GCC implements the ARMv8-M Security Extensions as described in the ARMv8-M Security Extensions: Requirements on Development Tools Engineering Specification, which can be found at https://developer.arm.com/documentation/ecm0359818/latest/.
As part of the Security Extensions GCC implements two new function attributes:
As part of the Security Extensions GCC implements the intrinsics below. FPTR is used here to mean any function pointer type.
cmse_address_info_t cmse_TT (void *) cmse_address_info_t cmse_TT_fptr (FPTR) cmse_address_info_t cmse_TTT (void *) cmse_address_info_t cmse_TTT_fptr (FPTR) cmse_address_info_t cmse_TTA (void *) cmse_address_info_t cmse_TTA_fptr (FPTR) cmse_address_info_t cmse_TTAT (void *) cmse_address_info_t cmse_TTAT_fptr (FPTR) void * cmse_check_address_range (void *, size_t, int) typeof(p) cmse_nsfptr_create (FPTR p) intptr_t cmse_is_nsfptr (FPTR) int cmse_nonsecure_caller (void)