[Xen-devel] [RFC for-4.8 v2 7/7] xen/arm: Map mmio-sram nodes as normal un-cached rwx memory

["Edgar E. Iglesias" <edgar.iglesias@xxxxxxxxx>]

From: "Edgar E. Iglesias" <edgar.iglesias@xxxxxxxxxx>

Map mmio-sram nodes as normal un-cached MEMORY with RWX perms.
If the node has set the no-memory-wc property, we map it as
DEVICE RW.

Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xxxxxxxxxx>
---
 xen/arch/arm/domain_build.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 064feb3..2a2316b 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -54,6 +54,32 @@ struct map_range_data
     const struct map_attr *attr;
 };
 
+static const struct map_attr mattr_device_rw __initconst =
+{
+    .memattr = MATTR_DEV,
+    .access = p2m_access_rw,
+};
+
+static const struct map_attr mattr_memory_nc_rwx __initconst =
+{
+    .memattr = MATTR_MEM_NC,
+    .access = p2m_access_rwx,
+};
+
+static const struct dt_device_match dev_map_attrs[] __initconst =
+{
+    {
+        __DT_MATCH_COMPATIBLE("mmio-sram"),
+        __DT_MATCH_PROPS("no-memory-wc"),
+        .data = &mattr_device_rw,
+    },
+    {
+        __DT_MATCH_COMPATIBLE("mmio-sram"),
+        .data = &mattr_memory_nc_rwx,
+    },
+    { /* sentinel */ },
+};
+
 //#define DEBUG_DT
 
 #ifdef DEBUG_DT
@@ -1201,6 +1227,16 @@ static int handle_device(struct domain *d, struct 
dt_device_node *dev,
     return 0;
 }
 
+static const struct map_attr *lookup_map_attr(struct dt_device_node *node,
+                                            const struct map_attr *parent_attr)
+{
+    const struct dt_device_match *r;
+
+    /* Search and if nothing matches, use the parent's attributes.  */
+    r = dt_match_node(dev_map_attrs, node);
+    return r ? r->data : parent_attr;
+}
+
 static int handle_node(struct domain *d, struct kernel_info *kinfo,
                        struct dt_device_node *node,
                        const struct map_attr *attr)
@@ -1290,6 +1326,7 @@ static int handle_node(struct domain *d, struct 
kernel_info *kinfo,
                "WARNING: Path %s is reserved, skip the node as we may re-use 
the path.\n",
                path);
 
+    attr = lookup_map_attr(node, attr);
     res = handle_device(d, node, attr);
     if ( res)
         return res;
-- 
2.5.0


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