Function pmap_update_pde_invalidate

freebsd/amd64/amd64/pmap.c:2668–2697

* After changing the page size for the specified virtual address in the page * table, flush the corresponding entries from the processor's TLB. Only the * calling processor's TLB is affected. * * The calling thread must be pinned to a processor. */

 * The calling thread must be pinned to a processor.
 */
static void
pmap_update_pde_invalidate(pmap_t pmap, vm_offset_t va, pd_entry_t newpde)
{
	pt_entry_t PG_G;

	if (pmap_type_guest(pmap))
		return;

	KASSERT(pmap->pm_type == PT_X86,
	    ("pmap_update_pde_invalidate: invalid type %d", pmap->pm_type));

	PG_G = pmap_global_bit(pmap);

	if ((newpde & PG_PS) == 0)
		/* Demotion: flush a specific 2MB page mapping. */
		invlpg(va);
	else if ((newpde & PG_G) == 0)
		/*
		 * Promotion: flush every 4KB page mapping from the TLB
		 * because there are too many to flush individually.
		 */
		invltlb();
	else {
		/*
		 * Promotion: flush every 4KB page mapping from the TLB,
		 * including any global (PG_G) mappings.
		 */
		invltlb_glob();
	}
}

/*
 * The amd64 pmap uses different approaches to TLB invalidation