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