gpart: Add warning when the start sector is too low.
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Authored by imp on Oct 17 2023, 2:28 AM.

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emaste
marcel

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rG2cbda736cea8: gpart: Add warning when the start sector is too low.

Summary

Add a warning if the starting sector is too low. The standard requires
that at least 16k is reserved for the GPT Partition Array, but some
tools produce GPT images with fewer than the required number of reserved
sectors.

Diff Detail

Repository

rG FreeBSD src repository

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Build Status

Buildable 54050
Build 50940: arc lint + arc unit

Event Timeline

imp requested review of this revision.Oct 17 2023, 2:28 AM

imp created this revision.

imp added a parent revision: D42246: gpart: More nuance for GPT support.

Harbormaster completed remote builds in B54024: Diff 128888.Oct 17 2023, 2:28 AM

I imagine "some tools" is only mkimg w/o D42245.

jrtc27 added a subscriber: jrtc27.Oct 17 2023, 6:46 AM

jrtc27 added inline comments.

sys/geom/part/g_part_gpt.c
1047
1055	Condition divides by sectorsize, this print doesn't

In D42247#963725, @emaste wrote:

I imagine "some tools" is only mkimg w/o D42245.

I've seen python scripts that create embedded SD images for things like mediatek or similar that also violate these rules. They code is quite ugly...
I imagine no mainstream tool does this, but I'll also note that EDK II likes our old mkimg images and isn't bothered by them, suggesting that they had to cope in the past as well...

review feedback

Harbormaster completed remote builds in B54050: Diff 128935.Oct 17 2023, 3:45 PM

EDK II likes our old mkimg images and isn't bothered by them

I think there's not much value in a consumer (system firmware, OS partition handling code) in rejecting a GPT that violates the spec and has a too-low start LBA so I guess it's not too surprising that EDK II accepts it.

This revision was not accepted when it landed; it landed in state Needs Review.Oct 16 2024, 12:15 AM

Closed by commit rG2cbda736cea8: gpart: Add warning when the start sector is too low. (authored by imp). · Explain Why

This revision was automatically updated to reflect the committed changes.

imp added a commit: rG2cbda736cea8: gpart: Add warning when the start sector is too low..