Messages in this thread | | | Date | Thu, 20 Nov 2014 12:30:30 -0800 | Subject | Re: compiler bug gcc4.6/4.7 with ACCESS_ONCE and workarounds | From | Linus Torvalds <> |
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On Thu, Nov 20, 2014 at 3:39 AM, Christian Borntraeger <borntraeger@de.ibm.com> wrote: > > So It looks like we could make a change to ACCESS_ONCE. Would something like > > CONFIG_ARCH_SCALAR_ACCESS_ONCE be a good start?
No, if it's just a handful of places to be fixed, let's not add config options for broken cases.
> This would boil down to > Patch1: Provide stricter ACCESS_ONCE if CONFIG_ARCH_SCALAR_ACCESS_ONCE is set + docu update + comments > Patch2: Change mm/* to barriers > Patch3: Change x86 locks > Patch4: Change x86 gup > Patch4: Enable CONFIG_ARCH_SCALAR_ACCESS_ONCE for s390x and x86
Just do patches 2-4 first, and then patch 1 unconditionally.
Obviously you'd need to spread the word on linux-arch to see how bad it is for other cases, but if other architectures are at all like x86 and s390, and just require a few trivial patches, let's not make this some config option.
Linus
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