linux-kernel - Re: [RFC] asm-generic/pci_iomap.h: make custom PCI BAR requirements explicit

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]

Message-ID: <20150829152505.GA23449@infradead.org>
Date:	Sat, 29 Aug 2015 08:25:05 -0700
From:	Christoph Hellwig <hch@...radead.org>
To:	"Luis R. Rodriguez" <mcgrof@...not-panic.com>
Cc:	arnd@...db.de, linux-arch@...r.kernel.org, mingo@...nel.org,
	schwidefsky@...ibm.com, heiko.carstens@...ibm.com,
	linux-s390@...r.kernel.org, bp@...e.de, linux@...ck-us.net,
	linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
	rostedt@...dmis.org, "Luis R. Rodriguez" <mcgrof@...e.com>
Subject: Re: [RFC] asm-generic/pci_iomap.h: make custom PCI BAR requirements
 explicit

On Fri, Aug 28, 2015 at 05:17:27PM -0700, Luis R. Rodriguez wrote:
> From: "Luis R. Rodriguez" <mcgrof@...e.com>
> 
> The S390 architecture requires a custom pci_iomap() implementation
> as the asm-generic implementation assumes there are disjunctions
> between PCI BARs, and on S390 PCI BAR are not disjunctive, S390 requires
> the bar parameter in order to find the corresponding device and create
> the mapping cookie.
> 
> This clash with the asm-generic pci_iomap() implementation is implicit,
> there are no current semantics to make this incompatability explicit.
> Make the S390 PCI BAR non-disjunction incompatibility explicit, and
> also pave the way for alternative incompatibilities to be defined.
> 
> While at it, as with the ioremap*() variants, since we have no clear
> semantics yet well defined provide a solution for them that returns
> NULL. This allows architectures to move forward by defining pci_ioremap*()
> variants without requiring immediate changes to all architectures. Each
> architecture then can implement their own solution as needed and
> when they get to it.

Now that you have the config symbol available why not move the S390
implementation to generic code based on that can kill of
asm/pci_iomap.h?  Seems like we're really not dealing with something
inherent to the architecture, but two possible implementations based
on architecture constraints.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/