1 /* $NetBSD: pmap.h,v 1.55 2001/04/22 23:19:27 thorpej Exp $ */ 2 3 /* 4 * 5 * Copyright (c) 1997 Charles D. Cranor and Washington University. 6 * All rights reserved. 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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgment: 18 * This product includes software developed by Charles D. Cranor and 19 * Washington University. 20 * 4. The name of the author may not be used to endorse or promote products 21 * derived from this software without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /* 36 * pmap.h: see pmap.c for the history of this pmap module. 37 */ 38 39 #ifndef _I386_PMAP_H_ 40 #define _I386_PMAP_H_ 41 42 #if defined(_KERNEL) && !defined(_LKM) 43 #include "opt_user_ldt.h" 44 #include "opt_largepages.h" 45 #endif 46 47 #include <machine/cpufunc.h> 48 #include <machine/pte.h> 49 #include <machine/segments.h> 50 #include <uvm/uvm_object.h> 51 52 /* 53 * see pte.h for a description of i386 MMU terminology and hardware 54 * interface. 55 * 56 * a pmap describes a processes' 4GB virtual address space. this 57 * virtual address space can be broken up into 1024 4MB regions which 58 * are described by PDEs in the PDP. the PDEs are defined as follows: 59 * 60 * (ranges are inclusive -> exclusive, just like vm_map_entry start/end) 61 * (the following assumes that KERNBASE is 0xc0000000) 62 * 63 * PDE#s VA range usage 64 * 0->767 0x0 -> 0xbfc00000 user address space, note that the 65 * max user address is 0xbfbfe000 66 * the final two pages in the last 4MB 67 * used to be reserved for the UAREA 68 * but now are no longer used 69 * 768 0xbfc00000-> recursive mapping of PDP (used for 70 * 0xc0000000 linear mapping of PTPs) 71 * 768->1023 0xc0000000-> kernel address space (constant 72 * 0xffc00000 across all pmap's/processes) 73 * 1023 0xffc00000-> "alternate" recursive PDP mapping 74 * <end> (for other pmaps) 75 * 76 * 77 * note: a recursive PDP mapping provides a way to map all the PTEs for 78 * a 4GB address space into a linear chunk of virtual memory. in other 79 * words, the PTE for page 0 is the first int mapped into the 4MB recursive 80 * area. the PTE for page 1 is the second int. the very last int in the 81 * 4MB range is the PTE that maps VA 0xffffe000 (the last page in a 4GB 82 * address). 83 * 84 * all pmap's PD's must have the same values in slots 768->1023 so that 85 * the kernel is always mapped in every process. these values are loaded 86 * into the PD at pmap creation time. 87 * 88 * at any one time only one pmap can be active on a processor. this is 89 * the pmap whose PDP is pointed to by processor register %cr3. this pmap 90 * will have all its PTEs mapped into memory at the recursive mapping 91 * point (slot #767 as show above). when the pmap code wants to find the 92 * PTE for a virtual address, all it has to do is the following: 93 * 94 * address of PTE = (767 * 4MB) + (VA / NBPG) * sizeof(pt_entry_t) 95 * = 0xbfc00000 + (VA / 4096) * 4 96 * 97 * what happens if the pmap layer is asked to perform an operation 98 * on a pmap that is not the one which is currently active? in that 99 * case we take the PA of the PDP of non-active pmap and put it in 100 * slot 1023 of the active pmap. this causes the non-active pmap's 101 * PTEs to get mapped in the final 4MB of the 4GB address space 102 * (e.g. starting at 0xffc00000). 103 * 104 * the following figure shows the effects of the recursive PDP mapping: 105 * 106 * PDP (%cr3) 107 * +----+ 108 * | 0| -> PTP#0 that maps VA 0x0 -> 0x400000 109 * | | 110 * | | 111 * | 767| -> points back to PDP (%cr3) mapping VA 0xbfc00000 -> 0xc0000000 112 * | 768| -> first kernel PTP (maps 0xc0000000 -> 0xf0400000) 113 * | | 114 * |1023| -> points to alternate pmap's PDP (maps 0xffc00000 -> end) 115 * +----+ 116 * 117 * note that the PDE#767 VA (0xbfc00000) is defined as "PTE_BASE" 118 * note that the PDE#1023 VA (0xffc00000) is defined as "APTE_BASE" 119 * 120 * starting at VA 0xbfc00000 the current active PDP (%cr3) acts as a 121 * PTP: 122 * 123 * PTP#767 == PDP(%cr3) => maps VA 0xbfc00000 -> 0xc0000000 124 * +----+ 125 * | 0| -> maps the contents of PTP#0 at VA 0xbfc00000->0xbfc01000 126 * | | 127 * | | 128 * | 767| -> maps contents of PTP#767 (the PDP) at VA 0xbffbf000 129 * | 768| -> maps contents of first kernel PTP 130 * | | 131 * |1023| 132 * +----+ 133 * 134 * note that mapping of the PDP at PTP#959's VA (0xeffbf000) is 135 * defined as "PDP_BASE".... within that mapping there are two 136 * defines: 137 * "PDP_PDE" (0xeffbfefc) is the VA of the PDE in the PDP 138 * which points back to itself. 139 * "APDP_PDE" (0xeffbfffc) is the VA of the PDE in the PDP which 140 * establishes the recursive mapping of the alternate pmap. 141 * to set the alternate PDP, one just has to put the correct 142 * PA info in *APDP_PDE. 143 * 144 * note that in the APTE_BASE space, the APDP appears at VA 145 * "APDP_BASE" (0xfffff000). 146 */ 147 148 /* 149 * the following defines identify the slots used as described above. 150 */ 151 152 #define PDSLOT_PTE ((KERNBASE/NBPD)-1) /* 767: for recursive PDP map */ 153 #define PDSLOT_KERN (KERNBASE/NBPD) /* 768: start of kernel space */ 154 #define PDSLOT_APTE ((unsigned)1023) /* 1023: alternative recursive slot */ 155 156 /* 157 * the following defines give the virtual addresses of various MMU 158 * data structures: 159 * PTE_BASE and APTE_BASE: the base VA of the linear PTE mappings 160 * PTD_BASE and APTD_BASE: the base VA of the recursive mapping of the PTD 161 * PDP_PDE and APDP_PDE: the VA of the PDE that points back to the PDP/APDP 162 */ 163 164 #define PTE_BASE ((pt_entry_t *) (PDSLOT_PTE * NBPD) ) 165 #define APTE_BASE ((pt_entry_t *) (PDSLOT_APTE * NBPD) ) 166 #define PDP_BASE ((pd_entry_t *)(((char *)PTE_BASE) + (PDSLOT_PTE * NBPG))) 167 #define APDP_BASE ((pd_entry_t *)(((char *)APTE_BASE) + (PDSLOT_APTE * NBPG))) 168 #define PDP_PDE (PDP_BASE + PDSLOT_PTE) 169 #define APDP_PDE (PDP_BASE + PDSLOT_APTE) 170 171 /* 172 * XXXCDC: tmp xlate from old names: 173 * PTDPTDI -> PDSLOT_PTE 174 * KPTDI -> PDSLOT_KERN 175 * APTDPTDI -> PDSLOT_APTE 176 */ 177 178 /* 179 * the follow define determines how many PTPs should be set up for the 180 * kernel by locore.s at boot time. this should be large enough to 181 * get the VM system running. once the VM system is running, the 182 * pmap module can add more PTPs to the kernel area on demand. 183 */ 184 185 #ifndef NKPTP 186 #define NKPTP 4 /* 16MB to start */ 187 #endif 188 #define NKPTP_MIN 4 /* smallest value we allow */ 189 #define NKPTP_MAX (1024 - (KERNBASE/NBPD) - 1) 190 /* largest value (-1 for APTP space) */ 191 192 /* 193 * pdei/ptei: generate index into PDP/PTP from a VA 194 */ 195 #define pdei(VA) (((VA) & PD_MASK) >> PDSHIFT) 196 #define ptei(VA) (((VA) & PT_MASK) >> PGSHIFT) 197 198 /* 199 * PTP macros: 200 * a PTP's index is the PD index of the PDE that points to it 201 * a PTP's offset is the byte-offset in the PTE space that this PTP is at 202 * a PTP's VA is the first VA mapped by that PTP 203 * 204 * note that NBPG == number of bytes in a PTP (4096 bytes == 1024 entries) 205 * NBPD == number of bytes a PTP can map (4MB) 206 */ 207 208 #define ptp_i2o(I) ((I) * NBPG) /* index => offset */ 209 #define ptp_o2i(O) ((O) / NBPG) /* offset => index */ 210 #define ptp_i2v(I) ((I) * NBPD) /* index => VA */ 211 #define ptp_v2i(V) ((V) / NBPD) /* VA => index (same as pdei) */ 212 213 /* 214 * PG_AVAIL usage: we make use of the ignored bits of the PTE 215 */ 216 217 #define PG_W PG_AVAIL1 /* "wired" mapping */ 218 #define PG_PVLIST PG_AVAIL2 /* mapping has entry on pvlist */ 219 /* PG_AVAIL3 not used */ 220 221 #ifdef _KERNEL 222 /* 223 * pmap data structures: see pmap.c for details of locking. 224 */ 225 226 struct pmap; 227 typedef struct pmap *pmap_t; 228 229 /* 230 * we maintain a list of all non-kernel pmaps 231 */ 232 233 LIST_HEAD(pmap_head, pmap); /* struct pmap_head: head of a pmap list */ 234 235 /* 236 * the pmap structure 237 * 238 * note that the pm_obj contains the simple_lock, the reference count, 239 * page list, and number of PTPs within the pmap. 240 */ 241 242 struct pmap { 243 struct uvm_object pm_obj; /* object (lck by object lock) */ 244 #define pm_lock pm_obj.vmobjlock 245 LIST_ENTRY(pmap) pm_list; /* list (lck by pm_list lock) */ 246 pd_entry_t *pm_pdir; /* VA of PD (lck by object lock) */ 247 u_int32_t pm_pdirpa; /* PA of PD (read-only after create) */ 248 struct vm_page *pm_ptphint; /* pointer to a PTP in our pmap */ 249 struct pmap_statistics pm_stats; /* pmap stats (lck by object lock) */ 250 251 int pm_flags; /* see below */ 252 253 union descriptor *pm_ldt; /* user-set LDT */ 254 int pm_ldt_len; /* number of LDT entries */ 255 int pm_ldt_sel; /* LDT selector */ 256 }; 257 258 /* pm_flags */ 259 #define PMF_USER_LDT 0x01 /* pmap has user-set LDT */ 260 261 /* 262 * for each managed physical page we maintain a list of <PMAP,VA>'s 263 * which it is mapped at. the list is headed by a pv_head structure. 264 * there is one pv_head per managed phys page (allocated at boot time). 265 * the pv_head structure points to a list of pv_entry structures (each 266 * describes one mapping). 267 */ 268 269 struct pv_entry; 270 271 struct pv_head { 272 simple_lock_data_t pvh_lock; /* locks every pv on this list */ 273 struct pv_entry *pvh_list; /* head of list (locked by pvh_lock) */ 274 }; 275 276 struct pv_entry { /* locked by its list's pvh_lock */ 277 struct pv_entry *pv_next; /* next entry */ 278 struct pmap *pv_pmap; /* the pmap */ 279 vaddr_t pv_va; /* the virtual address */ 280 struct vm_page *pv_ptp; /* the vm_page of the PTP */ 281 }; 282 283 /* 284 * pv_entrys are dynamically allocated in chunks from a single page. 285 * we keep track of how many pv_entrys are in use for each page and 286 * we can free pv_entry pages if needed. there is one lock for the 287 * entire allocation system. 288 */ 289 290 struct pv_page_info { 291 TAILQ_ENTRY(pv_page) pvpi_list; 292 struct pv_entry *pvpi_pvfree; 293 int pvpi_nfree; 294 }; 295 296 /* 297 * number of pv_entry's in a pv_page 298 * (note: won't work on systems where NPBG isn't a constant) 299 */ 300 301 #define PVE_PER_PVPAGE ((NBPG - sizeof(struct pv_page_info)) / \ 302 sizeof(struct pv_entry)) 303 304 /* 305 * a pv_page: where pv_entrys are allocated from 306 */ 307 308 struct pv_page { 309 struct pv_page_info pvinfo; 310 struct pv_entry pvents[PVE_PER_PVPAGE]; 311 }; 312 313 /* 314 * pmap_remove_record: a record of VAs that have been unmapped, used to 315 * flush TLB. if we have more than PMAP_RR_MAX then we stop recording. 316 */ 317 318 #define PMAP_RR_MAX 16 /* max of 16 pages (64K) */ 319 320 struct pmap_remove_record { 321 int prr_npages; 322 vaddr_t prr_vas[PMAP_RR_MAX]; 323 }; 324 325 /* 326 * global kernel variables 327 */ 328 329 /* PTDpaddr: is the physical address of the kernel's PDP */ 330 extern u_long PTDpaddr; 331 332 extern struct pmap kernel_pmap_store; /* kernel pmap */ 333 extern int nkpde; /* current # of PDEs for kernel */ 334 extern int pmap_pg_g; /* do we support PG_G? */ 335 336 /* 337 * macros 338 */ 339 340 #define pmap_kernel() (&kernel_pmap_store) 341 #define pmap_resident_count(pmap) ((pmap)->pm_stats.resident_count) 342 #define pmap_wired_count(pmap) ((pmap)->pm_stats.wired_count) 343 #define pmap_update() /* nothing (yet) */ 344 345 #define pmap_clear_modify(pg) pmap_change_attrs(pg, 0, PG_M) 346 #define pmap_clear_reference(pg) pmap_change_attrs(pg, 0, PG_U) 347 #define pmap_copy(DP,SP,D,L,S) 348 #define pmap_is_modified(pg) pmap_test_attrs(pg, PG_M) 349 #define pmap_is_referenced(pg) pmap_test_attrs(pg, PG_U) 350 #define pmap_move(DP,SP,D,L,S) 351 #define pmap_phys_address(ppn) i386_ptob(ppn) 352 #define pmap_valid_entry(E) ((E) & PG_V) /* is PDE or PTE valid? */ 353 354 355 /* 356 * prototypes 357 */ 358 359 void pmap_activate __P((struct proc *)); 360 void pmap_bootstrap __P((vaddr_t)); 361 boolean_t pmap_change_attrs __P((struct vm_page *, int, int)); 362 void pmap_deactivate __P((struct proc *)); 363 static void pmap_page_protect __P((struct vm_page *, vm_prot_t)); 364 void pmap_page_remove __P((struct vm_page *)); 365 static void pmap_protect __P((struct pmap *, vaddr_t, 366 vaddr_t, vm_prot_t)); 367 void pmap_remove __P((struct pmap *, vaddr_t, vaddr_t)); 368 boolean_t pmap_test_attrs __P((struct vm_page *, int)); 369 static void pmap_update_pg __P((vaddr_t)); 370 static void pmap_update_2pg __P((vaddr_t,vaddr_t)); 371 void pmap_write_protect __P((struct pmap *, vaddr_t, 372 vaddr_t, vm_prot_t)); 373 374 vaddr_t reserve_dumppages __P((vaddr_t)); /* XXX: not a pmap fn */ 375 376 #define PMAP_GROWKERNEL /* turn on pmap_growkernel interface */ 377 378 /* 379 * Do idle page zero'ing uncached to avoid polluting the cache. 380 */ 381 boolean_t pmap_zero_page_uncached __P((paddr_t)); 382 #define PMAP_PAGEIDLEZERO(pa) pmap_zero_page_uncached((pa)) 383 384 /* 385 * inline functions 386 */ 387 388 /* 389 * pmap_update_pg: flush one page from the TLB (or flush the whole thing 390 * if hardware doesn't support one-page flushing) 391 */ 392 393 __inline static void 394 pmap_update_pg(va) 395 vaddr_t va; 396 { 397 #if defined(I386_CPU) 398 if (cpu_class == CPUCLASS_386) 399 tlbflush(); 400 else 401 #endif 402 invlpg((u_int) va); 403 } 404 405 /* 406 * pmap_update_2pg: flush two pages from the TLB 407 */ 408 409 __inline static void 410 pmap_update_2pg(va, vb) 411 vaddr_t va, vb; 412 { 413 #if defined(I386_CPU) 414 if (cpu_class == CPUCLASS_386) 415 tlbflush(); 416 else 417 #endif 418 { 419 invlpg((u_int) va); 420 invlpg((u_int) vb); 421 } 422 } 423 424 /* 425 * pmap_page_protect: change the protection of all recorded mappings 426 * of a managed page 427 * 428 * => this function is a frontend for pmap_page_remove/pmap_change_attrs 429 * => we only have to worry about making the page more protected. 430 * unprotecting a page is done on-demand at fault time. 431 */ 432 433 __inline static void 434 pmap_page_protect(pg, prot) 435 struct vm_page *pg; 436 vm_prot_t prot; 437 { 438 if ((prot & VM_PROT_WRITE) == 0) { 439 if (prot & (VM_PROT_READ|VM_PROT_EXECUTE)) { 440 (void) pmap_change_attrs(pg, PG_RO, PG_RW); 441 } else { 442 pmap_page_remove(pg); 443 } 444 } 445 } 446 447 /* 448 * pmap_protect: change the protection of pages in a pmap 449 * 450 * => this function is a frontend for pmap_remove/pmap_write_protect 451 * => we only have to worry about making the page more protected. 452 * unprotecting a page is done on-demand at fault time. 453 */ 454 455 __inline static void 456 pmap_protect(pmap, sva, eva, prot) 457 struct pmap *pmap; 458 vaddr_t sva, eva; 459 vm_prot_t prot; 460 { 461 if ((prot & VM_PROT_WRITE) == 0) { 462 if (prot & (VM_PROT_READ|VM_PROT_EXECUTE)) { 463 pmap_write_protect(pmap, sva, eva, prot); 464 } else { 465 pmap_remove(pmap, sva, eva); 466 } 467 } 468 } 469 470 /* 471 * various address inlines 472 * 473 * vtopte: return a pointer to the PTE mapping a VA, works only for 474 * user and PT addresses 475 * 476 * kvtopte: return a pointer to the PTE mapping a kernel VA 477 */ 478 479 #include <lib/libkern/libkern.h> 480 481 static __inline pt_entry_t * 482 vtopte(vaddr_t va) 483 { 484 485 KASSERT(va < (PDSLOT_KERN << PDSHIFT)); 486 487 return (PTE_BASE + i386_btop(va)); 488 } 489 490 static __inline pt_entry_t * 491 kvtopte(vaddr_t va) 492 { 493 494 KASSERT(va >= (PDSLOT_KERN << PDSHIFT)); 495 496 #ifdef LARGEPAGES 497 { 498 pd_entry_t *pde; 499 500 pde = PDP_BASE + pdei(va); 501 if (*pde & PG_PS) 502 return ((pt_entry_t *)pde); 503 } 504 #endif 505 506 return (PTE_BASE + i386_btop(va)); 507 } 508 509 paddr_t vtophys __P((vaddr_t)); 510 vaddr_t pmap_map __P((vaddr_t, paddr_t, paddr_t, vm_prot_t)); 511 512 #if defined(USER_LDT) 513 void pmap_ldt_cleanup __P((struct proc *)); 514 #define PMAP_FORK 515 #endif /* USER_LDT */ 516 517 #endif /* _KERNEL */ 518 #endif /* _I386_PMAP_H_ */ 519