1 /* $OpenBSD: uvm_glue.c,v 1.58 2011/04/15 21:47:24 oga 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 * uvm_kernacc: can the kernel access a region of memory 91 * 92 * - called from malloc [DIAGNOSTIC], and /dev/kmem driver (mem.c) 93 */ 94 95 boolean_t 96 uvm_kernacc(caddr_t addr, size_t len, int rw) 97 { 98 boolean_t rv; 99 vaddr_t saddr, eaddr; 100 vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE; 101 102 saddr = trunc_page((vaddr_t)addr); 103 eaddr = round_page((vaddr_t)addr + len); 104 vm_map_lock_read(kernel_map); 105 rv = uvm_map_checkprot(kernel_map, saddr, eaddr, prot); 106 vm_map_unlock_read(kernel_map); 107 108 return(rv); 109 } 110 111 #ifdef KGDB 112 /* 113 * Change protections on kernel pages from addr to addr+len 114 * (presumably so debugger can plant a breakpoint). 115 * 116 * We force the protection change at the pmap level. If we were 117 * to use vm_map_protect a change to allow writing would be lazily- 118 * applied meaning we would still take a protection fault, something 119 * we really don't want to do. It would also fragment the kernel 120 * map unnecessarily. We cannot use pmap_protect since it also won't 121 * enforce a write-enable request. Using pmap_enter is the only way 122 * we can ensure the change takes place properly. 123 */ 124 void 125 uvm_chgkprot(caddr_t addr, size_t len, int rw) 126 { 127 vm_prot_t prot; 128 paddr_t pa; 129 vaddr_t sva, eva; 130 131 prot = rw == B_READ ? VM_PROT_READ : VM_PROT_READ|VM_PROT_WRITE; 132 eva = round_page((vaddr_t)addr + len); 133 for (sva = trunc_page((vaddr_t)addr); sva < eva; sva += PAGE_SIZE) { 134 /* 135 * Extract physical address for the page. 136 * We use a cheezy hack to differentiate physical 137 * page 0 from an invalid mapping, not that it 138 * really matters... 139 */ 140 if (pmap_extract(pmap_kernel(), sva, &pa) == FALSE) 141 panic("chgkprot: invalid page"); 142 pmap_enter(pmap_kernel(), sva, pa, prot, PMAP_WIRED); 143 } 144 pmap_update(pmap_kernel()); 145 } 146 #endif 147 148 /* 149 * uvm_vslock: wire user memory for I/O 150 * 151 * - called from physio and sys___sysctl 152 */ 153 154 int 155 uvm_vslock(struct proc *p, caddr_t addr, size_t len, vm_prot_t access_type) 156 { 157 struct vm_map *map; 158 vaddr_t start, end; 159 int rv; 160 161 map = &p->p_vmspace->vm_map; 162 start = trunc_page((vaddr_t)addr); 163 end = round_page((vaddr_t)addr + len); 164 if (end <= start) 165 return (EINVAL); 166 167 rv = uvm_fault_wire(map, start, end, access_type); 168 169 return (rv); 170 } 171 172 /* 173 * uvm_vsunlock: unwire user memory wired by uvm_vslock() 174 * 175 * - called from physio and sys___sysctl 176 */ 177 178 void 179 uvm_vsunlock(struct proc *p, caddr_t addr, size_t len) 180 { 181 vaddr_t start, end; 182 183 start = trunc_page((vaddr_t)addr); 184 end = round_page((vaddr_t)addr + len); 185 if (end <= start) 186 return; 187 188 uvm_fault_unwire(&p->p_vmspace->vm_map, start, end); 189 } 190 191 /* 192 * uvm_vslock_device: wire user memory, make sure it's device reachable 193 * and bounce if necessary. 194 * Always bounces for now. 195 */ 196 int 197 uvm_vslock_device(struct proc *p, void *addr, size_t len, 198 vm_prot_t access_type, void **retp) 199 { 200 struct vm_page *pg; 201 struct pglist pgl; 202 int npages; 203 vaddr_t start, end, off; 204 vaddr_t sva, va; 205 vsize_t sz; 206 int error, i; 207 208 start = trunc_page((vaddr_t)addr); 209 end = round_page((vaddr_t)addr + len); 210 sz = end - start; 211 off = (vaddr_t)addr - start; 212 if (end <= start) 213 return (EINVAL); 214 215 if ((error = uvm_fault_wire(&p->p_vmspace->vm_map, start, end, 216 access_type))) { 217 return (error); 218 } 219 220 npages = atop(sz); 221 for (i = 0; i < npages; i++) { 222 paddr_t pa; 223 224 if (!pmap_extract(p->p_vmspace->vm_map.pmap, 225 start + ptoa(i), &pa)) { 226 error = EFAULT; 227 goto out_unwire; 228 } 229 if (!PADDR_IS_DMA_REACHABLE(pa)) 230 break; 231 } 232 if (i == npages) { 233 *retp = NULL; 234 return (0); 235 } 236 237 if ((va = uvm_km_valloc(kernel_map, sz)) == 0) { 238 error = ENOMEM; 239 goto out_unwire; 240 } 241 sva = va; 242 243 TAILQ_INIT(&pgl); 244 error = uvm_pglistalloc(npages * PAGE_SIZE, dma_constraint.ucr_low, 245 dma_constraint.ucr_high, 0, 0, &pgl, npages, UVM_PLA_WAITOK); 246 if (error) 247 goto out_unmap; 248 249 while ((pg = TAILQ_FIRST(&pgl)) != NULL) { 250 TAILQ_REMOVE(&pgl, pg, pageq); 251 pmap_kenter_pa(va, VM_PAGE_TO_PHYS(pg), 252 VM_PROT_READ|VM_PROT_WRITE); 253 va += PAGE_SIZE; 254 } 255 pmap_update(pmap_kernel()); 256 KASSERT(va == sva + sz); 257 *retp = (void *)(sva + off); 258 259 if ((error = copyin(addr, *retp, len)) == 0) 260 return 0; 261 262 uvm_km_pgremove_intrsafe(sva, sva + sz); 263 pmap_kremove(sva, sz); 264 pmap_update(pmap_kernel()); 265 out_unmap: 266 uvm_km_free(kernel_map, sva, sz); 267 out_unwire: 268 uvm_fault_unwire(&p->p_vmspace->vm_map, start, end); 269 return (error); 270 } 271 272 void 273 uvm_vsunlock_device(struct proc *p, void *addr, size_t len, void *map) 274 { 275 vaddr_t start, end; 276 vaddr_t kva; 277 vsize_t sz; 278 279 start = trunc_page((vaddr_t)addr); 280 end = round_page((vaddr_t)addr + len); 281 sz = end - start; 282 if (end <= start) 283 return; 284 285 if (map) 286 copyout(map, addr, len); 287 uvm_fault_unwire(&p->p_vmspace->vm_map, start, end); 288 289 if (!map) 290 return; 291 292 kva = trunc_page((vaddr_t)map); 293 uvm_km_pgremove_intrsafe(kva, kva + sz); 294 pmap_kremove(kva, sz); 295 pmap_update(pmap_kernel()); 296 uvm_km_free(kernel_map, kva, sz); 297 } 298 299 /* 300 * uvm_fork: fork a virtual address space 301 * 302 * - the address space is copied as per parent map's inherit values 303 * - a new "user" structure is allocated for the child process 304 * [filled in by MD layer...] 305 * - if specified, the child gets a new user stack described by 306 * stack and stacksize 307 * - NOTE: the kernel stack may be at a different location in the child 308 * process, and thus addresses of automatic variables may be invalid 309 * after cpu_fork returns in the child process. We do nothing here 310 * after cpu_fork returns. 311 * - XXXCDC: we need a way for this to return a failure value rather 312 * than just hang 313 */ 314 void 315 uvm_fork(struct proc *p1, struct proc *p2, boolean_t shared, void *stack, 316 size_t stacksize, void (*func)(void *), void * arg) 317 { 318 struct user *up = p2->p_addr; 319 320 if (shared == TRUE) { 321 p2->p_vmspace = NULL; 322 uvmspace_share(p1, p2); /* share vmspace */ 323 } else 324 p2->p_vmspace = uvmspace_fork(p1->p_vmspace); /* fork vmspace */ 325 326 #ifdef PMAP_UAREA 327 /* Tell the pmap this is a u-area mapping */ 328 PMAP_UAREA((vaddr_t)up); 329 #endif 330 331 /* 332 * p_stats currently points at a field in the user struct. Copy 333 * parts of p_stats, and zero out the rest. 334 */ 335 p2->p_stats = &up->u_stats; 336 memset(&up->u_stats.pstat_startzero, 0, 337 ((caddr_t)&up->u_stats.pstat_endzero - 338 (caddr_t)&up->u_stats.pstat_startzero)); 339 memcpy(&up->u_stats.pstat_startcopy, &p1->p_stats->pstat_startcopy, 340 ((caddr_t)&up->u_stats.pstat_endcopy - 341 (caddr_t)&up->u_stats.pstat_startcopy)); 342 343 /* 344 * cpu_fork() copy and update the pcb, and make the child ready 345 * to run. If this is a normal user fork, the child will exit 346 * directly to user mode via child_return() on its first time 347 * slice and will not return here. If this is a kernel thread, 348 * the specified entry point will be executed. 349 */ 350 cpu_fork(p1, p2, stack, stacksize, func, arg); 351 } 352 353 /* 354 * uvm_exit: exit a virtual address space 355 * 356 * - the process passed to us is a dead (pre-zombie) process; we 357 * are running on a different context now (the reaper). 358 * - we must run in a separate thread because freeing the vmspace 359 * of the dead process may block. 360 */ 361 void 362 uvm_exit(struct proc *p) 363 { 364 uvmspace_free(p->p_vmspace); 365 p->p_vmspace = NULL; 366 uvm_km_free(kernel_map, (vaddr_t)p->p_addr, USPACE); 367 p->p_addr = NULL; 368 } 369 370 /* 371 * uvm_init_limit: init per-process VM limits 372 * 373 * - called for process 0 and then inherited by all others. 374 */ 375 void 376 uvm_init_limits(struct proc *p) 377 { 378 379 /* 380 * Set up the initial limits on process VM. Set the maximum 381 * resident set size to be all of (reasonably) available memory. 382 * This causes any single, large process to start random page 383 * replacement once it fills memory. 384 */ 385 386 p->p_rlimit[RLIMIT_STACK].rlim_cur = DFLSSIZ; 387 p->p_rlimit[RLIMIT_STACK].rlim_max = MAXSSIZ; 388 p->p_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ; 389 p->p_rlimit[RLIMIT_DATA].rlim_max = MAXDSIZ; 390 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(uvmexp.free); 391 } 392 393 #ifdef DEBUG 394 int enableswap = 1; 395 int swapdebug = 0; 396 #define SDB_FOLLOW 1 397 #define SDB_SWAPIN 2 398 #define SDB_SWAPOUT 4 399 #endif 400 401 /* 402 * swappable: is process "p" swappable? 403 */ 404 405 #define swappable(p) (((p)->p_flag & (P_SYSTEM | P_WEXIT)) == 0) 406 407 /* 408 * swapout_threads: find threads that can be swapped 409 * 410 * - called by the pagedaemon 411 * - try and swap at least one processs 412 * - processes that are sleeping or stopped for maxslp or more seconds 413 * are swapped... otherwise the longest-sleeping or stopped process 414 * is swapped, otherwise the longest resident process... 415 */ 416 void 417 uvm_swapout_threads(void) 418 { 419 struct proc *p; 420 struct proc *outp, *outp2; 421 int outpri, outpri2; 422 int didswap = 0; 423 extern int maxslp; 424 /* XXXCDC: should move off to uvmexp. or uvm., also in uvm_meter */ 425 426 #ifdef DEBUG 427 if (!enableswap) 428 return; 429 #endif 430 431 /* 432 * outp/outpri : stop/sleep process with largest sleeptime < maxslp 433 * outp2/outpri2: the longest resident process (its swap time) 434 */ 435 outp = outp2 = NULL; 436 outpri = outpri2 = 0; 437 LIST_FOREACH(p, &allproc, p_list) { 438 if (!swappable(p)) 439 continue; 440 switch (p->p_stat) { 441 case SRUN: 442 if (p->p_swtime > outpri2) { 443 outp2 = p; 444 outpri2 = p->p_swtime; 445 } 446 continue; 447 448 case SSLEEP: 449 case SSTOP: 450 if (p->p_slptime >= maxslp) { 451 pmap_collect(p->p_vmspace->vm_map.pmap); 452 didswap++; 453 } else if (p->p_slptime > outpri) { 454 outp = p; 455 outpri = p->p_slptime; 456 } 457 continue; 458 } 459 } 460 461 /* 462 * If we didn't get rid of any real duds, toss out the next most 463 * likely sleeping/stopped or running candidate. We only do this 464 * if we are real low on memory since we don't gain much by doing 465 * it. 466 */ 467 if (didswap == 0 && uvmexp.free <= atop(round_page(USPACE))) { 468 if ((p = outp) == NULL) 469 p = outp2; 470 #ifdef DEBUG 471 if (swapdebug & SDB_SWAPOUT) 472 printf("swapout_threads: no duds, try procp %p\n", p); 473 #endif 474 if (p) 475 pmap_collect(p->p_vmspace->vm_map.pmap); 476 } 477 } 478 479 /* 480 * uvm_atopg: convert KVAs back to their page structures. 481 */ 482 struct vm_page * 483 uvm_atopg(vaddr_t kva) 484 { 485 struct vm_page *pg; 486 paddr_t pa; 487 boolean_t rv; 488 489 rv = pmap_extract(pmap_kernel(), kva, &pa); 490 KASSERT(rv); 491 pg = PHYS_TO_VM_PAGE(pa); 492 KASSERT(pg != NULL); 493 return (pg); 494 } 495