From 0fe4f4ef8cc8e15a8f29f08f4be6128395f125f6 Mon Sep 17 00:00:00 2001 From: Nick Terrell Date: Thu, 30 Jul 2020 12:08:38 -0700 Subject: x86: Bump ZO_z_extra_bytes margin for zstd Bump the ZO_z_extra_bytes margin for zstd. Zstd needs 3 bytes per 128 KB, and has a 22 byte fixed overhead. Zstd needs to maintain 128 KB of space at all times, since that is the maximum block size. See the comments regarding in-place decompression added in lib/decompress_unzstd.c for details. The existing code is written so that all the compression algorithms use the same ZO_z_extra_bytes. It is taken to be the maximum of the growth rate plus the maximum fixed overhead. The comments just above this diff state that: Signed-off-by: Nick Terrell Signed-off-by: Ingo Molnar Tested-by: Sedat Dilek Reviewed-by: Kees Cook Link: https://lore.kernel.org/r/20200730190841.2071656-6-nickrterrell@gmail.com --- arch/x86/boot/header.S | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S index 735ad7f21ab0..6dbd7e9f74c9 100644 --- a/arch/x86/boot/header.S +++ b/arch/x86/boot/header.S @@ -539,8 +539,14 @@ 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) -- cgit v1.2.3 From fb46d057db824693994b048d3a8c869892afaa3f Mon Sep 17 00:00:00 2001 From: Nick Terrell Date: Thu, 30 Jul 2020 12:08:39 -0700 Subject: x86: Add support for ZSTD compressed kernel - Add support for zstd compressed kernel - Define __DISABLE_EXPORTS in Makefile - Remove __DISABLE_EXPORTS definition from kaslr.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 now defined in the Makefile, which covers both the existing use in kaslr.c, and the use needed by the zstd decompressor in misc.c. 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. Signed-off-by: Nick Terrell Signed-off-by: Ingo Molnar Tested-by: Sedat Dilek Reviewed-by: Kees Cook Link: https://lore.kernel.org/r/20200730190841.2071656-7-nickrterrell@gmail.com --- arch/x86/Kconfig | 1 + arch/x86/boot/compressed/Makefile | 6 +++++- arch/x86/boot/compressed/kaslr.c | 7 ------- arch/x86/boot/compressed/misc.c | 4 ++++ arch/x86/include/asm/boot.h | 11 +++++++++-- 5 files changed, 19 insertions(+), 10 deletions(-) (limited to 'arch') 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 5a828fde7a42..c08714ae76ec 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) @@ -42,6 +42,7 @@ KBUILD_CFLAGS += $(call cc-disable-warning, gnu) KBUILD_CFLAGS += -Wno-pointer-sign KBUILD_CFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=) KBUILD_CFLAGS += -fno-asynchronous-unwind-tables +KBUILD_CFLAGS += -D__DISABLE_EXPORTS KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__ GCOV_PROFILE := n @@ -145,6 +146,8 @@ $(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-$(CONFIG_KERNEL_BZIP2) := bz2 @@ -152,6 +155,7 @@ suffix-$(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/kaslr.c b/arch/x86/boot/compressed/kaslr.c index d7408af55738..0048269180d5 100644 --- a/arch/x86/boot/compressed/kaslr.c +++ b/arch/x86/boot/compressed/kaslr.c @@ -19,13 +19,6 @@ */ #define BOOT_CTYPE_H -/* - * _ctype[] in lib/ctype.c is needed by isspace() of linux/ctype.h. - * While both lib/ctype.c and lib/cmdline.c will bring EXPORT_SYMBOL - * which is meaningless and will cause compiling error in some cases. - */ -#define __DISABLE_EXPORTS - #include "misc.h" #include "error.h" #include "../string.h" diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index 9652d5c2afda..39e592d0e0b4 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -77,6 +77,10 @@ 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..9191280d9ea3 100644 --- a/arch/x86/include/asm/boot.h +++ b/arch/x86/include/asm/boot.h @@ -24,9 +24,16 @@ # 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) +/* + * Zstd needs to allocate the ZSTD_DCtx in order to decompress the kernel. + * The ZSTD_DCtx is ~160KB, so set the heap size to 192KB because it is a + * round number and to allow some slack. + */ +# define BOOT_HEAP_SIZE 0x30000 +#else # define BOOT_HEAP_SIZE 0x10000 #endif -- cgit v1.2.3