HEADS UP: powerpc64 kernel format change [booted a PowerMac G5 quad-core][those problems booting some kernel variants: new info]

[Mark Millard]

Nathan, you had the below written about my problems with booting my builds of, say, 10.1-STABLE  (kernel="kernel10.1S" in /boot/loaderl.conf) without involving the kernel from my build of 10.1-RELEASE-p5 (kernel="kernel10.1RE" or sometimes kernel="kernel" in /boot/loader.conf), where kernel="kernel10.1RE" in /boot/loader.conf boots just fine...

> So this has to be some kind of icache issue. If you unload and reload 
> the *same* kernel, does it also help?
> -Nathan

(Part of the evidence was: Using kernel="kernel10.1RE" in /boot/loader.conf, stopping at the 10sec prompt, unloading, and doing "boot kernel 10.1S" lets my 10.1-STABLE builds boot that will not boot directly.)


Well I've got a little more information from a different direction: A way to create the problem when building my 10.1-RELEASE-p5 kernel is to enable VERBOSE_SYSINIT. More specifically the comparison/contrast I've done so far is...



I added the following 3 lines to my GENERIC64vtsc for my 10.1-RELEASE-p5 source tree (no other changes elsewhere at all)

options 	VERBOSE_SYSINIT
options 	BOOTVERBOSE=1
options 	BOOTHOWTO=RB_VERBOSE

and rebuilt kernel the via KERNCONF=GENERIC64vtsc INSTKERNNAME=kernel the resulting kernel load fails if referenced by /boot/loader.conf via kernel="kernel" line. The %SRR0 address value listed is the same as for kernel10.1S: 1c277fc. But booting using kernel="kernel10.1RE" in /boot/loader.conf, stopping at the 10sec wait, unloading, and typing "boot kernel" boots fine --just like "boot kernel10.1S".

Note: GENERIC64vtsc has option DDB enabled (and GBD too). (This is associated my with my information gathering for early G5 boot crashes/hangups.)

Note: This is the first time I've ever tried any of those 3 options. My kernel10.1S build was not based on them.

Then I changed the 3 lines by just commenting out the first of the 3 that I had added

#options 	VERBOSE_SYSINIT
options 	BOOTVERBOSE=1
options 	BOOTHOWTO=RB_VERBOSE

and rebuilt via KERNCONF=GENERIC64vtsc INSTKERNNAME=kernel again. The resulting /boot/kernel/... boots just fine when kernel="kernel" is used in /boot/loader.conf : no need for using kernel10.1RE or for stopping to do anything special.



===
Mark Millard
markmi at dsl-only.net