sched: implement user-configurable fs and gs segment base addresses

syscall/task.c

@@ -287,3 +287,75 @@ kern_status_t sys_thread_start(kern_handle_t thread_handle)
 
 	return KERN_OK;
 }
+
+kern_status_t sys_thread_config_get(
+	kern_handle_t thread_handle,
+	kern_config_key_t key,
+	void *ptr,
+	size_t len)
+{
+	unsigned long flags;
+	struct task *self = current_task();
+
+	if (!validate_access_w(self, ptr, len)) {
+		return KERN_MEMORY_FAULT;
+	}
+
+	struct object *thread_obj;
+	handle_flags_t thread_flags;
+	task_lock_irqsave(self, &flags);
+	kern_status_t status = task_resolve_handle(
+		self,
+		thread_handle,
+		&thread_obj,
+		&thread_flags);
+	if (status != KERN_OK) {
+		task_unlock_irqrestore(self, flags);
+		return status;
+	}
+
+	struct thread *thread = thread_cast(thread_obj);
+	task_unlock_irqrestore(self, flags);
+
+	status = thread_config_get(thread, key, ptr, len);
+
+	object_unref(thread_obj);
+
+	return status;
+}
+
+kern_status_t sys_thread_config_set(
+	kern_handle_t thread_handle,
+	kern_config_key_t key,
+	const void *ptr,
+	size_t len)
+{
+	unsigned long flags;
+	struct task *self = current_task();
+
+	if (!validate_access_w(self, ptr, len)) {
+		return KERN_MEMORY_FAULT;
+	}
+
+	struct object *thread_obj;
+	handle_flags_t thread_flags;
+	task_lock_irqsave(self, &flags);
+	kern_status_t status = task_resolve_handle(
+		self,
+		thread_handle,
+		&thread_obj,
+		&thread_flags);
+	if (status != KERN_OK) {
+		task_unlock_irqrestore(self, flags);
+		return status;
+	}
+
+	struct thread *thread = thread_cast(thread_obj);
+	task_unlock_irqrestore(self, flags);
+
+	status = thread_config_set(thread, key, ptr, len);
+
+	object_unref(thread_obj);
+
+	return status;
+}