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Subject[PATCH 01/11] pstore: Add console log messages support
Date
Pstore doesn't support logging kernel messages in run-time, it only
dumps dmesg when kernel oopses/panics. This makes pstore useless for
debugging hangs caused by HW issues or improper use of HW (e.g.
weird device inserted -> driver tried to write a reserved bits ->
SoC hanged. In that case we don't get any messages in the pstore.

Therefore, let's add a runtime logging support: PSTORE_TYPE_CONSOLE.

Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Colin Cross <ccross@android.com>
---
fs/pstore/Kconfig | 7 +++++++
fs/pstore/inode.c | 3 +++
fs/pstore/platform.c | 37 +++++++++++++++++++++++++++++++++++++
include/linux/pstore.h | 1 +
4 files changed, 48 insertions(+)
diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
index 23ade26..d044de6 100644
--- a/fs/pstore/Kconfig
+++ b/fs/pstore/Kconfig
@@ -12,6 +12,13 @@ config PSTORE
If you don't have a platform persistent store driver,
say N.

+config PSTORE_CONSOLE
+ bool "Log kernel console messages"
+ depends on PSTORE
+ help
+ When the option is enabled, pstore will log all kernel
+ messages, even if no oops or panic happened.
+
config PSTORE_RAM
tristate "Log panic/oops to a RAM buffer"
depends on PSTORE
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index 49b40ea..fda1331 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -212,6 +212,9 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
case PSTORE_TYPE_DMESG:
sprintf(name, "dmesg-%s-%lld", psname, id);
break;
+ case PSTORE_TYPE_CONSOLE:
+ sprintf(name, "console-%s", psname);
+ break;
case PSTORE_TYPE_MCE:
sprintf(name, "mce-%s-%lld", psname, id);
break;
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 82c585f..61461ed 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -1,6 +1,7 @@
/*
* 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
@@ -22,6 +23,7 @@
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kmsg_dump.h>
+#include <linux/console.h>
#include <linux/module.h>
#include <linux/pstore.h>
#include <linux/string.h>
@@ -156,6 +158,40 @@ static struct kmsg_dumper pstore_dumper = {
.dump = pstore_dump,
};

+#ifdef CONFIG_PSTORE_CONSOLE
+static void pstore_console_write(struct console *con, const char *s, unsigned c)
+{
+ const char *e = s + c;
+
+ while (s < e) {
+ unsigned long flags;
+
+ if (c > psinfo->bufsize)
+ c = psinfo->bufsize;
+ spin_lock_irqsave(&psinfo->buf_lock, flags);
+ memcpy(psinfo->buf, s, c);
+ psinfo->write(PSTORE_TYPE_CONSOLE, 0, NULL, 0, c, psinfo);
+ spin_unlock_irqrestore(&psinfo->buf_lock, flags);
+ s += c;
+ c = e - s;
+ }
+}
+
+static struct console pstore_console = {
+ .name = "pstore",
+ .write = pstore_console_write,
+ .flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
+ .index = -1,
+};
+
+static void pstore_register_console(void)
+{
+ register_console(&pstore_console);
+}
+#else
+static void pstore_register_console(void) {}
+#endif
+
/*
* platform specific persistent storage driver registers with
* us here. If pstore is already mounted, call the platform
@@ -193,6 +229,7 @@ int pstore_register(struct pstore_info *psi)
pstore_get_records(0);

kmsg_dump_register(&pstore_dumper);
+ pstore_register_console();

pstore_timer.expires = jiffies + PSTORE_INTERVAL;
add_timer(&pstore_timer);
diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index e1461e1..1bd014b 100644
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -29,6 +29,7 @@
enum pstore_type_id {
PSTORE_TYPE_DMESG = 0,
PSTORE_TYPE_MCE = 1,
+ PSTORE_TYPE_CONSOLE = 2,
PSTORE_TYPE_UNKNOWN = 255
};

--
1.7.9.2


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