LXR linux/arch/mn10300/mm/pgtable.c

   1/* MN10300 Page table management
   2 *
   3 * Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd.
   4 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   5 * Modified by David Howells (dhowells@redhat.com)
   6 *
   7 * This program is free software; you can redistribute it and/or
   8 * modify it under the terms of the GNU General Public Licence
   9 * as published by the Free Software Foundation; either version
  10 * 2 of the Licence, or (at your option) any later version.
  11 */
  12#include <linux/sched.h>
  13#include <linux/kernel.h>
  14#include <linux/errno.h>
  15#include <linux/gfp.h>
  16#include <linux/mm.h>
  17#include <linux/swap.h>
  18#include <linux/smp.h>
  19#include <linux/highmem.h>
  20#include <linux/pagemap.h>
  21#include <linux/spinlock.h>
  22#include <linux/quicklist.h>
  23
  24#include <asm/pgtable.h>
  25#include <asm/pgalloc.h>
  26#include <asm/tlb.h>
  27#include <asm/tlbflush.h>
  28
  29/*
  30 * Associate a large virtual page frame with a given physical page frame
  31 * and protection flags for that frame. pfn is for the base of the page,
  32 * vaddr is what the page gets mapped to - both must be properly aligned.
  33 * The pmd must already be instantiated. Assumes PAE mode.
  34 */
  35void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
  36{
  37        pgd_t *pgd;
  38        pud_t *pud;
  39        pmd_t *pmd;
  40
  41        if (vaddr & (PMD_SIZE-1)) {             /* vaddr is misaligned */
  42                printk(KERN_ERR "set_pmd_pfn: vaddr misaligned\n");
  43                return; /* BUG(); */
  44        }
  45        if (pfn & (PTRS_PER_PTE-1)) {           /* pfn is misaligned */
  46                printk(KERN_ERR "set_pmd_pfn: pfn misaligned\n");
  47                return; /* BUG(); */
  48        }
  49        pgd = swapper_pg_dir + pgd_index(vaddr);
  50        if (pgd_none(*pgd)) {
  51                printk(KERN_ERR "set_pmd_pfn: pgd_none\n");
  52                return; /* BUG(); */
  53        }
  54        pud = pud_offset(pgd, vaddr);
  55        pmd = pmd_offset(pud, vaddr);
  56        set_pmd(pmd, pfn_pmd(pfn, flags));
  57        /*
  58         * It's enough to flush this one mapping.
  59         * (PGE mappings get flushed as well)
  60         */
  61        local_flush_tlb_one(vaddr);
  62}
  63
  64pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
  65{
  66        pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT);
  67        if (pte)
  68                clear_page(pte);
  69        return pte;
  70}
  71
  72struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
  73{
  74        struct page *pte;
  75
  76#ifdef CONFIG_HIGHPTE
  77        pte = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM|__GFP_REPEAT, 0);
  78#else
  79        pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT, 0);
  80#endif
  81        if (pte)
  82                clear_highpage(pte);
  83        return pte;
  84}
  85
  86/*
  87 * List of all pgd's needed for non-PAE so it can invalidate entries
  88 * in both cached and uncached pgd's; not needed for PAE since the
  89 * kernel pmd is shared. If PAE were not to share the pmd a similar
  90 * tactic would be needed. This is essentially codepath-based locking
  91 * against pageattr.c; it is the unique case in which a valid change
  92 * of kernel pagetables can't be lazily synchronized by vmalloc faults.
  93 * vmalloc faults work because attached pagetables are never freed.
  94 * If the locking proves to be non-performant, a ticketing scheme with
  95 * checks at dup_mmap(), exec(), and other mmlist addition points
  96 * could be used. The locking scheme was chosen on the basis of
  97 * manfred's recommendations and having no core impact whatsoever.
  98 * -- nyc
  99 */
 100DEFINE_SPINLOCK(pgd_lock);
 101struct page *pgd_list;
 102
 103static inline void pgd_list_add(pgd_t *pgd)
 104{
 105        struct page *page = virt_to_page(pgd);
 106        page->index = (unsigned long) pgd_list;
 107        if (pgd_list)
 108                set_page_private(pgd_list, (unsigned long) &page->index);
 109        pgd_list = page;
 110        set_page_private(page, (unsigned long) &pgd_list);
 111}
 112
 113static inline void pgd_list_del(pgd_t *pgd)
 114{
 115        struct page *next, **pprev, *page = virt_to_page(pgd);
 116        next = (struct page *) page->index;
 117        pprev = (struct page **) page_private(page);
 118        *pprev = next;
 119        if (next)
 120                set_page_private(next, (unsigned long) pprev);
 121}
 122
 123void pgd_ctor(void *pgd)
 124{
 125        unsigned long flags;
 126
 127        if (PTRS_PER_PMD == 1)
 128                spin_lock_irqsave(&pgd_lock, flags);
 129
 130        memcpy((pgd_t *)pgd + USER_PTRS_PER_PGD,
 131                        swapper_pg_dir + USER_PTRS_PER_PGD,
 132                        (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
 133
 134        if (PTRS_PER_PMD > 1)
 135                return;
 136
 137        pgd_list_add(pgd);
 138        spin_unlock_irqrestore(&pgd_lock, flags);
 139        memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
 140}
 141
 142/* never called when PTRS_PER_PMD > 1 */
 143void pgd_dtor(void *pgd)
 144{
 145        unsigned long flags; /* can be called from interrupt context */
 146
 147        spin_lock_irqsave(&pgd_lock, flags);
 148        pgd_list_del(pgd);
 149        spin_unlock_irqrestore(&pgd_lock, flags);
 150}
 151
 152pgd_t *pgd_alloc(struct mm_struct *mm)
 153{
 154        return quicklist_alloc(0, GFP_KERNEL, pgd_ctor);
 155}
 156
 157void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 158{
 159        quicklist_free(0, pgd_dtor, pgd);
 160}
 161
 162void __init pgtable_cache_init(void)
 163{
 164}
 165
 166void check_pgt_cache(void)
 167{
 168        quicklist_trim(0, pgd_dtor, 25, 16);
 169}
 170