Re: [PATCH v4 0/4] LoongArch: Support new relocation types

From: Xi Ruoyao
Date: Fri Jul 29 2022 - 22:24:36 EST


On Sat, 2022-07-30 at 01:55 +0800, Xi Ruoyao wrote:
> On Fri, 2022-07-29 at 20:19 +0800, Youling Tang wrote:
>
> > On 07/29/2022 07:45 PM, Xi Ruoyao wrote:
> > > Hmm... The problem is the "addresses" of per-cpu symbols are
> > > faked: they
> > > are actually offsets from $r21.  So we can't just load such an
> > > offset
> > > with PCALA addressing.
> > >
> > > It looks like we'll need to introduce an attribute for GCC to make
> > > an
> > > variable "must be addressed via GOT", and add the attribute into
> > > PER_CPU_ATTRIBUTES.
>
> > Yes, we need a GCC attribute to specify the per-cpu variable.
>
> GCC patch adding "addr_global" attribute for LoongArch:
> https://gcc.gnu.org/pipermail/gcc-patches/2022-July/599064.html
>
> An experiment to use it:
> https://github.com/xry111/linux/commit/c1d5d70

Correction: https://github.com/xry111/linux/commit/c1d5d708

It seems 7-bit SHA is not enough for kernel repo.

--
Xi Ruoyao <xry111@xxxxxxxxxxx>
School of Aerospace Science and Technology, Xidian University