1 /* $OpenBSD: uvm_glue.c,v 1.47 2007/05/26 20:26:51 pedro Exp $ */ 2 /* $NetBSD: uvm_glue.c,v 1.44 2001/02/06 19:54:44 eeh Exp $ */ 3 4 /* 5 * Copyright (c) 1997 Charles D. Cranor and Washington University. 6 * Copyright (c) 1991, 1993, The Regents of the University of California. 7 * 8 * All rights reserved. 9 * 10 * This code is derived from software contributed to Berkeley by 11 * The Mach Operating System project at Carnegie-Mellon University. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. All advertising materials mentioning features or use of this software 22 * must display the following acknowledgement: 23 * This product includes software developed by Charles D. Cranor, 24 * Washington University, the University of California, Berkeley and 25 * its contributors. 26 * 4. Neither the name of the University nor the names of its contributors 27 * may be used to endorse or promote products derived from this software 28 * without specific prior written permission. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 33 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 40 * SUCH DAMAGE. 41 * 42 * @(#)vm_glue.c 8.6 (Berkeley) 1/5/94 43 * from: Id: uvm_glue.c,v 1.1.2.8 1998/02/07 01:16:54 chs Exp 44 * 45 * 46 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 47 * All rights reserved. 48 * 49 * Permission to use, copy, modify and distribute this software and 50 * its documentation is hereby granted, provided that both the copyright 51 * notice and this permission notice appear in all copies of the 52 * software, derivative works or modified versions, and any portions 53 * thereof, and that both notices appear in supporting documentation. 54 * 55 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 56 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 57 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 58 * 59 * Carnegie Mellon requests users of this software to return to 60 * 61 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 62 * School of Computer Science 63 * Carnegie Mellon University 64 * Pittsburgh PA 15213-3890 65 * 66 * any improvements or extensions that they make and grant Carnegie the 67 * rights to redistribute these changes. 68 */ 69 70 /* 71 * uvm_glue.c: glue functions 72 */ 73 74 #include <sys/param.h> 75 #include <sys/systm.h> 76 #include <sys/proc.h> 77 #include <sys/resourcevar.h> 78 #include <sys/buf.h> 79 #include <sys/user.h> 80 #ifdef SYSVSHM 81 #include <sys/shm.h> 82 #endif 83 #include <sys/sched.h> 84 85 #include <uvm/uvm.h> 86 87 #include <machine/cpu.h> 88 89 /* 90 * XXXCDC: do these really belong here? 91 */ 92 93 int readbuffers = 0; /* allow KGDB to read kern buffer pool */ 94 /* XXX: see uvm_kernacc */ 95 96 97 /* 98 * uvm_kernacc: can the kernel access a region of memory 99 * 100 * - called from malloc [DIAGNOSTIC], and /dev/kmem driver (mem.c) 101 */ 102 103 boolean_t 104 uvm_kernacc(addr, len, rw) 105 caddr_t addr; 106 size_t len; 107 int rw; 108 { 109 boolean_t rv; 110 vaddr_t saddr, eaddr; 111 vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE; 112 113 saddr = trunc_page((vaddr_t)addr); 114 eaddr = round_page((vaddr_t)addr + len); 115 vm_map_lock_read(kernel_map); 116 rv = uvm_map_checkprot(kernel_map, saddr, eaddr, prot); 117 vm_map_unlock_read(kernel_map); 118 119 return(rv); 120 } 121 122 #ifdef KGDB 123 /* 124 * Change protections on kernel pages from addr to addr+len 125 * (presumably so debugger can plant a breakpoint). 126 * 127 * We force the protection change at the pmap level. If we were 128 * to use vm_map_protect a change to allow writing would be lazily- 129 * applied meaning we would still take a protection fault, something 130 * we really don't want to do. It would also fragment the kernel 131 * map unnecessarily. We cannot use pmap_protect since it also won't 132 * enforce a write-enable request. Using pmap_enter is the only way 133 * we can ensure the change takes place properly. 134 */ 135 void 136 uvm_chgkprot(addr, len, rw) 137 caddr_t addr; 138 size_t len; 139 int rw; 140 { 141 vm_prot_t prot; 142 paddr_t pa; 143 vaddr_t sva, eva; 144 145 prot = rw == B_READ ? VM_PROT_READ : VM_PROT_READ|VM_PROT_WRITE; 146 eva = round_page((vaddr_t)addr + len); 147 for (sva = trunc_page((vaddr_t)addr); sva < eva; sva += PAGE_SIZE) { 148 /* 149 * Extract physical address for the page. 150 * We use a cheezy hack to differentiate physical 151 * page 0 from an invalid mapping, not that it 152 * really matters... 153 */ 154 if (pmap_extract(pmap_kernel(), sva, &pa) == FALSE) 155 panic("chgkprot: invalid page"); 156 pmap_enter(pmap_kernel(), sva, pa, prot, PMAP_WIRED); 157 } 158 pmap_update(pmap_kernel()); 159 } 160 #endif 161 162 /* 163 * uvm_vslock: wire user memory for I/O 164 * 165 * - called from physio and sys___sysctl 166 * - XXXCDC: consider nuking this (or making it a macro?) 167 */ 168 169 int 170 uvm_vslock(p, addr, len, access_type) 171 struct proc *p; 172 caddr_t addr; 173 size_t len; 174 vm_prot_t access_type; 175 { 176 vm_map_t map; 177 vaddr_t start, end; 178 int rv; 179 180 map = &p->p_vmspace->vm_map; 181 start = trunc_page((vaddr_t)addr); 182 end = round_page((vaddr_t)addr + len); 183 if (end <= start) 184 return (EINVAL); 185 186 rv = uvm_fault_wire(map, start, end, access_type); 187 188 return (rv); 189 } 190 191 /* 192 * uvm_vsunlock: unwire user memory wired by uvm_vslock() 193 * 194 * - called from physio and sys___sysctl 195 * - XXXCDC: consider nuking this (or making it a macro?) 196 */ 197 198 void 199 uvm_vsunlock(p, addr, len) 200 struct proc *p; 201 caddr_t addr; 202 size_t len; 203 { 204 vaddr_t start, end; 205 206 start = trunc_page((vaddr_t)addr); 207 end = round_page((vaddr_t)addr + len); 208 if (end <= start) 209 return; 210 211 uvm_fault_unwire(&p->p_vmspace->vm_map, start, end); 212 } 213 214 /* 215 * uvm_fork: fork a virtual address space 216 * 217 * - the address space is copied as per parent map's inherit values 218 * - a new "user" structure is allocated for the child process 219 * [filled in by MD layer...] 220 * - if specified, the child gets a new user stack described by 221 * stack and stacksize 222 * - NOTE: the kernel stack may be at a different location in the child 223 * process, and thus addresses of automatic variables may be invalid 224 * after cpu_fork returns in the child process. We do nothing here 225 * after cpu_fork returns. 226 * - XXXCDC: we need a way for this to return a failure value rather 227 * than just hang 228 */ 229 void 230 uvm_fork(p1, p2, shared, stack, stacksize, func, arg) 231 struct proc *p1, *p2; 232 boolean_t shared; 233 void *stack; 234 size_t stacksize; 235 void (*func)(void *); 236 void *arg; 237 { 238 struct user *up = p2->p_addr; 239 240 if (shared == TRUE) { 241 p2->p_vmspace = NULL; 242 uvmspace_share(p1, p2); /* share vmspace */ 243 } else 244 p2->p_vmspace = uvmspace_fork(p1->p_vmspace); /* fork vmspace */ 245 246 #ifdef PMAP_UAREA 247 /* Tell the pmap this is a u-area mapping */ 248 PMAP_UAREA((vaddr_t)up); 249 #endif 250 251 /* 252 * p_stats currently points at a field in the user struct. Copy 253 * parts of p_stats, and zero out the rest. 254 */ 255 p2->p_stats = &up->u_stats; 256 memset(&up->u_stats.pstat_startzero, 0, 257 ((caddr_t)&up->u_stats.pstat_endzero - 258 (caddr_t)&up->u_stats.pstat_startzero)); 259 memcpy(&up->u_stats.pstat_startcopy, &p1->p_stats->pstat_startcopy, 260 ((caddr_t)&up->u_stats.pstat_endcopy - 261 (caddr_t)&up->u_stats.pstat_startcopy)); 262 263 /* 264 * cpu_fork() copy and update the pcb, and make the child ready 265 * to run. If this is a normal user fork, the child will exit 266 * directly to user mode via child_return() on its first time 267 * slice and will not return here. If this is a kernel thread, 268 * the specified entry point will be executed. 269 */ 270 cpu_fork(p1, p2, stack, stacksize, func, arg); 271 } 272 273 /* 274 * uvm_exit: exit a virtual address space 275 * 276 * - the process passed to us is a dead (pre-zombie) process; we 277 * are running on a different context now (the reaper). 278 * - we must run in a separate thread because freeing the vmspace 279 * of the dead process may block. 280 */ 281 void 282 uvm_exit(struct proc *p) 283 { 284 uvmspace_free(p->p_vmspace); 285 uvm_km_free(kernel_map, (vaddr_t)p->p_addr, USPACE); 286 p->p_addr = NULL; 287 } 288 289 /* 290 * uvm_init_limit: init per-process VM limits 291 * 292 * - called for process 0 and then inherited by all others. 293 */ 294 void 295 uvm_init_limits(struct proc *p) 296 { 297 298 /* 299 * Set up the initial limits on process VM. Set the maximum 300 * resident set size to be all of (reasonably) available memory. 301 * This causes any single, large process to start random page 302 * replacement once it fills memory. 303 */ 304 305 p->p_rlimit[RLIMIT_STACK].rlim_cur = DFLSSIZ; 306 p->p_rlimit[RLIMIT_STACK].rlim_max = MAXSSIZ; 307 p->p_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ; 308 p->p_rlimit[RLIMIT_DATA].rlim_max = MAXDSIZ; 309 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(uvmexp.free); 310 } 311 312 #ifdef DEBUG 313 int enableswap = 1; 314 int swapdebug = 0; 315 #define SDB_FOLLOW 1 316 #define SDB_SWAPIN 2 317 #define SDB_SWAPOUT 4 318 #endif 319 320 /* 321 * uvm_scheduler: process zero main loop 322 * 323 * - if not enough memory, wake the pagedaemon and let it clear space. 324 */ 325 326 void 327 uvm_scheduler(void) 328 { 329 /* 330 * Nothing to do, back to sleep 331 */ 332 while (1) 333 tsleep(&proc0, PVM, "scheduler", 0); 334 } 335 336 /* 337 * swappable: is process "p" swappable? 338 */ 339 340 #define swappable(p) (((p)->p_flag & (P_SYSTEM | P_WEXIT)) == 0) 341 342 /* 343 * swapout_threads: find threads that can be swapped 344 * 345 * - called by the pagedaemon 346 * - try and swap at least one processs 347 * - processes that are sleeping or stopped for maxslp or more seconds 348 * are swapped... otherwise the longest-sleeping or stopped process 349 * is swapped, otherwise the longest resident process... 350 */ 351 void 352 uvm_swapout_threads(void) 353 { 354 struct proc *p; 355 struct proc *outp, *outp2; 356 int outpri, outpri2; 357 int didswap = 0; 358 extern int maxslp; 359 /* XXXCDC: should move off to uvmexp. or uvm., also in uvm_meter */ 360 361 #ifdef DEBUG 362 if (!enableswap) 363 return; 364 #endif 365 366 /* 367 * outp/outpri : stop/sleep process with largest sleeptime < maxslp 368 * outp2/outpri2: the longest resident process (its swap time) 369 */ 370 outp = outp2 = NULL; 371 outpri = outpri2 = 0; 372 LIST_FOREACH(p, &allproc, p_list) { 373 if (!swappable(p)) 374 continue; 375 switch (p->p_stat) { 376 case SRUN: 377 if (p->p_swtime > outpri2) { 378 outp2 = p; 379 outpri2 = p->p_swtime; 380 } 381 continue; 382 383 case SSLEEP: 384 case SSTOP: 385 if (p->p_slptime >= maxslp) { 386 pmap_collect(p->p_vmspace->vm_map.pmap); 387 didswap++; 388 } else if (p->p_slptime > outpri) { 389 outp = p; 390 outpri = p->p_slptime; 391 } 392 continue; 393 } 394 } 395 396 /* 397 * If we didn't get rid of any real duds, toss out the next most 398 * likely sleeping/stopped or running candidate. We only do this 399 * if we are real low on memory since we don't gain much by doing 400 * it. 401 */ 402 if (didswap == 0 && uvmexp.free <= atop(round_page(USPACE))) { 403 if ((p = outp) == NULL) 404 p = outp2; 405 #ifdef DEBUG 406 if (swapdebug & SDB_SWAPOUT) 407 printf("swapout_threads: no duds, try procp %p\n", p); 408 #endif 409 if (p) 410 pmap_collect(p->p_vmspace->vm_map.pmap); 411 } 412 } 413