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SubjectRe: [PATCH] x86: smpboot - check if we have ESR register in wakeup_secondary_cpu
[Ingo Molnar - Mon, Sep 15, 2008 at 09:56:55AM +0200]
|
| * Cyrill Gorcunov <gorcunov@gmail.com> wrote:
|
| > We should check if we have ESR register before writting to it.
| >
| > Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
| > ---
| >
| > Please review!
| > it seems the same nit in do_boot_cpu - checking now.
| >
| > Index: linux-2.6.git/arch/x86/kernel/smpboot.c
| > ===================================================================
| > --- linux-2.6.git.orig/arch/x86/kernel/smpboot.c 2008-09-14 19:43:03.000000000 +0400
| > +++ linux-2.6.git/arch/x86/kernel/smpboot.c 2008-09-14 21:49:36.000000000 +0400
| > @@ -598,10 +598,12 @@ wakeup_secondary_cpu(int logical_apicid,
| > * Give the other CPU some time to accept the IPI.
| > */
| > udelay(200);
| > - maxlvt = lapic_get_maxlvt();
| > - if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
| > - apic_write(APIC_ESR, 0);
| > - accept_status = (apic_read(APIC_ESR) & 0xEF);
| > + if (APIC_INTEGRATED(apic_version[phys_apicid])) {
| > + maxlvt = lapic_get_maxlvt();
| > + if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
| > + apic_write(APIC_ESR, 0);
| > + accept_status = (apic_read(APIC_ESR) & 0xEF);
| > + }
| > pr_debug("NMI sent.\n");
|
| hm, is there any non-integrated lapic that has more than 3 lvts? iirc
| lvts were introduced with the integrated lapic.
|
| Ingo
|

Ingo, here is an updated version of patch - only subject
and patch message updated (not patch body)

- Cyrill -
---
From: Cyrill Gorcunov <gorcunov@gmail.com>
Subject: x86: wakeup_secondary_cpu - check if we have ESR register to read
We shouldn't read ESR register on discrete APIC.
Check it first.

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
---
Index: linux-2.6.git/arch/x86/kernel/smpboot.c
===================================================================
--- linux-2.6.git.orig/arch/x86/kernel/smpboot.c 2008-09-14 19:43:03.000000000 +0400
+++ linux-2.6.git/arch/x86/kernel/smpboot.c 2008-09-14 21:49:36.000000000 +0400
@@ -598,10 +598,12 @@ wakeup_secondary_cpu(int logical_apicid,
* Give the other CPU some time to accept the IPI.
*/
udelay(200);
- maxlvt = lapic_get_maxlvt();
- if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
- apic_write(APIC_ESR, 0);
- accept_status = (apic_read(APIC_ESR) & 0xEF);
+ if (APIC_INTEGRATED(apic_version[phys_apicid])) {
+ maxlvt = lapic_get_maxlvt();
+ if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
+ apic_write(APIC_ESR, 0);
+ accept_status = (apic_read(APIC_ESR) & 0xEF);
+ }
pr_debug("NMI sent.\n");

if (send_status)

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