linux-kernel - Re: [PATCH 4/8] x86, mce: rename bootparam parser

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Message-ID: <4DFED129.20307@jp.fujitsu.com>
Date:	Mon, 20 Jun 2011 13:48:41 +0900
From:	Hidetoshi Seto <seto.hidetoshi@...fujitsu.com>
To:	Borislav Petkov <bp@...en8.de>, "Luck, Tony" <tony.luck@...el.com>,
	Borislav Petkov <bp@...64.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"x86@...nel.org" <x86@...nel.org>, Ingo Molnar <mingo@...e.hu>,
	Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH 4/8] x86, mce: rename bootparam parser

(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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