From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756411Ab1GENAZ (ORCPT ); Tue, 5 Jul 2011 09:00:25 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:37131 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756367Ab1GENAX (ORCPT ); Tue, 5 Jul 2011 09:00:23 -0400 X-IronPort-AV: E=Sophos;i="4.65,479,1304308800"; d="scan'208";a="153527743" From: Ian Campbell To: Cyrill Gorcunov CC: linux-kernel@vger.kernel.org, Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , Brian Gerst , Jan Beulich , Peter Zijlstra , Frederic Weisbecker , Ian Campbell , x86@kernel.org Subject: [PATCH 2/3] x86: make 64 bit ret_from_fork a little more similar to 32 bit Date: Tue, 5 Jul 2011 14:00:13 +0100 Message-ID: <1309870814-14181-2-git-send-email-ian.campbell@citrix.com> X-Mailer: git-send-email 1.7.2.5 In-Reply-To: <20110705111525.GR17941@sun> References: <20110705111525.GR17941@sun> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The 64 bit version resets EFLAGS before calling schedule_tail() and therefore leaves EFLAGS.IF clear. 32 bit resets EFLAGS after calling schedule_tail() and therefore leaves EFLAGS.IF set. I don't think there is any practical difference between the two approaches since interrupts are actually reenabled within schedule_tail (schedule_tail->finish_task_switch->finish_lock_switch->raw_spin_unlock_irq->...->local_irq_enable) so arbitrarily pick the 32 bit version and make 64 bit look like that. Signed-off-by: Ian Campbell Cc: x86@kernel.org --- arch/x86/kernel/entry_64.S | 7 ++++--- 1 files changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index b50d142..9c28bd5 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -394,13 +394,14 @@ END(save_paranoid) ENTRY(ret_from_fork) DEFAULT_FRAME - LOCK ; btr $TIF_FORK,TI_flags(%r8) - pushq_cfi $0x0002 - popfq_cfi # reset kernel eflags + LOCK ; btr $TIF_FORK,TI_flags(%r8) call schedule_tail # rdi: 'prev' task parameter + pushq_cfi $0x0202 + popfq_cfi # reset kernel eflags + GET_THREAD_INFO(%rcx) RESTORE_REST -- 1.7.2.5