s390/setup: generate asm offsets from struct parmarea

To reduce duplication, replace error-prone and hard-coded parameter area
offsets with auto-generated ones.
Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

arch/s390/include/asm/setup.h

@@ -44,15 +44,6 @@
 #define STARTUP_NORMAL_OFFSET	0x10000
 #define STARTUP_KDUMP_OFFSET	0x10010
 
-/* Offsets to parameters in kernel/head.S  */
-
-#define IPL_DEVICE	0x10400
-#define INITRD_START	0x10408
-#define INITRD_SIZE	0x10410
-#define OLDMEM_BASE	0x10418
-#define OLDMEM_SIZE	0x10420
-#define COMMAND_LINE	0x10480
-
 #ifndef __ASSEMBLY__
 
 #include <asm/lowcore.h>

arch/s390/kernel/asm-offsets.c

@@ -152,5 +152,12 @@ int main(void)
 	DEFINE(__KEXEC_SHA_REGION_SIZE, sizeof(struct kexec_sha_region));
 	/* sizeof kernel parameter area */
 	DEFINE(__PARMAREA_SIZE, sizeof(struct parmarea));
+	/* kernel parameter area offsets */
+	DEFINE(IPL_DEVICE, PARMAREA + offsetof(struct parmarea, ipl_device));
+	DEFINE(INITRD_START, PARMAREA + offsetof(struct parmarea, initrd_start));
+	DEFINE(INITRD_SIZE, PARMAREA + offsetof(struct parmarea, initrd_size));
+	DEFINE(OLDMEM_BASE, PARMAREA + offsetof(struct parmarea, oldmem_base));
+	DEFINE(OLDMEM_SIZE, PARMAREA + offsetof(struct parmarea, oldmem_size));
+	DEFINE(COMMAND_LINE, PARMAREA + offsetof(struct parmarea, command_line));
 	return 0;
 }