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authorJohannes Weiner <hannes@cmpxchg.org>2011-01-13 15:47:01 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-01-13 17:32:44 -0800
commitf2d6bfe9ff0acec30b713614260e78b03d20e909 (patch)
tree835dd9f4167513d94ae542cf92347ea98bff5ddc /arch/x86/include/asm/pgtable-3level.h
parent5f24ce5fd34c3ca1b3d10d30da754732da64d5c0 (diff)
thp: add x86 32bit support
Add support for transparent hugepages to x86 32bit. Share the same VM_ bitflag for VM_MAPPED_COPY. mm/nommu.c will never support transparent hugepages. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/x86/include/asm/pgtable-3level.h')
-rw-r--r--arch/x86/include/asm/pgtable-3level.h23
1 files changed, 23 insertions, 0 deletions
diff --git a/arch/x86/include/asm/pgtable-3level.h b/arch/x86/include/asm/pgtable-3level.h
index 177b0165ea0..94b979d1b58 100644
--- a/arch/x86/include/asm/pgtable-3level.h
+++ b/arch/x86/include/asm/pgtable-3level.h
@@ -104,6 +104,29 @@ static inline pte_t native_ptep_get_and_clear(pte_t *ptep)
#define native_ptep_get_and_clear(xp) native_local_ptep_get_and_clear(xp)
#endif
+#ifdef CONFIG_SMP
+union split_pmd {
+ struct {
+ u32 pmd_low;
+ u32 pmd_high;
+ };
+ pmd_t pmd;
+};
+static inline pmd_t native_pmdp_get_and_clear(pmd_t *pmdp)
+{
+ union split_pmd res, *orig = (union split_pmd *)pmdp;
+
+ /* xchg acts as a barrier before setting of the high bits */
+ res.pmd_low = xchg(&orig->pmd_low, 0);
+ res.pmd_high = orig->pmd_high;
+ orig->pmd_high = 0;
+
+ return res.pmd;
+}
+#else
+#define native_pmdp_get_and_clear(xp) native_local_pmdp_get_and_clear(xp)
+#endif
+
/*
* Bits 0, 6 and 7 are taken in the low part of the pte,
* put the 32 bits of offset into the high part.