Message-ID: <4DFED129.20307@jp.fujitsu.com>
Date: Mon, 20 Jun 2011 13:48:41 +0900
From: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
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To: Borislav Petkov <bp@alien8.de>, "Luck, Tony" <tony.luck@intel.com>,
        Borislav Petkov <bp@amd64.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "x86@kernel.org" <x86@kernel.org>, Ingo Molnar <mingo@elte.hu>,
        Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH 4/8] x86, mce: rename bootparam parser
References: <4DFB1242.90404@jp.fujitsu.com> <4DFB13E2.4080909@jp.fujitsu.com> <20110617154143.GC20010@aftab> <987664A83D2D224EAE907B061CE93D5301E8E3054B@orsmsx505.amr.corp.intel.com> <20110618083820.GA27319@liondog.tnic>
In-Reply-To: <20110618083820.GA27319@liondog.tnic>
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(2011/06/18 17:38), Borislav Petkov wrote:
> On Fri, Jun 17, 2011 at 03:25:51PM -0700, Luck, Tony wrote:
>>> and leave this like this. "nomce" is the same as "mce=off" and frankly,
>>> I'd like to remove this redundancy, thus no need to do the code
>>> relocation. In addition, I don't think there are lots of systems running
>>> with "nomce" so I really think we should drop it.
>>>
>>> So Ingo, hpa, what is the proper way to remove early setup params? Maybe
>>> through Documentation/feature-removal-schedule.txt?
>>
>> Though it seems odd to me that anyone would want to turn mce off,
>> the fact that we have two ways to do so would indicate that people
>> do (or at least did) want to do this.
> 
> Yeah, the only usecase I could think of for this is people doing their
> own userspace DRAM ECC evaluation like google. But they'd still need to
> have an #MC handler... or they could parse syslog for the output from
> the default unexpected_machine_check().. hm.
> 
>> It seems like we'd need a long "deprecated" period (till all the
>> major OSVs turn out a new release) to remove this without surprises.
>> If the "nomce" option just disappears, then people using it will
>> not realize that their boot time argument was ignored (until they
>> see a reported error).
> 
> Yeah, we could do a grace period with a warning:
> 
> /*
>  * Old style boot options parsing. Only for compatibility.
>  */
> static int __init mcheck_disable(char *str)
> {
> 	pr_err("\"nomce\" boot param is deprecated. Please use \"mce=off\"\n");
> 
> 	mce_disabled = 1;
> 	return 1;
> }
> __setup("nomce", mcheck_disable);
> 
> and then kill it.

Thank you for giving a new direction!
I'll write a patch to "deprecate nomce" instead of this rename/cleanup.


Thanks,
H.Seto

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