From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754670AbaJXTbt (ORCPT ); Fri, 24 Oct 2014 15:31:49 -0400 Received: from mail-lb0-f178.google.com ([209.85.217.178]:54136 "EHLO mail-lb0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754212AbaJXTbs (ORCPT ); Fri, 24 Oct 2014 15:31:48 -0400 Date: Fri, 24 Oct 2014 21:28:45 +0200 From: Johan Hovold To: Felipe Balbi Cc: Johan Hovold , Russell King , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] ARM: remove redundant irq disable at halt and restart Message-ID: <20141024192845.GC19377@localhost> References: <1414177592-14547-1-git-send-email-johan@kernel.org> <20141024191627.GA11455@saruman> <20141024192111.GC11455@saruman> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141024192111.GC11455@saruman> User-Agent: Mutt/1.5.22 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 24, 2014 at 02:21:11PM -0500, Felipe Balbi wrote: > On Fri, Oct 24, 2014 at 02:16:27PM -0500, Felipe Balbi wrote: > > On Fri, Oct 24, 2014 at 09:06:32PM +0200, Johan Hovold wrote: > > > Remove redundant local_irq_disable() at machine halt and restart. > > > > > > Since commit 44424c34049f ("ARM: 7803/1: Fix deadlock scenario with > > > smp_send_stop()") interrupts are disabled before stopping secondary > > > CPUs. > > > > Assuming this is correct, you should have: > > > > Fixes: 44424c3 (ARM: 7803/1: Fix deadlock scenario with smp_send_stop()) > > Cc: # v3.12+ It's not a bug. Just a redundant disabling of already disabled interrupts, something which could possibly lead someone to believe that interrupts could be re-enabled by the power-off handler. And if that was the case, wouldn't that introduce the bug that 44424c34049f ("ARM: 7803/1: Fix deadlock scenario with smp_send_stop()") was trying to fix? > > > Signed-off-by: Johan Hovold > > > --- > > > arch/arm/kernel/process.c | 2 -- > > > 1 file changed, 2 deletions(-) > > > > > > diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c > > > index a35f6ebbd2c2..5663ab57cf07 100644 > > > --- a/arch/arm/kernel/process.c > > > +++ b/arch/arm/kernel/process.c > > > @@ -195,7 +195,6 @@ void machine_halt(void) > > > local_irq_disable(); > > > smp_send_stop(); > > > > > > - local_irq_disable(); > > > while (1); > > > } > > > > > > @@ -237,7 +236,6 @@ void machine_restart(char *cmd) > > > > > > /* Whoops - the platform was unable to reboot. Tell the user! */ > > > printk("Reboot failed -- System halted\n"); > > > - local_irq_disable(); > > > > ... but wouldn't this reintroduce the the buck which that commit fixed ? > > s/buck/bug :-) my fingers have a mind of their own, aparently. :) No, the interrupts would still be disabled. Thanks, Johan