comboot: fix memory overwrite bug

Fix memory overwrite bug, specifically, the use of BP after it might
have gotten clobbered.  Since at the point of use, BP is supposed to
be == SP, we can just add "mov bp,sp".

diff --git a/comboot.inc b/comboot.inc
index 3c9df5f..ffc9425 100644 (file)
--- a/comboot.inc
+++ b/comboot.inc
@@ -187,6 +187,7 @@ comboot_int21:      cli
                clc
                call ax                 ; Call the invoked function
 comboot_resume:
+               mov bp,sp               ; In case the function clobbers BP
                setc P_FLAGSL           ; Propagate CF->error
                popad
                pop gs