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    Subject[PATCH] [34/36] CPA: Add a BUG_ON checking for someone setting the kernel text NX
    Date

    Someone setting NX on the kernel text tends to result in nasty failures
    and triple faults, so BUG_ON early for that.

    Does not cover __inittext.

    Signed-off-by: Andi Kleen <ak@suse.de>
    Acked-by: Jan Beulich <jbeulich@novell.com>

    ---
    arch/x86/mm/pageattr_32.c | 8 ++++++++
    1 file changed, 8 insertions(+)

    Index: linux/arch/x86/mm/pageattr_32.c
    ===================================================================
    --- linux.orig/arch/x86/mm/pageattr_32.c
    +++ linux/arch/x86/mm/pageattr_32.c
    @@ -242,6 +242,14 @@ __change_page_attr(struct page *page, pg
    BUG_ON(PageLRU(kpte_page));
    BUG_ON(PageCompound(kpte_page));

    + /*
    + * 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));
    +
    set_tlb_flush(address, cache_attr_changed(*kpte, prot, level),
    level < 3);


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