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)
+    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 +69,16 @@
   # 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)
+  file(READ "/proc/cpuinfo" cpu_info_content)
+  string(REGEX MATCH "CPU implementer[ \t]*: 0x46\n" cpu_implementer ${cpu_info_content})
+  string(REGEX MATCH "CPU architecture[ \t]*: 8\n" cpu_architecture ${cpu_info_content})
+
+  set(is_aarch64_a64fx FALSE)
+  if (cpu_architecture AND cpu_implementer)
+    set(is_aarch64_a64fx TRUE)
+  endif()
+
+  set(${return_is_aarch64_a64fx} "${is_aarch64_a64fx}" PARENT_SCOPE)
+endfunction(libomp_is_aarch64_a64fx)
diff --git a/openmp/runtime/cmake/LibompUtils.cmake b/openmp/runtime/cmake/LibompUtils.cmake
--- a/openmp/runtime/cmake/LibompUtils.cmake
+++ b/openmp/runtime/cmake/LibompUtils.cmake
@@ -101,6 +101,8 @@
     set(${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/cmake/config-ix.cmake b/openmp/runtime/cmake/config-ix.cmake
--- a/openmp/runtime/cmake/config-ix.cmake
+++ b/openmp/runtime/cmake/config-ix.cmake
@@ -291,6 +291,7 @@
       (LIBOMP_ARCH STREQUAL i386) OR
 #      (LIBOMP_ARCH STREQUAL arm) OR
       (LIBOMP_ARCH STREQUAL aarch64) OR
+      (LIBOMP_ARCH STREQUAL aarch64_a64fx) OR
       (LIBOMP_ARCH STREQUAL ppc64le) OR
       (LIBOMP_ARCH STREQUAL ppc64) OR
       (LIBOMP_ARCH STREQUAL riscv64))
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