[Qemu-devel] [RFC v7 12/16] configure: Use slow-path for atomic only when the softmmu is enabled

[Alvise Rigo]

Use the new slow path for atomic instruction translation when the
softmmu is enabled.

At the moment only arm and aarch64 use the new LL/SC backend. It is
possible to disable such backed with --disable-arm-llsc-backend.

Suggested-by: Jani Kokkonen <address@hidden>
Suggested-by: Claudio Fontana <address@hidden>
Signed-off-by: Alvise Rigo <address@hidden>
---
 configure | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/configure b/configure
index 44ac9ab..915efcc 100755
--- a/configure
+++ b/configure
@@ -294,6 +294,7 @@ solaris="no"
 profiler="no"
 cocoa="no"
 softmmu="yes"
+arm_tcg_use_llsc="yes"
 linux_user="no"
 bsd_user="no"
 aix="no"
@@ -880,6 +881,10 @@ for opt do
   ;;
   --disable-debug-tcg) debug_tcg="no"
   ;;
+  --enable-arm-llsc-backend) arm_tcg_use_llsc="yes"
+  ;;
+  --disable-arm-llsc-backend) arm_tcg_use_llsc="no"
+  ;;
   --enable-debug)
       # Enable debugging options that aren't excessively noisy
       debug_tcg="yes"
@@ -4751,6 +4756,7 @@ echo "host CPU          $cpu"
 echo "host big endian   $bigendian"
 echo "target list       $target_list"
 echo "tcg debug enabled $debug_tcg"
+echo "arm use llsc backend" $arm_tcg_use_llsc
 echo "gprof enabled     $gprof"
 echo "sparse enabled    $sparse"
 echo "strip binaries    $strip_opt"
@@ -4806,6 +4812,7 @@ echo "Install blobs     $blobs"
 echo "KVM support       $kvm"
 echo "RDMA support      $rdma"
 echo "TCG interpreter   $tcg_interpreter"
+echo "use ld/st excl    $softmmu"
 echo "fdt support       $fdt"
 echo "preadv support    $preadv"
 echo "fdatasync         $fdatasync"
@@ -5863,6 +5870,13 @@ fi
 echo "LDFLAGS+=$ldflags" >> $config_target_mak
 echo "QEMU_CFLAGS+=$cflags" >> $config_target_mak
 
+# Use tcg LL/SC tcg backend for exclusive instruction is arm/aarch64
+# softmmus targets
+if test "$arm_tcg_use_llsc" = "yes" ; then
+  if test "$target" = "arm-softmmu" ; then
+    echo "CONFIG_ARM_USE_LDST_EXCL=y" >> $config_target_mak
+  fi
+fi
 done # for target in $targets
 
 if [ "$pixman" = "internal" ]; then
-- 
2.7.0