Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <78a4a6b0970c309daa336a2329e69d28df486552.camel@xry111.site>
Subject: Re: [PATCH 1/3] LoongArch: tools: Add relocs tool support
From:   Xi Ruoyao <xry111@xry111.site>
To:     Youling Tang <tangyouling@loongson.cn>,
        Huacai Chen <chenhuacai@kernel.org>
Cc:     linux-kernel@vger.kernel.org, loongarch@lists.linux.dev,
        Xuerui Wang <kernel@xen0n.name>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>,
        Jinyang He <hejinyang@loongson.cn>
Date:   Sat, 03 Sep 2022 18:49:14 +0800
In-Reply-To: <f0e77716-9533-724a-2ea9-86bc5b52066c@loongson.cn>
References: <1662113335-14282-1-git-send-email-tangyouling@loongson.cn>
         <1662113335-14282-2-git-send-email-tangyouling@loongson.cn>
         <c9880165f0355fc3be3ec23153b43ad33e558b5d.camel@xry111.site>
         <4df8a26c49a35c1fce36d80c370f738fa71a2bef.camel@xry111.site>
         <f0e77716-9533-724a-2ea9-86bc5b52066c@loongson.cn>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
User-Agent: Evolution 3.45.2 
MIME-Version: 1.0
Precedence: bulk

On Sat, 2022-09-03 at 09:57 +0800, Youling Tang wrote:
> > > Unlike (pre-r6) MIPS, LoongArch has a complete support for PIC, and
> > > currently LoongArch toolchain always produces PIC (except, if -Wa,-ml=
a-
> > > {local,global}-with-abs or la.abs macros are used explicitly).
> > >=20
> > > So would it be easier to review and correct the uses of "la.abs" in t=
he
> > > code, and make the main kernel image a real PIE?=C2=A0 Then we can lo=
ad it
> > > everywhere w/o any need to do relocation at load time.
>=20
> At the beginning I also wanted to make the main kernel image a real PIE
> and tried it, some of the "la.abs" can be modified, but I encountered
> difficulties in modifying the=C2=A0 exception handling code part, the ker=
nel
> will not=C2=A0 boot after modification :(, I will continue to work hard t=
ry.

I just tried the same thing and get the same result :(.  Will spend
several hours reading the LoongArch manual about exception...

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