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()
289 	why = kmsg_dump_reason_str(detail->reason);  in pstore_dump()
291 	if (pstore_cannot_block_path(detail->reason)) {  in pstore_dump()
292 		if (!raw_spin_trylock_irqsave(&psinfo->buf_lock, flags)) {  in pstore_dump()
293 			pr_err("dump skipped in %s path because of concurrent dump\n",  in pstore_dump()
298 		raw_spin_lock_irqsave(&psinfo->buf_lock, flags);  in pstore_dump()
308 		int zipped_len = -1;  in pstore_dump()
315 		record.reason = detail->reason;  in pstore_dump()
317 		record.buf = psinfo->buf;  in pstore_dump()
319 		dst = big_oops_buf ?: psinfo->buf;  in pstore_dump()
320 		dst_size = max_compressed_size ?: psinfo->bufsize;  in pstore_dump()
322 		/* Write dump header. */  in pstore_dump()
325 		dst_size -= header_size;  in pstore_dump()
327 		/* Write dump contents. */  in pstore_dump()
333 			zipped_len = pstore_compress(dst, psinfo->buf,  in pstore_dump()
335 						psinfo->bufsize);  in pstore_dump()
348 				record.size = psinfo->bufsize;  in pstore_dump()
349 				memcpy(psinfo->buf, dst, psinfo->bufsize);  in pstore_dump()
355 		ret = psinfo->write(&record);  in pstore_dump()
356 		if (ret == 0 && detail->reason == KMSG_DUMP_OOPS) {  in pstore_dump()
360 			/* Preserve only the first non-zero returned value. */  in pstore_dump()
368 	raw_spin_unlock_irqrestore(&psinfo->buf_lock, flags);  in pstore_dump()
371 		pr_err_once("backend (%s) writing error (%d)\n", psinfo->name,  in pstore_dump()
377 	.dump = pstore_dump,
406 	psinfo->write(&record);  in pstore_console_write()
411 	.index	= -1,
417 	strscpy(pstore_console.name, psinfo->name,  in pstore_register_console()
441 	if (record->buf)  in pstore_write_user_compat()
442 		return -EINVAL;  in pstore_write_user_compat()
444 	record->buf = vmemdup_user(buf, record->size);  in pstore_write_user_compat()
445 	if (IS_ERR(record->buf)) {  in pstore_write_user_compat()
446 		ret = PTR_ERR(record->buf);  in pstore_write_user_compat()
450 	ret = record->psi->write(record);  in pstore_write_user_compat()
452 	kvfree(record->buf);  in pstore_write_user_compat()
454 	record->buf = NULL;  in pstore_write_user_compat()
456 	return unlikely(ret < 0) ? ret : record->size;  in pstore_write_user_compat()
470 	if (backend && strcmp(backend, psi->name)) {  in pstore_register()
472 			backend, psi->name);  in pstore_register()
473 		return -EBUSY;  in pstore_register()
477 	if (!psi->flags) {  in pstore_register()
479 			psi->name);  in pstore_register()
480 		return -EINVAL;  in pstore_register()
484 	if (!psi->read || !psi->write) {  in pstore_register()
486 			psi->name);  in pstore_register()
487 		return -EINVAL;  in pstore_register()
490 	new_backend = kstrdup(psi->name, GFP_KERNEL);  in pstore_register()
492 		return -ENOMEM;  in pstore_register()
497 			psinfo->name, psi->name);  in pstore_register()
500 		return -EBUSY;  in pstore_register()
503 	if (!psi->write_user)  in pstore_register()
504 		psi->write_user = pstore_write_user_compat;  in pstore_register()
506 	mutex_init(&psinfo->read_mutex);  in pstore_register()
507 	raw_spin_lock_init(&psinfo->buf_lock);  in pstore_register()
509 	if (psi->flags & PSTORE_FLAGS_DMESG)  in pstore_register()
514 	if (psi->flags & PSTORE_FLAGS_DMESG) {  in pstore_register()
515 		pstore_dumper.max_reason = psinfo->max_reason;  in pstore_register()
518 	if (psi->flags & PSTORE_FLAGS_CONSOLE)  in pstore_register()
520 	if (psi->flags & PSTORE_FLAGS_FTRACE)  in pstore_register()
522 	if (psi->flags & PSTORE_FLAGS_PMSG)  in pstore_register()
534 	pr_info("Registered %s as persistent store backend\n", psi->name);  in pstore_register()
556 	if (psi->flags & PSTORE_FLAGS_PMSG)  in pstore_unregister()
558 	if (psi->flags & PSTORE_FLAGS_FTRACE)  in pstore_unregister()
560 	if (psi->flags & PSTORE_FLAGS_CONSOLE)  in pstore_unregister()
562 	if (psi->flags & PSTORE_FLAGS_DMESG)  in pstore_unregister()
578 	pr_info("Unregistered %s as persistent store backend\n", psi->name);  in pstore_unregister()
591 	if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !record->compressed)  in decompress_record()
595 	if (record->type != PSTORE_TYPE_DMESG) {  in decompress_record()
596 		pr_warn("ignored compressed record type %d\n", record->type);  in decompress_record()
601 	if (!zstream->workspace) {  in decompress_record()
602 		pr_warn("no decompression method initialized!\n");  in decompress_record()
613 	max_uncompressed_size = 3 * psinfo->bufsize;  in decompress_record()
614 	workspace = kvzalloc(max_uncompressed_size + record->ecc_notice_size,  in decompress_record()
619 	zstream->next_in	= record->buf;  in decompress_record()
620 	zstream->avail_in	= record->size;  in decompress_record()
621 	zstream->next_out	= workspace;  in decompress_record()
622 	zstream->avail_out	= max_uncompressed_size;  in decompress_record()
631 	unzipped_len = zstream->total_out;  in decompress_record()
634 	memcpy(workspace + unzipped_len, record->buf + record->size,  in decompress_record()
635 	       record->ecc_notice_size);  in decompress_record()
637 	/* Copy decompressed contents into an minimum-sized allocation. */  in decompress_record()
638 	unzipped = kvmemdup(workspace, unzipped_len + record->ecc_notice_size,  in decompress_record()
645 	kvfree(record->buf);  in decompress_record()
646 	record->buf = unzipped;  in decompress_record()
647 	record->size = unzipped_len;  in decompress_record()
648 	record->compressed = false;  in decompress_record()
653  * files in our filesystem.  Don't warn about -EEXIST errors
654  * when we are re-scanning the backing store looking to add new
670 		zlib_inflateInit2(&zstream, -DEF_WBITS);  in pstore_get_backend_records()
673 	mutex_lock(&psi->read_mutex);  in pstore_get_backend_records()
674 	if (psi->open && psi->open(psi))  in pstore_get_backend_records()
682 	for (; stop_loop; stop_loop--) {  in pstore_get_backend_records()
693 		record->size = psi->read(record);  in pstore_get_backend_records()
695 		/* No more records left in backend? */  in pstore_get_backend_records()
696 		if (record->size <= 0) {  in pstore_get_backend_records()
705 			kvfree(record->buf);  in pstore_get_backend_records()
706 			kfree(record->priv);  in pstore_get_backend_records()
708 			if (rc != -EEXIST || !quiet)  in pstore_get_backend_records()
712 	if (psi->close)  in pstore_get_backend_records()
713 		psi->close(psi);  in pstore_get_backend_records()
715 	mutex_unlock(&psi->read_mutex);  in pstore_get_backend_records()
725 			failed, psi->name);  in pstore_get_backend_records()
728 			psi->name);  in pstore_get_backend_records()
765 MODULE_DESCRIPTION("Persistent Storage - platform driver interface");