// SPDX-License-Identifier: GPL-2.0/* * Copyright (C) 2020-2022 Loongson Technology Corporation Limited */ #include <linux/elf.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/moduleloader.h>#include <linux/ftrace.h>#include <linux/sort.h> Elf_Addr module_emit_got_entry(struct module *mod, Elf_Shdr *sechdrs, Elf_Addr val){	struct mod_section *got_sec = &mod->arch.got;	int i = got_sec->num_entries;	struct got_entry *got = get_got_entry(val, sechdrs, got_sec); 	if (got)		return (Elf_Addr)got; 	/* There is no GOT entry for val yet, create a new one. */	got = (struct got_entry *)sechdrs[got_sec->shndx].sh_addr;	got[i] = emit_got_entry(val); 	got_sec->num_entries++;	if (got_sec->num_entries > got_sec->max_entries) {		/*		 * This may happen when the module contains a GOT_HI20 without		 * a paired GOT_LO12. Such a module is broken, reject it.		 */		pr_err("%s: module contains bad GOT relocation\n", mod->name);		return 0;	} 	return (Elf_Addr)&got[i];} Elf_Addr module_emit_plt_entry(struct module *mod, Elf_Shdr *sechdrs, Elf_Addr val){	int nr;	struct mod_section *plt_sec = &mod->arch.plt;	struct mod_section *plt_idx_sec = &mod->arch.plt_idx;	struct plt_entry *plt = get_plt_entry(val, sechdrs, plt_sec, plt_idx_sec);	struct plt_idx_entry *plt_idx; 	if (plt)		return (Elf_Addr)plt; 	nr = plt_sec->num_entries; 	/* There is no duplicate entry, create a new one */	plt = (struct plt_entry *)sechdrs[plt_sec->shndx].sh_addr;	plt[nr] = emit_plt_entry(val);	plt_idx = (struct plt_idx_entry *)sechdrs[plt_idx_sec->shndx].sh_addr;	plt_idx[nr] = emit_plt_idx_entry(val); 	plt_sec->num_entries++;	plt_idx_sec->num_entries++;	BUG_ON(plt_sec->num_entries > plt_sec->max_entries); 	return (Elf_Addr)&plt[nr];} static int compare_rela(const void *x, const void *y){	int ret;	const Elf_Rela *rela_x = x, *rela_y = y; 	ret = cmp_int(rela_x->r_info, rela_y->r_info);	if (ret == 0)		ret = cmp_int(rela_x->r_addend, rela_y->r_addend); 	return ret;} static void count_max_entries(Elf_Rela *relas, int num,			      unsigned int *plts, unsigned int *gots){	unsigned int i; 	sort(relas, num, sizeof(Elf_Rela), compare_rela, NULL); 	for (i = 0; i < num; i++) {		if (i && !compare_rela(&relas[i-1], &relas[i]))			continue; 		switch (ELF_R_TYPE(relas[i].r_info)) {		case R_LARCH_SOP_PUSH_PLT_PCREL:		case R_LARCH_B26:			(*plts)++;			break;		case R_LARCH_GOT_PC_HI20:		case R_LARCH_GOT_PCADD_HI20:			(*gots)++;			break;		default:			break; /* Do nothing. */		}	}} int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,			      char *secstrings, struct module *mod){	unsigned int i, num_plts = 0, num_gots = 0;	Elf_Shdr *got_sec, *plt_sec, *plt_idx_sec, *tramp = NULL; 	/*	 * Find the empty .plt sections.	 */	for (i = 0; i < ehdr->e_shnum; i++) {		if (!strcmp(secstrings + sechdrs[i].sh_name, ".got"))			mod->arch.got.shndx = i;		else if (!strcmp(secstrings + sechdrs[i].sh_name, ".plt"))			mod->arch.plt.shndx = i;		else if (!strcmp(secstrings + sechdrs[i].sh_name, ".plt.idx"))			mod->arch.plt_idx.shndx = i;		else if (!strcmp(secstrings + sechdrs[i].sh_name, ".ftrace_trampoline"))			tramp = sechdrs + i;	} 	if (!mod->arch.got.shndx) {		pr_err("%s: module GOT section(s) missing\n", mod->name);		return -ENOEXEC;	}	if (!mod->arch.plt.shndx) {		pr_err("%s: module PLT section(s) missing\n", mod->name);		return -ENOEXEC;	}	if (!mod->arch.plt_idx.shndx) {		pr_err("%s: module PLT.IDX section(s) missing\n", mod->name);		return -ENOEXEC;	} 	/* Calculate the maxinum number of entries */	for (i = 0; i < ehdr->e_shnum; i++) {		int num_rela = sechdrs[i].sh_size / sizeof(Elf_Rela);		Elf_Rela *relas = (void *)ehdr + sechdrs[i].sh_offset;		Elf_Shdr *dst_sec = sechdrs + sechdrs[i].sh_info; 		if (sechdrs[i].sh_type != SHT_RELA)			continue; 		/* ignore relocations that operate on non-exec sections */		if (!(dst_sec->sh_flags & SHF_EXECINSTR))			continue; 		count_max_entries(relas, num_rela, &num_plts, &num_gots);	} 	got_sec = sechdrs + mod->arch.got.shndx;	got_sec->sh_type = SHT_NOBITS;	got_sec->sh_flags = SHF_ALLOC;	got_sec->sh_addralign = L1_CACHE_BYTES;	got_sec->sh_size = (num_gots + 1) * sizeof(struct got_entry);	mod->arch.got.num_entries = 0;	mod->arch.got.max_entries = num_gots; 	plt_sec = sechdrs + mod->arch.plt.shndx;	plt_sec->sh_type = SHT_NOBITS;	plt_sec->sh_flags = SHF_EXECINSTR | SHF_ALLOC;	plt_sec->sh_addralign = L1_CACHE_BYTES;	plt_sec->sh_size = (num_plts + 1) * sizeof(struct plt_entry);	mod->arch.plt.num_entries = 0;	mod->arch.plt.max_entries = num_plts; 	plt_idx_sec = sechdrs + mod->arch.plt_idx.shndx;	plt_idx_sec->sh_type = SHT_NOBITS;	plt_idx_sec->sh_flags = SHF_ALLOC;	plt_idx_sec->sh_addralign = L1_CACHE_BYTES;	plt_idx_sec->sh_size = (num_plts + 1) * sizeof(struct plt_idx_entry);	mod->arch.plt_idx.num_entries = 0;	mod->arch.plt_idx.max_entries = num_plts; 	if (tramp) {		tramp->sh_type = SHT_NOBITS;		tramp->sh_flags = SHF_EXECINSTR | SHF_ALLOC;		tramp->sh_addralign = __alignof__(struct plt_entry);		tramp->sh_size = NR_FTRACE_PLTS * sizeof(struct plt_entry);	} 	return 0;}