GEM5 gdb debug

Improve GEM5 documentation in general.

Fix documentation for x86 kernel module debugging example, fop_write had been made static,
and use timer.ko instead of fops which is more reliable and fun.

rungdb

@@ -4,8 +4,9 @@ set -e
 
 arch='x86_64'
 bdfore=''
+gem5=false
 kgdb=false
-while getopts A:a:b:k OPT; do
+while getopts A:a:b:gk OPT; do
   case "$OPT" in
     a)
       arch="$OPTARG"
@@ -16,6 +17,9 @@ while getopts A:a:b:k OPT; do
     b)
       before="$OPTARG"
       ;;
+    g)
+      gem5=true
+      ;;
     k)
       kgdb=true
       ;;
@@ -28,8 +32,15 @@ if [ "$#" -gt 0 ]; then
 else
   brk=''
 fi
+if "$gem5"; then
+  arch_dir="${arch}-gem5"
+  port=7000
+else
+  arch_dir="$arch"
+  port=1234
+fi
 
-buildroot_out_dir="$(pwd)/buildroot/output.${arch}~"
+buildroot_out_dir="$(pwd)/buildroot/output.${arch_dir}~"
 gdb="${buildroot_out_dir}/host/usr/bin/${arch}-linux-gdb $before"
 cd "${buildroot_out_dir}/build/linux-custom/"
 if "$kgdb"; then
@@ -37,7 +48,7 @@ if "$kgdb"; then
       -q \
       -ex 'add-auto-load-safe-path $(pwd)' \
       -ex 'file vmlinux' \
-      -ex 'target remote localhost:1234'
+      -ex 'target remote localhost:$port'
     "
 else
   case "$arch" in
@@ -47,12 +58,12 @@ else
 -ex 'add-auto-load-safe-path $(pwd)' \
 -ex 'file vmlinux' \
 -ex 'set arch i386:x86-64:intel' \
--ex 'target remote localhost:1234' \
+-ex 'target remote localhost:$port' \
 $brk \
 -ex 'continue' \
 -ex 'disconnect' \
 -ex 'set arch i386:x86-64' \
--ex 'target remote localhost:1234' \
+-ex 'target remote localhost:$port' \
 -ex 'lx-symbols ../kernel_module-1.0/' \
 "
     ;;
@@ -61,7 +72,7 @@ $brk \
 -q \
 -ex 'add-auto-load-safe-path $(pwd)' \
 -ex 'file vmlinux' \
--ex 'target remote localhost:1234' \
+-ex 'target remote localhost:$port' \
 -ex 'lx-symbols ../kernel_module-1.0/' \
 $brk \
 "