Assemble via ELF, to enable future linking

Assemble all files to ELF instead of using the NASM built-in linker.
This can enable us to do actual linking in the future.

13 files changed, 168 insertions, 58 deletions

diff --git a/.gitignore b/.gitignore
index fc5482cc..cd35dd2f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -17,6 +17,7 @@
 *.orig
 *.rej
 *.s
+*.sec
 *.sys
 *_bin.c
 *~
diff --git a/Makefile b/Makefile
index cbdb7b53..e1b71917 100644
--- a/Makefile
+++ b/Makefile
@@ -15,7 +15,8 @@
 #
 
 # No builtin rules
-MAKEFLAGS = -r
+MAKEFLAGS += -r
+MAKE      += -r
 
 TMPFILE = $(shell mktemp /tmp/gcc_ok.XXXXXX)
 
@@ -33,6 +34,9 @@ PIC      = -fPIC
 LDFLAGS  = -O2 -s $(LDHASH)
 AR	 = ar
 RANLIB   = ranlib
+LD	 = ld
+OBJCOPY  = objcopy
+OBJDUMP  = objdump
 
 NASM	 = nasm
 NASMOPT  = -O9999
@@ -145,20 +149,26 @@ version.h: version version.pl
 kwdhash.gen: keywords genhash.pl
 	$(PERL) genhash.pl < keywords > kwdhash.gen
 
+.PRECIOUS: %.elf
+
 # Standard rule for {isolinux,isolinux-debug}.bin
-iso%.bin: iso%.asm kwdhash.gen version.gen
-	$(NASM) $(NASMOPT) -f bin -DDATE_STR="'$(DATE)'" -DHEXDATE="$(HEXDATE)" \
-		-DMAP=$(@:.bin=.map) -l $(@:.bin=.lsr) -o $@ $<
-	$(PERL) lstadjust.pl $(@:.bin=.lsr) $(@:.bin=.map) $(@:.bin=.lst)
+iso%.bin: iso%.elf
+	$(OBJCOPY) -O binary $< $@
 	$(PERL) checksumiso.pl $@
-	$(PERL) checkov.pl $(@:.bin=.map) $@
 
 # Standard rule for {ldlinux,pxelinux,extlinux}.bin
-%.bin: %.asm kwdhash.gen version.gen
-	$(NASM) $(NASMOPT) -f bin -DDATE_STR="'$(DATE)'" -DHEXDATE="$(HEXDATE)" \
-		-DMAP=$(@:.bin=.map) -l $(@:.bin=.lsr) -o $@ $<
-	$(PERL) lstadjust.pl $(@:.bin=.lsr) $(@:.bin=.map) $(@:.bin=.lst)
-	$(PERL) checkov.pl $(@:.bin=.map) $@
+%.bin: %.elf
+	$(OBJCOPY) -O binary $< $@
+
+%.o: %.asm kwdhash.gen version.gen
+	$(NASM) $(NASMOPT) -f elf -F stabs -DDATE_STR="'$(DATE)'" \
+		-DHEXDATE="$(HEXDATE)" \
+		-l $(@:.o=.lsr) -o $@ $<
+
+%.elf: %.o syslinux.ld
+	$(LD) -m elf_i386 -T syslinux.ld -M -o $@ $< > $(@:.elf=.map)
+	$(OBJDUMP) -h $@ > $(@:.elf=.sec)
+	$(PERL) lstadjust.pl $(@:.elf=.lsr) $(@:.elf=.sec) $(@:.elf=.lst)
 
 pxelinux.0: pxelinux.bin
 	cp -f $< $@
@@ -230,13 +240,13 @@ netinstall: installer
 	install -m 644 $(NETINSTALLABLE) $(INSTALLROOT)$(TFTPBOOT)
 
 local-tidy:
-	rm -f *.o *_bin.c stupid.* patch.offset
-	rm -f *.lsr *.lst *.map
+	rm -f *.o *.elf *_bin.c stupid.* patch.offset
+	rm -f *.lsr *.lst *.map *.sec
 	rm -f $(OBSOLETE)
-	$(MAKE) -C gpxe/src veryclean
 
 tidy: local-tidy
 	set -e ; for i in $(BESUBDIRS) $(IESUBDIRS) $(BSUBDIRS) $(ISUBDIRS) ; do $(MAKE) -C $$i $@ ; done
+	$(MAKE) -C gpxe/src veryclean
 
 local-clean:
 	rm -f $(ITARGET)
@@ -258,7 +268,7 @@ spotless: local-clean dist local-spotless
 .depend:
 	rm -f .depend
 	for csrc in $(CSRC) ; do $(CC) $(INCLUDE) -MM $$csrc >> .depend ; done
-	for nsrc in $(NASMSRC) ; do $(NASM) -DDEPEND $(NINCLUDE) -o `echo $$nsrc | sed -e 's/\.asm/\.bin/'` -M $$nsrc >> .depend ; done
+	for nsrc in $(NASMSRC) ; do $(NASM) -DDEPEND $(NINCLUDE) -o `echo $$nsrc | sed -e 's/\.asm/\.o/'` -M $$nsrc >> .depend ; done
 
 local-depend:
 	rm -f .depend
diff --git a/dos/Makefile b/dos/Makefile
index 964c7fdc..04550dab 100644
--- a/dos/Makefile
+++ b/dos/Makefile
@@ -21,7 +21,8 @@ RANLIB   = ranlib
 LIBGCC  := $(shell $(CC) --print-libgcc)
 
 SRCS     = syslinux.c \
-	   ../syslxmod.c ../bootsect_bin.c ../ldlinux_bin.c ../mbr_bin.c \
+	   ../libinstaller/syslxmod.c \
+	   ../bootsect_bin.c ../ldlinux_bin.c ../mbr_bin.c \
            $(wildcard ../libfat/*.c)
 OBJS	 = crt0.o $(patsubst %.c,%.o,$(notdir $(SRCS)))
 LIBOBJS	 = conio.o memcpy.o memset.o  skipatou.o atou.o malloc.o free.o \
diff --git a/extlinux.asm b/extlinux.asm
index 2b43533b..6c2946c2 100644
--- a/extlinux.asm
+++ b/extlinux.asm
@@ -143,7 +143,7 @@ OrigESDI	equ StackBuf-4		; The high dword on the stack
 ; "magic number" (using the term very loosely) for the DOS superblock.
 ;
 bootsec		equ $
-		jmp short start		; 2 bytes
+_start:		jmp short start		; 2 bytes
 		nop			; 1 byte
 ;
 ; "Superblock" follows -- it's in the boot sector, so it's already
diff --git a/extlinux/Makefile b/extlinux/Makefile
index f4267020..88d4d1a9 100644
--- a/extlinux/Makefile
+++ b/extlinux/Makefile
@@ -12,7 +12,8 @@ INCLUDES = -I. -I.. -I../libinstaller
 CFLAGS	 = -W -Wall -Wno-sign-compare -D_FILE_OFFSET_BITS=64 $(OPTFLAGS) $(INCLUDES)
 LDFLAGS	 = $(LDHASH) # -s
 
-SRCS     = extlinux.c setadv.c extlinux_bss_bin.c extlinux_sys_bin.c
+SRCS     = main.c ../libinstaller/setadv.c \
+	   ../extlinux_bss_bin.c ../extlinux_sys_bin.c
 OBJS	 = $(patsubst %.c,%.o,$(notdir $(SRCS)))
 
 .SUFFIXES: .c .o .i .s .S
diff --git a/extlinux/extlinux.c b/extlinux/main.c
index 0edce5a5..0edce5a5 100644
--- a/extlinux/extlinux.c
+++ b/extlinux/main.c
diff --git a/head.inc b/head.inc
index 95a7d193..928f07fb 100644
--- a/head.inc
+++ b/head.inc
@@ -21,10 +21,10 @@
 
 %include "macros.inc"
 %include "config.inc"
+%include "layout.inc"
 %include "kernel.inc"
 %include "bios.inc"
 %include "tracers.inc"
-%include "layout.inc"
 %include "stack.inc"
 
 %endif ; _HEAD_INC
diff --git a/layout.inc b/layout.inc
index c800f1b1..f58ec8fa 100644
--- a/layout.inc
+++ b/layout.inc
@@ -16,6 +16,8 @@
 ; Memory layout of segments
 ;
 
+		; Default to 16-bit code
+		bits 16
 
 ; Memory below 0800h is reserved for the BIOS and the MBR.
 BSS_START	equ 0800h
@@ -28,11 +30,6 @@ TEXT_START	equ 7C00h
 ; but it doesn't seem to work that way.
 LATEBSS_START	equ 0B800h
 
-; Reserve memory for the stack.  This causes checkov to abort the
-; compile if we violate this space.
-STACK_SIZE	equ 4096
-STACK_START	equ TEXT_START-STACK_SIZE
-
 %ifdef MAP
 		[map all MAP]
 %endif
@@ -40,18 +37,16 @@ STACK_START	equ TEXT_START-STACK_SIZE
 ;
 ; The various sections and their relationship
 ;
-		org TEXT_START
-
 		; Use .earlybss for things that MUST be in low memory.
 		section .earlybss	nobits start=BSS_START
-		section .bcopy32	align=4 valign=16 follows=.data vfollows=.earlybss
-		section .config		align=4 valign=16 follows=.bcopy32 vfollows=.bcopy32
-		section .config.end	nobits valign=4 vfollows=.config
+		section .bcopy32	exec nowrite progbits align=4
+		section .config		write progbits align=4
+		section .config.end	write nobits   align=4
 
 		; Use .bss for things that doesn't have to be in low memory;
 		; with .bss1 and .bss2 to offload.  .earlybss should be used
 		; for things that absolutely have to be below 0x7c00.
-		section .bss		nobits valign=16 vfollows=.config.end
+		section .bss		write nobits align=16
 
 		; Warning here: RBFG build 22 randomly overwrites
 		; memory location [0x5680,0x576c), possibly more.  It
@@ -59,37 +54,38 @@ STACK_START	equ TEXT_START-STACK_SIZE
 		; pointer to its own internal packet buffer and starts
 		; writing a received ARP packet into low memory.
 %if IS_PXELINUX
-		section .rbfg		nobits start=0x5680
+		section .rbfg		write nobits
 RBFG_brainfuck:	resb 2048		; Bigger than an Ethernet packet...
 %endif
 
 		; For section following .rbfg
 %if IS_PXELINUX
-		section .bss2		nobits valign=16 vfollows=.rbfg
+		section .bss2		write nobits align=16
 %else
-		section .bss2		nobits valign=16 vfollows=.bss
+		section .bss2		write nobits align=16
 %endif
 
-		section .text		start=TEXT_START
-		; NASM BUG: .data always follows .text; can't override
-		section .data		align=16 ; follows=.text
-
-		; This empty section works around a NASM bug with regards
-		; to follows= and nobits sections following a section which
-		; has VMA != LMA.
-		section .advpad		progbits align=512 follows=.config
+		section .text		exec write progbits align=16
+		section .data		write progbits align=16
 
-		section .adv		nobits align=512 follows=.advpad
+		section .adv		write nobits align=512
 
 		; .uibss contains bss data which is guaranteed to be
 		; safe to clobber during the loading of the image.  This
 		; is because while loading the primary image we will clobber
 		; the spillover from the last fractional sector load.
-		section .uibss		nobits align=16 follows=.adv
+		section .uibss		write nobits align=16
 
 		; Normal bss...
-		section .bss1		nobits align=16 follows=.uibss
+		section .bss1		write nobits align=16
+
+		; Symbols from linker script
+		extern Stack
+		extern section..bcopy32.start
+		extern section..config.start
+		extern section..config.vstart
+		extern section..config.end.start
+
+		global _start
 
-		; Reserve space for stack
-		section .stack		nobits align=16 start=STACK_START
-Stack		resb	STACK_SIZE
+		section .text
diff --git a/ldlinux.asm b/ldlinux.asm
index 012fd3da..86de4588 100644
--- a/ldlinux.asm
+++ b/ldlinux.asm
@@ -151,7 +151,7 @@ OrigESDI	equ StackBuf-4		; The high dword on the stack
 ; "magic number" (using the term very loosely) for the DOS superblock.
 ;
 bootsec		equ $
-		jmp short start		; 2 bytes
+_start:		jmp short start		; 2 bytes
 		nop			; 1 byte
 ;
 ; "Superblock" follows -- it's in the boot sector, so it's already
diff --git a/lstadjust.pl b/lstadjust.pl
index 381c86c3..cec54029 100755
--- a/lstadjust.pl
+++ b/lstadjust.pl
@@ -18,16 +18,10 @@ open(OUT, "> $outfile\0")
     or die "$0: cannot create: $outfile: $!\n";
 
 %vstart = ();
-undef $sec;
 
 while (defined($line = <MAP>)) {
-    chomp $line;
-    if ($line =~ /^\-+\s+Section\s+(\S+)\s+\-/) {
-	$sec = $1;
-    }
-    next unless (defined($sec));
-    if ($line =~ /^vstart:\s+([0-9a-f]+)/i) {
-	$vstart{$sec} = hex $1;
+    if ($line =~ /^\s*([0-9]+)\s+(\S+)\s+([0-9a-f]+)\s+([0-9a-f]+)\s+([0-9a-f]+)\s+([0-9a-f]+)\s+2\*\*([0-9]+)/i) {
+	$vstart{$2} = hex $4;
     }
 }
 close(MAP);
diff --git a/mtools/Makefile b/mtools/Makefile
index 7175bb3f..a53e378f 100644
--- a/mtools/Makefile
+++ b/mtools/Makefile
@@ -12,7 +12,8 @@ INCLUDES = -I. -I.. -I../libfat -I../libinstaller
 CFLAGS	 = -W -Wall -D_FILE_OFFSET_BITS=64 $(OPTFLAGS) $(INCLUDES)
 LDFLAGS	 = $(LDHASH) -s
 
-SRCS     = syslinux.c ../syslxmod.c ../bootsect_bin.c ../ldlinux_bin.c $(wildcard ../libfat/*.c)
+SRCS     = syslinux.c ../syslxmod.c ../bootsect_bin.c ../ldlinux_bin.c \
+	   $(wildcard ../libfat/*.c)
 OBJS	 = $(patsubst %.c,%.o,$(notdir $(SRCS)))
 
 .SUFFIXES: .c .o .i .s .S
diff --git a/syslinux.ld b/syslinux.ld
new file mode 100644
index 00000000..d6fa685d
--- /dev/null
+++ b/syslinux.ld
@@ -0,0 +1,105 @@
+/*
+ * Linker script for the SYSLINUX core
+ */
+
+OUTPUT_FORMAT("elf32-i386", "elf32-i386", "elf32-i386")
+OUTPUT_ARCH(i386)
+EXTERN(_start)
+ENTRY(_start)
+
+STACK_LEN = 4096;
+
+SECTIONS
+{
+	/* "Early" sections (before the load) */
+	. = 0x0800;
+	
+	.earlybss : {
+		__earlybss_start = .;
+		*(.earlybss)
+		__earlybss_len = . - __earlybss_start;
+	}
+
+	.bcopy32 : AT (__bcopy32_lma) {
+		FILL(0x90909090)
+		__bcopy32_start = .;
+		*(.bcopy32)
+		__bcopy32_len = . - __bcopy32_start;
+	}
+
+	.config : AT (__config_lma) {
+		__config_start = .;
+		*(.config)
+		__config_len = . - __config_start;
+	}
+
+	.bss : AT(__bss_start) {
+		__bss_start = .;
+		*(.bss)
+		*(.bss2)
+		__bss_len = . - __bss_start;
+	}
+
+	/* Stack */
+
+	. = 0x7c00 - STACK_LEN;
+	.stack : {
+		__stack_start = .;
+		. += STACK_LEN;
+		__stack_len = . - __stack_start;
+	}
+
+	/* Initialized sections */
+
+	. = 0x7c00;
+	.text : {
+		FILL(0x90909090)
+		__text_start = .;
+		*(.text)
+		__text_len = . - __text_start;
+	}
+
+	. = ALIGN(4);
+	__bcopy32_lma = .;
+	. += SIZEOF(.bcopy32);
+
+	. = ALIGN(4);
+	.data : {
+	      __data_start = .;
+	      *(.data)
+	      __data_len = . - __data_start;
+	}
+
+	. = ALIGN(4);
+	__config_lma = .;
+	. += SIZEOF(.config);
+
+	/* ADV, must be the last intialized section */
+
+	. = ALIGN(512);
+	.adv : {
+		__adv_start = .;
+		*(.adv)
+		__adv_len = . - __adv_start;
+	}
+
+	/* Late uninitialized sections */
+
+	.uibss : {
+		__uibss_start = .;
+		*(.uibss)
+		__uibss_len = . - __uibss_start;
+	}
+
+	.bss1 : {
+		__bss1_start = .;
+		*(.bss1)
+		__bss1_len = . - __bss1_start;
+	}
+
+	Stack			  = __stack_start;
+	section..bcopy32.start    = __bcopy32_lma;
+	section..config.start     = __config_lma;
+	section..config.vstart    = __config_start;
+	section..config.end.start = __config_start + SIZEOF(.config);
+}
diff --git a/unix/Makefile b/unix/Makefile
index 8d92d3a2..07f97d67 100644
--- a/unix/Makefile
+++ b/unix/Makefile
@@ -12,7 +12,8 @@ INCLUDES = -I. -I.. -I../libinstaller
 CFLAGS	 = -W -Wall -D_FILE_OFFSET_BITS=64 $(OPTFLAGS) $(INCLUDES)
 LDFLAGS	 = $(LDHASH) -s
 
-SRCS     = syslinux.c ../syslxmod.c ../bootsect_bin.c ../ldlinux_bin.c
+SRCS     = syslinux.c ../libinstaller/syslxmod.c \
+	   ../bootsect_bin.c ../ldlinux_bin.c
 OBJS	 = $(patsubst %.c,%.o,$(notdir $(SRCS)))
 
 .SUFFIXES: .c .o .i .s .S