[PATCH] x86_64: Don't sync APIC ARBs on P4s.

Merged from i386

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/x86_64/kernel/apic.c b/arch/x86_64/kernel/apic.c
index cd37a0aa66f3e5bd0f78ff5c6dc7e43cf126aca0..dbccec4894c0b1b04b0e17834483f5443e00bb16 100644 (file)
--- a/arch/x86_64/kernel/apic.c
+++ b/arch/x86_64/kernel/apic.c
@@ -225,6 +225,11 @@ 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 */
+               return;
+
        /*
         * Wait for idle.
         */