pmbr: Only load the first 545k rather than error out
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Authored by imp on Nov 25 2023, 6:52 PM.

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Reviewers

manu
emaste
kevans
tsoome

Commits

rG49028a1db2de: pmbr: Only load the first 545k rather than error out
rGc596126a5d3d: pmbr: Only load the first 545k rather than error out

Summary

It would be nice to have larger boot partitions for ESPs to live in one
day. It's trivial to carve out 5M 10M or 200M when provisioning, but
logistical issues may make it hard to do it after the fact. So only warn
when the partition is > 545k. If we ever grow the boot loader larger
than that, then it will be responsible for loading the rest anyway.

Diff Detail

Repository

rG FreeBSD src repository

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Event Timeline

imp created this revision.Nov 25 2023, 6:52 PM

Herald added a reviewer: manu. · View Herald TranscriptNov 25 2023, 6:52 PM

Herald added a subscriber: dab. · View Herald Transcript

imp requested review of this revision.Nov 25 2023, 6:52 PM

Harbormaster completed remote builds in B54629: Diff 130584.Nov 25 2023, 6:52 PM

imp added reviewers: emaste, kevans, tsoome.Nov 25 2023, 6:56 PM

tsoome accepted this revision.Nov 25 2023, 6:59 PM

This revision is now accepted and ready to land.Nov 25 2023, 6:59 PM

imp added inline comments.Nov 25 2023, 7:04 PM

stand/i386/pmbr/pmbr.S
234	We're at 438 of 440 usable code bytes here. Better error message for this requires shaving elsewhere.

tsoome added inline comments.Nov 25 2023, 7:06 PM

stand/i386/pmbr/pmbr.S
234	if the larger than 512k partitions are common, this message can just be dropped (and limit documented in gpart bootcode and handbook).

imp added inline comments.Nov 26 2023, 12:47 AM

stand/i386/pmbr/pmbr.S
234	Yes indeed. It will be in newer installations.... Still not entirely sure, though, this is a good idea since maybe just have the installer make 2 partitions. Disk space is cheap, and the embedded market doesn't go through bsdinstall... and even if it did, we make 2 parts by default and it can be overridden... Though, there's not a huge amount in the embedded market that's x86, but too low end to have UEFI booting.