[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>
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 @@
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 @@
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 @@
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.