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// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2005-2017 Andes Technology Corporation
#include <linux/init_task.h>
#include <asm/pgalloc.h>
#define FIRST_KERNEL_PGD_NR (USER_PTRS_PER_PGD)
/*
* need to get a page for level 1
*/
pgd_t *pgd_alloc(struct mm_struct *mm)
{
pgd_t *new_pgd, *init_pgd;
int i;
new_pgd = (pgd_t *) __get_free_pages(GFP_KERNEL, 0);
if (!new_pgd)
return NULL;
for (i = 0; i < PTRS_PER_PGD; i++) {
(*new_pgd) = 1;
new_pgd++;
}
new_pgd -= PTRS_PER_PGD;
init_pgd = pgd_offset_k(0);
memcpy(new_pgd + FIRST_KERNEL_PGD_NR, init_pgd + FIRST_KERNEL_PGD_NR,
(PTRS_PER_PGD - FIRST_KERNEL_PGD_NR) * sizeof(pgd_t));
cpu_dcache_wb_range((unsigned long)new_pgd,
(unsigned long)new_pgd +
PTRS_PER_PGD * sizeof(pgd_t));
inc_zone_page_state(virt_to_page((unsigned long *)new_pgd),
NR_PAGETABLE);
return new_pgd;
}
void pgd_free(struct mm_struct *mm, pgd_t * pgd)
{
pmd_t *pmd;
struct page *pte;
if (!pgd)
return;
pmd = (pmd_t *) pgd;
if (pmd_none(*pmd))
goto free;
if (pmd_bad(*pmd)) {
pmd_ERROR(*pmd);
pmd_clear(pmd);
goto free;
}
pte = pmd_page(*pmd);
pmd_clear(pmd);
dec_zone_page_state(virt_to_page((unsigned long *)pgd), NR_PAGETABLE);
pte_free(mm, pte);
mm_dec_nr_ptes(mm);
pmd_free(mm, pmd);
free:
free_pages((unsigned long)pgd, 0);
}
/*
* In order to soft-boot, we need to insert a 1:1 mapping in place of
* the user-mode pages. This will then ensure that we have predictable
* results when turning the mmu off
*/
void setup_mm_for_reboot(char mode)
{
unsigned long pmdval;
pgd_t *pgd;
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
int i;
if (current->mm && current->mm->pgd)
pgd = current->mm->pgd;
else
pgd = init_mm.pgd;
for (i = 0; i < USER_PTRS_PER_PGD; i++) {
pmdval = (i << PGDIR_SHIFT);
p4d = p4d_offset(pgd, i << PGDIR_SHIFT);
pud = pud_offset(p4d, i << PGDIR_SHIFT);
pmd = pmd_offset(pud + i, i << PGDIR_SHIFT);
set_pmd(pmd, __pmd(pmdval));
}
}
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