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);
72	mm_dec_nr_pmds(mm);
73no_pmd:
74	free_pages((unsigned long)new_pgd, 0);
75no_pgd:
76	return NULL;
77}
78
79void free_pgd_slow(struct mm_struct *mm, pgd_t *pgd)
80{
81	pmd_t *pmd;
82	pgtable_t pte;
83
84	if (!pgd)
85		return;
86
87	/* pgd is always present and good */
88	pmd = pmd_off(pgd, 0);
89	if (pmd_none(*pmd))
90		goto free;
91	if (pmd_bad(*pmd)) {
92		pmd_ERROR(*pmd);
93		pmd_clear(pmd);
94		goto free;
95	}
96
97	pte = pmd_pgtable(*pmd);
98	pmd_clear(pmd);
99	pte_free(mm, pte);
100	atomic_long_dec(&mm->nr_ptes);
101	pmd_free(mm, pmd);
102	mm_dec_nr_pmds(mm);
103free:
104	free_pages((unsigned long) pgd, 0);
105}
106