On Thu, Feb 18, 2016 at 5:40 PM, Alex Bennée <alex.ben...@linaro.org> wrote: > > Alvise Rigo <a.r...@virtualopensystems.com> writes: > >> 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. > > Do we want to disable the backend once it is merged? Does it serve a > purpose other than to confuse the user?
I added this option in order to have a quick way to compile a binary with an without backend, it has been useful in the development process. Now it's probably time to drop it. Thank you, alvise > >> >> Suggested-by: Jani Kokkonen <jani.kokko...@huawei.com> >> Suggested-by: Claudio Fontana <claudio.font...@huawei.com> >> Signed-off-by: Alvise Rigo <a.r...@virtualopensystems.com> >> --- >> 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" > > I think we can drop everything above here. > >> 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" >> $config_target_mak >> + fi >> +fi > > This isn't going to be just ARM specific and it will be progressively > turned on for other arches. So perhaps with the CONFIG_SOFTMMU section: > > if test "$target_softmmu" = "yes" ; then > echo "CONFIG_SOFTMMU=y" >> $config_target_mak > > # Use SoftMMU LL/SC primitives? > case "$target_name" in > arm | aarch64) > echo "CONFIG_USE_LDST_EXCL=y" >> $config_target_mak > ;; > esac > fi > > >> done # for target in $targets >> >> if [ "$pixman" = "internal" ]; then > > > -- > Alex Bennée