From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751345AbdJCTlR (ORCPT ); Tue, 3 Oct 2017 15:41:17 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:54708 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750961AbdJCTlQ (ORCPT ); Tue, 3 Oct 2017 15:41:16 -0400 Date: Tue, 3 Oct 2017 21:41:13 +0200 (CEST) From: Thomas Gleixner To: Denys Vlasenko cc: Andy Lutomirski , Andy Lutomirski , x86@kernel.org, LKML , Ingo Molnar Subject: Re: Is GET_CR0_INTO_EAX macro unused? In-Reply-To: <9138e8d1-9e31-5ac7-a5cd-727967a847ef@redhat.com> Message-ID: References: <9138e8d1-9e31-5ac7-a5cd-727967a847ef@redhat.com> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2 Oct 2017, Denys Vlasenko wrote: > Hi Andy, > > From by git archaeology, looks like last use of GET_CR0_INTO_EAX > was removed long ago, in 2008 (see commit below). > > Right now, I only grep it here in a comment in entry_32.S: > /* > * We use macros for low-level operations which need to be overridden > * for paravirtualization. The following will never clobber any registers: > * INTERRUPT_RETURN (aka. "iret") > * GET_CR0_INTO_EAX (aka. "movl %cr0, %eax") > > To support GET_CR0_INTO_EAX, paravirt has PV_CPU_read_cr0 a.k.a. > struct pv_cpu_ops::read_cr0 and a bunch of code to support it > for each hypervisor. > > Can we delete it? > Or am I missing a non-obvious place where this macro is still in use? That thing was simply forgotten and bitrots happily since 2008. Thanks, tglx