1 files changed, 11 insertions, 5 deletions

diff --git a/arch/x86/mm/pageattr_64.c b/arch/x86/mm/pageattr_64.c
index 139795029fb6..60cfb687f97c 100644
--- a/arch/x86/mm/pageattr_64.c
+++ b/arch/x86/mm/pageattr_64.c
@@ -126,30 +126,36 @@ out_unlock:
 static int
 __change_page_attr(unsigned long address, struct page *page, pgprot_t prot)
 {
-        pgprot_t ref_prot2, oldprot;
         struct page *kpte_page;
         int level, err = 0;
         pte_t *kpte;
 
+        BUG_ON(PageHighMem(page));
+
 repeat:
         kpte = lookup_address(address, &level);
         if (!kpte)
                 return 0;
 
         kpte_page = virt_to_page(kpte);
-        oldprot = pte_pgprot(*kpte);
         BUG_ON(PageLRU(kpte_page));
         BUG_ON(PageCompound(kpte_page));
-        prot = canon_pgprot(prot);
+
+        /*
+         * Better fail early if someone sets the kernel text to NX.
+         * Does not cover __inittext
+         */
+        BUG_ON(address >= (unsigned long)&_text &&
+                address < (unsigned long)&_etext &&
+               (pgprot_val(prot) & _PAGE_NX));
 
         if (level == 4) {
-                set_pte_atomic(kpte, mk_pte(page, prot));
+                set_pte_atomic(kpte, mk_pte(page, canon_pgprot(prot)));
         } else {
                 err = split_large_page(kpte, address);
                 if (!err)
                         goto repeat;
         }
-
         return err;
 }