Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:18 as permitted sender) client-ip=2620:137:e000::1:18;
Message-ID: <99acc7d2-a11b-250b-f614-18077fb76cc0@huawei.com>
Date:   Wed, 6 Apr 2022 18:02:15 +0800
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101
 Thunderbird/91.6.1
Subject: Re: [RFC PATCH -next V2 1/7] x86: fix copy_mc_to_user compile error
To:     Borislav Petkov <bp@alien8.de>
CC:     Andrew Morton <akpm@linux-foundation.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>, <x86@kernel.org>,
        "H. Peter Anvin" <hpa@zytor.com>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>
References: <20220406091311.3354723-1-tongtiangen@huawei.com>
 <20220406091311.3354723-2-tongtiangen@huawei.com> <Yk1bu88TcjXw/iU4@zn.tnic>
From:   Tong Tiangen <tongtiangen@huawei.com>
In-Reply-To: <Yk1bu88TcjXw/iU4@zn.tnic>
Content-Type: text/plain; charset="UTF-8"; format=flowed
Content-Transfer-Encoding: 8bit
Precedence: bulk


在 2022/4/6 17:22, Borislav Petkov 写道:
> On Wed, Apr 06, 2022 at 09:13:05AM +0000, Tong Tiangen wrote:
>> The follow patch
> 
> There's no concept of "follow patch" in git - you need to explain this
> differently.
> 
>> will add copy_mc_to_user to include/linux/uaccess.h, X86
>> must declare Implemented to avoid compile error.
> 
> I don't know what that means. Try again pls.
> 

This description is not good, will redescribe it in next version.

Here I describe the reasons for this:

Patch 3/7 in patchset[1] introduce copy_mc_to_user() in 
include/linux/uaccess.h and the prototype is:

     static inline unsigned long __must_check
     copy_mc_to_user(void *dst, const void *src, size_t cnt)

The prototype in x86 is:

     unsigned long __must_check
     copy_mc_to_user(void *to, const void *from, unsigned len);

This two are a little different, so I added the follow code to x86 to
avoid prototype conflict compile error.

     #define copy_mc_to_user copy_mc_to_user

In addition, I think this #define should be added here.

[1]https://patchwork.kernel.org/project/linux-mm/cover/20220406091311.3354723-1-tongtiangen@huawei.com/

Thanks.
Tong.