diff --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt
--- a/llvm/CMakeLists.txt
+++ b/llvm/CMakeLists.txt
@@ -557,6 +557,22 @@
   option(LLVM_BUILD_32_BITS "Build 32 bits executables and libraries." OFF)
 endif()
 
+set(LLVM_SYS_PAGE_SIZE "4K" CACHE STRING
+  "Define the system page size used to update ring buffer in HWasan.")
+if( LLVM_SYS_PAGE_SIZE STREQUAL "4K")
+  add_definitions(-DSYS_PAGE_SIZE_4K)
+endif()
+if( LLVM_SYS_PAGE_SIZE STREQUAL "8K")
+  add_definitions(-DSYS_PAGE_SIZE_8K)
+endif()
+if( LLVM_SYS_PAGE_SIZE STREQUAL "16K")
+  add_definitions(-DSYS_PAGE_SIZE_16K)
+endif()
+if( LLVM_SYS_PAGE_SIZE STREQUAL "64K")
+  add_definitions(-DSYS_PAGE_SIZE_64K)
+endif()
+
+
 # Define the default arguments to use with 'lit', and an option for the user to
 # override.
 set(LIT_ARGS_DEFAULT "-sv")