On 1/2/24 4:15 AM, karl@aspodata.se wrote:
> Eli Schwartz:
> [...]
>> +Systems which have /usr and / on separate filesystems have always required a
>> +dedicated initramfs to bring up both partitions. Systems where both /usr and /
>> +are on the same filesystem may use an initramfs if they wish, or choose not
>> +to.
> [...]
> 
> Well, that is not technically correct, just have the required kernel 
> drivers (eg. AHCI and ext2/4) compiled in and use the same busybox
> commands as in the initrd, but placed in /, to bring up the system
> to the point that /usr is mounted.
> 
> I have a static dev, compiled in drivers, busybox init and mount, and
> separate / and /usr on a box here, works perfectly well.
>  Soo, add a clause about what gentoo supports out of the box and that
> you can make it work if you wish.
>  If there is a general wish I can write an article about how to make
> it work.


You need the required kernel drivers regardless of having /usr on a
separate partition.

The problem here is solely about after the kernel has booted, mounted
the / filesystem, and run init -- init needs to fully bring the system
up. While it's no doubt possible to do this with finely-crafted busybox
usage, there's a lot of ways it could break if you aren't *very*
careful, and that should not require ongoing support.

It's firmly in the "you break it, you bought it" category. But I have no
objection if it's mentioned on the wiki in the initramfs article or
somewhere similar.

I don't think this is a blocker for dropping hacks like
usr-ldscript.eclass usage, though.


-- 
Eli Schwartz