1 files changed, 15 insertions, 1 deletions

diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index b91411371ae1..ebfac782593f 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -523,7 +523,21 @@ int __init arm_add_memory(phys_addr_t start, unsigned long size)
          */
         size -= start & ~PAGE_MASK;
         bank->start = PAGE_ALIGN(start);
-        bank->size  = size & PAGE_MASK;
+
+#ifndef CONFIG_LPAE
+        if (bank->start + size < bank->start) {
+                printk(KERN_CRIT "Truncating memory at 0x%08llx to fit in "
+                        "32-bit physical address space\n", (long long)start);
+                /*
+                 * To ensure bank->start + bank->size is representable in
+                 * 32 bits, we use ULONG_MAX as the upper limit rather than 4GB.
+                 * This means we lose a page after masking.
+                 */
+                size = ULONG_MAX - bank->start;
+        }
+#endif
+
+        bank->size = size & PAGE_MASK;
 
         /*
          * Check whether this memory region has non-zero size or