1 /* $NetBSD: pmap_segtab.c,v 1.4 2016/11/23 03:30:53 mrg Exp $ */ 2 3 /*- 4 * Copyright (c) 1998, 2001 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 9 * NASA Ames Research Center and by Chris G. Demetriou. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 /* 34 * Copyright (c) 1992, 1993 35 * The Regents of the University of California. All rights reserved. 36 * 37 * This code is derived from software contributed to Berkeley by 38 * the Systems Programming Group of the University of Utah Computer 39 * Science Department and Ralph Campbell. 40 * 41 * Redistribution and use in source and binary forms, with or without 42 * modification, are permitted provided that the following conditions 43 * are met: 44 * 1. Redistributions of source code must retain the above copyright 45 * notice, this list of conditions and the following disclaimer. 46 * 2. Redistributions in binary form must reproduce the above copyright 47 * notice, this list of conditions and the following disclaimer in the 48 * documentation and/or other materials provided with the distribution. 49 * 3. Neither the name of the University nor the names of its contributors 50 * may be used to endorse or promote products derived from this software 51 * without specific prior written permission. 52 * 53 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 54 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 55 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 56 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 57 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 58 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 59 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 60 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 61 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 62 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 63 * SUCH DAMAGE. 64 * 65 * @(#)pmap.c 8.4 (Berkeley) 1/26/94 66 */ 67 68 #include <sys/cdefs.h> 69 70 __KERNEL_RCSID(0, "$NetBSD: pmap_segtab.c,v 1.4 2016/11/23 03:30:53 mrg Exp $"); 71 72 /* 73 * Manages physical address maps. 74 * 75 * In addition to hardware address maps, this 76 * module is called upon to provide software-use-only 77 * maps which may or may not be stored in the same 78 * form as hardware maps. These pseudo-maps are 79 * used to store intermediate results from copy 80 * operations to and from address spaces. 81 * 82 * Since the information managed by this module is 83 * also stored by the logical address mapping module, 84 * this module may throw away valid virtual-to-physical 85 * mappings at almost any time. However, invalidations 86 * of virtual-to-physical mappings must be done as 87 * requested. 88 * 89 * In order to cope with hardware architectures which 90 * make virtual-to-physical map invalidates expensive, 91 * this module may delay invalidate or reduced protection 92 * operations until such time as they are actually 93 * necessary. This module is given full information as 94 * to which processors are currently using which maps, 95 * and to when physical maps must be made correct. 96 */ 97 98 #define __PMAP_PRIVATE 99 100 #include "opt_multiprocessor.h" 101 102 #include <sys/param.h> 103 #include <sys/systm.h> 104 #include <sys/proc.h> 105 #include <sys/mutex.h> 106 #include <sys/atomic.h> 107 108 #include <uvm/uvm.h> 109 110 CTASSERT(NBPG >= sizeof(pmap_segtab_t)); 111 112 struct pmap_segtab_info { 113 pmap_segtab_t *free_segtab; /* free list kept locally */ 114 #ifdef DEBUG 115 uint32_t nget_segtab; 116 uint32_t nput_segtab; 117 uint32_t npage_segtab; 118 #define SEGTAB_ADD(n, v) (pmap_segtab_info.n ## _segtab += (v)) 119 #else 120 #define SEGTAB_ADD(n, v) ((void) 0) 121 #endif 122 #ifdef PMAP_PTP_CACHE 123 struct pgflist ptp_pgflist; /* Keep a list of idle page tables. */ 124 #endif 125 } pmap_segtab_info = { 126 #ifdef PMAP_PTP_CACHE 127 .ptp_pgflist = LIST_HEAD_INITIALIZER(pmap_segtab_info.ptp_pgflist), 128 #endif 129 }; 130 131 kmutex_t pmap_segtab_lock __cacheline_aligned; 132 133 static void 134 pmap_check_stp(pmap_segtab_t *stp, const char *caller, const char *why) 135 { 136 #ifdef DEBUG 137 for (size_t i = 0; i < PMAP_SEGTABSIZE; i++) { 138 if (stp->seg_tab[i] != 0) { 139 #ifdef DEBUG_NOISY 140 for (size_t j = i; j < PMAP_SEGTABSIZE; j++) 141 printf("%s: pm_segtab.seg_tab[%zu] = 0x%p\n", 142 caller, j, stp->seg_tab[j]); 143 #endif 144 panic("%s: pm_segtab.seg_tab[%zu] != 0 (0x%p): %s", 145 caller, i, stp->seg_tab[i], why); 146 } 147 } 148 #endif 149 } 150 151 static inline struct vm_page * 152 pmap_pte_pagealloc(void) 153 { 154 struct vm_page *pg; 155 156 pg = PMAP_ALLOC_POOLPAGE(UVM_PGA_ZERO|UVM_PGA_USERESERVE); 157 if (pg) { 158 #ifdef UVM_PAGE_TRKOWN 159 pg->owner_tag = NULL; 160 #endif 161 UVM_PAGE_OWN(pg, "pmap-ptp"); 162 } 163 164 return pg; 165 } 166 167 static inline pt_entry_t * 168 pmap_segmap(struct pmap *pmap, vaddr_t va) 169 { 170 pmap_segtab_t *stp = pmap->pm_segtab; 171 KASSERT(pmap != pmap_kernel() || !pmap_md_direct_mapped_vaddr_p(va)); 172 #ifdef _LP64 173 stp = stp->seg_seg[(va >> XSEGSHIFT) & (NSEGPG - 1)]; 174 if (stp == NULL) 175 return NULL; 176 #endif 177 178 return stp->seg_tab[(va >> SEGSHIFT) & (PMAP_SEGTABSIZE - 1)]; 179 } 180 181 pt_entry_t * 182 pmap_pte_lookup(pmap_t pmap, vaddr_t va) 183 { 184 pt_entry_t *pte = pmap_segmap(pmap, va); 185 if (pte == NULL) 186 return NULL; 187 188 return pte + ((va >> PGSHIFT) & (NPTEPG - 1)); 189 } 190 191 static void 192 pmap_segtab_free(pmap_segtab_t *stp) 193 { 194 /* 195 * Insert the the segtab into the segtab freelist. 196 */ 197 mutex_spin_enter(&pmap_segtab_lock); 198 stp->seg_seg[0] = pmap_segtab_info.free_segtab; 199 pmap_segtab_info.free_segtab = stp; 200 SEGTAB_ADD(nput, 1); 201 mutex_spin_exit(&pmap_segtab_lock); 202 } 203 204 static void 205 pmap_segtab_release(pmap_t pmap, pmap_segtab_t **stp_p, bool free_stp, 206 pte_callback_t callback, uintptr_t flags, 207 vaddr_t va, vsize_t vinc) 208 { 209 pmap_segtab_t *stp = *stp_p; 210 211 for (size_t i = (va / vinc) & (PMAP_SEGTABSIZE - 1); 212 i < PMAP_SEGTABSIZE; 213 i++, va += vinc) { 214 #ifdef _LP64 215 if (vinc > NBSEG) { 216 if (stp->seg_seg[i] != NULL) { 217 pmap_segtab_release(pmap, &stp->seg_seg[i], 218 true, callback, flags, va, vinc / NSEGPG); 219 KASSERT(stp->seg_seg[i] == NULL); 220 } 221 continue; 222 } 223 #endif 224 KASSERT(vinc == NBSEG); 225 226 /* get pointer to segment map */ 227 pt_entry_t *pte = stp->seg_tab[i]; 228 if (pte == NULL) 229 continue; 230 231 /* 232 * If our caller want a callback, do so. 233 */ 234 if (callback != NULL) { 235 (*callback)(pmap, va, va + vinc, pte, flags); 236 } 237 #ifdef DEBUG 238 for (size_t j = 0; j < NPTEPG; j++) { 239 if (!pte_zero_p(pte[j])) 240 panic("%s: pte entry %p not 0 (%#"PRIxPTE")", 241 __func__, &pte[j], pte_value(pte[j])); 242 } 243 #endif 244 // PMAP_UNMAP_POOLPAGE should handle any VCA issues itself 245 paddr_t pa = PMAP_UNMAP_POOLPAGE((vaddr_t)pte); 246 struct vm_page *pg = PHYS_TO_VM_PAGE(pa); 247 #ifdef PMAP_PTP_CACHE 248 mutex_spin_enter(&pmap_segtab_lock); 249 LIST_INSERT_HEAD(&pmap_segtab_info.ptp_pgflist, pg, listq.list); 250 mutex_spin_exit(&pmap_segtab_lock); 251 #else 252 uvm_pagefree(pg); 253 #endif 254 255 stp->seg_tab[i] = NULL; 256 } 257 258 if (free_stp) { 259 pmap_check_stp(stp, __func__, 260 vinc == NBSEG ? "release seg" : "release xseg"); 261 pmap_segtab_free(stp); 262 *stp_p = NULL; 263 } 264 } 265 266 /* 267 * Create and return a physical map. 268 * 269 * If the size specified for the map 270 * is zero, the map is an actual physical 271 * map, and may be referenced by the 272 * hardware. 273 * 274 * If the size specified is non-zero, 275 * the map will be used in software only, and 276 * is bounded by that size. 277 */ 278 static pmap_segtab_t * 279 pmap_segtab_alloc(void) 280 { 281 pmap_segtab_t *stp; 282 bool found_on_freelist = false; 283 284 again: 285 mutex_spin_enter(&pmap_segtab_lock); 286 if (__predict_true((stp = pmap_segtab_info.free_segtab) != NULL)) { 287 pmap_segtab_info.free_segtab = stp->seg_seg[0]; 288 stp->seg_seg[0] = NULL; 289 SEGTAB_ADD(nget, 1); 290 found_on_freelist = true; 291 } 292 mutex_spin_exit(&pmap_segtab_lock); 293 294 if (__predict_false(stp == NULL)) { 295 struct vm_page * const stp_pg = pmap_pte_pagealloc(); 296 297 if (__predict_false(stp_pg == NULL)) { 298 /* 299 * XXX What else can we do? Could we deadlock here? 300 */ 301 uvm_wait("pmap_create"); 302 goto again; 303 } 304 SEGTAB_ADD(npage, 1); 305 const paddr_t stp_pa = VM_PAGE_TO_PHYS(stp_pg); 306 307 stp = (pmap_segtab_t *)PMAP_MAP_POOLPAGE(stp_pa); 308 const size_t n = NBPG / sizeof(*stp); 309 if (n > 1) { 310 /* 311 * link all the segtabs in this page together 312 */ 313 for (size_t i = 1; i < n - 1; i++) { 314 stp[i].seg_seg[0] = &stp[i+1]; 315 } 316 /* 317 * Now link the new segtabs into the free segtab list. 318 */ 319 mutex_spin_enter(&pmap_segtab_lock); 320 stp[n-1].seg_seg[0] = pmap_segtab_info.free_segtab; 321 pmap_segtab_info.free_segtab = stp + 1; 322 SEGTAB_ADD(nput, n - 1); 323 mutex_spin_exit(&pmap_segtab_lock); 324 } 325 } 326 327 pmap_check_stp(stp, __func__, 328 found_on_freelist ? "from free list" : "allocated"); 329 330 return stp; 331 } 332 333 /* 334 * Allocate the top segment table for the pmap. 335 */ 336 void 337 pmap_segtab_init(pmap_t pmap) 338 { 339 340 pmap->pm_segtab = pmap_segtab_alloc(); 341 } 342 343 /* 344 * Retire the given physical map from service. 345 * Should only be called if the map contains 346 * no valid mappings. 347 */ 348 void 349 pmap_segtab_destroy(pmap_t pmap, pte_callback_t func, uintptr_t flags) 350 { 351 if (pmap->pm_segtab == NULL) 352 return; 353 354 #ifdef _LP64 355 const vsize_t vinc = NBXSEG; 356 #else 357 const vsize_t vinc = NBSEG; 358 #endif 359 pmap_segtab_release(pmap, &pmap->pm_segtab, 360 func == NULL, func, flags, pmap->pm_minaddr, vinc); 361 } 362 363 /* 364 * Make a new pmap (vmspace) active for the given process. 365 */ 366 void 367 pmap_segtab_activate(struct pmap *pm, struct lwp *l) 368 { 369 if (l == curlwp) { 370 struct cpu_info * const ci = l->l_cpu; 371 KASSERT(pm == l->l_proc->p_vmspace->vm_map.pmap); 372 if (pm == pmap_kernel()) { 373 ci->ci_pmap_user_segtab = PMAP_INVALID_SEGTAB_ADDRESS; 374 #ifdef _LP64 375 ci->ci_pmap_user_seg0tab = PMAP_INVALID_SEGTAB_ADDRESS; 376 #endif 377 } else { 378 ci->ci_pmap_user_segtab = pm->pm_segtab; 379 #ifdef _LP64 380 ci->ci_pmap_user_seg0tab = pm->pm_segtab->seg_seg[0]; 381 #endif 382 } 383 } 384 } 385 386 /* 387 * Act on the given range of addresses from the specified map. 388 * 389 * It is assumed that the start and end are properly rounded to 390 * the page size. 391 */ 392 void 393 pmap_pte_process(pmap_t pmap, vaddr_t sva, vaddr_t eva, 394 pte_callback_t callback, uintptr_t flags) 395 { 396 #if 0 397 printf("%s: %p, %"PRIxVADDR", %"PRIxVADDR", %p, %"PRIxPTR"\n", 398 __func__, pmap, sva, eva, callback, flags); 399 #endif 400 while (sva < eva) { 401 vaddr_t lastseg_va = pmap_trunc_seg(sva) + NBSEG; 402 if (lastseg_va == 0 || lastseg_va > eva) 403 lastseg_va = eva; 404 405 /* 406 * If VA belongs to an unallocated segment, 407 * skip to the next segment boundary. 408 */ 409 pt_entry_t * const pte = pmap_pte_lookup(pmap, sva); 410 if (pte != NULL) { 411 /* 412 * Callback to deal with the ptes for this segment. 413 */ 414 (*callback)(pmap, sva, lastseg_va, pte, flags); 415 } 416 /* 417 * In theory we could release pages with no entries, 418 * but that takes more effort than we want here. 419 */ 420 sva = lastseg_va; 421 } 422 } 423 424 /* 425 * Return a pointer for the pte that corresponds to the specified virtual 426 * address (va) in the target physical map, allocating if needed. 427 */ 428 pt_entry_t * 429 pmap_pte_reserve(pmap_t pmap, vaddr_t va, int flags) 430 { 431 pmap_segtab_t *stp = pmap->pm_segtab; 432 pt_entry_t *pte; 433 434 pte = pmap_pte_lookup(pmap, va); 435 if (__predict_false(pte == NULL)) { 436 #ifdef _LP64 437 pmap_segtab_t ** const stp_p = 438 &stp->seg_seg[(va >> XSEGSHIFT) & (NSEGPG - 1)]; 439 if (__predict_false((stp = *stp_p) == NULL)) { 440 pmap_segtab_t *nstp = pmap_segtab_alloc(); 441 #ifdef MULTIPROCESSOR 442 pmap_segtab_t *ostp = atomic_cas_ptr(stp_p, NULL, nstp); 443 if (__predict_false(ostp != NULL)) { 444 pmap_check_stp(nstp, __func__, "reserve"); 445 pmap_segtab_free(nstp); 446 nstp = ostp; 447 } 448 #else 449 *stp_p = nstp; 450 #endif /* MULTIPROCESSOR */ 451 stp = nstp; 452 } 453 KASSERT(stp == pmap->pm_segtab->seg_seg[(va >> XSEGSHIFT) & (NSEGPG - 1)]); 454 #endif /* _LP64 */ 455 struct vm_page *pg = NULL; 456 #ifdef PMAP_PTP_CACHE 457 mutex_spin_enter(&pmap_segtab_lock); 458 if ((pg = LIST_FIRST(&pmap_segtab_info.ptp_pgflist)) != NULL) { 459 LIST_REMOVE(pg, listq.list); 460 KASSERT(LIST_FIRST(&pmap_segtab_info.ptp_pgflist) != pg); 461 } 462 mutex_spin_exit(&pmap_segtab_lock); 463 #endif 464 if (pg == NULL) 465 pg = pmap_pte_pagealloc(); 466 if (pg == NULL) { 467 if (flags & PMAP_CANFAIL) 468 return NULL; 469 panic("%s: cannot allocate page table page " 470 "for va %" PRIxVADDR, __func__, va); 471 } 472 473 const paddr_t pa = VM_PAGE_TO_PHYS(pg); 474 pte = (pt_entry_t *)PMAP_MAP_POOLPAGE(pa); 475 pt_entry_t ** const pte_p = 476 &stp->seg_tab[(va >> SEGSHIFT) & (PMAP_SEGTABSIZE - 1)]; 477 #ifdef MULTIPROCESSOR 478 pt_entry_t *opte = atomic_cas_ptr(pte_p, NULL, pte); 479 /* 480 * If another thread allocated the segtab needed for this va 481 * free the page we just allocated. 482 */ 483 if (__predict_false(opte != NULL)) { 484 #ifdef PMAP_PTP_CACHE 485 mutex_spin_enter(&pmap_segtab_lock); 486 LIST_INSERT_HEAD(&pmap_segtab_info.ptp_pgflist, 487 pg, listq.list); 488 mutex_spin_exit(&pmap_segtab_lock); 489 #else 490 PMAP_UNMAP_POOLPAGE((vaddr_t)pte); 491 uvm_pagefree(pg); 492 #endif 493 pte = opte; 494 } 495 #else 496 *pte_p = pte; 497 #endif 498 KASSERT(pte == stp->seg_tab[(va >> SEGSHIFT) & (PMAP_SEGTABSIZE - 1)]); 499 500 #ifdef DEBUG 501 for (size_t i = 0; i < NPTEPG; i++) { 502 if (!pte_zero_p(pte[i])) 503 panic("%s: new segmap %p not empty @ %zu", 504 __func__, pte, i); 505 } 506 #endif 507 pte += (va >> PGSHIFT) & (NPTEPG - 1); 508 } 509 510 return pte; 511 } 512