From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jes Sorensen Subject: Re: [parisc-linux] [RFC] using 64bit wide registers with 32bit kernel Date: Mon, 15 May 2006 12:56:16 +0200 Message-ID: <44685E50.7040908@sgi.com> References: <7d01f9f00605130841v6185b06dybae82c9f9c77e2b4@mail.gmail.com> <1147539787.6632.7.camel@mulgrave.il.steeleye.com> <7d01f9f00605150255u5846f144u9c95cab3ffd35133@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: James Bottomley , parisc-linux@lists.parisc-linux.org To: Thibaut VARENE Return-Path: In-Reply-To: <7d01f9f00605150255u5846f144u9c95cab3ffd35133@mail.gmail.com> List-Id: parisc-linux developers list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: parisc-linux-bounces@lists.parisc-linux.org Thibaut VARENE wrote: > On 15 May 2006 05:10:15 -0400, Jes Sorensen wrote: >> What about setting an ELF flag or somesuch, set a task flag based on >> this and then only do the extended register file backup for these >> apps? > > If that's possible *and* acceptable, it might be very helpful indeed. I don't know anything about the PARISC ELF specification, but I think it ought to be feasible. Alternatively, if you can trap the instruction so you get a kernel trap the first time the user app tries to do this and then set the flag then. Otherwise there is the problem that someone will do some hand tuned assembly that uses the 64 bit regs and you end up with mocked up state if this goes undetected. Cheers, Jes _______________________________________________ parisc-linux mailing list parisc-linux@lists.parisc-linux.org http://lists.parisc-linux.org/mailman/listinfo/parisc-linux