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 pte_t 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         return old;
 224 }
 225
 226 pte_t ptep_xchg_direct(struct mm_struct *mm, unsigned long addr,
 227                        pte_t *ptep, pte_t new)
 228 {
 229         pgste_t pgste;
 230         pte_t old;
 231
 232         preempt_disable();
 233         pgste = ptep_xchg_start(mm, addr, ptep);
 234         old = ptep_flush_direct(mm, addr, ptep);
 235         old = ptep_xchg_commit(mm, addr, ptep, pgste, old, new);
 236         preempt_enable();
 237         return old;
 238 }
 239 EXPORT_SYMBOL(ptep_xchg_direct);
 240
 241 pte_t ptep_xchg_lazy(struct mm_struct *mm, unsigned long addr,
 242                      pte_t *ptep, pte_t new)
 243 {
 244         pgste_t pgste;
 245         pte_t old;
 246
 247         preempt_disable();
 248         pgste = ptep_xchg_start(mm, addr, ptep);
 249         old = ptep_flush_lazy(mm, addr, ptep);
 250         old = ptep_xchg_commit(mm, addr, ptep, pgste, old, new);
 251         preempt_enable();
 252         return old;
 253 }
 254 EXPORT_SYMBOL(ptep_xchg_lazy);
 255
 256 pte_t ptep_modify_prot_start(struct mm_struct *mm, unsigned long addr,
 257                              pte_t *ptep)
 258 {
 259         pgste_t pgste;
 260         pte_t old;
 261
 262         preempt_disable();
 263         pgste = ptep_xchg_start(mm, addr, ptep);
 264         old = ptep_flush_lazy(mm, addr, ptep);
 265         if (mm_has_pgste(mm)) {
 266                 pgste = pgste_update_all(old, pgste, mm);
 267                 pgste_set(ptep, pgste);
 268         }
 269         return old;
 270 }
 271 EXPORT_SYMBOL(ptep_modify_prot_start);
 272
 273 void ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
 274                              pte_t *ptep, pte_t pte)
 275 {
 276         pgste_t pgste;
 277
 278         if (!MACHINE_HAS_NX)
 279                 pte_val(pte) &= ~_PAGE_NOEXEC;
 280         if (mm_has_pgste(mm)) {
 281                 pgste = pgste_get(ptep);
 282                 pgste_set_key(ptep, pgste, pte, mm);
 283                 pgste = pgste_set_pte(ptep, pgste, pte);
 284                 pgste_set_unlock(ptep, pgste);
 285         } else {
 286                 *ptep = pte;
 287         }
 288         preempt_enable();
 289 }
 290 EXPORT_SYMBOL(ptep_modify_prot_commit);
 291
 292 static inline pmd_t pmdp_flush_direct(struct mm_struct *mm,
 293                                       unsigned long addr, pmd_t *pmdp)
 294 {
 295         pmd_t old;
 296
 297         old = *pmdp;
 298         if (pmd_val(old) & _SEGMENT_ENTRY_INVALID)
 299                 return old;
 300         if (!MACHINE_HAS_IDTE) {
 301                 __pmdp_csp(pmdp);
 302                 return old;
 303         }
 304         atomic_inc(&mm->context.flush_count);
 305         if (MACHINE_HAS_TLB_LC &&
 306             cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
 307                 __pmdp_idte(addr, pmdp, IDTE_LOCAL);
 308         else
 309                 __pmdp_idte(addr, pmdp, IDTE_GLOBAL);
 310         atomic_dec(&mm->context.flush_count);
 311         return old;
 312 }
 313
 314 static inline pmd_t pmdp_flush_lazy(struct mm_struct *mm,
 315                                     unsigned long addr, pmd_t *pmdp)
 316 {
 317         pmd_t old;
 318
 319         old = *pmdp;
 320         if (pmd_val(old) & _SEGMENT_ENTRY_INVALID)
 321                 return old;
 322         atomic_inc(&mm->context.flush_count);
 323         if (cpumask_equal(&mm->context.cpu_attach_mask,
 324                           cpumask_of(smp_processor_id()))) {
 325                 pmd_val(*pmdp) |= _SEGMENT_ENTRY_INVALID;
 326                 mm->context.flush_mm = 1;
 327         } else if (MACHINE_HAS_IDTE)
 328                 __pmdp_idte(addr, pmdp, IDTE_GLOBAL);
 329         else
 330                 __pmdp_csp(pmdp);
 331         atomic_dec(&mm->context.flush_count);
 332         return old;
 333 }
 334
 335 pmd_t pmdp_xchg_direct(struct mm_struct *mm, unsigned long addr,
 336                        pmd_t *pmdp, pmd_t new)
 337 {
 338         pmd_t old;
 339
 340         preempt_disable();
 341         old = pmdp_flush_direct(mm, addr, pmdp);
 342         *pmdp = new;
 343         preempt_enable();
 344         return old;
 345 }
 346 EXPORT_SYMBOL(pmdp_xchg_direct);
 347
 348 pmd_t pmdp_xchg_lazy(struct mm_struct *mm, unsigned long addr,
 349                      pmd_t *pmdp, pmd_t new)
 350 {
 351         pmd_t old;
 352
 353         preempt_disable();
 354         old = pmdp_flush_lazy(mm, addr, pmdp);
 355         *pmdp = new;
 356         preempt_enable();
 357         return old;
 358 }
 359 EXPORT_SYMBOL(pmdp_xchg_lazy);
 360
 361 static inline pud_t pudp_flush_direct(struct mm_struct *mm,
 362                                       unsigned long addr, pud_t *pudp)
 363 {
 364         pud_t old;
 365
 366         old = *pudp;
 367         if (pud_val(old) & _REGION_ENTRY_INVALID)
 368                 return old;
 369         if (!MACHINE_HAS_IDTE) {
 370                 /*
 371                  * Invalid bit position is the same for pmd and pud, so we can
 372                  * re-use _pmd_csp() here
 373                  */
 374                 __pmdp_csp((pmd_t *) pudp);
 375                 return old;
 376         }
 377         atomic_inc(&mm->context.flush_count);
 378         if (MACHINE_HAS_TLB_LC &&
 379             cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
 380                 __pudp_idte(addr, pudp, IDTE_LOCAL);
 381         else
 382                 __pudp_idte(addr, pudp, IDTE_GLOBAL);
 383         atomic_dec(&mm->context.flush_count);
 384         return old;
 385 }
 386
 387 pud_t pudp_xchg_direct(struct mm_struct *mm, unsigned long addr,
 388                        pud_t *pudp, pud_t new)
 389 {
 390         pud_t old;
 391
 392         preempt_disable();
 393         old = pudp_flush_direct(mm, addr, pudp);
 394         *pudp = new;
 395         preempt_enable();
 396         return old;
 397 }
 398 EXPORT_SYMBOL(pudp_xchg_direct);
 399
 400 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 401 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 402                                 pgtable_t pgtable)
 403 {
 404         struct list_head *lh = (struct list_head *) pgtable;
 405
 406         assert_spin_locked(pmd_lockptr(mm, pmdp));
 407
 408         /* FIFO */
 409         if (!pmd_huge_pte(mm, pmdp))
 410                 INIT_LIST_HEAD(lh);
 411         else
 412                 list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
 413         pmd_huge_pte(mm, pmdp) = pgtable;
 414 }
 415
 416 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 417 {
 418         struct list_head *lh;
 419         pgtable_t pgtable;
 420         pte_t *ptep;
 421
 422         assert_spin_locked(pmd_lockptr(mm, pmdp));
 423
 424         /* FIFO */
 425         pgtable = pmd_huge_pte(mm, pmdp);
 426         lh = (struct list_head *) pgtable;
 427         if (list_empty(lh))
 428                 pmd_huge_pte(mm, pmdp) = NULL;
 429         else {
 430                 pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
 431                 list_del(lh);
 432         }
 433         ptep = (pte_t *) pgtable;
 434         pte_val(*ptep) = _PAGE_INVALID;
 435         ptep++;
 436         pte_val(*ptep) = _PAGE_INVALID;
 437         return pgtable;
 438 }
 439 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 440
 441 #ifdef CONFIG_PGSTE
 442 void ptep_set_pte_at(struct mm_struct *mm, unsigned long addr,
 443                      pte_t *ptep, pte_t entry)
 444 {
 445         pgste_t pgste;
 446
 447         /* the mm_has_pgste() check is done in set_pte_at() */
 448         preempt_disable();
 449         pgste = pgste_get_lock(ptep);
 450         pgste_val(pgste) &= ~_PGSTE_GPS_ZERO;
 451         pgste_set_key(ptep, pgste, entry, mm);
 452         pgste = pgste_set_pte(ptep, pgste, entry);
 453         pgste_set_unlock(ptep, pgste);
 454         preempt_enable();
 455 }
 456
 457 void ptep_set_notify(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 458 {
 459         pgste_t pgste;
 460
 461         preempt_disable();
 462         pgste = pgste_get_lock(ptep);
 463         pgste_val(pgste) |= PGSTE_IN_BIT;
 464         pgste_set_unlock(ptep, pgste);
 465         preempt_enable();
 466 }
 467
 468 /**
 469  * ptep_force_prot - change access rights of a locked pte
 470  * @mm: pointer to the process mm_struct
 471  * @addr: virtual address in the guest address space
 472  * @ptep: pointer to the page table entry
 473  * @prot: indicates guest access rights: PROT_NONE, PROT_READ or PROT_WRITE
 474  * @bit: pgste bit to set (e.g. for notification)
 475  *
 476  * Returns 0 if the access rights were changed and -EAGAIN if the current
 477  * and requested access rights are incompatible.
 478  */
 479 int ptep_force_prot(struct mm_struct *mm, unsigned long addr,
 480                     pte_t *ptep, int prot, unsigned long bit)
 481 {
 482         pte_t entry;
 483         pgste_t pgste;
 484         int pte_i, pte_p;
 485
 486         pgste = pgste_get_lock(ptep);
 487         entry = *ptep;
 488         /* Check pte entry after all locks have been acquired */
 489         pte_i = pte_val(entry) & _PAGE_INVALID;
 490         pte_p = pte_val(entry) & _PAGE_PROTECT;
 491         if ((pte_i && (prot != PROT_NONE)) ||
 492             (pte_p && (prot & PROT_WRITE))) {
 493                 pgste_set_unlock(ptep, pgste);
 494                 return -EAGAIN;
 495         }
 496         /* Change access rights and set pgste bit */
 497         if (prot == PROT_NONE && !pte_i) {
 498                 ptep_flush_direct(mm, addr, ptep);
 499                 pgste = pgste_update_all(entry, pgste, mm);
 500                 pte_val(entry) |= _PAGE_INVALID;
 501         }
 502         if (prot == PROT_READ && !pte_p) {
 503                 ptep_flush_direct(mm, addr, ptep);
 504                 pte_val(entry) &= ~_PAGE_INVALID;
 505                 pte_val(entry) |= _PAGE_PROTECT;
 506         }
 507         pgste_val(pgste) |= bit;
 508         pgste = pgste_set_pte(ptep, pgste, entry);
 509         pgste_set_unlock(ptep, pgste);
 510         return 0;
 511 }
 512
 513 int ptep_shadow_pte(struct mm_struct *mm, unsigned long saddr,
 514                     pte_t *sptep, pte_t *tptep, pte_t pte)
 515 {
 516         pgste_t spgste, tpgste;
 517         pte_t spte, tpte;
 518         int rc = -EAGAIN;
 519
 520         if (!(pte_val(*tptep) & _PAGE_INVALID))
 521                 return 0;       /* already shadowed */
 522         spgste = pgste_get_lock(sptep);
 523         spte = *sptep;
 524         if (!(pte_val(spte) & _PAGE_INVALID) &&
 525             !((pte_val(spte) & _PAGE_PROTECT) &&
 526               !(pte_val(pte) & _PAGE_PROTECT))) {
 527                 pgste_val(spgste) |= PGSTE_VSIE_BIT;
 528                 tpgste = pgste_get_lock(tptep);
 529                 pte_val(tpte) = (pte_val(spte) & PAGE_MASK) |
 530                                 (pte_val(pte) & _PAGE_PROTECT);
 531                 /* don't touch the storage key - it belongs to parent pgste */
 532                 tpgste = pgste_set_pte(tptep, tpgste, tpte);
 533                 pgste_set_unlock(tptep, tpgste);
 534                 rc = 1;
 535         }
 536         pgste_set_unlock(sptep, spgste);
 537         return rc;
 538 }
 539
 540 void ptep_unshadow_pte(struct mm_struct *mm, unsigned long saddr, pte_t *ptep)
 541 {
 542         pgste_t pgste;
 543
 544         pgste = pgste_get_lock(ptep);
 545         /* notifier is called by the caller */
 546         ptep_flush_direct(mm, saddr, ptep);
 547         /* don't touch the storage key - it belongs to parent pgste */
 548         pgste = pgste_set_pte(ptep, pgste, __pte(_PAGE_INVALID));
 549         pgste_set_unlock(ptep, pgste);
 550 }
 551
 552 static void ptep_zap_swap_entry(struct mm_struct *mm, swp_entry_t entry)
 553 {
 554         if (!non_swap_entry(entry))
 555                 dec_mm_counter(mm, MM_SWAPENTS);
 556         else if (is_migration_entry(entry)) {
 557                 struct page *page = migration_entry_to_page(entry);
 558
 559                 dec_mm_counter(mm, mm_counter(page));
 560         }
 561         free_swap_and_cache(entry);
 562 }
 563
 564 void ptep_zap_unused(struct mm_struct *mm, unsigned long addr,
 565                      pte_t *ptep, int reset)
 566 {
 567         unsigned long pgstev;
 568         pgste_t pgste;
 569         pte_t pte;
 570
 571         /* Zap unused and logically-zero pages */
 572         preempt_disable();
 573         pgste = pgste_get_lock(ptep);
 574         pgstev = pgste_val(pgste);
 575         pte = *ptep;
 576         if (!reset && pte_swap(pte) &&
 577             ((pgstev & _PGSTE_GPS_USAGE_MASK) == _PGSTE_GPS_USAGE_UNUSED ||
 578              (pgstev & _PGSTE_GPS_ZERO))) {
 579                 ptep_zap_swap_entry(mm, pte_to_swp_entry(pte));
 580                 pte_clear(mm, addr, ptep);
 581         }
 582         if (reset)
 583                 pgste_val(pgste) &= ~_PGSTE_GPS_USAGE_MASK;
 584         pgste_set_unlock(ptep, pgste);
 585         preempt_enable();
 586 }
 587
 588 void ptep_zap_key(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 589 {
 590         unsigned long ptev;
 591         pgste_t pgste;
 592
 593         /* Clear storage key */
 594         preempt_disable();
 595         pgste = pgste_get_lock(ptep);
 596         pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT |
 597                               PGSTE_GR_BIT | PGSTE_GC_BIT);
 598         ptev = pte_val(*ptep);
 599         if (!(ptev & _PAGE_INVALID) && (ptev & _PAGE_WRITE))
 600                 page_set_storage_key(ptev & PAGE_MASK, PAGE_DEFAULT_KEY, 1);
 601         pgste_set_unlock(ptep, pgste);
 602         preempt_enable();
 603 }
 604
 605 /*
 606  * Test and reset if a guest page is dirty
 607  */
 608 bool test_and_clear_guest_dirty(struct mm_struct *mm, unsigned long addr)
 609 {
 610         spinlock_t *ptl;
 611         pgste_t pgste;
 612         pte_t *ptep;
 613         pte_t pte;
 614         bool dirty;
 615
 616         ptep = get_locked_pte(mm, addr, &ptl);
 617         if (unlikely(!ptep))
 618                 return false;
 619
 620         pgste = pgste_get_lock(ptep);
 621         dirty = !!(pgste_val(pgste) & PGSTE_UC_BIT);
 622         pgste_val(pgste) &= ~PGSTE_UC_BIT;
 623         pte = *ptep;
 624         if (dirty && (pte_val(pte) & _PAGE_PRESENT)) {
 625                 pgste = pgste_pte_notify(mm, addr, ptep, pgste);
 626                 __ptep_ipte(addr, ptep, IPTE_GLOBAL);
 627                 if (MACHINE_HAS_ESOP || !(pte_val(pte) & _PAGE_WRITE))
 628                         pte_val(pte) |= _PAGE_PROTECT;
 629                 else
 630                         pte_val(pte) |= _PAGE_INVALID;
 631                 *ptep = pte;
 632         }
 633         pgste_set_unlock(ptep, pgste);
 634
 635         spin_unlock(ptl);
 636         return dirty;
 637 }
 638 EXPORT_SYMBOL_GPL(test_and_clear_guest_dirty);
 639
 640 int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 641                           unsigned char key, bool nq)
 642 {
 643         unsigned long keyul;
 644         spinlock_t *ptl;
 645         pgste_t old, new;
 646         pte_t *ptep;
 647
 648         ptep = get_locked_pte(mm, addr, &ptl);
 649         if (unlikely(!ptep))
 650                 return -EFAULT;
 651
 652         new = old = pgste_get_lock(ptep);
 653         pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT |
 654                             PGSTE_ACC_BITS | PGSTE_FP_BIT);
 655         keyul = (unsigned long) key;
 656         pgste_val(new) |= (keyul & (_PAGE_CHANGED | _PAGE_REFERENCED)) << 48;
 657         pgste_val(new) |= (keyul & (_PAGE_ACC_BITS | _PAGE_FP_BIT)) << 56;
 658         if (!(pte_val(*ptep) & _PAGE_INVALID)) {
 659                 unsigned long address, bits, skey;
 660
 661                 address = pte_val(*ptep) & PAGE_MASK;
 662                 skey = (unsigned long) page_get_storage_key(address);
 663                 bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED);
 664                 skey = key & (_PAGE_ACC_BITS | _PAGE_FP_BIT);
 665                 /* Set storage key ACC and FP */
 666                 page_set_storage_key(address, skey, !nq);
 667                 /* Merge host changed & referenced into pgste  */
 668                 pgste_val(new) |= bits << 52;
 669         }
 670         /* changing the guest storage key is considered a change of the page */
 671         if ((pgste_val(new) ^ pgste_val(old)) &
 672             (PGSTE_ACC_BITS | PGSTE_FP_BIT | PGSTE_GR_BIT | PGSTE_GC_BIT))
 673                 pgste_val(new) |= PGSTE_UC_BIT;
 674
 675         pgste_set_unlock(ptep, new);
 676         pte_unmap_unlock(ptep, ptl);
 677         return 0;
 678 }
 679 EXPORT_SYMBOL(set_guest_storage_key);
 680
 681 /**
 682  * Conditionally set a guest storage key (handling csske).
 683  * oldkey will be updated when either mr or mc is set and a pointer is given.
 684  *
 685  * Returns 0 if a guests storage key update wasn't necessary, 1 if the guest
 686  * storage key was updated and -EFAULT on access errors.
 687  */
 688 int cond_set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 689                                unsigned char key, unsigned char *oldkey,
 690                                bool nq, bool mr, bool mc)
 691 {
 692         unsigned char tmp, mask = _PAGE_ACC_BITS | _PAGE_FP_BIT;
 693         int rc;
 694
 695         /* we can drop the pgste lock between getting and setting the key */
 696         if (mr | mc) {
 697                 rc = get_guest_storage_key(current->mm, addr, &tmp);
 698                 if (rc)
 699                         return rc;
 700                 if (oldkey)
 701                         *oldkey = tmp;
 702                 if (!mr)
 703                         mask |= _PAGE_REFERENCED;
 704                 if (!mc)
 705                         mask |= _PAGE_CHANGED;
 706                 if (!((tmp ^ key) & mask))
 707                         return 0;
 708         }
 709         rc = set_guest_storage_key(current->mm, addr, key, nq);
 710         return rc < 0 ? rc : 1;
 711 }
 712 EXPORT_SYMBOL(cond_set_guest_storage_key);
 713
 714 /**
 715  * Reset a guest reference bit (rrbe), returning the reference and changed bit.
 716  *
 717  * Returns < 0 in case of error, otherwise the cc to be reported to the guest.
 718  */
 719 int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr)
 720 {
 721         spinlock_t *ptl;
 722         pgste_t old, new;
 723         pte_t *ptep;
 724         int cc = 0;
 725
 726         ptep = get_locked_pte(mm, addr, &ptl);
 727         if (unlikely(!ptep))
 728                 return -EFAULT;
 729
 730         new = old = pgste_get_lock(ptep);
 731         /* Reset guest reference bit only */
 732         pgste_val(new) &= ~PGSTE_GR_BIT;
 733
 734         if (!(pte_val(*ptep) & _PAGE_INVALID)) {
 735                 cc = page_reset_referenced(pte_val(*ptep) & PAGE_MASK);
 736                 /* Merge real referenced bit into host-set */
 737                 pgste_val(new) |= ((unsigned long) cc << 53) & PGSTE_HR_BIT;
 738         }
 739         /* Reflect guest's logical view, not physical */
 740         cc |= (pgste_val(old) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 49;
 741         /* Changing the guest storage key is considered a change of the page */
 742         if ((pgste_val(new) ^ pgste_val(old)) & PGSTE_GR_BIT)
 743                 pgste_val(new) |= PGSTE_UC_BIT;
 744
 745         pgste_set_unlock(ptep, new);
 746         pte_unmap_unlock(ptep, ptl);
 747         return cc;
 748 }
 749 EXPORT_SYMBOL(reset_guest_reference_bit);
 750
 751 int get_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 752                           unsigned char *key)
 753 {
 754         spinlock_t *ptl;
 755         pgste_t pgste;
 756         pte_t *ptep;
 757
 758         ptep = get_locked_pte(mm, addr, &ptl);
 759         if (unlikely(!ptep))
 760                 return -EFAULT;
 761
 762         pgste = pgste_get_lock(ptep);
 763         *key = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
 764         if (!(pte_val(*ptep) & _PAGE_INVALID))
 765                 *key = page_get_storage_key(pte_val(*ptep) & PAGE_MASK);
 766         /* Reflect guest's logical view, not physical */
 767         *key |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48;
 768         pgste_set_unlock(ptep, pgste);
 769         pte_unmap_unlock(ptep, ptl);
 770         return 0;
 771 }
 772 EXPORT_SYMBOL(get_guest_storage_key);
 773 #endif