1 /* $NetBSD: kern_ras.c,v 1.44 2026/01/04 01:37:23 riastradh Exp $ */ 2 3 /*- 4 * Copyright (c) 2002, 2006, 2007, 2008 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, and by Andrew Doran. 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 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __KERNEL_RCSID(0, "$NetBSD: kern_ras.c,v 1.44 2026/01/04 01:37:23 riastradh Exp $"); 34 35 #include <sys/param.h> 36 #include <sys/types.h> 37 38 #include <sys/kernel.h> 39 #include <sys/kmem.h> 40 #include <sys/proc.h> 41 #include <sys/ras.h> 42 #include <sys/sdt.h> 43 #include <sys/syscallargs.h> 44 #include <sys/systm.h> 45 #include <sys/xcall.h> 46 47 #include <uvm/uvm_extern.h> 48 49 #define MAX_RAS_PER_PROC 16 50 51 u_int ras_per_proc = MAX_RAS_PER_PROC; 52 53 #ifdef DEBUG 54 int ras_debug = 0; 55 #define DPRINTF(x) if (ras_debug) printf x 56 #else 57 #define DPRINTF(x) /* nothing */ 58 #endif 59 60 /* 61 * Force all CPUs through cpu_switchto(), waiting until complete. 62 * Context switching will drain the write buffer on the calling 63 * CPU. 64 */ 65 static void 66 ras_sync(void) 67 { 68 69 /* No need to sync if exiting or single threaded. */ 70 if (curproc->p_nlwps > 1 && ncpu > 1) { 71 xc_barrier(0); 72 } 73 } 74 75 /* 76 * Check the specified address to see if it is within the 77 * sequence. If it is found, we return the restart address, 78 * otherwise we return -1. If we do perform a restart, we 79 * mark the sequence as hit. 80 * 81 * No locking required: we disable preemption and ras_sync() 82 * guarantees that individual entries are valid while we still 83 * have visibility of them. 84 */ 85 void * 86 ras_lookup(struct proc *p, void *addr) 87 { 88 struct ras *rp; 89 void *startaddr; 90 lwp_t *l; 91 92 startaddr = (void *)-1; 93 l = curlwp; 94 95 KPREEMPT_DISABLE(l); 96 for (rp = p->p_raslist; rp != NULL; rp = rp->ras_next) { 97 if (addr > rp->ras_startaddr && addr < rp->ras_endaddr) { 98 startaddr = rp->ras_startaddr; 99 DPRINTF(("RAS hit: p=%p %p\n", p, addr)); 100 break; 101 } 102 } 103 KPREEMPT_ENABLE(l); 104 105 return startaddr; 106 } 107 108 /* 109 * During a fork, we copy all of the sequences from parent p1 to 110 * the child p2. 111 * 112 * No locking required as the parent must be paused. 113 */ 114 int 115 ras_fork(struct proc *p1, struct proc *p2) 116 { 117 struct ras *rp, *nrp; 118 119 for (rp = p1->p_raslist; rp != NULL; rp = rp->ras_next) { 120 nrp = kmem_alloc(sizeof(*nrp), KM_SLEEP); 121 nrp->ras_startaddr = rp->ras_startaddr; 122 nrp->ras_endaddr = rp->ras_endaddr; 123 nrp->ras_next = p2->p_raslist; 124 p2->p_raslist = nrp; 125 } 126 127 DPRINTF(("ras_fork: p1=%p, p2=%p\n", p1, p2)); 128 129 return 0; 130 } 131 132 /* 133 * Nuke all sequences for this process. 134 */ 135 int 136 ras_purgeall(void) 137 { 138 struct ras *rp, *nrp; 139 proc_t *p; 140 141 p = curproc; 142 143 if (p->p_raslist == NULL) 144 return 0; 145 146 mutex_enter(&p->p_auxlock); 147 if ((rp = p->p_raslist) != NULL) { 148 p->p_raslist = NULL; 149 ras_sync(); 150 for(; rp != NULL; rp = nrp) { 151 nrp = rp->ras_next; 152 kmem_free(rp, sizeof(*rp)); 153 } 154 } 155 mutex_exit(&p->p_auxlock); 156 157 return 0; 158 } 159 160 #if defined(__HAVE_RAS) 161 162 /* 163 * Install the new sequence. If it already exists, return 164 * an error. 165 */ 166 static int 167 ras_install(void *addr, size_t len) 168 { 169 struct ras *rp; 170 struct ras *newrp; 171 void *endaddr; 172 int nras, error; 173 proc_t *p; 174 175 if (len == 0) 176 return SET_ERROR(EINVAL); 177 178 if ((uintptr_t)addr < VM_MIN_ADDRESS || 179 (uintptr_t)addr > VM_MAXUSER_ADDRESS) 180 return SET_ERROR(EINVAL); 181 if (len > VM_MAXUSER_ADDRESS - (uintptr_t)addr) 182 return SET_ERROR(EINVAL); 183 endaddr = (char *)addr + len; 184 185 newrp = kmem_alloc(sizeof(*newrp), KM_SLEEP); 186 newrp->ras_startaddr = addr; 187 newrp->ras_endaddr = endaddr; 188 error = 0; 189 nras = 0; 190 p = curproc; 191 192 mutex_enter(&p->p_auxlock); 193 for (rp = p->p_raslist; rp != NULL; rp = rp->ras_next) { 194 if (++nras >= ras_per_proc) { 195 error = SET_ERROR(EINVAL); 196 break; 197 } 198 if (addr < rp->ras_endaddr && endaddr > rp->ras_startaddr) { 199 error = SET_ERROR(EEXIST); 200 break; 201 } 202 } 203 if (rp == NULL) { 204 newrp->ras_next = p->p_raslist; 205 p->p_raslist = newrp; 206 ras_sync(); 207 mutex_exit(&p->p_auxlock); 208 } else { 209 mutex_exit(&p->p_auxlock); 210 kmem_free(newrp, sizeof(*newrp)); 211 } 212 213 return error; 214 } 215 216 /* 217 * Nuke the specified sequence. Both address and len must 218 * match, otherwise we return an error. 219 */ 220 static int 221 ras_purge(void *addr, size_t len) 222 { 223 struct ras *rp, **link; 224 proc_t *p; 225 226 p = curproc; 227 228 mutex_enter(&p->p_auxlock); 229 link = &p->p_raslist; 230 for (rp = *link; rp != NULL; link = &rp->ras_next, rp = *link) { 231 if (addr == rp->ras_startaddr && 232 (char *)rp->ras_endaddr - (char *)rp->ras_startaddr == len) 233 break; 234 } 235 if (rp != NULL) { 236 *link = rp->ras_next; 237 ras_sync(); 238 mutex_exit(&p->p_auxlock); 239 kmem_free(rp, sizeof(*rp)); 240 return 0; 241 } else { 242 mutex_exit(&p->p_auxlock); 243 return SET_ERROR(ESRCH); 244 } 245 } 246 247 #endif /* defined(__HAVE_RAS) */ 248 249 /*ARGSUSED*/ 250 int 251 sys_rasctl(struct lwp *l, const struct sys_rasctl_args *uap, register_t *retval) 252 { 253 #if defined(__HAVE_RAS) 254 /* { 255 syscallarg(void *) addr; 256 syscallarg(size_t) len; 257 syscallarg(int) op; 258 } */ 259 void *addr; 260 size_t len; 261 int op; 262 int error; 263 264 /* 265 * first, extract syscall args from the uap. 266 */ 267 268 addr = (void *)SCARG(uap, addr); 269 len = (size_t)SCARG(uap, len); 270 op = SCARG(uap, op); 271 272 DPRINTF(("sys_rasctl: p=%p addr=%p, len=%ld, op=0x%x\n", 273 curproc, addr, (long)len, op)); 274 275 switch (op) { 276 case RAS_INSTALL: 277 error = ras_install(addr, len); 278 break; 279 case RAS_PURGE: 280 error = ras_purge(addr, len); 281 break; 282 case RAS_PURGE_ALL: 283 error = ras_purgeall(); 284 break; 285 default: 286 error = SET_ERROR(EINVAL); 287 break; 288 } 289 290 return error; 291 #else 292 return SET_ERROR(EOPNOTSUPP); 293 #endif 294 } 295
Indexes created Sat Feb 21 01:20:28 UTC 2026