Make our own init script

The problem with the Stage 1 script is that is spawning another tee
process to forward the output to the console, but this is not required.
So let's only keep the memtool running by creating our own init script.

lagarto-ox.nix

@@ -80,6 +80,20 @@
       compressor = "gzip";
       kernelModules = [ ];
 
+      # Custom init script
+      extraFiles."/init2".source = pkgs.writeScript "init2" ''
+        #!${config.system.build.extraUtils}/bin/ash
+
+        set -x
+
+        export PATH=${config.system.build.extraUtils}/bin
+
+        memtool $((64 * 1024))
+
+        # Unlikely to reach this point
+        exec /init
+      '';
+
       # Add the csrtool to the initrd so we can change the
       # in-order/out-of-order, and memtool to stress the memory.
       extraUtilsCommands = ''
@@ -91,14 +105,7 @@
       # dead. Monitor from the host with:
       # while [ 1 ]; do xxd -s $((0x1bfff0000 - 0x60000000)) \
       #   -l 4 /dev/qdma34000-MM-1; sleep 0.2; done
-      preDeviceCommands =
+      preDeviceCommands = ''
-      # Run our memtool to hang the kernel here. Set the maximum block
-      # size to 64K.
-      ''
-        memtool $((64 * 1024))
-      ''
-      +
-      ''
         echo "Creating a heartbeat counter at 0x1bfff0000"
         sh -c 'hb=0; while [ 1 ]; do let hb=$hb+1; devmem 0x1bfff0000 32 $hb; done' &
       ''
@@ -272,7 +279,7 @@
       #   tp_printk                 write ftrace events to console
       #   trace_buf_size=1M         set ftrace buffer to 1M
       #
-      setenv bootargs "root=/dev/ram0 loglevel=7 debug rw earlycon=sbi console=hvc0 init=${init}"
+      setenv bootargs "root=/dev/ram0 loglevel=7 debug rw earlycon=sbi console=hvc0 rdinit=/init2 init=${init}"
 
       EOF