Beispiel #1
0
static int
spigen_mmap_single(struct cdev *cdev, vm_ooffset_t *offset,
                   vm_size_t size, struct vm_object **object, int nprot)
{
    device_t dev = cdev->si_drv1;
    struct spigen_softc *sc = device_get_softc(dev);
    vm_page_t *m;
    size_t n, pages;

    if (size == 0 ||
            (nprot & (PROT_EXEC | PROT_READ | PROT_WRITE))
            != (PROT_READ | PROT_WRITE))
        return (EINVAL);
    size = roundup2(size, PAGE_SIZE);
    pages = size / PAGE_SIZE;

    mtx_lock(&sc->sc_mtx);
    if (sc->sc_mmap_buffer != NULL) {
        mtx_unlock(&sc->sc_mtx);
        return (EBUSY);
    } else if (size > sc->sc_command_length_max + sc->sc_data_length_max) {
        mtx_unlock(&sc->sc_mtx);
        return (E2BIG);
    }
    sc->sc_mmap_buffer_size = size;
    *offset = 0;
    sc->sc_mmap_buffer = *object = vm_pager_allocate(OBJT_PHYS, 0, size,
                                   nprot, *offset, curthread->td_ucred);
    m = malloc(sizeof(*m) * pages, M_TEMP, M_WAITOK);
    VM_OBJECT_WLOCK(*object);
    vm_object_reference_locked(*object); // kernel and userland both
    for (n = 0; n < pages; n++) {
        m[n] = vm_page_grab(*object, n,
                            VM_ALLOC_NOBUSY | VM_ALLOC_ZERO | VM_ALLOC_WIRED);
        m[n]->valid = VM_PAGE_BITS_ALL;
    }
    VM_OBJECT_WUNLOCK(*object);
    sc->sc_mmap_kvaddr = kva_alloc(size);
    pmap_qenter(sc->sc_mmap_kvaddr, m, pages);
    free(m, M_TEMP);
    mtx_unlock(&sc->sc_mtx);

    if (*object == NULL)
        return (EINVAL);
    return (0);
}
Beispiel #2
0
int
vm_fault_hold(vm_map_t map, vm_offset_t vaddr, vm_prot_t fault_type,
    int fault_flags, vm_page_t *m_hold)
{
	vm_prot_t prot;
	long ahead, behind;
	int alloc_req, era, faultcount, nera, reqpage, result;
	boolean_t growstack, is_first_object_locked, wired;
	int map_generation;
	vm_object_t next_object;
	vm_page_t marray[VM_FAULT_READ_MAX];
	int hardfault;
	struct faultstate fs;
	struct vnode *vp;
	int locked, error;

	hardfault = 0;
	growstack = TRUE;
	PCPU_INC(cnt.v_vm_faults);
	fs.vp = NULL;
	faultcount = reqpage = 0;

RetryFault:;

	/*
	 * Find the backing store object and offset into it to begin the
	 * search.
	 */
	fs.map = map;
	result = vm_map_lookup(&fs.map, vaddr, fault_type, &fs.entry,
	    &fs.first_object, &fs.first_pindex, &prot, &wired);
	if (result != KERN_SUCCESS) {
		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;
		}
		return (result);
	}

	map_generation = fs.map->timestamp;

	if (fs.entry->eflags & MAP_ENTRY_NOFAULT) {
		panic("vm_fault: fault on nofault entry, addr: %lx",
		    (u_long)vaddr);
	}

	/*
	 * Make a reference to this object to prevent its disposal while we
	 * are messing with it.  Once we have the reference, the map is free
	 * to be diddled.  Since objects reference their shadows (and copies),
	 * they will stay around as well.
	 *
	 * Bump the paging-in-progress count to prevent size changes (e.g. 
	 * truncation operations) during I/O.  This must be done after
	 * obtaining the vnode lock in order to avoid possible deadlocks.
	 */
	VM_OBJECT_WLOCK(fs.first_object);
	vm_object_reference_locked(fs.first_object);
	vm_object_pip_add(fs.first_object, 1);

	fs.lookup_still_valid = TRUE;

	if (wired)
		fault_type = prot | (fault_type & VM_PROT_COPY);

	fs.first_m = NULL;

	/*
	 * Search for the page at object/offset.
	 */
	fs.object = fs.first_object;
	fs.pindex = fs.first_pindex;
	while (TRUE) {
		/*
		 * If the object is dead, we stop here
		 */
		if (fs.object->flags & OBJ_DEAD) {
			unlock_and_deallocate(&fs);
			return (KERN_PROTECTION_FAILURE);
		}

		/*
		 * See if page is resident
		 */
		fs.m = vm_page_lookup(fs.object, fs.pindex);
		if (fs.m != NULL) {
			/* 
			 * check for page-based copy on write.
			 * We check fs.object == fs.first_object so
			 * as to ensure the legacy COW mechanism is
			 * used when the page in question is part of
			 * a shadow object.  Otherwise, vm_page_cowfault()
			 * removes the page from the backing object, 
			 * which is not what we want.
			 */
			vm_page_lock(fs.m);
			if ((fs.m->cow) && 
			    (fault_type & VM_PROT_WRITE) &&
			    (fs.object == fs.first_object)) {
				vm_page_cowfault(fs.m);
				unlock_and_deallocate(&fs);
				goto RetryFault;
			}

			/*
			 * Wait/Retry if the page is busy.  We have to do this
			 * if the page is busy via either VPO_BUSY or 
			 * vm_page_t->busy because the vm_pager may be using
			 * vm_page_t->busy for pageouts ( and even pageins if
			 * it is the vnode pager ), and we could end up trying
			 * to pagein and pageout the same page simultaneously.
			 *
			 * We can theoretically allow the busy case on a read
			 * fault if the page is marked valid, but since such
			 * pages are typically already pmap'd, putting that
			 * special case in might be more effort then it is 
			 * worth.  We cannot under any circumstances mess
			 * around with a vm_page_t->busy page except, perhaps,
			 * to pmap it.
			 */
			if ((fs.m->oflags & VPO_BUSY) || fs.m->busy) {
				/*
				 * Reference the page before unlocking and
				 * sleeping so that the page daemon is less
				 * likely to reclaim it. 
				 */
				vm_page_aflag_set(fs.m, PGA_REFERENCED);
				vm_page_unlock(fs.m);
				if (fs.object != fs.first_object) {
					if (!VM_OBJECT_TRYWLOCK(
					    fs.first_object)) {
						VM_OBJECT_WUNLOCK(fs.object);
						VM_OBJECT_WLOCK(fs.first_object);
						VM_OBJECT_WLOCK(fs.object);
					}
					vm_page_lock(fs.first_m);
					vm_page_free(fs.first_m);
					vm_page_unlock(fs.first_m);
					vm_object_pip_wakeup(fs.first_object);
					VM_OBJECT_WUNLOCK(fs.first_object);
					fs.first_m = NULL;
				}
				unlock_map(&fs);
				if (fs.m == vm_page_lookup(fs.object,
				    fs.pindex)) {
					vm_page_sleep_if_busy(fs.m, TRUE,
					    "vmpfw");
				}
				vm_object_pip_wakeup(fs.object);
				VM_OBJECT_WUNLOCK(fs.object);
				PCPU_INC(cnt.v_intrans);
				vm_object_deallocate(fs.first_object);
				goto RetryFault;
			}
			vm_page_remque(fs.m);
			vm_page_unlock(fs.m);

			/*
			 * Mark page busy for other processes, and the 
			 * pagedaemon.  If it still isn't completely valid
			 * (readable), jump to readrest, else break-out ( we
			 * found the page ).
			 */
			vm_page_busy(fs.m);
			if (fs.m->valid != VM_PAGE_BITS_ALL)
				goto readrest;
			break;
		}

		/*
		 * Page is not resident, If this is the search termination
		 * or the pager might contain the page, allocate a new page.
		 */
		if (TRYPAGER || fs.object == fs.first_object) {
			if (fs.pindex >= fs.object->size) {
				unlock_and_deallocate(&fs);
				return (KERN_PROTECTION_FAILURE);
			}

			/*
			 * Allocate a new page for this object/offset pair.
			 *
			 * Unlocked read of the p_flag is harmless. At
			 * worst, the P_KILLED might be not observed
			 * there, and allocation can fail, causing
			 * restart and new reading of the p_flag.
			 */
			fs.m = NULL;
			if (!vm_page_count_severe() || P_KILLED(curproc)) {
#if VM_NRESERVLEVEL > 0
				if ((fs.object->flags & OBJ_COLORED) == 0) {
					fs.object->flags |= OBJ_COLORED;
					fs.object->pg_color = atop(vaddr) -
					    fs.pindex;
				}
#endif
				alloc_req = P_KILLED(curproc) ?
				    VM_ALLOC_SYSTEM : VM_ALLOC_NORMAL;
				if (fs.object->type != OBJT_VNODE &&
				    fs.object->backing_object == NULL)
					alloc_req |= VM_ALLOC_ZERO;
				fs.m = vm_page_alloc(fs.object, fs.pindex,
				    alloc_req);
			}
			if (fs.m == NULL) {
				unlock_and_deallocate(&fs);
				VM_WAITPFAULT;
				goto RetryFault;
			} else if (fs.m->valid == VM_PAGE_BITS_ALL)
				break;
		}

readrest:
		/*
		 * We have found a valid page or we have allocated a new page.
		 * The page thus may not be valid or may not be entirely 
		 * valid.
		 *
		 * Attempt to fault-in the page if there is a chance that the
		 * pager has it, and potentially fault in additional pages
		 * at the same time.
		 */
		if (TRYPAGER) {
			int rv;
			u_char behavior = vm_map_entry_behavior(fs.entry);

			if (behavior == MAP_ENTRY_BEHAV_RANDOM ||
			    P_KILLED(curproc)) {
				behind = 0;
				ahead = 0;
			} else if (behavior == MAP_ENTRY_BEHAV_SEQUENTIAL) {
				behind = 0;
				ahead = atop(fs.entry->end - vaddr) - 1;
				if (ahead > VM_FAULT_READ_AHEAD_MAX)
					ahead = VM_FAULT_READ_AHEAD_MAX;
				if (fs.pindex == fs.entry->next_read)
					vm_fault_cache_behind(&fs,
					    VM_FAULT_READ_MAX);
			} else {
				/*
				 * If this is a sequential page fault, then
				 * arithmetically increase the number of pages
				 * in the read-ahead window.  Otherwise, reset
				 * the read-ahead window to its smallest size.
				 */
				behind = atop(vaddr - fs.entry->start);
				if (behind > VM_FAULT_READ_BEHIND)
					behind = VM_FAULT_READ_BEHIND;
				ahead = atop(fs.entry->end - vaddr) - 1;
				era = fs.entry->read_ahead;
				if (fs.pindex == fs.entry->next_read) {
					nera = era + behind;
					if (nera > VM_FAULT_READ_AHEAD_MAX)
						nera = VM_FAULT_READ_AHEAD_MAX;
					behind = 0;
					if (ahead > nera)
						ahead = nera;
					if (era == VM_FAULT_READ_AHEAD_MAX)
						vm_fault_cache_behind(&fs,
						    VM_FAULT_CACHE_BEHIND);
				} else if (ahead > VM_FAULT_READ_AHEAD_MIN)
					ahead = VM_FAULT_READ_AHEAD_MIN;
				if (era != ahead)
					fs.entry->read_ahead = ahead;
			}

			/*
			 * Call the pager to retrieve the data, if any, after
			 * releasing the lock on the map.  We hold a ref on
			 * fs.object and the pages are VPO_BUSY'd.
			 */
			unlock_map(&fs);

			if (fs.object->type == OBJT_VNODE) {
				vp = fs.object->handle;
				if (vp == fs.vp)
					goto vnode_locked;
				else if (fs.vp != NULL) {
					vput(fs.vp);
					fs.vp = NULL;
				}
				locked = VOP_ISLOCKED(vp);

				if (locked != LK_EXCLUSIVE)
					locked = LK_SHARED;
				/* Do not sleep for vnode lock while fs.m is busy */
				error = vget(vp, locked | LK_CANRECURSE |
				    LK_NOWAIT, curthread);
				if (error != 0) {
					vhold(vp);
					release_page(&fs);
					unlock_and_deallocate(&fs);
					error = vget(vp, locked | LK_RETRY |
					    LK_CANRECURSE, curthread);
					vdrop(vp);
					fs.vp = vp;
					KASSERT(error == 0,
					    ("vm_fault: vget failed"));
					goto RetryFault;
				}
				fs.vp = vp;
			}
vnode_locked:
			KASSERT(fs.vp == NULL || !fs.map->system_map,
			    ("vm_fault: vnode-backed object mapped by system map"));

			/*
			 * now we find out if any other pages should be paged
			 * in at this time this routine checks to see if the
			 * pages surrounding this fault reside in the same
			 * object as the page for this fault.  If they do,
			 * then they are faulted in also into the object.  The
			 * array "marray" returned contains an array of
			 * vm_page_t structs where one of them is the
			 * vm_page_t passed to the routine.  The reqpage
			 * return value is the index into the marray for the
			 * vm_page_t passed to the routine.
			 *
			 * fs.m plus the additional pages are VPO_BUSY'd.
			 */
			faultcount = vm_fault_additional_pages(
			    fs.m, behind, ahead, marray, &reqpage);

			rv = faultcount ?
			    vm_pager_get_pages(fs.object, marray, faultcount,
				reqpage) : VM_PAGER_FAIL;

			if (rv == VM_PAGER_OK) {
				/*
				 * Found the page. Leave it busy while we play
				 * with it.
				 */

				/*
				 * Relookup in case pager changed page. Pager
				 * is responsible for disposition of old page
				 * if moved.
				 */
				fs.m = vm_page_lookup(fs.object, fs.pindex);
				if (!fs.m) {
					unlock_and_deallocate(&fs);
					goto RetryFault;
				}

				hardfault++;
				break; /* break to PAGE HAS BEEN FOUND */
			}
			/*
			 * Remove the bogus page (which does not exist at this
			 * object/offset); before doing so, we must get back
			 * our object lock to preserve our invariant.
			 *
			 * Also wake up any other process that may want to bring
			 * in this page.
			 *
			 * If this is the top-level object, we must leave the
			 * busy page to prevent another process from rushing
			 * past us, and inserting the page in that object at
			 * the same time that we are.
			 */
			if (rv == VM_PAGER_ERROR)
				printf("vm_fault: pager read error, pid %d (%s)\n",
				    curproc->p_pid, curproc->p_comm);
			/*
			 * Data outside the range of the pager or an I/O error
			 */
			/*
			 * XXX - the check for kernel_map is a kludge to work
			 * around having the machine panic on a kernel space
			 * fault w/ I/O error.
			 */
			if (((fs.map != kernel_map) && (rv == VM_PAGER_ERROR)) ||
				(rv == VM_PAGER_BAD)) {
				vm_page_lock(fs.m);
				vm_page_free(fs.m);
				vm_page_unlock(fs.m);
				fs.m = NULL;
				unlock_and_deallocate(&fs);
				return ((rv == VM_PAGER_ERROR) ? KERN_FAILURE : KERN_PROTECTION_FAILURE);
			}
			if (fs.object != fs.first_object) {
				vm_page_lock(fs.m);
				vm_page_free(fs.m);
				vm_page_unlock(fs.m);
				fs.m = NULL;
				/*
				 * XXX - we cannot just fall out at this
				 * point, m has been freed and is invalid!
				 */
			}
		}

		/*
		 * We get here if the object has default pager (or unwiring) 
		 * or the pager doesn't have the page.
		 */
		if (fs.object == fs.first_object)
			fs.first_m = fs.m;

		/*
		 * Move on to the next object.  Lock the next object before
		 * unlocking the current one.
		 */
		fs.pindex += OFF_TO_IDX(fs.object->backing_object_offset);
		next_object = fs.object->backing_object;
		if (next_object == NULL) {
			/*
			 * If there's no object left, fill the page in the top
			 * object with zeros.
			 */
			if (fs.object != fs.first_object) {
				vm_object_pip_wakeup(fs.object);
				VM_OBJECT_WUNLOCK(fs.object);

				fs.object = fs.first_object;
				fs.pindex = fs.first_pindex;
				fs.m = fs.first_m;
				VM_OBJECT_WLOCK(fs.object);
			}
			fs.first_m = NULL;

			/*
			 * Zero the page if necessary and mark it valid.
			 */
			if ((fs.m->flags & PG_ZERO) == 0) {
				pmap_zero_page(fs.m);
			} else {
				PCPU_INC(cnt.v_ozfod);
			}
			PCPU_INC(cnt.v_zfod);
			fs.m->valid = VM_PAGE_BITS_ALL;
			break;	/* break to PAGE HAS BEEN FOUND */
		} else {
			KASSERT(fs.object != next_object,
			    ("object loop %p", next_object));
			VM_OBJECT_WLOCK(next_object);
			vm_object_pip_add(next_object, 1);
			if (fs.object != fs.first_object)
				vm_object_pip_wakeup(fs.object);
			VM_OBJECT_WUNLOCK(fs.object);
			fs.object = next_object;
		}
	}

	KASSERT((fs.m->oflags & VPO_BUSY) != 0,
	    ("vm_fault: not busy after main loop"));

	/*
	 * PAGE HAS BEEN FOUND. [Loop invariant still holds -- the object lock
	 * is held.]
	 */

	/*
	 * If the page is being written, but isn't already owned by the
	 * top-level object, we have to copy it into a new page owned by the
	 * top-level object.
	 */
	if (fs.object != fs.first_object) {
		/*
		 * We only really need to copy if we want to write it.
		 */
		if ((fault_type & (VM_PROT_COPY | VM_PROT_WRITE)) != 0) {
			/*
			 * This allows pages to be virtually copied from a 
			 * backing_object into the first_object, where the 
			 * backing object has no other refs to it, and cannot
			 * gain any more refs.  Instead of a bcopy, we just 
			 * move the page from the backing object to the 
			 * first object.  Note that we must mark the page 
			 * dirty in the first object so that it will go out 
			 * to swap when needed.
			 */
			is_first_object_locked = FALSE;
			if (
				/*
				 * Only one shadow object
				 */
				(fs.object->shadow_count == 1) &&
				/*
				 * No COW refs, except us
				 */
				(fs.object->ref_count == 1) &&
				/*
				 * No one else can look this object up
				 */
				(fs.object->handle == NULL) &&
				/*
				 * No other ways to look the object up
				 */
				((fs.object->type == OBJT_DEFAULT) ||
				 (fs.object->type == OBJT_SWAP)) &&
			    (is_first_object_locked = VM_OBJECT_TRYWLOCK(fs.first_object)) &&
				/*
				 * We don't chase down the shadow chain
				 */
			    fs.object == fs.first_object->backing_object) {
				/*
				 * get rid of the unnecessary page
				 */
				vm_page_lock(fs.first_m);
				vm_page_free(fs.first_m);
				vm_page_unlock(fs.first_m);
				/*
				 * grab the page and put it into the 
				 * process'es object.  The page is 
				 * automatically made dirty.
				 */
				vm_page_lock(fs.m);
				vm_page_rename(fs.m, fs.first_object, fs.first_pindex);
				vm_page_unlock(fs.m);
				vm_page_busy(fs.m);
				fs.first_m = fs.m;
				fs.m = NULL;
				PCPU_INC(cnt.v_cow_optim);
			} else {
				/*
				 * Oh, well, lets copy it.
				 */
				pmap_copy_page(fs.m, fs.first_m);
				fs.first_m->valid = VM_PAGE_BITS_ALL;
				if (wired && (fault_flags &
				    VM_FAULT_CHANGE_WIRING) == 0) {
					vm_page_lock(fs.first_m);
					vm_page_wire(fs.first_m);
					vm_page_unlock(fs.first_m);
					
					vm_page_lock(fs.m);
					vm_page_unwire(fs.m, FALSE);
					vm_page_unlock(fs.m);
				}
				/*
				 * We no longer need the old page or object.
				 */
				release_page(&fs);
			}
			/*
			 * fs.object != fs.first_object due to above 
			 * conditional
			 */
			vm_object_pip_wakeup(fs.object);
			VM_OBJECT_WUNLOCK(fs.object);
			/*
			 * Only use the new page below...
			 */
			fs.object = fs.first_object;
			fs.pindex = fs.first_pindex;
			fs.m = fs.first_m;
			if (!is_first_object_locked)
				VM_OBJECT_WLOCK(fs.object);
			PCPU_INC(cnt.v_cow_faults);
			curthread->td_cow++;
		} else {
			prot &= ~VM_PROT_WRITE;
		}
	}

	/*
	 * We must verify that the maps have not changed since our last
	 * lookup.
	 */
	if (!fs.lookup_still_valid) {
		vm_object_t retry_object;
		vm_pindex_t retry_pindex;
		vm_prot_t retry_prot;

		if (!vm_map_trylock_read(fs.map)) {
			release_page(&fs);
			unlock_and_deallocate(&fs);
			goto RetryFault;
		}
		fs.lookup_still_valid = TRUE;
		if (fs.map->timestamp != map_generation) {
			result = vm_map_lookup_locked(&fs.map, vaddr, fault_type,
			    &fs.entry, &retry_object, &retry_pindex, &retry_prot, &wired);

			/*
			 * If we don't need the page any longer, put it on the inactive
			 * list (the easiest thing to do here).  If no one needs it,
			 * pageout will grab it eventually.
			 */
			if (result != KERN_SUCCESS) {
				release_page(&fs);
				unlock_and_deallocate(&fs);

				/*
				 * If retry of map lookup would have blocked then
				 * retry fault from start.
				 */
				if (result == KERN_FAILURE)
					goto RetryFault;
				return (result);
			}
			if ((retry_object != fs.first_object) ||
			    (retry_pindex != fs.first_pindex)) {
				release_page(&fs);
				unlock_and_deallocate(&fs);
				goto RetryFault;
			}

			/*
			 * Check whether the protection has changed or the object has
			 * been copied while we left the map unlocked. Changing from
			 * read to write permission is OK - we leave the page
			 * write-protected, and catch the write fault. Changing from
			 * write to read permission means that we can't mark the page
			 * write-enabled after all.
			 */
			prot &= retry_prot;
		}
	}
	/*
	 * If the page was filled by a pager, update the map entry's
	 * last read offset.  Since the pager does not return the
	 * actual set of pages that it read, this update is based on
	 * the requested set.  Typically, the requested and actual
	 * sets are the same.
	 *
	 * XXX The following assignment modifies the map
	 * without holding a write lock on it.
	 */
	if (hardfault)
		fs.entry->next_read = fs.pindex + faultcount - reqpage;

	if ((prot & VM_PROT_WRITE) != 0 ||
	    (fault_flags & VM_FAULT_DIRTY) != 0) {
		vm_object_set_writeable_dirty(fs.object);

		/*
		 * If this is a NOSYNC mmap we do not want to set VPO_NOSYNC
		 * if the page is already dirty to prevent data written with
		 * the expectation of being synced from not being synced.
		 * Likewise if this entry does not request NOSYNC then make
		 * sure the page isn't marked NOSYNC.  Applications sharing
		 * data should use the same flags to avoid ping ponging.
		 */
		if (fs.entry->eflags & MAP_ENTRY_NOSYNC) {
			if (fs.m->dirty == 0)
				fs.m->oflags |= VPO_NOSYNC;
		} else {
			fs.m->oflags &= ~VPO_NOSYNC;
		}

		/*
		 * If the fault is a write, we know that this page is being
		 * written NOW so dirty it explicitly to save on 
		 * pmap_is_modified() calls later.
		 *
		 * Also tell the backing pager, if any, that it should remove
		 * any swap backing since the page is now dirty.
		 */
		if (((fault_type & VM_PROT_WRITE) != 0 &&
		    (fault_flags & VM_FAULT_CHANGE_WIRING) == 0) ||
		    (fault_flags & VM_FAULT_DIRTY) != 0) {
			vm_page_dirty(fs.m);
			vm_pager_page_unswapped(fs.m);
		}
	}

	/*
	 * Page had better still be busy
	 */
	KASSERT(fs.m->oflags & VPO_BUSY,
		("vm_fault: page %p not busy!", fs.m));
	/*
	 * Page must be completely valid or it is not fit to
	 * map into user space.  vm_pager_get_pages() ensures this.
	 */
	KASSERT(fs.m->valid == VM_PAGE_BITS_ALL,
	    ("vm_fault: page %p partially invalid", fs.m));
	VM_OBJECT_WUNLOCK(fs.object);

	/*
	 * Put this page into the physical map.  We had to do the unlock above
	 * because pmap_enter() may sleep.  We don't put the page
	 * back on the active queue until later so that the pageout daemon
	 * won't find it (yet).
	 */
	pmap_enter(fs.map->pmap, vaddr, fault_type, fs.m, prot, wired);
	if ((fault_flags & VM_FAULT_CHANGE_WIRING) == 0 && wired == 0)
		vm_fault_prefault(fs.map->pmap, vaddr, fs.entry);
	VM_OBJECT_WLOCK(fs.object);
	vm_page_lock(fs.m);

	/*
	 * If the page is not wired down, then put it where the pageout daemon
	 * can find it.
	 */
	if (fault_flags & VM_FAULT_CHANGE_WIRING) {
		if (wired)
			vm_page_wire(fs.m);
		else
			vm_page_unwire(fs.m, 1);
	} else
		vm_page_activate(fs.m);
	if (m_hold != NULL) {
		*m_hold = fs.m;
		vm_page_hold(fs.m);
	}
	vm_page_unlock(fs.m);
	vm_page_wakeup(fs.m);

	/*
	 * Unlock everything, and return
	 */
	unlock_and_deallocate(&fs);
	if (hardfault) {
		PCPU_INC(cnt.v_io_faults);
		curthread->td_ru.ru_majflt++;
	} else 
		curthread->td_ru.ru_minflt++;

	return (KERN_SUCCESS);
}
Beispiel #3
0
static int
link_elf_obj_load_file(const char *filename, linker_file_t * result)
{
	struct nlookupdata nd;
	struct thread  *td = curthread;	/* XXX */
	struct proc    *p = td->td_proc;
	char           *pathname;
	struct vnode   *vp;
	Elf_Ehdr       *hdr;
	Elf_Shdr       *shdr;
	Elf_Sym        *es;
	int		nbytes, i, j;
	vm_offset_t	mapbase;
	size_t		mapsize;
	int		error = 0;
	int		resid;
	elf_file_t	ef;
	linker_file_t	lf;
	int		symtabindex;
	int		symstrindex;
	int		shstrindex;
	int		nsym;
	int		pb, rl, ra;
	int		alignmask;

	/* XXX Hack for firmware loading where p == NULL */
	if (p == NULL) {
		p = &proc0;
	}

	KKASSERT(p != NULL);
	if (p->p_ucred == NULL) {
		kprintf("link_elf_obj_load_file: cannot load '%s' from filesystem"
			" this early\n", filename);
		return ENOENT;
	}
	shdr = NULL;
	lf = NULL;
	mapsize = 0;
	hdr = NULL;
	pathname = linker_search_path(filename);
	if (pathname == NULL)
		return ENOENT;

	error = nlookup_init(&nd, pathname, UIO_SYSSPACE, NLC_FOLLOW | NLC_LOCKVP);
	if (error == 0)
		error = vn_open(&nd, NULL, FREAD, 0);
	kfree(pathname, M_LINKER);
	if (error) {
		nlookup_done(&nd);
		return error;
	}
	vp = nd.nl_open_vp;
	nd.nl_open_vp = NULL;
	nlookup_done(&nd);

	/*
	 * Read the elf header from the file.
	 */
	hdr = kmalloc(sizeof(*hdr), M_LINKER, M_WAITOK);
	error = vn_rdwr(UIO_READ, vp, (void *)hdr, sizeof(*hdr), 0,
			UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
	if (error)
		goto out;
	if (resid != 0) {
		error = ENOEXEC;
		goto out;
	}
	if (!IS_ELF(*hdr)) {
		error = ENOEXEC;
		goto out;
	}

	if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
	    || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
		link_elf_obj_error(filename, "Unsupported file layout");
		error = ENOEXEC;
		goto out;
	}
	if (hdr->e_ident[EI_VERSION] != EV_CURRENT
	    || hdr->e_version != EV_CURRENT) {
		link_elf_obj_error(filename, "Unsupported file version");
		error = ENOEXEC;
		goto out;
	}
	if (hdr->e_type != ET_REL) {
		error = ENOSYS;
		goto out;
	}
	if (hdr->e_machine != ELF_TARG_MACH) {
		link_elf_obj_error(filename, "Unsupported machine");
		error = ENOEXEC;
		goto out;
	}

	ef = kmalloc(sizeof(struct elf_file), M_LINKER, M_WAITOK | M_ZERO);
	lf = linker_make_file(filename, ef, &link_elf_obj_file_ops);
	if (lf == NULL) {
		kfree(ef, M_LINKER);
		error = ENOMEM;
		goto out;
	}
	ef->nprogtab = 0;
	ef->e_shdr = NULL;
	ef->nreltab = 0;
	ef->nrelatab = 0;

	/* Allocate and read in the section header */
	nbytes = hdr->e_shnum * hdr->e_shentsize;
	if (nbytes == 0 || hdr->e_shoff == 0 ||
	    hdr->e_shentsize != sizeof(Elf_Shdr)) {
		error = ENOEXEC;
		goto out;
	}
	shdr = kmalloc(nbytes, M_LINKER, M_WAITOK);
	ef->e_shdr = shdr;
	error = vn_rdwr(UIO_READ, vp, (caddr_t) shdr, nbytes, hdr->e_shoff,
			UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
	if (error)
		goto out;
	if (resid) {
		error = ENOEXEC;
		goto out;
	}
	/* Scan the section header for information and table sizing. */
	nsym = 0;
	symtabindex = -1;
	symstrindex = -1;
	for (i = 0; i < hdr->e_shnum; i++) {
		if (shdr[i].sh_size == 0)
			continue;
		switch (shdr[i].sh_type) {
		case SHT_PROGBITS:
		case SHT_NOBITS:
			ef->nprogtab++;
			break;
		case SHT_SYMTAB:
			nsym++;
			symtabindex = i;
			symstrindex = shdr[i].sh_link;
			break;
		case SHT_REL:
			ef->nreltab++;
			break;
		case SHT_RELA:
			ef->nrelatab++;
			break;
		case SHT_STRTAB:
			break;
		}
	}
	if (ef->nprogtab == 0) {
		link_elf_obj_error(filename, "file has no contents");
		error = ENOEXEC;
		goto out;
	}
	if (nsym != 1) {
		/* Only allow one symbol table for now */
		link_elf_obj_error(filename, "file has no valid symbol table");
		error = ENOEXEC;
		goto out;
	}
	if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
	    shdr[symstrindex].sh_type != SHT_STRTAB) {
		link_elf_obj_error(filename, "file has invalid symbol strings");
		error = ENOEXEC;
		goto out;
	}
	/* Allocate space for tracking the load chunks */
	if (ef->nprogtab != 0)
		ef->progtab = kmalloc(ef->nprogtab * sizeof(*ef->progtab),
				      M_LINKER, M_WAITOK | M_ZERO);
	if (ef->nreltab != 0)
		ef->reltab = kmalloc(ef->nreltab * sizeof(*ef->reltab),
				     M_LINKER, M_WAITOK | M_ZERO);
	if (ef->nrelatab != 0)
		ef->relatab = kmalloc(ef->nrelatab * sizeof(*ef->relatab),
				      M_LINKER, M_WAITOK | M_ZERO);
	if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
	    (ef->nreltab != 0 && ef->reltab == NULL) ||
	    (ef->nrelatab != 0 && ef->relatab == NULL)) {
		error = ENOMEM;
		goto out;
	}
	if (symtabindex == -1)
		panic("lost symbol table index");
	/* Allocate space for and load the symbol table */
	ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
	ef->ddbsymtab = kmalloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
	error = vn_rdwr(UIO_READ, vp, (void *)ef->ddbsymtab,
			shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
			UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
	if (error)
		goto out;
	if (resid != 0) {
		error = EINVAL;
		goto out;
	}
	if (symstrindex == -1)
		panic("lost symbol string index");
	/* Allocate space for and load the symbol strings */
	ef->ddbstrcnt = shdr[symstrindex].sh_size;
	ef->ddbstrtab = kmalloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
	error = vn_rdwr(UIO_READ, vp, ef->ddbstrtab,
			shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
			UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
	if (error)
		goto out;
	if (resid != 0) {
		error = EINVAL;
		goto out;
	}
	/* Do we have a string table for the section names?  */
	shstrindex = -1;
	if (hdr->e_shstrndx != 0 &&
	    shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
		shstrindex = hdr->e_shstrndx;
		ef->shstrcnt = shdr[shstrindex].sh_size;
		ef->shstrtab = kmalloc(shdr[shstrindex].sh_size, M_LINKER,
				       M_WAITOK);
		error = vn_rdwr(UIO_READ, vp, ef->shstrtab,
				shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
				UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
		if (error)
			goto out;
		if (resid != 0) {
			error = EINVAL;
			goto out;
		}
	}
	/* Size up code/data(progbits) and bss(nobits). */
	alignmask = 0;
	for (i = 0; i < hdr->e_shnum; i++) {
		if (shdr[i].sh_size == 0)
			continue;
		switch (shdr[i].sh_type) {
		case SHT_PROGBITS:
		case SHT_NOBITS:
			alignmask = shdr[i].sh_addralign - 1;
			mapsize += alignmask;
			mapsize &= ~alignmask;
			mapsize += shdr[i].sh_size;
			break;
		}
	}

	/*
	 * We know how much space we need for the text/data/bss/etc. This
	 * stuff needs to be in a single chunk so that profiling etc can get
	 * the bounds and gdb can associate offsets with modules
	 */
	ef->object = vm_object_allocate(OBJT_DEFAULT,
					round_page(mapsize) >> PAGE_SHIFT);
	if (ef->object == NULL) {
		error = ENOMEM;
		goto out;
	}
	vm_object_hold(ef->object);
	vm_object_reference_locked(ef->object);
	ef->address = (caddr_t) vm_map_min(&kernel_map);
	ef->bytes = 0;

	/*
	 * In order to satisfy x86_64's architectural requirements on the
	 * location of code and data in the kernel's address space, request a
	 * mapping that is above the kernel.
	 *
	 * vkernel64's text+data is outside the managed VM space entirely.
	 */
#if defined(__x86_64__) && defined(_KERNEL_VIRTUAL)
	error = vkernel_module_memory_alloc(&mapbase, round_page(mapsize));
	vm_object_drop(ef->object);
#else
	mapbase = KERNBASE;
	error = vm_map_find(&kernel_map, ef->object, NULL,
			    0, &mapbase, round_page(mapsize),
			    PAGE_SIZE,
			    TRUE, VM_MAPTYPE_NORMAL,
			    VM_PROT_ALL, VM_PROT_ALL, FALSE);
	vm_object_drop(ef->object);
	if (error) {
		vm_object_deallocate(ef->object);
		ef->object = NULL;
		goto out;
	}
	/* Wire the pages */
	error = vm_map_wire(&kernel_map, mapbase,
			    mapbase + round_page(mapsize), 0);
#endif
	if (error != KERN_SUCCESS) {
		error = ENOMEM;
		goto out;
	}
	/* Inform the kld system about the situation */
	lf->address = ef->address = (caddr_t) mapbase;
	lf->size = round_page(mapsize);
	ef->bytes = mapsize;

	/*
	 * Now load code/data(progbits), zero bss(nobits), allocate space for
	 * and load relocs
	 */
	pb = 0;
	rl = 0;
	ra = 0;
	alignmask = 0;
	for (i = 0; i < hdr->e_shnum; i++) {
		if (shdr[i].sh_size == 0)
			continue;
		switch (shdr[i].sh_type) {
		case SHT_PROGBITS:
		case SHT_NOBITS:
			alignmask = shdr[i].sh_addralign - 1;
			mapbase += alignmask;
			mapbase &= ~alignmask;
			if (ef->shstrtab && shdr[i].sh_name != 0)
				ef->progtab[pb].name =
					ef->shstrtab + shdr[i].sh_name;
			else if (shdr[i].sh_type == SHT_PROGBITS)
				ef->progtab[pb].name = "<<PROGBITS>>";
			else
				ef->progtab[pb].name = "<<NOBITS>>";
#if 0
			if (ef->progtab[pb].name != NULL &&
			    !strcmp(ef->progtab[pb].name, "set_pcpu"))
				ef->progtab[pb].addr =
					dpcpu_alloc(shdr[i].sh_size);
#ifdef VIMAGE
			else if (ef->progtab[pb].name != NULL &&
				 !strcmp(ef->progtab[pb].name, VNET_SETNAME))
				ef->progtab[pb].addr =
					vnet_data_alloc(shdr[i].sh_size);
#endif
			else
#endif
				ef->progtab[pb].addr =
					(void *)(uintptr_t) mapbase;
			if (ef->progtab[pb].addr == NULL) {
				error = ENOSPC;
				goto out;
			}
			ef->progtab[pb].size = shdr[i].sh_size;
			ef->progtab[pb].sec = i;
			if (shdr[i].sh_type == SHT_PROGBITS) {
				error = vn_rdwr(UIO_READ, vp,
						ef->progtab[pb].addr,
						shdr[i].sh_size, shdr[i].sh_offset,
						UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred,
						&resid);
				if (error)
					goto out;
				if (resid != 0) {
					error = EINVAL;
					goto out;
				}
#if 0
				/* Initialize the per-cpu or vnet area. */
				if (ef->progtab[pb].addr != (void *)mapbase &&
				    !strcmp(ef->progtab[pb].name, "set_pcpu"))
					dpcpu_copy(ef->progtab[pb].addr,
						   shdr[i].sh_size);
#ifdef VIMAGE
				else if (ef->progtab[pb].addr !=
					 (void *)mapbase &&
					 !strcmp(ef->progtab[pb].name, VNET_SETNAME))
					vnet_data_copy(ef->progtab[pb].addr,
						       shdr[i].sh_size);
#endif
#endif
			} else
				bzero(ef->progtab[pb].addr, shdr[i].sh_size);

			/* Update all symbol values with the offset. */
			for (j = 0; j < ef->ddbsymcnt; j++) {
				es = &ef->ddbsymtab[j];
				if (es->st_shndx != i)
					continue;
				es->st_value += (Elf_Addr) ef->progtab[pb].addr;
			}
			mapbase += shdr[i].sh_size;
			pb++;
			break;
		case SHT_REL:
			ef->reltab[rl].rel = kmalloc(shdr[i].sh_size, M_LINKER, M_WAITOK);
			ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
			ef->reltab[rl].sec = shdr[i].sh_info;
			error = vn_rdwr(UIO_READ, vp,
					(void *)ef->reltab[rl].rel,
					shdr[i].sh_size, shdr[i].sh_offset,
					UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
			if (error)
				goto out;
			if (resid != 0) {
				error = EINVAL;
				goto out;
			}
			rl++;
			break;
		case SHT_RELA:
			ef->relatab[ra].rela = kmalloc(shdr[i].sh_size, M_LINKER, M_WAITOK);
			ef->relatab[ra].nrela = shdr[i].sh_size / sizeof(Elf_Rela);
			ef->relatab[ra].sec = shdr[i].sh_info;
			error = vn_rdwr(UIO_READ, vp,
					(void *)ef->relatab[ra].rela,
					shdr[i].sh_size, shdr[i].sh_offset,
					UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
			if (error)
				goto out;
			if (resid != 0) {
				error = EINVAL;
				goto out;
			}
			ra++;
			break;
		}
	}
	if (pb != ef->nprogtab)
		panic("lost progbits");
	if (rl != ef->nreltab)
		panic("lost reltab");
	if (ra != ef->nrelatab)
		panic("lost relatab");
	if (mapbase != (vm_offset_t) ef->address + mapsize)
		panic("mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)",
		      mapbase, ef->address, mapsize,
		      (vm_offset_t) ef->address + mapsize);

	/* Local intra-module relocations */
	link_elf_obj_reloc_local(lf);

	/* Pull in dependencies */
	error = linker_load_dependencies(lf);
	if (error)
		goto out;

	/* External relocations */
	error = relocate_file(lf);
	if (error)
		goto out;

	*result = lf;

out:
	if (error && lf)
		linker_file_unload(lf /*, LINKER_UNLOAD_FORCE */);
	if (hdr)
		kfree(hdr, M_LINKER);
	vn_unlock(vp);
	vn_close(vp, FREAD, NULL);

	return error;
}
vm_object_t
cdev_pager_allocate(void *handle, enum obj_type tp, struct cdev_pager_ops *ops,
	vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff, struct ucred *cred)
{
	cdev_t dev;
	vm_object_t object;
	u_short color;

	/*
	 * Offset should be page aligned.
	 */
	if (foff & PAGE_MASK)
		return (NULL);

	size = round_page64(size);

	if (ops->cdev_pg_ctor(handle, size, prot, foff, cred, &color) != 0)
		return (NULL);

	/*
	 * Look up pager, creating as necessary.
	 */
	mtx_lock(&dev_pager_mtx);
	object = vm_pager_object_lookup(&dev_pager_object_list, handle);
	if (object == NULL) {
		/*
		 * Allocate object and associate it with the pager.
		 */
		object = vm_object_allocate_hold(tp,
						 OFF_TO_IDX(foff + size));
		object->handle = handle;
		object->un_pager.devp.ops = ops;
		object->un_pager.devp.dev = handle;
		TAILQ_INIT(&object->un_pager.devp.devp_pglist);

		/*
		 * handle is only a device for old_dev_pager_ctor.
		 */
		if (ops->cdev_pg_ctor == old_dev_pager_ctor) {
			dev = handle;
			dev->si_object = object;
		}

		TAILQ_INSERT_TAIL(&dev_pager_object_list, object,
		    pager_object_list);

		vm_object_drop(object);
	} else {
		/*
		 * Gain a reference to the object.
		 */
		vm_object_hold(object);
		vm_object_reference_locked(object);
		if (OFF_TO_IDX(foff + size) > object->size)
			object->size = OFF_TO_IDX(foff + size);
		vm_object_drop(object);
	}
	mtx_unlock(&dev_pager_mtx);

	return (object);
}
Beispiel #5
0
static int
link_elf_load_file(const char* filename, linker_file_t* result)
{
    struct nlookupdata nd;
    struct thread *td = curthread;	/* XXX */
    struct proc *p = td->td_proc;
    struct vnode *vp;
    Elf_Ehdr *hdr;
    caddr_t firstpage;
    int nbytes, i;
    Elf_Phdr *phdr;
    Elf_Phdr *phlimit;
    Elf_Phdr *segs[2];
    int nsegs;
    Elf_Phdr *phdyn;
    Elf_Phdr *phphdr;
    caddr_t mapbase;
    size_t mapsize;
    Elf_Off base_offset;
    Elf_Addr base_vaddr;
    Elf_Addr base_vlimit;
    int error = 0;
    int resid;
    elf_file_t ef;
    linker_file_t lf;
    char *pathname;
    Elf_Shdr *shdr;
    int symtabindex;
    int symstrindex;
    int symcnt;
    int strcnt;

    /* XXX Hack for firmware loading where p == NULL */
    if (p == NULL) {
	p = &proc0;
    }

    KKASSERT(p != NULL);
    if (p->p_ucred == NULL) {
	kprintf("link_elf_load_file: cannot load '%s' from filesystem"
		" this early\n", filename);
	return ENOENT;
    }
    shdr = NULL;
    lf = NULL;
    pathname = linker_search_path(filename);
    if (pathname == NULL)
	return ENOENT;

    error = nlookup_init(&nd, pathname, UIO_SYSSPACE, NLC_FOLLOW|NLC_LOCKVP);
    if (error == 0)
	error = vn_open(&nd, NULL, FREAD, 0);
    kfree(pathname, M_LINKER);
    if (error) {
	nlookup_done(&nd);
	return error;
    }
    vp = nd.nl_open_vp;
    nd.nl_open_vp = NULL;
    nlookup_done(&nd);

    /*
     * Read the elf header from the file.
     */
    firstpage = kmalloc(PAGE_SIZE, M_LINKER, M_WAITOK);
    hdr = (Elf_Ehdr *)firstpage;
    error = vn_rdwr(UIO_READ, vp, firstpage, PAGE_SIZE, 0,
		    UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
    nbytes = PAGE_SIZE - resid;
    if (error)
	goto out;

    if (!IS_ELF(*hdr)) {
	error = ENOEXEC;
	goto out;
    }

    if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
      || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
	link_elf_error("Unsupported file layout");
	error = ENOEXEC;
	goto out;
    }
    if (hdr->e_ident[EI_VERSION] != EV_CURRENT
      || hdr->e_version != EV_CURRENT) {
	link_elf_error("Unsupported file version");
	error = ENOEXEC;
	goto out;
    }
    if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
	error = ENOSYS;
	goto out;
    }
    if (hdr->e_machine != ELF_TARG_MACH) {
	link_elf_error("Unsupported machine");
	error = ENOEXEC;
	goto out;
    }

    /*
     * We rely on the program header being in the first page.  This is
     * not strictly required by the ABI specification, but it seems to
     * always true in practice.  And, it simplifies things considerably.
     */
    if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
	  (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
	  (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
	link_elf_error("Unreadable program headers");

    /*
     * Scan the program header entries, and save key information.
     *
     * We rely on there being exactly two load segments, text and data,
     * in that order.
     */
    phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
    phlimit = phdr + hdr->e_phnum;
    nsegs = 0;
    phdyn = NULL;
    phphdr = NULL;
    while (phdr < phlimit) {
	switch (phdr->p_type) {

	case PT_LOAD:
	    if (nsegs == 2) {
		link_elf_error("Too many sections");
		error = ENOEXEC;
		goto out;
	    }
	    segs[nsegs] = phdr;
	    ++nsegs;
	    break;

	case PT_PHDR:
	    phphdr = phdr;
	    break;

	case PT_DYNAMIC:
	    phdyn = phdr;
	    break;

	case PT_INTERP:
	    error = ENOSYS;
	    goto out;
	}

	++phdr;
    }
    if (phdyn == NULL) {
	link_elf_error("Object is not dynamically-linked");
	error = ENOEXEC;
	goto out;
    }

    /*
     * Allocate the entire address space of the object, to stake out our
     * contiguous region, and to establish the base address for relocation.
     */
    base_offset = trunc_page(segs[0]->p_offset);
    base_vaddr = trunc_page(segs[0]->p_vaddr);
    base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz);
    mapsize = base_vlimit - base_vaddr;

    ef = kmalloc(sizeof(struct elf_file), M_LINKER, M_WAITOK | M_ZERO);
#ifdef SPARSE_MAPPING
    ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
    if (ef->object == NULL) {
	kfree(ef, M_LINKER);
	error = ENOMEM;
	goto out;
    }
    vm_object_hold(ef->object);
    vm_object_reference_locked(ef->object);
    ef->address = (caddr_t)vm_map_min(&kernel_map);
    error = vm_map_find(&kernel_map, ef->object, 0,
			(vm_offset_t *)&ef->address,
			mapsize, PAGE_SIZE,
			1, VM_MAPTYPE_NORMAL,
			VM_PROT_ALL, VM_PROT_ALL,
			0);
    vm_object_drop(ef->object);
    if (error) {
	vm_object_deallocate(ef->object);
	kfree(ef, M_LINKER);
	goto out;
    }
#else
    ef->address = kmalloc(mapsize, M_LINKER, M_WAITOK);
#endif
    mapbase = ef->address;

    /*
     * Read the text and data sections and zero the bss.
     */
    for (i = 0; i < 2; i++) {
	caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
	error = vn_rdwr(UIO_READ, vp,
			segbase, segs[i]->p_filesz, segs[i]->p_offset,
			UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
	if (error) {
#ifdef SPARSE_MAPPING
	    vm_map_remove(&kernel_map, (vm_offset_t) ef->address,
			  (vm_offset_t) ef->address
			  + (ef->object->size << PAGE_SHIFT));
	    vm_object_deallocate(ef->object);
#else
	    kfree(ef->address, M_LINKER);
#endif
	    kfree(ef, M_LINKER);
	    goto out;
	}
	bzero(segbase + segs[i]->p_filesz,
	      segs[i]->p_memsz - segs[i]->p_filesz);

#ifdef SPARSE_MAPPING
	/*
	 * Wire down the pages
	 */
	vm_map_wire(&kernel_map,
		    (vm_offset_t) segbase,
		    (vm_offset_t) segbase + segs[i]->p_memsz,
		    0);
#endif
    }

    ef->dynamic = (const Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);

    lf = linker_make_file(filename, ef, &link_elf_file_ops);
    if (lf == NULL) {
#ifdef SPARSE_MAPPING
	vm_map_remove(&kernel_map, (vm_offset_t) ef->address,
		      (vm_offset_t) ef->address
		      + (ef->object->size << PAGE_SHIFT));
	vm_object_deallocate(ef->object);
#else
	kfree(ef->address, M_LINKER);
#endif
	kfree(ef, M_LINKER);
	error = ENOMEM;
	goto out;
    }
    lf->address = ef->address;
    lf->size = mapsize;

    error = parse_dynamic(lf);
    if (error)
	goto out;
    link_elf_reloc_local(lf);
    error = linker_load_dependencies(lf);
    if (error)
	goto out;
    error = relocate_file(lf);
    if (error)
	goto out;

    /* Try and load the symbol table if it's present.  (you can strip it!) */
    nbytes = hdr->e_shnum * hdr->e_shentsize;
    if (nbytes == 0 || hdr->e_shoff == 0)
	goto nosyms;
    shdr = kmalloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
    error = vn_rdwr(UIO_READ, vp,
		    (caddr_t)shdr, nbytes, hdr->e_shoff,
		    UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
    if (error)
	goto out;
    symtabindex = -1;
    symstrindex = -1;
    for (i = 0; i < hdr->e_shnum; i++) {
	if (shdr[i].sh_type == SHT_SYMTAB) {
	    symtabindex = i;
	    symstrindex = shdr[i].sh_link;
	}
    }
    if (symtabindex < 0 || symstrindex < 0)
	goto nosyms;

    symcnt = shdr[symtabindex].sh_size;
    ef->symbase = kmalloc(symcnt, M_LINKER, M_WAITOK);
    strcnt = shdr[symstrindex].sh_size;
    ef->strbase = kmalloc(strcnt, M_LINKER, M_WAITOK);
    error = vn_rdwr(UIO_READ, vp,
		    ef->symbase, symcnt, shdr[symtabindex].sh_offset,
		    UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
    if (error)
	goto out;
    error = vn_rdwr(UIO_READ, vp,
		    ef->strbase, strcnt, shdr[symstrindex].sh_offset,
		    UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
    if (error)
	goto out;

    ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
    ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
    ef->ddbstrcnt = strcnt;
    ef->ddbstrtab = ef->strbase;

nosyms:

    *result = lf;

out:
    if (error && lf)
	linker_file_unload(lf);
    if (shdr)
	kfree(shdr, M_LINKER);
    if (firstpage)
	kfree(firstpage, M_LINKER);
    vn_unlock(vp);
    vn_close(vp, FREAD);

    return error;
}