linux-kernel - Re: [dmidecode] [Patch v3] firmware: dmi-sysfs: add SMBIOS entry point area raw attribute

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: <20150308181140.288dfa88@endymion.delvare>
Date:	Sun, 8 Mar 2015 18:11:40 +0100
From:	Jean Delvare <jdelvare@...e.de>
To:	Ard Biesheuvel <ard.biesheuvel@...aro.org>
Cc:	"Ivan.khoronzhuk" <ivan.khoronzhuk@...ballogic.com>,
	dmidecode-devel@...gnu.org,
	Ivan Khoronzhuk <ivan.khoronzhuk@...aro.org>,
	Matt Fleming <matt.fleming@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Leif Lindholm <leif.lindholm@...aro.org>,
	Mark Salter <msalter@...hat.com>,
	Grant Likely <grant.likely@...aro.org>
Subject: Re: [dmidecode] [Patch v3] firmware: dmi-sysfs: add SMBIOS entry
 point area raw attribute

On Sun, 8 Mar 2015 14:53:04 +0100, Ard Biesheuvel wrote:
> On 8 March 2015 at 12:31, Jean Delvare <jdelvare@...e.de> wrote:
> > On Sat, 07 Mar 2015 22:53:32 +0200, Ivan.khoronzhuk wrote:
> >> The specification doesn't oblige firmware to provide two entry points.
> >> An implementation may provide either the 32-bit entry point or the 64-bit
> >> entry point, or both. For compatibility with existing SMBIOS parsers, an
> >> implementation should provide the 32-bit entry point, but it's not required.
> >
> > I expect most implementations will do, as it's trivial to implement.
> 
> Not quite. First of all, some 64-bit ARM systems do not have any
> system RAM below 4 GB, so there is not way they can implement the
> 32-bit entry point.

I didn't know that, thanks for the notice. No big deal anyway, these
systems did not support SMBIOS before version 3.0 so there cannot be
any regression on these systems.

> Also, the 64-bit entry point does not limit the
> structure size or the entire table to 64 KB like the 32-bit one does,
> so it may be necessary to create a whole separate table with a subset
> of the contents of the real table to stay within limits for the 32-bit
> entry point.

I doubt this is an issue in practice. I have been around for quite some
time now and the largest table I've ever seen was 9043 byte long, which
is nowhere close to the limit.

> And the 32-bit entry point could well be 3.0 anyway, if
> it uses any of the new enum values for the data items that were
> undefined before 3.0.

This is true but irrelevant to the discussion.

Thanks,
-- 
Jean Delvare
SUSE L3 Support
--
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/