_size, 0);
768 	if (err)
769 		goto fail_init_cprz;
770 
771 	cxt->max_ftrace_cnt = (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
772 				? nr_cpu_ids
773 				: 1;
774 	err = ramoops_init_przs("ftrace", dev, cxt, &cxt->fprzs, &paddr,
775 				cxt->ftrace_size, -1,
776 				&cxt->max_ftrace_cnt, LINUX_VERSION_CODE,
777 				(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
778 					? PRZ_FLAG_NO_LOCK : 0);
779 	if (err)
780 		goto fail_init_fprz;
781 
782 	err = ramoops_init_prz("pmsg", dev, cxt, &cxt->mprz, &paddr,
783 				cxt->pmsg_size, 0);
784 	if (err)
785 		goto fail_init_mprz;
786 
787 	cxt->pstore.data = cxt;
788 	/*
789 	 * Since bufsize is only used for dmesg crash dumps, it
790 	 * must match the size of the dprz record (after PRZ header
791 	 * and ECC bytes have been accounted for).
792 	 */
793 	cxt->pstore.bufsize = cxt->dprzs[0]->buffer_size;
794 	cxt->pstore.buf = kzalloc(cxt->pstore.bufsize, GFP_KERNEL);
795 	if (!cxt->pstore.buf) {
796 		pr_err("cannot allocate pstore crash dump buffer\n");
797 		err = -ENOMEM;
798 		goto fail_clear;
799 	}
800 
801 	cxt->pstore.flags = PSTORE_FLAGS_DMESG;
802 	if (cxt->console_size)
803 		cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE;
804 	if (cxt->ftrace_size)
805 		cxt->pstore.flags |= PSTORE_FLAGS_FTRACE;
806 	if (cxt->pmsg_size)
807 		cxt->pstore.flags |= PSTORE_FLAGS_PMSG;
808 
809 	err = pstore_register(&cxt->pstore);
810 	if (err) {
811 		pr_err("registering with pstore failed\n");
812 		goto fail_buf;
813 	}
814 
815 	/*
816 	 * Update the module parameter variables as well so they are visible
817 	 * through /sys/module/ramoops/parameters/
818 	 */
819 	mem_size = pdata->mem_size;
820 	mem_address = pdata->mem_address;
821 	record_size = pdata->record_size;
822 	dump_oops = pdata->dump_oops;
823 	ramoops_console_size = pdata->console_size;
824 	ramoops_pmsg_size = pdata->pmsg_size;
825 	ramoops_ftrace_size = pdata->ftrace_size;
826 
827 	pr_info("using 0x%lx@0x%llx, ecc: %d\n",
828 		cxt->size, (unsigned long long)cxt->phys_addr,
829 		cxt->ecc_info.ecc_size);
830 
831 	return 0;
832 
833 fail_buf:
834 	kfree(cxt->pstore.buf);
835 fail_clear:
836 	cxt->pstore.bufsize = 0;
837 	persistent_ram_free(cxt->mprz);
838 fail_init_mprz:
839 fail_init_fprz:
840 	persistent_ram_free(cxt->cprz);
841 fail_init_cprz:
842 	ramoops_free_przs(cxt);
843 fail_out:
844 	return err;
845 }
846 
847 static int ramoops_remove(struct platform_device *pdev)
848 {
849 	struct ramoops_context *cxt = &oops_cxt;
850 
851 	pstore_unregister(&cxt->pstore);
852 
853 	kfree(cxt->pstore.buf);
854 	cxt->pstore.bufsize = 0;
855 
856 	persistent_ram_free(cxt->mprz);
857 	persistent_ram_free(cxt->cprz);
858 	ramoops_free_przs(cxt);
859 
860 	return 0;
861 }
862 
863 static const struct of_device_id dt_match[] = {
864 	{ .compatible = "ramoops" },
865 	{}
866 };
867 
868 static struct platform_driver ramoops_driver = {
869 	.probe		= ramoops_probe,
870 	.remove		= ramoops_remove,
871 	.driver		= {
872 		.name		= "ramoops",
873 		.of_match_table	= dt_match,
874 	},
875 };
876 
877 static inline void ramoops_unregister_dummy(void)
878 {
879 	platform_device_unregister(dummy);
880 	dummy = NULL;
881 }
882 
883 static void __init ramoops_register_dummy(void)
884 {
885 	struct ramoops_platform_data pdata;
886 
887 	/*
888 	 * Prepare a dummy platform data structure to carry the module
889 	 * parameters. If mem_size isn't set, then there are no module
890 	 * parameters, and we can skip this.
891 	 */
892 	if (!mem_size)
893 		return;
894 
895 	pr_info("using module parameters\n");
896 
897 	memset(&pdata, 0, sizeof(pdata));
898 	pdata.mem_size = mem_size;
899 	pdata.mem_address = mem_address;
900 	pdata.mem_type = mem_type;
901 	pdata.record_size = record_size;
902 	pdata.console_size = ramoops_console_size;
903 	pdata.ftrace_size = ramoops_ftrace_size;
904 	pdata.pmsg_size = ramoops_pmsg_size;
905 	pdata.dump_oops = dump_oops;
906 	pdata.flags = RAMOOPS_FLAG_FTRACE_PER_CPU;
907 
908 	/*
909 	 * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
910 	 * (using 1 byte for ECC isn't much of use anyway).
911 	 */
912 	pdata.ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
913 
914 	dummy = platform_device_register_data(NULL, "ramoops", -1,
915 			&pdata, sizeof(pdata));
916 	if (IS_ERR(dummy)) {
917 		pr_info("could not create platform device: %ld\n",
918 			PTR_ERR(dummy));
919 		dummy = NULL;
920 		ramoops_unregister_dummy();
921 	}
922 }
923 
924 static int __init ramoops_init(void)
925 {
926 	int ret;
927 
928 	ramoops_register_dummy();
929 	ret = platform_driver_register(&ramoops_driver);
930 	if (ret != 0)
931 		ramoops_unregister_dummy();
932 
933 	return ret;
934 }
935 postcore_initcall(ramoops_init);
936 
937 static void __exit ramoops_exit(void)
938 {
939 	platform_driver_unregister(&ramoops_driver);
940 	ramoops_unregister_dummy();
941 }
942 module_exit(ramoops_exit);
943 
944 MODULE_LICENSE("GPL");
945 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
946 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");
947