On Fri, Jun 12, 2020 at 04:30:36PM +0200, Peter Zijlstra wrote:
> +int elf_write_insn(struct elf *elf, struct section *sec,
> + unsigned long offset, unsigned int len,
> + const char *insn)
> +{
> + Elf_Data *data = sec->data;
> +
> + if (data->d_type != ELF_T_BYTE || data->d_off) {
> + WARN("write to unexpected data for section: %s", sec->name);
> + return -1;
> + }
> +
> + memcpy(data->d_buf + offset, insn, len);
> + elf_flagdata(data, ELF_C_SET, ELF_F_DIRTY);
> +
> + sec->changed = true;
> + elf->changed = true;
> +
> + return 0;
> +}
> +
> +int elf_write_reloc(struct elf *elf, struct reloc *reloc)
> +{
> + struct section *sec = reloc->sec;
> +
> + if (sec->sh.sh_type == SHT_REL) {
> + reloc->rel.r_info = GELF_R_INFO(reloc->sym->idx, reloc->type);
> + reloc->rel.r_offset = reloc->offset;
> +
> + if (!gelf_update_rel(sec->data, reloc->idx, &reloc->rel)) {
> + WARN_ELF("gelf_update_rel");
> + return -1;
> + }
> + } else {
> + reloc->rela.r_info = GELF_R_INFO(reloc->sym->idx, reloc->type);
> + reloc->rela.r_addend = reloc->addend;
> + reloc->rela.r_offset = reloc->offset;
> +
> + if (!gelf_update_rela(sec->data, reloc->idx, &reloc->rela)) {
> + WARN_ELF("gelf_update_rela");
> + return -1;
> + }
> + }
> +
> + sec->changed = true;
> + elf->changed = true;
> +
> + return 0;
> +}
Doing the change Matt asked for #1, I realized that sec->changed is only
required if we need to rewrite the section header, neither of these two
changes requires that, they already mark the elf data dirty so
elf_update() DTRT.
