From: Sinan Kaya <okaya@codeaurora.org>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Oliver <oohall@gmail.com>
Cc: "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
"open list:LINUX FOR POWERPC (32-BIT AND 64-BIT)"
<linuxppc-dev@lists.ozlabs.org>
Subject: Re: RFC on writel and writel_relaxed
Date: Thu, 22 Mar 2018 12:51:15 -0500 [thread overview]
Message-ID: <5ccdb208-4664-0a7f-df5d-2e12cbe4c239@codeaurora.org> (raw)
In-Reply-To: <1521726722.16434.312.camel@kernel.crashing.org>
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.
WARNING: multiple messages have this Message-ID (diff)
From: Sinan Kaya <okaya@codeaurora.org>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Oliver <oohall@gmail.com>
Cc: "open list:LINUX FOR POWERPC (32-BIT AND 64-BIT)"
<linuxppc-dev@lists.ozlabs.org>,
"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>
Subject: Re: RFC on writel and writel_relaxed
Date: Thu, 22 Mar 2018 12:51:15 -0500 [thread overview]
Message-ID: <5ccdb208-4664-0a7f-df5d-2e12cbe4c239@codeaurora.org> (raw)
In-Reply-To: <1521726722.16434.312.camel@kernel.crashing.org>
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.
next prev parent reply other threads:[~2018-03-22 17:51 UTC|newest]
Thread overview: 216+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-21 3:07 RFC on writel and writel_relaxed Sinan Kaya
2018-03-21 3:40 ` Oliver
2018-03-21 3:40 ` Oliver
2018-03-21 13:53 ` Sinan Kaya
2018-03-21 13:53 ` Sinan Kaya
2018-03-21 13:58 ` Sinan Kaya
2018-03-21 13:58 ` Sinan Kaya
2018-03-26 13:43 ` Arnd Bergmann
2018-03-26 13:43 ` Arnd Bergmann
2018-03-26 16:00 ` Sinan Kaya
2018-03-26 16:00 ` Sinan Kaya
2018-03-21 14:35 ` David Laight
2018-03-21 14:35 ` David Laight
2018-03-21 15:04 ` Sinan Kaya
2018-03-22 5:24 ` Oliver
2018-03-22 8:20 ` Gabriel Paubert
2018-03-22 8:20 ` Gabriel Paubert
2018-03-22 9:25 ` Oliver
2018-03-22 9:25 ` Oliver
2018-03-22 11:25 ` Gabriel Paubert
2018-03-22 11:25 ` Gabriel Paubert
2018-03-22 10:37 ` David Laight
2018-03-22 10:37 ` David Laight
2018-03-22 4:24 ` Benjamin Herrenschmidt
2018-03-22 4:24 ` Benjamin Herrenschmidt
2018-03-22 10:15 ` Oliver
2018-03-22 10:15 ` Oliver
2018-03-22 13:52 ` Benjamin Herrenschmidt
2018-03-22 13:52 ` Benjamin Herrenschmidt
2018-03-22 17:51 ` Sinan Kaya [this message]
2018-03-22 17:51 ` Sinan Kaya
2018-03-23 0:16 ` Benjamin Herrenschmidt
2018-03-23 0:16 ` Benjamin Herrenschmidt
2018-03-23 13:42 ` Sinan Kaya
2018-03-23 13:42 ` Sinan Kaya
2018-03-24 1:22 ` Benjamin Herrenschmidt
2018-03-24 1:22 ` Benjamin Herrenschmidt
2018-03-24 15:06 ` Sinan Kaya
2018-03-24 15:06 ` Sinan Kaya
2018-03-26 11:44 ` Will Deacon
2018-03-26 11:44 ` Will Deacon
2018-03-26 12:11 ` okaya
2018-03-26 12:11 ` okaya
2018-03-26 12:42 ` Sinan Kaya
2018-03-26 12:42 ` Sinan Kaya
2018-03-23 16:35 ` Jason Gunthorpe
2018-03-23 16:35 ` Jason Gunthorpe
2018-03-24 1:23 ` Benjamin Herrenschmidt
2018-03-24 1:23 ` Benjamin Herrenschmidt
2018-03-26 11:08 ` David Laight
2018-03-26 11:08 ` David Laight
2018-03-26 16:54 ` Jason Gunthorpe
2018-03-26 16:54 ` Jason Gunthorpe
2018-03-26 19:44 ` Arnd Bergmann
2018-03-26 19:44 ` Arnd Bergmann
2018-03-26 20:25 ` Jason Gunthorpe
2018-03-26 20:25 ` Jason Gunthorpe
2018-03-26 20:43 ` Arnd Bergmann
2018-03-26 20:43 ` Arnd Bergmann
2018-03-26 21:09 ` Jason Gunthorpe
2018-03-26 21:09 ` Jason Gunthorpe
2018-03-26 21:30 ` Arnd Bergmann
2018-03-26 21:30 ` Arnd Bergmann
2018-03-26 21:46 ` Sinan Kaya
2018-03-26 21:46 ` Sinan Kaya
2018-03-26 22:01 ` Benjamin Herrenschmidt
2018-03-26 22:01 ` Benjamin Herrenschmidt
2018-03-26 22:08 ` Sinan Kaya
2018-03-26 22:08 ` Sinan Kaya
2018-03-26 22:28 ` Benjamin Herrenschmidt
2018-03-26 22:28 ` Benjamin Herrenschmidt
2018-03-26 22:27 ` Jason Gunthorpe
2018-03-26 22:27 ` Jason Gunthorpe
2018-03-26 22:36 ` Benjamin Herrenschmidt
2018-03-26 22:36 ` Benjamin Herrenschmidt
2018-03-26 22:42 ` Benjamin Herrenschmidt
2018-03-26 22:42 ` Benjamin Herrenschmidt
2018-03-26 22:50 ` Jason Gunthorpe
2018-03-26 22:50 ` Jason Gunthorpe
2018-03-26 23:59 ` Benjamin Herrenschmidt
2018-03-26 23:59 ` Benjamin Herrenschmidt
2018-03-27 1:39 ` Jason Gunthorpe
2018-03-27 1:39 ` Jason Gunthorpe
2018-03-27 7:56 ` Arnd Bergmann
2018-03-27 7:56 ` Arnd Bergmann
2018-03-27 8:56 ` Benjamin Herrenschmidt
2018-03-27 8:56 ` Benjamin Herrenschmidt
2018-03-27 9:44 ` Arnd Bergmann
2018-03-27 9:44 ` Arnd Bergmann
2018-03-27 10:00 ` Will Deacon
2018-03-27 10:00 ` Will Deacon
2018-03-27 11:23 ` Benjamin Herrenschmidt
2018-03-27 11:23 ` Benjamin Herrenschmidt
2018-03-27 12:22 ` okaya
2018-03-27 12:22 ` okaya
2018-03-27 14:12 ` Jason Gunthorpe
2018-03-27 14:12 ` Jason Gunthorpe
2018-03-27 21:27 ` Benjamin Herrenschmidt
2018-03-27 21:27 ` Benjamin Herrenschmidt
2018-03-27 9:57 ` Will Deacon
2018-03-27 9:57 ` Will Deacon
2018-03-27 10:05 ` Arnd Bergmann
2018-03-27 10:05 ` Arnd Bergmann
2018-03-27 10:09 ` Will Deacon
2018-03-27 10:09 ` Will Deacon
2018-03-27 10:53 ` Arnd Bergmann
2018-03-27 10:53 ` Arnd Bergmann
2018-03-27 11:02 ` Will Deacon
2018-03-27 11:02 ` Will Deacon
2018-03-27 11:05 ` Arnd Bergmann
2018-03-27 11:05 ` Arnd Bergmann
2018-03-27 11:25 ` Benjamin Herrenschmidt
2018-03-27 11:25 ` Benjamin Herrenschmidt
2018-03-27 13:20 ` David Laight
2018-03-27 13:20 ` David Laight
2018-03-27 13:46 ` Sinan Kaya
2018-03-27 13:46 ` Sinan Kaya
2018-03-27 14:36 ` Will Deacon
2018-03-27 14:36 ` Will Deacon
2018-03-27 21:29 ` Benjamin Herrenschmidt
2018-03-27 21:29 ` Benjamin Herrenschmidt
2018-03-28 8:53 ` Will Deacon
2018-03-28 8:53 ` Will Deacon
2018-03-28 9:00 ` David Laight
2018-03-28 9:00 ` David Laight
2018-03-28 9:09 ` Will Deacon
2018-03-28 9:09 ` Will Deacon
2018-03-28 9:56 ` Benjamin Herrenschmidt
2018-03-28 9:56 ` Benjamin Herrenschmidt
2018-03-28 9:50 ` Benjamin Herrenschmidt
2018-03-28 9:50 ` Benjamin Herrenschmidt
2018-03-28 9:55 ` Arnd Bergmann
2018-03-28 9:55 ` Arnd Bergmann
2018-03-28 10:01 ` Benjamin Herrenschmidt
2018-03-28 10:01 ` Benjamin Herrenschmidt
2018-03-28 10:13 ` Will Deacon
2018-03-28 10:13 ` Will Deacon
2018-03-28 16:57 ` Jason Gunthorpe
2018-03-28 16:57 ` Jason Gunthorpe
2018-03-29 9:19 ` Will Deacon
2018-03-29 9:19 ` Will Deacon
2018-03-29 14:45 ` Jason Gunthorpe
2018-03-29 14:45 ` Jason Gunthorpe
2018-03-29 14:58 ` David Laight
2018-03-29 14:58 ` David Laight
2018-03-29 16:40 ` Jason Gunthorpe
2018-03-29 16:40 ` Jason Gunthorpe
2018-03-27 21:24 ` Benjamin Herrenschmidt
2018-03-27 21:24 ` Benjamin Herrenschmidt
2018-03-27 11:21 ` Benjamin Herrenschmidt
2018-03-27 11:21 ` Benjamin Herrenschmidt
2018-03-27 9:42 ` Will Deacon
2018-03-27 9:42 ` Will Deacon
2018-03-27 11:20 ` Benjamin Herrenschmidt
2018-03-27 11:20 ` Benjamin Herrenschmidt
2018-03-27 11:24 ` Will Deacon
2018-03-27 11:24 ` Will Deacon
2018-03-27 14:24 ` Jason Gunthorpe
2018-03-27 14:24 ` Jason Gunthorpe
2018-03-27 14:16 ` Jason Gunthorpe
2018-03-27 14:16 ` Jason Gunthorpe
2018-03-26 22:00 ` Benjamin Herrenschmidt
2018-03-26 22:00 ` Benjamin Herrenschmidt
2018-03-27 14:46 ` Sinan Kaya
2018-03-27 15:01 ` Jose Abreu
2018-03-27 15:10 ` Will Deacon
2018-03-27 18:54 ` Alexander Duyck
2018-03-27 19:54 ` Arnd Bergmann
2018-03-27 19:54 ` Arnd Bergmann
2018-03-27 20:46 ` Arnd Bergmann
2018-03-27 20:46 ` Arnd Bergmann
2018-03-27 21:33 ` Benjamin Herrenschmidt
2018-03-28 0:39 ` Linus Torvalds
2018-03-28 1:03 ` Benjamin Herrenschmidt
2018-03-28 2:51 ` Linus Torvalds
2018-03-28 3:24 ` Sinan Kaya
2018-03-28 4:41 ` Benjamin Herrenschmidt
2018-03-28 6:14 ` Linus Torvalds
2018-03-28 11:41 ` okaya
2018-03-28 15:13 ` Benjamin Herrenschmidt
2018-03-28 15:55 ` David Miller
2018-03-28 16:23 ` Nicholas Piggin
2018-03-28 21:31 ` Benjamin Herrenschmidt
2018-03-28 22:09 ` Nicholas Piggin
2018-03-29 9:20 ` Will Deacon
2018-03-29 13:56 ` Sinan Kaya
2018-03-29 14:04 ` David Miller
2018-03-29 16:29 ` Arnd Bergmann
2018-03-29 16:59 ` Sinan Kaya
2018-03-30 1:40 ` Benjamin Herrenschmidt
2018-04-02 13:01 ` Sinan Kaya
2018-03-28 4:33 ` Benjamin Herrenschmidt
2018-03-28 6:26 ` Linus Torvalds
2018-03-28 6:42 ` Benjamin Herrenschmidt
2018-03-28 6:53 ` Linus Torvalds
2018-03-28 6:53 ` Linus Torvalds
2018-03-28 6:53 ` Linus Torvalds
2018-03-28 6:56 ` Benjamin Herrenschmidt
2018-03-28 7:11 ` Arnd Bergmann
2018-03-28 7:42 ` Benjamin Herrenschmidt
2018-03-28 9:07 ` Will Deacon
2018-03-28 9:56 ` Benjamin Herrenschmidt
2018-03-28 10:13 ` Aw: " Lino Sanfilippo
2018-03-28 10:20 ` Benjamin Herrenschmidt
2018-03-28 11:30 ` David Laight
2018-03-28 11:30 ` David Laight
2018-03-28 15:12 ` Benjamin Herrenschmidt
2018-03-28 16:16 ` David Laight
2018-03-28 16:16 ` David Laight
2018-03-28 1:21 ` Benjamin Herrenschmidt
2018-03-27 21:35 ` Benjamin Herrenschmidt
2018-03-26 21:26 ` Benjamin Herrenschmidt
2018-03-26 21:26 ` Benjamin Herrenschmidt
2018-03-27 21:54 Alexander Duyck
2018-03-27 22:35 ` Sinan Kaya
2018-03-27 23:43 ` Benjamin Herrenschmidt
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