sh: Provide _PAGE_SPECIAL for 32-bit.
Allocate one of the unused PTE bits for _PAGE_SPECIAL directly. This is
prep work for fast gup and the zero page revival.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/include/asm/pgtable_32.h b/arch/sh/include/asm/pgtable_32.h
index 72ea209..0db19db 100644
--- a/arch/sh/include/asm/pgtable_32.h
+++ b/arch/sh/include/asm/pgtable_32.h
@@ -20,7 +20,7 @@
* - Bit 9 is reserved by everyone and used by _PAGE_PROTNONE.
*
* - Bits 10 and 11 are low bits of the PPN that are reserved on >= 4K pages.
- * Bit 10 is used for _PAGE_ACCESSED, bit 11 remains unused.
+ * Bit 10 is used for _PAGE_ACCESSED, and bit 11 is used for _PAGE_SPECIAL.
*
* - On 29 bit platforms, bits 31 to 29 are used for the space attributes
* and timing control which (together with bit 0) are moved into the
@@ -52,6 +52,7 @@
#define _PAGE_PROTNONE 0x200 /* software: if not present */
#define _PAGE_ACCESSED 0x400 /* software: page referenced */
#define _PAGE_FILE _PAGE_WT /* software: pagecache or swap? */
+#define _PAGE_SPECIAL 0x800 /* software: special page */
#define _PAGE_SZ_MASK (_PAGE_SZ0 | _PAGE_SZ1)
#define _PAGE_PR_MASK (_PAGE_RW | _PAGE_USER)
@@ -148,8 +149,12 @@
# define _PAGE_SZHUGE (_PAGE_FLAGS_HARD)
#endif
+/*
+ * Mask of bits that are to be preserved accross pgprot changes.
+ */
#define _PAGE_CHG_MASK \
- (PTE_MASK | _PAGE_ACCESSED | _PAGE_CACHABLE | _PAGE_DIRTY)
+ (PTE_MASK | _PAGE_ACCESSED | _PAGE_CACHABLE | \
+ _PAGE_DIRTY | _PAGE_SPECIAL)
#ifndef __ASSEMBLY__
@@ -328,7 +333,7 @@
#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)
+#define pte_special(pte) ((pte).pte_low & _PAGE_SPECIAL)
#ifdef CONFIG_X2TLB
#define pte_write(pte) ((pte).pte_high & _PAGE_EXT_USER_WRITE)
@@ -358,8 +363,9 @@
PTE_BIT_FUNC(low, mkdirty, |= _PAGE_DIRTY);
PTE_BIT_FUNC(low, mkold, &= ~_PAGE_ACCESSED);
PTE_BIT_FUNC(low, mkyoung, |= _PAGE_ACCESSED);
+PTE_BIT_FUNC(low, mkspecial, |= _PAGE_SPECIAL);
-static inline pte_t pte_mkspecial(pte_t pte) { return pte; }
+#define __HAVE_ARCH_PTE_SPECIAL
/*
* Macro and implementation to make a page protection as uncachable.