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

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

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?

(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)