// SPDX-License-Identifier: GPL-2.0+
/*
* Author: Hanlu Li <[email protected]>
* Huacai Chen <[email protected]>
*
* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
*/
#define pr_fmt(fmt) "kmod: " fmt
#include <linux/moduleloader.h>
#include <linux/elf.h>
#include <linux/mm.h>
#include <linux/numa.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/ftrace.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <asm/alternative.h>
#include <asm/inst.h>
#include <asm/unwind.h>
static int rela_stack_push(s64 stack_value, s64 *rela_stack, size_t *rela_stack_top)
{
if (*rela_stack_top >= RELA_STACK_DEPTH)
return -ENOEXEC;
rela_stack[(*rela_stack_top)++] = stack_value;
pr_debug("%s stack_value = 0x%llx\n", __func__, stack_value);
return 0;
}
static int rela_stack_pop(s64 *stack_value, s64 *rela_stack, size_t *rela_stack_top)
{
if (*rela_stack_top == 0)
return -ENOEXEC;
*stack_value = rela_stack[--(*rela_stack_top)];
pr_debug("%s stack_value = 0x%llx\n", __func__, *stack_value);
return 0;
}
static int apply_r_larch_none(struct module *mod, u32 *location, Elf_Addr v,
s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
return 0;
}
static int apply_r_larch_error(struct module *me, u32 *location, Elf_Addr v,
s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
pr_err("%s: Unsupport relocation type %u, please add its support.\n", me->name, type);
return -EINVAL;
}
static int apply_r_larch_32(struct module *mod, u32 *location, Elf_Addr v,
s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
*location = v;
return 0;
}
static int apply_r_larch_64(struct module *mod, u32 *location, Elf_Addr v,
s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
*(Elf_Addr *)location = v;
return 0;
}
static int apply_r_larch_sop_push_pcrel(struct module *mod, u32 *location, Elf_Addr v,
s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
return rela_stack_push(v - (u64)location, rela_stack, rela_stack_top);
}
static int apply_r_larch_sop_push_absolute(struct module *mod, u32 *location, Elf_Addr v,
s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
return rela_stack_push(v, rela_stack, rela_stack_top);
}
static int apply_r_larch_sop_push_dup(struct module *mod, u32 *location, Elf_Addr v,
s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
int err = 0;
s64 opr1;
err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
if (err)
return err;
err = rela_stack_push(opr1, rela_stack, rela_stack_top);
if (err)
return err;
err = rela_stack_push(opr1, rela_stack, rela_stack_top);
if (err)
return err;
return 0;
}
static int apply_r_larch_sop_push_plt_pcrel(struct module *mod,
Elf_Shdr *sechdrs, u32 *location, Elf_Addr v,
s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
ptrdiff_t offset = (void *)v - (void *)location;
if (offset >= SZ_128M)
v = module_emit_plt_entry(mod, sechdrs, v);
if (offset < -SZ_128M)
v = module_emit_plt_entry(mod, sechdrs, v);
return apply_r_larch_sop_push_pcrel(mod, location, v, rela_stack, rela_stack_top, type);
}
static int apply_r_larch_sop(struct module *mod, u32 *location, Elf_Addr v,
s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
int err = 0;
s64 opr1, opr2, opr3;
if (type == R_LARCH_SOP_IF_ELSE) {
err = rela_stack_pop(&opr3, rela_stack, rela_stack_top);
if (err)
return err;
}
err = rela_stack_pop(&opr2, rela_stack, rela_stack_top);
if (err)
return err;
err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
if (err)
return err;
switch (type) {
case R_LARCH_SOP_AND:
err = rela_stack_push(opr1 & opr2, rela_stack, rela_stack_top);
break;
case R_LARCH_SOP_ADD:
err = rela_stack_push(opr1 + opr2, rela_stack, rela_stack_top);
break;
case R_LARCH_SOP_SUB:
err = rela_stack_push(opr1 - opr2, rela_stack, rela_stack_top);
break;
case R_LARCH_SOP_SL:
err = rela_stack_push(opr1 << opr2, rela_stack, rela_stack_top);
break;
case R_LARCH_SOP_SR:
err = rela_stack_push(opr1 >> opr2, rela_stack, rela_stack_top);
break;
case R_LARCH_SOP_IF_ELSE:
err = rela_stack_push(opr1 ? opr2 : opr3, rela_stack, rela_stack_top);
break;
default:
pr_err("%s: Unsupport relocation type %u\n", mod->name, type);
return -EINVAL;
}
return err;
}
static int apply_r_larch_sop_imm_field(struct module *mod, u32 *location, Elf_Addr v,
s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
int err = 0;
s64 opr1;
union loongarch_instruction *insn = (union loongarch_instruction *)location;
err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
if (err)
return err;
switch (type) {
case R_LARCH_SOP_POP_32_U_10_12:
if (!unsigned_imm_check(opr1, 12))
goto overflow;
/* (*(uint32_t *) PC) [21 ... 10] = opr [11 ... 0] */
insn->reg2i12_format.immediate = opr1 & 0xfff;
return 0;
case R_LARCH_SOP_POP_32_S_10_12:
if (!signed_imm_check(opr1, 12))
goto overflow;
insn->reg2i12_format.immediate = opr1 & 0xfff;
return 0;
case R_LARCH_SOP_POP_32_S_10_16:
if (!signed_imm_check(opr1, 16))
goto overflow;
insn->reg2i16_format.immediate = opr1 & 0xffff;
return 0;
case R_LARCH_SOP_POP_32_S_10_16_S2:
if (opr1 % 4)
goto unaligned;
if (!signed_imm_check(opr1, 18))
goto overflow;
insn->reg2i16_format.immediate = (opr1 >> 2) & 0xffff;
return 0;
case R_LARCH_SOP_POP_32_S_5_20:
if (!signed_imm_check(opr1, 20))
goto overflow;
insn->reg1i20_format.immediate = (opr1) & 0xfffff;
return 0;
case R_LARCH_SOP_POP_32_S_0_5_10_16_S2:
if (opr1 % 4)
goto unaligned;
if (!signed_imm_check(opr1, 23))
goto overflow;
opr1 >>= 2;
insn->reg1i21_format.immediate_l = opr1 & 0xffff;
insn->reg1i21_format.immediate_h = (opr1 >> 16) & 0x1f;
return 0;
case R_LARCH_SOP_POP_32_S_0_10_10_16_S2:
if (opr1 % 4)
goto unaligned;
if (!signed_imm_check(opr1, 28))
goto overflow;
opr1 >>= 2;
insn->reg0i26_format.immediate_l = opr1 & 0xffff;
insn->reg0i26_format.immediate_h = (opr1 >> 16) & 0x3ff;
return 0;
case R_LARCH_SOP_POP_32_U:
if (!unsigned_imm_check(opr1, 32))
goto overflow;
/* (*(uint32_t *) PC) = opr */
*location = (u32)opr1;
return 0;
default:
pr_err("%s: Unsupport relocation type %u\n", mod->name, type);
return -EINVAL;
}
overflow:
pr_err("module %s: opr1 = 0x%llx overflow! dangerous %s (%u) relocation\n",
mod->name, opr1, __func__, type);
return -ENOEXEC;
unaligned:
pr_err("module %s: opr1 = 0x%llx unaligned! dangerous %s (%u) relocation\n",
mod->name, opr1, __func__, type);
return -ENOEXEC;
}
static int apply_r_larch_add_sub(struct module *mod, u32 *location, Elf_Addr v,
s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
switch (type) {
case R_LARCH_ADD32:
*(s32 *)location += v;
return 0;
case R_LARCH_ADD64:
*(s64 *)location += v;
return 0;
case R_LARCH_SUB32:
*(s32 *)location -= v;
return 0;
case R_LARCH_SUB64:
*(s64 *)location -= v;
return 0;
default:
pr_err("%s: Unsupport relocation type %u\n", mod->name, type);
return -EINVAL;
}
}
static int apply_r_larch_b26(struct module *mod,
Elf_Shdr *sechdrs, u32 *location, Elf_Addr v,
s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
ptrdiff_t offset = (void *)v - (void *)location;
union loongarch_instruction *insn = (union loongarch_instruction *)location;
if (offset >= SZ_128M)
v = module_emit_plt_entry(mod, sechdrs, v);
if (offset < -SZ_128M)
v = module_emit_plt_entry(mod, sechdrs, v);
offset = (void *)v - (void *)location;
if (offset & 3) {
pr_err("module %s: jump offset = 0x%llx unaligned! dangerous R_LARCH_B26 (%u) relocation\n",
mod->name, (long long)offset, type);
return -ENOEXEC;
}
if (!signed_imm_check(offset, 28)) {
pr_err("module %s: jump offset = 0x%llx overflow! dangerous R_LARCH_B26 (%u) relocation\n",
mod->name, (long long)offset, type);
return -ENOEXEC;
}
offset >>= 2;
insn->reg0i26_format.immediate_l = offset & 0xffff;
insn->reg0i26_format.immediate_h = (offset >> 16) & 0x3ff;
return 0;
}
static int apply_r_larch_pcala(struct module *mod, u32 *location, Elf_Addr v,
s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
union loongarch_instruction *insn = (union loongarch_instruction *)location;
/* Use s32 for a sign-extension deliberately. */
s32 offset_hi20 = (void *)((v + 0x800) & ~0xfff) -
(void *)((Elf_Addr)location & ~0xfff);
Elf_Addr anchor = (((Elf_Addr)location) & ~0xfff) + offset_hi20;
ptrdiff_t offset_rem = (void *)v - (void *)anchor;
switch (type) {
case R_LARCH_PCALA_LO12:
insn->reg2i12_format.immediate = v & 0xfff;
break;
case R_LARCH_PCALA_HI20:
v = offset_hi20 >> 12;
insn->reg1i20_format.immediate = v & 0xfffff;
break;
case R_LARCH_PCALA64_LO20:
v = offset_rem >> 32;
insn->reg1i20_format.immediate = v & 0xfffff;
break;
case R_LARCH_PCALA64_HI12:
v = offset_rem >> 52;
insn->reg2i12_format.immediate = v & 0xfff;
break;
default:
pr_err("%s: Unsupport relocation type %u\n", mod->name, type);
return -EINVAL;
}
return 0;
}
static int apply_r_larch_got_pc(struct module *mod,
Elf_Shdr *sechdrs, u32 *location, Elf_Addr v,
s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
Elf_Addr got = module_emit_got_entry(mod, sechdrs, v);
if (!got)
return -EINVAL;
switch (type) {
case R_LARCH_GOT_PC_LO12:
type = R_LARCH_PCALA_LO12;
break;
case R_LARCH_GOT_PC_HI20:
type = R_LARCH_PCALA_HI20;
break;
default:
pr_err("%s: Unsupport relocation type %u\n", mod->name, type);
return -EINVAL;
}
return apply_r_larch_pcala(mod, location, got, rela_stack, rela_stack_top, type);
}
static int apply_r_larch_32_pcrel(struct module *mod, u32 *location, Elf_Addr v,
s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
ptrdiff_t offset = (void *)v - (void *)location;
*(u32 *)location = offset;
return 0;
}
static int apply_r_larch_64_pcrel(struct module *mod, u32 *location, Elf_Addr v,
s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
ptrdiff_t offset = (void *)v - (void *)location;
*(u64 *)location = offset;
return 0;
}
/*
* reloc_handlers_rela() - Apply a particular relocation to a module
* @mod: the module to apply the reloc to
* @location: the address at which the reloc is to be applied
* @v: the value of the reloc, with addend for RELA-style
* @rela_stack: the stack used for store relocation info, LOCAL to THIS module
* @rela_stac_top: where the stack operation(pop/push) applies to
*
* Return: 0 upon success, else -ERRNO
*/
typedef int (*reloc_rela_handler)(struct module *mod, u32 *location, Elf_Addr v,
s64 *rela_stack, size_t *rela_stack_top, unsigned int type);
/* The handlers for known reloc types */
static reloc_rela_handler reloc_rela_handlers[] = {
[R_LARCH_NONE ... R_LARCH_64_PCREL] = apply_r_larch_error,
[R_LARCH_NONE] = apply_r_larch_none,
[R_LARCH_32] = apply_r_larch_32,
[R_LARCH_64] = apply_r_larch_64,
[R_LARCH_MARK_LA] = apply_r_larch_none,
[R_LARCH_MARK_PCREL] = apply_r_larch_none,
[R_LARCH_SOP_PUSH_PCREL] = apply_r_larch_sop_push_pcrel,
[R_LARCH_SOP_PUSH_ABSOLUTE] = apply_r_larch_sop_push_absolute,
[R_LARCH_SOP_PUSH_DUP] = apply_r_larch_sop_push_dup,
[R_LARCH_SOP_SUB ... R_LARCH_SOP_IF_ELSE] = apply_r_larch_sop,
[R_LARCH_SOP_POP_32_S_10_5 ... R_LARCH_SOP_POP_32_U] = apply_r_larch_sop_imm_field,
[R_LARCH_ADD32 ... R_LARCH_SUB64] = apply_r_larch_add_sub,
[R_LARCH_PCALA_HI20...R_LARCH_PCALA64_HI12] = apply_r_larch_pcala,
[R_LARCH_32_PCREL] = apply_r_larch_32_pcrel,
[R_LARCH_64_PCREL] = apply_r_larch_64_pcrel,
};
int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
unsigned int symindex, unsigned int relsec,
struct module *mod)
{
int i, err;
unsigned int type;
s64 rela_stack[RELA_STACK_DEPTH];
size_t rela_stack_top = 0;
reloc_rela_handler handler;
void *location;
Elf_Addr v;
Elf_Sym *sym;
Elf_Rela *rel = (void *) sechdrs[relsec].sh_addr;
pr_debug("%s: Applying relocate section %u to %u\n", __func__, relsec,
sechdrs[relsec].sh_info);
rela_stack_top = 0;
for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
/* This is where to make the change */
location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr + rel[i].r_offset;
/* This is the symbol it is referring to */
sym = (Elf_Sym *)sechdrs[symindex].sh_addr + ELF_R_SYM(rel[i].r_info);
if (IS_ERR_VALUE(sym->st_value)) {
/* Ignore unresolved weak symbol */
if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
continue;
pr_warn("%s: Unknown symbol %s\n", mod->name, strtab + sym->st_name);
return -ENOENT;
}
type = ELF_R_TYPE(rel[i].r_info);
if (type < ARRAY_SIZE(reloc_rela_handlers))
handler = reloc_rela_handlers[type];
else
handler = NULL;
if (!handler) {
pr_err("%s: Unknown relocation type %u\n", mod->name, type);
return -EINVAL;
}
pr_debug("type %d st_value %llx r_addend %llx loc %llx\n",
(int)ELF_R_TYPE(rel[i].r_info),
sym->st_value, rel[i].r_addend, (u64)location);
v = sym->st_value + rel[i].r_addend;
switch (type) {
case R_LARCH_B26:
err = apply_r_larch_b26(mod, sechdrs, location,
v, rela_stack, &rela_stack_top, type);
break;
case R_LARCH_GOT_PC_HI20...R_LARCH_GOT_PC_LO12:
err = apply_r_larch_got_pc(mod, sechdrs, location,
v, rela_stack, &rela_stack_top, type);
break;
case R_LARCH_SOP_PUSH_PLT_PCREL:
err = apply_r_larch_sop_push_plt_pcrel(mod, sechdrs, location,
v, rela_stack, &rela_stack_top, type);
break;
default:
err = handler(mod, location, v, rela_stack, &rela_stack_top, type);
}
if (err)
return err;
}
return 0;
}
static void module_init_ftrace_plt(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs, struct module *mod)
{
#ifdef CONFIG_DYNAMIC_FTRACE
struct plt_entry *ftrace_plts;
ftrace_plts = (void *)sechdrs->sh_addr;
ftrace_plts[FTRACE_PLT_IDX] = emit_plt_entry(FTRACE_ADDR);
if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS))
ftrace_plts[FTRACE_REGS_PLT_IDX] = emit_plt_entry(FTRACE_REGS_ADDR);
mod->arch.ftrace_trampolines = ftrace_plts;
#endif
}
int module_finalize(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs, struct module *mod)
{
const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
const Elf_Shdr *s, *alt = NULL, *orc = NULL, *orc_ip = NULL, *ftrace = NULL;
for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
if (!strcmp(".altinstructions", secstrs + s->sh_name))
alt = s;
if (!strcmp(".orc_unwind", secstrs + s->sh_name))
orc = s;
if (!strcmp(".orc_unwind_ip", secstrs + s->sh_name))
orc_ip = s;
if (!strcmp(".ftrace_trampoline", secstrs + s->sh_name))
ftrace = s;
}
if (alt)
apply_alternatives((void *)alt->sh_addr, (void *)alt->sh_addr + alt->sh_size);
if (orc && orc_ip)
unwind_module_init(mod, (void *)orc_ip->sh_addr, orc_ip->sh_size, (void *)orc->sh_addr, orc->sh_size);
if (ftrace)
module_init_ftrace_plt(hdr, ftrace, mod);
return 0;
}
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