1 files changed, 108 insertions, 0 deletions

diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index b402991e43d7..c8188a18af05 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -787,6 +787,30 @@ void tlb_remove_table(struct mmu_gather *tlb, void *table)
                 tlb_table_flush(tlb);
 }
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+void thp_split_vma(struct vm_area_struct *vma)
+{
+        unsigned long addr;
+        struct page *page;
+
+        for (addr = vma->vm_start; addr < vma->vm_end; addr += PAGE_SIZE) {
+                page = follow_page(vma, addr, FOLL_SPLIT);
+        }
+}
+
+void thp_split_mm(struct mm_struct *mm)
+{
+        struct vm_area_struct *vma = mm->mmap;
+
+        while (vma != NULL) {
+                thp_split_vma(vma);
+                vma->vm_flags &= ~VM_HUGEPAGE;
+                vma->vm_flags |= VM_NOHUGEPAGE;
+                vma = vma->vm_next;
+        }
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
 /*
  * switch on pgstes for its userspace process (for kvm)
  */
@@ -824,6 +848,12 @@ int s390_enable_sie(void)
         if (!mm)
                 return -ENOMEM;
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+        /* split thp mappings and disable thp for future mappings */
+        thp_split_mm(mm);
+        mm->def_flags |= VM_NOHUGEPAGE;
+#endif
+
         /* Now lets check again if something happened */
         task_lock(tsk);
         if (!tsk->mm || atomic_read(&tsk->mm->mm_users) > 1 ||
@@ -866,3 +896,81 @@ bool kernel_page_present(struct page *page)
         return cc == 0;
 }
 #endif /* CONFIG_HIBERNATION && CONFIG_DEBUG_PAGEALLOC */
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+int pmdp_clear_flush_young(struct vm_area_struct *vma, unsigned long address,
+                           pmd_t *pmdp)
+{
+        VM_BUG_ON(address & ~HPAGE_PMD_MASK);
+        /* No need to flush TLB
+         * On s390 reference bits are in storage key and never in TLB */
+        return pmdp_test_and_clear_young(vma, address, pmdp);
+}
+
+int pmdp_set_access_flags(struct vm_area_struct *vma,
+                          unsigned long address, pmd_t *pmdp,
+                          pmd_t entry, int dirty)
+{
+        VM_BUG_ON(address & ~HPAGE_PMD_MASK);
+
+        if (pmd_same(*pmdp, entry))
+                return 0;
+        pmdp_invalidate(vma, address, pmdp);
+        set_pmd_at(vma->vm_mm, address, pmdp, entry);
+        return 1;
+}
+
+static void pmdp_splitting_flush_sync(void *arg)
+{
+        /* Simply deliver the interrupt */
+}
+
+void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
+                          pmd_t *pmdp)
+{
+        VM_BUG_ON(address & ~HPAGE_PMD_MASK);
+        if (!test_and_set_bit(_SEGMENT_ENTRY_SPLIT_BIT,
+                              (unsigned long *) pmdp)) {
+                /* need to serialize against gup-fast (IRQ disabled) */
+                smp_call_function(pmdp_splitting_flush_sync, NULL, 1);
+        }
+}
+
+void pgtable_trans_huge_deposit(struct mm_struct *mm, pgtable_t pgtable)
+{
+        struct list_head *lh = (struct list_head *) pgtable;
+
+        assert_spin_locked(&mm->page_table_lock);
+
+        /* FIFO */
+        if (!mm->pmd_huge_pte)
+                INIT_LIST_HEAD(lh);
+        else
+                list_add(lh, (struct list_head *) mm->pmd_huge_pte);
+        mm->pmd_huge_pte = pgtable;
+}
+
+pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm)
+{
+        struct list_head *lh;
+        pgtable_t pgtable;
+        pte_t *ptep;
+
+        assert_spin_locked(&mm->page_table_lock);
+
+        /* FIFO */
+        pgtable = mm->pmd_huge_pte;
+        lh = (struct list_head *) pgtable;
+        if (list_empty(lh))
+                mm->pmd_huge_pte = NULL;
+        else {
+                mm->pmd_huge_pte = (pgtable_t) lh->next;
+                list_del(lh);
+        }
+        ptep = (pte_t *) pgtable;
+        pte_val(*ptep) = _PAGE_TYPE_EMPTY;
+        ptep++;
+        pte_val(*ptep) = _PAGE_TYPE_EMPTY;
+        return pgtable;
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */