[S390] Export vmcoreinfo note

This patch defines for s390 an ABI defined pointer to the vmcoreinfo note at
a well known address. With this patch tools are able to find this information
in dumps created by stand-alone or hypervisor dump tools.

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

2 files changed, 16 insertions, 4 deletions

diff --git a/arch/s390/include/asm/lowcore.h b/arch/s390/include/asm/lowcore.h
index e85c911aabf0..4f990a5e5b59 100644
--- a/arch/s390/include/asm/lowcore.h
+++ b/arch/s390/include/asm/lowcore.h
@@ -151,10 +151,11 @@ struct _lowcore {
          */
         __u32   ipib;                           /* 0x0e00 */
         __u32   ipib_checksum;                  /* 0x0e04 */
+        __u32   vmcore_info;                    /* 0x0e08 */
 
         /* 64 bit save area */
-        __u64   save_area_64;                   /* 0x0e08 */
-        __u8    pad_0x0e10[0x0f00-0x0e10];      /* 0x0e10 */
+        __u64   save_area_64;                   /* 0x0e0c */
+        __u8    pad_0x0e14[0x0f00-0x0e14];      /* 0x0e14 */
 
         /* Extended facility list */
         __u64   stfle_fac_list[32];             /* 0x0f00 */
@@ -290,10 +291,11 @@ struct _lowcore {
          */
         __u64   ipib;                           /* 0x0e00 */
         __u32   ipib_checksum;                  /* 0x0e08 */
+        __u64   vmcore_info;                    /* 0x0e0c */
 
         /* 64 bit save area */
-        __u64   save_area_64;                   /* 0x0e0c */
-        __u8    pad_0x0e14[0x0f00-0x0e14];      /* 0x0e14 */
+        __u64   save_area_64;                   /* 0x0e14 */
+        __u8    pad_0x0e1c[0x0f00-0x0e1c];      /* 0x0e1c */
 
         /* Extended facility list */
         __u64   stfle_fac_list[32];             /* 0x0f00 */
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index b5a30412b2e5..63c81de665ec 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -558,6 +558,15 @@ static void __init setup_restart_psw(void)
         copy_to_absolute_zero(&S390_lowcore.restart_psw, &psw, sizeof(psw));
 }
 
+static void __init setup_vmcoreinfo(void)
+{
+#ifdef CONFIG_KEXEC
+        unsigned long ptr = paddr_vmcoreinfo_note();
+
+        copy_to_absolute_zero(&S390_lowcore.vmcore_info, &ptr, sizeof(ptr));
+#endif
+}
+
 #ifdef CONFIG_CRASH_DUMP
 
 /*
@@ -1022,6 +1031,7 @@ setup_arch(char **cmdline_p)
         reserve_crashkernel();
         setup_memory();
         setup_resources();
+        setup_vmcoreinfo();
         setup_restart_psw();
         setup_lowcore();