diff --git a/openmp/runtime/CMakeLists.txt b/openmp/runtime/CMakeLists.txt
--- a/openmp/runtime/CMakeLists.txt
+++ b/openmp/runtime/CMakeLists.txt
@@ -66,7 +66,18 @@
   endif ()
   set(LIBOMP_ENABLE_ASSERTIONS ${LLVM_ENABLE_ASSERTIONS})
 endif()
-libomp_check_variable(LIBOMP_ARCH 32e x86_64 32 i386 arm ppc64 ppc64le aarch64 mic mips mips64 riscv64)
+
+# FUJITSU A64FX is a special processor because its cache line size is 256.
+# We need to pass this information into kmp_config.h.
+if(LIBOMP_ARCH STREQUAL "aarch64")
+  libomp_is_aarch64_a64fx(LIBOMP_DETECT_AARCH64_A64FX)
+  if (LIBOMP_DETECT_AARCH64_A64FX MATCHES "1")
+    set(LIBOMP_ARCH "aarch64_a64fx")
+    set(LIBOMP_ARCH_AARCH64_A64FX TRUE)
+  endif()
+endif()
+
+libomp_check_variable(LIBOMP_ARCH 32e x86_64 32 i386 arm ppc64 ppc64le aarch64 aarch64_a64fx mic mips mips64 riscv64)
 
 set(LIBOMP_LIB_TYPE normal CACHE STRING
   "Performance,Profiling,Stubs library (normal/profile/stubs)")
@@ -136,6 +147,7 @@
 set(INTEL64 FALSE)
 set(ARM FALSE)
 set(AARCH64 FALSE)
+set(AARCH64_A64FX FALSE)
 set(PPC64BE FALSE)
 set(PPC64LE FALSE)
 set(PPC64 FALSE)
@@ -157,6 +169,8 @@
   set(PPC64 TRUE)
 elseif("${LIBOMP_ARCH}" STREQUAL "aarch64") # AARCH64 architecture
   set(AARCH64 TRUE)
+elseif("${LIBOMP_ARCH}" STREQUAL "aarch64_a64fx") # AARCH64_A64FX architecture
+  set(AARCH64_A64FX TRUE)
 elseif("${LIBOMP_ARCH}" STREQUAL "mic") # Intel(R) Many Integrated Core Architecture
   set(MIC TRUE)
 elseif("${LIBOMP_ARCH}" STREQUAL "mips") # MIPS architecture
diff --git a/openmp/runtime/cmake/LibompGetArchitecture.cmake b/openmp/runtime/cmake/LibompGetArchitecture.cmake
--- a/openmp/runtime/cmake/LibompGetArchitecture.cmake
+++ b/openmp/runtime/cmake/LibompGetArchitecture.cmake
@@ -69,3 +69,78 @@
   # Remove ${detect_arch_src_txt} from cmake/ subdirectory
   file(REMOVE "${CMAKE_CURRENT_BINARY_DIR}/libomp_detect_arch.c")
 endfunction()
+
+function(libomp_is_aarch64_a64fx return_is_aarch64_a64fx)
+  set(detect_aarch64_a64fx_src_txt "
+    #include <stdio.h>
+
+    typedef struct aarch64_cpuid {
+      int implementer\;
+      int architecture\;
+      int variant\;
+      int partno\;
+      int revision\;
+    } aarch64_cpuid_t\;
+
+    int main(int argc, char *argv[]) {
+      char buf[256]\;
+      int value\;
+      FILE *f\;
+
+      aarch64_cpuid_t cpuid\;
+
+      cpuid.implementer = -1\;
+      cpuid.architecture = -1\;
+      cpuid.variant = -1\;
+      cpuid.partno = -1\;
+      cpuid.revision = -1\;
+
+      f = fopen(\"/proc/cpuinfo\", \"r\")\;
+      if (!f) {
+        printf(\"0\\n\")\;
+        return 0\;
+      }
+
+      while (fgets(buf, sizeof(buf), f)) {
+        if (sscanf(buf, \"CPU implementer : 0x%x\", &value) == 1) {
+          cpuid.implementer = value\;
+        } else if (sscanf(buf, \"CPU architecture : %d\", &value) == 1) {
+          cpuid.architecture = value\;
+        } else if (sscanf(buf, \"CPU variant : 0x%x\", &value) == 1) {
+          cpuid.variant = value\;
+        } else if (sscanf(buf, \"CPU part : 0x%x\", &value) == 1) {
+          cpuid.partno = value\;
+        } else if (sscanf(buf, \"CPU revision : %d\", &value) == 1) {
+          cpuid.revision = value\;
+        }
+
+        if ((cpuid.implementer != -1) && (cpuid.architecture != -1) &&
+            (cpuid.variant != -1) && (cpuid.partno != -1) &&
+            (cpuid.revision != -1)) {
+          break\;
+        }
+      }
+
+      fclose(f)\;
+
+      if (cpuid.implementer == 0x46 && cpuid.architecture == 8) {
+        printf(\"1\\n\")\;
+      } else {
+        printf(\"0\\n\")\;
+      }
+
+      return 0\;
+    }
+  ")
+
+  # Write out ${detect_a64fx_src_txt} to a file within the cmake/ subdirectory
+  file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/libomp_detect_aarch64_a64fx.c" ${detect_aarch64_a64fx_src_txt})
+
+  # Compile using the C Compiler.  It will always error out with an #error directive, so store error output to ${is_aarch64_a64fx}
+  try_run(run_dummy compile_dummy "${CMAKE_CURRENT_BINARY_DIR}" "${CMAKE_CURRENT_BINARY_DIR}/libomp_detect_aarch64_a64fx.c" RUN_OUTPUT_VARIABLE is_aarch64_a64fx)
+
+  set(${return_is_aarch64_a64fx} "${is_aarch64_a64fx}" PARENT_SCOPE)
+
+  # Remove ${detect_aarch64_a64fx_src_txt} from cmake/ subdirectory
+  file(REMOVE "${CMAKE_CURRENT_BINARY_DIR}/libomp_detect_aarch64_a64fx.c")
+endfunction(libomp_is_aarch64_a64fx)
diff --git a/openmp/runtime/cmake/LibompUtils.cmake b/openmp/runtime/cmake/LibompUtils.cmake
--- a/openmp/runtime/cmake/LibompUtils.cmake
+++ b/openmp/runtime/cmake/LibompUtils.cmake
@@ -101,6 +101,8 @@
     set(${return_arch_string} "PPC64LE" PARENT_SCOPE)
   elseif(${AARCH64})
     set(${return_arch_string} "AARCH64" PARENT_SCOPE)
+  elseif(${AARCH64_A64FX})
+    set(${return_arch_string} "AARCH64_A64FX" PARENT_SCOPE)
   elseif(${MIPS})
     set(${return_arch_string} "MIPS" PARENT_SCOPE)
   elseif(${MIPS64})
diff --git a/openmp/runtime/src/kmp_config.h.cmake b/openmp/runtime/src/kmp_config.h.cmake
--- a/openmp/runtime/src/kmp_config.h.cmake
+++ b/openmp/runtime/src/kmp_config.h.cmake
@@ -82,10 +82,14 @@
 #define KMP_HAVE_ATTRIBUTE_WAITPKG LIBOMP_HAVE_ATTRIBUTE_WAITPKG
 #cmakedefine01 LIBOMP_HAVE_ATTRIBUTE_RTM
 #define KMP_HAVE_ATTRIBUTE_RTM LIBOMP_HAVE_ATTRIBUTE_RTM
+#cmakedefine01 LIBOMP_ARCH_AARCH64_A64FX
+#define KMP_ARCH_AARCH64_A64FX LIBOMP_ARCH_AARCH64_A64FX
 
 // Configured cache line based on architecture
 #if KMP_ARCH_PPC64
 # define CACHE_LINE 128
+#elif KMP_ARCH_AARCH64_A64FX
+# define CACHE_LINE 256
 #else
 # define CACHE_LINE 64
 #endif