ptos: ps: Add thread management groundwork

Signed-off-by: Chloe M <chloe@mensia.org>

service/ptos/head/ps/process.h

@@ -28,7 +28,7 @@
  * @Pid:        Process ID
  * @Flags:      Initialization flags
  */
-typedef struct {
+typedef struct _PROCESS {
     CHAR Name[PS_NAME_MAX];
     UQUAD Pid;
     ULONG Flags;

service/ptos/head/ps/thread.h

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2026, Chloe M.
+ * Provided under the BSD-3 clause.
+ *
+ * Description: Thread management
+ * Author:      Chloe M.
+ */
+
+#ifndef _PS_THREAD_H_
+#define _PS_THREAD_H_ 1
+
+#include <ptapi/status.h>
+#include <ptdef.h>
+#include <queue.h>
+
+#define THREAD_POOL_TAG 'TD'
+
+struct _PROCESS;
+
+/*
+ * Represents a runnable thread that exists within
+ * processes.
+ *
+ * @Tid:        Thread ID
+ * @ThreadLink: Thread queue link
+ */
+typedef struct _THREAD {
+    UQUAD Tid;
+    TAILQ_ENTRY(_THREAD) ThreadLink;
+} THREAD;
+
+/*
+ * Create a new thread
+ *
+ * @Parent:     Parent of thread to create
+ * @Flags:      Optional init flags
+ * @Result:     Result is written here
+ */
+PT_STATUS PsCreateThread(struct _PROCESS *Parent, ULONG Flags, THREAD **Result);
+
+#endif  /* !_PS_THREAD_H_ */

service/ptos/ps/thread.c

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2026, Chloe M.
+ * Provided under the BSD-3 clause.
+ *
+ * Description: Thread management
+ * Author:      Chloe M.
+ */
+
+#include <ps/thread.h>
+#include <ps/process.h>
+#include <ex/pool.h>
+#include <atomic.h>
+
+/* Globals */
+static UQUAD NextThreadTid = 0;
+
+PT_STATUS
+PsCreateThread(struct _PROCESS *Parent, ULONG Flags, THREAD **Result)
+{
+    THREAD *Thread;
+
+    if (Parent == NULL || Result == NULL) {
+        return STATUS_INVALID_PARAM;
+    }
+
+    Thread = ExAllocatePoolWithTag(
+        POOL_NON_PAGED,
+        sizeof(*Thread),
+        THREAD_POOL_TAG
+    );
+
+    if (Thread == NULL) {
+        return STATUS_NO_MEMORY;
+    }
+
+    Thread->Tid = AtomicIncQuad(&NextThreadTid);
+    *Result = Thread;
+    return STATUS_SUCCESS;
+}