[S390] Add PSW restart shutdown trigger

With this patch a new S390 shutdown trigger "restart" is added. If under
z/VM "systerm restart" is entered or under the HMC the "PSW restart" button
is pressed, the PSW located at 0 (31 bit) or 0x1a0 (64 bit) bit is loaded.
Now we execute do_restart() that processes the restart action that is
defined under /sys/firmware/shutdown_actions/on_restart. Currently the
following actions are possible: reipl (default), stop, vmcmd, dump, and
dump_reipl.

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

2 files changed, 10 insertions, 2 deletions

diff --git a/arch/s390/include/asm/lowcore.h b/arch/s390/include/asm/lowcore.h
index f26280d9e88d..e85c911aabf0 100644
--- a/arch/s390/include/asm/lowcore.h
+++ b/arch/s390/include/asm/lowcore.h
@@ -18,6 +18,7 @@ void system_call(void);
 void pgm_check_handler(void);
 void mcck_int_handler(void);
 void io_int_handler(void);
+void psw_restart_int_handler(void);
 
 #ifdef CONFIG_32BIT
 
@@ -150,7 +151,10 @@ struct _lowcore {
          */
         __u32   ipib;                           /* 0x0e00 */
         __u32   ipib_checksum;                  /* 0x0e04 */
-        __u8    pad_0x0e08[0x0f00-0x0e08];      /* 0x0e08 */
+
+        /* 64 bit save area */
+        __u64   save_area_64;                   /* 0x0e08 */
+        __u8    pad_0x0e10[0x0f00-0x0e10];      /* 0x0e10 */
 
         /* Extended facility list */
         __u64   stfle_fac_list[32];             /* 0x0f00 */
@@ -286,7 +290,10 @@ struct _lowcore {
          */
         __u64   ipib;                           /* 0x0e00 */
         __u32   ipib_checksum;                  /* 0x0e08 */
-        __u8    pad_0x0e0c[0x0f00-0x0e0c];      /* 0x0e0c */
+
+        /* 64 bit save area */
+        __u64   save_area_64;                   /* 0x0e0c */
+        __u8    pad_0x0e14[0x0f00-0x0e14];      /* 0x0e14 */
 
         /* Extended facility list */
         __u64   stfle_fac_list[32];             /* 0x0f00 */
diff --git a/arch/s390/include/asm/system.h b/arch/s390/include/asm/system.h
index d382629a0172..6582f69f2389 100644
--- a/arch/s390/include/asm/system.h
+++ b/arch/s390/include/asm/system.h
@@ -113,6 +113,7 @@ extern void pfault_fini(void);
 
 extern void cmma_init(void);
 extern int memcpy_real(void *, void *, size_t);
+extern void copy_to_absolute_zero(void *dest, void *src, size_t count);
 
 #define finish_arch_switch(prev) do {                                        \
         set_fs(current->thread.mm_segment);                                  \