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

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How likely is this to get out of date?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