Re: [PATCH 2/2] xen/arm: Fix compile errors when drivers are compiled as modules.

Stefano Stabellini
2012-11-07T10:26:36Z

On Tue, 6 Nov 2012, Konrad Rzeszutek Wilk wrote:
> We end up with:
>
> ERROR: "HYPERVISOR_event_channel_op" [drivers/xen/xen-gntdev.ko] undefined!
> ERROR: "privcmd_call" [drivers/xen/xen-privcmd.ko] undefined!
> ERROR: "HYPERVISOR_grant_table_op" [drivers/net/xen-netback/xen-netback.ko] undefined!
>
> and this patch exports said function (which is implemented in hypercall.S).
>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Thank you very much for going out of your way to fix this issue (I am
currently at LinuxCon).

> arch/arm/xen/enlighten.c | 5 +++++
> 1 files changed, 5 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
> index 59bcb96..96d969d 100644
> --- a/arch/arm/xen/enlighten.c
> +++ b/arch/arm/xen/enlighten.c
> @@ -166,3 +166,8 @@ void free_xenballooned_pages(int nr_pages, struct page **pages)
> *pages = NULL;
> }
> EXPORT_SYMBOL_GPL(free_xenballooned_pages);
> +
> +/* In the hypervisor.S file. */
> +EXPORT_SYMBOL_GPL(HYPERVISOR_event_channel_op);
> +EXPORT_SYMBOL_GPL(HYPERVISOR_grant_table_op);
> +EXPORT_SYMBOL_GPL(privcmd_call);

I think the patch is OK and I tested it: it fixes the issue reported
by Russell.
However I am wondering, does it actually make sense only to export 3
hypercalls among the set implemented in hypercall.S?
Maybe it does make sense only to export a subset, but I wouldn't
necessarly do the differentiation here, I would just export all the
hypercalls implemented in hypercalls.S.
In fact if we separate the hypercalls in two sets, I would like to
see a similar differentiation on x86 too.