MCE_STACK_SIZE
static char mce0_stack[MCE_STACK_SIZE] __aligned(16);
np = ((struct nmi_pcpu *)&mce_stack[MCE_STACK_SIZE]) - 1;
mce_stack = kmem_malloc(MCE_STACK_SIZE,
pmap_pti_add_kva_locked(va - MCE_STACK_SIZE, va, false);