Re: [PATCH v4 4/4] Documentation: ABI: /sys/firmware/devicetree/overlays
From: Rob Herring <hidden>
Date: 2015-06-15 13:24:33
Also in:
linux-devicetree, lkml
On Fri, Jun 12, 2015 at 2:38 PM, Pantelis Antoniou [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Documentation ABI entry for overlays sysfs entries. Signed-off-by: Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org> --- .../ABI/testing/sysfs-firmware-devicetree-overlays | 35 ++++++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-firmware-devicetree-overlaysdiff --git a/Documentation/ABI/testing/sysfs-firmware-devicetree-overlays b/Documentation/ABI/testing/sysfs-firmware-devicetree-overlays new file mode 100644 index 0000000..be2d28b --- /dev/null +++ b/Documentation/ABI/testing/sysfs-firmware-devicetree-overlays@@ -0,0 +1,35 @@ +What: /sys/firmware/devicetree/overlays/ +Date: March 2015 +Contact: Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org> +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. + +What: /sys/firmware/devicetree/overlays/<id> +Date: March 2015 +Contact: Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org> +Description: + Each directory represents an applied overlay, containing + the following attribute files. + + 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."
Doesn't this below up above with "enable"?
+ + targets: A file containing the list of targets of each overlay + with each line containing a target.
We have OF nodes in sysfs now. Would it be more useful if we created links to the target nodes instead of having a list of names?
+ + 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. + -- 1.7.12