From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757543Ab3BKOWp (ORCPT ); Mon, 11 Feb 2013 09:22:45 -0500 Received: from mail.skyhub.de ([78.46.96.112]:45171 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757232Ab3BKOWY (ORCPT ); Mon, 11 Feb 2013 09:22:24 -0500 From: Borislav Petkov To: "H. Peter Anvin" Cc: X86 ML , LKML , Borislav Petkov Subject: [PATCH 1/4] x86, head_32: Remove i386 pieces Date: Mon, 11 Feb 2013 15:22:15 +0100 Message-Id: <1360592538-10643-2-git-send-email-bp@alien8.de> X-Mailer: git-send-email 1.8.1.3.535.ga923c31 In-Reply-To: <1360592538-10643-1-git-send-email-bp@alien8.de> References: <1360592538-10643-1-git-send-email-bp@alien8.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Borislav Petkov Remove code fragments detecting a 386 CPU since we don't support those anymore. Also, do not do alignment checks because they're done only at CPL3. Also, no need to preserve EFLAGS. Signed-off-by: Borislav Petkov --- arch/x86/kernel/head_32.S | 22 +++++----------------- 1 file changed, 5 insertions(+), 17 deletions(-) diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index 0b8c825fc264..f4d919e2cd2b 100644 --- a/arch/x86/kernel/head_32.S +++ b/arch/x86/kernel/head_32.S @@ -405,30 +405,21 @@ default_entry: jz 1f # Did we do this already? call *%eax 1: - -/* check if it is 486 or 386. */ + /* - * XXX - this does a lot of unnecessary setup. Alignment checks don't - * apply at our cpl of 0 and the stack ought to be aligned already, and - * we don't need to preserve eflags. + * Check if it is 486 */ movl $-1,X86_CPUID # -1 for no CPUID initially - movb $3,X86 # at least 386 + movb $4,X86 # at least 486 pushfl # push EFLAGS popl %eax # get EFLAGS movl %eax,%ecx # save original EFLAGS - xorl $0x240000,%eax # flip AC and ID bits in EFLAGS + xorl $0x200000,%eax # flip ID bit in EFLAGS pushl %eax # copy to EFLAGS popfl # set EFLAGS pushfl # get new EFLAGS popl %eax # put it in eax xorl %ecx,%eax # change in flags - pushl %ecx # restore original EFLAGS - popfl - testl $0x40000,%eax # check if AC bit changed - je is386 - - movb $4,X86 # at least 486 testl $0x200000,%eax # check if ID bit changed je is486 @@ -456,10 +447,7 @@ default_entry: movl %edx,X86_CAPABILITY is486: movl $0x50022,%ecx # set AM, WP, NE and MP - jmp 2f - -is386: movl $2,%ecx # set MP -2: movl %cr0,%eax + movl %cr0,%eax andl $0x80000011,%eax # Save PG,PE,ET orl %ecx,%eax movl %eax,%cr0 -- 1.8.1.3.535.ga923c31