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: <64955942-274c-047d-aab3-308fbbe6dfbc@xen0n.name>
Date:   Sat, 24 Jun 2023 01:06:59 +0800
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.12.0
Subject: Re: [PATCH 7/9] LoongArch: Tweak CFLAGS for Clang compatibility
Content-Language: en-US
To:     Xi Ruoyao <xry111@xry111.site>, Huacai Chen <chenhuacai@kernel.org>
Cc:     WANG Rui <wangrui@loongson.cn>, loongarch@lists.linux.dev,
        linux-kbuild@vger.kernel.org, llvm@lists.linux.dev,
        linux-kernel@vger.kernel.org, WANG Xuerui <git@xen0n.name>
References: <20230623134351.1898379-1-kernel@xen0n.name>
 <20230623134351.1898379-8-kernel@xen0n.name>
 <22d794613f70b04544e39e8861737af09365ae8a.camel@xry111.site>
From:   WANG Xuerui <kernel@xen0n.name>
In-Reply-To: <22d794613f70b04544e39e8861737af09365ae8a.camel@xry111.site>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Precedence: bulk

On 6/24/23 01:00, Xi Ruoyao wrote:
> On Fri, 2023-06-23 at 21:43 +0800, WANG Xuerui wrote:
>
>> -cflags-y                       += -G0 -pipe -msoft-float
> -msoft-float should not be removed.  Our consensus (made when I was
> developing https://gcc.gnu.org/r13-6500) is -mabi=lp64s does *not*
> disable floating point instructions, but only disable FPRs for passing
> arguments and return values.  So w/o -msoft-float (or -mfpu=none) GCC is
> allowed to generate FP instructions everywhere in kernel and it may
> cause kernel FPD exception in the future.
Hmm, now I remember (still vaguely) about the discussion... I'll have to 
check how to minimize churn around FPU-touching code though if 
-msoft-float is to be kept.

-- 
WANG "xen0n" Xuerui

Linux/LoongArch mailing list: https://lore.kernel.org/loongarch/