[S390] kernel: Add OS info memory interface

In order to allow kdump based stand-alone dump, some information
has to be passed from the old kernel to the new dump kernel. This
is done via a the struct "os_info" that contains the following fields:
 * crashkernel base and size
 * reipl block
 * vmcoreinfo
 * init function
A pointer to os_info is stored at a well known storage location
and the whole structure as well as all fields are secured with
checksums.

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

1 files changed, 13 insertions, 0 deletions

diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index d15b6c937088..3b9e5c9f4c0b 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -41,6 +41,7 @@
 #include <asm/sclp.h>
 #include <asm/vdso.h>
 #include <asm/debug.h>
+#include <asm/os_info.h>
 #include "entry.h"
 
 enum {
@@ -826,6 +827,17 @@ void __noreturn cpu_die(void)
 
 #endif /* CONFIG_HOTPLUG_CPU */
 
+static void smp_call_os_info_init_fn(void)
+{
+        int (*init_fn)(void);
+        unsigned long size;
+
+        init_fn = os_info_old_entry(OS_INFO_INIT_FN, &size);
+        if (!init_fn)
+                return;
+        init_fn();
+}
+
 void __init smp_prepare_cpus(unsigned int max_cpus)
 {
         /* request the 0x1201 emergency signal external interrupt */
@@ -834,6 +846,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
         /* request the 0x1202 external call external interrupt */
         if (register_external_interrupt(0x1202, do_ext_call_interrupt) != 0)
                 panic("Couldn't request external interrupt 0x1202");
+        smp_call_os_info_init_fn();
         smp_detect_cpus();
 }