diff --git a/arch/x86_64/src/intel64/intel64_head.S b/arch/x86_64/src/intel64/intel64_head.S
index 5792067c2c..764b8c3ca9 100644
--- a/arch/x86_64/src/intel64/intel64_head.S
+++ b/arch/x86_64/src/intel64/intel64_head.S
@@ -364,6 +364,10 @@ ap_start:
 	add     %rax, %rbx
 	mov     (%rbx),   %rsp
 
+	/* Move initial RSP below IDLE TCB regs */
+	sub     $XCPTCONTEXT_SIZE, %rsp
+	and     $(~XCPTCONTEXT_SIZE), %rsp
+
 	/* Jump to ap_start routine */
 	movabs  $x86_64_ap_boot,   %rbx
 	jmp     *%rbx