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
@@ -17,14 +17,10 @@
  * have 2 instructions stored in the trampoline, and each of them can take up
  * to 16 bytes, 32 bytes is enough to cover even the worst case scenario.
  */
-#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_SIZE		32
+#define	KINST_TRAMPCHUNK_SIZE		PAGE_SIZE
+#define KINST_TRAMP_FILL_PATTERN	((uint8_t []){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 +44,21 @@
 static eventhandler_tag		kinst_thread_ctor_handler;
 static eventhandler_tag		kinst_thread_dtor_handler;
 
+/*
+ * Fill the trampolines with KINST_TRAMP_FILL_PATTERN so that the kernel will
+ * crash cleanly if things somehow go wrong.
+ */
+static void
+kinst_trampoline_fill(uint8_t *addr, int size)
+{
+	int i;
+
+	for (i = 0; i < size; i += KINST_TRAMP_FILL_SIZE) {
+		memcpy(&addr[i], KINST_TRAMP_FILL_PATTERN,
+		    KINST_TRAMP_FILL_SIZE);
+	}
+}
+
 static struct trampchunk *
 kinst_trampchunk_alloc(void)
 {
@@ -77,7 +89,7 @@
 	    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);
@@ -171,7 +183,7 @@
 	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 &&