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authorIngo Molnar <mingo@elte.hu>2009-09-07 08:19:51 +0200
committerIngo Molnar <mingo@elte.hu>2009-09-07 08:19:51 +0200
commita1922ed661ab2c1637d0b10cde933bd9cd33d965 (patch)
tree0f1777542b385ebefd30b3586d830fd8ed6fda5b /arch/arm/include/asm/pgtable.h
parent75e33751ca8bbb72dd6f1a74d2810ddc8cbe4bdf (diff)
parentd28daf923ac5e4a0d7cecebae56f3e339189366b (diff)
downloadlinux-2.6.38-lt-ux500-a1922ed661ab2c1637d0b10cde933bd9cd33d965.tar.gz
Merge branch 'tracing/core' into tracing/hw-breakpoints
Conflicts: arch/Kconfig kernel/trace/trace.h Merge reason: resolve the conflicts, plus adopt to the new ring-buffer APIs. Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/arm/include/asm/pgtable.h')
-rw-r--r--arch/arm/include/asm/pgtable.h53
1 files changed, 39 insertions, 14 deletions
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index 1cd2d6416bd..c433c6c7311 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -285,15 +285,6 @@ extern struct page *empty_zero_page;
#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.
- */
-#define pte_file(pte) (pte_val(pte) & L_PTE_FILE)
-#define pte_to_pgoff(x) (pte_val(x) >> 2)
-#define pgoff_to_pte(x) __pte(((x) << 2) | L_PTE_FILE)
-
-#define PTE_FILE_MAX_BITS 30
-
#define PTE_BIT_FUNC(fn,op) \
static inline pte_t pte_##fn(pte_t pte) { pte_val(pte) op; return pte; }
@@ -384,16 +375,50 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
-/* Encode and decode a swap entry.
+/*
+ * Encode and decode a swap entry. Swap entries are stored in the Linux
+ * page tables as follows:
*
- * We support up to 32GB of swap on 4k machines
+ * 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
+ *
+ * This gives us up to 127 swap files and 32GB per swap file. Note that
+ * the offset field is always non-zero.
*/
-#define __swp_type(x) (((x).val >> 2) & 0x7f)
-#define __swp_offset(x) ((x).val >> 9)
-#define __swp_entry(type,offset) ((swp_entry_t) { ((type) << 2) | ((offset) << 9) })
+#define __SWP_TYPE_SHIFT 2
+#define __SWP_TYPE_BITS 7
+#define __SWP_TYPE_MASK ((1 << __SWP_TYPE_BITS) - 1)
+#define __SWP_OFFSET_SHIFT (__SWP_TYPE_BITS + __SWP_TYPE_SHIFT)
+
+#define __swp_type(x) (((x).val >> __SWP_TYPE_SHIFT) & __SWP_TYPE_MASK)
+#define __swp_offset(x) ((x).val >> __SWP_OFFSET_SHIFT)
+#define __swp_entry(type,offset) ((swp_entry_t) { ((type) << __SWP_TYPE_SHIFT) | ((offset) << __SWP_OFFSET_SHIFT) })
+
#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
#define __swp_entry_to_pte(swp) ((pte_t) { (swp).val })
+/*
+ * It is an error for the kernel to have more swap files than we can
+ * encode in the PTEs. This ensures that we know when MAX_SWAPFILES
+ * is increased beyond what we presently support.
+ */
+#define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > __SWP_TYPE_BITS)
+
+/*
+ * Encode and decode a file entry. File entries are stored in the Linux
+ * page tables as follows:
+ *
+ * 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 -------------------------> 1 0
+ */
+#define pte_file(pte) (pte_val(pte) & L_PTE_FILE)
+#define pte_to_pgoff(x) (pte_val(x) >> 2)
+#define pgoff_to_pte(x) __pte(((x) << 2) | L_PTE_FILE)
+
+#define PTE_FILE_MAX_BITS 30
+
/* Needs to be defined here and not in linux/mm.h, as it is arch dependent */
/* FIXME: this is not correct */
#define kern_addr_valid(addr) (1)