[PATCH v2 4/7] xen/device-tree: Fix bootfdt.c to tolerate 0 reserved regions

[Shawn Anastasio]

The early_print_info routine in bootfdt.c incorrectly stores the result
of a call to fdt_num_mem_rsv() in an unsigned int, which results in the
negative error code being interpreted incorrectly in a subsequent loop
in the case where the device tree does not contain any memory reserve
map entries.

Signed-off-by: Shawn Anastasio <sanasta...@raptorengineering.com>
---
 xen/common/device-tree/bootfdt.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/xen/common/device-tree/bootfdt.c b/xen/common/device-tree/bootfdt.c
index ae9fa1e3d6..796ac01c18 100644
--- a/xen/common/device-tree/bootfdt.c
+++ b/xen/common/device-tree/bootfdt.c
@@ -466,7 +466,8 @@ static void __init early_print_info(void)
     struct meminfo *mem_resv = &bootinfo.reserved_mem;
     struct bootmodules *mods = &bootinfo.modules;
     struct bootcmdlines *cmds = &bootinfo.cmdlines;
-    unsigned int i, j, nr_rsvd;
+    unsigned int i, j;
+    int nr_rsvd;
 
     for ( i = 0; i < mi->nr_banks; i++ )
         printk("RAM: %"PRIpaddr" - %"PRIpaddr"\n",
@@ -481,7 +482,7 @@ static void __init early_print_info(void)
                 boot_module_kind_as_string(mods->module[i].kind));
 
     nr_rsvd = fdt_num_mem_rsv(device_tree_flattened);
-    for ( i = 0; i < nr_rsvd; i++ )
+    for ( i = 0; nr_rsvd > 0 && i < nr_rsvd; i++ )
     {
         paddr_t s, e;
 
-- 
2.30.2