1 files changed, 77 insertions, 32 deletions

diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 034721a68d8f..c16232cd0ec5 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -429,22 +429,36 @@ static inline pmd_t pmdp_flush_lazy(struct mm_struct *mm,
 }
 
 #ifdef CONFIG_PGSTE
-static pmd_t *pmd_alloc_map(struct mm_struct *mm, unsigned long addr)
+static int pmd_lookup(struct mm_struct *mm, unsigned long addr, pmd_t **pmdp)
 {
+	struct vm_area_struct *vma;
 	pgd_t *pgd;
 	p4d_t *p4d;
 	pud_t *pud;
-	pmd_t *pmd;
+
+	/* We need a valid VMA, otherwise this is clearly a fault. */
+	vma = vma_lookup(mm, addr);
+	if (!vma)
+		return -EFAULT;
 
 	pgd = pgd_offset(mm, addr);
-	p4d = p4d_alloc(mm, pgd, addr);
-	if (!p4d)
-		return NULL;
-	pud = pud_alloc(mm, p4d, addr);
-	if (!pud)
-		return NULL;
-	pmd = pmd_alloc(mm, pud, addr);
-	return pmd;
+	if (!pgd_present(*pgd))
+		return -ENOENT;
+
+	p4d = p4d_offset(pgd, addr);
+	if (!p4d_present(*p4d))
+		return -ENOENT;
+
+	pud = pud_offset(p4d, addr);
+	if (!pud_present(*pud))
+		return -ENOENT;
+
+	/* Large PUDs are not supported yet. */
+	if (pud_large(*pud))
+		return -EFAULT;
+
+	*pmdp = pmd_offset(pud, addr);
+	return 0;
 }
 #endif
 
@@ -778,14 +792,23 @@ int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 	pmd_t *pmdp;
 	pte_t *ptep;
 
-	pmdp = pmd_alloc_map(mm, addr);
-	if (unlikely(!pmdp))
+	/*
+	 * If we don't have a PTE table and if there is no huge page mapped,
+	 * we can ignore attempts to set the key to 0, because it already is 0.
+	 */
+	switch (pmd_lookup(mm, addr, &pmdp)) {
+	case -ENOENT:
+		return key ? -EFAULT : 0;
+	case 0:
+		break;
+	default:
 		return -EFAULT;
+	}
 
 	ptl = pmd_lock(mm, pmdp);
 	if (!pmd_present(*pmdp)) {
 		spin_unlock(ptl);
-		return -EFAULT;
+		return key ? -EFAULT : 0;
 	}
 
 	if (pmd_large(*pmdp)) {
@@ -801,10 +824,7 @@ int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 	}
 	spin_unlock(ptl);
 
-	ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
-	if (unlikely(!ptep))
-		return -EFAULT;
-
+	ptep = pte_offset_map_lock(mm, pmdp, addr, &ptl);
 	new = old = pgste_get_lock(ptep);
 	pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT |
 			    PGSTE_ACC_BITS | PGSTE_FP_BIT);
@@ -881,14 +901,23 @@ int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr)
 	pte_t *ptep;
 	int cc = 0;
 
-	pmdp = pmd_alloc_map(mm, addr);
-	if (unlikely(!pmdp))
+	/*
+	 * If we don't have a PTE table and if there is no huge page mapped,
+	 * the storage key is 0 and there is nothing for us to do.
+	 */
+	switch (pmd_lookup(mm, addr, &pmdp)) {
+	case -ENOENT:
+		return 0;
+	case 0:
+		break;
+	default:
 		return -EFAULT;
+	}
 
 	ptl = pmd_lock(mm, pmdp);
 	if (!pmd_present(*pmdp)) {
 		spin_unlock(ptl);
-		return -EFAULT;
+		return 0;
 	}
 
 	if (pmd_large(*pmdp)) {
@@ -900,10 +929,7 @@ int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr)
 	}
 	spin_unlock(ptl);
 
-	ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
-	if (unlikely(!ptep))
-		return -EFAULT;
-
+	ptep = pte_offset_map_lock(mm, pmdp, addr, &ptl);
 	new = old = pgste_get_lock(ptep);
 	/* Reset guest reference bit only */
 	pgste_val(new) &= ~PGSTE_GR_BIT;
@@ -935,15 +961,24 @@ int get_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 	pmd_t *pmdp;
 	pte_t *ptep;
 
-	pmdp = pmd_alloc_map(mm, addr);
-	if (unlikely(!pmdp))
+	/*
+	 * If we don't have a PTE table and if there is no huge page mapped,
+	 * the storage key is 0.
+	 */
+	*key = 0;
+
+	switch (pmd_lookup(mm, addr, &pmdp)) {
+	case -ENOENT:
+		return 0;
+	case 0:
+		break;
+	default:
 		return -EFAULT;
+	}
 
 	ptl = pmd_lock(mm, pmdp);
 	if (!pmd_present(*pmdp)) {
-		/* Not yet mapped memory has a zero key */
 		spin_unlock(ptl);
-		*key = 0;
 		return 0;
 	}
 
@@ -956,10 +991,7 @@ int get_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 	}
 	spin_unlock(ptl);
 
-	ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
-	if (unlikely(!ptep))
-		return -EFAULT;
-
+	ptep = pte_offset_map_lock(mm, pmdp, addr, &ptl);
 	pgste = pgste_get_lock(ptep);
 	*key = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
 	paddr = pte_val(*ptep) & PAGE_MASK;
@@ -988,6 +1020,7 @@ EXPORT_SYMBOL(get_guest_storage_key);
 int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc,
 			unsigned long *oldpte, unsigned long *oldpgste)
 {
+	struct vm_area_struct *vma;
 	unsigned long pgstev;
 	spinlock_t *ptl;
 	pgste_t pgste;
@@ -997,6 +1030,10 @@ int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc,
 	WARN_ON_ONCE(orc > ESSA_MAX);
 	if (unlikely(orc > ESSA_MAX))
 		return -EINVAL;
+
+	vma = vma_lookup(mm, hva);
+	if (!vma || is_vm_hugetlb_page(vma))
+		return -EFAULT;
 	ptep = get_locked_pte(mm, hva, &ptl);
 	if (unlikely(!ptep))
 		return -EFAULT;
@@ -1089,10 +1126,14 @@ EXPORT_SYMBOL(pgste_perform_essa);
 int set_pgste_bits(struct mm_struct *mm, unsigned long hva,
 			unsigned long bits, unsigned long value)
 {
+	struct vm_area_struct *vma;
 	spinlock_t *ptl;
 	pgste_t new;
 	pte_t *ptep;
 
+	vma = vma_lookup(mm, hva);
+	if (!vma || is_vm_hugetlb_page(vma))
+		return -EFAULT;
 	ptep = get_locked_pte(mm, hva, &ptl);
 	if (unlikely(!ptep))
 		return -EFAULT;
@@ -1117,9 +1158,13 @@ EXPORT_SYMBOL(set_pgste_bits);
  */
 int get_pgste(struct mm_struct *mm, unsigned long hva, unsigned long *pgstep)
 {
+	struct vm_area_struct *vma;
 	spinlock_t *ptl;
 	pte_t *ptep;
 
+	vma = vma_lookup(mm, hva);
+	if (!vma || is_vm_hugetlb_page(vma))
+		return -EFAULT;
 	ptep = get_locked_pte(mm, hva, &ptl);
 	if (unlikely(!ptep))
 		return -EFAULT;