netdev - howto use ioremap

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-next>] [day] [month] [year] [list]

Date:	Sat, 31 May 2008 11:02:54 +0200
From:	Brice Goglin <brice@...i.com>
To:	LKML <linux-kernel@...r.kernel.org>, netdev@...r.kernel.org,
	"venkatesh.pallipadi@...el.com" <venkatesh.pallipadi@...el.com>
Subject: howto use ioremap_wc?

Hello,

We're looking at using ioremap_wc() in myri10ge. No drivers seem to be
using it yet, so I'd like to get some clarification regarding ioremap_wc
failures, MTRR and so on.

What we currently do is mtrr_add() and then ioremap. Depending on the
mtrr_add() success, we use the "wc_fifo" or regular PIO with fences to
submit requests to the NIC. How are we supposed to switch this to
ioremap_wc?

Are we sure that if the arch supports _wc, it does not return success
when the underlying plain ioremap worked but setting up _wc() failed? If
so, why does it revert to ioremap_nocache when PAT isn't enabled?

Can we keep the mtrr_add() in the regular path? Or are we supposed to
drop it when the arch provides ioremap_wc and it did not fail?

thanks,
Brice

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html