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Subject: Re: RFC on writel and writel_relaxed
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
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From: Sinan Kaya <okaya@codeaurora.org>
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Date: Thu, 22 Mar 2018 12:51:15 -0500
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On 3/22/2018 8:52 AM, Benjamin Herrenschmidt wrote:
>>> No, it's not sufficient.
> Just to clarify ... barrier() is just a compiler barrier, it means the
> compiler will generate things in the order they are written. This isn't
> sufficient on archs with an OO memory model, where an actual memory
> barrier instruction needs to be emited.

Surprisingly, ARM64 GCC compiler generates a write barrier as
opposed to preventing code reordering.

I was curious if this is an ARM only thing or not. 

-- 
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.