From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1Sd0Ly-0004ap-Jh for kexec@lists.infradead.org; Fri, 08 Jun 2012 14:39:56 +0000 Date: Fri, 8 Jun 2012 10:39:49 -0400 From: Vivek Goyal Subject: Re: [PATCH] ppc/ppc64: Compile purgatory code with gcc option -msoft-float Message-ID: <20120608143949.GC29471@redhat.com> References: <20120608134315.GA29791@redhat.com> <20120608134801.GZ24904@tucnak.redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20120608134801.GZ24904@tucnak.redhat.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: kexec-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Jakub Jelinek Cc: Lingzhu Xiang , kexec@lists.infradead.org, Simon Horman , "Suzuki K. Poulose" , "Eric W. Biederman" , Jeremy Kerr On Fri, Jun 08, 2012 at 03:48:01PM +0200, Jakub Jelinek wrote: > On Fri, Jun 08, 2012 at 09:43:15AM -0400, Vivek Goyal wrote: > > Recently we faced an issue on power7 machine where kernel hanged in purgatory. > > Some investigation revealed that gcc is generating hardware FPU instructions. > > I have been told we can't use it at this point of time and as kernel is > > compiled with -msoft-float for ppc/ppc64, so should be purgatory (as it runs > > inside kernel context). > > > > Thanks to Jakub Jelinek and Lingzhu Xiang for debugging and coming up with > > a fix for this issue. > > IMNSHO as a follow-up all other architectures should be changed to > compile kernel code with the right kernel CFLAGS (e.g. -mcmodel=kernel > -mno-sse -mno-mmx should be used probably on x86_64, etc.). Sure. These changes can be done in separate patches. BTW, What does -mcmodel do and why should we use -mcmodel? purgatory, is a separate binary which we reloate at turn time based on physical memory location. IOW, why should we make any assumptions about running location of purgatory and pass -mcmodel flag. Eric, would have have any objections to making use of above gcc flags for purgatory? > > Furthermore, is there still a reason to compile sha256.c with -O0? If > there was a compiler bug? on ia64 6 years ago, with which gcc version > it was, has the problem been reported and resolved? Compiling code like > hash computation unconditionally everywhere at -O0 must IMHO pessimize > things unnecessarily. git blame points to following commit for forcing -O0 on sha256. CCing Jermey, if we can give some details why -O2 was a problem on IA6 and if problem is still there if he has objections if we swtich back to -O2. commit adf85cbc1756e56c1f52f56235a3c08b3c5b8e05 Author: Jeremy Kerr Date: Thu Dec 13 16:18:53 2007 +0900 Build system simplification/standardisation Thanks Vivek _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec