diff --git a/arch/powerpc/include/asm/mmu-hash64.h b/arch/powerpc/include/asm/mmu-hash64.h
index 0e08252..3e297ea 100644
--- a/arch/powerpc/include/asm/mmu-hash64.h
+++ b/arch/powerpc/include/asm/mmu-hash64.h
@@ -22,6 +22,13 @@
  */
 #include <asm/pgtable-ppc64.h>
 
+#ifdef CONFIG_DEBUG_VM
+#ifndef __ASSEMBLY__
+#include <asm/udbg.h>
+#include <asm/bug.h>
+#endif
+#endif
+
 /*
  * Segment table
  */
@@ -522,11 +529,32 @@ static inline int user_segment_size(unsigned long addr)
 static inline unsigned long get_vsid(unsigned long context, unsigned long ea,
 				     int ssize)
 {
-	if (ssize == MMU_SEGSIZE_256M)
-		return vsid_scramble((context << USER_ESID_BITS)
-				     | (ea >> SID_SHIFT), 256M);
-	return vsid_scramble((context << USER_ESID_BITS_1T)
-			     | (ea >> SID_SHIFT_1T), 1T);
+	if (ssize == MMU_SEGSIZE_256M) {
+		context = context << USER_ESID_BITS;
+		ea = ea >> SID_SHIFT;
+#ifdef CONFIG_DEBUG_VM
+		/*
+		 * context and ea should not overlap.
+		 */
+		if (context & ea) {
+			udbg_printf("Overlapping bits %lx %lx\n", context, ea);
+			WARN_ON(1);
+		}
+#endif
+		return vsid_scramble(context | ea, 256M);
+	}
+	context = context << USER_ESID_BITS_1T;
+	ea = ea >> SID_SHIFT_1T;
+#ifdef CONFIG_DEBUG_VM
+	/*
+	 * context and ea should not overlap.
+	 */
+	if (context & ea) {
+		udbg_printf("Overlapping bits for 1T %lx %lx\n", context, ea);
+		WARN_ON(1);
+	}
+#endif
+	return vsid_scramble(context | ea, 1T);
 }
 
 /*
@@ -540,11 +568,20 @@ static inline unsigned long get_vsid(unsigned long context, unsigned long ea,
  */
 static inline unsigned long get_kernel_vsid(unsigned long ea, int ssize)
 {
+	unsigned int c_index;
 	unsigned long context;
 	/*
 	 * kernel take the top 4 context from the available range
 	 */
-	context = (MAX_CONTEXT - 4) +  ((ea >> 60) - 0xc);
+	c_index =   ((ea >> 60) - 0xc);
+	context = (MAX_CONTEXT - 4) + c_index;
+#ifdef CONFIG_DEBUG_VM
+	/*
+	 * Drop the c_index related bits from ea, so we get
+	 * non overlapping context and ea.
+	 */
+	ea = ea - ((0xcUL + c_index) << 60);
+#endif
 	return get_vsid(context, ea, ssize);
 }
 #endif /* __ASSEMBLY__ */