diff --git a/arch/x86/core/intel64/cpu.c b/arch/x86/core/intel64/cpu.c
index 36c4d8657e6..b7222828b60 100644
--- a/arch/x86/core/intel64/cpu.c
+++ b/arch/x86/core/intel64/cpu.c
@@ -86,7 +86,8 @@ struct x86_cpuboot x86_cpuboot[] = {
 	{
 		.tr = X86_KERNEL_CPU0_TR,
 		.gs_base = &tss0,
-		.sp = (u64_t) z_interrupt_stacks[0] + CONFIG_ISR_STACK_SIZE,
+		.sp = (u64_t) (z_interrupt_stacks[0] + CONFIG_ISR_STACK_SIZE +
+			       ARCH_THREAD_STACK_RESERVED),
 		.fn = z_x86_prep_c,
 #ifdef CONFIG_X86_MMU
 		.ptables = &z_x86_flat_ptables,