Re: [PATCH 1/3] LoongArch: tools: Add relocs tool support

[Youling Tang]

Hi, Ruoyao

On 09/06/2022 01:17 PM, Xi Ruoyao wrote:
> On Tue, 2022-09-06 at 10:16 +0800, Youling Tang wrote:
>
> > Switch to relative exception tables:
> >
> > https://github.com/tangyouling/linux/commit/6525b8da
> > https://github.com/tangyouling/linux/commit/b6ac0827
> >
> > Will switch to the relative exception tables after applying the above
> > two patches. So there is no need to relocate the exception table
> > (remove relocate_exception_table).
> >
> > Now we can remove the relocation of la.abs , got and ex_table, but
> > still need to relocate LARCH_64. Is there anything else that needs to
> > be modified to eliminate this relocation?
>
> You may see the RISC-V patch as a reference:
>
> https://lore.kernel.org/all/20211009171259.2515351-2-alexandre.ghiti@xxxxxxxxxxxxx/
>
> Basically, make the linker to generate R_*_RELATIVE instead of R_*_64
> for pointers.  And, perform R_*_RELATIVE relocation loading the kernel.
>
> Something problematic IMO: RISC-V uses "-shared" to trick the linker to
> generate R_*_RELATIVE but I consider it ugly (if the kernel is a shared
> library, my grandma will be a wagon!)  I prefer "-pie -static", but our
> Glibc does not have static-pie support for now.  It won't really affect
> the kernel (we are -nostdlib), but we cannot learn how to handle
> R_*_RELATIVE in static pie from Glibc then.

After applying all the patches in the link [1], the implementation of 
the relocs tool can now be removed :).

commit: 244fb0971a ... ad45233ef6

[1] https://github.com/tangyouling/loongarch-next/commits/loongarch-next

Youling.