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 <sys/param.h> 62 #include <sys/systm.h> 63 #include <sys/proc.h> 64 #include <sys/resourcevar.h> 65 #include <sys/buf.h> 66 #include <sys/shm.h> 67 #include <sys/vmmeter.h> 68 #include <sys/sysctl.h> 69 70 #include <sys/kernel.h> 71 #include <sys/unistd.h> 72 73 #include <machine/limits.h> 74 75 #include <vm/vm.h> 76 #include <vm/vm_param.h> 77 #include <sys/lock.h> 78 #include <vm/pmap.h> 79 #include <vm/vm_map.h> 80 #include <vm/vm_page.h> 81 #include <vm/vm_page2.h> 82 #include <vm/vm_pageout.h> 83 #include <vm/vm_kern.h> 84 #include <vm/vm_extern.h> 85 86 /* 87 * THIS MUST BE THE LAST INITIALIZATION ITEM!!! 88 * 89 * Process 0 falls into this function, just loop on nothing. 90 */ 91 92 static void scheduler(void *); 93 SYSINIT(scheduler, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, scheduler, NULL); 94 95 #ifdef INVARIANTS 96 97 static int swap_debug = 0; 98 SYSCTL_INT(_vm, OID_AUTO, swap_debug, CTLFLAG_RW, &swap_debug, 0, ""); 99 100 #endif 101 102 /* 103 * No requirements. 104 */ 105 int 106 kernacc(c_caddr_t addr, int len, int rw) 107 { 108 boolean_t rv; 109 vm_offset_t saddr, eaddr; 110 vm_prot_t prot; 111 112 KASSERT((rw & (~VM_PROT_ALL)) == 0, 113 ("illegal ``rw'' argument to kernacc (%x)", rw)); 114 115 /* 116 * The globaldata space is not part of the kernel_map proper, 117 * check access separately. 118 */ 119 if (is_globaldata_space((vm_offset_t)addr, (vm_offset_t)(addr + len))) 120 return (TRUE); 121 122 /* 123 * Nominal kernel memory access - check access via kernel_map. 124 */ 125 if ((vm_offset_t)addr + len > vm_map_max(kernel_map) || 126 (vm_offset_t)addr + len < (vm_offset_t)addr) { 127 return (FALSE); 128 } 129 prot = rw; 130 saddr = trunc_page((vm_offset_t)addr); 131 eaddr = round_page((vm_offset_t)addr + len); 132 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot, FALSE); 133 134 return (rv == TRUE); 135 } 136 137 /* 138 * No requirements. 139 */ 140 int 141 useracc(c_caddr_t addr, int len, int rw) 142 { 143 boolean_t rv; 144 vm_prot_t prot; 145 vm_map_t map; 146 vm_offset_t wrap; 147 148 KASSERT((rw & (~VM_PROT_ALL)) == 0, 149 ("illegal ``rw'' argument to useracc (%x)", rw)); 150 prot = rw; 151 152 /* 153 * XXX - check separately to disallow access to user area and user 154 * page tables - they are in the map. 155 */ 156 wrap = (vm_offset_t)addr + len; 157 if (wrap > VM_MAX_USER_ADDRESS || wrap < (vm_offset_t)addr) { 158 return (FALSE); 159 } 160 map = &curproc->p_vmspace->vm_map; 161 vm_map_lock_read(map); 162 163 rv = vm_map_check_protection(map, trunc_page((vm_offset_t)addr), 164 round_page(wrap), prot, TRUE); 165 vm_map_unlock_read(map); 166 167 return (rv == TRUE); 168 } 169 170 /* 171 * No requirements. 172 */ 173 void 174 vslock(caddr_t addr, u_int len) 175 { 176 if (len) { 177 /* wire the pages */ 178 vm_map_kernel_wiring(&curproc->p_vmspace->vm_map, 179 trunc_page((vm_offset_t)addr), 180 round_page((vm_offset_t)addr + len), 181 0); 182 } 183 } 184 185 /* 186 * No requirements. 187 */ 188 void 189 vsunlock(caddr_t addr, u_int len) 190 { 191 if (len) { 192 /* unwire the pages */ 193 vm_map_kernel_wiring(&curproc->p_vmspace->vm_map, 194 trunc_page((vm_offset_t)addr), 195 round_page((vm_offset_t)addr + len), 196 KM_PAGEABLE); 197 } 198 } 199 200 /* 201 * Implement fork's actions on an address space. Here we arrange for the 202 * address space to be copied or referenced, allocate a user struct (pcb 203 * and kernel stack), then call the machine-dependent layer to fill those 204 * in and make the new process ready to run. The new process is set up 205 * so that it returns directly to user mode to avoid stack copying and 206 * relocation problems. 207 * 208 * If p2 is NULL and RFPROC is 0 we are just divorcing parts of the process 209 * from itself. 210 * 211 * Otherwise if p2 is NULL the new vmspace is not to be associated with any 212 * process or thread (so things like /dev/upmap and /dev/lpmap are not 213 * retained). 214 * 215 * Otherwise if p2 is not NULL then process specific mappings will be forked. 216 * If lp2 is not NULL only the thread-specific mappings for lp2 are forked, 217 * otherwise no thread-specific mappings are forked. 218 * 219 * No requirements. 220 */ 221 void 222 vm_fork(struct proc *p1, struct proc *p2, struct lwp *lp2, int flags) 223 { 224 if ((flags & RFPROC) == 0) { 225 /* 226 * Divorce the memory, if it is shared, essentially 227 * this changes shared memory amongst threads, into 228 * COW locally. 229 */ 230 if ((flags & RFMEM) == 0) { 231 if (vmspace_getrefs(p1->p_vmspace) > 1) { 232 vmspace_unshare(p1); 233 } 234 } 235 cpu_fork(ONLY_LWP_IN_PROC(p1), NULL, flags); 236 return; 237 } 238 239 if (flags & RFMEM) { 240 vmspace_ref(p1->p_vmspace); 241 p2->p_vmspace = p1->p_vmspace; 242 } 243 244 while (vm_paging_severe()) { 245 vm_wait(0); 246 } 247 248 if ((flags & RFMEM) == 0) { 249 p2->p_vmspace = vmspace_fork(p1->p_vmspace, p2, lp2); 250 251 pmap_pinit2(vmspace_pmap(p2->p_vmspace)); 252 253 if (p1->p_vmspace->vm_shm) 254 shmfork(p1, p2); 255 } 256 257 pmap_init_proc(p2); 258 } 259 260 /* 261 * Set default limits for VM system. Call during proc0's initialization. 262 * 263 * Called from the low level boot code only. 264 */ 265 void 266 vm_init_limits(struct proc *p) 267 { 268 int rss_limit; 269 270 /* 271 * Set up the initial limits on process VM. Set the maximum resident 272 * set size to be half of (reasonably) available memory. Since this 273 * is a soft limit, it comes into effect only when the system is out 274 * of memory - half of main memory helps to favor smaller processes, 275 * and reduces thrashing of the object cache. 276 */ 277 p->p_rlimit[RLIMIT_STACK].rlim_cur = dflssiz; 278 p->p_rlimit[RLIMIT_STACK].rlim_max = maxssiz; 279 p->p_rlimit[RLIMIT_DATA].rlim_cur = dfldsiz; 280 p->p_rlimit[RLIMIT_DATA].rlim_max = maxdsiz; 281 /* limit the limit to no less than 2MB */ 282 rss_limit = max(vmstats.v_free_count, 512); 283 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit); 284 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY; 285 } 286 287 /* 288 * process 0 winds up here after all kernel initialization sysinits have 289 * run. 290 */ 291 static void 292 scheduler(void *dummy) 293 { 294 for (;;) 295 tsleep(&proc0, 0, "idle", 0); 296 } 297