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nios2: Page table management

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This patch adds support for page table management.

Signed-off-by: Ley Foon Tan <lftan@altera.com>
This commit is contained in:
Ley Foon Tan 2014-11-06 15:19:45 +08:00
parent 862674d424
commit cbd15b3fad
4 changed files with 505 additions and 0 deletions
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74
arch/nios2/mm/pgtable.c Normal file
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/*
* Copyright (C) 2009 Wind River Systems Inc
* Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/mm.h>
#include <linux/sched.h>
#include <asm/pgtable.h>
#include <asm/cpuinfo.h>
/* pteaddr:
* ptbase | vpn* | zero
* 31-22 | 21-2 | 1-0
*
* *vpn is preserved on double fault
*
* tlbacc:
* IG |*flags| pfn
* 31-25|24-20 | 19-0
*
* *crwxg
*
* tlbmisc:
* resv |way |rd | we|pid |dbl|bad|perm|d
* 31-24 |23-20 |19 | 20|17-4|3 |2 |1 |0
*
*/
/*
* Initialize a new pgd / pmd table with invalid pointers.
*/
static void pgd_init(pgd_t *pgd)
{
unsigned long *p = (unsigned long *) pgd;
int i;
for (i = 0; i < USER_PTRS_PER_PGD; i += 8) {
p[i + 0] = (unsigned long) invalid_pte_table;
p[i + 1] = (unsigned long) invalid_pte_table;
p[i + 2] = (unsigned long) invalid_pte_table;
p[i + 3] = (unsigned long) invalid_pte_table;
p[i + 4] = (unsigned long) invalid_pte_table;
p[i + 5] = (unsigned long) invalid_pte_table;
p[i + 6] = (unsigned long) invalid_pte_table;
p[i + 7] = (unsigned long) invalid_pte_table;
}
}
pgd_t *pgd_alloc(struct mm_struct *mm)
{
pgd_t *ret, *init;
ret = (pgd_t *) __get_free_pages(GFP_KERNEL, PGD_ORDER);
if (ret) {
init = pgd_offset(&init_mm, 0UL);
pgd_init(ret);
memcpy(ret + USER_PTRS_PER_PGD, init + USER_PTRS_PER_PGD,
(PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
}
return ret;
}
void __init pagetable_init(void)
{
/* Initialize the entire pgd. */
pgd_init(swapper_pg_dir);
pgd_init(swapper_pg_dir + USER_PTRS_PER_PGD);
}