[PATCH] i386: PARAVIRT: Add pagetable accessors to pack and unpack pagetable entries

Add a set of accessors to pack, unpack and modify page table entries
(at all levels).  This allows a paravirt implementation to control the
contents of pgd/pmd/pte entries.  For example, Xen uses this to
convert the (pseudo-)physical address into a machine address when
populating a pagetable entry, and converting back to pphys address
when an entry is read.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Acked-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 38 insertions, 25 deletions

diff --git a/include/asm-i386/pgtable-3level.h b/include/asm-i386/pgtable-3level.h
index 7a2318f38303..be6017f37a91 100644
--- a/include/asm-i386/pgtable-3level.h
+++ b/include/asm-i386/pgtable-3level.h
@@ -42,20 +42,23 @@ static inline int pte_exec_kernel(pte_t pte)
         return pte_x(pte);
 }
 
-#ifndef CONFIG_PARAVIRT
 /* Rules for using set_pte: the pte being assigned *must* be
  * either not present or in a state where the hardware will
  * not attempt to update the pte.  In places where this is
  * not possible, use pte_get_and_clear to obtain the old pte
  * value and then use set_pte to update it.  -ben
  */
-static inline void set_pte(pte_t *ptep, pte_t pte)
+static inline void native_set_pte(pte_t *ptep, pte_t pte)
 {
         ptep->pte_high = pte.pte_high;
         smp_wmb();
         ptep->pte_low = pte.pte_low;
 }
-#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
+static inline void native_set_pte_at(struct mm_struct *mm, unsigned long addr,
+                                     pte_t *ptep , pte_t pte)
+{
+        native_set_pte(ptep, pte);
+}
 
 /*
  * Since this is only called on user PTEs, and the page fault handler
@@ -63,7 +66,8 @@ static inline void set_pte(pte_t *ptep, pte_t pte)
  * we are justified in merely clearing the PTE present bit, followed
  * by a set.  The ordering here is important.
  */
-static inline void set_pte_present(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte)
+static inline void native_set_pte_present(struct mm_struct *mm, unsigned long addr,
+                                          pte_t *ptep, pte_t pte)
 {
         ptep->pte_low = 0;
         smp_wmb();
@@ -72,32 +76,48 @@ static inline void set_pte_present(struct mm_struct *mm, unsigned long addr, pte
         ptep->pte_low = pte.pte_low;
 }
 
-#define set_pte_atomic(pteptr,pteval) \
-                set_64bit((unsigned long long *)(pteptr),pte_val(pteval))
-#define set_pmd(pmdptr,pmdval) \
-                set_64bit((unsigned long long *)(pmdptr),pmd_val(pmdval))
-#define set_pud(pudptr,pudval) \
-                (*(pudptr) = (pudval))
+static inline void native_set_pte_atomic(pte_t *ptep, pte_t pte)
+{
+        set_64bit((unsigned long long *)(ptep),native_pte_val(pte));
+}
+static inline void native_set_pmd(pmd_t *pmdp, pmd_t pmd)
+{
+        set_64bit((unsigned long long *)(pmdp),native_pmd_val(pmd));
+}
+static inline void native_set_pud(pud_t *pudp, pud_t pud)
+{
+        *pudp = pud;
+}
 
 /*
  * For PTEs and PDEs, we must clear the P-bit first when clearing a page table
  * entry, so clear the bottom half first and enforce ordering with a compiler
  * barrier.
  */
-static inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
+static inline void native_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 {
         ptep->pte_low = 0;
         smp_wmb();
         ptep->pte_high = 0;
 }
 
-static inline void pmd_clear(pmd_t *pmd)
+static inline void native_pmd_clear(pmd_t *pmd)
 {
         u32 *tmp = (u32 *)pmd;
         *tmp = 0;
         smp_wmb();
         *(tmp + 1) = 0;
 }
+
+#ifndef CONFIG_PARAVIRT
+#define set_pte(ptep, pte)                      native_set_pte(ptep, pte)
+#define set_pte_at(mm, addr, ptep, pte)         native_set_pte_at(mm, addr, ptep, pte)
+#define set_pte_present(mm, addr, ptep, pte)    native_set_pte_present(mm, addr, ptep, pte)
+#define set_pte_atomic(ptep, pte)               native_set_pte_atomic(ptep, pte)
+#define set_pmd(pmdp, pmd)                      native_set_pmd(pmdp, pmd)
+#define set_pud(pudp, pud)                      native_set_pud(pudp, pud)
+#define pte_clear(mm, addr, ptep)               native_pte_clear(mm, addr, ptep)
+#define pmd_clear(pmd)                          native_pmd_clear(pmd)
 #endif
 
 /*
@@ -119,7 +139,7 @@ static inline void pud_clear (pud_t * pud) { }
 #define pmd_offset(pud, address) ((pmd_t *) pud_page(*(pud)) + \
                         pmd_index(address))
 
-static inline pte_t raw_ptep_get_and_clear(pte_t *ptep)
+static inline pte_t native_ptep_get_and_clear(pte_t *ptep)
 {
         pte_t res;
 
@@ -146,28 +166,21 @@ static inline int pte_none(pte_t pte)
 
 static inline unsigned long pte_pfn(pte_t pte)
 {
-        return (pte.pte_low >> PAGE_SHIFT) |
-                (pte.pte_high << (32 - PAGE_SHIFT));
+        return pte_val(pte) >> PAGE_SHIFT;
 }
 
 extern unsigned long long __supported_pte_mask;
 
 static inline pte_t pfn_pte(unsigned long page_nr, pgprot_t pgprot)
 {
-        pte_t pte;
-
-        pte.pte_high = (page_nr >> (32 - PAGE_SHIFT)) | \
-                                        (pgprot_val(pgprot) >> 32);
-        pte.pte_high &= (__supported_pte_mask >> 32);
-        pte.pte_low = ((page_nr << PAGE_SHIFT) | pgprot_val(pgprot)) & \
-                                                        __supported_pte_mask;
-        return pte;
+        return __pte((((unsigned long long)page_nr << PAGE_SHIFT) |
+                      pgprot_val(pgprot)) & __supported_pte_mask);
 }
 
 static inline pmd_t pfn_pmd(unsigned long page_nr, pgprot_t pgprot)
 {
-        return __pmd((((unsigned long long)page_nr << PAGE_SHIFT) | \
-                        pgprot_val(pgprot)) & __supported_pte_mask);
+        return __pmd((((unsigned long long)page_nr << PAGE_SHIFT) |
+                      pgprot_val(pgprot)) & __supported_pte_mask);
 }
 
 /*