From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grant Grundler Subject: Re: [parisc-linux] Space registers and how to use them Date: Wed, 5 Oct 2005 22:59:36 -0600 Message-ID: <20051006045936.GA27034@colo.lackof.org> References: <20050925173513.GA22786@colo.lackof.org> <200509251803.j8PI3tLI014517@hiauly1.hia.nrc.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: parisc-linux@parisc-linux.org To: John David Anglin Return-Path: In-Reply-To: <200509251803.j8PI3tLI014517@hiauly1.hia.nrc.ca> 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 On Sun, Sep 25, 2005 at 02:03:55PM -0400, John David Anglin wrote: > > John was just saying it doesn't matter since parisc-linux uses > > the same value in all four (sr4-7) space registers. > > It's possible for user code to mess with sr4. It's not a > privileged register. Certainly. But in the kernel those are KERNEL_SPACE (zero). We save/restore the user space values for sr4-7. We clear sr4-sr7 in linux_gateway_entry (arch/parisc/kernel/syscall.S) for syscalls. We do the same for interrupts in virt_map macro in entry.S. grant _______________________________________________ parisc-linux mailing list parisc-linux@lists.parisc-linux.org http://lists.parisc-linux.org/mailman/listinfo/parisc-linux