SYS_PMSIDR_EL1
mrs_s x1, SYS_PMSIDR_EL1
(read_sysreg_s(SYS_PMSIDR_EL1) & PMSIDR_EL1_FDS));
{ SYS_DESC(SYS_PMSIDR_EL1), undef_access },
reg = read_sysreg_s(SYS_PMSIDR_EL1);