Aurelien Jarno <aurel...@aurel32.net> writes: > On 2015-08-09 10:51, Alex Bennée wrote: >> >> Aurelien Jarno <aurel...@aurel32.net> writes: >> >> > On 2015-08-09 09:11, Alex Bennée wrote: >> >> >> >> Aurelien Jarno <aurel...@aurel32.net> writes: >> >> >> >> > On 2015-08-07 19:03, Alvise Rigo wrote: >> >> >> Introduce the new --enable-tcg-ldst-excl configure option to enable the >> >> >> LL/SC operations only for those backends that support them. >> >> >> >> >> >> 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 | 21 +++++++++++++++++++++ >> >> >> 1 file changed, 21 insertions(+) >> >> > >> >> > We have seen that for this kind of patch, it's better to add support in >> >> > all backends, otherwise it takes ages to get all the backends converted. >> >> > I think you should involve the backend maintainers. I can try to provide >> >> > the corresponding patches for mips and ia64. >> >> >> >> We discussed this on the last MTTCG call and agree. However we will need >> >> help from the other TCG maintainers for the backends. The changes should >> >> be fairly mechanical though. >> >> >> >> However in the spirit of keeping trees building in the meantime should >> >> we change this from a configure option to just a static option for each >> >> given backend as it is converted? >> > >> > I am not even sure we need a static option. I guess providing we are >> > doing that early enough in the 2.5 cycle, we can just add the new ops >> > and start using them. Of course we should put the backends maintainers >> > in the loop so they can fix that quickly and don't get a surprise weeks >> > afters. >> > >> > That said, please see my other email, I am not sure we actually need to >> > modify backends, I think we can implement these new "ops" through >> > tcg-runtime. >> >> We still need to ensure "normal" ld/st operations trip the exclusive bit >> though. > > Isn't that taken care of by the TLB_EXCL flag, causing pages in > exclusive mode to always go through the slow path? Then we should not > need to modify the backends as they already check for non zero bits in > this area.
Ahh I see. Yes of course that sounds like a good idea. -- Alex Bennée
