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 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
 323void 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
 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        if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)
 351                gmap_pmdp_idte_local(mm, addr);
 352}
 353
 354static 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
 373static 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
 391static 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
 413static pmd_t *pmd_alloc_map(struct mm_struct *mm, unsigned long addr)
 414{
 415        pgd_t *pgd;
 416        p4d_t *p4d;
 417        pud_t *pud;
 418        pmd_t *pmd;
 419
 420        pgd = pgd_offset(mm, addr);
 421        p4d = p4d_alloc(mm, pgd, addr);
 422        if (!p4d)
 423                return NULL;
 424        pud = pud_alloc(mm, p4d, addr);
 425        if (!pud)
 426                return NULL;
 427        pmd = pmd_alloc(mm, pud, addr);
 428        return pmd;
 429}
 430
 431pmd_t pmdp_xchg_direct(struct mm_struct *mm, unsigned long addr,
 432                       pmd_t *pmdp, pmd_t new)
 433{
 434        pmd_t old;
 435
 436        preempt_disable();
 437        old = pmdp_flush_direct(mm, addr, pmdp);
 438        *pmdp = new;
 439        preempt_enable();
 440        return old;
 441}
 442EXPORT_SYMBOL(pmdp_xchg_direct);
 443
 444pmd_t pmdp_xchg_lazy(struct mm_struct *mm, unsigned long addr,
 445                     pmd_t *pmdp, pmd_t new)
 446{
 447        pmd_t old;
 448
 449        preempt_disable();
 450        old = pmdp_flush_lazy(mm, addr, pmdp);
 451        *pmdp = new;
 452        preempt_enable();
 453        return old;
 454}
 455EXPORT_SYMBOL(pmdp_xchg_lazy);
 456
 457static inline void pudp_idte_local(struct mm_struct *mm,
 458                                   unsigned long addr, pud_t *pudp)
 459{
 460        if (MACHINE_HAS_TLB_GUEST)
 461                __pudp_idte(addr, pudp, IDTE_NODAT | IDTE_GUEST_ASCE,
 462                            mm->context.asce, IDTE_LOCAL);
 463        else
 464                __pudp_idte(addr, pudp, 0, 0, IDTE_LOCAL);
 465}
 466
 467static inline void pudp_idte_global(struct mm_struct *mm,
 468                                    unsigned long addr, pud_t *pudp)
 469{
 470        if (MACHINE_HAS_TLB_GUEST)
 471                __pudp_idte(addr, pudp, IDTE_NODAT | IDTE_GUEST_ASCE,
 472                            mm->context.asce, IDTE_GLOBAL);
 473        else if (MACHINE_HAS_IDTE)
 474                __pudp_idte(addr, pudp, 0, 0, IDTE_GLOBAL);
 475        else
 476                /*
 477                 * Invalid bit position is the same for pmd and pud, so we can
 478                 * re-use _pmd_csp() here
 479                 */
 480                __pmdp_csp((pmd_t *) pudp);
 481}
 482
 483static inline pud_t pudp_flush_direct(struct mm_struct *mm,
 484                                      unsigned long addr, pud_t *pudp)
 485{
 486        pud_t old;
 487
 488        old = *pudp;
 489        if (pud_val(old) & _REGION_ENTRY_INVALID)
 490                return old;
 491        atomic_inc(&mm->context.flush_count);
 492        if (MACHINE_HAS_TLB_LC &&
 493            cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
 494                pudp_idte_local(mm, addr, pudp);
 495        else
 496                pudp_idte_global(mm, addr, pudp);
 497        atomic_dec(&mm->context.flush_count);
 498        return old;
 499}
 500
 501pud_t pudp_xchg_direct(struct mm_struct *mm, unsigned long addr,
 502                       pud_t *pudp, pud_t new)
 503{
 504        pud_t old;
 505
 506        preempt_disable();
 507        old = pudp_flush_direct(mm, addr, pudp);
 508        *pudp = new;
 509        preempt_enable();
 510        return old;
 511}
 512EXPORT_SYMBOL(pudp_xchg_direct);
 513
 514#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 515void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 516                                pgtable_t pgtable)
 517{
 518        struct list_head *lh = (struct list_head *) pgtable;
 519
 520        assert_spin_locked(pmd_lockptr(mm, pmdp));
 521
 522        /* FIFO */
 523        if (!pmd_huge_pte(mm, pmdp))
 524                INIT_LIST_HEAD(lh);
 525        else
 526                list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
 527        pmd_huge_pte(mm, pmdp) = pgtable;
 528}
 529
 530pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 531{
 532        struct list_head *lh;
 533        pgtable_t pgtable;
 534        pte_t *ptep;
 535
 536        assert_spin_locked(pmd_lockptr(mm, pmdp));
 537
 538        /* FIFO */
 539        pgtable = pmd_huge_pte(mm, pmdp);
 540        lh = (struct list_head *) pgtable;
 541        if (list_empty(lh))
 542                pmd_huge_pte(mm, pmdp) = NULL;
 543        else {
 544                pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
 545                list_del(lh);
 546        }
 547        ptep = (pte_t *) pgtable;
 548        pte_val(*ptep) = _PAGE_INVALID;
 549        ptep++;
 550        pte_val(*ptep) = _PAGE_INVALID;
 551        return pgtable;
 552}
 553#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 554
 555#ifdef CONFIG_PGSTE
 556void ptep_set_pte_at(struct mm_struct *mm, unsigned long addr,
 557                     pte_t *ptep, pte_t entry)
 558{
 559        pgste_t pgste;
 560
 561        /* the mm_has_pgste() check is done in set_pte_at() */
 562        preempt_disable();
 563        pgste = pgste_get_lock(ptep);
 564        pgste_val(pgste) &= ~_PGSTE_GPS_ZERO;
 565        pgste_set_key(ptep, pgste, entry, mm);
 566        pgste = pgste_set_pte(ptep, pgste, entry);
 567        pgste_set_unlock(ptep, pgste);
 568        preempt_enable();
 569}
 570
 571void ptep_set_notify(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 572{
 573        pgste_t pgste;
 574
 575        preempt_disable();
 576        pgste = pgste_get_lock(ptep);
 577        pgste_val(pgste) |= PGSTE_IN_BIT;
 578        pgste_set_unlock(ptep, pgste);
 579        preempt_enable();
 580}
 581
 582/**
 583 * ptep_force_prot - change access rights of a locked pte
 584 * @mm: pointer to the process mm_struct
 585 * @addr: virtual address in the guest address space
 586 * @ptep: pointer to the page table entry
 587 * @prot: indicates guest access rights: PROT_NONE, PROT_READ or PROT_WRITE
 588 * @bit: pgste bit to set (e.g. for notification)
 589 *
 590 * Returns 0 if the access rights were changed and -EAGAIN if the current
 591 * and requested access rights are incompatible.
 592 */
 593int ptep_force_prot(struct mm_struct *mm, unsigned long addr,
 594                    pte_t *ptep, int prot, unsigned long bit)
 595{
 596        pte_t entry;
 597        pgste_t pgste;
 598        int pte_i, pte_p, nodat;
 599
 600        pgste = pgste_get_lock(ptep);
 601        entry = *ptep;
 602        /* Check pte entry after all locks have been acquired */
 603        pte_i = pte_val(entry) & _PAGE_INVALID;
 604        pte_p = pte_val(entry) & _PAGE_PROTECT;
 605        if ((pte_i && (prot != PROT_NONE)) ||
 606            (pte_p && (prot & PROT_WRITE))) {
 607                pgste_set_unlock(ptep, pgste);
 608                return -EAGAIN;
 609        }
 610        /* Change access rights and set pgste bit */
 611        nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 612        if (prot == PROT_NONE && !pte_i) {
 613                ptep_flush_direct(mm, addr, ptep, nodat);
 614                pgste = pgste_update_all(entry, pgste, mm);
 615                pte_val(entry) |= _PAGE_INVALID;
 616        }
 617        if (prot == PROT_READ && !pte_p) {
 618                ptep_flush_direct(mm, addr, ptep, nodat);
 619                pte_val(entry) &= ~_PAGE_INVALID;
 620                pte_val(entry) |= _PAGE_PROTECT;
 621        }
 622        pgste_val(pgste) |= bit;
 623        pgste = pgste_set_pte(ptep, pgste, entry);
 624        pgste_set_unlock(ptep, pgste);
 625        return 0;
 626}
 627
 628int ptep_shadow_pte(struct mm_struct *mm, unsigned long saddr,
 629                    pte_t *sptep, pte_t *tptep, pte_t pte)
 630{
 631        pgste_t spgste, tpgste;
 632        pte_t spte, tpte;
 633        int rc = -EAGAIN;
 634
 635        if (!(pte_val(*tptep) & _PAGE_INVALID))
 636                return 0;       /* already shadowed */
 637        spgste = pgste_get_lock(sptep);
 638        spte = *sptep;
 639        if (!(pte_val(spte) & _PAGE_INVALID) &&
 640            !((pte_val(spte) & _PAGE_PROTECT) &&
 641              !(pte_val(pte) & _PAGE_PROTECT))) {
 642                pgste_val(spgste) |= PGSTE_VSIE_BIT;
 643                tpgste = pgste_get_lock(tptep);
 644                pte_val(tpte) = (pte_val(spte) & PAGE_MASK) |
 645                                (pte_val(pte) & _PAGE_PROTECT);
 646                /* don't touch the storage key - it belongs to parent pgste */
 647                tpgste = pgste_set_pte(tptep, tpgste, tpte);
 648                pgste_set_unlock(tptep, tpgste);
 649                rc = 1;
 650        }
 651        pgste_set_unlock(sptep, spgste);
 652        return rc;
 653}
 654
 655void ptep_unshadow_pte(struct mm_struct *mm, unsigned long saddr, pte_t *ptep)
 656{
 657        pgste_t pgste;
 658        int nodat;
 659
 660        pgste = pgste_get_lock(ptep);
 661        /* notifier is called by the caller */
 662        nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 663        ptep_flush_direct(mm, saddr, ptep, nodat);
 664        /* don't touch the storage key - it belongs to parent pgste */
 665        pgste = pgste_set_pte(ptep, pgste, __pte(_PAGE_INVALID));
 666        pgste_set_unlock(ptep, pgste);
 667}
 668
 669static void ptep_zap_swap_entry(struct mm_struct *mm, swp_entry_t entry)
 670{
 671        if (!non_swap_entry(entry))
 672                dec_mm_counter(mm, MM_SWAPENTS);
 673        else if (is_migration_entry(entry)) {
 674                struct page *page = migration_entry_to_page(entry);
 675
 676                dec_mm_counter(mm, mm_counter(page));
 677        }
 678        free_swap_and_cache(entry);
 679}
 680
 681void ptep_zap_unused(struct mm_struct *mm, unsigned long addr,
 682                     pte_t *ptep, int reset)
 683{
 684        unsigned long pgstev;
 685        pgste_t pgste;
 686        pte_t pte;
 687
 688        /* Zap unused and logically-zero pages */
 689        preempt_disable();
 690        pgste = pgste_get_lock(ptep);
 691        pgstev = pgste_val(pgste);
 692        pte = *ptep;
 693        if (!reset && pte_swap(pte) &&
 694            ((pgstev & _PGSTE_GPS_USAGE_MASK) == _PGSTE_GPS_USAGE_UNUSED ||
 695             (pgstev & _PGSTE_GPS_ZERO))) {
 696                ptep_zap_swap_entry(mm, pte_to_swp_entry(pte));
 697                pte_clear(mm, addr, ptep);
 698        }
 699        if (reset)
 700                pgste_val(pgste) &= ~_PGSTE_GPS_USAGE_MASK;
 701        pgste_set_unlock(ptep, pgste);
 702        preempt_enable();
 703}
 704
 705void ptep_zap_key(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 706{
 707        unsigned long ptev;
 708        pgste_t pgste;
 709
 710        /* Clear storage key ACC and F, but set R/C */
 711        preempt_disable();
 712        pgste = pgste_get_lock(ptep);
 713        pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT);
 714        pgste_val(pgste) |= PGSTE_GR_BIT | PGSTE_GC_BIT;
 715        ptev = pte_val(*ptep);
 716        if (!(ptev & _PAGE_INVALID) && (ptev & _PAGE_WRITE))
 717                page_set_storage_key(ptev & PAGE_MASK, PAGE_DEFAULT_KEY, 1);
 718        pgste_set_unlock(ptep, pgste);
 719        preempt_enable();
 720}
 721
 722/*
 723 * Test and reset if a guest page is dirty
 724 */
 725bool ptep_test_and_clear_uc(struct mm_struct *mm, unsigned long addr,
 726                       pte_t *ptep)
 727{
 728        pgste_t pgste;
 729        pte_t pte;
 730        bool dirty;
 731        int nodat;
 732
 733        pgste = pgste_get_lock(ptep);
 734        dirty = !!(pgste_val(pgste) & PGSTE_UC_BIT);
 735        pgste_val(pgste) &= ~PGSTE_UC_BIT;
 736        pte = *ptep;
 737        if (dirty && (pte_val(pte) & _PAGE_PRESENT)) {
 738                pgste = pgste_pte_notify(mm, addr, ptep, pgste);
 739                nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
 740                ptep_ipte_global(mm, addr, ptep, nodat);
 741                if (MACHINE_HAS_ESOP || !(pte_val(pte) & _PAGE_WRITE))
 742                        pte_val(pte) |= _PAGE_PROTECT;
 743                else
 744                        pte_val(pte) |= _PAGE_INVALID;
 745                *ptep = pte;
 746        }
 747        pgste_set_unlock(ptep, pgste);
 748        return dirty;
 749}
 750EXPORT_SYMBOL_GPL(ptep_test_and_clear_uc);
 751
 752int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 753                          unsigned char key, bool nq)
 754{
 755        unsigned long keyul, paddr;
 756        spinlock_t *ptl;
 757        pgste_t old, new;
 758        pmd_t *pmdp;
 759        pte_t *ptep;
 760
 761        pmdp = pmd_alloc_map(mm, addr);
 762        if (unlikely(!pmdp))
 763                return -EFAULT;
 764
 765        ptl = pmd_lock(mm, pmdp);
 766        if (!pmd_present(*pmdp)) {
 767                spin_unlock(ptl);
 768                return -EFAULT;
 769        }
 770
 771        if (pmd_large(*pmdp)) {
 772                paddr = pmd_val(*pmdp) & HPAGE_MASK;
 773                paddr |= addr & ~HPAGE_MASK;
 774                /*
 775                 * Huge pmds need quiescing operations, they are
 776                 * always mapped.
 777                 */
 778                page_set_storage_key(paddr, key, 1);
 779                spin_unlock(ptl);
 780                return 0;
 781        }
 782        spin_unlock(ptl);
 783
 784        ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
 785        if (unlikely(!ptep))
 786                return -EFAULT;
 787
 788        new = old = pgste_get_lock(ptep);
 789        pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT |
 790                            PGSTE_ACC_BITS | PGSTE_FP_BIT);
 791        keyul = (unsigned long) key;
 792        pgste_val(new) |= (keyul & (_PAGE_CHANGED | _PAGE_REFERENCED)) << 48;
 793        pgste_val(new) |= (keyul & (_PAGE_ACC_BITS | _PAGE_FP_BIT)) << 56;
 794        if (!(pte_val(*ptep) & _PAGE_INVALID)) {
 795                unsigned long bits, skey;
 796
 797                paddr = pte_val(*ptep) & PAGE_MASK;
 798                skey = (unsigned long) page_get_storage_key(paddr);
 799                bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED);
 800                skey = key & (_PAGE_ACC_BITS | _PAGE_FP_BIT);
 801                /* Set storage key ACC and FP */
 802                page_set_storage_key(paddr, skey, !nq);
 803                /* Merge host changed & referenced into pgste  */
 804                pgste_val(new) |= bits << 52;
 805        }
 806        /* changing the guest storage key is considered a change of the page */
 807        if ((pgste_val(new) ^ pgste_val(old)) &
 808            (PGSTE_ACC_BITS | PGSTE_FP_BIT | PGSTE_GR_BIT | PGSTE_GC_BIT))
 809                pgste_val(new) |= PGSTE_UC_BIT;
 810
 811        pgste_set_unlock(ptep, new);
 812        pte_unmap_unlock(ptep, ptl);
 813        return 0;
 814}
 815EXPORT_SYMBOL(set_guest_storage_key);
 816
 817/**
 818 * Conditionally set a guest storage key (handling csske).
 819 * oldkey will be updated when either mr or mc is set and a pointer is given.
 820 *
 821 * Returns 0 if a guests storage key update wasn't necessary, 1 if the guest
 822 * storage key was updated and -EFAULT on access errors.
 823 */
 824int cond_set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 825                               unsigned char key, unsigned char *oldkey,
 826                               bool nq, bool mr, bool mc)
 827{
 828        unsigned char tmp, mask = _PAGE_ACC_BITS | _PAGE_FP_BIT;
 829        int rc;
 830
 831        /* we can drop the pgste lock between getting and setting the key */
 832        if (mr | mc) {
 833                rc = get_guest_storage_key(current->mm, addr, &tmp);
 834                if (rc)
 835                        return rc;
 836                if (oldkey)
 837                        *oldkey = tmp;
 838                if (!mr)
 839                        mask |= _PAGE_REFERENCED;
 840                if (!mc)
 841                        mask |= _PAGE_CHANGED;
 842                if (!((tmp ^ key) & mask))
 843                        return 0;
 844        }
 845        rc = set_guest_storage_key(current->mm, addr, key, nq);
 846        return rc < 0 ? rc : 1;
 847}
 848EXPORT_SYMBOL(cond_set_guest_storage_key);
 849
 850/**
 851 * Reset a guest reference bit (rrbe), returning the reference and changed bit.
 852 *
 853 * Returns < 0 in case of error, otherwise the cc to be reported to the guest.
 854 */
 855int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr)
 856{
 857        spinlock_t *ptl;
 858        unsigned long paddr;
 859        pgste_t old, new;
 860        pmd_t *pmdp;
 861        pte_t *ptep;
 862        int cc = 0;
 863
 864        pmdp = pmd_alloc_map(mm, addr);
 865        if (unlikely(!pmdp))
 866                return -EFAULT;
 867
 868        ptl = pmd_lock(mm, pmdp);
 869        if (!pmd_present(*pmdp)) {
 870                spin_unlock(ptl);
 871                return -EFAULT;
 872        }
 873
 874        if (pmd_large(*pmdp)) {
 875                paddr = pmd_val(*pmdp) & HPAGE_MASK;
 876                paddr |= addr & ~HPAGE_MASK;
 877                cc = page_reset_referenced(paddr);
 878                spin_unlock(ptl);
 879                return cc;
 880        }
 881        spin_unlock(ptl);
 882
 883        ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
 884        if (unlikely(!ptep))
 885                return -EFAULT;
 886
 887        new = old = pgste_get_lock(ptep);
 888        /* Reset guest reference bit only */
 889        pgste_val(new) &= ~PGSTE_GR_BIT;
 890
 891        if (!(pte_val(*ptep) & _PAGE_INVALID)) {
 892                paddr = pte_val(*ptep) & PAGE_MASK;
 893                cc = page_reset_referenced(paddr);
 894                /* Merge real referenced bit into host-set */
 895                pgste_val(new) |= ((unsigned long) cc << 53) & PGSTE_HR_BIT;
 896        }
 897        /* Reflect guest's logical view, not physical */
 898        cc |= (pgste_val(old) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 49;
 899        /* Changing the guest storage key is considered a change of the page */
 900        if ((pgste_val(new) ^ pgste_val(old)) & PGSTE_GR_BIT)
 901                pgste_val(new) |= PGSTE_UC_BIT;
 902
 903        pgste_set_unlock(ptep, new);
 904        pte_unmap_unlock(ptep, ptl);
 905        return cc;
 906}
 907EXPORT_SYMBOL(reset_guest_reference_bit);
 908
 909int get_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 910                          unsigned char *key)
 911{
 912        unsigned long paddr;
 913        spinlock_t *ptl;
 914        pgste_t pgste;
 915        pmd_t *pmdp;
 916        pte_t *ptep;
 917
 918        pmdp = pmd_alloc_map(mm, addr);
 919        if (unlikely(!pmdp))
 920                return -EFAULT;
 921
 922        ptl = pmd_lock(mm, pmdp);
 923        if (!pmd_present(*pmdp)) {
 924                /* Not yet mapped memory has a zero key */
 925                spin_unlock(ptl);
 926                *key = 0;
 927                return 0;
 928        }
 929
 930        if (pmd_large(*pmdp)) {
 931                paddr = pmd_val(*pmdp) & HPAGE_MASK;
 932                paddr |= addr & ~HPAGE_MASK;
 933                *key = page_get_storage_key(paddr);
 934                spin_unlock(ptl);
 935                return 0;
 936        }
 937        spin_unlock(ptl);
 938
 939        ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
 940        if (unlikely(!ptep))
 941                return -EFAULT;
 942
 943        pgste = pgste_get_lock(ptep);
 944        *key = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
 945        paddr = pte_val(*ptep) & PAGE_MASK;
 946        if (!(pte_val(*ptep) & _PAGE_INVALID))
 947                *key = page_get_storage_key(paddr);
 948        /* Reflect guest's logical view, not physical */
 949        *key |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48;
 950        pgste_set_unlock(ptep, pgste);
 951        pte_unmap_unlock(ptep, ptl);
 952        return 0;
 953}
 954EXPORT_SYMBOL(get_guest_storage_key);
 955
 956/**
 957 * pgste_perform_essa - perform ESSA actions on the PGSTE.
 958 * @mm: the memory context. It must have PGSTEs, no check is performed here!
 959 * @hva: the host virtual address of the page whose PGSTE is to be processed
 960 * @orc: the specific action to perform, see the ESSA_SET_* macros.
 961 * @oldpte: the PTE will be saved there if the pointer is not NULL.
 962 * @oldpgste: the old PGSTE will be saved there if the pointer is not NULL.
 963 *
 964 * Return: 1 if the page is to be added to the CBRL, otherwise 0,
 965 *         or < 0 in case of error. -EINVAL is returned for invalid values
 966 *         of orc, -EFAULT for invalid addresses.
 967 */
 968int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc,
 969                        unsigned long *oldpte, unsigned long *oldpgste)
 970{
 971        unsigned long pgstev;
 972        spinlock_t *ptl;
 973        pgste_t pgste;
 974        pte_t *ptep;
 975        int res = 0;
 976
 977        WARN_ON_ONCE(orc > ESSA_MAX);
 978        if (unlikely(orc > ESSA_MAX))
 979                return -EINVAL;
 980        ptep = get_locked_pte(mm, hva, &ptl);
 981        if (unlikely(!ptep))
 982                return -EFAULT;
 983        pgste = pgste_get_lock(ptep);
 984        pgstev = pgste_val(pgste);
 985        if (oldpte)
 986                *oldpte = pte_val(*ptep);
 987        if (oldpgste)
 988                *oldpgste = pgstev;
 989
 990        switch (orc) {
 991        case ESSA_GET_STATE:
 992                break;
 993        case ESSA_SET_STABLE:
 994                pgstev &= ~(_PGSTE_GPS_USAGE_MASK | _PGSTE_GPS_NODAT);
 995                pgstev |= _PGSTE_GPS_USAGE_STABLE;
 996                break;
 997        case ESSA_SET_UNUSED:
 998                pgstev &= ~_PGSTE_GPS_USAGE_MASK;
 999                pgstev |= _PGSTE_GPS_USAGE_UNUSED;
1000                if (pte_val(*ptep) & _PAGE_INVALID)

1001                        res = 1;
1002                break;
1003        case ESSA_SET_VOLATILE:
1004                pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1005                pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
1006                if (pte_val(*ptep) & _PAGE_INVALID)
1007                        res = 1;
1008                break;
1009        case ESSA_SET_POT_VOLATILE:
1010                pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1011                if (!(pte_val(*ptep) & _PAGE_INVALID)) {
1012                        pgstev |= _PGSTE_GPS_USAGE_POT_VOLATILE;
1013                        break;
1014                }
1015                if (pgstev & _PGSTE_GPS_ZERO) {
1016                        pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
1017                        break;
1018                }
1019                if (!(pgstev & PGSTE_GC_BIT)) {
1020                        pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
1021                        res = 1;
1022                        break;
1023                }
1024                break;
1025        case ESSA_SET_STABLE_RESIDENT:
1026                pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1027                pgstev |= _PGSTE_GPS_USAGE_STABLE;
1028                /*
1029                 * Since the resident state can go away any time after this
1030                 * call, we will not make this page resident. We can revisit
1031                 * this decision if a guest will ever start using this.
1032                 */
1033                break;
1034        case ESSA_SET_STABLE_IF_RESIDENT:
1035                if (!(pte_val(*ptep) & _PAGE_INVALID)) {
1036                        pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1037                        pgstev |= _PGSTE_GPS_USAGE_STABLE;
1038                }
1039                break;
1040        case ESSA_SET_STABLE_NODAT:
1041                pgstev &= ~_PGSTE_GPS_USAGE_MASK;
1042                pgstev |= _PGSTE_GPS_USAGE_STABLE | _PGSTE_GPS_NODAT;
1043                break;
1044        default:
1045                /* we should never get here! */
1046                break;
1047        }
1048        /* If we are discarding a page, set it to logical zero */
1049        if (res)
1050                pgstev |= _PGSTE_GPS_ZERO;
1051
1052        pgste_val(pgste) = pgstev;
1053        pgste_set_unlock(ptep, pgste);
1054        pte_unmap_unlock(ptep, ptl);
1055        return res;
1056}
1057EXPORT_SYMBOL(pgste_perform_essa);
1058
1059/**
1060 * set_pgste_bits - set specific PGSTE bits.
1061 * @mm: the memory context. It must have PGSTEs, no check is performed here!
1062 * @hva: the host virtual address of the page whose PGSTE is to be processed
1063 * @bits: a bitmask representing the bits that will be touched
1064 * @value: the values of the bits to be written. Only the bits in the mask
1065 *         will be written.
1066 *
1067 * Return: 0 on success, < 0 in case of error.
1068 */
1069int set_pgste_bits(struct mm_struct *mm, unsigned long hva,
1070                        unsigned long bits, unsigned long value)
1071{
1072        spinlock_t *ptl;
1073        pgste_t new;
1074        pte_t *ptep;
1075
1076        ptep = get_locked_pte(mm, hva, &ptl);
1077        if (unlikely(!ptep))
1078                return -EFAULT;
1079        new = pgste_get_lock(ptep);
1080
1081        pgste_val(new) &= ~bits;
1082        pgste_val(new) |= value & bits;
1083
1084        pgste_set_unlock(ptep, new);
1085        pte_unmap_unlock(ptep, ptl);
1086        return 0;
1087}
1088EXPORT_SYMBOL(set_pgste_bits);
1089
1090/**
1091 * get_pgste - get the current PGSTE for the given address.
1092 * @mm: the memory context. It must have PGSTEs, no check is performed here!
1093 * @hva: the host virtual address of the page whose PGSTE is to be processed
1094 * @pgstep: will be written with the current PGSTE for the given address.
1095 *
1096 * Return: 0 on success, < 0 in case of error.
1097 */
1098int get_pgste(struct mm_struct *mm, unsigned long hva, unsigned long *pgstep)
1099{
1100        spinlock_t *ptl;
1101        pte_t *ptep;
1102
1103        ptep = get_locked_pte(mm, hva, &ptl);
1104        if (unlikely(!ptep))
1105                return -EFAULT;
1106        *pgstep = pgste_val(pgste_get(ptep));
1107        pte_unmap_unlock(ptep, ptl);
1108        return 0;
1109}
1110EXPORT_SYMBOL(get_pgste);
1111#endif
1112