From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753008AbdFMKOf (ORCPT ); Tue, 13 Jun 2017 06:14:35 -0400 Received: from terminus.zytor.com ([65.50.211.136]:47247 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751908AbdFMKOd (ORCPT ); Tue, 13 Jun 2017 06:14:33 -0400 Date: Tue, 13 Jun 2017 03:06:48 -0700 From: "tip-bot for Kirill A. Shutemov" Message-ID: Cc: akpm@linux-foundation.org, dvlasenk@redhat.com, bp@alien8.de, tglx@linutronix.de, luto@amacapital.net, jpoimboe@redhat.com, torvalds@linux-foundation.org, brgerst@gmail.com, luto@kernel.org, hpa@zytor.com, dave.hansen@intel.com, linux-kernel@vger.kernel.org, peterz@infradead.org, matt@codeblueprint.co.uk, kirill.shutemov@linux.intel.com, mingo@kernel.org Reply-To: dvlasenk@redhat.com, tglx@linutronix.de, bp@alien8.de, akpm@linux-foundation.org, torvalds@linux-foundation.org, brgerst@gmail.com, jpoimboe@redhat.com, luto@amacapital.net, dave.hansen@intel.com, linux-kernel@vger.kernel.org, hpa@zytor.com, luto@kernel.org, mingo@kernel.org, kirill.shutemov@linux.intel.com, matt@codeblueprint.co.uk, peterz@infradead.org In-Reply-To: <20170606113133.22974-6-kirill.shutemov@linux.intel.com> References: <20170606113133.22974-6-kirill.shutemov@linux.intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/mm] x86/boot/efi: Define __KERNEL32_CS GDT on 64-bit configurations Git-Commit-ID: 919a02d1280a3845bac70e6b7891ca070f21a60a X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 919a02d1280a3845bac70e6b7891ca070f21a60a Gitweb: http://git.kernel.org/tip/919a02d1280a3845bac70e6b7891ca070f21a60a Author: Kirill A. Shutemov AuthorDate: Tue, 6 Jun 2017 14:31:24 +0300 Committer: Ingo Molnar CommitDate: Tue, 13 Jun 2017 08:56:53 +0200 x86/boot/efi: Define __KERNEL32_CS GDT on 64-bit configurations We would need to switch temporarily to compatibility mode during booting with 5-level paging enabled. It would require 32-bit code segment descriptor. Signed-off-by: Kirill A. Shutemov Reviewed-by: Matt Fleming Cc: Andrew Morton Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-arch@vger.kernel.org Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20170606113133.22974-6-kirill.shutemov@linux.intel.com Signed-off-by: Ingo Molnar --- arch/x86/boot/compressed/eboot.c | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c index b75c20f..c3e869e 100644 --- a/arch/x86/boot/compressed/eboot.c +++ b/arch/x86/boot/compressed/eboot.c @@ -1046,8 +1046,29 @@ struct boot_params *efi_main(struct efi_config *c, memset((char *)gdt->address, 0x0, gdt->size); desc = (struct desc_struct *)gdt->address; - /* The first GDT is a dummy and the second is unused. */ - desc += 2; + /* The first GDT is a dummy. */ + desc++; + + if (IS_ENABLED(CONFIG_X86_64)) { + /* __KERNEL32_CS */ + desc->limit0 = 0xffff; + desc->base0 = 0x0000; + desc->base1 = 0x0000; + desc->type = SEG_TYPE_CODE | SEG_TYPE_EXEC_READ; + desc->s = DESC_TYPE_CODE_DATA; + desc->dpl = 0; + desc->p = 1; + desc->limit = 0xf; + desc->avl = 0; + desc->l = 0; + desc->d = SEG_OP_SIZE_32BIT; + desc->g = SEG_GRANULARITY_4KB; + desc->base2 = 0x00; + desc++; + } else { + /* Second entry is unused on 32-bit */ + desc++; + } /* __KERNEL_CS */ desc->limit0 = 0xffff;