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
parse_nosmep(char * p)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
parse_nosmap(char * p)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
setup_kup(void)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
ctor(int shift)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 */
pgtable_cache_add(unsigned int shift)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 = NULL;
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 if (name)
121 new = kmem_cache_create(name, table_size, align, 0, ctor(shift));
122 if (!new)
123 panic("Could not allocate pgtable cache for order %d", shift);
124
125 kfree(name);
126 pgtable_cache[shift] = new;
127
128 pr_debug("Allocated pgtable cache for order %d\n", shift);
129 }
130 EXPORT_SYMBOL_GPL(pgtable_cache_add); /* used by kvm_hv module */
131
pgtable_cache_init(void)132 void pgtable_cache_init(void)
133 {
134 pgtable_cache_add(PGD_INDEX_SIZE);
135
136 if (PMD_CACHE_INDEX)
137 pgtable_cache_add(PMD_CACHE_INDEX);
138 /*
139 * In all current configs, when the PUD index exists it's the
140 * same size as either the pgd or pmd index except with THP enabled
141 * on book3s 64
142 */
143 if (PUD_CACHE_INDEX)
144 pgtable_cache_add(PUD_CACHE_INDEX);
145 }
146