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39b5be9b42
Initialising the suppport for EFI runtime services requires us to allocate a pgd off the back of an early_initcall. On systems where the PGD_SIZE is smaller than PAGE_SIZE (e.g. 64k pages and 48-bit VA), the pgd_cache isn't initialised at this stage, and we panic with a NULL dereference during boot: Unable to handle kernel NULL pointer dereference at virtual address 00000000 __create_mapping.isra.5+0x84/0x350 create_pgd_mapping+0x20/0x28 efi_create_mapping+0x5c/0x6c arm_enable_runtime_services+0x154/0x1e4 do_one_initcall+0x8c/0x190 kernel_init_freeable+0x84/0x1ec kernel_init+0x10/0xe0 ret_from_fork+0x10/0x50 This patch fixes the problem by initialising the pgd_cache earlier, in the pgtable_cache_init callback, which sounds suspiciously like what it was intended for. Reported-by: Dennis Chen <dennis.chen@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
60 lines
1.5 KiB
C
60 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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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_free_page(PGALLOC_GFP);
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else
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return kmem_cache_alloc(pgd_cache, PGALLOC_GFP);
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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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void __init pgd_cache_init(void)
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{
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if (PGD_SIZE == PAGE_SIZE)
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return;
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/*
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* Naturally aligned pgds required by the architecture.
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*/
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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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}
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