Merge tag 'v2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

[mv-sheeva.git] / arch / x86 / include / asm / pgtable-3level.h

diff --git a/arch/x86/include/asm/pgtable-3level.h b/arch/x86/include/asm/pgtable-3level.h
index 177b0165ea01fa8aeeb1f8749252d422de52b3a6..94b979d1b58dbcef07dc7b02c3e9b1e94e71926d 100644 (file)
--- 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.