linux-kernel - Re: [PATCH] Open Firmware device tree virtual filesystem

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:	Tue, 02 Jan 2007 15:57:05 +1100
From:	Benjamin Herrenschmidt <benh@...nel.crashing.org>
To:	David Miller <davem@...emloft.net>
Cc:	segher@...nel.crashing.org, hch@...radead.org,
	linux-kernel@...r.kernel.org, devel@...top.org, dmk@...x.com,
	wmb@...mworks.com, jg@...top.org
Subject: Re: [PATCH] Open Firmware device tree virtual filesystem


> I think there is high value in an OFW filesystem representation
> that gives you _EXACTLY_ what the OFW command line prompt does
> when you try to traverse the device tree from there, and that
> is what openpromfs tries to do.

Except that every OFW implementation I have here shows you different
things for the same original binary data :-)

> If you want raw access, use a character device or a similar auxilliary
> access to the data items.  Another idea is to provide a seperate file
> operation (such as ioctl) on the OFW property files in order to fetch
> things raw and in binary.
> 
> When I get some binary data out of a procfs or sysfs file I feel like
> strangling somebody.  I'm grovelling around in a filesystem from the
> command line so that I can get some information as a user.  If you
> don't give me text I can't tell what the heck it is.
> 
> Simple system tools should not need to interpret binary data in
> order to provide access to simple structured data like this, that's
> just stupid.

I would agree with you if the data was properly typed in the first place
but it's not, thus you end up with heuristics and I hate heuristics in
the kernel :-) Now, that's also why everybody on ppc has "lsprop" at
hand which does the "pretty printing" thing.

I like being able to have a simple way (ie. tar /proc/device-tree) to
tell user to send me their DT and have in the end an exact binary
representation so I can actually dig for problems, like a wrong phandle
in an interrupt-map or stuff like that...

Cheers,
Ben.


-
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/