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 #include "internal.h"
25 
26 #define RAMOOPS_KERNMSG_HDR "===="
27 #define MIN_MEM_SIZE 4096UL
28 
29 static ulong record_size = MIN_MEM_SIZE;
30 module_param(record_size, ulong, 0400);
31 MODULE_PARM_DESC(record_size,
32 		"size of each dump done on oops/panic");
33 
34 static ulong ramoops_console_size = MIN_MEM_SIZE;
35 module_param_named(console_size, ramoops_console_size, ulong, 0400);
36 MODULE_PARM_DESC(console_size, "size of kernel console log");
37 
38 static ulong ramoops_ftrace_size = MIN_MEM_SIZE;
39 module_param_named(ftrace_size, ramoops_ftrace_size, ulong, 0400);
40 MODULE_PARM_DESC(ftrace_size, "size of ftrace log");
41 
42 static ulong ramoops_pmsg_size = MIN_MEM_SIZE;
43 module_param_named(pmsg_size, ramoops_pmsg_size, ulong, 0400);
44 MODULE_PARM_DESC(pmsg_size, "size of user space message log");
45 
46 static unsigned long long mem_address;
47 module_param_hw(mem_address, ullong, other, 0400);
48 MODULE_PARM_DESC(mem_address,
49 		"start of reserved RAM used to store oops/panic logs");
50 
51 static ulong mem_size;
52 module_param(mem_size, ulong, 0400);
53 MODULE_PARM_DESC(mem_size,
54 		"size of reserved RAM used to store oops/panic logs");
55 
56 static unsigned int mem_type;
57 module_param(mem_type, uint, 0400);
58 MODULE_PARM_DESC(mem_type,
59 		"memory type: 0=write-combined (default), 1=unbuffered, 2=cached");
60 
61 static int ramoops_max_reason = -1;
62 module_param_named(max_reason, ramoops_max_reason, int, 0400);
63 MODULE_PARM_DESC(max_reason,
64 		 "maximum reason for kmsg dump (default 2: Oops and Panic) ");
65 
66 static int ramoops_ecc;
67 module_param_named(ecc, ramoops_ecc, int, 0400);
68 MODULE_PARM_DESC(ramoops_ecc,
69 		"if non-zero, the option enables ECC support and specifies "
70 		"ECC buffer size in bytes (1 is a special value, means 16 "
71 		"bytes ECC)");
72 
73 static int ramoops_dump_oops = -1;
74 module_param_named(dump_oops, ramoops_dump_oops, int, 0400);
75 MODULE_PARM_DESC(dump_oops,
76 		 "(deprecated: use max_reason instead) set to 1 to dump oopses & panics, 0 to only dump panics");
77 
78 struct ramoops_context {
79 	struct persistent_ram_zone **dprzs;	/* Oops dump zones */
80 	struct persistent_ram_zone *cprz;	/* Console zone */
81 	struct persistent_ram_zone **fprzs;	/* Ftrace zones */
82 	struct persistent_ram_zone *mprz;	/* PMSG zone */
83 	phys_addr_t phys_addr;
84 	unsigned long size;
85 	unsigned int memtype;
86 	size_t record_size;
87 	size_t console_size;
88 	size_t ftrace_size;
89 	size_t pmsg_size;
90 	u32 flags;
91 	struct persistent_ram_ecc_info ecc_info;
92 	unsigned int max_dump_cnt;
93 	unsigned int dump_write_cnt;
94 	/* _read_cnt need clear on ramoops_pstore_open */
95 	unsigned int dump_read_cnt;
96 	unsigned int console_read_cnt;
97 	unsigned int max_ftrace_cnt;
98 	unsigned int ftrace_read_cnt;
99 	unsigned int pmsg_read_cnt;
100 	struct pstore_info pstore;
101 };
102 
103 static struct platform_device *dummy;
104 
ramoops_pstore_open(struct pstore_info * psi)105 static int ramoops_pstore_open(struct pstore_info *psi)
106 {
107 	struct ramoops_context *cxt = psi->data;
108 
109 	cxt->dump_read_cnt = 0;
110 	cxt->console_read_cnt = 0;
111 	cxt->ftrace_read_cnt = 0;
112 	cxt->pmsg_read_cnt = 0;
113 	return 0;
114 }
115 
116 static struct persistent_ram_zone *
ramoops_get_next_prz(struct persistent_ram_zone * przs[],int id,struct pstore_record * record)117 ramoops_get_next_prz(struct persistent_ram_zone *przs[], int id,
118 		     struct pstore_record *record)
119 {
120 	struct persistent_ram_zone *prz;
121 
122 	/* Give up if we never existed or have hit the end. */
123 	if (!przs)
124 		return NULL;
125 
126 	prz = przs[id];
127 	if (!prz)
128 		return NULL;
129 
130 	/* Update old/shadowed buffer. */
131 	if (prz->type == PSTORE_TYPE_DMESG)
132 		persistent_ram_save_old(prz);
133 
134 	if (!persistent_ram_old_size(prz))
135 		return NULL;
136 
137 	record->type = prz->type;
138 	record->id = id;
139 
140 	return prz;
141 }
142 
ramoops_read_kmsg_hdr(char * buffer,struct timespec64 * time,bool * compressed)143 static int ramoops_read_kmsg_hdr(char *buffer, struct timespec64 *time,
144 				  bool *compressed)
145 {
146 	char data_type;
147 	int header_length = 0;
148 
149 	if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lld.%lu-%c\n%n",
150 		   (time64_t *)&time->tv_sec, &time->tv_nsec, &data_type,
151 		   &header_length) == 3) {
152 		time->tv_nsec *= 1000;
153 		if (data_type == 'C')
154 			*compressed = true;
155 		else
156 			*compressed = false;
157 	} else if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lld.%lu\n%n",
158 			  (time64_t *)&time->tv_sec, &time->tv_nsec,
159 			  &header_length) == 2) {
160 		time->tv_nsec *= 1000;
161 		*compressed = false;
162 	} else {
163 		time->tv_sec = 0;
164 		time->tv_nsec = 0;
165 		*compressed = false;
166 	}
167 	return header_length;
168 }
169 
prz_ok(struct persistent_ram_zone * prz)170 static bool prz_ok(struct persistent_ram_zone *prz)
171 {
172 	return !!prz && !!(persistent_ram_old_size(prz) +
173 			   persistent_ram_ecc_string(prz, NULL, 0));
174 }
175 
ramoops_pstore_read(struct pstore_record * record)176 static ssize_t ramoops_pstore_read(struct pstore_record *record)
177 {
178 	ssize_t size = 0;
179 	struct ramoops_context *cxt = record->psi->data;
180 	struct persistent_ram_zone *prz = NULL;
181 	int header_length = 0;
182 	bool free_prz = false;
183 
184 	/*
185 	 * Ramoops headers provide time stamps for PSTORE_TYPE_DMESG, but
186 	 * PSTORE_TYPE_CONSOLE and PSTORE_TYPE_FTRACE don't currently have
187 	 * valid time stamps, so it is initialized to zero.
188 	 */
189 	record->time.tv_sec = 0;
190 	record->time.tv_nsec = 0;
191 	record->compressed = false;
192 
193 	/* Find the next valid persistent_ram_zone for DMESG */
194 	while (cxt->dump_read_cnt < cxt->max_dump_cnt && !prz) {
195 		prz = ramoops_get_next_prz(cxt->dprzs, cxt->dump_read_cnt++,
196 					   record);
197 		if (!prz_ok(prz))
198 			continue;
199 		header_length = ramoops_read_kmsg_hdr(persistent_ram_old(prz),
200 						      &record->time,
201 						      &record->compressed);
202 		/* Clear and skip this DMESG record if it has no valid header */
203 		if (!header_length) {
204 			persistent_ram_free_old(prz);
205 			persistent_ram_zap(prz);
206 			prz = NULL;
207 		}
208 	}
209 
210 	if (!prz_ok(prz) && !cxt->console_read_cnt++)
211 		prz = ramoops_get_next_prz(&cxt->cprz, 0 /* single */, record);
212 
213 	if (!prz_ok(prz) && !cxt->pmsg_read_cnt++)
214 		prz = ramoops_get_next_prz(&cxt->mprz, 0 /* single */, record);
215 
216 	/* ftrace is last since it may want to dynamically allocate memory. */
217 	if (!prz_ok(prz)) {
218 		if (!(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU) &&
219 		    !cxt->ftrace_read_cnt++) {
220 			prz = ramoops_get_next_prz(cxt->fprzs, 0 /* single */,
221 						   record);
222 		} else {
223 			/*
224 			 * Build a new dummy record which combines all the
225 			 * per-cpu records including metadata and ecc info.
226 			 */
227 			struct persistent_ram_zone *tmp_prz, *prz_next;
228 
229 			tmp_prz = kzalloc(sizeof(struct persistent_ram_zone),
230 					  GFP_KERNEL);
231 			if (!tmp_prz)
232 				return -ENOMEM;
233 			prz = tmp_prz;
234 			free_prz = true;
235 
236 			while (cxt->ftrace_read_cnt < cxt->max_ftrace_cnt) {
237 				prz_next = ramoops_get_next_prz(cxt->fprzs,
238 						cxt->ftrace_read_cnt++, record);
239 
240 				if (!prz_ok(prz_next))
241 					continue;
242 
243 				tmp_prz->ecc_info = prz_next->ecc_info;
244 				tmp_prz->corrected_bytes +=
245 						prz_next->corrected_bytes;
246 				tmp_prz->bad_blocks += prz_next->bad_blocks;
247 
248 				size = pstore_ftrace_combine_log(
249 						&tmp_prz->old_log,
250 						&tmp_prz->old_log_size,
251 						prz_next->old_log,
252 						prz_next->old_log_size);
253 				if (size)
254 					goto out;
255 			}
256 			record->id = 0;
257 		}
258 	}
259 
260 	if (!prz_ok(prz)) {
261 		size = 0;
262 		goto out;
263 	}
264 
265 	size = persistent_ram_old_size(prz) - header_length;
266 
267 	/* ECC correction notice */
268 	record->ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
269 
270 	record->buf = kmalloc(size + record->ecc_notice_size + 1, GFP_KERNEL);
271 	if (record->buf == NULL) {
272 		size = -ENOMEM;
273 		goto out;
274 	}
275 
276 	memcpy(record->buf, (char *)persistent_ram_old(prz) + header_length,
277 	       size);
278 
279 	persistent_ram_ecc_string(prz, record->buf + size,
280 				  record->ecc_notice_size + 1);
281 
282 out:
283 	if (free_prz) {
284 		kfree(prz->old_log);
285 		kfree(prz);
286 	}
287 
288 	return size;
289 }
290 
ramoops_write_kmsg_hdr(struct persistent_ram_zone * prz,struct pstore_record * record)291 static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz,
292 				     struct pstore_record *record)
293 {
294 	char hdr[36]; /* "===="(4), %lld(20), "."(1), %06lu(6), "-%c\n"(3) */
295 	size_t len;
296 
297 	len = scnprintf(hdr, sizeof(hdr),
298 		RAMOOPS_KERNMSG_HDR "%lld.%06lu-%c\n",
299 		(time64_t)record->time.tv_sec,
300 		record->time.tv_nsec / 1000,
301 		record->compressed ? 'C' : 'D');
302 	persistent_ram_write(prz, hdr, len);
303 
304 	return len;
305 }
306 
ramoops_pstore_write(struct pstore_record * record)307 static int notrace ramoops_pstore_write(struct pstore_record *record)
308 {
309 	struct ramoops_context *cxt = record->psi->data;
310 	struct persistent_ram_zone *prz;
311 	size_t size, hlen;
312 
313 	if (record->type == PSTORE_TYPE_CONSOLE) {
314 		if (!cxt->cprz)
315 			return -ENOMEM;
316 		persistent_ram_write(cxt->cprz, record->buf, record->size);
317 		return 0;
318 	} else if (record->type == PSTORE_TYPE_FTRACE) {
319 		int zonenum;
320 
321 		if (!cxt->fprzs)
322 			return -ENOMEM;
323 		/*
324 		 * Choose zone by if we're using per-cpu buffers.
325 		 */
326 		if (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
327 			zonenum = smp_processor_id();
328 		else
329 			zonenum = 0;
330 
331 		persistent_ram_write(cxt->fprzs[zonenum], record->buf,
332 				     record->size);
333 		return 0;
334 	} else if (record->type == PSTORE_TYPE_PMSG) {
335 		pr_warn_ratelimited("PMSG shouldn't call %s\n", __func__);
336 		return -EINVAL;
337 	}
338 
339 	if (record->type != PSTORE_TYPE_DMESG)
340 		return -EINVAL;
341 
342 	/*
343 	 * We could filter on record->reason here if we wanted to (which
344 	 * would duplicate what happened before the "max_reason" setting
345 	 * was added), but that would defeat the purpose of a system
346 	 * changing printk.always_kmsg_dump, so instead log everything that
347 	 * the kmsg dumper sends us, since it should be doing the filtering
348 	 * based on the combination of printk.always_kmsg_dump and our
349 	 * requested "max_reason".
350 	 */
351 
352 	/*
353 	 * Explicitly only take the first part of any new crash.
354 	 * If our buffer is larger than kmsg_bytes, this can never happen,
355 	 * and if our buffer is smaller than kmsg_bytes, we don't want the
356 	 * report split across multiple records.
357 	 */
358 	if (record->part != 1)
359 		return -ENOSPC;
360 
361 	if (!cxt->dprzs)
362 		return -ENOSPC;
363 
364 	prz = cxt->dprzs[cxt->dump_write_cnt];
365 
366 	/*
367 	 * Since this is a new crash dump, we need to reset the buffer in
368 	 * case it still has an old dump present. Without this, the new dump
369 	 * will get appended, which would seriously confuse anything trying
370 	 * to check dump file contents. Specifically, ramoops_read_kmsg_hdr()
371 	 * expects to find a dump header in the beginning of buffer data, so
372 	 * we must to reset the buffer values, in order to ensure that the
373 	 * header will be written to the beginning of the buffer.
374 	 */
375 	persistent_ram_zap(prz);
376 
377 	/* Build header and append record contents. */
378 	hlen = ramoops_write_kmsg_hdr(prz, record);
379 	if (!hlen)
380 		return -ENOMEM;
381 
382 	size = record->size;
383 	if (size + hlen > prz->buffer_size)
384 		size = prz->buffer_size - hlen;
385 	persistent_ram_write(prz, record->buf, size);
386 
387 	cxt->dump_write_cnt = (cxt->dump_write_cnt + 1) % cxt->max_dump_cnt;
388 
389 	return 0;
390 }
391 
ramoops_pstore_write_user(struct pstore_record * record,const char __user * buf)392 static int notrace ramoops_pstore_write_user(struct pstore_record *record,
393 					     const char __user *buf)
394 {
395 	if (record->type == PSTORE_TYPE_PMSG) {
396 		struct ramoops_context *cxt = record->psi->data;
397 
398 		if (!cxt->mprz)
399 			return -ENOMEM;
400 		return persistent_ram_write_user(cxt->mprz, buf, record->size);
401 	}
402 
403 	return -EINVAL;
404 }
405 
ramoops_pstore_erase(struct pstore_record * record)406 static int ramoops_pstore_erase(struct pstore_record *record)
407 {
408 	struct ramoops_context *cxt = record->psi->data;
409 	struct persistent_ram_zone *prz;
410 
411 	switch (record->type) {
412 	case PSTORE_TYPE_DMESG:
413 		if (record->id >= cxt->max_dump_cnt)
414 			return -EINVAL;
415 		prz = cxt->dprzs[record->id];
416 		break;
417 	case PSTORE_TYPE_CONSOLE:
418 		prz = cxt->cprz;
419 		break;
420 	case PSTORE_TYPE_FTRACE:
421 		if (record->id >= cxt->max_ftrace_cnt)
422 			return -EINVAL;
423 		prz = cxt->fprzs[record->id];
424 		break;
425 	case PSTORE_TYPE_PMSG:
426 		prz = cxt->mprz;
427 		break;
428 	default:
429 		return -EINVAL;
430 	}
431 
432 	persistent_ram_free_old(prz);
433 	persistent_ram_zap(prz);
434 
435 	return 0;
436 }
437 
438 static struct ramoops_context oops_cxt = {
439 	.pstore = {
440 		.owner	= THIS_MODULE,
441 		.name	= "ramoops",
442 		.open	= ramoops_pstore_open,
443 		.read	= ramoops_pstore_read,
444 		.write	= ramoops_pstore_write,
445 		.write_user	= ramoops_pstore_write_user,
446 		.erase	= ramoops_pstore_erase,
447 	},
448 };
449 
ramoops_free_przs(struct ramoops_context * cxt)450 static void ramoops_free_przs(struct ramoops_context *cxt)
451 {
452 	int i;
453 
454 	/* Free dump PRZs */
455 	if (cxt->dprzs) {
456 		for (i = 0; i < cxt->max_dump_cnt; i++)
457 			persistent_ram_free(cxt->dprzs[i]);
458 
459 		kfree(cxt->dprzs);
460 		cxt->max_dump_cnt = 0;
461 	}
462 
463 	/* Free ftrace PRZs */
464 	if (cxt->fprzs) {
465 		for (i = 0; i < cxt->max_ftrace_cnt; i++)
466 			persistent_ram_free(cxt->fprzs[i]);
467 		kfree(cxt->fprzs);
468 		cxt->max_ftrace_cnt = 0;
469 	}
470 }
471 
ramoops_init_przs(const char * name,struct device * dev,struct ramoops_context * cxt,struct persistent_ram_zone *** przs,phys_addr_t * paddr,size_t mem_sz,ssize_t record_size,unsigned int * cnt,u32 sig,u32 flags)472 static int ramoops_init_przs(const char *name,
473 			     struct device *dev, struct ramoops_context *cxt,
474 			     struct persistent_ram_zone ***przs,
475 			     phys_addr_t *paddr, size_t mem_sz,
476 			     ssize_t record_size,
477 			     unsigned int *cnt, u32 sig, u32 flags)
478 {
479 	int err = -ENOMEM;
480 	int i;
481 	size_t zone_sz;
482 	struct persistent_ram_zone **prz_ar;
483 
484 	/* Allocate nothing for 0 mem_sz or 0 record_size. */
485 	if (mem_sz == 0 || record_size == 0) {
486 		*cnt = 0;
487 		return 0;
488 	}
489 
490 	/*
491 	 * If we have a negative record size, calculate it based on
492 	 * mem_sz / *cnt. If we have a positive record size, calculate
493 	 * cnt from mem_sz / record_size.
494 	 */
495 	if (record_size < 0) {
496 		if (*cnt == 0)
497 			return 0;
498 		record_size = mem_sz / *cnt;
499 		if (record_size == 0) {
500 			dev_err(dev, "%s record size == 0 (%zu / %u)\n",
501 				name, mem_sz, *cnt);
502 			goto fail;
503 		}
504 	} else {
505 		*cnt = mem_sz / record_size;
506 		if (*cnt == 0) {
507 			dev_err(dev, "%s record count == 0 (%zu / %zu)\n",
508 				name, mem_sz, record_size);
509 			goto fail;
510 		}
511 	}
512 
513 	if (*paddr + mem_sz - cxt->phys_addr > cxt->size) {
514 		dev_err(dev, "no room for %s mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
515 			name,
516 			mem_sz, (unsigned long long)*paddr,
517 			cxt->size, (unsigned long long)cxt->phys_addr);
518 		goto fail;
519 	}
520 
521 	zone_sz = mem_sz / *cnt;
522 	if (!zone_sz) {
523 		dev_err(dev, "%s zone size == 0\n", name);
524 		goto fail;
525 	}
526 
527 	prz_ar = kcalloc(*cnt, sizeof(**przs), GFP_KERNEL);
528 	if (!prz_ar)
529 		goto fail;
530 
531 	for (i = 0; i < *cnt; i++) {
532 		char *label;
533 
534 		if (*cnt == 1)
535 			label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
536 		else
537 			label = kasprintf(GFP_KERNEL, "ramoops:%s(%d/%d)",
538 					  name, i, *cnt - 1);
539 		prz_ar[i] = persistent_ram_new(*paddr, zone_sz, sig,
540 					       &cxt->ecc_info,
541 					       cxt->memtype, flags, label);
542 		kfree(label);
543 		if (IS_ERR(prz_ar[i])) {
544 			err = PTR_ERR(prz_ar[i]);
545 			dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
546 				name, record_size,
547 				(unsigned long long)*paddr, err);
548 
549 			while (i > 0) {
550 				i--;
551 				persistent_ram_free(prz_ar[i]);
552 			}
553 			kfree(prz_ar);
554 			goto fail;
555 		}
556 		*paddr += zone_sz;
557 		prz_ar[i]->type = pstore_name_to_type(name);
558 	}
559 
560 	*przs = prz_ar;
561 	return 0;
562 
563 fail:
564 	*cnt = 0;
565 	return err;
566 }
567 
ramoops_init_prz(const char * name,struct device * dev,struct ramoops_context * cxt,struct persistent_ram_zone ** prz,phys_addr_t * paddr,size_t sz,u32 sig)568 static int ramoops_init_prz(const char *name,
569 			    struct device *dev, struct ramoops_context *cxt,
570 			    struct persistent_ram_zone **prz,
571 			    phys_addr_t *paddr, size_t sz, u32 sig)
572 {
573 	char *label;
574 
575 	if (!sz)
576 		return 0;
577 
578 	if (*paddr + sz - cxt->phys_addr > cxt->size) {
579 		dev_err(dev, "no room for %s mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
580 			name, sz, (unsigned long long)*paddr,
581 			cxt->size, (unsigned long long)cxt->phys_addr);
582 		return -ENOMEM;
583 	}
584 
585 	label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
586 	*prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info,
587 				  cxt->memtype, PRZ_FLAG_ZAP_OLD, label);
588 	kfree(label);
589 	if (IS_ERR(*prz)) {
590 		int err = PTR_ERR(*prz);
591 
592 		dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
593 			name, sz, (unsigned long long)*paddr, err);
594 		return err;
595 	}
596 
597 	*paddr += sz;
598 	(*prz)->type = pstore_name_to_type(name);
599 
600 	return 0;
601 }
602 
603 /* Read a u32 from a dt property and make sure it's safe for an int. */
ramoops_parse_dt_u32(struct platform_device * pdev,const char * propname,u32 default_value,u32 * value)604 static int ramoops_parse_dt_u32(struct platform_device *pdev,
605 				const char *propname,
606 				u32 default_value, u32 *value)
607 {
608 	u32 val32 = 0;
609 	int ret;
610 
611 	ret = of_property_read_u32(pdev->dev.of_node, propname, &val32);
612 	if (ret == -EINVAL) {
613 		/* field is missing, use default value. */
614 		val32 = default_value;
615 	} else if (ret < 0) {
616 		dev_err(&pdev->dev, "failed to parse property %s: %d\n",
617 			propname, ret);
618 		return ret;
619 	}
620 
621 	/* Sanity check our results. */
622 	if (val32 > INT_MAX) {
623 		dev_err(&pdev->dev, "%s %u > INT_MAX\n", propname, val32);
624 		return -EOVERFLOW;
625 	}
626 
627 	*value = val32;
628 	return 0;
629 }
630 
ramoops_parse_dt(struct platform_device * pdev,struct ramoops_platform_data * pdata)631 static int ramoops_parse_dt(struct platform_device *pdev,
632 			    struct ramoops_platform_data *pdata)
633 {
634 	struct device_node *of_node = pdev->dev.of_node;
635 	struct device_node *parent_node;
636 	struct resource *res;
637 	u32 value;
638 	int ret;
639 
640 	dev_dbg(&pdev->dev, "using Device Tree\n");
641 
642 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
643 	if (!res) {
644 		dev_err(&pdev->dev,
645 			"failed to locate DT /reserved-memory resource\n");
646 		return -EINVAL;
647 	}
648 
649 	pdata->mem_size = resource_size(res);
650 	pdata->mem_address = res->start;
651 	/*
652 	 * Setting "unbuffered" is deprecated and will be ignored if
653 	 * "mem_type" is also specified.
654 	 */
655 	pdata->mem_type = of_property_read_bool(of_node, "unbuffered");
656 	/*
657 	 * Setting "no-dump-oops" is deprecated and will be ignored if
658 	 * "max_reason" is also specified.
659 	 */
660 	if (of_property_read_bool(of_node, "no-dump-oops"))
661 		pdata->max_reason = KMSG_DUMP_PANIC;
662 	else
663 		pdata->max_reason = KMSG_DUMP_OOPS;
664 
665 #define parse_u32(name, field, default_value) {				\
666 		ret = ramoops_parse_dt_u32(pdev, name, default_value,	\
667 					    &value);			\
668 		if (ret < 0)						\
669 			return ret;					\
670 		field = value;						\
671 	}
672 
673 	parse_u32("mem-type", pdata->record_size, pdata->mem_type);
674 	parse_u32("record-size", pdata->record_size, 0);
675 	parse_u32("console-size", pdata->console_size, 0);
676 	parse_u32("ftrace-size", pdata->ftrace_size, 0);
677 	parse_u32("pmsg-size", pdata->pmsg_size, 0);
678 	parse_u32("ecc-size", pdata->ecc_info.ecc_size, 0);
679 	parse_u32("flags", pdata->flags, 0);
680 	parse_u32("max-reason", pdata->max_reason, pdata->max_reason);
681 
682 #undef parse_u32
683 
684 	/*
685 	 * Some old Chromebooks relied on the kernel setting the
686 	 * console_size and pmsg_size to the record size since that's
687 	 * what the downstream kernel did.  These same Chromebooks had
688 	 * "ramoops" straight under the root node which isn't
689 	 * according to the current upstream bindings (though it was
690 	 * arguably acceptable under a prior version of the bindings).
691 	 * Let's make those old Chromebooks work by detecting that
692 	 * we're not a child of "reserved-memory" and mimicking the
693 	 * expected behavior.
694 	 */
695 	parent_node = of_get_parent(of_node);
696 	if (!of_node_name_eq(parent_node, "reserved-memory") &&
697 	    !pdata->console_size && !pdata->ftrace_size &&
698 	    !pdata->pmsg_size && !pdata->ecc_info.ecc_size) {
699 		pdata->console_size = pdata->record_size;
700 		pdata->pmsg_size = pdata->record_size;
701 	}
702 	of_node_put(parent_node);
703 
704 	return 0;
705 }
706 
ramoops_probe(struct platform_device * pdev)707 static int ramoops_probe(struct platform_device *pdev)
708 {
709 	struct device *dev = &pdev->dev;
710 	struct ramoops_platform_data *pdata = dev->platform_data;
711 	struct ramoops_platform_data pdata_local;
712 	struct ramoops_context *cxt = &oops_cxt;
713 	size_t dump_mem_sz;
714 	phys_addr_t paddr;
715 	int err = -EINVAL;
716 
717 	/*
718 	 * Only a single ramoops area allowed at a time, so fail extra
719 	 * probes.
720 	 */
721 	if (cxt->max_dump_cnt) {
722 		pr_err("already initialized\n");
723 		goto fail_out;
724 	}
725 
726 	if (dev_of_node(dev) && !pdata) {
727 		pdata = &pdata_local;
728 		memset(pdata, 0, sizeof(*pdata));
729 
730 		err = ramoops_parse_dt(pdev, pdata);
731 		if (err < 0)
732 			goto fail_out;
733 	}
734 
735 	/* Make sure we didn't get bogus platform data pointer. */
736 	if (!pdata) {
737 		pr_err("NULL platform data\n");
738 		goto fail_out;
739 	}
740 
741 	if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size &&
742 			!pdata->ftrace_size && !pdata->pmsg_size)) {
743 		pr_err("The memory size and the record/console size must be "
744 			"non-zero\n");
745 		goto fail_out;
746 	}
747 
748 	if (pdata->record_size && !is_power_of_2(pdata->record_size))
749 		pdata->record_size = rounddown_pow_of_two(pdata->record_size);
750 	if (pdata->console_size && !is_power_of_2(pdata->console_size))
751 		pdata->console_size = rounddown_pow_of_two(pdata->console_size);
752 	if (pdata->ftrace_size && !is_power_of_2(pdata->ftrace_size))
753 		pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
754 	if (pdata->pmsg_size && !is_power_of_2(pdata->pmsg_size))
755 		pdata->pmsg_size = rounddown_pow_of_two(pdata->pmsg_size);
756 
757 	cxt->size = pdata->mem_size;
758 	cxt->phys_addr = pdata->mem_address;
759 	cxt->memtype = pdata->mem_type;
760 	cxt->record_size = pdata->record_size;
761 	cxt->console_size = pdata->console_size;
762 	cxt->ftrace_size = pdata->ftrace_size;
763 	cxt->pmsg_size = pdata->pmsg_size;
764 	cxt->flags = pdata->flags;
765 	cxt->ecc_info = pdata->ecc_info;
766 
767 	paddr = cxt->phys_addr;
768 
769 	dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size
770 			- cxt->pmsg_size;
771 	err = ramoops_init_przs("dmesg", dev, cxt, &cxt->dprzs, &paddr,
772 				dump_mem_sz, cxt->record_size,
773 				&cxt->max_dump_cnt, 0, 0);
774 	if (err)
775 		goto fail_out;
776 
777 	err = ramoops_init_prz("console", dev, cxt, &cxt->cprz, &paddr,
778 			       cxt->console_size, 0);
779 	if (err)
780 		goto fail_init_cprz;
781 
782 	cxt->max_ftrace_cnt = (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
783 				? nr_cpu_ids
784 				: 1;
785 	err = ramoops_init_przs("ftrace", dev, cxt, &cxt->fprzs, &paddr,
786 				cxt->ftrace_size, -1,
787 				&cxt->max_ftrace_cnt, LINUX_VERSION_CODE,
788 				(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
789 					? PRZ_FLAG_NO_LOCK : 0);
790 	if (err)
791 		goto fail_init_fprz;
792 
793 	err = ramoops_init_prz("pmsg", dev, cxt, &cxt->mprz, &paddr,
794 				cxt->pmsg_size, 0);
795 	if (err)
796 		goto fail_init_mprz;
797 
798 	cxt->pstore.data = cxt;
799 	/*
800 	 * Prepare frontend flags based on which areas are initialized.
801 	 * For ramoops_init_przs() cases, the "max count" variable tells
802 	 * if there are regions present. For ramoops_init_prz() cases,
803 	 * the single region size is how to check.
804 	 */
805 	cxt->pstore.flags = 0;
806 	if (cxt->max_dump_cnt) {
807 		cxt->pstore.flags |= PSTORE_FLAGS_DMESG;
808 		cxt->pstore.max_reason = pdata->max_reason;
809 	}
810 	if (cxt->console_size)
811 		cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE;
812 	if (cxt->max_ftrace_cnt)
813 		cxt->pstore.flags |= PSTORE_FLAGS_FTRACE;
814 	if (cxt->pmsg_size)
815 		cxt->pstore.flags |= PSTORE_FLAGS_PMSG;
816 
817 	/*
818 	 * Since bufsize is only used for dmesg crash dumps, it
819 	 * must match the size of the dprz record (after PRZ header
820 	 * and ECC bytes have been accounted for).
821 	 */
822 	if (cxt->pstore.flags & PSTORE_FLAGS_DMESG) {
823 		cxt->pstore.bufsize = cxt->dprzs[0]->buffer_size;
824 		cxt->pstore.buf = kzalloc(cxt->pstore.bufsize, GFP_KERNEL);
825 		if (!cxt->pstore.buf) {
826 			pr_err("cannot allocate pstore crash dump buffer\n");
827 			err = -ENOMEM;
828 			goto fail_clear;
829 		}
830 	}
831 
832 	err = pstore_register(&cxt->pstore);
833 	if (err) {
834 		pr_err("registering with pstore failed\n");
835 		goto fail_buf;
836 	}
837 
838 	/*
839 	 * Update the module parameter variables as well so they are visible
840 	 * through /sys/module/ramoops/parameters/
841 	 */
842 	mem_size = pdata->mem_size;
843 	mem_address = pdata->mem_address;
844 	record_size = pdata->record_size;
845 	ramoops_max_reason = pdata->max_reason;
846 	ramoops_console_size = pdata->console_size;
847 	ramoops_pmsg_size = pdata->pmsg_size;
848 	ramoops_ftrace_size = pdata->ftrace_size;
849 
850 	pr_info("using 0x%lx@0x%llx, ecc: %d\n",
851 		cxt->size, (unsigned long long)cxt->phys_addr,
852 		cxt->ecc_info.ecc_size);
853 
854 	return 0;
855 
856 fail_buf:
857 	kfree(cxt->pstore.buf);
858 fail_clear:
859 	cxt->pstore.bufsize = 0;
860 	persistent_ram_free(cxt->mprz);
861 fail_init_mprz:
862 fail_init_fprz:
863 	persistent_ram_free(cxt->cprz);
864 fail_init_cprz:
865 	ramoops_free_przs(cxt);
866 fail_out:
867 	return err;
868 }
869 
ramoops_remove(struct platform_device * pdev)870 static int ramoops_remove(struct platform_device *pdev)
871 {
872 	struct ramoops_context *cxt = &oops_cxt;
873 
874 	pstore_unregister(&cxt->pstore);
875 
876 	kfree(cxt->pstore.buf);
877 	cxt->pstore.bufsize = 0;
878 
879 	persistent_ram_free(cxt->mprz);
880 	persistent_ram_free(cxt->cprz);
881 	ramoops_free_przs(cxt);
882 
883 	return 0;
884 }
885 
886 static const struct of_device_id dt_match[] = {
887 	{ .compatible = "ramoops" },
888 	{}
889 };
890 
891 static struct platform_driver ramoops_driver = {
892 	.probe		= ramoops_probe,
893 	.remove		= ramoops_remove,
894 	.driver		= {
895 		.name		= "ramoops",
896 		.of_match_table	= dt_match,
897 	},
898 };
899 
ramoops_unregister_dummy(void)900 static inline void ramoops_unregister_dummy(void)
901 {
902 	platform_device_unregister(dummy);
903 	dummy = NULL;
904 }
905 
ramoops_register_dummy(void)906 static void __init ramoops_register_dummy(void)
907 {
908 	struct ramoops_platform_data pdata;
909 
910 	/*
911 	 * Prepare a dummy platform data structure to carry the module
912 	 * parameters. If mem_size isn't set, then there are no module
913 	 * parameters, and we can skip this.
914 	 */
915 	if (!mem_size)
916 		return;
917 
918 	pr_info("using module parameters\n");
919 
920 	memset(&pdata, 0, sizeof(pdata));
921 	pdata.mem_size = mem_size;
922 	pdata.mem_address = mem_address;
923 	pdata.mem_type = mem_type;
924 	pdata.record_size = record_size;
925 	pdata.console_size = ramoops_console_size;
926 	pdata.ftrace_size = ramoops_ftrace_size;
927 	pdata.pmsg_size = ramoops_pmsg_size;
928 	/* If "max_reason" is set, its value has priority over "dump_oops". */
929 	if (ramoops_max_reason >= 0)
930 		pdata.max_reason = ramoops_max_reason;
931 	/* Otherwise, if "dump_oops" is set, parse it into "max_reason". */
932 	else if (ramoops_dump_oops != -1)
933 		pdata.max_reason = ramoops_dump_oops ? KMSG_DUMP_OOPS
934 						     : KMSG_DUMP_PANIC;
935 	/* And if neither are explicitly set, use the default. */
936 	else
937 		pdata.max_reason = KMSG_DUMP_OOPS;
938 	pdata.flags = RAMOOPS_FLAG_FTRACE_PER_CPU;
939 
940 	/*
941 	 * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
942 	 * (using 1 byte for ECC isn't much of use anyway).
943 	 */
944 	pdata.ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
945 
946 	dummy = platform_device_register_data(NULL, "ramoops", -1,
947 			&pdata, sizeof(pdata));
948 	if (IS_ERR(dummy)) {
949 		pr_info("could not create platform device: %ld\n",
950 			PTR_ERR(dummy));
951 		dummy = NULL;
952 	}
953 }
954 
ramoops_init(void)955 static int __init ramoops_init(void)
956 {
957 	int ret;
958 
959 	ramoops_register_dummy();
960 	ret = platform_driver_register(&ramoops_driver);
961 	if (ret != 0)
962 		ramoops_unregister_dummy();
963 
964 	return ret;
965 }
966 postcore_initcall(ramoops_init);
967 
ramoops_exit(void)968 static void __exit ramoops_exit(void)
969 {
970 	platform_driver_unregister(&ramoops_driver);
971 	ramoops_unregister_dummy();
972 }
973 module_exit(ramoops_exit);
974 
975 MODULE_LICENSE("GPL");
976 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
977 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");
978