On Tue, Feb 14, 2023 at 09:58:59AM -0700, Simon Glass wrote: > Hi Tom, > > On Tue, 14 Feb 2023 at 09:31, Tom Rini <[email protected]> wrote: > > > > On Sun, Feb 12, 2023 at 04:16:04PM -0700, Simon Glass wrote: > > > > > At present kconfig writes out several files, including: > > > > > > auto.conf - CONFIG settings used by make > > > autoconf.h - header file used by C code > > > > > > This works well but is a bit ugly in places, for example requiring the use > > > of a SPL_TPL_ macro in Makefiles to distinguish between options intended > > > for SPL and U-Boot proper. > > > > > > Update the kconfig tool to also output separate files for each phase: e.g. > > > auto_spl.conf and autoconf_spl.h > > > > > > These are similar to the existing files, but drop the SPL_ prefix so that > > > SPL_TPL_ is not needed. It also allows the CONFIG_IS_ENABLED() macro to be > > > simplified, in a later patch, eventually replacing it with IS_ENABLED(). > > > > > > When CONFIG_FOO is used within SPL, it means that FOO is enabled in that > > > SPL phase. For example if CONFIG_SPL_FOO is enabled in the Kconfig, that > > > means that CONFIG_FOO will be enabled in the SPL phase. So the SPL builds > > > can just use CONFIG_FOO to check it. There is no need to use > > > CONFIG_SPL_FOO or CONFIG_IS_ENABLED() anymore. > > > > > > This of course means that if there is a need to access a PPL symbol from > > > an SPL build, there is no way to do it. To copy with that, we need a > > > CONFIG_PPL_FOO to be visibilty to all SPL builds. > > > > > > So this change also adds new PPL_ output for U-Boot proper (Primary > > > Program Loader). So every CONFIG_FOO that is enabled in PPL also has a > > > CONFIG_PPL_FOO > > > > > > This allows SPL to access the TEXT_BASE for U-Boot proper, for example, so > > > it knows where to load it. There are about 30 places where this is needed, > > > in addition to TEXT_BASE. The environment has the same problem, adding > > > another dozen or so caes in include/config_distro_bootcmd.h but it has > > > been decided to ignore that for now. > > > > > > The feature is controlled by an environment variable, since it seems to be > > > bad form to add flags to the conf tool. > > > > > > Rebuild the autoconf files if the split config is not present. This allows > > > building this commit as part of a chain, without generating build errors. > > > > > > These changes may benefit from some reworking to send upstream, e.g. to > > > use a struct for the 'arg' parameter. > > > > > > Signed-off-by: Simon Glass <[email protected]> > > > > This patch, I think, is where my largest problem is. We go from being > > able to say "if CONFIG_SPL_FOO is undefined, it is false" to "we must > > define CONFIG_SPL_FOO to false". There's around 150 cases of this, with > > the series. Why can we not extend the PPL logic (which I'm not super > > happy with, but, I understand and I think an audit of everything > > not-TEXT_BASE should be fairly straight forward), to say that if > > CONFIG_FOO exists and CONFIG_SPL_FOO does not exist, say CONFIG_SPL_FOO > > is now false. > > Well it is all about choices. > > We don't have to add a CONFIG_SPL_xxx to tell Kconfig that the PPL > symbol controls all phases. We can use the conf_nospl file instead. > But then the entire description is not in Kconfig. Of course, we might > expect that some of those things in conf_nospl might end up needing to > be controlled in SPL, so perhaps that file would shrink? Not sure > about that, though. > > It isn't just SPL , BTW. We might have any xPL symbol defined. > > I suppose you are thinking of something like: > > #define CONFIG_IS_ENABLED(x) IS_ENABLED(CONFIG_ ## xpl_prefix ## x) || > ( IS_ENABLED(CONFIG_ ## x) && !IS_ENABLED(CONFIG_ SPL_ ## x) && > !IS_ENABLED(CONFIG_TPL_ ##x) ..) > > But how do we deal with Makefiles? We still end up with the SPL_TPL_ stuff.
I see it as a very useful feature that today if we don't set CONFIG_xPL_FOO, it evaluates to false, anywhere we need it to. In all of the prep work for split config, I think we've seen one case where we got things wrong (in that it lead to failure). Split config build is doing a whole bunch of things to then remove this feature. And the series intentionally ignores the Makefile design issue / feature of wrapping large chunks with a check for being/not-being in an xPL_BUILD phase. > Yes, adding PPL moves a step forward and reduces the audit to only > uses of PPL, instead of the whole Kconfig. > > This series does get us closer to separate configs (it is really easy > to see what is enabled in each build just by looking at the > auto_xpl.conf files) and I think those 150 exceptions are not a big > price to pay. > > Ultimately I am coming to the view that we should extend the Kconfig > language to support multiple build phases, using a 'phase' property. > Zephyr is going to need it too, fairly soon[1]. > > Regards, > Simon > > [1] https://github.com/zephyrproject-rtos/zephyr/issues/54534 Yes, if the Kconfig language moves in a new direction, it would be good to follow and use that. -- Tom
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