1 /* $NetBSD: uvm_io.c,v 1.7 1998/10/11 23:18:20 chuck Exp $ */ 2 3 /* 4 * XXXCDC: "ROUGH DRAFT" QUALITY UVM PRE-RELEASE FILE! 5 * >>>USE AT YOUR OWN RISK, WORK IS NOT FINISHED<<< 6 */ 7 /* 8 * 9 * Copyright (c) 1997 Charles D. Cranor and Washington University. 10 * All rights reserved. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by Charles D. Cranor and 23 * Washington University. 24 * 4. The name of the author may not be used to endorse or promote products 25 * derived from this software without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 28 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 29 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 30 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 31 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 32 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 33 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 34 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 36 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 37 * 38 * from: Id: uvm_io.c,v 1.1.2.2 1997/12/30 12:02:00 mrg Exp 39 */ 40 41 /* 42 * uvm_io.c: uvm i/o ops 43 */ 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/mman.h> 48 #include <sys/proc.h> 49 #include <sys/malloc.h> 50 #include <sys/uio.h> 51 52 #include <vm/vm.h> 53 #include <vm/vm_page.h> 54 #include <vm/vm_kern.h> 55 56 #include <uvm/uvm.h> 57 58 /* 59 * functions 60 */ 61 62 /* 63 * uvm_io: perform I/O on a map 64 * 65 * => caller must have a reference to "map" so that it doesn't go away 66 * while we are working. 67 */ 68 69 int 70 uvm_io(map, uio) 71 vm_map_t map; 72 struct uio *uio; 73 { 74 vaddr_t baseva, endva, pageoffset, kva; 75 vsize_t chunksz, togo, sz; 76 vm_map_entry_t dead_entries; 77 int error; 78 79 /* 80 * step 0: sanity checks and set up for copy loop. start with a 81 * large chunk size. if we have trouble finding vm space we will 82 * reduce it. 83 */ 84 85 if (uio->uio_resid == 0) 86 return(0); 87 togo = uio->uio_resid; 88 89 baseva = (vaddr_t) uio->uio_offset; 90 endva = baseva + (togo - 1); 91 92 if (endva < baseva) /* wrap around? */ 93 return(EIO); 94 95 if (baseva >= VM_MAXUSER_ADDRESS) 96 return(0); 97 if (endva >= VM_MAXUSER_ADDRESS) 98 /* EOF truncate */ 99 togo = togo - (endva - VM_MAXUSER_ADDRESS + 1); 100 pageoffset = baseva & PAGE_MASK; 101 baseva = trunc_page(baseva); 102 chunksz = min(round_page(togo + pageoffset), MAXBSIZE); 103 error = 0; 104 105 /* 106 * step 1: main loop... while we've got data to move 107 */ 108 109 for (/*null*/; togo > 0 ; pageoffset = 0) { 110 111 /* 112 * step 2: extract mappings from the map into kernel_map 113 */ 114 115 error = uvm_map_extract(map, baseva, chunksz, kernel_map, &kva, 116 UVM_EXTRACT_QREF | UVM_EXTRACT_CONTIG | 117 UVM_EXTRACT_FIXPROT); 118 if (error) { 119 120 /* retry with a smaller chunk... */ 121 if (error == ENOMEM && chunksz > PAGE_SIZE) { 122 chunksz = trunc_page(chunksz / 2); 123 if (chunksz < PAGE_SIZE) 124 chunksz = PAGE_SIZE; 125 continue; 126 } 127 128 break; 129 } 130 131 /* 132 * step 3: move a chunk of data 133 */ 134 135 sz = chunksz - pageoffset; 136 if (sz > togo) 137 sz = togo; 138 error = uiomove((caddr_t) (kva + pageoffset), sz, uio); 139 if (error) 140 break; 141 togo -= sz; 142 baseva += chunksz; 143 144 145 /* 146 * step 4: unmap the area of kernel memory 147 */ 148 149 vm_map_lock(kernel_map); 150 (void)uvm_unmap_remove(kernel_map, kva, kva+chunksz, 151 &dead_entries); 152 vm_map_unlock(kernel_map); 153 154 if (dead_entries != NULL) 155 uvm_unmap_detach(dead_entries, AMAP_REFALL); 156 } 157 158 /* 159 * done 160 */ 161 162 return (error); 163 } 164