From: Sinan Kaya <okaya@codeaurora.org>
To: Will Deacon <will.deacon@arm.com>
Cc: David Woodhouse <dwmw2@infradead.org>,
linux-pci@vger.kernel.org, linux-arch@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 17/17] arm64: Do not expose PCI mmap through procfs
Date: Wed, 22 Mar 2017 11:40:52 -0400 [thread overview]
Message-ID: <517f4cc1-df3b-553b-59bf-f60ddd7c32d8@codeaurora.org> (raw)
In-Reply-To: <20170322141820.GI8026@arm.com>
On 3/22/2017 10:18 AM, Will Deacon wrote:
> On Wed, Mar 22, 2017 at 10:15:04AM -0400, Sinan Kaya wrote:
>> On 3/22/2017 10:04 AM, David Woodhouse wrote:
>>> On Wed, 2017-03-22 at 09:54 -0400, Sinan Kaya wrote:
>>>> On 3/22/2017 9:25 AM, David Woodhouse wrote:
>>>>>
>>>>>
>>>>> +#ifdef __aarch64__
>>>>> +/* ARM64 wants to be special and not expose this through /proc
>>>>> like everyone else */
>>>>> +#undef HAVE_PCI_MMAP
>>>>> +#endif
>>>>> +
>>>> Where is this ARM64 special requirement coming from?
>>>
>>> The idea is that as a new platform, ARM64 shouldn't need to implement
>>> legacy userspace interfaces.
>>>
>>> http://lists.infradead.org/pipermail/linux-arm-kernel/2016-April/422571.html
>>>
>>
>> Aren't we breaking an ABI for userspace? I know DPDK relies on this feature.
>
> It relies on the /proc interface? That's the first I've ever heard of that
> -- everybody so far has only been interested in the sysfs stuff.
>
> Nothing's more broken than before, because we've never supported the /proc
> interface, but if existing arm64 code out there is failing because of that
> then I'm of course open to supporting it. I'm just surprised that nobody
> else has come up with that before, since DPDK is in common use.
>
> Can you point me at the specific code, please?
I'm correcting myself. I had to go back my memory from last year.
DPDK requires HAVE_PCI_MMAP to be set. We have been carrying
some old maillist patch around for DPDK customers internally.
When HAVE_PCI_MMAP is set, resource files are created in sysfs and procfs.
DPDK is using the files in sysfs directory not procfs directory.
Having HAVE_PCI_MMAP defined is the DPDK requirement.
>
> Will
>
--
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:[~2017-03-22 15:41 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-22 13:25 [PATCH 00/17] PCI resource mmap cleanup David Woodhouse
2017-03-22 13:25 ` [PATCH 01/17] pci: Fix pci_mmap_fits() for HAVE_PCI_RESOURCE_TO_USER platforms David Woodhouse
2017-03-22 13:25 ` [PATCH 02/17] pci: Fix another sanity check bug in /proc/pci mmap David Woodhouse
2017-03-22 13:25 ` [PATCH 03/17] pci: Only allow WC mmap on prefetchable resources David Woodhouse
2017-03-24 16:05 ` Arnd Bergmann
2017-03-24 17:04 ` David Woodhouse
2017-03-22 13:25 ` [PATCH 04/17] pci: Add arch_can_pci_mmap_wc() macro David Woodhouse
2017-04-04 21:36 ` Bjorn Helgaas
2017-04-05 7:22 ` David Woodhouse
2017-03-22 13:25 ` [PATCH 05/17] pci: Move multiple declarations of pci_mmap_page_range() to <linux/pci.h> David Woodhouse
2017-03-22 13:25 ` [PATCH 06/17] pci: Add HAVE_PCI_MMAP_IO to architectures which can mmap() I/O space David Woodhouse
2017-03-22 13:25 ` [PATCH 07/17] pci: Use BAR index in sysfs attr->private instead of resource pointer David Woodhouse
2017-03-22 13:25 ` [PATCH 08/17] pci: Add BAR index argument to pci_mmap_page_range() David Woodhouse
2017-03-22 13:25 ` [PATCH 09/17] pci: Add pci_mmap_resource_range() and use it for ARM64 David Woodhouse
2017-03-22 13:25 ` [PATCH 10/17] arm: Use generic pci_mmap_resource_range() David Woodhouse
2017-03-22 13:25 ` [PATCH 11/17] cris: " David Woodhouse
2017-03-22 13:33 ` Jesper Nilsson
2017-03-22 13:25 ` [PATCH 12/17] mips: " David Woodhouse
2017-03-22 13:25 ` [PATCH 13/17] mn10300: " David Woodhouse
2017-03-22 13:25 ` [PATCH 14/17] parisc: " David Woodhouse
2017-03-22 13:25 ` [PATCH 15/17] sh: " David Woodhouse
2017-03-22 13:25 ` [PATCH 16/17] unicore: " David Woodhouse
2017-03-22 13:25 ` [PATCH 17/17] arm64: Do not expose PCI mmap through procfs David Woodhouse
2017-03-22 13:54 ` Sinan Kaya
2017-03-22 14:04 ` David Woodhouse
2017-03-22 14:15 ` Sinan Kaya
2017-03-22 14:18 ` Will Deacon
2017-03-22 15:40 ` Sinan Kaya [this message]
2017-03-24 16:13 ` Arnd Bergmann
2017-03-24 16:16 ` Arnd Bergmann
2017-03-24 16:23 ` David Woodhouse
2017-03-24 16:20 ` David Woodhouse
2017-03-23 14:29 ` [PATCH 18/17] x86: Use generic pci_mmap_resource_range() David Woodhouse
2017-03-24 11:40 ` [PATCH 00/17] PCI resource mmap cleanup David Woodhouse
2017-03-24 16:57 ` Luck, Tony
2017-03-24 16:20 ` Arnd Bergmann
2017-04-04 22:43 ` Bjorn Helgaas
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