1 /* 2 * Copyright (c) 1994 John S. Dyson 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice immediately at the beginning of the file, without modification, 10 * this list of conditions, and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Absolutely no warranty of function or purpose is made by the author 15 * John S. Dyson. 16 * 4. Modifications may be freely made to this file if the above conditions 17 * are met. 18 * 19 * $Id: kern_physio.c,v 1.6 1994/08/08 13:53:55 davidg Exp $ 20 */ 21 22 #include <sys/param.h> 23 #include <sys/systm.h> 24 #include <sys/buf.h> 25 #include <sys/conf.h> 26 #include <sys/proc.h> 27 #include <vm/vm.h> 28 29 static void physwakeup(); 30 31 int 32 physio(strategy, bp, dev, rw, minp, uio) 33 int (*strategy)(); 34 struct buf *bp; 35 dev_t dev; 36 int rw; 37 u_int (*minp)(); 38 struct uio *uio; 39 { 40 int i; 41 int bufflags = rw?B_READ:0; 42 int error; 43 int spl; 44 caddr_t sa; 45 int bp_alloc = (bp == 0); 46 struct buf *bpa; 47 48 /* 49 * keep the process from being swapped 50 */ 51 curproc->p_flag |= P_PHYSIO; 52 53 /* create and build a buffer header for a transfer */ 54 bpa = (struct buf *)getpbuf(); 55 if (!bp_alloc) { 56 spl = splbio(); 57 while (bp->b_flags & B_BUSY) { 58 bp->b_flags |= B_WANTED; 59 tsleep((caddr_t)bp, PRIBIO, "physbw", 0); 60 } 61 bp->b_flags |= B_BUSY; 62 splx(spl); 63 } else { 64 bp = bpa; 65 } 66 67 /* 68 * get a copy of the kva from the physical buffer 69 */ 70 sa = bpa->b_data; 71 bp->b_proc = curproc; 72 bp->b_dev = dev; 73 error = bp->b_error = 0; 74 75 for(i=0;i<uio->uio_iovcnt;i++) { 76 while( uio->uio_iov[i].iov_len) { 77 vm_offset_t v, lastv, pa; 78 caddr_t adr; 79 80 bp->b_bcount = uio->uio_iov[i].iov_len; 81 bp->b_bcount = minp( bp); 82 if( minp != minphys) 83 bp->b_bcount = minphys( bp); 84 bp->b_bufsize = bp->b_bcount; 85 bp->b_flags = B_BUSY | B_PHYS | B_CALL | bufflags; 86 bp->b_iodone = physwakeup; 87 bp->b_data = uio->uio_iov[i].iov_base; 88 /* 89 * pass in the kva from the physical buffer 90 * for the temporary kernel mapping. 91 */ 92 bp->b_saveaddr = sa; 93 bp->b_blkno = btodb(uio->uio_offset); 94 95 96 if (rw && !useracc(bp->b_data, bp->b_bufsize, B_WRITE)) { 97 error = EFAULT; 98 goto doerror; 99 } 100 if (!rw && !useracc(bp->b_data, bp->b_bufsize, B_READ)) { 101 error = EFAULT; 102 goto doerror; 103 } 104 105 vmapbuf(bp); 106 107 /* perform transfer */ 108 (*strategy)(bp); 109 110 spl = splbio(); 111 while ((bp->b_flags & B_DONE) == 0) 112 tsleep((caddr_t)bp, PRIBIO, "physstr", 0); 113 splx(spl); 114 115 vunmapbuf(bp); 116 117 /* 118 * update the uio data 119 */ 120 { 121 int iolen = bp->b_bcount - bp->b_resid; 122 123 if (iolen == 0 && !(bp->b_flags & B_ERROR)) 124 goto doerror; /* EOF */ 125 uio->uio_iov[i].iov_len -= iolen; 126 uio->uio_iov[i].iov_base += iolen; 127 uio->uio_resid -= iolen; 128 uio->uio_offset += iolen; 129 } 130 131 /* 132 * check for an error 133 */ 134 if( bp->b_flags & B_ERROR) { 135 error = bp->b_error; 136 goto doerror; 137 } 138 } 139 } 140 141 142 doerror: 143 relpbuf(bpa); 144 if (!bp_alloc) { 145 bp->b_flags &= ~(B_BUSY|B_PHYS); 146 if( bp->b_flags & B_WANTED) { 147 bp->b_flags &= ~B_WANTED; 148 wakeup((caddr_t)bp); 149 } 150 } 151 /* 152 * allow the process to be swapped 153 */ 154 curproc->p_flag &= ~P_PHYSIO; 155 156 return (error); 157 } 158 159 u_int 160 minphys(struct buf *bp) 161 { 162 163 if( bp->b_bcount > MAXBSIZE) { 164 bp->b_bcount = MAXBSIZE; 165 } 166 return bp->b_bcount; 167 } 168 169 int 170 rawread(dev_t dev, struct uio *uio) 171 { 172 return (physio(cdevsw[major(dev)].d_strategy, (struct buf *)NULL, 173 dev, 1, minphys, uio)); 174 } 175 176 int 177 rawwrite(dev_t dev, struct uio *uio) 178 { 179 return (physio(cdevsw[major(dev)].d_strategy, (struct buf *)NULL, 180 dev, 0, minphys, uio)); 181 } 182 183 static void 184 physwakeup(bp) 185 struct buf *bp; 186 { 187 wakeup((caddr_t) bp); 188 bp->b_flags &= ~B_CALL; 189 } 190