Remove CMake workaround for Arm Clang

Previous version of CMake did not allow CMAKE_SYSTEM_PROCESSOR
to contain CPU features for Arm Clang toolchain. A workaround
was added to manually strip the CPU features.

Recent versions of CMake have removed this limitation and instead
requires the toolchain to manually add -mcpu=<CPU+features>, which
means that the workaround can be removed.

Change-Id: I3e8647c47df27a96cdd103614ecf2540f150ab36
diff --git a/cmsis.cmake b/cmsis.cmake
index fd93545..daa8132 100644
--- a/cmsis.cmake
+++ b/cmsis.cmake
@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2019-2021 Arm Limited. All rights reserved.
+# Copyright (c) 2019-2022 Arm Limited.
 #
 # SPDX-License-Identifier: Apache-2.0
 #
@@ -17,20 +17,19 @@
 #
 
 # Extract the CPU number from the system processor
-string(REGEX MATCH "^cortex-m([0-9]+)$" CPU_NUMBER ${CMAKE_SYSTEM_PROCESSOR})
+string(REGEX REPLACE "^cortex-m([0-9]+[a-z]*)" "\\1" CPU_NUMBER ${CMAKE_SYSTEM_PROCESSOR})
 if(NOT CPU_NUMBER)
     message(FATAL_ERROR "System processor '${CMAKE_SYSTEM_PROCESSOR}' not supported. Should be cortex-m<nr>.")
 endif()
-string(REGEX REPLACE "^cortex-m([0-9]+)$" "\\1" CPU_NUMBER ${CMAKE_SYSTEM_PROCESSOR})
 
-set(ARM_CPU "ARMCM${CPU_NUMBER}")
+string(TOUPPER "ARMCM${CPU_NUMBER}" ARM_CPU)
 
 # Set CPU specific features
-if(${CMAKE_SYSTEM_PROCESSOR} STREQUAL "cortex-m33")
+if(CMAKE_SYSTEM_PROCESSOR MATCHES "cortex-m33")
     set(ARM_FEATURES "_DSP_FP")
-elseif(${CMAKE_SYSTEM_PROCESSOR} STREQUAL "cortex-m4")
+elseif(CMAKE_SYSTEM_PROCESSOR MATCHES  "cortex-m4")
     set(ARM_FEATURES "_FP")
-elseif(${CMAKE_SYSTEM_PROCESSOR} STREQUAL "cortex-m7")
+elseif(CMAKE_SYSTEM_PROCESSOR MATCHES  "cortex-m7")
     set(ARM_FEATURES "_DP")
 else()
     set(ARM_FEATURES "")
diff --git a/rtos/CMakeLists.txt b/rtos/CMakeLists.txt
index 753b307..6c91a83 100644
--- a/rtos/CMakeLists.txt
+++ b/rtos/CMakeLists.txt
@@ -24,12 +24,14 @@
 
 # Include ThreadX
 # Only enable cortex-m55 until cortex-m33 is sorted out upstream
-if((CMAKE_SYSTEM_PROCESSOR STREQUAL "cortex-m55") AND
+if((CMAKE_SYSTEM_PROCESSOR MATCHES "cortex-m55") AND
     (CORE_SOFTWARE_RTOS_LOWER STREQUAL "threadx" OR CORE_SOFTWARE_RTOS_LOWER STREQUAL "all"))
     #threadx build requires 2 defines: THREADX_ARCH (format: cortex_m4) and THREADX_TOOLCHAIN (ac5/ac6/gnu).
     #set them according to existing defines CMAKE_SYSTEM_PROCESSOR and CMAKE_CXX_COMPILER_ID:
-    string(REPLACE "-" "_" THREADX_ARCH ${CMAKE_SYSTEM_PROCESSOR})
+    string(REGEX MATCH "^cortex-m([0-9]+[a-z]*)" THREADX_ARCH ${CMAKE_SYSTEM_PROCESSOR})
+    string(REPLACE "-" "_" THREADX_ARCH ${THREADX_ARCH})
     string(TOLOWER ${CMAKE_CXX_COMPILER_ID} THREADX_TOOLCHAIN)
+
     #if armclang, change the format to "ac6".
     if(THREADX_TOOLCHAIN STREQUAL "armclang")
         set(THREADX_TOOLCHAIN "ac6")
diff --git a/rtos/freertos_config/CMakeLists.txt b/rtos/freertos_config/CMakeLists.txt
index 318390d..554a492 100644
--- a/rtos/freertos_config/CMakeLists.txt
+++ b/rtos/freertos_config/CMakeLists.txt
@@ -16,23 +16,23 @@
 # limitations under the License.
 #
 
-if(CMAKE_SYSTEM_PROCESSOR STREQUAL "cortex-m3")
+if(CMAKE_SYSTEM_PROCESSOR MATCHES "cortex-m3")
     add_compile_definitions(CPU_CORTEX_M3)
-elseif(CMAKE_SYSTEM_PROCESSOR STREQUAL "cortex-m33")
+elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "cortex-m33")
     add_compile_definitions(CPU_CORTEX_M33)
-elseif(CMAKE_SYSTEM_PROCESSOR STREQUAL "cortex-m4")
+elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "cortex-m4")
     add_compile_definitions(CPU_CORTEX_M4)
-elseif(CMAKE_SYSTEM_PROCESSOR STREQUAL "cortex-m55")
+elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "cortex-m55")
     add_compile_definitions(CPU_CORTEX_M55)
-elseif(CMAKE_SYSTEM_PROCESSOR STREQUAL "cortex-m7")
+elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "cortex-m7")
     add_compile_definitions(CPU_CORTEX_M7)
-elseif(CMAKE_SYSTEM_PROCESSOR STREQUAL "cortex-m85")
+elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "cortex-m85")
     add_compile_definitions(CPU_CORTEX_M85)
 else()
     message(FATAL_ERROR "Unsupported compiler ${CMAKE_SYSTEM_PROCESSOR}.")
 endif()
 
-if((${TARGET} STREQUAL "mps2") OR (${CMAKE_SYSTEM_PROCESSOR} STREQUAL "cortex-m55"))
+if((${TARGET} STREQUAL "mps2") OR (${CMAKE_SYSTEM_PROCESSOR} MATCHES "cortex-m55"))
     set("SYSTEM_CORE_CLOCK" "25000000")
 else()
     set("SYSTEM_CORE_CLOCK" "32000000")
@@ -66,28 +66,28 @@
 target_sources(freertos_kernel PRIVATE
     ${FREERTOS_KERNEL_PATH}/portable/MemMang/heap_3.c)
 
-if(${CMAKE_SYSTEM_PROCESSOR} STREQUAL "cortex-m3")
+if(${CMAKE_SYSTEM_PROCESSOR} MATCHES "cortex-m3")
 target_sources(freertos_kernel PRIVATE
     ${FREERTOS_KERNEL_PATH}/portable/GCC/ARM_CM3/port.c
 )
 target_include_directories(freertos_kernel PUBLIC
     ${FREERTOS_KERNEL_PATH}/portable/GCC/ARM_CM3
 )
-elseif(${CMAKE_SYSTEM_PROCESSOR} STREQUAL "cortex-m4")
+elseif(${CMAKE_SYSTEM_PROCESSOR} MATCHES "cortex-m4")
     target_sources(freertos_kernel PRIVATE
         ${FREERTOS_KERNEL_PATH}/portable/GCC/ARM_CM4F/port.c
     )
     target_include_directories(freertos_kernel PUBLIC
         ${FREERTOS_KERNEL_PATH}/portable/GCC/ARM_CM4F
     )
-elseif(${CMAKE_SYSTEM_PROCESSOR} STREQUAL "cortex-m7")
+elseif(${CMAKE_SYSTEM_PROCESSOR} MATCHES "cortex-m7")
     target_sources(freertos_kernel PRIVATE
         ${FREERTOS_KERNEL_PATH}/portable/GCC/ARM_CM7/r0p1/port.c
     )
     target_include_directories(freertos_kernel PUBLIC
         ${FREERTOS_KERNEL_PATH}/portable/GCC/ARM_CM7/r0p1
     )
-elseif(${CMAKE_SYSTEM_PROCESSOR} STREQUAL "cortex-m33")
+elseif(${CMAKE_SYSTEM_PROCESSOR} MATCHES "cortex-m33")
     target_sources(freertos_kernel PRIVATE
         ${FREERTOS_KERNEL_PATH}/portable/GCC/ARM_CM33_NTZ/non_secure/port.c
         ${FREERTOS_KERNEL_PATH}/portable/GCC/ARM_CM33_NTZ/non_secure/portasm.c
@@ -95,7 +95,7 @@
     target_include_directories(freertos_kernel PUBLIC
         ${FREERTOS_KERNEL_PATH}/portable/GCC/ARM_CM33_NTZ/non_secure
     )
-elseif(${CMAKE_SYSTEM_PROCESSOR} STREQUAL "cortex-m55")
+elseif(${CMAKE_SYSTEM_PROCESSOR} MATCHES "cortex-m55")
 # TODO: using the same port files as Cortex-M33. Update for Cortex-M55.
     target_sources(freertos_kernel PRIVATE
         ${FREERTOS_KERNEL_PATH}/portable/GCC/ARM_CM33_NTZ/non_secure/port.c
@@ -104,7 +104,7 @@
     target_include_directories(freertos_kernel PUBLIC
         ${FREERTOS_KERNEL_PATH}/portable/GCC/ARM_CM33_NTZ/non_secure
     )
-elseif(${CMAKE_SYSTEM_PROCESSOR} STREQUAL "cortex-m85")
+elseif(${CMAKE_SYSTEM_PROCESSOR} MATCHES "cortex-m85")
 # TODO: using the same port files as Cortex-M33. Update for Cortex-M85.
     target_sources(freertos_kernel PRIVATE
         ${FREERTOS_KERNEL_PATH}/portable/GCC/ARM_CM33_NTZ/non_secure/port.c