kbuild: rename cmd_{bzip2,lzma,lzo,lz4,xzkern,zstd22}

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 initramdfs 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 <[email protected]>
Reviewed-by: Nicolas Schier <[email protected]>

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
 

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

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
 

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

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

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
 

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

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
 # ---------------------------------------------------------------------------

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