Re: [RFC PATCH v6] Documentation/arch: Add Documentation/arch-features.txt

[Josh Triplett <josh-iaAMLnmF4UmaiuxdJuQwMA@public.gmane.org>]

On Wed, May 13, 2015 at 09:27:57AM -0700, Josh Triplett wrote:
> How likely is this to get out of date?  Are people going to remember to
> patch this when they add a feature to their architecture?  If
> they found out they had work to do by reading this file, which is the
> goal, then they'll likely remember to edit the file; however, if they
> find the feature and fix it without knowing about the file, will someone
> notice?
> 
> Is there any way we can *generate* this file from Kconfig?  Can we
> extract the necessary "this is possible to enable" or "this arch selects
> this symbol" information from Kconfig, and together with the list of
> symbols for features needing architecture support, generate the table?

Just tried this.  Looks like it's pretty trivial for most of these
features: just make ARCH=thearch allyesconfig, then look for the config
symbol in the result.

For instance, after doing "make ARCH=alpha allyesconfig":

~/src/linux$ grep -x 'CONFIG_ARCH_HAS_ELF_RANDOMIZE=y' .config || echo TODO
TODO

~/src/linux$ grep -x 'CONFIG_GENERIC_CLOCKEVENTS=y' .config || echo TODO
CONFIG_GENERIC_CLOCKEVENTS=y

This seems easy to turn into a shell script or Python script, given a list of
feature descriptions and corresponding config symbols, as well as a list of
architectures.

- Josh Triplett