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https://github.com/torvalds/linux
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b1992c3772
Kbuild conventionally uses $(obj)/ for generated files, and $(src)/ for
checked-in source files. It is merely a convention without any functional
difference. In fact, $(obj) and $(src) are exactly the same, as defined
in scripts/Makefile.build:
src := $(obj)
When the kernel is built in a separate output directory, $(src) does
not accurately reflect the source directory location. While Kbuild
resolves this discrepancy by specifying VPATH=$(srctree) to search for
source files, it does not cover all cases. For example, when adding a
header search path for local headers, -I$(srctree)/$(src) is typically
passed to the compiler.
This introduces inconsistency between upstream and downstream Makefiles
because $(src) is used instead of $(srctree)/$(src) for the latter.
To address this inconsistency, this commit changes the semantics of
$(src) so that it always points to the directory in the source tree.
Going forward, the variables used in Makefiles will have the following
meanings:
$(obj) - directory in the object tree
$(src) - directory in the source tree (changed by this commit)
$(objtree) - the top of the kernel object tree
$(srctree) - the top of the kernel source tree
Consequently, $(srctree)/$(src) in upstream Makefiles need to be replaced
with $(src).
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
86 lines
2.7 KiB
Makefile
86 lines
2.7 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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#
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# kbuild file for usr/ - including initramfs image
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#
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compress-y := copy
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compress-$(CONFIG_INITRAMFS_COMPRESSION_GZIP) := gzip
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compress-$(CONFIG_INITRAMFS_COMPRESSION_BZIP2) := bzip2
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compress-$(CONFIG_INITRAMFS_COMPRESSION_LZMA) := lzma
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compress-$(CONFIG_INITRAMFS_COMPRESSION_XZ) := xzmisc
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compress-$(CONFIG_INITRAMFS_COMPRESSION_LZO) := lzo
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compress-$(CONFIG_INITRAMFS_COMPRESSION_LZ4) := lz4
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compress-$(CONFIG_INITRAMFS_COMPRESSION_ZSTD) := zstd
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obj-$(CONFIG_BLK_DEV_INITRD) := initramfs_data.o
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$(obj)/initramfs_data.o: $(obj)/initramfs_inc_data
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ramfs-input := $(CONFIG_INITRAMFS_SOURCE)
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cpio-data :=
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# If CONFIG_INITRAMFS_SOURCE is empty, generate a small initramfs with the
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# default contents.
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ifeq ($(ramfs-input),)
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ramfs-input := $(src)/default_cpio_list
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endif
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ifeq ($(words $(ramfs-input)),1)
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# If CONFIG_INITRAMFS_SOURCE specifies a single file, and it is suffixed with
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# .cpio, use it directly as an initramfs.
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ifneq ($(filter %.cpio,$(ramfs-input)),)
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cpio-data := $(ramfs-input)
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endif
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# If CONFIG_INITRAMFS_SOURCE specifies a single file, and it is suffixed with
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# .cpio.*, use it directly as an initramfs, and avoid double compression.
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ifeq ($(words $(subst .cpio.,$(space),$(ramfs-input))),2)
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cpio-data := $(ramfs-input)
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compress-y := copy
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endif
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endif
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# For other cases, generate the initramfs cpio archive based on the contents
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# specified by CONFIG_INITRAMFS_SOURCE.
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ifeq ($(cpio-data),)
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cpio-data := $(obj)/initramfs_data.cpio
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hostprogs := gen_init_cpio
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# .initramfs_data.cpio.d is used to identify all files included
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# in initramfs and to detect if any files are added/removed.
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# Removed files are identified by directory timestamp being updated
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# The dependency list is generated by gen_initramfs.sh -l
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-include $(obj)/.initramfs_data.cpio.d
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# do not try to update files included in initramfs
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$(deps_initramfs): ;
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quiet_cmd_initfs = GEN $@
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cmd_initfs = \
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$(CONFIG_SHELL) $< -o $@ -l $(obj)/.initramfs_data.cpio.d \
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$(if $(CONFIG_INITRAMFS_ROOT_UID), -u $(CONFIG_INITRAMFS_ROOT_UID)) \
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$(if $(CONFIG_INITRAMFS_ROOT_GID), -g $(CONFIG_INITRAMFS_ROOT_GID)) \
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$(if $(KBUILD_BUILD_TIMESTAMP), -d "$(KBUILD_BUILD_TIMESTAMP)") \
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$(ramfs-input)
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# We rebuild initramfs_data.cpio if:
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# 1) Any included file is newer than initramfs_data.cpio
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# 2) There are changes in which files are included (added or deleted)
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# 3) If gen_init_cpio are newer than initramfs_data.cpio
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# 4) Arguments to gen_initramfs.sh changes
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$(obj)/initramfs_data.cpio: $(src)/gen_initramfs.sh $(obj)/gen_init_cpio $(deps_initramfs) FORCE
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$(call if_changed,initfs)
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endif
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$(obj)/initramfs_inc_data: $(cpio-data) FORCE
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$(call if_changed,$(compress-y))
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targets += initramfs_data.cpio initramfs_inc_data
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subdir-$(CONFIG_UAPI_HEADER_TEST) += include
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