diff --git a/redox-rt/src/protocol.rs b/redox-rt/src/protocol.rs
index 6161efe411..90032a5bd4 100644
--- a/redox-rt/src/protocol.rs
+++ b/redox-rt/src/protocol.rs
@@ -30,6 +30,16 @@ pub enum ProcCall {
     Setsid = 7,
     Kill = 8,
     Sigq = 9,
+
+    // TODO: replace with sendfd equivalent syscall for sending memory
+    SyncSigPctl = 10,
+}
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[repr(usize)]
+pub enum ThreadCall {
+    // TODO: replace with sendfd equivalent syscall for sending memory, or force userspace to
+    // obtain its TCB memory from this server
+    SyncSigTctl = 0,
 }
 
 impl ProcCall {
@@ -45,6 +55,15 @@ impl ProcCall {
             7 => Self::Setsid,
             8 => Self::Kill,
             9 => Self::Sigq,
+            10 => Self::SyncSigPctl,
+            _ => return None,
+        })
+    }
+}
+impl ThreadCall {
+    pub fn try_from_raw(raw: usize) -> Option<Self> {
+        Some(match raw {
+            0 => Self::SyncSigTctl,
             _ => return None,
         })
     }
diff --git a/redox-rt/src/signal.rs b/redox-rt/src/signal.rs
index f252ba5418..c7ac63dccd 100644
--- a/redox-rt/src/signal.rs
+++ b/redox-rt/src/signal.rs
@@ -1,12 +1,12 @@
 use core::{ffi::c_int, mem::MaybeUninit, ptr::NonNull, sync::atomic::Ordering};
 
 use syscall::{
-    data::AtomicU64, Error, RawAction, Result, RtSigInfo, SenderInfo, SetSighandlerData,
+    data::AtomicU64, CallFlags, Error, RawAction, Result, RtSigInfo, SenderInfo, SetSighandlerData,
     SigProcControl, Sigcontrol, SigcontrolFlags, TimeSpec, EAGAIN, EINTR, EINVAL, ENOMEM, EPERM,
     SIGCHLD, SIGKILL, SIGSTOP, SIGTSTP, SIGTTIN, SIGTTOU, SIGURG, SIGWINCH,
 };
 
-use crate::{arch::*, proc::FdGuard, sync::Mutex, RtTcb, Tcb};
+use crate::{arch::*, proc::FdGuard, protocol::{ProcCall, ThreadCall}, sync::Mutex, sys::{proc_call, thread_call}, RtTcb, Tcb};
 
 #[cfg(target_arch = "x86_64")]
 static CPUID_EAX1_ECX: core::sync::atomic::AtomicU32 = core::sync::atomic::AtomicU32::new(0);
@@ -576,6 +576,13 @@ pub fn setup_sighandler(tcb: &RtTcb) {
         syscall::dup(**tcb.thread_fd(), b"sighandler").expect("failed to open sighandler fd"),
     );
     let _ = syscall::write(*fd, &data).expect("failed to write to sighandler fd");
+    thread_call(&mut [], CallFlags::empty(), &[
+        ThreadCall::SyncSigTctl as usize,
+    ]);
+    // TODO: Only run for first thread
+    proc_call(&mut [], CallFlags::empty(), &[
+        ProcCall::SyncSigPctl as usize,
+    ]);
 
     // TODO: Inherited set of ignored signals
     set_sigmask(Some(0), None);
diff --git a/redox-rt/src/sys.rs b/redox-rt/src/sys.rs
index 8f299c0379..5d9bb146eb 100644
--- a/redox-rt/src/sys.rs
+++ b/redox-rt/src/sys.rs
@@ -10,11 +10,7 @@ use syscall::{
 };
 
 use crate::{
-    arch::manually_enter_trampoline,
-    proc::FdGuard,
-    protocol::{ProcCall, ProcKillTarget, WaitFlags},
-    signal::tmp_disable_signals,
-    DynamicProcInfo, Tcb, DYNAMIC_PROC_INFO,
+    arch::manually_enter_trampoline, proc::FdGuard, protocol::{ProcCall, ProcKillTarget, WaitFlags}, signal::tmp_disable_signals, DynamicProcInfo, RtTcb, Tcb, DYNAMIC_PROC_INFO
 };
 
 #[inline]
@@ -116,11 +112,11 @@ pub unsafe fn sys_futex_wake(addr: *mut u32, num: u32) -> Result<u32> {
     )
     .map(|awoken| awoken as u32)
 }
-fn proc_call(payload: &mut [u8], flags: CallFlags, metadata: &[usize]) -> Result<usize> {
+pub fn sys_call(fd: usize, payload: &mut [u8], flags: CallFlags, metadata: &[usize]) -> Result<usize> {
     unsafe {
         syscall::syscall5(
             syscall::SYS_CALL,
-            **crate::current_proc_fd(),
+            fd,
             payload.as_mut_ptr() as usize,
             payload.len(),
             metadata.len() | flags.bits(),
@@ -128,6 +124,12 @@ fn proc_call(payload: &mut [u8], flags: CallFlags, metadata: &[usize]) -> Result
         )
     }
 }
+pub fn proc_call(payload: &mut [u8], flags: CallFlags, metadata: &[usize]) -> Result<usize> {
+    sys_call(**crate::current_proc_fd(), payload, flags, metadata)
+}
+pub fn thread_call(payload: &mut [u8], flags: CallFlags, metadata: &[usize]) -> Result<usize> {
+    sys_call(**RtTcb::current().thread_fd(), payload, flags, metadata)
+}
 
 #[derive(Clone, Copy, Debug)]
 pub enum WaitpidTarget {