[linux-2.6-block.git] / arch / arm / mm / pgd.c

/*
 *  linux/arch/arm/mm/pgd.c
 *
 *  Copyright (C) 1998-2005 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/mm.h>
#include <linux/gfp.h>
#include <linux/highmem.h>

#include <asm/pgalloc.h>
#include <asm/page.h>
#include <asm/tlbflush.h>

#include "mm.h"

#define FIRST_KERNEL_PGD_NR	(FIRST_USER_PGD_NR + USER_PTRS_PER_PGD)

/*
 * need to get a 16k page for level 1
 */
pgd_t *get_pgd_slow(struct mm_struct *mm)
{
	pgd_t *new_pgd, *init_pgd;
	pmd_t *new_pmd, *init_pmd;
	pte_t *new_pte, *init_pte;

	new_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, 2);
	if (!new_pgd)
		goto no_pgd;

	memset(new_pgd, 0, FIRST_KERNEL_PGD_NR * sizeof(pgd_t));

	/*
	 * Copy over the kernel and IO PGD entries
	 */
	init_pgd = pgd_offset_k(0);
	memcpy(new_pgd + FIRST_KERNEL_PGD_NR, init_pgd + FIRST_KERNEL_PGD_NR,
		       (PTRS_PER_PGD - FIRST_KERNEL_PGD_NR) * sizeof(pgd_t));

	clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t));

	if (!vectors_high()) {
		/*
		 * On ARM, first page must always be allocated since it
		 * contains the machine vectors.
		 */
		new_pmd = pmd_alloc(mm, new_pgd, 0);
		if (!new_pmd)
			goto no_pmd;

		new_pte = pte_alloc_map(mm, new_pmd, 0);
		if (!new_pte)
			goto no_pte;

		init_pmd = pmd_offset(init_pgd, 0);
		init_pte = pte_offset_map_nested(init_pmd, 0);
		set_pte_ext(new_pte, *init_pte, 0);
		pte_unmap_nested(init_pte);
		pte_unmap(new_pte);
	}

	return new_pgd;

no_pte:
	pmd_free(mm, new_pmd);
no_pmd:
	free_pages((unsigned long)new_pgd, 2);
no_pgd:
	return NULL;
}

void free_pgd_slow(struct mm_struct *mm, pgd_t *pgd)
{
	pmd_t *pmd;
	pgtable_t pte;

	if (!pgd)
		return;

	/* pgd is always present and good */
	pmd = pmd_off(pgd, 0);
	if (pmd_none(*pmd))
		goto free;
	if (pmd_bad(*pmd)) {
		pmd_ERROR(*pmd);
		pmd_clear(pmd);
		goto free;
	}

	pte = pmd_pgtable(*pmd);
	pmd_clear(pmd);
	pte_free(mm, pte);
	pmd_free(mm, pmd);
free:
	free_pages((unsigned long) pgd, 2);
}
Commit	Line	Data
1da177e4	1	/*
0c668984	2	* linux/arch/arm/mm/pgd.c
1da177e4	3	*
90072059	4	* Copyright (C) 1998-2005 Russell King
1da177e4 LT	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 as
	8	* published by the Free Software Foundation.
1da177e4	9	*/
1da177e4	10	#include <linux/mm.h>
5a0e3ad6	11	#include <linux/gfp.h>
1da177e4	12	#include <linux/highmem.h>
1da177e4 LT	13
	14	#include <asm/pgalloc.h>
	15	#include <asm/page.h>
1da177e4 LT	16	#include <asm/tlbflush.h>
1da177e4 LT	17
1b2e2b73 RK	18	#include "mm.h"
1b2e2b73 RK	19
1da177e4 LT	20	#define FIRST_KERNEL_PGD_NR (FIRST_USER_PGD_NR + USER_PTRS_PER_PGD)
	21
	22	/*
	23	* need to get a 16k page for level 1
	24	*/
	25	pgd_t get_pgd_slow(struct mm_struct mm)
	26	{
	27	pgd_t new_pgd, init_pgd;
	28	pmd_t new_pmd, init_pmd;
	29	pte_t new_pte, init_pte;
	30
	31	new_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, 2);
	32	if (!new_pgd)
	33	goto no_pgd;
	34
59f0cb0f	35	memset(new_pgd, 0, FIRST_KERNEL_PGD_NR * sizeof(pgd_t));
1da177e4	36
a343e607 RK	37	/*
	38	* Copy over the kernel and IO PGD entries
	39	*/
1da177e4	40	init_pgd = pgd_offset_k(0);
a343e607 RK	41	memcpy(new_pgd + FIRST_KERNEL_PGD_NR, init_pgd + FIRST_KERNEL_PGD_NR,
	42	(PTRS_PER_PGD - FIRST_KERNEL_PGD_NR) * sizeof(pgd_t));
	43
	44	clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t));
1da177e4 LT	45
1da177e4 LT	46	if (!vectors_high()) {
1da177e4 LT	47	/*
	48	* On ARM, first page must always be allocated since it
	49	* contains the machine vectors.
	50	*/
	51	new_pmd = pmd_alloc(mm, new_pgd, 0);
	52	if (!new_pmd)
	53	goto no_pmd;
	54
	55	new_pte = pte_alloc_map(mm, new_pmd, 0);
	56	if (!new_pte)
	57	goto no_pte;
	58
	59	init_pmd = pmd_offset(init_pgd, 0);
	60	init_pte = pte_offset_map_nested(init_pmd, 0);
ad1ae2fe	61	set_pte_ext(new_pte, *init_pte, 0);
1da177e4 LT	62	pte_unmap_nested(init_pte);
1da177e4 LT	63	pte_unmap(new_pte);
1da177e4 LT	64	}
1da177e4 LT	65
1da177e4 LT	66	return new_pgd;
	67
	68	no_pte:
5e541973	69	pmd_free(mm, new_pmd);
1da177e4	70	no_pmd:
1da177e4	71	free_pages((unsigned long)new_pgd, 2);
1da177e4 LT	72	no_pgd:
	73	return NULL;
	74	}
	75
5e541973	76	void free_pgd_slow(struct mm_struct mm, pgd_t pgd)
1da177e4 LT	77	{
1da177e4 LT	78	pmd_t *pmd;
0c82d83c	79	pgtable_t pte;
1da177e4 LT	80
	81	if (!pgd)
	82	return;
	83
	84	/* pgd is always present and good */
155bb144	85	pmd = pmd_off(pgd, 0);
1da177e4 LT	86	if (pmd_none(*pmd))
	87	goto free;
	88	if (pmd_bad(*pmd)) {
	89	pmd_ERROR(*pmd);
	90	pmd_clear(pmd);
	91	goto free;
	92	}
	93
0c82d83c	94	pte = pmd_pgtable(*pmd);
1da177e4	95	pmd_clear(pmd);
5e541973 BH	96	pte_free(mm, pte);
5e541973 BH	97	pmd_free(mm, pmd);
1da177e4 LT	98	free:
	99	free_pages((unsigned long) pgd, 2);
	100	}