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

[Eric Farman <farman@linux.vnet.ibm.com>]

On 08/15/2017 04:26 AM, Thomas Huth wrote:
> 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?

Not that it matters now, but make 4.1 on F24

>>>
>>> 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).

Excellent find, Thomas!  I was not aware of that either.  Thanks to both 
you and Cornelia for this.

  - Eric