Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759483AbcLBAgr (ORCPT ); Thu, 1 Dec 2016 19:36:47 -0500 Received: from mail.kernel.org ([198.145.29.136]:45478 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759340AbcLBAfR (ORCPT ); Thu, 1 Dec 2016 19:35:17 -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 , Peter Zijlstra , Andy Lutomirski , Denys Vlasenko , "H . Peter Anvin" , Josh Poimboeuf , Linus Torvalds , Thomas Gleixner Subject: [PATCH v2 2/6] Revert "x86/boot: Fail the boot if !M486 and CPUID is missing" Date: Thu, 1 Dec 2016 16:34:58 -0800 Message-Id: <82acde18a108b8e353180dd6febcc2876df33f24.1480638597.git.luto@kernel.org> X-Mailer: git-send-email 2.9.3 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1561 Lines: 45 This reverts commit ed68d7e9b9cfb64f3045ffbcb108df03c09a0f98. The patch wasn't quite correct -- there are non-Intel (and hence non-486) CPUs that we support that don't have CPUID. Since we no longer require CPUID for sync_core(), just revert the patch. I think the relevant CPUs are Geode and Elan, but I'm not sure. In principle, we should try to do better at identifying CPUID-less CPUs in early boot, but that's more complicated. Reported-by: One Thousand Gnomes Cc: Matthew Whitehead Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Andy Lutomirski --- arch/x86/boot/cpu.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/arch/x86/boot/cpu.c b/arch/x86/boot/cpu.c index 4224ede43b4e..26240dde081e 100644 --- a/arch/x86/boot/cpu.c +++ b/arch/x86/boot/cpu.c @@ -87,12 +87,6 @@ int validate_cpu(void) return -1; } - if (CONFIG_X86_MINIMUM_CPU_FAMILY <= 4 && !IS_ENABLED(CONFIG_M486) && - !has_eflag(X86_EFLAGS_ID)) { - printf("This kernel requires a CPU with the CPUID instruction. Build with CONFIG_M486=y to run on this CPU.\n"); - return -1; - } - if (err_flags) { puts("This kernel requires the following features " "not present on the CPU:\n"); -- 2.9.3