From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758467AbcK3UfH (ORCPT ); Wed, 30 Nov 2016 15:35:07 -0500 Received: from mail.kernel.org ([198.145.29.136]:59990 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756888AbcK3Ue7 (ORCPT ); Wed, 30 Nov 2016 15:34:59 -0500 From: Andy Lutomirski To: x86@kernel.org Cc: One Thousand Gnomes , Borislav Petkov , "linux-kernel@vger.kernel.org" , Brian Gerst , Matthew Whitehead , Henrique de Moraes Holschuh , Andy Lutomirski Subject: [PATCH 0/4] CPUID-less CPU fixes and improvements Date: Wed, 30 Nov 2016 12:34:51 -0800 Message-Id: X-Mailer: git-send-email 2.9.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org *** PATCHES 1 and 2 MAY BE 4.9 MATERIAL *** Alan Cox pointed out that the 486 isn't the only supported CPU that doesn't have CPUID. Let's clean up the mess. Patch 1 is intended to be an easy fix: it makes sync_core() work without CPUID on all 32-bit kernels. It should be quite safe. This will have a negligible performance cost during boot on kernels built for newer CPUs. With this in place, patch 2 reverts the buggy 486 check I added. Patches 3 and 4 are meant to improve the situation. Patch 3 cleans up the Intel microcode loader and patch 4 (which depends on patch 3) stops using CPUID in sync_core() altogether. Andy Lutomirski (4): x86/asm/32: Make sync_core() handle missing CPUID on all 32-bit kernels Revert "x86/boot: Fail the boot if !M486 and CPUID is missing" x86/microcode/intel: Replace sync_core() with cpuid_eax(1) x86/asm: Change sync_core() to use MOV to CR2 to serialize arch/x86/boot/cpu.c | 6 ------ arch/x86/include/asm/processor.h | 31 ++++++++----------------------- arch/x86/kernel/cpu/microcode/intel.c | 6 +++--- 3 files changed, 11 insertions(+), 32 deletions(-) -- 2.9.3