From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Monjalon Subject: Re: [RFC UNTESTED PATCH] eal_common_cpuflags: Fix %rbx corruption, and simplify the code Date: Thu, 20 Mar 2014 18:02:52 +0100 Message-ID: <2288041.gdk3FRcxLX@xps13> References: <1395330830-1310-1-git-send-email-hpa@linux.intel.com> <20140320163921.GC7721@hmsreliant.think-freely.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: dev-VfR2kkLFssw@public.gmane.org, "H. Peter Anvin" To: Neil Horman , "H. Peter Anvin" Return-path: In-Reply-To: <20140320163921.GC7721-B26myB8xz7F8NnZeBjwnZQMhkBWG/bsMQH7oEaQurus@public.gmane.org> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces-VfR2kkLFssw@public.gmane.org Sender: "dev" Hi, 20/03/2014 12:39, Neil Horman : > On Thu, Mar 20, 2014 at 08:53:50AM -0700, H. Peter Anvin wrote: > > 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 > > Signed-off-by: H. Peter Anvin > > Acked-by: Neil Horman This is a RFC UNTESTED patch. So should I understand with this acknowledgement that you have tested it? As a shared library? in 32-bit mode? -- Thomas