Messages in this thread Patch in this message | | | From | Nick Terrell <> | Subject | [PATCH v2 2/2] x86: Add support for ZSTD-compressed kernel | Date | Thu, 12 Oct 2017 15:11:38 -0700 |
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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.
Zstandard requires memory proportional to the window size used during compression for decompressing the ramdisk image, since streaming mode is used. Newer versions of zstd (1.3.2+) list the window size of a file with `zstd -lv <file>'. The absolute maximum amount of memory required is just over 8 MB.
Signed-off-by: Nick Terrell <terrelln@fb.com> --- Documentation/x86/boot.txt | 6 +++--- arch/x86/Kconfig | 1 + arch/x86/boot/compressed/Makefile | 5 ++++- arch/x86/boot/compressed/misc.c | 4 ++++ arch/x86/boot/header.S | 8 +++++++- arch/x86/include/asm/boot.h | 6 ++++-- 6 files changed, 23 insertions(+), 7 deletions(-)
diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.txt index 5e9b826..7f5d1f9 100644 --- a/Documentation/x86/boot.txt +++ b/Documentation/x86/boot.txt @@ -666,9 +666,9 @@ 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 Type: read diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 971feac..e34e3e5 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -150,6 +150,7 @@ 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_KRETPROBES diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 8a95827..118a423 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -23,7 +23,7 @@ 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) -D__KERNEL__ -O2 KBUILD_CFLAGS += -fno-strict-aliasing $(call cc-option, -fPIE, -fPIC) @@ -133,6 +133,8 @@ $(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 + $(call if_changed,zstd) suffix-$(CONFIG_KERNEL_GZIP) := gz suffix-$(CONFIG_KERNEL_BZIP2) := bz2 @@ -140,6 +142,7 @@ suffix-$(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 $< > $@ || ( rm -f $@ ; false ) diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index c14217c..8140895 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -74,6 +74,10 @@ 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/boot/header.S b/arch/x86/boot/header.S index 1bb08ec..11b70e1 100644 --- a/arch/x86/boot/header.S +++ b/arch/x86/boot/header.S @@ -526,8 +526,14 @@ pref_address: .quad LOAD_PHYSICAL_ADDR # preferred load addr # the size-dependent part now grows so fast. # # extra_bytes = (uncompressed_size >> 8) + 65536 +# +# ZSTD compressed data grows by at most 3 bytes per 128K, and only has a 22 +# byte fixed overhead but has a maximum block size of 128K, so it needs a +# larger margin. +# +# extra_bytes = (uncompressed_size >> 8) + 131072 -#define ZO_z_extra_bytes ((ZO_z_output_len >> 8) + 65536) +#define ZO_z_extra_bytes ((ZO_z_output_len >> 8) + 131072) #if ZO_z_output_len > ZO_z_input_len # define ZO_z_extract_offset (ZO_z_output_len + ZO_z_extra_bytes - \ ZO_z_input_len) diff --git a/arch/x86/include/asm/boot.h b/arch/x86/include/asm/boot.h index abd06b1..dcfdd4e 100644 --- a/arch/x86/include/asm/boot.h +++ b/arch/x86/include/asm/boot.h @@ -23,9 +23,11 @@ # 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 -- 2.9.5
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