x86: pgtable: unify pte accessors

Make various pte accessors common.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 109 insertions, 1 deletions

diff --git a/include/asm-x86/pgtable.h b/include/asm-x86/pgtable.h
index 6452286e71a..62fa856c249 100644
--- a/include/asm-x86/pgtable.h
+++ b/include/asm-x86/pgtable.h
@@ -116,6 +116,7 @@ extern unsigned long long __PAGE_KERNEL, __PAGE_KERNEL_EXEC;
 #define __S111	PAGE_SHARED_EXEC
 
 #ifndef __ASSEMBLY__
+
 /*
  * The following only work if pte_present() is true.
  * Undefined behaviour if not..
@@ -169,7 +170,6 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 	return __pte(val);
 }
 
-
 #endif	/* __ASSEMBLY__ */
 
 #ifdef CONFIG_X86_32
@@ -178,4 +178,112 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 # include "pgtable_64.h"
 #endif
 
+#ifndef __ASSEMBLY__
+
+#ifndef CONFIG_PARAVIRT
+/*
+ * Rules for using pte_update - it must be called after any PTE update which
+ * has not been done using the set_pte / clear_pte interfaces.  It is used by
+ * shadow mode hypervisors to resynchronize the shadow page tables.  Kernel PTE
+ * updates should either be sets, clears, or set_pte_atomic for P->P
+ * transitions, which means this hook should only be called for user PTEs.
+ * This hook implies a P->P protection or access change has taken place, which
+ * requires a subsequent TLB flush.  The notification can optionally be delayed
+ * until the TLB flush event by using the pte_update_defer form of the
+ * interface, but care must be taken to assure that the flush happens while
+ * still holding the same page table lock so that the shadow and primary pages
+ * do not become out of sync on SMP.
+ */
+#define pte_update(mm, addr, ptep)		do { } while (0)
+#define pte_update_defer(mm, addr, ptep)	do { } while (0)
+#endif
+
+/* local pte updates need not use xchg for locking */
+static inline pte_t native_local_ptep_get_and_clear(pte_t *ptep)
+{
+	pte_t res = *ptep;
+
+	/* Pure native function needs no input for mm, addr */
+	native_pte_clear(NULL, 0, ptep);
+	return res;
+}
+
+/*
+ * We only update the dirty/accessed state if we set
+ * the dirty bit by hand in the kernel, since the hardware
+ * will do the accessed bit for us, and we don't want to
+ * race with other CPU's that might be updating the dirty
+ * bit at the same time.
+ */
+#define  __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
+#define ptep_set_access_flags(vma, address, ptep, entry, dirty)		\
+({									\
+	int __changed = !pte_same(*(ptep), entry);			\
+	if (__changed && dirty) {					\
+		*ptep = entry;						\
+		pte_update_defer((vma)->vm_mm, (address), (ptep));	\
+		flush_tlb_page(vma, address);				\
+	}								\
+	__changed;							\
+})
+
+#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
+#define ptep_test_and_clear_young(vma, addr, ptep) ({			\
+	int __ret = 0;							\
+	if (pte_young(*(ptep)))						\
+		__ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,		\
+					   &(ptep)->pte);		\
+	if (__ret)							\
+		pte_update((vma)->vm_mm, addr, ptep);			\
+	__ret;								\
+})
+
+#define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
+#define ptep_clear_flush_young(vma, address, ptep)			\
+({									\
+	int __young;							\
+	__young = ptep_test_and_clear_young((vma), (address), (ptep));	\
+	if (__young)							\
+		flush_tlb_page(vma, address);				\
+	__young;							\
+})
+
+#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
+static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
+{
+	pte_t pte = native_ptep_get_and_clear(ptep);
+	pte_update(mm, addr, ptep);
+	return pte;
+}
+
+#define __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
+static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm, unsigned long addr, pte_t *ptep, int full)
+{
+	pte_t pte;
+	if (full) {
+		/*
+		 * Full address destruction in progress; paravirt does not
+		 * care about updates and native needs no locking
+		 */
+		pte = native_local_ptep_get_and_clear(ptep);
+	} else {
+		pte = ptep_get_and_clear(mm, addr, ptep);
+	}
+	return pte;
+}
+
+#define __HAVE_ARCH_PTEP_SET_WRPROTECT
+static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
+{
+	clear_bit(_PAGE_BIT_RW, &ptep->pte);
+	pte_update(mm, addr, ptep);
+}
+
+#ifndef CONFIG_PARAVIRT
+#define pte_clear(mm, addr, ptep)		native_pte_clear(mm, addr, ptep)
+#endif	/* !CONFIG_PARAVIRT */
+
+#include <asm-generic/pgtable.h>
+#endif	/* __ASSEMBLY__ */
+
 #endif	/* _ASM_X86_PGTABLE_H */