[PATCH 3/3] kbuild: support generating stripped ELF files for PBL

[Ahmad Fatoum]

For testing remoteproc and ELF loading mechanisms, it can be useful
to have the consumed ELF files result from the barebox build itself.

The *.pblb intermediate artifacts can be used for this purpose, but they
are at least 64K larger than need be, because of generous alignment in
addition to debug and symbol information.

Let's add a separate %.elf target, that behaves like %.pblb with the
difference that the result is stripped and alignment of sections on-disk
is disabled.

Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 Makefile        |  4 ++--
 images/Makefile | 10 +++++++---
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index f86d76076fb7..0e579eb804f2 100644
--- a/Makefile
+++ b/Makefile
@@ -470,6 +470,7 @@ LDFLAGS_common += $(call ld-option,--no-warn-rwx-segments)
 
 LDFLAGS_barebox += $(LDFLAGS_common)
 LDFLAGS_pbl += $(LDFLAGS_common)
+LDFLAGS_elf += $(LDFLAGS_common) --nmagic -s
 
 export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE LD CC
 export CPP AR NM STRIP OBJCOPY OBJDUMP MAKE AWK GENKSYMS PERL PYTHON3 UTS_MACHINE
@@ -483,8 +484,7 @@ export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE
 export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE
 export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE
 export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL
-export LDFLAGS_barebox
-export LDFLAGS_pbl
+export LDFLAGS_barebox LDFLAGS_pbl LDFLAGS_elf
 
 export CFLAGS_UBSAN
 export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE
diff --git a/images/Makefile b/images/Makefile
index c1cb56f5b189..9739a15c06ba 100644
--- a/images/Makefile
+++ b/images/Makefile
@@ -57,9 +57,9 @@ $(pbl-lds): $(obj)/../arch/$(SRCARCH)/lib/pbl.lds.S FORCE
 	$(call if_changed_dep,cpp_lds_S)
 
 quiet_cmd_elf__ ?= LD      $@
-      cmd_elf__ ?= $(LD) $(LDFLAGS_pbl) --gc-sections		\
+      cmd_elf__ ?= $(LD) $(LDFLAGS_$(patsubst .%,%,$(suffix $(@F)))) 	\
 		-e $(2) -Map $@.map $(LDFLAGS_$(@F)) -o $@		\
-		--defsym=__pbl_board_entry=$(2)  			\
+		--gc-sections --defsym=__pbl_board_entry=$(2)  		\
 		-T $(pbl-lds)						\
 		--whole-archive $(BAREBOX_PBL_OBJS) $(obj)/piggy.o	\
 		$(obj)/sha_sum.o
@@ -70,6 +70,10 @@ $(obj)/%.pbl: $(pbl-lds) $(BAREBOX_PBL_OBJS) $(obj)/piggy.o $(obj)/sha_sum.o FOR
 	$(call if_changed,elf__,$(*F))
 	$(call cmd,prelink__)
 
+$(obj)/%.elf: $(pbl-lds) $(BAREBOX_PBL_OBJS) $(obj)/piggy.o $(obj)/sha_sum.o FORCE
+	$(call if_changed,elf__,$(*F))
+	$(call cmd,prelink__)
+
 $(obj)/%.pblb: $(obj)/%.pbl FORCE
 	$(call if_changed,objcopy_bin,$(*F))
 	$(Q)$(OBJCOPY) -O binary --only-section=.missing_fw $< $@.missing-firmware
@@ -218,7 +222,7 @@ $(flash-link): $(link-dest) FORCE
 $(flash-list): $(image-y-path)
 	@for i in $^; do if [ -s $$i ]; then echo $$i; fi; done > $@
 
-clean-files := *.pbl *.pblb *.map start_*.imximg *.img barebox.z start_*.kwbimg \
+clean-files := *.pbl *.pblb *.elf *.map start_*.imximg *.img barebox.z start_*.kwbimg \
 	start_*.kwbuartimg *.socfpgaimg *.mlo *.t20img *.t20img.cfg *.t30img \
 	*.t30img.cfg *.t124img *.t124img.cfg *.mlospi *.mlo *.mxsbs *.mxssd *.rkimg \
 	start_*.simximg start_*.usimximg *.zynqimg *.image *.swapped *.missing-firmware
-- 
2.39.2