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bzip2/lzma: x86 kernel compression support
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Impact: Replaces x86 kernel decompressor with new code

This is the third part of the bzip2/lzma patch

The bzip patch is based on an idea by Christian Ludwig, includes support for
compressing the kernel with bzip2 or lzma rather than gzip. Both
compressors give smaller sizes than gzip.  Lzma's decompresses faster
than bzip2.

It also supports ramdisks and initramfs' compressed using these two
compressors.

The functionality has been successfully used for a couple of years by
the udpcast project

This version applies to "tip" kernel 2.6.28

This part contains:
- support for new bzip2 and lzma kernel compression for x86

Signed-off-by: Alain Knaff <alain@knaff.lu>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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Alain Knaff authored and H. Peter Anvin committed Jan 4, 2009
1 parent b172fd8 commit ae03c49
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Showing 3 changed files with 44 additions and 107 deletions.
21 changes: 19 additions & 2 deletions arch/x86/boot/compressed/Makefile
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@
# create a compressed vmlinux image from the original vmlinux
#

targets := vmlinux vmlinux.bin vmlinux.bin.gz head_$(BITS).o misc.o piggy.o
targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma head_$(BITS).o misc.o piggy.o

KBUILD_CFLAGS := -m$(BITS) -D__KERNEL__ $(LINUX_INCLUDE) -O2
KBUILD_CFLAGS += -fno-strict-aliasing -fPIC
Expand Down Expand Up @@ -47,18 +47,35 @@ ifeq ($(CONFIG_X86_32),y)
ifdef CONFIG_RELOCATABLE
$(obj)/vmlinux.bin.gz: $(obj)/vmlinux.bin.all FORCE
$(call if_changed,gzip)
$(obj)/vmlinux.bin.bz2: $(obj)/vmlinux.bin.all FORCE
$(call if_changed,bzip2)
$(obj)/vmlinux.bin.lzma: $(obj)/vmlinux.bin.all FORCE
$(call if_changed,lzma)
else
$(obj)/vmlinux.bin.gz: $(obj)/vmlinux.bin FORCE
$(call if_changed,gzip)
$(obj)/vmlinux.bin.bz2: $(obj)/vmlinux.bin FORCE
$(call if_changed,bzip2)
$(obj)/vmlinux.bin.lzma: $(obj)/vmlinux.bin FORCE
$(call if_changed,lzma)
endif
LDFLAGS_piggy.o := -r --format binary --oformat elf32-i386 -T

else

$(obj)/vmlinux.bin.gz: $(obj)/vmlinux.bin FORCE
$(call if_changed,gzip)
$(obj)/vmlinux.bin.bz2: $(obj)/vmlinux.bin FORCE
$(call if_changed,bzip2)
$(obj)/vmlinux.bin.lzma: $(obj)/vmlinux.bin FORCE
$(call if_changed,lzma)

LDFLAGS_piggy.o := -r --format binary --oformat elf64-x86-64 -T
endif

$(obj)/piggy.o: $(obj)/vmlinux.scr $(obj)/vmlinux.bin.gz FORCE
suffix_$(CONFIG_KERNEL_GZIP) = gz
suffix_$(CONFIG_KERNEL_BZIP2) = bz2
suffix_$(CONFIG_KERNEL_LZMA) = lzma

$(obj)/piggy.o: $(obj)/vmlinux.scr $(obj)/vmlinux.bin.$(suffix_y) FORCE
$(call if_changed,ld)
118 changes: 14 additions & 104 deletions arch/x86/boot/compressed/misc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -116,71 +116,13 @@
/*
* gzip declarations
*/

#define OF(args) args
#define STATIC static

#undef memset
#undef memcpy
#define memzero(s, n) memset((s), 0, (n))

typedef unsigned char uch;
typedef unsigned short ush;
typedef unsigned long ulg;

/*
* Window size must be at least 32k, and a power of two.
* We don't actually have a window just a huge output buffer,
* so we report a 2G window size, as that should always be
* larger than our output buffer:
*/
#define WSIZE 0x80000000

/* Input buffer: */
static unsigned char *inbuf;

/* Sliding window buffer (and final output buffer): */
static unsigned char *window;

/* Valid bytes in inbuf: */
static unsigned insize;

/* Index of next byte to be processed in inbuf: */
static unsigned inptr;

/* Bytes in output buffer: */
static unsigned outcnt;

/* gzip flag byte */
#define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */
#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gz file */
#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
#define ORIG_NAM 0x08 /* bit 3 set: original file name present */
#define COMMENT 0x10 /* bit 4 set: file comment present */
#define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */
#define RESERVED 0xC0 /* bit 6, 7: reserved */

#define get_byte() (inptr < insize ? inbuf[inptr++] : fill_inbuf())

/* Diagnostic functions */
#ifdef DEBUG
# define Assert(cond, msg) do { if (!(cond)) error(msg); } while (0)
# define Trace(x) do { fprintf x; } while (0)
# define Tracev(x) do { if (verbose) fprintf x ; } while (0)
# define Tracevv(x) do { if (verbose > 1) fprintf x ; } while (0)
# define Tracec(c, x) do { if (verbose && (c)) fprintf x ; } while (0)
# define Tracecv(c, x) do { if (verbose > 1 && (c)) fprintf x ; } while (0)
#else
# define Assert(cond, msg)
# define Trace(x)
# define Tracev(x)
# define Tracevv(x)
# define Tracec(c, x)
# define Tracecv(c, x)
#endif

static int fill_inbuf(void);
static void flush_window(void);
static void error(char *m);

/*
Expand All @@ -189,13 +131,8 @@ static void error(char *m);
static struct boot_params *real_mode; /* Pointer to real-mode data */
static int quiet;

extern unsigned char input_data[];
extern int input_len;

static long bytes_out;

static void *memset(void *s, int c, unsigned n);
static void *memcpy(void *dest, const void *src, unsigned n);
void *memcpy(void *dest, const void *src, unsigned n);

static void __putstr(int, const char *);
#define putstr(__x) __putstr(0, __x)
Expand All @@ -213,7 +150,17 @@ static char *vidmem;
static int vidport;
static int lines, cols;

#include "../../../../lib/inflate.c"
#ifdef CONFIG_KERNEL_GZIP
#include "../../../../lib/decompress_inflate.c"
#endif

#ifdef CONFIG_KERNEL_BZIP2
#include "../../../../lib/decompress_bunzip2.c"
#endif

#ifdef CONFIG_KERNEL_LZMA
#include "../../../../lib/decompress_unlzma.c"
#endif

static void scroll(void)
{
Expand Down Expand Up @@ -282,7 +229,7 @@ static void *memset(void *s, int c, unsigned n)
return s;
}

static void *memcpy(void *dest, const void *src, unsigned n)
void *memcpy(void *dest, const void *src, unsigned n)
{
int i;
const char *s = src;
Expand All @@ -293,38 +240,6 @@ static void *memcpy(void *dest, const void *src, unsigned n)
return dest;
}

/* ===========================================================================
* Fill the input buffer. This is called only when the buffer is empty
* and at least one byte is really needed.
*/
static int fill_inbuf(void)
{
error("ran out of input data");
return 0;
}

/* ===========================================================================
* Write the output window window[0..outcnt-1] and update crc and bytes_out.
* (Used for the decompressed data only.)
*/
static void flush_window(void)
{
/* With my window equal to my output buffer
* I only need to compute the crc here.
*/
unsigned long c = crc; /* temporary variable */
unsigned n;
unsigned char *in, ch;

in = window;
for (n = 0; n < outcnt; n++) {
ch = *in++;
c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);
}
crc = c;
bytes_out += (unsigned long)outcnt;
outcnt = 0;
}

static void error(char *x)
{
Expand Down Expand Up @@ -407,12 +322,8 @@ asmlinkage void decompress_kernel(void *rmode, memptr heap,
lines = real_mode->screen_info.orig_video_lines;
cols = real_mode->screen_info.orig_video_cols;

window = output; /* Output buffer (Normally at 1M) */
free_mem_ptr = heap; /* Heap */
free_mem_end_ptr = heap + BOOT_HEAP_SIZE;
inbuf = input_data; /* Input buffer */
insize = input_len;
inptr = 0;

#ifdef CONFIG_X86_64
if ((unsigned long)output & (__KERNEL_ALIGN - 1))
Expand All @@ -430,10 +341,9 @@ asmlinkage void decompress_kernel(void *rmode, memptr heap,
#endif
#endif

makecrc();
if (!quiet)
putstr("\nDecompressing Linux... ");
gunzip();
decompress(input_data, input_len, NULL, NULL, output, NULL, error);
parse_elf(output);
if (!quiet)
putstr("done.\nBooting the kernel.\n");
Expand Down
12 changes: 11 additions & 1 deletion arch/x86/include/asm/boot.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -15,11 +15,21 @@
+ (CONFIG_PHYSICAL_ALIGN - 1)) \
& ~(CONFIG_PHYSICAL_ALIGN - 1))

#if (defined CONFIG_KERNEL_BZIP2)
#define BOOT_HEAP_SIZE 0x400000
#else

#ifdef CONFIG_X86_64
#define BOOT_HEAP_SIZE 0x7000
#define BOOT_STACK_SIZE 0x4000
#else
#define BOOT_HEAP_SIZE 0x4000
#endif

#endif

#ifdef CONFIG_X86_64
#define BOOT_STACK_SIZE 0x4000
#else
#define BOOT_STACK_SIZE 0x1000
#endif

Expand Down

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