Re: [PATCH V8 06/44] mm/pkeys: Add Kconfig options for PKS

[Dave Hansen]

On 1/28/22 15:10, Ira Weiny wrote:
> This issue is that because PKS users are in kernel only and are not part of the
> architecture specific code there needs to be 2 mechanisms within the Kconfig
> structure.  One to communicate an architectures support PKS such that the user
> who needs it can depend on that config as well as a second to allow that user
> to communicate back to the architecture to enable PKS.

I *think* the point here is to ensure that PKS isn't compiled in unless
it is supported *AND* needed.  You have to have architecture support
(ARCH_HAS_SUPERVISOR_PKEYS) to permit features that depend on PKS to be
enabled.  Then, once one ore more of *THOSE* is enabled,
ARCH_ENABLE_SUPERVISOR_PKEYS comes into play and actually compiles the
feature in.

In other words, there are two things that must happen before the code
gets compiled in:

1. Arch support
2. One or more features to use the arch support