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;
Subject: Re: [RFC PATCH v3 3/3] LoongArch: No need to call RESTORE_ALL_AND_RET
 for all syscalls
To:     Huacai Chen <chenhuacai@kernel.org>
References: <1655288973-6066-1-git-send-email-yangtiezhu@loongson.cn>
 <1655288973-6066-4-git-send-email-yangtiezhu@loongson.cn>
 <CAAhV-H7ULiOUP-7RfLvQb2mOKt7NtqKUxipkfXdbkPGgzEptrQ@mail.gmail.com>
Cc:     WANG Xuerui <kernel@xen0n.name>,
        Xuefeng Li <lixuefeng@loongson.cn>,
        Jianmin Lv <lvjianmin@loongson.cn>, Jun Yi <yijun@loongson.cn>,
        Rui Wang <wangrui@loongson.cn>,
        LKML <linux-kernel@vger.kernel.org>
From:   Tiezhu Yang <yangtiezhu@loongson.cn>
Message-ID: <8ca2304f-37ac-131c-1564-1aede2a47b74@loongson.cn>
Date:   Thu, 16 Jun 2022 21:36:50 +0800
User-Agent: Mozilla/5.0 (X11; Linux mips64; rv:45.0) Gecko/20100101
 Thunderbird/45.4.0
MIME-Version: 1.0
In-Reply-To: <CAAhV-H7ULiOUP-7RfLvQb2mOKt7NtqKUxipkfXdbkPGgzEptrQ@mail.gmail.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk


On 06/16/2022 08:52 PM, Huacai Chen wrote:
> Hi, Tiezhu,
>
> On Wed, Jun 15, 2022 at 6:29 PM Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
>>
>> In handle_syscall, it is unnecessary to call RESTORE_ALL_AND_RET
>> for all syscalls.
>>
>> (1) clone and clone3 call RESTORE_STATIC_SOME_SP_AND_RET.
>> (2) rt_sigreturn and rt_sigsuspend call RESTORE_TEMP_SOME_SP_AND_RET.
> I doubt that you have not tested, it is obvious that rt_sigreturn need
> RESTORE_ALL.

Yes, your guess is right. :)

I have no workable machine to update the upstream kernel now, only 
compile test.

I will try my best to find a workable machine and then test it,
there is a good test case written by Rui Wang [1].

This patch is RFC, any comments will be much appreciated, thank you.

[1] https://github.com/hevz/sigaction-test

Thanks,
Tiezhu