x86: CPA no alias checking for _NX

NX settings are not required to be consistent across alias mappings.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 5 insertions, 2 deletions

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 7b4a17236972..b8f53233151d 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -669,7 +669,7 @@ static int change_page_attr_set_clr(unsigned long addr, int numpages,
                                     pgprot_t mask_set, pgprot_t mask_clr)
 {
         struct cpa_data cpa;
-        int ret, cache;
+        int ret, cache, checkalias;
 
         /*
          * Check, if we are requested to change a not supported
@@ -695,7 +695,10 @@ static int change_page_attr_set_clr(unsigned long addr, int numpages,
         cpa.mask_clr = mask_clr;
         cpa.flushtlb = 0;
 
-        ret = __change_page_attr_set_clr(&cpa, 1);
+        /* No alias checking for _NX bit modifications */
+        checkalias = (pgprot_val(mask_set) | pgprot_val(mask_clr)) != _PAGE_NX;
+
+        ret = __change_page_attr_set_clr(&cpa, checkalias);
 
         /*
          * Check whether we really changed something: