Subject: [PATCH v2] ARM: decompressor: simplify libfdt builds

From: Masahiro Yamada <[email-masked]>
Date: Sun, 19 Jan 2020 10:08:22 +0900

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 that 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>.

Signed-off-by: Masahiro Yamada <[email-masked]>
---

KernelVersion: v5.5-rc1

Changes in v2:
  - fix build error

 arch/arm/boot/compressed/.gitignore     |  9 -------
 arch/arm/boot/compressed/Makefile       | 33 +++++++------------------
 arch/arm/boot/compressed/atags_to_fdt.c |  1 +
 arch/arm/boot/compressed/fdt.c          |  1 +
 arch/arm/boot/compressed/fdt_ro.c       |  1 +
 arch/arm/boot/compressed/fdt_rw.c       |  1 +
 arch/arm/boot/compressed/fdt_wip.c      |  1 +
 arch/arm/boot/compressed/libfdt_env.h   | 24 ------------------
 8 files changed, 14 insertions(+), 57 deletions(-)
 create mode 100644 arch/arm/boot/compressed/fdt.c
 create mode 100644 arch/arm/boot/compressed/fdt_ro.c
 create mode 100644 arch/arm/boot/compressed/fdt_rw.c
 create mode 100644 arch/arm/boot/compressed/fdt_wip.c
 delete mode 100644 arch/arm/boot/compressed/libfdt_env.h

diff --git a/arch/arm/boot/compressed/.gitignore b/arch/arm/boot/compressed/.gitignore
index 86b2f5d28240..2fdb4885846b 100644
--- a/arch/arm/boot/compressed/.gitignore
+++ b/arch/arm/boot/compressed/.gitignore
@@ -6,12 +6,3 @@ 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 da599c3a1193..07962a320b89 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -76,29 +76,23 @@ 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/%
-	$(call cmd,shipped)
+ifeq ($(CONFIG_ARM_ATAG_DTB_COMPAT),y)
+libfdt_objs = fdt_rw.o fdt_ro.o fdt_wip.o fdt.o atags_to_fdt.o
 
-$(addprefix $(obj)/,$(libfdt_objs) atags_to_fdt.o): \
-	$(addprefix $(obj)/,$(libfdt_hdrs))
+OBJS	+= $(libfdt_objs)
 
-ifeq ($(CONFIG_ARM_ATAG_DTB_COMPAT),y)
-OBJS	+= $(libfdt_objs) atags_to_fdt.o
+# -fstack-protector-strong triggers protection checks in this code,
+# but it is being used too early to link to meaningful stack_chk logic.
+nossp-flags-$(CONFIG_CC_HAS_STACKPROTECTOR_NONE) := -fno-stack-protector
+$(foreach o, $(libfdt_objs), \
+	$(eval CFLAGS_$(o) := -I $(srctree)/scripts/dtc/libfdt $(nossp-flags-y)))
 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
 KBUILD_CFLAGS += $(DISABLE_ARM_SSP_PER_TASK_PLUGIN)
@@ -108,15 +102,6 @@ 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)
 asflags-y := -DZIMAGE
 
diff --git a/arch/arm/boot/compressed/atags_to_fdt.c b/arch/arm/boot/compressed/atags_to_fdt.c
index 64c49747f8a3..8452753efebe 100644
--- 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
index 000000000000..49bc1fc1e273
--- /dev/null
+++ b/arch/arm/boot/compressed/fdt.c
@@ -0,0 +1 @@
+#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
index 000000000000..fc7f8313e93e
--- /dev/null
+++ b/arch/arm/boot/compressed/fdt_ro.c
@@ -0,0 +1 @@
+#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
index 000000000000..7e9777da2708
--- /dev/null
+++ b/arch/arm/boot/compressed/fdt_rw.c
@@ -0,0 +1 @@
+#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
index 000000000000..f0b580e760a7
--- /dev/null
+++ b/arch/arm/boot/compressed/fdt_wip.c
@@ -0,0 +1 @@
+#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
index 6a0f1f524466..000000000000
--- 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
-- 
2.17.1

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