From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <hpa@linux.intel.com>
Received: from mga11.intel.com (mga11.intel.com [192.55.52.93])
 by dpdk.org (Postfix) with ESMTP id AC8334C6E
 for <dev@dpdk.org>; Fri, 21 Mar 2014 16:03:40 +0100 (CET)
Received: from fmsmga002.fm.intel.com ([10.253.24.26])
 by fmsmga102.fm.intel.com with ESMTP; 21 Mar 2014 08:05:11 -0700
X-ExtLoop1: 1
X-IronPort-AV: E=Sophos;i="4.97,704,1389772800"; d="scan'208";a="503842487"
Received: from unknown (HELO hanvin-mobl6.amr.corp.intel.com) ([10.255.40.21])
 by fmsmga002.fm.intel.com with ESMTP; 21 Mar 2014 08:03:34 -0700
Message-ID: <532C54C6.2060202@linux.intel.com>
Date: Fri, 21 Mar 2014 08:03:34 -0700
From: "H. Peter Anvin" <hpa@linux.intel.com>
User-Agent: Mozilla/5.0 (X11; Linux x86_64;
 rv:24.0) Gecko/20100101 Thunderbird/24.3.0
MIME-Version: 1.0
To: Neil Horman <nhorman@tuxdriver.com>, dev@dpdk.org
References: <20140320163921.GC7721@hmsreliant.think-freely.org>
 <1395413340-27392-1-git-send-email-nhorman@tuxdriver.com>
In-Reply-To: <1395413340-27392-1-git-send-email-nhorman@tuxdriver.com>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Subject: Re: [dpdk-dev] [PATCH v2] eal_common_cpuflags: Fix %rbx corruption,
 and simplify the code
X-BeenThere: dev@dpdk.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: patches and discussions about DPDK <dev.dpdk.org>
List-Unsubscribe: <http://dpdk.org/ml/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://dpdk.org/ml/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <http://dpdk.org/ml/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
X-List-Received-Date: Fri, 21 Mar 2014 15:03:41 -0000

On 03/21/2014 07:49 AM, Neil Horman wrote:
> From: "H. Peter Anvin" <hpa@linux.intel.com>
> 
> Neil Horman reported that on x86-64 the upper half of %rbx would get
> clobbered when the code was compiled PIC or PIE, because the
> i386-specific code to preserve %ebx was incorrectly compiled.
> 
> However, the code is really way more complex than it needs to be.  For
> one thing, the CPUID instruction only needs %eax (leaf) and %ecx
> (subleaf) as parameters, and since we are testing for bits, we might
> as well list the bits explicitly.  Furthermore, we can use an array
> rather than doing a switch statement inside a structure.
> 
> Reported-by: Neil Horman <nhorman@tuxdriver.com>
> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
> Tested-by: Neil Horman <nhorman@tuxdriver.com>
> 

Thank you for dealing with this!

On the subject of my other email... are C99 initializers acceptable in
dpdk?  If so, I think making that change, too, would be a good idea.

	-hpa