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