resources: Move to gem5 bridge devices in x86 disk files

Author: nkrim

src/x86-ubuntu/files/after_boot.sh

@@ -14,7 +14,7 @@
 
 # gem5-bridge exit signifying that after_boot.sh is running
 printf "In after_boot.sh...\n"
-gem5-bridge exit # TODO: Make this a specialized event.
+echo 0 > /dev/gem5/exit # TODO: Make this a specialized event.
 
 # Read /proc/cmdline and parse options
 
@@ -28,19 +28,19 @@ fi
 printf "Interactive mode: $interactive\n"
 
 if [[ $interactive == true ]]; then
-    printf "Interactive mode enabled, dropping to shell."
+    printf "Interactive mode enabled, dropping to shell.\n"
     /bin/bash
 else
     # Try to read the file from the host when running with gem5
     if ! [ -z $IGNORE_M5 ]; then
         printf "Starting gem5 init... trying to read run script file via readfile.\n"
-        if ! gem5-bridge readfile > /tmp/script; then
+        if ! cat /dev/gem5/readfile > /tmp/script; then
             printf "Failed to run gem5-bridge readfile, exiting!\n"
             rm -f /tmp/script
             # If we can't read the script exit the simulation. If we cannot exit the
             # simulation, this probably means that we are running in QEMU. So, ignore
             # future calls to gem5-bridge.
-            if ! gem5-bridge exit; then
+            if ! echo 0 > /dev/gem5/exit; then
                 # Useful for booting the disk image in (e.g.,) qemu for debugging
                 printf "gem5-bridge exit failed, dropping to shell.\n"
                 IGNORE_M5=1 /bin/bash
@@ -51,7 +51,7 @@ else
             /tmp/script
             printf "Done running script from gem5-bridge, exiting.\n"
             rm -f /tmp/script
-            gem5-bridge exit
+            echo 0 > /dev/gem5/exit
         fi
     fi
 fi

src/x86-ubuntu/files/exit.sh

@@ -3,4 +3,4 @@
 # Copyright (c) 2020 The Regents of the University of California.
 # SPDX-License-Identifier: BSD 3-Clause
 
-m5 exit
+echo 0 > /dev/gem5/exit

src/x86-ubuntu/files/gem5_init.sh

@@ -22,7 +22,7 @@ modprobe gem5_bridge || insmod /lib/modules/$(uname -r)/gem5/gem5_bridge.ko
 # This will cause the simulation to exit. Note that this will
 # cause qemu to fail.
 printf "Kernel booted, In gem5 init...\n"
-gem5-bridge exit # TODO: Make this a specialized event.
+echo 0 > /dev/gem5/exit # TODO: Make this a specialized event.
 
 if [[ $cmdline == *"no_systemd"* ]]; then
     no_systemd=true