[PATCH v2 18/23] sys-rq: Add option to soft dump

[Mike Waychison <mikew@google.com>]

It is very useful to provide some means to force the kernel logs to make it out
via the kmsg_oops implementations on the console.  Add a new option 'Y' to
sysrq to allow dumping of logs to kmsg_dumper drivers.

Signed-off-by: Mike Waychison <mikew@google.com>
---
 drivers/char/sysrq.c |   14 +++++++++++++-
 1 files changed, 13 insertions(+), 1 deletions(-)

diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c
index eaa5d3e..058d3c8 100644
--- a/drivers/char/sysrq.c
+++ b/drivers/char/sysrq.c
@@ -41,6 +41,7 @@
 #include <linux/oom.h>
 #include <linux/slab.h>
 #include <linux/input.h>
+#include <linux/kmsg_dump.h>
 
 #include <asm/ptrace.h>
 #include <asm/irq_regs.h>
@@ -395,6 +396,17 @@ static struct sysrq_key_op sysrq_unrt_op = {
 	.enable_mask	= SYSRQ_ENABLE_RTNICE,
 };
 
+static void sysrq_handle_softdump(int key)
+{
+	kmsg_dump(KMSG_DUMP_SOFT, NULL);
+}
+static struct sysrq_key_op sysrq_softdump_op = {
+	.handler	= sysrq_handle_softdump,
+	.help_msg	= "soft-dump(Y)",
+	.action_msg	= "Trigger a soft dump",
+	.enable_mask	= SYSRQ_ENABLE_DUMP,
+};
+
 /* Key Operations table and lock */
 static DEFINE_SPINLOCK(sysrq_key_table_lock);
 
@@ -451,7 +463,7 @@ static struct sysrq_key_op *sysrq_key_table[36] = {
 	/* x: May be registered on ppc/powerpc for xmon */
 	NULL,				/* x */
 	/* y: May be registered on sparc64 for global register dump */
-	NULL,				/* y */
+	&sysrq_softdump_op,		/* y */
 	&sysrq_ftrace_dump_op,		/* z */
 };