forked from Minki/linux
arm64: mm: move pgd_cache initialisation to pgtable_cache_init
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>
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@ -676,7 +676,8 @@ extern int kern_addr_valid(unsigned long addr);
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#include <asm-generic/pgtable.h>
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#define pgtable_cache_init() do { } while (0)
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void pgd_cache_init(void);
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#define pgtable_cache_init pgd_cache_init
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/*
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* On AArch64, the cache coherency is handled via the set_pte_at() function.
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@ -46,14 +46,14 @@ void pgd_free(struct mm_struct *mm, pgd_t *pgd)
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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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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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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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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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core_initcall(pgd_cache_init);
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