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Date:      Wed, 18 Nov 2009 18:05:54 +0000 (UTC)
From:      Alan Cox <alc@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r199490 - head/sys/vm
Message-ID:  <200911181805.nAII5s1J079483@svn.freebsd.org>
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Author: alc
Date: Wed Nov 18 18:05:54 2009
New Revision: 199490
URL: http://svn.freebsd.org/changeset/base/199490

Log:
  Simplify both the invocation and the implementation of vm_fault() for wiring
  pages.
  
  (Note: Claims made in the comments about the handling of breakpoints in
  wired pages have been false for roughly a decade.  This and another bug
  involving breakpoints will be fixed in coming changes.)
  
  Reviewed by:	kib

Modified:
  head/sys/vm/vm_extern.h
  head/sys/vm/vm_fault.c
  head/sys/vm/vm_map.c
  head/sys/vm/vm_map.h

Modified: head/sys/vm/vm_extern.h
==============================================================================
--- head/sys/vm/vm_extern.h	Wed Nov 18 17:51:54 2009	(r199489)
+++ head/sys/vm/vm_extern.h	Wed Nov 18 18:05:54 2009	(r199490)
@@ -58,7 +58,7 @@ int vm_fault(vm_map_t, vm_offset_t, vm_p
 void vm_fault_copy_entry(vm_map_t, vm_map_t, vm_map_entry_t, vm_map_entry_t,
     vm_ooffset_t *);
 void vm_fault_unwire(vm_map_t, vm_offset_t, vm_offset_t, boolean_t);
-int vm_fault_wire(vm_map_t, vm_offset_t, vm_offset_t, boolean_t, boolean_t);
+int vm_fault_wire(vm_map_t, vm_offset_t, vm_offset_t, boolean_t);
 int vm_forkproc(struct thread *, struct proc *, struct thread *, struct vmspace *, int);
 void vm_waitproc(struct proc *);
 int vm_mmap(vm_map_t, vm_offset_t *, vm_size_t, vm_prot_t, vm_prot_t, int, objtype_t, void *, vm_ooffset_t);

Modified: head/sys/vm/vm_fault.c
==============================================================================
--- head/sys/vm/vm_fault.c	Wed Nov 18 17:51:54 2009	(r199489)
+++ head/sys/vm/vm_fault.c	Wed Nov 18 18:05:54 2009	(r199490)
@@ -185,7 +185,7 @@ unlock_and_deallocate(struct faultstate 
  *	      default objects are zero-fill, there is no real pager.
  */
 #define TRYPAGER	(fs.object->type != OBJT_DEFAULT && \
-			(((fault_flags & VM_FAULT_WIRE_MASK) == 0) || wired))
+			((fault_flags & VM_FAULT_CHANGE_WIRING) == 0 || wired))
 
 /*
  *	vm_fault:
@@ -238,31 +238,15 @@ RetryFault:;
 	result = vm_map_lookup(&fs.map, vaddr, fault_type, &fs.entry,
 	    &fs.first_object, &fs.first_pindex, &prot, &wired);
 	if (result != KERN_SUCCESS) {
-		if (result != KERN_PROTECTION_FAILURE ||
-		    (fault_flags & VM_FAULT_WIRE_MASK) != VM_FAULT_USER_WIRE) {
-			if (growstack && result == KERN_INVALID_ADDRESS &&
-			    map != kernel_map && curproc != NULL) {
-				result = vm_map_growstack(curproc, vaddr);
-				if (result != KERN_SUCCESS)
-					return (KERN_FAILURE);
-				growstack = FALSE;
-				goto RetryFault;
-			}
-			return (result);
+		if (growstack && result == KERN_INVALID_ADDRESS &&
+		    map != kernel_map) {
+			result = vm_map_growstack(curproc, vaddr);
+			if (result != KERN_SUCCESS)
+				return (KERN_FAILURE);
+			growstack = FALSE;
+			goto RetryFault;
 		}
-
-		/*
-   		 * If we are user-wiring a r/w segment, and it is COW, then
-   		 * we need to do the COW operation.  Note that we don't COW
-   		 * currently RO sections now, because it is NOT desirable
-   		 * to COW .text.  We simply keep .text from ever being COW'ed
-   		 * and take the heat that one cannot debug wired .text sections.
-   		 */
-		result = vm_map_lookup(&fs.map, vaddr,
-			VM_PROT_READ|VM_PROT_WRITE|VM_PROT_OVERRIDE_WRITE,
-			&fs.entry, &fs.first_object, &fs.first_pindex, &prot, &wired);
-		if (result != KERN_SUCCESS)
-			return (result);
+		return (result);
 	}
 
 	map_generation = fs.map->timestamp;
@@ -919,9 +903,8 @@ vnode_locked:
 	 * won't find it (yet).
 	 */
 	pmap_enter(fs.map->pmap, vaddr, fault_type, fs.m, prot, wired);
-	if (((fault_flags & VM_FAULT_WIRE_MASK) == 0) && (wired == 0)) {
+	if ((fault_flags & VM_FAULT_CHANGE_WIRING) == 0 && wired == 0)
 		vm_fault_prefault(fs.map->pmap, vaddr, fs.entry);
-	}
 	VM_OBJECT_LOCK(fs.object);
 	vm_page_lock_queues();
 	vm_page_flag_set(fs.m, PG_REFERENCED);
@@ -930,7 +913,7 @@ vnode_locked:
 	 * If the page is not wired down, then put it where the pageout daemon
 	 * can find it.
 	 */
-	if (fault_flags & VM_FAULT_WIRE_MASK) {
+	if (fault_flags & VM_FAULT_CHANGE_WIRING) {
 		if (wired)
 			vm_page_wire(fs.m);
 		else
@@ -1048,7 +1031,7 @@ vm_fault_quick(caddr_t v, int prot)
  */
 int
 vm_fault_wire(vm_map_t map, vm_offset_t start, vm_offset_t end,
-    boolean_t user_wire, boolean_t fictitious)
+    boolean_t fictitious)
 {
 	vm_offset_t va;
 	int rv;
@@ -1059,9 +1042,7 @@ vm_fault_wire(vm_map_t map, vm_offset_t 
 	 * read-only sections.
 	 */
 	for (va = start; va < end; va += PAGE_SIZE) {
-		rv = vm_fault(map, va,
-		    user_wire ? VM_PROT_READ : VM_PROT_READ | VM_PROT_WRITE,
-		    user_wire ? VM_FAULT_USER_WIRE : VM_FAULT_CHANGE_WIRING);
+		rv = vm_fault(map, va, VM_PROT_NONE, VM_FAULT_CHANGE_WIRING);
 		if (rv) {
 			if (va != start)
 				vm_fault_unwire(map, start, va, fictitious);

Modified: head/sys/vm/vm_map.c
==============================================================================
--- head/sys/vm/vm_map.c	Wed Nov 18 17:51:54 2009	(r199489)
+++ head/sys/vm/vm_map.c	Wed Nov 18 18:05:54 2009	(r199490)
@@ -2381,7 +2381,7 @@ vm_map_wire(vm_map_t map, vm_offset_t st
 			 */
 			vm_map_unlock(map);
 			rv = vm_fault_wire(map, saved_start, saved_end,
-			    user_wire, fictitious);
+			    fictitious);
 			vm_map_lock(map);
 			if (last_timestamp + 1 != map->timestamp) {
 				/*
@@ -3563,7 +3563,7 @@ RetryLookup:;
 	else
 		prot = entry->protection;
 	fault_type &= (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
-	if ((fault_type & prot) != fault_type) {
+	if ((fault_type & prot) != fault_type || prot == VM_PROT_NONE) {
 		vm_map_unlock_read(map);
 		return (KERN_PROTECTION_FAILURE);
 	}

Modified: head/sys/vm/vm_map.h
==============================================================================
--- head/sys/vm/vm_map.h	Wed Nov 18 17:51:54 2009	(r199489)
+++ head/sys/vm/vm_map.h	Wed Nov 18 18:05:54 2009	(r199490)
@@ -319,8 +319,6 @@ long vmspace_wired_count(struct vmspace 
  */
 #define VM_FAULT_NORMAL 0		/* Nothing special */
 #define VM_FAULT_CHANGE_WIRING 1	/* Change the wiring as appropriate */
-#define VM_FAULT_USER_WIRE 2		/* Likewise, but for user purposes */
-#define VM_FAULT_WIRE_MASK (VM_FAULT_CHANGE_WIRING|VM_FAULT_USER_WIRE)
 #define VM_FAULT_DIRTY 8		/* Dirty the page */
 
 /*

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