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_uses_skeys(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_uses_skeys(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         if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)
 351                 gmap_pmdp_idte_local(mm, addr);
 352 }
 353
 354 static inline void pmdp_idte_global(struct mm_struct *mm,
 355                                     unsigned long addr, pmd_t *pmdp)
 356 {
 357         if (MACHINE_HAS_TLB_GUEST) {
 358                 __pmdp_idte(addr, pmdp, IDTE_NODAT | IDTE_GUEST_ASCE,
 359                             mm->context.asce, IDTE_GLOBAL);
 360                 if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)
 361                         gmap_pmdp_idte_global(mm, addr);
 362         } else if (MACHINE_HAS_IDTE) {
 363                 __pmdp_idte(addr, pmdp, 0, 0, IDTE_GLOBAL);
 364                 if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)
 365                         gmap_pmdp_idte_global(mm, addr);
 366         } else {
 367                 __pmdp_csp(pmdp);
 368                 if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)
 369                         gmap_pmdp_csp(mm, addr);
 370         }
 371 }
 372
 373 static inline pmd_t pmdp_flush_direct(struct mm_struct *mm,
 374                                       unsigned long addr, pmd_t *pmdp)
 375 {
 376         pmd_t old;
 377
 378         old = *pmdp;
 379         if (pmd_val(old) & _SEGMENT_ENTRY_INVALID)
 380                 return old;
 381         atomic_inc(&mm->context.flush_count);
 382         if (MACHINE_HAS_TLB_LC &&
 383             cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
 384                 pmdp_idte_local(mm, addr, pmdp);
 385         else
 386                 pmdp_idte_global(mm, addr, pmdp);
 387         atomic_dec(&mm->context.flush_count);
 388         return old;
 389 }
 390
 391 static inline pmd_t pmdp_flush_lazy(struct mm_struct *mm,
 392                                     unsigned long addr, pmd_t *pmdp)
 393 {
 394         pmd_t old;
 395
 396         old = *pmdp;
 397         if (pmd_val(old) & _SEGMENT_ENTRY_INVALID)
 398                 return old;
 399         atomic_inc(&mm->context.flush_count);
 400         if (cpumask_equal(&mm->context.cpu_attach_mask,
 401                           cpumask_of(smp_processor_id()))) {
 402                 pmd_val(*pmdp) |= _SEGMENT_ENTRY_INVALID;
 403                 mm->context.flush_mm = 1;
 404                 if (mm_has_pgste(mm))
 405                         gmap_pmdp_invalidate(mm, addr);
 406         } else {
 407                 pmdp_idte_global(mm, addr, pmdp);
 408         }
 409         atomic_dec(&mm->context.flush_count);
 410         return old;
 411 }
 412
 413 static pmd_t *pmd_alloc_map(struct mm_struct *mm, unsigned long addr)
 414 {
 415         pgd_t *pgd;
 416         p4d_t *p4d;
 417         pud_t *pud;
 418         pmd_t *pmd;
 419
 420         pgd = pgd_offset(mm, addr);
 421         p4d = p4d_alloc(mm, pgd, addr);
 422         if (!p4d)
 423                 return NULL;
 424         pud = pud_alloc(mm, p4d, addr);
 425         if (!pud)
 426                 return NULL;
 427         pmd = pmd_alloc(mm, pud, addr);
 428         return pmd;
 429 }
 430
 431 pmd_t pmdp_xchg_direct(struct mm_struct *mm, unsigned long addr,
 432                        pmd_t *pmdp, pmd_t new)
 433 {
 434         pmd_t old;
 435
 436         preempt_disable();
 437         old = pmdp_flush_direct(mm, addr, pmdp);
 438         *pmdp = new;
 439         preempt_enable();
 440         return old;
 441 }
 442 EXPORT_SYMBOL(pmdp_xchg_direct);
 443
 444 pmd_t pmdp_xchg_lazy(struct mm_struct *mm, unsigned long addr,
 445                      pmd_t *pmdp, pmd_t new)
 446 {
 447         pmd_t old;
 448
 449         preempt_disable();
 450         old = pmdp_flush_lazy(mm, addr, pmdp);
 451         *pmdp = new;
 452         preempt_enable();
 453         return old;
 454 }
 455 EXPORT_SYMBOL(pmdp_xchg_lazy);
 456
 457 static inline void pudp_idte_local(struct mm_struct *mm,
 458                                    unsigned long addr, pud_t *pudp)
 459 {
 460         if (MACHINE_HAS_TLB_GUEST)
 461                 __pudp_idte(addr, pudp, IDTE_NODAT | IDTE_GUEST_ASCE,
 462                             mm->context.asce, IDTE_LOCAL);
 463         else
 464                 __pudp_idte(addr, pudp, 0, 0, IDTE_LOCAL);
 465 }
 466
 467 static inline void pudp_idte_global(struct mm_struct *mm,
 468                                     unsigned long addr, pud_t *pudp)
 469 {
 470         if (MACHINE_HAS_TLB_GUEST)
 471                 __pudp_idte(addr, pudp, IDTE_NODAT | IDTE_GUEST_ASCE,
 472                             mm->context.asce, IDTE_GLOBAL);
 473         else if (MACHINE_HAS_IDTE)
 474                 __pudp_idte(addr, pudp, 0, 0, IDTE_GLOBAL);
 475         else
 476                 /*
 477                  * Invalid bit position is the same for pmd and pud, so we can
 478                  * re-use _pmd_csp() here
 479                  */
 480                 __pmdp_csp((pmd_t *) pudp);
 481 }
 482
 483 static inline pud_t pudp_flush_direct(struct mm_struct *mm,
 484                                       unsigned long addr, pud_t *pudp)
 485 {
 486         pud_t old;
 487
 488         old = *pudp;
 489         if (pud_val(old) & _REGION_ENTRY_INVALID)
 490                 return old;
 491         atomic_inc(&mm->context.flush_count);
 492         if (MACHINE_HAS_TLB_LC &&
 493             cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
 494                 pudp_idte_local(mm, addr, pudp);
 495         else
 496                 pudp_idte_global(mm, addr, pudp);
 497         atomic_dec(&mm->context.flush_count);
 498         return old;
 499 }
 500
 501 pud_t pudp_xchg_direct(struct mm_struct *mm, unsigned long addr,
 502                        pud_t *pudp, pud_t new)
 503 {
 504         pud_t old;
 505
 506         preempt_disable();
 507         old = pudp_flush_direct(mm, addr, pudp);
 508         *pudp = new;
 509         preempt_enable();
 510         return old;
 511 }
 512 EXPORT_SYMBOL(pudp_xchg_direct);
 513
 514 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 515 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 516                                 pgtable_t pgtable)
 517 {
 518         struct list_head *lh = (struct list_head *) pgtable;
 519
 520         assert_spin_locked(pmd_lockptr(mm, pmdp));
 521
 522         /* FIFO */
 523         if (!pmd_huge_pte(mm, pmdp))
 524                 INIT_LIST_HEAD(lh);
 525         else
 526                 list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
 527         pmd_huge_pte(mm, pmdp) = pgtable;
 528 }
 529
 530 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 531 {
 532         struct list_head *lh;
 533         pgtable_t pgtable;
 534         pte_t *ptep;
 535
 536         assert_spin_locked(pmd_lockptr(mm, pmdp));
 537
 538         /* FIFO */
 539         pgtable = pmd_huge_pte(mm, pmdp);
 540         lh = (struct list_head *) pgtable;
 541         if (list_empty(lh))
 542                 pmd_huge_pte(mm, pmdp) = NULL;
 543         else {
 544                 pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
 545                 list_del(lh);
 546         }
 547         ptep = (pte_t *) pgtable;
 548         pte_val(*ptep) = _PAGE_INVALID;
 549         ptep++;
 550         pte_val(*ptep) = _PAGE_INVALID;
 551         return pgtable;
 552 }
 553 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 554
 555 #ifdef CONFIG_PGSTE
 556 void ptep_set_pte_at(struct mm_struct *mm, unsigned long addr,
 557                      pte_t *ptep, pte_t entry)
 558 {
 559         pgste_t pgste;
 560
 561         /* the mm_has_pgste() check is done in set_pte_at() */
 562         preempt_disable();
 563         pgste = pgste_get_lock(ptep);
 564         pgste_val(pgste) &= ~_PGSTE_GPS_ZERO;
 565         pgste_set_key(ptep, pgste, entry, mm);
 566         pgste = pgste_set_pte(ptep, pgste, entry);
 567         pgste_set_unlock(ptep, pgste);
 568         preempt_enable();
 569 }
 570
 571 void ptep_set_notify(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 572 {
 573         pgste_t pgste;
 574
 575         preempt_disable();
 576         pgste = pgste_get_lock(ptep);
 577         pgste_val(pgste) |= PGSTE_IN_BIT;
 578         pgste_set_unlock(ptep, pgste);
 579         preempt_enable();
 580 }
 581
 582 /**
 583  * ptep_force_prot - change access rights of a locked pte
 584  * @mm: pointer to the process mm_struct
 585  * @addr: virtual address in the guest address space
 586  * @ptep: pointer to the page table entry
 587  * @prot: indicates guest access rights: PROT_NONE, PROT_READ or PROT_WRITE
 588  * @bit: pgste bit to set (e.g. for notification)
 589  *
 590  * Returns 0 if the access rights were changed and -EAGAIN if the current
 591  * and requested access rights are incompatible.
 592  */
 593 int ptep_force_prot(struct mm_struct *mm, unsigned long addr,
 594                     pte_t *ptep, int prot, unsigned long bit)
 595 {
 596         pte_t entry;
 597         pgste_t pgste;
 598         int pte_i, pte_p, nodat;
 599
 600         pgste = pgste_get_lock(ptep);
 601         entry = *ptep;
 602         /* Check pte entry after all locks have been acquired */
 603         pte_i = pte_val(entry) & _PAGE_INVALID;
 604         pte_p = pte_val(entry) & _PAGE_PROTECT;
 605         if ((pte_i && (prot != PROT_NONE)) ||
 606             (pte_p && (prot & PROT_WRITE))) {
 607                 pgste_set_unlock(ptep, pgste);
 608                 return -EAGAIN;
 609         }
 610         /* Change access rights and set pgste bit */
 611         nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 612         if (prot == PROT_NONE && !pte_i) {
 613                 ptep_flush_direct(mm, addr, ptep, nodat);
 614                 pgste = pgste_update_all(entry, pgste, mm);
 615                 pte_val(entry) |= _PAGE_INVALID;
 616         }
 617         if (prot == PROT_READ && !pte_p) {
 618                 ptep_flush_direct(mm, addr, ptep, nodat);
 619                 pte_val(entry) &= ~_PAGE_INVALID;
 620                 pte_val(entry) |= _PAGE_PROTECT;
 621         }
 622         pgste_val(pgste) |= bit;
 623         pgste = pgste_set_pte(ptep, pgste, entry);
 624         pgste_set_unlock(ptep, pgste);
 625         return 0;
 626 }
 627
 628 int ptep_shadow_pte(struct mm_struct *mm, unsigned long saddr,
 629                     pte_t *sptep, pte_t *tptep, pte_t pte)
 630 {
 631         pgste_t spgste, tpgste;
 632         pte_t spte, tpte;
 633         int rc = -EAGAIN;
 634
 635         if (!(pte_val(*tptep) & _PAGE_INVALID))
 636                 return 0;       /* already shadowed */
 637         spgste = pgste_get_lock(sptep);
 638         spte = *sptep;
 639         if (!(pte_val(spte) & _PAGE_INVALID) &&
 640             !((pte_val(spte) & _PAGE_PROTECT) &&
 641               !(pte_val(pte) & _PAGE_PROTECT))) {
 642                 pgste_val(spgste) |= PGSTE_VSIE_BIT;
 643                 tpgste = pgste_get_lock(tptep);
 644                 pte_val(tpte) = (pte_val(spte) & PAGE_MASK) |
 645                                 (pte_val(pte) & _PAGE_PROTECT);
 646                 /* don't touch the storage key - it belongs to parent pgste */
 647                 tpgste = pgste_set_pte(tptep, tpgste, tpte);
 648                 pgste_set_unlock(tptep, tpgste);
 649                 rc = 1;
 650         }
 651         pgste_set_unlock(sptep, spgste);
 652         return rc;
 653 }
 654
 655 void ptep_unshadow_pte(struct mm_struct *mm, unsigned long saddr, pte_t *ptep)
 656 {
 657         pgste_t pgste;
 658         int nodat;
 659
 660         pgste = pgste_get_lock(ptep);
 661         /* notifier is called by the caller */
 662         nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 663         ptep_flush_direct(mm, saddr, ptep, nodat);
 664         /* don't touch the storage key - it belongs to parent pgste */
 665         pgste = pgste_set_pte(ptep, pgste, __pte(_PAGE_INVALID));
 666         pgste_set_unlock(ptep, pgste);
 667 }
 668
 669 static void ptep_zap_swap_entry(struct mm_struct *mm, swp_entry_t entry)
 670 {
 671         if (!non_swap_entry(entry))
 672                 dec_mm_counter(mm, MM_SWAPENTS);
 673         else if (is_migration_entry(entry)) {
 674                 struct page *page = migration_entry_to_page(entry);
 675
 676                 dec_mm_counter(mm, mm_counter(page));
 677         }
 678         free_swap_and_cache(entry);
 679 }
 680
 681 void ptep_zap_unused(struct mm_struct *mm, unsigned long addr,
 682                      pte_t *ptep, int reset)
 683 {
 684         unsigned long pgstev;
 685         pgste_t pgste;
 686         pte_t pte;
 687
 688         /* Zap unused and logically-zero pages */
 689         preempt_disable();
 690         pgste = pgste_get_lock(ptep);
 691         pgstev = pgste_val(pgste);
 692         pte = *ptep;
 693         if (!reset && pte_swap(pte) &&
 694             ((pgstev & _PGSTE_GPS_USAGE_MASK) == _PGSTE_GPS_USAGE_UNUSED ||
 695              (pgstev & _PGSTE_GPS_ZERO))) {
 696                 ptep_zap_swap_entry(mm, pte_to_swp_entry(pte));
 697                 pte_clear(mm, addr, ptep);
 698         }
 699         if (reset)
 700                 pgste_val(pgste) &= ~_PGSTE_GPS_USAGE_MASK;
 701         pgste_set_unlock(ptep, pgste);
 702         preempt_enable();
 703 }
 704
 705 void ptep_zap_key(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 706 {
 707         unsigned long ptev;
 708         pgste_t pgste;
 709
 710         /* Clear storage key ACC and F, but set R/C */
 711         preempt_disable();
 712         pgste = pgste_get_lock(ptep);
 713         pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT);
 714         pgste_val(pgste) |= PGSTE_GR_BIT | PGSTE_GC_BIT;
 715         ptev = pte_val(*ptep);
 716         if (!(ptev & _PAGE_INVALID) && (ptev & _PAGE_WRITE))
 717                 page_set_storage_key(ptev & PAGE_MASK, PAGE_DEFAULT_KEY, 1);
 718         pgste_set_unlock(ptep, pgste);
 719         preempt_enable();
 720 }
 721
 722 /*
 723  * Test and reset if a guest page is dirty
 724  */
 725 bool ptep_test_and_clear_uc(struct mm_struct *mm, unsigned long addr,
 726                        pte_t *ptep)
 727 {
 728         pgste_t pgste;
 729         pte_t pte;
 730         bool dirty;
 731         int nodat;
 732
 733         pgste = pgste_get_lock(ptep);
 734         dirty = !!(pgste_val(pgste) & PGSTE_UC_BIT);
 735         pgste_val(pgste) &= ~PGSTE_UC_BIT;
 736         pte = *ptep;
 737         if (dirty && (pte_val(pte) & _PAGE_PRESENT)) {
 738                 pgste = pgste_pte_notify(mm, addr, ptep, pgste);
 739                 nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 740                 ptep_ipte_global(mm, addr, ptep, nodat);
 741                 if (MACHINE_HAS_ESOP || !(pte_val(pte) & _PAGE_WRITE))
 742                         pte_val(pte) |= _PAGE_PROTECT;
 743                 else
 744                         pte_val(pte) |= _PAGE_INVALID;
 745                 *ptep = pte;
 746         }
 747         pgste_set_unlock(ptep, pgste);
 748         return dirty;
 749 }
 750 EXPORT_SYMBOL_GPL(ptep_test_and_clear_uc);
 751
 752 int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 753                           unsigned char key, bool nq)
 754 {
 755         unsigned long keyul, paddr;
 756         spinlock_t *ptl;
 757         pgste_t old, new;
 758         pmd_t *pmdp;
 759         pte_t *ptep;
 760
 761         pmdp = pmd_alloc_map(mm, addr);
 762         if (unlikely(!pmdp))
 763                 return -EFAULT;
 764
 765         ptl = pmd_lock(mm, pmdp);
 766         if (!pmd_present(*pmdp)) {
 767                 spin_unlock(ptl);
 768                 return -EFAULT;
 769         }
 770
 771         if (pmd_large(*pmdp)) {
 772                 paddr = pmd_val(*pmdp) & HPAGE_MASK;
 773                 paddr |= addr & ~HPAGE_MASK;
 774                 /*
 775                  * Huge pmds need quiescing operations, they are
 776                  * always mapped.
 777                  */
 778                 page_set_storage_key(paddr, key, 1);
 779                 spin_unlock(ptl);
 780                 return 0;
 781         }
 782         spin_unlock(ptl);
 783
 784         ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
 785         if (unlikely(!ptep))
 786                 return -EFAULT;
 787
 788         new = old = pgste_get_lock(ptep);
 789         pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT |
 790                             PGSTE_ACC_BITS | PGSTE_FP_BIT);
 791         keyul = (unsigned long) key;
 792         pgste_val(new) |= (keyul & (_PAGE_CHANGED | _PAGE_REFERENCED)) << 48;
 793         pgste_val(new) |= (keyul & (_PAGE_ACC_BITS | _PAGE_FP_BIT)) << 56;
 794         if (!(pte_val(*ptep) & _PAGE_INVALID)) {
 795                 unsigned long bits, skey;
 796
 797                 paddr = pte_val(*ptep) & PAGE_MASK;
 798                 skey = (unsigned long) page_get_storage_key(paddr);
 799                 bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED);
 800                 skey = key & (_PAGE_ACC_BITS | _PAGE_FP_BIT);
 801                 /* Set storage key ACC and FP */
 802                 page_set_storage_key(paddr, skey, !nq);
 803                 /* Merge host changed & referenced into pgste  */
 804                 pgste_val(new) |= bits << 52;
 805         }
 806         /* changing the guest storage key is considered a change of the page */
 807         if ((pgste_val(new) ^ pgste_val(old)) &
 808             (PGSTE_ACC_BITS | PGSTE_FP_BIT | PGSTE_GR_BIT | PGSTE_GC_BIT))
 809                 pgste_val(new) |= PGSTE_UC_BIT;
 810
 811         pgste_set_unlock(ptep, new);
 812         pte_unmap_unlock(ptep, ptl);
 813         return 0;
 814 }
 815 EXPORT_SYMBOL(set_guest_storage_key);
 816
 817 /**
 818  * Conditionally set a guest storage key (handling csske).
 819  * oldkey will be updated when either mr or mc is set and a pointer is given.
 820  *
 821  * Returns 0 if a guests storage key update wasn't necessary, 1 if the guest
 822  * storage key was updated and -EFAULT on access errors.
 823  */
 824 int cond_set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 825                                unsigned char key, unsigned char *oldkey,
 826                                bool nq, bool mr, bool mc)
 827 {
 828         unsigned char tmp, mask = _PAGE_ACC_BITS | _PAGE_FP_BIT;
 829         int rc;
 830
 831         /* we can drop the pgste lock between getting and setting the key */
 832         if (mr | mc) {
 833                 rc = get_guest_storage_key(current->mm, addr, &tmp);
 834                 if (rc)
 835                         return rc;
 836                 if (oldkey)
 837                         *oldkey = tmp;
 838                 if (!mr)
 839                         mask |= _PAGE_REFERENCED;
 840                 if (!mc)
 841                         mask |= _PAGE_CHANGED;
 842                 if (!((tmp ^ key) & mask))
 843                         return 0;
 844         }
 845         rc = set_guest_storage_key(current->mm, addr, key, nq);
 846         return rc < 0 ? rc : 1;
 847 }
 848 EXPORT_SYMBOL(cond_set_guest_storage_key);
 849
 850 /**
 851  * Reset a guest reference bit (rrbe), returning the reference and changed bit.
 852  *
 853  * Returns < 0 in case of error, otherwise the cc to be reported to the guest.
 854  */
 855 int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr)
 856 {
 857         spinlock_t *ptl;
 858         unsigned long paddr;
 859         pgste_t old, new;
 860         pmd_t *pmdp;
 861         pte_t *ptep;
 862         int cc = 0;
 863
 864         pmdp = pmd_alloc_map(mm, addr);
 865         if (unlikely(!pmdp))
 866                 return -EFAULT;
 867
 868         ptl = pmd_lock(mm, pmdp);
 869         if (!pmd_present(*pmdp)) {
 870                 spin_unlock(ptl);
 871                 return -EFAULT;
 872         }
 873
 874         if (pmd_large(*pmdp)) {
 875                 paddr = pmd_val(*pmdp) & HPAGE_MASK;
 876                 paddr |= addr & ~HPAGE_MASK;
 877                 cc = page_reset_referenced(paddr);
 878                 spin_unlock(ptl);
 879                 return cc;
 880         }
 881         spin_unlock(ptl);
 882
 883         ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
 884         if (unlikely(!ptep))
 885                 return -EFAULT;
 886
 887         new = old = pgste_get_lock(ptep);
 888         /* Reset guest reference bit only */
 889         pgste_val(new) &= ~PGSTE_GR_BIT;
 890
 891         if (!(pte_val(*ptep) & _PAGE_INVALID)) {
 892                 paddr = pte_val(*ptep) & PAGE_MASK;
 893                 cc = page_reset_referenced(paddr);
 894                 /* Merge real referenced bit into host-set */
 895                 pgste_val(new) |= ((unsigned long) cc << 53) & PGSTE_HR_BIT;
 896         }
 897         /* Reflect guest's logical view, not physical */
 898         cc |= (pgste_val(old) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 49;
 899         /* Changing the guest storage key is considered a change of the page */
 900         if ((pgste_val(new) ^ pgste_val(old)) & PGSTE_GR_BIT)
 901                 pgste_val(new) |= PGSTE_UC_BIT;
 902
 903         pgste_set_unlock(ptep, new);
 904         pte_unmap_unlock(ptep, ptl);
 905         return cc;
 906 }
 907 EXPORT_SYMBOL(reset_guest_reference_bit);
 908
 909 int get_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 910                           unsigned char *key)
 911 {
 912         unsigned long paddr;
 913         spinlock_t *ptl;
 914         pgste_t pgste;
 915         pmd_t *pmdp;
 916         pte_t *ptep;
 917
 918         pmdp = pmd_alloc_map(mm, addr);
 919         if (unlikely(!pmdp))
 920                 return -EFAULT;
 921
 922         ptl = pmd_lock(mm, pmdp);
 923         if (!pmd_present(*pmdp)) {
 924                 /* Not yet mapped memory has a zero key */
 925                 spin_unlock(ptl);
 926                 *key = 0;
 927                 return 0;
 928         }
 929
 930         if (pmd_large(*pmdp)) {
 931                 paddr = pmd_val(*pmdp) & HPAGE_MASK;
 932                 paddr |= addr & ~HPAGE_MASK;
 933                 *key = page_get_storage_key(paddr);
 934                 spin_unlock(ptl);
 935                 return 0;
 936         }
 937         spin_unlock(ptl);
 938
 939         ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
 940         if (unlikely(!ptep))
 941                 return -EFAULT;
 942
 943         pgste = pgste_get_lock(ptep);
 944         *key = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
 945         paddr = pte_val(*ptep) & PAGE_MASK;
 946         if (!(pte_val(*ptep) & _PAGE_INVALID))
 947                 *key = page_get_storage_key(paddr);
 948         /* Reflect guest's logical view, not physical */
 949         *key |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48;
 950         pgste_set_unlock(ptep, pgste);
 951         pte_unmap_unlock(ptep, ptl);
 952         return 0;
 953 }
 954 EXPORT_SYMBOL(get_guest_storage_key);
 955
 956 /**
 957  * pgste_perform_essa - perform ESSA actions on the PGSTE.
 958  * @mm: the memory context. It must have PGSTEs, no check is performed here!
 959  * @hva: the host virtual address of the page whose PGSTE is to be processed
 960  * @orc: the specific action to perform, see the ESSA_SET_* macros.
 961  * @oldpte: the PTE will be saved there if the pointer is not NULL.
 962  * @oldpgste: the old PGSTE will be saved there if the pointer is not NULL.
 963  *
 964  * Return: 1 if the page is to be added to the CBRL, otherwise 0,
 965  *         or < 0 in case of error. -EINVAL is returned for invalid values
 966  *         of orc, -EFAULT for invalid addresses.
 967  */
 968 int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc,
 969                         unsigned long *oldpte, unsigned long *oldpgste)
 970 {
 971         unsigned long pgstev;
 972         spinlock_t *ptl;
 973         pgste_t pgste;
 974         pte_t *ptep;
 975         int res = 0;
 976
 977         WARN_ON_ONCE(orc > ESSA_MAX);
 978         if (unlikely(orc > ESSA_MAX))
 979                 return -EINVAL;
 980         ptep = get_locked_pte(mm, hva, &ptl);
 981         if (unlikely(!ptep))
 982                 return -EFAULT;
 983         pgste = pgste_get_lock(ptep);
 984         pgstev = pgste_val(pgste);
 985         if (oldpte)
 986                 *oldpte = pte_val(*ptep);
 987         if (oldpgste)
 988                 *oldpgste = pgstev;
 989
 990         switch (orc) {
 991         case ESSA_GET_STATE:
 992                 break;
 993         case ESSA_SET_STABLE:
 994                 pgstev &= ~(_PGSTE_GPS_USAGE_MASK | _PGSTE_GPS_NODAT);
 995                 pgstev |= _PGSTE_GPS_USAGE_STABLE;
 996                 break;
 997         case ESSA_SET_UNUSED:
 998                 pgstev &= ~_PGSTE_GPS_USAGE_MASK;
 999                 pgstev |= _PGSTE_GPS_USAGE_UNUSED;
1000                 if (pte_val(*ptep) & _PAGE_INVALID)
1001                         res = 1;
1002                 break;
1003         case ESSA_SET_VOLATILE:
1004                 pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1005                 pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
1006                 if (pte_val(*ptep) & _PAGE_INVALID)
1007                         res = 1;
1008                 break;
1009         case ESSA_SET_POT_VOLATILE:
1010                 pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1011                 if (!(pte_val(*ptep) & _PAGE_INVALID)) {
1012                         pgstev |= _PGSTE_GPS_USAGE_POT_VOLATILE;
1013                         break;
1014                 }
1015                 if (pgstev & _PGSTE_GPS_ZERO) {
1016                         pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
1017                         break;
1018                 }
1019                 if (!(pgstev & PGSTE_GC_BIT)) {
1020                         pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
1021                         res = 1;
1022                         break;
1023                 }
1024                 break;
1025         case ESSA_SET_STABLE_RESIDENT:
1026                 pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1027                 pgstev |= _PGSTE_GPS_USAGE_STABLE;
1028                 /*
1029                  * Since the resident state can go away any time after this
1030                  * call, we will not make this page resident. We can revisit
1031                  * this decision if a guest will ever start using this.
1032                  */
1033                 break;
1034         case ESSA_SET_STABLE_IF_RESIDENT:
1035                 if (!(pte_val(*ptep) & _PAGE_INVALID)) {
1036                         pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1037                         pgstev |= _PGSTE_GPS_USAGE_STABLE;
1038                 }
1039                 break;
1040         case ESSA_SET_STABLE_NODAT:
1041                 pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1042                 pgstev |= _PGSTE_GPS_USAGE_STABLE | _PGSTE_GPS_NODAT;
1043                 break;
1044         default:
1045                 /* we should never get here! */
1046                 break;
1047         }
1048         /* If we are discarding a page, set it to logical zero */
1049         if (res)
1050                 pgstev |= _PGSTE_GPS_ZERO;
1051
1052         pgste_val(pgste) = pgstev;
1053         pgste_set_unlock(ptep, pgste);
1054         pte_unmap_unlock(ptep, ptl);
1055         return res;
1056 }
1057 EXPORT_SYMBOL(pgste_perform_essa);
1058
1059 /**
1060  * set_pgste_bits - set specific PGSTE bits.
1061  * @mm: the memory context. It must have PGSTEs, no check is performed here!
1062  * @hva: the host virtual address of the page whose PGSTE is to be processed
1063  * @bits: a bitmask representing the bits that will be touched
1064  * @value: the values of the bits to be written. Only the bits in the mask
1065  *         will be written.
1066  *
1067  * Return: 0 on success, < 0 in case of error.
1068  */
1069 int set_pgste_bits(struct mm_struct *mm, unsigned long hva,
1070                         unsigned long bits, unsigned long value)
1071 {
1072         spinlock_t *ptl;
1073         pgste_t new;
1074         pte_t *ptep;
1075
1076         ptep = get_locked_pte(mm, hva, &ptl);
1077         if (unlikely(!ptep))
1078                 return -EFAULT;
1079         new = pgste_get_lock(ptep);
1080
1081         pgste_val(new) &= ~bits;
1082         pgste_val(new) |= value & bits;
1083
1084         pgste_set_unlock(ptep, new);
1085         pte_unmap_unlock(ptep, ptl);
1086         return 0;
1087 }
1088 EXPORT_SYMBOL(set_pgste_bits);
1089
1090 /**
1091  * get_pgste - get the current PGSTE for the given address.
1092  * @mm: the memory context. It must have PGSTEs, no check is performed here!
1093  * @hva: the host virtual address of the page whose PGSTE is to be processed
1094  * @pgstep: will be written with the current PGSTE for the given address.
1095  *
1096  * Return: 0 on success, < 0 in case of error.
1097  */
1098 int get_pgste(struct mm_struct *mm, unsigned long hva, unsigned long *pgstep)
1099 {
1100         spinlock_t *ptl;
1101         pte_t *ptep;
1102
1103         ptep = get_locked_pte(mm, hva, &ptl);
1104         if (unlikely(!ptep))
1105                 return -EFAULT;
1106         *pgstep = pgste_val(pgste_get(ptep));
1107         pte_unmap_unlock(ptep, ptl);
1108         return 0;
1109 }
1110 EXPORT_SYMBOL(get_pgste);
1111 #endif