On Thu, Jul 23, 2020 at 9:30 PM Nick Terrell <nickrterrell@xxxxxxxxx> wrote: > > From: Nick Terrell <terrelln@xxxxxx> > > * Add support for zstd compressed kernel > * Define __DISABLE_EXPORTS in misc.c > * Bump the heap size for zstd. > * Update the documentation. > > Integrates the ZSTD decompression code to the x86 pre-boot code. > > Zstandard requires slightly more memory during the kernel decompression > on x86 (192 KB vs 64 KB), and the memory usage is independent of the > window size. > > __DISABLE_EXPORTS is defined in misc.c instead of the Makefile because > kaslr.c defines __DISABLE_EXPORTS, and defining it in the Makefile gives > duplicate definition warnings. > That was reported by Arvind - feel free to add a Reported-by: ... - Sedat - > This patch has been boot tested with both a zstd and gzip compressed > kernel on i386 and x86_64 using buildroot and QEMU. > > Additionally, this has been tested in production on x86_64 devices. > We saw a 2 second boot time reduction by switching kernel compression > from xz to zstd. > > Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> > Tested-by: Sedat Dilek <sedat.dilek@xxxxxxxxx> > Signed-off-by: Nick Terrell <terrelln@xxxxxx> > --- > Documentation/x86/boot.rst | 6 +++--- > arch/x86/Kconfig | 1 + > arch/x86/boot/compressed/Makefile | 5 ++++- > arch/x86/boot/compressed/misc.c | 9 +++++++++ > arch/x86/include/asm/boot.h | 6 ++++-- > 5 files changed, 21 insertions(+), 6 deletions(-) > > diff --git a/Documentation/x86/boot.rst b/Documentation/x86/boot.rst > index 5325c71ca877..7fafc7ac00d7 100644 > --- a/Documentation/x86/boot.rst > +++ b/Documentation/x86/boot.rst > @@ -782,9 +782,9 @@ Protocol: 2.08+ > uncompressed data should be determined using the standard magic > numbers. The currently supported compression formats are gzip > (magic numbers 1F 8B or 1F 9E), bzip2 (magic number 42 5A), LZMA > - (magic number 5D 00), XZ (magic number FD 37), and LZ4 (magic number > - 02 21). The uncompressed payload is currently always ELF (magic > - number 7F 45 4C 46). > + (magic number 5D 00), XZ (magic number FD 37), LZ4 (magic number > + 02 21) and ZSTD (magic number 28 B5). The uncompressed payload is > + currently always ELF (magic number 7F 45 4C 46). > > ============ ============== > Field name: payload_length > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index 883da0abf779..4a64395bc35d 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -188,6 +188,7 @@ config X86 > select HAVE_KERNEL_LZMA > select HAVE_KERNEL_LZO > select HAVE_KERNEL_XZ > + select HAVE_KERNEL_ZSTD > select HAVE_KPROBES > select HAVE_KPROBES_ON_FTRACE > select HAVE_FUNCTION_ERROR_INJECTION > diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile > index 7619742f91c9..3498cd990869 100644 > --- a/arch/x86/boot/compressed/Makefile > +++ b/arch/x86/boot/compressed/Makefile > @@ -26,7 +26,7 @@ OBJECT_FILES_NON_STANDARD := y > KCOV_INSTRUMENT := n > > targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \ > - vmlinux.bin.xz vmlinux.bin.lzo vmlinux.bin.lz4 > + vmlinux.bin.xz vmlinux.bin.lzo vmlinux.bin.lz4 vmlinux.bin.zst > > KBUILD_CFLAGS := -m$(BITS) -O2 > KBUILD_CFLAGS += -fno-strict-aliasing $(call cc-option, -fPIE, -fPIC) > @@ -145,6 +145,8 @@ $(obj)/vmlinux.bin.lzo: $(vmlinux.bin.all-y) FORCE > $(call if_changed,lzo) > $(obj)/vmlinux.bin.lz4: $(vmlinux.bin.all-y) FORCE > $(call if_changed,lz4) > +$(obj)/vmlinux.bin.zst: $(vmlinux.bin.all-y) FORCE > + $(call if_changed,zstd22) > > suffix-$(CONFIG_KERNEL_GZIP) := gz > suffix-$(CONFIG_KERNEL_BZIP2) := bz2 > @@ -152,6 +154,7 @@ suffix-$(CONFIG_KERNEL_LZMA) := lzma > suffix-$(CONFIG_KERNEL_XZ) := xz > suffix-$(CONFIG_KERNEL_LZO) := lzo > suffix-$(CONFIG_KERNEL_LZ4) := lz4 > +suffix-$(CONFIG_KERNEL_ZSTD) := zst > > quiet_cmd_mkpiggy = MKPIGGY $@ > cmd_mkpiggy = $(obj)/mkpiggy $< > $@ > diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c > index 9652d5c2afda..885dc20680c2 100644 > --- a/arch/x86/boot/compressed/misc.c > +++ b/arch/x86/boot/compressed/misc.c > @@ -12,6 +12,11 @@ > * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996 > */ > > +/* decompressors bring in EXPORT_SYMBOL which is meaningless and will > + * cause compiler errors in some cases. > + */ > +#define __DISABLE_EXPORTS > + > #include "misc.h" > #include "error.h" > #include "pgtable.h" > @@ -77,6 +82,10 @@ static int lines, cols; > #ifdef CONFIG_KERNEL_LZ4 > #include "../../../../lib/decompress_unlz4.c" > #endif > + > +#ifdef CONFIG_KERNEL_ZSTD > +#include "../../../../lib/decompress_unzstd.c" > +#endif > /* > * NOTE: When adding a new decompressor, please update the analysis in > * ../header.S. > diff --git a/arch/x86/include/asm/boot.h b/arch/x86/include/asm/boot.h > index 680c320363db..d6dd43d25d9f 100644 > --- a/arch/x86/include/asm/boot.h > +++ b/arch/x86/include/asm/boot.h > @@ -24,9 +24,11 @@ > # error "Invalid value for CONFIG_PHYSICAL_ALIGN" > #endif > > -#ifdef CONFIG_KERNEL_BZIP2 > +#if defined(CONFIG_KERNEL_BZIP2) > # define BOOT_HEAP_SIZE 0x400000 > -#else /* !CONFIG_KERNEL_BZIP2 */ > +#elif defined(CONFIG_KERNEL_ZSTD) > +# define BOOT_HEAP_SIZE 0x30000 > +#else > # define BOOT_HEAP_SIZE 0x10000 > #endif > > -- > 2.27.0 >
