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SubjectRe: Allow (O=...) from file
On Wed, Dec 05, 2007 at 09:31:26PM -0600, Jay Cliburn wrote:
> On Wed, 5 Dec 2007 22:00:03 +0100
> Sam Ravnborg <sam@ravnborg.org> wrote:
>
> > On Tue, Dec 04, 2007 at 09:04:33PM -0600, Jay Cliburn wrote:
> > > Sam,
> > >
> > > This piece of the top-level Makefile in current git causes an
> > > out-of-tree driver Makefile to fail.
> > >
> > > 101 ifdef O
> > > 102 ifeq ("$(origin O)", "command line")
> > > 103 KBUILD_OUTPUT := $(O)
> > > 104 endif
> > > 105 endif
> > >
> > > The out-of-tree driver Makefile contains an O=... directive that
> > > (correctly) does _not_ specify the kernel source dir, and apparently
> > > isn't overridden by the command line either. If in the above
> > > Makefile snippet I change "command line" to "file", my out-of-tree
> > > make succeeds. What do you think about allowing O= to come from a
> > > file in addition to the command line?
> >
> > When you change "command line" to "file" you actually makes kbuild
> > ignore the O=... value which is why it succeeds.
>
> I'm puzzled by your statement. Isn't the opposite true? When using
> "command line", doesn't the following happen?
>
> 1. My makefile sets O=/foo
> 2. My makefile invokes your makefile with O=/foo
> 3. Your makefile ignores my O=/foo because it requires O=/foo to
> originate from the command line
> 4. KBUILD_OUTPUT never gets set to /foo and we hit the error
>
> OTOH, if I use "file":
> 1. My makefile sets O=/foo
> 2. My makefile invokes your makefile with O=/foo
> 3. Your makefile accepts my O=/foo because it requires O=/foo to
> originate from another makefile
> 4. KBUILD_OUTPUT gets set to /foo and my make succeeds
>
> This all used to work the last time I tried it, which was sometime
> during 2.6.23 development, IIRC. Isn't the current structure going to
> break just about all out-of-tree driver builds?

Jay - can I ask you to try out following patch.
If is a workaround for the root issue but this is the sort of
fix I would like to push this late in -rc.

Sam

diff --git a/Makefile b/Makefile
index a5252f4..7fb1a2c 100644
--- a/Makefile
+++ b/Makefile
@@ -118,9 +118,6 @@ saved-output := $(KBUILD_OUTPUT)
KBUILD_OUTPUT := $(shell cd $(KBUILD_OUTPUT) && /bin/pwd)
$(if $(KBUILD_OUTPUT),, \
$(error output directory "$(saved-output)" does not exist))
-# Check that OUTPUT directory is not the same as where we have kernel src
-$(if $(filter-out $(KBUILD_OUTPUT),$(shell /bin/pwd)),, \
- $(error Output directory (O=...) specifies kernel src dir))

PHONY += $(MAKECMDGOALS) sub-make

diff --git a/scripts/mkmakefile b/scripts/mkmakefile
index ee39fac..9ad1bd7 100644
--- a/scripts/mkmakefile
+++ b/scripts/mkmakefile
@@ -11,6 +11,12 @@


test ! -r $2/Makefile -o -O $2/Makefile || exit 0
+# Only overwrite automatically generated Makefiles
+# (so we do not overwrite kernel Makefile)
+if ! grep -q Automatically $2/Makefile
+then
+ exit 0
+fi
echo " GEN $2/Makefile"

cat << EOF > $2/Makefile

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