amd64 pmap: More unification for psind = 1 vs 2 in pmap_enter_largepage().

Move
  pkru check
  wait for page alloc
  wire accounting update
  asserting allowed updates for valid mappings
out of psind conditions.

Also add assert that psind references supported page size.
Remove not true comment.
Avoid uneccessary page table walks from top level.

Reviewed by:	alc, markj (previous version)
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D26513

1 files changed, 28 insertions, 49 deletions

diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
index 80c665da24d7..68cdfba155c9 100644
--- a/sys/amd64/amd64/pmap.c
+++ b/sys/amd64/amd64/pmap.c
@@ -6479,7 +6479,7 @@ pmap_enter_largepage(pmap_t pmap, vm_offset_t va, pt_entry_t newpte, int flags,
 	pt_entry_t origpte, *pml4e, *pdpe, *pde, pten, PG_V;
 
 	PMAP_LOCK_ASSERT(pmap, MA_OWNED);
-	KASSERT(psind > 0 && psind < MAXPAGESIZES,
+	KASSERT(psind > 0 && psind < MAXPAGESIZES && pagesizes[psind] != 0,
 	    ("psind %d unexpected", psind));
 	KASSERT(((newpte & PG_FRAME) & (pagesizes[psind] - 1)) == 0,
 	    ("unaligned phys address %#lx newpte %#lx psind %d",
@@ -6494,38 +6494,25 @@ pmap_enter_largepage(pmap_t pmap, vm_offset_t va, pt_entry_t newpte, int flags,
 	PG_V = pmap_valid_bit(pmap);
 
 restart:
+	if (!pmap_pkru_same(pmap, va, va + pagesizes[psind]))
+		return (KERN_PROTECTION_FAILURE);
 	pten = newpte;
 	if (va < VM_MAXUSER_ADDRESS && pmap->pm_type == PT_X86)
 		pten |= pmap_pkru_get(pmap, va);
 
 	if (psind == 2) {	/* 1G */
-		if (!pmap_pkru_same(pmap, va, va + NBPDP))
-			return (KERN_PROTECTION_FAILURE);
 		pml4e = pmap_pml4e(pmap, va);
 		if (pml4e == NULL || (*pml4e & PG_V) == 0) {
 			mp = _pmap_allocpte(pmap, pmap_pml4e_pindex(va),
 			    NULL, va);
-			if (mp == NULL) {
-				if ((flags & PMAP_ENTER_NOSLEEP) != 0)
-					return (KERN_RESOURCE_SHORTAGE);
-				PMAP_UNLOCK(pmap);
-				vm_wait(NULL);
-				PMAP_LOCK(pmap);
-
-				/*
-				 * Restart at least to recalcuate the pkru
-				 * key.  Our caller must keep the map locked
-				 * so no paging structure can be validated
-				 * under us.
-				 */
-				goto restart;
-			}
-			pdpe = pmap_pdpe(pmap, va);
-			KASSERT(pdpe != NULL, ("va %#lx lost pdpe", va));
+			if (mp == NULL)
+				goto allocf;
+			pdpe = (pdp_entry_t *)PHYS_TO_DMAP(VM_PAGE_TO_PHYS(mp));
+			pdpe = &pdpe[pmap_pdpe_index(va)];
 			origpte = *pdpe;
 			MPASS(origpte == 0);
 		} else {
-			pdpe = pmap_pdpe(pmap, va);
+			pdpe = pmap_pml4e_to_pdpe(pml4e, va);
 			KASSERT(pdpe != NULL, ("va %#lx lost pdpe", va));
 			origpte = *pdpe;
 			if ((origpte & PG_V) == 0) {
@@ -6533,57 +6520,49 @@ restart:
 				mp->ref_count++;
 			}
 		}
-		KASSERT((origpte & PG_V) == 0 || ((origpte & PG_PS) != 0 &&
-		    (origpte & PG_FRAME) == (pten & PG_FRAME)),
-		    ("va %#lx changing 1G phys page pdpe %#lx pten %#lx",
-		    va, origpte, pten));
-		if ((pten & PG_W) != 0 && (origpte & PG_W) == 0)
-			pmap->pm_stats.wired_count += NBPDP / PAGE_SIZE;
-		else if ((pten & PG_W) == 0 && (origpte & PG_W) != 0)
-			pmap->pm_stats.wired_count -= NBPDP / PAGE_SIZE;
 		*pdpe = pten;
 	} else /* (psind == 1) */ {	/* 2M */
-		if (!pmap_pkru_same(pmap, va, va + NBPDR))
-			return (KERN_PROTECTION_FAILURE);
 		pde = pmap_pde(pmap, va);
 		if (pde == NULL) {
 			mp = _pmap_allocpte(pmap, pmap_pdpe_pindex(va),
 			    NULL, va);
-			if (mp == NULL) {
-				if ((flags & PMAP_ENTER_NOSLEEP) != 0)
-					return (KERN_RESOURCE_SHORTAGE);
-				PMAP_UNLOCK(pmap);
-				vm_wait(NULL);
-				PMAP_LOCK(pmap);
-				goto restart;
-			}
+			if (mp == NULL)
+				goto allocf;
 			pde = (pd_entry_t *)PHYS_TO_DMAP(VM_PAGE_TO_PHYS(mp));
 			pde = &pde[pmap_pde_index(va)];
 			origpte = *pde;
 			MPASS(origpte == 0);
 		} else {
-			pdpe = pmap_pdpe(pmap, va);
-			MPASS(pdpe != NULL && (*pdpe & PG_V) != 0);
 			origpte = *pde;
 			if ((origpte & PG_V) == 0) {
+				pdpe = pmap_pdpe(pmap, va);
+				MPASS(pdpe != NULL && (*pdpe & PG_V) != 0);
 				mp = PHYS_TO_VM_PAGE(*pdpe & PG_FRAME);
 				mp->ref_count++;
 			}
 		}
-		KASSERT((origpte & PG_V) == 0 || ((origpte & PG_PS) != 0 &&
-		    (origpte & PG_FRAME) == (pten & PG_FRAME)),
-		    ("va %#lx changing 2M phys page pde %#lx pten %#lx",
-		    va, origpte, pten));
-		if ((pten & PG_W) != 0 && (origpte & PG_W) == 0)
-			pmap->pm_stats.wired_count += NBPDR / PAGE_SIZE;
-		else if ((pten & PG_W) == 0 && (origpte & PG_W) != 0)
-			pmap->pm_stats.wired_count -= NBPDR / PAGE_SIZE;
 		*pde = pten;
 	}
+	KASSERT((origpte & PG_V) == 0 || ((origpte & PG_PS) != 0 &&
+	    (origpte & PG_PS_FRAME) == (pten & PG_PS_FRAME)),
+	    ("va %#lx changing %s phys page origpte %#lx pten %#lx",
+	    va, psind == 2 ? "1G" : "2M", origpte, pten));
+	if ((pten & PG_W) != 0 && (origpte & PG_W) == 0)
+		pmap->pm_stats.wired_count += pagesizes[psind] / PAGE_SIZE;
+	else if ((pten & PG_W) == 0 && (origpte & PG_W) != 0)
+		pmap->pm_stats.wired_count -= pagesizes[psind] / PAGE_SIZE;
 	if ((origpte & PG_V) == 0)
 		pmap_resident_count_inc(pmap, pagesizes[psind] / PAGE_SIZE);
 
 	return (KERN_SUCCESS);
+
+allocf:
+	if ((flags & PMAP_ENTER_NOSLEEP) != 0)
+		return (KERN_RESOURCE_SHORTAGE);
+	PMAP_UNLOCK(pmap);
+	vm_wait(NULL);
+	PMAP_LOCK(pmap);
+	goto restart;
 }
 
 /*