1 files changed, 97 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/pte-44x.h b/arch/powerpc/include/asm/pte-44x.h
new file mode 100644
index 000000000..36f75fab2
--- /dev/null
+++ b/arch/powerpc/include/asm/pte-44x.h
@@ -0,0 +1,97 @@
+#ifndef _ASM_POWERPC_PTE_44x_H
+#define _ASM_POWERPC_PTE_44x_H
+#ifdef __KERNEL__
+
+/*
+ * Definitions for PPC440
+ *
+ * Because of the 3 word TLB entries to support 36-bit addressing,
+ * the attribute are difficult to map in such a fashion that they
+ * are easily loaded during exception processing.  I decided to
+ * organize the entry so the ERPN is the only portion in the
+ * upper word of the PTE and the attribute bits below are packed
+ * in as sensibly as they can be in the area below a 4KB page size
+ * oriented RPN.  This at least makes it easy to load the RPN and
+ * ERPN fields in the TLB. -Matt
+ *
+ * This isn't entirely true anymore, at least some bits are now
+ * easier to move into the TLB from the PTE. -BenH.
+ *
+ * Note that these bits preclude future use of a page size
+ * less than 4KB.
+ *
+ *
+ * PPC 440 core has following TLB attribute fields;
+ *
+ *   TLB1:
+ *   0  1  2  3  4  ... 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
+ *   RPN.................................  -  -  -  -  -  - ERPN.......
+ *
+ *   TLB2:
+ *   0  1  2  3  4  ... 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
+ *   -  -  -  -  -    - U0 U1 U2 U3 W  I  M  G  E   - UX UW UR SX SW SR
+ *
+ * Newer 440 cores (440x6 as used on AMCC 460EX/460GT) have additional
+ * TLB2 storage attibute fields. Those are:
+ *
+ *   TLB2:
+ *   0...10    11   12   13   14   15   16...31
+ *   no change WL1  IL1I IL1D IL2I IL2D no change
+ *
+ * There are some constrains and options, to decide mapping software bits
+ * into TLB entry.
+ *
+ *   - PRESENT *must* be in the bottom three bits because swap cache
+ *     entries use the top 29 bits for TLB2.
+ *
+ *   - CACHE COHERENT bit (M) has no effect on original PPC440 cores,
+ *     because it doesn't support SMP. However, some later 460 variants
+ *     have -some- form of SMP support and so I keep the bit there for
+ *     future use
+ *
+ * With the PPC 44x Linux implementation, the 0-11th LSBs of the PTE are used
+ * for memory protection related functions (see PTE structure in
+ * include/asm-ppc/mmu.h).  The _PAGE_XXX definitions in this file map to the
+ * above bits.  Note that the bit values are CPU specific, not architecture
+ * specific.
+ *
+ * The kernel PTE entry holds an arch-dependent swp_entry structure under
+ * certain situations. In other words, in such situations some portion of
+ * the PTE bits are used as a swp_entry. In the PPC implementation, the
+ * 3-24th LSB are shared with swp_entry, however the 0-2nd three LSB still
+ * hold protection values. That means the three protection bits are
+ * reserved for both PTE and SWAP entry at the most significant three
+ * LSBs.
+ *
+ * There are three protection bits available for SWAP entry:
+ *	_PAGE_PRESENT
+ *	_PAGE_HASHPTE (if HW has)
+ *
+ * So those three bits have to be inside of 0-2nd LSB of PTE.
+ *
+ */
+
+#define _PAGE_PRESENT	0x00000001		/* S: PTE valid */
+#define _PAGE_RW	0x00000002		/* S: Write permission */
+#define _PAGE_EXEC	0x00000004		/* H: Execute permission */
+#define _PAGE_ACCESSED	0x00000008		/* S: Page referenced */
+#define _PAGE_DIRTY	0x00000010		/* S: Page dirty */
+#define _PAGE_SPECIAL	0x00000020		/* S: Special page */
+#define _PAGE_USER	0x00000040		/* S: User page */
+#define _PAGE_ENDIAN	0x00000080		/* H: E bit */
+#define _PAGE_GUARDED	0x00000100		/* H: G bit */
+#define _PAGE_COHERENT	0x00000200		/* H: M bit */
+#define _PAGE_NO_CACHE	0x00000400		/* H: I bit */
+#define _PAGE_WRITETHRU	0x00000800		/* H: W bit */
+
+/* TODO: Add large page lowmem mapping support */
+#define _PMD_PRESENT	0
+#define _PMD_PRESENT_MASK (PAGE_MASK)
+#define _PMD_BAD	(~PAGE_MASK)
+
+/* ERPN in a PTE never gets cleared, ignore it */
+#define _PTE_NONE_MASK	0xffffffff00000000ULL
+
+
+#endif /* __KERNEL__ */
+#endif /*  _ASM_POWERPC_PTE_44x_H */