diff --git a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
--- a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
@@ -78,6 +78,11 @@
 
 static const unsigned kShadowBaseAlignment = 32;
 
+static cl::opt<std::string> ClSystemPageSize(
+    "hwasan-sys-page-size",
+    cl::desc("System page size for ring buffer, such as 4K/8K/16K/64K"),
+    cl::Hidden, cl::init("4k"));
+
 static cl::opt<std::string>
     ClMemoryAccessCallbackPrefix("hwasan-memory-access-callback-prefix",
                                  cl::desc("Prefix for memory access callbacks"),
@@ -246,6 +251,20 @@
   return ClUseAfterScope && shouldInstrumentStack(TargetTriple);
 }
 
+static uint64_t getSystemPageSizeBits() {
+  StringRef PageSizeStr(ClSystemPageSize.getValue());
+  if (PageSizeStr.equals_insensitive("4k"))
+    return 12;
+  else if (PageSizeStr.equals_insensitive("8k"))
+    return 13;
+  else if (PageSizeStr.equals_insensitive("16k"))
+    return 14;
+  else if (PageSizeStr.equals_insensitive("64k"))
+    return 16;
+  else
+    report_fatal_error("unsupported page size: " + PageSizeStr);
+}
+
 /// An instrumentation pass implementing detection of addressability bugs
 /// using tagged pointers.
 class HWAddressSanitizer {