s390/decompressor: avoid reusing uncompressed image objects

Re-compile ebcdic.c and sclp_early_core.c for the decompressor,
using proper decompressor CFLAGS. This also allows to potentially use
instrumentation for those files when built for the main kernel image.

With kbuild there is no easy way to re-compile a source file from
another directory. Bypass ugly rules and Makefile meta-programming
with relative path includes of original files.

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/boot/Makefile

@@ -15,14 +15,18 @@ KBUILD_CFLAGS := $(KBUILD_CFLAGS_DECOMPRESSOR)
 # message if the kernel is started on a machine which is too old
 #
 ifneq ($(CC_FLAGS_MARCH),-march=z900)
-AFLAGS_REMOVE_head.o	+= $(CC_FLAGS_MARCH)
-AFLAGS_head.o		+= -march=z900
-CFLAGS_REMOVE_als.o	+= $(CC_FLAGS_MARCH)
-CFLAGS_als.o		+= -march=z900
+AFLAGS_REMOVE_head.o		+= $(CC_FLAGS_MARCH)
+AFLAGS_head.o			+= -march=z900
+CFLAGS_REMOVE_als.o		+= $(CC_FLAGS_MARCH)
+CFLAGS_als.o			+= -march=z900
+CFLAGS_REMOVE_sclp_early_core.o	+= $(CC_FLAGS_MARCH)
+CFLAGS_sclp_early_core.o	+= -march=z900
 endif
 
-obj-y	:= head.o als.o
-targets	:= bzImage startup.a $(obj-y)
+CFLAGS_sclp_early_core.o += -I$(srctree)/drivers/s390/char
+
+obj-y	:= head.o als.o ebcdic.o sclp_early_core.o
+targets	:= bzImage setup.a $(obj-y)
 subdir-	:= compressed
 
 OBJECTS := $(addprefix $(obj)/,$(obj-y))

arch/s390/boot/compressed/Makefile

@@ -16,9 +16,7 @@ targets += misc.o piggy.o sizes.h head.o
 KBUILD_AFLAGS := $(KBUILD_AFLAGS_DECOMPRESSOR)
 KBUILD_CFLAGS := $(KBUILD_CFLAGS_DECOMPRESSOR)
 
-OBJECTS := $(objtree)/arch/s390/kernel/ebcdic.o
-OBJECTS += $(objtree)/drivers/s390/char/sclp_early_core.o
-OBJECTS += $(obj)/head.o $(obj)/misc.o $(obj)/piggy.o
+OBJECTS := $(obj)/head.o $(obj)/misc.o $(obj)/piggy.o
 
 LDFLAGS_vmlinux := --oformat $(LD_BFD) -e startup -T
 $(obj)/vmlinux: $(obj)/vmlinux.lds $(objtree)/arch/s390/boot/startup.a $(OBJECTS)

arch/s390/boot/ebcdic.c

@@ -0,0 +1,2 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "../kernel/ebcdic.c"

arch/s390/boot/sclp_early_core.c

@@ -0,0 +1,2 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "../../../drivers/s390/char/sclp_early_core.c"

drivers/s390/char/Makefile

@@ -12,11 +12,6 @@ GCOV_PROFILE_sclp_early_core.o		:= n
 KCOV_INSTRUMENT_sclp_early_core.o	:= n
 UBSAN_SANITIZE_sclp_early_core.o	:= n
 
-ifneq ($(CC_FLAGS_MARCH),-march=z900)
-CFLAGS_REMOVE_sclp_early_core.o	+= $(CC_FLAGS_MARCH)
-CFLAGS_sclp_early_core.o		+= -march=z900
-endif
-
 CFLAGS_sclp_early_core.o		+= -D__NO_FORTIFY
 
 CFLAGS_REMOVE_sclp_early_core.o	+= $(CC_FLAGS_EXPOLINE)