From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=209.85.128.51; helo=mail-wm1-f51.google.com; envelope-from=philmd@redhat.com; receiver=edk2-devel@lists.01.org Received: from mail-wm1-f51.google.com (mail-wm1-f51.google.com [209.85.128.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 2EA4121161206 for ; Mon, 1 Oct 2018 03:26:37 -0700 (PDT) Received: by mail-wm1-f51.google.com with SMTP id 143-v6so279411wmf.1 for ; Mon, 01 Oct 2018 03:26:37 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=RXwupTjo71FObC8jEQ24yeStGy5RJA9Q8oi1limkGsQ=; b=opDrRe+0jqf1kDTKyCf916AQMXDd184qdg60ldOx69j8JSkAWc6Av6+xlamh/jkcLH 81bpl1ZhpjU8POF4EwBpBTtvLEgnp+hUy+xxyCXMIPWpSwXtbsjh2kG/mabW/Mu6G18D SeXb2POdh+2BCk7XJClBq0lh2+QBHwWGC6O4pomAnguASipxljXrbCroQFXK+25RlwmF D/y/CtO7HckHmXqAZfHjaHE9Aq00tYgd30D14/c6n0ds3tES5jZ3ucB6CNSqXdava6Bx 27AvqhyvIydGyE6lNAIyk5lHcog9x/CAgM073Yyg8GDhLP6Vs3VEetd+TqDhu56isRLL QWhQ== X-Gm-Message-State: ABuFfogJhDd6rVbkZQAybq1bSdNm/vTLjpxPPcg2uwp1U57Pk3uvJIa6 r8817FR7vxzEzuR9fd2Z3r6dNw== X-Google-Smtp-Source: ACcGV63cUO1je26hcW62RNE+JnzqqDpuWDR0b72z2vq10mmQaoMhYdQ2lHcbSMfCwlmmHWqz/WZkew== X-Received: by 2002:a1c:5801:: with SMTP id m1-v6mr2517601wmb.118.1538389595539; Mon, 01 Oct 2018 03:26:35 -0700 (PDT) Received: from [192.168.2.71] ([80.31.72.241]) by smtp.gmail.com with ESMTPSA id v16-v6sm20574746wrw.12.2018.10.01.03.26.34 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 01 Oct 2018 03:26:34 -0700 (PDT) To: Laszlo Ersek , edk2-devel-01 Cc: Michael D Kinney , Liming Gao References: <20180929222312.32150-1-lersek@redhat.com> <20180929222312.32150-3-lersek@redhat.com> From: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= Message-ID: <5569bc63-1ebd-80f8-f5c9-83ab32d76b6e@redhat.com> Date: Mon, 1 Oct 2018 12:26:33 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.0 MIME-Version: 1.0 In-Reply-To: <20180929222312.32150-3-lersek@redhat.com> Subject: Re: [PATCH 2/5] MdePkg/BaseSynchronizationLib GCC: fix InternalSyncCompareExchange16() X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 01 Oct 2018 10:26:37 -0000 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit On 30/09/2018 00:23, Laszlo Ersek wrote: > The CMPXCHG instruction has the following operands: > - AX (implicit, CompareValue): input and output > - destination operand (*Value): input and output > - source operand (ExchangeValue): input > > The IA32 version of InternalSyncCompareExchange16() correctly marks > CompareValue as input/output, but it marks (*Value) only as input. > > The X64 version of InternalSyncCompareExchange16() attempts to mark both > CompareValue and (*Value) as input/output, but it doesn't use the > appropriate constraints for either operand. > > Fix these issues. Furthermore, prefer the short "+" constraint for I/O > operands over the constraint that can be applied > to the input instances of I/O operands. > > Cc: Liming Gao > Cc: Michael D Kinney > Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1208 > Contributed-under: TianoCore Contribution Agreement 1.1 > Signed-off-by: Laszlo Ersek Reviewed-by: Philippe Mathieu-Daudé > --- > MdePkg/Library/BaseSynchronizationLib/Ia32/GccInline.c | 9 ++++----- > MdePkg/Library/BaseSynchronizationLib/X64/GccInline.c | 10 ++++------ > 2 files changed, 8 insertions(+), 11 deletions(-) > > diff --git a/MdePkg/Library/BaseSynchronizationLib/Ia32/GccInline.c b/MdePkg/Library/BaseSynchronizationLib/Ia32/GccInline.c > index 1976720ac636..bd98a5aebfe7 100644 > --- a/MdePkg/Library/BaseSynchronizationLib/Ia32/GccInline.c > +++ b/MdePkg/Library/BaseSynchronizationLib/Ia32/GccInline.c > @@ -115,11 +115,10 @@ InternalSyncCompareExchange16 ( > { > __asm__ __volatile__ ( > "lock \n\t" > - "cmpxchgw %1, %2 \n\t" > - : "=a" (CompareValue) // %0 > - : "q" (ExchangeValue), // %1 > - "m" (*Value), // %2 > - "0" (CompareValue) // %3 > + "cmpxchgw %2, %1 \n\t" > + : "+a" (CompareValue), // %0 > + "+m" (*Value) // %1 > + : "q" (ExchangeValue) // %2 > : "memory", > "cc" > ); > diff --git a/MdePkg/Library/BaseSynchronizationLib/X64/GccInline.c b/MdePkg/Library/BaseSynchronizationLib/X64/GccInline.c > index 0212798d7a27..4338fb8e65e8 100644 > --- a/MdePkg/Library/BaseSynchronizationLib/X64/GccInline.c > +++ b/MdePkg/Library/BaseSynchronizationLib/X64/GccInline.c > @@ -115,12 +115,10 @@ InternalSyncCompareExchange16 ( > { > __asm__ __volatile__ ( > "lock \n\t" > - "cmpxchgw %3, %1 \n\t" > - : "=a" (CompareValue), // %0 > - "=m" (*Value) // %1 > - : "a" (CompareValue), // %2 > - "r" (ExchangeValue), // %3 > - "m" (*Value) // %4 > + "cmpxchgw %2, %1 \n\t" > + : "+a" (CompareValue), // %0 > + "+m" (*Value) // %1 > + : "r" (ExchangeValue) // %2 > : "memory", > "cc" > ); >