xref: /linux/fs/pstore/ram.c (revision f3a8b6645dc2e60d11f20c1c23afd964ff4e55ae)
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 **przs;
89 	struct persistent_ram_zone *cprz;
90 	struct persistent_ram_zone *fprz;
91 	struct persistent_ram_zone *mprz;
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 	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 ftrace_read_cnt;
107 	unsigned int pmsg_read_cnt;
108 	struct pstore_info pstore;
109 };
110 
111 static struct platform_device *dummy;
112 static struct ramoops_platform_data *dummy_data;
113 
114 static int ramoops_pstore_open(struct pstore_info *psi)
115 {
116 	struct ramoops_context *cxt = psi->data;
117 
118 	cxt->dump_read_cnt = 0;
119 	cxt->console_read_cnt = 0;
120 	cxt->ftrace_read_cnt = 0;
121 	cxt->pmsg_read_cnt = 0;
122 	return 0;
123 }
124 
125 static struct persistent_ram_zone *
126 ramoops_get_next_prz(struct persistent_ram_zone *przs[], uint *c, uint max,
127 		     u64 *id,
128 		     enum pstore_type_id *typep, enum pstore_type_id type,
129 		     bool update)
130 {
131 	struct persistent_ram_zone *prz;
132 	int i = (*c)++;
133 
134 	if (i >= max)
135 		return NULL;
136 
137 	prz = przs[i];
138 	if (!prz)
139 		return NULL;
140 
141 	/* Update old/shadowed buffer. */
142 	if (update)
143 		persistent_ram_save_old(prz);
144 
145 	if (!persistent_ram_old_size(prz))
146 		return NULL;
147 
148 	*typep = type;
149 	*id = i;
150 
151 	return prz;
152 }
153 
154 static int ramoops_read_kmsg_hdr(char *buffer, struct timespec *time,
155 				  bool *compressed)
156 {
157 	char data_type;
158 	int header_length = 0;
159 
160 	if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lu.%lu-%c\n%n", &time->tv_sec,
161 			&time->tv_nsec, &data_type, &header_length) == 3) {
162 		if (data_type == 'C')
163 			*compressed = true;
164 		else
165 			*compressed = false;
166 	} else if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lu.%lu\n%n",
167 			&time->tv_sec, &time->tv_nsec, &header_length) == 2) {
168 			*compressed = false;
169 	} else {
170 		time->tv_sec = 0;
171 		time->tv_nsec = 0;
172 		*compressed = false;
173 	}
174 	return header_length;
175 }
176 
177 static bool prz_ok(struct persistent_ram_zone *prz)
178 {
179 	return !!prz && !!(persistent_ram_old_size(prz) +
180 			   persistent_ram_ecc_string(prz, NULL, 0));
181 }
182 
183 static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
184 				   int *count, struct timespec *time,
185 				   char **buf, bool *compressed,
186 				   ssize_t *ecc_notice_size,
187 				   struct pstore_info *psi)
188 {
189 	ssize_t size;
190 	struct ramoops_context *cxt = psi->data;
191 	struct persistent_ram_zone *prz = NULL;
192 	int header_length = 0;
193 
194 	/* Ramoops headers provide time stamps for PSTORE_TYPE_DMESG, but
195 	 * PSTORE_TYPE_CONSOLE and PSTORE_TYPE_FTRACE don't currently have
196 	 * valid time stamps, so it is initialized to zero.
197 	 */
198 	time->tv_sec = 0;
199 	time->tv_nsec = 0;
200 	*compressed = false;
201 
202 	/* Find the next valid persistent_ram_zone for DMESG */
203 	while (cxt->dump_read_cnt < cxt->max_dump_cnt && !prz) {
204 		prz = ramoops_get_next_prz(cxt->przs, &cxt->dump_read_cnt,
205 					   cxt->max_dump_cnt, id, type,
206 					   PSTORE_TYPE_DMESG, 1);
207 		if (!prz_ok(prz))
208 			continue;
209 		header_length = ramoops_read_kmsg_hdr(persistent_ram_old(prz),
210 						      time, compressed);
211 		/* Clear and skip this DMESG record if it has no valid header */
212 		if (!header_length) {
213 			persistent_ram_free_old(prz);
214 			persistent_ram_zap(prz);
215 			prz = NULL;
216 		}
217 	}
218 
219 	if (!prz_ok(prz))
220 		prz = ramoops_get_next_prz(&cxt->cprz, &cxt->console_read_cnt,
221 					   1, id, type, PSTORE_TYPE_CONSOLE, 0);
222 	if (!prz_ok(prz))
223 		prz = ramoops_get_next_prz(&cxt->fprz, &cxt->ftrace_read_cnt,
224 					   1, id, type, PSTORE_TYPE_FTRACE, 0);
225 	if (!prz_ok(prz))
226 		prz = ramoops_get_next_prz(&cxt->mprz, &cxt->pmsg_read_cnt,
227 					   1, id, type, PSTORE_TYPE_PMSG, 0);
228 	if (!prz_ok(prz))
229 		return 0;
230 
231 	size = persistent_ram_old_size(prz) - header_length;
232 
233 	/* ECC correction notice */
234 	*ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
235 
236 	*buf = kmalloc(size + *ecc_notice_size + 1, GFP_KERNEL);
237 	if (*buf == NULL)
238 		return -ENOMEM;
239 
240 	memcpy(*buf, (char *)persistent_ram_old(prz) + header_length, size);
241 	persistent_ram_ecc_string(prz, *buf + size, *ecc_notice_size + 1);
242 
243 	return size;
244 }
245 
246 static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz,
247 				     bool compressed)
248 {
249 	char *hdr;
250 	struct timespec timestamp;
251 	size_t len;
252 
253 	/* Report zeroed timestamp if called before timekeeping has resumed. */
254 	if (__getnstimeofday(&timestamp)) {
255 		timestamp.tv_sec = 0;
256 		timestamp.tv_nsec = 0;
257 	}
258 	hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu-%c\n",
259 		(long)timestamp.tv_sec, (long)(timestamp.tv_nsec / 1000),
260 		compressed ? 'C' : 'D');
261 	WARN_ON_ONCE(!hdr);
262 	len = hdr ? strlen(hdr) : 0;
263 	persistent_ram_write(prz, hdr, len);
264 	kfree(hdr);
265 
266 	return len;
267 }
268 
269 static int notrace ramoops_pstore_write_buf(enum pstore_type_id type,
270 					    enum kmsg_dump_reason reason,
271 					    u64 *id, unsigned int part,
272 					    const char *buf,
273 					    bool compressed, size_t size,
274 					    struct pstore_info *psi)
275 {
276 	struct ramoops_context *cxt = psi->data;
277 	struct persistent_ram_zone *prz;
278 	size_t hlen;
279 
280 	if (type == PSTORE_TYPE_CONSOLE) {
281 		if (!cxt->cprz)
282 			return -ENOMEM;
283 		persistent_ram_write(cxt->cprz, buf, size);
284 		return 0;
285 	} else if (type == PSTORE_TYPE_FTRACE) {
286 		if (!cxt->fprz)
287 			return -ENOMEM;
288 		persistent_ram_write(cxt->fprz, buf, size);
289 		return 0;
290 	} else if (type == PSTORE_TYPE_PMSG) {
291 		if (!cxt->mprz)
292 			return -ENOMEM;
293 		persistent_ram_write(cxt->mprz, buf, size);
294 		return 0;
295 	}
296 
297 	if (type != PSTORE_TYPE_DMESG)
298 		return -EINVAL;
299 
300 	/* Out of the various dmesg dump types, ramoops is currently designed
301 	 * to only store crash logs, rather than storing general kernel logs.
302 	 */
303 	if (reason != KMSG_DUMP_OOPS &&
304 	    reason != KMSG_DUMP_PANIC)
305 		return -EINVAL;
306 
307 	/* Skip Oopes when configured to do so. */
308 	if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
309 		return -EINVAL;
310 
311 	/* Explicitly only take the first part of any new crash.
312 	 * If our buffer is larger than kmsg_bytes, this can never happen,
313 	 * and if our buffer is smaller than kmsg_bytes, we don't want the
314 	 * report split across multiple records.
315 	 */
316 	if (part != 1)
317 		return -ENOSPC;
318 
319 	if (!cxt->przs)
320 		return -ENOSPC;
321 
322 	prz = cxt->przs[cxt->dump_write_cnt];
323 
324 	hlen = ramoops_write_kmsg_hdr(prz, compressed);
325 	if (size + hlen > prz->buffer_size)
326 		size = prz->buffer_size - hlen;
327 	persistent_ram_write(prz, buf, size);
328 
329 	cxt->dump_write_cnt = (cxt->dump_write_cnt + 1) % cxt->max_dump_cnt;
330 
331 	return 0;
332 }
333 
334 static int notrace ramoops_pstore_write_buf_user(enum pstore_type_id type,
335 						 enum kmsg_dump_reason reason,
336 						 u64 *id, unsigned int part,
337 						 const char __user *buf,
338 						 bool compressed, size_t size,
339 						 struct pstore_info *psi)
340 {
341 	if (type == PSTORE_TYPE_PMSG) {
342 		struct ramoops_context *cxt = psi->data;
343 
344 		if (!cxt->mprz)
345 			return -ENOMEM;
346 		return persistent_ram_write_user(cxt->mprz, buf, size);
347 	}
348 
349 	return -EINVAL;
350 }
351 
352 static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, int count,
353 				struct timespec time, struct pstore_info *psi)
354 {
355 	struct ramoops_context *cxt = psi->data;
356 	struct persistent_ram_zone *prz;
357 
358 	switch (type) {
359 	case PSTORE_TYPE_DMESG:
360 		if (id >= cxt->max_dump_cnt)
361 			return -EINVAL;
362 		prz = cxt->przs[id];
363 		break;
364 	case PSTORE_TYPE_CONSOLE:
365 		prz = cxt->cprz;
366 		break;
367 	case PSTORE_TYPE_FTRACE:
368 		prz = cxt->fprz;
369 		break;
370 	case PSTORE_TYPE_PMSG:
371 		prz = cxt->mprz;
372 		break;
373 	default:
374 		return -EINVAL;
375 	}
376 
377 	persistent_ram_free_old(prz);
378 	persistent_ram_zap(prz);
379 
380 	return 0;
381 }
382 
383 static struct ramoops_context oops_cxt = {
384 	.pstore = {
385 		.owner	= THIS_MODULE,
386 		.name	= "ramoops",
387 		.open	= ramoops_pstore_open,
388 		.read	= ramoops_pstore_read,
389 		.write_buf	= ramoops_pstore_write_buf,
390 		.write_buf_user	= ramoops_pstore_write_buf_user,
391 		.erase	= ramoops_pstore_erase,
392 	},
393 };
394 
395 static void ramoops_free_przs(struct ramoops_context *cxt)
396 {
397 	int i;
398 
399 	if (!cxt->przs)
400 		return;
401 
402 	for (i = 0; i < cxt->max_dump_cnt; i++)
403 		persistent_ram_free(cxt->przs[i]);
404 
405 	kfree(cxt->przs);
406 	cxt->max_dump_cnt = 0;
407 }
408 
409 static int ramoops_init_przs(struct device *dev, struct ramoops_context *cxt,
410 			     phys_addr_t *paddr, size_t dump_mem_sz)
411 {
412 	int err = -ENOMEM;
413 	int i;
414 
415 	if (!cxt->record_size)
416 		return 0;
417 
418 	if (*paddr + dump_mem_sz - cxt->phys_addr > cxt->size) {
419 		dev_err(dev, "no room for dumps\n");
420 		return -ENOMEM;
421 	}
422 
423 	cxt->max_dump_cnt = dump_mem_sz / cxt->record_size;
424 	if (!cxt->max_dump_cnt)
425 		return -ENOMEM;
426 
427 	cxt->przs = kzalloc(sizeof(*cxt->przs) * cxt->max_dump_cnt,
428 			     GFP_KERNEL);
429 	if (!cxt->przs) {
430 		dev_err(dev, "failed to initialize a prz array for dumps\n");
431 		goto fail_mem;
432 	}
433 
434 	for (i = 0; i < cxt->max_dump_cnt; i++) {
435 		cxt->przs[i] = persistent_ram_new(*paddr, cxt->record_size, 0,
436 						  &cxt->ecc_info,
437 						  cxt->memtype);
438 		if (IS_ERR(cxt->przs[i])) {
439 			err = PTR_ERR(cxt->przs[i]);
440 			dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
441 				cxt->record_size, (unsigned long long)*paddr, err);
442 
443 			while (i > 0) {
444 				i--;
445 				persistent_ram_free(cxt->przs[i]);
446 			}
447 			goto fail_prz;
448 		}
449 		*paddr += cxt->record_size;
450 	}
451 
452 	return 0;
453 fail_prz:
454 	kfree(cxt->przs);
455 fail_mem:
456 	cxt->max_dump_cnt = 0;
457 	return err;
458 }
459 
460 static int ramoops_init_prz(struct device *dev, struct ramoops_context *cxt,
461 			    struct persistent_ram_zone **prz,
462 			    phys_addr_t *paddr, size_t sz, u32 sig)
463 {
464 	if (!sz)
465 		return 0;
466 
467 	if (*paddr + sz - cxt->phys_addr > cxt->size) {
468 		dev_err(dev, "no room for mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
469 			sz, (unsigned long long)*paddr,
470 			cxt->size, (unsigned long long)cxt->phys_addr);
471 		return -ENOMEM;
472 	}
473 
474 	*prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info, cxt->memtype);
475 	if (IS_ERR(*prz)) {
476 		int err = PTR_ERR(*prz);
477 
478 		dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
479 			sz, (unsigned long long)*paddr, err);
480 		return err;
481 	}
482 
483 	persistent_ram_zap(*prz);
484 
485 	*paddr += sz;
486 
487 	return 0;
488 }
489 
490 static int ramoops_parse_dt_size(struct platform_device *pdev,
491 				 const char *propname, u32 *value)
492 {
493 	u32 val32 = 0;
494 	int ret;
495 
496 	ret = of_property_read_u32(pdev->dev.of_node, propname, &val32);
497 	if (ret < 0 && ret != -EINVAL) {
498 		dev_err(&pdev->dev, "failed to parse property %s: %d\n",
499 			propname, ret);
500 		return ret;
501 	}
502 
503 	if (val32 > INT_MAX) {
504 		dev_err(&pdev->dev, "%s %u > INT_MAX\n", propname, val32);
505 		return -EOVERFLOW;
506 	}
507 
508 	*value = val32;
509 	return 0;
510 }
511 
512 static int ramoops_parse_dt(struct platform_device *pdev,
513 			    struct ramoops_platform_data *pdata)
514 {
515 	struct device_node *of_node = pdev->dev.of_node;
516 	struct resource *res;
517 	u32 value;
518 	int ret;
519 
520 	dev_dbg(&pdev->dev, "using Device Tree\n");
521 
522 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
523 	if (!res) {
524 		dev_err(&pdev->dev,
525 			"failed to locate DT /reserved-memory resource\n");
526 		return -EINVAL;
527 	}
528 
529 	pdata->mem_size = resource_size(res);
530 	pdata->mem_address = res->start;
531 	pdata->mem_type = of_property_read_bool(of_node, "unbuffered");
532 	pdata->dump_oops = !of_property_read_bool(of_node, "no-dump-oops");
533 
534 #define parse_size(name, field) {					\
535 		ret = ramoops_parse_dt_size(pdev, name, &value);	\
536 		if (ret < 0)						\
537 			return ret;					\
538 		field = value;						\
539 	}
540 
541 	parse_size("record-size", pdata->record_size);
542 	parse_size("console-size", pdata->console_size);
543 	parse_size("ftrace-size", pdata->ftrace_size);
544 	parse_size("pmsg-size", pdata->pmsg_size);
545 	parse_size("ecc-size", pdata->ecc_info.ecc_size);
546 
547 #undef parse_size
548 
549 	return 0;
550 }
551 
552 static int ramoops_probe(struct platform_device *pdev)
553 {
554 	struct device *dev = &pdev->dev;
555 	struct ramoops_platform_data *pdata = dev->platform_data;
556 	struct ramoops_context *cxt = &oops_cxt;
557 	size_t dump_mem_sz;
558 	phys_addr_t paddr;
559 	int err = -EINVAL;
560 
561 	if (dev_of_node(dev) && !pdata) {
562 		pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
563 		if (!pdata) {
564 			err = -ENOMEM;
565 			goto fail_out;
566 		}
567 
568 		err = ramoops_parse_dt(pdev, pdata);
569 		if (err < 0)
570 			goto fail_out;
571 	}
572 
573 	/* Only a single ramoops area allowed at a time, so fail extra
574 	 * probes.
575 	 */
576 	if (cxt->max_dump_cnt)
577 		goto fail_out;
578 
579 	if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size &&
580 			!pdata->ftrace_size && !pdata->pmsg_size)) {
581 		pr_err("The memory size and the record/console size must be "
582 			"non-zero\n");
583 		goto fail_out;
584 	}
585 
586 	if (pdata->record_size && !is_power_of_2(pdata->record_size))
587 		pdata->record_size = rounddown_pow_of_two(pdata->record_size);
588 	if (pdata->console_size && !is_power_of_2(pdata->console_size))
589 		pdata->console_size = rounddown_pow_of_two(pdata->console_size);
590 	if (pdata->ftrace_size && !is_power_of_2(pdata->ftrace_size))
591 		pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
592 	if (pdata->pmsg_size && !is_power_of_2(pdata->pmsg_size))
593 		pdata->pmsg_size = rounddown_pow_of_two(pdata->pmsg_size);
594 
595 	cxt->size = pdata->mem_size;
596 	cxt->phys_addr = pdata->mem_address;
597 	cxt->memtype = pdata->mem_type;
598 	cxt->record_size = pdata->record_size;
599 	cxt->console_size = pdata->console_size;
600 	cxt->ftrace_size = pdata->ftrace_size;
601 	cxt->pmsg_size = pdata->pmsg_size;
602 	cxt->dump_oops = pdata->dump_oops;
603 	cxt->ecc_info = pdata->ecc_info;
604 
605 	paddr = cxt->phys_addr;
606 
607 	dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size
608 			- cxt->pmsg_size;
609 	err = ramoops_init_przs(dev, cxt, &paddr, dump_mem_sz);
610 	if (err)
611 		goto fail_out;
612 
613 	err = ramoops_init_prz(dev, cxt, &cxt->cprz, &paddr,
614 			       cxt->console_size, 0);
615 	if (err)
616 		goto fail_init_cprz;
617 
618 	err = ramoops_init_prz(dev, cxt, &cxt->fprz, &paddr, cxt->ftrace_size,
619 			       LINUX_VERSION_CODE);
620 	if (err)
621 		goto fail_init_fprz;
622 
623 	err = ramoops_init_prz(dev, cxt, &cxt->mprz, &paddr, cxt->pmsg_size, 0);
624 	if (err)
625 		goto fail_init_mprz;
626 
627 	cxt->pstore.data = cxt;
628 	/*
629 	 * Console can handle any buffer size, so prefer LOG_LINE_MAX. If we
630 	 * have to handle dumps, we must have at least record_size buffer. And
631 	 * for ftrace, bufsize is irrelevant (if bufsize is 0, buf will be
632 	 * ZERO_SIZE_PTR).
633 	 */
634 	if (cxt->console_size)
635 		cxt->pstore.bufsize = 1024; /* LOG_LINE_MAX */
636 	cxt->pstore.bufsize = max(cxt->record_size, cxt->pstore.bufsize);
637 	cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
638 	if (!cxt->pstore.buf) {
639 		pr_err("cannot allocate pstore buffer\n");
640 		err = -ENOMEM;
641 		goto fail_clear;
642 	}
643 	spin_lock_init(&cxt->pstore.buf_lock);
644 
645 	cxt->pstore.flags = PSTORE_FLAGS_DMESG;
646 	if (cxt->console_size)
647 		cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE;
648 	if (cxt->ftrace_size)
649 		cxt->pstore.flags |= PSTORE_FLAGS_FTRACE;
650 	if (cxt->pmsg_size)
651 		cxt->pstore.flags |= PSTORE_FLAGS_PMSG;
652 
653 	err = pstore_register(&cxt->pstore);
654 	if (err) {
655 		pr_err("registering with pstore failed\n");
656 		goto fail_buf;
657 	}
658 
659 	/*
660 	 * Update the module parameter variables as well so they are visible
661 	 * through /sys/module/ramoops/parameters/
662 	 */
663 	mem_size = pdata->mem_size;
664 	mem_address = pdata->mem_address;
665 	record_size = pdata->record_size;
666 	dump_oops = pdata->dump_oops;
667 	ramoops_console_size = pdata->console_size;
668 	ramoops_pmsg_size = pdata->pmsg_size;
669 	ramoops_ftrace_size = pdata->ftrace_size;
670 
671 	pr_info("attached 0x%lx@0x%llx, ecc: %d/%d\n",
672 		cxt->size, (unsigned long long)cxt->phys_addr,
673 		cxt->ecc_info.ecc_size, cxt->ecc_info.block_size);
674 
675 	return 0;
676 
677 fail_buf:
678 	kfree(cxt->pstore.buf);
679 fail_clear:
680 	cxt->pstore.bufsize = 0;
681 	persistent_ram_free(cxt->mprz);
682 fail_init_mprz:
683 	persistent_ram_free(cxt->fprz);
684 fail_init_fprz:
685 	persistent_ram_free(cxt->cprz);
686 fail_init_cprz:
687 	ramoops_free_przs(cxt);
688 fail_out:
689 	return err;
690 }
691 
692 static int ramoops_remove(struct platform_device *pdev)
693 {
694 	struct ramoops_context *cxt = &oops_cxt;
695 
696 	pstore_unregister(&cxt->pstore);
697 
698 	kfree(cxt->pstore.buf);
699 	cxt->pstore.bufsize = 0;
700 
701 	persistent_ram_free(cxt->mprz);
702 	persistent_ram_free(cxt->fprz);
703 	persistent_ram_free(cxt->cprz);
704 	ramoops_free_przs(cxt);
705 
706 	return 0;
707 }
708 
709 static const struct of_device_id dt_match[] = {
710 	{ .compatible = "ramoops" },
711 	{}
712 };
713 
714 static struct platform_driver ramoops_driver = {
715 	.probe		= ramoops_probe,
716 	.remove		= ramoops_remove,
717 	.driver		= {
718 		.name		= "ramoops",
719 		.of_match_table	= dt_match,
720 	},
721 };
722 
723 static void ramoops_register_dummy(void)
724 {
725 	if (!mem_size)
726 		return;
727 
728 	pr_info("using module parameters\n");
729 
730 	dummy_data = kzalloc(sizeof(*dummy_data), GFP_KERNEL);
731 	if (!dummy_data) {
732 		pr_info("could not allocate pdata\n");
733 		return;
734 	}
735 
736 	dummy_data->mem_size = mem_size;
737 	dummy_data->mem_address = mem_address;
738 	dummy_data->mem_type = mem_type;
739 	dummy_data->record_size = record_size;
740 	dummy_data->console_size = ramoops_console_size;
741 	dummy_data->ftrace_size = ramoops_ftrace_size;
742 	dummy_data->pmsg_size = ramoops_pmsg_size;
743 	dummy_data->dump_oops = dump_oops;
744 	/*
745 	 * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
746 	 * (using 1 byte for ECC isn't much of use anyway).
747 	 */
748 	dummy_data->ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
749 
750 	dummy = platform_device_register_data(NULL, "ramoops", -1,
751 			dummy_data, sizeof(struct ramoops_platform_data));
752 	if (IS_ERR(dummy)) {
753 		pr_info("could not create platform device: %ld\n",
754 			PTR_ERR(dummy));
755 	}
756 }
757 
758 static int __init ramoops_init(void)
759 {
760 	ramoops_register_dummy();
761 	return platform_driver_register(&ramoops_driver);
762 }
763 postcore_initcall(ramoops_init);
764 
765 static void __exit ramoops_exit(void)
766 {
767 	platform_driver_unregister(&ramoops_driver);
768 	platform_device_unregister(dummy);
769 	kfree(dummy_data);
770 }
771 module_exit(ramoops_exit);
772 
773 MODULE_LICENSE("GPL");
774 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
775 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");
776