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: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

diff --git a/arch/arm/boot/compressed/.gitignore b/arch/arm/boot/compressed/.gitignore
index db05c6ef3e31325521475447818ddca0d8f35341..60606b0f378d59e80880e9a3ad01ff6f53ed5174 100644 (file)
--- a/arch/arm/boot/compressed/.gitignore
+++ b/arch/arm/boot/compressed/.gitignore
@@ -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

diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index 9c11e7490292f0e0031b2dfb4f7e0386b3bcee38..00602a6fba04733ffb9aa64dbf0022e5469db8b9 100644 (file)
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -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

diff --git a/arch/arm/boot/compressed/atags_to_fdt.c b/arch/arm/boot/compressed/atags_to_fdt.c
index 64c49747f8a3108f6638e300f16df19b7be68d12..8452753efebe5621e2569db95df2b4c30b26df99 100644 (file)
--- a/arch/arm/boot/compressed/atags_to_fdt.c
+++ b/arch/arm/boot/compressed/atags_to_fdt.c
@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0
+#include <linux/libfdt_env.h>
 #include <asm/setup.h>
 #include <libfdt.h>
 

diff --git a/arch/arm/boot/compressed/fdt.c b/arch/arm/boot/compressed/fdt.c
new file mode 100644 (file)
index 0000000..f8ea7a2
--- /dev/null
+++ b/arch/arm/boot/compressed/fdt.c
@@ -0,0 +1,2 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include "../../../../lib/fdt.c"

diff --git a/arch/arm/boot/compressed/fdt_ro.c b/arch/arm/boot/compressed/fdt_ro.c
new file mode 100644 (file)
index 0000000..93970a4
--- /dev/null
+++ b/arch/arm/boot/compressed/fdt_ro.c
@@ -0,0 +1,2 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include "../../../../lib/fdt_ro.c"

diff --git a/arch/arm/boot/compressed/fdt_rw.c b/arch/arm/boot/compressed/fdt_rw.c
new file mode 100644 (file)
index 0000000..f7c6b8b
--- /dev/null
+++ b/arch/arm/boot/compressed/fdt_rw.c
@@ -0,0 +1,2 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include "../../../../lib/fdt_rw.c"

diff --git a/arch/arm/boot/compressed/fdt_wip.c b/arch/arm/boot/compressed/fdt_wip.c
new file mode 100644 (file)
index 0000000..048d2c7
--- /dev/null
+++ b/arch/arm/boot/compressed/fdt_wip.c
@@ -0,0 +1,2 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include "../../../../lib/fdt_wip.c"

diff --git a/arch/arm/boot/compressed/libfdt_env.h b/arch/arm/boot/compressed/libfdt_env.h
deleted file mode 100644 (file)
index 6a0f1f5..0000000
--- a/arch/arm/boot/compressed/libfdt_env.h
+++ /dev/null
@@ -1,24 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ARM_LIBFDT_ENV_H
-#define _ARM_LIBFDT_ENV_H
-
-#include <linux/limits.h>
-#include <linux/types.h>
-#include <linux/string.h>
-#include <asm/byteorder.h>
-
-#define INT32_MAX      S32_MAX
-#define UINT32_MAX     U32_MAX
-
-typedef __be16 fdt16_t;
-typedef __be32 fdt32_t;
-typedef __be64 fdt64_t;
-
-#define fdt16_to_cpu(x)                be16_to_cpu(x)
-#define cpu_to_fdt16(x)                cpu_to_be16(x)
-#define fdt32_to_cpu(x)                be32_to_cpu(x)
-#define cpu_to_fdt32(x)                cpu_to_be32(x)
-#define fdt64_to_cpu(x)                be64_to_cpu(x)
-#define cpu_to_fdt64(x)                cpu_to_be64(x)
-
-#endif