x86: support XZ-compressed kernel

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>

diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.txt
index bdeb81ccb5f61b973280f9704f28a9f9cd8cc2e1..9b7221a86df291e6c651e66a3bebc41c69256633 100644 (file)
--- a/Documentation/x86/boot.txt
+++ b/Documentation/x86/boot.txt
@@ -622,9 +622,9 @@ Protocol:   2.08+
   The payload may be compressed. The format of both the compressed and
   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) and LZMA
-  (magic number 5D 00).  The uncompressed payload is currently always ELF
-  (magic number 7F 45 4C 46).
+  (magic numbers 1F 8B or 1F 9E), bzip2 (magic number 42 5A), LZMA
+  (magic number 5D 00), and XZ (magic number FD 37).  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 8734db3c5830a99dc2145f612cfe213054f9f533..6e15fa9455e0cc964e9612f6f336f6a5b06f380c 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -51,6 +51,7 @@ config X86
        select HAVE_KERNEL_GZIP
        select HAVE_KERNEL_BZIP2
        select HAVE_KERNEL_LZMA
+       select HAVE_KERNEL_XZ
        select HAVE_KERNEL_LZO
        select HAVE_HW_BREAKPOINT
        select HAVE_MIXED_BREAKPOINTS_REGS

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 0c229551eead15adb41e5636aa7fce7233ebc555..09664efb9ceee4b128457f56d5fb72cb575d0ce4 100644 (file)
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -4,7 +4,7 @@
 # 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 += -fno-strict-aliasing -fPIC
@@ -49,12 +49,15 @@ $(obj)/vmlinux.bin.bz2: $(vmlinux.bin.all-y) FORCE
        $(call if_changed,bzip2)
 $(obj)/vmlinux.bin.lzma: $(vmlinux.bin.all-y) FORCE
        $(call if_changed,lzma)
+$(obj)/vmlinux.bin.xz: $(vmlinux.bin.all-y) FORCE
+       $(call if_changed,xzkern)
 $(obj)/vmlinux.bin.lzo: $(vmlinux.bin.all-y) FORCE
        $(call if_changed,lzo)
 
 suffix-$(CONFIG_KERNEL_GZIP)   := gz
 suffix-$(CONFIG_KERNEL_BZIP2)  := bz2
 suffix-$(CONFIG_KERNEL_LZMA)   := lzma
+suffix-$(CONFIG_KERNEL_XZ)     := xz
 suffix-$(CONFIG_KERNEL_LZO)    := lzo
 
 quiet_cmd_mkpiggy = MKPIGGY $@

diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 325c05294fc40dfc662a52187eba92516e568e94..3a19d04cebebe920e78269693c97637a19404b3b 100644 (file)
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -139,6 +139,10 @@ static int lines, cols;
 #include "../../../../lib/decompress_unlzma.c"
 #endif
 
+#ifdef CONFIG_KERNEL_XZ
+#include "../../../../lib/decompress_unxz.c"
+#endif
+
 #ifdef CONFIG_KERNEL_LZO
 #include "../../../../lib/decompress_unlzo.c"
 #endif

diff --git a/arch/x86/boot/compressed/mkpiggy.c b/arch/x86/boot/compressed/mkpiggy.c
index 5c228129d175779976b1985f8af86c5b9d80a668..646aa78ba5fdb2fe89e54d52b88a2ce5f7c6e20f 100644 (file)
--- a/arch/x86/boot/compressed/mkpiggy.c
+++ b/arch/x86/boot/compressed/mkpiggy.c
@@ -74,7 +74,7 @@ int main(int argc, char *argv[])
 
        offs = (olen > ilen) ? olen - ilen : 0;
        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 */
 
        printf(".section \".rodata..compressed\",\"a\",@progbits\n");

diff --git a/arch/x86/include/asm/boot.h b/arch/x86/include/asm/boot.h
index 3b62ab56c7a04a92ad795dbe627401981bf1485a..5e1a2eef3e7cadc5333368ffa5be053692e33e3a 100644 (file)
--- a/arch/x86/include/asm/boot.h
+++ b/arch/x86/include/asm/boot.h
@@ -32,11 +32,7 @@
 #define BOOT_HEAP_SIZE             0x400000
 #else /* !CONFIG_KERNEL_BZIP2 */
 
-#ifdef CONFIG_X86_64
-#define BOOT_HEAP_SIZE 0x7000
-#else
-#define BOOT_HEAP_SIZE 0x4000
-#endif
+#define BOOT_HEAP_SIZE 0x8000
 
 #endif /* !CONFIG_KERNEL_BZIP2 */