diff options
| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2013-11-19 15:17:50 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-11-19 14:24:50 +0100 |
| commit | fd8526ad14c182605e42b64646344b95befd9f94 (patch) | |
| tree | e27277373aa64ed7d7d45f68c86eefdd07f14510 /arch/x86/include/asm/page.h | |
| parent | 5305ca10e7f44333e46c1ce57fb87306cb437891 (diff) | |
x86/mm: Implement ASLR for hugetlb mappings
Matthew noticed that hugetlb mappings don't participate in ASLR on x86-64:
% for i in `seq 3`; do
> tools/testing/selftests/vm/map_hugetlb | grep address
> done
Returned address is 0x2aaaaac00000
Returned address is 0x2aaaaac00000
Returned address is 0x2aaaaac00000
/proc/PID/maps entries for the mapping are always the same
(except inode number):
2aaaaac00000-2aaabac00000 rw-p 00000000 00:0c 8200 /anon_hugepage (deleted)
2aaaaac00000-2aaabac00000 rw-p 00000000 00:0c 256 /anon_hugepage (deleted)
2aaaaac00000-2aaabac00000 rw-p 00000000 00:0c 7180 /anon_hugepage (deleted)
The reason is the generic hugetlb_get_unmapped_area() function
which is used on x86-64. It doesn't support randomization and
use bottom-up unmapped area lookup, instead of usual top-down
on x86-64.
x86 has arch-specific hugetlb_get_unmapped_area(), but it's used
only on x86-32.
Let's use arch-specific hugetlb_get_unmapped_area() on x86-64
too. That adds ASLR and switches hugetlb mappings to use top-down
unmapped area lookup:
% for i in `seq 3`; do
> tools/testing/selftests/vm/map_hugetlb | grep address
> done
Returned address is 0x7f4f08a00000
Returned address is 0x7fdda4200000
Returned address is 0x7febe0000000
/proc/PID/maps entries:
7f4f08a00000-7f4f18a00000 rw-p 00000000 00:0c 1168 /anon_hugepage (deleted)
7fdda4200000-7fddb4200000 rw-p 00000000 00:0c 7092 /anon_hugepage (deleted)
7febe0000000-7febf0000000 rw-p 00000000 00:0c 7183 /anon_hugepage (deleted)
Unmapped area lookup policy for hugetlb mappings is consistent
with normal mappings now -- the only difference is alignment
requirements for huge pages.
libhugetlbfs test-suite didn't detect any regressions with the
patch applied (although it shows few failures on my machine
regardless the patch).
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mel Gorman <mgorman@suse.de>
Link: http://lkml.kernel.org/r/20131119131750.EA45CE0090@blue.fi.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/asm/page.h')
| -rw-r--r-- | arch/x86/include/asm/page.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h index c87892442e53..775873d3be55 100644 --- a/arch/x86/include/asm/page.h +++ b/arch/x86/include/asm/page.h @@ -71,6 +71,7 @@ extern bool __virt_addr_valid(unsigned long kaddr); #include <asm-generic/getorder.h> #define __HAVE_ARCH_GATE_AREA 1 +#define HAVE_ARCH_HUGETLB_UNMAPPED_AREA #endif /* __KERNEL__ */ #endif /* _ASM_X86_PAGE_H */ |