/*
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* PowerPC version
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* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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*
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* Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
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* and Cort Dougan (PReP) (cort@cs.nmt.edu)
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* Copyright (C) 1996 Paul Mackerras
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*
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* Derived from "arch/i386/mm/init.c"
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* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
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*
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* Dave Engebretsen <engebret@us.ibm.com>
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* Rework for PPC64 port.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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*/
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#undef DEBUG
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#include <linux/string.h>
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#include <asm/pgalloc.h>
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#include <asm/pgtable.h>
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static void pgd_ctor(void *addr)
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{
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memset(addr, 0, PGD_TABLE_SIZE);
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}
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static void pud_ctor(void *addr)
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{
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memset(addr, 0, PUD_TABLE_SIZE);
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}
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static void pmd_ctor(void *addr)
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{
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memset(addr, 0, PMD_TABLE_SIZE);
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}
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struct kmem_cache *pgtable_cache[MAX_PGTABLE_INDEX_SIZE];
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EXPORT_SYMBOL_GPL(pgtable_cache); /* used by kvm_hv module */
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/*
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* Create a kmem_cache() for pagetables. This is not used for PTE
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* pages - they're linked to struct page, come from the normal free
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* pages pool and have a different entry size (see real_pte_t) to
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* everything else. Caches created by this function are used for all
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* the higher level pagetables, and for hugepage pagetables.
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*/
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void pgtable_cache_add(unsigned shift, void (*ctor)(void *))
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{
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char *name;
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unsigned long table_size = sizeof(void *) << shift;
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unsigned long align = table_size;
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/* When batching pgtable pointers for RCU freeing, we store
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* the index size in the low bits. Table alignment must be
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* big enough to fit it.
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*
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* Likewise, hugeapge pagetable pointers contain a (different)
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* shift value in the low bits. All tables must be aligned so
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* as to leave enough 0 bits in the address to contain it. */
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unsigned long minalign = max(MAX_PGTABLE_INDEX_SIZE + 1,
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HUGEPD_SHIFT_MASK + 1);
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struct kmem_cache *new;
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/* It would be nice if this was a BUILD_BUG_ON(), but at the
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* moment, gcc doesn't seem to recognize is_power_of_2 as a
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* constant expression, so so much for that. */
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BUG_ON(!is_power_of_2(minalign));
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BUG_ON((shift < 1) || (shift > MAX_PGTABLE_INDEX_SIZE));
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if (PGT_CACHE(shift))
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return; /* Already have a cache of this size */
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align = max_t(unsigned long, align, minalign);
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name = kasprintf(GFP_KERNEL, "pgtable-2^%d", shift);
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new = kmem_cache_create(name, table_size, align, 0, ctor);
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if (!new)
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panic("Could not allocate pgtable cache for order %d", shift);
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kfree(name);
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pgtable_cache[shift - 1] = new;
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pr_debug("Allocated pgtable cache for order %d\n", shift);
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}
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EXPORT_SYMBOL_GPL(pgtable_cache_add); /* used by kvm_hv module */
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void pgtable_cache_init(void)
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{
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pgtable_cache_add(PGD_INDEX_SIZE, pgd_ctor);
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if (PMD_CACHE_INDEX && !PGT_CACHE(PMD_CACHE_INDEX))
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pgtable_cache_add(PMD_CACHE_INDEX, pmd_ctor);
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/*
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* In all current configs, when the PUD index exists it's the
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* same size as either the pgd or pmd index except with THP enabled
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* on book3s 64
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*/
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if (PUD_CACHE_INDEX && !PGT_CACHE(PUD_CACHE_INDEX))
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pgtable_cache_add(PUD_CACHE_INDEX, pud_ctor);
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}
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