From 3777a95903953c55f2309a89679b73c19ae5535b Mon Sep 17 00:00:00 2001
From: Andi Kleen <ak@suse.de>
Date: Fri, 3 Feb 2006 21:51:53 +0100
Subject: [PATCH] [PATCH] i386/x86-64: Don't ack the APIC for bad interrupts
 when the APIC is not enabled

It's bad juju to touch the APIC when it hasn't been enabled.
I also moved ack_bad_irq for x86-64 out of line following i386.

Signed-off-by: Andi Kleen <ak@suse.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
 arch/i386/kernel/apic.c      |  5 ++++-
 arch/x86_64/kernel/apic.c    | 20 ++++++++++++++++++++
 include/asm-x86_64/hardirq.h | 21 ++-------------------
 3 files changed, 26 insertions(+), 20 deletions(-)

diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c
index acd3f1e34ca6..98a5c23cf3df 100644
--- a/arch/i386/kernel/apic.c
+++ b/arch/i386/kernel/apic.c
@@ -75,8 +75,10 @@ void ack_bad_irq(unsigned int irq)
 	 * holds up an irq slot - in excessive cases (when multiple
 	 * unexpected vectors occur) that might lock up the APIC
 	 * completely.
+	 * But only ack when the APIC is enabled -AK
 	 */
-	ack_APIC_irq();
+	if (!cpu_has_apic)
+		ack_APIC_irq();
 }
 
 void __init apic_intr_init(void)
@@ -1303,6 +1305,7 @@ int __init APIC_init_uniprocessor (void)
 	if (!cpu_has_apic && APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) {
 		printk(KERN_ERR "BIOS bug, local APIC #%d not detected!...\n",
 			boot_cpu_physical_apicid);
+		clear_bit(X86_FEATURE_APIC, boot_cpu_data.x86_capability);
 		return -1;
 	}
 
diff --git a/arch/x86_64/kernel/apic.c b/arch/x86_64/kernel/apic.c
index c02218b3ae2b..6147770b4347 100644
--- a/arch/x86_64/kernel/apic.c
+++ b/arch/x86_64/kernel/apic.c
@@ -72,6 +72,26 @@ int get_maxlvt(void)
 	return maxlvt;
 }
 
+/*
+ * 'what should we do if we get a hw irq event on an illegal vector'.
+ * each architecture has to answer this themselves.
+ */
+void ack_bad_irq(unsigned int irq)
+{
+	printk("unexpected IRQ trap at vector %02x\n", irq);
+	/*
+	 * Currently unexpected vectors happen only on SMP and APIC.
+	 * We _must_ ack these because every local APIC has only N
+	 * irq slots per priority level, and a 'hanging, unacked' IRQ
+	 * holds up an irq slot - in excessive cases (when multiple
+	 * unexpected vectors occur) that might lock up the APIC
+	 * completely.
+  	 * But don't ack when the APIC is disabled. -AK
+	 */
+	if (!disable_apic)
+		ack_APIC_irq();
+}
+
 void clear_local_APIC(void)
 {
 	int maxlvt;
diff --git a/include/asm-x86_64/hardirq.h b/include/asm-x86_64/hardirq.h
index 8661b476fb40..8689951e3503 100644
--- a/include/asm-x86_64/hardirq.h
+++ b/include/asm-x86_64/hardirq.h
@@ -16,23 +16,6 @@
 #define set_softirq_pending(x) write_pda(__softirq_pending, (x))
 #define or_softirq_pending(x)  or_pda(__softirq_pending, (x))
 
-/*
- * 'what should we do if we get a hw irq event on an illegal vector'.
- * each architecture has to answer this themselves.
- */
-static inline void ack_bad_irq(unsigned int irq)
-{
-	printk("unexpected IRQ trap at vector %02x\n", irq);
-#ifdef CONFIG_X86_LOCAL_APIC
-	/*
-	 * Currently unexpected vectors happen only on SMP and APIC.
-	 * We _must_ ack these because every local APIC has only N
-	 * irq slots per priority level, and a 'hanging, unacked' IRQ
-	 * holds up an irq slot - in excessive cases (when multiple
-	 * unexpected vectors occur) that might lock up the APIC
-	 * completely.
-	 */
-	ack_APIC_irq();
-#endif
-}
+extern void ack_bad_irq(unsigned int irq);
+
 #endif /* __ASM_HARDIRQ_H */
-- 
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