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2a0b5c0d19
When the pgd size is smaller than PAGE_SIZE, pgd_alloc() uses kzalloc() to save space. However, this is not always naturally aligned as required by the architecture. This patch creates a kmem_cache for pgd allocations with the correct alignment. The current kernel configurations with 4K pages + 39-bit VA and 64K pages + 42-bit VA use a full page for the pgd and are not affected. The patch is required for 48-bit VA with 64K pages where the pgd is 512 bytes. Reported-by: Christoffer Dall <christoffer.dall@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
61 lines
1.5 KiB
C
61 lines
1.5 KiB
C
/*
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* PGD allocation/freeing
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*
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* Copyright (C) 2012 ARM Ltd.
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* Author: Catalin Marinas <catalin.marinas@arm.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/mm.h>
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#include <linux/gfp.h>
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#include <linux/highmem.h>
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#include <linux/slab.h>
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#include <asm/pgalloc.h>
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#include <asm/page.h>
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#include <asm/tlbflush.h>
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#include "mm.h"
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#define PGD_SIZE (PTRS_PER_PGD * sizeof(pgd_t))
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static struct kmem_cache *pgd_cache;
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pgd_t *pgd_alloc(struct mm_struct *mm)
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{
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if (PGD_SIZE == PAGE_SIZE)
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return (pgd_t *)get_zeroed_page(GFP_KERNEL);
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else
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return kmem_cache_zalloc(pgd_cache, GFP_KERNEL);
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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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if (PGD_SIZE == PAGE_SIZE)
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free_page((unsigned long)pgd);
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else
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kmem_cache_free(pgd_cache, pgd);
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}
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static int __init pgd_cache_init(void)
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{
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/*
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* Naturally aligned pgds required by the architecture.
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*/
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if (PGD_SIZE != PAGE_SIZE)
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pgd_cache = kmem_cache_create("pgd_cache", PGD_SIZE, PGD_SIZE,
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SLAB_PANIC, NULL);
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return 0;
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}
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core_initcall(pgd_cache_init);
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