tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
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}