HEADS UP: powerpc64 kernel format change [booted a PowerMac G5 quad-core]

[Mark Millard]

Nathan W. suggested "If you unload and reload the *same* kernel, does it also help?".

I can not do that test for 10.1-STABLE or 11.0-CURRENT as the initial kernel because either of the following lines in /boot/loader.conf fails to get to the "any other key for a command prompt" stage: I get no valid opportunity to try unload then boot if I start with these kernels.

kernel="kernel10.1S"
kernel="kernel11C"

In other words: after the error one is back in the context for "mac-boot" and "shut-down" and the like (Apple's context, not FreeBSD's). For example "boot ud:2,\ppc\bootinfo.txt" at that point for booting from a memory stick does not work, giving some message about being unable to do the memory allocation it needs or some such. (I do not remember the details.)

The only one of the 3 buildworld build kernel installkernel installworld sequences that lets me reboot far enough to get to the "any other key for a command prompt" is:

kernel="kernel10.1RE"

and from there the unload then boot sequence works for booting all 3.

(Later power-off/power-on's get the same boot-attempt initial results as the initial "shutdown -r now" for all 3 kernels. The initial reboot is not unique.)

kernel10.1RE also has no trouble booting if I do not stop it.

I'll note that all 3 kernels do output the line that shows text= data= syms=[...]. The crashing ones crash between that line and the following "any other key for a command prompt" line.


I had described how I boot the problematical kernels:

> And I use /boot/loader.conf to control which kernel is initially started, such as:
>
> $ more /boot/loader.conf
> kernel="kernel10.1RE"
> verbose_loading="YES"
> kern.vty=vt
>
> The kernel10.RE one boots and runs fine with any of the 3 vintages of loader. Listing kernel10.1S or kernel11C in loader.conf instead gets the SRR0/SRR1 failures referenced above, even when loader (and world) is from the matching buildworld.
>
> So I boot as above (kernel10.1RE) but use the "any other key for a command prompt" to stop it and then (for example):
>
> unload
> boot kernel11C
>
> and that boots and runs fine if I've done the 11-CURRENT installworld before the reboot.

I had also described the errors reported for kernel10.1S and kernel11C:

> Like for 10.1-STABLE, for 11-CURRENT (-R277990) the sequence buildworld, buildkernel, installkernel, installworld, reboot failed to boot before getting to the "any other key for a command prompt" stage, although the SRR0 figure was different.
>
> %SRR0: 00000000.01c287ac (10.1-STABLE reports 1c277fc)
> %SRR1: 10000000.00003030

Usually that is indicated as a Invalid memory access but sometimes as a Decrementer exception.


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