/arch/unicore32/mm/pgd.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * linux/arch/unicore32/mm/pgd.c
  4 *
  5 * Code specific to PKUnity SoC and UniCore ISA
  6 *
  7 * Copyright (C) 2001-2010 GUAN Xue-tao
  8 */
  9#include <linux/mm.h>
 10#include <linux/gfp.h>
 11#include <linux/highmem.h>
 12
 13#include <asm/pgalloc.h>
 14#include <asm/page.h>
 15#include <asm/tlbflush.h>
 16
 17#include "mm.h"
 18
 19#define FIRST_KERNEL_PGD_NR	(FIRST_USER_PGD_NR + USER_PTRS_PER_PGD)
 20
 21/*
 22 * need to get a 4k page for level 1
 23 */
 24pgd_t *get_pgd_slow(struct mm_struct *mm)
 25{
 26	pgd_t *new_pgd, *init_pgd;
 27	pmd_t *new_pmd, *init_pmd;
 28	pte_t *new_pte, *init_pte;
 29
 30	new_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, 0);
 31	if (!new_pgd)
 32		goto no_pgd;
 33
 34	memset(new_pgd, 0, FIRST_KERNEL_PGD_NR * sizeof(pgd_t));
 35
 36	/*
 37	 * Copy over the kernel and IO PGD entries
 38	 */
 39	init_pgd = pgd_offset_k(0);
 40	memcpy(new_pgd + FIRST_KERNEL_PGD_NR, init_pgd + FIRST_KERNEL_PGD_NR,
 41		       (PTRS_PER_PGD - FIRST_KERNEL_PGD_NR) * sizeof(pgd_t));
 42
 43	clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t));
 44
 45	if (!vectors_high()) {
 46		/*
 47		 * On UniCore, first page must always be allocated since it
 48		 * contains the machine vectors.
 49		 */
 50		new_pmd = pmd_alloc(mm, (pud_t *)new_pgd, 0);
 51		if (!new_pmd)
 52			goto no_pmd;
 53
 54		new_pte = pte_alloc_map(mm, new_pmd, 0);
 55		if (!new_pte)
 56			goto no_pte;
 57
 58		init_pmd = pmd_offset((pud_t *)init_pgd, 0);
 59		init_pte = pte_offset_map(init_pmd, 0);
 60		set_pte(new_pte, *init_pte);
 61		pte_unmap(init_pte);
 62		pte_unmap(new_pte);
 63	}
 64
 65	return new_pgd;
 66
 67no_pte:
 68	pmd_free(mm, new_pmd);
 69	mm_dec_nr_pmds(mm);
 70no_pmd:
 71	free_pages((unsigned long)new_pgd, 0);
 72no_pgd:
 73	return NULL;
 74}
 75
 76void free_pgd_slow(struct mm_struct *mm, pgd_t *pgd)
 77{
 78	pmd_t *pmd;
 79	pgtable_t pte;
 80
 81	if (!pgd)
 82		return;
 83
 84	/* pgd is always present and good */
 85	pmd = pmd_off(pgd, 0);
 86	if (pmd_none(*pmd))
 87		goto free;
 88	if (pmd_bad(*pmd)) {
 89		pmd_ERROR(*pmd);
 90		pmd_clear(pmd);
 91		goto free;
 92	}
 93
 94	pte = pmd_pgtable(*pmd);
 95	pmd_clear(pmd);
 96	pte_free(mm, pte);
 97	mm_dec_nr_ptes(mm);
 98	pmd_free(mm, pmd);
 99	mm_dec_nr_pmds(mm);
100free:
101	free_pages((unsigned long) pgd, 0);
102}