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fcdfe9d2 HC |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Copyright (C) 2020-2022 Loongson Technology Corporation Limited | |
4 | */ | |
5 | ||
6 | #include <linux/elf.h> | |
7 | #include <linux/kernel.h> | |
8 | #include <linux/module.h> | |
c718a0ba | 9 | #include <linux/moduleloader.h> |
28ac0a9e | 10 | #include <linux/ftrace.h> |
fcdfe9d2 | 11 | |
9151dde4 | 12 | Elf_Addr module_emit_got_entry(struct module *mod, Elf_Shdr *sechdrs, Elf_Addr val) |
59b3d4a9 XR |
13 | { |
14 | struct mod_section *got_sec = &mod->arch.got; | |
15 | int i = got_sec->num_entries; | |
9151dde4 | 16 | struct got_entry *got = get_got_entry(val, sechdrs, got_sec); |
59b3d4a9 XR |
17 | |
18 | if (got) | |
19 | return (Elf_Addr)got; | |
20 | ||
21 | /* There is no GOT entry for val yet, create a new one. */ | |
9151dde4 | 22 | got = (struct got_entry *)sechdrs[got_sec->shndx].sh_addr; |
59b3d4a9 XR |
23 | got[i] = emit_got_entry(val); |
24 | ||
25 | got_sec->num_entries++; | |
26 | if (got_sec->num_entries > got_sec->max_entries) { | |
27 | /* | |
28 | * This may happen when the module contains a GOT_HI20 without | |
29 | * a paired GOT_LO12. Such a module is broken, reject it. | |
30 | */ | |
31 | pr_err("%s: module contains bad GOT relocation\n", mod->name); | |
32 | return 0; | |
33 | } | |
34 | ||
35 | return (Elf_Addr)&got[i]; | |
36 | } | |
37 | ||
9151dde4 | 38 | Elf_Addr module_emit_plt_entry(struct module *mod, Elf_Shdr *sechdrs, Elf_Addr val) |
fcdfe9d2 HC |
39 | { |
40 | int nr; | |
41 | struct mod_section *plt_sec = &mod->arch.plt; | |
42 | struct mod_section *plt_idx_sec = &mod->arch.plt_idx; | |
9151dde4 | 43 | struct plt_entry *plt = get_plt_entry(val, sechdrs, plt_sec, plt_idx_sec); |
fcdfe9d2 HC |
44 | struct plt_idx_entry *plt_idx; |
45 | ||
46 | if (plt) | |
47 | return (Elf_Addr)plt; | |
48 | ||
49 | nr = plt_sec->num_entries; | |
50 | ||
51 | /* There is no duplicate entry, create a new one */ | |
9151dde4 | 52 | plt = (struct plt_entry *)sechdrs[plt_sec->shndx].sh_addr; |
fcdfe9d2 | 53 | plt[nr] = emit_plt_entry(val); |
9151dde4 | 54 | plt_idx = (struct plt_idx_entry *)sechdrs[plt_idx_sec->shndx].sh_addr; |
fcdfe9d2 HC |
55 | plt_idx[nr] = emit_plt_idx_entry(val); |
56 | ||
57 | plt_sec->num_entries++; | |
58 | plt_idx_sec->num_entries++; | |
59 | BUG_ON(plt_sec->num_entries > plt_sec->max_entries); | |
60 | ||
61 | return (Elf_Addr)&plt[nr]; | |
62 | } | |
63 | ||
64 | static int is_rela_equal(const Elf_Rela *x, const Elf_Rela *y) | |
65 | { | |
66 | return x->r_info == y->r_info && x->r_addend == y->r_addend; | |
67 | } | |
68 | ||
69 | static bool duplicate_rela(const Elf_Rela *rela, int idx) | |
70 | { | |
71 | int i; | |
72 | ||
73 | for (i = 0; i < idx; i++) { | |
74 | if (is_rela_equal(&rela[i], &rela[idx])) | |
75 | return true; | |
76 | } | |
77 | ||
78 | return false; | |
79 | } | |
80 | ||
59b3d4a9 XR |
81 | static void count_max_entries(Elf_Rela *relas, int num, |
82 | unsigned int *plts, unsigned int *gots) | |
fcdfe9d2 HC |
83 | { |
84 | unsigned int i, type; | |
85 | ||
86 | for (i = 0; i < num; i++) { | |
87 | type = ELF_R_TYPE(relas[i].r_info); | |
9bd1e380 XR |
88 | switch (type) { |
89 | case R_LARCH_SOP_PUSH_PLT_PCREL: | |
90 | case R_LARCH_B26: | |
fcdfe9d2 HC |
91 | if (!duplicate_rela(relas, i)) |
92 | (*plts)++; | |
9bd1e380 | 93 | break; |
59b3d4a9 XR |
94 | case R_LARCH_GOT_PC_HI20: |
95 | if (!duplicate_rela(relas, i)) | |
96 | (*gots)++; | |
97 | break; | |
9bd1e380 XR |
98 | default: |
99 | break; /* Do nothing. */ | |
fcdfe9d2 HC |
100 | } |
101 | } | |
102 | } | |
103 | ||
104 | int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, | |
105 | char *secstrings, struct module *mod) | |
106 | { | |
59b3d4a9 | 107 | unsigned int i, num_plts = 0, num_gots = 0; |
28ac0a9e | 108 | Elf_Shdr *got_sec, *plt_sec, *plt_idx_sec, *tramp = NULL; |
fcdfe9d2 HC |
109 | |
110 | /* | |
111 | * Find the empty .plt sections. | |
112 | */ | |
113 | for (i = 0; i < ehdr->e_shnum; i++) { | |
59b3d4a9 | 114 | if (!strcmp(secstrings + sechdrs[i].sh_name, ".got")) |
9151dde4 | 115 | mod->arch.got.shndx = i; |
59b3d4a9 | 116 | else if (!strcmp(secstrings + sechdrs[i].sh_name, ".plt")) |
9151dde4 | 117 | mod->arch.plt.shndx = i; |
fcdfe9d2 | 118 | else if (!strcmp(secstrings + sechdrs[i].sh_name, ".plt.idx")) |
9151dde4 | 119 | mod->arch.plt_idx.shndx = i; |
28ac0a9e QZ |
120 | else if (!strcmp(secstrings + sechdrs[i].sh_name, ".ftrace_trampoline")) |
121 | tramp = sechdrs + i; | |
fcdfe9d2 HC |
122 | } |
123 | ||
9151dde4 | 124 | if (!mod->arch.got.shndx) { |
59b3d4a9 XR |
125 | pr_err("%s: module GOT section(s) missing\n", mod->name); |
126 | return -ENOEXEC; | |
127 | } | |
9151dde4 | 128 | if (!mod->arch.plt.shndx) { |
fcdfe9d2 HC |
129 | pr_err("%s: module PLT section(s) missing\n", mod->name); |
130 | return -ENOEXEC; | |
131 | } | |
9151dde4 | 132 | if (!mod->arch.plt_idx.shndx) { |
fcdfe9d2 HC |
133 | pr_err("%s: module PLT.IDX section(s) missing\n", mod->name); |
134 | return -ENOEXEC; | |
135 | } | |
136 | ||
137 | /* Calculate the maxinum number of entries */ | |
138 | for (i = 0; i < ehdr->e_shnum; i++) { | |
139 | int num_rela = sechdrs[i].sh_size / sizeof(Elf_Rela); | |
140 | Elf_Rela *relas = (void *)ehdr + sechdrs[i].sh_offset; | |
141 | Elf_Shdr *dst_sec = sechdrs + sechdrs[i].sh_info; | |
142 | ||
143 | if (sechdrs[i].sh_type != SHT_RELA) | |
144 | continue; | |
145 | ||
146 | /* ignore relocations that operate on non-exec sections */ | |
147 | if (!(dst_sec->sh_flags & SHF_EXECINSTR)) | |
148 | continue; | |
149 | ||
59b3d4a9 | 150 | count_max_entries(relas, num_rela, &num_plts, &num_gots); |
fcdfe9d2 HC |
151 | } |
152 | ||
9151dde4 HC |
153 | got_sec = sechdrs + mod->arch.got.shndx; |
154 | got_sec->sh_type = SHT_NOBITS; | |
155 | got_sec->sh_flags = SHF_ALLOC; | |
156 | got_sec->sh_addralign = L1_CACHE_BYTES; | |
157 | got_sec->sh_size = (num_gots + 1) * sizeof(struct got_entry); | |
59b3d4a9 XR |
158 | mod->arch.got.num_entries = 0; |
159 | mod->arch.got.max_entries = num_gots; | |
160 | ||
9151dde4 HC |
161 | plt_sec = sechdrs + mod->arch.plt.shndx; |
162 | plt_sec->sh_type = SHT_NOBITS; | |
163 | plt_sec->sh_flags = SHF_EXECINSTR | SHF_ALLOC; | |
164 | plt_sec->sh_addralign = L1_CACHE_BYTES; | |
165 | plt_sec->sh_size = (num_plts + 1) * sizeof(struct plt_entry); | |
fcdfe9d2 HC |
166 | mod->arch.plt.num_entries = 0; |
167 | mod->arch.plt.max_entries = num_plts; | |
168 | ||
9151dde4 HC |
169 | plt_idx_sec = sechdrs + mod->arch.plt_idx.shndx; |
170 | plt_idx_sec->sh_type = SHT_NOBITS; | |
171 | plt_idx_sec->sh_flags = SHF_ALLOC; | |
172 | plt_idx_sec->sh_addralign = L1_CACHE_BYTES; | |
173 | plt_idx_sec->sh_size = (num_plts + 1) * sizeof(struct plt_idx_entry); | |
fcdfe9d2 HC |
174 | mod->arch.plt_idx.num_entries = 0; |
175 | mod->arch.plt_idx.max_entries = num_plts; | |
176 | ||
28ac0a9e QZ |
177 | if (tramp) { |
178 | tramp->sh_type = SHT_NOBITS; | |
179 | tramp->sh_flags = SHF_EXECINSTR | SHF_ALLOC; | |
180 | tramp->sh_addralign = __alignof__(struct plt_entry); | |
181 | tramp->sh_size = NR_FTRACE_PLTS * sizeof(struct plt_entry); | |
182 | } | |
183 | ||
fcdfe9d2 HC |
184 | return 0; |
185 | } |