LXR linux/arch/hexagon/include/asm/pgalloc.h

   1/*
   2 * Page table support for the Hexagon architecture
   3 *
   4 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License version 2 and
   8 * only version 2 as published by the Free Software Foundation.
   9 *
  10 * This program is distributed in the hope that it will be useful,
  11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 * GNU General Public License for more details.
  14 *
  15 * You should have received a copy of the GNU General Public License
  16 * along with this program; if not, write to the Free Software
  17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  18 * 02110-1301, USA.
  19 */
  20
  21#ifndef _ASM_PGALLOC_H
  22#define _ASM_PGALLOC_H
  23
  24#include <asm/mem-layout.h>
  25#include <asm/atomic.h>
  26
  27#define check_pgt_cache() do {} while (0)
  28
  29extern unsigned long long kmap_generation;
  30
  31/*
  32 * Page table creation interface
  33 */
  34static inline pgd_t *pgd_alloc(struct mm_struct *mm)
  35{
  36        pgd_t *pgd;
  37
  38        pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
  39
  40        /*
  41         * There may be better ways to do this, but to ensure
  42         * that new address spaces always contain the kernel
  43         * base mapping, and to ensure that the user area is
  44         * initially marked invalid, initialize the new map
  45         * map with a copy of the kernel's persistent map.
  46         */
  47
  48        memcpy(pgd, swapper_pg_dir, PTRS_PER_PGD*sizeof(pgd_t));
  49        mm->context.generation = kmap_generation;
  50
  51        /* Physical version is what is passed to virtual machine on switch */
  52        mm->context.ptbase = __pa(pgd);
  53
  54        return pgd;
  55}
  56
  57static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
  58{
  59        free_page((unsigned long) pgd);
  60}
  61
  62static inline struct page *pte_alloc_one(struct mm_struct *mm,
  63                                         unsigned long address)
  64{
  65        struct page *pte;
  66
  67        pte = alloc_page(GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO);
  68        if (!pte)
  69                return NULL;
  70        if (!pgtable_page_ctor(pte)) {
  71                __free_page(pte);
  72                return NULL;
  73        }
  74        return pte;
  75}
  76
  77/* _kernel variant gets to use a different allocator */
  78static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
  79                                          unsigned long address)
  80{
  81        gfp_t flags =  GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO;
  82        return (pte_t *) __get_free_page(flags);
  83}
  84
  85static inline void pte_free(struct mm_struct *mm, struct page *pte)
  86{
  87        pgtable_page_dtor(pte);
  88        __free_page(pte);
  89}
  90
  91static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
  92{
  93        free_page((unsigned long)pte);
  94}
  95
  96static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
  97                                pgtable_t pte)
  98{
  99        /*
 100         * Conveniently, zero in 3 LSB means indirect 4K page table.
 101         * Not so convenient when you're trying to vary the page size.
 102         */
 103        set_pmd(pmd, __pmd(((unsigned long)page_to_pfn(pte) << PAGE_SHIFT) |
 104                HEXAGON_L1_PTE_SIZE));
 105}
 106
 107/*
 108 * Other architectures seem to have ways of making all processes
 109 * share the same pmd's for their kernel mappings, but the v0.3
 110 * Hexagon VM spec has a "monolithic" L1 table for user and kernel
 111 * segments.  We track "generations" of the kernel map to minimize
 112 * overhead, and update the "slave" copies of the kernel mappings
 113 * as part of switch_mm.  However, we still need to update the
 114 * kernel map of the active thread who's calling pmd_populate_kernel...
 115 */
 116static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd,
 117                                       pte_t *pte)
 118{
 119        extern spinlock_t kmap_gen_lock;
 120        pmd_t *ppmd;
 121        int pmdindex;
 122
 123        spin_lock(&kmap_gen_lock);
 124        kmap_generation++;
 125        mm->context.generation = kmap_generation;
 126        current->active_mm->context.generation = kmap_generation;
 127        spin_unlock(&kmap_gen_lock);
 128
 129        set_pmd(pmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE));
 130
 131        /*
 132         * Now the "slave" copy of the current thread.
 133         * This is pointer arithmetic, not byte addresses!
 134         */
 135        pmdindex = (pgd_t *)pmd - mm->pgd;
 136        ppmd = (pmd_t *)current->active_mm->pgd + pmdindex;
 137        set_pmd(ppmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE));
 138        if (pmdindex > max_kernel_seg)
 139                max_kernel_seg = pmdindex;
 140}
 141
 142#define __pte_free_tlb(tlb, pte, addr)          \
 143do {                                            \
 144        pgtable_page_dtor((pte));               \
 145        tlb_remove_page((tlb), (pte));          \
 146} while (0)
 147
 148#endif
 149