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[Xen-devel] [PATCH 04/10] i386: clean up bzImage generation



This patch cleans up image generation in several ways:
 - Firstly, it removes tools/build, and uses binutils to do all the
   final construction of the bzImage.  This removes a chunk of code
   and makes the image generation more flexible, since we can compute
   various numbers rather than be forced to use fixed constants.

 - Rename compressed/vmlinux to compressed/blob, to make it a
   bit clearer that it's the compressed kernel image + decompressor
   (now all the files named "vmlinux*" are directly derived from
   the kernel vmlinux).

 - Rather than using objcopy to wrap the compressed kernel into an
   object file, simply use the assembler: payload.S does a .bininc
   of the blob.bin file, which allows us to easily place
   it into a section, and it makes the Makefile dependency a little
   clearer.

 - Similarly, use the same technique to create compressed/piggy.o,
   which cleans things up even more, since the .S file can also
   set the input and output_size symbols without further linker
   script hackery; it also removes a complete linker script.

 - Also, remove stray "sti"

Signed-off-by: Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>

---
 arch/i386/boot/Makefile               |   31 +-----
 arch/i386/boot/compressed/Makefile    |   13 --
 arch/i386/boot/compressed/piggy.S     |   10 +
 arch/i386/boot/compressed/vmlinux.scr |   10 -
 arch/i386/boot/header.S               |    7 -
 arch/i386/boot/payload.S              |    3 
 arch/i386/boot/setup.ld               |   37 ++++---
 arch/i386/boot/tools/.gitignore       |    1 
 arch/i386/boot/tools/build.c          |  168 ---------------------------------
 9 files changed, 55 insertions(+), 225 deletions(-)

===================================================================
--- a/arch/i386/boot/Makefile
+++ b/arch/i386/boot/Makefile
@@ -25,12 +25,13 @@ SVGA_MODE := -DSVGA_MODE=NORMAL_VGA
 
 #RAMDISK := -DRAMDISK=512
 
-targets                := vmlinux.bin setup.bin setup.elf zImage bzImage
+targets                := blob.bin setup.elf zImage bzImage
 subdir-        := compressed
 
 setup-y                += a20.o apm.o cmdline.o copy.o cpu.o cpucheck.o edd.o
-setup-y                += header.o main.o mca.o memory.o pm.o pmjump.o
-setup-y                += printf.o string.o tty.o video.o version.o voyager.o
+setup-y                += header.o main.o mca.o memory.o payload.o pm.o
+setup-y                += pmjump.o printf.o string.o tty.o video.o version.o
+setup-y                += voyager.o
 
 # The link order of the video-*.o modules can matter.  In particular,
 # video-vga.o *must* be listed first, followed by video-vesa.o.
@@ -39,10 +40,6 @@ setup-y              += video-vga.o
 setup-y                += video-vga.o
 setup-y                += video-vesa.o
 setup-y                += video-bios.o
-
-hostprogs-y    := tools/build
-
-HOSTCFLAGS_build.o := $(LINUXINCLUDE)
 
 # ---------------------------------------------------------------------------
 
@@ -65,18 +62,12 @@ AFLAGS              := $(CFLAGS) -D__ASSEMBLY__
 $(obj)/bzImage: IMAGE_OFFSET := 0x100000
 $(obj)/bzImage: EXTRA_CFLAGS := -D__BIG_KERNEL__
 $(obj)/bzImage: EXTRA_AFLAGS := $(SVGA_MODE) $(RAMDISK) -D__BIG_KERNEL__
-$(obj)/bzImage: BUILDFLAGS   := -b
 
-quiet_cmd_image = BUILD   $@
-cmd_image = $(obj)/tools/build $(BUILDFLAGS) $(obj)/setup.bin \
-           $(obj)/vmlinux.bin $(ROOT_DEV) > $@
-
-$(obj)/zImage $(obj)/bzImage: $(obj)/setup.bin \
-                             $(obj)/vmlinux.bin $(obj)/tools/build FORCE
-       $(call if_changed,image)
+$(obj)/zImage $(obj)/bzImage: $(obj)/setup.elf FORCE
+       $(call if_changed,objcopy)
        @echo 'Kernel: $@ is ready' ' (#'`cat .version`')'
 
-$(obj)/vmlinux.bin: $(obj)/compressed/vmlinux FORCE
+$(obj)/blob.bin: $(obj)/compressed/blob FORCE
        $(call if_changed,objcopy)
 
 SETUP_OBJS = $(addprefix $(obj)/,$(setup-y))
@@ -85,12 +76,10 @@ LDFLAGS_setup.elf   := -T
 $(obj)/setup.elf: $(src)/setup.ld $(SETUP_OBJS) FORCE
        $(call if_changed,ld)
 
-OBJCOPYFLAGS_setup.bin := -O binary
+$(obj)/payload.o:      EXTRA_AFLAGS := -Wa,-I$(obj)
+$(obj)/payload.o: $(src)/payload.S $(obj)/blob.bin
 
-$(obj)/setup.bin: $(obj)/setup.elf FORCE
-       $(call if_changed,objcopy)
-
-$(obj)/compressed/vmlinux: FORCE
+$(obj)/compressed/blob: FORCE
        $(Q)$(MAKE) $(build)=$(obj)/compressed IMAGE_OFFSET=$(IMAGE_OFFSET) $@
 
 # Set this if you want to pass append arguments to the zdisk/fdimage/isoimage 
kernel
===================================================================
--- a/arch/i386/boot/compressed/Makefile
+++ b/arch/i386/boot/compressed/Makefile
@@ -4,11 +4,10 @@
 # create a compressed vmlinux image from the original vmlinux
 #
 
-targets                := vmlinux vmlinux.bin vmlinux.bin.gz head.o misc.o 
piggy.o \
+targets                := blob vmlinux.bin vmlinux.bin.gz head.o misc.o 
piggy.o \
                        vmlinux.bin.all vmlinux.relocs
-EXTRA_AFLAGS   := -traditional
 
-LDFLAGS_vmlinux := -T
+LDFLAGS_blob   := -T
 hostprogs-y    := relocs
 
 CFLAGS  := -m32 -D__KERNEL__ $(LINUX_INCLUDE) -O2 \
@@ -17,7 +16,7 @@ CFLAGS  := -m32 -D__KERNEL__ $(LINUX_INC
           $(call cc-option,-fno-stack-protector)
 LDFLAGS := -m elf_i386
 
-$(obj)/vmlinux: $(src)/vmlinux.lds $(obj)/head.o $(obj)/misc.o $(obj)/piggy.o 
FORCE
+$(obj)/blob: $(src)/vmlinux.lds $(obj)/head.o $(obj)/misc.o $(obj)/piggy.o 
FORCE
        $(call if_changed,ld)
        @:
 
@@ -44,7 +43,5 @@ else
        $(call if_changed,gzip)
 endif
 
-LDFLAGS_piggy.o := -r --format binary --oformat elf32-i386 -T
-
-$(obj)/piggy.o: $(src)/vmlinux.scr $(obj)/vmlinux.bin.gz FORCE
-       $(call if_changed,ld)
+$(obj)/piggy.o:        EXTRA_AFLAGS := -Wa,-I$(obj)
+$(obj)/piggy.o: $(src)/piggy.S $(obj)/vmlinux.bin.gz
===================================================================
--- /dev/null
+++ b/arch/i386/boot/compressed/piggy.S
@@ -0,0 +1,10 @@
+.section .data.compressed,"a",@progbits
+
+.globl input_data, input_len, output_len
+
+input_len:     .long input_data_end - input_data
+
+input_data:
+.incbin "vmlinux.bin.gz"
+output_len = .-4
+input_data_end:
===================================================================
--- a/arch/i386/boot/compressed/vmlinux.scr
+++ /dev/null
@@ -1,10 +0,0 @@
-SECTIONS
-{
-  .data.compressed : {
-       input_len = .;
-       LONG(input_data_end - input_data) input_data = .; 
-       *(.data) 
-       output_len = . - 4;
-       input_data_end = .; 
-       }
-}
===================================================================
--- a/arch/i386/boot/header.S
+++ b/arch/i386/boot/header.S
@@ -97,9 +97,9 @@ bugger_off_msg:
        .section ".header", "a"
        .globl  hdr
 hdr:
-setup_sects:   .byte SETUPSECTS
+setup_sects:   .byte _setup_sects
 root_flags:    .word ROOT_RDONLY
-syssize:       .long SYSSIZE
+syssize:       .long kernel_size_para
 ram_size:      .word RAMDISK
 vid_mode:      .word SVGA_MODE
 root_dev:      .word ROOT_DEV
@@ -148,7 +148,7 @@ CAN_USE_HEAP        = 0x80                  # If set, the 
load
                .byte   LOADED_HIGH
 #endif
 
-setup_move_size: .word  0x8000         # size to move, when setup is not
+setup_move_size: .word  _setup_size    # size to move, when setup is not
                                        # loaded at 0x90000. We will move setup
                                        # to 0x90000 then just before jumping
                                        # into the kernel. However, only the
@@ -246,7 +246,6 @@ setup2:
        jnz     1f
        movw    $0xfffc, %sp    # Make sure we're not zero
 1:     movzwl  %sp, %esp       # Clear upper half of %esp
-       sti
 
 # Check signature at end of setup
        cmpl    $0x5a5aaa55, setup_sig
===================================================================
--- /dev/null
+++ b/arch/i386/boot/payload.S
@@ -0,0 +1,3 @@
+.section .kernel,"a",@progbits
+
+.incbin "blob.bin"
===================================================================
--- a/arch/i386/boot/setup.ld
+++ b/arch/i386/boot/setup.ld
@@ -3,18 +3,16 @@
  *
  * Linker script for the i386 setup code
  */
-OUTPUT_FORMAT("elf32-i386", "elf32-i386", "elf32-i386")
+OUTPUT_FORMAT("elf32-i386")
 OUTPUT_ARCH(i386)
 ENTRY(_start)
 
 SECTIONS
 {
-       . = 0;
-       .bstext         : { *(.bstext) }
+       .bstext 0       : { *(.bstext) }
        .bsdata         : { *(.bsdata) }
 
-       . = 497;
-       .header         : { *(.header) }
+       .header 497     : { *(.header) }
        .inittext       : { *(.inittext) }
        .initdata       : { *(.initdata) }
        .text           : { *(.text*) }
@@ -38,16 +36,29 @@ SECTIONS
 
 
        . = ALIGN(16);
-       __bss_start = .;
-       .bss            :
-       {
-               *(.bss)
-       }
-       . = ALIGN(16);
+       .bss ALIGN(16)  : {
+               __bss_start = .;
+                *(.bss)
+               . = ALIGN(16);
+        }
        _end = .;
 
        /DISCARD/ : { *(.note*) }
 
-       . = ASSERT(_end <= 0x8000, "Setup too big!");
-       . = ASSERT(hdr == 0x1f1, "The setup header has the wrong offset!");
+       . = ALIGN(512);         /* align to sector size */
+       _setup_size = . - _start;
+       _setup_sects = _setup_size / 512;
+
+       /* compressed kernel data */
+       .kernel : {
+               kernel = .;
+               *(.kernel)
+               kernel_end = .;
+
+       }
+       kernel_size = kernel_end - kernel;
+       kernel_size_para = (kernel_size + 15) / 16;
 }
+
+ASSERT(_end <= 0x8000, "Setup too big!");
+ASSERT(hdr == 0x1f1, "The setup header has the wrong offset!");
===================================================================
--- a/arch/i386/boot/tools/.gitignore
+++ /dev/null
@@ -1,1 +0,0 @@
-build
===================================================================
--- a/arch/i386/boot/tools/build.c
+++ /dev/null
@@ -1,168 +0,0 @@
-/*
- *  Copyright (C) 1991, 1992  Linus Torvalds
- *  Copyright (C) 1997 Martin Mares
- *  Copyright (C) 2007 H. Peter Anvin
- */
-
-/*
- * This file builds a disk-image from three different files:
- *
- * - setup: 8086 machine code, sets up system parm
- * - system: 80386 code for actual system
- *
- * It does some checking that all files are of the correct type, and
- * just writes the result to stdout, removing headers and padding to
- * the right amount. It also writes some system data to stderr.
- */
-
-/*
- * Changes by tytso to allow root device specification
- * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
- * Cross compiling fixes by Gertjan van Wingerde, July 1996
- * Rewritten by Martin Mares, April 1997
- * Substantially overhauled by H. Peter Anvin, April 2007
- */
-
-#include <stdio.h>
-#include <string.h>
-#include <stdlib.h>
-#include <stdarg.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/sysmacros.h>
-#include <unistd.h>
-#include <fcntl.h>
-#include <sys/mman.h>
-#include <asm/boot.h>
-
-typedef unsigned char  u8;
-typedef unsigned short u16;
-typedef unsigned long  u32;
-
-#define DEFAULT_MAJOR_ROOT 0
-#define DEFAULT_MINOR_ROOT 0
-
-/* Minimal number of setup sectors */
-#define SETUP_SECT_MIN 5
-#define SETUP_SECT_MAX 64
-
-/* This must be large enough to hold the entire setup */
-u8 buf[SETUP_SECT_MAX*512];
-int is_big_kernel;
-
-static void die(const char * str, ...)
-{
-       va_list args;
-       va_start(args, str);
-       vfprintf(stderr, str, args);
-       fputc('\n', stderr);
-       exit(1);
-}
-
-static void usage(void)
-{
-       die("Usage: build [-b] setup system [rootdev] [> image]");
-}
-
-int main(int argc, char ** argv)
-{
-       unsigned int i, sz, setup_sectors;
-       int c;
-       u32 sys_size;
-       u8 major_root, minor_root;
-       struct stat sb;
-       FILE *file;
-       int fd;
-       void *kernel;
-
-       if (argc > 2 && !strcmp(argv[1], "-b"))
-         {
-           is_big_kernel = 1;
-           argc--, argv++;
-         }
-       if ((argc < 3) || (argc > 4))
-               usage();
-       if (argc > 3) {
-               if (!strcmp(argv[3], "CURRENT")) {
-                       if (stat("/", &sb)) {
-                               perror("/");
-                               die("Couldn't stat /");
-                       }
-                       major_root = major(sb.st_dev);
-                       minor_root = minor(sb.st_dev);
-               } else if (strcmp(argv[3], "FLOPPY")) {
-                       if (stat(argv[3], &sb)) {
-                               perror(argv[3]);
-                               die("Couldn't stat root device.");
-                       }
-                       major_root = major(sb.st_rdev);
-                       minor_root = minor(sb.st_rdev);
-               } else {
-                       major_root = 0;
-                       minor_root = 0;
-               }
-       } else {
-               major_root = DEFAULT_MAJOR_ROOT;
-               minor_root = DEFAULT_MINOR_ROOT;
-       }
-       fprintf(stderr, "Root device is (%d, %d)\n", major_root, minor_root);
-
-       /* Copy the setup code */
-       file = fopen(argv[1], "r");
-       if (!file)
-               die("Unable to open `%s': %m", argv[1]);
-       c = fread(buf, 1, sizeof(buf), file);
-       if (ferror(file))
-               die("read-error on `setup'");
-       if (c < 1024)
-               die("The setup must be at least 1024 bytes");
-       if (buf[510] != 0x55 || buf[511] != 0xaa)
-               die("Boot block hasn't got boot flag (0xAA55)");
-       fclose(file);
-
-       /* Pad unused space with zeros */
-       setup_sectors = (c + 511) / 512;
-       if (setup_sectors < SETUP_SECT_MIN)
-               setup_sectors = SETUP_SECT_MIN;
-       i = setup_sectors*512;
-       memset(buf+c, 0, i-c);
-
-       /* Set the default root device */
-       buf[508] = minor_root;
-       buf[509] = major_root;
-
-       fprintf(stderr, "Setup is %d bytes (padded to %d bytes).\n", c, i);
-
-       /* Open and stat the kernel file */
-       fd = open(argv[2], O_RDONLY);
-       if (fd < 0)
-               die("Unable to open `%s': %m", argv[2]);
-       if (fstat(fd, &sb))
-               die("Unable to stat `%s': %m", argv[2]);
-       sz = sb.st_size;
-       fprintf (stderr, "System is %d kB\n", (sz+1023)/1024);
-       kernel = mmap(NULL, sz, PROT_READ, MAP_SHARED, fd, 0);
-       if (kernel == MAP_FAILED)
-               die("Unable to mmap '%s': %m", argv[2]);
-       sys_size = (sz + 15) / 16;
-       if (!is_big_kernel && sys_size > DEF_SYSSIZE)
-               die("System is too big. Try using bzImage or modules.");
-
-       /* Patch the setup code with the appropriate size parameters */
-       buf[0x1f1] = setup_sectors-1;
-       buf[0x1f4] = sys_size;
-       buf[0x1f5] = sys_size >> 8;
-       buf[0x1f6] = sys_size >> 16;
-       buf[0x1f7] = sys_size >> 24;
-
-       if (fwrite(buf, 1, i, stdout) != i)
-               die("Writing setup failed");
-
-       /* Copy the kernel code */
-       if (fwrite(kernel, 1, sz, stdout) != sz)
-               die("Writing kernel failed");
-       close(fd);
-
-       /* Everything is OK */
-       return 0;
-}

-- 


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