pstore: Split pstore fragile flags

This patch adds new PSTORE_FLAGS for each pstore type so that they can
be enabled separately.  This is a preparation for ongoing virtio-pstore
work to support those types flexibly.

The PSTORE_FLAGS_FRAGILE is changed to PSTORE_FLAGS_DMESG to preserve the
original behavior.

Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: linux-acpi@vger.kernel.org
Cc: linux-efi@vger.kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
[kees: retained "FRAGILE" for now to make merges easier]
Signed-off-by: Kees Cook <keescook@chromium.org>

drivers/acpi/apei/erst.c

@@ -938,7 +938,7 @@ static int erst_clearer(enum pstore_type_id type, u64 id, int count,
 static struct pstore_info erst_info = {
 	.owner		= THIS_MODULE,
 	.name		= "erst",
-	.flags		= PSTORE_FLAGS_FRAGILE,
+	.flags		= PSTORE_FLAGS_DMESG,
 	.open		= erst_open_pstore,
 	.close		= erst_close_pstore,
 	.read		= erst_reader,

drivers/firmware/efi/efi-pstore.c

@@ -362,7 +362,7 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
 static struct pstore_info efi_pstore_info = {
 	.owner		= THIS_MODULE,
 	.name		= "efi",
-	.flags		= PSTORE_FLAGS_FRAGILE,
+	.flags		= PSTORE_FLAGS_DMESG,
 	.open		= efi_pstore_open,
 	.close		= efi_pstore_close,
 	.read		= efi_pstore_read,

fs/pstore/platform.c

@@ -659,13 +659,14 @@ int pstore_register(struct pstore_info *psi)
 	if (pstore_is_mounted())
 		pstore_get_records(0);
 
+	if (psi->flags & PSTORE_FLAGS_DMESG)
 		pstore_register_kmsg();
-
-	if ((psi->flags & PSTORE_FLAGS_FRAGILE) == 0) {
+	if (psi->flags & PSTORE_FLAGS_CONSOLE)
 		pstore_register_console();
+	if (psi->flags & PSTORE_FLAGS_FTRACE)
 		pstore_register_ftrace();
+	if (psi->flags & PSTORE_FLAGS_PMSG)
 		pstore_register_pmsg();
-	}
 
 	if (pstore_update_ms >= 0) {
 		pstore_timer.expires = jiffies +
@@ -689,11 +690,13 @@ EXPORT_SYMBOL_GPL(pstore_register);
 
 void pstore_unregister(struct pstore_info *psi)
 {
-	if ((psi->flags & PSTORE_FLAGS_FRAGILE) == 0) {
+	if (psi->flags & PSTORE_FLAGS_PMSG)
 		pstore_unregister_pmsg();
+	if (psi->flags & PSTORE_FLAGS_FTRACE)
 		pstore_unregister_ftrace();
+	if (psi->flags & PSTORE_FLAGS_CONSOLE)
 		pstore_unregister_console();
-	}
+	if (psi->flags & PSTORE_FLAGS_DMESG)
 		pstore_unregister_kmsg();
 
 	free_buf_for_compression();

fs/pstore/ram.c

@@ -623,6 +623,8 @@ static int ramoops_probe(struct platform_device *pdev)
 		goto fail_clear;
 	}
 
+	cxt->pstore.flags = PSTORE_FLAGS_ALL;
+
 	err = pstore_register(&cxt->pstore);
 	if (err) {
 		pr_err("registering with pstore failed\n");

include/linux/pstore.h

@@ -74,7 +74,13 @@ struct pstore_info {
 	void		*data;
 };
 
-#define	PSTORE_FLAGS_FRAGILE	1
+#define PSTORE_FLAGS_DMESG	(1 << 0)
+#define PSTORE_FLAGS_FRAGILE	PSTORE_FLAGS_DMESG
+#define PSTORE_FLAGS_CONSOLE	(1 << 1)
+#define PSTORE_FLAGS_FTRACE	(1 << 2)
+#define PSTORE_FLAGS_PMSG	(1 << 3)
+
+#define PSTORE_FLAGS_ALL	((1 << 4) - 1)
 
 extern int pstore_register(struct pstore_info *);
 extern void pstore_unregister(struct pstore_info *);