Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753249AbbBYAcR (ORCPT ); Tue, 24 Feb 2015 19:32:17 -0500 Received: from mail-qa0-f45.google.com ([209.85.216.45]:36098 "EHLO mail-qa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752735AbbBYAcP (ORCPT ); Tue, 24 Feb 2015 19:32:15 -0500 MIME-Version: 1.0 In-Reply-To: References: <1424822419-10267-1-git-send-email-dvlasenk@redhat.com> <1424822419-10267-2-git-send-email-dvlasenk@redhat.com> From: Denys Vlasenko Date: Wed, 25 Feb 2015 01:31:54 +0100 Message-ID: Subject: Re: [PATCH 2/7] x86: entry.S: simplify optimistic SYSRET To: Andy Lutomirski Cc: Denys Vlasenko , Linus Torvalds , Steven Rostedt , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Oleg Nesterov , Frederic Weisbecker , Alexei Starovoitov , Will Drewry , Kees Cook , X86 ML , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 831 Lines: 22 On Wed, Feb 25, 2015 at 1:04 AM, Andy Lutomirski wrote: >> --- a/arch/x86/kernel/entry_64.S >> +++ b/arch/x86/kernel/entry_64.S >> @@ -756,9 +756,8 @@ retint_swapgs: /* return to user-space */ >> */ >> irq_return_via_sysret: >> CFI_REMEMBER_STATE >> - RESTORE_C_REGS >> - REMOVE_PT_GPREGS_FROM_STACK 8 >> - movq (RSP-RIP)(%rsp),%rsp >> + RESTORE_C_REGS_EXCEPT_R11 >> + movq RSP(%rsp),%rsp > > I think this needs a comment. I assume you mean "a comment why r11 doesn't need restoring". I sent patch v2. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/