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x86: support XZ-compressed kernel

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This integrates the XZ decompression code to the x86 pre-boot code.

mkpiggy.c is updated to reserve about 32 KiB more buffer safety margin for
kernel decompression.  It is done unconditionally for all decompressors to
keep the code simpler.

The XZ decompressor needs around 30 KiB of heap, so the heap size is
increased to 32 KiB on both x86-32 and x86-64.

Documentation/x86/boot.txt is updated to list the XZ magic number.

With the x86 BCJ filter in XZ, XZ-compressed x86 kernel tends to be a few
percent smaller than the equivalent LZMA-compressed kernel.

Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alain Knaff <alain@knaff.lu>
Cc: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Cc: Phillip Lougher <phillip@lougher.demon.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Lasse Collin 2011-01-12 17:01:24 -08:00 committed by Linus Torvalds
parent 3ebe12439b
commit 303148045a
6 changed files with 14 additions and 10 deletions
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6
Documentation/x86/boot.txt
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@ -622,9 +622,9 @@ Protocol: 2.08+
The payload may be compressed. The format of both the compressed and The payload may be compressed. The format of both the compressed and
uncompressed data should be determined using the standard magic uncompressed data should be determined using the standard magic
numbers. The currently supported compression formats are gzip numbers. The currently supported compression formats are gzip
(magic numbers 1F 8B or 1F 9E), bzip2 (magic number 42 5A) and LZMA (magic numbers 1F 8B or 1F 9E), bzip2 (magic number 42 5A), LZMA
(magic number 5D 00). The uncompressed payload is currently always ELF (magic number 5D 00), and XZ (magic number FD 37). The uncompressed
(magic number 7F 45 4C 46). payload is currently always ELF (magic number 7F 45 4C 46).
Field name: payload_length Field name: payload_length
Type: read Type: read

1
arch/x86/Kconfig
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@ -51,6 +51,7 @@ config X86
select HAVE_KERNEL_GZIP select HAVE_KERNEL_GZIP
select HAVE_KERNEL_BZIP2 select HAVE_KERNEL_BZIP2
select HAVE_KERNEL_LZMA select HAVE_KERNEL_LZMA
select HAVE_KERNEL_XZ
select HAVE_KERNEL_LZO select HAVE_KERNEL_LZO
select HAVE_HW_BREAKPOINT select HAVE_HW_BREAKPOINT
select HAVE_MIXED_BREAKPOINTS_REGS select HAVE_MIXED_BREAKPOINTS_REGS

5
arch/x86/boot/compressed/Makefile
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@ -4,7 +4,7 @@
# create a compressed vmlinux image from the original vmlinux # create a compressed vmlinux image from the original vmlinux
# #
targets := vmlinux.lds vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma vmlinux.bin.lzo head_$(BITS).o misc.o string.o cmdline.o early_serial_console.o piggy.o targets := vmlinux.lds vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma vmlinux.bin.xz vmlinux.bin.lzo head_$(BITS).o misc.o string.o cmdline.o early_serial_console.o piggy.o
KBUILD_CFLAGS := -m$(BITS) -D__KERNEL__ $(LINUX_INCLUDE) -O2 KBUILD_CFLAGS := -m$(BITS) -D__KERNEL__ $(LINUX_INCLUDE) -O2
KBUILD_CFLAGS += -fno-strict-aliasing -fPIC KBUILD_CFLAGS += -fno-strict-aliasing -fPIC
@ -49,12 +49,15 @@ $(obj)/vmlinux.bin.bz2: $(vmlinux.bin.all-y) FORCE
$(call if_changed,bzip2) $(call if_changed,bzip2)
$(obj)/vmlinux.bin.lzma: $(vmlinux.bin.all-y) FORCE $(obj)/vmlinux.bin.lzma: $(vmlinux.bin.all-y) FORCE
$(call if_changed,lzma) $(call if_changed,lzma)
$(obj)/vmlinux.bin.xz: $(vmlinux.bin.all-y) FORCE
$(call if_changed,xzkern)
$(obj)/vmlinux.bin.lzo: $(vmlinux.bin.all-y) FORCE $(obj)/vmlinux.bin.lzo: $(vmlinux.bin.all-y) FORCE
$(call if_changed,lzo) $(call if_changed,lzo)
suffix-$(CONFIG_KERNEL_GZIP) := gz suffix-$(CONFIG_KERNEL_GZIP) := gz
suffix-$(CONFIG_KERNEL_BZIP2) := bz2 suffix-$(CONFIG_KERNEL_BZIP2) := bz2
suffix-$(CONFIG_KERNEL_LZMA) := lzma suffix-$(CONFIG_KERNEL_LZMA) := lzma
suffix-$(CONFIG_KERNEL_XZ) := xz
suffix-$(CONFIG_KERNEL_LZO) := lzo suffix-$(CONFIG_KERNEL_LZO) := lzo
quiet_cmd_mkpiggy = MKPIGGY $@ quiet_cmd_mkpiggy = MKPIGGY $@

4
arch/x86/boot/compressed/misc.c
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@ -139,6 +139,10 @@ static int lines, cols;
#include "../../../../lib/decompress_unlzma.c" #include "../../../../lib/decompress_unlzma.c"
#endif #endif
#ifdef CONFIG_KERNEL_XZ
#include "../../../../lib/decompress_unxz.c"
#endif
#ifdef CONFIG_KERNEL_LZO #ifdef CONFIG_KERNEL_LZO
#include "../../../../lib/decompress_unlzo.c" #include "../../../../lib/decompress_unlzo.c"
#endif #endif

2
arch/x86/boot/compressed/mkpiggy.c
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@ -74,7 +74,7 @@ int main(int argc, char *argv[])
offs = (olen > ilen) ? olen - ilen : 0; offs = (olen > ilen) ? olen - ilen : 0;
offs += olen >> 12; /* Add 8 bytes for each 32K block */ offs += olen >> 12; /* Add 8 bytes for each 32K block */
offs += 32*1024 + 18; /* Add 32K + 18 bytes slack */ offs += 64*1024 + 128; /* Add 64K + 128 bytes slack */
offs = (offs+4095) & ~4095; /* Round to a 4K boundary */ offs = (offs+4095) & ~4095; /* Round to a 4K boundary */
printf(".section \".rodata..compressed\",\"a\",@progbits\n"); printf(".section \".rodata..compressed\",\"a\",@progbits\n");

6
arch/x86/include/asm/boot.h
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@ -32,11 +32,7 @@
#define BOOT_HEAP_SIZE 0x400000 #define BOOT_HEAP_SIZE 0x400000
#else /* !CONFIG_KERNEL_BZIP2 */ #else /* !CONFIG_KERNEL_BZIP2 */
#ifdef CONFIG_X86_64 #define BOOT_HEAP_SIZE 0x8000
#define BOOT_HEAP_SIZE 0x7000
#else
#define BOOT_HEAP_SIZE 0x4000
#endif
#endif /* !CONFIG_KERNEL_BZIP2 */ #endif /* !CONFIG_KERNEL_BZIP2 */