1 files changed, 299 insertions, 0 deletions

diff --git a/arch/cris/include/asm/pgtable.h b/arch/cris/include/asm/pgtable.h
new file mode 100644
index 000000000000..50aa974aa834
--- /dev/null
+++ b/arch/cris/include/asm/pgtable.h
@@ -0,0 +1,299 @@
+/*
+ * CRIS pgtable.h - macros and functions to manipulate page tables.
+ */
+
+#ifndef _CRIS_PGTABLE_H
+#define _CRIS_PGTABLE_H
+
+#include <asm/page.h>
+#include <asm-generic/pgtable-nopmd.h>
+
+#ifndef __ASSEMBLY__
+#include <linux/sched.h>
+#include <asm/mmu.h>
+#endif
+#include <arch/pgtable.h>
+
+/*
+ * The Linux memory management assumes a three-level page table setup. On
+ * CRIS, we use that, but "fold" the mid level into the top-level page
+ * table. Since the MMU TLB is software loaded through an interrupt, it
+ * supports any page table structure, so we could have used a three-level
+ * setup, but for the amounts of memory we normally use, a two-level is
+ * probably more efficient.
+ *
+ * This file contains the functions and defines necessary to modify and use
+ * the CRIS page table tree.
+ */
+#ifndef __ASSEMBLY__
+extern void paging_init(void);
+#endif
+
+/* Certain architectures need to do special things when pte's
+ * within a page table are directly modified.  Thus, the following
+ * hook is made available.
+ */
+#define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
+#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
+
+/*
+ * (pmds are folded into pgds so this doesn't get actually called,
+ * but the define is needed for a generic inline function.)
+ */
+#define set_pmd(pmdptr, pmdval) (*(pmdptr) = pmdval)
+#define set_pgu(pudptr, pudval) (*(pudptr) = pudval)
+
+/* PGDIR_SHIFT determines the size of the area a second-level page table can
+ * map. It is equal to the page size times the number of PTE's that fit in
+ * a PMD page. A PTE is 4-bytes in CRIS. Hence the following number.
+ */
+
+#define PGDIR_SHIFT     (PAGE_SHIFT + (PAGE_SHIFT-2))
+#define PGDIR_SIZE      (1UL << PGDIR_SHIFT)
+#define PGDIR_MASK      (~(PGDIR_SIZE-1))
+
+/*
+ * entries per page directory level: we use a two-level, so
+ * we don't really have any PMD directory physically.
+ * pointers are 4 bytes so we can use the page size and 
+ * divide it by 4 (shift by 2).
+ */
+#define PTRS_PER_PTE    (1UL << (PAGE_SHIFT-2))
+#define PTRS_PER_PGD    (1UL << (PAGE_SHIFT-2))
+
+/* calculate how many PGD entries a user-level program can use
+ * the first mappable virtual address is 0
+ * (TASK_SIZE is the maximum virtual address space)
+ */
+
+#define USER_PTRS_PER_PGD       (TASK_SIZE/PGDIR_SIZE)
+#define FIRST_USER_ADDRESS      0
+
+/* zero page used for uninitialized stuff */
+#ifndef __ASSEMBLY__
+extern unsigned long empty_zero_page;
+#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
+#endif
+
+/* number of bits that fit into a memory pointer */
+#define BITS_PER_PTR                    (8*sizeof(unsigned long))
+
+/* to align the pointer to a pointer address */
+#define PTR_MASK                        (~(sizeof(void*)-1))
+
+/* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
+/* 64-bit machines, beware!  SRB. */
+#define SIZEOF_PTR_LOG2                 2
+
+/* to find an entry in a page-table */
+#define PAGE_PTR(address) \
+((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
+
+/* to set the page-dir */
+#define SET_PAGE_DIR(tsk,pgdir)
+
+#define pte_none(x)     (!pte_val(x))
+#define pte_present(x)  (pte_val(x) & _PAGE_PRESENT)
+#define pte_clear(mm,addr,xp)   do { pte_val(*(xp)) = 0; } while (0)
+
+#define pmd_none(x)     (!pmd_val(x))
+/* by removing the _PAGE_KERNEL bit from the comparision, the same pmd_bad
+ * works for both _PAGE_TABLE and _KERNPG_TABLE pmd entries.
+ */
+#define pmd_bad(x)      ((pmd_val(x) & (~PAGE_MASK & ~_PAGE_KERNEL)) != _PAGE_TABLE)
+#define pmd_present(x)  (pmd_val(x) & _PAGE_PRESENT)
+#define pmd_clear(xp)   do { pmd_val(*(xp)) = 0; } while (0)
+
+#ifndef __ASSEMBLY__
+
+/*
+ * The following only work if pte_present() is true.
+ * Undefined behaviour if not..
+ */
+
+static inline int pte_write(pte_t pte)          { return pte_val(pte) & _PAGE_WRITE; }
+static inline int pte_dirty(pte_t pte)          { return pte_val(pte) & _PAGE_MODIFIED; }
+static inline int pte_young(pte_t pte)          { return pte_val(pte) & _PAGE_ACCESSED; }
+static inline int pte_file(pte_t pte)           { return pte_val(pte) & _PAGE_FILE; }
+static inline int pte_special(pte_t pte)        { return 0; }
+
+static inline pte_t pte_wrprotect(pte_t pte)
+{
+        pte_val(pte) &= ~(_PAGE_WRITE | _PAGE_SILENT_WRITE);
+        return pte;
+}
+
+static inline pte_t pte_mkclean(pte_t pte)
+{
+        pte_val(pte) &= ~(_PAGE_MODIFIED | _PAGE_SILENT_WRITE); 
+        return pte; 
+}
+
+static inline pte_t pte_mkold(pte_t pte)
+{
+        pte_val(pte) &= ~(_PAGE_ACCESSED | _PAGE_SILENT_READ);
+        return pte;
+}
+
+static inline pte_t pte_mkwrite(pte_t pte)
+{
+        pte_val(pte) |= _PAGE_WRITE;
+        if (pte_val(pte) & _PAGE_MODIFIED)
+                pte_val(pte) |= _PAGE_SILENT_WRITE;
+        return pte;
+}
+
+static inline pte_t pte_mkdirty(pte_t pte)
+{
+        pte_val(pte) |= _PAGE_MODIFIED;
+        if (pte_val(pte) & _PAGE_WRITE)
+                pte_val(pte) |= _PAGE_SILENT_WRITE;
+        return pte;
+}
+
+static inline pte_t pte_mkyoung(pte_t pte)
+{
+        pte_val(pte) |= _PAGE_ACCESSED;
+        if (pte_val(pte) & _PAGE_READ)
+        {
+                pte_val(pte) |= _PAGE_SILENT_READ;
+                if ((pte_val(pte) & (_PAGE_WRITE | _PAGE_MODIFIED)) ==
+                    (_PAGE_WRITE | _PAGE_MODIFIED))
+                        pte_val(pte) |= _PAGE_SILENT_WRITE;
+        }
+        return pte;
+}
+static inline pte_t pte_mkspecial(pte_t pte)    { return pte; }
+
+/*
+ * Conversion functions: convert a page and protection to a page entry,
+ * and a page entry and page directory to the page they refer to.
+ */
+
+/* What actually goes as arguments to the various functions is less than
+ * obvious, but a rule of thumb is that struct page's goes as struct page *,
+ * really physical DRAM addresses are unsigned long's, and DRAM "virtual"
+ * addresses (the 0xc0xxxxxx's) goes as void *'s.
+ */
+
+static inline pte_t __mk_pte(void * page, pgprot_t pgprot)
+{
+        pte_t pte;
+        /* the PTE needs a physical address */
+        pte_val(pte) = __pa(page) | pgprot_val(pgprot);
+        return pte;
+}
+
+#define mk_pte(page, pgprot) __mk_pte(page_address(page), (pgprot))
+
+#define mk_pte_phys(physpage, pgprot) \
+({                                                                      \
+        pte_t __pte;                                                    \
+                                                                        \
+        pte_val(__pte) = (physpage) + pgprot_val(pgprot);               \
+        __pte;                                                          \
+})
+
+static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
+{ pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }
+
+
+/* pte_val refers to a page in the 0x4xxxxxxx physical DRAM interval
+ * __pte_page(pte_val) refers to the "virtual" DRAM interval
+ * pte_pagenr refers to the page-number counted starting from the virtual DRAM start
+ */
+
+static inline unsigned long __pte_page(pte_t pte)
+{
+        /* the PTE contains a physical address */
+        return (unsigned long)__va(pte_val(pte) & PAGE_MASK);
+}
+
+#define pte_pagenr(pte)         ((__pte_page(pte) - PAGE_OFFSET) >> PAGE_SHIFT)
+
+/* permanent address of a page */
+
+#define __page_address(page)    (PAGE_OFFSET + (((page) - mem_map) << PAGE_SHIFT))
+#define pte_page(pte)           (mem_map+pte_pagenr(pte))
+
+/* only the pte's themselves need to point to physical DRAM (see above)
+ * the pagetable links are purely handled within the kernel SW and thus
+ * don't need the __pa and __va transformations.
+ */
+
+static inline void pmd_set(pmd_t * pmdp, pte_t * ptep)
+{ pmd_val(*pmdp) = _PAGE_TABLE | (unsigned long) ptep; }
+
+#define pmd_page(pmd)           (pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT))
+#define pmd_page_vaddr(pmd)     ((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
+
+/* to find an entry in a page-table-directory. */
+#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
+
+/* to find an entry in a page-table-directory */
+static inline pgd_t * pgd_offset(const struct mm_struct *mm, unsigned long address)
+{
+        return mm->pgd + pgd_index(address);
+}
+
+/* to find an entry in a kernel page-table-directory */
+#define pgd_offset_k(address) pgd_offset(&init_mm, address)
+
+/* Find an entry in the third-level page table.. */
+#define __pte_offset(address) \
+        (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
+#define pte_offset_kernel(dir, address) \
+        ((pte_t *) pmd_page_vaddr(*(dir)) +  __pte_offset(address))
+#define pte_offset_map(dir, address) \
+        ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
+#define pte_offset_map_nested(dir, address) pte_offset_map(dir, address)
+
+#define pte_unmap(pte) do { } while (0)
+#define pte_unmap_nested(pte) do { } while (0)
+#define pte_pfn(x)              ((unsigned long)(__va((x).pte)) >> PAGE_SHIFT)
+#define pfn_pte(pfn, prot)      __pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
+
+#define pte_ERROR(e) \
+        printk("%s:%d: bad pte %p(%08lx).\n", __FILE__, __LINE__, &(e), pte_val(e))
+#define pgd_ERROR(e) \
+        printk("%s:%d: bad pgd %p(%08lx).\n", __FILE__, __LINE__, &(e), pgd_val(e))
+
+
+extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; /* defined in head.S */
+
+/*
+ * CRIS doesn't have any external MMU info: the kernel page
+ * tables contain all the necessary information.
+ * 
+ * Actually I am not sure on what this could be used for.
+ */
+static inline void update_mmu_cache(struct vm_area_struct * vma,
+        unsigned long address, pte_t pte)
+{
+}
+
+/* Encode and de-code a swap entry (must be !pte_none(e) && !pte_present(e)) */
+/* Since the PAGE_PRESENT bit is bit 4, we can use the bits above */
+
+#define __swp_type(x)                   (((x).val >> 5) & 0x7f)
+#define __swp_offset(x)                 ((x).val >> 12)
+#define __swp_entry(type, offset)       ((swp_entry_t) { ((type) << 5) | ((offset) << 12) })
+#define __pte_to_swp_entry(pte)         ((swp_entry_t) { pte_val(pte) })
+#define __swp_entry_to_pte(x)           ((pte_t) { (x).val })
+
+#define kern_addr_valid(addr)   (1)
+
+#include <asm-generic/pgtable.h>
+
+/*
+ * No page table caches to initialise
+ */
+#define pgtable_cache_init()   do { } while (0)
+
+#define pte_to_pgoff(x) (pte_val(x) >> 6)
+#define pgoff_to_pte(x) __pte(((x) << 6) | _PAGE_FILE)
+
+typedef pte_t *pte_addr_t;
+
+#endif /* __ASSEMBLY__ */
+#endif /* _CRIS_PGTABLE_H */