linux-kernel - Re: [PATCH V5 1/3] ARM64 LPC: Indirect ISA port IO introduced

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 09 Nov 2016 22:33:17 +0100
From:   Arnd Bergmann <arnd@...db.de>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     John Garry <john.garry@...wei.com>, mark.rutland@....com,
        devicetree@...r.kernel.org, lorenzo.pieralisi@....com,
        benh@...nel.crashing.org, minyard@....org,
        gabriele.paoloni@...wei.com, catalin.marinas@....com,
        zhichang.yuan02@...il.com, liviu.dudau@....com,
        linuxarm@...wei.com, Will Deacon <will.deacon@....com>,
        linux-kernel@...r.kernel.org, zourongrong@...il.com,
        bhelgaas@...gle.com, robh+dt@...nel.org, xuwei5@...ilicon.com,
        linux-serial@...r.kernel.org, linux-pci@...r.kernel.org,
        olof@...om.net, kantyzc@....com,
        "zhichang.yuan" <yuanzhichang@...ilicon.com>
Subject: Re: [PATCH V5 1/3] ARM64 LPC: Indirect ISA port IO introduced

On Wednesday, November 9, 2016 11:29:46 AM CET John Garry wrote:
> On 08/11/2016 22:35, Arnd Bergmann wrote:
> > On Tuesday, November 8, 2016 4:49:49 PM CET Will Deacon wrote:
> >> On Tue, Nov 08, 2016 at 04:33:44PM +0000, John Garry wrote:
> >>> On 08/11/2016 16:12, Will Deacon wrote:
> >>>> On Tue, Nov 08, 2016 at 11:47:07AM +0800, zhichang.yuan wrote:
> >
> >>>> Is there no way to make this slightly more generic, so that it can be
> >>>> re-used elsewhere? For example, if struct extio_ops was common, then
> >>>> you could have the singleton (which maybe should be an interval tree?),
> >>>> type definition, setter function and the BUILD_EXTIO invocations
> >>>> somewhere generic, rather than squirelled away in the arch backend.
> >>>>
> >>> The concern would be that some architecture which uses generic higher-level
> >>> ISA accessor ops, but have IO space, could be affected.
> >>
> >> You're already adding a Kconfig symbol for this stuff, so you can keep
> >> that if you don't want it on other architectures. I'm just arguing that
> >> plumbing drivers directly into arch code via arm64_set_extops is not
> >> something I'm particularly fond of, especially when it looks like it
> >> could be avoided with a small amount of effort.
> >
> > Agreed, I initially suggested putting this into arch/arm64/, but there isn't
> > really a reason why it couldn't just live in lib/ with the header file
> > bits moved to include/asm-generic/io.h which we already use.
> >
> 
> Right, Zhichang will check the logistics of this. The generic io.h is 
> quite clean, so as long as you don't mind new build switches of this 
> nature being added, it should be ok; and we'll plan on moving extio.h 
> into include/asm-generic as well.

I think all we need is an #ifdef CONFIG_something around the existing
defintion, with the alternative being "extern" declarations, after that
all the interesting logic can sit in a file in lib/.

	Arnd