1 files changed, 122 insertions, 0 deletions

diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
index 7fb1277ecacf..851f92a098de 100644
--- a/sys/amd64/amd64/pmap.c
+++ b/sys/amd64/amd64/pmap.c
@@ -4967,6 +4967,128 @@ out:
 }
 
 /*
+ *	Apply the given advice to the specified range of addresses within the
+ *	given pmap.  Depending on the advice, clear the referenced and/or
+ *	modified flags in each mapping and set the mapped page's dirty field.
+ */
+void
+pmap_advise(pmap_t pmap, vm_offset_t sva, vm_offset_t eva, int advice)
+{
+	struct rwlock *lock;
+	pml4_entry_t *pml4e;
+	pdp_entry_t *pdpe;
+	pd_entry_t oldpde, *pde;
+	pt_entry_t *pte;
+	vm_offset_t va_next;
+	vm_page_t m;
+	boolean_t anychanged, pv_lists_locked;
+
+	if (advice != MADV_DONTNEED && advice != MADV_FREE)
+		return;
+	pv_lists_locked = FALSE;
+resume:
+	anychanged = FALSE;
+	PMAP_LOCK(pmap);
+	for (; sva < eva; sva = va_next) {
+		pml4e = pmap_pml4e(pmap, sva);
+		if ((*pml4e & PG_V) == 0) {
+			va_next = (sva + NBPML4) & ~PML4MASK;
+			if (va_next < sva)
+				va_next = eva;
+			continue;
+		}
+		pdpe = pmap_pml4e_to_pdpe(pml4e, sva);
+		if ((*pdpe & PG_V) == 0) {
+			va_next = (sva + NBPDP) & ~PDPMASK;
+			if (va_next < sva)
+				va_next = eva;
+			continue;
+		}
+		va_next = (sva + NBPDR) & ~PDRMASK;
+		if (va_next < sva)
+			va_next = eva;
+		pde = pmap_pdpe_to_pde(pdpe, sva);
+		oldpde = *pde;
+		if ((oldpde & PG_V) == 0)
+			continue;
+		else if ((oldpde & PG_PS) != 0) {
+			if ((oldpde & PG_MANAGED) == 0)
+				continue;
+			if (!pv_lists_locked) {
+				pv_lists_locked = TRUE;
+				if (!rw_try_rlock(&pvh_global_lock)) {
+					if (anychanged)
+						pmap_invalidate_all(pmap);
+					PMAP_UNLOCK(pmap);
+					rw_rlock(&pvh_global_lock);
+					goto resume;
+				}
+			}
+			lock = NULL;
+			if (!pmap_demote_pde_locked(pmap, pde, sva, &lock)) {
+				if (lock != NULL)
+					rw_wunlock(lock);
+
+				/*
+				 * The large page mapping was destroyed.
+				 */
+				continue;
+			}
+
+			/*
+			 * Unless the page mappings are wired, remove the
+			 * mapping to a single page so that a subsequent
+			 * access may repromote.  Since the underlying page
+			 * table page is fully populated, this removal never
+			 * frees a page table page.
+			 */
+			if ((oldpde & PG_W) == 0) {
+				pte = pmap_pde_to_pte(pde, sva);
+				KASSERT((*pte & PG_V) != 0,
+				    ("pmap_advise: invalid PTE"));
+				pmap_remove_pte(pmap, pte, sva, *pde, NULL,
+				    &lock);
+				anychanged = TRUE;
+			}
+			if (lock != NULL)
+				rw_wunlock(lock);
+		}
+		if (va_next > eva)
+			va_next = eva;
+		for (pte = pmap_pde_to_pte(pde, sva); sva != va_next; pte++,
+		    sva += PAGE_SIZE) {
+			if ((*pte & (PG_MANAGED | PG_V)) != (PG_MANAGED |
+			    PG_V))
+				continue;
+			else if ((*pte & (PG_M | PG_RW)) == (PG_M | PG_RW)) {
+				if (advice == MADV_DONTNEED) {
+					/*
+					 * Future calls to pmap_is_modified()
+					 * can be avoided by making the page
+					 * dirty now.
+					 */
+					m = PHYS_TO_VM_PAGE(*pte & PG_FRAME);
+					vm_page_dirty(m);
+				}
+				atomic_clear_long(pte, PG_M | PG_A);
+			} else if ((*pte & PG_A) != 0)
+				atomic_clear_long(pte, PG_A);
+			else
+				continue;
+			if ((*pte & PG_G) != 0)
+				pmap_invalidate_page(pmap, sva);
+			else
+				anychanged = TRUE;
+		}
+	}
+	if (anychanged)
+		pmap_invalidate_all(pmap);
+	if (pv_lists_locked)
+		rw_runlock(&pvh_global_lock);
+	PMAP_UNLOCK(pmap);
+}
+
+/*
  *	Clear the modify bits on the specified physical page.
  */
 void