cleanup madvise code, add a few more sanity checks.
Reviewed by: Alan Cox <alc@cs.rice.edu>, dg@root.com
This commit is contained in:
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2b635927ac
commit
b430905573
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=51493
116
sys/vm/vm_map.c
116
sys/vm/vm_map.c
@ -1009,31 +1009,51 @@ vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end,
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* the vm_map_entry structure, or those effecting the underlying
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* objects.
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*/
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void
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int
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vm_map_madvise(map, start, end, behav)
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vm_map_t map;
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vm_offset_t start, end;
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int behav;
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{
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vm_map_entry_t current, entry;
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int modify_map;
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int modify_map = 0;
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modify_map = (behav == MADV_NORMAL || behav == MADV_SEQUENTIAL ||
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behav == MADV_RANDOM);
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/*
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* Some madvise calls directly modify the vm_map_entry, in which case
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* we need to use an exclusive lock on the map and we need to perform
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* various clipping operations. Otherwise we only need a read-lock
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* on the map.
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*/
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if (modify_map) {
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switch(behav) {
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case MADV_NORMAL:
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case MADV_SEQUENTIAL:
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case MADV_RANDOM:
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modify_map = 1;
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vm_map_lock(map);
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}
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else
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break;
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case MADV_WILLNEED:
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case MADV_DONTNEED:
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case MADV_FREE:
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vm_map_lock_read(map);
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break;
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default:
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return (KERN_INVALID_ARGUMENT);
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}
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/*
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* Locate starting entry and clip if necessary.
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*/
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VM_MAP_RANGE_CHECK(map, start, end);
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if (vm_map_lookup_entry(map, start, &entry)) {
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if (modify_map)
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vm_map_clip_start(map, entry, start);
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} else
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} else {
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entry = entry->next;
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}
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if (modify_map) {
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/*
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@ -1044,8 +1064,8 @@ vm_map_madvise(map, start, end, behav)
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*/
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for (current = entry;
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(current != &map->header) && (current->start < end);
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current = current->next) {
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current = current->next
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) {
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if (current->eflags & MAP_ENTRY_IS_SUB_MAP)
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continue;
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@ -1067,51 +1087,53 @@ vm_map_madvise(map, start, end, behav)
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vm_map_simplify_entry(map, current);
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}
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vm_map_unlock(map);
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}
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else {
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if (behav == MADV_FREE || behav == MADV_DONTNEED ||
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behav == MADV_WILLNEED) {
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vm_pindex_t pindex;
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int count;
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} else {
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vm_pindex_t pindex;
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int count;
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/*
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* madvise behaviors that are implemented in the underlying
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* vm_object.
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*
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* Since we don't clip the vm_map_entry, we have to clip
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* the vm_object pindex and count.
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*/
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for (current = entry;
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(current != &map->header) && (current->start < end);
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current = current->next) {
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/*
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* madvise behaviors that are implemented in the underlying
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* vm_object.
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*
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* Since we don't clip the vm_map_entry, we have to clip
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* the vm_object pindex and count.
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*/
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for (current = entry;
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(current != &map->header) && (current->start < end);
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current = current->next
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) {
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if (current->eflags & MAP_ENTRY_IS_SUB_MAP)
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continue;
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if (current->eflags & MAP_ENTRY_IS_SUB_MAP)
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continue;
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pindex = OFF_TO_IDX(current->offset);
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count = atop(current->end - current->start);
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pindex = OFF_TO_IDX(current->offset);
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count = atop(current->end - current->start);
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if (current->start < start) {
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pindex += atop(start - current->start);
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count -= atop(start - current->start);
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}
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if (current->end > end)
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count -= atop(current->end - end);
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if (current->start < start) {
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pindex += atop(start - current->start);
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count -= atop(start - current->start);
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}
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if (current->end > end)
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count -= atop(current->end - end);
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if (count <= 0)
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continue;
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if (count <= 0)
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continue;
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vm_object_madvise(current->object.vm_object,
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pindex, count, behav);
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if (behav == MADV_WILLNEED)
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pmap_object_init_pt(map->pmap, current->start,
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current->object.vm_object,
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pindex, (count << PAGE_SHIFT),
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0);
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vm_object_madvise(current->object.vm_object,
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pindex, count, behav);
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if (behav == MADV_WILLNEED) {
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pmap_object_init_pt(
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map->pmap,
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current->start,
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current->object.vm_object,
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pindex,
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(count << PAGE_SHIFT),
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0
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);
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}
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}
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vm_map_unlock_read(map);
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}
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return(0);
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}
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@ -2764,12 +2786,14 @@ vm_uiomove(mapa, srcobject, cp, cnta, uaddra, npages)
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TAILQ_REMOVE(&oldobject->shadow_head,
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first_object, shadow_list);
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oldobject->shadow_count--;
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/* XXX bump generation? */
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vm_object_deallocate(oldobject);
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}
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TAILQ_INSERT_TAIL(&srcobject->shadow_head,
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first_object, shadow_list);
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srcobject->shadow_count++;
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/* XXX bump generation? */
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first_object->backing_object = srcobject;
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}
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@ -361,7 +361,7 @@ int vm_map_protect __P((vm_map_t, vm_offset_t, vm_offset_t, vm_prot_t, boolean_t
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int vm_map_remove __P((vm_map_t, vm_offset_t, vm_offset_t));
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void vm_map_startup __P((void));
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int vm_map_submap __P((vm_map_t, vm_offset_t, vm_offset_t, vm_map_t));
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void vm_map_madvise __P((vm_map_t, vm_offset_t, vm_offset_t, int));
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int vm_map_madvise __P((vm_map_t, vm_offset_t, vm_offset_t, int));
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void vm_map_simplify_entry __P((vm_map_t, vm_map_entry_t));
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void vm_init2 __P((void));
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int vm_uiomove __P((vm_map_t, vm_object_t, off_t, int, vm_offset_t, int *));
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@ -136,6 +136,15 @@ ogetpagesize(p, uap)
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* modulo the PAGE_SIZE (POSIX 1003.1b). If the address is not
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* page-aligned, the actual mapping starts at trunc_page(addr)
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* and the return value is adjusted up by the page offset.
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*
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* Generally speaking, only character devices which are themselves
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* memory-based, such as a video framebuffer, can be mmap'd. Otherwise
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* there would be no cache coherency between a descriptor and a VM mapping
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* both to the same character device.
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*
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* Block devices can be mmap'd no matter what they represent. Cache coherency
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* is maintained as long as you do not write directly to the underlying
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* character device.
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*/
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#ifndef _SYS_SYSPROTO_H_
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struct mmap_args {
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@ -615,6 +624,12 @@ madvise(p, uap)
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struct madvise_args *uap;
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{
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vm_offset_t start, end;
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/*
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* Check for illegal behavior
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*/
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if (uap->behav < 0 || uap->behav > MADV_FREE)
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return (EINVAL);
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/*
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* Check for illegal addresses. Watch out for address wrap... Note
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* that VM_*_ADDRESS are not constants due to casts (argh).
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@ -636,8 +651,8 @@ madvise(p, uap)
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start = trunc_page((vm_offset_t) uap->addr);
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end = round_page((vm_offset_t) uap->addr + uap->len);
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vm_map_madvise(&p->p_vmspace->vm_map, start, end, uap->behav);
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if (vm_map_madvise(&p->p_vmspace->vm_map, start, end, uap->behav))
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return (EINVAL);
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return (0);
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}
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