loader.efi architecture for replacing boot1.efi

[Eric McCorkle]

On 12/16/2017 19:17, Richard Perini wrote:

>> No. It doesn't. You're assuming that if we fail, the system won't boot.
>> That's false. If we fail to boot device X, it's our job to fail so that if
>> there's a Y or a Z it can be next. We have no knowledge of whether the user
>> would prefer Y or Z as the next one to try, but the boot manager that runs
>> inside every single UEFI firmware does and it will go to the next one. Y
>> might be a recovery disk or copy of a freebsd memory stick release and Z
>> might be a redundant copy of X to use in cases where X fails. Or vice
>> versa. Do we want to boot to the installer? Not as a first choice, but
>> maybe as a last resort. But we should let UEFI orchestrate the retries.
>> Trying to second guess is fundamentally wrong, especially in UEFI where the
>> boot order and boot recovery stuff is so extensively and particularly
>> defined. Having fought the "oh, I'm going to guess" code in boot1.efi for
>> over a year and after having it consistently pick the wrong thing to boot
>> on some tiny fraction of the hundreds of systems I've had deployed give me
>> strong empirical data that shows the guessing too hard bit is actually
>> actively harmful. I've thought about this a lot. I've thought through all
>> the supported scenarios. I've written up documents and solicited feedback.
>> Nobody to date has said "oh no! I really want the random installed system
>> roulette! I love it! Don't kill it."
>>
>> Warner
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> 
> To add support to Warner, as an administrator of 50+ FreeBSD systems on
> a variety of hardware and disk configs, I totally support Warner's arguments.
> Having the loader trying to guess in the case of unusual setups when it
> can't find a kernel __on the same device as the loader__ causes grief.  If 
> you want to have your thing boot that way, then configure it to do so, or 
> present a menu of boot options.  
> 

Ok, I've updated my review, simplifying the search code.  The option to
search all devices is only enabled by a preprocessor macro at this point.

I have a mostly-complete follow-on, which adds parsing of args from the
boot.config files.

Anyway, the state of my review at this point is enough that I'm
unblocked on the GELI work.