[PATCH tip/core/rcu 12/28] rcutorture: Abstract qemu-flavor identification

["Paul E. McKenney" <paulmck@linux.vnet.ibm.com>]

From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>

The task of working out which flavor of qemu to use gets more complex
as more types of CPUs are supported.  Adding Power makes three in addition
to 32-bit and 64-bit x86, so it is time to pull this out into a function.
This commit therefore creates an identify_qemu function and also adds
a --qemu-cmd command-line argument for the inevitable case where the
identify_qemu cannot figure it out.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
---
 .../testing/selftests/rcutorture/bin/functions.sh  | 27 ++++++++++++++++++++++
 .../selftests/rcutorture/bin/kvm-test-1-rcu.sh     |  9 +++-----
 tools/testing/selftests/rcutorture/bin/kvm.sh      |  6 +++++
 3 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/rcutorture/bin/functions.sh b/tools/testing/selftests/rcutorture/bin/functions.sh
index 8f912419ed7f..c974414ef7a5 100644
--- a/tools/testing/selftests/rcutorture/bin/functions.sh
+++ b/tools/testing/selftests/rcutorture/bin/functions.sh
@@ -51,3 +51,30 @@ configfrag_hotplug_cpu () {
 	fi
 	grep -q '^CONFIG_HOTPLUG_CPU=y$' "$1"
 }
+
+# identify_qemu builddir
+#
+# Returns our best guess as to which qemu command is appropriate for
+# the kernel at hand.  Override with the RCU_QEMU_CMD environment variable.
+identify_qemu () {
+	local u="`file "$1"`"
+	if test -n "$RCU_QEMU_CMD"
+	then
+		echo $RCU_QEMU_CMD
+	elif echo $u | grep -q x86-64
+	then
+		echo qemu-system-x86_64
+	elif echo $u | grep -q "Intel 80386"
+	then
+		echo qemu-system-i386
+	elif uname -a | grep -q ppc64
+	then
+		echo qemu-system-ppc64
+	else
+		echo Cannot figure out what qemu command to use! 1>&2
+		# Usually this will be one of /usr/bin/qemu-system-*
+		# Use RCU_QEMU_CMD environment variable or appropriate
+		# argument to top-level script.
+		exit 1
+	fi
+}
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-test-1-rcu.sh b/tools/testing/selftests/rcutorture/bin/kvm-test-1-rcu.sh
index 5526550a5d56..ddf3bd6eaf19 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-test-1-rcu.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-test-1-rcu.sh
@@ -109,12 +109,9 @@ boot_args=$6
 cd $KVM
 kstarttime=`awk 'BEGIN { print systime() }' < /dev/null`
 echo ' ---' `date`: Starting kernel
-if file linux-2.6/*.o | grep -q 64-bit
-then
-	QEMU=qemu-system-x86_64
-else
-	QEMU=qemu-system-i386
-fi
+
+# Determine the appropriate flavor of qemu command.
+QEMU="`identify_qemu $builddir/vmlinux.o`"
 
 # Generate -smp qemu argument.
 cpu_count=`configNR_CPUS.sh $config_template`
diff --git a/tools/testing/selftests/rcutorture/bin/kvm.sh b/tools/testing/selftests/rcutorture/bin/kvm.sh
index bf6d68e96e94..89164c245ca1 100644
--- a/tools/testing/selftests/rcutorture/bin/kvm.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm.sh
@@ -45,6 +45,7 @@ usage () {
 	echo "       --datestamp string"
 	echo "       --duration minutes"
 	echo "       --kversion vN.NN"
+	echo "       --qemu-cmd qemu-system-..."
 	echo "       --rcu-kvm absolute-pathname"
 	echo "       --results absolute-pathname"
 	echo "       --relbuilddir relative-pathname"
@@ -101,6 +102,11 @@ do
 		kversion=$2
 		shift
 		;;
+	--qemu-cmd)
+		checkarg --qemu-cmd "(qemu-system-...)" $# "$2" 'qemu-system-' '^--'
+		RCU_QEMU_CMD="$2"; export RCU_QEMU_CMD
+		shift
+		;;
 	--rcu-kvm)
 		checkarg --rcu-kvm "(absolute pathname)" "$#" "$2" '^/' error
 		KVM=$2; export KVM
-- 
1.8.1.5