Re: Link failure with Debian toolchain

[Stafford Horne <shorne@gmail.com>]

Hi Joel,

On Thu, May 26, 2022 at 11:26:45PM +0000, Joel Stanley wrote:
> Hi Stafford,
> 
> I'm not sure if you were aware, but Debian now has a or1k cross compile:
> 
> $ apt policy gcc-or1k-elf
> gcc-or1k-elf:
>   Installed: 12.1.0-2+1.0.2
> $ apt policy binutils-or1k-elf
> binutils-or1k-elf:
>   Installed: 2.38-2+1.0.3

I didn't know about this. but it looks right.

> I've used it to build a mork1x litex soc so I think it works in some
> situations at least.
> 
> I was trying to build your latest Linux kernel changes, applied on top
> of v5.18, however the bug reproduces with plain v5.18.
> 
> $ CROSS_COMPILE=or1k-elf- ARCH=openrisc make O=or1k or1klitex_defconfig
> $ CROSS_COMPILE=or1k-elf- ARCH=openrisc make O=or1k -j8

This looks good too. What is the meaning of O=or1k? I never have used that
before.

> This fails at the link step:
> 
>   LD      vmlinux.o
> + or1k-elf-ld -r -o vmlinux.o --whole-archive
> arch/openrisc/kernel/head.o init/built-in.a usr/built-in.a
> arch/openrisc/built-in.a kernel/built-in.a certs/built-in.a
> mm/built-in.a fs/built-in.a ipc/built-in.a security/built-in.a
> crypto/built-in.a block/built-in.a lib/built-in.a drivers/built-in.a
> sound/built-in.a net/built-in.a virt/built-in.a --no-whole-archive
> --start-group lib/lib.a /usr/lib/gcc/or1k-elf/12/libgcc.a --end-group
> or1k-elf-ld: /usr/lib/gcc/or1k-elf/12/libgcc.a: error adding symbols:
> archive has no index; run ranlib to add one
> 
> The libgcc.a appears to have the expected files inside it.
> 
> I tried running ar -a libgcc.a, and that changed the error to look like this:
> 
> or1k-elf-ld: init/main.o: in function `do_one_initcall':
> main.c:(.init.text+0x12ec): undefined reference to `__muldi3'
> main.c:(.init.text+0x12ec): relocation truncated to fit:
> R_OR1K_INSN_REL_26 against undefined symbol `__muldi3'
> 
> With a lot more undefined reference errors for __muldi3, __ashldi3,
> and __lshrdi3.

This seems to mean that the builtins for 64-bit ops are not being found. So
something is wrong with libgcc symbols.  Maybe something strange with the
multilib args used when building the toolchain.

I'll have a look at it. It would be nice if I can used this toolchain for my CI.

-Stafford
> I'm not sure if this is a toolchain error or a kernel one. The kernel
> appears to be doing the right thing.
> 
> I've cc'd Nicholas who is the Debian maintainer for the package in
> case he has any ideas.
> 
> Cheers,
> 
> Joel