arch/s390/mm/pgtable.c

   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/spinlock.h>
  14 #include <linux/rcupdate.h>
  15 #include <linux/slab.h>
  16 #include <linux/swapops.h>
  17 #include <linux/sysctl.h>
  18 #include <linux/ksm.h>
  19 #include <linux/mman.h>
  20
  21 #include <asm/pgtable.h>
  22 #include <asm/pgalloc.h>
  23 #include <asm/tlb.h>
  24 #include <asm/tlbflush.h>
  25 #include <asm/mmu_context.h>
  26
  27 static inline pte_t ptep_flush_direct(struct mm_struct *mm,
  28                                       unsigned long addr, pte_t *ptep)
  29 {
  30         pte_t old;
  31
  32         old = *ptep;
  33         if (unlikely(pte_val(old) & _PAGE_INVALID))
  34                 return old;
  35         atomic_inc(&mm->context.flush_count);
  36         if (MACHINE_HAS_TLB_LC &&
  37             cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
  38                 __ptep_ipte(addr, ptep, IPTE_LOCAL);
  39         else
  40                 __ptep_ipte(addr, ptep, IPTE_GLOBAL);
  41         atomic_dec(&mm->context.flush_count);
  42         return old;
  43 }
  44
  45 static inline pte_t ptep_flush_lazy(struct mm_struct *mm,
  46                                     unsigned long addr, pte_t *ptep)
  47 {
  48         pte_t old;
  49
  50         old = *ptep;
  51         if (unlikely(pte_val(old) & _PAGE_INVALID))
  52                 return old;
  53         atomic_inc(&mm->context.flush_count);
  54         if (cpumask_equal(&mm->context.cpu_attach_mask,
  55                           cpumask_of(smp_processor_id()))) {
  56                 pte_val(*ptep) |= _PAGE_INVALID;
  57                 mm->context.flush_mm = 1;
  58         } else
  59                 __ptep_ipte(addr, ptep, IPTE_GLOBAL);
  60         atomic_dec(&mm->context.flush_count);
  61         return old;
  62 }
  63
  64 static inline pgste_t pgste_get_lock(pte_t *ptep)
  65 {
  66         unsigned long new = 0;
  67 #ifdef CONFIG_PGSTE
  68         unsigned long old;
  69
  70         asm(
  71                 "       lg      %0,%2\n"
  72                 "0:     lgr     %1,%0\n"
  73                 "       nihh    %0,0xff7f\n"    /* clear PCL bit in old */
  74                 "       oihh    %1,0x0080\n"    /* set PCL bit in new */
  75                 "       csg     %0,%1,%2\n"
  76                 "       jl      0b\n"
  77                 : "=&d" (old), "=&d" (new), "=Q" (ptep[PTRS_PER_PTE])
  78                 : "Q" (ptep[PTRS_PER_PTE]) : "cc", "memory");
  79 #endif
  80         return __pgste(new);
  81 }
  82
  83 static inline void pgste_set_unlock(pte_t *ptep, pgste_t pgste)
  84 {
  85 #ifdef CONFIG_PGSTE
  86         asm(
  87                 "       nihh    %1,0xff7f\n"    /* clear PCL bit */
  88                 "       stg     %1,%0\n"
  89                 : "=Q" (ptep[PTRS_PER_PTE])
  90                 : "d" (pgste_val(pgste)), "Q" (ptep[PTRS_PER_PTE])
  91                 : "cc", "memory");
  92 #endif
  93 }
  94
  95 static inline pgste_t pgste_get(pte_t *ptep)
  96 {
  97         unsigned long pgste = 0;
  98 #ifdef CONFIG_PGSTE
  99         pgste = *(unsigned long *)(ptep + PTRS_PER_PTE);
 100 #endif
 101         return __pgste(pgste);
 102 }
 103
 104 static inline void pgste_set(pte_t *ptep, pgste_t pgste)
 105 {
 106 #ifdef CONFIG_PGSTE
 107         *(pgste_t *)(ptep + PTRS_PER_PTE) = pgste;
 108 #endif
 109 }
 110
 111 static inline pgste_t pgste_update_all(pte_t pte, pgste_t pgste,
 112                                        struct mm_struct *mm)
 113 {
 114 #ifdef CONFIG_PGSTE
 115         unsigned long address, bits, skey;
 116
 117         if (!mm_use_skey(mm) || pte_val(pte) & _PAGE_INVALID)
 118                 return pgste;
 119         address = pte_val(pte) & PAGE_MASK;
 120         skey = (unsigned long) page_get_storage_key(address);
 121         bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED);
 122         /* Transfer page changed & referenced bit to guest bits in pgste */
 123         pgste_val(pgste) |= bits << 48;         /* GR bit & GC bit */
 124         /* Copy page access key and fetch protection bit to pgste */
 125         pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT);
 126         pgste_val(pgste) |= (skey & (_PAGE_ACC_BITS | _PAGE_FP_BIT)) << 56;
 127 #endif
 128         return pgste;
 129
 130 }
 131
 132 static inline void pgste_set_key(pte_t *ptep, pgste_t pgste, pte_t entry,
 133                                  struct mm_struct *mm)
 134 {
 135 #ifdef CONFIG_PGSTE
 136         unsigned long address;
 137         unsigned long nkey;
 138
 139         if (!mm_use_skey(mm) || pte_val(entry) & _PAGE_INVALID)
 140                 return;
 141         VM_BUG_ON(!(pte_val(*ptep) & _PAGE_INVALID));
 142         address = pte_val(entry) & PAGE_MASK;
 143         /*
 144          * Set page access key and fetch protection bit from pgste.
 145          * The guest C/R information is still in the PGSTE, set real
 146          * key C/R to 0.
 147          */
 148         nkey = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
 149         nkey |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48;
 150         page_set_storage_key(address, nkey, 0);
 151 #endif
 152 }
 153
 154 static inline pgste_t pgste_set_pte(pte_t *ptep, pgste_t pgste, pte_t entry)
 155 {
 156 #ifdef CONFIG_PGSTE
 157         if ((pte_val(entry) & _PAGE_PRESENT) &&
 158             (pte_val(entry) & _PAGE_WRITE) &&
 159             !(pte_val(entry) & _PAGE_INVALID)) {
 160                 if (!MACHINE_HAS_ESOP) {
 161                         /*
 162                          * Without enhanced suppression-on-protection force
 163                          * the dirty bit on for all writable ptes.
 164                          */
 165                         pte_val(entry) |= _PAGE_DIRTY;
 166                         pte_val(entry) &= ~_PAGE_PROTECT;
 167                 }
 168                 if (!(pte_val(entry) & _PAGE_PROTECT))
 169                         /* This pte allows write access, set user-dirty */
 170                         pgste_val(pgste) |= PGSTE_UC_BIT;
 171         }
 172 #endif
 173         *ptep = entry;
 174         return pgste;
 175 }
 176
 177 static inline pgste_t pgste_pte_notify(struct mm_struct *mm,
 178                                        unsigned long addr,
 179                                        pte_t *ptep, pgste_t pgste)
 180 {
 181 #ifdef CONFIG_PGSTE
 182         unsigned long bits;
 183
 184         bits = pgste_val(pgste) & (PGSTE_IN_BIT | PGSTE_VSIE_BIT);
 185         if (bits) {
 186                 pgste_val(pgste) ^= bits;
 187                 ptep_notify(mm, addr, ptep, bits);
 188         }
 189 #endif
 190         return pgste;
 191 }
 192
 193 static inline pgste_t ptep_xchg_start(struct mm_struct *mm,
 194                                       unsigned long addr, pte_t *ptep)
 195 {
 196         pgste_t pgste = __pgste(0);
 197
 198         if (mm_has_pgste(mm)) {
 199                 pgste = pgste_get_lock(ptep);
 200                 pgste = pgste_pte_notify(mm, addr, ptep, pgste);
 201         }
 202         return pgste;
 203 }
 204
 205 static inline void ptep_xchg_commit(struct mm_struct *mm,
 206                                     unsigned long addr, pte_t *ptep,
 207                                     pgste_t pgste, pte_t old, pte_t new)
 208 {
 209         if (mm_has_pgste(mm)) {
 210                 if (pte_val(old) & _PAGE_INVALID)
 211                         pgste_set_key(ptep, pgste, new, mm);
 212                 if (pte_val(new) & _PAGE_INVALID) {
 213                         pgste = pgste_update_all(old, pgste, mm);
 214                         if ((pgste_val(pgste) & _PGSTE_GPS_USAGE_MASK) ==
 215                             _PGSTE_GPS_USAGE_UNUSED)
 216                                 pte_val(old) |= _PAGE_UNUSED;
 217                 }
 218                 pgste = pgste_set_pte(ptep, pgste, new);
 219                 pgste_set_unlock(ptep, pgste);
 220         } else {
 221                 *ptep = new;
 222         }
 223 }
 224
 225 pte_t ptep_xchg_direct(struct mm_struct *mm, unsigned long addr,
 226                        pte_t *ptep, pte_t new)
 227 {
 228         pgste_t pgste;
 229         pte_t old;
 230
 231         preempt_disable();
 232         pgste = ptep_xchg_start(mm, addr, ptep);
 233         old = ptep_flush_direct(mm, addr, ptep);
 234         ptep_xchg_commit(mm, addr, ptep, pgste, old, new);
 235         preempt_enable();
 236         return old;
 237 }
 238 EXPORT_SYMBOL(ptep_xchg_direct);
 239
 240 pte_t ptep_xchg_lazy(struct mm_struct *mm, unsigned long addr,
 241                      pte_t *ptep, pte_t new)
 242 {
 243         pgste_t pgste;
 244         pte_t old;
 245
 246         preempt_disable();
 247         pgste = ptep_xchg_start(mm, addr, ptep);
 248         old = ptep_flush_lazy(mm, addr, ptep);
 249         ptep_xchg_commit(mm, addr, ptep, pgste, old, new);
 250         preempt_enable();
 251         return old;
 252 }
 253 EXPORT_SYMBOL(ptep_xchg_lazy);
 254
 255 pte_t ptep_modify_prot_start(struct mm_struct *mm, unsigned long addr,
 256                              pte_t *ptep)
 257 {
 258         pgste_t pgste;
 259         pte_t old;
 260
 261         preempt_disable();
 262         pgste = ptep_xchg_start(mm, addr, ptep);
 263         old = ptep_flush_lazy(mm, addr, ptep);
 264         if (mm_has_pgste(mm)) {
 265                 pgste = pgste_update_all(old, pgste, mm);
 266                 pgste_set(ptep, pgste);
 267         }
 268         return old;
 269 }
 270 EXPORT_SYMBOL(ptep_modify_prot_start);
 271
 272 void ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
 273                              pte_t *ptep, pte_t pte)
 274 {
 275         pgste_t pgste;
 276
 277         if (mm_has_pgste(mm)) {
 278                 pgste = pgste_get(ptep);
 279                 pgste_set_key(ptep, pgste, pte, mm);
 280                 pgste = pgste_set_pte(ptep, pgste, pte);
 281                 pgste_set_unlock(ptep, pgste);
 282         } else {
 283                 *ptep = pte;
 284         }
 285         preempt_enable();
 286 }
 287 EXPORT_SYMBOL(ptep_modify_prot_commit);
 288
 289 static inline pmd_t pmdp_flush_direct(struct mm_struct *mm,
 290                                       unsigned long addr, pmd_t *pmdp)
 291 {
 292         pmd_t old;
 293
 294         old = *pmdp;
 295         if (pmd_val(old) & _SEGMENT_ENTRY_INVALID)
 296                 return old;
 297         if (!MACHINE_HAS_IDTE) {
 298                 __pmdp_csp(pmdp);
 299                 return old;
 300         }
 301         atomic_inc(&mm->context.flush_count);
 302         if (MACHINE_HAS_TLB_LC &&
 303             cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
 304                 __pmdp_idte(addr, pmdp, IDTE_LOCAL);
 305         else
 306                 __pmdp_idte(addr, pmdp, IDTE_GLOBAL);
 307         atomic_dec(&mm->context.flush_count);
 308         return old;
 309 }
 310
 311 static inline pmd_t pmdp_flush_lazy(struct mm_struct *mm,
 312                                     unsigned long addr, pmd_t *pmdp)
 313 {
 314         pmd_t old;
 315
 316         old = *pmdp;
 317         if (pmd_val(old) & _SEGMENT_ENTRY_INVALID)
 318                 return old;
 319         atomic_inc(&mm->context.flush_count);
 320         if (cpumask_equal(&mm->context.cpu_attach_mask,
 321                           cpumask_of(smp_processor_id()))) {
 322                 pmd_val(*pmdp) |= _SEGMENT_ENTRY_INVALID;
 323                 mm->context.flush_mm = 1;
 324         } else if (MACHINE_HAS_IDTE)
 325                 __pmdp_idte(addr, pmdp, IDTE_GLOBAL);
 326         else
 327                 __pmdp_csp(pmdp);
 328         atomic_dec(&mm->context.flush_count);
 329         return old;
 330 }
 331
 332 pmd_t pmdp_xchg_direct(struct mm_struct *mm, unsigned long addr,
 333                        pmd_t *pmdp, pmd_t new)
 334 {
 335         pmd_t old;
 336
 337         preempt_disable();
 338         old = pmdp_flush_direct(mm, addr, pmdp);
 339         *pmdp = new;
 340         preempt_enable();
 341         return old;
 342 }
 343 EXPORT_SYMBOL(pmdp_xchg_direct);
 344
 345 pmd_t pmdp_xchg_lazy(struct mm_struct *mm, unsigned long addr,
 346                      pmd_t *pmdp, pmd_t new)
 347 {
 348         pmd_t old;
 349
 350         preempt_disable();
 351         old = pmdp_flush_lazy(mm, addr, pmdp);
 352         *pmdp = new;
 353         preempt_enable();
 354         return old;
 355 }
 356 EXPORT_SYMBOL(pmdp_xchg_lazy);
 357
 358 static inline pud_t pudp_flush_direct(struct mm_struct *mm,
 359                                       unsigned long addr, pud_t *pudp)
 360 {
 361         pud_t old;
 362
 363         old = *pudp;
 364         if (pud_val(old) & _REGION_ENTRY_INVALID)
 365                 return old;
 366         if (!MACHINE_HAS_IDTE) {
 367                 /*
 368                  * Invalid bit position is the same for pmd and pud, so we can
 369                  * re-use _pmd_csp() here
 370                  */
 371                 __pmdp_csp((pmd_t *) pudp);
 372                 return old;
 373         }
 374         atomic_inc(&mm->context.flush_count);
 375         if (MACHINE_HAS_TLB_LC &&
 376             cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
 377                 __pudp_idte(addr, pudp, IDTE_LOCAL);
 378         else
 379                 __pudp_idte(addr, pudp, IDTE_GLOBAL);
 380         atomic_dec(&mm->context.flush_count);
 381         return old;
 382 }
 383
 384 pud_t pudp_xchg_direct(struct mm_struct *mm, unsigned long addr,
 385                        pud_t *pudp, pud_t new)
 386 {
 387         pud_t old;
 388
 389         preempt_disable();
 390         old = pudp_flush_direct(mm, addr, pudp);
 391         *pudp = new;
 392         preempt_enable();
 393         return old;
 394 }
 395 EXPORT_SYMBOL(pudp_xchg_direct);
 396
 397 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 398 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 399                                 pgtable_t pgtable)
 400 {
 401         struct list_head *lh = (struct list_head *) pgtable;
 402
 403         assert_spin_locked(pmd_lockptr(mm, pmdp));
 404
 405         /* FIFO */
 406         if (!pmd_huge_pte(mm, pmdp))
 407                 INIT_LIST_HEAD(lh);
 408         else
 409                 list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
 410         pmd_huge_pte(mm, pmdp) = pgtable;
 411 }
 412
 413 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 414 {
 415         struct list_head *lh;
 416         pgtable_t pgtable;
 417         pte_t *ptep;
 418
 419         assert_spin_locked(pmd_lockptr(mm, pmdp));
 420
 421         /* FIFO */
 422         pgtable = pmd_huge_pte(mm, pmdp);
 423         lh = (struct list_head *) pgtable;
 424         if (list_empty(lh))
 425                 pmd_huge_pte(mm, pmdp) = NULL;
 426         else {
 427                 pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
 428                 list_del(lh);
 429         }
 430         ptep = (pte_t *) pgtable;
 431         pte_val(*ptep) = _PAGE_INVALID;
 432         ptep++;
 433         pte_val(*ptep) = _PAGE_INVALID;
 434         return pgtable;
 435 }
 436 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 437
 438 #ifdef CONFIG_PGSTE
 439 void ptep_set_pte_at(struct mm_struct *mm, unsigned long addr,
 440                      pte_t *ptep, pte_t entry)
 441 {
 442         pgste_t pgste;
 443
 444         /* the mm_has_pgste() check is done in set_pte_at() */
 445         preempt_disable();
 446         pgste = pgste_get_lock(ptep);
 447         pgste_val(pgste) &= ~_PGSTE_GPS_ZERO;
 448         pgste_set_key(ptep, pgste, entry, mm);
 449         pgste = pgste_set_pte(ptep, pgste, entry);
 450         pgste_set_unlock(ptep, pgste);
 451         preempt_enable();
 452 }
 453
 454 void ptep_set_notify(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 455 {
 456         pgste_t pgste;
 457
 458         preempt_disable();
 459         pgste = pgste_get_lock(ptep);
 460         pgste_val(pgste) |= PGSTE_IN_BIT;
 461         pgste_set_unlock(ptep, pgste);
 462         preempt_enable();
 463 }
 464
 465 /**
 466  * ptep_force_prot - change access rights of a locked pte
 467  * @mm: pointer to the process mm_struct
 468  * @addr: virtual address in the guest address space
 469  * @ptep: pointer to the page table entry
 470  * @prot: indicates guest access rights: PROT_NONE, PROT_READ or PROT_WRITE
 471  * @bit: pgste bit to set (e.g. for notification)
 472  *
 473  * Returns 0 if the access rights were changed and -EAGAIN if the current
 474  * and requested access rights are incompatible.
 475  */
 476 int ptep_force_prot(struct mm_struct *mm, unsigned long addr,
 477                     pte_t *ptep, int prot, unsigned long bit)
 478 {
 479         pte_t entry;
 480         pgste_t pgste;
 481         int pte_i, pte_p;
 482
 483         pgste = pgste_get_lock(ptep);
 484         entry = *ptep;
 485         /* Check pte entry after all locks have been acquired */
 486         pte_i = pte_val(entry) & _PAGE_INVALID;
 487         pte_p = pte_val(entry) & _PAGE_PROTECT;
 488         if ((pte_i && (prot != PROT_NONE)) ||
 489             (pte_p && (prot & PROT_WRITE))) {
 490                 pgste_set_unlock(ptep, pgste);
 491                 return -EAGAIN;
 492         }
 493         /* Change access rights and set pgste bit */
 494         if (prot == PROT_NONE && !pte_i) {
 495                 ptep_flush_direct(mm, addr, ptep);
 496                 pgste = pgste_update_all(entry, pgste, mm);
 497                 pte_val(entry) |= _PAGE_INVALID;
 498         }
 499         if (prot == PROT_READ && !pte_p) {
 500                 ptep_flush_direct(mm, addr, ptep);
 501                 pte_val(entry) &= ~_PAGE_INVALID;
 502                 pte_val(entry) |= _PAGE_PROTECT;
 503         }
 504         pgste_val(pgste) |= bit;
 505         pgste = pgste_set_pte(ptep, pgste, entry);
 506         pgste_set_unlock(ptep, pgste);
 507         return 0;
 508 }
 509
 510 int ptep_shadow_pte(struct mm_struct *mm, unsigned long saddr,
 511                     pte_t *sptep, pte_t *tptep, pte_t pte)
 512 {
 513         pgste_t spgste, tpgste;
 514         pte_t spte, tpte;
 515         int rc = -EAGAIN;
 516
 517         if (!(pte_val(*tptep) & _PAGE_INVALID))
 518                 return 0;       /* already shadowed */
 519         spgste = pgste_get_lock(sptep);
 520         spte = *sptep;
 521         if (!(pte_val(spte) & _PAGE_INVALID) &&
 522             !((pte_val(spte) & _PAGE_PROTECT) &&
 523               !(pte_val(pte) & _PAGE_PROTECT))) {
 524                 pgste_val(spgste) |= PGSTE_VSIE_BIT;
 525                 tpgste = pgste_get_lock(tptep);
 526                 pte_val(tpte) = (pte_val(spte) & PAGE_MASK) |
 527                                 (pte_val(pte) & _PAGE_PROTECT);
 528                 /* don't touch the storage key - it belongs to parent pgste */
 529                 tpgste = pgste_set_pte(tptep, tpgste, tpte);
 530                 pgste_set_unlock(tptep, tpgste);
 531                 rc = 1;
 532         }
 533         pgste_set_unlock(sptep, spgste);
 534         return rc;
 535 }
 536
 537 void ptep_unshadow_pte(struct mm_struct *mm, unsigned long saddr, pte_t *ptep)
 538 {
 539         pgste_t pgste;
 540
 541         pgste = pgste_get_lock(ptep);
 542         /* notifier is called by the caller */
 543         ptep_flush_direct(mm, saddr, ptep);
 544         /* don't touch the storage key - it belongs to parent pgste */
 545         pgste = pgste_set_pte(ptep, pgste, __pte(_PAGE_INVALID));
 546         pgste_set_unlock(ptep, pgste);
 547 }
 548
 549 static void ptep_zap_swap_entry(struct mm_struct *mm, swp_entry_t entry)
 550 {
 551         if (!non_swap_entry(entry))
 552                 dec_mm_counter(mm, MM_SWAPENTS);
 553         else if (is_migration_entry(entry)) {
 554                 struct page *page = migration_entry_to_page(entry);
 555
 556                 dec_mm_counter(mm, mm_counter(page));
 557         }
 558         free_swap_and_cache(entry);
 559 }
 560
 561 void ptep_zap_unused(struct mm_struct *mm, unsigned long addr,
 562                      pte_t *ptep, int reset)
 563 {
 564         unsigned long pgstev;
 565         pgste_t pgste;
 566         pte_t pte;
 567
 568         /* Zap unused and logically-zero pages */
 569         preempt_disable();
 570         pgste = pgste_get_lock(ptep);
 571         pgstev = pgste_val(pgste);
 572         pte = *ptep;
 573         if (!reset && pte_swap(pte) &&
 574             ((pgstev & _PGSTE_GPS_USAGE_MASK) == _PGSTE_GPS_USAGE_UNUSED ||
 575              (pgstev & _PGSTE_GPS_ZERO))) {
 576                 ptep_zap_swap_entry(mm, pte_to_swp_entry(pte));
 577                 pte_clear(mm, addr, ptep);
 578         }
 579         if (reset)
 580                 pgste_val(pgste) &= ~_PGSTE_GPS_USAGE_MASK;
 581         pgste_set_unlock(ptep, pgste);
 582         preempt_enable();
 583 }
 584
 585 void ptep_zap_key(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 586 {
 587         unsigned long ptev;
 588         pgste_t pgste;
 589
 590         /* Clear storage key */
 591         preempt_disable();
 592         pgste = pgste_get_lock(ptep);
 593         pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT |
 594                               PGSTE_GR_BIT | PGSTE_GC_BIT);
 595         ptev = pte_val(*ptep);
 596         if (!(ptev & _PAGE_INVALID) && (ptev & _PAGE_WRITE))
 597                 page_set_storage_key(ptev & PAGE_MASK, PAGE_DEFAULT_KEY, 1);
 598         pgste_set_unlock(ptep, pgste);
 599         preempt_enable();
 600 }
 601
 602 /*
 603  * Test and reset if a guest page is dirty
 604  */
 605 bool test_and_clear_guest_dirty(struct mm_struct *mm, unsigned long addr)
 606 {
 607         spinlock_t *ptl;
 608         pgste_t pgste;
 609         pte_t *ptep;
 610         pte_t pte;
 611         bool dirty;
 612
 613         ptep = get_locked_pte(mm, addr, &ptl);
 614         if (unlikely(!ptep))
 615                 return false;
 616
 617         pgste = pgste_get_lock(ptep);
 618         dirty = !!(pgste_val(pgste) & PGSTE_UC_BIT);
 619         pgste_val(pgste) &= ~PGSTE_UC_BIT;
 620         pte = *ptep;
 621         if (dirty && (pte_val(pte) & _PAGE_PRESENT)) {
 622                 pgste = pgste_pte_notify(mm, addr, ptep, pgste);
 623                 __ptep_ipte(addr, ptep, IPTE_GLOBAL);
 624                 if (MACHINE_HAS_ESOP || !(pte_val(pte) & _PAGE_WRITE))
 625                         pte_val(pte) |= _PAGE_PROTECT;
 626                 else
 627                         pte_val(pte) |= _PAGE_INVALID;
 628                 *ptep = pte;
 629         }
 630         pgste_set_unlock(ptep, pgste);
 631
 632         spin_unlock(ptl);
 633         return dirty;
 634 }
 635 EXPORT_SYMBOL_GPL(test_and_clear_guest_dirty);
 636
 637 int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 638                           unsigned char key, bool nq)
 639 {
 640         unsigned long keyul;
 641         spinlock_t *ptl;
 642         pgste_t old, new;
 643         pte_t *ptep;
 644
 645         ptep = get_locked_pte(mm, addr, &ptl);
 646         if (unlikely(!ptep))
 647                 return -EFAULT;
 648
 649         new = old = pgste_get_lock(ptep);
 650         pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT |
 651                             PGSTE_ACC_BITS | PGSTE_FP_BIT);
 652         keyul = (unsigned long) key;
 653         pgste_val(new) |= (keyul & (_PAGE_CHANGED | _PAGE_REFERENCED)) << 48;
 654         pgste_val(new) |= (keyul & (_PAGE_ACC_BITS | _PAGE_FP_BIT)) << 56;
 655         if (!(pte_val(*ptep) & _PAGE_INVALID)) {
 656                 unsigned long address, bits, skey;
 657
 658                 address = pte_val(*ptep) & PAGE_MASK;
 659                 skey = (unsigned long) page_get_storage_key(address);
 660                 bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED);
 661                 skey = key & (_PAGE_ACC_BITS | _PAGE_FP_BIT);
 662                 /* Set storage key ACC and FP */
 663                 page_set_storage_key(address, skey, !nq);
 664                 /* Merge host changed & referenced into pgste  */
 665                 pgste_val(new) |= bits << 52;
 666         }
 667         /* changing the guest storage key is considered a change of the page */
 668         if ((pgste_val(new) ^ pgste_val(old)) &
 669             (PGSTE_ACC_BITS | PGSTE_FP_BIT | PGSTE_GR_BIT | PGSTE_GC_BIT))
 670                 pgste_val(new) |= PGSTE_UC_BIT;
 671
 672         pgste_set_unlock(ptep, new);
 673         pte_unmap_unlock(ptep, ptl);
 674         return 0;
 675 }
 676 EXPORT_SYMBOL(set_guest_storage_key);
 677
 678 /**
 679  * Conditionally set a guest storage key (handling csske).
 680  * oldkey will be updated when either mr or mc is set and a pointer is given.
 681  *
 682  * Returns 0 if a guests storage key update wasn't necessary, 1 if the guest
 683  * storage key was updated and -EFAULT on access errors.
 684  */
 685 int cond_set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 686                                unsigned char key, unsigned char *oldkey,
 687                                bool nq, bool mr, bool mc)
 688 {
 689         unsigned char tmp, mask = _PAGE_ACC_BITS | _PAGE_FP_BIT;
 690         int rc;
 691
 692         /* we can drop the pgste lock between getting and setting the key */
 693         if (mr | mc) {
 694                 rc = get_guest_storage_key(current->mm, addr, &tmp);
 695                 if (rc)
 696                         return rc;
 697                 if (oldkey)
 698                         *oldkey = tmp;
 699                 if (!mr)
 700                         mask |= _PAGE_REFERENCED;
 701                 if (!mc)
 702                         mask |= _PAGE_CHANGED;
 703                 if (!((tmp ^ key) & mask))
 704                         return 0;
 705         }
 706         rc = set_guest_storage_key(current->mm, addr, key, nq);
 707         return rc < 0 ? rc : 1;
 708 }
 709 EXPORT_SYMBOL(cond_set_guest_storage_key);
 710
 711 /**
 712  * Reset a guest reference bit (rrbe), returning the reference and changed bit.
 713  *
 714  * Returns < 0 in case of error, otherwise the cc to be reported to the guest.
 715  */
 716 int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr)
 717 {
 718         spinlock_t *ptl;
 719         pgste_t old, new;
 720         pte_t *ptep;
 721         int cc = 0;
 722
 723         ptep = get_locked_pte(mm, addr, &ptl);
 724         if (unlikely(!ptep))
 725                 return -EFAULT;
 726
 727         new = old = pgste_get_lock(ptep);
 728         /* Reset guest reference bit only */
 729         pgste_val(new) &= ~PGSTE_GR_BIT;
 730
 731         if (!(pte_val(*ptep) & _PAGE_INVALID)) {
 732                 cc = page_reset_referenced(pte_val(*ptep) & PAGE_MASK);
 733                 /* Merge real referenced bit into host-set */
 734                 pgste_val(new) |= ((unsigned long) cc << 53) & PGSTE_HR_BIT;
 735         }
 736         /* Reflect guest's logical view, not physical */
 737         cc |= (pgste_val(old) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 49;
 738         /* Changing the guest storage key is considered a change of the page */
 739         if ((pgste_val(new) ^ pgste_val(old)) & PGSTE_GR_BIT)
 740                 pgste_val(new) |= PGSTE_UC_BIT;
 741
 742         pgste_set_unlock(ptep, new);
 743         pte_unmap_unlock(ptep, ptl);
 744         return 0;
 745 }
 746 EXPORT_SYMBOL(reset_guest_reference_bit);
 747
 748 int get_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 749                           unsigned char *key)
 750 {
 751         spinlock_t *ptl;
 752         pgste_t pgste;
 753         pte_t *ptep;
 754
 755         ptep = get_locked_pte(mm, addr, &ptl);
 756         if (unlikely(!ptep))
 757                 return -EFAULT;
 758
 759         pgste = pgste_get_lock(ptep);
 760         *key = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
 761         if (!(pte_val(*ptep) & _PAGE_INVALID))
 762                 *key = page_get_storage_key(pte_val(*ptep) & PAGE_MASK);
 763         /* Reflect guest's logical view, not physical */
 764         *key |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48;
 765         pgste_set_unlock(ptep, pgste);
 766         pte_unmap_unlock(ptep, ptl);
 767         return 0;
 768 }
 769 EXPORT_SYMBOL(get_guest_storage_key);
 770 #endif