[PATCH 3/9] i386: clean up bzImage generation

From: Jeremy Fitzhardinge
Date: Wed Jun 20 2007 - 20:38:34 EST

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.

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.lds | 3
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 -------------------------------
arch/x86_64/boot/compressed/Makefile | 12 --
arch/x86_64/boot/compressed/piggy.S | 10 +
arch/x86_64/boot/compressed/vmlinux.lds | 2
arch/x86_64/boot/compressed/vmlinux.scr | 10 -
14 files changed, 73 insertions(+), 244 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.lds
+++ b/arch/i386/boot/compressed/vmlinux.lds
@@ -1,4 +1,4 @@ OUTPUT_FORMAT("elf32-i386", "elf32-i386"
-OUTPUT_FORMAT("elf32-i386", "elf32-i386", "elf32-i386")
+OUTPUT_FORMAT("elf32-i386")
OUTPUT_ARCH(i386)
ENTRY(startup_32)
SECTIONS
@@ -38,6 +38,7 @@ SECTIONS
*(.bss)
*(.bss.*)
*(COMMON)
+ . = ALIGN(8);
_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
===================================================================
--- /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;
-}
===================================================================
--- a/arch/x86_64/boot/compressed/Makefile
+++ b/arch/x86_64/boot/compressed/Makefile
@@ -6,7 +6,7 @@
# Note all the files here are compiled/linked as 32bit executables.
#

-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

CFLAGS := -m64 -D__KERNEL__ $(LINUXINCLUDE) -O2 \
-fno-strict-aliasing -fPIC -mcmodel=small \
@@ -15,8 +15,8 @@ AFLAGS := $(CFLAGS) -D__ASSEMBLY__
AFLAGS := $(CFLAGS) -D__ASSEMBLY__
LDFLAGS := -m elf_x86_64

-LDFLAGS_vmlinux := -T
-$(obj)/vmlinux: $(src)/vmlinux.lds $(obj)/head.o $(obj)/misc.o $(obj)/piggy.o FORCE
+LDFLAGS_blob := -T
+$(obj)/blob: $(src)/vmlinux.lds $(obj)/head.o $(obj)/misc.o $(obj)/piggy.o FORCE
$(call if_changed,ld)
@:

@@ -26,7 +26,5 @@ LDFLAGS_vmlinux := -T
$(obj)/vmlinux.bin.gz: $(obj)/vmlinux.bin FORCE
$(call if_changed,gzip)

-LDFLAGS_piggy.o := -r --format binary --oformat elf64-x86-64 -T
-
-$(obj)/piggy.o: $(obj)/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/x86_64/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/x86_64/boot/compressed/vmlinux.lds
+++ b/arch/x86_64/boot/compressed/vmlinux.lds
@@ -1,4 +1,4 @@ OUTPUT_FORMAT("elf64-x86-64", "elf64-x86
-OUTPUT_FORMAT("elf64-x86-64", "elf64-x86-64", "elf64-x86-64")
+OUTPUT_FORMAT("elf64-x86-64")
OUTPUT_ARCH(i386:x86-64)
ENTRY(startup_64)
SECTIONS
===================================================================
--- a/arch/x86_64/boot/compressed/vmlinux.scr
+++ /dev/null
@@ -1,10 +0,0 @@
-SECTIONS
-{
- .text.compressed : {
- input_len = .;
- LONG(input_data_end - input_data) input_data = .;
- *(.data)
- output_len = . - 4;
- input_data_end = .;
- }
-}

--

-
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