1 /* 2 * Copyright IBM Corp. 2007,2011 3 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com> 4 */ 5 6 #include <linux/sched.h> 7 #include <linux/kernel.h> 8 #include <linux/errno.h> 9 #include <linux/gfp.h> 10 #include <linux/mm.h> 11 #include <linux/swap.h> 12 #include <linux/smp.h> 13 #include <linux/highmem.h> 14 #include <linux/pagemap.h> 15 #include <linux/spinlock.h> 16 #include <linux/module.h> 17 #include <linux/quicklist.h> 18 #include <linux/rcupdate.h> 19 #include <linux/slab.h> 20 21 #include <asm/system.h> 22 #include <asm/pgtable.h> 23 #include <asm/pgalloc.h> 24 #include <asm/tlb.h> 25 #include <asm/tlbflush.h> 26 #include <asm/mmu_context.h> 27 28 #ifndef CONFIG_64BIT 29 #define ALLOC_ORDER 1 30 #define FRAG_MASK 0x0f 31 #else 32 #define ALLOC_ORDER 2 33 #define FRAG_MASK 0x03 34 #endif 35 36 unsigned long VMALLOC_START = VMALLOC_END - VMALLOC_SIZE; 37 EXPORT_SYMBOL(VMALLOC_START); 38 39 static int __init parse_vmalloc(char *arg) 40 { 41 if (!arg) 42 return -EINVAL; 43 VMALLOC_START = (VMALLOC_END - memparse(arg, &arg)) & PAGE_MASK; 44 return 0; 45 } 46 early_param("vmalloc", parse_vmalloc); 47 48 unsigned long *crst_table_alloc(struct mm_struct *mm) 49 { 50 struct page *page = alloc_pages(GFP_KERNEL, ALLOC_ORDER); 51 52 if (!page) 53 return NULL; 54 return (unsigned long *) page_to_phys(page); 55 } 56 57 void crst_table_free(struct mm_struct *mm, unsigned long *table) 58 { 59 free_pages((unsigned long) table, ALLOC_ORDER); 60 } 61 62 #ifdef CONFIG_64BIT 63 int crst_table_upgrade(struct mm_struct *mm, unsigned long limit) 64 { 65 unsigned long *table, *pgd; 66 unsigned long entry; 67 68 BUG_ON(limit > (1UL << 53)); 69 repeat: 70 table = crst_table_alloc(mm); 71 if (!table) 72 return -ENOMEM; 73 spin_lock_bh(&mm->page_table_lock); 74 if (mm->context.asce_limit < limit) { 75 pgd = (unsigned long *) mm->pgd; 76 if (mm->context.asce_limit <= (1UL << 31)) { 77 entry = _REGION3_ENTRY_EMPTY; 78 mm->context.asce_limit = 1UL << 42; 79 mm->context.asce_bits = _ASCE_TABLE_LENGTH | 80 _ASCE_USER_BITS | 81 _ASCE_TYPE_REGION3; 82 } else { 83 entry = _REGION2_ENTRY_EMPTY; 84 mm->context.asce_limit = 1UL << 53; 85 mm->context.asce_bits = _ASCE_TABLE_LENGTH | 86 _ASCE_USER_BITS | 87 _ASCE_TYPE_REGION2; 88 } 89 crst_table_init(table, entry); 90 pgd_populate(mm, (pgd_t *) table, (pud_t *) pgd); 91 mm->pgd = (pgd_t *) table; 92 mm->task_size = mm->context.asce_limit; 93 table = NULL; 94 } 95 spin_unlock_bh(&mm->page_table_lock); 96 if (table) 97 crst_table_free(mm, table); 98 if (mm->context.asce_limit < limit) 99 goto repeat; 100 update_mm(mm, current); 101 return 0; 102 } 103 104 void crst_table_downgrade(struct mm_struct *mm, unsigned long limit) 105 { 106 pgd_t *pgd; 107 108 if (mm->context.asce_limit <= limit) 109 return; 110 __tlb_flush_mm(mm); 111 while (mm->context.asce_limit > limit) { 112 pgd = mm->pgd; 113 switch (pgd_val(*pgd) & _REGION_ENTRY_TYPE_MASK) { 114 case _REGION_ENTRY_TYPE_R2: 115 mm->context.asce_limit = 1UL << 42; 116 mm->context.asce_bits = _ASCE_TABLE_LENGTH | 117 _ASCE_USER_BITS | 118 _ASCE_TYPE_REGION3; 119 break; 120 case _REGION_ENTRY_TYPE_R3: 121 mm->context.asce_limit = 1UL << 31; 122 mm->context.asce_bits = _ASCE_TABLE_LENGTH | 123 _ASCE_USER_BITS | 124 _ASCE_TYPE_SEGMENT; 125 break; 126 default: 127 BUG(); 128 } 129 mm->pgd = (pgd_t *) (pgd_val(*pgd) & _REGION_ENTRY_ORIGIN); 130 mm->task_size = mm->context.asce_limit; 131 crst_table_free(mm, (unsigned long *) pgd); 132 } 133 update_mm(mm, current); 134 } 135 #endif 136 137 #ifdef CONFIG_PGSTE 138 139 /** 140 * gmap_alloc - allocate a guest address space 141 * @mm: pointer to the parent mm_struct 142 * 143 * Returns a guest address space structure. 144 */ 145 struct gmap *gmap_alloc(struct mm_struct *mm) 146 { 147 struct gmap *gmap; 148 struct page *page; 149 unsigned long *table; 150 151 gmap = kzalloc(sizeof(struct gmap), GFP_KERNEL); 152 if (!gmap) 153 goto out; 154 INIT_LIST_HEAD(&gmap->crst_list); 155 gmap->mm = mm; 156 page = alloc_pages(GFP_KERNEL, ALLOC_ORDER); 157 if (!page) 158 goto out_free; 159 list_add(&page->lru, &gmap->crst_list); 160 table = (unsigned long *) page_to_phys(page); 161 crst_table_init(table, _REGION1_ENTRY_EMPTY); 162 gmap->table = table; 163 gmap->asce = _ASCE_TYPE_REGION1 | _ASCE_TABLE_LENGTH | 164 _ASCE_USER_BITS | __pa(table); 165 list_add(&gmap->list, &mm->context.gmap_list); 166 return gmap; 167 168 out_free: 169 kfree(gmap); 170 out: 171 return NULL; 172 } 173 EXPORT_SYMBOL_GPL(gmap_alloc); 174 175 static int gmap_unlink_segment(struct gmap *gmap, unsigned long *table) 176 { 177 struct gmap_pgtable *mp; 178 struct gmap_rmap *rmap; 179 struct page *page; 180 181 if (*table & _SEGMENT_ENTRY_INV) 182 return 0; 183 page = pfn_to_page(*table >> PAGE_SHIFT); 184 mp = (struct gmap_pgtable *) page->index; 185 list_for_each_entry(rmap, &mp->mapper, list) { 186 if (rmap->entry != table) 187 continue; 188 list_del(&rmap->list); 189 kfree(rmap); 190 break; 191 } 192 *table = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | mp->vmaddr; 193 return 1; 194 } 195 196 static void gmap_flush_tlb(struct gmap *gmap) 197 { 198 if (MACHINE_HAS_IDTE) 199 __tlb_flush_idte((unsigned long) gmap->table | 200 _ASCE_TYPE_REGION1); 201 else 202 __tlb_flush_global(); 203 } 204 205 /** 206 * gmap_free - free a guest address space 207 * @gmap: pointer to the guest address space structure 208 */ 209 void gmap_free(struct gmap *gmap) 210 { 211 struct page *page, *next; 212 unsigned long *table; 213 int i; 214 215 216 /* Flush tlb. */ 217 if (MACHINE_HAS_IDTE) 218 __tlb_flush_idte((unsigned long) gmap->table | 219 _ASCE_TYPE_REGION1); 220 else 221 __tlb_flush_global(); 222 223 /* Free all segment & region tables. */ 224 down_read(&gmap->mm->mmap_sem); 225 spin_lock(&gmap->mm->page_table_lock); 226 list_for_each_entry_safe(page, next, &gmap->crst_list, lru) { 227 table = (unsigned long *) page_to_phys(page); 228 if ((*table & _REGION_ENTRY_TYPE_MASK) == 0) 229 /* Remove gmap rmap structures for segment table. */ 230 for (i = 0; i < PTRS_PER_PMD; i++, table++) 231 gmap_unlink_segment(gmap, table); 232 __free_pages(page, ALLOC_ORDER); 233 } 234 spin_unlock(&gmap->mm->page_table_lock); 235 up_read(&gmap->mm->mmap_sem); 236 list_del(&gmap->list); 237 kfree(gmap); 238 } 239 EXPORT_SYMBOL_GPL(gmap_free); 240 241 /** 242 * gmap_enable - switch primary space to the guest address space 243 * @gmap: pointer to the guest address space structure 244 */ 245 void gmap_enable(struct gmap *gmap) 246 { 247 S390_lowcore.gmap = (unsigned long) gmap; 248 } 249 EXPORT_SYMBOL_GPL(gmap_enable); 250 251 /** 252 * gmap_disable - switch back to the standard primary address space 253 * @gmap: pointer to the guest address space structure 254 */ 255 void gmap_disable(struct gmap *gmap) 256 { 257 S390_lowcore.gmap = 0UL; 258 } 259 EXPORT_SYMBOL_GPL(gmap_disable); 260 261 /* 262 * gmap_alloc_table is assumed to be called with mmap_sem held 263 */ 264 static int gmap_alloc_table(struct gmap *gmap, 265 unsigned long *table, unsigned long init) 266 { 267 struct page *page; 268 unsigned long *new; 269 270 page = alloc_pages(GFP_KERNEL, ALLOC_ORDER); 271 if (!page) 272 return -ENOMEM; 273 new = (unsigned long *) page_to_phys(page); 274 crst_table_init(new, init); 275 if (*table & _REGION_ENTRY_INV) { 276 list_add(&page->lru, &gmap->crst_list); 277 *table = (unsigned long) new | _REGION_ENTRY_LENGTH | 278 (*table & _REGION_ENTRY_TYPE_MASK); 279 } else 280 __free_pages(page, ALLOC_ORDER); 281 return 0; 282 } 283 284 /** 285 * gmap_unmap_segment - unmap segment from the guest address space 286 * @gmap: pointer to the guest address space structure 287 * @addr: address in the guest address space 288 * @len: length of the memory area to unmap 289 * 290 * Returns 0 if the unmap succeded, -EINVAL if not. 291 */ 292 int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len) 293 { 294 unsigned long *table; 295 unsigned long off; 296 int flush; 297 298 if ((to | len) & (PMD_SIZE - 1)) 299 return -EINVAL; 300 if (len == 0 || to + len < to) 301 return -EINVAL; 302 303 flush = 0; 304 down_read(&gmap->mm->mmap_sem); 305 spin_lock(&gmap->mm->page_table_lock); 306 for (off = 0; off < len; off += PMD_SIZE) { 307 /* Walk the guest addr space page table */ 308 table = gmap->table + (((to + off) >> 53) & 0x7ff); 309 if (*table & _REGION_ENTRY_INV) 310 goto out; 311 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); 312 table = table + (((to + off) >> 42) & 0x7ff); 313 if (*table & _REGION_ENTRY_INV) 314 goto out; 315 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); 316 table = table + (((to + off) >> 31) & 0x7ff); 317 if (*table & _REGION_ENTRY_INV) 318 goto out; 319 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); 320 table = table + (((to + off) >> 20) & 0x7ff); 321 322 /* Clear segment table entry in guest address space. */ 323 flush |= gmap_unlink_segment(gmap, table); 324 *table = _SEGMENT_ENTRY_INV; 325 } 326 out: 327 spin_unlock(&gmap->mm->page_table_lock); 328 up_read(&gmap->mm->mmap_sem); 329 if (flush) 330 gmap_flush_tlb(gmap); 331 return 0; 332 } 333 EXPORT_SYMBOL_GPL(gmap_unmap_segment); 334 335 /** 336 * gmap_mmap_segment - map a segment to the guest address space 337 * @gmap: pointer to the guest address space structure 338 * @from: source address in the parent address space 339 * @to: target address in the guest address space 340 * 341 * Returns 0 if the mmap succeded, -EINVAL or -ENOMEM if not. 342 */ 343 int gmap_map_segment(struct gmap *gmap, unsigned long from, 344 unsigned long to, unsigned long len) 345 { 346 unsigned long *table; 347 unsigned long off; 348 int flush; 349 350 if ((from | to | len) & (PMD_SIZE - 1)) 351 return -EINVAL; 352 if (len == 0 || from + len > PGDIR_SIZE || 353 from + len < from || to + len < to) 354 return -EINVAL; 355 356 flush = 0; 357 down_read(&gmap->mm->mmap_sem); 358 spin_lock(&gmap->mm->page_table_lock); 359 for (off = 0; off < len; off += PMD_SIZE) { 360 /* Walk the gmap address space page table */ 361 table = gmap->table + (((to + off) >> 53) & 0x7ff); 362 if ((*table & _REGION_ENTRY_INV) && 363 gmap_alloc_table(gmap, table, _REGION2_ENTRY_EMPTY)) 364 goto out_unmap; 365 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); 366 table = table + (((to + off) >> 42) & 0x7ff); 367 if ((*table & _REGION_ENTRY_INV) && 368 gmap_alloc_table(gmap, table, _REGION3_ENTRY_EMPTY)) 369 goto out_unmap; 370 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); 371 table = table + (((to + off) >> 31) & 0x7ff); 372 if ((*table & _REGION_ENTRY_INV) && 373 gmap_alloc_table(gmap, table, _SEGMENT_ENTRY_EMPTY)) 374 goto out_unmap; 375 table = (unsigned long *) (*table & _REGION_ENTRY_ORIGIN); 376 table = table + (((to + off) >> 20) & 0x7ff); 377 378 /* Store 'from' address in an invalid segment table entry. */ 379 flush |= gmap_unlink_segment(gmap, table); 380 *table = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | (from + off); 381 } 382 spin_unlock(&gmap->mm->page_table_lock); 383 up_read(&gmap->mm->mmap_sem); 384 if (flush) 385 gmap_flush_tlb(gmap); 386 return 0; 387 388 out_unmap: 389 spin_unlock(&gmap->mm->page_table_lock); 390 up_read(&gmap->mm->mmap_sem); 391 gmap_unmap_segment(gmap, to, len); 392 return -ENOMEM; 393 } 394 EXPORT_SYMBOL_GPL(gmap_map_segment); 395 396 /* 397 * this function is assumed to be called with mmap_sem held 398 */ 399 unsigned long __gmap_fault(unsigned long address, struct gmap *gmap) 400 { 401 unsigned long *table, vmaddr, segment; 402 struct mm_struct *mm; 403 struct gmap_pgtable *mp; 404 struct gmap_rmap *rmap; 405 struct vm_area_struct *vma; 406 struct page *page; 407 pgd_t *pgd; 408 pud_t *pud; 409 pmd_t *pmd; 410 411 current->thread.gmap_addr = address; 412 mm = gmap->mm; 413 /* Walk the gmap address space page table */ 414 table = gmap->table + ((address >> 53) & 0x7ff); 415 if (unlikely(*table & _REGION_ENTRY_INV)) 416 return -EFAULT; 417 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); 418 table = table + ((address >> 42) & 0x7ff); 419 if (unlikely(*table & _REGION_ENTRY_INV)) 420 return -EFAULT; 421 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); 422 table = table + ((address >> 31) & 0x7ff); 423 if (unlikely(*table & _REGION_ENTRY_INV)) 424 return -EFAULT; 425 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); 426 table = table + ((address >> 20) & 0x7ff); 427 428 /* Convert the gmap address to an mm address. */ 429 segment = *table; 430 if (likely(!(segment & _SEGMENT_ENTRY_INV))) { 431 page = pfn_to_page(segment >> PAGE_SHIFT); 432 mp = (struct gmap_pgtable *) page->index; 433 return mp->vmaddr | (address & ~PMD_MASK); 434 } else if (segment & _SEGMENT_ENTRY_RO) { 435 vmaddr = segment & _SEGMENT_ENTRY_ORIGIN; 436 vma = find_vma(mm, vmaddr); 437 if (!vma || vma->vm_start > vmaddr) 438 return -EFAULT; 439 440 /* Walk the parent mm page table */ 441 pgd = pgd_offset(mm, vmaddr); 442 pud = pud_alloc(mm, pgd, vmaddr); 443 if (!pud) 444 return -ENOMEM; 445 pmd = pmd_alloc(mm, pud, vmaddr); 446 if (!pmd) 447 return -ENOMEM; 448 if (!pmd_present(*pmd) && 449 __pte_alloc(mm, vma, pmd, vmaddr)) 450 return -ENOMEM; 451 /* pmd now points to a valid segment table entry. */ 452 rmap = kmalloc(sizeof(*rmap), GFP_KERNEL|__GFP_REPEAT); 453 if (!rmap) 454 return -ENOMEM; 455 /* Link gmap segment table entry location to page table. */ 456 page = pmd_page(*pmd); 457 mp = (struct gmap_pgtable *) page->index; 458 rmap->entry = table; 459 spin_lock(&mm->page_table_lock); 460 list_add(&rmap->list, &mp->mapper); 461 spin_unlock(&mm->page_table_lock); 462 /* Set gmap segment table entry to page table. */ 463 *table = pmd_val(*pmd) & PAGE_MASK; 464 return vmaddr | (address & ~PMD_MASK); 465 } 466 return -EFAULT; 467 } 468 469 unsigned long gmap_fault(unsigned long address, struct gmap *gmap) 470 { 471 unsigned long rc; 472 473 down_read(&gmap->mm->mmap_sem); 474 rc = __gmap_fault(address, gmap); 475 up_read(&gmap->mm->mmap_sem); 476 477 return rc; 478 } 479 EXPORT_SYMBOL_GPL(gmap_fault); 480 481 void gmap_discard(unsigned long from, unsigned long to, struct gmap *gmap) 482 { 483 484 unsigned long *table, address, size; 485 struct vm_area_struct *vma; 486 struct gmap_pgtable *mp; 487 struct page *page; 488 489 down_read(&gmap->mm->mmap_sem); 490 address = from; 491 while (address < to) { 492 /* Walk the gmap address space page table */ 493 table = gmap->table + ((address >> 53) & 0x7ff); 494 if (unlikely(*table & _REGION_ENTRY_INV)) { 495 address = (address + PMD_SIZE) & PMD_MASK; 496 continue; 497 } 498 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); 499 table = table + ((address >> 42) & 0x7ff); 500 if (unlikely(*table & _REGION_ENTRY_INV)) { 501 address = (address + PMD_SIZE) & PMD_MASK; 502 continue; 503 } 504 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); 505 table = table + ((address >> 31) & 0x7ff); 506 if (unlikely(*table & _REGION_ENTRY_INV)) { 507 address = (address + PMD_SIZE) & PMD_MASK; 508 continue; 509 } 510 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); 511 table = table + ((address >> 20) & 0x7ff); 512 if (unlikely(*table & _SEGMENT_ENTRY_INV)) { 513 address = (address + PMD_SIZE) & PMD_MASK; 514 continue; 515 } 516 page = pfn_to_page(*table >> PAGE_SHIFT); 517 mp = (struct gmap_pgtable *) page->index; 518 vma = find_vma(gmap->mm, mp->vmaddr); 519 size = min(to - address, PMD_SIZE - (address & ~PMD_MASK)); 520 zap_page_range(vma, mp->vmaddr | (address & ~PMD_MASK), 521 size, NULL); 522 address = (address + PMD_SIZE) & PMD_MASK; 523 } 524 up_read(&gmap->mm->mmap_sem); 525 } 526 EXPORT_SYMBOL_GPL(gmap_discard); 527 528 void gmap_unmap_notifier(struct mm_struct *mm, unsigned long *table) 529 { 530 struct gmap_rmap *rmap, *next; 531 struct gmap_pgtable *mp; 532 struct page *page; 533 int flush; 534 535 flush = 0; 536 spin_lock(&mm->page_table_lock); 537 page = pfn_to_page(__pa(table) >> PAGE_SHIFT); 538 mp = (struct gmap_pgtable *) page->index; 539 list_for_each_entry_safe(rmap, next, &mp->mapper, list) { 540 *rmap->entry = 541 _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | mp->vmaddr; 542 list_del(&rmap->list); 543 kfree(rmap); 544 flush = 1; 545 } 546 spin_unlock(&mm->page_table_lock); 547 if (flush) 548 __tlb_flush_global(); 549 } 550 551 static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm, 552 unsigned long vmaddr) 553 { 554 struct page *page; 555 unsigned long *table; 556 struct gmap_pgtable *mp; 557 558 page = alloc_page(GFP_KERNEL|__GFP_REPEAT); 559 if (!page) 560 return NULL; 561 mp = kmalloc(sizeof(*mp), GFP_KERNEL|__GFP_REPEAT); 562 if (!mp) { 563 __free_page(page); 564 return NULL; 565 } 566 pgtable_page_ctor(page); 567 mp->vmaddr = vmaddr & PMD_MASK; 568 INIT_LIST_HEAD(&mp->mapper); 569 page->index = (unsigned long) mp; 570 atomic_set(&page->_mapcount, 3); 571 table = (unsigned long *) page_to_phys(page); 572 clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE/2); 573 clear_table(table + PTRS_PER_PTE, 0, PAGE_SIZE/2); 574 return table; 575 } 576 577 static inline void page_table_free_pgste(unsigned long *table) 578 { 579 struct page *page; 580 struct gmap_pgtable *mp; 581 582 page = pfn_to_page(__pa(table) >> PAGE_SHIFT); 583 mp = (struct gmap_pgtable *) page->index; 584 BUG_ON(!list_empty(&mp->mapper)); 585 pgtable_page_ctor(page); 586 atomic_set(&page->_mapcount, -1); 587 kfree(mp); 588 __free_page(page); 589 } 590 591 #else /* CONFIG_PGSTE */ 592 593 static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm, 594 unsigned long vmaddr) 595 { 596 return NULL; 597 } 598 599 static inline void page_table_free_pgste(unsigned long *table) 600 { 601 } 602 603 static inline void gmap_unmap_notifier(struct mm_struct *mm, 604 unsigned long *table) 605 { 606 } 607 608 #endif /* CONFIG_PGSTE */ 609 610 static inline unsigned int atomic_xor_bits(atomic_t *v, unsigned int bits) 611 { 612 unsigned int old, new; 613 614 do { 615 old = atomic_read(v); 616 new = old ^ bits; 617 } while (atomic_cmpxchg(v, old, new) != old); 618 return new; 619 } 620 621 /* 622 * page table entry allocation/free routines. 623 */ 624 unsigned long *page_table_alloc(struct mm_struct *mm, unsigned long vmaddr) 625 { 626 struct page *page; 627 unsigned long *table; 628 unsigned int mask, bit; 629 630 if (mm_has_pgste(mm)) 631 return page_table_alloc_pgste(mm, vmaddr); 632 /* Allocate fragments of a 4K page as 1K/2K page table */ 633 spin_lock_bh(&mm->context.list_lock); 634 mask = FRAG_MASK; 635 if (!list_empty(&mm->context.pgtable_list)) { 636 page = list_first_entry(&mm->context.pgtable_list, 637 struct page, lru); 638 table = (unsigned long *) page_to_phys(page); 639 mask = atomic_read(&page->_mapcount); 640 mask = mask | (mask >> 4); 641 } 642 if ((mask & FRAG_MASK) == FRAG_MASK) { 643 spin_unlock_bh(&mm->context.list_lock); 644 page = alloc_page(GFP_KERNEL|__GFP_REPEAT); 645 if (!page) 646 return NULL; 647 pgtable_page_ctor(page); 648 atomic_set(&page->_mapcount, 1); 649 table = (unsigned long *) page_to_phys(page); 650 clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE); 651 spin_lock_bh(&mm->context.list_lock); 652 list_add(&page->lru, &mm->context.pgtable_list); 653 } else { 654 for (bit = 1; mask & bit; bit <<= 1) 655 table += PTRS_PER_PTE; 656 mask = atomic_xor_bits(&page->_mapcount, bit); 657 if ((mask & FRAG_MASK) == FRAG_MASK) 658 list_del(&page->lru); 659 } 660 spin_unlock_bh(&mm->context.list_lock); 661 return table; 662 } 663 664 void page_table_free(struct mm_struct *mm, unsigned long *table) 665 { 666 struct page *page; 667 unsigned int bit, mask; 668 669 if (mm_has_pgste(mm)) { 670 gmap_unmap_notifier(mm, table); 671 return page_table_free_pgste(table); 672 } 673 /* Free 1K/2K page table fragment of a 4K page */ 674 page = pfn_to_page(__pa(table) >> PAGE_SHIFT); 675 bit = 1 << ((__pa(table) & ~PAGE_MASK)/(PTRS_PER_PTE*sizeof(pte_t))); 676 spin_lock_bh(&mm->context.list_lock); 677 if ((atomic_read(&page->_mapcount) & FRAG_MASK) != FRAG_MASK) 678 list_del(&page->lru); 679 mask = atomic_xor_bits(&page->_mapcount, bit); 680 if (mask & FRAG_MASK) 681 list_add(&page->lru, &mm->context.pgtable_list); 682 spin_unlock_bh(&mm->context.list_lock); 683 if (mask == 0) { 684 pgtable_page_dtor(page); 685 atomic_set(&page->_mapcount, -1); 686 __free_page(page); 687 } 688 } 689 690 #ifdef CONFIG_HAVE_RCU_TABLE_FREE 691 692 static void __page_table_free_rcu(void *table, unsigned bit) 693 { 694 struct page *page; 695 696 if (bit == FRAG_MASK) 697 return page_table_free_pgste(table); 698 /* Free 1K/2K page table fragment of a 4K page */ 699 page = pfn_to_page(__pa(table) >> PAGE_SHIFT); 700 if (atomic_xor_bits(&page->_mapcount, bit) == 0) { 701 pgtable_page_dtor(page); 702 atomic_set(&page->_mapcount, -1); 703 __free_page(page); 704 } 705 } 706 707 void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table) 708 { 709 struct mm_struct *mm; 710 struct page *page; 711 unsigned int bit, mask; 712 713 mm = tlb->mm; 714 if (mm_has_pgste(mm)) { 715 gmap_unmap_notifier(mm, table); 716 table = (unsigned long *) (__pa(table) | FRAG_MASK); 717 tlb_remove_table(tlb, table); 718 return; 719 } 720 bit = 1 << ((__pa(table) & ~PAGE_MASK) / (PTRS_PER_PTE*sizeof(pte_t))); 721 page = pfn_to_page(__pa(table) >> PAGE_SHIFT); 722 spin_lock_bh(&mm->context.list_lock); 723 if ((atomic_read(&page->_mapcount) & FRAG_MASK) != FRAG_MASK) 724 list_del(&page->lru); 725 mask = atomic_xor_bits(&page->_mapcount, bit | (bit << 4)); 726 if (mask & FRAG_MASK) 727 list_add_tail(&page->lru, &mm->context.pgtable_list); 728 spin_unlock_bh(&mm->context.list_lock); 729 table = (unsigned long *) (__pa(table) | (bit << 4)); 730 tlb_remove_table(tlb, table); 731 } 732 733 void __tlb_remove_table(void *_table) 734 { 735 const unsigned long mask = (FRAG_MASK << 4) | FRAG_MASK; 736 void *table = (void *)((unsigned long) _table & ~mask); 737 unsigned type = (unsigned long) _table & mask; 738 739 if (type) 740 __page_table_free_rcu(table, type); 741 else 742 free_pages((unsigned long) table, ALLOC_ORDER); 743 } 744 745 #endif 746 747 /* 748 * switch on pgstes for its userspace process (for kvm) 749 */ 750 int s390_enable_sie(void) 751 { 752 struct task_struct *tsk = current; 753 struct mm_struct *mm, *old_mm; 754 755 /* Do we have switched amode? If no, we cannot do sie */ 756 if (user_mode == HOME_SPACE_MODE) 757 return -EINVAL; 758 759 /* Do we have pgstes? if yes, we are done */ 760 if (mm_has_pgste(tsk->mm)) 761 return 0; 762 763 /* lets check if we are allowed to replace the mm */ 764 task_lock(tsk); 765 if (!tsk->mm || atomic_read(&tsk->mm->mm_users) > 1 || 766 #ifdef CONFIG_AIO 767 !hlist_empty(&tsk->mm->ioctx_list) || 768 #endif 769 tsk->mm != tsk->active_mm) { 770 task_unlock(tsk); 771 return -EINVAL; 772 } 773 task_unlock(tsk); 774 775 /* we copy the mm and let dup_mm create the page tables with_pgstes */ 776 tsk->mm->context.alloc_pgste = 1; 777 mm = dup_mm(tsk); 778 tsk->mm->context.alloc_pgste = 0; 779 if (!mm) 780 return -ENOMEM; 781 782 /* Now lets check again if something happened */ 783 task_lock(tsk); 784 if (!tsk->mm || atomic_read(&tsk->mm->mm_users) > 1 || 785 #ifdef CONFIG_AIO 786 !hlist_empty(&tsk->mm->ioctx_list) || 787 #endif 788 tsk->mm != tsk->active_mm) { 789 mmput(mm); 790 task_unlock(tsk); 791 return -EINVAL; 792 } 793 794 /* ok, we are alone. No ptrace, no threads, etc. */ 795 old_mm = tsk->mm; 796 tsk->mm = tsk->active_mm = mm; 797 preempt_disable(); 798 update_mm(mm, tsk); 799 atomic_inc(&mm->context.attach_count); 800 atomic_dec(&old_mm->context.attach_count); 801 cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm)); 802 preempt_enable(); 803 task_unlock(tsk); 804 mmput(old_mm); 805 return 0; 806 } 807 EXPORT_SYMBOL_GPL(s390_enable_sie); 808 809 #if defined(CONFIG_DEBUG_PAGEALLOC) && defined(CONFIG_HIBERNATION) 810 bool kernel_page_present(struct page *page) 811 { 812 unsigned long addr; 813 int cc; 814 815 addr = page_to_phys(page); 816 asm volatile( 817 " lra %1,0(%1)\n" 818 " ipm %0\n" 819 " srl %0,28" 820 : "=d" (cc), "+a" (addr) : : "cc"); 821 return cc == 0; 822 } 823 #endif /* CONFIG_HIBERNATION && CONFIG_DEBUG_PAGEALLOC */ 824