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-rw-r--r--include/asm-s390/pgtable.h50
1 files changed, 40 insertions, 10 deletions
diff --git a/include/asm-s390/pgtable.h b/include/asm-s390/pgtable.h
index 519f0a5ff18..36bb6dacf00 100644
--- a/include/asm-s390/pgtable.h
+++ b/include/asm-s390/pgtable.h
@@ -200,18 +200,45 @@ extern char empty_zero_page[PAGE_SIZE];
*/
/* Hardware bits in the page table entry */
-#define _PAGE_RO 0x200 /* HW read-only */
-#define _PAGE_INVALID 0x400 /* HW invalid */
+#define _PAGE_RO 0x200 /* HW read-only bit */
+#define _PAGE_INVALID 0x400 /* HW invalid bit */
+#define _PAGE_SWT 0x001 /* SW pte type bit t */
+#define _PAGE_SWX 0x002 /* SW pte type bit x */
-/* Mask and six different types of pages. */
-#define _PAGE_TYPE_MASK 0x601
+/* Six different types of pages. */
#define _PAGE_TYPE_EMPTY 0x400
#define _PAGE_TYPE_NONE 0x401
-#define _PAGE_TYPE_SWAP 0x600
-#define _PAGE_TYPE_FILE 0x601
+#define _PAGE_TYPE_SWAP 0x403
+#define _PAGE_TYPE_FILE 0x601 /* bit 0x002 is used for offset !! */
#define _PAGE_TYPE_RO 0x200
#define _PAGE_TYPE_RW 0x000
+/*
+ * PTE type bits are rather complicated. handle_pte_fault uses pte_present,
+ * pte_none and pte_file to find out the pte type WITHOUT holding the page
+ * table lock. ptep_clear_flush on the other hand uses ptep_clear_flush to
+ * invalidate a given pte. ipte sets the hw invalid bit and clears all tlbs
+ * for the page. The page table entry is set to _PAGE_TYPE_EMPTY afterwards.
+ * This change is done while holding the lock, but the intermediate step
+ * of a previously valid pte with the hw invalid bit set can be observed by
+ * handle_pte_fault. That makes it necessary that all valid pte types with
+ * the hw invalid bit set must be distinguishable from the four pte types
+ * empty, none, swap and file.
+ *
+ * irxt ipte irxt
+ * _PAGE_TYPE_EMPTY 1000 -> 1000
+ * _PAGE_TYPE_NONE 1001 -> 1001
+ * _PAGE_TYPE_SWAP 1011 -> 1011
+ * _PAGE_TYPE_FILE 11?1 -> 11?1
+ * _PAGE_TYPE_RO 0100 -> 1100
+ * _PAGE_TYPE_RW 0000 -> 1000
+ *
+ * pte_none is true for bits combinations 1000, 1100
+ * pte_present is true for bits combinations 0000, 0010, 0100, 0110, 1001
+ * pte_file is true for bits combinations 1101, 1111
+ * swap pte is 1011 and 0001, 0011, 0101, 0111, 1010 and 1110 are invalid.
+ */
+
#ifndef __s390x__
/* Bits in the segment table entry */
@@ -365,18 +392,21 @@ static inline int pmd_bad(pmd_t pmd)
static inline int pte_none(pte_t pte)
{
- return (pte_val(pte) & _PAGE_TYPE_MASK) == _PAGE_TYPE_EMPTY;
+ return (pte_val(pte) & _PAGE_INVALID) && !(pte_val(pte) & _PAGE_SWT);
}
static inline int pte_present(pte_t pte)
{
- return !(pte_val(pte) & _PAGE_INVALID) ||
- (pte_val(pte) & _PAGE_TYPE_MASK) == _PAGE_TYPE_NONE;
+ unsigned long mask = _PAGE_RO | _PAGE_INVALID | _PAGE_SWT | _PAGE_SWX;
+ return (pte_val(pte) & mask) == _PAGE_TYPE_NONE ||
+ (!(pte_val(pte) & _PAGE_INVALID) &&
+ !(pte_val(pte) & _PAGE_SWT));
}
static inline int pte_file(pte_t pte)
{
- return (pte_val(pte) & _PAGE_TYPE_MASK) == _PAGE_TYPE_FILE;
+ unsigned long mask = _PAGE_RO | _PAGE_INVALID | _PAGE_SWT;
+ return (pte_val(pte) & mask) == _PAGE_TYPE_FILE;
}
#define pte_same(a,b) (pte_val(a) == pte_val(b))