From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frank Rowand Subject: Re: [RFC/PATCH] of: Mark property::value as const Date: Thu, 23 Feb 2017 15:23:19 -0800 Message-ID: <58AF6EE7.5050008@gmail.com> References: <20170214025040.23955-1-stephen.boyd@linaro.org> <58AF3E06.4030701@gmail.com> <58AF4D03.7020908@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Rob Herring Cc: Stephen Boyd , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: devicetree@vger.kernel.org On 02/23/17 14:09, Rob Herring wrote: > On Thu, Feb 23, 2017 at 2:58 PM, Frank Rowand wrote: >> On 02/23/17 11:54, Frank Rowand wrote: >>> On 02/13/17 18:50, Stephen Boyd wrote: >>>> The 'blob' we pass into populate_properties() is marked as const, >>>> but we cast that const away when we assign the result of >>>> fdt_getprop_by_offset() to pp->value. Let's mark value as const >>>> instead, so that code can't mistakenly write to the value of the >>>> property that we've so far advertised as const. >>>> >>>> Unfortunately, this exposes a problem with the fdt resolver code, >>>> where we overwrite the value member of properties of phandles to >>>> update them with their final value. Add a comment for now to >>>> indicate where we're potentially writing over const data. >>> >>> The resolver should not be over writing anything in the FDT. I'll >>> look at what is going on there. >>> >>> The FDT we expose to user space should be the FDT we booted with, >>> not something later modified. >> >> It seems that /sys/firmware/fdt is not documented. I'll look into >> fixing that. > > That's because the "official" interface is /proc/device-tree/ which is > now a symlink. IIRC, it is documented to use /proc/device-tree, not > the sysfs path. > > Rob > . > Documentation/ABI/testing/sysfs-firmware-ofw describes /sys/firmware/devicetree/* but not /sys/firmware/fdt It also describes the /proc/device-tree symlink to /sys/firmware/devicetree/base as the official stable ABI, as you mentioned. So it is just fdt that I have not found the documentation for. -Frank -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html