Re: [PATCH v4 10/19] Introduce asm-generic/*.h files

[Christoffer Dall <christoffer.dall@linaro.org>]

On Mon, Jun 09, 2014 at 01:39:06PM +0200, Andrew Jones wrote:
> On Mon, Jun 09, 2014 at 11:54:48AM +0200, Andrew Jones wrote:
> > On Mon, Jun 09, 2014 at 11:08:32AM +0200, Christoffer Dall wrote:
> > > On Mon, Jun 09, 2014 at 10:23:27AM +0200, Andrew Jones wrote:
> > > > On Fri, Jun 06, 2014 at 08:39:09PM +0200, Christoffer Dall wrote:
> > > > > On Thu, Apr 10, 2014 at 06:56:51PM +0200, Andrew Jones wrote:
> > > > > > Architecture neutral code may need to call low-level io accessors,
> > > > > > or use spinlocks. Create a generic io.h to ensure those accessors
> > > > > > are defined, and a generic spinlock.h that complains when included,
> > > > > > as we can't write a generic spinlock. These files can be overridden
> > > > > > or extended by architecture specific versions placed in
> > > > > > lib/$ARCH/asm/.
> > > > > > 
> > > > > > Signed-off-by: Andrew Jones <drjones@redhat.com>
> > > > > > ---
> > > > > > v4: introduce lib/asm symlink to get rid of #ifdef __arm__,
> > > > > >     add spinlock.h too
> > > > > > v3: wrt to io.h (was libio.[ch]) only
> > > > > >     - get rid of CONFIG_64BIT, replace with asserts
> > > > > >     - get rid of {read,write}_len() [libio.c]
> > > > > >     - fix bad *64_to_cpu macros
> > > > > > ---
> > > > > >  .gitignore                 |   1 +
> > > > > >  Makefile                   |   6 +-
> > > > > >  configure                  |  11 ++++
> > > > > >  lib/asm-generic/io.h       | 154 +++++++++++++++++++++++++++++++++++++++++++++
> > > > > >  lib/asm-generic/spinlock.h |   4 ++
> > > > > >  5 files changed, 173 insertions(+), 3 deletions(-)
> > > > > >  create mode 100644 lib/asm-generic/io.h
> > > > > >  create mode 100644 lib/asm-generic/spinlock.h
> > > > > > 
> > > > > > diff --git a/.gitignore b/.gitignore
> > > > > > index 775d0dfd8263e..e21939a8771e9 100644
> > > > > > --- a/.gitignore
> > > > > > +++ b/.gitignore
> > > > > > @@ -9,6 +9,7 @@ patches
> > > > > >  .stgit-*
> > > > > >  cscope.*
> > > > > >  *.swp
> > > > > > +/lib/asm
> > > > > >  /config.mak
> > > > > >  /*-run
> > > > > >  /test.log
> > > > > > diff --git a/Makefile b/Makefile
> > > > > > index fba58e36f272f..51cacdac00615 100644
> > > > > > --- a/Makefile
> > > > > > +++ b/Makefile
> > > > > > @@ -76,11 +76,11 @@ libfdt_clean:
> > > > > >  	$(LIBFDT_objdir)/.*.d
> > > > > >  
> > > > > >  distclean: clean libfdt_clean
> > > > > > -	$(RM) config.mak $(TEST_DIR)-run test.log msr.out cscope.*
> > > > > > +	$(RM) lib/asm config.mak $(TEST_DIR)-run test.log msr.out cscope.*
> > > > > >  
> > > > > > -cscope: common_dirs = lib lib/libfdt
> > > > > > +cscope: common_dirs = lib lib/libfdt lib/asm lib/asm-generic
> > > > > >  cscope:
> > > > > >  	$(RM) ./cscope.*
> > > > > > -	find $(TEST_DIR) lib/$(TEST_DIR) $(common_dirs) -maxdepth 1 \
> > > > > > +	find -L $(TEST_DIR) lib/$(TEST_DIR) $(common_dirs) -maxdepth 1 \
> > > > > >  		-name '*.[chsS]' -print | sed 's,^\./,,' > ./cscope.files
> > > > > >  	cscope -bk
> > > > > > diff --git a/configure b/configure
> > > > > > index 6cfc64943f6e6..8a81bf92e27b7 100755
> > > > > > --- a/configure
> > > > > > +++ b/configure
> > > > > > @@ -95,6 +95,17 @@ if [ $exit -eq 0 ]; then
> > > > > >  fi
> > > > > >  rm -f lib_test.c
> > > > > >  
> > > > > > +# link lib/asm for the architecture
> > > > > > +rm -f lib/asm
> > > > > > +asm=asm-generic
> > > > > > +if [ -d lib/$arch/asm ]; then
> > > > > > +	asm=$arch/asm
> > > > > > +elif [ -d lib/$testdir/asm ]; then
> > > > > > +	asm=$testdir/asm
> > > > > 
> > > > > why do you need this elif?  can you not make sure arch is always set?
> > > > 
> > > > arch is always set, but there's a chance some arch may not add it's own
> > > > lib/$arch dir. It's a pretty small chance... but the elif shouldn't hurt.
> > > > 
> > > If we don't have any code that uses this scheme now then let's now have
> > > Makefile rules that encourages non-standard behavior (unless I'm missing
> > > the point and this provides a 'feature' for specific archs or something
> > > like that).
> > >
> > 
> > It would be something of a feature for some imaginary arch. However, as
> > that imaginary arch doesn't exist right now, then I'm fine removing it.
> > Whoever makes the imaginary arch a reality can bring it back.
> > 
> 
> Oh wait, it's actually not imaginary (just unused). x86 is an example of
> such a testdir that doesn't == arch. So, if either i386 or x86_64 wanted
> to use lib/asm, then they need this elif.
> 
ah, ok.  I'll shut up then.
-Christoffer