Merge remote-tracking branch 'origin/next' into kvm-ppc-next

[linux-drm-fsl-dcu.git] / arch / powerpc / include / asm / kvm_book3s_64.h

diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h
index 154ba3f6b7a9afca98fc8fa1860a7f4635900060..86d638a3b359e1d0f8e03c09c08adafcf9a7aa28 100644 (file)
--- a/arch/powerpc/include/asm/kvm_book3s_64.h
+++ b/arch/powerpc/include/asm/kvm_book3s_64.h
@@ -159,36 +159,46 @@ static inline int hpte_cache_flags_ok(unsigned long ptel, unsigned long io_type)
 }
 
 /*
- * Lock and read a linux PTE.  If it's present and writable, atomically
- * set dirty and referenced bits and return the PTE, otherwise return 0.
+ * If it's present and writable, atomically set dirty and referenced bits and
+ * return the PTE, otherwise return 0. If we find a transparent hugepage
+ * and if it is marked splitting we return 0;
  */
-static inline pte_t kvmppc_read_update_linux_pte(pte_t *p, int writing)
+static inline pte_t kvmppc_read_update_linux_pte(pte_t *ptep, int writing,
+                                                unsigned int hugepage)
 {
-       pte_t pte, tmp;
-
-       /* wait until _PAGE_BUSY is clear then set it atomically */
-       __asm__ __volatile__ (
-               "1:     ldarx   %0,0,%3\n"
-               "       andi.   %1,%0,%4\n"
-               "       bne-    1b\n"
-               "       ori     %1,%0,%4\n"
-               "       stdcx.  %1,0,%3\n"
-               "       bne-    1b"
-               : "=&r" (pte), "=&r" (tmp), "=m" (*p)
-               : "r" (p), "i" (_PAGE_BUSY)
-               : "cc");
-
-       if (pte_present(pte)) {
-               pte = pte_mkyoung(pte);
-               if (writing && pte_write(pte))
-                       pte = pte_mkdirty(pte);
-       }
+       pte_t old_pte, new_pte = __pte(0);
+
+       while (1) {
+               old_pte = pte_val(*ptep);
+               /*
+                * wait until _PAGE_BUSY is clear then set it atomically
+                */
+               if (unlikely(old_pte & _PAGE_BUSY)) {
+                       cpu_relax();
+                       continue;
+               }
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+               /* If hugepage and is trans splitting return None */
+               if (unlikely(hugepage &&
+                            pmd_trans_splitting(pte_pmd(old_pte))))
+                       return __pte(0);
+#endif
+               /* If pte is not present return None */
+               if (unlikely(!(old_pte & _PAGE_PRESENT)))
+                       return __pte(0);
 
-       *p = pte;       /* clears _PAGE_BUSY */
+               new_pte = pte_mkyoung(old_pte);
+               if (writing && pte_write(old_pte))
+                       new_pte = pte_mkdirty(new_pte);
 
-       return pte;
+               if (old_pte == __cmpxchg_u64((unsigned long *)ptep, old_pte,
+                                            new_pte))
+                       break;
+       }
+       return new_pte;
 }
 
+
 /* Return HPTE cache control bits corresponding to Linux pte bits */
 static inline unsigned long hpte_cache_bits(unsigned long pte_val)
 {