Re: [GIT PULL] kbuild changes for v4.9-rc1

[Adam Borowski]

On Mon, Oct 17, 2016 at 05:59:51PM +1100, Nicholas Piggin wrote:
> On Mon, 17 Oct 2016 08:51:31 +0200
> Adam Borowski <kilobyte@xxxxxxxxxx> wrote:
> > On Mon, Oct 17, 2016 at 02:57:09PM +1100, Nicholas Piggin wrote:
> > > On Sat, 15 Oct 2016 17:22:05 -0700 Omar Sandoval <osandov@xxxxxxxxxxx> wrote:  
> > > > So this has broken all module loading for me. I get the following dmesg
> > > > spew:
> > > > ...
> > > > [    4.586914] scsi_mod: no symbol version for memset
> > > > [    4.587920] scsi_mod: Unknown symbol memset (err -22)
> > > > [    4.588443] scsi_mod: no symbol version for ___preempt_schedule
> > > > [    4.589026] scsi_mod: Unknown symbol ___preempt_schedule (err -22)
> > > > ...
> > > > 
> > > > Reverting 784d5699eddc ("x86: move exports to actual definitions") fixes
> > > > it for me. This is with GCC 6.2.1, binutils 2.27, attached config.  
> > > 
> > > Thanks for the report. Could you try this patch and see if it helps?  
> > [patch snipped]
> > 
> > Omar probably won't wake up in quite a while, so I've tested the patch.
> > Alas, doesn't help.  Similar spew (for the few modules I don't have =y),
> > while reverting 784d5699eddc fixes it for me too.
> 
> Forgot to engage my brain before posting.
> 
> Architectures will need to have an include/asm/asm-prototypes.h that
> defines or #include<>s C-style prototypes for exported asm functions.
> We can do an asm-generic version for the common ones like memset so
> there's not a lot of pointless duplication there.
> 
> Care to do a patch for x86?

Sure, did so.  With the prototypes added, your patch works!
Tested on a handful of modules, and one out-of-tree (virtualbox).
I didn't try a 32-bit build.

Note that powerpc already has an include/asm/asm-prototypes.h which might or
might not be what you want.  It doesn't have memset and co, for example.

Anyway, here's my stab at x86: