xen64: get active_mm from the pda

x86_64 stores the active_mm in the pda, so fetch it from there.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 8 insertions, 1 deletions

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index d0976b87cd2c..2579e70cdd08 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -805,8 +805,15 @@ void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
 static void drop_other_mm_ref(void *info)
 {
         struct mm_struct *mm = info;
+        struct mm_struct *active_mm;
 
-        if (__get_cpu_var(cpu_tlbstate).active_mm == mm)
+#ifdef CONFIG_X86_64
+        active_mm = read_pda(active_mm);
+#else
+        active_mm = __get_cpu_var(cpu_tlbstate).active_mm;
+#endif
+
+        if (active_mm == mm)
                 leave_mm(smp_processor_id());
 
         /* If this cpu still has a stale cr3 reference, then make sure