OSDev.org

Hey everyone,

Been a while sense I've been able to check this site, as work's been crazy-busy.

I did, however, just manage to build myself a new AMD64 system, but I'm having difficulties building my OS now!

I've changed my ant build scripts to force gcc to compile 32-bit code (appended the -m32 -oformat=elf32-i386 params).

ld, however, refuses to accept my nasm build start.obj file. I don't understand this. I've checked all my objects and they are correctly elf32-i386 format (objdump --file-headers). ld doesn't complain about any other nasm built objects, either.

The only thing that's different about this particular object is the exact code in it, as far as I can tell.

Can anybody suggest to me why ld doesn't like this file?

I've provided the source, in case anybody would like to look at it.

Thanks,
Jeff

1: could you please give the error message?
2: i hope your includes contain no code

Yes, of course! Sorry

Below is the verbose output. And yes, the include file is merely a bunch of build-time generated %define statements.

--Jeff

link:
[ld] Creating linker script: built/bin/ldscript
[ld] ld -nostdlib -nostartfiles -b elf32-i386 --oformat elf32-i386 --verbose -T built/bin/ldscript -o built/bin/ndk.i386.kernel
[null] ld: skipping incompatible built/obj/arch/i386/start.o when searching for built/obj/arch/i386/start.o
[null] ld: cannot find built/obj/arch/i386/start.o
[null] GNU ld version 2.17.50.0.5 20060927 (SUSE Linux)
[null] Supported emulations:
[null] elf_x86_64
[null] elf_i386
[null] i386linux
[null] elf64alpha
[null] alpha
[null] armelf_linux
[null] armelf
[null] hppalinux
[null] elf64_ia64
[null] m68kelf
[null] m68klinux
[null] elf32ppclinux
[null] elf32ppc
[null] elf32ppcsim
[null] elf64ppc
[null] elf_s390
[null] elf64_s390
[null] elf32_sparc
[null] sparclinux
[null] elf64_sparc
[null] sun4
[null] i386pe
[null] opened script file built/bin/ldscript
[null] using external linker script:
[null] ==================================================
[null] INPUT(built/obj/arch/i386/start.o)
[null] INPUT(built/obj/arch/i386/arch.o)
[null] INPUT(built/obj/arch/i386/console.o)
[null] INPUT(built/obj/arch/i386/descgate.o)
[null] INPUT(built/obj/arch/i386/gdt.o)
[null] INPUT(built/obj/arch/i386/idt.o)
[null] INPUT(built/obj/arch/i386/io.o)
[null] INPUT(built/obj/arch/i386/isr.o)
[null] INPUT(built/obj/arch/i386/memory.o)
[null] INPUT(built/obj/arch/i386/multiboot.o)
[null] INPUT(built/obj/arch/i386/pager.o)
[null] INPUT(built/obj/arch/i386/pic.o)
[null] INPUT(built/obj/arch/i386/pmode.o)
[null] INPUT(built/obj/arch/i386/system.o)
[null] INPUT(built/obj/arch/i386/task.o)
[null] INPUT(built/obj/arch/i386/timer.o)
[null] INPUT(built/obj/arch/i386/vm86.o)
[null] INPUT(built/obj/arch/i386/vm86asm.o)
[null] INPUT(built/obj/appInterface.o)
[null] INPUT(built/obj/array.o)
[null] INPUT(built/obj/binaryTree.o)
[null] INPUT(built/obj/debug.o)
[null] INPUT(built/obj/driver.o)
[null] INPUT(built/obj/expandingQueue.o)
[null] INPUT(built/obj/hashTable.o)
[null] INPUT(built/obj/list.o)
[null] INPUT(built/obj/messageQueue.o)
[null] INPUT(built/obj/mutex.o)
[null] INPUT(built/obj/ndk.o)
[null] INPUT(built/obj/object.o)
[null] INPUT(built/obj/objectKernel.o)
[null] INPUT(built/obj/objectRDOFF2.o)
[null] INPUT(built/obj/queue.o)
[null] INPUT(built/obj/rZero.o)
[null] INPUT(built/obj/semaphore.o)
[null] INPUT(built/obj/stack.o)
[null] INPUT(built/obj/tests/tests.o)
[null] INPUT(built/obj/tests/testsBTree.o)
[null] INPUT(built/obj/tests/testsDriverManager.o)
[null] INPUT(built/obj/tests/testsMutex.o)
[null] INPUT(built/obj/klibc/assert.o)
[null] INPUT(built/obj/klibc/ctype.o)
[null] INPUT(built/obj/klibc/errno.o)
[null] INPUT(built/obj/klibc/fprintf.o)
[null] INPUT(built/obj/klibc/malloc.o)
[null] INPUT(built/obj/klibc/printf.o)
[null] INPUT(built/obj/klibc/sbrk.o)
[null] INPUT(built/obj/klibc/string.o)
[null] INPUT(built/obj/klibc/sysconf.o)
[null] SECTIONS {
[null] .text 0x00100000 :{
[null] *(.text)
[null] }
[null] textEnd = .;

[null] .data :{
[null] *(.data)
[null] *(.rodata)
[null] }
[null] dataEnd = .;

[null] .bss :{
[null] *(.common)
[null] *(.bss)
[null] }
[null] bssEnd = .;
[null] }
[null] ==================================================
[null] attempt to open built/obj/arch/i386/start.o succeeded

BUILD FAILED
/home/dcipher/osDev/ndk/build.xml:355: null returned: 1

CarbonBased wrote:start.obj

ld wrote:ld: cannot find (...)/start.o

typo?

[null] GNU ld version 2.17.50.0.5 20060927 (SUSE Linux)

you are trying to force 32-bit apps out of a 64-bit toolchain? elf32-i386 is NOT listed and it might be that it chokes on the first file in the list then quits before even trying the rest...
If you are indeed running a 64 bit linux, you should definately get a crosscompiler as you are essentially targeting a different architecture.

Combuster wrote:

CarbonBased wrote:start.obj

ld wrote:ld: cannot find (...)/start.o

typo?

Yeah, the obj was a typo -- you've got good eyes!

Combuster wrote:

[null] GNU ld version 2.17.50.0.5 20060927 (SUSE Linux)

you are trying to force 32-bit apps out of a 64-bit toolchain? elf32-i386 is NOT listed and it might be that it chokes on the first file in the list then quits before even trying the rest...

Hmm... yes, you're right. I re-ordered the objects and now another one fails. Should've thought of that first.

I made an assumption that elf_i386 would be compatible with elf32-i386. It appears as though it's not the case. I'm curious as to what the distinction between the two formats is (?).

Combuster wrote: If you are indeed running a 64 bit linux, you should definately get a crosscompiler as you are essentially targeting a different architecture.

Fair enough, will do.

EDIT: Done, worked like a charm, of course.
For those that might be interested, Buenos hosts a good quick tutorial on writting cross compilers. I've used it in the past to build several:

http://www.niksula.hut.fi/~buenos/cross-compiler.html

Only thing I've changed is the addition of --disable-libssp when configuring GCC.

Thanks,
Jeff

carbonBased wrote:For those that might be interested, Buenos hosts a good quick tutorial on writting cross compilers. I've used it in the past to build several:

Basically the same we have in http://www.osdev.org/wiki/GCC_Cross-Compiler, but we also have http://www.osdev.org/wiki/GCC_Cross-Compiler_for_x86_64 and http://www.osdev.org/wiki/GCC_Cross-Compiler_on_Linux. If you find an "integrated" way of adding a cross-compiler to a SuSE setup, you're very welcome to edit the last from that list.