diff --git a/sys/cddl/dev/kinst/amd64/kinst_isa.h b/sys/cddl/dev/kinst/amd64/kinst_isa.h
--- a/sys/cddl/dev/kinst/amd64/kinst_isa.h
+++ b/sys/cddl/dev/kinst/amd64/kinst_isa.h
@@ -19,12 +19,8 @@
  */
 #define	KINST_TRAMP_SIZE	32
 #define	KINST_TRAMPCHUNK_SIZE	PAGE_SIZE
-
-/*
- * Fill the trampolines with breakpoint instructions so that the kernel will
- * crash cleanly if things somehow go wrong.
- */
-#define	KINST_TRAMP_INIT(t, s)	memset((t), KINST_PATCHVAL, (s))
+#define KINST_TRAMP_FILL	KINST_PATCHVAL
+#define KINST_TRAMP_FILL_SIZE	sizeof(uint8_t)
 
 typedef uint8_t kinst_patchval_t;
 
diff --git a/sys/cddl/dev/kinst/trampoline.c b/sys/cddl/dev/kinst/trampoline.c
--- a/sys/cddl/dev/kinst/trampoline.c
+++ b/sys/cddl/dev/kinst/trampoline.c
@@ -28,9 +28,6 @@
 #include "kinst.h"
 #include "kinst_isa.h"
 
-/*
- * We can have 4KB/32B = 128 trampolines per chunk.
- */
 #define KINST_TRAMPS_PER_CHUNK	(KINST_TRAMPCHUNK_SIZE / KINST_TRAMP_SIZE)
 
 struct trampchunk {
@@ -47,6 +44,20 @@
 static eventhandler_tag		kinst_thread_ctor_handler;
 static eventhandler_tag		kinst_thread_dtor_handler;
 
+/*
+ * Fill the trampolines with KINST_TRAMP_FILL so that the kernel will crash
+ * cleanly if things somehow go wrong.
+ */
+static void
+kinst_trampoline_fill(uint8_t *addr, int size)
+{
+	int i, v;
+
+	v = KINST_TRAMP_FILL;
+	for (i = 0; i < size; i += KINST_TRAMP_FILL_SIZE)
+		memcpy(&addr[i], &v, KINST_TRAMP_FILL_SIZE);
+}
+
 static struct trampchunk *
 kinst_trampchunk_alloc(void)
 {
@@ -77,7 +88,7 @@
 	    M_WAITOK | M_EXEC);
 	KASSERT(error == KERN_SUCCESS, ("kmem_back failed: %d", error));
 
-	KINST_TRAMP_INIT((void *)trampaddr, KINST_TRAMPCHUNK_SIZE);
+	kinst_trampoline_fill((uint8_t *)trampaddr, KINST_TRAMPCHUNK_SIZE);
 
 	/* Allocate a tracker for this chunk. */
 	chunk = malloc(sizeof(*chunk), M_KINST, M_WAITOK);
@@ -169,7 +180,7 @@
 	TAILQ_FOREACH(chunk, &kinst_trampchunks, next) {
 		for (off = 0; off < KINST_TRAMPS_PER_CHUNK; off++) {
 			if (chunk->addr + off * KINST_TRAMP_SIZE == tramp) {
-				KINST_TRAMP_INIT(tramp, KINST_TRAMP_SIZE);
+				kinst_trampoline_fill(tramp, KINST_TRAMP_SIZE);
 				BIT_SET(KINST_TRAMPS_PER_CHUNK, off,
 				    &chunk->free);
 				if (freechunks &&