Messages in this thread | | | Date | Tue, 10 Sep 2019 15:21:21 +0100 | From | Andrew Murray <> | Subject | Re: [PATCH] arm64: fix unreachable code issue with cmpxchg |
| |
On Tue, Sep 10, 2019 at 08:46:07AM +0100, Will Deacon wrote: > On Mon, Sep 09, 2019 at 10:21:35PM +0200, Arnd Bergmann wrote: > > On arm64 build with clang, sometimes the __cmpxchg_mb is not inlined > > when CONFIG_OPTIMIZE_INLINING is set. > > Hmm. Given that CONFIG_OPTIMIZE_INLINING has also been shown to break > assignment of local 'register' variables on GCC, perhaps we should just > disable that option for arm64 (at least) since we don't have any toolchains > that seem to like it very much! I'd certainly prefer that over playing > whack-a-mole with __always_inline.
I assume we're referring to stuff such as the following?
https://www.spinics.net/lists/arm-kernel/msg730329.html
Are these breakages limited to the out-of-line hacks made for LL/SC atomics, or were there other breakages elsewhere?
Now that the out-of-line hacks have gone, I wonder if this is actually still a problem anymore. In any case isn't the right thing to do there to add the __always_inline to functions that use the register keyword in a function currently annotated inline?
I'm happy to look into this if there is likely to be some benefit in turning on CONFIG_OPTIMIZE_INLINING.
Thanks,
Andrew Murray
> > Will
| |