From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from bh-25.webhostbox.net ([208.91.199.152]:49263 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751063AbbAKQNY (ORCPT ); Sun, 11 Jan 2015 11:13:24 -0500 Received: from mailnull by bh-25.webhostbox.net with sa-checked (Exim 4.82) (envelope-from ) id 1YAL8m-0042NG-A5 for linux-watchdog@vger.kernel.org; Sun, 11 Jan 2015 16:13:24 +0000 Message-ID: <54B2A120.9040504@roeck-us.net> Date: Sun, 11 Jan 2015 08:13:20 -0800 From: Guenter Roeck MIME-Version: 1.0 To: Lars-Peter Clausen , =?windows-1252?Q?M=E5ns_Rullg?= =?windows-1252?Q?=E5rd?= CC: Ralf Baechle , Wim Van Sebroeck , Paul Burton , Paul Cercueil , Maarten ter Huurne , linux-mips@linux-mips.org, linux-watchdog@vger.kernel.org Subject: Re: [PATCH 1/3] MIPS: Use do_kernel_restart() as the default restart handler References: <1420914550-18335-1-git-send-email-lars@metafoo.de> <54B1CF9B.3060606@roeck-us.net> <54B26BB4.50707@metafoo.de> In-Reply-To: <54B26BB4.50707@metafoo.de> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-watchdog-owner@vger.kernel.org List-Id: linux-watchdog@vger.kernel.org On 01/11/2015 04:25 AM, Lars-Peter Clausen wrote: > On 01/11/2015 01:15 PM, Måns Rullgård wrote: >> Guenter Roeck writes: >> >>> On 01/10/2015 12:08 PM, Måns Rullgård wrote: >>>> Lars-Peter Clausen writes: >>>> >>>>> Use the recently introduced do_kernel_restart() function as the default restart >>>>> handler if the platform did not explicitly provide a restart handler. This >>>>> allows use restart handler that have been registered by device drivers to >>>>> restart the machine. >>>>> >>>>> Signed-off-by: Lars-Peter Clausen >>>>> --- >>>>> arch/mips/kernel/reset.c | 2 +- >>>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>>> >>>>> diff --git a/arch/mips/kernel/reset.c b/arch/mips/kernel/reset.c >>>>> index 07fc524..36cd80c 100644 >>>>> --- a/arch/mips/kernel/reset.c >>>>> +++ b/arch/mips/kernel/reset.c >>>>> @@ -19,7 +19,7 @@ >>>>> * So handle all using function pointers to machine specific >>>>> * functions. >>>>> */ >>>>> -void (*_machine_restart)(char *command); >>>>> +void (*_machine_restart)(char *command) = do_kernel_restart; >>>>> void (*_machine_halt)(void); >>>>> void (*pm_power_off)(void); >>>> >>>> There is already a similar patch posted by Kevin Cernekee: >>>> http://www.linux-mips.org/archives/linux-mips/2014-12/msg00410.html >>>> >>> Personally I prefer the earlier patch, though I guess that is personal >>> preference. >> >> They both achieve the same thing, though Kevin's is more in line with >> what ARM does. Missing from both is a fallback while(1) loop in case no >> restart handlers are registered. With the restart moved to the watchdog >> driver, there's a possibility that this might happen. >> > > In my opinion if such a fallback is needed it should be put into the kernel core reboot implementation and not into individual restart handler implementations. > Agreed. > My first version of this patch was do_kernel_restart() followed by a machine_halt() (so it goes to sleep instead of busy looping) as a fallback. But I couldn't find a good reason why that should be done at the individual restart handler level, so I dropped it. > That should probably be added to do_kernel_restart(). Guenter