/* SPDX-License-Identifier: GPL-2.0 * * Copyright (C) 2014-2017 Linaro Ltd. <ard.biesheuvel@linaro.org> * * Copyright (C) 2018 Andes Technology Corporation <zong@andestech.com> */ #include <linux/elf.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/moduleloader.h>#include <linux/sort.h> unsigned long module_emit_got_entry(struct module *mod, unsigned long val){	struct mod_section *got_sec = &mod->arch.got;	int i = got_sec->num_entries;	struct got_entry *got = get_got_entry(val, got_sec); 	if (got)		return (unsigned long)got; 	/* There is no duplicate entry, create a new one */	got = (struct got_entry *)got_sec->shdr->sh_addr;	got[i] = emit_got_entry(val); 	got_sec->num_entries++;	BUG_ON(got_sec->num_entries > got_sec->max_entries); 	return (unsigned long)&got[i];} unsigned long module_emit_plt_entry(struct module *mod, unsigned long val){	struct mod_section *got_plt_sec = &mod->arch.got_plt;	struct got_entry *got_plt;	struct mod_section *plt_sec = &mod->arch.plt;	struct plt_entry *plt = get_plt_entry(val, plt_sec, got_plt_sec);	int i = plt_sec->num_entries; 	if (plt)		return (unsigned long)plt; 	/* There is no duplicate entry, create a new one */	got_plt = (struct got_entry *)got_plt_sec->shdr->sh_addr;	got_plt[i] = emit_got_entry(val);	plt = (struct plt_entry *)plt_sec->shdr->sh_addr;	plt[i] = emit_plt_entry(val,				(unsigned long)&plt[i],				(unsigned long)&got_plt[i]); 	plt_sec->num_entries++;	got_plt_sec->num_entries++;	BUG_ON(plt_sec->num_entries > plt_sec->max_entries); 	return (unsigned long)&plt[i];} static int cmp_rela(const void *a, const void *b){	const Elf_Rela *x = a, *y = b;	int i; 	/* sort by type, symbol index and addend */	i = cmp_int(x->r_info, y->r_info);	if (i == 0)		i = cmp_int(x->r_addend, y->r_addend);	return i;} static bool duplicate_rela(const Elf_Rela *rela, int idx){	/*	 * Entries are sorted by type, symbol index and addend. That means	 * that, if a duplicate entry exists, it must be in the preceding slot.	 */	return idx > 0 && cmp_rela(rela + idx, rela + idx - 1) == 0;} static void count_max_entries(const Elf_Rela *relas, size_t num,			      unsigned int *plts, unsigned int *gots){	for (size_t i = 0; i < num; i++) {		if (duplicate_rela(relas, i))			continue; 		switch (ELF_R_TYPE(relas[i].r_info)) {		case R_RISCV_CALL_PLT:		case R_RISCV_PLT32:			(*plts)++;			break;		case R_RISCV_GOT_HI20:			(*gots)++;			break;		default:			unreachable();		}	}} static bool rela_needs_plt_got_entry(const Elf_Rela *rela){	switch (ELF_R_TYPE(rela->r_info)) {	case R_RISCV_CALL_PLT:	case R_RISCV_GOT_HI20:	case R_RISCV_PLT32:		return true;	default:		return false;	}} int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,			      char *secstrings, struct module *mod){	size_t num_scratch_relas = 0;	unsigned int num_plts = 0;	unsigned int num_gots = 0;	Elf_Rela *scratch = NULL;	Elf_Rela *new_scratch;	size_t scratch_size = 0;	int i; 	/*	 * Find the empty .got and .plt sections.	 */	for (i = 0; i < ehdr->e_shnum; i++) {		if (!strcmp(secstrings + sechdrs[i].sh_name, ".plt"))			mod->arch.plt.shdr = sechdrs + i;		else if (!strcmp(secstrings + sechdrs[i].sh_name, ".got"))			mod->arch.got.shdr = sechdrs + i;		else if (!strcmp(secstrings + sechdrs[i].sh_name, ".got.plt"))			mod->arch.got_plt.shdr = sechdrs + i;	} 	if (!mod->arch.plt.shdr) {		pr_err("%s: module PLT section(s) missing\n", mod->name);		return -ENOEXEC;	}	if (!mod->arch.got.shdr) {		pr_err("%s: module GOT section(s) missing\n", mod->name);		return -ENOEXEC;	}	if (!mod->arch.got_plt.shdr) {		pr_err("%s: module GOT.PLT section(s) missing\n", mod->name);		return -ENOEXEC;	} 	/* Calculate the maximum number of entries */	for (i = 0; i < ehdr->e_shnum; i++) {		size_t num_relas = 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;		size_t scratch_size_needed; 		if (sechdrs[i].sh_type != SHT_RELA)			continue; 		/* ignore relocations that operate on non-exec sections */		if (!(dst_sec->sh_flags & SHF_EXECINSTR))			continue; 		/*		 * apply_relocate_add() relies on HI20 and LO12 relocation pairs being		 * close together, so sort a copy of the section to avoid interfering.		 */		scratch_size_needed = (num_scratch_relas + num_relas) * sizeof(*scratch);		if (scratch_size_needed > scratch_size) {			scratch_size = scratch_size_needed;			new_scratch = kvrealloc(scratch, scratch_size, GFP_KERNEL);			if (!new_scratch) {				kvfree(scratch);				return -ENOMEM;			}			scratch = new_scratch;		} 		for (size_t j = 0; j < num_relas; j++)			if (rela_needs_plt_got_entry(&relas[j]))				scratch[num_scratch_relas++] = relas[j];	} 	if (scratch) {		/* sort the accumulated PLT/GOT relocations so duplicates are adjacent */		sort(scratch, num_scratch_relas, sizeof(*scratch), cmp_rela, NULL);		count_max_entries(scratch, num_scratch_relas, &num_plts, &num_gots);		kvfree(scratch);	} 	mod->arch.plt.shdr->sh_type = SHT_NOBITS;	mod->arch.plt.shdr->sh_flags = SHF_EXECINSTR | SHF_ALLOC;	mod->arch.plt.shdr->sh_addralign = L1_CACHE_BYTES;	mod->arch.plt.shdr->sh_size = (num_plts + 1) * sizeof(struct plt_entry);	mod->arch.plt.num_entries = 0;	mod->arch.plt.max_entries = num_plts; 	mod->arch.got.shdr->sh_type = SHT_NOBITS;	mod->arch.got.shdr->sh_flags = SHF_ALLOC;	mod->arch.got.shdr->sh_addralign = L1_CACHE_BYTES;	mod->arch.got.shdr->sh_size = (num_gots + 1) * sizeof(struct got_entry);	mod->arch.got.num_entries = 0;	mod->arch.got.max_entries = num_gots; 	mod->arch.got_plt.shdr->sh_type = SHT_NOBITS;	mod->arch.got_plt.shdr->sh_flags = SHF_ALLOC;	mod->arch.got_plt.shdr->sh_addralign = L1_CACHE_BYTES;	mod->arch.got_plt.shdr->sh_size = (num_plts + 1) * sizeof(struct got_entry);	mod->arch.got_plt.num_entries = 0;	mod->arch.got_plt.max_entries = num_plts;	return 0;}