1 files changed, 67 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/pte-8xx.h b/arch/powerpc/include/asm/pte-8xx.h
new file mode 100644
index 000000000000..8c6e31251034
--- /dev/null
+++ b/arch/powerpc/include/asm/pte-8xx.h
@@ -0,0 +1,67 @@
+#ifndef _ASM_POWERPC_PTE_8xx_H
+#define _ASM_POWERPC_PTE_8xx_H
+#ifdef __KERNEL__
+
+/*
+ * The PowerPC MPC8xx uses a TLB with hardware assisted, software tablewalk.
+ * We also use the two level tables, but we can put the real bits in them
+ * needed for the TLB and tablewalk.  These definitions require Mx_CTR.PPM = 0,
+ * Mx_CTR.PPCS = 0, and MD_CTR.TWAM = 1.  The level 2 descriptor has
+ * additional page protection (when Mx_CTR.PPCS = 1) that allows TLB hit
+ * based upon user/super access.  The TLB does not have accessed nor write
+ * protect.  We assume that if the TLB get loaded with an entry it is
+ * accessed, and overload the changed bit for write protect.  We use
+ * two bits in the software pte that are supposed to be set to zero in
+ * the TLB entry (24 and 25) for these indicators.  Although the level 1
+ * descriptor contains the guarded and writethrough/copyback bits, we can
+ * set these at the page level since they get copied from the Mx_TWC
+ * register when the TLB entry is loaded.  We will use bit 27 for guard, since
+ * that is where it exists in the MD_TWC, and bit 26 for writethrough.
+ * These will get masked from the level 2 descriptor at TLB load time, and
+ * copied to the MD_TWC before it gets loaded.
+ * Large page sizes added.  We currently support two sizes, 4K and 8M.
+ * This also allows a TLB hander optimization because we can directly
+ * load the PMD into MD_TWC.  The 8M pages are only used for kernel
+ * mapping of well known areas.  The PMD (PGD) entries contain control
+ * flags in addition to the address, so care must be taken that the
+ * software no longer assumes these are only pointers.
+ */
+
+/* Definitions for 8xx embedded chips. */
+#define _PAGE_PRESENT   0x0001  /* Page is valid */
+#define _PAGE_FILE      0x0002  /* when !present: nonlinear file mapping */
+#define _PAGE_NO_CACHE  0x0002  /* I: cache inhibit */
+#define _PAGE_SHARED    0x0004  /* No ASID (context) compare */
+
+/* These five software bits must be masked out when the entry is loaded
+ * into the TLB.
+ */
+#define _PAGE_EXEC      0x0008  /* software: i-cache coherency required */
+#define _PAGE_GUARDED   0x0010  /* software: guarded access */
+#define _PAGE_DIRTY     0x0020  /* software: page changed */
+#define _PAGE_RW        0x0040  /* software: user write access allowed */
+#define _PAGE_ACCESSED  0x0080  /* software: page referenced */
+
+/* Setting any bits in the nibble with the follow two controls will
+ * require a TLB exception handler change.  It is assumed unused bits
+ * are always zero.
+ */
+#define _PAGE_HWWRITE   0x0100  /* h/w write enable: never set in Linux PTE */
+#define _PAGE_USER      0x0800  /* One of the PP bits, the other is USER&~RW */
+
+#define _PMD_PRESENT    0x0001
+#define _PMD_BAD        0x0ff0
+#define _PMD_PAGE_MASK  0x000c
+#define _PMD_PAGE_8M    0x000c
+
+#define _PTE_NONE_MASK _PAGE_ACCESSED
+
+/* Until my rework is finished, 8xx still needs atomic PTE updates */
+#define PTE_ATOMIC_UPDATES      1
+
+/* We need to add _PAGE_SHARED to kernel pages */
+#define _PAGE_KERNEL_RO (_PAGE_SHARED)
+#define _PAGE_KERNEL_RW (_PAGE_DIRTY | _PAGE_RW | _PAGE_HWWRITE)
+
+#endif /* __KERNEL__ */
+#endif /*  _ASM_POWERPC_PTE_8xx_H */