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Re: [PATCH 3/7] asm-generic/io.h: make ioread64 and iowrite64 universally available

From Logan Gunthorpe <logang@deltatee.com>
Newsgroups linux.kernel
Subject Re: [PATCH 3/7] asm-generic/io.h: make ioread64 and iowrite64 universally available
Date 2017-06-22 22:30 +0200
Message-ID <tVgTL-15s-5@gated-at.bofh.it> (permalink)
References <tVdsS-7hT-17@gated-at.bofh.it> <tVdsT-7hT-33@gated-at.bofh.it> <tVgK5-10A-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On 6/22/2017 2:14 PM, Alan Cox wrote:
> If a platform doesn't support 64bit I/O operations from the CPU then you
> either need to use some kind of platform/architecture specific interface
> if present or accept you don't have one.

Yes, I understand that.

The thing is that every user that's currently using it right now is 
patching in their own version that splits it on non-64bit systems.

> It's not safe to split it. Possibly for some use cases you could add an
> ioread64_maysplit()

I'm open to doing something like that.

> What btw is the actual ARM compiler warning ? Is the compiler also trying
> to tell you it's a bad idea ?

It's just the compiler noting that you are mixing volatile and 
non-volatile pointers. Strangely some io{read|write}XX use volatile but 
most do not. But it's nothing crazy.

Logan

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Thread

[PATCH 3/7] asm-generic/io.h: make ioread64 and iowrite64 universally available Logan Gunthorpe <logang@deltatee.com> - 2017-06-22 18:50 +0200
  Re: [PATCH 3/7] asm-generic/io.h: make ioread64 and iowrite64  universally available Alan Cox <gnomes@lxorguk.ukuu.org.uk> - 2017-06-22 22:20 +0200
    Re: [PATCH 3/7] asm-generic/io.h: make ioread64 and iowrite64  universally available Logan Gunthorpe <logang@deltatee.com> - 2017-06-22 22:30 +0200
      Re: [PATCH 3/7] asm-generic/io.h: make ioread64 and iowrite64  universally available Alan Cox <gnomes@lxorguk.ukuu.org.uk> - 2017-06-22 22:40 +0200
        Re: [PATCH 3/7] asm-generic/io.h: make ioread64 and iowrite64  universally available Logan Gunthorpe <logang@deltatee.com> - 2017-06-22 22:40 +0200

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