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Date: Fri, 25 May 2012 18:12:07 +0900
From: YOSHIDA Masanori <masanori.yoshida.tv@...achi.com>
To: "Thomas Gleixner" <tglx@...utronix.de>,
"Ingo Molnar" <mingo@...hat.com>, "H. Peter Anvin" <hpa@...or.com>,
x86@...nel.org, "Vivek Goyal" <vgoyal@...hat.com>,
linux-kernel@...r.kernel.org
Cc: "Andy Lutomirski" <luto@....edu>, "H. Peter Anvin" <hpa@...or.com>,
"Ingo Molnar" <mingo@...e.hu>, "Ingo Molnar" <mingo@...hat.com>,
"KOSAKI Motohiro" <kosaki.motohiro@...fujitsu.com>,
"Kees Cook" <keescook@...omium.org>,
"Kevin Hilman" <khilman@...com>,
"Peter Zijlstra" <a.p.zijlstra@...llo.nl>,
"Prarit Bhargava" <prarit@...hat.com>,
"Rafael J. Wysocki" <rjw@...k.pl>, "Tejun Heo" <tj@...nel.org>,
"Thomas Gleixner" <tglx@...utronix.de>,
linux-kernel@...r.kernel.org, x86@...nel.org,
yrl.pp-manager.tt@...achi.com
Subject: [RFC PATCH 2/4 V2] livedump: Add the new misc device "livedump"
Introduces the new misc device "livedump".
This device will be used as interface between livedump and user space.
Right now, the device only has empty ioctl operation.
***ATTENTION PLEASE***
I think debugfs is more suitable for this feature, but currently livedump
uses the misc device for simplicity. This will be fixed in the future.
Signed-off-by: YOSHIDA Masanori <masanori.yoshida.tv@...achi.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: x86@...nel.org
Cc: Kevin Hilman <khilman@...com>
Cc: "Rafael J. Wysocki" <rjw@...k.pl>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: linux-kernel@...r.kernel.org
---
arch/x86/Kconfig | 15 ++++++++++
kernel/Makefile | 1 +
kernel/livedump.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 99 insertions(+), 0 deletions(-)
create mode 100644 kernel/livedump.c
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c9866b0..4c97583 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1729,6 +1729,21 @@ config CMDLINE_OVERRIDE
This is used to work around broken boot loaders. This should
be set to 'N' under normal conditions.
+config LIVEDUMP
+ bool "Live Dump support"
+ depends on X86_64
+ ---help---
+ Set this option to 'Y' to allow the kernel support to acquire
+ a consistent snapshot of kernel space without stopping system.
+
+ This feature regularly causes small overhead on kernel.
+
+ Once this feature is initialized by its special ioctl, it
+ allocates huge memory for itself and causes much more overhead
+ on kernel.
+
+ If in doubt, say N.
+
endmenu
config ARCH_ENABLE_MEMORY_HOTPLUG
diff --git a/kernel/Makefile b/kernel/Makefile
index cb41b95..f095e7a 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -106,6 +106,7 @@ obj-$(CONFIG_USER_RETURN_NOTIFIER) += user-return-notifier.o
obj-$(CONFIG_PADATA) += padata.o
obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
obj-$(CONFIG_JUMP_LABEL) += jump_label.o
+obj-$(CONFIG_LIVEDUMP) += livedump.o
$(obj)/configs.o: $(obj)/config_data.h
diff --git a/kernel/livedump.c b/kernel/livedump.c
new file mode 100644
index 0000000..3103292
--- /dev/null
+++ b/kernel/livedump.c
@@ -0,0 +1,83 @@
+/* livedump.c - Live Dump's main
+ * Copyright (C) 2012 Hitachi, Ltd.
+ * Author: YOSHIDA Masanori <masanori.yoshida.tv@...achi.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * 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 Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+
+#define DEVICE_NAME "livedump"
+
+#define LIVEDUMP_IOC(x) _IO(0xff, x)
+
+static long livedump_ioctl(
+ struct file *file, unsigned int cmd, unsigned long arg)
+{
+ switch (cmd) {
+ default:
+ return -ENOIOCTLCMD;
+ }
+}
+
+static int livedump_open(struct inode *inode, struct file *file)
+{
+ if (!try_module_get(THIS_MODULE))
+ return -ENOENT;
+ return 0;
+}
+
+static int livedump_release(struct inode *inode, struct file *file)
+{
+ module_put(THIS_MODULE);
+ return 0;
+}
+
+static const struct file_operations livedump_fops = {
+ .unlocked_ioctl = livedump_ioctl,
+ .open = livedump_open,
+ .release = livedump_release,
+};
+static struct miscdevice livedump_misc = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = DEVICE_NAME,
+ .fops = &livedump_fops,
+};
+
+static int livedump_module_init(void)
+{
+ int ret;
+
+ ret = misc_register(&livedump_misc);
+ if (WARN(ret,
+ "livedump: Failed to register livedump on misc device.\n"
+ ))
+ return ret;
+
+ return 0;
+}
+module_init(livedump_module_init);
+
+static void livedump_module_exit(void)
+{
+ misc_deregister(&livedump_misc);
+}
+module_exit(livedump_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Livedump kernel module");
--
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