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
25phys_addr_t memstart_addr __ro_after_init = (phys_addr_t)~0ull;
26EXPORT_SYMBOL_GPL(memstart_addr);
27phys_addr_t kernstart_addr __ro_after_init;
28EXPORT_SYMBOL_GPL(kernstart_addr);
29unsigned long kernstart_virt_addr __ro_after_init = KERNELBASE;
30EXPORT_SYMBOL_GPL(kernstart_virt_addr);
31
32bool disable_kuep = !IS_ENABLED(CONFIG_PPC_KUEP);
33bool disable_kuap = !IS_ENABLED(CONFIG_PPC_KUAP);
34
35static 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}
44early_param("nosmep", parse_nosmep);
45
46static int __init parse_nosmap(char *p)
47{
48 disable_kuap = true;
49 pr_warn("Disabling Kernel Userspace Access Protection\n");
50 return 0;
51}
52early_param("nosmap", parse_nosmap);
53
54void __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
65void 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
76CTOR(0); CTOR(1); CTOR(2); CTOR(3); CTOR(4); CTOR(5); CTOR(6); CTOR(7);
77CTOR(8); CTOR(9); CTOR(10); CTOR(11); CTOR(12); CTOR(13); CTOR(14); CTOR(15);
78
79static 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
104struct kmem_cache *pgtable_cache[MAX_PGTABLE_INDEX_SIZE + 1];
105EXPORT_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 */
114void 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 = NULL;
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, fmt: "pgtable-2^%d", shift);
142 if (name)
143 new = kmem_cache_create(name, size: table_size, align, flags: 0, ctor: ctor(shift));
144 if (!new)
145 panic(fmt: "Could not allocate pgtable cache for order %d", shift);
146
147 kfree(objp: name);
148 pgtable_cache[shift] = new;
149
150 pr_debug("Allocated pgtable cache for order %d\n", shift);
151}
152EXPORT_SYMBOL_GPL(pgtable_cache_add); /* used by kvm_hv module */
153
154void pgtable_cache_init(void)
155{
156 pgtable_cache_add(PGD_INDEX_SIZE);
157
158 if (PMD_CACHE_INDEX)
159 pgtable_cache_add(PMD_CACHE_INDEX);
160 /*
161 * In all current configs, when the PUD index exists it's the
162 * same size as either the pgd or pmd index except with THP enabled
163 * on book3s 64
164 */
165 if (PUD_CACHE_INDEX)
166 pgtable_cache_add(PUD_CACHE_INDEX);
167}
168

source code of linux/arch/powerpc/mm/init-common.c