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 vm_area_struct *vma, unsigned long addr,
 305                              pte_t *ptep)
 306 {
 307         pgste_t pgste;
 308         pte_t old;
 309         int nodat;
 310         struct mm_struct *mm = vma->vm_mm;
 311
 312         preempt_disable();
 313         pgste = ptep_xchg_start(mm, addr, ptep);
 314         nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 315         old = ptep_flush_lazy(mm, addr, ptep, nodat);
 316         if (mm_has_pgste(mm)) {
 317                 pgste = pgste_update_all(old, pgste, mm);
 318                 pgste_set(ptep, pgste);
 319         }
 320         return old;
 321 }
 322
 323 void ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr,
 324                              pte_t *ptep, pte_t old_pte, pte_t pte)
 325 {
 326         pgste_t pgste;
 327         struct mm_struct *mm = vma->vm_mm;
 328
 329         if (!MACHINE_HAS_NX)
 330                 pte_val(pte) &= ~_PAGE_NOEXEC;
 331         if (mm_has_pgste(mm)) {
 332                 pgste = pgste_get(ptep);
 333                 pgste_set_key(ptep, pgste, pte, mm);
 334                 pgste = pgste_set_pte(ptep, pgste, pte);
 335                 pgste_set_unlock(ptep, pgste);
 336         } else {
 337                 *ptep = pte;
 338         }
 339         preempt_enable();
 340 }
 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 #ifdef CONFIG_PGSTE
 414 static pmd_t *pmd_alloc_map(struct mm_struct *mm, unsigned long addr)
 415 {
 416         pgd_t *pgd;
 417         p4d_t *p4d;
 418         pud_t *pud;
 419         pmd_t *pmd;
 420
 421         pgd = pgd_offset(mm, addr);
 422         p4d = p4d_alloc(mm, pgd, addr);
 423         if (!p4d)
 424                 return NULL;
 425         pud = pud_alloc(mm, p4d, addr);
 426         if (!pud)
 427                 return NULL;
 428         pmd = pmd_alloc(mm, pud, addr);
 429         return pmd;
 430 }
 431 #endif
 432
 433 pmd_t pmdp_xchg_direct(struct mm_struct *mm, unsigned long addr,
 434                        pmd_t *pmdp, pmd_t new)
 435 {
 436         pmd_t old;
 437
 438         preempt_disable();
 439         old = pmdp_flush_direct(mm, addr, pmdp);
 440         *pmdp = new;
 441         preempt_enable();
 442         return old;
 443 }
 444 EXPORT_SYMBOL(pmdp_xchg_direct);
 445
 446 pmd_t pmdp_xchg_lazy(struct mm_struct *mm, unsigned long addr,
 447                      pmd_t *pmdp, pmd_t new)
 448 {
 449         pmd_t old;
 450
 451         preempt_disable();
 452         old = pmdp_flush_lazy(mm, addr, pmdp);
 453         *pmdp = new;
 454         preempt_enable();
 455         return old;
 456 }
 457 EXPORT_SYMBOL(pmdp_xchg_lazy);
 458
 459 static inline void pudp_idte_local(struct mm_struct *mm,
 460                                    unsigned long addr, pud_t *pudp)
 461 {
 462         if (MACHINE_HAS_TLB_GUEST)
 463                 __pudp_idte(addr, pudp, IDTE_NODAT | IDTE_GUEST_ASCE,
 464                             mm->context.asce, IDTE_LOCAL);
 465         else
 466                 __pudp_idte(addr, pudp, 0, 0, IDTE_LOCAL);
 467 }
 468
 469 static inline void pudp_idte_global(struct mm_struct *mm,
 470                                     unsigned long addr, pud_t *pudp)
 471 {
 472         if (MACHINE_HAS_TLB_GUEST)
 473                 __pudp_idte(addr, pudp, IDTE_NODAT | IDTE_GUEST_ASCE,
 474                             mm->context.asce, IDTE_GLOBAL);
 475         else if (MACHINE_HAS_IDTE)
 476                 __pudp_idte(addr, pudp, 0, 0, IDTE_GLOBAL);
 477         else
 478                 /*
 479                  * Invalid bit position is the same for pmd and pud, so we can
 480                  * re-use _pmd_csp() here
 481                  */
 482                 __pmdp_csp((pmd_t *) pudp);
 483 }
 484
 485 static inline pud_t pudp_flush_direct(struct mm_struct *mm,
 486                                       unsigned long addr, pud_t *pudp)
 487 {
 488         pud_t old;
 489
 490         old = *pudp;
 491         if (pud_val(old) & _REGION_ENTRY_INVALID)
 492                 return old;
 493         atomic_inc(&mm->context.flush_count);
 494         if (MACHINE_HAS_TLB_LC &&
 495             cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
 496                 pudp_idte_local(mm, addr, pudp);
 497         else
 498                 pudp_idte_global(mm, addr, pudp);
 499         atomic_dec(&mm->context.flush_count);
 500         return old;
 501 }
 502
 503 pud_t pudp_xchg_direct(struct mm_struct *mm, unsigned long addr,
 504                        pud_t *pudp, pud_t new)
 505 {
 506         pud_t old;
 507
 508         preempt_disable();
 509         old = pudp_flush_direct(mm, addr, pudp);
 510         *pudp = new;
 511         preempt_enable();
 512         return old;
 513 }
 514 EXPORT_SYMBOL(pudp_xchg_direct);
 515
 516 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 517 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 518                                 pgtable_t pgtable)
 519 {
 520         struct list_head *lh = (struct list_head *) pgtable;
 521
 522         assert_spin_locked(pmd_lockptr(mm, pmdp));
 523
 524         /* FIFO */
 525         if (!pmd_huge_pte(mm, pmdp))
 526                 INIT_LIST_HEAD(lh);
 527         else
 528                 list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
 529         pmd_huge_pte(mm, pmdp) = pgtable;
 530 }
 531
 532 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 533 {
 534         struct list_head *lh;
 535         pgtable_t pgtable;
 536         pte_t *ptep;
 537
 538         assert_spin_locked(pmd_lockptr(mm, pmdp));
 539
 540         /* FIFO */
 541         pgtable = pmd_huge_pte(mm, pmdp);
 542         lh = (struct list_head *) pgtable;
 543         if (list_empty(lh))
 544                 pmd_huge_pte(mm, pmdp) = NULL;
 545         else {
 546                 pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
 547                 list_del(lh);
 548         }
 549         ptep = (pte_t *) pgtable;
 550         pte_val(*ptep) = _PAGE_INVALID;
 551         ptep++;
 552         pte_val(*ptep) = _PAGE_INVALID;
 553         return pgtable;
 554 }
 555 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 556
 557 #ifdef CONFIG_PGSTE
 558 void ptep_set_pte_at(struct mm_struct *mm, unsigned long addr,
 559                      pte_t *ptep, pte_t entry)
 560 {
 561         pgste_t pgste;
 562
 563         /* the mm_has_pgste() check is done in set_pte_at() */
 564         preempt_disable();
 565         pgste = pgste_get_lock(ptep);
 566         pgste_val(pgste) &= ~_PGSTE_GPS_ZERO;
 567         pgste_set_key(ptep, pgste, entry, mm);
 568         pgste = pgste_set_pte(ptep, pgste, entry);
 569         pgste_set_unlock(ptep, pgste);
 570         preempt_enable();
 571 }
 572
 573 void ptep_set_notify(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 574 {
 575         pgste_t pgste;
 576
 577         preempt_disable();
 578         pgste = pgste_get_lock(ptep);
 579         pgste_val(pgste) |= PGSTE_IN_BIT;
 580         pgste_set_unlock(ptep, pgste);
 581         preempt_enable();
 582 }
 583
 584 /**
 585  * ptep_force_prot - change access rights of a locked pte
 586  * @mm: pointer to the process mm_struct
 587  * @addr: virtual address in the guest address space
 588  * @ptep: pointer to the page table entry
 589  * @prot: indicates guest access rights: PROT_NONE, PROT_READ or PROT_WRITE
 590  * @bit: pgste bit to set (e.g. for notification)
 591  *
 592  * Returns 0 if the access rights were changed and -EAGAIN if the current
 593  * and requested access rights are incompatible.
 594  */
 595 int ptep_force_prot(struct mm_struct *mm, unsigned long addr,
 596                     pte_t *ptep, int prot, unsigned long bit)
 597 {
 598         pte_t entry;
 599         pgste_t pgste;
 600         int pte_i, pte_p, nodat;
 601
 602         pgste = pgste_get_lock(ptep);
 603         entry = *ptep;
 604         /* Check pte entry after all locks have been acquired */
 605         pte_i = pte_val(entry) & _PAGE_INVALID;
 606         pte_p = pte_val(entry) & _PAGE_PROTECT;
 607         if ((pte_i && (prot != PROT_NONE)) ||
 608             (pte_p && (prot & PROT_WRITE))) {
 609                 pgste_set_unlock(ptep, pgste);
 610                 return -EAGAIN;
 611         }
 612         /* Change access rights and set pgste bit */
 613         nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 614         if (prot == PROT_NONE && !pte_i) {
 615                 ptep_flush_direct(mm, addr, ptep, nodat);
 616                 pgste = pgste_update_all(entry, pgste, mm);
 617                 pte_val(entry) |= _PAGE_INVALID;
 618         }
 619         if (prot == PROT_READ && !pte_p) {
 620                 ptep_flush_direct(mm, addr, ptep, nodat);
 621                 pte_val(entry) &= ~_PAGE_INVALID;
 622                 pte_val(entry) |= _PAGE_PROTECT;
 623         }
 624         pgste_val(pgste) |= bit;
 625         pgste = pgste_set_pte(ptep, pgste, entry);
 626         pgste_set_unlock(ptep, pgste);
 627         return 0;
 628 }
 629
 630 int ptep_shadow_pte(struct mm_struct *mm, unsigned long saddr,
 631                     pte_t *sptep, pte_t *tptep, pte_t pte)
 632 {
 633         pgste_t spgste, tpgste;
 634         pte_t spte, tpte;
 635         int rc = -EAGAIN;
 636
 637         if (!(pte_val(*tptep) & _PAGE_INVALID))
 638                 return 0;       /* already shadowed */
 639         spgste = pgste_get_lock(sptep);
 640         spte = *sptep;
 641         if (!(pte_val(spte) & _PAGE_INVALID) &&
 642             !((pte_val(spte) & _PAGE_PROTECT) &&
 643               !(pte_val(pte) & _PAGE_PROTECT))) {
 644                 pgste_val(spgste) |= PGSTE_VSIE_BIT;
 645                 tpgste = pgste_get_lock(tptep);
 646                 pte_val(tpte) = (pte_val(spte) & PAGE_MASK) |
 647                                 (pte_val(pte) & _PAGE_PROTECT);
 648                 /* don't touch the storage key - it belongs to parent pgste */
 649                 tpgste = pgste_set_pte(tptep, tpgste, tpte);
 650                 pgste_set_unlock(tptep, tpgste);
 651                 rc = 1;
 652         }
 653         pgste_set_unlock(sptep, spgste);
 654         return rc;
 655 }
 656
 657 void ptep_unshadow_pte(struct mm_struct *mm, unsigned long saddr, pte_t *ptep)
 658 {
 659         pgste_t pgste;
 660         int nodat;
 661
 662         pgste = pgste_get_lock(ptep);
 663         /* notifier is called by the caller */
 664         nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 665         ptep_flush_direct(mm, saddr, ptep, nodat);
 666         /* don't touch the storage key - it belongs to parent pgste */
 667         pgste = pgste_set_pte(ptep, pgste, __pte(_PAGE_INVALID));
 668         pgste_set_unlock(ptep, pgste);
 669 }
 670
 671 static void ptep_zap_swap_entry(struct mm_struct *mm, swp_entry_t entry)
 672 {
 673         if (!non_swap_entry(entry))
 674                 dec_mm_counter(mm, MM_SWAPENTS);
 675         else if (is_migration_entry(entry)) {
 676                 struct page *page = migration_entry_to_page(entry);
 677
 678                 dec_mm_counter(mm, mm_counter(page));
 679         }
 680         free_swap_and_cache(entry);
 681 }
 682
 683 void ptep_zap_unused(struct mm_struct *mm, unsigned long addr,
 684                      pte_t *ptep, int reset)
 685 {
 686         unsigned long pgstev;
 687         pgste_t pgste;
 688         pte_t pte;
 689
 690         /* Zap unused and logically-zero pages */
 691         preempt_disable();
 692         pgste = pgste_get_lock(ptep);
 693         pgstev = pgste_val(pgste);
 694         pte = *ptep;
 695         if (!reset && pte_swap(pte) &&
 696             ((pgstev & _PGSTE_GPS_USAGE_MASK) == _PGSTE_GPS_USAGE_UNUSED ||
 697              (pgstev & _PGSTE_GPS_ZERO))) {
 698                 ptep_zap_swap_entry(mm, pte_to_swp_entry(pte));
 699                 pte_clear(mm, addr, ptep);
 700         }
 701         if (reset)
 702                 pgste_val(pgste) &= ~_PGSTE_GPS_USAGE_MASK;
 703         pgste_set_unlock(ptep, pgste);
 704         preempt_enable();
 705 }
 706
 707 void ptep_zap_key(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 708 {
 709         unsigned long ptev;
 710         pgste_t pgste;
 711
 712         /* Clear storage key ACC and F, but set R/C */
 713         preempt_disable();
 714         pgste = pgste_get_lock(ptep);
 715         pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT);
 716         pgste_val(pgste) |= PGSTE_GR_BIT | PGSTE_GC_BIT;
 717         ptev = pte_val(*ptep);
 718         if (!(ptev & _PAGE_INVALID) && (ptev & _PAGE_WRITE))
 719                 page_set_storage_key(ptev & PAGE_MASK, PAGE_DEFAULT_KEY, 1);
 720         pgste_set_unlock(ptep, pgste);
 721         preempt_enable();
 722 }
 723
 724 /*
 725  * Test and reset if a guest page is dirty
 726  */
 727 bool ptep_test_and_clear_uc(struct mm_struct *mm, unsigned long addr,
 728                        pte_t *ptep)
 729 {
 730         pgste_t pgste;
 731         pte_t pte;
 732         bool dirty;
 733         int nodat;
 734
 735         pgste = pgste_get_lock(ptep);
 736         dirty = !!(pgste_val(pgste) & PGSTE_UC_BIT);
 737         pgste_val(pgste) &= ~PGSTE_UC_BIT;
 738         pte = *ptep;
 739         if (dirty && (pte_val(pte) & _PAGE_PRESENT)) {
 740                 pgste = pgste_pte_notify(mm, addr, ptep, pgste);
 741                 nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 742                 ptep_ipte_global(mm, addr, ptep, nodat);
 743                 if (MACHINE_HAS_ESOP || !(pte_val(pte) & _PAGE_WRITE))
 744                         pte_val(pte) |= _PAGE_PROTECT;
 745                 else
 746                         pte_val(pte) |= _PAGE_INVALID;
 747                 *ptep = pte;
 748         }
 749         pgste_set_unlock(ptep, pgste);
 750         return dirty;
 751 }
 752 EXPORT_SYMBOL_GPL(ptep_test_and_clear_uc);
 753
 754 int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 755                           unsigned char key, bool nq)
 756 {
 757         unsigned long keyul, paddr;
 758         spinlock_t *ptl;
 759         pgste_t old, new;
 760         pmd_t *pmdp;
 761         pte_t *ptep;
 762
 763         pmdp = pmd_alloc_map(mm, addr);
 764         if (unlikely(!pmdp))
 765                 return -EFAULT;
 766
 767         ptl = pmd_lock(mm, pmdp);
 768         if (!pmd_present(*pmdp)) {
 769                 spin_unlock(ptl);
 770                 return -EFAULT;
 771         }
 772
 773         if (pmd_large(*pmdp)) {
 774                 paddr = pmd_val(*pmdp) & HPAGE_MASK;
 775                 paddr |= addr & ~HPAGE_MASK;
 776                 /*
 777                  * Huge pmds need quiescing operations, they are
 778                  * always mapped.
 779                  */
 780                 page_set_storage_key(paddr, key, 1);
 781                 spin_unlock(ptl);
 782                 return 0;
 783         }
 784         spin_unlock(ptl);
 785
 786         ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
 787         if (unlikely(!ptep))
 788                 return -EFAULT;
 789
 790         new = old = pgste_get_lock(ptep);
 791         pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT |
 792                             PGSTE_ACC_BITS | PGSTE_FP_BIT);
 793         keyul = (unsigned long) key;
 794         pgste_val(new) |= (keyul & (_PAGE_CHANGED | _PAGE_REFERENCED)) << 48;
 795         pgste_val(new) |= (keyul & (_PAGE_ACC_BITS | _PAGE_FP_BIT)) << 56;
 796         if (!(pte_val(*ptep) & _PAGE_INVALID)) {
 797                 unsigned long bits, skey;
 798
 799                 paddr = pte_val(*ptep) & PAGE_MASK;
 800                 skey = (unsigned long) page_get_storage_key(paddr);
 801                 bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED);
 802                 skey = key & (_PAGE_ACC_BITS | _PAGE_FP_BIT);
 803                 /* Set storage key ACC and FP */
 804                 page_set_storage_key(paddr, skey, !nq);
 805                 /* Merge host changed & referenced into pgste  */
 806                 pgste_val(new) |= bits << 52;
 807         }
 808         /* changing the guest storage key is considered a change of the page */
 809         if ((pgste_val(new) ^ pgste_val(old)) &
 810             (PGSTE_ACC_BITS | PGSTE_FP_BIT | PGSTE_GR_BIT | PGSTE_GC_BIT))
 811                 pgste_val(new) |= PGSTE_UC_BIT;
 812
 813         pgste_set_unlock(ptep, new);
 814         pte_unmap_unlock(ptep, ptl);
 815         return 0;
 816 }
 817 EXPORT_SYMBOL(set_guest_storage_key);
 818
 819 /**
 820  * Conditionally set a guest storage key (handling csske).
 821  * oldkey will be updated when either mr or mc is set and a pointer is given.
 822  *
 823  * Returns 0 if a guests storage key update wasn't necessary, 1 if the guest
 824  * storage key was updated and -EFAULT on access errors.
 825  */
 826 int cond_set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 827                                unsigned char key, unsigned char *oldkey,
 828                                bool nq, bool mr, bool mc)
 829 {
 830         unsigned char tmp, mask = _PAGE_ACC_BITS | _PAGE_FP_BIT;
 831         int rc;
 832
 833         /* we can drop the pgste lock between getting and setting the key */
 834         if (mr | mc) {
 835                 rc = get_guest_storage_key(current->mm, addr, &tmp);
 836                 if (rc)
 837                         return rc;
 838                 if (oldkey)
 839                         *oldkey = tmp;
 840                 if (!mr)
 841                         mask |= _PAGE_REFERENCED;
 842                 if (!mc)
 843                         mask |= _PAGE_CHANGED;
 844                 if (!((tmp ^ key) & mask))
 845                         return 0;
 846         }
 847         rc = set_guest_storage_key(current->mm, addr, key, nq);
 848         return rc < 0 ? rc : 1;
 849 }
 850 EXPORT_SYMBOL(cond_set_guest_storage_key);
 851
 852 /**
 853  * Reset a guest reference bit (rrbe), returning the reference and changed bit.
 854  *
 855  * Returns < 0 in case of error, otherwise the cc to be reported to the guest.
 856  */
 857 int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr)
 858 {
 859         spinlock_t *ptl;
 860         unsigned long paddr;
 861         pgste_t old, new;
 862         pmd_t *pmdp;
 863         pte_t *ptep;
 864         int cc = 0;
 865
 866         pmdp = pmd_alloc_map(mm, addr);
 867         if (unlikely(!pmdp))
 868                 return -EFAULT;
 869
 870         ptl = pmd_lock(mm, pmdp);
 871         if (!pmd_present(*pmdp)) {
 872                 spin_unlock(ptl);
 873                 return -EFAULT;
 874         }
 875
 876         if (pmd_large(*pmdp)) {
 877                 paddr = pmd_val(*pmdp) & HPAGE_MASK;
 878                 paddr |= addr & ~HPAGE_MASK;
 879                 cc = page_reset_referenced(paddr);
 880                 spin_unlock(ptl);
 881                 return cc;
 882         }
 883         spin_unlock(ptl);
 884
 885         ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
 886         if (unlikely(!ptep))
 887                 return -EFAULT;
 888
 889         new = old = pgste_get_lock(ptep);
 890         /* Reset guest reference bit only */
 891         pgste_val(new) &= ~PGSTE_GR_BIT;
 892
 893         if (!(pte_val(*ptep) & _PAGE_INVALID)) {
 894                 paddr = pte_val(*ptep) & PAGE_MASK;
 895                 cc = page_reset_referenced(paddr);
 896                 /* Merge real referenced bit into host-set */
 897                 pgste_val(new) |= ((unsigned long) cc << 53) & PGSTE_HR_BIT;
 898         }
 899         /* Reflect guest's logical view, not physical */
 900         cc |= (pgste_val(old) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 49;
 901         /* Changing the guest storage key is considered a change of the page */
 902         if ((pgste_val(new) ^ pgste_val(old)) & PGSTE_GR_BIT)
 903                 pgste_val(new) |= PGSTE_UC_BIT;
 904
 905         pgste_set_unlock(ptep, new);
 906         pte_unmap_unlock(ptep, ptl);
 907         return cc;
 908 }
 909 EXPORT_SYMBOL(reset_guest_reference_bit);
 910
 911 int get_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 912                           unsigned char *key)
 913 {
 914         unsigned long paddr;
 915         spinlock_t *ptl;
 916         pgste_t pgste;
 917         pmd_t *pmdp;
 918         pte_t *ptep;
 919
 920         pmdp = pmd_alloc_map(mm, addr);
 921         if (unlikely(!pmdp))
 922                 return -EFAULT;
 923
 924         ptl = pmd_lock(mm, pmdp);
 925         if (!pmd_present(*pmdp)) {
 926                 /* Not yet mapped memory has a zero key */
 927                 spin_unlock(ptl);
 928                 *key = 0;
 929                 return 0;
 930         }
 931
 932         if (pmd_large(*pmdp)) {
 933                 paddr = pmd_val(*pmdp) & HPAGE_MASK;
 934                 paddr |= addr & ~HPAGE_MASK;
 935                 *key = page_get_storage_key(paddr);
 936                 spin_unlock(ptl);
 937                 return 0;
 938         }
 939         spin_unlock(ptl);
 940
 941         ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
 942         if (unlikely(!ptep))
 943                 return -EFAULT;
 944
 945         pgste = pgste_get_lock(ptep);
 946         *key = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
 947         paddr = pte_val(*ptep) & PAGE_MASK;
 948         if (!(pte_val(*ptep) & _PAGE_INVALID))
 949                 *key = page_get_storage_key(paddr);
 950         /* Reflect guest's logical view, not physical */
 951         *key |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48;
 952         pgste_set_unlock(ptep, pgste);
 953         pte_unmap_unlock(ptep, ptl);
 954         return 0;
 955 }
 956 EXPORT_SYMBOL(get_guest_storage_key);
 957
 958 /**
 959  * pgste_perform_essa - perform ESSA actions on the PGSTE.
 960  * @mm: the memory context. It must have PGSTEs, no check is performed here!
 961  * @hva: the host virtual address of the page whose PGSTE is to be processed
 962  * @orc: the specific action to perform, see the ESSA_SET_* macros.
 963  * @oldpte: the PTE will be saved there if the pointer is not NULL.
 964  * @oldpgste: the old PGSTE will be saved there if the pointer is not NULL.
 965  *
 966  * Return: 1 if the page is to be added to the CBRL, otherwise 0,
 967  *         or < 0 in case of error. -EINVAL is returned for invalid values
 968  *         of orc, -EFAULT for invalid addresses.
 969  */
 970 int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc,
 971                         unsigned long *oldpte, unsigned long *oldpgste)
 972 {
 973         unsigned long pgstev;
 974         spinlock_t *ptl;
 975         pgste_t pgste;
 976         pte_t *ptep;
 977         int res = 0;
 978
 979         WARN_ON_ONCE(orc > ESSA_MAX);
 980         if (unlikely(orc > ESSA_MAX))
 981                 return -EINVAL;
 982         ptep = get_locked_pte(mm, hva, &ptl);
 983         if (unlikely(!ptep))
 984                 return -EFAULT;
 985         pgste = pgste_get_lock(ptep);
 986         pgstev = pgste_val(pgste);
 987         if (oldpte)
 988                 *oldpte = pte_val(*ptep);
 989         if (oldpgste)
 990                 *oldpgste = pgstev;
 991
 992         switch (orc) {
 993         case ESSA_GET_STATE:
 994                 break;
 995         case ESSA_SET_STABLE:
 996                 pgstev &= ~(_PGSTE_GPS_USAGE_MASK | _PGSTE_GPS_NODAT);
 997                 pgstev |= _PGSTE_GPS_USAGE_STABLE;
 998                 break;
 999         case ESSA_SET_UNUSED:
1000                 pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1001                 pgstev |= _PGSTE_GPS_USAGE_UNUSED;
1002                 if (pte_val(*ptep) & _PAGE_INVALID)
1003                         res = 1;
1004                 break;
1005         case ESSA_SET_VOLATILE:
1006                 pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1007                 pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
1008                 if (pte_val(*ptep) & _PAGE_INVALID)
1009                         res = 1;
1010                 break;
1011         case ESSA_SET_POT_VOLATILE:
1012                 pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1013                 if (!(pte_val(*ptep) & _PAGE_INVALID)) {
1014                         pgstev |= _PGSTE_GPS_USAGE_POT_VOLATILE;
1015                         break;
1016                 }
1017                 if (pgstev & _PGSTE_GPS_ZERO) {
1018                         pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
1019                         break;
1020                 }
1021                 if (!(pgstev & PGSTE_GC_BIT)) {
1022                         pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
1023                         res = 1;
1024                         break;
1025                 }
1026                 break;
1027         case ESSA_SET_STABLE_RESIDENT:
1028                 pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1029                 pgstev |= _PGSTE_GPS_USAGE_STABLE;
1030                 /*
1031                  * Since the resident state can go away any time after this
1032                  * call, we will not make this page resident. We can revisit
1033                  * this decision if a guest will ever start using this.
1034                  */
1035                 break;
1036         case ESSA_SET_STABLE_IF_RESIDENT:
1037                 if (!(pte_val(*ptep) & _PAGE_INVALID)) {
1038                         pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1039                         pgstev |= _PGSTE_GPS_USAGE_STABLE;
1040                 }
1041                 break;
1042         case ESSA_SET_STABLE_NODAT:
1043                 pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1044                 pgstev |= _PGSTE_GPS_USAGE_STABLE | _PGSTE_GPS_NODAT;
1045                 break;
1046         default:
1047                 /* we should never get here! */
1048                 break;
1049         }
1050         /* If we are discarding a page, set it to logical zero */
1051         if (res)
1052                 pgstev |= _PGSTE_GPS_ZERO;
1053
1054         pgste_val(pgste) = pgstev;
1055         pgste_set_unlock(ptep, pgste);
1056         pte_unmap_unlock(ptep, ptl);
1057         return res;
1058 }
1059 EXPORT_SYMBOL(pgste_perform_essa);
1060
1061 /**
1062  * set_pgste_bits - set specific PGSTE bits.
1063  * @mm: the memory context. It must have PGSTEs, no check is performed here!
1064  * @hva: the host virtual address of the page whose PGSTE is to be processed
1065  * @bits: a bitmask representing the bits that will be touched
1066  * @value: the values of the bits to be written. Only the bits in the mask
1067  *         will be written.
1068  *
1069  * Return: 0 on success, < 0 in case of error.
1070  */
1071 int set_pgste_bits(struct mm_struct *mm, unsigned long hva,
1072                         unsigned long bits, unsigned long value)
1073 {
1074         spinlock_t *ptl;
1075         pgste_t new;
1076         pte_t *ptep;
1077
1078         ptep = get_locked_pte(mm, hva, &ptl);
1079         if (unlikely(!ptep))
1080                 return -EFAULT;
1081         new = pgste_get_lock(ptep);
1082
1083         pgste_val(new) &= ~bits;
1084         pgste_val(new) |= value & bits;
1085
1086         pgste_set_unlock(ptep, new);
1087         pte_unmap_unlock(ptep, ptl);
1088         return 0;
1089 }
1090 EXPORT_SYMBOL(set_pgste_bits);
1091
1092 /**
1093  * get_pgste - get the current PGSTE for the given address.
1094  * @mm: the memory context. It must have PGSTEs, no check is performed here!
1095  * @hva: the host virtual address of the page whose PGSTE is to be processed
1096  * @pgstep: will be written with the current PGSTE for the given address.
1097  *
1098  * Return: 0 on success, < 0 in case of error.
1099  */
1100 int get_pgste(struct mm_struct *mm, unsigned long hva, unsigned long *pgstep)
1101 {
1102         spinlock_t *ptl;
1103         pte_t *ptep;
1104
1105         ptep = get_locked_pte(mm, hva, &ptl);
1106         if (unlikely(!ptep))
1107                 return -EFAULT;
1108         *pgstep = pgste_val(pgste_get(ptep));
1109         pte_unmap_unlock(ptep, ptl);
1110         return 0;
1111 }
1112 EXPORT_SYMBOL(get_pgste);
1113 #endif