arch/s390/mm/pgtable.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *    Copyright IBM Corp. 2007, 2011
   4  *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
   5  */
   6
   7 #include <linux/sched.h>
   8 #include <linux/kernel.h>
   9 #include <linux/errno.h>
  10 #include <linux/gfp.h>
  11 #include <linux/mm.h>
  12 #include <linux/swap.h>
  13 #include <linux/smp.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/rcupdate.h>
  16 #include <linux/slab.h>
  17 #include <linux/swapops.h>
  18 #include <linux/sysctl.h>
  19 #include <linux/ksm.h>
  20 #include <linux/mman.h>
  21
  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 #include <asm/page-states.h>
  28
  29 static inline void ptep_ipte_local(struct mm_struct *mm, unsigned long addr,
  30                                    pte_t *ptep, int nodat)
  31 {
  32         unsigned long opt, asce;
  33
  34         if (MACHINE_HAS_TLB_GUEST) {
  35                 opt = 0;
  36                 asce = READ_ONCE(mm->context.gmap_asce);
  37                 if (asce == 0UL || nodat)
  38                         opt |= IPTE_NODAT;
  39                 if (asce != -1UL) {
  40                         asce = asce ? : mm->context.asce;
  41                         opt |= IPTE_GUEST_ASCE;
  42                 }
  43                 __ptep_ipte(addr, ptep, opt, asce, IPTE_LOCAL);
  44         } else {
  45                 __ptep_ipte(addr, ptep, 0, 0, IPTE_LOCAL);
  46         }
  47 }
  48
  49 static inline void ptep_ipte_global(struct mm_struct *mm, unsigned long addr,
  50                                     pte_t *ptep, int nodat)
  51 {
  52         unsigned long opt, asce;
  53
  54         if (MACHINE_HAS_TLB_GUEST) {
  55                 opt = 0;
  56                 asce = READ_ONCE(mm->context.gmap_asce);
  57                 if (asce == 0UL || nodat)
  58                         opt |= IPTE_NODAT;
  59                 if (asce != -1UL) {
  60                         asce = asce ? : mm->context.asce;
  61                         opt |= IPTE_GUEST_ASCE;
  62                 }
  63                 __ptep_ipte(addr, ptep, opt, asce, IPTE_GLOBAL);
  64         } else {
  65                 __ptep_ipte(addr, ptep, 0, 0, IPTE_GLOBAL);
  66         }
  67 }
  68
  69 static inline pte_t ptep_flush_direct(struct mm_struct *mm,
  70                                       unsigned long addr, pte_t *ptep,
  71                                       int nodat)
  72 {
  73         pte_t old;
  74
  75         old = *ptep;
  76         if (unlikely(pte_val(old) & _PAGE_INVALID))
  77                 return old;
  78         atomic_inc(&mm->context.flush_count);
  79         if (MACHINE_HAS_TLB_LC &&
  80             cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
  81                 ptep_ipte_local(mm, addr, ptep, nodat);
  82         else
  83                 ptep_ipte_global(mm, addr, ptep, nodat);
  84         atomic_dec(&mm->context.flush_count);
  85         return old;
  86 }
  87
  88 static inline pte_t ptep_flush_lazy(struct mm_struct *mm,
  89                                     unsigned long addr, pte_t *ptep,
  90                                     int nodat)
  91 {
  92         pte_t old;
  93
  94         old = *ptep;
  95         if (unlikely(pte_val(old) & _PAGE_INVALID))
  96                 return old;
  97         atomic_inc(&mm->context.flush_count);
  98         if (cpumask_equal(&mm->context.cpu_attach_mask,
  99                           cpumask_of(smp_processor_id()))) {
 100                 pte_val(*ptep) |= _PAGE_INVALID;
 101                 mm->context.flush_mm = 1;
 102         } else
 103                 ptep_ipte_global(mm, addr, ptep, nodat);
 104         atomic_dec(&mm->context.flush_count);
 105         return old;
 106 }
 107
 108 static inline pgste_t pgste_get_lock(pte_t *ptep)
 109 {
 110         unsigned long new = 0;
 111 #ifdef CONFIG_PGSTE
 112         unsigned long old;
 113
 114         asm(
 115                 "       lg      %0,%2\n"
 116                 "0:     lgr     %1,%0\n"
 117                 "       nihh    %0,0xff7f\n"    /* clear PCL bit in old */
 118                 "       oihh    %1,0x0080\n"    /* set PCL bit in new */
 119                 "       csg     %0,%1,%2\n"
 120                 "       jl      0b\n"
 121                 : "=&d" (old), "=&d" (new), "=Q" (ptep[PTRS_PER_PTE])
 122                 : "Q" (ptep[PTRS_PER_PTE]) : "cc", "memory");
 123 #endif
 124         return __pgste(new);
 125 }
 126
 127 static inline void pgste_set_unlock(pte_t *ptep, pgste_t pgste)
 128 {
 129 #ifdef CONFIG_PGSTE
 130         asm(
 131                 "       nihh    %1,0xff7f\n"    /* clear PCL bit */
 132                 "       stg     %1,%0\n"
 133                 : "=Q" (ptep[PTRS_PER_PTE])
 134                 : "d" (pgste_val(pgste)), "Q" (ptep[PTRS_PER_PTE])
 135                 : "cc", "memory");
 136 #endif
 137 }
 138
 139 static inline pgste_t pgste_get(pte_t *ptep)
 140 {
 141         unsigned long pgste = 0;
 142 #ifdef CONFIG_PGSTE
 143         pgste = *(unsigned long *)(ptep + PTRS_PER_PTE);
 144 #endif
 145         return __pgste(pgste);
 146 }
 147
 148 static inline void pgste_set(pte_t *ptep, pgste_t pgste)
 149 {
 150 #ifdef CONFIG_PGSTE
 151         *(pgste_t *)(ptep + PTRS_PER_PTE) = pgste;
 152 #endif
 153 }
 154
 155 static inline pgste_t pgste_update_all(pte_t pte, pgste_t pgste,
 156                                        struct mm_struct *mm)
 157 {
 158 #ifdef CONFIG_PGSTE
 159         unsigned long address, bits, skey;
 160
 161         if (!mm_use_skey(mm) || pte_val(pte) & _PAGE_INVALID)
 162                 return pgste;
 163         address = pte_val(pte) & PAGE_MASK;
 164         skey = (unsigned long) page_get_storage_key(address);
 165         bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED);
 166         /* Transfer page changed & referenced bit to guest bits in pgste */
 167         pgste_val(pgste) |= bits << 48;         /* GR bit & GC bit */
 168         /* Copy page access key and fetch protection bit to pgste */
 169         pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT);
 170         pgste_val(pgste) |= (skey & (_PAGE_ACC_BITS | _PAGE_FP_BIT)) << 56;
 171 #endif
 172         return pgste;
 173
 174 }
 175
 176 static inline void pgste_set_key(pte_t *ptep, pgste_t pgste, pte_t entry,
 177                                  struct mm_struct *mm)
 178 {
 179 #ifdef CONFIG_PGSTE
 180         unsigned long address;
 181         unsigned long nkey;
 182
 183         if (!mm_use_skey(mm) || pte_val(entry) & _PAGE_INVALID)
 184                 return;
 185         VM_BUG_ON(!(pte_val(*ptep) & _PAGE_INVALID));
 186         address = pte_val(entry) & PAGE_MASK;
 187         /*
 188          * Set page access key and fetch protection bit from pgste.
 189          * The guest C/R information is still in the PGSTE, set real
 190          * key C/R to 0.
 191          */
 192         nkey = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
 193         nkey |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48;
 194         page_set_storage_key(address, nkey, 0);
 195 #endif
 196 }
 197
 198 static inline pgste_t pgste_set_pte(pte_t *ptep, pgste_t pgste, pte_t entry)
 199 {
 200 #ifdef CONFIG_PGSTE
 201         if ((pte_val(entry) & _PAGE_PRESENT) &&
 202             (pte_val(entry) & _PAGE_WRITE) &&
 203             !(pte_val(entry) & _PAGE_INVALID)) {
 204                 if (!MACHINE_HAS_ESOP) {
 205                         /*
 206                          * Without enhanced suppression-on-protection force
 207                          * the dirty bit on for all writable ptes.
 208                          */
 209                         pte_val(entry) |= _PAGE_DIRTY;
 210                         pte_val(entry) &= ~_PAGE_PROTECT;
 211                 }
 212                 if (!(pte_val(entry) & _PAGE_PROTECT))
 213                         /* This pte allows write access, set user-dirty */
 214                         pgste_val(pgste) |= PGSTE_UC_BIT;
 215         }
 216 #endif
 217         *ptep = entry;
 218         return pgste;
 219 }
 220
 221 static inline pgste_t pgste_pte_notify(struct mm_struct *mm,
 222                                        unsigned long addr,
 223                                        pte_t *ptep, pgste_t pgste)
 224 {
 225 #ifdef CONFIG_PGSTE
 226         unsigned long bits;
 227
 228         bits = pgste_val(pgste) & (PGSTE_IN_BIT | PGSTE_VSIE_BIT);
 229         if (bits) {
 230                 pgste_val(pgste) ^= bits;
 231                 ptep_notify(mm, addr, ptep, bits);
 232         }
 233 #endif
 234         return pgste;
 235 }
 236
 237 static inline pgste_t ptep_xchg_start(struct mm_struct *mm,
 238                                       unsigned long addr, pte_t *ptep)
 239 {
 240         pgste_t pgste = __pgste(0);
 241
 242         if (mm_has_pgste(mm)) {
 243                 pgste = pgste_get_lock(ptep);
 244                 pgste = pgste_pte_notify(mm, addr, ptep, pgste);
 245         }
 246         return pgste;
 247 }
 248
 249 static inline pte_t ptep_xchg_commit(struct mm_struct *mm,
 250                                     unsigned long addr, pte_t *ptep,
 251                                     pgste_t pgste, pte_t old, pte_t new)
 252 {
 253         if (mm_has_pgste(mm)) {
 254                 if (pte_val(old) & _PAGE_INVALID)
 255                         pgste_set_key(ptep, pgste, new, mm);
 256                 if (pte_val(new) & _PAGE_INVALID) {
 257                         pgste = pgste_update_all(old, pgste, mm);
 258                         if ((pgste_val(pgste) & _PGSTE_GPS_USAGE_MASK) ==
 259                             _PGSTE_GPS_USAGE_UNUSED)
 260                                 pte_val(old) |= _PAGE_UNUSED;
 261                 }
 262                 pgste = pgste_set_pte(ptep, pgste, new);
 263                 pgste_set_unlock(ptep, pgste);
 264         } else {
 265                 *ptep = new;
 266         }
 267         return old;
 268 }
 269
 270 pte_t ptep_xchg_direct(struct mm_struct *mm, unsigned long addr,
 271                        pte_t *ptep, pte_t new)
 272 {
 273         pgste_t pgste;
 274         pte_t old;
 275         int nodat;
 276
 277         preempt_disable();
 278         pgste = ptep_xchg_start(mm, addr, ptep);
 279         nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 280         old = ptep_flush_direct(mm, addr, ptep, nodat);
 281         old = ptep_xchg_commit(mm, addr, ptep, pgste, old, new);
 282         preempt_enable();
 283         return old;
 284 }
 285 EXPORT_SYMBOL(ptep_xchg_direct);
 286
 287 pte_t ptep_xchg_lazy(struct mm_struct *mm, unsigned long addr,
 288                      pte_t *ptep, pte_t new)
 289 {
 290         pgste_t pgste;
 291         pte_t old;
 292         int nodat;
 293
 294         preempt_disable();
 295         pgste = ptep_xchg_start(mm, addr, ptep);
 296         nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 297         old = ptep_flush_lazy(mm, addr, ptep, nodat);
 298         old = ptep_xchg_commit(mm, addr, ptep, pgste, old, new);
 299         preempt_enable();
 300         return old;
 301 }
 302 EXPORT_SYMBOL(ptep_xchg_lazy);
 303
 304 pte_t ptep_modify_prot_start(struct mm_struct *mm, unsigned long addr,
 305                              pte_t *ptep)
 306 {
 307         pgste_t pgste;
 308         pte_t old;
 309         int nodat;
 310
 311         preempt_disable();
 312         pgste = ptep_xchg_start(mm, addr, ptep);
 313         nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 314         old = ptep_flush_lazy(mm, addr, ptep, nodat);
 315         if (mm_has_pgste(mm)) {
 316                 pgste = pgste_update_all(old, pgste, mm);
 317                 pgste_set(ptep, pgste);
 318         }
 319         return old;
 320 }
 321 EXPORT_SYMBOL(ptep_modify_prot_start);
 322
 323 void ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
 324                              pte_t *ptep, pte_t pte)
 325 {
 326         pgste_t pgste;
 327
 328         if (!MACHINE_HAS_NX)
 329                 pte_val(pte) &= ~_PAGE_NOEXEC;
 330         if (mm_has_pgste(mm)) {
 331                 pgste = pgste_get(ptep);
 332                 pgste_set_key(ptep, pgste, pte, mm);
 333                 pgste = pgste_set_pte(ptep, pgste, pte);
 334                 pgste_set_unlock(ptep, pgste);
 335         } else {
 336                 *ptep = pte;
 337         }
 338         preempt_enable();
 339 }
 340 EXPORT_SYMBOL(ptep_modify_prot_commit);
 341
 342 static inline void pmdp_idte_local(struct mm_struct *mm,
 343                                    unsigned long addr, pmd_t *pmdp)
 344 {
 345         if (MACHINE_HAS_TLB_GUEST)
 346                 __pmdp_idte(addr, pmdp, IDTE_NODAT | IDTE_GUEST_ASCE,
 347                             mm->context.asce, IDTE_LOCAL);
 348         else
 349                 __pmdp_idte(addr, pmdp, 0, 0, IDTE_LOCAL);
 350 }
 351
 352 static inline void pmdp_idte_global(struct mm_struct *mm,
 353                                     unsigned long addr, pmd_t *pmdp)
 354 {
 355         if (MACHINE_HAS_TLB_GUEST)
 356                 __pmdp_idte(addr, pmdp, IDTE_NODAT | IDTE_GUEST_ASCE,
 357                             mm->context.asce, IDTE_GLOBAL);
 358         else if (MACHINE_HAS_IDTE)
 359                 __pmdp_idte(addr, pmdp, 0, 0, IDTE_GLOBAL);
 360         else
 361                 __pmdp_csp(pmdp);
 362 }
 363
 364 static inline pmd_t pmdp_flush_direct(struct mm_struct *mm,
 365                                       unsigned long addr, pmd_t *pmdp)
 366 {
 367         pmd_t old;
 368
 369         old = *pmdp;
 370         if (pmd_val(old) & _SEGMENT_ENTRY_INVALID)
 371                 return old;
 372         atomic_inc(&mm->context.flush_count);
 373         if (MACHINE_HAS_TLB_LC &&
 374             cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
 375                 pmdp_idte_local(mm, addr, pmdp);
 376         else
 377                 pmdp_idte_global(mm, addr, pmdp);
 378         atomic_dec(&mm->context.flush_count);
 379         return old;
 380 }
 381
 382 static inline pmd_t pmdp_flush_lazy(struct mm_struct *mm,
 383                                     unsigned long addr, pmd_t *pmdp)
 384 {
 385         pmd_t old;
 386
 387         old = *pmdp;
 388         if (pmd_val(old) & _SEGMENT_ENTRY_INVALID)
 389                 return old;
 390         atomic_inc(&mm->context.flush_count);
 391         if (cpumask_equal(&mm->context.cpu_attach_mask,
 392                           cpumask_of(smp_processor_id()))) {
 393                 pmd_val(*pmdp) |= _SEGMENT_ENTRY_INVALID;
 394                 mm->context.flush_mm = 1;
 395         } else {
 396                 pmdp_idte_global(mm, addr, pmdp);
 397         }
 398         atomic_dec(&mm->context.flush_count);
 399         return old;
 400 }
 401
 402 pmd_t pmdp_xchg_direct(struct mm_struct *mm, unsigned long addr,
 403                        pmd_t *pmdp, pmd_t new)
 404 {
 405         pmd_t old;
 406
 407         preempt_disable();
 408         old = pmdp_flush_direct(mm, addr, pmdp);
 409         *pmdp = new;
 410         preempt_enable();
 411         return old;
 412 }
 413 EXPORT_SYMBOL(pmdp_xchg_direct);
 414
 415 pmd_t pmdp_xchg_lazy(struct mm_struct *mm, unsigned long addr,
 416                      pmd_t *pmdp, pmd_t new)
 417 {
 418         pmd_t old;
 419
 420         preempt_disable();
 421         old = pmdp_flush_lazy(mm, addr, pmdp);
 422         *pmdp = new;
 423         preempt_enable();
 424         return old;
 425 }
 426 EXPORT_SYMBOL(pmdp_xchg_lazy);
 427
 428 static inline void pudp_idte_local(struct mm_struct *mm,
 429                                    unsigned long addr, pud_t *pudp)
 430 {
 431         if (MACHINE_HAS_TLB_GUEST)
 432                 __pudp_idte(addr, pudp, IDTE_NODAT | IDTE_GUEST_ASCE,
 433                             mm->context.asce, IDTE_LOCAL);
 434         else
 435                 __pudp_idte(addr, pudp, 0, 0, IDTE_LOCAL);
 436 }
 437
 438 static inline void pudp_idte_global(struct mm_struct *mm,
 439                                     unsigned long addr, pud_t *pudp)
 440 {
 441         if (MACHINE_HAS_TLB_GUEST)
 442                 __pudp_idte(addr, pudp, IDTE_NODAT | IDTE_GUEST_ASCE,
 443                             mm->context.asce, IDTE_GLOBAL);
 444         else if (MACHINE_HAS_IDTE)
 445                 __pudp_idte(addr, pudp, 0, 0, IDTE_GLOBAL);
 446         else
 447                 /*
 448                  * Invalid bit position is the same for pmd and pud, so we can
 449                  * re-use _pmd_csp() here
 450                  */
 451                 __pmdp_csp((pmd_t *) pudp);
 452 }
 453
 454 static inline pud_t pudp_flush_direct(struct mm_struct *mm,
 455                                       unsigned long addr, pud_t *pudp)
 456 {
 457         pud_t old;
 458
 459         old = *pudp;
 460         if (pud_val(old) & _REGION_ENTRY_INVALID)
 461                 return old;
 462         atomic_inc(&mm->context.flush_count);
 463         if (MACHINE_HAS_TLB_LC &&
 464             cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
 465                 pudp_idte_local(mm, addr, pudp);
 466         else
 467                 pudp_idte_global(mm, addr, pudp);
 468         atomic_dec(&mm->context.flush_count);
 469         return old;
 470 }
 471
 472 pud_t pudp_xchg_direct(struct mm_struct *mm, unsigned long addr,
 473                        pud_t *pudp, pud_t new)
 474 {
 475         pud_t old;
 476
 477         preempt_disable();
 478         old = pudp_flush_direct(mm, addr, pudp);
 479         *pudp = new;
 480         preempt_enable();
 481         return old;
 482 }
 483 EXPORT_SYMBOL(pudp_xchg_direct);
 484
 485 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 486 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 487                                 pgtable_t pgtable)
 488 {
 489         struct list_head *lh = (struct list_head *) pgtable;
 490
 491         assert_spin_locked(pmd_lockptr(mm, pmdp));
 492
 493         /* FIFO */
 494         if (!pmd_huge_pte(mm, pmdp))
 495                 INIT_LIST_HEAD(lh);
 496         else
 497                 list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
 498         pmd_huge_pte(mm, pmdp) = pgtable;
 499 }
 500
 501 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 502 {
 503         struct list_head *lh;
 504         pgtable_t pgtable;
 505         pte_t *ptep;
 506
 507         assert_spin_locked(pmd_lockptr(mm, pmdp));
 508
 509         /* FIFO */
 510         pgtable = pmd_huge_pte(mm, pmdp);
 511         lh = (struct list_head *) pgtable;
 512         if (list_empty(lh))
 513                 pmd_huge_pte(mm, pmdp) = NULL;
 514         else {
 515                 pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
 516                 list_del(lh);
 517         }
 518         ptep = (pte_t *) pgtable;
 519         pte_val(*ptep) = _PAGE_INVALID;
 520         ptep++;
 521         pte_val(*ptep) = _PAGE_INVALID;
 522         return pgtable;
 523 }
 524 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 525
 526 #ifdef CONFIG_PGSTE
 527 void ptep_set_pte_at(struct mm_struct *mm, unsigned long addr,
 528                      pte_t *ptep, pte_t entry)
 529 {
 530         pgste_t pgste;
 531
 532         /* the mm_has_pgste() check is done in set_pte_at() */
 533         preempt_disable();
 534         pgste = pgste_get_lock(ptep);
 535         pgste_val(pgste) &= ~_PGSTE_GPS_ZERO;
 536         pgste_set_key(ptep, pgste, entry, mm);
 537         pgste = pgste_set_pte(ptep, pgste, entry);
 538         pgste_set_unlock(ptep, pgste);
 539         preempt_enable();
 540 }
 541
 542 void ptep_set_notify(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 543 {
 544         pgste_t pgste;
 545
 546         preempt_disable();
 547         pgste = pgste_get_lock(ptep);
 548         pgste_val(pgste) |= PGSTE_IN_BIT;
 549         pgste_set_unlock(ptep, pgste);
 550         preempt_enable();
 551 }
 552
 553 /**
 554  * ptep_force_prot - change access rights of a locked pte
 555  * @mm: pointer to the process mm_struct
 556  * @addr: virtual address in the guest address space
 557  * @ptep: pointer to the page table entry
 558  * @prot: indicates guest access rights: PROT_NONE, PROT_READ or PROT_WRITE
 559  * @bit: pgste bit to set (e.g. for notification)
 560  *
 561  * Returns 0 if the access rights were changed and -EAGAIN if the current
 562  * and requested access rights are incompatible.
 563  */
 564 int ptep_force_prot(struct mm_struct *mm, unsigned long addr,
 565                     pte_t *ptep, int prot, unsigned long bit)
 566 {
 567         pte_t entry;
 568         pgste_t pgste;
 569         int pte_i, pte_p, nodat;
 570
 571         pgste = pgste_get_lock(ptep);
 572         entry = *ptep;
 573         /* Check pte entry after all locks have been acquired */
 574         pte_i = pte_val(entry) & _PAGE_INVALID;
 575         pte_p = pte_val(entry) & _PAGE_PROTECT;
 576         if ((pte_i && (prot != PROT_NONE)) ||
 577             (pte_p && (prot & PROT_WRITE))) {
 578                 pgste_set_unlock(ptep, pgste);
 579                 return -EAGAIN;
 580         }
 581         /* Change access rights and set pgste bit */
 582         nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 583         if (prot == PROT_NONE && !pte_i) {
 584                 ptep_flush_direct(mm, addr, ptep, nodat);
 585                 pgste = pgste_update_all(entry, pgste, mm);
 586                 pte_val(entry) |= _PAGE_INVALID;
 587         }
 588         if (prot == PROT_READ && !pte_p) {
 589                 ptep_flush_direct(mm, addr, ptep, nodat);
 590                 pte_val(entry) &= ~_PAGE_INVALID;
 591                 pte_val(entry) |= _PAGE_PROTECT;
 592         }
 593         pgste_val(pgste) |= bit;
 594         pgste = pgste_set_pte(ptep, pgste, entry);
 595         pgste_set_unlock(ptep, pgste);
 596         return 0;
 597 }
 598
 599 int ptep_shadow_pte(struct mm_struct *mm, unsigned long saddr,
 600                     pte_t *sptep, pte_t *tptep, pte_t pte)
 601 {
 602         pgste_t spgste, tpgste;
 603         pte_t spte, tpte;
 604         int rc = -EAGAIN;
 605
 606         if (!(pte_val(*tptep) & _PAGE_INVALID))
 607                 return 0;       /* already shadowed */
 608         spgste = pgste_get_lock(sptep);
 609         spte = *sptep;
 610         if (!(pte_val(spte) & _PAGE_INVALID) &&
 611             !((pte_val(spte) & _PAGE_PROTECT) &&
 612               !(pte_val(pte) & _PAGE_PROTECT))) {
 613                 pgste_val(spgste) |= PGSTE_VSIE_BIT;
 614                 tpgste = pgste_get_lock(tptep);
 615                 pte_val(tpte) = (pte_val(spte) & PAGE_MASK) |
 616                                 (pte_val(pte) & _PAGE_PROTECT);
 617                 /* don't touch the storage key - it belongs to parent pgste */
 618                 tpgste = pgste_set_pte(tptep, tpgste, tpte);
 619                 pgste_set_unlock(tptep, tpgste);
 620                 rc = 1;
 621         }
 622         pgste_set_unlock(sptep, spgste);
 623         return rc;
 624 }
 625
 626 void ptep_unshadow_pte(struct mm_struct *mm, unsigned long saddr, pte_t *ptep)
 627 {
 628         pgste_t pgste;
 629         int nodat;
 630
 631         pgste = pgste_get_lock(ptep);
 632         /* notifier is called by the caller */
 633         nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 634         ptep_flush_direct(mm, saddr, ptep, nodat);
 635         /* don't touch the storage key - it belongs to parent pgste */
 636         pgste = pgste_set_pte(ptep, pgste, __pte(_PAGE_INVALID));
 637         pgste_set_unlock(ptep, pgste);
 638 }
 639
 640 static void ptep_zap_swap_entry(struct mm_struct *mm, swp_entry_t entry)
 641 {
 642         if (!non_swap_entry(entry))
 643                 dec_mm_counter(mm, MM_SWAPENTS);
 644         else if (is_migration_entry(entry)) {
 645                 struct page *page = migration_entry_to_page(entry);
 646
 647                 dec_mm_counter(mm, mm_counter(page));
 648         }
 649         free_swap_and_cache(entry);
 650 }
 651
 652 void ptep_zap_unused(struct mm_struct *mm, unsigned long addr,
 653                      pte_t *ptep, int reset)
 654 {
 655         unsigned long pgstev;
 656         pgste_t pgste;
 657         pte_t pte;
 658
 659         /* Zap unused and logically-zero pages */
 660         preempt_disable();
 661         pgste = pgste_get_lock(ptep);
 662         pgstev = pgste_val(pgste);
 663         pte = *ptep;
 664         if (!reset && pte_swap(pte) &&
 665             ((pgstev & _PGSTE_GPS_USAGE_MASK) == _PGSTE_GPS_USAGE_UNUSED ||
 666              (pgstev & _PGSTE_GPS_ZERO))) {
 667                 ptep_zap_swap_entry(mm, pte_to_swp_entry(pte));
 668                 pte_clear(mm, addr, ptep);
 669         }
 670         if (reset)
 671                 pgste_val(pgste) &= ~_PGSTE_GPS_USAGE_MASK;
 672         pgste_set_unlock(ptep, pgste);
 673         preempt_enable();
 674 }
 675
 676 void ptep_zap_key(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 677 {
 678         unsigned long ptev;
 679         pgste_t pgste;
 680
 681         /* Clear storage key ACC and F, but set R/C */
 682         preempt_disable();
 683         pgste = pgste_get_lock(ptep);
 684         pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT);
 685         pgste_val(pgste) |= PGSTE_GR_BIT | PGSTE_GC_BIT;
 686         ptev = pte_val(*ptep);
 687         if (!(ptev & _PAGE_INVALID) && (ptev & _PAGE_WRITE))
 688                 page_set_storage_key(ptev & PAGE_MASK, PAGE_DEFAULT_KEY, 1);
 689         pgste_set_unlock(ptep, pgste);
 690         preempt_enable();
 691 }
 692
 693 /*
 694  * Test and reset if a guest page is dirty
 695  */
 696 bool test_and_clear_guest_dirty(struct mm_struct *mm, unsigned long addr)
 697 {
 698         spinlock_t *ptl;
 699         pgd_t *pgd;
 700         p4d_t *p4d;
 701         pud_t *pud;
 702         pmd_t *pmd;
 703         pgste_t pgste;
 704         pte_t *ptep;
 705         pte_t pte;
 706         bool dirty;
 707         int nodat;
 708
 709         pgd = pgd_offset(mm, addr);
 710         p4d = p4d_alloc(mm, pgd, addr);
 711         if (!p4d)
 712                 return false;
 713         pud = pud_alloc(mm, p4d, addr);
 714         if (!pud)
 715                 return false;
 716         pmd = pmd_alloc(mm, pud, addr);
 717         if (!pmd)
 718                 return false;
 719         /* We can't run guests backed by huge pages, but userspace can
 720          * still set them up and then try to migrate them without any
 721          * migration support.
 722          */
 723         if (pmd_large(*pmd))
 724                 return true;
 725
 726         ptep = pte_alloc_map_lock(mm, pmd, addr, &ptl);
 727         if (unlikely(!ptep))
 728                 return false;
 729
 730         pgste = pgste_get_lock(ptep);
 731         dirty = !!(pgste_val(pgste) & PGSTE_UC_BIT);
 732         pgste_val(pgste) &= ~PGSTE_UC_BIT;
 733         pte = *ptep;
 734         if (dirty && (pte_val(pte) & _PAGE_PRESENT)) {
 735                 pgste = pgste_pte_notify(mm, addr, ptep, pgste);
 736                 nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 737                 ptep_ipte_global(mm, addr, ptep, nodat);
 738                 if (MACHINE_HAS_ESOP || !(pte_val(pte) & _PAGE_WRITE))
 739                         pte_val(pte) |= _PAGE_PROTECT;
 740                 else
 741                         pte_val(pte) |= _PAGE_INVALID;
 742                 *ptep = pte;
 743         }
 744         pgste_set_unlock(ptep, pgste);
 745
 746         spin_unlock(ptl);
 747         return dirty;
 748 }
 749 EXPORT_SYMBOL_GPL(test_and_clear_guest_dirty);
 750
 751 int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 752                           unsigned char key, bool nq)
 753 {
 754         unsigned long keyul;
 755         spinlock_t *ptl;
 756         pgste_t old, new;
 757         pte_t *ptep;
 758
 759         ptep = get_locked_pte(mm, addr, &ptl);
 760         if (unlikely(!ptep))
 761                 return -EFAULT;
 762
 763         new = old = pgste_get_lock(ptep);
 764         pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT |
 765                             PGSTE_ACC_BITS | PGSTE_FP_BIT);
 766         keyul = (unsigned long) key;
 767         pgste_val(new) |= (keyul & (_PAGE_CHANGED | _PAGE_REFERENCED)) << 48;
 768         pgste_val(new) |= (keyul & (_PAGE_ACC_BITS | _PAGE_FP_BIT)) << 56;
 769         if (!(pte_val(*ptep) & _PAGE_INVALID)) {
 770                 unsigned long address, bits, skey;
 771
 772                 address = pte_val(*ptep) & PAGE_MASK;
 773                 skey = (unsigned long) page_get_storage_key(address);
 774                 bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED);
 775                 skey = key & (_PAGE_ACC_BITS | _PAGE_FP_BIT);
 776                 /* Set storage key ACC and FP */
 777                 page_set_storage_key(address, skey, !nq);
 778                 /* Merge host changed & referenced into pgste  */
 779                 pgste_val(new) |= bits << 52;
 780         }
 781         /* changing the guest storage key is considered a change of the page */
 782         if ((pgste_val(new) ^ pgste_val(old)) &
 783             (PGSTE_ACC_BITS | PGSTE_FP_BIT | PGSTE_GR_BIT | PGSTE_GC_BIT))
 784                 pgste_val(new) |= PGSTE_UC_BIT;
 785
 786         pgste_set_unlock(ptep, new);
 787         pte_unmap_unlock(ptep, ptl);
 788         return 0;
 789 }
 790 EXPORT_SYMBOL(set_guest_storage_key);
 791
 792 /**
 793  * Conditionally set a guest storage key (handling csske).
 794  * oldkey will be updated when either mr or mc is set and a pointer is given.
 795  *
 796  * Returns 0 if a guests storage key update wasn't necessary, 1 if the guest
 797  * storage key was updated and -EFAULT on access errors.
 798  */
 799 int cond_set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 800                                unsigned char key, unsigned char *oldkey,
 801                                bool nq, bool mr, bool mc)
 802 {
 803         unsigned char tmp, mask = _PAGE_ACC_BITS | _PAGE_FP_BIT;
 804         int rc;
 805
 806         /* we can drop the pgste lock between getting and setting the key */
 807         if (mr | mc) {
 808                 rc = get_guest_storage_key(current->mm, addr, &tmp);
 809                 if (rc)
 810                         return rc;
 811                 if (oldkey)
 812                         *oldkey = tmp;
 813                 if (!mr)
 814                         mask |= _PAGE_REFERENCED;
 815                 if (!mc)
 816                         mask |= _PAGE_CHANGED;
 817                 if (!((tmp ^ key) & mask))
 818                         return 0;
 819         }
 820         rc = set_guest_storage_key(current->mm, addr, key, nq);
 821         return rc < 0 ? rc : 1;
 822 }
 823 EXPORT_SYMBOL(cond_set_guest_storage_key);
 824
 825 /**
 826  * Reset a guest reference bit (rrbe), returning the reference and changed bit.
 827  *
 828  * Returns < 0 in case of error, otherwise the cc to be reported to the guest.
 829  */
 830 int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr)
 831 {
 832         spinlock_t *ptl;
 833         pgste_t old, new;
 834         pte_t *ptep;
 835         int cc = 0;
 836
 837         ptep = get_locked_pte(mm, addr, &ptl);
 838         if (unlikely(!ptep))
 839                 return -EFAULT;
 840
 841         new = old = pgste_get_lock(ptep);
 842         /* Reset guest reference bit only */
 843         pgste_val(new) &= ~PGSTE_GR_BIT;
 844
 845         if (!(pte_val(*ptep) & _PAGE_INVALID)) {
 846                 cc = page_reset_referenced(pte_val(*ptep) & PAGE_MASK);
 847                 /* Merge real referenced bit into host-set */
 848                 pgste_val(new) |= ((unsigned long) cc << 53) & PGSTE_HR_BIT;
 849         }
 850         /* Reflect guest's logical view, not physical */
 851         cc |= (pgste_val(old) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 49;
 852         /* Changing the guest storage key is considered a change of the page */
 853         if ((pgste_val(new) ^ pgste_val(old)) & PGSTE_GR_BIT)
 854                 pgste_val(new) |= PGSTE_UC_BIT;
 855
 856         pgste_set_unlock(ptep, new);
 857         pte_unmap_unlock(ptep, ptl);
 858         return cc;
 859 }
 860 EXPORT_SYMBOL(reset_guest_reference_bit);
 861
 862 int get_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 863                           unsigned char *key)
 864 {
 865         spinlock_t *ptl;
 866         pgste_t pgste;
 867         pte_t *ptep;
 868
 869         ptep = get_locked_pte(mm, addr, &ptl);
 870         if (unlikely(!ptep))
 871                 return -EFAULT;
 872
 873         pgste = pgste_get_lock(ptep);
 874         *key = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
 875         if (!(pte_val(*ptep) & _PAGE_INVALID))
 876                 *key = page_get_storage_key(pte_val(*ptep) & PAGE_MASK);
 877         /* Reflect guest's logical view, not physical */
 878         *key |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48;
 879         pgste_set_unlock(ptep, pgste);
 880         pte_unmap_unlock(ptep, ptl);
 881         return 0;
 882 }
 883 EXPORT_SYMBOL(get_guest_storage_key);
 884
 885 /**
 886  * pgste_perform_essa - perform ESSA actions on the PGSTE.
 887  * @mm: the memory context. It must have PGSTEs, no check is performed here!
 888  * @hva: the host virtual address of the page whose PGSTE is to be processed
 889  * @orc: the specific action to perform, see the ESSA_SET_* macros.
 890  * @oldpte: the PTE will be saved there if the pointer is not NULL.
 891  * @oldpgste: the old PGSTE will be saved there if the pointer is not NULL.
 892  *
 893  * Return: 1 if the page is to be added to the CBRL, otherwise 0,
 894  *         or < 0 in case of error. -EINVAL is returned for invalid values
 895  *         of orc, -EFAULT for invalid addresses.
 896  */
 897 int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc,
 898                         unsigned long *oldpte, unsigned long *oldpgste)
 899 {
 900         unsigned long pgstev;
 901         spinlock_t *ptl;
 902         pgste_t pgste;
 903         pte_t *ptep;
 904         int res = 0;
 905
 906         WARN_ON_ONCE(orc > ESSA_MAX);
 907         if (unlikely(orc > ESSA_MAX))
 908                 return -EINVAL;
 909         ptep = get_locked_pte(mm, hva, &ptl);
 910         if (unlikely(!ptep))
 911                 return -EFAULT;
 912         pgste = pgste_get_lock(ptep);
 913         pgstev = pgste_val(pgste);
 914         if (oldpte)
 915                 *oldpte = pte_val(*ptep);
 916         if (oldpgste)
 917                 *oldpgste = pgstev;
 918
 919         switch (orc) {
 920         case ESSA_GET_STATE:
 921                 break;
 922         case ESSA_SET_STABLE:
 923                 pgstev &= ~(_PGSTE_GPS_USAGE_MASK | _PGSTE_GPS_NODAT);
 924                 pgstev |= _PGSTE_GPS_USAGE_STABLE;
 925                 break;
 926         case ESSA_SET_UNUSED:
 927                 pgstev &= ~_PGSTE_GPS_USAGE_MASK;
 928                 pgstev |= _PGSTE_GPS_USAGE_UNUSED;
 929                 if (pte_val(*ptep) & _PAGE_INVALID)
 930                         res = 1;
 931                 break;
 932         case ESSA_SET_VOLATILE:
 933                 pgstev &= ~_PGSTE_GPS_USAGE_MASK;
 934                 pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
 935                 if (pte_val(*ptep) & _PAGE_INVALID)
 936                         res = 1;
 937                 break;
 938         case ESSA_SET_POT_VOLATILE:
 939                 pgstev &= ~_PGSTE_GPS_USAGE_MASK;
 940                 if (!(pte_val(*ptep) & _PAGE_INVALID)) {
 941                         pgstev |= _PGSTE_GPS_USAGE_POT_VOLATILE;
 942                         break;
 943                 }
 944                 if (pgstev & _PGSTE_GPS_ZERO) {
 945                         pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
 946                         break;
 947                 }
 948                 if (!(pgstev & PGSTE_GC_BIT)) {
 949                         pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
 950                         res = 1;
 951                         break;
 952                 }
 953                 break;
 954         case ESSA_SET_STABLE_RESIDENT:
 955                 pgstev &= ~_PGSTE_GPS_USAGE_MASK;
 956                 pgstev |= _PGSTE_GPS_USAGE_STABLE;
 957                 /*
 958                  * Since the resident state can go away any time after this
 959                  * call, we will not make this page resident. We can revisit
 960                  * this decision if a guest will ever start using this.
 961                  */
 962                 break;
 963         case ESSA_SET_STABLE_IF_RESIDENT:
 964                 if (!(pte_val(*ptep) & _PAGE_INVALID)) {
 965                         pgstev &= ~_PGSTE_GPS_USAGE_MASK;
 966                         pgstev |= _PGSTE_GPS_USAGE_STABLE;
 967                 }
 968                 break;
 969         case ESSA_SET_STABLE_NODAT:
 970                 pgstev &= ~_PGSTE_GPS_USAGE_MASK;
 971                 pgstev |= _PGSTE_GPS_USAGE_STABLE | _PGSTE_GPS_NODAT;
 972                 break;
 973         default:
 974                 /* we should never get here! */
 975                 break;
 976         }
 977         /* If we are discarding a page, set it to logical zero */
 978         if (res)
 979                 pgstev |= _PGSTE_GPS_ZERO;
 980
 981         pgste_val(pgste) = pgstev;
 982         pgste_set_unlock(ptep, pgste);
 983         pte_unmap_unlock(ptep, ptl);
 984         return res;
 985 }
 986 EXPORT_SYMBOL(pgste_perform_essa);
 987
 988 /**
 989  * set_pgste_bits - set specific PGSTE bits.
 990  * @mm: the memory context. It must have PGSTEs, no check is performed here!
 991  * @hva: the host virtual address of the page whose PGSTE is to be processed
 992  * @bits: a bitmask representing the bits that will be touched
 993  * @value: the values of the bits to be written. Only the bits in the mask
 994  *         will be written.
 995  *
 996  * Return: 0 on success, < 0 in case of error.
 997  */
 998 int set_pgste_bits(struct mm_struct *mm, unsigned long hva,
 999                         unsigned long bits, unsigned long value)
1000 {
1001         spinlock_t *ptl;
1002         pgste_t new;
1003         pte_t *ptep;
1004
1005         ptep = get_locked_pte(mm, hva, &ptl);
1006         if (unlikely(!ptep))
1007                 return -EFAULT;
1008         new = pgste_get_lock(ptep);
1009
1010         pgste_val(new) &= ~bits;
1011         pgste_val(new) |= value & bits;
1012
1013         pgste_set_unlock(ptep, new);
1014         pte_unmap_unlock(ptep, ptl);
1015         return 0;
1016 }
1017 EXPORT_SYMBOL(set_pgste_bits);
1018
1019 /**
1020  * get_pgste - get the current PGSTE for the given address.
1021  * @mm: the memory context. It must have PGSTEs, no check is performed here!
1022  * @hva: the host virtual address of the page whose PGSTE is to be processed
1023  * @pgstep: will be written with the current PGSTE for the given address.
1024  *
1025  * Return: 0 on success, < 0 in case of error.
1026  */
1027 int get_pgste(struct mm_struct *mm, unsigned long hva, unsigned long *pgstep)
1028 {
1029         spinlock_t *ptl;
1030         pte_t *ptep;
1031
1032         ptep = get_locked_pte(mm, hva, &ptl);
1033         if (unlikely(!ptep))
1034                 return -EFAULT;
1035         *pgstep = pgste_val(pgste_get(ptep));
1036         pte_unmap_unlock(ptep, ptl);
1037         return 0;
1038 }
1039 EXPORT_SYMBOL(get_pgste);
1040 #endif