[PATCH] i386: Replace broken serialize_cpu in microcode driver with correct sync_core

Passing random input values in eax to cpuid is not a good idea
because the CPU will GPF for unknown ones.
Use the correct x86-64 version that exists for a longer time too.
This also adds a memory barrier to prevent the optimizer from
reordering.

Cc: tigran@veritas.com

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/i386/kernel/microcode.c b/arch/i386/kernel/microcode.c
index fad3037..d3fdf00 100644
--- a/arch/i386/kernel/microcode.c
+++ b/arch/i386/kernel/microcode.c
@@ -166,7 +166,7 @@
 
 	wrmsr(MSR_IA32_UCODE_REV, 0, 0);
 	/* see notes above for revision 1.07.  Apparent chip bug */
-	serialize_cpu();
+	sync_core();
 	/* get the current revision from MSR 0x8B */
 	rdmsr(MSR_IA32_UCODE_REV, val[0], uci->rev);
 	pr_debug("microcode: collect_cpu_info : sig=0x%x, pf=0x%x, rev=0x%x\n",
@@ -380,7 +380,7 @@
 	wrmsr(MSR_IA32_UCODE_REV, 0, 0);
 
 	/* see notes above for revision 1.07.  Apparent chip bug */
-	serialize_cpu();
+	sync_core();
 
 	/* get the current revision from MSR 0x8B */
 	rdmsr(MSR_IA32_UCODE_REV, val[0], val[1]);