[PATCH 3/5] kbuild: rename cmd_{bzip2,lzma,lzo,lz4,xzkern,zstd22}

Masahiro Yamada
2022-01-09T18:16:16Z

GZIP-compressed files end with 4 byte data that represents the size
of the original input. The decompressors (the self-extracting kernel)
exploit it to know the vmlinux size beforehand. To mimic the GZIP's
trailer, Kbuild provides cmd_{bzip2,lzma,lzo,lz4,xzkern,zstd22}.
Unfortunately these macros are used everywhere despite the appended
size data is only useful for the decompressors.

There is no guarantee that such hand-crafted trailers are safely ignored.
In fact, the kernel refuses compressed initramdisks with the garbage
data. That is why usr/Makefile overrides size_append to make it no-op.

To limit the use of such broken compressed files, this commit renames
the existing macros as follows:

cmd_bzip2 --> cmd_bzip2_with_size
cmd_lzma --> cmd_lzma_with_size
cmd_lzo --> cmd_lzo_with_size
cmd_lz4 --> cmd_lz4_with_size
cmd_xzkern --> cmd_xzkern_with_size
cmd_zstd22 --> cmd_zstd22_with_size

To keep the decompressors working, I updated the following Makefiles
accordingly:

arch/arm/boot/compressed/Makefile
arch/h8300/boot/compressed/Makefile
arch/mips/boot/compressed/Makefile
arch/parisc/boot/compressed/Makefile
arch/s390/boot/compressed/Makefile
arch/sh/boot/compressed/Makefile
arch/x86/boot/compressed/Makefile

I reused the current macro names for the normal usecases; they produce
the compressed data in the proper format.

I did not touch the following:

arch/arc/boot/Makefile
arch/arm64/boot/Makefile
arch/csky/boot/Makefile
arch/mips/boot/Makefile
arch/riscv/boot/Makefile
arch/sh/boot/Makefile
kernel/Makefile

This means those Makefiles will stop appending the size data.

I dropped the 'override size_append' hack from usr/Makefile.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

arch/arm/boot/compressed/Makefile | 8 ++++----
arch/h8300/boot/compressed/Makefile | 4 +++-
arch/mips/boot/compressed/Makefile | 12 +++++------
arch/parisc/boot/compressed/Makefile | 10 +++++-----
arch/s390/boot/compressed/Makefile | 12 +++++------
arch/sh/boot/compressed/Makefile | 8 ++++----
arch/x86/boot/compressed/Makefile | 12 +++++------
scripts/Makefile.lib | 30 ++++++++++++++++++++++------
usr/Makefile | 5 -----
9 files changed, 58 insertions(+), 43 deletions(-)

diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index 91265e7ff672..adc0e318a1ea 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -77,10 +77,10 @@ CPPFLAGS_vmlinux.lds += -DTEXT_OFFSET="$(TEXT_OFFSET)"
CPPFLAGS_vmlinux.lds += -DMALLOC_SIZE="$(MALLOC_SIZE)"

compress-$(CONFIG_KERNEL_GZIP) = gzip
-compress-$(CONFIG_KERNEL_LZO) = lzo
-compress-$(CONFIG_KERNEL_LZMA) = lzma
-compress-$(CONFIG_KERNEL_XZ) = xzkern
-compress-$(CONFIG_KERNEL_LZ4) = lz4
+compress-$(CONFIG_KERNEL_LZO) = lzo_with_size
+compress-$(CONFIG_KERNEL_LZMA) = lzma_with_size
+compress-$(CONFIG_KERNEL_XZ) = xzkern_with_size
+compress-$(CONFIG_KERNEL_LZ4) = lz4_with_size

libfdt_objs := fdt_rw.o fdt_ro.o fdt_wip.o fdt.o

diff --git a/arch/h8300/boot/compressed/Makefile b/arch/h8300/boot/compressed/Makefile
index 5942793f77a0..6ab2fa5ba105 100644
--- a/arch/h8300/boot/compressed/Makefile
+++ b/arch/h8300/boot/compressed/Makefile
@@ -30,9 +30,11 @@ $(obj)/vmlinux.bin: vmlinux FORCE

suffix-$(CONFIG_KERNEL_GZIP) := gzip
suffix-$(CONFIG_KERNEL_LZO) := lzo
+compress-$(CONFIG_KERNEL_GZIP) := gzip
+compress-$(CONFIG_KERNEL_LZO) := lzo_with_size

$(obj)/vmlinux.bin.$(suffix-y): $(obj)/vmlinux.bin FORCE
- $(call if_changed,$(suffix-y))
+ $(call if_changed,$(compress-y))

LDFLAGS_piggy.o := -r --format binary --oformat elf32-h8300-linux -T
OBJCOPYFLAGS := -O binary
diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile
index f27cf31b4140..832f8001d7d9 100644
--- a/arch/mips/boot/compressed/Makefile
+++ b/arch/mips/boot/compressed/Makefile
@@ -64,12 +64,12 @@ $(obj)/vmlinux.bin: $(KBUILD_IMAGE) FORCE
$(call if_changed,objcopy)

tool_$(CONFIG_KERNEL_GZIP) = gzip
-tool_$(CONFIG_KERNEL_BZIP2) = bzip2
-tool_$(CONFIG_KERNEL_LZ4) = lz4
-tool_$(CONFIG_KERNEL_LZMA) = lzma
-tool_$(CONFIG_KERNEL_LZO) = lzo
-tool_$(CONFIG_KERNEL_XZ) = xzkern
-tool_$(CONFIG_KERNEL_ZSTD) = zstd22
+tool_$(CONFIG_KERNEL_BZIP2) = bzip2_with_size
+tool_$(CONFIG_KERNEL_LZ4) = lz4_with_size
+tool_$(CONFIG_KERNEL_LZMA) = lzma_with_size
+tool_$(CONFIG_KERNEL_LZO) = lzo_with_size
+tool_$(CONFIG_KERNEL_XZ) = xzkern_with_size
+tool_$(CONFIG_KERNEL_ZSTD) = zstd22_with_size

targets += vmlinux.bin.z

diff --git a/arch/parisc/boot/compressed/Makefile b/arch/parisc/boot/compressed/Makefile
index bf4f2891d0b7..2640f72d69ce 100644
--- a/arch/parisc/boot/compressed/Makefile
+++ b/arch/parisc/boot/compressed/Makefile
@@ -70,15 +70,15 @@ suffix-$(CONFIG_KERNEL_XZ) := xz
$(obj)/vmlinux.bin.gz: $(vmlinux.bin.all-y) FORCE
$(call if_changed,gzip)
$(obj)/vmlinux.bin.bz2: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,bzip2)
+ $(call if_changed,bzip2_with_size)
$(obj)/vmlinux.bin.lz4: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,lz4)
+ $(call if_changed,lz4_with_size)
$(obj)/vmlinux.bin.lzma: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,lzma)
+ $(call if_changed,lzma_with_size)
$(obj)/vmlinux.bin.lzo: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,lzo)
+ $(call if_changed,lzo_with_size)
$(obj)/vmlinux.bin.xz: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,xzkern)
+ $(call if_changed,xzkern_with_size)

LDFLAGS_piggy.o := -r --format binary --oformat $(LD_BFD) -T
$(obj)/piggy.o: $(obj)/vmlinux.scr $(obj)/vmlinux.bin.$(suffix-y) FORCE
diff --git a/arch/s390/boot/compressed/Makefile b/arch/s390/boot/compressed/Makefile
index 3b860061e84d..8ea880b7c3ec 100644
--- a/arch/s390/boot/compressed/Makefile
+++ b/arch/s390/boot/compressed/Makefile
@@ -71,17 +71,17 @@ suffix-$(CONFIG_KERNEL_ZSTD) := .zst
$(obj)/vmlinux.bin.gz: $(vmlinux.bin.all-y) FORCE
$(call if_changed,gzip)
$(obj)/vmlinux.bin.bz2: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,bzip2)
+ $(call if_changed,bzip2_with_size)
$(obj)/vmlinux.bin.lz4: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,lz4)
+ $(call if_changed,lz4_with_size)
$(obj)/vmlinux.bin.lzma: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,lzma)
+ $(call if_changed,lzma_with_size)
$(obj)/vmlinux.bin.lzo: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,lzo)
+ $(call if_changed,lzo_with_size)
$(obj)/vmlinux.bin.xz: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,xzkern)
+ $(call if_changed,xzkern_with_size)
$(obj)/vmlinux.bin.zst: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,zstd22)
+ $(call if_changed,zstd22_with_size)

OBJCOPYFLAGS_piggy.o := -I binary -O elf64-s390 -B s390:64-bit --rename-section .data=.vmlinux.bin.compressed
$(obj)/piggy.o: $(obj)/vmlinux.bin$(suffix-y) FORCE
diff --git a/arch/sh/boot/compressed/Makefile b/arch/sh/boot/compressed/Makefile
index c1eb9a62de55..a6808a403f4b 100644
--- a/arch/sh/boot/compressed/Makefile
+++ b/arch/sh/boot/compressed/Makefile
@@ -52,13 +52,13 @@ vmlinux.bin.all-y := $(obj)/vmlinux.bin
$(obj)/vmlinux.bin.gz: $(vmlinux.bin.all-y) FORCE
$(call if_changed,gzip)
$(obj)/vmlinux.bin.bz2: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,bzip2)
+ $(call if_changed,bzip2_with_size)
$(obj)/vmlinux.bin.lzma: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,lzma)
+ $(call if_changed,lzma_with_size)
$(obj)/vmlinux.bin.xz: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,xzkern)
+ $(call if_changed,xzkern_with_size)
$(obj)/vmlinux.bin.lzo: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,lzo)
+ $(call if_changed,lzo_with_size)

OBJCOPYFLAGS += -R .empty_zero_page

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 431bf7f846c3..2825c74bcae3 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -123,17 +123,17 @@ vmlinux.bin.all-$(CONFIG_X86_NEED_RELOCS) += $(obj)/vmlinux.relocs
$(obj)/vmlinux.bin.gz: $(vmlinux.bin.all-y) FORCE
$(call if_changed,gzip)
$(obj)/vmlinux.bin.bz2: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,bzip2)
+ $(call if_changed,bzip2_with_size)
$(obj)/vmlinux.bin.lzma: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,lzma)
+ $(call if_changed,lzma_with_size)
$(obj)/vmlinux.bin.xz: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,xzkern)
+ $(call if_changed,xzkern_with_size)
$(obj)/vmlinux.bin.lzo: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,lzo)
+ $(call if_changed,lzo_with_size)
$(obj)/vmlinux.bin.lz4: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,lz4)
+ $(call if_changed,lz4_with_size)
$(obj)/vmlinux.bin.zst: $(vmlinux.bin.all-y) FORCE
- $(call if_changed,zstd22)
+ $(call if_changed,zstd22_with_size)

suffix-$(CONFIG_KERNEL_GZIP) := gz
suffix-$(CONFIG_KERNEL_BZIP2) := bz2
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 5366466ea0e4..4207a72d429f 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -395,19 +395,31 @@ printf "%08x\n" $$dec_size | \
)

quiet_cmd_bzip2 = BZIP2 $@
- cmd_bzip2 = { cat $(real-prereqs) | $(KBZIP2) -9; $(size_append); } > $@
+ cmd_bzip2 = cat $(real-prereqs) | $(KBZIP2) -9 > $@
+
+quiet_cmd_bzip2_with_size = BZIP2 $@
+ cmd_bzip2_with_size = { cat $(real-prereqs) | $(KBZIP2) -9; $(size_append); } > $@

# Lzma
# ---------------------------------------------------------------------------

quiet_cmd_lzma = LZMA $@
- cmd_lzma = { cat $(real-prereqs) | $(LZMA) -9; $(size_append); } > $@
+ cmd_lzma = cat $(real-prereqs) | $(LZMA) -9 > $@
+
+quiet_cmd_lzma_with_size = LZMA $@
+ cmd_lzma_with_size = { cat $(real-prereqs) | $(LZMA) -9; $(size_append); } > $@

quiet_cmd_lzo = LZO $@
- cmd_lzo = { cat $(real-prereqs) | $(KLZOP) -9; $(size_append); } > $@
+ cmd_lzo = cat $(real-prereqs) | $(KLZOP) -9 > $@
+
+quiet_cmd_lzo_with_size = LZO $@
+ cmd_lzo_with_size = { cat $(real-prereqs) | $(KLZOP) -9; $(size_append); } > $@

quiet_cmd_lz4 = LZ4 $@
- cmd_lz4 = { cat $(real-prereqs) | $(LZ4) -l -c1 stdin stdout; \
+ cmd_lz4 = cat $(real-prereqs) | $(LZ4) -l -c1 stdin stdout > $@
+
+quiet_cmd_lz4_with_size = LZ4 $@
+ cmd_lz4_with_size = { cat $(real-prereqs) | $(LZ4) -l -c1 stdin stdout; \
$(size_append); } > $@

# U-Boot mkimage
@@ -450,7 +462,10 @@ quiet_cmd_uimage = UIMAGE $@
# big dictionary would increase the memory usage too much in the multi-call
# decompression mode. A BCJ filter isn't used either.
quiet_cmd_xzkern = XZKERN $@
- cmd_xzkern = { cat $(real-prereqs) | sh $(srctree)/scripts/xz_wrap.sh; \
+ cmd_xzkern = cat $(real-prereqs) | sh $(srctree)/scripts/xz_wrap.sh > $@
+
+quiet_cmd_xzkern_with_size = XZKERN $@
+ cmd_xzkern_with_size = { cat $(real-prereqs) | sh $(srctree)/scripts/xz_wrap.sh; \
$(size_append); } > $@

quiet_cmd_xzmisc = XZMISC $@
@@ -476,7 +491,10 @@ quiet_cmd_zstd = ZSTD $@
cmd_zstd = cat $(real-prereqs) | $(ZSTD) -19 > $@

quiet_cmd_zstd22 = ZSTD22 $@
- cmd_zstd22 = { cat $(real-prereqs) | $(ZSTD) -22 --ultra; $(size_append); } > $@
+ cmd_zstd22 = cat $(real-prereqs) | $(ZSTD) -22 --ultra > $@
+
+quiet_cmd_zstd22_with_size = ZSTD22 $@
+ cmd_zstd22_with_size = { cat $(real-prereqs) | $(ZSTD) -22 --ultra; $(size_append); } > $@

# ASM offsets
# ---------------------------------------------------------------------------
diff --git a/usr/Makefile b/usr/Makefile
index b1a81a40eab1..7b89c0175a3a 100644
--- a/usr/Makefile
+++ b/usr/Makefile
@@ -3,11 +3,6 @@
# kbuild file for usr/ - including initramfs image
#

-# 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 := :
-
compress-y := shipped
compress-$(CONFIG_INITRAMFS_COMPRESSION_GZIP) := gzip
compress-$(CONFIG_INITRAMFS_COMPRESSION_BZIP2) := bzip2
--
2.32.0