fedora core 6 1.2949 + vserver 2.2.0

[linux-2.6.git] / include / asm-generic / pgtable.h

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index c2059a3..9d774d0 100644 (file)
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -1,6 +1,8 @@
 #ifndef _ASM_GENERIC_PGTABLE_H
 #define _ASM_GENERIC_PGTABLE_H
 
+#ifndef __ASSEMBLY__
+
 #ifndef __HAVE_ARCH_PTEP_ESTABLISH
 /*
  * Establish a new mapping:
@@ -13,19 +15,11 @@
  * Note: the old pte is known to not be writable, so we don't need to
  * worry about dirty bits etc getting lost.
  */
-#ifndef __HAVE_ARCH_SET_PTE_ATOMIC
 #define ptep_establish(__vma, __address, __ptep, __entry)              \
 do {                                                                   \
        set_pte_at((__vma)->vm_mm, (__address), __ptep, __entry);       \
        flush_tlb_page(__vma, __address);                               \
 } while (0)
-#else /* __HAVE_ARCH_SET_PTE_ATOMIC */
-#define ptep_establish(__vma, __address, __ptep, __entry)              \
-do {                                                                   \
-       set_pte_atomic(__ptep, __entry);                                \
-       flush_tlb_page(__vma, __address);                               \
-} while (0)
-#endif /* __HAVE_ARCH_SET_PTE_ATOMIC */
 #endif
 
 #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
@@ -110,8 +104,13 @@ do {                                                                         \
 })
 #endif
 
-#ifndef __HAVE_ARCH_PTE_CLEAR_FULL
-#define pte_clear_full(__mm, __address, __ptep, __full)                        \
+/*
+ * Some architectures may be able to avoid expensive synchronization
+ * primitives when modifications are made to PTE's which are already
+ * not present, or in the process of an address space destruction.
+ */
+#ifndef __HAVE_ARCH_PTE_CLEAR_NOT_PRESENT_FULL
+#define pte_clear_not_present_full(__mm, __address, __ptep, __full)    \
 do {                                                                   \
        pte_clear((__mm), (__address), (__ptep));                       \
 } while (0)
@@ -163,6 +162,26 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres
 #define move_pte(pte, prot, old_addr, new_addr)        (pte)
 #endif
 
+/*
+ * A facility to provide lazy MMU batching.  This allows PTE updates and
+ * page invalidations to be delayed until a call to leave lazy MMU mode
+ * is issued.  Some architectures may benefit from doing this, and it is
+ * beneficial for both shadow and direct mode hypervisors, which may batch
+ * the PTE updates which happen during this window.  Note that using this
+ * interface requires that read hazards be removed from the code.  A read
+ * hazard could result in the direct mode hypervisor case, since the actual
+ * write to the page tables may not yet have taken place, so reads though
+ * a raw PTE pointer after it has been modified are not guaranteed to be
+ * up to date.  This mode can only be entered and left under the protection of
+ * the page table locks for all page tables which may be modified.  In the UP
+ * case, this is required so that preemption is disabled, and in the SMP case,
+ * it must synchronize the delayed page table writes properly on other CPUs.
+ */
+#ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE
+#define arch_enter_lazy_mmu_mode()     do {} while (0)
+#define arch_leave_lazy_mmu_mode()     do {} while (0)
+#endif
+
 /*
  * When walking page tables, get the address of the next boundary,
  * or the end address of the range if that comes earlier.  Although no
@@ -188,7 +207,6 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres
 })
 #endif
 
-#ifndef __ASSEMBLY__
 /*
  * When walking page tables, we usually want to skip any p?d_none entries;
  * and any p?d_bad entries - reporting the error before resetting to none.