1 /* $NetBSD: kern_ras.c,v 1.42 2022/08/08 22:31:45 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 1.42 2022/08/08 22:31:45 riastradh Exp $"); 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/kernel.h> 38 #include <sys/kmem.h> 39 #include <sys/proc.h> 40 #include <sys/ras.h> 41 #include <sys/xcall.h> 42 #include <sys/syscallargs.h> 43 44 #include <uvm/uvm_extern.h> 45 46 #define MAX_RAS_PER_PROC 16 47 48 u_int ras_per_proc = MAX_RAS_PER_PROC; 49 50 #ifdef DEBUG 51 int ras_debug = 0; 52 #define DPRINTF(x) if (ras_debug) printf x 53 #else 54 #define DPRINTF(x) /* nothing */ 55 #endif 56 57 /* 58 * Force all CPUs through cpu_switchto(), waiting until complete. 59 * Context switching will drain the write buffer on the calling 60 * CPU. 61 */ 62 static void 63 ras_sync(void) 64 { 65 66 /* No need to sync if exiting or single threaded. */ 67 if (curproc->p_nlwps > 1 && ncpu > 1) { 68 xc_barrier(0); 69 } 70 } 71 72 /* 73 * Check the specified address to see if it is within the 74 * sequence. If it is found, we return the restart address, 75 * otherwise we return -1. If we do perform a restart, we 76 * mark the sequence as hit. 77 * 78 * No locking required: we disable preemption and ras_sync() 79 * guarantees that individual entries are valid while we still 80 * have visibility of them. 81 */ 82 void * 83 ras_lookup(struct proc *p, void *addr) 84 { 85 struct ras *rp; 86 void *startaddr; 87 lwp_t *l; 88 89 startaddr = (void *)-1; 90 l = curlwp; 91 92 KPREEMPT_DISABLE(l); 93 for (rp = p->p_raslist; rp != NULL; rp = rp->ras_next) { 94 if (addr > rp->ras_startaddr && addr < rp->ras_endaddr) { 95 startaddr = rp->ras_startaddr; 96 DPRINTF(("RAS hit: p=%p %p\n", p, addr)); 97 break; 98 } 99 } 100 KPREEMPT_ENABLE(l); 101 102 return startaddr; 103 } 104 105 /* 106 * During a fork, we copy all of the sequences from parent p1 to 107 * the child p2. 108 * 109 * No locking required as the parent must be paused. 110 */ 111 int 112 ras_fork(struct proc *p1, struct proc *p2) 113 { 114 struct ras *rp, *nrp; 115 116 for (rp = p1->p_raslist; rp != NULL; rp = rp->ras_next) { 117 nrp = kmem_alloc(sizeof(*nrp), KM_SLEEP); 118 nrp->ras_startaddr = rp->ras_startaddr; 119 nrp->ras_endaddr = rp->ras_endaddr; 120 nrp->ras_next = p2->p_raslist; 121 p2->p_raslist = nrp; 122 } 123 124 DPRINTF(("ras_fork: p1=%p, p2=%p\n", p1, p2)); 125 126 return 0; 127 } 128 129 /* 130 * Nuke all sequences for this process. 131 */ 132 int 133 ras_purgeall(void) 134 { 135 struct ras *rp, *nrp; 136 proc_t *p; 137 138 p = curproc; 139 140 if (p->p_raslist == NULL) 141 return 0; 142 143 mutex_enter(&p->p_auxlock); 144 if ((rp = p->p_raslist) != NULL) { 145 p->p_raslist = NULL; 146 ras_sync(); 147 for(; rp != NULL; rp = nrp) { 148 nrp = rp->ras_next; 149 kmem_free(rp, sizeof(*rp)); 150 } 151 } 152 mutex_exit(&p->p_auxlock); 153 154 return 0; 155 } 156 157 #if defined(__HAVE_RAS) 158 159 /* 160 * Install the new sequence. If it already exists, return 161 * an error. 162 */ 163 static int 164 ras_install(void *addr, size_t len) 165 { 166 struct ras *rp; 167 struct ras *newrp; 168 void *endaddr; 169 int nras, error; 170 proc_t *p; 171 172 if (len == 0) 173 return EINVAL; 174 175 if ((uintptr_t)addr < VM_MIN_ADDRESS || 176 (uintptr_t)addr > VM_MAXUSER_ADDRESS) 177 return EINVAL; 178 if (len > VM_MAXUSER_ADDRESS - (uintptr_t)addr) 179 return EINVAL; 180 endaddr = (char *)addr + len; 181 182 newrp = kmem_alloc(sizeof(*newrp), KM_SLEEP); 183 newrp->ras_startaddr = addr; 184 newrp->ras_endaddr = endaddr; 185 error = 0; 186 nras = 0; 187 p = curproc; 188 189 mutex_enter(&p->p_auxlock); 190 for (rp = p->p_raslist; rp != NULL; rp = rp->ras_next) { 191 if (++nras >= ras_per_proc) { 192 error = EINVAL; 193 break; 194 } 195 if (addr < rp->ras_endaddr && endaddr > rp->ras_startaddr) { 196 error = EEXIST; 197 break; 198 } 199 } 200 if (rp == NULL) { 201 newrp->ras_next = p->p_raslist; 202 p->p_raslist = newrp; 203 ras_sync(); 204 mutex_exit(&p->p_auxlock); 205 } else { 206 mutex_exit(&p->p_auxlock); 207 kmem_free(newrp, sizeof(*newrp)); 208 } 209 210 return error; 211 } 212 213 /* 214 * Nuke the specified sequence. Both address and len must 215 * match, otherwise we return an error. 216 */ 217 static int 218 ras_purge(void *addr, size_t len) 219 { 220 struct ras *rp, **link; 221 proc_t *p; 222 223 p = curproc; 224 225 mutex_enter(&p->p_auxlock); 226 link = &p->p_raslist; 227 for (rp = *link; rp != NULL; link = &rp->ras_next, rp = *link) { 228 if (addr == rp->ras_startaddr && 229 (char *)rp->ras_endaddr - (char *)rp->ras_startaddr == len) 230 break; 231 } 232 if (rp != NULL) { 233 *link = rp->ras_next; 234 ras_sync(); 235 mutex_exit(&p->p_auxlock); 236 kmem_free(rp, sizeof(*rp)); 237 return 0; 238 } else { 239 mutex_exit(&p->p_auxlock); 240 return ESRCH; 241 } 242 } 243 244 #endif /* defined(__HAVE_RAS) */ 245 246 /*ARGSUSED*/ 247 int 248 sys_rasctl(struct lwp *l, const struct sys_rasctl_args *uap, register_t *retval) 249 { 250 #if defined(__HAVE_RAS) 251 /* { 252 syscallarg(void *) addr; 253 syscallarg(size_t) len; 254 syscallarg(int) op; 255 } */ 256 void *addr; 257 size_t len; 258 int op; 259 int error; 260 261 /* 262 * first, extract syscall args from the uap. 263 */ 264 265 addr = (void *)SCARG(uap, addr); 266 len = (size_t)SCARG(uap, len); 267 op = SCARG(uap, op); 268 269 DPRINTF(("sys_rasctl: p=%p addr=%p, len=%ld, op=0x%x\n", 270 curproc, addr, (long)len, op)); 271 272 switch (op) { 273 case RAS_INSTALL: 274 error = ras_install(addr, len); 275 break; 276 case RAS_PURGE: 277 error = ras_purge(addr, len); 278 break; 279 case RAS_PURGE_ALL: 280 error = ras_purgeall(); 281 break; 282 default: 283 error = EINVAL; 284 break; 285 } 286 287 return (error); 288 #else 289 return (EOPNOTSUPP); 290 #endif 291 } 292
Indexes created Sat Sep 20 22:09:52 GMT 2025