csrts: Add CSRTS stub and load from kernel

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

build.sh

@@ -72,6 +72,10 @@ build() {
         service/urt/    \
         "Building user runtime lib..."
 
+    make_build          \
+        service/csrts   \
+        "Building CSRTS..."
+
     make_build          \
         service/ptos/   \
         "Building kernel..."

service/csrts/Makefile

@@ -0,0 +1,16 @@
+#
+# Copyright (c) 2026, Chloe M.
+# Provided under the BSD-3 clause
+#
+# Description:  Client server runtime service build script
+# Author:       Chloe M.
+#
+
+include ../mk/user.mk
+
+.PHONY: all
+all: server
+
+.PHONY: server
+server:
+	cd server/; $(MAKE) $(PASSDOWN_ARGS)

service/csrts/server/Makefile

@@ -0,0 +1,26 @@
+#
+# Copyright (c) 2026, Chloe M.
+# Provided under the BSD-3 clause
+#
+# Description:  Client server runtime service build script
+# Author:       Chloe M.
+#
+
+CFILES = $(shell find . -name "*.c")
+OFILES = $(CFILES:.c=.o)
+
+CFLAGS = $(SYS_CFLAGS)
+CRT_FILES = $(shell find $(PT_URT_CRT) -name "*.o")
+
+SERVER_OUT = \
+	$(PT_PROJECT_ROOT)/service/base/boot/csrts.sys
+
+.PHONY: all
+all: $(SERVER_OUT)
+
+.PHONY: $(SERVER_OUT)
+$(SERVER_OUT): $(OFILES)
+	$(SYS_LD) $(OFILES) $(CRT_FILES) -T$(USER_LDS) -o $@
+
+%.o: %.c
+	$(SYS_CC) -c $< $(CFLAGS) -o $@

service/csrts/server/init.c

@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2026, Chloe M.
+ * Provided under the BSD-3 clause.
+ *
+ * Description: CSRTS init
+ * Author:      Chloe M.
+ */
+
+#include <ptdef.h>
+
+VOID
+Main(VOID)
+{
+}

service/ptos/ke/init.c

@@ -12,7 +12,9 @@
 #include <ke/sched.h>
 #include <ex/trace.h>
 #include <ex/pbi.h>
+#include <ex/loader.h>
 #include <ps/process.h>
+#include <ps/thread.h>
 #include <mm/pm.h>
 #include <mm/vm.h>
 #include <hal/prim.h>
@@ -26,6 +28,7 @@
 /* Globals */
 static KPCR BootstrapCore;
 static PROCESS *RootProcess;
+static THREAD *RootThread;
 
 /*
  * Display the copyright for legal reasons
@@ -44,11 +47,13 @@ static VOID
 InitializeRootProcess(VOID)
 {
     PT_STATUS Status;
+    PBI_FILE File;
+    LOADER_PROGRAM Csrts;
 
     /* Create the client server runtime service */
     Status = PsCreateProcess(
         "csrts.sys",
-        0,
+        PS_USER,
         &RootProcess
     );
 
@@ -58,6 +63,39 @@ InitializeRootProcess(VOID)
             "could not create csrts.sys process\n"
         );
     }
+
+    /* Get the CSRTS binary */
+    Status = ExPbiLookup("/boot/csrts.sys", &File);
+    if (PT_ERROR(Status)) {
+        KeBugCheck(
+            BUGCHECK_MISC,
+            "unable to locate /boot/csrts.sys\n"
+        );
+    }
+
+    /* Now load the program */
+    Status = ExLoadProgramOf(
+        LOADER_ELF64,
+        &RootProcess->Vas,
+        File.Data,
+        &Csrts
+    );
+
+    if (PT_ERROR(Status)) {
+        KeBugCheck(
+            BUGCHECK_MISC,
+            "unable to load csrts.sys\n"
+        );
+    }
+
+    Status = PsCreateThread(
+        RootProcess,
+        0,
+        Csrts.EntryPoint,
+        &RootThread
+    );
+
+    KeSchedEnqueue(&BootstrapCore.SchedQueue, RootThread);
 }
 
 /*