LXR linux/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
  29static 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
  49static 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
  69static 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
  88static 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
 108static 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
 127static 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
 139static 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
 148static 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
 155static 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
 176static 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
 198static 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
 221static 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
 237static 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
 249static 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
 270pte_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}
 285EXPORT_SYMBOL(ptep_xchg_direct);
 286
 287pte_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}
 302EXPORT_SYMBOL(ptep_xchg_lazy);
 303
 304pte_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}
 321EXPORT_SYMBOL(ptep_modify_prot_start);
 322
 323void 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}
 340EXPORT_SYMBOL(ptep_modify_prot_commit);
 341
 342static inline void pmdp_idte_local(struct mm_struct *mm,
 343                                   unsigned long addr, pmd_t *pmdp)
 344{
 345        if (MACHINE_HAS_TLB_GUEST)
 346                __pmdp_idte(addr, pmdp, IDTE_NODAT | IDTE_GUEST_ASCE,
 347                            mm->context.asce, IDTE_LOCAL);
 348        else
 349                __pmdp_idte(addr, pmdp, 0, 0, IDTE_LOCAL);
 350}
 351
 352static inline void pmdp_idte_global(struct mm_struct *mm,
 353                                    unsigned long addr, pmd_t *pmdp)
 354{
 355        if (MACHINE_HAS_TLB_GUEST)
 356                __pmdp_idte(addr, pmdp, IDTE_NODAT | IDTE_GUEST_ASCE,
 357                            mm->context.asce, IDTE_GLOBAL);
 358        else if (MACHINE_HAS_IDTE)
 359                __pmdp_idte(addr, pmdp, 0, 0, IDTE_GLOBAL);
 360        else
 361                __pmdp_csp(pmdp);
 362}
 363
 364static inline pmd_t pmdp_flush_direct(struct mm_struct *mm,
 365                                      unsigned long addr, pmd_t *pmdp)
 366{
 367        pmd_t old;
 368
 369        old = *pmdp;
 370        if (pmd_val(old) & _SEGMENT_ENTRY_INVALID)
 371                return old;
 372        atomic_inc(&mm->context.flush_count);
 373        if (MACHINE_HAS_TLB_LC &&
 374            cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
 375                pmdp_idte_local(mm, addr, pmdp);
 376        else
 377                pmdp_idte_global(mm, addr, pmdp);
 378        atomic_dec(&mm->context.flush_count);
 379        return old;
 380}
 381
 382static inline pmd_t pmdp_flush_lazy(struct mm_struct *mm,
 383                                    unsigned long addr, pmd_t *pmdp)
 384{
 385        pmd_t old;
 386
 387        old = *pmdp;
 388        if (pmd_val(old) & _SEGMENT_ENTRY_INVALID)
 389                return old;
 390        atomic_inc(&mm->context.flush_count);
 391        if (cpumask_equal(&mm->context.cpu_attach_mask,
 392                          cpumask_of(smp_processor_id()))) {
 393                pmd_val(*pmdp) |= _SEGMENT_ENTRY_INVALID;
 394                mm->context.flush_mm = 1;
 395        } else {
 396                pmdp_idte_global(mm, addr, pmdp);
 397        }
 398        atomic_dec(&mm->context.flush_count);
 399        return old;
 400}
 401
 402pmd_t pmdp_xchg_direct(struct mm_struct *mm, unsigned long addr,
 403                       pmd_t *pmdp, pmd_t new)
 404{
 405        pmd_t old;
 406
 407        preempt_disable();
 408        old = pmdp_flush_direct(mm, addr, pmdp);
 409        *pmdp = new;
 410        preempt_enable();
 411        return old;
 412}
 413EXPORT_SYMBOL(pmdp_xchg_direct);
 414
 415pmd_t pmdp_xchg_lazy(struct mm_struct *mm, unsigned long addr,
 416                     pmd_t *pmdp, pmd_t new)
 417{
 418        pmd_t old;
 419
 420        preempt_disable();
 421        old = pmdp_flush_lazy(mm, addr, pmdp);
 422        *pmdp = new;
 423        preempt_enable();
 424        return old;
 425}
 426EXPORT_SYMBOL(pmdp_xchg_lazy);
 427
 428static inline void pudp_idte_local(struct mm_struct *mm,
 429                                   unsigned long addr, pud_t *pudp)
 430{
 431        if (MACHINE_HAS_TLB_GUEST)
 432                __pudp_idte(addr, pudp, IDTE_NODAT | IDTE_GUEST_ASCE,
 433                            mm->context.asce, IDTE_LOCAL);
 434        else
 435                __pudp_idte(addr, pudp, 0, 0, IDTE_LOCAL);
 436}
 437
 438static inline void pudp_idte_global(struct mm_struct *mm,
 439                                    unsigned long addr, pud_t *pudp)
 440{
 441        if (MACHINE_HAS_TLB_GUEST)
 442                __pudp_idte(addr, pudp, IDTE_NODAT | IDTE_GUEST_ASCE,
 443                            mm->context.asce, IDTE_GLOBAL);
 444        else if (MACHINE_HAS_IDTE)
 445                __pudp_idte(addr, pudp, 0, 0, IDTE_GLOBAL);
 446        else
 447                /*
 448                 * Invalid bit position is the same for pmd and pud, so we can
 449                 * re-use _pmd_csp() here
 450                 */
 451                __pmdp_csp((pmd_t *) pudp);
 452}
 453
 454static inline pud_t pudp_flush_direct(struct mm_struct *mm,
 455                                      unsigned long addr, pud_t *pudp)
 456{
 457        pud_t old;
 458
 459        old = *pudp;
 460        if (pud_val(old) & _REGION_ENTRY_INVALID)
 461                return old;
 462        atomic_inc(&mm->context.flush_count);
 463        if (MACHINE_HAS_TLB_LC &&
 464            cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
 465                pudp_idte_local(mm, addr, pudp);
 466        else
 467                pudp_idte_global(mm, addr, pudp);
 468        atomic_dec(&mm->context.flush_count);
 469        return old;
 470}
 471
 472pud_t pudp_xchg_direct(struct mm_struct *mm, unsigned long addr,
 473                       pud_t *pudp, pud_t new)
 474{
 475        pud_t old;
 476
 477        preempt_disable();
 478        old = pudp_flush_direct(mm, addr, pudp);
 479        *pudp = new;
 480        preempt_enable();
 481        return old;
 482}
 483EXPORT_SYMBOL(pudp_xchg_direct);
 484
 485#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 486void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 487                                pgtable_t pgtable)
 488{
 489        struct list_head *lh = (struct list_head *) pgtable;
 490
 491        assert_spin_locked(pmd_lockptr(mm, pmdp));
 492
 493        /* FIFO */
 494        if (!pmd_huge_pte(mm, pmdp))
 495                INIT_LIST_HEAD(lh);
 496        else
 497                list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
 498        pmd_huge_pte(mm, pmdp) = pgtable;
 499}
 500
 501pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 502{
 503        struct list_head *lh;
 504        pgtable_t pgtable;
 505        pte_t *ptep;
 506
 507        assert_spin_locked(pmd_lockptr(mm, pmdp));
 508
 509        /* FIFO */
 510        pgtable = pmd_huge_pte(mm, pmdp);
 511        lh = (struct list_head *) pgtable;
 512        if (list_empty(lh))
 513                pmd_huge_pte(mm, pmdp) = NULL;
 514        else {
 515                pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
 516                list_del(lh);
 517        }
 518        ptep = (pte_t *) pgtable;
 519        pte_val(*ptep) = _PAGE_INVALID;
 520        ptep++;
 521        pte_val(*ptep) = _PAGE_INVALID;
 522        return pgtable;
 523}
 524#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 525
 526#ifdef CONFIG_PGSTE
 527void ptep_set_pte_at(struct mm_struct *mm, unsigned long addr,
 528                     pte_t *ptep, pte_t entry)
 529{
 530        pgste_t pgste;
 531
 532        /* the mm_has_pgste() check is done in set_pte_at() */
 533        preempt_disable();
 534        pgste = pgste_get_lock(ptep);
 535        pgste_val(pgste) &= ~_PGSTE_GPS_ZERO;
 536        pgste_set_key(ptep, pgste, entry, mm);
 537        pgste = pgste_set_pte(ptep, pgste, entry);
 538        pgste_set_unlock(ptep, pgste);
 539        preempt_enable();
 540}
 541
 542void ptep_set_notify(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 543{
 544        pgste_t pgste;
 545
 546        preempt_disable();
 547        pgste = pgste_get_lock(ptep);
 548        pgste_val(pgste) |= PGSTE_IN_BIT;
 549        pgste_set_unlock(ptep, pgste);
 550        preempt_enable();
 551}
 552
 553/**
 554 * ptep_force_prot - change access rights of a locked pte
 555 * @mm: pointer to the process mm_struct
 556 * @addr: virtual address in the guest address space
 557 * @ptep: pointer to the page table entry
 558 * @prot: indicates guest access rights: PROT_NONE, PROT_READ or PROT_WRITE
 559 * @bit: pgste bit to set (e.g. for notification)
 560 *
 561 * Returns 0 if the access rights were changed and -EAGAIN if the current
 562 * and requested access rights are incompatible.
 563 */
 564int ptep_force_prot(struct mm_struct *mm, unsigned long addr,
 565                    pte_t *ptep, int prot, unsigned long bit)
 566{
 567        pte_t entry;
 568        pgste_t pgste;
 569        int pte_i, pte_p, nodat;
 570
 571        pgste = pgste_get_lock(ptep);
 572        entry = *ptep;
 573        /* Check pte entry after all locks have been acquired */
 574        pte_i = pte_val(entry) & _PAGE_INVALID;
 575        pte_p = pte_val(entry) & _PAGE_PROTECT;
 576        if ((pte_i && (prot != PROT_NONE)) ||
 577            (pte_p && (prot & PROT_WRITE))) {
 578                pgste_set_unlock(ptep, pgste);
 579                return -EAGAIN;
 580        }
 581        /* Change access rights and set pgste bit */
 582        nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 583        if (prot == PROT_NONE && !pte_i) {
 584                ptep_flush_direct(mm, addr, ptep, nodat);
 585                pgste = pgste_update_all(entry, pgste, mm);
 586                pte_val(entry) |= _PAGE_INVALID;
 587        }
 588        if (prot == PROT_READ && !pte_p) {
 589                ptep_flush_direct(mm, addr, ptep, nodat);
 590                pte_val(entry) &= ~_PAGE_INVALID;
 591                pte_val(entry) |= _PAGE_PROTECT;
 592        }
 593        pgste_val(pgste) |= bit;
 594        pgste = pgste_set_pte(ptep, pgste, entry);
 595        pgste_set_unlock(ptep, pgste);
 596        return 0;
 597}
 598
 599int ptep_shadow_pte(struct mm_struct *mm, unsigned long saddr,
 600                    pte_t *sptep, pte_t *tptep, pte_t pte)
 601{
 602        pgste_t spgste, tpgste;
 603        pte_t spte, tpte;
 604        int rc = -EAGAIN;
 605
 606        if (!(pte_val(*tptep) & _PAGE_INVALID))
 607                return 0;       /* already shadowed */
 608        spgste = pgste_get_lock(sptep);
 609        spte = *sptep;
 610        if (!(pte_val(spte) & _PAGE_INVALID) &&
 611            !((pte_val(spte) & _PAGE_PROTECT) &&
 612              !(pte_val(pte) & _PAGE_PROTECT))) {
 613                pgste_val(spgste) |= PGSTE_VSIE_BIT;
 614                tpgste = pgste_get_lock(tptep);
 615                pte_val(tpte) = (pte_val(spte) & PAGE_MASK) |
 616                                (pte_val(pte) & _PAGE_PROTECT);
 617                /* don't touch the storage key - it belongs to parent pgste */
 618                tpgste = pgste_set_pte(tptep, tpgste, tpte);
 619                pgste_set_unlock(tptep, tpgste);
 620                rc = 1;
 621        }
 622        pgste_set_unlock(sptep, spgste);
 623        return rc;
 624}
 625
 626void ptep_unshadow_pte(struct mm_struct *mm, unsigned long saddr, pte_t *ptep)
 627{
 628        pgste_t pgste;
 629        int nodat;
 630
 631        pgste = pgste_get_lock(ptep);
 632        /* notifier is called by the caller */
 633        nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 634        ptep_flush_direct(mm, saddr, ptep, nodat);
 635        /* don't touch the storage key - it belongs to parent pgste */
 636        pgste = pgste_set_pte(ptep, pgste, __pte(_PAGE_INVALID));
 637        pgste_set_unlock(ptep, pgste);
 638}
 639
 640static void ptep_zap_swap_entry(struct mm_struct *mm, swp_entry_t entry)
 641{
 642        if (!non_swap_entry(entry))
 643                dec_mm_counter(mm, MM_SWAPENTS);
 644        else if (is_migration_entry(entry)) {
 645                struct page *page = migration_entry_to_page(entry);
 646
 647                dec_mm_counter(mm, mm_counter(page));
 648        }
 649        free_swap_and_cache(entry);
 650}
 651
 652void ptep_zap_unused(struct mm_struct *mm, unsigned long addr,
 653                     pte_t *ptep, int reset)
 654{
 655        unsigned long pgstev;
 656        pgste_t pgste;
 657        pte_t pte;
 658
 659        /* Zap unused and logically-zero pages */
 660        preempt_disable();
 661        pgste = pgste_get_lock(ptep);
 662        pgstev = pgste_val(pgste);
 663        pte = *ptep;
 664        if (!reset && pte_swap(pte) &&
 665            ((pgstev & _PGSTE_GPS_USAGE_MASK) == _PGSTE_GPS_USAGE_UNUSED ||
 666             (pgstev & _PGSTE_GPS_ZERO))) {
 667                ptep_zap_swap_entry(mm, pte_to_swp_entry(pte));
 668                pte_clear(mm, addr, ptep);
 669        }
 670        if (reset)
 671                pgste_val(pgste) &= ~_PGSTE_GPS_USAGE_MASK;
 672        pgste_set_unlock(ptep, pgste);
 673        preempt_enable();
 674}
 675
 676void ptep_zap_key(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 677{
 678        unsigned long ptev;
 679        pgste_t pgste;
 680
 681        /* Clear storage key ACC and F, but set R/C */
 682        preempt_disable();
 683        pgste = pgste_get_lock(ptep);
 684        pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT);
 685        pgste_val(pgste) |= PGSTE_GR_BIT | PGSTE_GC_BIT;
 686        ptev = pte_val(*ptep);
 687        if (!(ptev & _PAGE_INVALID) && (ptev & _PAGE_WRITE))
 688                page_set_storage_key(ptev & PAGE_MASK, PAGE_DEFAULT_KEY, 1);
 689        pgste_set_unlock(ptep, pgste);
 690        preempt_enable();
 691}
 692
 693/*
 694 * Test and reset if a guest page is dirty
 695 */
 696bool test_and_clear_guest_dirty(struct mm_struct *mm, unsigned long addr)
 697{
 698        spinlock_t *ptl;
 699        pgd_t *pgd;
 700        p4d_t *p4d;
 701        pud_t *pud;
 702        pmd_t *pmd;
 703        pgste_t pgste;
 704        pte_t *ptep;
 705        pte_t pte;
 706        bool dirty;
 707        int nodat;
 708
 709        pgd = pgd_offset(mm, addr);
 710        p4d = p4d_alloc(mm, pgd, addr);
 711        if (!p4d)
 712                return false;
 713        pud = pud_alloc(mm, p4d, addr);
 714        if (!pud)
 715                return false;
 716        pmd = pmd_alloc(mm, pud, addr);
 717        if (!pmd)
 718                return false;
 719        /* We can't run guests backed by huge pages, but userspace can
 720         * still set them up and then try to migrate them without any
 721         * migration support.
 722         */
 723        if (pmd_large(*pmd))
 724                return true;
 725
 726        ptep = pte_alloc_map_lock(mm, pmd, addr, &ptl);
 727        if (unlikely(!ptep))
 728                return false;
 729
 730        pgste = pgste_get_lock(ptep);
 731        dirty = !!(pgste_val(pgste) & PGSTE_UC_BIT);
 732        pgste_val(pgste) &= ~PGSTE_UC_BIT;
 733        pte = *ptep;
 734        if (dirty && (pte_val(pte) & _PAGE_PRESENT)) {
 735                pgste = pgste_pte_notify(mm, addr, ptep, pgste);
 736                nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 737                ptep_ipte_global(mm, addr, ptep, nodat);
 738                if (MACHINE_HAS_ESOP || !(pte_val(pte) & _PAGE_WRITE))
 739                        pte_val(pte) |= _PAGE_PROTECT;
 740                else
 741                        pte_val(pte) |= _PAGE_INVALID;
 742                *ptep = pte;
 743        }
 744        pgste_set_unlock(ptep, pgste);
 745
 746        spin_unlock(ptl);
 747        return dirty;
 748}
 749EXPORT_SYMBOL_GPL(test_and_clear_guest_dirty);
 750
 751int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 752                          unsigned char key, bool nq)
 753{
 754        unsigned long keyul;
 755        spinlock_t *ptl;
 756        pgste_t old, new;
 757        pte_t *ptep;
 758
 759        ptep = get_locked_pte(mm, addr, &ptl);
 760        if (unlikely(!ptep))
 761                return -EFAULT;
 762
 763        new = old = pgste_get_lock(ptep);
 764        pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT |
 765                            PGSTE_ACC_BITS | PGSTE_FP_BIT);
 766        keyul = (unsigned long) key;
 767        pgste_val(new) |= (keyul & (_PAGE_CHANGED | _PAGE_REFERENCED)) << 48;
 768        pgste_val(new) |= (keyul & (_PAGE_ACC_BITS | _PAGE_FP_BIT)) << 56;
 769        if (!(pte_val(*ptep) & _PAGE_INVALID)) {
 770                unsigned long address, bits, skey;
 771
 772                address = pte_val(*ptep) & PAGE_MASK;
 773                skey = (unsigned long) page_get_storage_key(address);
 774                bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED);
 775                skey = key & (_PAGE_ACC_BITS | _PAGE_FP_BIT);
 776                /* Set storage key ACC and FP */
 777                page_set_storage_key(address, skey, !nq);
 778                /* Merge host changed & referenced into pgste  */
 779                pgste_val(new) |= bits << 52;
 780        }
 781        /* changing the guest storage key is considered a change of the page */
 782        if ((pgste_val(new) ^ pgste_val(old)) &
 783            (PGSTE_ACC_BITS | PGSTE_FP_BIT | PGSTE_GR_BIT | PGSTE_GC_BIT))
 784                pgste_val(new) |= PGSTE_UC_BIT;
 785
 786        pgste_set_unlock(ptep, new);
 787        pte_unmap_unlock(ptep, ptl);
 788        return 0;
 789}
 790EXPORT_SYMBOL(set_guest_storage_key);
 791
 792/**
 793 * Conditionally set a guest storage key (handling csske).
 794 * oldkey will be updated when either mr or mc is set and a pointer is given.
 795 *
 796 * Returns 0 if a guests storage key update wasn't necessary, 1 if the guest
 797 * storage key was updated and -EFAULT on access errors.
 798 */
 799int cond_set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 800                               unsigned char key, unsigned char *oldkey,
 801                               bool nq, bool mr, bool mc)
 802{
 803        unsigned char tmp, mask = _PAGE_ACC_BITS | _PAGE_FP_BIT;
 804        int rc;
 805
 806        /* we can drop the pgste lock between getting and setting the key */
 807        if (mr | mc) {
 808                rc = get_guest_storage_key(current->mm, addr, &tmp);
 809                if (rc)
 810                        return rc;
 811                if (oldkey)
 812                        *oldkey = tmp;
 813                if (!mr)
 814                        mask |= _PAGE_REFERENCED;
 815                if (!mc)
 816                        mask |= _PAGE_CHANGED;
 817                if (!((tmp ^ key) & mask))
 818                        return 0;
 819        }
 820        rc = set_guest_storage_key(current->mm, addr, key, nq);
 821        return rc < 0 ? rc : 1;
 822}
 823EXPORT_SYMBOL(cond_set_guest_storage_key);
 824
 825/**
 826 * Reset a guest reference bit (rrbe), returning the reference and changed bit.
 827 *
 828 * Returns < 0 in case of error, otherwise the cc to be reported to the guest.
 829 */
 830int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr)
 831{
 832        spinlock_t *ptl;
 833        pgste_t old, new;
 834        pte_t *ptep;
 835        int cc = 0;
 836
 837        ptep = get_locked_pte(mm, addr, &ptl);
 838        if (unlikely(!ptep))
 839                return -EFAULT;
 840
 841        new = old = pgste_get_lock(ptep);
 842        /* Reset guest reference bit only */
 843        pgste_val(new) &= ~PGSTE_GR_BIT;
 844
 845        if (!(pte_val(*ptep) & _PAGE_INVALID)) {
 846                cc = page_reset_referenced(pte_val(*ptep) & PAGE_MASK);
 847                /* Merge real referenced bit into host-set */
 848                pgste_val(new) |= ((unsigned long) cc << 53) & PGSTE_HR_BIT;
 849        }
 850        /* Reflect guest's logical view, not physical */
 851        cc |= (pgste_val(old) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 49;
 852        /* Changing the guest storage key is considered a change of the page */
 853        if ((pgste_val(new) ^ pgste_val(old)) & PGSTE_GR_BIT)
 854                pgste_val(new) |= PGSTE_UC_BIT;
 855
 856        pgste_set_unlock(ptep, new);
 857        pte_unmap_unlock(ptep, ptl);
 858        return cc;
 859}
 860EXPORT_SYMBOL(reset_guest_reference_bit);
 861
 862int get_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 863                          unsigned char *key)
 864{
 865        spinlock_t *ptl;
 866        pgste_t pgste;
 867        pte_t *ptep;
 868
 869        ptep = get_locked_pte(mm, addr, &ptl);
 870        if (unlikely(!ptep))
 871                return -EFAULT;
 872
 873        pgste = pgste_get_lock(ptep);
 874        *key = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
 875        if (!(pte_val(*ptep) & _PAGE_INVALID))
 876                *key = page_get_storage_key(pte_val(*ptep) & PAGE_MASK);
 877        /* Reflect guest's logical view, not physical */
 878        *key |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48;
 879        pgste_set_unlock(ptep, pgste);
 880        pte_unmap_unlock(ptep, ptl);
 881        return 0;
 882}
 883EXPORT_SYMBOL(get_guest_storage_key);
 884
 885/**
 886 * pgste_perform_essa - perform ESSA actions on the PGSTE.
 887 * @mm: the memory context. It must have PGSTEs, no check is performed here!
 888 * @hva: the host virtual address of the page whose PGSTE is to be processed
 889 * @orc: the specific action to perform, see the ESSA_SET_* macros.
 890 * @oldpte: the PTE will be saved there if the pointer is not NULL.
 891 * @oldpgste: the old PGSTE will be saved there if the pointer is not NULL.
 892 *
 893 * Return: 1 if the page is to be added to the CBRL, otherwise 0,
 894 *         or < 0 in case of error. -EINVAL is returned for invalid values
 895 *         of orc, -EFAULT for invalid addresses.
 896 */
 897int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc,
 898                        unsigned long *oldpte, unsigned long *oldpgste)
 899{
 900        unsigned long pgstev;
 901        spinlock_t *ptl;
 902        pgste_t pgste;
 903        pte_t *ptep;
 904        int res = 0;
 905
 906        WARN_ON_ONCE(orc > ESSA_MAX);
 907        if (unlikely(orc > ESSA_MAX))
 908                return -EINVAL;
 909        ptep = get_locked_pte(mm, hva, &ptl);
 910        if (unlikely(!ptep))
 911                return -EFAULT;
 912        pgste = pgste_get_lock(ptep);
 913        pgstev = pgste_val(pgste);
 914        if (oldpte)
 915                *oldpte = pte_val(*ptep);
 916        if (oldpgste)
 917                *oldpgste = pgstev;
 918
 919        switch (orc) {
 920        case ESSA_GET_STATE:
 921                break;
 922        case ESSA_SET_STABLE:
 923                pgstev &= ~(_PGSTE_GPS_USAGE_MASK | _PGSTE_GPS_NODAT);
 924                pgstev |= _PGSTE_GPS_USAGE_STABLE;
 925                break;
 926        case ESSA_SET_UNUSED:
 927                pgstev &= ~_PGSTE_GPS_USAGE_MASK;
 928                pgstev |= _PGSTE_GPS_USAGE_UNUSED;
 929                if (pte_val(*ptep) & _PAGE_INVALID)
 930                        res = 1;
 931                break;
 932        case ESSA_SET_VOLATILE:
 933                pgstev &= ~_PGSTE_GPS_USAGE_MASK;
 934                pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
 935                if (pte_val(*ptep) & _PAGE_INVALID)
 936                        res = 1;
 937                break;
 938        case ESSA_SET_POT_VOLATILE:
 939                pgstev &= ~_PGSTE_GPS_USAGE_MASK;
 940                if (!(pte_val(*ptep) & _PAGE_INVALID)) {
 941                        pgstev |= _PGSTE_GPS_USAGE_POT_VOLATILE;
 942                        break;
 943                }
 944                if (pgstev & _PGSTE_GPS_ZERO) {
 945                        pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
 946                        break;
 947                }
 948                if (!(pgstev & PGSTE_GC_BIT)) {
 949                        pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
 950                        res = 1;
 951                        break;
 952                }
 953                break;
 954        case ESSA_SET_STABLE_RESIDENT:
 955                pgstev &= ~_PGSTE_GPS_USAGE_MASK;
 956                pgstev |= _PGSTE_GPS_USAGE_STABLE;
 957                /*
 958                 * Since the resident state can go away any time after this
 959                 * call, we will not make this page resident. We can revisit
 960                 * this decision if a guest will ever start using this.
 961                 */
 962                break;
 963        case ESSA_SET_STABLE_IF_RESIDENT:
 964                if (!(pte_val(*ptep) & _PAGE_INVALID)) {
 965                        pgstev &= ~_PGSTE_GPS_USAGE_MASK;
 966                        pgstev |= _PGSTE_GPS_USAGE_STABLE;
 967                }
 968                break;
 969        case ESSA_SET_STABLE_NODAT:
 970                pgstev &= ~_PGSTE_GPS_USAGE_MASK;
 971                pgstev |= _PGSTE_GPS_USAGE_STABLE | _PGSTE_GPS_NODAT;
 972                break;
 973        default:
 974                /* we should never get here! */
 975                break;
 976        }
 977        /* If we are discarding a page, set it to logical zero */
 978        if (res)
 979                pgstev |= _PGSTE_GPS_ZERO;
 980
 981        pgste_val(pgste) = pgstev;
 982        pgste_set_unlock(ptep, pgste);
 983        pte_unmap_unlock(ptep, ptl);
 984        return res;
 985}
 986EXPORT_SYMBOL(pgste_perform_essa);
 987
 988/**
 989 * set_pgste_bits - set specific PGSTE bits.
 990 * @mm: the memory context. It must have PGSTEs, no check is performed here!
 991 * @hva: the host virtual address of the page whose PGSTE is to be processed
 992 * @bits: a bitmask representing the bits that will be touched
 993 * @value: the values of the bits to be written. Only the bits in the mask
 994 *         will be written.
 995 *
 996 * Return: 0 on success, < 0 in case of error.
 997 */
 998int set_pgste_bits(struct mm_struct *mm, unsigned long hva,
 999                        unsigned long bits, unsigned long value)
1000{

1001        spinlock_t *ptl;
1002        pgste_t new;
1003        pte_t *ptep;
1004
1005        ptep = get_locked_pte(mm, hva, &ptl);
1006        if (unlikely(!ptep))
1007                return -EFAULT;
1008        new = pgste_get_lock(ptep);
1009
1010        pgste_val(new) &= ~bits;
1011        pgste_val(new) |= value & bits;
1012
1013        pgste_set_unlock(ptep, new);
1014        pte_unmap_unlock(ptep, ptl);
1015        return 0;
1016}
1017EXPORT_SYMBOL(set_pgste_bits);
1018
1019/**
1020 * get_pgste - get the current PGSTE for the given address.
1021 * @mm: the memory context. It must have PGSTEs, no check is performed here!
1022 * @hva: the host virtual address of the page whose PGSTE is to be processed
1023 * @pgstep: will be written with the current PGSTE for the given address.
1024 *
1025 * Return: 0 on success, < 0 in case of error.
1026 */
1027int get_pgste(struct mm_struct *mm, unsigned long hva, unsigned long *pgstep)
1028{
1029        spinlock_t *ptl;
1030        pte_t *ptep;
1031
1032        ptep = get_locked_pte(mm, hva, &ptl);
1033        if (unlikely(!ptep))
1034                return -EFAULT;
1035        *pgstep = pgste_val(pgste_get(ptep));
1036        pte_unmap_unlock(ptep, ptl);
1037        return 0;
1038}
1039EXPORT_SYMBOL(get_pgste);
1040#endif
1041