On Mon, Nov 11, 2024 at 12:59:36PM +0100, Peter Zijlstra wrote:
> +#define ASM_ANNOTATE(x) \
> + "911:\n\t" \
> + ".pushsection .discard.annotate,\"M\",@progbits,8\n\t" \
> + ".long 911b - .\n\t" \
> + ".long " __stringify(x) "\n\t" \
> + ".popsection\n\t"
Why mergeable and progbits?
> +static int read_annotate(struct objtool_file *file, void (*func)(int type, struct instruction *insn))
> +{
> + struct section *rsec, *sec;
> + struct instruction *insn;
> + struct reloc *reloc;
> + int type;
> +
> + rsec = find_section_by_name(file->elf, ".rela.discard.annotate");
> + if (!rsec)
> + return 0;
> +
> + sec = find_section_by_name(file->elf, ".discard.annotate");
> + if (!sec)
> + return 0;
Instead of looking for .rela.discard.annotate you can just get it from
sec->rsec.
> +
> + if (sec->sh.sh_entsize != 8) {
> + static bool warn = false;
"warned" ?
> + if (!warn) {
> + WARN("%s: dodgy linker, sh_entsize != 8", sec->name);
> + warn = true;
> + }
Any reason not to make this a fatal error?
> + sec->sh.sh_entsize = 8;
> + }
> +
> + for_each_reloc(rsec, reloc) {
> + insn = find_insn(file, reloc->sym->sec,
> + reloc->sym->offset + reloc_addend(reloc));
> + if (!insn) {
> + WARN("bad .discard.annotate entry: %d", reloc_idx(reloc));
> + return -1;
> + }
Would be nice to print the type here as well.
> @@ -2670,6 +2714,8 @@ static int decode_sections(struct objtoo
> if (ret)
> return ret;
>
> + ret = read_annotate(file, __annotate_nop);
> +
'ret' is ignored here (not that it matters much as this goes away in the
next patch)
--
Josh
