| 1 | /* $NetBSD: uvm_io.c,v 1.28 2016/05/25 17:43:58 christos Exp $ */ |
| 2 | |
| 3 | /* |
| 4 | * Copyright (c) 1997 Charles D. Cranor and Washington University. |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * Redistribution and use in source and binary forms, with or without |
| 8 | * modification, are permitted provided that the following conditions |
| 9 | * are met: |
| 10 | * 1. Redistributions of source code must retain the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer. |
| 12 | * 2. Redistributions in binary form must reproduce the above copyright |
| 13 | * notice, this list of conditions and the following disclaimer in the |
| 14 | * documentation and/or other materials provided with the distribution. |
| 15 | * |
| 16 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 17 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 18 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 19 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 20 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 21 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 22 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 23 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 24 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 25 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 26 | * |
| 27 | * from: Id: uvm_io.c,v 1.1.2.2 1997/12/30 12:02:00 mrg Exp |
| 28 | */ |
| 29 | |
| 30 | /* |
| 31 | * uvm_io.c: uvm i/o ops |
| 32 | */ |
| 33 | |
| 34 | #include <sys/cdefs.h> |
| 35 | __KERNEL_RCSID(0, "$NetBSD: uvm_io.c,v 1.28 2016/05/25 17:43:58 christos Exp $" ); |
| 36 | |
| 37 | #include <sys/param.h> |
| 38 | #include <sys/systm.h> |
| 39 | #include <sys/mman.h> |
| 40 | #include <sys/uio.h> |
| 41 | |
| 42 | #include <uvm/uvm.h> |
| 43 | |
| 44 | /* |
| 45 | * functions |
| 46 | */ |
| 47 | |
| 48 | /* |
| 49 | * uvm_io: perform I/O on a map |
| 50 | * |
| 51 | * => caller must have a reference to "map" so that it doesn't go away |
| 52 | * while we are working. |
| 53 | */ |
| 54 | |
| 55 | int |
| 56 | uvm_io(struct vm_map *map, struct uio *uio, int flags) |
| 57 | { |
| 58 | vaddr_t baseva, endva, pageoffset, kva; |
| 59 | vsize_t chunksz, togo, sz; |
| 60 | struct vm_map_entry *dead_entries; |
| 61 | int error; |
| 62 | |
| 63 | /* |
| 64 | * step 0: sanity checks and set up for copy loop. start with a |
| 65 | * large chunk size. if we have trouble finding vm space we will |
| 66 | * reduce it. |
| 67 | */ |
| 68 | |
| 69 | if (uio->uio_resid == 0) |
| 70 | return(0); |
| 71 | togo = uio->uio_resid; |
| 72 | |
| 73 | baseva = (vaddr_t) uio->uio_offset; |
| 74 | endva = baseva + (togo - 1); |
| 75 | |
| 76 | if (endva < baseva) /* wrap around? */ |
| 77 | return(EIO); |
| 78 | |
| 79 | if (baseva >= VM_MAXUSER_ADDRESS) |
| 80 | return(0); |
| 81 | if (endva >= VM_MAXUSER_ADDRESS) |
| 82 | /* EOF truncate */ |
| 83 | togo = togo - (endva - VM_MAXUSER_ADDRESS + 1); |
| 84 | pageoffset = baseva & PAGE_MASK; |
| 85 | baseva = trunc_page(baseva); |
| 86 | chunksz = MIN(round_page(togo + pageoffset), trunc_page(MAXPHYS)); |
| 87 | error = 0; |
| 88 | |
| 89 | flags |= UVM_EXTRACT_QREF | UVM_EXTRACT_CONTIG | UVM_EXTRACT_FIXPROT; |
| 90 | /* |
| 91 | * step 1: main loop... while we've got data to move |
| 92 | */ |
| 93 | |
| 94 | for (/*null*/; togo > 0 ; pageoffset = 0) { |
| 95 | |
| 96 | /* |
| 97 | * step 2: extract mappings from the map into kernel_map |
| 98 | */ |
| 99 | |
| 100 | error = uvm_map_extract(map, baseva, chunksz, kernel_map, &kva, |
| 101 | flags); |
| 102 | if (error) { |
| 103 | |
| 104 | /* retry with a smaller chunk... */ |
| 105 | if (error == ENOMEM && chunksz > PAGE_SIZE) { |
| 106 | chunksz = trunc_page(chunksz / 2); |
| 107 | if (chunksz < PAGE_SIZE) |
| 108 | chunksz = PAGE_SIZE; |
| 109 | continue; |
| 110 | } |
| 111 | |
| 112 | break; |
| 113 | } |
| 114 | |
| 115 | /* |
| 116 | * step 3: move a chunk of data |
| 117 | */ |
| 118 | |
| 119 | sz = chunksz - pageoffset; |
| 120 | if (sz > togo) |
| 121 | sz = togo; |
| 122 | error = uiomove((void *) (kva + pageoffset), sz, uio); |
| 123 | togo -= sz; |
| 124 | baseva += chunksz; |
| 125 | |
| 126 | /* |
| 127 | * step 4: unmap the area of kernel memory |
| 128 | */ |
| 129 | |
| 130 | vm_map_lock(kernel_map); |
| 131 | uvm_unmap_remove(kernel_map, kva, kva + chunksz, &dead_entries, |
| 132 | 0); |
| 133 | vm_map_unlock(kernel_map); |
| 134 | if (dead_entries != NULL) |
| 135 | uvm_unmap_detach(dead_entries, AMAP_REFALL); |
| 136 | |
| 137 | if (error) |
| 138 | break; |
| 139 | } |
| 140 | return (error); |
| 141 | } |
| 142 | |