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