[RFC 04/24] xen/dts: Constify device_tree_flattened

[Julien Grall <julien.grall@linaro.org>]

The Flat Device Tree is given by the bootloader. Xen doesn't need to modify it.

Signed-off-by: Julien Grall <julien.grall@linaro.org>
---
 xen/arch/arm/domain_build.c   |    2 +-
 xen/arch/arm/setup.c          |    6 ++++--
 xen/common/device_tree.c      |    2 +-
 xen/include/xen/device_tree.h |    2 +-
 4 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 01492bb..a324c3b 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -475,7 +475,7 @@ static int map_devices_from_device_tree(struct domain *d)
 
 static int prepare_dtb(struct domain *d, struct kernel_info *kinfo)
 {
-    void *fdt;
+    const void *fdt;
     int new_size;
     int ret;
     paddr_t end;
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 1ec5e38..c9534fd 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -289,6 +289,7 @@ static void __init setup_mm(unsigned long dtb_paddr, size_t dtb_size)
     unsigned long dtb_pages;
     unsigned long boot_mfn_start, boot_mfn_end;
     int i = 0;
+    void *fdt;
 
     /* TODO: Handle non-contiguous memory bank */
     if ( !early_info.mem.nr_banks )
@@ -363,8 +364,9 @@ static void __init setup_mm(unsigned long dtb_paddr, size_t dtb_size)
      *
      * TODO: handle other payloads too.
      */
-    device_tree_flattened = mfn_to_virt(alloc_boot_pages(dtb_pages, 1));
-    copy_from_paddr(device_tree_flattened, dtb_paddr, dtb_size, BUFFERABLE);
+    fdt = mfn_to_virt(alloc_boot_pages(dtb_pages, 1));
+    copy_from_paddr(fdt, dtb_paddr, dtb_size, BUFFERABLE);
+    device_tree_flattened = fdt;
 
     /* Add non-xenheap memory */
     s = ram_start;
diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
index 51f23eb..b96ae33 100644
--- a/xen/common/device_tree.c
+++ b/xen/common/device_tree.c
@@ -26,7 +26,7 @@
 #include <asm/early_printk.h>
 
 struct dt_early_info __initdata early_info;
-void *device_tree_flattened;
+const void *device_tree_flattened;
 dt_irq_xlate_func dt_irq_xlate;
 /* Host device tree */
 struct dt_device_node *dt_host;
diff --git a/xen/include/xen/device_tree.h b/xen/include/xen/device_tree.h
index 5a2a5c6..7cd9e19 100644
--- a/xen/include/xen/device_tree.h
+++ b/xen/include/xen/device_tree.h
@@ -158,7 +158,7 @@ typedef int (*device_tree_node_func)(const void *fdt,
                                      void *data);
 
 extern struct dt_early_info early_info;
-extern void *device_tree_flattened;
+extern const void *device_tree_flattened;
 
 size_t __init device_tree_early_init(const void *fdt);
 
-- 
1.7.10.4