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| -rw-r--r-- | configs/boot/hack_back_ckpt.rcS | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/configs/boot/hack_back_ckpt.rcS b/configs/boot/hack_back_ckpt.rcS new file mode 100644 index 000000000..4c38a4d32 --- /dev/null +++ b/configs/boot/hack_back_ckpt.rcS @@ -0,0 +1,62 @@ +#!/bin/sh + +# +# This is a tricky script to understand. When run in M5, it creates +# a checkpoint after Linux boot up, but before any benchmarks have +# been run. By playing around with environment variables, we can +# detect whether the checkpoint has been taken. +# - If the checkpoint hasn't been taken, the script allows M5 to checkpoint the system, +# re-read this script into a new tmp file, and re-run it. On the +# second execution of this script (checkpoint has been taken), the +# environment variable is already set, so the script will exit the +# simulation +# - When we restore the simulation from a checkpoint, we can +# specify a new script for M5 to execute in the full-system simulation, +# and it will be executed as if a checkpoint had just been taken. +# +# Author: +# Joel Hestness, hestness@cs.utexas.edu +# while at AMD Research and Advanced Development Lab +# Date: +# 10/5/2010 +# + +# Test if the RUNSCRIPT_VAR environment variable is already set +if [ "${RUNSCRIPT_VAR+set}" != set ] +then + # Signal our future self that it's safe to continue + export RUNSCRIPT_VAR=1 +else + # We've already executed once, so we should exit + /sbin/m5 exit +fi + +# Checkpoint the first execution +echo "Checkpointing simulation..." +/sbin/m5 checkpoint + +# Test if we previously okayed ourselves to run this script +if [ "$RUNSCRIPT_VAR" -eq 1 ] +then + + # Signal our future self not to recurse infinitely + export RUNSCRIPT_VAR=2 + + # Read the script for the checkpoint restored execution + echo "Loading new script..." + /sbin/m5 readfile > /tmp/runscript + chmod 755 /tmp/runscript + + # Execute the new runscript + if [ -s /tmp/runscript ] + then + exec /tmp/runscript + else + echo "Script not specified. Dropping into shell..." + /bin/bash + fi + +fi + +echo "Fell through script. Exiting..." +/sbin/m5 exit |