diff options
Diffstat (limited to 'arch/s390/mm/pgtable.c')
| -rw-r--r-- | arch/s390/mm/pgtable.c | 209 |
1 files changed, 174 insertions, 35 deletions
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index b98d1a152d46..5f092015aaa7 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -174,14 +174,17 @@ static inline pgste_t pgste_set_pte(pte_t *ptep, pgste_t pgste, pte_t entry) return pgste; } -static inline pgste_t pgste_ipte_notify(struct mm_struct *mm, - unsigned long addr, - pte_t *ptep, pgste_t pgste) +static inline pgste_t pgste_pte_notify(struct mm_struct *mm, + unsigned long addr, + pte_t *ptep, pgste_t pgste) { #ifdef CONFIG_PGSTE - if (pgste_val(pgste) & PGSTE_IN_BIT) { - pgste_val(pgste) &= ~PGSTE_IN_BIT; - ptep_notify(mm, addr, ptep); + unsigned long bits; + + bits = pgste_val(pgste) & (PGSTE_IN_BIT | PGSTE_VSIE_BIT); + if (bits) { + pgste_val(pgste) ^= bits; + ptep_notify(mm, addr, ptep, bits); } #endif return pgste; @@ -194,7 +197,7 @@ static inline pgste_t ptep_xchg_start(struct mm_struct *mm, if (mm_has_pgste(mm)) { pgste = pgste_get_lock(ptep); - pgste = pgste_ipte_notify(mm, addr, ptep, pgste); + pgste = pgste_pte_notify(mm, addr, ptep, pgste); } return pgste; } @@ -459,6 +462,90 @@ void ptep_set_notify(struct mm_struct *mm, unsigned long addr, pte_t *ptep) preempt_enable(); } +/** + * ptep_force_prot - change access rights of a locked pte + * @mm: pointer to the process mm_struct + * @addr: virtual address in the guest address space + * @ptep: pointer to the page table entry + * @prot: indicates guest access rights: PROT_NONE, PROT_READ or PROT_WRITE + * @bit: pgste bit to set (e.g. for notification) + * + * Returns 0 if the access rights were changed and -EAGAIN if the current + * and requested access rights are incompatible. + */ +int ptep_force_prot(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, int prot, unsigned long bit) +{ + pte_t entry; + pgste_t pgste; + int pte_i, pte_p; + + pgste = pgste_get_lock(ptep); + entry = *ptep; + /* Check pte entry after all locks have been acquired */ + pte_i = pte_val(entry) & _PAGE_INVALID; + pte_p = pte_val(entry) & _PAGE_PROTECT; + if ((pte_i && (prot != PROT_NONE)) || + (pte_p && (prot & PROT_WRITE))) { + pgste_set_unlock(ptep, pgste); + return -EAGAIN; + } + /* Change access rights and set pgste bit */ + if (prot == PROT_NONE && !pte_i) { + ptep_flush_direct(mm, addr, ptep); + pgste = pgste_update_all(entry, pgste, mm); + pte_val(entry) |= _PAGE_INVALID; + } + if (prot == PROT_READ && !pte_p) { + ptep_flush_direct(mm, addr, ptep); + pte_val(entry) &= ~_PAGE_INVALID; + pte_val(entry) |= _PAGE_PROTECT; + } + pgste_val(pgste) |= bit; + pgste = pgste_set_pte(ptep, pgste, entry); + pgste_set_unlock(ptep, pgste); + return 0; +} + +int ptep_shadow_pte(struct mm_struct *mm, unsigned long saddr, + pte_t *sptep, pte_t *tptep, pte_t pte) +{ + pgste_t spgste, tpgste; + pte_t spte, tpte; + int rc = -EAGAIN; + + if (!(pte_val(*tptep) & _PAGE_INVALID)) + return 0; /* already shadowed */ + spgste = pgste_get_lock(sptep); + spte = *sptep; + if (!(pte_val(spte) & _PAGE_INVALID) && + !((pte_val(spte) & _PAGE_PROTECT) && + !(pte_val(pte) & _PAGE_PROTECT))) { + pgste_val(spgste) |= PGSTE_VSIE_BIT; + tpgste = pgste_get_lock(tptep); + pte_val(tpte) = (pte_val(spte) & PAGE_MASK) | + (pte_val(pte) & _PAGE_PROTECT); + /* don't touch the storage key - it belongs to parent pgste */ + tpgste = pgste_set_pte(tptep, tpgste, tpte); + pgste_set_unlock(tptep, tpgste); + rc = 1; + } + pgste_set_unlock(sptep, spgste); + return rc; +} + +void ptep_unshadow_pte(struct mm_struct *mm, unsigned long saddr, pte_t *ptep) +{ + pgste_t pgste; + + pgste = pgste_get_lock(ptep); + /* notifier is called by the caller */ + ptep_flush_direct(mm, saddr, ptep); + /* don't touch the storage key - it belongs to parent pgste */ + pgste = pgste_set_pte(ptep, pgste, __pte(_PAGE_INVALID)); + pgste_set_unlock(ptep, pgste); +} + static void ptep_zap_swap_entry(struct mm_struct *mm, swp_entry_t entry) { if (!non_swap_entry(entry)) @@ -532,7 +619,7 @@ bool test_and_clear_guest_dirty(struct mm_struct *mm, unsigned long addr) pgste_val(pgste) &= ~PGSTE_UC_BIT; pte = *ptep; if (dirty && (pte_val(pte) & _PAGE_PRESENT)) { - pgste = pgste_ipte_notify(mm, addr, ptep, pgste); + pgste = pgste_pte_notify(mm, addr, ptep, pgste); __ptep_ipte(addr, ptep); if (MACHINE_HAS_ESOP || !(pte_val(pte) & _PAGE_WRITE)) pte_val(pte) |= _PAGE_PROTECT; @@ -555,12 +642,9 @@ int set_guest_storage_key(struct mm_struct *mm, unsigned long addr, pgste_t old, new; pte_t *ptep; - down_read(&mm->mmap_sem); ptep = get_locked_pte(mm, addr, &ptl); - if (unlikely(!ptep)) { - up_read(&mm->mmap_sem); + if (unlikely(!ptep)) return -EFAULT; - } new = old = pgste_get_lock(ptep); pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT | @@ -587,45 +671,100 @@ int set_guest_storage_key(struct mm_struct *mm, unsigned long addr, pgste_set_unlock(ptep, new); pte_unmap_unlock(ptep, ptl); - up_read(&mm->mmap_sem); return 0; } EXPORT_SYMBOL(set_guest_storage_key); -unsigned char get_guest_storage_key(struct mm_struct *mm, unsigned long addr) +/** + * Conditionally set a guest storage key (handling csske). + * oldkey will be updated when either mr or mc is set and a pointer is given. + * + * Returns 0 if a guests storage key update wasn't necessary, 1 if the guest + * storage key was updated and -EFAULT on access errors. + */ +int cond_set_guest_storage_key(struct mm_struct *mm, unsigned long addr, + unsigned char key, unsigned char *oldkey, + bool nq, bool mr, bool mc) +{ + unsigned char tmp, mask = _PAGE_ACC_BITS | _PAGE_FP_BIT; + int rc; + + /* we can drop the pgste lock between getting and setting the key */ + if (mr | mc) { + rc = get_guest_storage_key(current->mm, addr, &tmp); + if (rc) + return rc; + if (oldkey) + *oldkey = tmp; + if (!mr) + mask |= _PAGE_REFERENCED; + if (!mc) + mask |= _PAGE_CHANGED; + if (!((tmp ^ key) & mask)) + return 0; + } + rc = set_guest_storage_key(current->mm, addr, key, nq); + return rc < 0 ? rc : 1; +} +EXPORT_SYMBOL(cond_set_guest_storage_key); + +/** + * Reset a guest reference bit (rrbe), returning the reference and changed bit. + * + * Returns < 0 in case of error, otherwise the cc to be reported to the guest. + */ +int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr) { - unsigned char key; spinlock_t *ptl; - pgste_t pgste; + pgste_t old, new; pte_t *ptep; + int cc = 0; - down_read(&mm->mmap_sem); ptep = get_locked_pte(mm, addr, &ptl); - if (unlikely(!ptep)) { - up_read(&mm->mmap_sem); + if (unlikely(!ptep)) return -EFAULT; - } - pgste = pgste_get_lock(ptep); - if (pte_val(*ptep) & _PAGE_INVALID) { - key = (pgste_val(pgste) & PGSTE_ACC_BITS) >> 56; - key |= (pgste_val(pgste) & PGSTE_FP_BIT) >> 56; - key |= (pgste_val(pgste) & PGSTE_GR_BIT) >> 48; - key |= (pgste_val(pgste) & PGSTE_GC_BIT) >> 48; - } else { - key = page_get_storage_key(pte_val(*ptep) & PAGE_MASK); + new = old = pgste_get_lock(ptep); + /* Reset guest reference bit only */ + pgste_val(new) &= ~PGSTE_GR_BIT; - /* Reflect guest's logical view, not physical */ - if (pgste_val(pgste) & PGSTE_GR_BIT) - key |= _PAGE_REFERENCED; - if (pgste_val(pgste) & PGSTE_GC_BIT) - key |= _PAGE_CHANGED; + if (!(pte_val(*ptep) & _PAGE_INVALID)) { + cc = page_reset_referenced(pte_val(*ptep) & PAGE_MASK); + /* Merge real referenced bit into host-set */ + pgste_val(new) |= ((unsigned long) cc << 53) & PGSTE_HR_BIT; } + /* Reflect guest's logical view, not physical */ + cc |= (pgste_val(old) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 49; + /* Changing the guest storage key is considered a change of the page */ + if ((pgste_val(new) ^ pgste_val(old)) & PGSTE_GR_BIT) + pgste_val(new) |= PGSTE_UC_BIT; + + pgste_set_unlock(ptep, new); + pte_unmap_unlock(ptep, ptl); + return 0; +} +EXPORT_SYMBOL(reset_guest_reference_bit); + +int get_guest_storage_key(struct mm_struct *mm, unsigned long addr, + unsigned char *key) +{ + spinlock_t *ptl; + pgste_t pgste; + pte_t *ptep; + ptep = get_locked_pte(mm, addr, &ptl); + if (unlikely(!ptep)) + return -EFAULT; + + pgste = pgste_get_lock(ptep); + *key = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56; + if (!(pte_val(*ptep) & _PAGE_INVALID)) + *key = page_get_storage_key(pte_val(*ptep) & PAGE_MASK); + /* Reflect guest's logical view, not physical */ + *key |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48; pgste_set_unlock(ptep, pgste); pte_unmap_unlock(ptep, ptl); - up_read(&mm->mmap_sem); - return key; + return 0; } EXPORT_SYMBOL(get_guest_storage_key); #endif |