/arch/unicore32/mm/pgd.c

  1/*
  2 * linux/arch/unicore32/mm/pgd.c
  3 *
  4 * Code specific to PKUnity SoC and UniCore ISA
  5 *
  6 * Copyright (C) 2001-2010 GUAN Xue-tao
  7 *
  8 * This program is free software; you can redistribute it and/or modify
  9 * it under the terms of the GNU General Public License version 2 as
 10 * published by the Free Software Foundation.
 11 */
 12#include <linux/mm.h>
 13#include <linux/gfp.h>
 14#include <linux/highmem.h>
 15
 16#include <asm/pgalloc.h>
 17#include <asm/page.h>
 18#include <asm/tlbflush.h>
 19
 20#include "mm.h"
 21
 22#define FIRST_KERNEL_PGD_NR	(FIRST_USER_PGD_NR + USER_PTRS_PER_PGD)
 23
 24/*
 25 * need to get a 4k page for level 1
 26 */
 27pgd_t *get_pgd_slow(struct mm_struct *mm)
 28{
 29	pgd_t *new_pgd, *init_pgd;
 30	pmd_t *new_pmd, *init_pmd;
 31	pte_t *new_pte, *init_pte;
 32
 33	new_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, 0);
 34	if (!new_pgd)
 35		goto no_pgd;
 36
 37	memset(new_pgd, 0, FIRST_KERNEL_PGD_NR * sizeof(pgd_t));
 38
 39	/*
 40	 * Copy over the kernel and IO PGD entries
 41	 */
 42	init_pgd = pgd_offset_k(0);
 43	memcpy(new_pgd + FIRST_KERNEL_PGD_NR, init_pgd + FIRST_KERNEL_PGD_NR,
 44		       (PTRS_PER_PGD - FIRST_KERNEL_PGD_NR) * sizeof(pgd_t));
 45
 46	clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t));
 47
 48	if (!vectors_high()) {
 49		/*
 50		 * On UniCore, first page must always be allocated since it
 51		 * contains the machine vectors.
 52		 */
 53		new_pmd = pmd_alloc(mm, (pud_t *)new_pgd, 0);
 54		if (!new_pmd)
 55			goto no_pmd;
 56
 57		new_pte = pte_alloc_map(mm, NULL, new_pmd, 0);
 58		if (!new_pte)
 59			goto no_pte;
 60
 61		init_pmd = pmd_offset((pud_t *)init_pgd, 0);
 62		init_pte = pte_offset_map(init_pmd, 0);
 63		set_pte(new_pte, *init_pte);
 64		pte_unmap(init_pte);
 65		pte_unmap(new_pte);
 66	}
 67
 68	return new_pgd;
 69
 70no_pte:
 71	pmd_free(mm, new_pmd);
 72no_pmd:
 73	free_pages((unsigned long)new_pgd, 0);
 74no_pgd:
 75	return NULL;
 76}
 77
 78void free_pgd_slow(struct mm_struct *mm, pgd_t *pgd)
 79{
 80	pmd_t *pmd;
 81	pgtable_t pte;
 82
 83	if (!pgd)
 84		return;
 85
 86	/* pgd is always present and good */
 87	pmd = pmd_off(pgd, 0);
 88	if (pmd_none(*pmd))
 89		goto free;
 90	if (pmd_bad(*pmd)) {
 91		pmd_ERROR(*pmd);
 92		pmd_clear(pmd);
 93		goto free;
 94	}
 95
 96	pte = pmd_pgtable(*pmd);
 97	pmd_clear(pmd);
 98	pte_free(mm, pte);
 99	pmd_free(mm, pmd);
100free:
101	free_pages((unsigned long) pgd, 0);
102}