Commit 7ae4a78d authored by Masahiro Yamada's avatar Masahiro Yamada Committed by Russell King
Browse files

ARM: 8969/1: decompressor: simplify libfdt builds 



Copying source files during the build time may not end up with
as clean code as expected.

lib/fdt*.c simply wrap scripts/dtc/libfdt/fdt*.c, and it works
nicely. Let's follow this approach for the arm decompressor, too.

Add four wrappers, arch/arm/boot/compressed/fdt*.c and remove
the Makefile messes. Another nice thing is we no longer need to
maintain the own libfdt_env.h because the decompressor can include
<linux/libfdt_env.h>.

There is a subtle problem when generated files are turned into
check-in files.

When you are doing a rebuild of an existing object tree with O=
option, there exists stale "shipped" copies that the old Makefile
implementation created. The build system ends up with compiling the
stale generated files because Make searches for prerequisites in the
current directory, i.e. $(objtree) first, and then the directory
listed in VPATH, i.e. $(srctree).

To mend this issue, I added the following code:

  ifdef building_out_of_srctree
  $(shell rm -f $(addprefix $(obj)/, fdt_rw.c fdt_ro.c fdt_wip.c fdt.c))
  endif

This will need to stay for a while because "git bisect" crossing this
commit, otherwise, would result in a build error.

Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
parent 4f39467e

arch/arm/boot/compressed/.gitignore

+0 −9
Original line number Diff line number Diff line
@@ -7,12 +7,3 @@ hyp-stub.S 
piggy_data

vmlinux

vmlinux.lds
 


# borrowed libfdt files

fdt.c

fdt.h

fdt_ro.c

fdt_rw.c

fdt_wip.c

libfdt.h

libfdt_internal.h

arch/arm/boot/compressed/Makefile

+15 −23
Original line number Diff line number Diff line
@@ -76,29 +76,30 @@ compress-$(CONFIG_KERNEL_LZMA) = lzma 
compress-$(CONFIG_KERNEL_XZ)   = xzkern

compress-$(CONFIG_KERNEL_LZ4)  = lz4



# Borrowed libfdt files for the ATAG compatibility mode



libfdt		:= fdt_rw.c fdt_ro.c fdt_wip.c fdt.c

libfdt_hdrs	:= fdt.h libfdt.h libfdt_internal.h



libfdt_objs	:= $(addsuffix .o, $(basename $(libfdt)))



$(addprefix $(obj)/,$(libfdt) $(libfdt_hdrs)): $(obj)/%: $(srctree)/scripts/dtc/libfdt/%

	$(call cmd,shipped)



$(addprefix $(obj)/,$(libfdt_objs) atags_to_fdt.o): \

	$(addprefix $(obj)/,$(libfdt_hdrs))

libfdt_objs := fdt_rw.o fdt_ro.o fdt_wip.o fdt.o



ifeq ($(CONFIG_ARM_ATAG_DTB_COMPAT),y)

OBJS	+= $(libfdt_objs) atags_to_fdt.o

endif



# -fstack-protector-strong triggers protection checks in this code,

# but it is being used too early to link to meaningful stack_chk logic.

nossp-flags-$(CONFIG_CC_HAS_STACKPROTECTOR_NONE) := -fno-stack-protector

$(foreach o, $(libfdt_objs) atags_to_fdt.o, \

	$(eval CFLAGS_$(o) := -I $(srctree)/scripts/dtc/libfdt $(nossp-flags-y)))



# These were previously generated C files. When you are building the kernel

# with O=, make sure to remove the stale files in the output tree. Otherwise,

# the build system wrongly compiles the stale ones.

ifdef building_out_of_srctree

$(shell rm -f $(addprefix $(obj)/, fdt_rw.c fdt_ro.c fdt_wip.c fdt.c))

endif



targets       := vmlinux vmlinux.lds piggy_data piggy.o \

		 lib1funcs.o ashldi3.o bswapsdi2.o \

		 head.o $(OBJS)



clean-files += piggy_data lib1funcs.S ashldi3.S bswapsdi2.S \

		$(libfdt) $(libfdt_hdrs) hyp-stub.S

clean-files += piggy_data lib1funcs.S ashldi3.S bswapsdi2.S hyp-stub.S



KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
@@ -107,15 +108,6 @@ ORIG_CFLAGS := $(KBUILD_CFLAGS) 
KBUILD_CFLAGS = $(subst -pg, , $(ORIG_CFLAGS))

endif



# -fstack-protector-strong triggers protection checks in this code,

# but it is being used too early to link to meaningful stack_chk logic.

nossp-flags-$(CONFIG_CC_HAS_STACKPROTECTOR_NONE) := -fno-stack-protector

CFLAGS_atags_to_fdt.o := $(nossp-flags-y)

CFLAGS_fdt.o := $(nossp-flags-y)

CFLAGS_fdt_ro.o := $(nossp-flags-y)

CFLAGS_fdt_rw.o := $(nossp-flags-y)

CFLAGS_fdt_wip.o := $(nossp-flags-y)



ccflags-y := -fpic $(call cc-option,-mno-single-pic-base,) -fno-builtin \

	     -I$(obj) $(DISABLE_ARM_SSP_PER_TASK_PLUGIN)

asflags-y := -DZIMAGE

arch/arm/boot/compressed/atags_to_fdt.c

+1 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

#include <linux/libfdt_env.h>

#include <asm/setup.h>

#include <libfdt.h>

arch/arm/boot/compressed/fdt.c

0 → 100644
+2 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

#include "../../../../lib/fdt.c"

arch/arm/boot/compressed/fdt_ro.c

0 → 100644
+2 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

#include "../../../../lib/fdt_ro.c"

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