[PATCH] shared page table for hugetlb page

[linux.git] / arch / sh / mm / hugetlbpage.c

/*
 * arch/sh/mm/hugetlbpage.c
 *
 * SuperH HugeTLB page support.
 *
 * Cloned from sparc64 by Paul Mundt.
 *
 * Copyright (C) 2002, 2003 David S. Miller ([email protected])
 */

#include <linux/init.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/pagemap.h>
#include <linux/smp_lock.h>
#include <linux/slab.h>
#include <linux/sysctl.h>

#include <asm/mman.h>
#include <asm/pgalloc.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/cacheflush.h>

pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr)
{
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte = NULL;

	pgd = pgd_offset(mm, addr);
	if (pgd) {
		pud = pud_alloc(mm, pgd, addr);
		if (pud) {
			pmd = pmd_alloc(mm, pud, addr);
			if (pmd)
				pte = pte_alloc_map(mm, pmd, addr);
		}
	}

	return pte;
}

pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
{
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte = NULL;

	pgd = pgd_offset(mm, addr);
	if (pgd) {
		pud = pud_offset(pgd, addr);
		if (pud) {
			pmd = pmd_offset(pud, addr);
			if (pmd)
				pte = pte_offset_map(pmd, addr);
		}
	}

	return pte;
}

int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
{
	return 0;
}

struct page *follow_huge_addr(struct mm_struct *mm,
			      unsigned long address, int write)
{
	return ERR_PTR(-EINVAL);
}

int pmd_huge(pmd_t pmd)
{
	return 0;
}

struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
			     pmd_t *pmd, int write)
{
	return NULL;
}