| 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 | |
| 18 | static struct kmem_cache *pgd_cache __ro_after_init; |
| 19 | |
| 20 | static bool pgdir_is_page_size(void) |
| 21 | { |
| 22 | if (PGD_SIZE == PAGE_SIZE) |
| 23 | return true; |
| 24 | if (CONFIG_PGTABLE_LEVELS == 4) |
| 25 | return !pgtable_l4_enabled(); |
| 26 | if (CONFIG_PGTABLE_LEVELS == 5) |
| 27 | return !pgtable_l5_enabled(); |
| 28 | return false; |
| 29 | } |
| 30 | |
| 31 | pgd_t *pgd_alloc(struct mm_struct *mm) |
| 32 | { |
| 33 | gfp_t gfp = GFP_PGTABLE_USER; |
| 34 | |
| 35 | if (pgdir_is_page_size()) |
| 36 | return (pgd_t *)__get_free_page(gfp); |
| 37 | else |
| 38 | return kmem_cache_alloc(cachep: pgd_cache, flags: gfp); |
| 39 | } |
| 40 | |
| 41 | void pgd_free(struct mm_struct *mm, pgd_t *pgd) |
| 42 | { |
| 43 | if (pgdir_is_page_size()) |
| 44 | free_page((unsigned long)pgd); |
| 45 | else |
| 46 | kmem_cache_free(s: pgd_cache, objp: pgd); |
| 47 | } |
| 48 | |
| 49 | void __init pgtable_cache_init(void) |
| 50 | { |
| 51 | if (pgdir_is_page_size()) |
| 52 | return; |
| 53 | |
| 54 | #ifdef CONFIG_ARM64_PA_BITS_52 |
| 55 | /* |
| 56 | * With 52-bit physical addresses, the architecture requires the |
| 57 | * top-level table to be aligned to at least 64 bytes. |
| 58 | */ |
| 59 | BUILD_BUG_ON(PGD_SIZE < 64); |
| 60 | #endif |
| 61 | |
| 62 | /* |
| 63 | * Naturally aligned pgds required by the architecture. |
| 64 | */ |
| 65 | pgd_cache = kmem_cache_create(name: "pgd_cache", size: PGD_SIZE, align: PGD_SIZE, |
| 66 | SLAB_PANIC, NULL); |
| 67 | } |
| 68 |