diff --git a/src/process.rs b/src/process.rs
index a0e47234..2e20f6d9 100644
--- a/src/process.rs
+++ b/src/process.rs
@@ -1,6 +1,6 @@
 //! Data structures for process management
 
-use core::num::NonZeroI32;
+use core::{num::NonZeroI32, time::Duration};
 
 use crate::{arch::SavedFrame, impl_place_lifetime, io::RawFd, primitive_enum};
 
@@ -68,6 +68,31 @@ pub struct SpawnOptions<'a> {
     pub optional: &'a [SpawnOption],
 }
 
+/// Controls how threads are spawned within a process
+#[derive(Clone, Debug)]
+#[repr(C)]
+pub struct ThreadSpawnOptions {
+    /// Thread entry function
+    pub entry: extern "C" fn(u64) -> !,
+    /// Thread argument value
+    pub argument: u64,
+    /// Thread stack pointer. NOTE: it's the caller's responsibility to allocate a proper stack for
+    /// the thread.
+    pub stack_top: usize,
+}
+
+/// Describes a single mutex operation
+#[derive(Clone, Debug)]
+#[repr(C)]
+pub enum MutexOperation {
+    /// Waits on the mutex object until it is different from "compare value"
+    Wait(u32, Option<Duration>),
+    /// Wakes a single mutex-waiting thread
+    Wake,
+    /// Wakes all threads waiting on the mutex
+    WakeAll,
+}
+
 // TODO not sure if I really need #[repr(C)] ABI here
 impl_place_lifetime! {
     #[doc = "Argument struct passed from the kernel to a spawned process"]
diff --git a/src/syscall.rs b/src/syscall.rs
index a5d37131..d8a59483 100644
--- a/src/syscall.rs
+++ b/src/syscall.rs
@@ -4,7 +4,7 @@ use crate::primitive_enum;
 primitive_enum!(
     #[doc = "Describes a system call issued to the kernel"]
     pub enum SyscallFunction: usize {
-        #[doc = "Terminate the caller task"]
+        #[doc = "Terminate the caller thread"]
         Exit = 1,
         #[doc = "Suspend the caller task for some time"]
         Nanosleep = 2,
@@ -49,6 +49,10 @@ primitive_enum!(
         SetProcessGroupId = 45,
         #[doc = "Start a new session and set the caller process as its leader"]
         StartSession = 46,
+        #[doc = "Create and start a new thread within the caller's process"]
+        SpawnThread = 47,
+        #[doc = "Mutex operation: wait, wake, etc."]
+        Mutex = 48,
 
         #[doc = "Send a signal to a process"]
         SendSignal = 50,