1 files changed, 264 insertions, 67 deletions

diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index ae44d2a34313..a938b548f07e 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -379,75 +379,184 @@ out_unmap:
 }
 EXPORT_SYMBOL_GPL(gmap_map_segment);
 
-/*
- * this function is assumed to be called with mmap_sem held
- */
-unsigned long __gmap_fault(unsigned long address, struct gmap *gmap)
+static unsigned long *gmap_table_walk(unsigned long address, struct gmap *gmap)
 {
-	unsigned long *table, vmaddr, segment;
-	struct mm_struct *mm;
-	struct gmap_pgtable *mp;
-	struct gmap_rmap *rmap;
-	struct vm_area_struct *vma;
-	struct page *page;
-	pgd_t *pgd;
-	pud_t *pud;
-	pmd_t *pmd;
+	unsigned long *table;
 
-	current->thread.gmap_addr = address;
-	mm = gmap->mm;
-	/* Walk the gmap address space page table */
 	table = gmap->table + ((address >> 53) & 0x7ff);
 	if (unlikely(*table & _REGION_ENTRY_INV))
-		return -EFAULT;
+		return ERR_PTR(-EFAULT);
 	table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 	table = table + ((address >> 42) & 0x7ff);
 	if (unlikely(*table & _REGION_ENTRY_INV))
-		return -EFAULT;
+		return ERR_PTR(-EFAULT);
 	table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 	table = table + ((address >> 31) & 0x7ff);
 	if (unlikely(*table & _REGION_ENTRY_INV))
-		return -EFAULT;
+		return ERR_PTR(-EFAULT);
 	table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 	table = table + ((address >> 20) & 0x7ff);
+	return table;
+}
 
+/**
+ * __gmap_translate - translate a guest address to a user space address
+ * @address: guest address
+ * @gmap: pointer to guest mapping meta data structure
+ *
+ * Returns user space address which corresponds to the guest address or
+ * -EFAULT if no such mapping exists.
+ * This function does not establish potentially missing page table entries.
+ * The mmap_sem of the mm that belongs to the address space must be held
+ * when this function gets called.
+ */
+unsigned long __gmap_translate(unsigned long address, struct gmap *gmap)
+{
+	unsigned long *segment_ptr, vmaddr, segment;
+	struct gmap_pgtable *mp;
+	struct page *page;
+
+	current->thread.gmap_addr = address;
+	segment_ptr = gmap_table_walk(address, gmap);
+	if (IS_ERR(segment_ptr))
+		return PTR_ERR(segment_ptr);
 	/* Convert the gmap address to an mm address. */
-	segment = *table;
-	if (likely(!(segment & _SEGMENT_ENTRY_INV))) {
+	segment = *segment_ptr;
+	if (!(segment & _SEGMENT_ENTRY_INV)) {
 		page = pfn_to_page(segment >> PAGE_SHIFT);
 		mp = (struct gmap_pgtable *) page->index;
 		return mp->vmaddr | (address & ~PMD_MASK);
 	} else if (segment & _SEGMENT_ENTRY_RO) {
 		vmaddr = segment & _SEGMENT_ENTRY_ORIGIN;
-		vma = find_vma(mm, vmaddr);
-		if (!vma || vma->vm_start > vmaddr)
-			return -EFAULT;
-
-		/* Walk the parent mm page table */
-		pgd = pgd_offset(mm, vmaddr);
-		pud = pud_alloc(mm, pgd, vmaddr);
-		if (!pud)
-			return -ENOMEM;
-		pmd = pmd_alloc(mm, pud, vmaddr);
-		if (!pmd)
-			return -ENOMEM;
-		if (!pmd_present(*pmd) &&
-		    __pte_alloc(mm, vma, pmd, vmaddr))
-			return -ENOMEM;
-		/* pmd now points to a valid segment table entry. */
-		rmap = kmalloc(sizeof(*rmap), GFP_KERNEL|__GFP_REPEAT);
-		if (!rmap)
-			return -ENOMEM;
-		/* Link gmap segment table entry location to page table. */
-		page = pmd_page(*pmd);
-		mp = (struct gmap_pgtable *) page->index;
-		rmap->entry = table;
-		spin_lock(&mm->page_table_lock);
+		return vmaddr | (address & ~PMD_MASK);
+	}
+	return -EFAULT;
+}
+EXPORT_SYMBOL_GPL(__gmap_translate);
+
+/**
+ * gmap_translate - translate a guest address to a user space address
+ * @address: guest address
+ * @gmap: pointer to guest mapping meta data structure
+ *
+ * Returns user space address which corresponds to the guest address or
+ * -EFAULT if no such mapping exists.
+ * This function does not establish potentially missing page table entries.
+ */
+unsigned long gmap_translate(unsigned long address, struct gmap *gmap)
+{
+	unsigned long rc;
+
+	down_read(&gmap->mm->mmap_sem);
+	rc = __gmap_translate(address, gmap);
+	up_read(&gmap->mm->mmap_sem);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(gmap_translate);
+
+static int gmap_connect_pgtable(unsigned long address, unsigned long segment,
+				unsigned long *segment_ptr, struct gmap *gmap)
+{
+	unsigned long vmaddr;
+	struct vm_area_struct *vma;
+	struct gmap_pgtable *mp;
+	struct gmap_rmap *rmap;
+	struct mm_struct *mm;
+	struct page *page;
+	pgd_t *pgd;
+	pud_t *pud;
+	pmd_t *pmd;
+
+	mm = gmap->mm;
+	vmaddr = segment & _SEGMENT_ENTRY_ORIGIN;
+	vma = find_vma(mm, vmaddr);
+	if (!vma || vma->vm_start > vmaddr)
+		return -EFAULT;
+	/* Walk the parent mm page table */
+	pgd = pgd_offset(mm, vmaddr);
+	pud = pud_alloc(mm, pgd, vmaddr);
+	if (!pud)
+		return -ENOMEM;
+	pmd = pmd_alloc(mm, pud, vmaddr);
+	if (!pmd)
+		return -ENOMEM;
+	if (!pmd_present(*pmd) &&
+	    __pte_alloc(mm, vma, pmd, vmaddr))
+		return -ENOMEM;
+	/* pmd now points to a valid segment table entry. */
+	rmap = kmalloc(sizeof(*rmap), GFP_KERNEL|__GFP_REPEAT);
+	if (!rmap)
+		return -ENOMEM;
+	/* Link gmap segment table entry location to page table. */
+	page = pmd_page(*pmd);
+	mp = (struct gmap_pgtable *) page->index;
+	rmap->gmap = gmap;
+	rmap->entry = segment_ptr;
+	rmap->vmaddr = address & PMD_MASK;
+	spin_lock(&mm->page_table_lock);
+	if (*segment_ptr == segment) {
 		list_add(&rmap->list, &mp->mapper);
-		spin_unlock(&mm->page_table_lock);
 		/* Set gmap segment table entry to page table. */
-		*table = pmd_val(*pmd) & PAGE_MASK;
-		return vmaddr | (address & ~PMD_MASK);
+		*segment_ptr = pmd_val(*pmd) & PAGE_MASK;
+		rmap = NULL;
+	}
+	spin_unlock(&mm->page_table_lock);
+	kfree(rmap);
+	return 0;
+}
+
+static void gmap_disconnect_pgtable(struct mm_struct *mm, unsigned long *table)
+{
+	struct gmap_rmap *rmap, *next;
+	struct gmap_pgtable *mp;
+	struct page *page;
+	int flush;
+
+	flush = 0;
+	spin_lock(&mm->page_table_lock);
+	page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
+	mp = (struct gmap_pgtable *) page->index;
+	list_for_each_entry_safe(rmap, next, &mp->mapper, list) {
+		*rmap->entry =
+			_SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | mp->vmaddr;
+		list_del(&rmap->list);
+		kfree(rmap);
+		flush = 1;
+	}
+	spin_unlock(&mm->page_table_lock);
+	if (flush)
+		__tlb_flush_global();
+}
+
+/*
+ * this function is assumed to be called with mmap_sem held
+ */
+unsigned long __gmap_fault(unsigned long address, struct gmap *gmap)
+{
+	unsigned long *segment_ptr, segment;
+	struct gmap_pgtable *mp;
+	struct page *page;
+	int rc;
+
+	current->thread.gmap_addr = address;
+	segment_ptr = gmap_table_walk(address, gmap);
+	if (IS_ERR(segment_ptr))
+		return -EFAULT;
+	/* Convert the gmap address to an mm address. */
+	while (1) {
+		segment = *segment_ptr;
+		if (!(segment & _SEGMENT_ENTRY_INV)) {
+			/* Page table is present */
+			page = pfn_to_page(segment >> PAGE_SHIFT);
+			mp = (struct gmap_pgtable *) page->index;
+			return mp->vmaddr | (address & ~PMD_MASK);
+		}
+		if (!(segment & _SEGMENT_ENTRY_RO))
+			/* Nothing mapped in the gmap address space. */
+			break;
+		rc = gmap_connect_pgtable(address, segment, segment_ptr, gmap);
+		if (rc)
+			return rc;
 	}
 	return -EFAULT;
 }
@@ -511,27 +620,115 @@ void gmap_discard(unsigned long from, unsigned long to, struct gmap *gmap)
 }
 EXPORT_SYMBOL_GPL(gmap_discard);
 
-void gmap_unmap_notifier(struct mm_struct *mm, unsigned long *table)
+static LIST_HEAD(gmap_notifier_list);
+static DEFINE_SPINLOCK(gmap_notifier_lock);
+
+/**
+ * gmap_register_ipte_notifier - register a pte invalidation callback
+ * @nb: pointer to the gmap notifier block
+ */
+void gmap_register_ipte_notifier(struct gmap_notifier *nb)
 {
-	struct gmap_rmap *rmap, *next;
+	spin_lock(&gmap_notifier_lock);
+	list_add(&nb->list, &gmap_notifier_list);
+	spin_unlock(&gmap_notifier_lock);
+}
+EXPORT_SYMBOL_GPL(gmap_register_ipte_notifier);
+
+/**
+ * gmap_unregister_ipte_notifier - remove a pte invalidation callback
+ * @nb: pointer to the gmap notifier block
+ */
+void gmap_unregister_ipte_notifier(struct gmap_notifier *nb)
+{
+	spin_lock(&gmap_notifier_lock);
+	list_del_init(&nb->list);
+	spin_unlock(&gmap_notifier_lock);
+}
+EXPORT_SYMBOL_GPL(gmap_unregister_ipte_notifier);
+
+/**
+ * gmap_ipte_notify - mark a range of ptes for invalidation notification
+ * @gmap: pointer to guest mapping meta data structure
+ * @address: virtual address in the guest address space
+ * @len: size of area
+ *
+ * Returns 0 if for each page in the given range a gmap mapping exists and
+ * the invalidation notification could be set. If the gmap mapping is missing
+ * for one or more pages -EFAULT is returned. If no memory could be allocated
+ * -ENOMEM is returned. This function establishes missing page table entries.
+ */
+int gmap_ipte_notify(struct gmap *gmap, unsigned long start, unsigned long len)
+{
+	unsigned long addr;
+	spinlock_t *ptl;
+	pte_t *ptep, entry;
+	pgste_t pgste;
+	int rc = 0;
+
+	if ((start & ~PAGE_MASK) || (len & ~PAGE_MASK))
+		return -EINVAL;
+	down_read(&gmap->mm->mmap_sem);
+	while (len) {
+		/* Convert gmap address and connect the page tables */
+		addr = __gmap_fault(start, gmap);
+		if (IS_ERR_VALUE(addr)) {
+			rc = addr;
+			break;
+		}
+		/* Get the page mapped */
+		if (fixup_user_fault(current, gmap->mm, addr, FAULT_FLAG_WRITE)) {
+			rc = -EFAULT;
+			break;
+		}
+		/* Walk the process page table, lock and get pte pointer */
+		ptep = get_locked_pte(gmap->mm, addr, &ptl);
+		if (unlikely(!ptep))
+			continue;
+		/* Set notification bit in the pgste of the pte */
+		entry = *ptep;
+		if ((pte_val(entry) & (_PAGE_INVALID | _PAGE_RO)) == 0) {
+			pgste = pgste_get_lock(ptep);
+			pgste_val(pgste) |= RCP_IN_BIT;
+			pgste_set_unlock(ptep, pgste);
+			start += PAGE_SIZE;
+			len -= PAGE_SIZE;
+		}
+		spin_unlock(ptl);
+	}
+	up_read(&gmap->mm->mmap_sem);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(gmap_ipte_notify);
+
+/**
+ * gmap_do_ipte_notify - call all invalidation callbacks for a specific pte.
+ * @mm: pointer to the process mm_struct
+ * @addr: virtual address in the process address space
+ * @pte: pointer to the page table entry
+ *
+ * This function is assumed to be called with the page table lock held
+ * for the pte to notify.
+ */
+void gmap_do_ipte_notify(struct mm_struct *mm, unsigned long addr, pte_t *pte)
+{
+	unsigned long segment_offset;
+	struct gmap_notifier *nb;
 	struct gmap_pgtable *mp;
+	struct gmap_rmap *rmap;
 	struct page *page;
-	int flush;
 
-	flush = 0;
-	spin_lock(&mm->page_table_lock);
-	page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
+	segment_offset = ((unsigned long) pte) & (255 * sizeof(pte_t));
+	segment_offset = segment_offset * (4096 / sizeof(pte_t));
+	page = pfn_to_page(__pa(pte) >> PAGE_SHIFT);
 	mp = (struct gmap_pgtable *) page->index;
-	list_for_each_entry_safe(rmap, next, &mp->mapper, list) {
-		*rmap->entry =
-			_SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | mp->vmaddr;
-		list_del(&rmap->list);
-		kfree(rmap);
-		flush = 1;
+	spin_lock(&gmap_notifier_lock);
+	list_for_each_entry(rmap, &mp->mapper, list) {
+		list_for_each_entry(nb, &gmap_notifier_list, list)
+			nb->notifier_call(rmap->gmap,
+					  rmap->vmaddr + segment_offset);
 	}
-	spin_unlock(&mm->page_table_lock);
-	if (flush)
-		__tlb_flush_global();
+	spin_unlock(&gmap_notifier_lock);
 }
 
 static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm,
@@ -586,8 +783,8 @@ static inline void page_table_free_pgste(unsigned long *table)
 {
 }
 
-static inline void gmap_unmap_notifier(struct mm_struct *mm,
-					  unsigned long *table)
+static inline void gmap_disconnect_pgtable(struct mm_struct *mm,
+					   unsigned long *table)
 {
 }
 
@@ -653,7 +850,7 @@ void page_table_free(struct mm_struct *mm, unsigned long *table)
 	unsigned int bit, mask;
 
 	if (mm_has_pgste(mm)) {
-		gmap_unmap_notifier(mm, table);
+		gmap_disconnect_pgtable(mm, table);
 		return page_table_free_pgste(table);
 	}
 	/* Free 1K/2K page table fragment of a 4K page */
@@ -696,7 +893,7 @@ void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table)
 
 	mm = tlb->mm;
 	if (mm_has_pgste(mm)) {
-		gmap_unmap_notifier(mm, table);
+		gmap_disconnect_pgtable(mm, table);
 		table = (unsigned long *) (__pa(table) | FRAG_MASK);
 		tlb_remove_table(tlb, table);
 		return;