[XEN v1 2/9] xen/arm: Define translate_dt_address_size() for the translation between u64 and paddr_t

[Ayan Kumar Halder <ayan.kumar.halder@xxxxxxx>]

paddr_t may be u64 or u32 depending of the type of architecture.
Thus, while translating between u64 and paddr_t, one should check that the
truncated bits are 0. If not, then raise an appropriate error.

Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@xxxxxxx>
---
 xen/arch/arm/include/asm/platform.h | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/xen/arch/arm/include/asm/platform.h 
b/xen/arch/arm/include/asm/platform.h
index 997eb25216..6be1549f09 100644
--- a/xen/arch/arm/include/asm/platform.h
+++ b/xen/arch/arm/include/asm/platform.h
@@ -42,6 +42,32 @@ struct platform_desc {
     unsigned int dma_bitsize;
 };
 
+static inline int translate_dt_address_size(u64 *dt_addr, u64 *dt_size,
+                                            paddr_t *addr, paddr_t *size)
+{
+#ifdef CONFIG_ARM_PA_32
+    if ( dt_addr && (*dt_addr >> PADDR_SHIFT) )
+    {
+        dprintk(XENLOG_ERR, "Error in DT. Invalid address\n");
+        return -ENXIO;
+    }
+
+    if ( dt_size && (*dt_size >> PADDR_SHIFT) )
+    {
+        dprintk(XENLOG_ERR, "Error in DT. Invalid size\n");
+        return -ENXIO;
+    }
+#endif
+
+    if ( dt_addr && addr )
+        *addr = (paddr_t) (*dt_addr);
+
+    if ( dt_size && size )
+        *size = (paddr_t) (*dt_size);
+
+    return 0;
+}
+
 /*
  * Quirk for platforms where device tree incorrectly reports 4K GICC
  * size, but actually the two GICC register ranges are placed at 64K
-- 
2.17.1