break on the physical address of brkfunc

The kernel may panic early when paging is not yet configured. Breaking only on
the virtual address of brkfunc does not work in this case and leads to timeouts
during 'make grade'.

Signed-off-by: Junjie Mao <eternal.n08@gmail.com>

labcodes/lab6/tools/grade.sh

@@ -146,9 +146,13 @@ run_qemu() {
     if [ -n "$brkfun" ]; then
         # find the address of the kernel $brkfun function
         brkaddr=`$grep " $brkfun\$" $sym_table | $sed -e's/ .*$//g'`
+        brkaddr_phys=`echo $brkaddr | sed "s/^c0/00/g"`
         (
             echo "target remote localhost:$gdbport"
             echo "break *0x$brkaddr"
+            if [ "$brkaddr" != "$brkaddr_phys" ]; then
+                echo "break *0x$brkaddr_phys"
+            fi
             echo "continue"
         ) > $gdb_in
 
@@ -578,4 +582,3 @@ run_test -prog 'priority'      -check default_check             \
 
 ## print final-score
 show_final
-