1 files changed, 29 insertions, 18 deletions

diff --git a/arch/x86/mm/gup.c b/arch/x86/mm/gup.c
index d8a798d8b..b8b6a60b3 100644
--- a/arch/x86/mm/gup.c
+++ b/arch/x86/mm/gup.c
@@ -11,6 +11,7 @@
 #include <linux/swap.h>
 #include <linux/memremap.h>
 
+#include <asm/mmu_context.h>
 #include <asm/pgtable.h>
 
 static inline pte_t gup_get_pte(pte_t *ptep)
@@ -75,6 +76,28 @@ static void undo_dev_pagemap(int *nr, int nr_start, struct page **pages)
 }
 
 /*
+ * 'pteval' can come from a pte, pmd or pud.  We only check
+ * _PAGE_PRESENT, _PAGE_USER, and _PAGE_RW in here which are the
+ * same value on all 3 types.
+ */
+static inline int pte_allows_gup(unsigned long pteval, int write)
+{
+	unsigned long need_pte_bits = _PAGE_PRESENT|_PAGE_USER;
+
+	if (write)
+		need_pte_bits |= _PAGE_RW;
+
+	if ((pteval & need_pte_bits) != need_pte_bits)
+		return 0;
+
+	/* Check memory protection keys permissions. */
+	if (!__pkru_allows_pkey(pte_flags_pkey(pteval), write))
+		return 0;
+
+	return 1;
+}
+
+/*
  * The performance critical leaf functions are made noinline otherwise gcc
  * inlines everything into a single function which results in too much
  * register pressure.
@@ -83,14 +106,9 @@ static noinline int gup_pte_range(pmd_t pmd, unsigned long addr,
 		unsigned long end, int write, struct page **pages, int *nr)
 {
 	struct dev_pagemap *pgmap = NULL;
-	unsigned long mask;
 	int nr_start = *nr;
 	pte_t *ptep;
 
-	mask = _PAGE_PRESENT|_PAGE_USER;
-	if (write)
-		mask |= _PAGE_RW;
-
 	ptep = pte_offset_map(&pmd, addr);
 	do {
 		pte_t pte = gup_get_pte(ptep);
@@ -109,7 +127,8 @@ static noinline int gup_pte_range(pmd_t pmd, unsigned long addr,
 				pte_unmap(ptep);
 				return 0;
 			}
-		} else if ((pte_flags(pte) & (mask | _PAGE_SPECIAL)) != mask) {
+		} else if (!pte_allows_gup(pte_val(pte), write) ||
+			   pte_special(pte)) {
 			pte_unmap(ptep);
 			return 0;
 		}
@@ -131,7 +150,7 @@ static inline void get_head_page_multiple(struct page *page, int nr)
 {
 	VM_BUG_ON_PAGE(page != compound_head(page), page);
 	VM_BUG_ON_PAGE(page_count(page) == 0, page);
-	atomic_add(nr, &page->_count);
+	page_ref_add(page, nr);
 	SetPageReferenced(page);
 }
 
@@ -164,14 +183,10 @@ static int __gup_device_huge_pmd(pmd_t pmd, unsigned long addr,
 static noinline int gup_huge_pmd(pmd_t pmd, unsigned long addr,
 		unsigned long end, int write, struct page **pages, int *nr)
 {
-	unsigned long mask;
 	struct page *head, *page;
 	int refs;
 
-	mask = _PAGE_PRESENT|_PAGE_USER;
-	if (write)
-		mask |= _PAGE_RW;
-	if ((pmd_flags(pmd) & mask) != mask)
+	if (!pte_allows_gup(pmd_val(pmd), write))
 		return 0;
 
 	VM_BUG_ON(!pfn_valid(pmd_pfn(pmd)));
@@ -231,14 +246,10 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end,
 static noinline int gup_huge_pud(pud_t pud, unsigned long addr,
 		unsigned long end, int write, struct page **pages, int *nr)
 {
-	unsigned long mask;
 	struct page *head, *page;
 	int refs;
 
-	mask = _PAGE_PRESENT|_PAGE_USER;
-	if (write)
-		mask |= _PAGE_RW;
-	if ((pud_flags(pud) & mask) != mask)
+	if (!pte_allows_gup(pud_val(pud), write))
 		return 0;
 	/* hugepages are never "special" */
 	VM_BUG_ON(pud_flags(pud) & _PAGE_SPECIAL);
@@ -422,7 +433,7 @@ slow_irqon:
 		start += nr << PAGE_SHIFT;
 		pages += nr;
 
-		ret = get_user_pages_unlocked(current, mm, start,
+		ret = get_user_pages_unlocked(start,
 					      (end - start) >> PAGE_SHIFT,
 					      write, 0, pages);