1 files changed, 17 insertions, 7 deletions

diff --git a/include/asm-parisc/tlbflush.h b/include/asm-parisc/tlbflush.h
index eb27b78930e8..c9ec39c6fc6c 100644
--- a/include/asm-parisc/tlbflush.h
+++ b/include/asm-parisc/tlbflush.h
@@ -7,6 +7,20 @@
 #include <linux/mm.h>
 #include <asm/mmu_context.h>
 
+
+/* This is for the serialisation of PxTLB broadcasts.  At least on the
+ * N class systems, only one PxTLB inter processor broadcast can be
+ * active at any one time on the Merced bus.  This tlb purge
+ * synchronisation is fairly lightweight and harmless so we activate
+ * it on all SMP systems not just the N class.  We also need to have
+ * preemption disabled on uniprocessor machines, and spin_lock does that
+ * nicely.
+ */
+extern spinlock_t pa_tlb_lock;
+
+#define purge_tlb_start(x) spin_lock(&pa_tlb_lock)
+#define purge_tlb_end(x) spin_unlock(&pa_tlb_lock)
+
 extern void flush_tlb_all(void);
 
 /*
@@ -64,29 +78,25 @@ static inline void flush_tlb_range(struct vm_area_struct *vma,
 {
         unsigned long npages;
 
-        
         npages = ((end - (start & PAGE_MASK)) + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
-        if (npages >= 512)  /* XXX arbitrary, should be tuned */
+        if (npages >= 512)  /* 2MB of space: arbitrary, should be tuned */
                 flush_tlb_all();
         else {
-
                 mtsp(vma->vm_mm->context,1);
+                purge_tlb_start();
                 if (split_tlb) {
-                        purge_tlb_start();
                         while (npages--) {
                                 pdtlb(start);
                                 pitlb(start);
                                 start += PAGE_SIZE;
                         }
-                        purge_tlb_end();
                 } else {
-                        purge_tlb_start();
                         while (npages--) {
                                 pdtlb(start);
                                 start += PAGE_SIZE;
                         }
-                        purge_tlb_end();
                 }
+                purge_tlb_end();
         }
 }