diff --git a/arch/powerpc/include/asm/mmu-hash64.h b/arch/powerpc/include/asm/mmu-hash64.h
index 2fdb47a..f01fd9a 100644
--- a/arch/powerpc/include/asm/mmu-hash64.h
+++ b/arch/powerpc/include/asm/mmu-hash64.h
@@ -381,21 +381,37 @@ extern void slb_set_size(u16 size);
  * hash collisions.
  */
 
+/* This should go in Kconfig */
+/*
+ * Be careful with this value. This determines the VSID_MODULUS_*  and that
+ * need to be co-prime with VSID_MULTIPLIER*
+ */
+#if 1
+#define MAX_VIRTUAL_ADDR_BITS	65
+#else
+#define MAX_VIRTUAL_ADDR_BITS	66
+#endif
+/*
+ * One bit is taken by the kernel, only the rest of space is available for the
+ * user space.
+ */
+#define CONTEXT_BITS		(MAX_VIRTUAL_ADDR_BITS - \
+				 (USER_ESID_BITS + SID_SHIFT + 1))
+#define USER_ESID_BITS		18
+#define USER_ESID_BITS_1T	6
+
 /*
  * This should be computed such that protovosid * vsid_mulitplier
  * doesn't overflow 64 bits. It should also be co-prime to vsid_modulus
  */
 #define VSID_MULTIPLIER_256M	ASM_CONST(12538073)	/* 24-bit prime */
-#define VSID_BITS_256M		38
+#define VSID_BITS_256M		(CONTEXT_BITS + USER_ESID_BITS + 1)
 #define VSID_MODULUS_256M	((1UL<<VSID_BITS_256M)-1)
 
 #define VSID_MULTIPLIER_1T	ASM_CONST(12538073)	/* 24-bit prime */
-#define VSID_BITS_1T		26
+#define VSID_BITS_1T		(CONTEXT_BITS + USER_ESID_BITS_1T + 1)
 #define VSID_MODULUS_1T		((1UL<<VSID_BITS_1T)-1)
 
-#define CONTEXT_BITS		19
-#define USER_ESID_BITS		18
-#define USER_ESID_BITS_1T	6
 
 #define USER_VSID_RANGE	(1UL << (USER_ESID_BITS + SID_SHIFT))