1 /* SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2014-2017 Linaro Ltd. <ard.biesheuvel@linaro.org>
5 * Copyright (C) 2018 Andes Technology Corporation <zong@andestech.com>
9 #include <linux/kernel.h>
10 #include <linux/module.h>
12 unsigned long module_emit_got_entry(struct module *mod, unsigned long val)
14 struct mod_section *got_sec = &mod->arch.got;
15 int i = got_sec->num_entries;
16 struct got_entry *got = get_got_entry(val, got_sec);
19 return (unsigned long)got;
21 /* There is no duplicate entry, create a new one */
22 got = (struct got_entry *)got_sec->shdr->sh_addr;
23 got[i] = emit_got_entry(val);
25 got_sec->num_entries++;
26 BUG_ON(got_sec->num_entries > got_sec->max_entries);
28 return (unsigned long)&got[i];
31 unsigned long module_emit_plt_entry(struct module *mod, unsigned long val)
33 struct mod_section *got_plt_sec = &mod->arch.got_plt;
34 struct got_entry *got_plt;
35 struct mod_section *plt_sec = &mod->arch.plt;
36 struct plt_entry *plt = get_plt_entry(val, plt_sec, got_plt_sec);
37 int i = plt_sec->num_entries;
40 return (unsigned long)plt;
42 /* There is no duplicate entry, create a new one */
43 got_plt = (struct got_entry *)got_plt_sec->shdr->sh_addr;
44 got_plt[i] = emit_got_entry(val);
45 plt = (struct plt_entry *)plt_sec->shdr->sh_addr;
46 plt[i] = emit_plt_entry(val,
47 (unsigned long)&plt[i],
48 (unsigned long)&got_plt[i]);
50 plt_sec->num_entries++;
51 got_plt_sec->num_entries++;
52 BUG_ON(plt_sec->num_entries > plt_sec->max_entries);
54 return (unsigned long)&plt[i];
57 static int is_rela_equal(const Elf_Rela *x, const Elf_Rela *y)
59 return x->r_info == y->r_info && x->r_addend == y->r_addend;
62 static bool duplicate_rela(const Elf_Rela *rela, int idx)
65 for (i = 0; i < idx; i++) {
66 if (is_rela_equal(&rela[i], &rela[idx]))
72 static void count_max_entries(Elf_Rela *relas, int num,
73 unsigned int *plts, unsigned int *gots)
77 for (i = 0; i < num; i++) {
78 type = ELF_RISCV_R_TYPE(relas[i].r_info);
79 if (type == R_RISCV_CALL_PLT) {
80 if (!duplicate_rela(relas, i))
82 } else if (type == R_RISCV_GOT_HI20) {
83 if (!duplicate_rela(relas, i))
89 int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
90 char *secstrings, struct module *mod)
92 unsigned int num_plts = 0;
93 unsigned int num_gots = 0;
97 * Find the empty .got and .plt sections.
99 for (i = 0; i < ehdr->e_shnum; i++) {
100 if (!strcmp(secstrings + sechdrs[i].sh_name, ".plt"))
101 mod->arch.plt.shdr = sechdrs + i;
102 else if (!strcmp(secstrings + sechdrs[i].sh_name, ".got"))
103 mod->arch.got.shdr = sechdrs + i;
104 else if (!strcmp(secstrings + sechdrs[i].sh_name, ".got.plt"))
105 mod->arch.got_plt.shdr = sechdrs + i;
108 if (!mod->arch.plt.shdr) {
109 pr_err("%s: module PLT section(s) missing\n", mod->name);
112 if (!mod->arch.got.shdr) {
113 pr_err("%s: module GOT section(s) missing\n", mod->name);
116 if (!mod->arch.got_plt.shdr) {
117 pr_err("%s: module GOT.PLT section(s) missing\n", mod->name);
121 /* Calculate the maxinum number of entries */
122 for (i = 0; i < ehdr->e_shnum; i++) {
123 Elf_Rela *relas = (void *)ehdr + sechdrs[i].sh_offset;
124 int num_rela = sechdrs[i].sh_size / sizeof(Elf_Rela);
125 Elf_Shdr *dst_sec = sechdrs + sechdrs[i].sh_info;
127 if (sechdrs[i].sh_type != SHT_RELA)
130 /* ignore relocations that operate on non-exec sections */
131 if (!(dst_sec->sh_flags & SHF_EXECINSTR))
134 count_max_entries(relas, num_rela, &num_plts, &num_gots);
137 mod->arch.plt.shdr->sh_type = SHT_NOBITS;
138 mod->arch.plt.shdr->sh_flags = SHF_EXECINSTR | SHF_ALLOC;
139 mod->arch.plt.shdr->sh_addralign = L1_CACHE_BYTES;
140 mod->arch.plt.shdr->sh_size = (num_plts + 1) * sizeof(struct plt_entry);
141 mod->arch.plt.num_entries = 0;
142 mod->arch.plt.max_entries = num_plts;
144 mod->arch.got.shdr->sh_type = SHT_NOBITS;
145 mod->arch.got.shdr->sh_flags = SHF_ALLOC;
146 mod->arch.got.shdr->sh_addralign = L1_CACHE_BYTES;
147 mod->arch.got.shdr->sh_size = (num_gots + 1) * sizeof(struct got_entry);
148 mod->arch.got.num_entries = 0;
149 mod->arch.got.max_entries = num_gots;
151 mod->arch.got_plt.shdr->sh_type = SHT_NOBITS;
152 mod->arch.got_plt.shdr->sh_flags = SHF_ALLOC;
153 mod->arch.got_plt.shdr->sh_addralign = L1_CACHE_BYTES;
154 mod->arch.got_plt.shdr->sh_size = (num_plts + 1) * sizeof(struct got_entry);
155 mod->arch.got_plt.num_entries = 0;
156 mod->arch.got_plt.max_entries = num_plts;