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Linux kernel mirror (for testing)
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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * PGD allocation/freeing
4 *
5 * Copyright (C) 2012 ARM Ltd.
6 * Author: Catalin Marinas <catalin.marinas@arm.com>
7 */
8
9#include <linux/mm.h>
10#include <linux/gfp.h>
11#include <linux/highmem.h>
12#include <linux/slab.h>
13
14#include <asm/pgalloc.h>
15#include <asm/page.h>
16#include <asm/tlbflush.h>
17
18static struct kmem_cache *pgd_cache __ro_after_init;
19
20pgd_t *pgd_alloc(struct mm_struct *mm)
21{
22 gfp_t gfp = GFP_PGTABLE_USER;
23
24 if (PGD_SIZE == PAGE_SIZE)
25 return (pgd_t *)__get_free_page(gfp);
26 else
27 return kmem_cache_alloc(pgd_cache, gfp);
28}
29
30void pgd_free(struct mm_struct *mm, pgd_t *pgd)
31{
32 if (PGD_SIZE == PAGE_SIZE)
33 free_page((unsigned long)pgd);
34 else
35 kmem_cache_free(pgd_cache, pgd);
36}
37
38void __init pgtable_cache_init(void)
39{
40 if (PGD_SIZE == PAGE_SIZE)
41 return;
42
43#ifdef CONFIG_ARM64_PA_BITS_52
44 /*
45 * With 52-bit physical addresses, the architecture requires the
46 * top-level table to be aligned to at least 64 bytes.
47 */
48 BUILD_BUG_ON(PGD_SIZE < 64);
49#endif
50
51 /*
52 * Naturally aligned pgds required by the architecture.
53 */
54 pgd_cache = kmem_cache_create("pgd_cache", PGD_SIZE, PGD_SIZE,
55 SLAB_PANIC, NULL);
56}