[SLOF] [PATCH] Remove dependency on cpu/@0 for booting

[Nikunj A Dadhania]

Segher Boessenkool <segher at kernel.crashing.org> writes:

> On Wed, Jul 27, 2016 at 12:42:23PM +0530, Nikunj A Dadhania wrote:
>> Segher Boessenkool <segher at kernel.crashing.org> writes:
>> 
>> > On Wed, Jul 27, 2016 at 12:06:06PM +0530, Nikunj A Dadhania wrote:
>> >> Segher Boessenkool <segher at kernel.crashing.org> writes:
>> >> 
>> >> > On Wed, Jul 27, 2016 at 09:47:47AM +0530, Nikunj A Dadhania wrote:
>> >> >>  \ Fixup timebase frequency from device-tree
>> >> >>  : fixup-tbfreq
>> >> >> -    " /cpus/@0" find-device
>> >> >> +    " /cpus" find-device
>> >> >> +    get-node child ?dup 0= IF ABORT" start-cpu not found" THEN
>> >> >> +    set-node
>> >> >
>> >> > ABORT" has an IF built in.  It also empties the stack, so this is just
>> >> >
>> >> >    get-node child dup 0= ABORT" start-cpu not found"
>> >> 
>> >> Sure.
>> 
>> i understood the IF part, but why not ?dup ?
>
> It's a tiny bit slower, but much more importantly, it is harder to read.
> Well, in my opinion, anyway.  ?DUP works fine here of course, but why
> bother, the ABORT will clean the whole stack no matter what.

Thanks for clarification.

>> >> > What guarantees this finds the "start-cpu"?
>> >> 
>> >> QEMU does not allow to remove last CPU.
>> >
>> > But that is not the same thing?
>> 
>> Dont get you, can you please elaborate?
>
> Oh, sorry.
>
> The code tries to find *a* cpu.  But the error message says "start-cpu
> not found".  The code is not looking for a "start-cpu", a user getting
> that error message will waste time scratching his head before looking
> at the code (if he is lucky enough to do look at the code).
>
> Just say what is *actually* wrong, what did not work ;-)

Crystal clear now :-)

" CPU not found"

Regards,
Nikunj