1 /* $NetBSD: pmap_segtab.c,v 1.11 2019/10/20 07:22:51 skrll 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 1.11 2019/10/20 07:22:51 skrll 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 KASSERTMSG(pmap != pmap_kernel() || !pmap_md_direct_mapped_vaddr_p(va), 172 "pmap %p va %#" PRIxVADDR, pmap, va); 173 #ifdef _LP64 174 stp = stp->seg_seg[(va >> XSEGSHIFT) & (NSEGPG - 1)]; 175 if (stp == NULL) 176 return NULL; 177 #endif 178 179 return stp->seg_tab[(va >> SEGSHIFT) & (PMAP_SEGTABSIZE - 1)]; 180 } 181 182 pt_entry_t * 183 pmap_pte_lookup(pmap_t pmap, vaddr_t va) 184 { 185 pt_entry_t *pte = pmap_segmap(pmap, va); 186 if (pte == NULL) 187 return NULL; 188 189 return pte + ((va >> PGSHIFT) & (NPTEPG - 1)); 190 } 191 192 static void 193 pmap_segtab_free(pmap_segtab_t *stp) 194 { 195 /* 196 * Insert the segtab into the segtab freelist. 197 */ 198 mutex_spin_enter(&pmap_segtab_lock); 199 stp->seg_seg[0] = pmap_segtab_info.free_segtab; 200 pmap_segtab_info.free_segtab = stp; 201 SEGTAB_ADD(nput, 1); 202 mutex_spin_exit(&pmap_segtab_lock); 203 } 204 205 static void 206 pmap_segtab_release(pmap_t pmap, pmap_segtab_t **stp_p, bool free_stp, 207 pte_callback_t callback, uintptr_t flags, 208 vaddr_t va, vsize_t vinc) 209 { 210 pmap_segtab_t *stp = *stp_p; 211 212 for (size_t i = (va / vinc) & (PMAP_SEGTABSIZE - 1); 213 i < PMAP_SEGTABSIZE; 214 i++, va += vinc) { 215 #ifdef _LP64 216 if (vinc > NBSEG) { 217 if (stp->seg_seg[i] != NULL) { 218 pmap_segtab_release(pmap, &stp->seg_seg[i], 219 true, callback, flags, va, vinc / NSEGPG); 220 KASSERT(stp->seg_seg[i] == NULL); 221 } 222 continue; 223 } 224 #endif 225 KASSERT(vinc == NBSEG); 226 227 /* get pointer to segment map */ 228 pt_entry_t *pte = stp->seg_tab[i]; 229 if (pte == NULL) 230 continue; 231 232 /* 233 * If our caller want a callback, do so. 234 */ 235 if (callback != NULL) { 236 (*callback)(pmap, va, va + vinc, pte, flags); 237 } 238 #ifdef DEBUG 239 for (size_t j = 0; j < NPTEPG; j++) { 240 if (!pte_zero_p(pte[j])) 241 panic("%s: pte entry %p not 0 (%#"PRIxPTE")", 242 __func__, &pte[j], pte_value(pte[j])); 243 } 244 #endif 245 // PMAP_UNMAP_POOLPAGE should handle any VCA issues itself 246 paddr_t pa = PMAP_UNMAP_POOLPAGE((vaddr_t)pte); 247 struct vm_page *pg = PHYS_TO_VM_PAGE(pa); 248 #ifdef PMAP_PTP_CACHE 249 mutex_spin_enter(&pmap_segtab_lock); 250 LIST_INSERT_HEAD(&pmap_segtab_info.ptp_pgflist, pg, listq.list); 251 mutex_spin_exit(&pmap_segtab_lock); 252 #else 253 uvm_pagefree(pg); 254 #endif 255 256 stp->seg_tab[i] = NULL; 257 } 258 259 if (free_stp) { 260 pmap_check_stp(stp, __func__, 261 vinc == NBSEG ? "release seg" : "release xseg"); 262 pmap_segtab_free(stp); 263 *stp_p = NULL; 264 } 265 } 266 267 /* 268 * Create and return a physical map. 269 * 270 * If the size specified for the map 271 * is zero, the map is an actual physical 272 * map, and may be referenced by the 273 * hardware. 274 * 275 * If the size specified is non-zero, 276 * the map will be used in software only, and 277 * is bounded by that size. 278 */ 279 static pmap_segtab_t * 280 pmap_segtab_alloc(void) 281 { 282 pmap_segtab_t *stp; 283 bool found_on_freelist = false; 284 285 again: 286 mutex_spin_enter(&pmap_segtab_lock); 287 if (__predict_true((stp = pmap_segtab_info.free_segtab) != NULL)) { 288 pmap_segtab_info.free_segtab = stp->seg_seg[0]; 289 stp->seg_seg[0] = NULL; 290 SEGTAB_ADD(nget, 1); 291 found_on_freelist = true; 292 } 293 mutex_spin_exit(&pmap_segtab_lock); 294 295 if (__predict_false(stp == NULL)) { 296 struct vm_page * const stp_pg = pmap_pte_pagealloc(); 297 298 if (__predict_false(stp_pg == NULL)) { 299 /* 300 * XXX What else can we do? Could we deadlock here? 301 */ 302 uvm_wait("segtab"); 303 goto again; 304 } 305 SEGTAB_ADD(npage, 1); 306 const paddr_t stp_pa = VM_PAGE_TO_PHYS(stp_pg); 307 308 stp = (pmap_segtab_t *)PMAP_MAP_POOLPAGE(stp_pa); 309 const size_t n = NBPG / sizeof(*stp); 310 if (n > 1) { 311 /* 312 * link all the segtabs in this page together 313 */ 314 for (size_t i = 1; i < n - 1; i++) { 315 stp[i].seg_seg[0] = &stp[i+1]; 316 } 317 /* 318 * Now link the new segtabs into the free segtab list. 319 */ 320 mutex_spin_enter(&pmap_segtab_lock); 321 stp[n-1].seg_seg[0] = pmap_segtab_info.free_segtab; 322 pmap_segtab_info.free_segtab = stp + 1; 323 SEGTAB_ADD(nput, n - 1); 324 mutex_spin_exit(&pmap_segtab_lock); 325 } 326 } 327 328 pmap_check_stp(stp, __func__, 329 found_on_freelist ? "from free list" : "allocated"); 330 331 return stp; 332 } 333 334 /* 335 * Allocate the top segment table for the pmap. 336 */ 337 void 338 pmap_segtab_init(pmap_t pmap) 339 { 340 341 pmap->pm_segtab = pmap_segtab_alloc(); 342 } 343 344 /* 345 * Retire the given physical map from service. 346 * Should only be called if the map contains 347 * no valid mappings. 348 */ 349 void 350 pmap_segtab_destroy(pmap_t pmap, pte_callback_t func, uintptr_t flags) 351 { 352 if (pmap->pm_segtab == NULL) 353 return; 354 355 #ifdef _LP64 356 const vsize_t vinc = NBXSEG; 357 #else 358 const vsize_t vinc = NBSEG; 359 #endif 360 pmap_segtab_release(pmap, &pmap->pm_segtab, 361 func == NULL, func, flags, pmap->pm_minaddr, vinc); 362 } 363 364 /* 365 * Make a new pmap (vmspace) active for the given process. 366 */ 367 void 368 pmap_segtab_activate(struct pmap *pm, struct lwp *l) 369 { 370 if (l == curlwp) { 371 struct cpu_info * const ci = l->l_cpu; 372 KASSERT(pm == l->l_proc->p_vmspace->vm_map.pmap); 373 if (pm == pmap_kernel()) { 374 ci->ci_pmap_user_segtab = PMAP_INVALID_SEGTAB_ADDRESS; 375 #ifdef _LP64 376 ci->ci_pmap_user_seg0tab = PMAP_INVALID_SEGTAB_ADDRESS; 377 #endif 378 } else { 379 ci->ci_pmap_user_segtab = pm->pm_segtab; 380 #ifdef _LP64 381 ci->ci_pmap_user_seg0tab = pm->pm_segtab->seg_seg[0]; 382 #endif 383 } 384 } 385 } 386 387 /* 388 * Act on the given range of addresses from the specified map. 389 * 390 * It is assumed that the start and end are properly rounded to 391 * the page size. 392 */ 393 void 394 pmap_pte_process(pmap_t pmap, vaddr_t sva, vaddr_t eva, 395 pte_callback_t callback, uintptr_t flags) 396 { 397 #if 0 398 printf("%s: %p, %"PRIxVADDR", %"PRIxVADDR", %p, %"PRIxPTR"\n", 399 __func__, pmap, sva, eva, callback, flags); 400 #endif 401 while (sva < eva) { 402 vaddr_t lastseg_va = pmap_trunc_seg(sva) + NBSEG; 403 if (lastseg_va == 0 || lastseg_va > eva) 404 lastseg_va = eva; 405 406 /* 407 * If VA belongs to an unallocated segment, 408 * skip to the next segment boundary. 409 */ 410 pt_entry_t * const ptep = pmap_pte_lookup(pmap, sva); 411 if (ptep != NULL) { 412 /* 413 * Callback to deal with the ptes for this segment. 414 */ 415 (*callback)(pmap, sva, lastseg_va, ptep, flags); 416 } 417 /* 418 * In theory we could release pages with no entries, 419 * but that takes more effort than we want here. 420 */ 421 sva = lastseg_va; 422 } 423 } 424 425 /* 426 * Return a pointer for the pte that corresponds to the specified virtual 427 * address (va) in the target physical map, allocating if needed. 428 */ 429 pt_entry_t * 430 pmap_pte_reserve(pmap_t pmap, vaddr_t va, int flags) 431 { 432 pmap_segtab_t *stp = pmap->pm_segtab; 433 pt_entry_t *pte; 434 435 pte = pmap_pte_lookup(pmap, va); 436 if (__predict_false(pte == NULL)) { 437 #ifdef _LP64 438 pmap_segtab_t ** const stp_p = 439 &stp->seg_seg[(va >> XSEGSHIFT) & (NSEGPG - 1)]; 440 if (__predict_false((stp = *stp_p) == NULL)) { 441 pmap_segtab_t *nstp = pmap_segtab_alloc(); 442 #ifdef MULTIPROCESSOR 443 pmap_segtab_t *ostp = atomic_cas_ptr(stp_p, NULL, nstp); 444 if (__predict_false(ostp != NULL)) { 445 pmap_check_stp(nstp, __func__, "reserve"); 446 pmap_segtab_free(nstp); 447 nstp = ostp; 448 } 449 #else 450 *stp_p = nstp; 451 #endif /* MULTIPROCESSOR */ 452 stp = nstp; 453 } 454 KASSERT(stp == pmap->pm_segtab->seg_seg[(va >> XSEGSHIFT) & (NSEGPG - 1)]); 455 #endif /* _LP64 */ 456 struct vm_page *pg = NULL; 457 #ifdef PMAP_PTP_CACHE 458 mutex_spin_enter(&pmap_segtab_lock); 459 if ((pg = LIST_FIRST(&pmap_segtab_info.ptp_pgflist)) != NULL) { 460 LIST_REMOVE(pg, listq.list); 461 KASSERT(LIST_FIRST(&pmap_segtab_info.ptp_pgflist) != pg); 462 } 463 mutex_spin_exit(&pmap_segtab_lock); 464 #endif 465 if (pg == NULL) 466 pg = pmap_pte_pagealloc(); 467 if (pg == NULL) { 468 if (flags & PMAP_CANFAIL) 469 return NULL; 470 panic("%s: cannot allocate page table page " 471 "for va %" PRIxVADDR, __func__, va); 472 } 473 474 const paddr_t pa = VM_PAGE_TO_PHYS(pg); 475 pte = (pt_entry_t *)PMAP_MAP_POOLPAGE(pa); 476 pt_entry_t ** const pte_p = 477 &stp->seg_tab[(va >> SEGSHIFT) & (PMAP_SEGTABSIZE - 1)]; 478 #ifdef MULTIPROCESSOR 479 pt_entry_t *opte = atomic_cas_ptr(pte_p, NULL, pte); 480 /* 481 * If another thread allocated the segtab needed for this va 482 * free the page we just allocated. 483 */ 484 if (__predict_false(opte != NULL)) { 485 #ifdef PMAP_PTP_CACHE 486 mutex_spin_enter(&pmap_segtab_lock); 487 LIST_INSERT_HEAD(&pmap_segtab_info.ptp_pgflist, 488 pg, listq.list); 489 mutex_spin_exit(&pmap_segtab_lock); 490 #else 491 PMAP_UNMAP_POOLPAGE((vaddr_t)pte); 492 uvm_pagefree(pg); 493 #endif 494 pte = opte; 495 } 496 #else 497 *pte_p = pte; 498 #endif 499 KASSERT(pte == stp->seg_tab[(va >> SEGSHIFT) & (PMAP_SEGTABSIZE - 1)]); 500 501 #ifdef DEBUG 502 for (size_t i = 0; i < NPTEPG; i++) { 503 if (!pte_zero_p(pte[i])) 504 panic("%s: new segmap %p not empty @ %zu", 505 __func__, pte, i); 506 } 507 #endif 508 pte += (va >> PGSHIFT) & (NPTEPG - 1); 509 } 510 511 return pte; 512 } 513