From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: [PATCH 0/3] Remove interrupt stack table usage from x86_64 kernel Date: Sun, 28 Dec 2008 20:08:40 +0100 Message-ID: <20081228190840.GD496@one.firstfloor.org> References: <1230238726-17506-1-git-send-email-avi@redhat.com> <87vdt5vfxc.fsf@basil.nowhere.org> <4956A0B1.1060908@redhat.com> <20081227224029.GB496@one.firstfloor.org> <49573FE7.9090802@redhat.com> <20081228131605.GC496@one.firstfloor.org> <49578896.8030703@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andi Kleen , x86@kernel.org, Ingo Molnar , linux-kernel , KVM list To: Avi Kivity Return-path: Received: from one.firstfloor.org ([213.235.205.2]:45084 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753347AbYL1Szd (ORCPT ); Sun, 28 Dec 2008 13:55:33 -0500 Content-Disposition: inline In-Reply-To: <49578896.8030703@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Sun, Dec 28, 2008 at 04:09:26PM +0200, Avi Kivity wrote: > I don't see how syscall could work on i386, and indeed: i386 has task gates which support unconditional stack switching. But there are no 64bit task gates, just ISTs. BTW I think there are more similar problems in your patch too. > > >vdso32.so-$(VDSO32-y) += int80 > >vdso32.so-$(CONFIG_COMPAT) += syscall > >vdso32.so-$(VDSO32-y) += sysenter > > It's disabled. Is that the reason? No. All interesting 32bit CPUs have SYSENTER; the only one who has SYSCALL but no SYSENTER is the K6, but it has a weird early variant of SYSCALL with more problems which was never worth supporting. -Andi -- ak@linux.intel.com