netdev - Re: [PATCH 2/3] net: socionext: Add Synquacer NetSec driver

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: <20171130.124234.1467691580228393484.davem@davemloft.net>
Date:   Thu, 30 Nov 2017 12:42:34 -0500 (EST)
From:   David Miller <davem@...emloft.net>
To:     ard.biesheuvel@...aro.org
Cc:     dan.j.williams@...el.com, will.deacon@....com,
        jassisinghbrar@...il.com, netdev@...r.kernel.org,
        devicetree@...r.kernel.org, arnd.bergmann@...aro.org,
        robh+dt@...nel.org, mark.rutland@....com,
        jaswinder.singh@...aro.org
Subject: Re: [PATCH 2/3] net: socionext: Add Synquacer NetSec driver

From: Ard Biesheuvel <ard.biesheuvel@...aro.org>
Date: Thu, 30 Nov 2017 17:37:27 +0000

> Well, the whole point of using memremap() instead of ioremap() is that
> the region has memory semantics, i.e., we read the MAC address and the
> DMA engine microcode from it. If memremap() itself is flawed in this
> regard, I agree we should fix it. But as I understand it, this is
> really an implementation problem in memremap() [the fact that it falls
> back to ioremap()] and not a problem in this driver.
> 
> So what alternative would you propose in this case?
> 
> BTW, this should be IOREMAP_WC not IOREMAP_WT, because the EEPROM on
> the platform in question does not tolerate cached mappings (or rather,
> shareable mappings). ioremap_wt() happens to result in device mappings
> rather than writethrough cacheable mappings, but this is another
> problem in itself. Once arm64 fixes ioremap_wt(), this code will no
> longer work on the SynQuacer SoC.

It doesn't "fall back", it directly uses ioremap_wt() for non-RAM
mappings.

It you look, most architectures do a "#define iomrep_wt ioremap"