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...@hitachi.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: "H. Peter Anvin" <h...@zytor.com>
Cc: x...@kernel.org
Cc: Peter Zijlstra <a.p.zijls...@chello.nl>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: "Eric W. Biederman" <ebied...@xmission.com>
Cc: Al Viro <v...@zeniv.linux.org.uk>
Cc: linux-kernel@vger.kernel.org
---
arch/x86/Kconfig | 15 +++++++++++
kernel/Makefile | 1 +
kernel/livedump.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 89 insertions(+)
create mode 100644 kernel/livedump.c
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 50a1d1f..39c0813 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1734,6 +1734,21 @@ 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 c0cc67a..c8bd09b 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -110,6 +110,7 @@ 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..409f7ed
--- /dev/null
+++ b/kernel/livedump.c
@@ -0,0 +1,73 @@
+/* livedump.c - Live Dump's main
+ * Copyright (C) 2012 Hitachi, Ltd.
+ * Author: YOSHIDA Masanori <masanori.yoshida...@hitachi.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/kernel.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/reboot.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 const struct file_operations livedump_fops = {
+ .unlocked_ioctl = livedump_ioctl,
+};
+static struct miscdevice livedump_misc = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = DEVICE_NAME,
+ .fops = &livedump_fops,
+};
+
+static int livedump_exit(struct notifier_block *_, unsigned long __, void *___)
+{
+ misc_deregister(&livedump_misc);
+ return NOTIFY_DONE;
+}
+static struct notifier_block livedump_nb = {
+ .notifier_call = livedump_exit
+};
+
+static int __init livedump_init(void)
+{
+ int ret;
+
+ ret = misc_register(&livedump_misc);
+ if (WARN_ON(ret))
+ return ret;
+
+ ret = register_reboot_notifier(&livedump_nb);
+ if (WARN_ON(ret)) {
+ livedump_exit(NULL, 0, NULL);
+ return ret;
+ }
+
+ return 0;
+}
+device_initcall(livedump_init);
--
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