1 /* 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * The Mach Operating System project at Carnegie-Mellon University. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * from: @(#)vm_glue.c 8.6 (Berkeley) 1/5/94 33 * 34 * 35 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 36 * All rights reserved. 37 * 38 * Permission to use, copy, modify and distribute this software and 39 * its documentation is hereby granted, provided that both the copyright 40 * notice and this permission notice appear in all copies of the 41 * software, derivative works or modified versions, and any portions 42 * thereof, and that both notices appear in supporting documentation. 43 * 44 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 45 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 46 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 47 * 48 * Carnegie Mellon requests users of this software to return to 49 * 50 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 51 * School of Computer Science 52 * Carnegie Mellon University 53 * Pittsburgh PA 15213-3890 54 * 55 * any improvements or extensions that they make and grant Carnegie the 56 * rights to redistribute these changes. 57 * 58 * $FreeBSD: src/sys/vm/vm_glue.c,v 1.94.2.4 2003/01/13 22:51:17 dillon Exp $ 59 */ 60 61 #include "opt_vm.h" 62 63 #include <sys/param.h> 64 #include <sys/systm.h> 65 #include <sys/proc.h> 66 #include <sys/resourcevar.h> 67 #include <sys/buf.h> 68 #include <sys/shm.h> 69 #include <sys/vmmeter.h> 70 #include <sys/sysctl.h> 71 72 #include <sys/kernel.h> 73 #include <sys/unistd.h> 74 75 #include <machine/limits.h> 76 77 #include <vm/vm.h> 78 #include <vm/vm_param.h> 79 #include <sys/lock.h> 80 #include <vm/pmap.h> 81 #include <vm/vm_map.h> 82 #include <vm/vm_page.h> 83 #include <vm/vm_page2.h> 84 #include <vm/vm_pageout.h> 85 #include <vm/vm_kern.h> 86 #include <vm/vm_extern.h> 87 88 /* 89 * THIS MUST BE THE LAST INITIALIZATION ITEM!!! 90 * 91 * Process 0 falls into this function, just loop on nothing. 92 */ 93 94 static void scheduler(void *); 95 SYSINIT(scheduler, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, scheduler, NULL); 96 97 #ifdef INVARIANTS 98 99 static int swap_debug = 0; 100 SYSCTL_INT(_vm, OID_AUTO, swap_debug, CTLFLAG_RW, &swap_debug, 0, ""); 101 102 #endif 103 104 /* 105 * No requirements. 106 */ 107 int 108 kernacc(c_caddr_t addr, int len, int rw) 109 { 110 boolean_t rv; 111 vm_offset_t saddr, eaddr; 112 vm_prot_t prot; 113 114 KASSERT((rw & (~VM_PROT_ALL)) == 0, 115 ("illegal ``rw'' argument to kernacc (%x)", rw)); 116 117 /* 118 * The globaldata space is not part of the kernel_map proper, 119 * check access separately. 120 */ 121 if (is_globaldata_space((vm_offset_t)addr, (vm_offset_t)(addr + len))) 122 return (TRUE); 123 124 /* 125 * Nominal kernel memory access - check access via kernel_map. 126 */ 127 if ((vm_offset_t)addr + len > vm_map_max(kernel_map) || 128 (vm_offset_t)addr + len < (vm_offset_t)addr) { 129 return (FALSE); 130 } 131 prot = rw; 132 saddr = trunc_page((vm_offset_t)addr); 133 eaddr = round_page((vm_offset_t)addr + len); 134 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot, FALSE); 135 136 return (rv == TRUE); 137 } 138 139 /* 140 * No requirements. 141 */ 142 int 143 useracc(c_caddr_t addr, int len, int rw) 144 { 145 boolean_t rv; 146 vm_prot_t prot; 147 vm_map_t map; 148 vm_offset_t wrap; 149 150 KASSERT((rw & (~VM_PROT_ALL)) == 0, 151 ("illegal ``rw'' argument to useracc (%x)", rw)); 152 prot = rw; 153 154 /* 155 * XXX - check separately to disallow access to user area and user 156 * page tables - they are in the map. 157 */ 158 wrap = (vm_offset_t)addr + len; 159 if (wrap > VM_MAX_USER_ADDRESS || wrap < (vm_offset_t)addr) { 160 return (FALSE); 161 } 162 map = &curproc->p_vmspace->vm_map; 163 vm_map_lock_read(map); 164 165 rv = vm_map_check_protection(map, trunc_page((vm_offset_t)addr), 166 round_page(wrap), prot, TRUE); 167 vm_map_unlock_read(map); 168 169 return (rv == TRUE); 170 } 171 172 /* 173 * No requirements. 174 */ 175 void 176 vslock(caddr_t addr, u_int len) 177 { 178 if (len) { 179 /* wire the pages */ 180 vm_map_kernel_wiring(&curproc->p_vmspace->vm_map, 181 trunc_page((vm_offset_t)addr), 182 round_page((vm_offset_t)addr + len), 183 0); 184 } 185 } 186 187 /* 188 * No requirements. 189 */ 190 void 191 vsunlock(caddr_t addr, u_int len) 192 { 193 if (len) { 194 /* unwire the pages */ 195 vm_map_kernel_wiring(&curproc->p_vmspace->vm_map, 196 trunc_page((vm_offset_t)addr), 197 round_page((vm_offset_t)addr + len), 198 KM_PAGEABLE); 199 } 200 } 201 202 /* 203 * Implement fork's actions on an address space. Here we arrange for the 204 * address space to be copied or referenced, allocate a user struct (pcb 205 * and kernel stack), then call the machine-dependent layer to fill those 206 * in and make the new process ready to run. The new process is set up 207 * so that it returns directly to user mode to avoid stack copying and 208 * relocation problems. 209 * 210 * If p2 is NULL and RFPROC is 0 we are just divorcing parts of the process 211 * from itself. 212 * 213 * Otherwise if p2 is NULL the new vmspace is not to be associated with any 214 * process or thread (so things like /dev/upmap and /dev/lpmap are not 215 * retained). 216 * 217 * Otherwise if p2 is not NULL then process specific mappings will be forked. 218 * If lp2 is not NULL only the thread-specific mappings for lp2 are forked, 219 * otherwise no thread-specific mappings are forked. 220 * 221 * No requirements. 222 */ 223 void 224 vm_fork(struct proc *p1, struct proc *p2, struct lwp *lp2, int flags) 225 { 226 if ((flags & RFPROC) == 0) { 227 /* 228 * Divorce the memory, if it is shared, essentially 229 * this changes shared memory amongst threads, into 230 * COW locally. 231 */ 232 if ((flags & RFMEM) == 0) { 233 if (vmspace_getrefs(p1->p_vmspace) > 1) { 234 vmspace_unshare(p1); 235 } 236 } 237 cpu_fork(ONLY_LWP_IN_PROC(p1), NULL, flags); 238 return; 239 } 240 241 if (flags & RFMEM) { 242 vmspace_ref(p1->p_vmspace); 243 p2->p_vmspace = p1->p_vmspace; 244 } 245 246 while (vm_paging_severe()) { 247 vm_wait(0); 248 } 249 250 if ((flags & RFMEM) == 0) { 251 p2->p_vmspace = vmspace_fork(p1->p_vmspace, p2, lp2); 252 253 pmap_pinit2(vmspace_pmap(p2->p_vmspace)); 254 255 if (p1->p_vmspace->vm_shm) 256 shmfork(p1, p2); 257 } 258 259 pmap_init_proc(p2); 260 } 261 262 /* 263 * Set default limits for VM system. Call during proc0's initialization. 264 * 265 * Called from the low level boot code only. 266 */ 267 void 268 vm_init_limits(struct proc *p) 269 { 270 int rss_limit; 271 272 /* 273 * Set up the initial limits on process VM. Set the maximum resident 274 * set size to be half of (reasonably) available memory. Since this 275 * is a soft limit, it comes into effect only when the system is out 276 * of memory - half of main memory helps to favor smaller processes, 277 * and reduces thrashing of the object cache. 278 */ 279 p->p_rlimit[RLIMIT_STACK].rlim_cur = dflssiz; 280 p->p_rlimit[RLIMIT_STACK].rlim_max = maxssiz; 281 p->p_rlimit[RLIMIT_DATA].rlim_cur = dfldsiz; 282 p->p_rlimit[RLIMIT_DATA].rlim_max = maxdsiz; 283 /* limit the limit to no less than 2MB */ 284 rss_limit = max(vmstats.v_free_count, 512); 285 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit); 286 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY; 287 } 288 289 /* 290 * process 0 winds up here after all kernel initialization sysinits have 291 * run. 292 */ 293 static void 294 scheduler(void *dummy) 295 { 296 for (;;) 297 tsleep(&proc0, 0, "idle", 0); 298 } 299