[PATCH 2/2] kmsg_dump: adding to reboot, halt, poweroff andemergency_restart path

[Seiji Aguchi]

 We need to know the reason why system rebooted in support service.
 However, we can't inform our customers of the reason because
 final messages are lost on current Linux kernel.
 
 This patch improves the situation above because the final messages 
 are saved by adding kmsg_dump() to reboot, halt, poweroff and 
 emergency_restart path.

 Signed-off-by: Seiji Aguchi <seiji.aguchi@xxxxxxx>

---
 include/linux/kmsg_dump.h |    4 ++++
 kernel/printk.c           |    4 ++++
 kernel/sys.c              |    6 ++++++
 3 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h
index 24b4414..2a0d7d6 100644
--- a/include/linux/kmsg_dump.h
+++ b/include/linux/kmsg_dump.h
@@ -18,6 +18,10 @@ enum kmsg_dump_reason {
 	KMSG_DUMP_OOPS,
 	KMSG_DUMP_PANIC,
 	KMSG_DUMP_KEXEC,
+	KMSG_DUMP_RESTART,
+	KMSG_DUMP_HALT,
+	KMSG_DUMP_POWEROFF,
+	KMSG_DUMP_EMERG,
 };
 
 /**
diff --git a/kernel/printk.c b/kernel/printk.c
index b2ebaee..c5648b4 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -1516,6 +1516,10 @@ static const char * const kmsg_reasons[] = {
 	[KMSG_DUMP_OOPS]	= "oops",
 	[KMSG_DUMP_PANIC]	= "panic",
 	[KMSG_DUMP_KEXEC]	= "kexec",
+	[KMSG_DUMP_RESTART]	= "restart",
+	[KMSG_DUMP_HALT]	= "halt",
+	[KMSG_DUMP_POWEROFF]	= "poweroff",
+	[KMSG_DUMP_EMERG]	= "emergency_restart",
 };
 
 static const char *kmsg_to_str(enum kmsg_dump_reason reason)
diff --git a/kernel/sys.c b/kernel/sys.c
index 7f5a0cd..3eab886 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -43,6 +43,8 @@
 #include <linux/kprobes.h>
 #include <linux/user_namespace.h>
 
+#include <linux/kmsg_dump.h>
+
 #include <asm/uaccess.h>
 #include <asm/io.h>
 #include <asm/unistd.h>
@@ -285,6 +287,7 @@ out_unlock:
  */
 void emergency_restart(void)
 {
+	kmsg_dump(KMSG_DUMP_EMERG);
 	machine_emergency_restart();
 }
 EXPORT_SYMBOL_GPL(emergency_restart);
@@ -312,6 +315,7 @@ void kernel_restart(char *cmd)
 		printk(KERN_EMERG "Restarting system.\n");
 	else
 		printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
+	kmsg_dump(KMSG_DUMP_RESTART);
 	machine_restart(cmd);
 }
 EXPORT_SYMBOL_GPL(kernel_restart);
@@ -333,6 +337,7 @@ void kernel_halt(void)
 	kernel_shutdown_prepare(SYSTEM_HALT);
 	sysdev_shutdown();
 	printk(KERN_EMERG "System halted.\n");
+	kmsg_dump(KMSG_DUMP_HALT);
 	machine_halt();
 }
 
@@ -351,6 +356,7 @@ void kernel_power_off(void)
 	disable_nonboot_cpus();
 	sysdev_shutdown();
 	printk(KERN_EMERG "Power down.\n");
+	kmsg_dump(KMSG_DUMP_POWEROFF);
 	machine_power_off();
 }
 EXPORT_SYMBOL_GPL(kernel_power_off);
-- 
1.7.2.2
¢éì®&Þ~º&¶¬–+-±éÝ¥Šw®žË±Êâmébžìdz¹Þ)í…æèw*jg¬±¨¶‰šŽŠÝj/êäz¹ÞŠà2ŠÞ¨è­Ú&¢)ß«a¶Úþø®G«éh®æj:+v‰¨Šwè†Ù>Wš±êÞiÛaxPjØm¶ŸÿÃ-»+ƒùdš_