1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2002 Richard Henderson
4 * Copyright (C) 2001 Rusty Russell, 2002, 2010 Rusty Russell IBM.
5 * Copyright (C) 2023 Luis Chamberlain <mcgrof@kernel.org>
6 * Copyright (C) 2024 Mike Rapoport IBM.
7 */
8
9 #include <linux/mm.h>
10 #include <linux/vmalloc.h>
11 #include <linux/execmem.h>
12 #include <linux/moduleloader.h>
13
14 static struct execmem_info *execmem_info __ro_after_init;
15 static struct execmem_info default_execmem_info __ro_after_init;
16
17 static void *__execmem_alloc(struct execmem_range *range, size_t size)
18 {
19 bool kasan = range->flags & EXECMEM_KASAN_SHADOW;
20 unsigned long vm_flags = VM_FLUSH_RESET_PERMS;
21 gfp_t gfp_flags = GFP_KERNEL | __GFP_NOWARN;
22 unsigned long start = range->start;
23 unsigned long end = range->end;
24 unsigned int align = range->alignment;
25 pgprot_t pgprot = range->pgprot;
26 void *p;
27
28 if (kasan)
29 vm_flags |= VM_DEFER_KMEMLEAK;
30
31 p = __vmalloc_node_range(size, align, start, end, gfp_flags,
32 pgprot, vm_flags, NUMA_NO_NODE,
33 __builtin_return_address(0));
34 if (!p && range->fallback_start) {
35 start = range->fallback_start;
36 end = range->fallback_end;
37 p = __vmalloc_node_range(size, align, start, end, gfp_flags,
38 pgprot, vm_flags, NUMA_NO_NODE,
39 __builtin_return_address(0));
40 }
41
42 if (!p) {
43 pr_warn_ratelimited("execmem: unable to allocate memory\n");
44 return NULL;
45 }
46
47 if (kasan && (kasan_alloc_module_shadow(p, size, GFP_KERNEL) < 0)) {
48 vfree(p);
49 return NULL;
50 }
51
52 return kasan_reset_tag(p);
53 }
54
55 void *execmem_alloc(enum execmem_type type, size_t size)
56 {
57 struct execmem_range *range = &execmem_info->ranges[type];
58
59 return __execmem_alloc(range, size);
60 }
61
62 void execmem_free(void *ptr)
63 {
64 /*
65 * This memory may be RO, and freeing RO memory in an interrupt is not
66 * supported by vmalloc.
67 */
68 WARN_ON(in_interrupt());
69 vfree(ptr);
70 }
71
72 static bool execmem_validate(struct execmem_info *info)
73 {
74 struct execmem_range *r = &info->ranges[EXECMEM_DEFAULT];
75
76 if (!r->alignment || !r->start || !r->end || !pgprot_val(r->pgprot)) {
77 pr_crit("Invalid parameters for execmem allocator, module loading will fail");
78 return false;
79 }
80
81 return true;
82 }
83
84 static void execmem_init_missing(struct execmem_info *info)
85 {
86 struct execmem_range *default_range = &info->ranges[EXECMEM_DEFAULT];
87
88 for (int i = EXECMEM_DEFAULT + 1; i < EXECMEM_TYPE_MAX; i++) {
89 struct execmem_range *r = &info->ranges[i];
90
91 if (!r->start) {
92 if (i == EXECMEM_MODULE_DATA)
93 r->pgprot = PAGE_KERNEL;
94 else
95 r->pgprot = default_range->pgprot;
96 r->alignment = default_range->alignment;
97 r->start = default_range->start;
98 r->end = default_range->end;
99 r->flags = default_range->flags;
100 r->fallback_start = default_range->fallback_start;
101 r->fallback_end = default_range->fallback_end;
102 }
103 }
104 }
105
106 struct execmem_info * __weak execmem_arch_setup(void)
107 {
108 return NULL;
109 }
110
111 static void __init __execmem_init(void)
112 {
113 struct execmem_info *info = execmem_arch_setup();
114
115 if (!info) {
116 info = execmem_info = &default_execmem_info;
117 info->ranges[EXECMEM_DEFAULT].start = VMALLOC_START;
118 info->ranges[EXECMEM_DEFAULT].end = VMALLOC_END;
119 info->ranges[EXECMEM_DEFAULT].pgprot = PAGE_KERNEL_EXEC;
120 info->ranges[EXECMEM_DEFAULT].alignment = 1;
121 }
122
123 if (!execmem_validate(info))
124 return;
125
126 execmem_init_missing(info);
127
128 execmem_info = info;
129 }
130
131 #ifdef CONFIG_ARCH_WANTS_EXECMEM_LATE
132 static int __init execmem_late_init(void)
133 {
134 __execmem_init();
135 return 0;
136 }
137 core_initcall(execmem_late_init);
138 #else
139 void __init execmem_init(void)
140 {
141 __execmem_init();
142 }
143 #endif
144
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.