git: 0fb6aae7f0e1 - main - vm_map.c: add CONTAINS_BITS macro

The branch main has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=0fb6aae7f0e19c0628c398bbe30297ef9245030e

commit 0fb6aae7f0e19c0628c398bbe30297ef9245030e
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2023-07-29 17:52:52 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2023-08-12 06:28:13 +0000

    vm_map.c: add CONTAINS_BITS macro
    
    Suggested by:   dougm
    Reviewed by:    alc, markj
    Tested by:      pho
    Sponsored by:   The FreeBSD Foundation
    MFC after:      1 week
    Differential revision:  https://reviews.freebsd.org/D41099
---
 sys/vm/vm_map.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
index f8a2903567a6..8c12f2a92bcb 100644
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@@ -148,6 +148,8 @@ static int vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos,
 static void vm_map_wire_entry_failure(vm_map_t map, vm_map_entry_t entry,
     vm_offset_t failed_addr);
 
+#define	CONTAINS_BITS(set, bits)	((~(set) & (bits)) == 0)
+
 #define	ENTRY_CHARGED(e) ((e)->cred != NULL || \
     ((e)->object.vm_object != NULL && (e)->object.vm_object->cred != NULL && \
      !((e)->eflags & MAP_ENTRY_NEEDS_COPY)))
@@ -2733,15 +2735,15 @@ vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end,
 	vm_map_entry_t entry, first_entry, in_tran, prev_entry;
 	vm_object_t obj;
 	struct ucred *cred;
-	vm_prot_t old_prot;
+	vm_prot_t check_prot, old_prot;
 	int rv;
 
 	if (start == end)
 		return (KERN_SUCCESS);
 
-	if ((flags & (VM_MAP_PROTECT_SET_PROT | VM_MAP_PROTECT_SET_MAXPROT)) ==
-	    (VM_MAP_PROTECT_SET_PROT | VM_MAP_PROTECT_SET_MAXPROT) &&
-	    (new_prot & new_maxprot) != new_prot)
+	if (CONTAINS_BITS(flags, VM_MAP_PROTECT_SET_PROT |
+	    VM_MAP_PROTECT_SET_MAXPROT) &&
+	    !CONTAINS_BITS(new_maxprot, new_prot))
 		return (KERN_OUT_OF_BOUNDS);
 
 again:
@@ -2750,8 +2752,7 @@ again:
 
 	if ((map->flags & MAP_WXORX) != 0 &&
 	    (flags & VM_MAP_PROTECT_SET_PROT) != 0 &&
-	    (new_prot & (VM_PROT_WRITE | VM_PROT_EXECUTE)) == (VM_PROT_WRITE |
-	    VM_PROT_EXECUTE)) {
+	    CONTAINS_BITS(new_prot, VM_PROT_WRITE | VM_PROT_EXECUTE)) {
 		vm_map_unlock(map);
 		return (KERN_PROTECTION_FAILURE);
 	}
@@ -2772,6 +2773,11 @@ again:
 	/*
 	 * Make a first pass to check for protection violations.
 	 */
+	check_prot = 0;
+	if ((flags & VM_MAP_PROTECT_SET_PROT) != 0)
+		check_prot |= new_prot;
+	if ((flags & VM_MAP_PROTECT_SET_MAXPROT) != 0)
+		check_prot |= new_maxprot;
 	for (entry = first_entry; entry->start < end;
 	    entry = vm_map_entry_succ(entry)) {
 		if ((entry->eflags & MAP_ENTRY_GUARD) != 0)
@@ -2780,12 +2786,7 @@ again:
 			vm_map_unlock(map);
 			return (KERN_INVALID_ARGUMENT);
 		}
-		if ((flags & VM_MAP_PROTECT_SET_PROT) == 0)
-			new_prot = entry->protection;
-		if ((flags & VM_MAP_PROTECT_SET_MAXPROT) == 0)
-			new_maxprot = entry->max_protection;
-		if ((new_prot & entry->max_protection) != new_prot ||
-		    (new_maxprot & entry->max_protection) != new_maxprot) {
+		if (!CONTAINS_BITS(entry->max_protection, check_prot)) {
 			vm_map_unlock(map);
 			return (KERN_PROTECTION_FAILURE);
 		}