Re: ARM build with v3.7-rc3 with CONFIG_XEN_GNTDEV=m

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Tue, Nov 06, 2012 at 10:39:59PM +0100, Ian Campbell wrote:
> On Tue, 2012-11-06 at 21:19 +0000, Konrad Rzeszutek Wilk wrote:
> > Hey Stefano,
> > 
> > I setup a cross ARM build system so that the generic changes won't cause build issues
> > on ARM (and actually caught a bug with fallback.o being enabled there - I've a fix
> > for that).
> > 
> > But more interestingly the build system I do also makes a variations of config entries.
> > So there is the allmodules, allyes, allyes, but all Xen drivers are modules, etc.
> > 
> > I found out that with:
> > CONFIG_XEN_GNTDEV=m
> > I get this
> > 
> > ERROR: "HYPERVISOR_event_channel_op" [drivers/xen/xen-gntdev.ko] undefined!
> > 
> > If I make it CONFIG_XEN_GNTDEV=y the issue disappears. Any thoughts?
> 
> I wonder if this is to do with missing EXPORT_SYMBOL for the various
> things in hypercall.S ? Quite possibly this is the same thing as Russell
> King just reported r.e. privmcd?

I think so, I was unable to find the code for HYPERVISOR_event_channel_op
until I did a grep for 'hypercall' and found the hypercall.S file :-(

Will add an EXPORT_SYMBOL_GPL for said issue and see if that fixes it.



> 
> > 
> > (FYI, if you want to do this on v3.7-rc4 please apply this patch to your tree)
> > 
> > 
> > commit e1a982642262820d68779c06de64f8857a040f5a
> > Author: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> > Date:   Tue Nov 6 15:49:27 2012 -0500
> > 
> >     xen/generic: Disable fallback build on ARM.
> >     
> >     As there is no need for it (the fallback code is for older
> >     hypervisors and they won't run under ARM), and also b/c
> >     we get:
> >     
> >     drivers/xen/fallback.c: In function 'xen_event_channel_op_compat':
> >     drivers/xen/fallback.c:10:19: error: storage size of 'op' isn't known
> >     drivers/xen/fallback.c:15:2: error: implicit declaration of function '_hypercall1' [-Werror=implicit-function-declaration]
> >     drivers/xen/fallback.c:15:19: error: expected expression before 'int'
> >     drivers/xen/fallback.c:18:7: error: 'EVTCHNOP_close' undeclared (first use in this function)
> >     drivers/xen/fallback.c:18:7: note: each undeclared identifier is reported only once for each function it appears in
> >     .. and more
> >     
> >     Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> > 
> > diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
> > index 46de6cd..273d2b9 100644
> > --- a/drivers/xen/Makefile
> > +++ b/drivers/xen/Makefile
> > @@ -1,8 +1,8 @@
> >  ifneq ($(CONFIG_ARM),y)
> > -obj-y	+= manage.o balloon.o
> > +obj-y	+= manage.o balloon.o fallback.o
> >  obj-$(CONFIG_HOTPLUG_CPU)		+= cpu_hotplug.o
> >  endif
> > -obj-y	+= grant-table.o features.o events.o fallback.o
> > +obj-y	+= grant-table.o features.o events.o
> >  obj-y	+= xenbus/
> >  
> >  nostackp := $(call cc-option, -fno-stack-protector)
>