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 <linux/pgtable.h> 21 #include <asm/pgalloc.h> 22 #include <asm/kup.h> 23 #include <asm/smp.h> 24 25 phys_addr_t memstart_addr __ro_after_init = (phys_addr_t)~0ull; 26 EXPORT_SYMBOL_GPL(memstart_addr); 27 phys_addr_t kernstart_addr __ro_after_init; 28 EXPORT_SYMBOL_GPL(kernstart_addr); 29 unsigned long kernstart_virt_addr __ro_after_init = KERNELBASE; 30 EXPORT_SYMBOL_GPL(kernstart_virt_addr); 31 32 bool disable_kuep = !IS_ENABLED(CONFIG_PPC_KUEP); 33 bool disable_kuap = !IS_ENABLED(CONFIG_PPC_KUAP); 34 35 static int __init parse_nosmep(char *p) 36 { 37 if (!IS_ENABLED(CONFIG_PPC_BOOK3S_64)) 38 return 0; 39 40 disable_kuep = true; 41 pr_warn("Disabling Kernel Userspace Execution Prevention\n"); 42 return 0; 43 } 44 early_param("nosmep", parse_nosmep); 45 46 static int __init parse_nosmap(char *p) 47 { 48 disable_kuap = true; 49 pr_warn("Disabling Kernel Userspace Access Protection\n"); 50 return 0; 51 } 52 early_param("nosmap", parse_nosmap); 53 54 void __weak setup_kuep(bool disabled) 55 { 56 if (!IS_ENABLED(CONFIG_PPC_KUEP) || disabled) 57 return; 58 59 if (smp_processor_id() != boot_cpuid) 60 return; 61 62 pr_info("Activating Kernel Userspace Execution Prevention\n"); 63 } 64 65 void setup_kup(void) 66 { 67 setup_kuap(disable_kuap); 68 setup_kuep(disable_kuep); 69 } 70 71 #define CTOR(shift) static void ctor_##shift(void *addr) \ 72 { \ 73 memset(addr, 0, sizeof(void *) << (shift)); \ 74 } 75 76 CTOR(0); CTOR(1); CTOR(2); CTOR(3); CTOR(4); CTOR(5); CTOR(6); CTOR(7); 77 CTOR(8); CTOR(9); CTOR(10); CTOR(11); CTOR(12); CTOR(13); CTOR(14); CTOR(15); 78 79 static inline void (*ctor(int shift))(void *) 80 { 81 BUILD_BUG_ON(MAX_PGTABLE_INDEX_SIZE != 15); 82 83 switch (shift) { 84 case 0: return ctor_0; 85 case 1: return ctor_1; 86 case 2: return ctor_2; 87 case 3: return ctor_3; 88 case 4: return ctor_4; 89 case 5: return ctor_5; 90 case 6: return ctor_6; 91 case 7: return ctor_7; 92 case 8: return ctor_8; 93 case 9: return ctor_9; 94 case 10: return ctor_10; 95 case 11: return ctor_11; 96 case 12: return ctor_12; 97 case 13: return ctor_13; 98 case 14: return ctor_14; 99 case 15: return ctor_15; 100 } 101 return NULL; 102 } 103 104 struct kmem_cache *pgtable_cache[MAX_PGTABLE_INDEX_SIZE + 1]; 105 EXPORT_SYMBOL_GPL(pgtable_cache); /* used by kvm_hv module */ 106 107 /* 108 * Create a kmem_cache() for pagetables. This is not used for PTE 109 * pages - they're linked to struct page, come from the normal free 110 * pages pool and have a different entry size (see real_pte_t) to 111 * everything else. Caches created by this function are used for all 112 * the higher level pagetables, and for hugepage pagetables. 113 */ 114 void pgtable_cache_add(unsigned int shift) 115 { 116 char *name; 117 unsigned long table_size = sizeof(void *) << shift; 118 unsigned long align = table_size; 119 120 /* When batching pgtable pointers for RCU freeing, we store 121 * the index size in the low bits. Table alignment must be 122 * big enough to fit it. 123 * 124 * Likewise, hugeapge pagetable pointers contain a (different) 125 * shift value in the low bits. All tables must be aligned so 126 * as to leave enough 0 bits in the address to contain it. */ 127 unsigned long minalign = max(MAX_PGTABLE_INDEX_SIZE + 1, 128 HUGEPD_SHIFT_MASK + 1); 129 struct kmem_cache *new; 130 131 /* It would be nice if this was a BUILD_BUG_ON(), but at the 132 * moment, gcc doesn't seem to recognize is_power_of_2 as a 133 * constant expression, so so much for that. */ 134 BUG_ON(!is_power_of_2(minalign)); 135 BUG_ON(shift > MAX_PGTABLE_INDEX_SIZE); 136 137 if (PGT_CACHE(shift)) 138 return; /* Already have a cache of this size */ 139 140 align = max_t(unsigned long, align, minalign); 141 name = kasprintf(GFP_KERNEL, "pgtable-2^%d", shift); 142 new = kmem_cache_create(name, table_size, align, 0, ctor(shift)); 143 if (!new) 144 panic("Could not allocate pgtable cache for order %d", shift); 145 146 kfree(name); 147 pgtable_cache[shift] = new; 148 149 pr_debug("Allocated pgtable cache for order %d\n", shift); 150 } 151 EXPORT_SYMBOL_GPL(pgtable_cache_add); /* used by kvm_hv module */ 152 153 void pgtable_cache_init(void) 154 { 155 pgtable_cache_add(PGD_INDEX_SIZE); 156 157 if (PMD_CACHE_INDEX) 158 pgtable_cache_add(PMD_CACHE_INDEX); 159 /* 160 * In all current configs, when the PUD index exists it's the 161 * same size as either the pgd or pmd index except with THP enabled 162 * on book3s 64 163 */ 164 if (PUD_CACHE_INDEX) 165 pgtable_cache_add(PUD_CACHE_INDEX); 166 } 167