122 lines
3.2 KiB
C
122 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
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*/
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#include <linux/elf.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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Elf_Addr module_emit_plt_entry(struct module *mod, unsigned long val)
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{
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int nr;
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struct mod_section *plt_sec = &mod->arch.plt;
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struct mod_section *plt_idx_sec = &mod->arch.plt_idx;
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struct plt_entry *plt = get_plt_entry(val, plt_sec, plt_idx_sec);
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struct plt_idx_entry *plt_idx;
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if (plt)
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return (Elf_Addr)plt;
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nr = plt_sec->num_entries;
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/* There is no duplicate entry, create a new one */
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plt = (struct plt_entry *)plt_sec->shdr->sh_addr;
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plt[nr] = emit_plt_entry(val);
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plt_idx = (struct plt_idx_entry *)plt_idx_sec->shdr->sh_addr;
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plt_idx[nr] = emit_plt_idx_entry(val);
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plt_sec->num_entries++;
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plt_idx_sec->num_entries++;
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BUG_ON(plt_sec->num_entries > plt_sec->max_entries);
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return (Elf_Addr)&plt[nr];
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}
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static int is_rela_equal(const Elf_Rela *x, const Elf_Rela *y)
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{
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return x->r_info == y->r_info && x->r_addend == y->r_addend;
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}
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static bool duplicate_rela(const Elf_Rela *rela, int idx)
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{
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int i;
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for (i = 0; i < idx; i++) {
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if (is_rela_equal(&rela[i], &rela[idx]))
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return true;
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}
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return false;
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}
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static void count_max_entries(Elf_Rela *relas, int num, unsigned int *plts)
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{
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unsigned int i, type;
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for (i = 0; i < num; i++) {
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type = ELF_R_TYPE(relas[i].r_info);
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if (type == R_LARCH_SOP_PUSH_PLT_PCREL) {
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if (!duplicate_rela(relas, i))
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(*plts)++;
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}
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}
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}
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int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
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char *secstrings, struct module *mod)
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{
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unsigned int i, num_plts = 0;
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/*
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* Find the empty .plt sections.
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*/
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for (i = 0; i < ehdr->e_shnum; i++) {
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if (!strcmp(secstrings + sechdrs[i].sh_name, ".plt"))
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mod->arch.plt.shdr = sechdrs + i;
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else if (!strcmp(secstrings + sechdrs[i].sh_name, ".plt.idx"))
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mod->arch.plt_idx.shdr = sechdrs + i;
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}
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if (!mod->arch.plt.shdr) {
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pr_err("%s: module PLT section(s) missing\n", mod->name);
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return -ENOEXEC;
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}
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if (!mod->arch.plt_idx.shdr) {
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pr_err("%s: module PLT.IDX section(s) missing\n", mod->name);
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return -ENOEXEC;
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}
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/* Calculate the maxinum number of entries */
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for (i = 0; i < ehdr->e_shnum; i++) {
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int num_rela = sechdrs[i].sh_size / sizeof(Elf_Rela);
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Elf_Rela *relas = (void *)ehdr + sechdrs[i].sh_offset;
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Elf_Shdr *dst_sec = sechdrs + sechdrs[i].sh_info;
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if (sechdrs[i].sh_type != SHT_RELA)
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continue;
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/* ignore relocations that operate on non-exec sections */
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if (!(dst_sec->sh_flags & SHF_EXECINSTR))
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continue;
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count_max_entries(relas, num_rela, &num_plts);
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}
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mod->arch.plt.shdr->sh_type = SHT_NOBITS;
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mod->arch.plt.shdr->sh_flags = SHF_EXECINSTR | SHF_ALLOC;
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mod->arch.plt.shdr->sh_addralign = L1_CACHE_BYTES;
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mod->arch.plt.shdr->sh_size = (num_plts + 1) * sizeof(struct plt_entry);
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mod->arch.plt.num_entries = 0;
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mod->arch.plt.max_entries = num_plts;
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mod->arch.plt_idx.shdr->sh_type = SHT_NOBITS;
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mod->arch.plt_idx.shdr->sh_flags = SHF_ALLOC;
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mod->arch.plt_idx.shdr->sh_addralign = L1_CACHE_BYTES;
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mod->arch.plt_idx.shdr->sh_size = (num_plts + 1) * sizeof(struct plt_idx_entry);
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mod->arch.plt_idx.num_entries = 0;
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mod->arch.plt_idx.max_entries = num_plts;
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return 0;
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}
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