linux-kernel - Re: [PATCH v6 4/4] Documentation: ABI: /sys/firmware/devicetree/overlays

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: <235F6C23-4962-4114-BCB2-4279E775E23E@konsulko.com>
Date:	Wed, 21 Oct 2015 00:02:15 +0300
From:	Pantelis Antoniou <pantelis.antoniou@...sulko.com>
To:	Rob Herring <robherring2@...il.com>
Cc:	Frank Rowand <frowand.list@...il.com>,
	Matt Porter <mporter@...sulko.com>,
	Koen Kooi <koen@...inion.thruhere.net>,
	Guenter Roeck <linux@...ck-us.net>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-api@...r.kernel.org" <linux-api@...r.kernel.org>
Subject: Re: [PATCH v6 4/4] Documentation: ABI: /sys/firmware/devicetree/overlays

Hi Rob,

> On Oct 20, 2015, at 23:56 , Rob Herring <robherring2@...il.com> wrote:
> 
> On Tue, Oct 20, 2015 at 2:13 PM, Pantelis Antoniou
> <pantelis.antoniou@...sulko.com> wrote:
>> Documentation ABI entry for overlays sysfs entries.
>> 
>> Signed-off-by: Pantelis Antoniou <pantelis.antoniou@...sulko.com>
>> ---
>> .../ABI/testing/sysfs-firmware-devicetree-overlays | 40 ++++++++++++++++++++++
>> 1 file changed, 40 insertions(+)
>> create mode 100644 Documentation/ABI/testing/sysfs-firmware-devicetree-overlays
>> 
>> diff --git a/Documentation/ABI/testing/sysfs-firmware-devicetree-overlays b/Documentation/ABI/testing/sysfs-firmware-devicetree-overlays
>> new file mode 100644
>> index 0000000..adc4068
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/sysfs-firmware-devicetree-overlays
>> @@ -0,0 +1,40 @@
>> +What:          /sys/firmware/devicetree/overlays/
>> +Date:          October 2015
>> +Contact:       Pantelis Antoniou <pantelis.antoniou@...sulko.com>
>> +Description:
>> +               This directory contains the applied device tree overlays of
>> +               the running system, as directories of the overlay id.
>> +
>> +               enable: The master enable switch, by default is 1, and when
>> +                       set to 0 it cannot be re-enabled for security reasons.
>> +
>> +               The discussion about this switch takes place in:
>> +               http://comments.gmane.org/gmane.linux.drivers.devicetree/101871
>> +
>> +               Kees Cook:
>> +               "Coming from the perspective of drawing a bright line between
>> +               kernel and the root user (which tends to start with disabling
>> +               kernel module loading), I would say that there at least needs
>> +               to be a high-level one-way "off" switch for the interface so
>> +               that systems that have this interface can choose to turn it off
>> +               during initial boot, etc."
>> +
>> +What:          /sys/firmware/devicetree/overlays/<id>
>> +Date:          October 2015
>> +Contact:       Pantelis Antoniou <pantelis.antoniou@...sulko.com>
>> +Description:
>> +               Each directory represents an applied overlay, containing
>> +               the following attribute files.
>> +
>> +               can_remove: The attribute set to 1 means that the overlay can
>> +                           be removed, while 0 means that the overlay is being
>> +                           overlapped therefore removal is prohibited.
>> +
>> +What:          /sys/firmware/devicetree/overlays/<id>/<fragment-name>/
>> +Date:          October 2015
>> +Contact:       Pantelis Antoniou <pantelis.antoniou@...sulko.com>
>> +Description:
>> +               Each of these directories contain information about of the
>> +               particular overlay fragment.
>> +
>> +               target: The full-path of the target of the fragment
>> --
> 
> What happened to attributes within the fragment dir?
> 

There’s a single attribute named target that contains the target of the fragment.

At the moment this is the only attribute. I eventually intent to put the full contents of the overlay fragment
there as /sysfs/firmware/devicetree/base does, but this would make things quite complicated for now.

Should I add a What: line for that too? 

> Rob

Regards

— Pantelis

--
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/