Re: [RFC PATCH v2 12/20] objtool: Warn about non __ro_after_init static key usage in .noinstr

Valentin Schneider
2023-07-31T11:20:16Z

On 28/07/23 10:35, Josh Poimboeuf wrote:
> On Thu, Jul 20, 2023 at 05:30:48PM +0100, Valentin Schneider wrote:
>> +static int validate_static_key(struct instruction *insn, struct insn_state *state)
>> +{
>> + if (state->noinstr && state->instr <= 0) {
>> + if ((strcmp(insn->key_sym->sec->name, ".data..ro_after_init"))) {
>> + WARN_INSN(insn,
>> + "Non __ro_after_init static key \"%s\" in .noinstr section",
>
> For consistency with other warnings, this should start with a lowercase
> "n" and the string literal should be on the same line as the WARN_INSN,
> like
>
> WARN_INSN(insn, "non __ro_after_init static key \"%s\" in .noinstr section",
> ...
>
>> diff --git a/tools/objtool/special.c b/tools/objtool/special.c
>> index 91b1950f5bd8a..1f76cfd815bf3 100644
>> --- a/tools/objtool/special.c
>> +++ b/tools/objtool/special.c
>> @@ -127,6 +127,9 @@ static int get_alt_entry(struct elf *elf, const struct special_entry *entry,
>> return -1;
>> }
>> alt->key_addend = reloc_addend(key_reloc);
>> +
>> + reloc_to_sec_off(key_reloc, &sec, &offset);
>> + alt->key_sym = find_symbol_by_offset(sec, offset & ~2);
>
> Bits 0 and 1 can both store data, should be ~3?
>

Quite so, that needs to be the same as jump_entry_key().

> --
> Josh