diff --git a/racket/src/racket/sconfig.h b/racket/src/racket/sconfig.h
index 07ec0c1b67..404e9978ad 100644
--- a/racket/src/racket/sconfig.h
+++ b/racket/src/racket/sconfig.h
@@ -212,6 +212,7 @@
 
 # if defined(__x86_64__)
 #  define SCHEME_PLATFORM_LIBRARY_SUBPATH "x86_64-openbsd"
+#  define IMPLEMENT_WRITE_XOR_EXECUTE_BY_SIGNAL_HANDLER
 # elif defined(__i386__) || defined(i386)
 #  define SCHEME_PLATFORM_LIBRARY_SUBPATH "i386-openbsd"
 # elif defined(__mips64__)
@@ -249,7 +250,6 @@
 # define USE_IEEE_FP_PREDS
 
 # define USE_MAP_ANON
-# define IMPLEMENT_WRITE_XOR_EXECUTE_BY_SIGNAL_HANDLER
 
 # if defined(__x86_64__)
 #  define MZ_USE_JIT_X86_64
diff --git a/racket/src/racket/src/salloc.c b/racket/src/racket/src/salloc.c
index 7b0c7a0439..38cfc74bb2 100644
--- a/racket/src/racket/src/salloc.c
+++ b/racket/src/racket/src/salloc.c
@@ -110,6 +110,11 @@ static void init_allocation_callback(void);
 #endif
 
 #ifdef IMPLEMENT_WRITE_XOR_EXECUTE_BY_SIGNAL_HANDLER
+/* For this option to work, the `si->si_addr` value provided
+   to the signal handler on a no-execute-permission signal
+   must be the address that isn't executable, as opposed to
+   the address of an instruction that tried to call or jump to
+   a non-executable address. */
 static void install_w_xor_x_handler();
 static void register_as_executable(void *p, size_t len, int can_exec);
 #endif