1 /* 2 * PowerPC version 3 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) 4 * 5 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au) 6 * and Cort Dougan (PReP) (cort@cs.nmt.edu) 7 * Copyright (C) 1996 Paul Mackerras 8 * 9 * Derived from "arch/i386/mm/init.c" 10 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds 11 * 12 * Dave Engebretsen <engebret@us.ibm.com> 13 * Rework for PPC64 port. 14 * 15 * This program is free software; you can redistribute it and/or 16 * modify it under the terms of the GNU General Public License 17 * as published by the Free Software Foundation; either version 18 * 2 of the License, or (at your option) any later version. 19 * 20 */ 21 22 #undef DEBUG 23 24 #include <linux/string.h> 25 #include <asm/pgalloc.h> 26 #include <asm/pgtable.h> 27 28 static void pgd_ctor(void *addr) 29 { 30 memset(addr, 0, PGD_TABLE_SIZE); 31 } 32 33 static void pud_ctor(void *addr) 34 { 35 memset(addr, 0, PUD_TABLE_SIZE); 36 } 37 38 static void pmd_ctor(void *addr) 39 { 40 memset(addr, 0, PMD_TABLE_SIZE); 41 } 42 43 struct kmem_cache *pgtable_cache[MAX_PGTABLE_INDEX_SIZE]; 44 EXPORT_SYMBOL_GPL(pgtable_cache); /* used by kvm_hv module */ 45 46 /* 47 * Create a kmem_cache() for pagetables. This is not used for PTE 48 * pages - they're linked to struct page, come from the normal free 49 * pages pool and have a different entry size (see real_pte_t) to 50 * everything else. Caches created by this function are used for all 51 * the higher level pagetables, and for hugepage pagetables. 52 */ 53 void pgtable_cache_add(unsigned shift, void (*ctor)(void *)) 54 { 55 char *name; 56 unsigned long table_size = sizeof(void *) << shift; 57 unsigned long align = table_size; 58 59 /* When batching pgtable pointers for RCU freeing, we store 60 * the index size in the low bits. Table alignment must be 61 * big enough to fit it. 62 * 63 * Likewise, hugeapge pagetable pointers contain a (different) 64 * shift value in the low bits. All tables must be aligned so 65 * as to leave enough 0 bits in the address to contain it. */ 66 unsigned long minalign = max(MAX_PGTABLE_INDEX_SIZE + 1, 67 HUGEPD_SHIFT_MASK + 1); 68 struct kmem_cache *new; 69 70 /* It would be nice if this was a BUILD_BUG_ON(), but at the 71 * moment, gcc doesn't seem to recognize is_power_of_2 as a 72 * constant expression, so so much for that. */ 73 BUG_ON(!is_power_of_2(minalign)); 74 BUG_ON((shift < 1) || (shift > MAX_PGTABLE_INDEX_SIZE)); 75 76 if (PGT_CACHE(shift)) 77 return; /* Already have a cache of this size */ 78 79 align = max_t(unsigned long, align, minalign); 80 name = kasprintf(GFP_KERNEL, "pgtable-2^%d", shift); 81 new = kmem_cache_create(name, table_size, align, 0, ctor); 82 if (!new) 83 panic("Could not allocate pgtable cache for order %d", shift); 84 85 kfree(name); 86 pgtable_cache[shift - 1] = new; 87 88 pr_debug("Allocated pgtable cache for order %d\n", shift); 89 } 90 EXPORT_SYMBOL_GPL(pgtable_cache_add); /* used by kvm_hv module */ 91 92 void pgtable_cache_init(void) 93 { 94 pgtable_cache_add(PGD_INDEX_SIZE, pgd_ctor); 95 96 if (PMD_CACHE_INDEX && !PGT_CACHE(PMD_CACHE_INDEX)) 97 pgtable_cache_add(PMD_CACHE_INDEX, pmd_ctor); 98 /* 99 * In all current configs, when the PUD index exists it's the 100 * same size as either the pgd or pmd index except with THP enabled 101 * on book3s 64 102 */ 103 if (PUD_CACHE_INDEX && !PGT_CACHE(PUD_CACHE_INDEX)) 104 pgtable_cache_add(PUD_CACHE_INDEX, pud_ctor); 105 } 106