1 // SPDX-License-Identifier: GPL-2.0-only
3  * Persistent Storage - platform driver interface parts.
5  * Copyright (C) 2007-2008 Google, Inc.
32  * We defer making "oops" entries appear in pstore - see
36 static int pstore_update_ms = -1;
39 		 "(default is -1, which means runtime updates are disabled; "
50 	"powerpc-ofw",
51 	"powerpc-common",
53 	"powerpc-opal",
77  * pstore no longer implements compression via the crypto API, and only
102  * Compression is only used for dmesg output, which consists of low-entropy
103  * ASCII text, and so we can assume worst-case 60%.
186 		return -EINVAL;  in pstore_compress()
189 				-MAX_WBITS, DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY);  in pstore_compress()
191 		return -EINVAL;  in pstore_compress()
195 		return -EINVAL;  in pstore_compress()
209 	/* Skip if not built-in or compression disabled. */  in allocate_buf_for_compression()
227 	compressed_size = (psinfo->bufsize * 100) / DMESG_COMP_PERCENT;  in allocate_buf_for_compression()
231 		       psinfo->bufsize, compress);  in allocate_buf_for_compression()
243 	/* A non-NULL big_oops_buf indicates compression is available. */  in allocate_buf_for_compression()
247 	pr_info("Using crash dump compression: %s\n", compress);  in allocate_buf_for_compression()
267 	record->psi = psinfo;  in pstore_record_init()
270 	record->time = ns_to_timespec64(ktime_get_real_fast_ns());  in pstore_record_init()
288 	why = kmsg_dump_reason_str(detail->reason);  in pstore_dump()
290 	if (pstore_cannot_block_path(detail->reason)) {  in pstore_dump()
291 		if (!raw_spin_trylock_irqsave(&psinfo->buf_lock, flags)) {  in pstore_dump()
292 			pr_err("dump skipped in %s path because of concurrent dump\n",  in pstore_dump()
297 		raw_spin_lock_irqsave(&psinfo->buf_lock, flags);  in pstore_dump()
307 		int zipped_len = -1;  in pstore_dump()
314 		record.reason = detail->reason;  in pstore_dump()
316 		record.buf = psinfo->buf;  in pstore_dump()
318 		dst = big_oops_buf ?: psinfo->buf;  in pstore_dump()
319 		dst_size = max_compressed_size ?: psinfo->bufsize;  in pstore_dump()
321 		/* Write dump header. */  in pstore_dump()
324 		dst_size -= header_size;  in pstore_dump()
326 		/* Write dump contents. */  in pstore_dump()
332 			zipped_len = pstore_compress(dst, psinfo->buf,  in pstore_dump()
334 						psinfo->bufsize);  in pstore_dump()
347 				record.size = psinfo->bufsize;  in pstore_dump()
348 				memcpy(psinfo->buf, dst, psinfo->bufsize);  in pstore_dump()
354 		ret = psinfo->write(&record);  in pstore_dump()
355 		if (ret == 0 && detail->reason == KMSG_DUMP_OOPS) {  in pstore_dump()
359 			/* Preserve only the first non-zero returned value. */  in pstore_dump()
367 	raw_spin_unlock_irqrestore(&psinfo->buf_lock, flags);  in pstore_dump()
370 		pr_err_once("backend (%s) writing error (%d)\n", psinfo->name,  in pstore_dump()
376 	.dump = pstore_dump,
405 	psinfo->write(&record);  in pstore_console_write()
410 	.index	= -1,
416 	strscpy(pstore_console.name, psinfo->name,  in pstore_register_console()
440 	if (record->buf)  in pstore_write_user_compat()
441 		return -EINVAL;  in pstore_write_user_compat()
443 	record->buf = vmemdup_user(buf, record->size);  in pstore_write_user_compat()
444 	if (IS_ERR(record->buf)) {  in pstore_write_user_compat()
445 		ret = PTR_ERR(record->buf);  in pstore_write_user_compat()
449 	ret = record->psi->write(record);  in pstore_write_user_compat()
451 	kvfree(record->buf);  in pstore_write_user_compat()
453 	record->buf = NULL;  in pstore_write_user_compat()
455 	return unlikely(ret < 0) ? ret : record->size;  in pstore_write_user_compat()
469 	if (backend && strcmp(backend, psi->name)) {  in pstore_register()
471 			backend, psi->name);  in pstore_register()
472 		return -EBUSY;  in pstore_register()
476 	if (!psi->flags) {  in pstore_register()
478 			psi->name);  in pstore_register()
479 		return -EINVAL;  in pstore_register()
483 	if (!psi->read || !psi->write) {  in pstore_register()
485 			psi->name);  in pstore_register()
486 		return -EINVAL;  in pstore_register()
489 	new_backend = kstrdup(psi->name, GFP_KERNEL);  in pstore_register()
491 		return -ENOMEM;  in pstore_register()
496 			psinfo->name, psi->name);  in pstore_register()
499 		return -EBUSY;  in pstore_register()
502 	if (!psi->write_user)  in pstore_register()
503 		psi->write_user = pstore_write_user_compat;  in pstore_register()
505 	mutex_init(&psinfo->read_mutex);  in pstore_register()
506 	raw_spin_lock_init(&psinfo->buf_lock);  in pstore_register()
508 	if (psi->flags & PSTORE_FLAGS_DMESG)  in pstore_register()
513 	if (psi->flags & PSTORE_FLAGS_DMESG) {  in pstore_register()
514 		pstore_dumper.max_reason = psinfo->max_reason;  in pstore_register()
517 	if (psi->flags & PSTORE_FLAGS_CONSOLE)  in pstore_register()
519 	if (psi->flags & PSTORE_FLAGS_FTRACE)  in pstore_register()
521 	if (psi->flags & PSTORE_FLAGS_PMSG)  in pstore_register()
533 	pr_info("Registered %s as persistent store backend\n", psi->name);  in pstore_register()
555 	if (psi->flags & PSTORE_FLAGS_PMSG)  in pstore_unregister()
557 	if (psi->flags & PSTORE_FLAGS_FTRACE)  in pstore_unregister()
559 	if (psi->flags & PSTORE_FLAGS_CONSOLE)  in pstore_unregister()
561 	if (psi->flags & PSTORE_FLAGS_DMESG)  in pstore_unregister()
577 	pr_info("Unregistered %s as persistent store backend\n", psi->name);  in pstore_unregister()
590 	if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !record->compressed)  in decompress_record()
594 	if (record->type != PSTORE_TYPE_DMESG) {  in decompress_record()
595 		pr_warn("ignored compressed record type %d\n", record->type);  in decompress_record()
600 	if (!zstream->workspace) {  in decompress_record()
601 		pr_warn("no decompression method initialized!\n");  in decompress_record()
612 	max_uncompressed_size = 3 * psinfo->bufsize;  in decompress_record()
613 	workspace = kvzalloc(max_uncompressed_size + record->ecc_notice_size,  in decompress_record()
618 	zstream->next_in	= record->buf;  in decompress_record()
619 	zstream->avail_in	= record->size;  in decompress_record()
620 	zstream->next_out	= workspace;  in decompress_record()
621 	zstream->avail_out	= max_uncompressed_size;  in decompress_record()
630 	unzipped_len = zstream->total_out;  in decompress_record()
633 	memcpy(workspace + unzipped_len, record->buf + record->size,  in decompress_record()
634 	       record->ecc_notice_size);  in decompress_record()
636 	/* Copy decompressed contents into an minimum-sized allocation. */  in decompress_record()
637 	unzipped = kvmemdup(workspace, unzipped_len + record->ecc_notice_size,  in decompress_record()
644 	kvfree(record->buf);  in decompress_record()
645 	record->buf = unzipped;  in decompress_record()
646 	record->size = unzipped_len;  in decompress_record()
647 	record->compressed = false;  in decompress_record()
652  * files in our filesystem.  Don't warn about -EEXIST errors
653  * when we are re-scanning the backing store looking to add new
669 		zlib_inflateInit2(&zstream, -DEF_WBITS);  in pstore_get_backend_records()
672 	mutex_lock(&psi->read_mutex);  in pstore_get_backend_records()
673 	if (psi->open && psi->open(psi))  in pstore_get_backend_records()
681 	for (; stop_loop; stop_loop--) {  in pstore_get_backend_records()
692 		record->size = psi->read(record);  in pstore_get_backend_records()
694 		/* No more records left in backend? */  in pstore_get_backend_records()
695 		if (record->size <= 0) {  in pstore_get_backend_records()
704 			kvfree(record->buf);  in pstore_get_backend_records()
705 			kfree(record->priv);  in pstore_get_backend_records()
707 			if (rc != -EEXIST || !quiet)  in pstore_get_backend_records()
711 	if (psi->close)  in pstore_get_backend_records()
712 		psi->close(psi);  in pstore_get_backend_records()
714 	mutex_unlock(&psi->read_mutex);  in pstore_get_backend_records()
724 			failed, psi->name);  in pstore_get_backend_records()
727 			psi->name);  in pstore_get_backend_records()
764 MODULE_DESCRIPTION("Persistent Storage - platform driver interface");