diff options
Diffstat (limited to 'arch/s390/mm/pgtable.c')
| -rw-r--r-- | arch/s390/mm/pgtable.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index 4909dcd762e8..6effb24de6d9 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -302,6 +302,31 @@ pte_t ptep_xchg_direct(struct mm_struct *mm, unsigned long addr, } EXPORT_SYMBOL(ptep_xchg_direct); +/* + * Caller must check that new PTE only differs in _PAGE_PROTECT HW bit, so that + * RDP can be used instead of IPTE. See also comments at pte_allow_rdp(). + */ +void ptep_reset_dat_prot(struct mm_struct *mm, unsigned long addr, pte_t *ptep, + pte_t new) +{ + preempt_disable(); + atomic_inc(&mm->context.flush_count); + if (cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id()))) + __ptep_rdp(addr, ptep, 0, 0, 1); + else + __ptep_rdp(addr, ptep, 0, 0, 0); + /* + * PTE is not invalidated by RDP, only _PAGE_PROTECT is cleared. That + * means it is still valid and active, and must not be changed according + * to the architecture. But writing a new value that only differs in SW + * bits is allowed. + */ + set_pte(ptep, new); + atomic_dec(&mm->context.flush_count); + preempt_enable(); +} +EXPORT_SYMBOL(ptep_reset_dat_prot); + pte_t ptep_xchg_lazy(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t new) { |