Commit:     84e0fdb1754d066dd0a8b257de7299f392d1e727
Parent:     87cde760abfa019b5e368186f893cf673d227632
Author:     Huang, Ying <[EMAIL PROTECTED]>
AuthorDate: Wed Oct 17 18:04:35 2007 +0200
Committer:  Thomas Gleixner <[EMAIL PROTECTED]>
CommitDate: Wed Oct 17 20:15:43 2007 +0200

    x86: NX bit handling in change_page_attr()
    This patch fixes a bug of change_page_attr/change_page_attr_addr on
    Intel x86_64 CPUs.  After changing page attribute to be executable with
    these functions, the page remains un-executable on Intel x86_64 CPU.
    Because on Intel x86_64 CPU, only if the "NX" bits of all four level
    page tables are cleared, the corresponding page is executable (refer to
    section 4.13.2 of Intel 64 and IA-32 Architectures Software Developer's
    Manual).  So, the bug is fixed through clearing the "NX" bit of PMD when
    splitting the huge PMD.
    Signed-off-by: Huang Ying <[EMAIL PROTECTED]>
    Cc: Andi Kleen <[EMAIL PROTECTED]>
    Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
    Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]>
    Signed-off-by: Thomas Gleixner <[EMAIL PROTECTED]>
 arch/x86/mm/pageattr_64.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/arch/x86/mm/pageattr_64.c b/arch/x86/mm/pageattr_64.c
index 10b9809..93d795d 100644
--- a/arch/x86/mm/pageattr_64.c
+++ b/arch/x86/mm/pageattr_64.c
@@ -148,6 +148,7 @@ __change_page_attr(unsigned long address, unsigned long 
pfn, pgprot_t prot,
                        split = split_large_page(address, prot, ref_prot2);
                        if (!split)
                                return -ENOMEM;
+                       pgprot_val(ref_prot2) &= ~_PAGE_NX;
                        set_pte(kpte, mk_pte(split, ref_prot2));
                        kpte_page = split;
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