[PATCH] i386: Consolidate modern APIC handling

AMD systems have a modern APIC that supports 8 bit IDs, but
don't have a XAPIC version number.  Add a new "modern_apic"
subfunction that handles this correctly and use it (nearly)
everywhere where XAPIC is tested for.

I removed one wart: the code specified that external APICs
would use an 8bit APIC ID. But I checked a real 82093 data sheet
and it says clearly that they only use 4bit. So I removed
this special case since it would a bit awkward to implement now.

I removed the valid APIC tests in mptable parsing completely. On any modern
system they only check against the full field width (8bit) anyways
and are no-ops. This also fixes them doing the wrong thing
on >8 core Opterons.

This makes i386 boot again on 16 core Opterons.

Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 16 insertions, 7 deletions

diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c
index 6273bf7..254cee9 100644
--- a/arch/i386/kernel/apic.c
+++ b/arch/i386/kernel/apic.c
@@ -62,6 +62,18 @@ int apic_verbosity;
 
 static void apic_pm_activate(void);
 
+int modern_apic(void)
+{
+	unsigned int lvr, version;
+	/* AMD systems use old APIC versions, so check the CPU */
+	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
+		boot_cpu_data.x86 >= 0xf)
+		return 1;
+	lvr = apic_read(APIC_LVR);
+	version = GET_APIC_VERSION(lvr);
+	return version >= 0x14;
+}
+
 /*
  * 'what should we do if we get a hw irq event on an illegal vector'.
  * each architecture has to answer this themselves.
@@ -119,10 +131,7 @@ void enable_NMI_through_LVT0 (void * dummy)
 
 int get_physical_broadcast(void)
 {
-	unsigned int lvr, version;
-	lvr = apic_read(APIC_LVR);
-	version = GET_APIC_VERSION(lvr);
-	if (!APIC_INTEGRATED(version) || version >= 0x14)
+	if (modern_apic())
 		return 0xff;
 	else
 		return 0xf;
@@ -349,9 +358,9 @@ int __init verify_local_APIC(void)
 
 void __init sync_Arb_IDs(void)
 {
-	/* Unsupported on P4 - see Intel Dev. Manual Vol. 3, Ch. 8.6.1 */
-	unsigned int ver = GET_APIC_VERSION(apic_read(APIC_LVR));
-	if (ver >= 0x14)	/* P4 or higher */
+	/* Unsupported on P4 - see Intel Dev. Manual Vol. 3, Ch. 8.6.1
+	   And not needed on AMD */
+	if (modern_apic())
 		return;
 	/*
 	 * Wait for idle.