powerpc: 32BIT vs. 64BIT (PPC32 vs. PPC64)

[Randy Dunlap]

On 07/06/2018 06:45 PM, Benjamin Herrenschmidt wrote:
> On Thu, 2018-07-05 at 14:30 -0700, Randy Dunlap wrote:
>> Hi,
>>
>> Is there a good way (or a shortcut) to do something like:
>>
>> $ make ARCH=powerpc O=PPC32 [other_options] allmodconfig
>>   to get a PPC32/32BIT allmodconfig
>>
>> and also be able to do:
>>
>> $make ARCH=powerpc O=PPC64 [other_options] allmodconfig
>>   to get a PPC64/64BIT allmodconfig?
> 
> Hrm... O= is for the separate build dir, so there much be something
> else.
> 
> You mean having ARCH= aliases like ppc/ppc32 and ppc64 ?

Yes.

> That would be a matter of overriding some .config defaults I suppose, I
> don't know how this is done on other archs.
> 
> I see the aliasing trick in the Makefile but that's about it.
> 
>> Note that arch/x86, arch/sh, and arch/sparc have ways to do
>> some flavor(s) of this (from Documentation/kbuild/kbuild.txt;
>> sh and sparc based on a recent "fix" patch from me):
> 
> I fail to see what you are actually talking about here ... sorry. Do
> you have concrete examples on x86 or sparc ? From what I can tell the
> "i386" or "sparc32/sparc64" aliases just change SRCARCH in Makefile and
> 32 vs 64-bit is just a Kconfig option...

Yes, your summary is mostly correct.

I'm just looking for a way to do cross-compile builds that are close to
ppc32 allmodconfig and ppc64 allmodconfig.


>> x86: i386 for 32 bit, x86_64 for 64 bit
>> sh: sh for 32 bit, sh64 for 64 bit
>> sparc: sparc32 for 32 bit, sparc64 for 64 bit

I saw the powerpc merge-config targets after I sent this original email.
I can do my own homebrew that I prefer over those, though.


thanks,
-- 
~Randy