[PATCH v2 16/16] riscv: boot: add Image.xz support

Lasse Collin
2024-07-21T13:37:23Z

The Image.* targets existed for other compressors already. Bootloader
support is needed for decompression.

This is for CONFIG_EFI_ZBOOT=n. With CONFIG_EFI_ZBOOT=y, XZ was already
available.

Comparision with Linux 6.10 RV64GC tinyconfig (in KiB):

1027 Image
594 Image.gz
541 Image.zst
510 Image.lzma
474 Image.xz

Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Jules Maselbas <jmaselbas@zdiv.net>
Cc: linux-riscv@lists.infradead.org
Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
---
arch/riscv/Kconfig | 1 +
arch/riscv/Makefile | 6 ++++--
arch/riscv/boot/Makefile | 3 +++
3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 736457a5898a..ef6a603b80c5 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -153,6 +153,7 @@ config RISCV
select HAVE_KERNEL_LZO if !XIP_KERNEL && !EFI_ZBOOT
select HAVE_KERNEL_UNCOMPRESSED if !XIP_KERNEL && !EFI_ZBOOT
select HAVE_KERNEL_ZSTD if !XIP_KERNEL && !EFI_ZBOOT
+ select HAVE_KERNEL_XZ if !XIP_KERNEL && !EFI_ZBOOT
select HAVE_KPROBES if !XIP_KERNEL
select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL
select HAVE_KRETPROBES if !XIP_KERNEL
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 6fe682139d2e..d469db9f46f4 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -159,6 +159,7 @@ boot-image-$(CONFIG_KERNEL_LZ4) := Image.lz4
boot-image-$(CONFIG_KERNEL_LZMA) := Image.lzma
boot-image-$(CONFIG_KERNEL_LZO) := Image.lzo
boot-image-$(CONFIG_KERNEL_ZSTD) := Image.zst
+boot-image-$(CONFIG_KERNEL_XZ) := Image.xz
ifdef CONFIG_RISCV_M_MODE
boot-image-$(CONFIG_ARCH_CANAAN) := loader.bin
endif
@@ -183,12 +184,12 @@ endif
vdso-install-y += arch/riscv/kernel/vdso/vdso.so.dbg
vdso-install-$(CONFIG_COMPAT) += arch/riscv/kernel/compat_vdso/compat_vdso.so.dbg

-BOOT_TARGETS := Image Image.gz Image.bz2 Image.lz4 Image.lzma Image.lzo Image.zst loader loader.bin xipImage vmlinuz.efi
+BOOT_TARGETS := Image Image.gz Image.bz2 Image.lz4 Image.lzma Image.lzo Image.zst Image.xz loader loader.bin xipImage vmlinuz.efi

all: $(notdir $(KBUILD_IMAGE))

loader.bin: loader
-Image.gz Image.bz2 Image.lz4 Image.lzma Image.lzo Image.zst loader xipImage vmlinuz.efi: Image
+Image.gz Image.bz2 Image.lz4 Image.lzma Image.lzo Image.zst Image.xz loader xipImage vmlinuz.efi: Image

$(BOOT_TARGETS): vmlinux
$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
@@ -225,6 +226,7 @@ define archhelp
echo ' Image.lzma - Compressed kernel image (arch/riscv/boot/Image.lzma)'
echo ' Image.lzo - Compressed kernel image (arch/riscv/boot/Image.lzo)'
echo ' Image.zst - Compressed kernel image (arch/riscv/boot/Image.zst)'
+ echo ' Image.xz - Compressed kernel image (arch/riscv/boot/Image.xz)'
echo ' vmlinuz.efi - Compressed EFI kernel image (arch/riscv/boot/vmlinuz.efi)'
echo ' Default when CONFIG_EFI_ZBOOT=y'
echo ' xipImage - Execute-in-place kernel image (arch/riscv/boot/xipImage)'
diff --git a/arch/riscv/boot/Makefile b/arch/riscv/boot/Makefile
index 869c0345b908..710a5f6caf96 100644
--- a/arch/riscv/boot/Makefile
+++ b/arch/riscv/boot/Makefile
@@ -65,6 +65,9 @@ $(obj)/Image.lzo: $(obj)/Image FORCE
$(obj)/Image.zst: $(obj)/Image FORCE
$(call if_changed,zstd)

+$(obj)/Image.xz: $(obj)/Image FORCE
+ $(call if_changed,xzkern)
+
$(obj)/loader.bin: $(obj)/loader FORCE
$(call if_changed,objcopy)

--
2.45.2