25 files changed, 168 insertions, 49 deletions

diff --git a/include/asm-alpha/pgtable.h b/include/asm-alpha/pgtable.h
index 99037b032357..05ce5fba43e3 100644
--- a/include/asm-alpha/pgtable.h
+++ b/include/asm-alpha/pgtable.h
@@ -268,6 +268,7 @@ extern inline int pte_write(pte_t pte)		{ return !(pte_val(pte) & _PAGE_FOW); }
 extern inline int pte_dirty(pte_t pte)          { return pte_val(pte) & _PAGE_DIRTY; }
 extern inline int pte_young(pte_t pte)          { return pte_val(pte) & _PAGE_ACCESSED; }
 extern inline int pte_file(pte_t pte)           { return pte_val(pte) & _PAGE_FILE; }
+extern inline int pte_special(pte_t pte)        { return 0; }
 
 extern inline pte_t pte_wrprotect(pte_t pte)    { pte_val(pte) |= _PAGE_FOW; return pte; }
 extern inline pte_t pte_mkclean(pte_t pte)      { pte_val(pte) &= ~(__DIRTY_BITS); return pte; }
@@ -275,6 +276,7 @@ extern inline pte_t pte_mkold(pte_t pte)	{ pte_val(pte) &= ~(__ACCESS_BITS); ret
 extern inline pte_t pte_mkwrite(pte_t pte)      { pte_val(pte) &= ~_PAGE_FOW; return pte; }
 extern inline pte_t pte_mkdirty(pte_t pte)      { pte_val(pte) |= __DIRTY_BITS; return pte; }
 extern inline pte_t pte_mkyoung(pte_t pte)      { pte_val(pte) |= __ACCESS_BITS; return pte; }
+extern inline pte_t pte_mkspecial(pte_t pte)    { return pte; }
 
 #define PAGE_DIR_OFFSET(tsk,address) pgd_offset((tsk),(address))
 
diff --git a/include/asm-arm/pgtable.h b/include/asm-arm/pgtable.h
index 5e0182485d8c..5571c13c3f3b 100644
--- a/include/asm-arm/pgtable.h
+++ b/include/asm-arm/pgtable.h
@@ -260,6 +260,7 @@ extern struct page *empty_zero_page;
 #define pte_write(pte)          (pte_val(pte) & L_PTE_WRITE)
 #define pte_dirty(pte)          (pte_val(pte) & L_PTE_DIRTY)
 #define pte_young(pte)          (pte_val(pte) & L_PTE_YOUNG)
+#define pte_special(pte)        (0)
 
 /*
  * The following only works if pte_present() is not true.
@@ -280,6 +281,8 @@ PTE_BIT_FUNC(mkdirty,   |= L_PTE_DIRTY);
 PTE_BIT_FUNC(mkold,     &= ~L_PTE_YOUNG);
 PTE_BIT_FUNC(mkyoung,   |= L_PTE_YOUNG);
 
+static inline pte_t pte_mkspecial(pte_t pte) { return pte; }
+
 /*
  * Mark the prot value as uncacheable and unbufferable.
  */
diff --git a/include/asm-avr32/pgtable.h b/include/asm-avr32/pgtable.h
index 3ae7b548fce7..c0e5e29417df 100644
--- a/include/asm-avr32/pgtable.h
+++ b/include/asm-avr32/pgtable.h
@@ -212,6 +212,10 @@ static inline int pte_young(pte_t pte)
 {
         return pte_val(pte) & _PAGE_ACCESSED;
 }
+static inline int pte_special(pte_t pte)
+{
+        return 0;
+}
 
 /*
  * The following only work if pte_present() is not true.
@@ -252,6 +256,10 @@ static inline pte_t pte_mkyoung(pte_t pte)
         set_pte(&pte, __pte(pte_val(pte) | _PAGE_ACCESSED));
         return pte;
 }
+static inline pte_t pte_mkspecial(pte_t pte)
+{
+        return pte;
+}
 
 #define pmd_none(x)     (!pmd_val(x))
 #define pmd_present(x)  (pmd_val(x) & _PAGE_PRESENT)
diff --git a/include/asm-cris/pgtable.h b/include/asm-cris/pgtable.h
index a2607575681b..4c373624ee97 100644
--- a/include/asm-cris/pgtable.h
+++ b/include/asm-cris/pgtable.h
@@ -115,6 +115,7 @@ static inline int pte_write(pte_t pte)          { return pte_val(pte) & _PAGE_WR
 static inline int pte_dirty(pte_t pte)          { return pte_val(pte) & _PAGE_MODIFIED; }
 static inline int pte_young(pte_t pte)          { return pte_val(pte) & _PAGE_ACCESSED; }
 static inline int pte_file(pte_t pte)           { return pte_val(pte) & _PAGE_FILE; }
+static inline int pte_special(pte_t pte)        { return 0; }
 
 static inline pte_t pte_wrprotect(pte_t pte)
 {
@@ -162,6 +163,7 @@ static inline pte_t pte_mkyoung(pte_t pte)
         }
         return pte;
 }
+static inline pte_t pte_mkspecial(pte_t pte)    { return pte; }
 
 /*
  * Conversion functions: convert a page and protection to a page entry,
diff --git a/include/asm-frv/pgtable.h b/include/asm-frv/pgtable.h
index 4e219046fe42..83c51aba534b 100644
--- a/include/asm-frv/pgtable.h
+++ b/include/asm-frv/pgtable.h
@@ -380,6 +380,7 @@ static inline pmd_t *pmd_offset(pud_t *dir, unsigned long address)
 static inline int pte_dirty(pte_t pte)          { return (pte).pte & _PAGE_DIRTY; }
 static inline int pte_young(pte_t pte)          { return (pte).pte & _PAGE_ACCESSED; }
 static inline int pte_write(pte_t pte)          { return !((pte).pte & _PAGE_WP); }
+static inline int pte_special(pte_t pte)        { return 0; }
 
 static inline pte_t pte_mkclean(pte_t pte)      { (pte).pte &= ~_PAGE_DIRTY; return pte; }
 static inline pte_t pte_mkold(pte_t pte)        { (pte).pte &= ~_PAGE_ACCESSED; return pte; }
@@ -387,6 +388,7 @@ static inline pte_t pte_wrprotect(pte_t pte)	{ (pte).pte |= _PAGE_WP; return pte
 static inline pte_t pte_mkdirty(pte_t pte)      { (pte).pte |= _PAGE_DIRTY; return pte; }
 static inline pte_t pte_mkyoung(pte_t pte)      { (pte).pte |= _PAGE_ACCESSED; return pte; }
 static inline pte_t pte_mkwrite(pte_t pte)      { (pte).pte &= ~_PAGE_WP; return pte; }
+static inline pte_t pte_mkspecial(pte_t pte)    { return pte; }
 
 static inline int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
 {
diff --git a/include/asm-ia64/pgtable.h b/include/asm-ia64/pgtable.h
index ed70862ea247..7a9bff47564f 100644
--- a/include/asm-ia64/pgtable.h
+++ b/include/asm-ia64/pgtable.h
@@ -302,6 +302,8 @@ ia64_phys_addr_valid (unsigned long addr)
 #define pte_dirty(pte)          ((pte_val(pte) & _PAGE_D) != 0)
 #define pte_young(pte)          ((pte_val(pte) & _PAGE_A) != 0)
 #define pte_file(pte)           ((pte_val(pte) & _PAGE_FILE) != 0)
+#define pte_special(pte)        0
+
 /*
  * Note: we convert AR_RWX to AR_RX and AR_RW to AR_R by clearing the 2nd bit in the
  * access rights:
@@ -313,6 +315,7 @@ ia64_phys_addr_valid (unsigned long addr)
 #define pte_mkclean(pte)        (__pte(pte_val(pte) & ~_PAGE_D))
 #define pte_mkdirty(pte)        (__pte(pte_val(pte) | _PAGE_D))
 #define pte_mkhuge(pte)         (__pte(pte_val(pte)))
+#define pte_mkspecial(pte)      (pte)
 
 /*
  * Because ia64's Icache and Dcache is not coherent (on a cpu), we need to
diff --git a/include/asm-m32r/pgtable.h b/include/asm-m32r/pgtable.h
index 86505387be08..e6359c566b50 100644
--- a/include/asm-m32r/pgtable.h
+++ b/include/asm-m32r/pgtable.h
@@ -214,6 +214,11 @@ static inline int pte_file(pte_t pte)
         return pte_val(pte) & _PAGE_FILE;
 }
 
+static inline int pte_special(pte_t pte)
+{
+        return 0;
+}
+
 static inline pte_t pte_mkclean(pte_t pte)
 {
         pte_val(pte) &= ~_PAGE_DIRTY;
@@ -250,6 +255,11 @@ static inline pte_t pte_mkwrite(pte_t pte)
         return pte;
 }
 
+static inline pte_t pte_mkspecial(pte_t pte)
+{
+        return pte;
+}
+
 static inline  int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
 {
         return test_and_clear_bit(_PAGE_BIT_ACCESSED, ptep);
diff --git a/include/asm-m68k/motorola_pgtable.h b/include/asm-m68k/motorola_pgtable.h
index 13135d4821d8..8e9a8a754dde 100644
--- a/include/asm-m68k/motorola_pgtable.h
+++ b/include/asm-m68k/motorola_pgtable.h
@@ -168,6 +168,7 @@ static inline int pte_write(pte_t pte)		{ return !(pte_val(pte) & _PAGE_RONLY);
 static inline int pte_dirty(pte_t pte)          { return pte_val(pte) & _PAGE_DIRTY; }
 static inline int pte_young(pte_t pte)          { return pte_val(pte) & _PAGE_ACCESSED; }
 static inline int pte_file(pte_t pte)           { return pte_val(pte) & _PAGE_FILE; }
+static inline int pte_special(pte_t pte)        { return 0; }
 
 static inline pte_t pte_wrprotect(pte_t pte)    { pte_val(pte) |= _PAGE_RONLY; return pte; }
 static inline pte_t pte_mkclean(pte_t pte)      { pte_val(pte) &= ~_PAGE_DIRTY; return pte; }
@@ -185,6 +186,7 @@ static inline pte_t pte_mkcache(pte_t pte)
         pte_val(pte) = (pte_val(pte) & _CACHEMASK040) | m68k_supervisor_cachemode;
         return pte;
 }
+static inline pte_t pte_mkspecial(pte_t pte)    { return pte; }
 
 #define PAGE_DIR_OFFSET(tsk,address) pgd_offset((tsk),(address))
 
diff --git a/include/asm-m68k/sun3_pgtable.h b/include/asm-m68k/sun3_pgtable.h
index b766fc261bde..f847ec732d62 100644
--- a/include/asm-m68k/sun3_pgtable.h
+++ b/include/asm-m68k/sun3_pgtable.h
@@ -169,6 +169,7 @@ static inline int pte_write(pte_t pte)		{ return pte_val(pte) & SUN3_PAGE_WRITEA
 static inline int pte_dirty(pte_t pte)          { return pte_val(pte) & SUN3_PAGE_MODIFIED; }
 static inline int pte_young(pte_t pte)          { return pte_val(pte) & SUN3_PAGE_ACCESSED; }
 static inline int pte_file(pte_t pte)           { return pte_val(pte) & SUN3_PAGE_ACCESSED; }
+static inline int pte_special(pte_t pte)        { return 0; }
 
 static inline pte_t pte_wrprotect(pte_t pte)    { pte_val(pte) &= ~SUN3_PAGE_WRITEABLE; return pte; }
 static inline pte_t pte_mkclean(pte_t pte)      { pte_val(pte) &= ~SUN3_PAGE_MODIFIED; return pte; }
@@ -181,6 +182,7 @@ static inline pte_t pte_mknocache(pte_t pte)	{ pte_val(pte) |= SUN3_PAGE_NOCACHE
 //static inline pte_t pte_mkcache(pte_t pte)    { pte_val(pte) &= SUN3_PAGE_NOCACHE; return pte; }
 // until then, use:
 static inline pte_t pte_mkcache(pte_t pte)      { return pte; }
+static inline pte_t pte_mkspecial(pte_t pte)    { return pte; }
 
 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
 extern pgd_t kernel_pg_dir[PTRS_PER_PGD];
diff --git a/include/asm-mips/pgtable.h b/include/asm-mips/pgtable.h
index 17a7703a2969..782221e57c0a 100644
--- a/include/asm-mips/pgtable.h
+++ b/include/asm-mips/pgtable.h
@@ -285,6 +285,8 @@ static inline pte_t pte_mkyoung(pte_t pte)
         return pte;
 }
 #endif
+static inline int pte_special(pte_t pte)        { return 0; }
+static inline pte_t pte_mkspecial(pte_t pte)    { return pte; }
 
 /*
  * Macro to make mark a page protection value as "uncacheable".  Note
diff --git a/include/asm-mn10300/pgtable.h b/include/asm-mn10300/pgtable.h
index 375c4941deda..6dc30fc827c4 100644
--- a/include/asm-mn10300/pgtable.h
+++ b/include/asm-mn10300/pgtable.h
@@ -224,6 +224,7 @@ static inline int pte_read(pte_t pte)	{ return pte_val(pte) & __PAGE_PROT_USER;
 static inline int pte_dirty(pte_t pte)  { return pte_val(pte) & _PAGE_DIRTY; }
 static inline int pte_young(pte_t pte)  { return pte_val(pte) & _PAGE_ACCESSED; }
 static inline int pte_write(pte_t pte)  { return pte_val(pte) & __PAGE_PROT_WRITE; }
+static inline int pte_special(pte_t pte){ return 0; }
 
 /*
  * The following only works if pte_present() is not true.
@@ -265,6 +266,8 @@ static inline pte_t pte_mkwrite(pte_t pte)
         return pte;
 }
 
+static inline pte_t pte_mkspecial(pte_t pte)    { return pte; }
+
 #define pte_ERROR(e) \
         printk(KERN_ERR "%s:%d: bad pte %08lx.\n", \
                __FILE__, __LINE__, pte_val(e))
diff --git a/include/asm-parisc/pgtable.h b/include/asm-parisc/pgtable.h
index dc86adbec916..470a4b88124d 100644
--- a/include/asm-parisc/pgtable.h
+++ b/include/asm-parisc/pgtable.h
@@ -323,6 +323,7 @@ static inline int pte_dirty(pte_t pte)		{ return pte_val(pte) & _PAGE_DIRTY; }
 static inline int pte_young(pte_t pte)          { return pte_val(pte) & _PAGE_ACCESSED; }
 static inline int pte_write(pte_t pte)          { return pte_val(pte) & _PAGE_WRITE; }
 static inline int pte_file(pte_t pte)           { return pte_val(pte) & _PAGE_FILE; }
+static inline int pte_special(pte_t pte)        { return 0; }
 
 static inline pte_t pte_mkclean(pte_t pte)      { pte_val(pte) &= ~_PAGE_DIRTY; return pte; }
 static inline pte_t pte_mkold(pte_t pte)        { pte_val(pte) &= ~_PAGE_ACCESSED; return pte; }
@@ -330,6 +331,7 @@ static inline pte_t pte_wrprotect(pte_t pte)	{ pte_val(pte) &= ~_PAGE_WRITE; ret
 static inline pte_t pte_mkdirty(pte_t pte)      { pte_val(pte) |= _PAGE_DIRTY; return pte; }
 static inline pte_t pte_mkyoung(pte_t pte)      { pte_val(pte) |= _PAGE_ACCESSED; return pte; }
 static inline pte_t pte_mkwrite(pte_t pte)      { pte_val(pte) |= _PAGE_WRITE; return pte; }
+static inline pte_t pte_mkspecial(pte_t pte)    { return pte; }
 
 /*
  * Conversion functions: convert a page and protection to a page entry,
diff --git a/include/asm-powerpc/pgtable-ppc32.h b/include/asm-powerpc/pgtable-ppc32.h
index daea7692d070..7c97b5a08d08 100644
--- a/include/asm-powerpc/pgtable-ppc32.h
+++ b/include/asm-powerpc/pgtable-ppc32.h
@@ -504,6 +504,7 @@ static inline int pte_write(pte_t pte)		{ return pte_val(pte) & _PAGE_RW; }
 static inline int pte_dirty(pte_t pte)          { return pte_val(pte) & _PAGE_DIRTY; }
 static inline int pte_young(pte_t pte)          { return pte_val(pte) & _PAGE_ACCESSED; }
 static inline int pte_file(pte_t pte)           { return pte_val(pte) & _PAGE_FILE; }
+static inline int pte_special(pte_t pte)        { return 0; }
 
 static inline void pte_uncache(pte_t pte)       { pte_val(pte) |= _PAGE_NO_CACHE; }
 static inline void pte_cache(pte_t pte)         { pte_val(pte) &= ~_PAGE_NO_CACHE; }
@@ -521,6 +522,8 @@ static inline pte_t pte_mkdirty(pte_t pte) {
         pte_val(pte) |= _PAGE_DIRTY; return pte; }
 static inline pte_t pte_mkyoung(pte_t pte) {
         pte_val(pte) |= _PAGE_ACCESSED; return pte; }
+static inline pte_t pte_mkspecial(pte_t pte) {
+        return pte; }
 
 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 {
diff --git a/include/asm-powerpc/pgtable-ppc64.h b/include/asm-powerpc/pgtable-ppc64.h
index dd4c26dc57d2..27f18695f7d6 100644
--- a/include/asm-powerpc/pgtable-ppc64.h
+++ b/include/asm-powerpc/pgtable-ppc64.h
@@ -239,6 +239,7 @@ static inline int pte_write(pte_t pte) { return pte_val(pte) & _PAGE_RW;}
 static inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY;}
 static inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED;}
 static inline int pte_file(pte_t pte) { return pte_val(pte) & _PAGE_FILE;}
+static inline int pte_special(pte_t pte) { return 0; }
 
 static inline void pte_uncache(pte_t pte) { pte_val(pte) |= _PAGE_NO_CACHE; }
 static inline void pte_cache(pte_t pte)   { pte_val(pte) &= ~_PAGE_NO_CACHE; }
@@ -257,6 +258,8 @@ static inline pte_t pte_mkyoung(pte_t pte) {
         pte_val(pte) |= _PAGE_ACCESSED; return pte; }
 static inline pte_t pte_mkhuge(pte_t pte) {
         return pte; }
+static inline pte_t pte_mkspecial(pte_t pte) {
+        return pte; }
 
 /* Atomic PTE updates */
 static inline unsigned long pte_update(struct mm_struct *mm,
diff --git a/include/asm-ppc/pgtable.h b/include/asm-ppc/pgtable.h
index 70435d32129a..55f9d38e3bf8 100644
--- a/include/asm-ppc/pgtable.h
+++ b/include/asm-ppc/pgtable.h
@@ -483,6 +483,7 @@ static inline int pte_write(pte_t pte)		{ return pte_val(pte) & _PAGE_RW; }
 static inline int pte_dirty(pte_t pte)          { return pte_val(pte) & _PAGE_DIRTY; }
 static inline int pte_young(pte_t pte)          { return pte_val(pte) & _PAGE_ACCESSED; }
 static inline int pte_file(pte_t pte)           { return pte_val(pte) & _PAGE_FILE; }
+static inline int pte_special(pte_t pte)        { return 0; }
 
 static inline void pte_uncache(pte_t pte)       { pte_val(pte) |= _PAGE_NO_CACHE; }
 static inline void pte_cache(pte_t pte)         { pte_val(pte) &= ~_PAGE_NO_CACHE; }
@@ -500,6 +501,8 @@ static inline pte_t pte_mkdirty(pte_t pte) {
         pte_val(pte) |= _PAGE_DIRTY; return pte; }
 static inline pte_t pte_mkyoung(pte_t pte) {
         pte_val(pte) |= _PAGE_ACCESSED; return pte; }
+static inline pte_t pte_mkspecial(pte_t pte) {
+        return pte; }
 
 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 {
diff --git a/include/asm-s390/pgtable.h b/include/asm-s390/pgtable.h
index 4c0698c0dda5..76e8a7904e8a 100644
--- a/include/asm-s390/pgtable.h
+++ b/include/asm-s390/pgtable.h
@@ -518,6 +518,11 @@ static inline int pte_file(pte_t pte)
         return (pte_val(pte) & mask) == _PAGE_TYPE_FILE;
 }
 
+static inline int pte_special(pte_t pte)
+{
+        return 0;
+}
+
 #define __HAVE_ARCH_PTE_SAME
 #define pte_same(a,b)  (pte_val(a) == pte_val(b))
 
@@ -715,6 +720,11 @@ static inline pte_t pte_mkyoung(pte_t pte)
         return pte;
 }
 
+static inline pte_t pte_mkspecial(pte_t pte)
+{
+        return pte;
+}
+
 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
 static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
                                             unsigned long addr, pte_t *ptep)
diff --git a/include/asm-sh/pgtable_32.h b/include/asm-sh/pgtable_32.h
index 3e3557c53c55..cbc731d35c25 100644
--- a/include/asm-sh/pgtable_32.h
+++ b/include/asm-sh/pgtable_32.h
@@ -326,6 +326,7 @@ static inline void set_pte(pte_t *ptep, pte_t pte)
 #define pte_dirty(pte)          ((pte).pte_low & _PAGE_DIRTY)
 #define pte_young(pte)          ((pte).pte_low & _PAGE_ACCESSED)
 #define pte_file(pte)           ((pte).pte_low & _PAGE_FILE)
+#define pte_special(pte)        (0)
 
 #ifdef CONFIG_X2TLB
 #define pte_write(pte)          ((pte).pte_high & _PAGE_EXT_USER_WRITE)
@@ -356,6 +357,8 @@ PTE_BIT_FUNC(low, mkdirty, |= _PAGE_DIRTY);
 PTE_BIT_FUNC(low, mkold, &= ~_PAGE_ACCESSED);
 PTE_BIT_FUNC(low, mkyoung, |= _PAGE_ACCESSED);
 
+static inline pte_t pte_mkspecial(pte_t pte) { return pte; }
+
 /*
  * Macro and implementation to make a page protection as uncachable.
  */
diff --git a/include/asm-sh/pgtable_64.h b/include/asm-sh/pgtable_64.h
index f9dd9d311441..c78990cda557 100644
--- a/include/asm-sh/pgtable_64.h
+++ b/include/asm-sh/pgtable_64.h
@@ -254,10 +254,11 @@ extern void __handle_bad_pmd_kernel(pmd_t * pmd);
 /*
  * The following have defined behavior only work if pte_present() is true.
  */
-static inline int pte_dirty(pte_t pte){ return pte_val(pte) & _PAGE_DIRTY; }
-static inline int pte_young(pte_t pte){ return pte_val(pte) & _PAGE_ACCESSED; }
-static inline int pte_file(pte_t pte) { return pte_val(pte) & _PAGE_FILE; }
-static inline int pte_write(pte_t pte){ return pte_val(pte) & _PAGE_WRITE; }
+static inline int pte_dirty(pte_t pte)  { return pte_val(pte) & _PAGE_DIRTY; }
+static inline int pte_young(pte_t pte)  { return pte_val(pte) & _PAGE_ACCESSED; }
+static inline int pte_file(pte_t pte)   { return pte_val(pte) & _PAGE_FILE; }
+static inline int pte_write(pte_t pte)  { return pte_val(pte) & _PAGE_WRITE; }
+static inline int pte_special(pte_t pte){ return 0; }
 
 static inline pte_t pte_wrprotect(pte_t pte)    { set_pte(&pte, __pte(pte_val(pte) & ~_PAGE_WRITE)); return pte; }
 static inline pte_t pte_mkclean(pte_t pte)      { set_pte(&pte, __pte(pte_val(pte) & ~_PAGE_DIRTY)); return pte; }
@@ -266,6 +267,7 @@ static inline pte_t pte_mkwrite(pte_t pte)	{ set_pte(&pte, __pte(pte_val(pte) |
 static inline pte_t pte_mkdirty(pte_t pte)      { set_pte(&pte, __pte(pte_val(pte) | _PAGE_DIRTY)); return pte; }
 static inline pte_t pte_mkyoung(pte_t pte)      { set_pte(&pte, __pte(pte_val(pte) | _PAGE_ACCESSED)); return pte; }
 static inline pte_t pte_mkhuge(pte_t pte)       { set_pte(&pte, __pte(pte_val(pte) | _PAGE_SZHUGE)); return pte; }
+static inline pte_t pte_mkspecial(pte_t pte)    { return pte; }
 
 
 /*
diff --git a/include/asm-sparc/pgtable.h b/include/asm-sparc/pgtable.h
index 2cc235b74d94..d84af6d95f5c 100644
--- a/include/asm-sparc/pgtable.h
+++ b/include/asm-sparc/pgtable.h
@@ -219,6 +219,11 @@ static inline int pte_file(pte_t pte)
         return pte_val(pte) & BTFIXUP_HALF(pte_filei);
 }
 
+static inline int pte_special(pte_t pte)
+{
+        return 0;
+}
+
 /*
  */
 BTFIXUPDEF_HALF(pte_wrprotecti)
@@ -251,6 +256,8 @@ BTFIXUPDEF_CALL_CONST(pte_t, pte_mkyoung, pte_t)
 #define pte_mkdirty(pte) BTFIXUP_CALL(pte_mkdirty)(pte)
 #define pte_mkyoung(pte) BTFIXUP_CALL(pte_mkyoung)(pte)
 
+#define pte_mkspecial(pte)    (pte)
+
 #define pfn_pte(pfn, prot)              mk_pte(pfn_to_page(pfn), prot)
 
 BTFIXUPDEF_CALL(unsigned long,   pte_pfn, pte_t)
diff --git a/include/asm-sparc64/pgtable.h b/include/asm-sparc64/pgtable.h
index 549e45266b68..0e200e7acec7 100644
--- a/include/asm-sparc64/pgtable.h
+++ b/include/asm-sparc64/pgtable.h
@@ -506,6 +506,11 @@ static inline pte_t pte_mkyoung(pte_t pte)
         return __pte(pte_val(pte) | mask);
 }
 
+static inline pte_t pte_mkspecial(pte_t pte)
+{
+        return pte;
+}
+
 static inline unsigned long pte_young(pte_t pte)
 {
         unsigned long mask;
@@ -608,6 +613,11 @@ static inline unsigned long pte_present(pte_t pte)
         return val;
 }
 
+static inline int pte_special(pte_t pte)
+{
+        return 0;
+}
+
 #define pmd_set(pmdp, ptep)     \
         (pmd_val(*(pmdp)) = (__pa((unsigned long) (ptep)) >> 11UL))
 #define pud_set(pudp, pmdp)     \
diff --git a/include/asm-um/pgtable.h b/include/asm-um/pgtable.h
index 4102b443e925..02db81b7b86e 100644
--- a/include/asm-um/pgtable.h
+++ b/include/asm-um/pgtable.h
@@ -173,6 +173,11 @@ static inline int pte_newprot(pte_t pte)
         return(pte_present(pte) && (pte_get_bits(pte, _PAGE_NEWPROT)));
 }
 
+static inline int pte_special(pte_t pte)
+{
+        return 0;
+}
+
 /*
  * =================================
  * Flags setting section.
@@ -241,6 +246,11 @@ static inline pte_t pte_mknewpage(pte_t pte)
         return(pte);
 }
 
+static inline pte_t pte_mkspecial(pte_t pte)
+{
+        return(pte);
+}
+
 static inline void set_pte(pte_t *pteptr, pte_t pteval)
 {
         pte_copy(*pteptr, pteval);
diff --git a/include/asm-x86/pgtable.h b/include/asm-x86/pgtable.h
index a496d6335d3b..801b31f71452 100644
--- a/include/asm-x86/pgtable.h
+++ b/include/asm-x86/pgtable.h
@@ -195,6 +195,11 @@ static inline int pte_exec(pte_t pte)
         return !(pte_val(pte) & _PAGE_NX);
 }
 
+static inline int pte_special(pte_t pte)
+{
+        return 0;
+}
+
 static inline int pmd_large(pmd_t pte)
 {
         return (pmd_val(pte) & (_PAGE_PSE | _PAGE_PRESENT)) ==
@@ -256,6 +261,11 @@ static inline pte_t pte_clrglobal(pte_t pte)
         return __pte(pte_val(pte) & ~(pteval_t)_PAGE_GLOBAL);
 }
 
+static inline pte_t pte_mkspecial(pte_t pte)
+{
+        return pte;
+}
+
 extern pteval_t __supported_pte_mask;
 
 static inline pte_t pfn_pte(unsigned long page_nr, pgprot_t pgprot)
diff --git a/include/asm-xtensa/pgtable.h b/include/asm-xtensa/pgtable.h
index c8b024a48b4d..8014d96b21f1 100644
--- a/include/asm-xtensa/pgtable.h
+++ b/include/asm-xtensa/pgtable.h
@@ -210,6 +210,8 @@ static inline int pte_write(pte_t pte) { return pte_val(pte) & _PAGE_WRITABLE; }
 static inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; }
 static inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; }
 static inline int pte_file(pte_t pte)  { return pte_val(pte) & _PAGE_FILE; }
+static inline int pte_special(pte_t pte) { return 0; }
+
 static inline pte_t pte_wrprotect(pte_t pte)    
         { pte_val(pte) &= ~(_PAGE_WRITABLE | _PAGE_HW_WRITE); return pte; }
 static inline pte_t pte_mkclean(pte_t pte)
@@ -222,6 +224,8 @@ static inline pte_t pte_mkyoung(pte_t pte)
         { pte_val(pte) |= _PAGE_ACCESSED; return pte; }
 static inline pte_t pte_mkwrite(pte_t pte)
         { pte_val(pte) |= _PAGE_WRITABLE; return pte; }
+static inline pte_t pte_mkspecial(pte_t pte)
+        { return pte; }
 
 /*
  * Conversion functions: convert a page and protection to a page entry,
diff --git a/include/linux/mm.h b/include/linux/mm.h
index c657ea0bd6aa..ba86ddaa2bb8 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -721,7 +721,9 @@ struct zap_details {
         unsigned long truncate_count;           /* Compare vm_truncate_count */
 };
 
-struct page *vm_normal_page(struct vm_area_struct *, unsigned long, pte_t);
+struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
+                pte_t pte);
+
 unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
                 unsigned long size, struct zap_details *);
 unsigned long unmap_vmas(struct mmu_gather **tlb,
diff --git a/mm/memory.c b/mm/memory.c
index 0da414c383e7..c5e88bcd8ec3 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -371,33 +371,37 @@ static inline int is_cow_mapping(unsigned int flags)
 }
 
 /*
- * This function gets the "struct page" associated with a pte or returns
- * NULL if no "struct page" is associated with the pte.
+ * vm_normal_page -- This function gets the "struct page" associated with a pte.
  *
- * A raw VM_PFNMAP mapping (ie. one that is not COWed) may not have any "struct
- * page" backing, and even if they do, they are not refcounted. COWed pages of
- * a VM_PFNMAP do always have a struct page, and they are normally refcounted
- * (they are _normal_ pages).
+ * "Special" mappings do not wish to be associated with a "struct page" (either
+ * it doesn't exist, or it exists but they don't want to touch it). In this
+ * case, NULL is returned here. "Normal" mappings do have a struct page.
  *
- * So a raw PFNMAP mapping will have each page table entry just pointing
- * to a page frame number, and as far as the VM layer is concerned, those do
- * not have pages associated with them - even if the PFN might point to memory
- * that otherwise is perfectly fine and has a "struct page".
+ * There are 2 broad cases. Firstly, an architecture may define a pte_special()
+ * pte bit, in which case this function is trivial. Secondly, an architecture
+ * may not have a spare pte bit, which requires a more complicated scheme,
+ * described below.
+ *
+ * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
+ * special mapping (even if there are underlying and valid "struct pages").
+ * COWed pages of a VM_PFNMAP are always normal.
  *
  * The way we recognize COWed pages within VM_PFNMAP mappings is through the
  * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
- * set, and the vm_pgoff will point to the first PFN mapped: thus every
- * page that is a raw mapping will always honor the rule
+ * set, and the vm_pgoff will point to the first PFN mapped: thus every special
+ * mapping will always honor the rule
  *
  *      pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
  *
- * A call to vm_normal_page() will return NULL for such a page.
+ * And for normal mappings this is false.
+ *
+ * This restricts such mappings to be a linear translation from virtual address
+ * to pfn. To get around this restriction, we allow arbitrary mappings so long
+ * as the vma is not a COW mapping; in that case, we know that all ptes are
+ * special (because none can have been COWed).
  *
- * If the page doesn't follow the "remap_pfn_range()" rule in a VM_PFNMAP
- * then the page has been COW'ed.  A COW'ed page _does_ have a "struct page"
- * associated with it even if it is in a VM_PFNMAP range.  Calling
- * vm_normal_page() on such a page will therefore return the "struct page".
  *
+ * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
  *
  * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
  * page" backing, however the difference is that _all_ pages with a struct
@@ -407,16 +411,29 @@ static inline int is_cow_mapping(unsigned int flags)
  * advantage is that we don't have to follow the strict linearity rule of
  * PFNMAP mappings in order to support COWable mappings.
  *
- * A call to vm_normal_page() with a VM_MIXEDMAP mapping will return the
- * associated "struct page" or NULL for memory not backed by a "struct page".
- *
- *
- * All other mappings should have a valid struct page, which will be
- * returned by a call to vm_normal_page().
  */
-struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
+#ifdef __HAVE_ARCH_PTE_SPECIAL
+# define HAVE_PTE_SPECIAL 1
+#else
+# define HAVE_PTE_SPECIAL 0
+#endif
+struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
+                                pte_t pte)
 {
-        unsigned long pfn = pte_pfn(pte);
+        unsigned long pfn;
+
+        if (HAVE_PTE_SPECIAL) {
+                if (likely(!pte_special(pte))) {
+                        VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
+                        return pte_page(pte);
+                }
+                VM_BUG_ON(!(vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)));
+                return NULL;
+        }
+
+        /* !HAVE_PTE_SPECIAL case follows: */
+
+        pfn = pte_pfn(pte);
 
         if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
                 if (vma->vm_flags & VM_MIXEDMAP) {
@@ -424,7 +441,8 @@ struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, pte_
                                 return NULL;
                         goto out;
                 } else {
-                        unsigned long off = (addr-vma->vm_start) >> PAGE_SHIFT;
+                        unsigned long off;
+                        off = (addr - vma->vm_start) >> PAGE_SHIFT;
                         if (pfn == vma->vm_pgoff + off)
                                 return NULL;
                         if (!is_cow_mapping(vma->vm_flags))
@@ -432,25 +450,12 @@ struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, pte_
                 }
         }
 
-#ifdef CONFIG_DEBUG_VM
-        /*
-         * Add some anal sanity checks for now. Eventually,
-         * we should just do "return pfn_to_page(pfn)", but
-         * in the meantime we check that we get a valid pfn,
-         * and that the resulting page looks ok.
-         */
-        if (unlikely(!pfn_valid(pfn))) {
-                print_bad_pte(vma, pte, addr);
-                return NULL;
-        }
-#endif
+        VM_BUG_ON(!pfn_valid(pfn));
 
         /*
-         * NOTE! We still have PageReserved() pages in the page 
-         * tables. 
+         * NOTE! We still have PageReserved() pages in the page tables.
          *
-         * The PAGE_ZERO() pages and various VDSO mappings can
-         * cause them to exist.
+         * eg. VDSO mappings can cause them to exist.
          */
 out:
         return pfn_to_page(pfn);
@@ -1263,6 +1268,12 @@ int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
         pte_t *pte, entry;
         spinlock_t *ptl;
 
+        /*
+         * Technically, architectures with pte_special can avoid all these
+         * restrictions (same for remap_pfn_range).  However we would like
+         * consistency in testing and feature parity among all, so we should
+         * try to keep these invariants in place for everybody.
+         */
         BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
         BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
                                                 (VM_PFNMAP|VM_MIXEDMAP));
@@ -1278,7 +1289,7 @@ int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
                 goto out_unlock;
 
         /* Ok, finally just insert the thing.. */
-        entry = pfn_pte(pfn, vma->vm_page_prot);
+        entry = pte_mkspecial(pfn_pte(pfn, vma->vm_page_prot));
         set_pte_at(mm, addr, pte, entry);
         update_mmu_cache(vma, addr, entry);
 
@@ -1309,7 +1320,7 @@ static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
         arch_enter_lazy_mmu_mode();
         do {
                 BUG_ON(!pte_none(*pte));
-                set_pte_at(mm, addr, pte, pfn_pte(pfn, prot));
+                set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot)));
                 pfn++;
         } while (pte++, addr += PAGE_SIZE, addr != end);
         arch_leave_lazy_mmu_mode();