Stop using PVF_MOD, PVF_REF & PVF_EXEC flags in pv_entry, use PTE.

Using PVF_MOD, PVF_REF and PVF_EXEC is redundant as we can get the proper
info from PTE bits.
When the mapping is marked as executable and has been referenced we assume
that it has been executed. Similarly, when the mapping is set to be writable
and is referenced, it must have been due to write access to it.
PVF_MOD and PVF_REF flags are kept just for pmap_clearbit() usage,
to pass the information on which bit should be cleared.

Submitted by:   Zbigniew Bodek <zbb@semihalf.com>
Sponsored by:   The FreeBSD Foundation, Semihalf

2 files changed, 33 insertions, 36 deletions

diff --git a/sys/arm/arm/pmap-v6.c b/sys/arm/arm/pmap-v6.c
index 4651aed..cd98395 100644
--- a/sys/arm/arm/pmap-v6.c
+++ b/sys/arm/arm/pmap-v6.c
@@ -383,13 +383,13 @@ int	pmap_needs_pte_sync;
  * Macro to determine if a mapping might be resident in the
  * instruction cache and/or TLB
  */
-#define	PV_BEEN_EXECD(f)  (((f) & (PVF_REF | PVF_EXEC)) == (PVF_REF | PVF_EXEC))
+#define	PTE_BEEN_EXECD(pte)  (L2_S_EXECUTABLE(pte) && L2_S_REFERENCED(pte))
 
 /*
  * Macro to determine if a mapping might be resident in the
  * data cache and/or TLB
  */
-#define	PV_BEEN_REFD(f)   (((f) & PVF_REF) != 0)
+#define	PTE_BEEN_REFD(pte)   (L2_S_REFERENCED(pte))
 
 #ifndef PMAP_SHPGPERPROC
 #define PMAP_SHPGPERPROC 200
@@ -947,9 +947,9 @@ pmap_clearbit(struct vm_page *m, u_int maskbits)
 			*ptep = npte;
 			PTE_SYNC(ptep);
 			/* Flush the TLB entry if a current pmap. */
-			if (PV_BEEN_EXECD(oflags))
+			if (PTE_BEEN_EXECD(opte))
 				cpu_tlb_flushID_SE(pv->pv_va);
-			else if (PV_BEEN_REFD(oflags))
+			else if (PTE_BEEN_REFD(opte))
 				cpu_tlb_flushD_SE(pv->pv_va);
 		}
 
@@ -1358,7 +1358,6 @@ pmap_fault_fixup(pmap_t pmap, vm_offset_t va, vm_prot_t ftype, int user)
 		}
 
 		vm_page_dirty(m);
-		pv->pv_flags |= PVF_REF | PVF_MOD;
 
 		/* Re-enable write permissions for the page */
 		pmap_set_prot(ptep, VM_PROT_WRITE, *ptep & L2_S_PROT_U);
@@ -1382,7 +1381,6 @@ pmap_fault_fixup(pmap_t pmap, vm_offset_t va, vm_prot_t ftype, int user)
 			goto out;
 
 		vm_page_aflag_set(m, PGA_REFERENCED);
-		pv->pv_flags |= PVF_REF;
 
 		/* Mark the page "referenced" */
 		*ptep = pte | L2_S_REF;
@@ -2436,7 +2434,7 @@ pmap_remove_all(vm_page_t m)
 	struct l2_bucket *l2b;
 	boolean_t flush = FALSE;
 	pmap_t curpmap;
-	int flags = 0;
+	u_int is_exec = 0;
 
 	KASSERT((m->flags & PG_FICTITIOUS) == 0,
 	    ("pmap_remove_all: page %p is fictitious", m));
@@ -2455,19 +2453,19 @@ pmap_remove_all(vm_page_t m)
 		l2b = pmap_get_l2_bucket(pmap, pv->pv_va);
 		KASSERT(l2b != NULL, ("No l2 bucket"));
 		ptep = &l2b->l2b_kva[l2pte_index(pv->pv_va)];
+		is_exec |= PTE_BEEN_EXECD(*ptep);
 		*ptep = 0;
 		if (pmap_is_current(pmap))
 			PTE_SYNC(ptep);
 		pmap_free_l2_bucket(pmap, l2b, 1);
 		pmap->pm_stats.resident_count--;
-		flags |= pv->pv_flags;
 		pmap_nuke_pv(m, pmap, pv);
 		pmap_free_pv_entry(pmap, pv);
 		PMAP_UNLOCK(pmap);
 	}
 
 	if (flush) {
-		if (PV_BEEN_EXECD(flags))
+		if (is_exec)
 			cpu_tlb_flushID();
 		else
 			cpu_tlb_flushD();
@@ -2545,7 +2543,7 @@ pmap_protect(pmap_t pmap, vm_offset_t sva, vm_offset_t eva, vm_prot_t prot)
 	struct l2_bucket *l2b;
 	pt_entry_t *ptep, pte;
 	vm_offset_t next_bucket;
-	u_int flags;
+	u_int is_exec, is_refd;
 	int flush;
 
 	if ((prot & VM_PROT_READ) == 0) {
@@ -2570,7 +2568,7 @@ pmap_protect(pmap_t pmap, vm_offset_t sva, vm_offset_t eva, vm_prot_t prot)
 	 */
 
 	flush = ((eva - sva) >= (PAGE_SIZE * 4)) ? 0 : -1;
-	flags = 0;
+	is_exec = is_refd = 0;
 
 	while (sva < eva) {
 		next_bucket = L2_NEXT_BUCKET(sva);
@@ -2588,25 +2586,24 @@ pmap_protect(pmap_t pmap, vm_offset_t sva, vm_offset_t eva, vm_prot_t prot)
 		while (sva < next_bucket) {
 			if ((pte = *ptep) != 0 && L2_S_WRITABLE(pte)) {
 				struct vm_page *m;
-				u_int f;
 
 				m = PHYS_TO_VM_PAGE(l2pte_pa(pte));
 				pmap_set_prot(ptep, prot,
 				    !(pmap == pmap_kernel()));
 				PTE_SYNC(ptep);
 
-				f = pmap_modify_pv(m, pmap, sva,
-				    PVF_WRITE, 0);
+				pmap_modify_pv(m, pmap, sva, PVF_WRITE, 0);
 
 				if (flush >= 0) {
 					flush++;
-					flags |= f;
-				} else
-				if (PV_BEEN_EXECD(f))
-					cpu_tlb_flushID_SE(sva);
-				else
-				if (PV_BEEN_REFD(f))
-					cpu_tlb_flushD_SE(sva);
+					is_exec |= PTE_BEEN_EXECD(pte);
+					is_refd |= PTE_BEEN_REFD(pte);
+				} else {
+					if (PTE_BEEN_EXECD(pte))
+						cpu_tlb_flushID_SE(sva);
+					else if (PTE_BEEN_REFD(pte))
+						cpu_tlb_flushD_SE(sva);
+				}
 			}
 
 			sva += PAGE_SIZE;
@@ -2616,10 +2613,10 @@ pmap_protect(pmap_t pmap, vm_offset_t sva, vm_offset_t eva, vm_prot_t prot)
 
 
 	if (flush) {
-		if (PV_BEEN_EXECD(flags))
+		if (is_exec)
 			cpu_tlb_flushID();
 		else
-		if (PV_BEEN_REFD(flags))
+		if (is_refd)
 			cpu_tlb_flushD();
 	}
 	rw_wunlock(&pvh_global_lock);
@@ -2665,7 +2662,7 @@ pmap_enter_locked(pmap_t pmap, vm_offset_t va, vm_prot_t access, vm_page_t m,
 	struct pv_entry *pve = NULL;
 	pt_entry_t *ptep, npte, opte;
 	u_int nflags;
-	u_int oflags;
+	u_int is_exec, is_refd;
 	vm_paddr_t pa;
 	u_char user;
 
@@ -2692,8 +2689,6 @@ pmap_enter_locked(pmap_t pmap, vm_offset_t va, vm_prot_t access, vm_page_t m,
 
 	if (prot & VM_PROT_WRITE)
 		nflags |= PVF_WRITE;
-	if (prot & VM_PROT_EXECUTE)
-		nflags |= PVF_EXEC;
 	if (wired)
 		nflags |= PVF_WIRED;
 
@@ -2725,7 +2720,8 @@ do_l2b_alloc:
 
 	opte = *ptep;
 	npte = pa;
-	oflags = 0;
+	is_exec = is_refd = 0;
+
 	if (opte) {
 		/*
 		 * There is already a mapping at this address.
@@ -2748,7 +2744,6 @@ do_l2b_alloc:
 		 *   so no need to re-do referenced emulation here.
 		 */
 		npte |= L2_S_REF;
-		nflags |= PVF_REF;
 
 		if (m != NULL &&
 		    (m->oflags & VPO_UNMANAGED) == 0)
@@ -2799,9 +2794,9 @@ do_l2b_alloc:
 		/*
 		 * We're changing the attrs of an existing mapping.
 		 */
-		oflags = pmap_modify_pv(m, pmap, va,
-		    PVF_WRITE | PVF_EXEC | PVF_WIRED |
-		    PVF_MOD | PVF_REF, nflags);
+		pmap_modify_pv(m, pmap, va, PVF_WRITE | PVF_WIRED, nflags);
+		is_exec |= PTE_BEEN_EXECD(opte);
+		is_refd |= PTE_BEEN_REFD(opte);
 	} else {
 		/*
 		 * New mapping, or changing the backing page
@@ -2814,7 +2809,8 @@ do_l2b_alloc:
 			 * must remove it from the PV list
 			 */
 			if ((pve = pmap_remove_pv(om, pmap, va))) {
-			    oflags = pve->pv_flags;
+				is_exec |= PTE_BEEN_EXECD(opte);
+				is_refd |= PTE_BEEN_REFD(opte);
 
 			    if (m && ((m->oflags & VPO_UNMANAGED)))
 				pmap_free_pv_entry(pmap, pve);
@@ -2877,9 +2873,9 @@ do_l2b_alloc:
 			}
 		}
 
-		if (PV_BEEN_EXECD(oflags))
+		if (is_exec)
 			cpu_tlb_flushID_SE(va);
-		else if (PV_BEEN_REFD(oflags))
+		else if (is_refd)
 			cpu_tlb_flushD_SE(va);
 	}
 
@@ -3488,8 +3484,8 @@ pmap_remove(pmap_t pmap, vm_offset_t sva, vm_offset_t eva)
 
 				pve = pmap_remove_pv(m, pmap, sva);
 				if (pve) {
-					is_exec = PV_BEEN_EXECD(pve->pv_flags);
-					is_refd = PV_BEEN_REFD(pve->pv_flags);
+					is_exec = PTE_BEEN_EXECD(pte);
+					is_refd = PTE_BEEN_REFD(pte);
 					pmap_free_pv_entry(pmap, pve);
 				}
 			}
diff --git a/sys/arm/include/pmap.h b/sys/arm/include/pmap.h
index 445b43f..ec40682 100644
--- a/sys/arm/include/pmap.h
+++ b/sys/arm/include/pmap.h
@@ -391,6 +391,7 @@ extern int pmap_needs_pte_sync;
 #define L2_S_REF		(L2_AP0(1))	/* reference flag */
 
 #define	L2_S_PROT_MASK		(L2_S_PROT_U|L2_S_PROT_R)
+#define	L2_S_EXECUTABLE(pte)	(!(pte & L2_XN))
 #define	L2_S_WRITABLE(pte)	(!(pte & L2_APX))
 #define	L2_S_REFERENCED(pte)	(!!(pte & L2_S_REF))