arm: initial Xen support

- Basic hypervisor.h and interface.h definitions.
- Skeleton enlighten.c, set xen_start_info to an empty struct.
- Make xen_initial_domain dependent on the SIF_PRIVILIGED_BIT.

The new code only compiles when CONFIG_XEN is set, that is going to be
added to arch/arm/Kconfig in patch #11 "xen/arm: introduce CONFIG_XEN on
ARM".

Changes in v3:

- improve comments.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

2 files changed, 36 insertions, 0 deletions

diff --git a/arch/arm/xen/Makefile b/arch/arm/xen/Makefile
new file mode 100644
index 000000000000..0bad594b1490
--- /dev/null
+++ b/arch/arm/xen/Makefile
@@ -0,0 +1 @@
+obj-y           := enlighten.o
diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
new file mode 100644
index 000000000000..c53554032a60
--- /dev/null
+++ b/arch/arm/xen/enlighten.c
@@ -0,0 +1,35 @@
+#include <xen/xen.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/memory.h>
+#include <xen/platform_pci.h>
+#include <asm/xen/hypervisor.h>
+#include <asm/xen/hypercall.h>
+#include <linux/module.h>
+
+struct start_info _xen_start_info;
+struct start_info *xen_start_info = &_xen_start_info;
+EXPORT_SYMBOL_GPL(xen_start_info);
+
+enum xen_domain_type xen_domain_type = XEN_NATIVE;
+EXPORT_SYMBOL_GPL(xen_domain_type);
+
+struct shared_info xen_dummy_shared_info;
+struct shared_info *HYPERVISOR_shared_info = (void *)&xen_dummy_shared_info;
+
+DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);
+
+/* TODO: to be removed */
+__read_mostly int xen_have_vector_callback;
+EXPORT_SYMBOL_GPL(xen_have_vector_callback);
+
+int xen_platform_pci_unplug = XEN_UNPLUG_ALL;
+EXPORT_SYMBOL_GPL(xen_platform_pci_unplug);
+
+int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
+                               unsigned long addr,
+                               unsigned long mfn, int nr,
+                               pgprot_t prot, unsigned domid)
+{
+        return -ENOSYS;
+}
+EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range);