linux-kernel - Re: [patch 5/6] ps3: BD/DVD/CD-ROM Storage 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]

Date:	Fri, 13 Jul 2007 16:19:54 +0200
From:	Arnd Bergmann <arnd@...db.de>
To:	linuxppc-dev@...abs.org
Cc:	James Bottomley <James.Bottomley@...eleye.com>,
	Geert Uytterhoeven <Geert.Uytterhoeven@...ycom.com>,
	linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org,
	Alessandro Rubini <rubini@...ion.unipv.it>,
	Paul Mackerras <paulus@...ba.org>,
	Jens Axboe <jens.axboe@...cle.com>
Subject: Re: [patch 5/6] ps3: BD/DVD/CD-ROM Storage Driver

On Friday 13 July 2007, James Bottomley wrote:
> 
> > IC.
> > 
> >   - flush_kernel_dcache_page() is a no-op on ppc64
> >     (ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE is defined on parisc only).
> > 
> >   - For reference, drivers/scsi/ipr.c (another ppc64 driver) just uses a plain
> >     kmap/memcpy/kunmap sequence
> > 
> > So what should I do?
> 
> Ask someone who knows the architecture ... Anton, Paulus or Benh ... I'm
> fairly certain PPC is VIPT and will need some kind of alias
> resolution ... perhaps its associative enough not to let the aliases be
> a problem.

I'm pretty sure that no ppc64 machine needs alias resolution in the kernel,
although some are VIPT. Last time we discussed this, Segher explained it
to me, but I don't remember which way Cell does it. IIRC, it automatically
flushes cache lines that are accessed through aliases.

It's probably a good idea to have the flush_kernel_dcache_page() in there
anyway, if only to serve as an example for people that copy it into
architecture-independent drivers, same as what we do for the
k{,un}map_atomic() that is also not required on ppc64.

	Arnd <><
-
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/