Functionality moved from directory above to accomodate building

shared source code.

c/src/lib/libcpu/powerpc/shared/include/pgtable.h

@@ -0,0 +1,146 @@
+/*
+ * pgtable.h
+ *
+ *	PowerPC memory management structures
+ *
+ * It is a stripped down version of linux ppc file...
+ *
+ * Copyright (C) 1999  Eric Valette (valette@crf.canon.fr)
+ *                     Canon Centre Recherche France.
+ *
+ *  The license and distribution terms for this file may be
+ *  found in found in the file LICENSE in this distribution or at
+ *  http://www.OARcorp.com/rtems/license.html.
+ *
+ *  $Id$
+ */
+
+#ifndef _PPC_PGTABLE_H
+#define _PPC_PGTABLE_H
+
+/*
+ * The PowerPC MMU uses a hash table containing PTEs, together with
+ * a set of 16 segment registers (on 32-bit implementations), to define
+ * the virtual to physical address mapping.
+ *
+ * We use the hash table as an extended TLB, i.e. a cache of currently
+ * active mappings.  We maintain a two-level page table tree, much like
+ * that used by the i386, for the sake of the Linux memory management code.
+ * Low-level assembler code in head.S (procedure hash_page) is responsible
+ * for extracting ptes from the tree and putting them into the hash table
+ * when necessary, and updating the accessed and modified bits in the
+ * page table tree.
+ *
+ * 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.
+ */
+
+/* PMD_SHIFT determines the size of the area mapped by the second-level page tables */
+#define PMD_SHIFT	22
+#define PMD_SIZE	(1UL << PMD_SHIFT)
+#define PMD_MASK	(~(PMD_SIZE-1))
+
+/* PGDIR_SHIFT determines what a third-level page table entry can map */
+#define PGDIR_SHIFT	22
+#define PGDIR_SIZE	(1UL << PGDIR_SHIFT)
+#define PGDIR_MASK	(~(PGDIR_SIZE-1))
+
+/*
+ * entries per page directory level: our page-table tree is two-level, so
+ * we don't really have any PMD directory.
+ */
+#define PTRS_PER_PTE	1024
+#define PTRS_PER_PMD	1
+#define PTRS_PER_PGD	1024
+#define USER_PTRS_PER_PGD	(TASK_SIZE / PGDIR_SIZE)
+
+/* Just any arbitrary offset to the start of the vmalloc VM area: the
+ * current 64MB value just means that there will be a 64MB "hole" after the
+ * physical memory until the kernel virtual memory starts.  That means that
+ * any out-of-bounds memory accesses will hopefully be caught.
+ * The vmalloc() routines leaves a hole of 4kB between each vmalloced
+ * area for the same reason. ;)
+ *
+ * We no longer map larger than phys RAM with the BATs so we don't have
+ * to worry about the VMALLOC_OFFSET causing problems.  We do have to worry
+ * about clashes between our early calls to ioremap() that start growing down
+ * from ioremap_base being run into the VM area allocations (growing upwards
+ * from VMALLOC_START).  For this reason we have ioremap_bot to check when
+ * we actually run into our mappings setup in the early boot with the VM
+ * system.  This really does become a problem for machines with good amounts
+ * of RAM.  -- Cort
+ */
+#define VMALLOC_OFFSET (0x4000000) /* 64M */
+#define VMALLOC_START ((((long)high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1)))
+#define VMALLOC_VMADDR(x) ((unsigned long)(x))
+#define VMALLOC_END	ioremap_bot
+
+/*
+ * Bits in a linux-style PTE.  These match the bits in the
+ * (hardware-defined) PowerPC PTE as closely as possible.
+ */
+#define _PAGE_PRESENT	0x001	/* software: pte contains a translation */
+#define _PAGE_USER	0x002	/* matches one of the PP bits */
+#define _PAGE_RW	0x004	/* software: user write access allowed */
+#define _PAGE_GUARDED	0x008
+#define _PAGE_COHERENT	0x010	/* M: enforce memory coherence (SMP systems) */
+#define _PAGE_NO_CACHE	0x020	/* I: cache inhibit */
+#define _PAGE_WRITETHRU	0x040	/* W: cache write-through */
+#define _PAGE_DIRTY	0x080	/* C: page changed */
+#define _PAGE_ACCESSED	0x100	/* R: page referenced */
+#define _PAGE_HWWRITE	0x200	/* software: _PAGE_RW & _PAGE_DIRTY */
+#define _PAGE_SHARED	0
+
+#define _PAGE_CHG_MASK	(PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
+
+#define _PAGE_BASE	_PAGE_PRESENT | _PAGE_ACCESSED
+#define _PAGE_WRENABLE	_PAGE_RW | _PAGE_DIRTY | _PAGE_HWWRITE
+
+#define PAGE_NONE	__pgprot(_PAGE_PRESENT | _PAGE_ACCESSED)
+
+#define PAGE_SHARED	__pgprot(_PAGE_BASE | _PAGE_RW | _PAGE_USER | \
+				 _PAGE_SHARED)
+#define PAGE_COPY	__pgprot(_PAGE_BASE | _PAGE_USER)
+#define PAGE_READONLY	__pgprot(_PAGE_BASE | _PAGE_USER)
+#define PAGE_KERNEL	__pgprot(_PAGE_BASE | _PAGE_WRENABLE | _PAGE_SHARED)
+#define PAGE_KERNEL_CI	__pgprot(_PAGE_BASE | _PAGE_WRENABLE | _PAGE_SHARED | \
+				 _PAGE_NO_CACHE )
+
+/*
+ * The PowerPC can only do execute protection on a segment (256MB) basis,
+ * not on a page basis.  So we consider execute permission the same as read.
+ * Also, write permissions imply read permissions.
+ * This is the closest we can get..
+ */
+#define __P000	PAGE_NONE
+#define __P001	PAGE_READONLY
+#define __P010	PAGE_COPY
+#define __P011	PAGE_COPY
+#define __P100	PAGE_READONLY
+#define __P101	PAGE_READONLY
+#define __P110	PAGE_COPY
+#define __P111	PAGE_COPY
+
+#define __S000	PAGE_NONE
+#define __S001	PAGE_READONLY
+#define __S010	PAGE_SHARED
+#define __S011	PAGE_SHARED
+#define __S100	PAGE_READONLY
+#define __S101	PAGE_READONLY
+#define __S110	PAGE_SHARED
+#define __S111	PAGE_SHARED
+#endif /* _PPC_PGTABLE_H */