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Message-ID: <52673A1E.60005@roeck-us.net> Date: Tue, 22 Oct 2013 19:53:18 -0700 From: Guenter Roeck <linux@...ck-us.net> To: "H. Peter Anvin" <hpa@...or.com>, Andrew Boie <andrew.p.boie@...el.com>, linux-kernel@...r.kernel.org CC: tglx@...utronix.de, mmarek@...e.cz Subject: Re: [PATCH 1/1] x86: boot: support minigzip bzImage compression On 10/22/2013 05:26 PM, H. Peter Anvin wrote: > Wouldn't it be better to fix gzip than hacking around this in the kernel? > Or just change the build system to have /bin/gzip point to minigzip if so desired. I have done the same to replace it with pigz. Debian/Ubuntu provides the update-alternatives command for that purpose. If that is not available, just hard-link it. In general, I don't think it would be a good idea to add tool variant dependencies like this one to the kernel configuration. Guenter > Andrew Boie <andrew.p.boie@...el.com> wrote: >> 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 >> # >> --------------------------------------------------------------------------- >> > -- 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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