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/tlb.h>
  23 #include <asm/tlbflush.h>
  24 #include <asm/mmu_context.h>
  25 #include <asm/page-states.h>
  26
  27 pgprot_t pgprot_writecombine(pgprot_t prot)
  28 {
  29         /*
  30          * mio_wb_bit_mask may be set on a different CPU, but it is only set
  31          * once at init and only read afterwards.
  32          */
  33         return __pgprot(pgprot_val(prot) | mio_wb_bit_mask);
  34 }
  35 EXPORT_SYMBOL_GPL(pgprot_writecombine);
  36
  37 pgprot_t pgprot_writethrough(pgprot_t prot)
  38 {
  39         /*
  40          * mio_wb_bit_mask may be set on a different CPU, but it is only set
  41          * once at init and only read afterwards.
  42          */
  43         return __pgprot(pgprot_val(prot) & ~mio_wb_bit_mask);
  44 }
  45 EXPORT_SYMBOL_GPL(pgprot_writethrough);
  46
  47 static inline void ptep_ipte_local(struct mm_struct *mm, unsigned long addr,
  48                                    pte_t *ptep, int nodat)
  49 {
  50         unsigned long opt, asce;
  51
  52         if (MACHINE_HAS_TLB_GUEST) {
  53                 opt = 0;
  54                 asce = READ_ONCE(mm->context.gmap_asce);
  55                 if (asce == 0UL || nodat)
  56                         opt |= IPTE_NODAT;
  57                 if (asce != -1UL) {
  58                         asce = asce ? : mm->context.asce;
  59                         opt |= IPTE_GUEST_ASCE;
  60                 }
  61                 __ptep_ipte(addr, ptep, opt, asce, IPTE_LOCAL);
  62         } else {
  63                 __ptep_ipte(addr, ptep, 0, 0, IPTE_LOCAL);
  64         }
  65 }
  66
  67 static inline void ptep_ipte_global(struct mm_struct *mm, unsigned long addr,
  68                                     pte_t *ptep, int nodat)
  69 {
  70         unsigned long opt, asce;
  71
  72         if (MACHINE_HAS_TLB_GUEST) {
  73                 opt = 0;
  74                 asce = READ_ONCE(mm->context.gmap_asce);
  75                 if (asce == 0UL || nodat)
  76                         opt |= IPTE_NODAT;
  77                 if (asce != -1UL) {
  78                         asce = asce ? : mm->context.asce;
  79                         opt |= IPTE_GUEST_ASCE;
  80                 }
  81                 __ptep_ipte(addr, ptep, opt, asce, IPTE_GLOBAL);
  82         } else {
  83                 __ptep_ipte(addr, ptep, 0, 0, IPTE_GLOBAL);
  84         }
  85 }
  86
  87 static inline pte_t ptep_flush_direct(struct mm_struct *mm,
  88                                       unsigned long addr, pte_t *ptep,
  89                                       int nodat)
  90 {
  91         pte_t old;
  92
  93         old = *ptep;
  94         if (unlikely(pte_val(old) & _PAGE_INVALID))
  95                 return old;
  96         atomic_inc(&mm->context.flush_count);
  97         if (MACHINE_HAS_TLB_LC &&
  98             cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
  99                 ptep_ipte_local(mm, addr, ptep, nodat);
 100         else
 101                 ptep_ipte_global(mm, addr, ptep, nodat);
 102         atomic_dec(&mm->context.flush_count);
 103         return old;
 104 }
 105
 106 static inline pte_t ptep_flush_lazy(struct mm_struct *mm,
 107                                     unsigned long addr, pte_t *ptep,
 108                                     int nodat)
 109 {
 110         pte_t old;
 111
 112         old = *ptep;
 113         if (unlikely(pte_val(old) & _PAGE_INVALID))
 114                 return old;
 115         atomic_inc(&mm->context.flush_count);
 116         if (cpumask_equal(&mm->context.cpu_attach_mask,
 117                           cpumask_of(smp_processor_id()))) {
 118                 pte_val(*ptep) |= _PAGE_INVALID;
 119                 mm->context.flush_mm = 1;
 120         } else
 121                 ptep_ipte_global(mm, addr, ptep, nodat);
 122         atomic_dec(&mm->context.flush_count);
 123         return old;
 124 }
 125
 126 static inline pgste_t pgste_get_lock(pte_t *ptep)
 127 {
 128         unsigned long new = 0;
 129 #ifdef CONFIG_PGSTE
 130         unsigned long old;
 131
 132         asm(
 133                 "       lg      %0,%2\n"
 134                 "0:     lgr     %1,%0\n"
 135                 "       nihh    %0,0xff7f\n"    /* clear PCL bit in old */
 136                 "       oihh    %1,0x0080\n"    /* set PCL bit in new */
 137                 "       csg     %0,%1,%2\n"
 138                 "       jl      0b\n"
 139                 : "=&d" (old), "=&d" (new), "=Q" (ptep[PTRS_PER_PTE])
 140                 : "Q" (ptep[PTRS_PER_PTE]) : "cc", "memory");
 141 #endif
 142         return __pgste(new);
 143 }
 144
 145 static inline void pgste_set_unlock(pte_t *ptep, pgste_t pgste)
 146 {
 147 #ifdef CONFIG_PGSTE
 148         asm(
 149                 "       nihh    %1,0xff7f\n"    /* clear PCL bit */
 150                 "       stg     %1,%0\n"
 151                 : "=Q" (ptep[PTRS_PER_PTE])
 152                 : "d" (pgste_val(pgste)), "Q" (ptep[PTRS_PER_PTE])
 153                 : "cc", "memory");
 154 #endif
 155 }
 156
 157 static inline pgste_t pgste_get(pte_t *ptep)
 158 {
 159         unsigned long pgste = 0;
 160 #ifdef CONFIG_PGSTE
 161         pgste = *(unsigned long *)(ptep + PTRS_PER_PTE);
 162 #endif
 163         return __pgste(pgste);
 164 }
 165
 166 static inline void pgste_set(pte_t *ptep, pgste_t pgste)
 167 {
 168 #ifdef CONFIG_PGSTE
 169         *(pgste_t *)(ptep + PTRS_PER_PTE) = pgste;
 170 #endif
 171 }
 172
 173 static inline pgste_t pgste_update_all(pte_t pte, pgste_t pgste,
 174                                        struct mm_struct *mm)
 175 {
 176 #ifdef CONFIG_PGSTE
 177         unsigned long address, bits, skey;
 178
 179         if (!mm_uses_skeys(mm) || pte_val(pte) & _PAGE_INVALID)
 180                 return pgste;
 181         address = pte_val(pte) & PAGE_MASK;
 182         skey = (unsigned long) page_get_storage_key(address);
 183         bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED);
 184         /* Transfer page changed & referenced bit to guest bits in pgste */
 185         pgste_val(pgste) |= bits << 48;         /* GR bit & GC bit */
 186         /* Copy page access key and fetch protection bit to pgste */
 187         pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT);
 188         pgste_val(pgste) |= (skey & (_PAGE_ACC_BITS | _PAGE_FP_BIT)) << 56;
 189 #endif
 190         return pgste;
 191
 192 }
 193
 194 static inline void pgste_set_key(pte_t *ptep, pgste_t pgste, pte_t entry,
 195                                  struct mm_struct *mm)
 196 {
 197 #ifdef CONFIG_PGSTE
 198         unsigned long address;
 199         unsigned long nkey;
 200
 201         if (!mm_uses_skeys(mm) || pte_val(entry) & _PAGE_INVALID)
 202                 return;
 203         VM_BUG_ON(!(pte_val(*ptep) & _PAGE_INVALID));
 204         address = pte_val(entry) & PAGE_MASK;
 205         /*
 206          * Set page access key and fetch protection bit from pgste.
 207          * The guest C/R information is still in the PGSTE, set real
 208          * key C/R to 0.
 209          */
 210         nkey = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
 211         nkey |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48;
 212         page_set_storage_key(address, nkey, 0);
 213 #endif
 214 }
 215
 216 static inline pgste_t pgste_set_pte(pte_t *ptep, pgste_t pgste, pte_t entry)
 217 {
 218 #ifdef CONFIG_PGSTE
 219         if ((pte_val(entry) & _PAGE_PRESENT) &&
 220             (pte_val(entry) & _PAGE_WRITE) &&
 221             !(pte_val(entry) & _PAGE_INVALID)) {
 222                 if (!MACHINE_HAS_ESOP) {
 223                         /*
 224                          * Without enhanced suppression-on-protection force
 225                          * the dirty bit on for all writable ptes.
 226                          */
 227                         pte_val(entry) |= _PAGE_DIRTY;
 228                         pte_val(entry) &= ~_PAGE_PROTECT;
 229                 }
 230                 if (!(pte_val(entry) & _PAGE_PROTECT))
 231                         /* This pte allows write access, set user-dirty */
 232                         pgste_val(pgste) |= PGSTE_UC_BIT;
 233         }
 234 #endif
 235         *ptep = entry;
 236         return pgste;
 237 }
 238
 239 static inline pgste_t pgste_pte_notify(struct mm_struct *mm,
 240                                        unsigned long addr,
 241                                        pte_t *ptep, pgste_t pgste)
 242 {
 243 #ifdef CONFIG_PGSTE
 244         unsigned long bits;
 245
 246         bits = pgste_val(pgste) & (PGSTE_IN_BIT | PGSTE_VSIE_BIT);
 247         if (bits) {
 248                 pgste_val(pgste) ^= bits;
 249                 ptep_notify(mm, addr, ptep, bits);
 250         }
 251 #endif
 252         return pgste;
 253 }
 254
 255 static inline pgste_t ptep_xchg_start(struct mm_struct *mm,
 256                                       unsigned long addr, pte_t *ptep)
 257 {
 258         pgste_t pgste = __pgste(0);
 259
 260         if (mm_has_pgste(mm)) {
 261                 pgste = pgste_get_lock(ptep);
 262                 pgste = pgste_pte_notify(mm, addr, ptep, pgste);
 263         }
 264         return pgste;
 265 }
 266
 267 static inline pte_t ptep_xchg_commit(struct mm_struct *mm,
 268                                     unsigned long addr, pte_t *ptep,
 269                                     pgste_t pgste, pte_t old, pte_t new)
 270 {
 271         if (mm_has_pgste(mm)) {
 272                 if (pte_val(old) & _PAGE_INVALID)
 273                         pgste_set_key(ptep, pgste, new, mm);
 274                 if (pte_val(new) & _PAGE_INVALID) {
 275                         pgste = pgste_update_all(old, pgste, mm);
 276                         if ((pgste_val(pgste) & _PGSTE_GPS_USAGE_MASK) ==
 277                             _PGSTE_GPS_USAGE_UNUSED)
 278                                 pte_val(old) |= _PAGE_UNUSED;
 279                 }
 280                 pgste = pgste_set_pte(ptep, pgste, new);
 281                 pgste_set_unlock(ptep, pgste);
 282         } else {
 283                 *ptep = new;
 284         }
 285         return old;
 286 }
 287
 288 pte_t ptep_xchg_direct(struct mm_struct *mm, unsigned long addr,
 289                        pte_t *ptep, pte_t new)
 290 {
 291         pgste_t pgste;
 292         pte_t old;
 293         int nodat;
 294
 295         preempt_disable();
 296         pgste = ptep_xchg_start(mm, addr, ptep);
 297         nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 298         old = ptep_flush_direct(mm, addr, ptep, nodat);
 299         old = ptep_xchg_commit(mm, addr, ptep, pgste, old, new);
 300         preempt_enable();
 301         return old;
 302 }
 303 EXPORT_SYMBOL(ptep_xchg_direct);
 304
 305 pte_t ptep_xchg_lazy(struct mm_struct *mm, unsigned long addr,
 306                      pte_t *ptep, pte_t new)
 307 {
 308         pgste_t pgste;
 309         pte_t old;
 310         int nodat;
 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         old = ptep_xchg_commit(mm, addr, ptep, pgste, old, new);
 317         preempt_enable();
 318         return old;
 319 }
 320 EXPORT_SYMBOL(ptep_xchg_lazy);
 321
 322 pte_t ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr,
 323                              pte_t *ptep)
 324 {
 325         pgste_t pgste;
 326         pte_t old;
 327         int nodat;
 328         struct mm_struct *mm = vma->vm_mm;
 329
 330         preempt_disable();
 331         pgste = ptep_xchg_start(mm, addr, ptep);
 332         nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 333         old = ptep_flush_lazy(mm, addr, ptep, nodat);
 334         if (mm_has_pgste(mm)) {
 335                 pgste = pgste_update_all(old, pgste, mm);
 336                 pgste_set(ptep, pgste);
 337         }
 338         return old;
 339 }
 340
 341 void ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr,
 342                              pte_t *ptep, pte_t old_pte, pte_t pte)
 343 {
 344         pgste_t pgste;
 345         struct mm_struct *mm = vma->vm_mm;
 346
 347         if (!MACHINE_HAS_NX)
 348                 pte_val(pte) &= ~_PAGE_NOEXEC;
 349         if (mm_has_pgste(mm)) {
 350                 pgste = pgste_get(ptep);
 351                 pgste_set_key(ptep, pgste, pte, mm);
 352                 pgste = pgste_set_pte(ptep, pgste, pte);
 353                 pgste_set_unlock(ptep, pgste);
 354         } else {
 355                 *ptep = pte;
 356         }
 357         preempt_enable();
 358 }
 359
 360 static inline void pmdp_idte_local(struct mm_struct *mm,
 361                                    unsigned long addr, pmd_t *pmdp)
 362 {
 363         if (MACHINE_HAS_TLB_GUEST)
 364                 __pmdp_idte(addr, pmdp, IDTE_NODAT | IDTE_GUEST_ASCE,
 365                             mm->context.asce, IDTE_LOCAL);
 366         else
 367                 __pmdp_idte(addr, pmdp, 0, 0, IDTE_LOCAL);
 368         if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)
 369                 gmap_pmdp_idte_local(mm, addr);
 370 }
 371
 372 static inline void pmdp_idte_global(struct mm_struct *mm,
 373                                     unsigned long addr, pmd_t *pmdp)
 374 {
 375         if (MACHINE_HAS_TLB_GUEST) {
 376                 __pmdp_idte(addr, pmdp, IDTE_NODAT | IDTE_GUEST_ASCE,
 377                             mm->context.asce, IDTE_GLOBAL);
 378                 if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)
 379                         gmap_pmdp_idte_global(mm, addr);
 380         } else if (MACHINE_HAS_IDTE) {
 381                 __pmdp_idte(addr, pmdp, 0, 0, IDTE_GLOBAL);
 382                 if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)
 383                         gmap_pmdp_idte_global(mm, addr);
 384         } else {
 385                 __pmdp_csp(pmdp);
 386                 if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)
 387                         gmap_pmdp_csp(mm, addr);
 388         }
 389 }
 390
 391 static inline pmd_t pmdp_flush_direct(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 (MACHINE_HAS_TLB_LC &&
 401             cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
 402                 pmdp_idte_local(mm, addr, pmdp);
 403         else
 404                 pmdp_idte_global(mm, addr, pmdp);
 405         atomic_dec(&mm->context.flush_count);
 406         return old;
 407 }
 408
 409 static inline pmd_t pmdp_flush_lazy(struct mm_struct *mm,
 410                                     unsigned long addr, pmd_t *pmdp)
 411 {
 412         pmd_t old;
 413
 414         old = *pmdp;
 415         if (pmd_val(old) & _SEGMENT_ENTRY_INVALID)
 416                 return old;
 417         atomic_inc(&mm->context.flush_count);
 418         if (cpumask_equal(&mm->context.cpu_attach_mask,
 419                           cpumask_of(smp_processor_id()))) {
 420                 pmd_val(*pmdp) |= _SEGMENT_ENTRY_INVALID;
 421                 mm->context.flush_mm = 1;
 422                 if (mm_has_pgste(mm))
 423                         gmap_pmdp_invalidate(mm, addr);
 424         } else {
 425                 pmdp_idte_global(mm, addr, pmdp);
 426         }
 427         atomic_dec(&mm->context.flush_count);
 428         return old;
 429 }
 430
 431 #ifdef CONFIG_PGSTE
 432 static pmd_t *pmd_alloc_map(struct mm_struct *mm, unsigned long addr)
 433 {
 434         pgd_t *pgd;
 435         p4d_t *p4d;
 436         pud_t *pud;
 437         pmd_t *pmd;
 438
 439         pgd = pgd_offset(mm, addr);
 440         p4d = p4d_alloc(mm, pgd, addr);
 441         if (!p4d)
 442                 return NULL;
 443         pud = pud_alloc(mm, p4d, addr);
 444         if (!pud)
 445                 return NULL;
 446         pmd = pmd_alloc(mm, pud, addr);
 447         return pmd;
 448 }
 449 #endif
 450
 451 pmd_t pmdp_xchg_direct(struct mm_struct *mm, unsigned long addr,
 452                        pmd_t *pmdp, pmd_t new)
 453 {
 454         pmd_t old;
 455
 456         preempt_disable();
 457         old = pmdp_flush_direct(mm, addr, pmdp);
 458         *pmdp = new;
 459         preempt_enable();
 460         return old;
 461 }
 462 EXPORT_SYMBOL(pmdp_xchg_direct);
 463
 464 pmd_t pmdp_xchg_lazy(struct mm_struct *mm, unsigned long addr,
 465                      pmd_t *pmdp, pmd_t new)
 466 {
 467         pmd_t old;
 468
 469         preempt_disable();
 470         old = pmdp_flush_lazy(mm, addr, pmdp);
 471         *pmdp = new;
 472         preempt_enable();
 473         return old;
 474 }
 475 EXPORT_SYMBOL(pmdp_xchg_lazy);
 476
 477 static inline void pudp_idte_local(struct mm_struct *mm,
 478                                    unsigned long addr, pud_t *pudp)
 479 {
 480         if (MACHINE_HAS_TLB_GUEST)
 481                 __pudp_idte(addr, pudp, IDTE_NODAT | IDTE_GUEST_ASCE,
 482                             mm->context.asce, IDTE_LOCAL);
 483         else
 484                 __pudp_idte(addr, pudp, 0, 0, IDTE_LOCAL);
 485 }
 486
 487 static inline void pudp_idte_global(struct mm_struct *mm,
 488                                     unsigned long addr, pud_t *pudp)
 489 {
 490         if (MACHINE_HAS_TLB_GUEST)
 491                 __pudp_idte(addr, pudp, IDTE_NODAT | IDTE_GUEST_ASCE,
 492                             mm->context.asce, IDTE_GLOBAL);
 493         else if (MACHINE_HAS_IDTE)
 494                 __pudp_idte(addr, pudp, 0, 0, IDTE_GLOBAL);
 495         else
 496                 /*
 497                  * Invalid bit position is the same for pmd and pud, so we can
 498                  * re-use _pmd_csp() here
 499                  */
 500                 __pmdp_csp((pmd_t *) pudp);
 501 }
 502
 503 static inline pud_t pudp_flush_direct(struct mm_struct *mm,
 504                                       unsigned long addr, pud_t *pudp)
 505 {
 506         pud_t old;
 507
 508         old = *pudp;
 509         if (pud_val(old) & _REGION_ENTRY_INVALID)
 510                 return old;
 511         atomic_inc(&mm->context.flush_count);
 512         if (MACHINE_HAS_TLB_LC &&
 513             cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
 514                 pudp_idte_local(mm, addr, pudp);
 515         else
 516                 pudp_idte_global(mm, addr, pudp);
 517         atomic_dec(&mm->context.flush_count);
 518         return old;
 519 }
 520
 521 pud_t pudp_xchg_direct(struct mm_struct *mm, unsigned long addr,
 522                        pud_t *pudp, pud_t new)
 523 {
 524         pud_t old;
 525
 526         preempt_disable();
 527         old = pudp_flush_direct(mm, addr, pudp);
 528         *pudp = new;
 529         preempt_enable();
 530         return old;
 531 }
 532 EXPORT_SYMBOL(pudp_xchg_direct);
 533
 534 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 535 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 536                                 pgtable_t pgtable)
 537 {
 538         struct list_head *lh = (struct list_head *) pgtable;
 539
 540         assert_spin_locked(pmd_lockptr(mm, pmdp));
 541
 542         /* FIFO */
 543         if (!pmd_huge_pte(mm, pmdp))
 544                 INIT_LIST_HEAD(lh);
 545         else
 546                 list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
 547         pmd_huge_pte(mm, pmdp) = pgtable;
 548 }
 549
 550 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 551 {
 552         struct list_head *lh;
 553         pgtable_t pgtable;
 554         pte_t *ptep;
 555
 556         assert_spin_locked(pmd_lockptr(mm, pmdp));
 557
 558         /* FIFO */
 559         pgtable = pmd_huge_pte(mm, pmdp);
 560         lh = (struct list_head *) pgtable;
 561         if (list_empty(lh))
 562                 pmd_huge_pte(mm, pmdp) = NULL;
 563         else {
 564                 pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
 565                 list_del(lh);
 566         }
 567         ptep = (pte_t *) pgtable;
 568         pte_val(*ptep) = _PAGE_INVALID;
 569         ptep++;
 570         pte_val(*ptep) = _PAGE_INVALID;
 571         return pgtable;
 572 }
 573 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 574
 575 #ifdef CONFIG_PGSTE
 576 void ptep_set_pte_at(struct mm_struct *mm, unsigned long addr,
 577                      pte_t *ptep, pte_t entry)
 578 {
 579         pgste_t pgste;
 580
 581         /* the mm_has_pgste() check is done in set_pte_at() */
 582         preempt_disable();
 583         pgste = pgste_get_lock(ptep);
 584         pgste_val(pgste) &= ~_PGSTE_GPS_ZERO;
 585         pgste_set_key(ptep, pgste, entry, mm);
 586         pgste = pgste_set_pte(ptep, pgste, entry);
 587         pgste_set_unlock(ptep, pgste);
 588         preempt_enable();
 589 }
 590
 591 void ptep_set_notify(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 592 {
 593         pgste_t pgste;
 594
 595         preempt_disable();
 596         pgste = pgste_get_lock(ptep);
 597         pgste_val(pgste) |= PGSTE_IN_BIT;
 598         pgste_set_unlock(ptep, pgste);
 599         preempt_enable();
 600 }
 601
 602 /**
 603  * ptep_force_prot - change access rights of a locked pte
 604  * @mm: pointer to the process mm_struct
 605  * @addr: virtual address in the guest address space
 606  * @ptep: pointer to the page table entry
 607  * @prot: indicates guest access rights: PROT_NONE, PROT_READ or PROT_WRITE
 608  * @bit: pgste bit to set (e.g. for notification)
 609  *
 610  * Returns 0 if the access rights were changed and -EAGAIN if the current
 611  * and requested access rights are incompatible.
 612  */
 613 int ptep_force_prot(struct mm_struct *mm, unsigned long addr,
 614                     pte_t *ptep, int prot, unsigned long bit)
 615 {
 616         pte_t entry;
 617         pgste_t pgste;
 618         int pte_i, pte_p, nodat;
 619
 620         pgste = pgste_get_lock(ptep);
 621         entry = *ptep;
 622         /* Check pte entry after all locks have been acquired */
 623         pte_i = pte_val(entry) & _PAGE_INVALID;
 624         pte_p = pte_val(entry) & _PAGE_PROTECT;
 625         if ((pte_i && (prot != PROT_NONE)) ||
 626             (pte_p && (prot & PROT_WRITE))) {
 627                 pgste_set_unlock(ptep, pgste);
 628                 return -EAGAIN;
 629         }
 630         /* Change access rights and set pgste bit */
 631         nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 632         if (prot == PROT_NONE && !pte_i) {
 633                 ptep_flush_direct(mm, addr, ptep, nodat);
 634                 pgste = pgste_update_all(entry, pgste, mm);
 635                 pte_val(entry) |= _PAGE_INVALID;
 636         }
 637         if (prot == PROT_READ && !pte_p) {
 638                 ptep_flush_direct(mm, addr, ptep, nodat);
 639                 pte_val(entry) &= ~_PAGE_INVALID;
 640                 pte_val(entry) |= _PAGE_PROTECT;
 641         }
 642         pgste_val(pgste) |= bit;
 643         pgste = pgste_set_pte(ptep, pgste, entry);
 644         pgste_set_unlock(ptep, pgste);
 645         return 0;
 646 }
 647
 648 int ptep_shadow_pte(struct mm_struct *mm, unsigned long saddr,
 649                     pte_t *sptep, pte_t *tptep, pte_t pte)
 650 {
 651         pgste_t spgste, tpgste;
 652         pte_t spte, tpte;
 653         int rc = -EAGAIN;
 654
 655         if (!(pte_val(*tptep) & _PAGE_INVALID))
 656                 return 0;       /* already shadowed */
 657         spgste = pgste_get_lock(sptep);
 658         spte = *sptep;
 659         if (!(pte_val(spte) & _PAGE_INVALID) &&
 660             !((pte_val(spte) & _PAGE_PROTECT) &&
 661               !(pte_val(pte) & _PAGE_PROTECT))) {
 662                 pgste_val(spgste) |= PGSTE_VSIE_BIT;
 663                 tpgste = pgste_get_lock(tptep);
 664                 pte_val(tpte) = (pte_val(spte) & PAGE_MASK) |
 665                                 (pte_val(pte) & _PAGE_PROTECT);
 666                 /* don't touch the storage key - it belongs to parent pgste */
 667                 tpgste = pgste_set_pte(tptep, tpgste, tpte);
 668                 pgste_set_unlock(tptep, tpgste);
 669                 rc = 1;
 670         }
 671         pgste_set_unlock(sptep, spgste);
 672         return rc;
 673 }
 674
 675 void ptep_unshadow_pte(struct mm_struct *mm, unsigned long saddr, pte_t *ptep)
 676 {
 677         pgste_t pgste;
 678         int nodat;
 679
 680         pgste = pgste_get_lock(ptep);
 681         /* notifier is called by the caller */
 682         nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 683         ptep_flush_direct(mm, saddr, ptep, nodat);
 684         /* don't touch the storage key - it belongs to parent pgste */
 685         pgste = pgste_set_pte(ptep, pgste, __pte(_PAGE_INVALID));
 686         pgste_set_unlock(ptep, pgste);
 687 }
 688
 689 static void ptep_zap_swap_entry(struct mm_struct *mm, swp_entry_t entry)
 690 {
 691         if (!non_swap_entry(entry))
 692                 dec_mm_counter(mm, MM_SWAPENTS);
 693         else if (is_migration_entry(entry)) {
 694                 struct page *page = migration_entry_to_page(entry);
 695
 696                 dec_mm_counter(mm, mm_counter(page));
 697         }
 698         free_swap_and_cache(entry);
 699 }
 700
 701 void ptep_zap_unused(struct mm_struct *mm, unsigned long addr,
 702                      pte_t *ptep, int reset)
 703 {
 704         unsigned long pgstev;
 705         pgste_t pgste;
 706         pte_t pte;
 707
 708         /* Zap unused and logically-zero pages */
 709         preempt_disable();
 710         pgste = pgste_get_lock(ptep);
 711         pgstev = pgste_val(pgste);
 712         pte = *ptep;
 713         if (!reset && pte_swap(pte) &&
 714             ((pgstev & _PGSTE_GPS_USAGE_MASK) == _PGSTE_GPS_USAGE_UNUSED ||
 715              (pgstev & _PGSTE_GPS_ZERO))) {
 716                 ptep_zap_swap_entry(mm, pte_to_swp_entry(pte));
 717                 pte_clear(mm, addr, ptep);
 718         }
 719         if (reset)
 720                 pgste_val(pgste) &= ~_PGSTE_GPS_USAGE_MASK;
 721         pgste_set_unlock(ptep, pgste);
 722         preempt_enable();
 723 }
 724
 725 void ptep_zap_key(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 726 {
 727         unsigned long ptev;
 728         pgste_t pgste;
 729
 730         /* Clear storage key ACC and F, but set R/C */
 731         preempt_disable();
 732         pgste = pgste_get_lock(ptep);
 733         pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT);
 734         pgste_val(pgste) |= PGSTE_GR_BIT | PGSTE_GC_BIT;
 735         ptev = pte_val(*ptep);
 736         if (!(ptev & _PAGE_INVALID) && (ptev & _PAGE_WRITE))
 737                 page_set_storage_key(ptev & PAGE_MASK, PAGE_DEFAULT_KEY, 1);
 738         pgste_set_unlock(ptep, pgste);
 739         preempt_enable();
 740 }
 741
 742 /*
 743  * Test and reset if a guest page is dirty
 744  */
 745 bool ptep_test_and_clear_uc(struct mm_struct *mm, unsigned long addr,
 746                        pte_t *ptep)
 747 {
 748         pgste_t pgste;
 749         pte_t pte;
 750         bool dirty;
 751         int nodat;
 752
 753         pgste = pgste_get_lock(ptep);
 754         dirty = !!(pgste_val(pgste) & PGSTE_UC_BIT);
 755         pgste_val(pgste) &= ~PGSTE_UC_BIT;
 756         pte = *ptep;
 757         if (dirty && (pte_val(pte) & _PAGE_PRESENT)) {
 758                 pgste = pgste_pte_notify(mm, addr, ptep, pgste);
 759                 nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 760                 ptep_ipte_global(mm, addr, ptep, nodat);
 761                 if (MACHINE_HAS_ESOP || !(pte_val(pte) & _PAGE_WRITE))
 762                         pte_val(pte) |= _PAGE_PROTECT;
 763                 else
 764                         pte_val(pte) |= _PAGE_INVALID;
 765                 *ptep = pte;
 766         }
 767         pgste_set_unlock(ptep, pgste);
 768         return dirty;
 769 }
 770 EXPORT_SYMBOL_GPL(ptep_test_and_clear_uc);
 771
 772 int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 773                           unsigned char key, bool nq)
 774 {
 775         unsigned long keyul, paddr;
 776         spinlock_t *ptl;
 777         pgste_t old, new;
 778         pmd_t *pmdp;
 779         pte_t *ptep;
 780
 781         pmdp = pmd_alloc_map(mm, addr);
 782         if (unlikely(!pmdp))
 783                 return -EFAULT;
 784
 785         ptl = pmd_lock(mm, pmdp);
 786         if (!pmd_present(*pmdp)) {
 787                 spin_unlock(ptl);
 788                 return -EFAULT;
 789         }
 790
 791         if (pmd_large(*pmdp)) {
 792                 paddr = pmd_val(*pmdp) & HPAGE_MASK;
 793                 paddr |= addr & ~HPAGE_MASK;
 794                 /*
 795                  * Huge pmds need quiescing operations, they are
 796                  * always mapped.
 797                  */
 798                 page_set_storage_key(paddr, key, 1);
 799                 spin_unlock(ptl);
 800                 return 0;
 801         }
 802         spin_unlock(ptl);
 803
 804         ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
 805         if (unlikely(!ptep))
 806                 return -EFAULT;
 807
 808         new = old = pgste_get_lock(ptep);
 809         pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT |
 810                             PGSTE_ACC_BITS | PGSTE_FP_BIT);
 811         keyul = (unsigned long) key;
 812         pgste_val(new) |= (keyul & (_PAGE_CHANGED | _PAGE_REFERENCED)) << 48;
 813         pgste_val(new) |= (keyul & (_PAGE_ACC_BITS | _PAGE_FP_BIT)) << 56;
 814         if (!(pte_val(*ptep) & _PAGE_INVALID)) {
 815                 unsigned long bits, skey;
 816
 817                 paddr = pte_val(*ptep) & PAGE_MASK;
 818                 skey = (unsigned long) page_get_storage_key(paddr);
 819                 bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED);
 820                 skey = key & (_PAGE_ACC_BITS | _PAGE_FP_BIT);
 821                 /* Set storage key ACC and FP */
 822                 page_set_storage_key(paddr, skey, !nq);
 823                 /* Merge host changed & referenced into pgste  */
 824                 pgste_val(new) |= bits << 52;
 825         }
 826         /* changing the guest storage key is considered a change of the page */
 827         if ((pgste_val(new) ^ pgste_val(old)) &
 828             (PGSTE_ACC_BITS | PGSTE_FP_BIT | PGSTE_GR_BIT | PGSTE_GC_BIT))
 829                 pgste_val(new) |= PGSTE_UC_BIT;
 830
 831         pgste_set_unlock(ptep, new);
 832         pte_unmap_unlock(ptep, ptl);
 833         return 0;
 834 }
 835 EXPORT_SYMBOL(set_guest_storage_key);
 836
 837 /**
 838  * Conditionally set a guest storage key (handling csske).
 839  * oldkey will be updated when either mr or mc is set and a pointer is given.
 840  *
 841  * Returns 0 if a guests storage key update wasn't necessary, 1 if the guest
 842  * storage key was updated and -EFAULT on access errors.
 843  */
 844 int cond_set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 845                                unsigned char key, unsigned char *oldkey,
 846                                bool nq, bool mr, bool mc)
 847 {
 848         unsigned char tmp, mask = _PAGE_ACC_BITS | _PAGE_FP_BIT;
 849         int rc;
 850
 851         /* we can drop the pgste lock between getting and setting the key */
 852         if (mr | mc) {
 853                 rc = get_guest_storage_key(current->mm, addr, &tmp);
 854                 if (rc)
 855                         return rc;
 856                 if (oldkey)
 857                         *oldkey = tmp;
 858                 if (!mr)
 859                         mask |= _PAGE_REFERENCED;
 860                 if (!mc)
 861                         mask |= _PAGE_CHANGED;
 862                 if (!((tmp ^ key) & mask))
 863                         return 0;
 864         }
 865         rc = set_guest_storage_key(current->mm, addr, key, nq);
 866         return rc < 0 ? rc : 1;
 867 }
 868 EXPORT_SYMBOL(cond_set_guest_storage_key);
 869
 870 /**
 871  * Reset a guest reference bit (rrbe), returning the reference and changed bit.
 872  *
 873  * Returns < 0 in case of error, otherwise the cc to be reported to the guest.
 874  */
 875 int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr)
 876 {
 877         spinlock_t *ptl;
 878         unsigned long paddr;
 879         pgste_t old, new;
 880         pmd_t *pmdp;
 881         pte_t *ptep;
 882         int cc = 0;
 883
 884         pmdp = pmd_alloc_map(mm, addr);
 885         if (unlikely(!pmdp))
 886                 return -EFAULT;
 887
 888         ptl = pmd_lock(mm, pmdp);
 889         if (!pmd_present(*pmdp)) {
 890                 spin_unlock(ptl);
 891                 return -EFAULT;
 892         }
 893
 894         if (pmd_large(*pmdp)) {
 895                 paddr = pmd_val(*pmdp) & HPAGE_MASK;
 896                 paddr |= addr & ~HPAGE_MASK;
 897                 cc = page_reset_referenced(paddr);
 898                 spin_unlock(ptl);
 899                 return cc;
 900         }
 901         spin_unlock(ptl);
 902
 903         ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
 904         if (unlikely(!ptep))
 905                 return -EFAULT;
 906
 907         new = old = pgste_get_lock(ptep);
 908         /* Reset guest reference bit only */
 909         pgste_val(new) &= ~PGSTE_GR_BIT;
 910
 911         if (!(pte_val(*ptep) & _PAGE_INVALID)) {
 912                 paddr = pte_val(*ptep) & PAGE_MASK;
 913                 cc = page_reset_referenced(paddr);
 914                 /* Merge real referenced bit into host-set */
 915                 pgste_val(new) |= ((unsigned long) cc << 53) & PGSTE_HR_BIT;
 916         }
 917         /* Reflect guest's logical view, not physical */
 918         cc |= (pgste_val(old) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 49;
 919         /* Changing the guest storage key is considered a change of the page */
 920         if ((pgste_val(new) ^ pgste_val(old)) & PGSTE_GR_BIT)
 921                 pgste_val(new) |= PGSTE_UC_BIT;
 922
 923         pgste_set_unlock(ptep, new);
 924         pte_unmap_unlock(ptep, ptl);
 925         return cc;
 926 }
 927 EXPORT_SYMBOL(reset_guest_reference_bit);
 928
 929 int get_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 930                           unsigned char *key)
 931 {
 932         unsigned long paddr;
 933         spinlock_t *ptl;
 934         pgste_t pgste;
 935         pmd_t *pmdp;
 936         pte_t *ptep;
 937
 938         pmdp = pmd_alloc_map(mm, addr);
 939         if (unlikely(!pmdp))
 940                 return -EFAULT;
 941
 942         ptl = pmd_lock(mm, pmdp);
 943         if (!pmd_present(*pmdp)) {
 944                 /* Not yet mapped memory has a zero key */
 945                 spin_unlock(ptl);
 946                 *key = 0;
 947                 return 0;
 948         }
 949
 950         if (pmd_large(*pmdp)) {
 951                 paddr = pmd_val(*pmdp) & HPAGE_MASK;
 952                 paddr |= addr & ~HPAGE_MASK;
 953                 *key = page_get_storage_key(paddr);
 954                 spin_unlock(ptl);
 955                 return 0;
 956         }
 957         spin_unlock(ptl);
 958
 959         ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
 960         if (unlikely(!ptep))
 961                 return -EFAULT;
 962
 963         pgste = pgste_get_lock(ptep);
 964         *key = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
 965         paddr = pte_val(*ptep) & PAGE_MASK;
 966         if (!(pte_val(*ptep) & _PAGE_INVALID))
 967                 *key = page_get_storage_key(paddr);
 968         /* Reflect guest's logical view, not physical */
 969         *key |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48;
 970         pgste_set_unlock(ptep, pgste);
 971         pte_unmap_unlock(ptep, ptl);
 972         return 0;
 973 }
 974 EXPORT_SYMBOL(get_guest_storage_key);
 975
 976 /**
 977  * pgste_perform_essa - perform ESSA actions on the PGSTE.
 978  * @mm: the memory context. It must have PGSTEs, no check is performed here!
 979  * @hva: the host virtual address of the page whose PGSTE is to be processed
 980  * @orc: the specific action to perform, see the ESSA_SET_* macros.
 981  * @oldpte: the PTE will be saved there if the pointer is not NULL.
 982  * @oldpgste: the old PGSTE will be saved there if the pointer is not NULL.
 983  *
 984  * Return: 1 if the page is to be added to the CBRL, otherwise 0,
 985  *         or < 0 in case of error. -EINVAL is returned for invalid values
 986  *         of orc, -EFAULT for invalid addresses.
 987  */
 988 int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc,
 989                         unsigned long *oldpte, unsigned long *oldpgste)
 990 {
 991         unsigned long pgstev;
 992         spinlock_t *ptl;
 993         pgste_t pgste;
 994         pte_t *ptep;
 995         int res = 0;
 996
 997         WARN_ON_ONCE(orc > ESSA_MAX);
 998         if (unlikely(orc > ESSA_MAX))
 999                 return -EINVAL;
1000         ptep = get_locked_pte(mm, hva, &ptl);
1001         if (unlikely(!ptep))
1002                 return -EFAULT;
1003         pgste = pgste_get_lock(ptep);
1004         pgstev = pgste_val(pgste);
1005         if (oldpte)
1006                 *oldpte = pte_val(*ptep);
1007         if (oldpgste)
1008                 *oldpgste = pgstev;
1009
1010         switch (orc) {
1011         case ESSA_GET_STATE:
1012                 break;
1013         case ESSA_SET_STABLE:
1014                 pgstev &= ~(_PGSTE_GPS_USAGE_MASK | _PGSTE_GPS_NODAT);
1015                 pgstev |= _PGSTE_GPS_USAGE_STABLE;
1016                 break;
1017         case ESSA_SET_UNUSED:
1018                 pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1019                 pgstev |= _PGSTE_GPS_USAGE_UNUSED;
1020                 if (pte_val(*ptep) & _PAGE_INVALID)
1021                         res = 1;
1022                 break;
1023         case ESSA_SET_VOLATILE:
1024                 pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1025                 pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
1026                 if (pte_val(*ptep) & _PAGE_INVALID)
1027                         res = 1;
1028                 break;
1029         case ESSA_SET_POT_VOLATILE:
1030                 pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1031                 if (!(pte_val(*ptep) & _PAGE_INVALID)) {
1032                         pgstev |= _PGSTE_GPS_USAGE_POT_VOLATILE;
1033                         break;
1034                 }
1035                 if (pgstev & _PGSTE_GPS_ZERO) {
1036                         pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
1037                         break;
1038                 }
1039                 if (!(pgstev & PGSTE_GC_BIT)) {
1040                         pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
1041                         res = 1;
1042                         break;
1043                 }
1044                 break;
1045         case ESSA_SET_STABLE_RESIDENT:
1046                 pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1047                 pgstev |= _PGSTE_GPS_USAGE_STABLE;
1048                 /*
1049                  * Since the resident state can go away any time after this
1050                  * call, we will not make this page resident. We can revisit
1051                  * this decision if a guest will ever start using this.
1052                  */
1053                 break;
1054         case ESSA_SET_STABLE_IF_RESIDENT:
1055                 if (!(pte_val(*ptep) & _PAGE_INVALID)) {
1056                         pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1057                         pgstev |= _PGSTE_GPS_USAGE_STABLE;
1058                 }
1059                 break;
1060         case ESSA_SET_STABLE_NODAT:
1061                 pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1062                 pgstev |= _PGSTE_GPS_USAGE_STABLE | _PGSTE_GPS_NODAT;
1063                 break;
1064         default:
1065                 /* we should never get here! */
1066                 break;
1067         }
1068         /* If we are discarding a page, set it to logical zero */
1069         if (res)
1070                 pgstev |= _PGSTE_GPS_ZERO;
1071
1072         pgste_val(pgste) = pgstev;
1073         pgste_set_unlock(ptep, pgste);
1074         pte_unmap_unlock(ptep, ptl);
1075         return res;
1076 }
1077 EXPORT_SYMBOL(pgste_perform_essa);
1078
1079 /**
1080  * set_pgste_bits - set specific PGSTE bits.
1081  * @mm: the memory context. It must have PGSTEs, no check is performed here!
1082  * @hva: the host virtual address of the page whose PGSTE is to be processed
1083  * @bits: a bitmask representing the bits that will be touched
1084  * @value: the values of the bits to be written. Only the bits in the mask
1085  *         will be written.
1086  *
1087  * Return: 0 on success, < 0 in case of error.
1088  */
1089 int set_pgste_bits(struct mm_struct *mm, unsigned long hva,
1090                         unsigned long bits, unsigned long value)
1091 {
1092         spinlock_t *ptl;
1093         pgste_t new;
1094         pte_t *ptep;
1095
1096         ptep = get_locked_pte(mm, hva, &ptl);
1097         if (unlikely(!ptep))
1098                 return -EFAULT;
1099         new = pgste_get_lock(ptep);
1100
1101         pgste_val(new) &= ~bits;
1102         pgste_val(new) |= value & bits;
1103
1104         pgste_set_unlock(ptep, new);
1105         pte_unmap_unlock(ptep, ptl);
1106         return 0;
1107 }
1108 EXPORT_SYMBOL(set_pgste_bits);
1109
1110 /**
1111  * get_pgste - get the current PGSTE for the given address.
1112  * @mm: the memory context. It must have PGSTEs, no check is performed here!
1113  * @hva: the host virtual address of the page whose PGSTE is to be processed
1114  * @pgstep: will be written with the current PGSTE for the given address.
1115  *
1116  * Return: 0 on success, < 0 in case of error.
1117  */
1118 int get_pgste(struct mm_struct *mm, unsigned long hva, unsigned long *pgstep)
1119 {
1120         spinlock_t *ptl;
1121         pte_t *ptep;
1122
1123         ptep = get_locked_pte(mm, hva, &ptl);
1124         if (unlikely(!ptep))
1125                 return -EFAULT;
1126         *pgstep = pgste_val(pgste_get(ptep));
1127         pte_unmap_unlock(ptep, ptl);
1128         return 0;
1129 }
1130 EXPORT_SYMBOL(get_pgste);
1131 #endif