linux-kernel - Re: [PATCH] x86: do_boot_cpu - check for ESR apic register presence before touching

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Message-ID: <20080915163016.GC23798@lenovo>
Date:	Mon, 15 Sep 2008 20:30:16 +0400
From:	Cyrill Gorcunov <gorcunov@...il.com>
To:	Yinghai Lu <yhlu.kernel@...il.com>
Cc:	Ingo Molnar <mingo@...e.hu>,
	"Maciej W. Rozycki" <macro@...ux-mips.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86: do_boot_cpu - check for ESR apic register
	presence before touching

[Yinghai Lu - Mon, Sep 15, 2008 at 09:25:14AM -0700]
| On Mon, Sep 15, 2008 at 9:22 AM, Cyrill Gorcunov <gorcunov@...il.com> wrote:
| > [Yinghai Lu - Mon, Sep 15, 2008 at 09:12:37AM -0700]
| > | On Mon, Sep 15, 2008 at 8:05 AM, Cyrill Gorcunov <gorcunov@...il.com> wrote:
| > | > We should check first if there is ESR register before read/write it.
| > | >
| > | > Signed-off-by: Cyrill Gorcunov <gorcunov@...il.com>
| > | > ---
| > | >
| > | > Please review and test if possible. Thanks.
| > | >
| > | > Index: linux-2.6.git/arch/x86/kernel/smpboot.c
| > | > ===================================================================
| > | > --- linux-2.6.git.orig/arch/x86/kernel/smpboot.c        2008-09-14 21:49:36.000000000 +0400
| > | > +++ linux-2.6.git/arch/x86/kernel/smpboot.c     2008-09-15 18:30:37.000000000 +0400
| > | > @@ -893,8 +893,10 @@ do_rest:
| > | >                /*
| > | >                 * Be paranoid about clearing APIC errors.
| > | >                */
| > | > -               apic_write(APIC_ESR, 0);
| > | > -               apic_read(APIC_ESR);
| > | > +               if (APIC_INTEGRATED(apic_version[phys_apicid])) {
| > | > +                       apic_write(APIC_ESR, 0);
| > | > +                       apic_read(APIC_ESR);
| > | > +               }
| > | >        }
| > | >
| > | >        /*
| > | >
| > |
| > | maybe unrelated. Do we need to keep apic_version array?
| > |
| > | YH
| > |
| >
| > as I see ACPI/MP parsing code use it - actually I think we could
| > bring another variable - but don't think it worth it. Anyway
| > we have to get APIC info from these tables and save it somwhere
| > maybe in this array or maybe in another variable. Or you mean
| > anything else that I missed?
| 
| one apic_version or boot_cpu_apic_version could be enough.
| 
| YH
|

Yinghai I didn't check it - if you find it convenient -
I'll not object against... Maciej?

		- Cyrill -
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