(This one I'll actually let sit for a longer period of time)
At the moment, hintmode and envmode are used to indicate whether static hints or static env have been provided in the kernel config(5) and the static versions are mutually exclusive with loader(8)-provided environment. hintmode *can* be reconfigured later to pull from the dynamic environment, thus taking advantage of the loader(8) or post-kmem environment setting.
This changeset fixes both problems at once to move us from a semi-confusing state to a consistent state: if an environment file, hints file, or loader(8) environment are provided, we use them in a well-known order of precedence:
- loader(8) environment
- static environment
- static hints file
Once the dynamic environment is setup this becomes a moot point. The loader(8) and static environments are merged (respecting the above order of precedence), and the static hints are merged in on an as-needed basis after the dynamic environment has been setup.
Hints lookup are changed to respect all of the above. Before the dynamic environment is setup, lookups use the above-mentioned order and fallback to the next environment if a matching hint is not found. Once the dynamic environment is setup, that is used on its own since it captures all of the above information plus any dynamic kenv settings that came up later in boot.
The following tangentially related changes were made to res_find:
- A hintp cookie is now passed in so that related searches continue using the chain of environments (or dynamic environment) without relying on global state
- All three environments will be searched if they actually have valid hints to use, rather than just choosing the first environment that actually had a hint and rolling with that only
The static_env.disabled and static_hints.disabled environment settings will no longer be honored (pending discussion? I tend to think it makes little sense when we can honor all environments), and the hintmode sysctl has been ripped out.