[S390] kernel: Add z/VM LGR detection

Currently the following mechanisms are available to move active
Linux on System z instances between machines:
* z/VM 6.2 SSI (Single System Image)
* Suspend/resume
For moving Linux instances in this patch the term LGR (Linux Guest
Relocation) is used. Because such an operation is critical, it
should be detectable from Linux. With this patch for both, a live
system and a kernel dump, the information about LGRs is accessible.
To identify a guest, stsi and stfle data is used. A new function
lgr_info_log() compares the current data (lgr_info_cur) with the
last recorded one (lgr_info_last). In case the two data sets differ,
lgr_info_cur is logged to the "lgr" s390dbf.

The following trigger points call lgr_info_log():
* panic
* die
* kdump
* LGR timer
* PSW restart
* QDIO recovery
* resume

This patch also changes the s390dbf hex_ascii view. Now only printable ASCII
characters are shown.

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index 9e2f6f7c0e5a..153e21ce2336 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -17,6 +17,7 @@
 #include <linux/fs.h>
 #include <linux/gfp.h>
 #include <linux/crash_dump.h>
+#include <linux/debug_locks.h>
 #include <asm/ipl.h>
 #include <asm/smp.h>
 #include <asm/setup.h>
@@ -26,6 +27,7 @@
 #include <asm/reset.h>
 #include <asm/sclp.h>
 #include <asm/checksum.h>
+#include <asm/debug.h>
 #include "entry.h"
 
 #define IPL_PARM_BLOCK_VERSION 0
@@ -1692,6 +1694,7 @@ static struct kobj_attribute on_panic_attr =
 
 static void do_panic(void)
 {
+	lgr_info_log();
 	on_panic_trigger.action->fn(&on_panic_trigger);
 	stop_run(&on_panic_trigger);
 }
@@ -1729,6 +1732,9 @@ static void __do_restart(void *ignore)
 
 void do_restart(void)
 {
+	tracing_off();
+	debug_locks_off();
+	lgr_info_log();
 	smp_call_online_cpu(__do_restart, NULL);
 }