forked from mirrors/linux
cbd15b3fad
This patch adds support for page table management. Signed-off-by: Ley Foon Tan <lftan@altera.com>
74 lines
1.7 KiB
C
74 lines
1.7 KiB
C
/*
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* Copyright (C) 2009 Wind River Systems Inc
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* Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#include <linux/mm.h>
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#include <linux/sched.h>
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#include <asm/pgtable.h>
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#include <asm/cpuinfo.h>
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/* pteaddr:
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* ptbase | vpn* | zero
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* 31-22 | 21-2 | 1-0
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*
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* *vpn is preserved on double fault
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*
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* tlbacc:
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* IG |*flags| pfn
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* 31-25|24-20 | 19-0
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*
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* *crwxg
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*
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* tlbmisc:
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* resv |way |rd | we|pid |dbl|bad|perm|d
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* 31-24 |23-20 |19 | 20|17-4|3 |2 |1 |0
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*
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*/
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/*
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* Initialize a new pgd / pmd table with invalid pointers.
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*/
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static void pgd_init(pgd_t *pgd)
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{
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unsigned long *p = (unsigned long *) pgd;
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int i;
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for (i = 0; i < USER_PTRS_PER_PGD; i += 8) {
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p[i + 0] = (unsigned long) invalid_pte_table;
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p[i + 1] = (unsigned long) invalid_pte_table;
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p[i + 2] = (unsigned long) invalid_pte_table;
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p[i + 3] = (unsigned long) invalid_pte_table;
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p[i + 4] = (unsigned long) invalid_pte_table;
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p[i + 5] = (unsigned long) invalid_pte_table;
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p[i + 6] = (unsigned long) invalid_pte_table;
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p[i + 7] = (unsigned long) invalid_pte_table;
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}
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}
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pgd_t *pgd_alloc(struct mm_struct *mm)
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{
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pgd_t *ret, *init;
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ret = (pgd_t *) __get_free_pages(GFP_KERNEL, PGD_ORDER);
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if (ret) {
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init = pgd_offset(&init_mm, 0UL);
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pgd_init(ret);
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memcpy(ret + USER_PTRS_PER_PGD, init + USER_PTRS_PER_PGD,
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(PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
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}
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return ret;
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}
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void __init pagetable_init(void)
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{
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/* Initialize the entire pgd. */
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pgd_init(swapper_pg_dir);
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pgd_init(swapper_pg_dir + USER_PTRS_PER_PGD);
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}
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