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authorHuang, Ying <ying.huang@intel.com>2007-10-17 18:04:35 +0200
committerThomas Gleixner <tglx@inhelltoy.tec.linutronix.de>2007-10-17 20:15:43 +0200
commit84e0fdb1754d066dd0a8b257de7299f392d1e727 (patch)
treee1ce3339ba46cbe066e348222e9446cb5ad109f2 /arch
parent87cde760abfa019b5e368186f893cf673d227632 (diff)
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>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/mm/pageattr_64.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/mm/pageattr_64.c b/arch/x86/mm/pageattr_64.c
index 10b9809ce82..93d795d7c2a 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;
}