Merge tag 'powerpc-4.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc...

[cascardo/linux.git] / arch / powerpc / mm / hugetlbpage.c

diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 119d186..a5d3ecd 100644 (file)
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -81,6 +81,13 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
        if (! new)
                return -ENOMEM;
 
+       /*
+        * Make sure other cpus find the hugepd set only after a
+        * properly initialized page table is visible to them.
+        * For more details look for comment in __pte_alloc().
+        */
+       smp_wmb();
+
        spin_lock(&mm->page_table_lock);
 #ifdef CONFIG_PPC_FSL_BOOK3E
        /*
@@ -1012,8 +1019,15 @@ int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
 
        pte = READ_ONCE(*ptep);
        mask = _PAGE_PRESENT | _PAGE_READ;
+
+       /*
+        * On some CPUs like the 8xx, _PAGE_RW hence _PAGE_WRITE is defined
+        * as 0 and _PAGE_RO has to be set when a page is not writable
+        */
        if (write)
                mask |= _PAGE_WRITE;
+       else
+               mask |= _PAGE_RO;
 
        if ((pte_val(pte) & mask) != mask)
                return 0;