xen/arm: gic-v2: Only create GICv2m node when there are GICv2m frame available

Xen will crash on platform where GICv2m is not available with the
following error:

(XEN) Can't find ranges property for the gic node
(XEN) Device tree generation failed (-15).
(XEN)
(XEN) ****************************************
(XEN) Panic on CPU 0:
(XEN) Could not set up DOM0 guest OS
(XEN) ****************************************

This is because the property "ranges" may not be present in the GIC
when there are no GICv2m frames.

Skip the creation of the GICv2m node when the hardware does not
support it.

This fixes boot after commit "xen/arm: Export GICv2m register frames to
DOM0 by device tree".

Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Acked-by: Wei Chen <wei.chen@linaro.org>

diff --git a/xen/arch/arm/gic-v2.c b/xen/arch/arm/gic-v2.c
index 2c1c0baa26be11153627db9118e12573a2042c9a..4e2f4c7b67ef7b1be25d8dbd64a08f9bd3d6d35b 100644 (file)
--- a/xen/arch/arm/gic-v2.c
+++ b/xen/arch/arm/gic-v2.c
@@ -669,6 +669,10 @@ static int gicv2m_make_dt_node(const struct domain *d,
     const struct dt_device_node *v2m = NULL;
     const struct v2m_data *v2m_data;
 
+    /* It is not necessary to create the node if there are not GICv2m frames */
+    if ( list_empty(&gicv2m_info) )
+        return 0;
+
     /* The sub-nodes require the ranges property */
     prop = dt_get_property(gic, "ranges", &len);
     if ( !prop )