Messages in this thread Patch in this message | | | Date | Tue, 20 Nov 2007 10:24:43 -0800 | From | Greg Kroah-Hartman <> | Subject | [patch 21/29] x86: NX bit handling in change_page_attr() |
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2.6.23-stable review patch. If anyone has any objections, please let us know.
------------------ From: Huang, Ying <ying.huang@intel.com>
patch 84e0fdb1754d066dd0a8b257de7299f392d1e727 in mainline.
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 <ying.huang@intel.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- arch/x86_64/mm/pageattr.c | 1 + 1 file changed, 1 insertion(+)
--- a/arch/x86_64/mm/pageattr.c +++ b/arch/x86_64/mm/pageattr.c @@ -148,6 +148,7 @@ __change_page_attr(unsigned long address 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; } -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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