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:	Mon, 29 Sep 2008 10:20:18 +0100
From:	Alan Cox <alan@...rguk.ukuu.org.uk>
To:	Grant Grundler <grundler@...isc-linux.org>
Cc:	Arjan van de Ven <arjan@...radead.org>,
	linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org
Subject: Re: [PATCH] pci: introduce users of ioremap_pcibar()

> FTR, I like this interface better since most drivers use ioremap() instead
> of ioremap_nocache(). They generally should be using the latter.

And pci_iomap is cleaner still. Plus pcim_iomap does resource tracking so
all the masses of special case error code/cleanup can get cut down.

> Is there any easy way to tell if the device driver should be using
> uncached mappings vs cacheable mappings?
> (Just from looking at the source code)

There isn't one.

> For storage/networking/audio cards I'm comfortable with the generalization
> that they all should use uncacheable mappings (I'm sure there are some
> exceptions.) I'm not with video devices.

There are exceptions - I2O for example and there are other cards that use
write merging when possible beyond video. Also btw vidoe depends on the
chip - if you cache/write merge the framebuffer on a Voodoo 1/2 card you
must be in 24/32bit video modes for example.

Generally though PCI = controlled by hardware = uncached

Alan
--
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/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ