[thirdparty/kernel/stable.git] / arch / loongarch / kernel / module-sections.c

// 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>

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 is_rela_equal(const Elf_Rela *x, const Elf_Rela *y)
{
	return x->r_info == y->r_info && x->r_addend == y->r_addend;
}

static bool duplicate_rela(const Elf_Rela *rela, int idx)
{
	int i;

	for (i = 0; i < idx; i++) {
		if (is_rela_equal(&rela[i], &rela[idx]))
			return true;
	}

	return false;
}

static void count_max_entries(Elf_Rela *relas, int num,
			      unsigned int *plts, unsigned int *gots)
{
	unsigned int i, type;

	for (i = 0; i < num; i++) {
		type = ELF_R_TYPE(relas[i].r_info);
		switch (type) {
		case R_LARCH_SOP_PUSH_PLT_PCREL:
		case R_LARCH_B26:
			if (!duplicate_rela(relas, i))
				(*plts)++;
			break;
		case R_LARCH_GOT_PC_HI20:
			if (!duplicate_rela(relas, i))
				(*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;
}
Commit	Line	Data
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,
59b3d4a9 XR	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))
fcdfe9d2 HC	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:
9bd1e380 XR	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"))
28ac0a9e QZ	121	tramp = sechdrs + i;
fcdfe9d2 HC	122	}
fcdfe9d2 HC	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	}
fcdfe9d2 HC	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;
fcdfe9d2 HC	185	}