Function sys_rt_sigprocmask 

pub fn sys_rt_sigprocmask(
    abi: &mut LinuxRiscv64Abi,
    trapframe: &mut Trapframe,
) -> usize

Linux rt_sigprocmask system call implementation

int rt_sigprocmask(int how, const sigset_t *set, sigset_t *oldset, size_t sigsetsize);