diff --git a/gdb/target.c b/gdb/target.c
index 151209e..91b4b47 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -1756,7 +1756,7 @@ target_xfer_partial (struct target_ops *ops,
    it makes no progress, and then return how much was transferred).  */
 
 int
-target_read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, int len)
+target_read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, size_t len)
 {
   /* Dispatch to the topmost target, not the flattened current_target.
      Memory accesses check target->to_has_(all_)memory, and the
diff --git a/gdb/target.h b/gdb/target.h
index f80fba0..f3ef33a 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -996,7 +996,8 @@ extern void target_dcache_invalidate (void);
 
 extern int target_read_string (CORE_ADDR, char **, int, int *);
 
-extern int target_read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, int len);
+extern int target_read_memory (CORE_ADDR memaddr, gdb_byte *myaddr,
+			       size_t len);
 
 extern int target_read_stack (CORE_ADDR memaddr, gdb_byte *myaddr, int len);
 
-- 
1.7.7.6