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/* MN10300 Page table manipulators and constants
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
* The Linux memory management assumes a three-level page table setup. On
* the i386, we use that, but "fold" the mid level into the top-level page
* table, so that we physically have the same two-level page table as the
* i386 mmu expects.
* This file contains the functions and defines necessary to modify and use
* the i386 page table tree for the purposes of the MN10300 TLB handler
* functions.
#ifndef _ASM_PGTABLE_H
#define _ASM_PGTABLE_H
#include <asm/cpu-regs.h>
#ifndef __ASSEMBLY__
#include <asm/processor.h>
#include <asm/cache.h>
#include <linux/threads.h>
#include <asm/bitops.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/spinlock.h>
* ZERO_PAGE is a global shared page that is always zero: used
* for zero-mapped memory areas etc..
#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
extern unsigned long empty_zero_page[1024];
extern spinlock_t pgd_lock;
extern struct page *pgd_list;
extern void pmd_ctor(void *, struct kmem_cache *, unsigned long);
extern void pgtable_cache_init(void);
extern void paging_init(void);
#endif /* !__ASSEMBLY__ */
* The Linux mn10300 paging architecture only implements both the traditional
* 2-level page tables
#define PGDIR_SHIFT 22
#define PTRS_PER_PGD 1024
#define PTRS_PER_PUD 1 /* we don't really have any PUD physically */
#define PTRS_PER_PMD 1 /* we don't really have any PMD physically */
#define PTRS_PER_PTE 1024
#define PMD_SIZE (1UL << PMD_SHIFT)
#define PGDIR_MASK (~(PGDIR_SIZE - 1))
#ifndef __ASSEMBLY__
extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
* Unfortunately, due to the way the MMU works on the MN10300, the vmalloc VM
* area has to be in the lower half of the virtual address range (the upper
* half is not translated through the TLB).
* So in this case, the vmalloc area goes at the bottom of the address map
* (leaving a hole at the very bottom to catch addressing errors), and
* userspace starts immediately above.
* The vmalloc() routines also leaves a hole of 4kB between each vmalloced
* area to catch addressing errors.
#define VMALLOC_OFFSET (8 * 1024 * 1024)
#define VMALLOC_START (0x70000000)
#define VMALLOC_END (0x7C000000)
#ifndef __ASSEMBLY__
extern pte_t kernel_vmalloc_ptes[(VMALLOC_END - VMALLOC_START) / PAGE_SIZE];
/* IPTEL/DPTEL bit assignments */
#define _PAGE_BIT_ACCESSED xPTEL_UNUSED1_BIT /* mustn't be loaded into IPTEL/DPTEL */
#define _PAGE_BIT_NX xPTEL_UNUSED2_BIT /* mustn't be loaded into IPTEL/DPTEL */
#define _PAGE_NX xPTEL_UNUSED2 /* no-execute bit */
#define _PAGE_PSE xPTEL_PS_4Mb /* 4MB page */
#define _PAGE_FILE xPTEL_UNUSED1_BIT /* set:pagecache unset:swap */
#define __PAGE_PROT_UWAUX 0x040
#define __PAGE_PROT_USER 0x080
#define __PAGE_PROT_WRITE 0x100
#define _PAGE_PROTNONE 0x000 /* If not present */
#ifndef __ASSEMBLY__
#define VMALLOC_VMADDR(x) ((unsigned long)(x))
#define PAGE_NONE __pgprot(__PAGE_NONE | _PAGE_NX)
#define PAGE_COPY_NOEXEC __pgprot(__PAGE_COPY | _PAGE_NX)
#define PAGE_SHARED_EXEC __pgprot(__PAGE_SHARED)
#define PAGE_COPY_EXEC __pgprot(__PAGE_COPY)
#define PAGE_KERNEL __pgprot(__PAGE_KERNEL)
#define PAGE_KERNEL_RO __pgprot(__PAGE_KERNEL_RO)
* Whilst the MN10300 can do page protection for execute (given separate data
* and insn TLBs), we are not supporting it at the moment. Write permission,
* however, always implies read permission (but not execute permission).
#define __P000 PAGE_NONE
#define __P010 PAGE_COPY_NOEXEC
#define __P011 PAGE_COPY_NOEXEC
#define __P110 PAGE_COPY_EXEC
#define __P111 PAGE_COPY_EXEC
#define __S000 PAGE_NONE
#define __S110 PAGE_SHARED_EXEC
#define __S111 PAGE_SHARED_EXEC
* Define this to warn about kernel memory accesses that are
* done without a 'verify_area(VERIFY_WRITE,..)'
#define pte_present(x) (pte_val(x) & _PAGE_VALID)
#define pte_clear(mm, addr, xp) \
do { \
set_pte_at((mm), (addr), (xp), __pte(0)); \
} while (0)
#define pmd_none(x) (!pmd_val(x))
#define pmd_present(x) (!pmd_none(x))
#define pmd_clear(xp) do { set_pmd(xp, __pmd(0)); } while (0)
#define pmd_bad(x) 0
#define pages_to_mb(x) ((x) >> (20 - PAGE_SHIFT))
#ifndef __ASSEMBLY__
* The following only work if pte_present() is true.
* Undefined behaviour if not..
static inline int pte_user(pte_t pte) { return pte_val(pte) & __PAGE_PROT_USER; }
static inline int pte_read(pte_t pte) { return pte_val(pte) & __PAGE_PROT_USER; }
static inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; }
static inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; }
static inline int pte_write(pte_t pte) { return pte_val(pte) & __PAGE_PROT_WRITE; }
* The following only works if pte_present() is not true.
static inline int pte_file(pte_t pte) { return pte_val(pte) & _PAGE_FILE; }
static inline pte_t pte_rdprotect(pte_t pte)
pte_val(pte) &= ~(__PAGE_PROT_USER|__PAGE_PROT_UWAUX); return pte;
static inline pte_t pte_exprotect(pte_t pte)
pte_val(pte) |= _PAGE_NX; return pte;
static inline pte_t pte_wrprotect(pte_t pte)
pte_val(pte) &= ~(__PAGE_PROT_WRITE|__PAGE_PROT_UWAUX); return pte;
static inline pte_t pte_mkclean(pte_t pte) { pte_val(pte) &= ~_PAGE_DIRTY; return pte; }
static inline pte_t pte_mkold(pte_t pte) { pte_val(pte) &= ~_PAGE_ACCESSED; return pte; }
static inline pte_t pte_mkdirty(pte_t pte) { pte_val(pte) |= _PAGE_DIRTY; return pte; }
static inline pte_t pte_mkyoung(pte_t pte) { pte_val(pte) |= _PAGE_ACCESSED; return pte; }
static inline pte_t pte_mkexec(pte_t pte) { pte_val(pte) &= ~_PAGE_NX; return pte; }
static inline pte_t pte_mkread(pte_t pte)
pte_val(pte) |= __PAGE_PROT_USER;
if (pte_write(pte))
pte_val(pte) |= __PAGE_PROT_UWAUX;
return pte;
static inline pte_t pte_mkwrite(pte_t pte)
pte_val(pte) |= __PAGE_PROT_WRITE;
if (pte_val(pte) & __PAGE_PROT_USER)
pte_val(pte) |= __PAGE_PROT_UWAUX;
return pte;
#define pte_ERROR(e) \
printk(KERN_ERR "%s:%d: bad pte %08lx.\n", \
__FILE__, __LINE__, pte_val(e))
#define pgd_ERROR(e) \
printk(KERN_ERR "%s:%d: bad pgd %08lx.\n", \
__FILE__, __LINE__, pgd_val(e))
* The "pgd_xxx()" functions here are trivial for a folded two-level
* setup: the pgd is never bad, and a pmd always exists (as it's folded
* into the pgd entry)
#define pgd_clear(xp) do { } while (0)
* Certain architectures need to do special things when PTEs
* 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))
#define set_pte_atomic(pteptr, pteval) set_pte((pteptr), (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 ptep_get_and_clear(mm, addr, ptep) \
__pte(xchg(&(ptep)->pte, 0))
#define pte_same(a, b) (pte_val(a) == pte_val(b))
#define pte_page(x) pfn_to_page(pte_pfn(x))
#define pte_none(x) (!pte_val(x))
#define pte_pfn(x) ((unsigned long) (pte_val(x) >> PAGE_SHIFT))
#define __pfn_addr(pfn) ((pfn) << PAGE_SHIFT)
#define pfn_pte(pfn, prot) __pte(__pfn_addr(pfn) | pgprot_val(prot))
#define pfn_pmd(pfn, prot) __pmd(__pfn_addr(pfn) | pgprot_val(prot))
* All present user pages are user-executable:
static inline int pte_exec(pte_t pte)
return pte_user(pte);
* All present pages are kernel-executable:
static inline int pte_exec_kernel(pte_t pte)
return 1;
* Bits 0 and 1 are taken, split up the 29 bits of offset
* into this range:
#define PTE_FILE_MAX_BITS 29
#define pte_to_pgoff(pte) (pte_val(pte) >> 2)
#define pgoff_to_pte(off) __pte((off) << 2 | _PAGE_FILE)
/* Encode and de-code a swap entry */
#define __swp_type(x) (((x).val >> 2) & 0x3f)
#define __swp_offset(x) ((x).val >> 8)
#define __swp_entry(type, offset) \
((swp_entry_t) { ((type) << 2) | ((offset) << 8) })
#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
#define __swp_entry_to_pte(x) __pte((x).val)
static inline
int ptep_test_and_clear_dirty(struct vm_area_struct *vma, unsigned long addr,
pte_t *ptep)
if (!pte_dirty(*ptep))
return 0;
return test_and_clear_bit(_PAGE_BIT_DIRTY, &ptep->pte);
static inline
int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr,
pte_t *ptep)
if (!pte_young(*ptep))
return 0;
return test_and_clear_bit(_PAGE_BIT_ACCESSED, &ptep->pte);
static inline
void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
pte_val(*ptep) &= ~(__PAGE_PROT_WRITE|__PAGE_PROT_UWAUX);
static inline void ptep_mkdirty(pte_t *ptep)
set_bit(_PAGE_BIT_DIRTY, &ptep->pte);
* Macro to mark a page protection value as "uncacheable". On processors which
* do not support it, this is a no-op.
#define pgprot_noncached(prot) __pgprot(pgprot_val(prot) | _PAGE_CACHE)
* Conversion functions: convert a page and protection to a page entry,
* and a page entry and page directory to the page they refer to.
#define mk_pte(page, pgprot) pfn_pte(page_to_pfn(page), (pgprot))
#define mk_pte_huge(entry) \
((entry).pte |= _PAGE_PRESENT | _PAGE_PSE | _PAGE_VALID)
static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
pte_val(pte) &= _PAGE_CHG_MASK;
pte_val(pte) |= pgprot_val(newprot);
return pte;
#define page_pte(page) page_pte_prot((page), __pgprot(0))
#define pmd_page_kernel(pmd) \
((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
#define pmd_page(pmd) pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT)
#define pmd_large(pmd) \
((pmd_val(pmd) & (_PAGE_PSE | _PAGE_PRESENT)) == \
* the pgd page can be thought of an array like this: pgd_t[PTRS_PER_PGD]
* this macro returns the index of the entry in the pgd page which would
* control the given virtual address
#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
* pgd_offset() returns a (pgd_t *)
* pgd_index() is used get the offset into the pgd page's array of pgd_t's;
#define pgd_offset(mm, address) ((mm)->pgd + pgd_index(address))
* a shortcut which implies the use of the kernel's pgd, instead
* of a process's
#define pgd_offset_k(address) pgd_offset(&init_mm, address)
* the pmd page can be thought of an array like this: pmd_t[PTRS_PER_PMD]
* this macro returns the index of the entry in the pmd page which would
* control the given virtual address
#define pmd_index(address) \
(((address) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))
* the pte page can be thought of an array like this: pte_t[PTRS_PER_PTE]
* this macro returns the index of the entry in the pte page which would
* control the given virtual address
#define pte_index(address) \
(((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
#define pte_offset_kernel(dir, address) \
((pte_t *) pmd_page_kernel(*(dir)) + pte_index(address))
* Make a given kernel text page executable/non-executable.
* Returns the previous executability setting of that page (which
* is used to restore the previous state). Used by the SMP bootup code.
* NOTE: this is an __init function for security reasons.
static inline int set_kernel_exec(unsigned long vaddr, int enable)
return 0;
#define pte_offset_map(dir, address) \
((pte_t *) page_address(pmd_page(*(dir))) + pte_index(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)
* The MN10300 has external MMU info in the form of a TLB: this is adapted from
* the kernel page tables containing the necessary information by tlb-mn10300.S
extern void update_mmu_cache(struct vm_area_struct *vma,
unsigned long address, pte_t pte);
#endif /* !__ASSEMBLY__ */
#define kern_addr_valid(addr) (1)
#define io_remap_pfn_range(vma, vaddr, pfn, size, prot) \
remap_pfn_range((vma), (vaddr), (pfn), (size), (prot))
#define MK_IOSPACE_PFN(space, pfn) (pfn)
#define GET_IOSPACE(pfn) 0
#define GET_PFN(pfn) (pfn)
#include <asm-generic/pgtable.h>
#endif /* !__ASSEMBLY__ */
#endif /* _ASM_PGTABLE_H */