kernel: build the separate initramfs kernel only once

With TARGET_ROOTFS_INITRAMFS_SEPARATE, the initramfs kernel differs
from the regular kernel only in CONFIG_RD_<ALGO>. Both are built in the
same tree, so every build switches the kernel config twice and relinks
vmlinux twice, even if nothing changed.

Give the regular kernel the same ramdisk support and use its image for
the initramfs as is. The initramfs step now only creates the initrd.
Remove the separate initramfs branches of Kernel/SetInitramfs, as it is
no longer called in this mode.

Signed-off-by: John Crispin <john@phrozen.org>
This commit is contained in:
John Crispin committed 2026-09-22 18:18:58 +02:00
1 parent b95b0928ac
commit 714886f3e4
1 file changed
+31 -31
+31 -31
View File
@@ -45,31 +45,21 @@ else
endif
ifeq ($(CONFIG_TARGET_ROOTFS_INITRAMFS),y)
ifeq ($(CONFIG_TARGET_ROOTFS_INITRAMFS_SEPARATE),y)
ifeq ($(strip $(CONFIG_EXTERNAL_CPIO)),"")
define Kernel/SetInitramfs/PreConfigure
{ \
grep -v -e CONFIG_BLK_DEV_INITRD $(2)/.config.old > $(2)/.config; \
echo 'CONFIG_BLK_DEV_INITRD=y' >> $(2)/.config; \
echo 'CONFIG_INITRAMFS_SOURCE=""' >> $(2)/.config; \
}
endef
else
ifeq ($(strip $(CONFIG_EXTERNAL_CPIO)),"")
define Kernel/SetInitramfs/PreConfigure
{ \
grep -v -e INITRAMFS -e CONFIG_RD_ -e CONFIG_BLK_DEV_INITRD $(2)/.config.old > $(2)/.config; \
echo 'CONFIG_BLK_DEV_INITRD=y' >> $(2)/.config; \
echo 'CONFIG_INITRAMFS_SOURCE="$(strip $(1) $(INITRAMFS_EXTRA_FILES))"' >> $(2)/.config; \
}
endef
else
define Kernel/SetInitramfs/PreConfigure
endef
else
define Kernel/SetInitramfs/PreConfigure
{ \
grep -v INITRAMFS $(2)/.config.old > $(2)/.config; \
echo 'CONFIG_INITRAMFS_SOURCE="$(call qstrip,$(CONFIG_EXTERNAL_CPIO))"' >> $(2)/.config; \
}
endef
endif
endef
endif
define Kernel/SetInitramfs
@@ -78,13 +68,11 @@ ifeq ($(CONFIG_TARGET_ROOTFS_INITRAMFS),y)
mv $(2)/.config $(2)/.config.old; \
$(call Kernel/SetInitramfs/PreConfigure,$(1),$(2)); \
echo "# CONFIG_INITRAMFS_PRESERVE_MTIME is not set" >> $(2)/.config; \
$(if $(CONFIG_TARGET_ROOTFS_INITRAMFS_SEPARATE),,echo "CONFIG_INITRAMFS_ROOT_UID=$(shell id -u)" >> $(2)/.config;) \
$(if $(CONFIG_TARGET_ROOTFS_INITRAMFS_SEPARATE),,echo "CONFIG_INITRAMFS_ROOT_GID=$(shell id -g)" >> $(2)/.config;) \
$(if $(CONFIG_TARGET_ROOTFS_INITRAMFS_SEPARATE), \
echo "# CONFIG_INITRAMFS_FORCE is not set" >> $(2)/.config;, \
$(if $(CONFIG_TARGET_INITRAMFS_FORCE), \
echo "CONFIG_INITRAMFS_FORCE=y" >> $(2)/.config;, \
echo "# CONFIG_INITRAMFS_FORCE is not set" >> $(2)/.config;)) \
echo "CONFIG_INITRAMFS_ROOT_UID=$(shell id -u)" >> $(2)/.config; \
echo "CONFIG_INITRAMFS_ROOT_GID=$(shell id -g)" >> $(2)/.config; \
$(if $(CONFIG_TARGET_INITRAMFS_FORCE), \
echo "CONFIG_INITRAMFS_FORCE=y" >> $(2)/.config;, \
echo "# CONFIG_INITRAMFS_FORCE is not set" >> $(2)/.config;) \
$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_NONE), \
echo "CONFIG_INITRAMFS_COMPRESSION_NONE=y" >> $(2)/.config;, \
echo "# CONFIG_INITRAMFS_COMPRESSION_NONE is not set" >> $(2)/.config; ) \
@@ -92,21 +80,33 @@ ifeq ($(CONFIG_TARGET_ROOTFS_INITRAMFS),y)
$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_$(ALGO)), \
echo "CONFIG_INITRAMFS_COMPRESSION_$(ALGO)=y" >> $(2)/.config; $\, \
echo "# CONFIG_INITRAMFS_COMPRESSION_$(ALGO) is not set" >> $(2)/.config; $\) \
$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_$(ALGO)), \
echo "CONFIG_RD_$(ALGO)=y" >> $(2)/.config; $\, \
echo "# CONFIG_RD_$(ALGO) is not set" >> $(2)/.config; $\) \
) \
$(call Kernel/SetRamdiskCompression,$(2)/.config) \
}
endef
else
endif
define Kernel/SetRamdiskCompression
$(foreach ALGO,GZIP BZIP2 LZMA LZO XZ LZ4 ZSTD, \
$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_$(ALGO)), \
echo "CONFIG_RD_$(ALGO)=y" >> $(1); $\, \
echo "# CONFIG_RD_$(ALGO) is not set" >> $(1); $\) \
)
endef
# With a separate initramfs, the initramfs kernel differs from the regular
# kernel only in ramdisk support. Enable it here too, so that one kernel
# build serves both images.
define Kernel/SetNoInitramfs
mv $(LINUX_DIR)/.config.set $(LINUX_DIR)/.config.old
grep -v INITRAMFS $(LINUX_DIR)/.config.old > $(LINUX_DIR)/.config.set
echo 'CONFIG_INITRAMFS_SOURCE=""' >> $(LINUX_DIR)/.config.set
echo '# CONFIG_INITRAMFS_FORCE is not set' >> $(LINUX_DIR)/.config.set
echo "# CONFIG_INITRAMFS_PRESERVE_MTIME is not set" >> $(LINUX_DIR)/.config.set
$(if $(CONFIG_TARGET_ROOTFS_INITRAMFS_SEPARATE), \
echo 'CONFIG_BLK_DEV_INITRD=y' >> $(LINUX_DIR)/.config.set; \
$(call Kernel/SetRamdiskCompression,$(LINUX_DIR)/.config.set))
endef
define Kernel/Configure/Default
@@ -180,15 +180,16 @@ endef
ifneq ($(CONFIG_TARGET_ROOTFS_INITRAMFS),)
# $1: Custom TARGET_DIR. If omitted TARGET_DIR is used.
# $2: If defined Generate Per Rootfs Kernel Directory and use it
# For Separate Initramf with $2 declared, skip kernel compile, it has
# already been done previously on generic image build
# For Separate Initramfs, the regular kernel is used as is, as its config
# already has the ramdisk support (see Kernel/SetNoInitramfs)
define Kernel/CompileImage/Initramfs
$(call locked,{ \
$(if $(2),$(call Kernel/PrepareConfigPerRootfs,$(LINUX_DIR)$(2));) \
$(call Kernel/Configure/Initramfs,$(if $(1),$(1),$(TARGET_DIR)),$(LINUX_DIR)$(2)); \
$(if $(CONFIG_TARGET_ROOTFS_INITRAMFS_SEPARATE),, \
$(call Kernel/Configure/Initramfs,$(if $(1),$(1),$(TARGET_DIR)),$(LINUX_DIR)$(2)); \
rm -rf $(LINUX_DIR)$(2)/usr/initramfs_data.cpio*;) \
$(CP) $(GENERIC_PLATFORM_DIR)/other-files/init $(if $(1),$(1),$(TARGET_DIR))/init; \
$(if $(SOURCE_DATE_EPOCH),touch -hcd "@$(SOURCE_DATE_EPOCH)" $(if $(1),$(1),$(TARGET_DIR)) $(if $(1),$(1),$(TARGET_DIR))/init;) \
rm -rf $(LINUX_DIR)$(2)/usr/initramfs_data.cpio*; \
$(if $(CONFIG_TARGET_ROOTFS_INITRAMFS_SEPARATE), \
$(call locked,{ \
$(if $(call qstrip,$(CONFIG_EXTERNAL_CPIO)), \
@@ -210,8 +211,7 @@ define Kernel/CompileImage/Initramfs
$(STAGING_DIR_HOST)/bin/xz -T$(if $(filter 1,$(NPROC)),2,0) -9 -fz --check=crc32 $(KERNEL_BUILD_DIR)/initrd$(2).cpio;) \
$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_ZSTD), \
$(STAGING_DIR_HOST)/bin/zstd -T0 -f -o $(KERNEL_BUILD_DIR)/initrd$(2).cpio.zstd $(KERNEL_BUILD_DIR)/initrd$(2).cpio;) \
}, gen-cpio$(2)); \
$(if $(2),,$(KERNEL_MAKE) $(KERNEL_MAKEOPTS_IMAGE) $(if $(KERNELNAME),$(KERNELNAME),all);),\
}, gen-cpio$(2));,\
$(KERNEL_MAKE) $(if $(2),-C $(LINUX_DIR)$(2)) $(KERNEL_MAKEOPTS_IMAGE) $(if $(KERNELNAME),$(KERNELNAME),all);) \
$(call Kernel/CopyImage,-initramfs,$(2)); \
$(if $(2),rm -rf $(LINUX_DIR)$(2);) \