From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756866AbaJ1LPv (ORCPT ); Tue, 28 Oct 2014 07:15:51 -0400 Received: from terminus.zytor.com ([198.137.202.10]:51398 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752388AbaJ1LPt (ORCPT ); Tue, 28 Oct 2014 07:15:49 -0400 Date: Tue, 28 Oct 2014 04:15:38 -0700 From: tip-bot for Andy Lutomirski Message-ID: Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, hpa@zytor.com, tglx@linutronix.de, luto@amacapital.net Reply-To: luto@amacapital.net, tglx@linutronix.de, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@kernel.org In-Reply-To: <179f490d659307873eefd09206bebd417e2ab5ad.1411494540.git.luto@amacapital.net> References: <179f490d659307873eefd09206bebd417e2ab5ad.1411494540.git.luto@amacapital.net> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/vdso] x86/vdso: Make the PER_CPU segment 32 bits Git-Commit-ID: 287e013108a104e459e675432cf20087feab2b67 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: 287e013108a104e459e675432cf20087feab2b67 Gitweb: http://git.kernel.org/tip/287e013108a104e459e675432cf20087feab2b67 Author: Andy Lutomirski AuthorDate: Tue, 23 Sep 2014 10:50:55 -0700 Committer: Ingo Molnar CommitDate: Tue, 28 Oct 2014 11:22:12 +0100 x86/vdso: Make the PER_CPU segment 32 bits IMO users ought not to be able to use 16-bit segments without using modify_ldt. Fortunately, it's impossible to break espfix64 by loading the PER_CPU segment into SS because it's PER_CPU is marked read-only and SS cannot contain an RO segment, but marking PER_CPU as 32-bit is less fragile. Signed-off-by: Andy Lutomirski Link: http://lkml.kernel.org/r/179f490d659307873eefd09206bebd417e2ab5ad.1411494540.git.luto@amacapital.net Signed-off-by: Ingo Molnar --- arch/x86/vdso/vma.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c index 0c799746..32ca60c 100644 --- a/arch/x86/vdso/vma.c +++ b/arch/x86/vdso/vma.c @@ -268,6 +268,7 @@ static void vsyscall_set_cpu(int cpu) .dpl = 3, /* Visible to user code */ .s = 1, /* Not a system segment */ .p = 1, /* Present */ + .d = 1, /* 32-bit */ }; write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_PER_CPU, &d, DESCTYPE_S);