An arch should select this symbol if it provides all of these things:
- syscall_get_arch()
- syscall_get_arguments()
- syscall_rollback()
- syscall_set_return_value()
- SIGSYS siginfo_t support
- secure_computing is called from a ptrace_event()-safe context
- secure_computing return value is checked and a return value of -1
results in the system call being skipped immediately.
- seccomp syscall wired up

For best performance, an arch should use seccomp_phase1 and
seccomp_phase2 directly. It should call seccomp_phase1 for all
syscalls if TIF_SECCOMP is set, but seccomp_phase1 does not
need to be called from a ptrace-safe context. It must then
call seccomp_phase2 if seccomp_phase1 returns anything other
than SECCOMP_PHASE1_OK or SECCOMP_PHASE1_SKIP.

As an additional optimization, an arch may provide seccomp_data
directly to seccomp_phase1; this avoids multiple calls
to the syscall_xyz helpers for every syscall.