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

From: Youling Tang <tangyouling@loongson.cn>
To: Xi Ruoyao <xry111@xry111.site>, Huacai Chen <chenhuacai@kernel.org>
Cc: Jinyang He <hejinyang@loongson.cn>,
	loongarch@lists.linux.dev, LKML <linux-kernel@vger.kernel.org>,
	WANG Xuerui <kernel@xen0n.name>,
	Lulu Cheng <chenglulu@loongson.cn>
Subject: Re: [PATCH v4 0/4] LoongArch: Support new relocation types
Date: Mon, 1 Aug 2022 20:13:43 +0800	[thread overview]
Message-ID: <3c724516-50eb-cd34-5e4f-399c53a89ee4@loongson.cn> (raw)
In-Reply-To: <d6cab26afc5829c1b93bc1cc5867ebf22f5c7f47.camel@xry111.site>

On 08/01/2022 07:39 PM, Xi Ruoyao wrote:
> On Mon, 2022-08-01 at 19:28 +0800, Youling Tang wrote:
>
>>> Actually, I really hope kernel image is in the XKVRANGE, rather
>>> than being in XKPRANGE. So that we can limit kernel and modules
>>> be in 4GB range. I think it will make all work normally. :-(
>>>
>>
>> Assuming that the kernel and modules are limited to 4G, the external
>> symbols will be accessed through pcrel32, which means that there is no
>> need to pass the GOT table entry and there is no need for got support
>
> We'll still need to modify GCC to use PC-rel for accessing an object in
> another TU (by default, or an option to control), instead of GOT.  Or
> just add support to GOT relocations here.  But anyway it will be much
> easier as we won't need to handle per-CPU variables specially.
>
OO, old toolchains require extra handlingg no matter how modified.
Maybe rejecting old toolchain builds is a good option as Huacai said.

Youling.