1 /* $OpenBSD: uvm_io.c,v 1.6 2001/08/11 10:57:22 art Exp $ */ 2 /* $NetBSD: uvm_io.c,v 1.10 2000/06/02 12:02:44 pk Exp $ */ 3 4 /* 5 * 6 * Copyright (c) 1997 Charles D. Cranor and Washington University. 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by Charles D. Cranor and 20 * Washington University. 21 * 4. The name of the author may not be used to endorse or promote products 22 * derived from this software without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 * 35 * from: Id: uvm_io.c,v 1.1.2.2 1997/12/30 12:02:00 mrg Exp 36 */ 37 38 /* 39 * uvm_io.c: uvm i/o ops 40 */ 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/mman.h> 45 #include <sys/proc.h> 46 #include <sys/malloc.h> 47 #include <sys/uio.h> 48 49 #include <vm/vm.h> 50 #include <vm/vm_page.h> 51 #include <vm/vm_kern.h> 52 53 #include <uvm/uvm.h> 54 55 /* 56 * functions 57 */ 58 59 /* 60 * uvm_io: perform I/O on a map 61 * 62 * => caller must have a reference to "map" so that it doesn't go away 63 * while we are working. 64 */ 65 66 int 67 uvm_io(map, uio) 68 vm_map_t map; 69 struct uio *uio; 70 { 71 vaddr_t baseva, endva, pageoffset, kva; 72 vsize_t chunksz, togo, sz; 73 vm_map_entry_t dead_entries; 74 int error; 75 76 /* 77 * step 0: sanity checks and set up for copy loop. start with a 78 * large chunk size. if we have trouble finding vm space we will 79 * reduce it. 80 */ 81 82 if (uio->uio_resid == 0) 83 return(0); 84 togo = uio->uio_resid; 85 86 baseva = (vaddr_t) uio->uio_offset; 87 endva = baseva + (togo - 1); 88 89 if (endva < baseva) /* wrap around? */ 90 return(EIO); 91 92 if (baseva >= VM_MAXUSER_ADDRESS) 93 return(0); 94 if (endva >= VM_MAXUSER_ADDRESS) 95 /* EOF truncate */ 96 togo = togo - (endva - VM_MAXUSER_ADDRESS + 1); 97 pageoffset = baseva & PAGE_MASK; 98 baseva = trunc_page(baseva); 99 chunksz = min(round_page(togo + pageoffset), MAXBSIZE); 100 error = 0; 101 102 /* 103 * step 1: main loop... while we've got data to move 104 */ 105 106 for (/*null*/; togo > 0 ; pageoffset = 0) { 107 108 /* 109 * step 2: extract mappings from the map into kernel_map 110 */ 111 112 error = uvm_map_extract(map, baseva, chunksz, kernel_map, &kva, 113 UVM_EXTRACT_QREF | UVM_EXTRACT_CONTIG | 114 UVM_EXTRACT_FIXPROT); 115 if (error) { 116 117 /* retry with a smaller chunk... */ 118 if (error == ENOMEM && chunksz > PAGE_SIZE) { 119 chunksz = trunc_page(chunksz / 2); 120 if (chunksz < PAGE_SIZE) 121 chunksz = PAGE_SIZE; 122 continue; 123 } 124 125 break; 126 } 127 128 /* 129 * step 3: move a chunk of data 130 */ 131 132 sz = chunksz - pageoffset; 133 if (sz > togo) 134 sz = togo; 135 error = uiomove((caddr_t) (kva + pageoffset), sz, uio); 136 if (error) 137 break; 138 togo -= sz; 139 baseva += chunksz; 140 141 142 /* 143 * step 4: unmap the area of kernel memory 144 */ 145 146 vm_map_lock(kernel_map); 147 (void)uvm_unmap_remove(kernel_map, kva, kva+chunksz, 148 &dead_entries); 149 vm_map_unlock(kernel_map); 150 151 if (dead_entries != NULL) 152 uvm_unmap_detach(dead_entries, AMAP_REFALL); 153 } 154 155 /* 156 * done 157 */ 158 159 return (error); 160 } 161