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Subject: Re: [PATCH v4 0/4] LoongArch: Support new relocation types
From: Xi Ruoyao <xry111@xry111.site>
To: Youling Tang <tangyouling@loongson.cn>, loongarch@lists.linux.dev
Cc: linux-kernel@vger.kernel.org, WANG Xuerui <kernel@xen0n.name>, Huacai
 Chen <chenhuacai@kernel.org>, Jinyang He <hejinyang@loongson.cn>, Lulu
 Cheng <chenglulu@loongson.cn>
Date: Sat, 30 Jul 2022 10:24:19 +0800
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On Sat, 2022-07-30 at 01:55 +0800, Xi Ruoyao wrote:
> On Fri, 2022-07-29 at 20:19 +0800, Youling Tang wrote:
>=20
> > 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.=C2=A0 So we can't just load such an
> > > offset
> > > with PCALA addressing.
> > >=20
> > > 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.
>=20
> > Yes, we need a GCC attribute to specify the per-cpu variable.
>=20
> GCC patch adding "addr_global" attribute for LoongArch:
> https://gcc.gnu.org/pipermail/gcc-patches/2022-July/599064.html
>=20
> 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.

--=20
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University