1 /* $NetBSD: kern_ras.c,v 1.9 2004/04/01 02:37:42 yamt Exp $ */ 2 3 /*- 4 * Copyright (c) 2002 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Gregory McGarry. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 __KERNEL_RCSID(0, "$NetBSD: kern_ras.c,v 1.9 2004/04/01 02:37:42 yamt Exp $"); 41 42 #include <sys/param.h> 43 #include <sys/lock.h> 44 #include <sys/systm.h> 45 #include <sys/pool.h> 46 #include <sys/proc.h> 47 #include <sys/ras.h> 48 #include <sys/sa.h> 49 #include <sys/savar.h> 50 51 #include <sys/mount.h> 52 #include <sys/syscallargs.h> 53 54 #include <uvm/uvm_extern.h> 55 56 #define MAX_RAS_PER_PROC 16 57 58 u_int ras_per_proc = MAX_RAS_PER_PROC; 59 60 #ifdef DEBUG 61 int ras_debug = 0; 62 #define DPRINTF(x) if (ras_debug) printf x 63 #else 64 #define DPRINTF(x) /* nothing */ 65 #endif 66 67 int ras_install(struct proc *, caddr_t, size_t); 68 int ras_purge(struct proc *, caddr_t, size_t); 69 70 /* 71 * Check the specified address to see if it is within the 72 * sequence. If it is found, we return the restart address, 73 * otherwise we return -1. If we do perform a restart, we 74 * mark the sequence as hit. 75 */ 76 caddr_t 77 ras_lookup(struct proc *p, caddr_t addr) 78 { 79 struct ras *rp; 80 81 #ifdef DIAGNOSTIC 82 if (addr < (caddr_t)VM_MIN_ADDRESS || 83 addr > (caddr_t)VM_MAXUSER_ADDRESS) 84 return ((caddr_t)-1); 85 #endif 86 87 simple_lock(&p->p_lock); 88 LIST_FOREACH(rp, &p->p_raslist, ras_list) { 89 if (addr > rp->ras_startaddr && addr < rp->ras_endaddr) { 90 rp->ras_hits++; 91 simple_unlock(&p->p_lock); 92 #ifdef DIAGNOSTIC 93 DPRINTF(("RAS hit: p=%p %p\n", p, addr)); 94 #endif 95 return (rp->ras_startaddr); 96 } 97 } 98 simple_unlock(&p->p_lock); 99 100 return ((caddr_t)-1); 101 } 102 103 /* 104 * During a fork, we copy all of the sequences from parent p1 to 105 * the child p2. 106 */ 107 int 108 ras_fork(struct proc *p1, struct proc *p2) 109 { 110 struct ras *rp, *nrp; 111 int nras; 112 113 again: 114 /* 115 * first, try to shortcut. 116 */ 117 118 if (LIST_EMPTY(&p1->p_raslist)) 119 return (0); 120 121 /* 122 * count entries. 123 */ 124 125 nras = 0; 126 simple_lock(&p1->p_lock); 127 LIST_FOREACH(rp, &p1->p_raslist, ras_list) 128 nras++; 129 simple_unlock(&p1->p_lock); 130 131 /* 132 * allocate entries. 133 */ 134 135 for ( ; nras > 0; nras--) { 136 nrp = pool_get(&ras_pool, PR_WAITOK); 137 nrp->ras_hits = 0; 138 LIST_INSERT_HEAD(&p2->p_raslist, nrp, ras_list); 139 } 140 141 /* 142 * copy entries. 143 */ 144 145 simple_lock(&p1->p_lock); 146 nrp = LIST_FIRST(&p2->p_raslist); 147 LIST_FOREACH(rp, &p1->p_raslist, ras_list) { 148 if (nrp == NULL) 149 break; 150 nrp->ras_startaddr = rp->ras_startaddr; 151 nrp->ras_endaddr = rp->ras_endaddr; 152 nrp = LIST_NEXT(nrp, ras_list); 153 } 154 simple_unlock(&p1->p_lock); 155 156 /* 157 * if we lose a race, retry. 158 */ 159 160 if (rp != NULL || nrp != NULL) { 161 ras_purgeall(p2); 162 goto again; 163 } 164 165 DPRINTF(("ras_fork: p1=%p, p2=%p, nras=%d\n", p1, p2, nras)); 166 167 return (0); 168 } 169 170 /* 171 * Nuke all sequences for this process. 172 */ 173 int 174 ras_purgeall(struct proc *p) 175 { 176 struct ras *rp; 177 178 simple_lock(&p->p_lock); 179 while (!LIST_EMPTY(&p->p_raslist)) { 180 rp = LIST_FIRST(&p->p_raslist); 181 DPRINTF(("RAS %p-%p, hits %d\n", rp->ras_startaddr, 182 rp->ras_endaddr, rp->ras_hits)); 183 LIST_REMOVE(rp, ras_list); 184 pool_put(&ras_pool, rp); 185 } 186 simple_unlock(&p->p_lock); 187 188 return (0); 189 } 190 191 /* 192 * Install the new sequence. If it already exists, return 193 * an error. 194 */ 195 int 196 ras_install(struct proc *p, caddr_t addr, size_t len) 197 { 198 struct ras *rp; 199 struct ras *newrp; 200 caddr_t endaddr = addr + len; 201 int nras = 0; 202 203 if (addr < (caddr_t)VM_MIN_ADDRESS || 204 endaddr > (caddr_t)VM_MAXUSER_ADDRESS) 205 return (EINVAL); 206 207 if (len <= 0) 208 return (EINVAL); 209 210 newrp = NULL; 211 again: 212 simple_lock(&p->p_lock); 213 LIST_FOREACH(rp, &p->p_raslist, ras_list) { 214 if (++nras >= ras_per_proc || 215 (addr < rp->ras_endaddr && endaddr > rp->ras_startaddr)) { 216 simple_unlock(&p->p_lock); 217 return (EINVAL); 218 } 219 } 220 if (newrp == NULL) { 221 simple_unlock(&p->p_lock); 222 newrp = pool_get(&ras_pool, PR_WAITOK); 223 goto again; 224 } 225 newrp->ras_startaddr = addr; 226 newrp->ras_endaddr = endaddr; 227 newrp->ras_hits = 0; 228 LIST_INSERT_HEAD(&p->p_raslist, newrp, ras_list); 229 simple_unlock(&p->p_lock); 230 231 return (0); 232 } 233 234 /* 235 * Nuke the specified sequence. Both address and len must 236 * match, otherwise we return an error. 237 */ 238 int 239 ras_purge(struct proc *p, caddr_t addr, size_t len) 240 { 241 struct ras *rp; 242 caddr_t endaddr = addr + len; 243 int error = ESRCH; 244 245 simple_lock(&p->p_lock); 246 LIST_FOREACH(rp, &p->p_raslist, ras_list) { 247 if (addr == rp->ras_startaddr && endaddr == rp->ras_endaddr) { 248 LIST_REMOVE(rp, ras_list); 249 pool_put(&ras_pool, rp); 250 error = 0; 251 break; 252 } 253 } 254 simple_unlock(&p->p_lock); 255 256 return (error); 257 } 258 259 /*ARGSUSED*/ 260 int 261 sys_rasctl(struct lwp *l, void *v, register_t *retval) 262 { 263 264 #if defined(__HAVE_RAS) 265 266 struct sys_rasctl_args /* { 267 syscallarg(caddr_t) addr; 268 syscallarg(size_t) len; 269 syscallarg(int) op; 270 } */ *uap = v; 271 struct proc *p = l->l_proc; 272 caddr_t addr; 273 size_t len; 274 int op; 275 int error; 276 277 /* 278 * first, extract syscall args from the uap. 279 */ 280 281 addr = (caddr_t)SCARG(uap, addr); 282 len = (size_t)SCARG(uap, len); 283 op = SCARG(uap, op); 284 285 DPRINTF(("sys_rasctl: p=%p addr=%p, len=%ld, op=0x%x\n", 286 p, addr, (long)len, op)); 287 288 switch (op) { 289 case RAS_INSTALL: 290 error = ras_install(p, addr, len); 291 break; 292 case RAS_PURGE: 293 error = ras_purge(p, addr, len); 294 break; 295 case RAS_PURGE_ALL: 296 error = ras_purgeall(p); 297 break; 298 default: 299 error = EINVAL; 300 break; 301 } 302 303 return (error); 304 305 #else 306 307 return (EOPNOTSUPP); 308 309 #endif 310 311 } 312