[PATCH v2 12/13] initramfs: refactor the initramfs build rules

From: Masahiro Yamada
Date: Sat Jan 04 2020 - 10:04:00 EST

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Currently, usr/gen_initramfs.sh takes care of all the use-cases:

[1] generates a cpio file unless CONFIG_INITRAMFS_SOURCE points to
a single cpio archive

[2] If CONFIG_INITRAMFS_SOURCE is the path to a cpio archive,
use it as-is.

[3] Compress the cpio file according to CONFIG_INITRAMFS_COMPRESSION_*
unless it is passed a compressed archive.

To simplify the script, move [2] and [3] to usr/Makefile.

If CONFIG_INITRAMFS_SOURCE is the path to a cpio archive, there is
no need to run this shell script.

For the cpio archive compression, you can re-use the rules from
scripts/Makefile.lib .

Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
---

Changes in v2:
- improve the comments so that they match to the code
- use $(strip ...) instead of $(words ...)
for the case CONFIG_INITRAMFS_SOURCE is empty

usr/.gitignore | 8 +---
usr/Kconfig | 10 -----
usr/Makefile | 89 +++++++++++++++++++++++++++++---------------
usr/gen_initramfs.sh | 77 ++++++++------------------------------
usr/initramfs_data.S | 5 +--
5 files changed, 78 insertions(+), 111 deletions(-)

diff --git a/usr/.gitignore b/usr/.gitignore
index be5eae1df7eb..610de736b75e 100644
--- a/usr/.gitignore
+++ b/usr/.gitignore
@@ -1,9 +1,3 @@
-#
-# Generated files
-#
gen_init_cpio
initramfs_data.cpio
-initramfs_data.cpio.gz
-initramfs_data.cpio.bz2
-initramfs_data.cpio.lzma
-initramfs_list
+/initramfs_inc_data
diff --git a/usr/Kconfig b/usr/Kconfig
index ab61e81165e0..529caab1a328 100644
--- a/usr/Kconfig
+++ b/usr/Kconfig
@@ -207,13 +207,3 @@ config INITRAMFS_COMPRESSION_LZ4
by default which could cause a build failure.

endchoice
-
-config INITRAMFS_COMPRESSION
- string
- default "" if INITRAMFS_COMPRESSION_NONE
- default ".gz" if INITRAMFS_COMPRESSION_GZIP
- default ".bz2" if INITRAMFS_COMPRESSION_BZIP2
- default ".lzma" if INITRAMFS_COMPRESSION_LZMA
- default ".xz" if INITRAMFS_COMPRESSION_XZ
- default ".lzo" if INITRAMFS_COMPRESSION_LZO
- default ".lz4" if INITRAMFS_COMPRESSION_LZ4
diff --git a/usr/Makefile b/usr/Makefile
index 9256a5b189ee..e03753888ad4 100644
--- a/usr/Makefile
+++ b/usr/Makefile
@@ -3,55 +3,86 @@
# kbuild file for usr/ - including initramfs image
#

-suffix_y = $(subst $\",,$(CONFIG_INITRAMFS_COMPRESSION))
-datafile_y = initramfs_data.cpio$(suffix_y)
-datafile_d_y = .$(datafile_y).d
-AFLAGS_initramfs_data.o += -DINITRAMFS_IMAGE="usr/$(datafile_y)"
+# cmd_bzip2, cmd_lzma, cmd_lzo, cmd_lz4 from scripts/Makefile.lib appends the
+# size at the end of the compressed file, which unfortunately does not work
+# with unpack_to_rootfs(). Make size_append no-op.
+override size_append := :

-# clean rules do not have CONFIG_INITRAMFS_COMPRESSION. So clean up after all
-# possible compression formats.
-clean-files += initramfs_data.cpio*
+compress-$(CONFIG_INITRAMFS_COMPRESSION_NONE) := shipped
+compress-$(CONFIG_INITRAMFS_COMPRESSION_GZIP) := gzip
+compress-$(CONFIG_INITRAMFS_COMPRESSION_BZIP2) := bzip2
+compress-$(CONFIG_INITRAMFS_COMPRESSION_LZMA) := lzma
+compress-$(CONFIG_INITRAMFS_COMPRESSION_XZ) := xzmisc
+compress-$(CONFIG_INITRAMFS_COMPRESSION_LZO) := lzo
+compress-$(CONFIG_INITRAMFS_COMPRESSION_LZ4) := lz4

-# Generate builtin.o based on initramfs_data.o
obj-$(CONFIG_BLK_DEV_INITRD) := initramfs_data.o

-# initramfs_data.o contains the compressed initramfs_data.cpio image.
-# The image is included using .incbin, a dependency which is not
-# tracked automatically.
-$(obj)/initramfs_data.o: $(obj)/$(datafile_y) FORCE
+$(obj)/initramfs_data.o: $(obj)/initramfs_inc_data

-#####
-# Generate the initramfs cpio archive
+ramfs-input := $(strip $(shell echo $(CONFIG_INITRAMFS_SOURCE)))
+cpio-data :=
+
+# If CONFIG_INITRAMFS_SOURCE is empty, generate a small initramfs with the
+# default contents.
+ifeq ($(ramfs-input),)
+ramfs-input := $(srctree)/$(src)/default_cpio_list
+endif
+
+ifeq ($(words $(ramfs-input)),1)
+
+# If CONFIG_INITRAMFS_SOURCE specifies a single file, and it is suffixed with
+# .cpio, use it directly as an initramfs.
+ifneq ($(filter %.cpio,$(ramfs-input)),)
+cpio-data := $(ramfs-input)
+endif
+
+# If CONFIG_INITRAMFS_SOURCE specifies a single file, and it is suffixed with
+# .cpio.*, use it directly as an initramfs, and avoid double compression.
+ifeq ($(words $(subst .cpio.,$(space),$(ramfs-input))),2)
+cpio-data := $(ramfs-input)
+compress-y := shipped
+endif
+
+endif
+
+# For other cases, generate the initramfs cpio archive based on the contents
+# specified by CONFIG_INITRAMFS_SOURCE.
+ifeq ($(cpio-data),)
+
+cpio-data := $(obj)/initramfs_data.cpio

hostprogs-y := gen_init_cpio
-ramfs-input := $(if $(filter-out "",$(CONFIG_INITRAMFS_SOURCE)), \
- $(shell echo $(CONFIG_INITRAMFS_SOURCE)),$(srctree)/$(src)/default_cpio_list)
-ramfs-args := \
- $(if $(CONFIG_INITRAMFS_ROOT_UID), -u $(CONFIG_INITRAMFS_ROOT_UID)) \
- $(if $(CONFIG_INITRAMFS_ROOT_GID), -g $(CONFIG_INITRAMFS_ROOT_GID))

-# $(datafile_d_y) is used to identify all files included
+# .initramfs_data.cpio.d is used to identify all files included
# in initramfs and to detect if any files are added/removed.
# Removed files are identified by directory timestamp being updated
# The dependency list is generated by gen_initramfs.sh -l
-ifneq ($(wildcard $(obj)/$(datafile_d_y)),)
- include $(obj)/$(datafile_d_y)
-endif
-
-quiet_cmd_initfs = GEN $@
- cmd_initfs = $< -o $@ -l $(obj)/$(datafile_d_y) $(ramfs-args) $(ramfs-input)
-
-targets := $(datafile_y)
+-include $(obj)/.initramfs_data.cpio.d

# do not try to update files included in initramfs
$(deps_initramfs): ;

+quiet_cmd_initfs = GEN $@
+ cmd_initfs = \
+ $< -o $@ -l $(obj)/.initramfs_data.cpio.d \
+ $(if $(CONFIG_INITRAMFS_ROOT_UID), -u $(CONFIG_INITRAMFS_ROOT_UID)) \
+ $(if $(CONFIG_INITRAMFS_ROOT_GID), -g $(CONFIG_INITRAMFS_ROOT_GID)) \
+ $(ramfs-input)
+
# We rebuild initramfs_data.cpio if:
# 1) Any included file is newer than initramfs_data.cpio
# 2) There are changes in which files are included (added or deleted)
# 3) If gen_init_cpio are newer than initramfs_data.cpio
# 4) Arguments to gen_initramfs.sh changes
-$(obj)/$(datafile_y): $(src)/gen_initramfs.sh $(obj)/gen_init_cpio $(deps_initramfs) FORCE
+$(obj)/initramfs_data.cpio: $(src)/gen_initramfs.sh $(obj)/gen_init_cpio $(deps_initramfs) FORCE
$(call if_changed,initfs)

+endif
+
+$(obj)/initramfs_inc_data: $(cpio-data) FORCE
+ $(call if_changed,$(compress-y))
+
+targets += initramfs_data.cpio initramfs_inc_data
+
subdir-$(CONFIG_UAPI_HEADER_TEST) += include
diff --git a/usr/gen_initramfs.sh b/usr/gen_initramfs.sh
index 1efb87bda545..4e6715f8ff7f 100755
--- a/usr/gen_initramfs.sh
+++ b/usr/gen_initramfs.sh
@@ -5,7 +5,7 @@
# Released under the terms of the GNU GPL
#
# Generate a cpio packed initramfs. It uses gen_init_cpio to generate
-# the cpio archive, and then compresses it.
+# the cpio archive.
# This script assumes that gen_init_cpio is located in usr/ directory

# error out on errors
@@ -15,8 +15,7 @@ usage() {
cat << EOF
Usage:
$0 [-o <file>] [-l <dep_list>] [-u <uid>] [-g <gid>] {-d | <cpio_source>} ...
- -o <file> Create compressed initramfs file named <file> using
- gen_init_cpio and compressor depending on the extension
+ -o <file> Create initramfs file named <file> by using gen_init_cpio
-l <dep_list> Create dependency list named <dep_list>
-u <uid> User ID to map to user ID 0 (root).
<uid> is only meaningful if <cpio_source> is a
@@ -162,20 +161,12 @@ dir_filelist() {
fi
}

-# if only one file is specified and it is .cpio file then use it direct as fs
-# if a directory is specified then add all files in given direcotry to fs
-# if a regular file is specified assume it is in gen_init_cpio format
input_file() {
source="$1"
if [ -f "$1" ]; then
+ # If a regular file is specified, assume it is in
+ # gen_init_cpio format
header "$1"
- is_cpio="$(echo "$1" | sed 's/^.*\.cpio$\..*$\{0,1\}/cpio/')"
- if [ $2 -eq 0 -a ${is_cpio} = "cpio" ]; then
- cpio_file=$1
- echo "$1" | grep -q '^.*\.cpio\..*' && is_cpio_compressed="compressed"
- [ -n "$dep_list" ] && echo "$1" >> $dep_list
- return 0
- fi
print_mtime "$1" >> $cpio_list
cat "$1" >> $cpio_list
if [ -n "$dep_list" ]; then
@@ -187,6 +178,7 @@ input_file() {
done
fi
elif [ -d "$1" ]; then
+ # If a directory is specified then add all files in it to fs
dir_filelist "$1"
else
echo " ${prog}: Cannot open '$1'" >&2
@@ -198,12 +190,8 @@ prog=$0
root_uid=0
root_gid=0
dep_list=
-cpio_file=
cpio_list=$(mktemp ${TMPDIR:-/tmp}/cpiolist.XXXXXX)
output="/dev/stdout"
-output_file="/dev/stdout"
-is_cpio_compressed=
-compr="gzip -n -9 -f"

while [ $# -gt 0 ]; do
arg="$1"
@@ -214,28 +202,8 @@ while [ $# -gt 0 ]; do
echo "deps_initramfs := \\" > $dep_list
shift
;;
- "-o") # generate compressed cpio image named $1
- output_file="$1"
- output=$cpio_list
- echo "$output_file" | grep -q "\.gz$" \
- && [ -x "`which gzip 2> /dev/null`" ] \
- && compr="gzip -n -9 -f"
- echo "$output_file" | grep -q "\.bz2$" \
- && [ -x "`which bzip2 2> /dev/null`" ] \
- && compr="bzip2 -9 -f"
- echo "$output_file" | grep -q "\.lzma$" \
- && [ -x "`which lzma 2> /dev/null`" ] \
- && compr="lzma -9 -f"
- echo "$output_file" | grep -q "\.xz$" \
- && [ -x "`which xz 2> /dev/null`" ] \
- && compr="xz --check=crc32 --lzma2=dict=1MiB"
- echo "$output_file" | grep -q "\.lzo$" \
- && [ -x "`which lzop 2> /dev/null`" ] \
- && compr="lzop -9 -f"
- echo "$output_file" | grep -q "\.lz4$" \
- && [ -x "`which lz4 2> /dev/null`" ] \
- && compr="lz4 -l -9 -f"
- echo "$output_file" | grep -q "\.cpio$" && compr="cat"
+ "-o") # generate cpio image named $1
+ output="$1"
shift
;;
"-u") # map $1 to uid=0 (root)
@@ -258,34 +226,21 @@ while [ $# -gt 0 ]; do
unknown_option
;;
*) # input file/dir - process it
- input_file "$arg" "$#"
+ input_file "$arg"
;;
esac
;;
esac
done

-# If output_file is set we will generate cpio archive and compress it
+# If output_file is set we will generate cpio archive
# we are careful to delete tmp files
-if [ -z ${cpio_file} ]; then
- timestamp=
- if test -n "$KBUILD_BUILD_TIMESTAMP"; then
- timestamp="$(date -d"$KBUILD_BUILD_TIMESTAMP" +%s || :)"
- if test -n "$timestamp"; then
- timestamp="-t $timestamp"
- fi
+timestamp=
+if test -n "$KBUILD_BUILD_TIMESTAMP"; then
+ timestamp="$(date -d"$KBUILD_BUILD_TIMESTAMP" +%s || :)"
+ if test -n "$timestamp"; then
+ timestamp="-t $timestamp"
fi
- cpio_tfile="$(mktemp ${TMPDIR:-/tmp}/cpiofile.XXXXXX)"
- usr/gen_init_cpio $timestamp ${cpio_list} > ${cpio_tfile}
-else
- cpio_tfile=${cpio_file}
-fi
-rm ${cpio_list}
-if [ "${is_cpio_compressed}" = "compressed" ]; then
- cat ${cpio_tfile} > ${output_file}
-else
- (cat ${cpio_tfile} | ${compr} - > ${output_file}) \
- || (rm -f ${output_file} ; false)
fi
-[ -z ${cpio_file} ] && rm ${cpio_tfile}
-exit 0
+usr/gen_init_cpio $timestamp $cpio_list > $output
+rm $cpio_list
diff --git a/usr/initramfs_data.S b/usr/initramfs_data.S
index d07648f05bbf..cd67edc38797 100644
--- a/usr/initramfs_data.S
+++ b/usr/initramfs_data.S
@@ -22,12 +22,9 @@
in the ELF header, as required by certain architectures.
*/

-#include <linux/stringify.h>
-#include <asm-generic/vmlinux.lds.h>
-
.section .init.ramfs,"a"
__irf_start:
-.incbin __stringify(INITRAMFS_IMAGE)
+.incbin "usr/initramfs_inc_data"
__irf_end:
.section .init.ramfs.info,"a"
.globl __initramfs_size
--
2.17.1

Next message: Masahiro Yamada: "[PATCH v2 08/13] initramfs: specify $(src)/gen_initramfs.sh as a prerequisite in Makefile"
Previous message: Masahiro Yamada: "[PATCH v2 10/13] initramfs: add default_cpio_list, and delete -d option support"
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