Bug 512020

Summary:	sys-firmware/seabios-1.7.4: Is the toolchain warning still valid?
Product:	Gentoo Linux	Reporter:	Fabian Henze <flyser42>
Component:	[OLD] Core system	Assignee:	Doug Goldstein (RETIRED) <cardoe>
Status:	RESOLVED WONTFIX
Severity:	normal	CC:	virtualization
Priority:	Normal
Version:	unspecified
Hardware:	All
OS:	Linux
Whiteboard:
Package list:		Runtime testing required:	---

Description Fabian Henze 2014-06-01 10:05:41 UTC

I intended to build seabios with USE="-binary" and was greeted with the following warning:
 * You have decided to compile your own SeaBIOS. This is not
 * supported by upstream unless you use their recommended
 * toolchain (which you are not).
 * 
 * If you are intending to use this build with QEMU, realize
 * you will not receive any support if you have compiled your
 * own SeaBIOS. Virtual machines subtly fail based on changes
 * in SeaBIOS.

Is that warning still valid in 2014? I could not find anything in the seabios documentation that specifically requires a certain toolchain.
If it is, could you add a link to the relevant documentation to the elog warning?

Reproducible: Always

Comment 1 SpanKY gentoo-dev

2014-08-04 02:34:09 UTC

yes, overall it's an issue because the output has to be byte-for-byte exact.  if even one byte changes, you can see weird behavior wrt VM migration/resumes.  this is why we default to using the precompiled binary everywhere -- try to maximize the chance that things "just work".

note that a lot of the code is assembly/low level C, and it's only used as the BIOS at boot, so applying your own optimization levels won't realistically make a lick of a difference.  it also won't help with things like hardening because those apply only to userland software (`ls` and such), not to OS software (BIOS, kernel, etc...).

Comment 2 Fabian Henze 2014-08-04 09:16:48 UTC

My intention was to apply a patch