Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Wed, 18 Jan 2023 14:10:37 -0800
From:   Andrew Morton <akpm@linux-foundation.org>
To:     "Herton R. Krzesinski" <herton@redhat.com>
Cc:     linux-kernel@vger.kernel.org, vbabka@suse.cz, jforbes@redhat.com,
        dzickus@redhat.com, scweaver@redhat.com
Subject: Re: [PATCH] tools/vm: allow users to provide additional
 cflags/ldflags
Message-Id: <20230118141037.3d5e6df707125353435bfbae@linux-foundation.org>
In-Reply-To: <Y8f4aUx7P45qHlpl@localhost.localdomain>
References: <20230116224921.4106324-1-herton@redhat.com>
        <20230117165326.3e693a12a45a1962ca0c40af@linux-foundation.org>
        <Y8f4aUx7P45qHlpl@localhost.localdomain>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Precedence: bulk

On Wed, 18 Jan 2023 10:47:21 -0300 "Herton R. Krzesinski" <herton@redhat.com> wrote:

> On Tue, Jan 17, 2023 at 04:53:26PM -0800, Andrew Morton wrote:
> > On Mon, 16 Jan 2023 19:49:21 -0300 "Herton R. Krzesinski" <herton@redhat.com> wrote:
> > 
> > > Right now there is no way to provide additional cflags/ldflags when
> > > building tools/vm binaries. And using eg. make CFLAGS=<options> will
> > > override the CFLAGS being set in the Makefile, making the build fail
> > > since it requires the include of the ../lib dir (for libapi).
> > > 
> > > This change then allows you to specify:
> > > CFLAGS=<options> LDFLAGS=<options> make V=1 -C tools/vm
> > > 
> > > And the options will be correctly appended as can be seen from the
> > > make output.
> > > 
> > > ...
> > >
> > > --- a/tools/vm/Makefile
> > > +++ b/tools/vm/Makefile
> > > @@ -8,8 +8,8 @@ TARGETS=page-types slabinfo page_owner_sort
> > >  LIB_DIR = ../lib/api
> > >  LIBS = $(LIB_DIR)/libapi.a
> > >  
> > > -CFLAGS = -Wall -Wextra -I../lib/
> > > -LDFLAGS = $(LIBS)
> > > +CFLAGS += -Wall -Wextra -I../lib/
> > > +LDFLAGS += $(LIBS)
> > >  
> > 
> > I think EXTRA_CFLAGS is more conventional?
> > 
> 
> I was looking and there is no standard under tools/
> 
> Some use it, some not. To given an example of what uses CFLAGS:
> tools/arch/x86/kcpuid/Makefile:override CFLAGS += -O2 -Wall -I../../../include
> tools/arch/x86/intel_sdsi/Makefile:override CFLAGS += -O2 -Wall
> tools/iio/Makefile:override CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
> tools/thermal/tmon/Makefile:override CFLAGS += $(shell $(PKG_CONFIG) --cflags $(STATIC) panelw ncursesw 2> /dev/null || \
> tools/gpio/Makefile:override CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
> tools/pci/Makefile:CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
> tools/spi/Makefile:CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
> tools/wmi/Makefile:CFLAGS += -D__EXPORTED_HEADERS__ -I../../include/uapi -I../../include
> tools/io_uring/Makefile:CFLAGS += -Wall -Wextra -g -D_GNU_SOURCE
> tools/counter/Makefile:override CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
> 
> I can however use EXTRA_CFLAGS, not a problem, eg. doing instead:
> CFLAGS = -Wall -Wextra -I../lib/ $(EXTRA_CFLAGS)
> LDFLAGS = $(LIBS) $(EXTRA_LDFLAGS)
> 
> Let me know and I'll resend the patch using EXTRA_* instead.

Well drat, I was hoping you'd decide ;)

I'll grab it as-is, thanks.

(of course, we could always use both!)