Messages in this thread | | | Date | Wed, 27 Sep 2017 11:10:19 +0100 | From | Mark Rutland <> | Subject | Re: [PATCH] percpu: make this_cpu_generic_read() atomic w.r.t. interrupts |
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On Wed, Sep 27, 2017 at 11:01:13AM +0200, Thomas Gleixner wrote: > The default for 32bit architectures is that they CANNOT do atomic > fetch/write of 8 bytes.
Indeed.
In addition, even the native word size accesses weren't guaranteed to be atomic, as we hadn't used the appropriate accessors to prevent the compiler from messing with things behind our backs.
> So instead of forcing that to be implemented in every affected > architecture this wants to be addressed in generic code and those few > 32bit architectures which can do atomic double word fetch/write > implement the magic functions to do so.
I've done this in v2 [1], which Tejun has queued [2] as a fix for v4.14.
Thanks, Mark.
[1] https://lkml.kernel.org/r/1506426112-19826-1-git-send-email-mark.rutland@arm.com [2] https://lkml.kernel.org/r/20170926144118.GA70381@devbig577.frc2.facebook.com
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