riscv: make image compression configurable

Previously the build process would always set KBUILD_IMAGE to the
uncompressed Image file (unless XIP_KERNEL or EFI_ZBOOT was enabled) and
unconditionally compress it into Image.gz. However there are already
build targets for Image.bz2, Image.lz4, Image.lzma, Image.lzo and
Image.zstd, so let's make use of those, make the compression method
configurable and set KBUILD_IMAGE accordingly so that targets like
'make install' and 'make bindeb-pkg' will use the chosen image.
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Signed-off-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20240504193446.196886-2-emil.renner.berthing@canonical.comSigned-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/Kconfig

@@ -140,6 +140,13 @@ config RISCV
 	select HAVE_GCC_PLUGINS
 	select HAVE_GENERIC_VDSO if MMU && 64BIT
 	select HAVE_IRQ_TIME_ACCOUNTING
+	select HAVE_KERNEL_BZIP2 if !XIP_KERNEL && !EFI_ZBOOT
+	select HAVE_KERNEL_GZIP if !XIP_KERNEL && !EFI_ZBOOT
+	select HAVE_KERNEL_LZ4 if !XIP_KERNEL && !EFI_ZBOOT
+	select HAVE_KERNEL_LZMA if !XIP_KERNEL && !EFI_ZBOOT
+	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_KPROBES if !XIP_KERNEL
 	select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL
 	select HAVE_KRETPROBES if !XIP_KERNEL

arch/riscv/Makefile

@@ -151,6 +151,21 @@ endif
 endif
 endif
 
+boot					:= arch/riscv/boot
+boot-image-y				:= Image
+boot-image-$(CONFIG_KERNEL_BZIP2)	:= Image.bz2
+boot-image-$(CONFIG_KERNEL_GZIP)	:= Image.gz
+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
+ifdef CONFIG_RISCV_M_MODE
+boot-image-$(CONFIG_ARCH_CANAAN)	:= loader.bin
+endif
+boot-image-$(CONFIG_EFI_ZBOOT)		:= vmlinuz.efi
+boot-image-$(CONFIG_XIP_KERNEL)		:= xipImage
+KBUILD_IMAGE				:= $(boot)/$(boot-image-y)
+
 libs-y += arch/riscv/lib/
 libs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a
 
@@ -168,21 +183,19 @@ 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 loader loader.bin xipImage vmlinuz.efi
+BOOT_TARGETS := Image Image.gz Image.bz2 Image.lz4 Image.lzma Image.lzo Image.zst loader loader.bin xipImage vmlinuz.efi
 
 all:	$(notdir $(KBUILD_IMAGE))
 
 loader.bin: loader
-Image.gz loader vmlinuz.efi: Image
+Image.gz Image.bz2 Image.lz4 Image.lzma Image.lzo Image.zst loader xipImage vmlinuz.efi: Image
+
 $(BOOT_TARGETS): vmlinux
 	$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
 	@$(kecho) '  Kernel: $(boot)/$@ is ready'
 
-Image.%: Image
-	$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
-
-install: KBUILD_IMAGE := $(boot)/Image
-zinstall: KBUILD_IMAGE := $(boot)/Image.gz
+# the install target always installs KBUILD_IMAGE (which may be compressed)
+# but keep the zinstall target for compatibility with older releases
 install zinstall:
 	$(call cmd,install)
 

arch/riscv/boot/install.sh

@@ -17,15 +17,18 @@
 #   $3 - kernel map file
 #   $4 - default install path (blank if root directory)
 
-if [ "$(basename $2)" = "Image.gz" ]; then
+case "${2##*/}" in
 # Compressed install
+Image.*|vmlinuz.efi)
   echo "Installing compressed kernel"
   base=vmlinuz
-else
+  ;;
 # Normal install
+*)
   echo "Installing normal kernel"
   base=vmlinux
-fi
+  ;;
+esac
 
 if [ -f $4/$base-$1 ]; then
   mv $4/$base-$1 $4/$base-$1.old