From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.genesi-usa.com (mithrandir.softwarenexus.net [66.98.186.96]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id ED9C1DDE37 for ; Wed, 26 Sep 2007 23:58:52 +1000 (EST) Message-ID: <46FA65FC.4000208@genesi-usa.com> Date: Wed, 26 Sep 2007 15:00:28 +0100 From: Matt Sealey MIME-Version: 1.0 To: Segher Boessenkool Subject: Re: [PATCH] add Altivec/VMX state to coredumps References: <46F88896.50706@au1.ibm.com> <46F94CBA.2060901@genesi-usa.com> <1190758712.23457.0.camel@localhost.localdomain> <46FA3CDD.2070409@genesi-usa.com> <997c015e13649d06e246d3d2c1369100@kernel.crashing.org> In-Reply-To: <997c015e13649d06e246d3d2c1369100@kernel.crashing.org> Content-Type: text/plain; charset=UTF-8; format=flowed Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Segher Boessenkool wrote: >>>> Why not put the PVR in core dumps that'd make it all easier.. >>> >>> PVR wouldn't be very useful... What if you have altivec disabled ? Also >>> that would mean your gdb has to know about all new processors... >> >> Is that such a big deal? :D >> >> Hypothetically it would be impossible to determine if you were running >> on a G5 with the FPU and AltiVec turned off or an e500 core with SPE, >> given the data saved. > > And that is exactly as should be: a core dump represents the execution > state of a user program, it has nothing to do with the machine it was > generated on; it even is possible to restart a core dump generated on > e.g. an e500 on a 970, as long as it doesn't use facilities (e.g., SPE) > that the latter processor / execution environment doesn't provide. A hypothetical question for you then.. What happens if you get a core dump for a G4 app which dynamically detects AltiVec presence (from PVR or /proc) then crashes before AltiVec is enabled in the kernel for that task (i.e. before any vector exception) and you run it on your G3 and it magically carries on (maybe a race condition or so) and causes a vector exception later? Isn't that kind of useless? Wouldn't it? -- Matt Sealey Genesi, Manager, Developer Relations