kboot: Create segment handling code at main level

[imp]

Summary

Create segment handling code up to the top level. Move it all into
seg.c, and make necessary adjustments for it being in a new file,
including inventing print_avail() and first_avail() to print the array
and find the first large enough memory hole.aarch64 will use this,
and I'll refactor the other platforms to use it as I make them work.

Sponsored by: Netflix

[imp]

rebase / refactor / redo

[kevans]

I somewhat wish we could reuse sys/kern/subr_physmem here just to have one less memory range segment manager to audit; it's not quite flexible enough for kboot's needs, though.

stand/kboot/seg.c

24

Should probably error check this malloc and below realloc; failure's probably unlikely, I'm guessing just panic so we can detect that particular problem a bit earlier rather than when we try to dereference it?

177

[imp]

panic on no mem, update comment

[imp]

stand/kboot/seg.c

24

agreed.

[imp]

\m to \n

[imp]

In D38308#871390, @kevans wrote:

I somewhat wish we could reuse sys/kern/subr_physmem here just to have one less memory range segment manager to audit; it's not quite flexible enough for kboot's needs, though.

I wish we could as well... but we both add new memory areas, as well as remove areas from inside of those added areas, which subr_physmem doesn't do.