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 */
36 static 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
53 pgd_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
68 void __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
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