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/cpuinfo.h>
14
15/* pteaddr:
16 *   ptbase | vpn* | zero
17 *   31-22  | 21-2 | 1-0
18 *
19 *   *vpn is preserved on double fault
20 *
21 * tlbacc:
22 *   IG   |*flags| pfn
23 *   31-25|24-20 | 19-0
24 *
25 *   *crwxg
26 *
27 * tlbmisc:
28 *   resv  |way   |rd | we|pid |dbl|bad|perm|d
29 *   31-24 |23-20 |19 | 20|17-4|3  |2  |1   |0
30 *
31 */
32
33/*
34 * Initialize a new pgd / pmd table with invalid pointers.
35 */
36static void pgd_init(pgd_t *pgd)
37{
38	unsigned long *p = (unsigned long *) pgd;
39	int i;
40
41	for (i = 0; i < USER_PTRS_PER_PGD; i += 8) {
42		p[i + 0] = (unsigned long) invalid_pte_table;
43		p[i + 1] = (unsigned long) invalid_pte_table;
44		p[i + 2] = (unsigned long) invalid_pte_table;
45		p[i + 3] = (unsigned long) invalid_pte_table;
46		p[i + 4] = (unsigned long) invalid_pte_table;
47		p[i + 5] = (unsigned long) invalid_pte_table;
48		p[i + 6] = (unsigned long) invalid_pte_table;
49		p[i + 7] = (unsigned long) invalid_pte_table;
50	}
51}
52
53pgd_t *pgd_alloc(struct mm_struct *mm)
54{
55	pgd_t *ret, *init;
56
57	ret = (pgd_t *) __get_free_page(GFP_KERNEL);
58	if (ret) {
59		init = pgd_offset(&init_mm, 0UL);
60		pgd_init(ret);
61		memcpy(ret + USER_PTRS_PER_PGD, init + USER_PTRS_PER_PGD,
62		       (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
63	}
64
65	return ret;
66}
67
68void __init pagetable_init(void)
69{
70	/* Initialize the entire pgd.  */
71	pgd_init(swapper_pg_dir);
72	pgd_init(swapper_pg_dir + USER_PTRS_PER_PGD);
73}
74