Function pmap_remove_pages

freebsd/arm64/arm64/pmap.c:5087–5252

* Destroy all managed, non-wired mappings in the given user-space * pmap. This pmap cannot be active on any processor besides the * caller. * * This function cannot be applied to the kernel pmap. Moreover, it * is not intended for general use. It is only to be used during * process termination. Consequently, it can be implemented in ways * that make it faster than pmap_remove(). First,

 * this function starts.
 */
void
pmap_remove_pages(pmap_t pmap)
{
	pd_entry_t *pde;
	pt_entry_t *pte, tpte;
	struct spglist free;
	vm_page_t m, ml3, mt;
	pv_entry_t pv;
	struct md_page *pvh;
	struct pv_chunk *pc, *npc;
	struct rwlock *lock;
	int64_t bit;
	uint64_t inuse, bitmask;
	int allfree, field, freed, idx, lvl;
	vm_paddr_t pa;

	lock = NULL;

	SLIST_INIT(&free);
	PMAP_LOCK(pmap);
	TAILQ_FOREACH_SAFE(pc, &pmap->pm_pvchunk, pc_list, npc) {
		allfree = 1;
		freed = 0;
		for (field = 0; field < _NPCM; field++) {
			inuse = ~pc->pc_map[field] & pc_freemask[field];
			while (inuse != 0) {
				bit = ffsl(inuse) - 1;
				bitmask = 1UL << bit;
				idx = field * 64 + bit;
				pv = &pc->pc_pventry[idx];
				inuse &= ~bitmask;

				pde = pmap_pde(pmap, pv->pv_va, &lvl);
				KASSERT(pde != NULL,
				    ("Attempting to remove an unmapped page"));

				switch(lvl) {
				case 1:
					pte = pmap_l1_to_l2(pde, pv->pv_va);
					tpte = pmap_load(pte); 
					KASSERT((tpte & ATTR_DESCR_MASK) ==
					    L2_BLOCK,
					    ("Attempting to remove an invalid "
					    "block: %lx", tpte));
					break;
				case 2:
					pte = pmap_l2_to_l3(pde, pv->pv_va);
					tpte = pmap_load(pte);
					KASSERT((tpte & ATTR_DESCR_MASK) ==
					    L3_PAGE,
					    ("Attempting to remove an invalid "
					     "page: %lx", tpte));
					break;
				default:
					panic(
					    "Invalid page directory level: %d",
					    lvl);
				}