From: Andrew Murray <firstname.lastname@example.org>
To: Will Deacon <email@example.com>
Cc: Arnd Bergmann <firstname.lastname@example.org>,
Catalin Marinas <email@example.com>,
Mark Rutland <firstname.lastname@example.org>,
Subject: Re: [PATCH] arm64: fix unreachable code issue with cmpxchg
Date: Tue, 10 Sep 2019 15:21:21 +0100 [thread overview]
Message-ID: <20190910142120.GM9720@e119886-lin.cambridge.arm.com> (raw)
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?
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.
next prev parent reply other threads:[~2019-09-10 14:21 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-09 20:21 [PATCH] arm64: fix unreachable code issue with cmpxchg Arnd Bergmann
2019-09-09 21:06 ` Nick Desaulniers
2019-09-09 21:35 ` Nick Desaulniers
2019-09-10 3:42 ` Nathan Chancellor
2019-09-10 7:46 ` Will Deacon
2019-09-10 8:04 ` Arnd Bergmann
2019-09-10 13:24 ` Will Deacon
2019-09-10 13:43 ` Arnd Bergmann
2019-09-10 14:21 ` Andrew Murray [this message]
2019-09-10 9:23 ` Andrew Murray
2019-09-10 9:38 ` Arnd Bergmann
2019-09-10 10:17 ` Masahiro Yamada
2019-09-10 10:24 ` Andrew Murray
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