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| author | Huang, Ying <ying.huang@intel.com> | 2007-10-17 18:04:35 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2007-11-26 09:42:31 -0800 |
| commit | 5b7e28db04cb42b8f8b81c6ae61a7d77bddc373a (patch) | |
| tree | 5ccef0309dbc2abaf44e4bce3525a3506c4aa360 | |
| parent | 420b463a199d10fc89f41f24fb8c60ed0181b4ad (diff) | |
| download | lwn-5b7e28db04cb42b8f8b81c6ae61a7d77bddc373a.tar.gz lwn-5b7e28db04cb42b8f8b81c6ae61a7d77bddc373a.zip | |
x86: NX bit handling in change_page_attr()
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>
| -rw-r--r-- | arch/x86_64/mm/pageattr.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86_64/mm/pageattr.c b/arch/x86_64/mm/pageattr.c index 0416ffb8e36c..eff3b22a2fb7 100644 --- a/arch/x86_64/mm/pageattr.c +++ b/arch/x86_64/mm/pageattr.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; } |