[S390] add support for compressed kernels

Add the "bzImage" compile target and the necessary code  to generate
compressed kernel images. The old style uncompressed "image" target
is preserved, a simple make will build them both.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/Makefile b/arch/s390/Makefile
index fc8fb20..0da1074 100644
--- a/arch/s390/Makefile
+++ b/arch/s390/Makefile
@@ -14,6 +14,7 @@
 #
 
 ifndef CONFIG_64BIT
+LD_BFD		:= elf32-s390
 LDFLAGS		:= -m elf_s390
 KBUILD_CFLAGS	+= -m31
 KBUILD_AFLAGS	+= -m31
@@ -21,6 +22,7 @@
 STACK_SIZE	:= 8192
 CHECKFLAGS	+= -D__s390__ -msize-long
 else
+LD_BFD		:= elf64-s390
 LDFLAGS		:= -m elf64_s390
 MODFLAGS	+= -fpic -D__PIC__
 KBUILD_CFLAGS	+= -m64
@@ -30,6 +32,8 @@
 CHECKFLAGS	+= -D__s390__ -D__s390x__
 endif
 
+export LD_BFD
+
 cflags-$(CONFIG_MARCH_G5)   += $(call cc-option,-march=g5)
 cflags-$(CONFIG_MARCH_Z900) += $(call cc-option,-march=z900)
 cflags-$(CONFIG_MARCH_Z990) += $(call cc-option,-march=z990)
@@ -85,7 +89,9 @@
 OBJCOPYFLAGS	:= -O binary
 LDFLAGS_vmlinux := -e start
 
-head-y		:= arch/s390/kernel/head.o arch/s390/kernel/init_task.o
+head-y		:= arch/s390/kernel/head.o
+head-y		+= arch/s390/kernel/$(if $(CONFIG_64BIT),head64.o,head31.o)
+head-y		+= arch/s390/kernel/init_task.o
 
 core-y		+= arch/s390/mm/ arch/s390/kernel/ arch/s390/crypto/ \
 		   arch/s390/appldata/ arch/s390/hypfs/ arch/s390/kvm/
@@ -99,12 +105,12 @@
 
 boot		:= arch/s390/boot
 
-all: image
+all: image bzImage
 
 install: vmlinux
 	$(Q)$(MAKE) $(build)=$(boot) $@
 
-image: vmlinux
+image bzImage: vmlinux
 	$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
 
 zfcpdump:
@@ -116,4 +122,5 @@
 # Don't use tabs in echo arguments
 define archhelp
   echo  '* image           - Kernel image for IPL ($(boot)/image)'
+  echo	'* bzImage         - Compressed kernel image for IPL ($(boot)/bzImage)'
 endef