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Date: Tue, 22 Oct 2013 14:07:21 -0700 From: Andrew Boie <andrew.p.boie@...el.com> To: linux-kernel@...r.kernel.org Cc: hpa@...or.com, tglx@...utronix.de, mmarek@...e.cz, Andrew Boie <andrew.p.boie@...el.com> Subject: [PATCH 1/1] x86: boot: support minigzip bzImage compression Android OTA system computes very efficient diffs of compressed files if the deflate() algorithm it has access to is the same version as used to create the original file. Here we add support for compressing the kernel with 'minigzip' which uses the deflate() inside zlib. This is much better than using 'gzip' as that tool has a very old version of deflate() inside the gzip codebase instead of linking against zlib. Signed-off-by: Andrew Boie <andrew.p.boie@...el.com> --- arch/x86/Kconfig | 1 + arch/x86/boot/compressed/Makefile | 3 +++ arch/x86/boot/compressed/misc.c | 2 +- init/Kconfig | 18 +++++++++++++++++- scripts/Makefile.lib | 7 +++++++ 5 files changed, 29 insertions(+), 2 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index f67e839..aa91cef 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -62,6 +62,7 @@ config X86 select HAVE_REGS_AND_STACK_ACCESS_API select HAVE_DMA_API_DEBUG select HAVE_KERNEL_GZIP + select HAVE_KERNEL_MINIGZIP select HAVE_KERNEL_BZIP2 select HAVE_KERNEL_LZMA select HAVE_KERNEL_XZ diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index dcd90df..f000791 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -56,6 +56,8 @@ 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.mgz: $(vmlinux.bin.all-y) FORCE + $(call if_changed,minigzip) $(obj)/vmlinux.bin.bz2: $(vmlinux.bin.all-y) FORCE $(call if_changed,bzip2) $(obj)/vmlinux.bin.lzma: $(vmlinux.bin.all-y) FORCE @@ -68,6 +70,7 @@ $(obj)/vmlinux.bin.lz4: $(vmlinux.bin.all-y) FORCE $(call if_changed,lz4) suffix-$(CONFIG_KERNEL_GZIP) := gz +suffix-$(CONFIG_KERNEL_MINIGZIP):= mgz suffix-$(CONFIG_KERNEL_BZIP2) := bz2 suffix-$(CONFIG_KERNEL_LZMA) := lzma suffix-$(CONFIG_KERNEL_XZ) := xz diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index 434f077..4e55d32 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -125,7 +125,7 @@ static char *vidmem; static int vidport; static int lines, cols; -#ifdef CONFIG_KERNEL_GZIP +#if defined(CONFIG_KERNEL_GZIP) || defined(CONFIG_KERNEL_MINIGZIP) #include "../../../../lib/decompress_inflate.c" #endif diff --git a/init/Kconfig b/init/Kconfig index 3ecd8a1..818f225 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -100,6 +100,9 @@ config LOCALVERSION_AUTO config HAVE_KERNEL_GZIP bool +config HAVE_KERNEL_MINIGZIP + bool + config HAVE_KERNEL_BZIP2 bool @@ -118,7 +121,7 @@ config HAVE_KERNEL_LZ4 choice prompt "Kernel compression mode" default KERNEL_GZIP - depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4 + depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_MINIGZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4 help The linux kernel is a kind of self-extracting executable. Several compression algorithms are available, which differ @@ -144,6 +147,19 @@ config KERNEL_GZIP The old and tried gzip compression. It provides a good balance between compression ratio and decompression speed. +config KERNEL_MINIGZIP + bool "Minigzip" + depends on HAVE_KERNEL_MINIGZIP + help + Use minigzip to compress the bzImage. This is very similar to gzip + but uses the zlib library to compress, rather than the very old version + of zlib inside the gzip codebase. This is used for Android kernels + so that the same version of the deflate() algorithm is used when + building the kernel and constructing diffs with OTA applypatch, which + uncompresses sections of files that it detects are gzipped before computing + the diffs. If the versions of deflate() are out of alignment the binary + diffs tend to be very large. + config KERNEL_BZIP2 bool "Bzip2" depends on HAVE_KERNEL_BZIP2 diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 49392ec..deb1bb8 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -240,6 +240,13 @@ quiet_cmd_gzip = GZIP $@ cmd_gzip = (cat $(filter-out FORCE,$^) | gzip -n -f -9 > $@) || \ (rm -f $@ ; false) +# Minigzip +# --------------------------------------------------------------------------- + +quiet_cmd_minigzip = MINGZIP $@ +cmd_minigzip = (cat $(filter-out FORCE,$^) | minigzip -c -9 > $@) || \ + (rm -f $@ ; false) + # DTC # --------------------------------------------------------------------------- -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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