summaryrefslogtreecommitdiff
path: root/arch/mips/include/asm/pgtable-32.h
diff options
context:
space:
mode:
Diffstat (limited to 'arch/mips/include/asm/pgtable-32.h')
-rw-r--r--arch/mips/include/asm/pgtable-32.h88
1 files changed, 76 insertions, 12 deletions
diff --git a/arch/mips/include/asm/pgtable-32.h b/arch/mips/include/asm/pgtable-32.h
index b40a0e69fccc..ba0016709a1a 100644
--- a/arch/mips/include/asm/pgtable-32.h
+++ b/arch/mips/include/asm/pgtable-32.h
@@ -191,49 +191,113 @@ static inline pte_t pfn_pte(unsigned long pfn, pgprot_t prot)
#define pte_page(x) pfn_to_page(pte_pfn(x))
+/*
+ * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that
+ * are !pte_none() && !pte_present().
+ */
#if defined(CONFIG_CPU_R3K_TLB)
-/* Swap entries must have VALID bit cleared. */
+/*
+ * Format of swap PTEs:
+ *
+ * 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
+ * 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
+ * <----------- offset ------------> < type -> V G E 0 0 0 0 0 0 P
+ *
+ * E is the exclusive marker that is not stored in swap entries.
+ * _PAGE_PRESENT (P), _PAGE_VALID (V) and_PAGE_GLOBAL (G) have to remain
+ * unused.
+ */
#define __swp_type(x) (((x).val >> 10) & 0x1f)
#define __swp_offset(x) ((x).val >> 15)
-#define __swp_entry(type,offset) ((swp_entry_t) { ((type) << 10) | ((offset) << 15) })
+#define __swp_entry(type, offset) ((swp_entry_t) { (((type) & 0x1f) << 10) | ((offset) << 15) })
#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
+/* We borrow bit 7 to store the exclusive marker in swap PTEs. */
+#define _PAGE_SWP_EXCLUSIVE (1 << 7)
+
#else
#if defined(CONFIG_XPA)
-/* Swap entries must have VALID and GLOBAL bits cleared. */
+/*
+ * Format of swap PTEs:
+ *
+ * 6 6 6 6 5 5 5 5 5 5 5 5 5 5 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3 3 3 3
+ * 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2
+ * 0 0 0 0 0 0 E P <------------------ zeroes ------------------->
+ *
+ * 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
+ * 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
+ * <----------------- offset ------------------> < type -> V G 0 0
+ *
+ * E is the exclusive marker that is not stored in swap entries.
+ * _PAGE_PRESENT (P), _PAGE_VALID (V) and_PAGE_GLOBAL (G) have to remain
+ * unused.
+ */
#define __swp_type(x) (((x).val >> 4) & 0x1f)
#define __swp_offset(x) ((x).val >> 9)
-#define __swp_entry(type,offset) ((swp_entry_t) { ((type) << 4) | ((offset) << 9) })
+#define __swp_entry(type, offset) ((swp_entry_t) { (((type) & 0x1f) << 4) | ((offset) << 9) })
#define __pte_to_swp_entry(pte) ((swp_entry_t) { (pte).pte_high })
#define __swp_entry_to_pte(x) ((pte_t) { 0, (x).val })
+/*
+ * We borrow bit 57 (bit 25 in the low PTE) to store the exclusive marker in
+ * swap PTEs.
+ */
+#define _PAGE_SWP_EXCLUSIVE (1 << 25)
+
#elif defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
-/* Swap entries must have VALID and GLOBAL bits cleared. */
+/*
+ * Format of swap PTEs:
+ *
+ * 6 6 6 6 5 5 5 5 5 5 5 5 5 5 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3 3 3 3
+ * 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2
+ * <------------------ zeroes -------------------> E P 0 0 0 0 0 0
+ *
+ * 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
+ * 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
+ * <------------------- offset --------------------> < type -> V G
+ *
+ * E is the exclusive marker that is not stored in swap entries.
+ * _PAGE_PRESENT (P), _PAGE_VALID (V) and_PAGE_GLOBAL (G) have to remain
+ * unused.
+ */
#define __swp_type(x) (((x).val >> 2) & 0x1f)
#define __swp_offset(x) ((x).val >> 7)
-#define __swp_entry(type, offset) ((swp_entry_t) { ((type) << 2) | ((offset) << 7) })
+#define __swp_entry(type, offset) ((swp_entry_t) { (((type) & 0x1f) << 2) | ((offset) << 7) })
#define __pte_to_swp_entry(pte) ((swp_entry_t) { (pte).pte_high })
#define __swp_entry_to_pte(x) ((pte_t) { 0, (x).val })
+/*
+ * We borrow bit 39 (bit 7 in the low PTE) to store the exclusive marker in swap
+ * PTEs.
+ */
+#define _PAGE_SWP_EXCLUSIVE (1 << 7)
+
#else
/*
- * Constraints:
- * _PAGE_PRESENT at bit 0
- * _PAGE_MODIFIED at bit 4
- * _PAGE_GLOBAL at bit 6
- * _PAGE_VALID at bit 7
+ * Format of swap PTEs:
+ *
+ * 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
+ * 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
+ * <------------- offset --------------> < type -> 0 0 0 0 0 0 E P
+ *
+ * E is the exclusive marker that is not stored in swap entries.
+ * _PAGE_PRESENT (P), _PAGE_VALID (V) and_PAGE_GLOBAL (G) have to remain
+ * unused. The location of V and G varies.
*/
#define __swp_type(x) (((x).val >> 8) & 0x1f)
#define __swp_offset(x) ((x).val >> 13)
-#define __swp_entry(type,offset) ((swp_entry_t) { ((type) << 8) | ((offset) << 13) })
+#define __swp_entry(type, offset) ((swp_entry_t) { ((type) << 8) | ((offset) << 13) })
#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
+/* We borrow bit 1 to store the exclusive marker in swap PTEs. */
+#define _PAGE_SWP_EXCLUSIVE (1 << 1)
+
#endif /* defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32) */
#endif /* defined(CONFIG_CPU_R3K_TLB) */