diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 8457c754ed0..98715c90514 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2020-11-02  Andrew Burgess  <andrew.burgess@embecosm.com>
+	    Craig Blackmore   <craig.blackmore@embecosm.com>
+
+	* riscv-tdep.c (riscv_frame_cache): Read the frame base register
+	as an unsigned value.
+
 2020-11-01  Tom Tromey  <tom@tromey.com>
 
 	* dbxread.c (dbx_end_psymtab): Update.
diff --git a/gdb/riscv-tdep.c b/gdb/riscv-tdep.c
index 2c4eeab720b..e18f953eb13 100644
--- a/gdb/riscv-tdep.c
+++ b/gdb/riscv-tdep.c
@@ -2942,7 +2942,7 @@ riscv_frame_cache (struct frame_info *this_frame, void **this_cache)
 
   /* We can now calculate the frame base address.  */
   cache->frame_base
-    = (get_frame_register_signed (this_frame, cache->frame_base_reg)
+    = (get_frame_register_unsigned (this_frame, cache->frame_base_reg)
        + cache->frame_base_offset);
   if (riscv_debug_unwinder)
     fprintf_unfiltered (gdb_stdlog, "Frame base is %s ($%s + 0x%x)\n",