Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
index 503086f..8f0369a 100644
--- a/fs/pstore/Kconfig
+++ b/fs/pstore/Kconfig
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 config PSTORE
 	tristate "Persistent store support"
 	select CRYPTO if PSTORE_COMPRESS
@@ -141,7 +142,6 @@
 	tristate "Log panic/oops to a RAM buffer"
 	depends on PSTORE
 	depends on HAS_IOMEM
-	depends on HAVE_MEMBLOCK
 	select REED_SOLOMON
 	select REED_SOLOMON_ENC8
 	select REED_SOLOMON_DEC8
diff --git a/fs/pstore/ftrace.c b/fs/pstore/ftrace.c
index 06aab07..bfbfc26 100644
--- a/fs/pstore/ftrace.c
+++ b/fs/pstore/ftrace.c
@@ -1,14 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright 2012  Google, Inc.
- *
- * This software is licensed under the terms of the GNU General Public
- * License version 2, as published by the Free Software Foundation, and
- * may be copied, distributed, and modified under those terms.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
  */
 
 #include <linux/kernel.h>
@@ -120,27 +112,13 @@
 
 void pstore_register_ftrace(void)
 {
-	struct dentry *file;
-
 	if (!psinfo->write)
 		return;
 
 	pstore_ftrace_dir = debugfs_create_dir("pstore", NULL);
-	if (!pstore_ftrace_dir) {
-		pr_err("%s: unable to create pstore directory\n", __func__);
-		return;
-	}
 
-	file = debugfs_create_file("record_ftrace", 0600, pstore_ftrace_dir,
-				   NULL, &pstore_knob_fops);
-	if (!file) {
-		pr_err("%s: unable to create record_ftrace file\n", __func__);
-		goto err_file;
-	}
-
-	return;
-err_file:
-	debugfs_remove(pstore_ftrace_dir);
+	debugfs_create_file("record_ftrace", 0600, pstore_ftrace_dir, NULL,
+			    &pstore_knob_fops);
 }
 
 void pstore_unregister_ftrace(void)
@@ -148,7 +126,7 @@
 	mutex_lock(&pstore_ftrace_lock);
 	if (pstore_ftrace_enabled) {
 		unregister_ftrace_function(&pstore_ftrace_ops);
-		pstore_ftrace_enabled = 0;
+		pstore_ftrace_enabled = false;
 	}
 	mutex_unlock(&pstore_ftrace_lock);
 
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index 5fcb845..7fbe8f0 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -1,20 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Persistent Storage - ramfs parts.
  *
  * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
- *
- *  This program is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License version 2 as
- *  published by the Free Software Foundation.
- *
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
- *
- *  You should have received a copy of the GNU General Public License
- *  along with this program; if not, write to the Free Software
- *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
 #include <linux/module.h>
@@ -115,7 +103,7 @@
 
 	rec = (struct pstore_ftrace_record *)(ps->record->buf + data->off);
 
-	seq_printf(s, "CPU:%d ts:%llu %08lx  %08lx  %pf <- %pF\n",
+	seq_printf(s, "CPU:%d ts:%llu %08lx  %08lx  %ps <- %pS\n",
 		   pstore_ftrace_decode_cpu(rec),
 		   pstore_ftrace_read_timestamp(rec),
 		   rec->ip, rec->parent_ip, (void *)rec->ip,
@@ -330,65 +318,21 @@
 		goto fail;
 	inode->i_mode = S_IFREG | 0444;
 	inode->i_fop = &pstore_file_operations;
+	scnprintf(name, sizeof(name), "%s-%s-%llu%s",
+			pstore_type_to_name(record->type),
+			record->psi->name, record->id,
+			record->compressed ? ".enc.z" : "");
+
 	private = kzalloc(sizeof(*private), GFP_KERNEL);
 	if (!private)
-		goto fail_alloc;
-	private->record = record;
-
-	switch (record->type) {
-	case PSTORE_TYPE_DMESG:
-		scnprintf(name, sizeof(name), "dmesg-%s-%llu%s",
-			  record->psi->name, record->id,
-			  record->compressed ? ".enc.z" : "");
-		break;
-	case PSTORE_TYPE_CONSOLE:
-		scnprintf(name, sizeof(name), "console-%s-%llu",
-			  record->psi->name, record->id);
-		break;
-	case PSTORE_TYPE_FTRACE:
-		scnprintf(name, sizeof(name), "ftrace-%s-%llu",
-			  record->psi->name, record->id);
-		break;
-	case PSTORE_TYPE_MCE:
-		scnprintf(name, sizeof(name), "mce-%s-%llu",
-			  record->psi->name, record->id);
-		break;
-	case PSTORE_TYPE_PPC_RTAS:
-		scnprintf(name, sizeof(name), "rtas-%s-%llu",
-			  record->psi->name, record->id);
-		break;
-	case PSTORE_TYPE_PPC_OF:
-		scnprintf(name, sizeof(name), "powerpc-ofw-%s-%llu",
-			  record->psi->name, record->id);
-		break;
-	case PSTORE_TYPE_PPC_COMMON:
-		scnprintf(name, sizeof(name), "powerpc-common-%s-%llu",
-			  record->psi->name, record->id);
-		break;
-	case PSTORE_TYPE_PMSG:
-		scnprintf(name, sizeof(name), "pmsg-%s-%llu",
-			  record->psi->name, record->id);
-		break;
-	case PSTORE_TYPE_PPC_OPAL:
-		scnprintf(name, sizeof(name), "powerpc-opal-%s-%llu",
-			  record->psi->name, record->id);
-		break;
-	case PSTORE_TYPE_UNKNOWN:
-		scnprintf(name, sizeof(name), "unknown-%s-%llu",
-			  record->psi->name, record->id);
-		break;
-	default:
-		scnprintf(name, sizeof(name), "type%d-%s-%llu",
-			  record->type, record->psi->name, record->id);
-		break;
-	}
+		goto fail_inode;
 
 	dentry = d_alloc_name(root, name);
 	if (!dentry)
 		goto fail_private;
 
+	private->record = record;
 	inode->i_size = private->total_size = size;
-
 	inode->i_private = private;
 
 	if (record->time.tv_sec)
@@ -404,7 +348,7 @@
 
 fail_private:
 	free_pstore_private(private);
-fail_alloc:
+fail_inode:
 	iput(inode);
 
 fail:
@@ -482,12 +426,10 @@
 	.kill_sb	= pstore_kill_sb,
 };
 
-static int __init init_pstore_fs(void)
+int __init pstore_init_fs(void)
 {
 	int err;
 
-	pstore_choose_compression();
-
 	/* Create a convenient mount point for people to access pstore */
 	err = sysfs_create_mount_point(fs_kobj, "pstore");
 	if (err)
@@ -500,14 +442,9 @@
 out:
 	return err;
 }
-module_init(init_pstore_fs)
 
-static void __exit exit_pstore_fs(void)
+void __exit pstore_exit_fs(void)
 {
 	unregister_filesystem(&pstore_fs_type);
 	sysfs_remove_mount_point(fs_kobj, "pstore");
 }
-module_exit(exit_pstore_fs)
-
-MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
-MODULE_LICENSE("GPL");
diff --git a/fs/pstore/internal.h b/fs/pstore/internal.h
index fb767e2..7062ea4 100644
--- a/fs/pstore/internal.h
+++ b/fs/pstore/internal.h
@@ -37,7 +37,8 @@
 extern void	pstore_record_init(struct pstore_record *record,
 				   struct pstore_info *psi);
 
-/* Called during module_init() */
-extern void __init pstore_choose_compression(void);
+/* Called during pstore init/exit. */
+int __init	pstore_init_fs(void);
+void __exit	pstore_exit_fs(void);
 
 #endif
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 15e99d5..3d70246 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -1,21 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Persistent Storage - platform driver interface parts.
  *
  * Copyright (C) 2007-2008 Google, Inc.
  * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
- *
- *  This program is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License version 2 as
- *  published by the Free Software Foundation.
- *
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
- *
- *  You should have received a copy of the GNU General Public License
- *  along with this program; if not, write to the Free Software
- *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
 #define pr_fmt(fmt) "pstore: " fmt
@@ -59,6 +47,19 @@
 		 "enabling this option is not safe, it may lead to further "
 		 "corruption on Oopses)");
 
+/* Names should be in the same order as the enum pstore_type_id */
+static const char * const pstore_type_names[] = {
+	"dmesg",
+	"mce",
+	"console",
+	"ftrace",
+	"rtas",
+	"powerpc-ofw",
+	"powerpc-common",
+	"pmsg",
+	"powerpc-opal",
+};
+
 static int pstore_new_entry;
 
 static void pstore_timefunc(struct timer_list *);
@@ -104,6 +105,30 @@
 /* Tag each group of saved records with a sequence number */
 static int	oopscount;
 
+const char *pstore_type_to_name(enum pstore_type_id type)
+{
+	BUILD_BUG_ON(ARRAY_SIZE(pstore_type_names) != PSTORE_TYPE_MAX);
+
+	if (WARN_ON_ONCE(type >= PSTORE_TYPE_MAX))
+		return "unknown";
+
+	return pstore_type_names[type];
+}
+EXPORT_SYMBOL_GPL(pstore_type_to_name);
+
+enum pstore_type_id pstore_name_to_type(const char *name)
+{
+	int i;
+
+	for (i = 0; i < PSTORE_TYPE_MAX; i++) {
+		if (!strcmp(pstore_type_names[i], name))
+			return i;
+	}
+
+	return PSTORE_TYPE_MAX;
+}
+EXPORT_SYMBOL_GPL(pstore_name_to_type);
+
 static const char *get_reason_str(enum kmsg_dump_reason reason)
 {
 	switch (reason) {
@@ -124,26 +149,27 @@
 	}
 }
 
-bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
+/*
+ * Should pstore_dump() wait for a concurrent pstore_dump()? If
+ * not, the current pstore_dump() will report a failure to dump
+ * and return.
+ */
+static bool pstore_cannot_wait(enum kmsg_dump_reason reason)
 {
-	/*
-	 * In case of NMI path, pstore shouldn't be blocked
-	 * regardless of reason.
-	 */
+	/* In NMI path, pstore shouldn't block regardless of reason. */
 	if (in_nmi())
 		return true;
 
 	switch (reason) {
 	/* In panic case, other cpus are stopped by smp_send_stop(). */
 	case KMSG_DUMP_PANIC:
-	/* Emergency restart shouldn't be blocked by spin lock. */
+	/* Emergency restart shouldn't be blocked. */
 	case KMSG_DUMP_EMERG:
 		return true;
 	default:
 		return false;
 	}
 }
-EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
 
 #if IS_ENABLED(CONFIG_PSTORE_DEFLATE_COMPRESS)
 static int zbufsize_deflate(size_t size)
@@ -258,53 +284,61 @@
 	return outlen;
 }
 
-static int pstore_decompress(void *in, void *out,
-			     unsigned int inlen, unsigned int outlen)
-{
-	int ret;
-
-	ret = crypto_comp_decompress(tfm, in, inlen, out, &outlen);
-	if (ret) {
-		pr_err("crypto_comp_decompress failed, ret = %d!\n", ret);
-		return ret;
-	}
-
-	return outlen;
-}
-
 static void allocate_buf_for_compression(void)
 {
+	struct crypto_comp *ctx;
+	int size;
+	char *buf;
+
+	/* Skip if not built-in or compression backend not selected yet. */
 	if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !zbackend)
 		return;
 
+	/* Skip if no pstore backend yet or compression init already done. */
+	if (!psinfo || tfm)
+		return;
+
 	if (!crypto_has_comp(zbackend->name, 0, 0)) {
-		pr_err("No %s compression\n", zbackend->name);
+		pr_err("Unknown compression: %s\n", zbackend->name);
 		return;
 	}
 
-	big_oops_buf_sz = zbackend->zbufsize(psinfo->bufsize);
-	if (big_oops_buf_sz <= 0)
-		return;
-
-	big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
-	if (!big_oops_buf) {
-		pr_err("allocate compression buffer error!\n");
+	size = zbackend->zbufsize(psinfo->bufsize);
+	if (size <= 0) {
+		pr_err("Invalid compression size for %s: %d\n",
+		       zbackend->name, size);
 		return;
 	}
 
-	tfm = crypto_alloc_comp(zbackend->name, 0, 0);
-	if (IS_ERR_OR_NULL(tfm)) {
-		kfree(big_oops_buf);
-		big_oops_buf = NULL;
-		pr_err("crypto_alloc_comp() failed!\n");
+	buf = kmalloc(size, GFP_KERNEL);
+	if (!buf) {
+		pr_err("Failed %d byte compression buffer allocation for: %s\n",
+		       size, zbackend->name);
 		return;
 	}
+
+	ctx = crypto_alloc_comp(zbackend->name, 0, 0);
+	if (IS_ERR_OR_NULL(ctx)) {
+		kfree(buf);
+		pr_err("crypto_alloc_comp('%s') failed: %ld\n", zbackend->name,
+		       PTR_ERR(ctx));
+		return;
+	}
+
+	/* A non-NULL big_oops_buf indicates compression is available. */
+	tfm = ctx;
+	big_oops_buf_sz = size;
+	big_oops_buf = buf;
+
+	pr_info("Using crash dump compression: %s\n", zbackend->name);
 }
 
 static void free_buf_for_compression(void)
 {
-	if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && !IS_ERR_OR_NULL(tfm))
+	if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && tfm) {
 		crypto_free_comp(tfm);
+		tfm = NULL;
+	}
 	kfree(big_oops_buf);
 	big_oops_buf = NULL;
 	big_oops_buf_sz = 0;
@@ -348,9 +382,8 @@
 }
 
 /*
- * callback from kmsg_dump. (s2,l2) has the most recently
- * written bytes, older bytes are in (s1,l1). Save as much
- * as we can from the end of the buffer.
+ * callback from kmsg_dump. Save as much as we can (up to kmsg_bytes) from the
+ * end of the buffer.
  */
 static void pstore_dump(struct kmsg_dumper *dumper,
 			enum kmsg_dump_reason reason)
@@ -358,23 +391,23 @@
 	unsigned long	total = 0;
 	const char	*why;
 	unsigned int	part = 1;
-	unsigned long	flags = 0;
-	int		is_locked;
 	int		ret;
 
 	why = get_reason_str(reason);
 
-	if (pstore_cannot_block_path(reason)) {
-		is_locked = spin_trylock_irqsave(&psinfo->buf_lock, flags);
-		if (!is_locked) {
-			pr_err("pstore dump routine blocked in %s path, may corrupt error record\n"
-				       , in_nmi() ? "NMI" : why);
+	if (down_trylock(&psinfo->buf_lock)) {
+		/* Failed to acquire lock: give up if we cannot wait. */
+		if (pstore_cannot_wait(reason)) {
+			pr_err("dump skipped in %s path: may corrupt error record\n",
+				in_nmi() ? "NMI" : why);
 			return;
 		}
-	} else {
-		spin_lock_irqsave(&psinfo->buf_lock, flags);
-		is_locked = 1;
+		if (down_interruptible(&psinfo->buf_lock)) {
+			pr_err("could not grab semaphore?!\n");
+			return;
+		}
 	}
+
 	oopscount++;
 	while (total < kmsg_bytes) {
 		char *dst;
@@ -391,7 +424,7 @@
 		record.part = part;
 		record.buf = psinfo->buf;
 
-		if (big_oops_buf && is_locked) {
+		if (big_oops_buf) {
 			dst = big_oops_buf;
 			dst_size = big_oops_buf_sz;
 		} else {
@@ -409,7 +442,7 @@
 					  dst_size, &dump_size))
 			break;
 
-		if (big_oops_buf && is_locked) {
+		if (big_oops_buf) {
 			zipped_len = pstore_compress(dst, psinfo->buf,
 						header_size + dump_size,
 						psinfo->bufsize);
@@ -432,8 +465,8 @@
 		total += record.size;
 		part++;
 	}
-	if (is_locked)
-		spin_unlock_irqrestore(&psinfo->buf_lock, flags);
+
+	up(&psinfo->buf_lock);
 }
 
 static struct kmsg_dumper pstore_dumper = {
@@ -456,31 +489,17 @@
 #ifdef CONFIG_PSTORE_CONSOLE
 static void pstore_console_write(struct console *con, const char *s, unsigned c)
 {
-	const char *e = s + c;
+	struct pstore_record record;
 
-	while (s < e) {
-		struct pstore_record record;
-		unsigned long flags;
+	if (!c)
+		return;
 
-		pstore_record_init(&record, psinfo);
-		record.type = PSTORE_TYPE_CONSOLE;
+	pstore_record_init(&record, psinfo);
+	record.type = PSTORE_TYPE_CONSOLE;
 
-		if (c > psinfo->bufsize)
-			c = psinfo->bufsize;
-
-		if (oops_in_progress) {
-			if (!spin_trylock_irqsave(&psinfo->buf_lock, flags))
-				break;
-		} else {
-			spin_lock_irqsave(&psinfo->buf_lock, flags);
-		}
-		record.buf = (char *)s;
-		record.size = c;
-		psinfo->write(&record);
-		spin_unlock_irqrestore(&psinfo->buf_lock, flags);
-		s += c;
-		c = e - s;
-	}
+	record.buf = (char *)s;
+	record.size = c;
+	psinfo->write(&record);
 }
 
 static struct console pstore_console = {
@@ -569,6 +588,7 @@
 		psi->write_user = pstore_write_user_compat;
 	psinfo = psi;
 	mutex_init(&psinfo->read_mutex);
+	sema_init(&psinfo->buf_lock, 1);
 	spin_unlock(&pstore_lock);
 
 	if (owner && !try_module_get(owner)) {
@@ -576,7 +596,8 @@
 		return -EINVAL;
 	}
 
-	allocate_buf_for_compression();
+	if (psi->flags & PSTORE_FLAGS_DMESG)
+		allocate_buf_for_compression();
 
 	if (pstore_is_mounted())
 		pstore_get_records(0);
@@ -636,8 +657,9 @@
 
 static void decompress_record(struct pstore_record *record)
 {
+	int ret;
 	int unzipped_len;
-	char *decompressed;
+	char *unzipped, *workspace;
 
 	if (!record->compressed)
 		return;
@@ -648,35 +670,42 @@
 		return;
 	}
 
-	/* No compression method has created the common buffer. */
+	/* Missing compression buffer means compression was not initialized. */
 	if (!big_oops_buf) {
-		pr_warn("no decompression buffer allocated\n");
+		pr_warn("no decompression method initialized!\n");
 		return;
 	}
 
-	unzipped_len = pstore_decompress(record->buf, big_oops_buf,
-					 record->size, big_oops_buf_sz);
-	if (unzipped_len <= 0) {
-		pr_err("decompression failed: %d\n", unzipped_len);
+	/* Allocate enough space to hold max decompression and ECC. */
+	unzipped_len = big_oops_buf_sz;
+	workspace = kmalloc(unzipped_len + record->ecc_notice_size,
+			    GFP_KERNEL);
+	if (!workspace)
 		return;
-	}
 
-	/* Build new buffer for decompressed contents. */
-	decompressed = kmalloc(unzipped_len + record->ecc_notice_size,
-			       GFP_KERNEL);
-	if (!decompressed) {
-		pr_err("decompression ran out of memory\n");
+	/* After decompression "unzipped_len" is almost certainly smaller. */
+	ret = crypto_comp_decompress(tfm, record->buf, record->size,
+					  workspace, &unzipped_len);
+	if (ret) {
+		pr_err("crypto_comp_decompress failed, ret = %d!\n", ret);
+		kfree(workspace);
 		return;
 	}
-	memcpy(decompressed, big_oops_buf, unzipped_len);
 
 	/* Append ECC notice to decompressed buffer. */
-	memcpy(decompressed + unzipped_len, record->buf + record->size,
+	memcpy(workspace + unzipped_len, record->buf + record->size,
 	       record->ecc_notice_size);
 
-	/* Swap out compresed contents with decompressed contents. */
+	/* Copy decompressed contents into an minimum-sized allocation. */
+	unzipped = kmemdup(workspace, unzipped_len + record->ecc_notice_size,
+			   GFP_KERNEL);
+	kfree(workspace);
+	if (!unzipped)
+		return;
+
+	/* Swap out compressed contents with decompressed contents. */
 	kfree(record->buf);
-	record->buf = decompressed;
+	record->buf = unzipped;
 	record->size = unzipped_len;
 	record->compressed = false;
 }
@@ -774,14 +803,43 @@
 	for (step = zbackends; step->name; step++) {
 		if (!strcmp(compress, step->name)) {
 			zbackend = step;
-			pr_info("using %s compression\n", zbackend->name);
 			return;
 		}
 	}
 }
 
+static int __init pstore_init(void)
+{
+	int ret;
+
+	pstore_choose_compression();
+
+	/*
+	 * Check if any pstore backends registered earlier but did not
+	 * initialize compression because crypto was not ready. If so,
+	 * initialize compression now.
+	 */
+	allocate_buf_for_compression();
+
+	ret = pstore_init_fs();
+	if (ret)
+		return ret;
+
+	return 0;
+}
+late_initcall(pstore_init);
+
+static void __exit pstore_exit(void)
+{
+	pstore_exit_fs();
+}
+module_exit(pstore_exit)
+
 module_param(compress, charp, 0444);
 MODULE_PARM_DESC(compress, "Pstore compression to use");
 
 module_param(backend, charp, 0444);
 MODULE_PARM_DESC(backend, "Pstore backend to use");
+
+MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
+MODULE_LICENSE("GPL");
diff --git a/fs/pstore/pmsg.c b/fs/pstore/pmsg.c
index 24db02d..d8542ec 100644
--- a/fs/pstore/pmsg.c
+++ b/fs/pstore/pmsg.c
@@ -1,14 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright 2014  Google, Inc.
- *
- * This software is licensed under the terms of the GNU General Public
- * License version 2, as published by the Free Software Foundation, and
- * may be copied, distributed, and modified under those terms.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
  */
 
 #include <linux/cdev.h>
@@ -33,7 +25,7 @@
 	record.size = count;
 
 	/* check outside lock, page in any data. write_user also checks */
-	if (!access_ok(VERIFY_READ, buf, count))
+	if (!access_ok(buf, count))
 		return -EFAULT;
 
 	mutex_lock(&pmsg_lock);
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 03cd593..8caff83 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -1,23 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * RAM Oops/Panic logger
  *
  * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
  * Copyright (C) 2011 Kees Cook <keescook@chromium.org>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * version 2 as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
- * 02110-1301 USA
- *
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
@@ -110,7 +96,6 @@
 };
 
 static struct platform_device *dummy;
-static struct ramoops_platform_data *dummy_data;
 
 static int ramoops_pstore_open(struct pstore_info *psi)
 {
@@ -124,31 +109,28 @@
 }
 
 static struct persistent_ram_zone *
-ramoops_get_next_prz(struct persistent_ram_zone *przs[], uint *c, uint max,
-		     u64 *id,
-		     enum pstore_type_id *typep, enum pstore_type_id type,
-		     bool update)
+ramoops_get_next_prz(struct persistent_ram_zone *przs[], int id,
+		     struct pstore_record *record)
 {
 	struct persistent_ram_zone *prz;
-	int i = (*c)++;
 
 	/* Give up if we never existed or have hit the end. */
-	if (!przs || i >= max)
+	if (!przs)
 		return NULL;
 
-	prz = przs[i];
+	prz = przs[id];
 	if (!prz)
 		return NULL;
 
 	/* Update old/shadowed buffer. */
-	if (update)
+	if (prz->type == PSTORE_TYPE_DMESG)
 		persistent_ram_save_old(prz);
 
 	if (!persistent_ram_old_size(prz))
 		return NULL;
 
-	*typep = type;
-	*id = i;
+	record->type = prz->type;
+	record->id = id;
 
 	return prz;
 }
@@ -162,6 +144,7 @@
 	if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lld.%lu-%c\n%n",
 		   (time64_t *)&time->tv_sec, &time->tv_nsec, &data_type,
 		   &header_length) == 3) {
+		time->tv_nsec *= 1000;
 		if (data_type == 'C')
 			*compressed = true;
 		else
@@ -169,6 +152,7 @@
 	} else if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lld.%lu\n%n",
 			  (time64_t *)&time->tv_sec, &time->tv_nsec,
 			  &header_length) == 2) {
+		time->tv_nsec *= 1000;
 		*compressed = false;
 	} else {
 		time->tv_sec = 0;
@@ -255,10 +239,8 @@
 
 	/* Find the next valid persistent_ram_zone for DMESG */
 	while (cxt->dump_read_cnt < cxt->max_dump_cnt && !prz) {
-		prz = ramoops_get_next_prz(cxt->dprzs, &cxt->dump_read_cnt,
-					   cxt->max_dump_cnt, &record->id,
-					   &record->type,
-					   PSTORE_TYPE_DMESG, 1);
+		prz = ramoops_get_next_prz(cxt->dprzs, cxt->dump_read_cnt++,
+					   record);
 		if (!prz_ok(prz))
 			continue;
 		header_length = ramoops_read_kmsg_hdr(persistent_ram_old(prz),
@@ -272,22 +254,18 @@
 		}
 	}
 
-	if (!prz_ok(prz))
-		prz = ramoops_get_next_prz(&cxt->cprz, &cxt->console_read_cnt,
-					   1, &record->id, &record->type,
-					   PSTORE_TYPE_CONSOLE, 0);
+	if (!prz_ok(prz) && !cxt->console_read_cnt++)
+		prz = ramoops_get_next_prz(&cxt->cprz, 0 /* single */, record);
 
-	if (!prz_ok(prz))
-		prz = ramoops_get_next_prz(&cxt->mprz, &cxt->pmsg_read_cnt,
-					   1, &record->id, &record->type,
-					   PSTORE_TYPE_PMSG, 0);
+	if (!prz_ok(prz) && !cxt->pmsg_read_cnt++)
+		prz = ramoops_get_next_prz(&cxt->mprz, 0 /* single */, record);
 
 	/* ftrace is last since it may want to dynamically allocate memory. */
 	if (!prz_ok(prz)) {
-		if (!(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)) {
-			prz = ramoops_get_next_prz(cxt->fprzs,
-					&cxt->ftrace_read_cnt, 1, &record->id,
-					&record->type, PSTORE_TYPE_FTRACE, 0);
+		if (!(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU) &&
+		    !cxt->ftrace_read_cnt++) {
+			prz = ramoops_get_next_prz(cxt->fprzs, 0 /* single */,
+						   record);
 		} else {
 			/*
 			 * Build a new dummy record which combines all the
@@ -299,15 +277,12 @@
 					  GFP_KERNEL);
 			if (!tmp_prz)
 				return -ENOMEM;
+			prz = tmp_prz;
 			free_prz = true;
 
 			while (cxt->ftrace_read_cnt < cxt->max_ftrace_cnt) {
 				prz_next = ramoops_get_next_prz(cxt->fprzs,
-						&cxt->ftrace_read_cnt,
-						cxt->max_ftrace_cnt,
-						&record->id,
-						&record->type,
-						PSTORE_TYPE_FTRACE, 0);
+						cxt->ftrace_read_cnt++, record);
 
 				if (!prz_ok(prz_next))
 					continue;
@@ -321,7 +296,6 @@
 					goto out;
 			}
 			record->id = 0;
-			prz = tmp_prz;
 		}
 	}
 
@@ -359,17 +333,15 @@
 static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz,
 				     struct pstore_record *record)
 {
-	char *hdr;
+	char hdr[36]; /* "===="(4), %lld(20), "."(1), %06lu(6), "-%c\n"(3) */
 	size_t len;
 
-	hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lld.%06lu-%c\n",
+	len = scnprintf(hdr, sizeof(hdr),
+		RAMOOPS_KERNMSG_HDR "%lld.%06lu-%c\n",
 		(time64_t)record->time.tv_sec,
 		record->time.tv_nsec / 1000,
 		record->compressed ? 'C' : 'D');
-	WARN_ON_ONCE(!hdr);
-	len = hdr ? strlen(hdr) : 0;
 	persistent_ram_write(prz, hdr, len);
-	kfree(hdr);
 
 	return len;
 }
@@ -437,6 +409,9 @@
 
 	/* Build header and append record contents. */
 	hlen = ramoops_write_kmsg_hdr(prz, record);
+	if (!hlen)
+		return -ENOMEM;
+
 	size = record->size;
 	if (size + hlen > prz->buffer_size)
 		size = prz->buffer_size - hlen;
@@ -587,9 +562,16 @@
 		goto fail;
 
 	for (i = 0; i < *cnt; i++) {
+		char *label;
+
+		if (*cnt == 1)
+			label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
+		else
+			label = kasprintf(GFP_KERNEL, "ramoops:%s(%d/%d)",
+					  name, i, *cnt - 1);
 		prz_ar[i] = persistent_ram_new(*paddr, zone_sz, sig,
-						  &cxt->ecc_info,
-						  cxt->memtype, flags);
+					       &cxt->ecc_info,
+					       cxt->memtype, flags, label);
 		if (IS_ERR(prz_ar[i])) {
 			err = PTR_ERR(prz_ar[i]);
 			dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
@@ -604,6 +586,7 @@
 			goto fail;
 		}
 		*paddr += zone_sz;
+		prz_ar[i]->type = pstore_name_to_type(name);
 	}
 
 	*przs = prz_ar;
@@ -619,6 +602,8 @@
 			    struct persistent_ram_zone **prz,
 			    phys_addr_t *paddr, size_t sz, u32 sig)
 {
+	char *label;
+
 	if (!sz)
 		return 0;
 
@@ -629,8 +614,9 @@
 		return -ENOMEM;
 	}
 
+	label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
 	*prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info,
-				  cxt->memtype, 0);
+				  cxt->memtype, PRZ_FLAG_ZAP_OLD, label);
 	if (IS_ERR(*prz)) {
 		int err = PTR_ERR(*prz);
 
@@ -639,9 +625,8 @@
 		return err;
 	}
 
-	persistent_ram_zap(*prz);
-
 	*paddr += sz;
+	(*prz)->type = pstore_name_to_type(name);
 
 	return 0;
 }
@@ -672,6 +657,7 @@
 			    struct ramoops_platform_data *pdata)
 {
 	struct device_node *of_node = pdev->dev.of_node;
+	struct device_node *parent_node;
 	struct resource *res;
 	u32 value;
 	int ret;
@@ -706,6 +692,26 @@
 
 #undef parse_size
 
+	/*
+	 * Some old Chromebooks relied on the kernel setting the
+	 * console_size and pmsg_size to the record size since that's
+	 * what the downstream kernel did.  These same Chromebooks had
+	 * "ramoops" straight under the root node which isn't
+	 * according to the current upstream bindings (though it was
+	 * arguably acceptable under a prior version of the bindings).
+	 * Let's make those old Chromebooks work by detecting that
+	 * we're not a child of "reserved-memory" and mimicking the
+	 * expected behavior.
+	 */
+	parent_node = of_get_parent(of_node);
+	if (!of_node_name_eq(parent_node, "reserved-memory") &&
+	    !pdata->console_size && !pdata->ftrace_size &&
+	    !pdata->pmsg_size && !pdata->ecc_info.ecc_size) {
+		pdata->console_size = pdata->record_size;
+		pdata->pmsg_size = pdata->record_size;
+	}
+	of_node_put(parent_node);
+
 	return 0;
 }
 
@@ -713,24 +719,12 @@
 {
 	struct device *dev = &pdev->dev;
 	struct ramoops_platform_data *pdata = dev->platform_data;
+	struct ramoops_platform_data pdata_local;
 	struct ramoops_context *cxt = &oops_cxt;
 	size_t dump_mem_sz;
 	phys_addr_t paddr;
 	int err = -EINVAL;
 
-	if (dev_of_node(dev) && !pdata) {
-		pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
-		if (!pdata) {
-			pr_err("cannot allocate platform data buffer\n");
-			err = -ENOMEM;
-			goto fail_out;
-		}
-
-		err = ramoops_parse_dt(pdev, pdata);
-		if (err < 0)
-			goto fail_out;
-	}
-
 	/*
 	 * Only a single ramoops area allowed at a time, so fail extra
 	 * probes.
@@ -740,6 +734,15 @@
 		goto fail_out;
 	}
 
+	if (dev_of_node(dev) && !pdata) {
+		pdata = &pdata_local;
+		memset(pdata, 0, sizeof(*pdata));
+
+		err = ramoops_parse_dt(pdev, pdata);
+		if (err < 0)
+			goto fail_out;
+	}
+
 	/* Make sure we didn't get bogus platform data pointer. */
 	if (!pdata) {
 		pr_err("NULL platform data\n");
@@ -777,7 +780,7 @@
 
 	dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size
 			- cxt->pmsg_size;
-	err = ramoops_init_przs("dump", dev, cxt, &cxt->dprzs, &paddr,
+	err = ramoops_init_przs("dmesg", dev, cxt, &cxt->dprzs, &paddr,
 				dump_mem_sz, cxt->record_size,
 				&cxt->max_dump_cnt, 0, 0);
 	if (err)
@@ -806,26 +809,35 @@
 
 	cxt->pstore.data = cxt;
 	/*
+	 * Prepare frontend flags based on which areas are initialized.
+	 * For ramoops_init_przs() cases, the "max count" variable tells
+	 * if there are regions present. For ramoops_init_prz() cases,
+	 * the single region size is how to check.
+	 */
+	cxt->pstore.flags = 0;
+	if (cxt->max_dump_cnt)
+		cxt->pstore.flags |= PSTORE_FLAGS_DMESG;
+	if (cxt->console_size)
+		cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE;
+	if (cxt->max_ftrace_cnt)
+		cxt->pstore.flags |= PSTORE_FLAGS_FTRACE;
+	if (cxt->pmsg_size)
+		cxt->pstore.flags |= PSTORE_FLAGS_PMSG;
+
+	/*
 	 * Since bufsize is only used for dmesg crash dumps, it
 	 * must match the size of the dprz record (after PRZ header
 	 * and ECC bytes have been accounted for).
 	 */
-	cxt->pstore.bufsize = cxt->dprzs[0]->buffer_size;
-	cxt->pstore.buf = kzalloc(cxt->pstore.bufsize, GFP_KERNEL);
-	if (!cxt->pstore.buf) {
-		pr_err("cannot allocate pstore crash dump buffer\n");
-		err = -ENOMEM;
-		goto fail_clear;
+	if (cxt->pstore.flags & PSTORE_FLAGS_DMESG) {
+		cxt->pstore.bufsize = cxt->dprzs[0]->buffer_size;
+		cxt->pstore.buf = kzalloc(cxt->pstore.bufsize, GFP_KERNEL);
+		if (!cxt->pstore.buf) {
+			pr_err("cannot allocate pstore crash dump buffer\n");
+			err = -ENOMEM;
+			goto fail_clear;
+		}
 	}
-	spin_lock_init(&cxt->pstore.buf_lock);
-
-	cxt->pstore.flags = PSTORE_FLAGS_DMESG;
-	if (cxt->console_size)
-		cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE;
-	if (cxt->ftrace_size)
-		cxt->pstore.flags |= PSTORE_FLAGS_FTRACE;
-	if (cxt->pmsg_size)
-		cxt->pstore.flags |= PSTORE_FLAGS_PMSG;
 
 	err = pstore_register(&cxt->pstore);
 	if (err) {
@@ -845,9 +857,9 @@
 	ramoops_pmsg_size = pdata->pmsg_size;
 	ramoops_ftrace_size = pdata->ftrace_size;
 
-	pr_info("attached 0x%lx@0x%llx, ecc: %d/%d\n",
+	pr_info("using 0x%lx@0x%llx, ecc: %d\n",
 		cxt->size, (unsigned long long)cxt->phys_addr,
-		cxt->ecc_info.ecc_size, cxt->ecc_info.block_size);
+		cxt->ecc_info.ecc_size);
 
 	return 0;
 
@@ -899,13 +911,12 @@
 {
 	platform_device_unregister(dummy);
 	dummy = NULL;
-
-	kfree(dummy_data);
-	dummy_data = NULL;
 }
 
 static void __init ramoops_register_dummy(void)
 {
+	struct ramoops_platform_data pdata;
+
 	/*
 	 * Prepare a dummy platform data structure to carry the module
 	 * parameters. If mem_size isn't set, then there are no module
@@ -916,30 +927,25 @@
 
 	pr_info("using module parameters\n");
 
-	dummy_data = kzalloc(sizeof(*dummy_data), GFP_KERNEL);
-	if (!dummy_data) {
-		pr_info("could not allocate pdata\n");
-		return;
-	}
-
-	dummy_data->mem_size = mem_size;
-	dummy_data->mem_address = mem_address;
-	dummy_data->mem_type = mem_type;
-	dummy_data->record_size = record_size;
-	dummy_data->console_size = ramoops_console_size;
-	dummy_data->ftrace_size = ramoops_ftrace_size;
-	dummy_data->pmsg_size = ramoops_pmsg_size;
-	dummy_data->dump_oops = dump_oops;
-	dummy_data->flags = RAMOOPS_FLAG_FTRACE_PER_CPU;
+	memset(&pdata, 0, sizeof(pdata));
+	pdata.mem_size = mem_size;
+	pdata.mem_address = mem_address;
+	pdata.mem_type = mem_type;
+	pdata.record_size = record_size;
+	pdata.console_size = ramoops_console_size;
+	pdata.ftrace_size = ramoops_ftrace_size;
+	pdata.pmsg_size = ramoops_pmsg_size;
+	pdata.dump_oops = dump_oops;
+	pdata.flags = RAMOOPS_FLAG_FTRACE_PER_CPU;
 
 	/*
 	 * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
 	 * (using 1 byte for ECC isn't much of use anyway).
 	 */
-	dummy_data->ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
+	pdata.ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
 
 	dummy = platform_device_register_data(NULL, "ramoops", -1,
-			dummy_data, sizeof(struct ramoops_platform_data));
+			&pdata, sizeof(pdata));
 	if (IS_ERR(dummy)) {
 		pr_info("could not create platform device: %ld\n",
 			PTR_ERR(dummy));
@@ -959,7 +965,7 @@
 
 	return ret;
 }
-late_initcall(ramoops_init);
+postcore_initcall(ramoops_init);
 
 static void __exit ramoops_exit(void)
 {
diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
index 0792595..8823f65 100644
--- a/fs/pstore/ram_core.c
+++ b/fs/pstore/ram_core.c
@@ -1,18 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2012 Google, Inc.
- *
- * This software is licensed under the terms of the GNU General Public
- * License version 2, as published by the Free Software Foundation, and
- * may be copied, distributed, and modified under those terms.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
  */
 
-#define pr_fmt(fmt) "persistent_ram: " fmt
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/device.h>
 #include <linux/err.h>
@@ -29,6 +20,16 @@
 #include <linux/vmalloc.h>
 #include <asm/page.h>
 
+/**
+ * struct persistent_ram_buffer - persistent circular RAM buffer
+ *
+ * @sig:
+ *	signature to indicate header (PERSISTENT_RAM_SIG xor PRZ-type value)
+ * @start:
+ *	offset into @data where the beginning of the stored bytes begin
+ * @size:
+ *	number of valid bytes stored in @data
+ */
 struct persistent_ram_buffer {
 	uint32_t    sig;
 	atomic_t    start;
@@ -347,7 +348,7 @@
 	int rem, ret = 0, c = count;
 	size_t start;
 
-	if (unlikely(!access_ok(VERIFY_READ, s, count)))
+	if (unlikely(!access_ok(s, count)))
 		return -EFAULT;
 	if (unlikely(c > prz->buffer_size)) {
 		s += c - prz->buffer_size;
@@ -438,12 +439,13 @@
 }
 
 static void *persistent_ram_iomap(phys_addr_t start, size_t size,
-		unsigned int memtype)
+		unsigned int memtype, char *label)
 {
 	void *va;
 
-	if (!request_mem_region(start, size, "persistent_ram")) {
-		pr_err("request mem region (0x%llx@0x%llx) failed\n",
+	if (!request_mem_region(start, size, label ?: "ramoops")) {
+		pr_err("request mem region (%s 0x%llx@0x%llx) failed\n",
+			label ?: "ramoops",
 			(unsigned long long)size, (unsigned long long)start);
 		return NULL;
 	}
@@ -470,7 +472,8 @@
 	if (pfn_valid(start >> PAGE_SHIFT))
 		prz->vaddr = persistent_ram_vmap(start, size, memtype);
 	else
-		prz->vaddr = persistent_ram_iomap(start, size, memtype);
+		prz->vaddr = persistent_ram_iomap(start, size, memtype,
+						  prz->label);
 
 	if (!prz->vaddr) {
 		pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
@@ -488,32 +491,42 @@
 				    struct persistent_ram_ecc_info *ecc_info)
 {
 	int ret;
+	bool zap = !!(prz->flags & PRZ_FLAG_ZAP_OLD);
 
 	ret = persistent_ram_init_ecc(prz, ecc_info);
-	if (ret)
+	if (ret) {
+		pr_warn("ECC failed %s\n", prz->label);
 		return ret;
+	}
 
 	sig ^= PERSISTENT_RAM_SIG;
 
 	if (prz->buffer->sig == sig) {
+		if (buffer_size(prz) == 0) {
+			pr_debug("found existing empty buffer\n");
+			return 0;
+		}
+
 		if (buffer_size(prz) > prz->buffer_size ||
-		    buffer_start(prz) > buffer_size(prz))
+		    buffer_start(prz) > buffer_size(prz)) {
 			pr_info("found existing invalid buffer, size %zu, start %zu\n",
 				buffer_size(prz), buffer_start(prz));
-		else {
+			zap = true;
+		} else {
 			pr_debug("found existing buffer, size %zu, start %zu\n",
 				 buffer_size(prz), buffer_start(prz));
 			persistent_ram_save_old(prz);
-			return 0;
 		}
 	} else {
 		pr_debug("no valid data in buffer (sig = 0x%08x)\n",
 			 prz->buffer->sig);
+		prz->buffer->sig = sig;
+		zap = true;
 	}
 
-	/* Rewind missing or invalid memory area. */
-	prz->buffer->sig = sig;
-	persistent_ram_zap(prz);
+	/* Reset missing, invalid, or single-use memory area. */
+	if (zap)
+		persistent_ram_zap(prz);
 
 	return 0;
 }
@@ -541,12 +554,13 @@
 	prz->ecc_info.par = NULL;
 
 	persistent_ram_free_old(prz);
+	kfree(prz->label);
 	kfree(prz);
 }
 
 struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
 			u32 sig, struct persistent_ram_ecc_info *ecc_info,
-			unsigned int memtype, u32 flags)
+			unsigned int memtype, u32 flags, char *label)
 {
 	struct persistent_ram_zone *prz;
 	int ret = -ENOMEM;
@@ -560,6 +574,7 @@
 	/* Initialize general buffer state. */
 	raw_spin_lock_init(&prz->buffer_lock);
 	prz->flags = flags;
+	prz->label = label;
 
 	ret = persistent_ram_buffer_map(start, size, prz, memtype);
 	if (ret)
@@ -569,6 +584,12 @@
 	if (ret)
 		goto err;
 
+	pr_debug("attached %s 0x%zx@0x%llx: %zu header, %zu data, %zu ecc (%d/%d)\n",
+		prz->label, prz->size, (unsigned long long)prz->paddr,
+		sizeof(*prz->buffer), prz->buffer_size,
+		prz->size - sizeof(*prz->buffer) - prz->buffer_size,
+		prz->ecc_info.ecc_size, prz->ecc_info.block_size);
+
 	return prz;
 err:
 	persistent_ram_free(prz);