linux-kernel - [085/262] apic, i386/bigsmp: Fix false warnings regarding logical APIC ID mismatches

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Message-Id: <20111109212709.058337803@clark.kroah.org>
Date:	Wed, 09 Nov 2011 13:26:47 -0800
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	torvalds@...ux-foundation.org, akpm@...ux-foundation.org,
	alan@...rguk.ukuu.org.uk, Jan Beulich <jbeulich@...e.com>,
	Tejun Heo <tj@...nel.org>, Ingo Molnar <mingo@...e.hu>
Subject: [085/262] apic, i386/bigsmp: Fix false warnings regarding logical APIC ID mismatches

3.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jan Beulich <JBeulich@...e.com>

commit 838312be46f3abfbdc175f81c3e54a857994476d upstream.

These warnings (generally one per CPU) are a result of
initializing x86_cpu_to_logical_apicid while apic_default is
still in use, but the check in setup_local_APIC() being done
when apic_bigsmp was already used as an override in
default_setup_apic_routing():

 Overriding APIC driver with bigsmp
 Enabling APIC mode:  Physflat.  Using 5 I/O APICs
 ------------[ cut here ]------------
 WARNING: at .../arch/x86/kernel/apic/apic.c:1239
 ...
 CPU 1 irqstacks, hard=f1c9a000 soft=f1c9c000
 Booting Node   0, Processors  #1
 smpboot cpu 1: start_ip = 9e000
 Initializing CPU#1
 ------------[ cut here ]------------
 WARNING: at .../arch/x86/kernel/apic/apic.c:1239
 setup_local_APIC+0x137/0x46b() Hardware name: ...
 CPU1 logical APIC ID: 2 != 8
 ...

Fix this (for the time being, i.e. until
x86_32_early_logical_apicid() will get removed again, as Tejun
says ought to be possible) by overriding the previously stored
values at the point where the APIC driver gets overridden.

v2: Move this and the pre-existing override logic into
    arch/x86/kernel/apic/bigsmp_32.c.

Signed-off-by: Jan Beulich <jbeulich@...e.com>
Acked-by: Tejun Heo <tj@...nel.org>
Link: http://lkml.kernel.org/r/4E835D16020000780005844C@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@...e.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 arch/x86/include/asm/apic.h      |    2 +-
 arch/x86/kernel/apic/bigsmp_32.c |   20 ++++++++++++++++----
 arch/x86/kernel/apic/probe_32.c  |   10 ++--------
 3 files changed, 19 insertions(+), 13 deletions(-)

--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -495,7 +495,7 @@ static inline void default_wait_for_init
 	return;
 }
 
-extern struct apic *generic_bigsmp_probe(void);
+extern void generic_bigsmp_probe(void);
 
 
 #ifdef CONFIG_X86_LOCAL_APIC
--- a/arch/x86/kernel/apic/bigsmp_32.c
+++ b/arch/x86/kernel/apic/bigsmp_32.c
@@ -255,12 +255,24 @@ static struct apic apic_bigsmp = {
 	.x86_32_early_logical_apicid	= bigsmp_early_logical_apicid,
 };
 
-struct apic * __init generic_bigsmp_probe(void)
+void __init generic_bigsmp_probe(void)
 {
-	if (probe_bigsmp())
-		return &apic_bigsmp;
+	unsigned int cpu;
 
-	return NULL;
+	if (!probe_bigsmp())
+		return;
+
+	apic = &apic_bigsmp;
+
+	for_each_possible_cpu(cpu) {
+		if (early_per_cpu(x86_cpu_to_logical_apicid,
+				  cpu) == BAD_APICID)
+			continue;
+		early_per_cpu(x86_cpu_to_logical_apicid, cpu) =
+			bigsmp_early_logical_apicid(cpu);
+	}
+
+	pr_info("Overriding APIC driver with %s\n", apic_bigsmp.name);
 }
 
 apic_driver(apic_bigsmp);
--- a/arch/x86/kernel/apic/probe_32.c
+++ b/arch/x86/kernel/apic/probe_32.c
@@ -200,14 +200,8 @@ void __init default_setup_apic_routing(v
 	 * - we find more than 8 CPUs in acpi LAPIC listing with xAPIC support
 	 */
 
-	if (!cmdline_apic && apic == &apic_default) {
-		struct apic *bigsmp = generic_bigsmp_probe();
-		if (bigsmp) {
-			apic = bigsmp;
-			printk(KERN_INFO "Overriding APIC driver with %s\n",
-			       apic->name);
-		}
-	}
+	if (!cmdline_apic && apic == &apic_default)
+		generic_bigsmp_probe();
 #endif
 
 	if (apic->setup_apic_routing)


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