1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * PowerPC version 4 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) 5 * 6 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au) 7 * and Cort Dougan (PReP) (cort@cs.nmt.edu) 8 * Copyright (C) 1996 Paul Mackerras 9 * 10 * Derived from "arch/i386/mm/init.c" 11 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds 12 * 13 * Dave Engebretsen <engebret@us.ibm.com> 14 * Rework for PPC64 port. 15 */ 16 17 #undef DEBUG 18 19 #include <linux/string.h> 20 #include <asm/pgalloc.h> 21 #include <asm/pgtable.h> 22 #include <asm/kup.h> 23 24 static bool disable_kuep = !IS_ENABLED(CONFIG_PPC_KUEP); 25 static bool disable_kuap = !IS_ENABLED(CONFIG_PPC_KUAP); 26 27 static int __init parse_nosmep(char *p) 28 { 29 disable_kuep = true; 30 pr_warn("Disabling Kernel Userspace Execution Prevention\n"); 31 return 0; 32 } 33 early_param("nosmep", parse_nosmep); 34 35 static int __init parse_nosmap(char *p) 36 { 37 disable_kuap = true; 38 pr_warn("Disabling Kernel Userspace Access Protection\n"); 39 return 0; 40 } 41 early_param("nosmap", parse_nosmap); 42 43 void __ref setup_kup(void) 44 { 45 setup_kuep(disable_kuep); 46 setup_kuap(disable_kuap); 47 } 48 49 #define CTOR(shift) static void ctor_##shift(void *addr) \ 50 { \ 51 memset(addr, 0, sizeof(void *) << (shift)); \ 52 } 53 54 CTOR(0); CTOR(1); CTOR(2); CTOR(3); CTOR(4); CTOR(5); CTOR(6); CTOR(7); 55 CTOR(8); CTOR(9); CTOR(10); CTOR(11); CTOR(12); CTOR(13); CTOR(14); CTOR(15); 56 57 static inline void (*ctor(int shift))(void *) 58 { 59 BUILD_BUG_ON(MAX_PGTABLE_INDEX_SIZE != 15); 60 61 switch (shift) { 62 case 0: return ctor_0; 63 case 1: return ctor_1; 64 case 2: return ctor_2; 65 case 3: return ctor_3; 66 case 4: return ctor_4; 67 case 5: return ctor_5; 68 case 6: return ctor_6; 69 case 7: return ctor_7; 70 case 8: return ctor_8; 71 case 9: return ctor_9; 72 case 10: return ctor_10; 73 case 11: return ctor_11; 74 case 12: return ctor_12; 75 case 13: return ctor_13; 76 case 14: return ctor_14; 77 case 15: return ctor_15; 78 } 79 return NULL; 80 } 81 82 struct kmem_cache *pgtable_cache[MAX_PGTABLE_INDEX_SIZE + 1]; 83 EXPORT_SYMBOL_GPL(pgtable_cache); /* used by kvm_hv module */ 84 85 /* 86 * Create a kmem_cache() for pagetables. This is not used for PTE 87 * pages - they're linked to struct page, come from the normal free 88 * pages pool and have a different entry size (see real_pte_t) to 89 * everything else. Caches created by this function are used for all 90 * the higher level pagetables, and for hugepage pagetables. 91 */ 92 void pgtable_cache_add(unsigned int shift) 93 { 94 char *name; 95 unsigned long table_size = sizeof(void *) << shift; 96 unsigned long align = table_size; 97 98 /* When batching pgtable pointers for RCU freeing, we store 99 * the index size in the low bits. Table alignment must be 100 * big enough to fit it. 101 * 102 * Likewise, hugeapge pagetable pointers contain a (different) 103 * shift value in the low bits. All tables must be aligned so 104 * as to leave enough 0 bits in the address to contain it. */ 105 unsigned long minalign = max(MAX_PGTABLE_INDEX_SIZE + 1, 106 HUGEPD_SHIFT_MASK + 1); 107 struct kmem_cache *new; 108 109 /* It would be nice if this was a BUILD_BUG_ON(), but at the 110 * moment, gcc doesn't seem to recognize is_power_of_2 as a 111 * constant expression, so so much for that. */ 112 BUG_ON(!is_power_of_2(minalign)); 113 BUG_ON(shift > MAX_PGTABLE_INDEX_SIZE); 114 115 if (PGT_CACHE(shift)) 116 return; /* Already have a cache of this size */ 117 118 align = max_t(unsigned long, align, minalign); 119 name = kasprintf(GFP_KERNEL, "pgtable-2^%d", shift); 120 new = kmem_cache_create(name, table_size, align, 0, ctor(shift)); 121 if (!new) 122 panic("Could not allocate pgtable cache for order %d", shift); 123 124 kfree(name); 125 pgtable_cache[shift] = new; 126 127 pr_debug("Allocated pgtable cache for order %d\n", shift); 128 } 129 EXPORT_SYMBOL_GPL(pgtable_cache_add); /* used by kvm_hv module */ 130 131 void pgtable_cache_init(void) 132 { 133 pgtable_cache_add(PGD_INDEX_SIZE); 134 135 if (PMD_CACHE_INDEX) 136 pgtable_cache_add(PMD_CACHE_INDEX); 137 /* 138 * In all current configs, when the PUD index exists it's the 139 * same size as either the pgd or pmd index except with THP enabled 140 * on book3s 64 141 */ 142 if (PUD_CACHE_INDEX) 143 pgtable_cache_add(PUD_CACHE_INDEX); 144 } 145