[PATCH 5/5] xen: arm: correctly round down MFN to 1GB boundary make sure pagetable mask macros as physaddr size

[Ian Campbell <ian.campbell@citrix.com>]

~FIRST_MASK is nothing like correct for rounding down an MFN. It is the
inverse *and* an address not a framenumber so wrong in every dimension! We
cannot use FIRST_MASK since that would mask off any zeroeth level bits.
Instead calculate the correct value from FIRST_SIZE.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
---
 xen/arch/arm/mm.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index e48d473..887930a 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -656,7 +656,7 @@ void __init setup_xenheap_mappings(unsigned long base_mfn,
     end_mfn = base_mfn + nr_mfns;
 
     /* Align to previous 1GB boundary */
-    base_mfn &= ~FIRST_MASK;
+    base_mfn &= ~((FIRST_SIZE>>PAGE_SHIFT)-1);
 
     offset = base_mfn - xenheap_mfn_start;
     vaddr = DIRECTMAP_VIRT_START + offset*PAGE_SIZE;
-- 
1.7.10.4