Re: [Qemu-devel] [PATCH for-2.10 0/1] Fix "make clean" for s390 target

[Thomas Huth <thuth@redhat.com>]

On 15.08.2017 10:01, Thomas Huth wrote:
> On 15.08.2017 09:03, Cornelia Huck wrote:
>> On Tue, 15 Aug 2017 07:02:10 +0200
>> Thomas Huth <thuth@redhat.com> wrote:
>>
>>> On 14.08.2017 22:44, Eric Farman wrote:
>>>> How often does one really do a "make clean" ?  Rather infrequently,
>>>> as I only stumbled on this today.
>>>>
>>>> Perhaps I have missed the RM variable somewhere, as I see similar syntax
>>>> in some of the tests/tcg/ Makefiles, but I don't see it being set here.
>>>> My configure statement isn't terribly interesting, just enabling debug
>>>> for an s390x target, and as such there's no RM variable in its output.
>>>> I'll trust that Thomas will chime in with where it should have been.
>>>> In the meantime, this does the trick for me.  
>>>
>>> RM is one of the variables that should be pre-initialized by Make, and
>>> AFAIK should be used to increase portability (well, it's likely not
>>> important for QEMU since we require a posix-shell like built environment
>>> anyway).
>>>
>>> According to the info page of Make, chapter "10.3 Variables Used by
>>> Implicit Rules":
>>>
>>> `RM'
>>>      Command to remove a file; default `rm -f'.
>>>
>>> I've also checked it again and "make clean" works fine here (using GNU
>>> Make 3.82). Which version of Make (and Linux distro) are you using?
>>
>> Interesting. It fails for me with GNU Make 3.82 on my RHEL guest as
>> well.
>>
>>> Anyway, maybe I also simply missed something, so I'm certainly also fine
>>> with the patch to revert it to "rm -f".
>>
>> Given that other bios makefiles use rm -f as well, let's just change
>> back until we figure out what's wrong.
> 
> I just discovered that it fails for me as well when I do "make clean"
> from the top directory. So far I was only doing "make clean" after doing
> a "cd pc-bios/s390-ccw" first, and that works fine. Weird. Something
> seems to unset the RM variable in our build system, but I fail to find
> the spot where this happens...

Ok, just found it: It's this line in rules.mak:

MAKEFLAGS += -rR

The parameter -R disables the built-in variables, so RM can indeed not
work here. Sorry, I wasn't aware of that setting yet, so your patch is
indeed the right fix here (or we should maybe define RM in rules.mak, too).

 Thomas