--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/arch/x86/include/asm/mmu_context_64.h	Sun Jan 11 20:20:11 2009 +0100
@@ -0,0 +1,54 @@
+#ifndef _ASM_X86_MMU_CONTEXT_64_H
+#define _ASM_X86_MMU_CONTEXT_64_H
+
+#include <asm/pda.h>
+
+static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
+{
+#ifdef CONFIG_SMP
+	if (read_pda(mmu_state) == TLBSTATE_OK)
+		write_pda(mmu_state, TLBSTATE_LAZY);
+#endif
+}
+
+static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
+			     struct task_struct *tsk)
+{
+	unsigned cpu = smp_processor_id();
+	if (likely(prev != next)) {
+		/* stop flush ipis for the previous mm */
+		cpu_clear(cpu, prev->cpu_vm_mask);
+#ifdef CONFIG_SMP
+		write_pda(mmu_state, TLBSTATE_OK);
+		write_pda(active_mm, next);
+#endif
+		cpu_set(cpu, next->cpu_vm_mask);
+		load_cr3(next->pgd);
+
+		if (unlikely(next->context.ldt != prev->context.ldt))
+			load_LDT_nolock(&next->context);
+	}
+#ifdef CONFIG_SMP
+	else {
+		write_pda(mmu_state, TLBSTATE_OK);
+		if (read_pda(active_mm) != next)
+			BUG();
+		if (!cpu_test_and_set(cpu, next->cpu_vm_mask)) {
+			/* We were in lazy tlb mode and leave_mm disabled
+			 * tlb flush IPI delivery. We must reload CR3
+			 * to make sure to use no freed page tables.
+			 */
+			load_cr3(next->pgd);
+			load_LDT_nolock(&next->context);
+		}
+	}
+#endif
+}
+
+#define deactivate_mm(tsk, mm)			\
+do {						\
+	load_gs_index(0);			\
+	asm volatile("movl %0,%%fs"::"r"(0));	\
+} while (0)
+
+#endif /* _ASM_X86_MMU_CONTEXT_64_H */