kern_ras.c revision 1.18
1 /* $NetBSD: kern_ras.c,v 1.18 2007/03/12 18:18:33 ad Exp $ */ 2 3 /*- 4 * Copyright (c) 2002, 2006 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 1.18 2007/03/12 18:18:33 ad 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 49 #include <sys/mount.h> 50 #include <sys/syscallargs.h> 51 52 #include <uvm/uvm_extern.h> 53 54 POOL_INIT(ras_pool, sizeof(struct ras), 0, 0, 0, "raspl", 55 &pool_allocator_nointr, IPL_NONE); 56 57 #define MAX_RAS_PER_PROC 16 58 59 u_int ras_per_proc = MAX_RAS_PER_PROC; 60 61 #ifdef DEBUG 62 int ras_debug = 0; 63 #define DPRINTF(x) if (ras_debug) printf x 64 #else 65 #define DPRINTF(x) /* nothing */ 66 #endif 67 68 /* 69 * Check the specified address to see if it is within the 70 * sequence. If it is found, we return the restart address, 71 * otherwise we return -1. If we do perform a restart, we 72 * mark the sequence as hit. 73 */ 74 void * 75 ras_lookup(struct proc *p, void *addr) 76 { 77 struct ras *rp; 78 void *startaddr; 79 80 startaddr = (void *)-1; 81 82 #ifdef DIAGNOSTIC 83 if (addr < (void *)VM_MIN_ADDRESS || 84 addr > (void *)VM_MAXUSER_ADDRESS) 85 return (startaddr); 86 #endif 87 88 mutex_enter(&p->p_rasmutex); 89 LIST_FOREACH(rp, &p->p_raslist, ras_list) { 90 if (addr > rp->ras_startaddr && addr < rp->ras_endaddr) { 91 rp->ras_hits++; 92 startaddr = rp->ras_startaddr; 93 #ifdef DIAGNOSTIC 94 DPRINTF(("RAS hit: p=%p %p\n", p, addr)); 95 #endif 96 break; 97 } 98 } 99 mutex_exit(&p->p_rasmutex); 100 101 return (startaddr); 102 } 103 104 /* 105 * During a fork, we copy all of the sequences from parent p1 to 106 * the child p2. 107 */ 108 int 109 ras_fork(struct proc *p1, struct proc *p2) 110 { 111 struct ras *rp, *nrp; 112 int nras; 113 114 again: 115 /* 116 * first, try to shortcut. 117 */ 118 119 if (LIST_EMPTY(&p1->p_raslist)) 120 return (0); 121 122 /* 123 * count entries. 124 */ 125 126 nras = 0; 127 mutex_enter(&p1->p_rasmutex); 128 LIST_FOREACH(rp, &p1->p_raslist, ras_list) 129 nras++; 130 mutex_exit(&p1->p_rasmutex); 131 132 /* 133 * allocate entries. 134 */ 135 136 for ( ; nras > 0; nras--) { 137 nrp = pool_get(&ras_pool, PR_WAITOK); 138 nrp->ras_hits = 0; 139 LIST_INSERT_HEAD(&p2->p_raslist, nrp, ras_list); 140 } 141 142 /* 143 * copy entries. 144 */ 145 146 mutex_enter(&p1->p_rasmutex); 147 nrp = LIST_FIRST(&p2->p_raslist); 148 LIST_FOREACH(rp, &p1->p_raslist, ras_list) { 149 if (nrp == NULL) 150 break; 151 nrp->ras_startaddr = rp->ras_startaddr; 152 nrp->ras_endaddr = rp->ras_endaddr; 153 nrp = LIST_NEXT(nrp, ras_list); 154 } 155 mutex_exit(&p1->p_rasmutex); 156 157 /* 158 * if we lose a race, retry. 159 */ 160 161 if (rp != NULL || nrp != NULL) { 162 ras_purgeall(p2); 163 goto again; 164 } 165 166 DPRINTF(("ras_fork: p1=%p, p2=%p, nras=%d\n", p1, p2, nras)); 167 168 return (0); 169 } 170 171 /* 172 * Nuke all sequences for this process. 173 */ 174 int 175 ras_purgeall(struct proc *p) 176 { 177 struct ras *rp; 178 179 mutex_enter(&p->p_rasmutex); 180 while (!LIST_EMPTY(&p->p_raslist)) { 181 rp = LIST_FIRST(&p->p_raslist); 182 DPRINTF(("RAS %p-%p, hits %d\n", rp->ras_startaddr, 183 rp->ras_endaddr, rp->ras_hits)); 184 LIST_REMOVE(rp, ras_list); 185 mutex_exit(&p->p_rasmutex); 186 pool_put(&ras_pool, rp); 187 mutex_enter(&p->p_rasmutex); 188 } 189 mutex_exit(&p->p_rasmutex); 190 191 return (0); 192 } 193 194 #if defined(__HAVE_RAS) 195 196 /* 197 * Install the new sequence. If it already exists, return 198 * an error. 199 */ 200 static int 201 ras_install(struct proc *p, void *addr, size_t len) 202 { 203 struct ras *rp; 204 struct ras *newrp; 205 void *endaddr = (char *)addr + len; 206 int nras = 0; 207 208 if (addr < (void *)VM_MIN_ADDRESS || 209 endaddr > (void *)VM_MAXUSER_ADDRESS) 210 return (EINVAL); 211 212 if (len <= 0) 213 return (EINVAL); 214 215 newrp = NULL; 216 again: 217 mutex_enter(&p->p_rasmutex); 218 LIST_FOREACH(rp, &p->p_raslist, ras_list) { 219 if (++nras >= ras_per_proc || 220 (addr < rp->ras_endaddr && endaddr > rp->ras_startaddr)) { 221 mutex_exit(&p->p_rasmutex); 222 return (EINVAL); 223 } 224 } 225 if (newrp == NULL) { 226 mutex_exit(&p->p_rasmutex); 227 newrp = pool_get(&ras_pool, PR_WAITOK); 228 goto again; 229 } 230 newrp->ras_startaddr = addr; 231 newrp->ras_endaddr = endaddr; 232 newrp->ras_hits = 0; 233 LIST_INSERT_HEAD(&p->p_raslist, newrp, ras_list); 234 mutex_exit(&p->p_rasmutex); 235 236 return (0); 237 } 238 239 /* 240 * Nuke the specified sequence. Both address and len must 241 * match, otherwise we return an error. 242 */ 243 static int 244 ras_purge(struct proc *p, void *addr, size_t len) 245 { 246 struct ras *rp; 247 void *endaddr = (char *)addr + len; 248 int error = ESRCH; 249 250 mutex_enter(&p->p_rasmutex); 251 LIST_FOREACH(rp, &p->p_raslist, ras_list) { 252 if (addr == rp->ras_startaddr && endaddr == rp->ras_endaddr) { 253 LIST_REMOVE(rp, ras_list); 254 break; 255 } 256 } 257 mutex_exit(&p->p_rasmutex); 258 259 if (rp != NULL) { 260 pool_put(&ras_pool, rp); 261 error = 0; 262 } 263 264 return (error); 265 } 266 267 #endif /* defined(__HAVE_RAS) */ 268 269 /*ARGSUSED*/ 270 int 271 sys_rasctl(struct lwp *l, void *v, register_t *retval) 272 { 273 274 #if defined(__HAVE_RAS) 275 276 struct sys_rasctl_args /* { 277 syscallarg(void *) addr; 278 syscallarg(size_t) len; 279 syscallarg(int) op; 280 } */ *uap = v; 281 struct proc *p = l->l_proc; 282 void *addr; 283 size_t len; 284 int op; 285 int error; 286 287 /* 288 * first, extract syscall args from the uap. 289 */ 290 291 addr = (void *)SCARG(uap, addr); 292 len = (size_t)SCARG(uap, len); 293 op = SCARG(uap, op); 294 295 DPRINTF(("sys_rasctl: p=%p addr=%p, len=%ld, op=0x%x\n", 296 p, addr, (long)len, op)); 297 298 switch (op) { 299 case RAS_INSTALL: 300 error = ras_install(p, addr, len); 301 break; 302 case RAS_PURGE: 303 error = ras_purge(p, addr, len); 304 break; 305 case RAS_PURGE_ALL: 306 error = ras_purgeall(p); 307 break; 308 default: 309 error = EINVAL; 310 break; 311 } 312 313 return (error); 314 315 #else 316 317 return (EOPNOTSUPP); 318 319 #endif 320 321 } 322
Indexes created Mon Sep 22 13:09:51 GMT 2025