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

[Eric Farman]

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 <address@hidden> 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