linux-kernel - Re: [RFC -tip] x86,apic - set cpu_has

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Message-ID: <20090712063445.GC4782@lenovo>
Date:	Sun, 12 Jul 2009 10:34:45 +0400
From:	Cyrill Gorcunov <gorcunov@...il.com>
To:	"Maciej W. Rozycki" <macro@...ux-mips.org>
Cc:	Ingo Molnar <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Yinghai Lu <yinghai@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [RFC -tip] x86,apic - set cpu_has_apic for discrete apic

[Maciej W. Rozycki - Sun, Jul 12, 2009 at 07:31:44AM +0100]
| On Sun, 12 Jul 2009, Cyrill Gorcunov wrote:
| 
| >   Well, I've been using code reading. No real hardware test.
| > I just don't have such a hardware.
| 
|  Then simulate it!  Proofreading is not enough -- the APIC code is too 
| twisted.  Be imaginative -- for example you can clear the APIC bit at the 
| time CPUID flags are saved for later use with cpu_has_apic() and see if 
| the code behaves as expected.  Sprinkle printk()s here and there to see if 
| variables are set correctly, whether the right code paths are taken, etc.  
| Tedious?  Well, who said kernel debugging was going to be a piece of cake?
| 
|  Most of the APIC support code I have written has been run-time tested 
| like this -- one change at a time.  Do you think I have an infinite number 
| of SMP configurations too?  All the clean-ups I worked on last year were 
| tested with one laptop.  I didn't even have a serial port for console 
| dumps back then.
| 
|  NAK from me until you've tested it, sorry.

Started to... hope to publish results today!
Thanks Maciej!

| 
|   Maciej
| 
	-- Cyrill
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