1 /* $NetBSD: uvm_io.c,v 1.24 2007/03/04 06:03:48 christos Exp $ */ 2 3 /* 4 * 5 * Copyright (c) 1997 Charles D. Cranor and Washington University. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by Charles D. Cranor and 19 * Washington University. 20 * 4. The name of the author may not be used to endorse or promote products 21 * derived from this software without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 * 34 * from: Id: uvm_io.c,v 1.1.2.2 1997/12/30 12:02:00 mrg Exp 35 */ 36 37 /* 38 * uvm_io.c: uvm i/o ops 39 */ 40 41 #include <sys/cdefs.h> 42 __KERNEL_RCSID(0, "$NetBSD: uvm_io.c,v 1.24 2007/03/04 06:03:48 christos Exp $"); 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/mman.h> 47 #include <sys/proc.h> 48 #include <sys/malloc.h> 49 #include <sys/uio.h> 50 51 #include <uvm/uvm.h> 52 53 /* 54 * functions 55 */ 56 57 /* 58 * uvm_io: perform I/O on a map 59 * 60 * => caller must have a reference to "map" so that it doesn't go away 61 * while we are working. 62 */ 63 64 int 65 uvm_io(struct vm_map *map, struct uio *uio) 66 { 67 vaddr_t baseva, endva, pageoffset, kva; 68 vsize_t chunksz, togo, sz; 69 struct vm_map_entry *dead_entries; 70 int error; 71 72 /* 73 * step 0: sanity checks and set up for copy loop. start with a 74 * large chunk size. if we have trouble finding vm space we will 75 * reduce it. 76 */ 77 78 if (uio->uio_resid == 0) 79 return(0); 80 togo = uio->uio_resid; 81 82 baseva = (vaddr_t) uio->uio_offset; 83 endva = baseva + (togo - 1); 84 85 if (endva < baseva) /* wrap around? */ 86 return(EIO); 87 88 if (baseva >= VM_MAXUSER_ADDRESS) 89 return(0); 90 if (endva >= VM_MAXUSER_ADDRESS) 91 /* EOF truncate */ 92 togo = togo - (endva - VM_MAXUSER_ADDRESS + 1); 93 pageoffset = baseva & PAGE_MASK; 94 baseva = trunc_page(baseva); 95 chunksz = MIN(round_page(togo + pageoffset), trunc_page(MAXPHYS)); 96 error = 0; 97 98 /* 99 * step 1: main loop... while we've got data to move 100 */ 101 102 for (/*null*/; togo > 0 ; pageoffset = 0) { 103 104 /* 105 * step 2: extract mappings from the map into kernel_map 106 */ 107 108 error = uvm_map_extract(map, baseva, chunksz, kernel_map, &kva, 109 UVM_EXTRACT_QREF | UVM_EXTRACT_CONTIG | 110 UVM_EXTRACT_FIXPROT); 111 if (error) { 112 113 /* retry with a smaller chunk... */ 114 if (error == ENOMEM && chunksz > PAGE_SIZE) { 115 chunksz = trunc_page(chunksz / 2); 116 if (chunksz < PAGE_SIZE) 117 chunksz = PAGE_SIZE; 118 continue; 119 } 120 121 break; 122 } 123 124 /* 125 * step 3: move a chunk of data 126 */ 127 128 sz = chunksz - pageoffset; 129 if (sz > togo) 130 sz = togo; 131 error = uiomove((void *) (kva + pageoffset), sz, uio); 132 togo -= sz; 133 baseva += chunksz; 134 135 /* 136 * step 4: unmap the area of kernel memory 137 */ 138 139 vm_map_lock(kernel_map); 140 uvm_unmap_remove(kernel_map, kva, kva + chunksz, &dead_entries, 141 NULL, 0); 142 vm_map_unlock(kernel_map); 143 if (dead_entries != NULL) 144 uvm_unmap_detach(dead_entries, AMAP_REFALL); 145 146 if (error) 147 break; 148 } 149 return (error); 150 } 151