1/*
2 * Copyright (C) 2009 Wind River Systems Inc
3 *   Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
4 *
5 * This file is subject to the terms and conditions of the GNU General Public
6 * License.  See the file "COPYING" in the main directory of this archive
7 * for more details.
8 */
9
10#include <linux/mm.h>
11#include <linux/sched.h>
12
13#include <asm/pgtable.h>
14#include <asm/cpuinfo.h>
15
16/* pteaddr:
17 *   ptbase | vpn* | zero
18 *   31-22  | 21-2 | 1-0
19 *
20 *   *vpn is preserved on double fault
21 *
22 * tlbacc:
23 *   IG   |*flags| pfn
24 *   31-25|24-20 | 19-0
25 *
26 *   *crwxg
27 *
28 * tlbmisc:
29 *   resv  |way   |rd | we|pid |dbl|bad|perm|d
30 *   31-24 |23-20 |19 | 20|17-4|3  |2  |1   |0
31 *
32 */
33
34/*
35 * Initialize a new pgd / pmd table with invalid pointers.
36 */
37static void pgd_init(pgd_t *pgd)
38{
39	unsigned long *p = (unsigned long *) pgd;
40	int i;
41
42	for (i = 0; i < USER_PTRS_PER_PGD; i += 8) {
43		p[i + 0] = (unsigned long) invalid_pte_table;
44		p[i + 1] = (unsigned long) invalid_pte_table;
45		p[i + 2] = (unsigned long) invalid_pte_table;
46		p[i + 3] = (unsigned long) invalid_pte_table;
47		p[i + 4] = (unsigned long) invalid_pte_table;
48		p[i + 5] = (unsigned long) invalid_pte_table;
49		p[i + 6] = (unsigned long) invalid_pte_table;
50		p[i + 7] = (unsigned long) invalid_pte_table;
51	}
52}
53
54pgd_t *pgd_alloc(struct mm_struct *mm)
55{
56	pgd_t *ret, *init;
57
58	ret = (pgd_t *) __get_free_pages(GFP_KERNEL, PGD_ORDER);
59	if (ret) {
60		init = pgd_offset(&init_mm, 0UL);
61		pgd_init(ret);
62		memcpy(ret + USER_PTRS_PER_PGD, init + USER_PTRS_PER_PGD,
63		       (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
64	}
65
66	return ret;
67}
68
69void __init pagetable_init(void)
70{
71	/* Initialize the entire pgd.  */
72	pgd_init(swapper_pg_dir);
73	pgd_init(swapper_pg_dir + USER_PTRS_PER_PGD);
74}
75