livepatch: resolve old address before function verification

When verifying that a livepatch can be applied, we may as well want to
inspect the target function to be patched. To do so, we need to resolve
this function's address before running the arch-specific
livepatch_verify hook.

Signed-off-by: Bjoern Doebel <doebel@amazon.de>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Ross Lagerwall <ross.lagerwall@citrix.com>
(cherry picked from commit 5142dc5c25)

xen/common/livepatch.c

@@ -685,11 +685,11 @@ static int prepare_payload(struct payload *payload,
                 return -EINVAL;
             }
 
-            rc = arch_livepatch_verify_func(f);
+            rc = resolve_old_address(f, elf);
             if ( rc )
                 return rc;
 
-            rc = resolve_old_address(f, elf);
+            rc = arch_livepatch_verify_func(f);
             if ( rc )
                 return rc;