1 files changed, 6 insertions, 1 deletions
diff --git a/libc/bionic/mmap.cpp b/libc/bionic/mmap.cpp
index 8f25a89..53e8b46 100644
--- a/libc/bionic/mmap.cpp
+++ b/libc/bionic/mmap.cpp
@@ -36,6 +36,11 @@
 extern "C" void*  __mmap2(void*, size_t, int, int, int, size_t);
 
 #define MMAP2_SHIFT 12 // 2**12 == 4096
+#ifdef LEGACY_MMAP
+#define TO_64(a) ((a) & 0x00000000ffffffff)
+#else
+#define TO_64(a) (a)
+#endif
 
 static bool kernel_has_MADV_MERGEABLE = true;
 
@@ -60,5 +65,5 @@ void* mmap64(void* addr, size_t size, int prot, int flags, int fd, off64_t offse
 }
 
 void* mmap(void* addr, size_t size, int prot, int flags, int fd, off_t offset) {
-  return mmap64(addr, size, prot, flags, fd, static_cast<off64_t>(offset));
+  return mmap64(addr, size, prot, flags, fd, TO_64(static_cast<off64_t>(offset)));
 }